1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  * Copyright 2011 Joyent, Inc.  All rights reserved.
  25  * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
  26  */
  27 
  28 #include <sys/types.h>
  29 #include <sys/callb.h>
  30 #include <sys/sdt.h>
  31 #include <sys/strsubr.h>
  32 #include <sys/strsun.h>
  33 #include <sys/vlan.h>
  34 #include <sys/stack.h>
  35 #include <sys/archsystm.h>
  36 #include <inet/ipsec_impl.h>
  37 #include <inet/ip_impl.h>
  38 #include <inet/sadb.h>
  39 #include <inet/ipsecesp.h>
  40 #include <inet/ipsecah.h>
  41 #include <inet/ip6.h>
  42 
  43 #include <sys/mac_impl.h>
  44 #include <sys/mac_client_impl.h>
  45 #include <sys/mac_client_priv.h>
  46 #include <sys/mac_soft_ring.h>
  47 #include <sys/mac_flow_impl.h>
  48 
  49 static mac_tx_cookie_t mac_tx_single_ring_mode(mac_soft_ring_set_t *, mblk_t *,
  50     uintptr_t, uint16_t, mblk_t **);
  51 static mac_tx_cookie_t mac_tx_serializer_mode(mac_soft_ring_set_t *, mblk_t *,
  52     uintptr_t, uint16_t, mblk_t **);
  53 static mac_tx_cookie_t mac_tx_fanout_mode(mac_soft_ring_set_t *, mblk_t *,
  54     uintptr_t, uint16_t, mblk_t **);
  55 static mac_tx_cookie_t mac_tx_bw_mode(mac_soft_ring_set_t *, mblk_t *,
  56     uintptr_t, uint16_t, mblk_t **);
  57 static mac_tx_cookie_t mac_tx_aggr_mode(mac_soft_ring_set_t *, mblk_t *,
  58     uintptr_t, uint16_t, mblk_t **);
  59 
  60 typedef struct mac_tx_mode_s {
  61         mac_tx_srs_mode_t       mac_tx_mode;
  62         mac_tx_func_t           mac_tx_func;
  63 } mac_tx_mode_t;
  64 
  65 /*
  66  * There are seven modes of operation on the Tx side. These modes get set
  67  * in mac_tx_srs_setup(). Except for the experimental TX_SERIALIZE mode,
  68  * none of the other modes are user configurable. They get selected by
  69  * the system depending upon whether the link (or flow) has multiple Tx
  70  * rings or a bandwidth configured, or if the link is an aggr, etc.
  71  *
  72  * When the Tx SRS is operating in aggr mode (st_mode) or if there are
  73  * multiple Tx rings owned by Tx SRS, then each Tx ring (pseudo or
  74  * otherwise) will have a soft ring associated with it. These soft rings
  75  * are stored in srs_tx_soft_rings[] array.
  76  *
  77  * Additionally in the case of aggr, there is the st_soft_rings[] array
  78  * in the mac_srs_tx_t structure. This array is used to store the same
  79  * set of soft rings that are present in srs_tx_soft_rings[] array but
  80  * in a different manner. The soft ring associated with the pseudo Tx
  81  * ring is saved at mr_index (of the pseudo ring) in st_soft_rings[]
  82  * array. This helps in quickly getting the soft ring associated with the
  83  * Tx ring when aggr_find_tx_ring() returns the pseudo Tx ring that is to
  84  * be used for transmit.
  85  */
  86 mac_tx_mode_t mac_tx_mode_list[] = {
  87         {SRS_TX_DEFAULT,        mac_tx_single_ring_mode},
  88         {SRS_TX_SERIALIZE,      mac_tx_serializer_mode},
  89         {SRS_TX_FANOUT,         mac_tx_fanout_mode},
  90         {SRS_TX_BW,             mac_tx_bw_mode},
  91         {SRS_TX_BW_FANOUT,      mac_tx_bw_mode},
  92         {SRS_TX_AGGR,           mac_tx_aggr_mode},
  93         {SRS_TX_BW_AGGR,        mac_tx_bw_mode}
  94 };
  95 
  96 /*
  97  * Soft Ring Set (SRS) - The Run time code that deals with
  98  * dynamic polling from the hardware, bandwidth enforcement,
  99  * fanout etc.
 100  *
 101  * We try to use H/W classification on NIC and assign traffic for
 102  * a MAC address to a particular Rx ring or ring group. There is a
 103  * 1-1 mapping between a SRS and a Rx ring. The SRS dynamically
 104  * switches the underlying Rx ring between interrupt and
 105  * polling mode and enforces any specified B/W control.
 106  *
 107  * There is always a SRS created and tied to each H/W and S/W rule.
 108  * Whenever we create a H/W rule, we always add the the same rule to
 109  * S/W classifier and tie a SRS to it.
 110  *
 111  * In case a B/W control is specified, it is broken into bytes
 112  * per ticks and as soon as the quota for a tick is exhausted,
 113  * the underlying Rx ring is forced into poll mode for remainder of
 114  * the tick. The SRS poll thread only polls for bytes that are
 115  * allowed to come in the SRS. We typically let 4x the configured
 116  * B/W worth of packets to come in the SRS (to prevent unnecessary
 117  * drops due to bursts) but only process the specified amount.
 118  *
 119  * A MAC client (e.g. a VNIC or aggr) can have 1 or more
 120  * Rx rings (and corresponding SRSs) assigned to it. The SRS
 121  * in turn can have softrings to do protocol level fanout or
 122  * softrings to do S/W based fanout or both. In case the NIC
 123  * has no Rx rings, we do S/W classification to respective SRS.
 124  * The S/W classification rule is always setup and ready. This
 125  * allows the MAC layer to reassign Rx rings whenever needed
 126  * but packets still continue to flow via the default path and
 127  * getting S/W classified to correct SRS.
 128  *
 129  * The SRS's are used on both Tx and Rx side. They use the same
 130  * data structure but the processing routines have slightly different
 131  * semantics due to the fact that Rx side needs to do dynamic
 132  * polling etc.
 133  *
 134  * Dynamic Polling Notes
 135  * =====================
 136  *
 137  * Each Soft ring set is capable of switching its Rx ring between
 138  * interrupt and poll mode and actively 'polls' for packets in
 139  * poll mode. If the SRS is implementing a B/W limit, it makes
 140  * sure that only Max allowed packets are pulled in poll mode
 141  * and goes to poll mode as soon as B/W limit is exceeded. As
 142  * such, there are no overheads to implement B/W limits.
 143  *
 144  * In poll mode, its better to keep the pipeline going where the
 145  * SRS worker thread keeps processing packets and poll thread
 146  * keeps bringing more packets (specially if they get to run
 147  * on different CPUs). This also prevents the overheads associated
 148  * by excessive signalling (on NUMA machines, this can be
 149  * pretty devastating). The exception is latency optimized case
 150  * where worker thread does no work and interrupt and poll thread
 151  * are allowed to do their own drain.
 152  *
 153  * We use the following policy to control Dynamic Polling:
 154  * 1) We switch to poll mode anytime the processing
 155  *    thread causes a backlog to build up in SRS and
 156  *    its associated Soft Rings (sr_poll_pkt_cnt > 0).
 157  * 2) As long as the backlog stays under the low water
 158  *    mark (sr_lowat), we poll the H/W for more packets.
 159  * 3) If the backlog (sr_poll_pkt_cnt) exceeds low
 160  *    water mark, we stay in poll mode but don't poll
 161  *    the H/W for more packets.
 162  * 4) Anytime in polling mode, if we poll the H/W for
 163  *    packets and find nothing plus we have an existing
 164  *    backlog (sr_poll_pkt_cnt > 0), we stay in polling
 165  *    mode but don't poll the H/W for packets anymore
 166  *    (let the polling thread go to sleep).
 167  * 5) Once the backlog is relived (packets are processed)
 168  *    we reenable polling (by signalling the poll thread)
 169  *    only when the backlog dips below sr_poll_thres.
 170  * 6) sr_hiwat is used exclusively when we are not
 171  *    polling capable and is used to decide when to
 172  *    drop packets so the SRS queue length doesn't grow
 173  *    infinitely.
 174  *
 175  * NOTE: Also see the block level comment on top of mac_soft_ring.c
 176  */
 177 
 178 /*
 179  * mac_latency_optimize
 180  *
 181  * Controls whether the poll thread can process the packets inline
 182  * or let the SRS worker thread do the processing. This applies if
 183  * the SRS was not being processed. For latency sensitive traffic,
 184  * this needs to be true to allow inline processing. For throughput
 185  * under load, this should be false.
 186  *
 187  * This (and other similar) tunable should be rolled into a link
 188  * or flow specific workload hint that can be set using dladm
 189  * linkprop (instead of multiple such tunables).
 190  */
 191 boolean_t mac_latency_optimize = B_TRUE;
 192 
 193 /*
 194  * MAC_RX_SRS_ENQUEUE_CHAIN and MAC_TX_SRS_ENQUEUE_CHAIN
 195  *
 196  * queue a mp or chain in soft ring set and increment the
 197  * local count (srs_count) for the SRS and the shared counter
 198  * (srs_poll_pkt_cnt - shared between SRS and its soft rings
 199  * to track the total unprocessed packets for polling to work
 200  * correctly).
 201  *
 202  * The size (total bytes queued) counters are incremented only
 203  * if we are doing B/W control.
 204  */
 205 #define MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {         \
 206         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 207         if ((mac_srs)->srs_last != NULL)                             \
 208                 (mac_srs)->srs_last->b_next = (head);                     \
 209         else                                                            \
 210                 (mac_srs)->srs_first = (head);                               \
 211         (mac_srs)->srs_last = (tail);                                        \
 212         (mac_srs)->srs_count += count;                                       \
 213 }
 214 
 215 #define MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {      \
 216         mac_srs_rx_t    *srs_rx = &(mac_srs)->srs_rx;                    \
 217                                                                         \
 218         MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz);          \
 219         srs_rx->sr_poll_pkt_cnt += count;                            \
 220         ASSERT(srs_rx->sr_poll_pkt_cnt > 0);                              \
 221         if ((mac_srs)->srs_type & SRST_BW_CONTROL) {                     \
 222                 (mac_srs)->srs_size += (sz);                         \
 223                 mutex_enter(&(mac_srs)->srs_bw->mac_bw_lock);         \
 224                 (mac_srs)->srs_bw->mac_bw_sz += (sz);                     \
 225                 mutex_exit(&(mac_srs)->srs_bw->mac_bw_lock);          \
 226         }                                                               \
 227 }
 228 
 229 #define MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz) {      \
 230         mac_srs->srs_state |= SRS_ENQUEUED;                          \
 231         MAC_SRS_ENQUEUE_CHAIN(mac_srs, head, tail, count, sz);          \
 232         if ((mac_srs)->srs_type & SRST_BW_CONTROL) {                     \
 233                 (mac_srs)->srs_size += (sz);                         \
 234                 (mac_srs)->srs_bw->mac_bw_sz += (sz);                     \
 235         }                                                               \
 236 }
 237 
 238 /*
 239  * Turn polling on routines
 240  */
 241 #define MAC_SRS_POLLING_ON(mac_srs) {                                   \
 242         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 243         if (((mac_srs)->srs_state &                                      \
 244             (SRS_POLLING_CAPAB|SRS_POLLING)) == SRS_POLLING_CAPAB) {    \
 245                 (mac_srs)->srs_state |= SRS_POLLING;                 \
 246                 (void) mac_hwring_disable_intr((mac_ring_handle_t)      \
 247                     (mac_srs)->srs_ring);                            \
 248                 (mac_srs)->srs_rx.sr_poll_on++;                              \
 249         }                                                               \
 250 }
 251 
 252 #define MAC_SRS_WORKER_POLLING_ON(mac_srs) {                            \
 253         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 254         if (((mac_srs)->srs_state &                                      \
 255             (SRS_POLLING_CAPAB|SRS_WORKER|SRS_POLLING)) ==              \
 256             (SRS_POLLING_CAPAB|SRS_WORKER)) {                           \
 257                 (mac_srs)->srs_state |= SRS_POLLING;                 \
 258                 (void) mac_hwring_disable_intr((mac_ring_handle_t)      \
 259                     (mac_srs)->srs_ring);                            \
 260                 (mac_srs)->srs_rx.sr_worker_poll_on++;                       \
 261         }                                                               \
 262 }
 263 
 264 /*
 265  * MAC_SRS_POLL_RING
 266  *
 267  * Signal the SRS poll thread to poll the underlying H/W ring
 268  * provided it wasn't already polling (SRS_GET_PKTS was set).
 269  *
 270  * Poll thread gets to run only from mac_rx_srs_drain() and only
 271  * if the drain was being done by the worker thread.
 272  */
 273 #define MAC_SRS_POLL_RING(mac_srs) {                                    \
 274         mac_srs_rx_t    *srs_rx = &(mac_srs)->srs_rx;                    \
 275                                                                         \
 276         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 277         srs_rx->sr_poll_thr_sig++;                                   \
 278         if (((mac_srs)->srs_state &                                      \
 279             (SRS_POLLING_CAPAB|SRS_WORKER|SRS_GET_PKTS)) ==             \
 280                 (SRS_WORKER|SRS_POLLING_CAPAB)) {                       \
 281                 (mac_srs)->srs_state |= SRS_GET_PKTS;                        \
 282                 cv_signal(&(mac_srs)->srs_cv);                           \
 283         } else {                                                        \
 284                 srs_rx->sr_poll_thr_busy++;                          \
 285         }                                                               \
 286 }
 287 
 288 /*
 289  * MAC_SRS_CHECK_BW_CONTROL
 290  *
 291  * Check to see if next tick has started so we can reset the
 292  * SRS_BW_ENFORCED flag and allow more packets to come in the
 293  * system.
 294  */
 295 #define MAC_SRS_CHECK_BW_CONTROL(mac_srs) {                             \
 296         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 297         ASSERT(((mac_srs)->srs_type & SRST_TX) ||                        \
 298             MUTEX_HELD(&(mac_srs)->srs_bw->mac_bw_lock));             \
 299         clock_t now = ddi_get_lbolt();                                  \
 300         if ((mac_srs)->srs_bw->mac_bw_curr_time != now) {         \
 301                 (mac_srs)->srs_bw->mac_bw_curr_time = now;                \
 302                 (mac_srs)->srs_bw->mac_bw_used = 0;                       \
 303                 if ((mac_srs)->srs_bw->mac_bw_state & SRS_BW_ENFORCED)        \
 304                         (mac_srs)->srs_bw->mac_bw_state &= ~SRS_BW_ENFORCED; \
 305         }                                                               \
 306 }
 307 
 308 /*
 309  * MAC_SRS_WORKER_WAKEUP
 310  *
 311  * Wake up the SRS worker thread to process the queue as long as
 312  * no one else is processing the queue. If we are optimizing for
 313  * latency, we wake up the worker thread immediately or else we
 314  * wait mac_srs_worker_wakeup_ticks before worker thread gets
 315  * woken up.
 316  */
 317 int mac_srs_worker_wakeup_ticks = 0;
 318 #define MAC_SRS_WORKER_WAKEUP(mac_srs) {                                \
 319         ASSERT(MUTEX_HELD(&(mac_srs)->srs_lock));                        \
 320         if (!((mac_srs)->srs_state & SRS_PROC) &&                        \
 321                 (mac_srs)->srs_tid == NULL) {                                \
 322                 if (((mac_srs)->srs_state & SRS_LATENCY_OPT) ||          \
 323                         (mac_srs_worker_wakeup_ticks == 0))             \
 324                         cv_signal(&(mac_srs)->srs_async);                \
 325                 else                                                    \
 326                         (mac_srs)->srs_tid =                         \
 327                                 timeout(mac_srs_fire, (mac_srs),        \
 328                                         mac_srs_worker_wakeup_ticks);   \
 329         }                                                               \
 330 }
 331 
 332 #define TX_BANDWIDTH_MODE(mac_srs)                              \
 333         ((mac_srs)->srs_tx.st_mode == SRS_TX_BW ||           \
 334             (mac_srs)->srs_tx.st_mode == SRS_TX_BW_FANOUT || \
 335             (mac_srs)->srs_tx.st_mode == SRS_TX_BW_AGGR)
 336 
 337 #define TX_SRS_TO_SOFT_RING(mac_srs, head, hint) {                      \
 338         if (tx_mode == SRS_TX_BW_FANOUT)                                \
 339                 (void) mac_tx_fanout_mode(mac_srs, head, hint, 0, NULL);\
 340         else                                                            \
 341                 (void) mac_tx_aggr_mode(mac_srs, head, hint, 0, NULL);  \
 342 }
 343 
 344 /*
 345  * MAC_TX_SRS_BLOCK
 346  *
 347  * Always called from mac_tx_srs_drain() function. SRS_TX_BLOCKED
 348  * will be set only if srs_tx_woken_up is FALSE. If
 349  * srs_tx_woken_up is TRUE, it indicates that the wakeup arrived
 350  * before we grabbed srs_lock to set SRS_TX_BLOCKED. We need to
 351  * attempt to transmit again and not setting SRS_TX_BLOCKED does
 352  * that.
 353  */
 354 #define MAC_TX_SRS_BLOCK(srs, mp)       {                       \
 355         ASSERT(MUTEX_HELD(&(srs)->srs_lock));                    \
 356         if ((srs)->srs_tx.st_woken_up) {                     \
 357                 (srs)->srs_tx.st_woken_up = B_FALSE;         \
 358         } else {                                                \
 359                 ASSERT(!((srs)->srs_state & SRS_TX_BLOCKED));    \
 360                 (srs)->srs_state |= SRS_TX_BLOCKED;          \
 361                 (srs)->srs_tx.st_stat.mts_blockcnt++;                \
 362         }                                                       \
 363 }
 364 
 365 /*
 366  * MAC_TX_SRS_TEST_HIWAT
 367  *
 368  * Called before queueing a packet onto Tx SRS to test and set
 369  * SRS_TX_HIWAT if srs_count exceeds srs_tx_hiwat.
 370  */
 371 #define MAC_TX_SRS_TEST_HIWAT(srs, mp, tail, cnt, sz, cookie) {         \
 372         boolean_t enqueue = 1;                                          \
 373                                                                         \
 374         if ((srs)->srs_count > (srs)->srs_tx.st_hiwat) {               \
 375                 /*                                                      \
 376                  * flow-controlled. Store srs in cookie so that it      \
 377                  * can be returned as mac_tx_cookie_t to client         \
 378                  */                                                     \
 379                 (srs)->srs_state |= SRS_TX_HIWAT;                    \
 380                 cookie = (mac_tx_cookie_t)srs;                          \
 381                 (srs)->srs_tx.st_hiwat_cnt++;                                \
 382                 if ((srs)->srs_count > (srs)->srs_tx.st_max_q_cnt) {   \
 383                         /* increment freed stats */                     \
 384                         (srs)->srs_tx.st_stat.mts_sdrops += cnt;     \
 385                         /*                                              \
 386                          * b_prev may be set to the fanout hint         \
 387                          * hence can't use freemsg directly             \
 388                          */                                             \
 389                         mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);    \
 390                         DTRACE_PROBE1(tx_queued_hiwat,                  \
 391                             mac_soft_ring_set_t *, srs);                \
 392                         enqueue = 0;                                    \
 393                 }                                                       \
 394         }                                                               \
 395         if (enqueue)                                                    \
 396                 MAC_TX_SRS_ENQUEUE_CHAIN(srs, mp, tail, cnt, sz);       \
 397 }
 398 
 399 /* Some utility macros */
 400 #define MAC_SRS_BW_LOCK(srs)                                            \
 401         if (!(srs->srs_type & SRST_TX))                                  \
 402                 mutex_enter(&srs->srs_bw->mac_bw_lock);
 403 
 404 #define MAC_SRS_BW_UNLOCK(srs)                                          \
 405         if (!(srs->srs_type & SRST_TX))                                  \
 406                 mutex_exit(&srs->srs_bw->mac_bw_lock);
 407 
 408 #define MAC_TX_SRS_DROP_MESSAGE(srs, mp, cookie) {              \
 409         mac_pkt_drop(NULL, NULL, mp, B_FALSE);                  \
 410         /* increment freed stats */                             \
 411         mac_srs->srs_tx.st_stat.mts_sdrops++;                        \
 412         cookie = (mac_tx_cookie_t)srs;                          \
 413 }
 414 
 415 #define MAC_TX_SET_NO_ENQUEUE(srs, mp_chain, ret_mp, cookie) {          \
 416         mac_srs->srs_state |= SRS_TX_WAKEUP_CLIENT;                  \
 417         cookie = (mac_tx_cookie_t)srs;                                  \
 418         *ret_mp = mp_chain;                                             \
 419 }
 420 
 421 /*
 422  * MAC_RX_SRS_TOODEEP
 423  *
 424  * Macro called as part of receive-side processing to determine if handling
 425  * can occur in situ (in the interrupt thread) or if it should be left to a
 426  * worker thread.  Note that the constant used to make this determination is
 427  * not entirely made-up, and is a result of some emprical validation. That
 428  * said, the constant is left as a static variable to allow it to be
 429  * dynamically tuned in the field if and as needed.
 430  */
 431 static uintptr_t mac_rx_srs_stack_needed = 10240;
 432 static uint_t mac_rx_srs_stack_toodeep;
 433 
 434 #ifndef STACK_GROWTH_DOWN
 435 #error Downward stack growth assumed.
 436 #endif
 437 
 438 #define MAC_RX_SRS_TOODEEP() (STACK_BIAS + (uintptr_t)getfp() - \
 439         (uintptr_t)curthread->t_stkbase < mac_rx_srs_stack_needed && \
 440         ++mac_rx_srs_stack_toodeep)
 441 
 442 
 443 /*
 444  * Drop the rx packet and advance to the next one in the chain.
 445  */
 446 static void
 447 mac_rx_drop_pkt(mac_soft_ring_set_t *srs, mblk_t *mp)
 448 {
 449         mac_srs_rx_t    *srs_rx = &srs->srs_rx;
 450 
 451         ASSERT(mp->b_next == NULL);
 452         mutex_enter(&srs->srs_lock);
 453         MAC_UPDATE_SRS_COUNT_LOCKED(srs, 1);
 454         MAC_UPDATE_SRS_SIZE_LOCKED(srs, msgdsize(mp));
 455         mutex_exit(&srs->srs_lock);
 456 
 457         srs_rx->sr_stat.mrs_sdrops++;
 458         freemsg(mp);
 459 }
 460 
 461 /* DATAPATH RUNTIME ROUTINES */
 462 
 463 /*
 464  * mac_srs_fire
 465  *
 466  * Timer callback routine for waking up the SRS worker thread.
 467  */
 468 static void
 469 mac_srs_fire(void *arg)
 470 {
 471         mac_soft_ring_set_t *mac_srs = (mac_soft_ring_set_t *)arg;
 472 
 473         mutex_enter(&mac_srs->srs_lock);
 474         if (mac_srs->srs_tid == 0) {
 475                 mutex_exit(&mac_srs->srs_lock);
 476                 return;
 477         }
 478 
 479         mac_srs->srs_tid = 0;
 480         if (!(mac_srs->srs_state & SRS_PROC))
 481                 cv_signal(&mac_srs->srs_async);
 482 
 483         mutex_exit(&mac_srs->srs_lock);
 484 }
 485 
 486 /*
 487  * 'hint' is fanout_hint (type of uint64_t) which is given by the TCP/IP stack,
 488  * and it is used on the TX path.
 489  */
 490 #define HASH_HINT(hint) \
 491         ((hint) ^ ((hint) >> 24) ^ ((hint) >> 16) ^ ((hint) >> 8))
 492 
 493 
 494 /*
 495  * hash based on the src address and the port information.
 496  */
 497 #define HASH_ADDR(src, ports)                                   \
 498         (ntohl((src)) ^ ((ports) >> 24) ^ ((ports) >> 16) ^ \
 499         ((ports) >> 8) ^ (ports))
 500 
 501 #define COMPUTE_INDEX(key, sz)  (key % sz)
 502 
 503 #define FANOUT_ENQUEUE_MP(head, tail, cnt, bw_ctl, sz, sz0, mp) {       \
 504         if ((tail) != NULL) {                                           \
 505                 ASSERT((tail)->b_next == NULL);                              \
 506                 (tail)->b_next = (mp);                                       \
 507         } else {                                                        \
 508                 ASSERT((head) == NULL);                                 \
 509                 (head) = (mp);                                          \
 510         }                                                               \
 511         (tail) = (mp);                                                  \
 512         (cnt)++;                                                        \
 513         if ((bw_ctl))                                                   \
 514                 (sz) += (sz0);                                          \
 515 }
 516 
 517 #define MAC_FANOUT_DEFAULT      0
 518 #define MAC_FANOUT_RND_ROBIN    1
 519 int mac_fanout_type = MAC_FANOUT_DEFAULT;
 520 
 521 #define MAX_SR_TYPES    3
 522 /* fanout types for port based hashing */
 523 enum pkt_type {
 524         V4_TCP = 0,
 525         V4_UDP,
 526         OTH,
 527         UNDEF
 528 };
 529 
 530 /*
 531  * In general we do port based hashing to spread traffic over different
 532  * softrings. The below tunables allow to override that behavior. Setting one
 533  * (depending on IPv6 or IPv4) to B_TRUE allows a fanout based on src
 534  * IPv6 or IPv4 address. This behavior is also applicable to IPv6 packets
 535  * carrying multiple optional headers and other uncommon packet types.
 536  */
 537 boolean_t mac_src_ipv6_fanout = B_FALSE;
 538 boolean_t mac_src_ipv4_fanout = B_FALSE;
 539 
 540 /*
 541  * Pair of local and remote ports in the transport header
 542  */
 543 #define PORTS_SIZE 4
 544 
 545 /*
 546  * mac_rx_srs_proto_fanout
 547  *
 548  * This routine delivers packets destined to an SRS into one of the
 549  * protocol soft rings.
 550  *
 551  * Given a chain of packets we need to split it up into multiple sub chains
 552  * destined into TCP, UDP or OTH soft ring. Instead of entering
 553  * the soft ring one packet at a time, we want to enter it in the form of a
 554  * chain otherwise we get this start/stop behaviour where the worker thread
 555  * goes to sleep and then next packets comes in forcing it to wake up etc.
 556  */
 557 static void
 558 mac_rx_srs_proto_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *head)
 559 {
 560         struct ether_header             *ehp;
 561         struct ether_vlan_header        *evhp;
 562         uint32_t                        sap;
 563         ipha_t                          *ipha;
 564         uint8_t                         *dstaddr;
 565         size_t                          hdrsize;
 566         mblk_t                          *mp;
 567         mblk_t                          *headmp[MAX_SR_TYPES];
 568         mblk_t                          *tailmp[MAX_SR_TYPES];
 569         int                             cnt[MAX_SR_TYPES];
 570         size_t                          sz[MAX_SR_TYPES];
 571         size_t                          sz1;
 572         boolean_t                       bw_ctl;
 573         boolean_t                       hw_classified;
 574         boolean_t                       dls_bypass;
 575         boolean_t                       is_ether;
 576         boolean_t                       is_unicast;
 577         enum pkt_type                   type;
 578         mac_client_impl_t               *mcip = mac_srs->srs_mcip;
 579 
 580         is_ether = (mcip->mci_mip->mi_info.mi_nativemedia == DL_ETHER);
 581         bw_ctl = ((mac_srs->srs_type & SRST_BW_CONTROL) != 0);
 582 
 583         /*
 584          * If we don't have a Rx ring, S/W classification would have done
 585          * its job and its a packet meant for us. If we were polling on
 586          * the default ring (i.e. there was a ring assigned to this SRS),
 587          * then we need to make sure that the mac address really belongs
 588          * to us.
 589          */
 590         hw_classified = mac_srs->srs_ring != NULL &&
 591             mac_srs->srs_ring->mr_classify_type == MAC_HW_CLASSIFIER;
 592 
 593         /*
 594          * Special clients (eg. VLAN, non ether, etc) need DLS
 595          * processing in the Rx path. SRST_DLS_BYPASS will be clear for
 596          * such SRSs. Another way of disabling bypass is to set the
 597          * MCIS_RX_BYPASS_DISABLE flag.
 598          */
 599         dls_bypass = ((mac_srs->srs_type & SRST_DLS_BYPASS) != 0) &&
 600             ((mcip->mci_state_flags & MCIS_RX_BYPASS_DISABLE) == 0);
 601 
 602         bzero(headmp, MAX_SR_TYPES * sizeof (mblk_t *));
 603         bzero(tailmp, MAX_SR_TYPES * sizeof (mblk_t *));
 604         bzero(cnt, MAX_SR_TYPES * sizeof (int));
 605         bzero(sz, MAX_SR_TYPES * sizeof (size_t));
 606 
 607         /*
 608          * We got a chain from SRS that we need to send to the soft rings.
 609          * Since squeues for TCP & IPv4 sap poll their soft rings (for
 610          * performance reasons), we need to separate out v4_tcp, v4_udp
 611          * and the rest goes in other.
 612          */
 613         while (head != NULL) {
 614                 mp = head;
 615                 head = head->b_next;
 616                 mp->b_next = NULL;
 617 
 618                 type = OTH;
 619                 sz1 = (mp->b_cont == NULL) ? MBLKL(mp) : msgdsize(mp);
 620 
 621                 if (is_ether) {
 622                         /*
 623                          * At this point we can be sure the packet at least
 624                          * has an ether header.
 625                          */
 626                         if (sz1 < sizeof (struct ether_header)) {
 627                                 mac_rx_drop_pkt(mac_srs, mp);
 628                                 continue;
 629                         }
 630                         ehp = (struct ether_header *)mp->b_rptr;
 631 
 632                         /*
 633                          * Determine if this is a VLAN or non-VLAN packet.
 634                          */
 635                         if ((sap = ntohs(ehp->ether_type)) == VLAN_TPID) {
 636                                 evhp = (struct ether_vlan_header *)mp->b_rptr;
 637                                 sap = ntohs(evhp->ether_type);
 638                                 hdrsize = sizeof (struct ether_vlan_header);
 639                                 /*
 640                                  * Check if the VID of the packet, if any,
 641                                  * belongs to this client.
 642                                  */
 643                                 if (!mac_client_check_flow_vid(mcip,
 644                                     VLAN_ID(ntohs(evhp->ether_tci)))) {
 645                                         mac_rx_drop_pkt(mac_srs, mp);
 646                                         continue;
 647                                 }
 648                         } else {
 649                                 hdrsize = sizeof (struct ether_header);
 650                         }
 651                         is_unicast =
 652                             ((((uint8_t *)&ehp->ether_dhost)[0] & 0x01) == 0);
 653                         dstaddr = (uint8_t *)&ehp->ether_dhost;
 654                 } else {
 655                         mac_header_info_t               mhi;
 656 
 657                         if (mac_header_info((mac_handle_t)mcip->mci_mip,
 658                             mp, &mhi) != 0) {
 659                                 mac_rx_drop_pkt(mac_srs, mp);
 660                                 continue;
 661                         }
 662                         hdrsize = mhi.mhi_hdrsize;
 663                         sap = mhi.mhi_bindsap;
 664                         is_unicast = (mhi.mhi_dsttype == MAC_ADDRTYPE_UNICAST);
 665                         dstaddr = (uint8_t *)mhi.mhi_daddr;
 666                 }
 667 
 668                 if (!dls_bypass) {
 669                         FANOUT_ENQUEUE_MP(headmp[type], tailmp[type],
 670                             cnt[type], bw_ctl, sz[type], sz1, mp);
 671                         continue;
 672                 }
 673 
 674                 if (sap == ETHERTYPE_IP) {
 675                         /*
 676                          * If we are H/W classified, but we have promisc
 677                          * on, then we need to check for the unicast address.
 678                          */
 679                         if (hw_classified && mcip->mci_promisc_list != NULL) {
 680                                 mac_address_t           *map;
 681 
 682                                 rw_enter(&mcip->mci_rw_lock, RW_READER);
 683                                 map = mcip->mci_unicast;
 684                                 if (bcmp(dstaddr, map->ma_addr,
 685                                     map->ma_len) == 0)
 686                                         type = UNDEF;
 687                                 rw_exit(&mcip->mci_rw_lock);
 688                         } else if (is_unicast) {
 689                                 type = UNDEF;
 690                         }
 691                 }
 692 
 693                 /*
 694                  * This needs to become a contract with the driver for
 695                  * the fast path.
 696                  *
 697                  * In the normal case the packet will have at least the L2
 698                  * header and the IP + Transport header in the same mblk.
 699                  * This is usually the case when the NIC driver sends up
 700                  * the packet. This is also true when the stack generates
 701                  * a packet that is looped back and when the stack uses the
 702                  * fastpath mechanism. The normal case is optimized for
 703                  * performance and may bypass DLS. All other cases go through
 704                  * the 'OTH' type path without DLS bypass.
 705                  */
 706 
 707                 ipha = (ipha_t *)(mp->b_rptr + hdrsize);
 708                 if ((type != OTH) && MBLK_RX_FANOUT_SLOWPATH(mp, ipha))
 709                         type = OTH;
 710 
 711                 if (type == OTH) {
 712                         FANOUT_ENQUEUE_MP(headmp[type], tailmp[type],
 713                             cnt[type], bw_ctl, sz[type], sz1, mp);
 714                         continue;
 715                 }
 716 
 717                 ASSERT(type == UNDEF);
 718                 /*
 719                  * We look for at least 4 bytes past the IP header to get
 720                  * the port information. If we get an IP fragment, we don't
 721                  * have the port information, and we use just the protocol
 722                  * information.
 723                  */
 724                 switch (ipha->ipha_protocol) {
 725                 case IPPROTO_TCP:
 726                         type = V4_TCP;
 727                         mp->b_rptr += hdrsize;
 728                         break;
 729                 case IPPROTO_UDP:
 730                         type = V4_UDP;
 731                         mp->b_rptr += hdrsize;
 732                         break;
 733                 default:
 734                         type = OTH;
 735                         break;
 736                 }
 737 
 738                 FANOUT_ENQUEUE_MP(headmp[type], tailmp[type], cnt[type],
 739                     bw_ctl, sz[type], sz1, mp);
 740         }
 741 
 742         for (type = V4_TCP; type < UNDEF; type++) {
 743                 if (headmp[type] != NULL) {
 744                         mac_soft_ring_t                 *softring;
 745 
 746                         ASSERT(tailmp[type]->b_next == NULL);
 747                         switch (type) {
 748                         case V4_TCP:
 749                                 softring = mac_srs->srs_tcp_soft_rings[0];
 750                                 break;
 751                         case V4_UDP:
 752                                 softring = mac_srs->srs_udp_soft_rings[0];
 753                                 break;
 754                         case OTH:
 755                                 softring = mac_srs->srs_oth_soft_rings[0];
 756                         }
 757                         mac_rx_soft_ring_process(mcip, softring,
 758                             headmp[type], tailmp[type], cnt[type], sz[type]);
 759                 }
 760         }
 761 }
 762 
 763 int     fanout_unaligned = 0;
 764 
 765 /*
 766  * mac_rx_srs_long_fanout
 767  *
 768  * The fanout routine for VLANs, and for anything else that isn't performing
 769  * explicit dls bypass.  Returns -1 on an error (drop the packet due to a
 770  * malformed packet), 0 on success, with values written in *indx and *type.
 771  */
 772 static int
 773 mac_rx_srs_long_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *mp,
 774     uint32_t sap, size_t hdrsize, enum pkt_type *type, uint_t *indx)
 775 {
 776         ip6_t           *ip6h;
 777         ipha_t          *ipha;
 778         uint8_t         *whereptr;
 779         uint_t          hash;
 780         uint16_t        remlen;
 781         uint8_t         nexthdr;
 782         uint16_t        hdr_len;
 783         uint32_t        src_val;
 784         boolean_t       modifiable = B_TRUE;
 785         boolean_t       v6;
 786 
 787         ASSERT(MBLKL(mp) >= hdrsize);
 788 
 789         if (sap == ETHERTYPE_IPV6) {
 790                 v6 = B_TRUE;
 791                 hdr_len = IPV6_HDR_LEN;
 792         } else if (sap == ETHERTYPE_IP) {
 793                 v6 = B_FALSE;
 794                 hdr_len = IP_SIMPLE_HDR_LENGTH;
 795         } else {
 796                 *indx = 0;
 797                 *type = OTH;
 798                 return (0);
 799         }
 800 
 801         ip6h = (ip6_t *)(mp->b_rptr + hdrsize);
 802         ipha = (ipha_t *)ip6h;
 803 
 804         if ((uint8_t *)ip6h == mp->b_wptr) {
 805                 /*
 806                  * The first mblk_t only includes the mac header.
 807                  * Note that it is safe to change the mp pointer here,
 808                  * as the subsequent operation does not assume mp
 809                  * points to the start of the mac header.
 810                  */
 811                 mp = mp->b_cont;
 812 
 813                 /*
 814                  * Make sure the IP header points to an entire one.
 815                  */
 816                 if (mp == NULL)
 817                         return (-1);
 818 
 819                 if (MBLKL(mp) < hdr_len) {
 820                         modifiable = (DB_REF(mp) == 1);
 821 
 822                         if (modifiable && !pullupmsg(mp, hdr_len))
 823                                 return (-1);
 824                 }
 825 
 826                 ip6h = (ip6_t *)mp->b_rptr;
 827                 ipha = (ipha_t *)ip6h;
 828         }
 829 
 830         if (!modifiable || !(OK_32PTR((char *)ip6h)) ||
 831             ((uint8_t *)ip6h + hdr_len > mp->b_wptr)) {
 832                 /*
 833                  * If either the IP header is not aligned, or it does not hold
 834                  * the complete simple structure (a pullupmsg() is not an
 835                  * option since it would result in an unaligned IP header),
 836                  * fanout to the default ring.
 837                  *
 838                  * Note that this may cause packet reordering.
 839                  */
 840                 *indx = 0;
 841                 *type = OTH;
 842                 fanout_unaligned++;
 843                 return (0);
 844         }
 845 
 846         /*
 847          * Extract next-header, full header length, and source-hash value
 848          * using v4/v6 specific fields.
 849          */
 850         if (v6) {
 851                 remlen = ntohs(ip6h->ip6_plen);
 852                 nexthdr = ip6h->ip6_nxt;
 853                 src_val = V4_PART_OF_V6(ip6h->ip6_src);
 854                 /*
 855                  * Do src based fanout if below tunable is set to B_TRUE or
 856                  * when mac_ip_hdr_length_v6() fails because of malformed
 857                  * packets or because mblks need to be concatenated using
 858                  * pullupmsg().
 859                  */
 860                 if (mac_src_ipv6_fanout || !mac_ip_hdr_length_v6(ip6h,
 861                     mp->b_wptr, &hdr_len, &nexthdr, NULL)) {
 862                         goto src_based_fanout;
 863                 }
 864         } else {
 865                 hdr_len = IPH_HDR_LENGTH(ipha);
 866                 remlen = ntohs(ipha->ipha_length) - hdr_len;
 867                 nexthdr = ipha->ipha_protocol;
 868                 src_val = (uint32_t)ipha->ipha_src;
 869                 /*
 870                  * Catch IPv4 fragment case here.  IPv6 has nexthdr == FRAG
 871                  * for its equivalent case.
 872                  */
 873                 if (mac_src_ipv4_fanout ||
 874                     (ntohs(ipha->ipha_fragment_offset_and_flags) &
 875                     (IPH_MF | IPH_OFFSET)) != 0) {
 876                         goto src_based_fanout;
 877                 }
 878         }
 879         if (remlen < MIN_EHDR_LEN)
 880                 return (-1);
 881         whereptr = (uint8_t *)ip6h + hdr_len;
 882 
 883         /* If the transport is one of below, we do port/SPI based fanout */
 884         switch (nexthdr) {
 885         case IPPROTO_TCP:
 886         case IPPROTO_UDP:
 887         case IPPROTO_SCTP:
 888         case IPPROTO_ESP:
 889                 /*
 890                  * If the ports or SPI in the transport header is not part of
 891                  * the mblk, do src_based_fanout, instead of calling
 892                  * pullupmsg().
 893                  */
 894                 if (mp->b_cont == NULL || whereptr + PORTS_SIZE <= mp->b_wptr)
 895                         break;  /* out of switch... */
 896                 /* FALLTHRU */
 897         default:
 898                 goto src_based_fanout;
 899         }
 900 
 901         switch (nexthdr) {
 902         case IPPROTO_TCP:
 903                 hash = HASH_ADDR(src_val, *(uint32_t *)whereptr);
 904                 *indx = COMPUTE_INDEX(hash, mac_srs->srs_tcp_ring_count);
 905                 *type = OTH;
 906                 break;
 907         case IPPROTO_UDP:
 908         case IPPROTO_SCTP:
 909         case IPPROTO_ESP:
 910                 if (mac_fanout_type == MAC_FANOUT_DEFAULT) {
 911                         hash = HASH_ADDR(src_val, *(uint32_t *)whereptr);
 912                         *indx = COMPUTE_INDEX(hash,
 913                             mac_srs->srs_udp_ring_count);
 914                 } else {
 915                         *indx = mac_srs->srs_ind % mac_srs->srs_udp_ring_count;
 916                         mac_srs->srs_ind++;
 917                 }
 918                 *type = OTH;
 919                 break;
 920         }
 921         return (0);
 922 
 923 src_based_fanout:
 924         hash = HASH_ADDR(src_val, (uint32_t)0);
 925         *indx = COMPUTE_INDEX(hash, mac_srs->srs_oth_ring_count);
 926         *type = OTH;
 927         return (0);
 928 }
 929 
 930 /*
 931  * mac_rx_srs_fanout
 932  *
 933  * This routine delivers packets destined to an SRS into a soft ring member
 934  * of the set.
 935  *
 936  * Given a chain of packets we need to split it up into multiple sub chains
 937  * destined for one of the TCP, UDP or OTH soft rings. Instead of entering
 938  * the soft ring one packet at a time, we want to enter it in the form of a
 939  * chain otherwise we get this start/stop behaviour where the worker thread
 940  * goes to sleep and then next packets comes in forcing it to wake up etc.
 941  *
 942  * Note:
 943  * Since we know what is the maximum fanout possible, we create a 2D array
 944  * of 'softring types * MAX_SR_FANOUT' for the head, tail, cnt and sz
 945  * variables so that we can enter the softrings with chain. We need the
 946  * MAX_SR_FANOUT so we can allocate the arrays on the stack (a kmem_alloc
 947  * for each packet would be expensive). If we ever want to have the
 948  * ability to have unlimited fanout, we should probably declare a head,
 949  * tail, cnt, sz with each soft ring (a data struct which contains a softring
 950  * along with these members) and create an array of this uber struct so we
 951  * don't have to do kmem_alloc.
 952  */
 953 int     fanout_oth1 = 0;
 954 int     fanout_oth2 = 0;
 955 int     fanout_oth3 = 0;
 956 int     fanout_oth4 = 0;
 957 int     fanout_oth5 = 0;
 958 
 959 static void
 960 mac_rx_srs_fanout(mac_soft_ring_set_t *mac_srs, mblk_t *head)
 961 {
 962         struct ether_header             *ehp;
 963         struct ether_vlan_header        *evhp;
 964         uint32_t                        sap;
 965         ipha_t                          *ipha;
 966         uint8_t                         *dstaddr;
 967         uint_t                          indx;
 968         size_t                          ports_offset;
 969         size_t                          ipha_len;
 970         size_t                          hdrsize;
 971         uint_t                          hash;
 972         mblk_t                          *mp;
 973         mblk_t                          *headmp[MAX_SR_TYPES][MAX_SR_FANOUT];
 974         mblk_t                          *tailmp[MAX_SR_TYPES][MAX_SR_FANOUT];
 975         int                             cnt[MAX_SR_TYPES][MAX_SR_FANOUT];
 976         size_t                          sz[MAX_SR_TYPES][MAX_SR_FANOUT];
 977         size_t                          sz1;
 978         boolean_t                       bw_ctl;
 979         boolean_t                       hw_classified;
 980         boolean_t                       dls_bypass;
 981         boolean_t                       is_ether;
 982         boolean_t                       is_unicast;
 983         int                             fanout_cnt;
 984         enum pkt_type                   type;
 985         mac_client_impl_t               *mcip = mac_srs->srs_mcip;
 986 
 987         is_ether = (mcip->mci_mip->mi_info.mi_nativemedia == DL_ETHER);
 988         bw_ctl = ((mac_srs->srs_type & SRST_BW_CONTROL) != 0);
 989 
 990         /*
 991          * If we don't have a Rx ring, S/W classification would have done
 992          * its job and its a packet meant for us. If we were polling on
 993          * the default ring (i.e. there was a ring assigned to this SRS),
 994          * then we need to make sure that the mac address really belongs
 995          * to us.
 996          */
 997         hw_classified = mac_srs->srs_ring != NULL &&
 998             mac_srs->srs_ring->mr_classify_type == MAC_HW_CLASSIFIER;
 999 
1000         /*
1001          * Special clients (eg. VLAN, non ether, etc) need DLS
1002          * processing in the Rx path. SRST_DLS_BYPASS will be clear for
1003          * such SRSs. Another way of disabling bypass is to set the
1004          * MCIS_RX_BYPASS_DISABLE flag.
1005          */
1006         dls_bypass = ((mac_srs->srs_type & SRST_DLS_BYPASS) != 0) &&
1007             ((mcip->mci_state_flags & MCIS_RX_BYPASS_DISABLE) == 0);
1008 
1009         /*
1010          * Since the softrings are never destroyed and we always
1011          * create equal number of softrings for TCP, UDP and rest,
1012          * its OK to check one of them for count and use it without
1013          * any lock. In future, if soft rings get destroyed because
1014          * of reduction in fanout, we will need to ensure that happens
1015          * behind the SRS_PROC.
1016          */
1017         fanout_cnt = mac_srs->srs_tcp_ring_count;
1018 
1019         bzero(headmp, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (mblk_t *));
1020         bzero(tailmp, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (mblk_t *));
1021         bzero(cnt, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (int));
1022         bzero(sz, MAX_SR_TYPES * MAX_SR_FANOUT * sizeof (size_t));
1023 
1024         /*
1025          * We got a chain from SRS that we need to send to the soft rings.
1026          * Since squeues for TCP & IPv4 sap poll their soft rings (for
1027          * performance reasons), we need to separate out v4_tcp, v4_udp
1028          * and the rest goes in other.
1029          */
1030         while (head != NULL) {
1031                 mp = head;
1032                 head = head->b_next;
1033                 mp->b_next = NULL;
1034 
1035                 type = OTH;
1036                 sz1 = (mp->b_cont == NULL) ? MBLKL(mp) : msgdsize(mp);
1037 
1038                 if (is_ether) {
1039                         /*
1040                          * At this point we can be sure the packet at least
1041                          * has an ether header.
1042                          */
1043                         if (sz1 < sizeof (struct ether_header)) {
1044                                 mac_rx_drop_pkt(mac_srs, mp);
1045                                 continue;
1046                         }
1047                         ehp = (struct ether_header *)mp->b_rptr;
1048 
1049                         /*
1050                          * Determine if this is a VLAN or non-VLAN packet.
1051                          */
1052                         if ((sap = ntohs(ehp->ether_type)) == VLAN_TPID) {
1053                                 evhp = (struct ether_vlan_header *)mp->b_rptr;
1054                                 sap = ntohs(evhp->ether_type);
1055                                 hdrsize = sizeof (struct ether_vlan_header);
1056                                 /*
1057                                  * Check if the VID of the packet, if any,
1058                                  * belongs to this client.
1059                                  */
1060                                 if (!mac_client_check_flow_vid(mcip,
1061                                     VLAN_ID(ntohs(evhp->ether_tci)))) {
1062                                         mac_rx_drop_pkt(mac_srs, mp);
1063                                         continue;
1064                                 }
1065                         } else {
1066                                 hdrsize = sizeof (struct ether_header);
1067                         }
1068                         is_unicast =
1069                             ((((uint8_t *)&ehp->ether_dhost)[0] & 0x01) == 0);
1070                         dstaddr = (uint8_t *)&ehp->ether_dhost;
1071                 } else {
1072                         mac_header_info_t               mhi;
1073 
1074                         if (mac_header_info((mac_handle_t)mcip->mci_mip,
1075                             mp, &mhi) != 0) {
1076                                 mac_rx_drop_pkt(mac_srs, mp);
1077                                 continue;
1078                         }
1079                         hdrsize = mhi.mhi_hdrsize;
1080                         sap = mhi.mhi_bindsap;
1081                         is_unicast = (mhi.mhi_dsttype == MAC_ADDRTYPE_UNICAST);
1082                         dstaddr = (uint8_t *)mhi.mhi_daddr;
1083                 }
1084 
1085                 if (!dls_bypass) {
1086                         if (mac_rx_srs_long_fanout(mac_srs, mp, sap,
1087                             hdrsize, &type, &indx) == -1) {
1088                                 mac_rx_drop_pkt(mac_srs, mp);
1089                                 continue;
1090                         }
1091 
1092                         FANOUT_ENQUEUE_MP(headmp[type][indx],
1093                             tailmp[type][indx], cnt[type][indx], bw_ctl,
1094                             sz[type][indx], sz1, mp);
1095                         continue;
1096                 }
1097 
1098 
1099                 /*
1100                  * If we are using the default Rx ring where H/W or S/W
1101                  * classification has not happened, we need to verify if
1102                  * this unicast packet really belongs to us.
1103                  */
1104                 if (sap == ETHERTYPE_IP) {
1105                         /*
1106                          * If we are H/W classified, but we have promisc
1107                          * on, then we need to check for the unicast address.
1108                          */
1109                         if (hw_classified && mcip->mci_promisc_list != NULL) {
1110                                 mac_address_t           *map;
1111 
1112                                 rw_enter(&mcip->mci_rw_lock, RW_READER);
1113                                 map = mcip->mci_unicast;
1114                                 if (bcmp(dstaddr, map->ma_addr,
1115                                     map->ma_len) == 0)
1116                                         type = UNDEF;
1117                                 rw_exit(&mcip->mci_rw_lock);
1118                         } else if (is_unicast) {
1119                                 type = UNDEF;
1120                         }
1121                 }
1122 
1123                 /*
1124                  * This needs to become a contract with the driver for
1125                  * the fast path.
1126                  */
1127 
1128                 ipha = (ipha_t *)(mp->b_rptr + hdrsize);
1129                 if ((type != OTH) && MBLK_RX_FANOUT_SLOWPATH(mp, ipha)) {
1130                         type = OTH;
1131                         fanout_oth1++;
1132                 }
1133 
1134                 if (type != OTH) {
1135                         uint16_t        frag_offset_flags;
1136 
1137                         switch (ipha->ipha_protocol) {
1138                         case IPPROTO_TCP:
1139                         case IPPROTO_UDP:
1140                         case IPPROTO_SCTP:
1141                         case IPPROTO_ESP:
1142                                 ipha_len = IPH_HDR_LENGTH(ipha);
1143                                 if ((uchar_t *)ipha + ipha_len + PORTS_SIZE >
1144                                     mp->b_wptr) {
1145                                         type = OTH;
1146                                         break;
1147                                 }
1148                                 frag_offset_flags =
1149                                     ntohs(ipha->ipha_fragment_offset_and_flags);
1150                                 if ((frag_offset_flags &
1151                                     (IPH_MF | IPH_OFFSET)) != 0) {
1152                                         type = OTH;
1153                                         fanout_oth3++;
1154                                         break;
1155                                 }
1156                                 ports_offset = hdrsize + ipha_len;
1157                                 break;
1158                         default:
1159                                 type = OTH;
1160                                 fanout_oth4++;
1161                                 break;
1162                         }
1163                 }
1164 
1165                 if (type == OTH) {
1166                         if (mac_rx_srs_long_fanout(mac_srs, mp, sap,
1167                             hdrsize, &type, &indx) == -1) {
1168                                 mac_rx_drop_pkt(mac_srs, mp);
1169                                 continue;
1170                         }
1171 
1172                         FANOUT_ENQUEUE_MP(headmp[type][indx],
1173                             tailmp[type][indx], cnt[type][indx], bw_ctl,
1174                             sz[type][indx], sz1, mp);
1175                         continue;
1176                 }
1177 
1178                 ASSERT(type == UNDEF);
1179 
1180                 /*
1181                  * XXX-Sunay: We should hold srs_lock since ring_count
1182                  * below can change. But if we are always called from
1183                  * mac_rx_srs_drain and SRS_PROC is set, then we can
1184                  * enforce that ring_count can't be changed i.e.
1185                  * to change fanout type or ring count, the calling
1186                  * thread needs to be behind SRS_PROC.
1187                  */
1188                 switch (ipha->ipha_protocol) {
1189                 case IPPROTO_TCP:
1190                         /*
1191                          * Note that for ESP, we fanout on SPI and it is at the
1192                          * same offset as the 2x16-bit ports. So it is clumped
1193                          * along with TCP, UDP and SCTP.
1194                          */
1195                         hash = HASH_ADDR(ipha->ipha_src,
1196                             *(uint32_t *)(mp->b_rptr + ports_offset));
1197                         indx = COMPUTE_INDEX(hash, mac_srs->srs_tcp_ring_count);
1198                         type = V4_TCP;
1199                         mp->b_rptr += hdrsize;
1200                         break;
1201                 case IPPROTO_UDP:
1202                 case IPPROTO_SCTP:
1203                 case IPPROTO_ESP:
1204                         if (mac_fanout_type == MAC_FANOUT_DEFAULT) {
1205                                 hash = HASH_ADDR(ipha->ipha_src,
1206                                     *(uint32_t *)(mp->b_rptr + ports_offset));
1207                                 indx = COMPUTE_INDEX(hash,
1208                                     mac_srs->srs_udp_ring_count);
1209                         } else {
1210                                 indx = mac_srs->srs_ind %
1211                                     mac_srs->srs_udp_ring_count;
1212                                 mac_srs->srs_ind++;
1213                         }
1214                         type = V4_UDP;
1215                         mp->b_rptr += hdrsize;
1216                         break;
1217                 default:
1218                         indx = 0;
1219                         type = OTH;
1220                 }
1221 
1222                 FANOUT_ENQUEUE_MP(headmp[type][indx], tailmp[type][indx],
1223                     cnt[type][indx], bw_ctl, sz[type][indx], sz1, mp);
1224         }
1225 
1226         for (type = V4_TCP; type < UNDEF; type++) {
1227                 int     i;
1228 
1229                 for (i = 0; i < fanout_cnt; i++) {
1230                         if (headmp[type][i] != NULL) {
1231                                 mac_soft_ring_t *softring;
1232 
1233                                 ASSERT(tailmp[type][i]->b_next == NULL);
1234                                 switch (type) {
1235                                 case V4_TCP:
1236                                         softring =
1237                                             mac_srs->srs_tcp_soft_rings[i];
1238                                         break;
1239                                 case V4_UDP:
1240                                         softring =
1241                                             mac_srs->srs_udp_soft_rings[i];
1242                                         break;
1243                                 case OTH:
1244                                         softring =
1245                                             mac_srs->srs_oth_soft_rings[i];
1246                                         break;
1247                                 }
1248                                 mac_rx_soft_ring_process(mcip,
1249                                     softring, headmp[type][i], tailmp[type][i],
1250                                     cnt[type][i], sz[type][i]);
1251                         }
1252                 }
1253         }
1254 }
1255 
1256 #define SRS_BYTES_TO_PICKUP     150000
1257 ssize_t max_bytes_to_pickup = SRS_BYTES_TO_PICKUP;
1258 
1259 /*
1260  * mac_rx_srs_poll_ring
1261  *
1262  * This SRS Poll thread uses this routine to poll the underlying hardware
1263  * Rx ring to get a chain of packets. It can inline process that chain
1264  * if mac_latency_optimize is set (default) or signal the SRS worker thread
1265  * to do the remaining processing.
1266  *
1267  * Since packets come in the system via interrupt or poll path, we also
1268  * update the stats and deal with promiscous clients here.
1269  */
1270 void
1271 mac_rx_srs_poll_ring(mac_soft_ring_set_t *mac_srs)
1272 {
1273         kmutex_t                *lock = &mac_srs->srs_lock;
1274         kcondvar_t              *async = &mac_srs->srs_cv;
1275         mac_srs_rx_t            *srs_rx = &mac_srs->srs_rx;
1276         mblk_t                  *head, *tail, *mp;
1277         callb_cpr_t             cprinfo;
1278         ssize_t                 bytes_to_pickup;
1279         size_t                  sz;
1280         int                     count;
1281         mac_client_impl_t       *smcip;
1282 
1283         CALLB_CPR_INIT(&cprinfo, lock, callb_generic_cpr, "mac_srs_poll");
1284         mutex_enter(lock);
1285 
1286 start:
1287         for (;;) {
1288                 if (mac_srs->srs_state & SRS_PAUSE)
1289                         goto done;
1290 
1291                 CALLB_CPR_SAFE_BEGIN(&cprinfo);
1292                 cv_wait(async, lock);
1293                 CALLB_CPR_SAFE_END(&cprinfo, lock);
1294 
1295                 if (mac_srs->srs_state & SRS_PAUSE)
1296                         goto done;
1297 
1298 check_again:
1299                 if (mac_srs->srs_type & SRST_BW_CONTROL) {
1300                         /*
1301                          * We pick as many bytes as we are allowed to queue.
1302                          * Its possible that we will exceed the total
1303                          * packets queued in case this SRS is part of the
1304                          * Rx ring group since > 1 poll thread can be pulling
1305                          * upto the max allowed packets at the same time
1306                          * but that should be OK.
1307                          */
1308                         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1309                         bytes_to_pickup =
1310                             mac_srs->srs_bw->mac_bw_drop_threshold -
1311                             mac_srs->srs_bw->mac_bw_sz;
1312                         /*
1313                          * We shouldn't have been signalled if we
1314                          * have 0 or less bytes to pick but since
1315                          * some of the bytes accounting is driver
1316                          * dependant, we do the safety check.
1317                          */
1318                         if (bytes_to_pickup < 0)
1319                                 bytes_to_pickup = 0;
1320                         mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1321                 } else {
1322                         /*
1323                          * ToDO: Need to change the polling API
1324                          * to add a packet count and a flag which
1325                          * tells the driver whether we want packets
1326                          * based on a count, or bytes, or all the
1327                          * packets queued in the driver/HW. This
1328                          * way, we never have to check the limits
1329                          * on poll path. We truly let only as many
1330                          * packets enter the system as we are willing
1331                          * to process or queue.
1332                          *
1333                          * Something along the lines of
1334                          * pkts_to_pickup = mac_soft_ring_max_q_cnt -
1335                          *      mac_srs->srs_poll_pkt_cnt
1336                          */
1337 
1338                         /*
1339                          * Since we are not doing B/W control, pick
1340                          * as many packets as allowed.
1341                          */
1342                         bytes_to_pickup = max_bytes_to_pickup;
1343                 }
1344 
1345                 /* Poll the underlying Hardware */
1346                 mutex_exit(lock);
1347                 head = MAC_HWRING_POLL(mac_srs->srs_ring, (int)bytes_to_pickup);
1348                 mutex_enter(lock);
1349 
1350                 ASSERT((mac_srs->srs_state & SRS_POLL_THR_OWNER) ==
1351                     SRS_POLL_THR_OWNER);
1352 
1353                 mp = tail = head;
1354                 count = 0;
1355                 sz = 0;
1356                 while (mp != NULL) {
1357                         tail = mp;
1358                         sz += msgdsize(mp);
1359                         mp = mp->b_next;
1360                         count++;
1361                 }
1362 
1363                 if (head != NULL) {
1364                         tail->b_next = NULL;
1365                         smcip = mac_srs->srs_mcip;
1366 
1367                         SRS_RX_STAT_UPDATE(mac_srs, pollbytes, sz);
1368                         SRS_RX_STAT_UPDATE(mac_srs, pollcnt, count);
1369 
1370                         /*
1371                          * If there are any promiscuous mode callbacks
1372                          * defined for this MAC client, pass them a copy
1373                          * if appropriate and also update the counters.
1374                          */
1375                         if (smcip != NULL) {
1376                                 if (smcip->mci_mip->mi_promisc_list != NULL) {
1377                                         mutex_exit(lock);
1378                                         mac_promisc_dispatch(smcip->mci_mip,
1379                                             head, NULL);
1380                                         mutex_enter(lock);
1381                                 }
1382                         }
1383                         if (mac_srs->srs_type & SRST_BW_CONTROL) {
1384                                 mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1385                                 mac_srs->srs_bw->mac_bw_polled += sz;
1386                                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1387                         }
1388                         MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, head, tail,
1389                             count, sz);
1390                         if (count <= 10)
1391                                 srs_rx->sr_stat.mrs_chaincntundr10++;
1392                         else if (count > 10 && count <= 50)
1393                                 srs_rx->sr_stat.mrs_chaincnt10to50++;
1394                         else
1395                                 srs_rx->sr_stat.mrs_chaincntover50++;
1396                 }
1397 
1398                 /*
1399                  * We are guaranteed that SRS_PROC will be set if we
1400                  * are here. Also, poll thread gets to run only if
1401                  * the drain was being done by a worker thread although
1402                  * its possible that worker thread is still running
1403                  * and poll thread was sent down to keep the pipeline
1404                  * going instead of doing a complete drain and then
1405                  * trying to poll the NIC.
1406                  *
1407                  * So we need to check SRS_WORKER flag to make sure
1408                  * that the worker thread is not processing the queue
1409                  * in parallel to us. The flags and conditions are
1410                  * protected by the srs_lock to prevent any race. We
1411                  * ensure that we don't drop the srs_lock from now
1412                  * till the end and similarly we don't drop the srs_lock
1413                  * in mac_rx_srs_drain() till similar condition check
1414                  * are complete. The mac_rx_srs_drain() needs to ensure
1415                  * that SRS_WORKER flag remains set as long as its
1416                  * processing the queue.
1417                  */
1418                 if (!(mac_srs->srs_state & SRS_WORKER) &&
1419                     (mac_srs->srs_first != NULL)) {
1420                         /*
1421                          * We have packets to process and worker thread
1422                          * is not running. Check to see if poll thread is
1423                          * allowed to process.
1424                          */
1425                         if (mac_srs->srs_state & SRS_LATENCY_OPT) {
1426                                 mac_srs->srs_drain_func(mac_srs, SRS_POLL_PROC);
1427                                 if (!(mac_srs->srs_state & SRS_PAUSE) &&
1428                                     srs_rx->sr_poll_pkt_cnt <=
1429                                     srs_rx->sr_lowat) {
1430                                         srs_rx->sr_poll_again++;
1431                                         goto check_again;
1432                                 }
1433                                 /*
1434                                  * We are already above low water mark
1435                                  * so stay in the polling mode but no
1436                                  * need to poll. Once we dip below
1437                                  * the polling threshold, the processing
1438                                  * thread (soft ring) will signal us
1439                                  * to poll again (MAC_UPDATE_SRS_COUNT)
1440                                  */
1441                                 srs_rx->sr_poll_drain_no_poll++;
1442                                 mac_srs->srs_state &= ~(SRS_PROC|SRS_GET_PKTS);
1443                                 /*
1444                                  * In B/W control case, its possible
1445                                  * that the backlog built up due to
1446                                  * B/W limit being reached and packets
1447                                  * are queued only in SRS. In this case,
1448                                  * we should schedule worker thread
1449                                  * since no one else will wake us up.
1450                                  */
1451                                 if ((mac_srs->srs_type & SRST_BW_CONTROL) &&
1452                                     (mac_srs->srs_tid == NULL)) {
1453                                         mac_srs->srs_tid =
1454                                             timeout(mac_srs_fire, mac_srs, 1);
1455                                         srs_rx->sr_poll_worker_wakeup++;
1456                                 }
1457                         } else {
1458                                 /*
1459                                  * Wakeup the worker thread for more processing.
1460                                  * We optimize for throughput in this case.
1461                                  */
1462                                 mac_srs->srs_state &= ~(SRS_PROC|SRS_GET_PKTS);
1463                                 MAC_SRS_WORKER_WAKEUP(mac_srs);
1464                                 srs_rx->sr_poll_sig_worker++;
1465                         }
1466                 } else if ((mac_srs->srs_first == NULL) &&
1467                     !(mac_srs->srs_state & SRS_WORKER)) {
1468                         /*
1469                          * There is nothing queued in SRS and
1470                          * no worker thread running. Plus we
1471                          * didn't get anything from the H/W
1472                          * as well (head == NULL);
1473                          */
1474                         ASSERT(head == NULL);
1475                         mac_srs->srs_state &=
1476                             ~(SRS_PROC|SRS_GET_PKTS);
1477 
1478                         /*
1479                          * If we have a packets in soft ring, don't allow
1480                          * more packets to come into this SRS by keeping the
1481                          * interrupts off but not polling the H/W. The
1482                          * poll thread will get signaled as soon as
1483                          * srs_poll_pkt_cnt dips below poll threshold.
1484                          */
1485                         if (srs_rx->sr_poll_pkt_cnt == 0) {
1486                                 srs_rx->sr_poll_intr_enable++;
1487                                 MAC_SRS_POLLING_OFF(mac_srs);
1488                         } else {
1489                                 /*
1490                                  * We know nothing is queued in SRS
1491                                  * since we are here after checking
1492                                  * srs_first is NULL. The backlog
1493                                  * is entirely due to packets queued
1494                                  * in Soft ring which will wake us up
1495                                  * and get the interface out of polling
1496                                  * mode once the backlog dips below
1497                                  * sr_poll_thres.
1498                                  */
1499                                 srs_rx->sr_poll_no_poll++;
1500                         }
1501                 } else {
1502                         /*
1503                          * Worker thread is already running.
1504                          * Nothing much to do. If the polling
1505                          * was enabled, worker thread will deal
1506                          * with that.
1507                          */
1508                         mac_srs->srs_state &= ~SRS_GET_PKTS;
1509                         srs_rx->sr_poll_goto_sleep++;
1510                 }
1511         }
1512 done:
1513         mac_srs->srs_state |= SRS_POLL_THR_QUIESCED;
1514         cv_signal(&mac_srs->srs_async);
1515         /*
1516          * If this is a temporary quiesce then wait for the restart signal
1517          * from the srs worker. Then clear the flags and signal the srs worker
1518          * to ensure a positive handshake and go back to start.
1519          */
1520         while (!(mac_srs->srs_state & (SRS_CONDEMNED | SRS_POLL_THR_RESTART)))
1521                 cv_wait(async, lock);
1522         if (mac_srs->srs_state & SRS_POLL_THR_RESTART) {
1523                 ASSERT(!(mac_srs->srs_state & SRS_CONDEMNED));
1524                 mac_srs->srs_state &=
1525                     ~(SRS_POLL_THR_QUIESCED | SRS_POLL_THR_RESTART);
1526                 cv_signal(&mac_srs->srs_async);
1527                 goto start;
1528         } else {
1529                 mac_srs->srs_state |= SRS_POLL_THR_EXITED;
1530                 cv_signal(&mac_srs->srs_async);
1531                 CALLB_CPR_EXIT(&cprinfo);
1532                 thread_exit();
1533         }
1534 }
1535 
1536 /*
1537  * mac_srs_pick_chain
1538  *
1539  * In Bandwidth control case, checks how many packets can be processed
1540  * and return them in a sub chain.
1541  */
1542 static mblk_t *
1543 mac_srs_pick_chain(mac_soft_ring_set_t *mac_srs, mblk_t **chain_tail,
1544     size_t *chain_sz, int *chain_cnt)
1545 {
1546         mblk_t                  *head = NULL;
1547         mblk_t                  *tail = NULL;
1548         size_t                  sz;
1549         size_t                  tsz = 0;
1550         int                     cnt = 0;
1551         mblk_t                  *mp;
1552 
1553         ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1554         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1555         if (((mac_srs->srs_bw->mac_bw_used + mac_srs->srs_size) <=
1556             mac_srs->srs_bw->mac_bw_limit) ||
1557             (mac_srs->srs_bw->mac_bw_limit == 0)) {
1558                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1559                 head = mac_srs->srs_first;
1560                 mac_srs->srs_first = NULL;
1561                 *chain_tail = mac_srs->srs_last;
1562                 mac_srs->srs_last = NULL;
1563                 *chain_sz = mac_srs->srs_size;
1564                 *chain_cnt = mac_srs->srs_count;
1565                 mac_srs->srs_count = 0;
1566                 mac_srs->srs_size = 0;
1567                 return (head);
1568         }
1569 
1570         /*
1571          * Can't clear the entire backlog.
1572          * Need to find how many packets to pick
1573          */
1574         ASSERT(MUTEX_HELD(&mac_srs->srs_bw->mac_bw_lock));
1575         while ((mp = mac_srs->srs_first) != NULL) {
1576                 sz = msgdsize(mp);
1577                 if ((tsz + sz + mac_srs->srs_bw->mac_bw_used) >
1578                     mac_srs->srs_bw->mac_bw_limit) {
1579                         if (!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED))
1580                                 mac_srs->srs_bw->mac_bw_state |=
1581                                     SRS_BW_ENFORCED;
1582                         break;
1583                 }
1584 
1585                 /*
1586                  * The _size & cnt is  decremented from the softrings
1587                  * when they send up the packet for polling to work
1588                  * properly.
1589                  */
1590                 tsz += sz;
1591                 cnt++;
1592                 mac_srs->srs_count--;
1593                 mac_srs->srs_size -= sz;
1594                 if (tail != NULL)
1595                         tail->b_next = mp;
1596                 else
1597                         head = mp;
1598                 tail = mp;
1599                 mac_srs->srs_first = mac_srs->srs_first->b_next;
1600         }
1601         mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1602         if (mac_srs->srs_first == NULL)
1603                 mac_srs->srs_last = NULL;
1604 
1605         if (tail != NULL)
1606                 tail->b_next = NULL;
1607         *chain_tail = tail;
1608         *chain_cnt = cnt;
1609         *chain_sz = tsz;
1610 
1611         return (head);
1612 }
1613 
1614 /*
1615  * mac_rx_srs_drain
1616  *
1617  * The SRS drain routine. Gets to run to clear the queue. Any thread
1618  * (worker, interrupt, poll) can call this based on processing model.
1619  * The first thing we do is disable interrupts if possible and then
1620  * drain the queue. we also try to poll the underlying hardware if
1621  * there is a dedicated hardware Rx ring assigned to this SRS.
1622  *
1623  * There is a equivalent drain routine in bandwidth control mode
1624  * mac_rx_srs_drain_bw. There is some code duplication between the two
1625  * routines but they are highly performance sensitive and are easier
1626  * to read/debug if they stay separate. Any code changes here might
1627  * also apply to mac_rx_srs_drain_bw as well.
1628  */
1629 void
1630 mac_rx_srs_drain(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
1631 {
1632         mblk_t                  *head;
1633         mblk_t                  *tail;
1634         timeout_id_t            tid;
1635         int                     cnt = 0;
1636         mac_client_impl_t       *mcip = mac_srs->srs_mcip;
1637         mac_srs_rx_t            *srs_rx = &mac_srs->srs_rx;
1638 
1639         ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1640         ASSERT(!(mac_srs->srs_type & SRST_BW_CONTROL));
1641 
1642         /* If we are blanked i.e. can't do upcalls, then we are done */
1643         if (mac_srs->srs_state & (SRS_BLANK | SRS_PAUSE)) {
1644                 ASSERT((mac_srs->srs_type & SRST_NO_SOFT_RINGS) ||
1645                     (mac_srs->srs_state & SRS_PAUSE));
1646                 goto out;
1647         }
1648 
1649         if (mac_srs->srs_first == NULL)
1650                 goto out;
1651 
1652         if (!(mac_srs->srs_state & SRS_LATENCY_OPT) &&
1653             (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat)) {
1654                 /*
1655                  * In the normal case, the SRS worker thread does no
1656                  * work and we wait for a backlog to build up before
1657                  * we switch into polling mode. In case we are
1658                  * optimizing for throughput, we use the worker thread
1659                  * as well. The goal is to let worker thread process
1660                  * the queue and poll thread to feed packets into
1661                  * the queue. As such, we should signal the poll
1662                  * thread to try and get more packets.
1663                  *
1664                  * We could have pulled this check in the POLL_RING
1665                  * macro itself but keeping it explicit here makes
1666                  * the architecture more human understandable.
1667                  */
1668                 MAC_SRS_POLL_RING(mac_srs);
1669         }
1670 
1671 again:
1672         head = mac_srs->srs_first;
1673         mac_srs->srs_first = NULL;
1674         tail = mac_srs->srs_last;
1675         mac_srs->srs_last = NULL;
1676         cnt = mac_srs->srs_count;
1677         mac_srs->srs_count = 0;
1678 
1679         ASSERT(head != NULL);
1680         ASSERT(tail != NULL);
1681 
1682         if ((tid = mac_srs->srs_tid) != 0)
1683                 mac_srs->srs_tid = 0;
1684 
1685         mac_srs->srs_state |= (SRS_PROC|proc_type);
1686 
1687 
1688         /*
1689          * mcip is NULL for broadcast and multicast flows. The promisc
1690          * callbacks for broadcast and multicast packets are delivered from
1691          * mac_rx() and we don't need to worry about that case in this path
1692          */
1693         if (mcip != NULL) {
1694                 if (mcip->mci_promisc_list != NULL) {
1695                         mutex_exit(&mac_srs->srs_lock);
1696                         mac_promisc_client_dispatch(mcip, head);
1697                         mutex_enter(&mac_srs->srs_lock);
1698                 }
1699                 if (MAC_PROTECT_ENABLED(mcip, MPT_IPNOSPOOF)) {
1700                         mutex_exit(&mac_srs->srs_lock);
1701                         mac_protect_intercept_dhcp(mcip, head);
1702                         mutex_enter(&mac_srs->srs_lock);
1703                 }
1704         }
1705 
1706         /*
1707          * Check if SRS itself is doing the processing
1708          * This direct path does not apply when subflows are present. In this
1709          * case, packets need to be dispatched to a soft ring according to the
1710          * flow's bandwidth and other resources contraints.
1711          */
1712         if (mac_srs->srs_type & SRST_NO_SOFT_RINGS) {
1713                 mac_direct_rx_t         proc;
1714                 void                    *arg1;
1715                 mac_resource_handle_t   arg2;
1716 
1717                 /*
1718                  * This is the case when a Rx is directly
1719                  * assigned and we have a fully classified
1720                  * protocol chain. We can deal with it in
1721                  * one shot.
1722                  */
1723                 proc = srs_rx->sr_func;
1724                 arg1 = srs_rx->sr_arg1;
1725                 arg2 = srs_rx->sr_arg2;
1726 
1727                 mac_srs->srs_state |= SRS_CLIENT_PROC;
1728                 mutex_exit(&mac_srs->srs_lock);
1729                 if (tid != 0) {
1730                         (void) untimeout(tid);
1731                         tid = 0;
1732                 }
1733 
1734                 proc(arg1, arg2, head, NULL);
1735                 /*
1736                  * Decrement the size and count here itelf
1737                  * since the packet has been processed.
1738                  */
1739                 mutex_enter(&mac_srs->srs_lock);
1740                 MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
1741                 if (mac_srs->srs_state & SRS_CLIENT_WAIT)
1742                         cv_signal(&mac_srs->srs_client_cv);
1743                 mac_srs->srs_state &= ~SRS_CLIENT_PROC;
1744         } else {
1745                 /* Some kind of softrings based fanout is required */
1746                 mutex_exit(&mac_srs->srs_lock);
1747                 if (tid != 0) {
1748                         (void) untimeout(tid);
1749                         tid = 0;
1750                 }
1751 
1752                 /*
1753                  * Since the fanout routines can deal with chains,
1754                  * shoot the entire chain up.
1755                  */
1756                 if (mac_srs->srs_type & SRST_FANOUT_SRC_IP)
1757                         mac_rx_srs_fanout(mac_srs, head);
1758                 else
1759                         mac_rx_srs_proto_fanout(mac_srs, head);
1760                 mutex_enter(&mac_srs->srs_lock);
1761         }
1762 
1763         if (!(mac_srs->srs_state & (SRS_BLANK|SRS_PAUSE)) &&
1764             (mac_srs->srs_first != NULL)) {
1765                 /*
1766                  * More packets arrived while we were clearing the
1767                  * SRS. This can be possible because of one of
1768                  * three conditions below:
1769                  * 1) The driver is using multiple worker threads
1770                  *    to send the packets to us.
1771                  * 2) The driver has a race in switching
1772                  *    between interrupt and polling mode or
1773                  * 3) Packets are arriving in this SRS via the
1774                  *    S/W classification as well.
1775                  *
1776                  * We should switch to polling mode and see if we
1777                  * need to send the poll thread down. Also, signal
1778                  * the worker thread to process whats just arrived.
1779                  */
1780                 MAC_SRS_POLLING_ON(mac_srs);
1781                 if (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat) {
1782                         srs_rx->sr_drain_poll_sig++;
1783                         MAC_SRS_POLL_RING(mac_srs);
1784                 }
1785 
1786                 /*
1787                  * If we didn't signal the poll thread, we need
1788                  * to deal with the pending packets ourselves.
1789                  */
1790                 if (proc_type == SRS_WORKER) {
1791                         srs_rx->sr_drain_again++;
1792                         goto again;
1793                 } else {
1794                         srs_rx->sr_drain_worker_sig++;
1795                         cv_signal(&mac_srs->srs_async);
1796                 }
1797         }
1798 
1799 out:
1800         if (mac_srs->srs_state & SRS_GET_PKTS) {
1801                 /*
1802                  * Poll thread is already running. Leave the
1803                  * SRS_RPOC set and hand over the control to
1804                  * poll thread.
1805                  */
1806                 mac_srs->srs_state &= ~proc_type;
1807                 srs_rx->sr_drain_poll_running++;
1808                 return;
1809         }
1810 
1811         /*
1812          * Even if there are no packets queued in SRS, we
1813          * need to make sure that the shared counter is
1814          * clear and any associated softrings have cleared
1815          * all the backlog. Otherwise, leave the interface
1816          * in polling mode and the poll thread will get
1817          * signalled once the count goes down to zero.
1818          *
1819          * If someone is already draining the queue (SRS_PROC is
1820          * set) when the srs_poll_pkt_cnt goes down to zero,
1821          * then it means that drain is already running and we
1822          * will turn off polling at that time if there is
1823          * no backlog.
1824          *
1825          * As long as there are packets queued either
1826          * in soft ring set or its soft rings, we will leave
1827          * the interface in polling mode (even if the drain
1828          * was done being the interrupt thread). We signal
1829          * the poll thread as well if we have dipped below
1830          * low water mark.
1831          *
1832          * NOTE: We can't use the MAC_SRS_POLLING_ON macro
1833          * since that turn polling on only for worker thread.
1834          * Its not worth turning polling on for interrupt
1835          * thread (since NIC will not issue another interrupt)
1836          * unless a backlog builds up.
1837          */
1838         if ((srs_rx->sr_poll_pkt_cnt > 0) &&
1839             (mac_srs->srs_state & SRS_POLLING_CAPAB)) {
1840                 mac_srs->srs_state &= ~(SRS_PROC|proc_type);
1841                 srs_rx->sr_drain_keep_polling++;
1842                 MAC_SRS_POLLING_ON(mac_srs);
1843                 if (srs_rx->sr_poll_pkt_cnt <= srs_rx->sr_lowat)
1844                         MAC_SRS_POLL_RING(mac_srs);
1845                 return;
1846         }
1847 
1848         /* Nothing else to do. Get out of poll mode */
1849         MAC_SRS_POLLING_OFF(mac_srs);
1850         mac_srs->srs_state &= ~(SRS_PROC|proc_type);
1851         srs_rx->sr_drain_finish_intr++;
1852 }
1853 
1854 /*
1855  * mac_rx_srs_drain_bw
1856  *
1857  * The SRS BW drain routine. Gets to run to clear the queue. Any thread
1858  * (worker, interrupt, poll) can call this based on processing model.
1859  * The first thing we do is disable interrupts if possible and then
1860  * drain the queue. we also try to poll the underlying hardware if
1861  * there is a dedicated hardware Rx ring assigned to this SRS.
1862  *
1863  * There is a equivalent drain routine in non bandwidth control mode
1864  * mac_rx_srs_drain. There is some code duplication between the two
1865  * routines but they are highly performance sensitive and are easier
1866  * to read/debug if they stay separate. Any code changes here might
1867  * also apply to mac_rx_srs_drain as well.
1868  */
1869 void
1870 mac_rx_srs_drain_bw(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
1871 {
1872         mblk_t                  *head;
1873         mblk_t                  *tail;
1874         timeout_id_t            tid;
1875         size_t                  sz = 0;
1876         int                     cnt = 0;
1877         mac_client_impl_t       *mcip = mac_srs->srs_mcip;
1878         mac_srs_rx_t            *srs_rx = &mac_srs->srs_rx;
1879         clock_t                 now;
1880 
1881         ASSERT(MUTEX_HELD(&mac_srs->srs_lock));
1882         ASSERT(mac_srs->srs_type & SRST_BW_CONTROL);
1883 again:
1884         /* Check if we are doing B/W control */
1885         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1886         now = ddi_get_lbolt();
1887         if (mac_srs->srs_bw->mac_bw_curr_time != now) {
1888                 mac_srs->srs_bw->mac_bw_curr_time = now;
1889                 mac_srs->srs_bw->mac_bw_used = 0;
1890                 if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)
1891                         mac_srs->srs_bw->mac_bw_state &= ~SRS_BW_ENFORCED;
1892         } else if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED) {
1893                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1894                 goto done;
1895         } else if (mac_srs->srs_bw->mac_bw_used >
1896             mac_srs->srs_bw->mac_bw_limit) {
1897                 mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
1898                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1899                 goto done;
1900         }
1901         mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1902 
1903         /* If we are blanked i.e. can't do upcalls, then we are done */
1904         if (mac_srs->srs_state & (SRS_BLANK | SRS_PAUSE)) {
1905                 ASSERT((mac_srs->srs_type & SRST_NO_SOFT_RINGS) ||
1906                     (mac_srs->srs_state & SRS_PAUSE));
1907                 goto done;
1908         }
1909 
1910         sz = 0;
1911         cnt = 0;
1912         if ((head = mac_srs_pick_chain(mac_srs, &tail, &sz, &cnt)) == NULL) {
1913                 /*
1914                  * We couldn't pick up a single packet.
1915                  */
1916                 mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1917                 if ((mac_srs->srs_bw->mac_bw_used == 0) &&
1918                     (mac_srs->srs_size != 0) &&
1919                     !(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
1920                         /*
1921                          * Seems like configured B/W doesn't
1922                          * even allow processing of 1 packet
1923                          * per tick.
1924                          *
1925                          * XXX: raise the limit to processing
1926                          * at least 1 packet per tick.
1927                          */
1928                         mac_srs->srs_bw->mac_bw_limit +=
1929                             mac_srs->srs_bw->mac_bw_limit;
1930                         mac_srs->srs_bw->mac_bw_drop_threshold +=
1931                             mac_srs->srs_bw->mac_bw_drop_threshold;
1932                         cmn_err(CE_NOTE, "mac_rx_srs_drain: srs(%p) "
1933                             "raised B/W limit to %d since not even a "
1934                             "single packet can be processed per "
1935                             "tick %d\n", (void *)mac_srs,
1936                             (int)mac_srs->srs_bw->mac_bw_limit,
1937                             (int)msgdsize(mac_srs->srs_first));
1938                 }
1939                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1940                 goto done;
1941         }
1942 
1943         ASSERT(head != NULL);
1944         ASSERT(tail != NULL);
1945 
1946         /* zero bandwidth: drop all and return to interrupt mode */
1947         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
1948         if (mac_srs->srs_bw->mac_bw_limit == 0) {
1949                 srs_rx->sr_stat.mrs_sdrops += cnt;
1950                 ASSERT(mac_srs->srs_bw->mac_bw_sz >= sz);
1951                 mac_srs->srs_bw->mac_bw_sz -= sz;
1952                 mac_srs->srs_bw->mac_bw_drop_bytes += sz;
1953                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1954                 mac_pkt_drop(NULL, NULL, head, B_FALSE);
1955                 goto leave_poll;
1956         } else {
1957                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
1958         }
1959 
1960         if ((tid = mac_srs->srs_tid) != 0)
1961                 mac_srs->srs_tid = 0;
1962 
1963         mac_srs->srs_state |= (SRS_PROC|proc_type);
1964         MAC_SRS_WORKER_POLLING_ON(mac_srs);
1965 
1966         /*
1967          * mcip is NULL for broadcast and multicast flows. The promisc
1968          * callbacks for broadcast and multicast packets are delivered from
1969          * mac_rx() and we don't need to worry about that case in this path
1970          */
1971         if (mcip != NULL) {
1972                 if (mcip->mci_promisc_list != NULL) {
1973                         mutex_exit(&mac_srs->srs_lock);
1974                         mac_promisc_client_dispatch(mcip, head);
1975                         mutex_enter(&mac_srs->srs_lock);
1976                 }
1977                 if (MAC_PROTECT_ENABLED(mcip, MPT_IPNOSPOOF)) {
1978                         mutex_exit(&mac_srs->srs_lock);
1979                         mac_protect_intercept_dhcp(mcip, head);
1980                         mutex_enter(&mac_srs->srs_lock);
1981                 }
1982         }
1983 
1984         /*
1985          * Check if SRS itself is doing the processing
1986          * This direct path does not apply when subflows are present. In this
1987          * case, packets need to be dispatched to a soft ring according to the
1988          * flow's bandwidth and other resources contraints.
1989          */
1990         if (mac_srs->srs_type & SRST_NO_SOFT_RINGS) {
1991                 mac_direct_rx_t         proc;
1992                 void                    *arg1;
1993                 mac_resource_handle_t   arg2;
1994 
1995                 /*
1996                  * This is the case when a Rx is directly
1997                  * assigned and we have a fully classified
1998                  * protocol chain. We can deal with it in
1999                  * one shot.
2000                  */
2001                 proc = srs_rx->sr_func;
2002                 arg1 = srs_rx->sr_arg1;
2003                 arg2 = srs_rx->sr_arg2;
2004 
2005                 mac_srs->srs_state |= SRS_CLIENT_PROC;
2006                 mutex_exit(&mac_srs->srs_lock);
2007                 if (tid != 0) {
2008                         (void) untimeout(tid);
2009                         tid = 0;
2010                 }
2011 
2012                 proc(arg1, arg2, head, NULL);
2013                 /*
2014                  * Decrement the size and count here itelf
2015                  * since the packet has been processed.
2016                  */
2017                 mutex_enter(&mac_srs->srs_lock);
2018                 MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
2019                 MAC_UPDATE_SRS_SIZE_LOCKED(mac_srs, sz);
2020 
2021                 if (mac_srs->srs_state & SRS_CLIENT_WAIT)
2022                         cv_signal(&mac_srs->srs_client_cv);
2023                 mac_srs->srs_state &= ~SRS_CLIENT_PROC;
2024         } else {
2025                 /* Some kind of softrings based fanout is required */
2026                 mutex_exit(&mac_srs->srs_lock);
2027                 if (tid != 0) {
2028                         (void) untimeout(tid);
2029                         tid = 0;
2030                 }
2031 
2032                 /*
2033                  * Since the fanout routines can deal with chains,
2034                  * shoot the entire chain up.
2035                  */
2036                 if (mac_srs->srs_type & SRST_FANOUT_SRC_IP)
2037                         mac_rx_srs_fanout(mac_srs, head);
2038                 else
2039                         mac_rx_srs_proto_fanout(mac_srs, head);
2040                 mutex_enter(&mac_srs->srs_lock);
2041         }
2042 
2043         /*
2044          * Send the poll thread to pick up any packets arrived
2045          * so far. This also serves as the last check in case
2046          * nothing else is queued in the SRS. The poll thread
2047          * is signalled only in the case the drain was done
2048          * by the worker thread and SRS_WORKER is set. The
2049          * worker thread can run in parallel as long as the
2050          * SRS_WORKER flag is set. We we have nothing else to
2051          * process, we can exit while leaving SRS_PROC set
2052          * which gives the poll thread control to process and
2053          * cleanup once it returns from the NIC.
2054          *
2055          * If we have nothing else to process, we need to
2056          * ensure that we keep holding the srs_lock till
2057          * all the checks below are done and control is
2058          * handed to the poll thread if it was running.
2059          */
2060         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
2061         if (!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
2062                 if (mac_srs->srs_first != NULL) {
2063                         if (proc_type == SRS_WORKER) {
2064                                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2065                                 if (srs_rx->sr_poll_pkt_cnt <=
2066                                     srs_rx->sr_lowat)
2067                                         MAC_SRS_POLL_RING(mac_srs);
2068                                 goto again;
2069                         } else {
2070                                 cv_signal(&mac_srs->srs_async);
2071                         }
2072                 }
2073         }
2074         mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2075 
2076 done:
2077 
2078         if (mac_srs->srs_state & SRS_GET_PKTS) {
2079                 /*
2080                  * Poll thread is already running. Leave the
2081                  * SRS_RPOC set and hand over the control to
2082                  * poll thread.
2083                  */
2084                 mac_srs->srs_state &= ~proc_type;
2085                 return;
2086         }
2087 
2088         /*
2089          * If we can't process packets because we have exceeded
2090          * B/W limit for this tick, just set the timeout
2091          * and leave.
2092          *
2093          * Even if there are no packets queued in SRS, we
2094          * need to make sure that the shared counter is
2095          * clear and any associated softrings have cleared
2096          * all the backlog. Otherwise, leave the interface
2097          * in polling mode and the poll thread will get
2098          * signalled once the count goes down to zero.
2099          *
2100          * If someone is already draining the queue (SRS_PROC is
2101          * set) when the srs_poll_pkt_cnt goes down to zero,
2102          * then it means that drain is already running and we
2103          * will turn off polling at that time if there is
2104          * no backlog. As long as there are packets queued either
2105          * is soft ring set or its soft rings, we will leave
2106          * the interface in polling mode.
2107          */
2108         mutex_enter(&mac_srs->srs_bw->mac_bw_lock);
2109         if ((mac_srs->srs_state & SRS_POLLING_CAPAB) &&
2110             ((mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED) ||
2111             (srs_rx->sr_poll_pkt_cnt > 0))) {
2112                 MAC_SRS_POLLING_ON(mac_srs);
2113                 mac_srs->srs_state &= ~(SRS_PROC|proc_type);
2114                 if ((mac_srs->srs_first != NULL) &&
2115                     (mac_srs->srs_tid == NULL))
2116                         mac_srs->srs_tid = timeout(mac_srs_fire,
2117                             mac_srs, 1);
2118                 mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2119                 return;
2120         }
2121         mutex_exit(&mac_srs->srs_bw->mac_bw_lock);
2122 
2123 leave_poll:
2124 
2125         /* Nothing else to do. Get out of poll mode */
2126         MAC_SRS_POLLING_OFF(mac_srs);
2127         mac_srs->srs_state &= ~(SRS_PROC|proc_type);
2128 }
2129 
2130 /*
2131  * mac_srs_worker
2132  *
2133  * The SRS worker routine. Drains the queue when no one else is
2134  * processing it.
2135  */
2136 void
2137 mac_srs_worker(mac_soft_ring_set_t *mac_srs)
2138 {
2139         kmutex_t                *lock = &mac_srs->srs_lock;
2140         kcondvar_t              *async = &mac_srs->srs_async;
2141         callb_cpr_t             cprinfo;
2142         boolean_t               bw_ctl_flag;
2143 
2144         CALLB_CPR_INIT(&cprinfo, lock, callb_generic_cpr, "srs_worker");
2145         mutex_enter(lock);
2146 
2147 start:
2148         for (;;) {
2149                 bw_ctl_flag = B_FALSE;
2150                 if (mac_srs->srs_type & SRST_BW_CONTROL) {
2151                         MAC_SRS_BW_LOCK(mac_srs);
2152                         MAC_SRS_CHECK_BW_CONTROL(mac_srs);
2153                         if (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)
2154                                 bw_ctl_flag = B_TRUE;
2155                         MAC_SRS_BW_UNLOCK(mac_srs);
2156                 }
2157                 /*
2158                  * The SRS_BW_ENFORCED flag may change since we have dropped
2159                  * the mac_bw_lock. However the drain function can handle both
2160                  * a drainable SRS or a bandwidth controlled SRS, and the
2161                  * effect of scheduling a timeout is to wakeup the worker
2162                  * thread which in turn will call the drain function. Since
2163                  * we release the srs_lock atomically only in the cv_wait there
2164                  * isn't a fear of waiting for ever.
2165                  */
2166                 while (((mac_srs->srs_state & SRS_PROC) ||
2167                     (mac_srs->srs_first == NULL) || bw_ctl_flag ||
2168                     (mac_srs->srs_state & SRS_TX_BLOCKED)) &&
2169                     !(mac_srs->srs_state & SRS_PAUSE)) {
2170                         /*
2171                          * If we have packets queued and we are here
2172                          * because B/W control is in place, we better
2173                          * schedule the worker wakeup after 1 tick
2174                          * to see if bandwidth control can be relaxed.
2175                          */
2176                         if (bw_ctl_flag && mac_srs->srs_tid == NULL) {
2177                                 /*
2178                                  * We need to ensure that a timer  is already
2179                                  * scheduled or we force  schedule one for
2180                                  * later so that we can continue processing
2181                                  * after this  quanta is over.
2182                                  */
2183                                 mac_srs->srs_tid = timeout(mac_srs_fire,
2184                                     mac_srs, 1);
2185                         }
2186 wait:
2187                         CALLB_CPR_SAFE_BEGIN(&cprinfo);
2188                         cv_wait(async, lock);
2189                         CALLB_CPR_SAFE_END(&cprinfo, lock);
2190 
2191                         if (mac_srs->srs_state & SRS_PAUSE)
2192                                 goto done;
2193                         if (mac_srs->srs_state & SRS_PROC)
2194                                 goto wait;
2195 
2196                         if (mac_srs->srs_first != NULL &&
2197                             mac_srs->srs_type & SRST_BW_CONTROL) {
2198                                 MAC_SRS_BW_LOCK(mac_srs);
2199                                 if (mac_srs->srs_bw->mac_bw_state &
2200                                     SRS_BW_ENFORCED) {
2201                                         MAC_SRS_CHECK_BW_CONTROL(mac_srs);
2202                                 }
2203                                 bw_ctl_flag = mac_srs->srs_bw->mac_bw_state &
2204                                     SRS_BW_ENFORCED;
2205                                 MAC_SRS_BW_UNLOCK(mac_srs);
2206                         }
2207                 }
2208 
2209                 if (mac_srs->srs_state & SRS_PAUSE)
2210                         goto done;
2211                 mac_srs->srs_drain_func(mac_srs, SRS_WORKER);
2212         }
2213 done:
2214         /*
2215          * The Rx SRS quiesce logic first cuts off packet supply to the SRS
2216          * from both hard and soft classifications and waits for such threads
2217          * to finish before signaling the worker. So at this point the only
2218          * thread left that could be competing with the worker is the poll
2219          * thread. In the case of Tx, there shouldn't be any thread holding
2220          * SRS_PROC at this point.
2221          */
2222         if (!(mac_srs->srs_state & SRS_PROC)) {
2223                 mac_srs->srs_state |= SRS_PROC;
2224         } else {
2225                 ASSERT((mac_srs->srs_type & SRST_TX) == 0);
2226                 /*
2227                  * Poll thread still owns the SRS and is still running
2228                  */
2229                 ASSERT((mac_srs->srs_poll_thr == NULL) ||
2230                     ((mac_srs->srs_state & SRS_POLL_THR_OWNER) ==
2231                     SRS_POLL_THR_OWNER));
2232         }
2233         mac_srs_worker_quiesce(mac_srs);
2234         /*
2235          * Wait for the SRS_RESTART or SRS_CONDEMNED signal from the initiator
2236          * of the quiesce operation
2237          */
2238         while (!(mac_srs->srs_state & (SRS_CONDEMNED | SRS_RESTART)))
2239                 cv_wait(&mac_srs->srs_async, &mac_srs->srs_lock);
2240 
2241         if (mac_srs->srs_state & SRS_RESTART) {
2242                 ASSERT(!(mac_srs->srs_state & SRS_CONDEMNED));
2243                 mac_srs_worker_restart(mac_srs);
2244                 mac_srs->srs_state &= ~SRS_PROC;
2245                 goto start;
2246         }
2247 
2248         if (!(mac_srs->srs_state & SRS_CONDEMNED_DONE))
2249                 mac_srs_worker_quiesce(mac_srs);
2250 
2251         mac_srs->srs_state &= ~SRS_PROC;
2252         /* The macro drops the srs_lock */
2253         CALLB_CPR_EXIT(&cprinfo);
2254         thread_exit();
2255 }
2256 
2257 /*
2258  * mac_rx_srs_subflow_process
2259  *
2260  * Receive side routine called from interrupt path when there are
2261  * sub flows present on this SRS.
2262  */
2263 /* ARGSUSED */
2264 void
2265 mac_rx_srs_subflow_process(void *arg, mac_resource_handle_t srs,
2266     mblk_t *mp_chain, boolean_t loopback)
2267 {
2268         flow_entry_t            *flent = NULL;
2269         flow_entry_t            *prev_flent = NULL;
2270         mblk_t                  *mp = NULL;
2271         mblk_t                  *tail = NULL;
2272         mac_soft_ring_set_t     *mac_srs = (mac_soft_ring_set_t *)srs;
2273         mac_client_impl_t       *mcip;
2274 
2275         mcip = mac_srs->srs_mcip;
2276         ASSERT(mcip != NULL);
2277 
2278         /*
2279          * We need to determine the SRS for every packet
2280          * by walking the flow table, if we don't get any,
2281          * then we proceed using the SRS we came with.
2282          */
2283         mp = tail = mp_chain;
2284         while (mp != NULL) {
2285 
2286                 /*
2287                  * We will increment the stats for the mactching subflow.
2288                  * when we get the bytes/pkt count for the classified packets
2289                  * later in mac_rx_srs_process.
2290                  */
2291                 (void) mac_flow_lookup(mcip->mci_subflow_tab, mp,
2292                     FLOW_INBOUND, &flent);
2293 
2294                 if (mp == mp_chain || flent == prev_flent) {
2295                         if (prev_flent != NULL)
2296                                 FLOW_REFRELE(prev_flent);
2297                         prev_flent = flent;
2298                         flent = NULL;
2299                         tail = mp;
2300                         mp = mp->b_next;
2301                         continue;
2302                 }
2303                 tail->b_next = NULL;
2304                 /*
2305                  * A null indicates, this is for the mac_srs itself.
2306                  * XXX-venu : probably assert for fe_rx_srs_cnt == 0.
2307                  */
2308                 if (prev_flent == NULL || prev_flent->fe_rx_srs_cnt == 0) {
2309                         mac_rx_srs_process(arg,
2310                             (mac_resource_handle_t)mac_srs, mp_chain,
2311                             loopback);
2312                 } else {
2313                         (prev_flent->fe_cb_fn)(prev_flent->fe_cb_arg1,
2314                             prev_flent->fe_cb_arg2, mp_chain, loopback);
2315                         FLOW_REFRELE(prev_flent);
2316                 }
2317                 prev_flent = flent;
2318                 flent = NULL;
2319                 mp_chain = mp;
2320                 tail = mp;
2321                 mp = mp->b_next;
2322         }
2323         /* Last chain */
2324         ASSERT(mp_chain != NULL);
2325         if (prev_flent == NULL || prev_flent->fe_rx_srs_cnt == 0) {
2326                 mac_rx_srs_process(arg,
2327                     (mac_resource_handle_t)mac_srs, mp_chain, loopback);
2328         } else {
2329                 (prev_flent->fe_cb_fn)(prev_flent->fe_cb_arg1,
2330                     prev_flent->fe_cb_arg2, mp_chain, loopback);
2331                 FLOW_REFRELE(prev_flent);
2332         }
2333 }
2334 
2335 /*
2336  * mac_rx_srs_process
2337  *
2338  * Receive side routine called from the interrupt path.
2339  *
2340  * loopback is set to force a context switch on the loopback
2341  * path between MAC clients.
2342  */
2343 /* ARGSUSED */
2344 void
2345 mac_rx_srs_process(void *arg, mac_resource_handle_t srs, mblk_t *mp_chain,
2346     boolean_t loopback)
2347 {
2348         mac_soft_ring_set_t     *mac_srs = (mac_soft_ring_set_t *)srs;
2349         mblk_t                  *mp, *tail, *head;
2350         int                     count = 0;
2351         int                     count1;
2352         size_t                  sz = 0;
2353         size_t                  chain_sz, sz1;
2354         mac_bw_ctl_t            *mac_bw;
2355         mac_srs_rx_t            *srs_rx = &mac_srs->srs_rx;
2356 
2357         /*
2358          * Set the tail, count and sz. We set the sz irrespective
2359          * of whether we are doing B/W control or not for the
2360          * purpose of updating the stats.
2361          */
2362         mp = tail = mp_chain;
2363         while (mp != NULL) {
2364                 tail = mp;
2365                 count++;
2366                 sz += msgdsize(mp);
2367                 mp = mp->b_next;
2368         }
2369 
2370         mutex_enter(&mac_srs->srs_lock);
2371 
2372         if (loopback) {
2373                 SRS_RX_STAT_UPDATE(mac_srs, lclbytes, sz);
2374                 SRS_RX_STAT_UPDATE(mac_srs, lclcnt, count);
2375 
2376         } else {
2377                 SRS_RX_STAT_UPDATE(mac_srs, intrbytes, sz);
2378                 SRS_RX_STAT_UPDATE(mac_srs, intrcnt, count);
2379         }
2380 
2381         /*
2382          * If the SRS in already being processed; has been blanked;
2383          * can be processed by worker thread only; or the B/W limit
2384          * has been reached, then queue the chain and check if
2385          * worker thread needs to be awakend.
2386          */
2387         if (mac_srs->srs_type & SRST_BW_CONTROL) {
2388                 mac_bw = mac_srs->srs_bw;
2389                 ASSERT(mac_bw != NULL);
2390                 mutex_enter(&mac_bw->mac_bw_lock);
2391                 mac_bw->mac_bw_intr += sz;
2392                 if (mac_bw->mac_bw_limit == 0) {
2393                         /* zero bandwidth: drop all */
2394                         srs_rx->sr_stat.mrs_sdrops += count;
2395                         mac_bw->mac_bw_drop_bytes += sz;
2396                         mutex_exit(&mac_bw->mac_bw_lock);
2397                         mutex_exit(&mac_srs->srs_lock);
2398                         mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);
2399                         return;
2400                 } else {
2401                         if ((mac_bw->mac_bw_sz + sz) <=
2402                             mac_bw->mac_bw_drop_threshold) {
2403                                 mutex_exit(&mac_bw->mac_bw_lock);
2404                                 MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, mp_chain,
2405                                     tail, count, sz);
2406                         } else {
2407                                 mp = mp_chain;
2408                                 chain_sz = 0;
2409                                 count1 = 0;
2410                                 tail = NULL;
2411                                 head = NULL;
2412                                 while (mp != NULL) {
2413                                         sz1 = msgdsize(mp);
2414                                         if (mac_bw->mac_bw_sz + chain_sz + sz1 >
2415                                             mac_bw->mac_bw_drop_threshold)
2416                                                 break;
2417                                         chain_sz += sz1;
2418                                         count1++;
2419                                         tail = mp;
2420                                         mp = mp->b_next;
2421                                 }
2422                                 mutex_exit(&mac_bw->mac_bw_lock);
2423                                 if (tail != NULL) {
2424                                         head = tail->b_next;
2425                                         tail->b_next = NULL;
2426                                         MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs,
2427                                             mp_chain, tail, count1, chain_sz);
2428                                         sz -= chain_sz;
2429                                         count -= count1;
2430                                 } else {
2431                                         /* Can't pick up any */
2432                                         head = mp_chain;
2433                                 }
2434                                 if (head != NULL) {
2435                                         /* Drop any packet over the threshold */
2436                                         srs_rx->sr_stat.mrs_sdrops += count;
2437                                         mutex_enter(&mac_bw->mac_bw_lock);
2438                                         mac_bw->mac_bw_drop_bytes += sz;
2439                                         mutex_exit(&mac_bw->mac_bw_lock);
2440                                         freemsgchain(head);
2441                                 }
2442                         }
2443                         MAC_SRS_WORKER_WAKEUP(mac_srs);
2444                         mutex_exit(&mac_srs->srs_lock);
2445                         return;
2446                 }
2447         }
2448 
2449         /*
2450          * If the total number of packets queued in the SRS and
2451          * its associated soft rings exceeds the max allowed,
2452          * then drop the chain. If we are polling capable, this
2453          * shouldn't be happening.
2454          */
2455         if (!(mac_srs->srs_type & SRST_BW_CONTROL) &&
2456             (srs_rx->sr_poll_pkt_cnt > srs_rx->sr_hiwat)) {
2457                 mac_bw = mac_srs->srs_bw;
2458                 srs_rx->sr_stat.mrs_sdrops += count;
2459                 mutex_enter(&mac_bw->mac_bw_lock);
2460                 mac_bw->mac_bw_drop_bytes += sz;
2461                 mutex_exit(&mac_bw->mac_bw_lock);
2462                 freemsgchain(mp_chain);
2463                 mutex_exit(&mac_srs->srs_lock);
2464                 return;
2465         }
2466 
2467         MAC_RX_SRS_ENQUEUE_CHAIN(mac_srs, mp_chain, tail, count, sz);
2468 
2469         if (!(mac_srs->srs_state & SRS_PROC)) {
2470                 /*
2471                  * If we are coming via loopback, if we are not optimizing for
2472                  * latency, or if our stack is running deep, we should signal
2473                  * the worker thread.
2474                  */
2475                 if (loopback || !(mac_srs->srs_state & SRS_LATENCY_OPT) ||
2476                     MAC_RX_SRS_TOODEEP()) {
2477                         /*
2478                          * For loopback, We need to let the worker take
2479                          * over as we don't want to continue in the same
2480                          * thread even if we can. This could lead to stack
2481                          * overflows and may also end up using
2482                          * resources (cpu) incorrectly.
2483                          */
2484                         cv_signal(&mac_srs->srs_async);
2485                 } else {
2486                         /*
2487                          * Seems like no one is processing the SRS and
2488                          * there is no backlog. We also inline process
2489                          * our packet if its a single packet in non
2490                          * latency optimized case (in latency optimized
2491                          * case, we inline process chains of any size).
2492                          */
2493                         mac_srs->srs_drain_func(mac_srs, SRS_PROC_FAST);
2494                 }
2495         }
2496         mutex_exit(&mac_srs->srs_lock);
2497 }
2498 
2499 /* TX SIDE ROUTINES (RUNTIME) */
2500 
2501 /*
2502  * mac_tx_srs_no_desc
2503  *
2504  * This routine is called by Tx single ring default mode
2505  * when Tx ring runs out of descs.
2506  */
2507 mac_tx_cookie_t
2508 mac_tx_srs_no_desc(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2509     uint16_t flag, mblk_t **ret_mp)
2510 {
2511         mac_tx_cookie_t cookie = NULL;
2512         mac_srs_tx_t *srs_tx = &mac_srs->srs_tx;
2513         boolean_t wakeup_worker = B_TRUE;
2514         uint32_t tx_mode = srs_tx->st_mode;
2515         int cnt, sz;
2516         mblk_t *tail;
2517 
2518         ASSERT(tx_mode == SRS_TX_DEFAULT || tx_mode == SRS_TX_BW);
2519         if (flag & MAC_DROP_ON_NO_DESC) {
2520                 MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2521         } else {
2522                 if (mac_srs->srs_first != NULL)
2523                         wakeup_worker = B_FALSE;
2524                 MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2525                 if (flag & MAC_TX_NO_ENQUEUE) {
2526                         /*
2527                          * If TX_QUEUED is not set, queue the
2528                          * packet and let mac_tx_srs_drain()
2529                          * set the TX_BLOCKED bit for the
2530                          * reasons explained above. Otherwise,
2531                          * return the mblks.
2532                          */
2533                         if (wakeup_worker) {
2534                                 MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2535                                     mp_chain, tail, cnt, sz);
2536                         } else {
2537                                 MAC_TX_SET_NO_ENQUEUE(mac_srs,
2538                                     mp_chain, ret_mp, cookie);
2539                         }
2540                 } else {
2541                         MAC_TX_SRS_TEST_HIWAT(mac_srs, mp_chain,
2542                             tail, cnt, sz, cookie);
2543                 }
2544                 if (wakeup_worker)
2545                         cv_signal(&mac_srs->srs_async);
2546         }
2547         return (cookie);
2548 }
2549 
2550 /*
2551  * mac_tx_srs_enqueue
2552  *
2553  * This routine is called when Tx SRS is operating in either serializer
2554  * or bandwidth mode. In serializer mode, a packet will get enqueued
2555  * when a thread cannot enter SRS exclusively. In bandwidth mode,
2556  * packets gets queued if allowed byte-count limit for a tick is
2557  * exceeded. The action that gets taken when MAC_DROP_ON_NO_DESC and
2558  * MAC_TX_NO_ENQUEUE is set is different than when operaing in either
2559  * the default mode or fanout mode. Here packets get dropped or
2560  * returned back to the caller only after hi-watermark worth of data
2561  * is queued.
2562  */
2563 static mac_tx_cookie_t
2564 mac_tx_srs_enqueue(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2565     uint16_t flag, uintptr_t fanout_hint, mblk_t **ret_mp)
2566 {
2567         mac_tx_cookie_t cookie = NULL;
2568         int cnt, sz;
2569         mblk_t *tail;
2570         boolean_t wakeup_worker = B_TRUE;
2571 
2572         /*
2573          * Ignore fanout hint if we don't have multiple tx rings.
2574          */
2575         if (!MAC_TX_SOFT_RINGS(mac_srs))
2576                 fanout_hint = 0;
2577 
2578         if (mac_srs->srs_first != NULL)
2579                 wakeup_worker = B_FALSE;
2580         MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2581         if (flag & MAC_DROP_ON_NO_DESC) {
2582                 if (mac_srs->srs_count > mac_srs->srs_tx.st_hiwat) {
2583                         MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2584                 } else {
2585                         MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2586                             mp_chain, tail, cnt, sz);
2587                 }
2588         } else if (flag & MAC_TX_NO_ENQUEUE) {
2589                 if ((mac_srs->srs_count > mac_srs->srs_tx.st_hiwat) ||
2590                     (mac_srs->srs_state & SRS_TX_WAKEUP_CLIENT)) {
2591                         MAC_TX_SET_NO_ENQUEUE(mac_srs, mp_chain,
2592                             ret_mp, cookie);
2593                 } else {
2594                         mp_chain->b_prev = (mblk_t *)fanout_hint;
2595                         MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2596                             mp_chain, tail, cnt, sz);
2597                 }
2598         } else {
2599                 /*
2600                  * If you are BW_ENFORCED, just enqueue the
2601                  * packet. srs_worker will drain it at the
2602                  * prescribed rate. Before enqueueing, save
2603                  * the fanout hint.
2604                  */
2605                 mp_chain->b_prev = (mblk_t *)fanout_hint;
2606                 MAC_TX_SRS_TEST_HIWAT(mac_srs, mp_chain,
2607                     tail, cnt, sz, cookie);
2608         }
2609         if (wakeup_worker)
2610                 cv_signal(&mac_srs->srs_async);
2611         return (cookie);
2612 }
2613 
2614 /*
2615  * There are seven tx modes:
2616  *
2617  * 1) Default mode (SRS_TX_DEFAULT)
2618  * 2) Serialization mode (SRS_TX_SERIALIZE)
2619  * 3) Fanout mode (SRS_TX_FANOUT)
2620  * 4) Bandwdith mode (SRS_TX_BW)
2621  * 5) Fanout and Bandwidth mode (SRS_TX_BW_FANOUT)
2622  * 6) aggr Tx mode (SRS_TX_AGGR)
2623  * 7) aggr Tx bw mode (SRS_TX_BW_AGGR)
2624  *
2625  * The tx mode in which an SRS operates is decided in mac_tx_srs_setup()
2626  * based on the number of Tx rings requested for an SRS and whether
2627  * bandwidth control is requested or not.
2628  *
2629  * The default mode (i.e., no fanout/no bandwidth) is used when the
2630  * underlying NIC does not have Tx rings or just one Tx ring. In this mode,
2631  * the SRS acts as a pass-thru. Packets will go directly to mac_tx_send().
2632  * When the underlying Tx ring runs out of Tx descs, it starts queueing up
2633  * packets in SRS. When flow-control is relieved, the srs_worker drains
2634  * the queued packets and informs blocked clients to restart sending
2635  * packets.
2636  *
2637  * In the SRS_TX_SERIALIZE mode, all calls to mac_tx() are serialized. This
2638  * mode is used when the link has no Tx rings or only one Tx ring.
2639  *
2640  * In the SRS_TX_FANOUT mode, packets will be fanned out to multiple
2641  * Tx rings. Each Tx ring will have a soft ring associated with it.
2642  * These soft rings will be hung off the Tx SRS. Queueing if it happens
2643  * due to lack of Tx desc will be in individual soft ring (and not srs)
2644  * associated with Tx ring.
2645  *
2646  * In the TX_BW mode, tx srs will allow packets to go down to Tx ring
2647  * only if bw is available. Otherwise the packets will be queued in
2648  * SRS. If fanout to multiple Tx rings is configured, the packets will
2649  * be fanned out among the soft rings associated with the Tx rings.
2650  *
2651  * In SRS_TX_AGGR mode, mac_tx_aggr_mode() routine is called. This routine
2652  * invokes an aggr function, aggr_find_tx_ring(), to find a pseudo Tx ring
2653  * belonging to a port on which the packet has to be sent. Aggr will
2654  * always have a pseudo Tx ring associated with it even when it is an
2655  * aggregation over a single NIC that has no Tx rings. Even in such a
2656  * case, the single pseudo Tx ring will have a soft ring associated with
2657  * it and the soft ring will hang off the SRS.
2658  *
2659  * If a bandwidth is specified for an aggr, SRS_TX_BW_AGGR mode is used.
2660  * In this mode, the bandwidth is first applied on the outgoing packets
2661  * and later mac_tx_addr_mode() function is called to send the packet out
2662  * of one of the pseudo Tx rings.
2663  *
2664  * Four flags are used in srs_state for indicating flow control
2665  * conditions : SRS_TX_BLOCKED, SRS_TX_HIWAT, SRS_TX_WAKEUP_CLIENT.
2666  * SRS_TX_BLOCKED indicates out of Tx descs. SRS expects a wakeup from the
2667  * driver below.
2668  * SRS_TX_HIWAT indicates packet count enqueued in Tx SRS exceeded Tx hiwat
2669  * and flow-control pressure is applied back to clients. The clients expect
2670  * wakeup when flow-control is relieved.
2671  * SRS_TX_WAKEUP_CLIENT get set when (flag == MAC_TX_NO_ENQUEUE) and mblk
2672  * got returned back to client either due to lack of Tx descs or due to bw
2673  * control reasons. The clients expect a wakeup when condition is relieved.
2674  *
2675  * The fourth argument to mac_tx() is the flag. Normally it will be 0 but
2676  * some clients set the following values too: MAC_DROP_ON_NO_DESC,
2677  * MAC_TX_NO_ENQUEUE
2678  * Mac clients that do not want packets to be enqueued in the mac layer set
2679  * MAC_DROP_ON_NO_DESC value. The packets won't be queued in the Tx SRS or
2680  * Tx soft rings but instead get dropped when the NIC runs out of desc. The
2681  * behaviour of this flag is different when the Tx is running in serializer
2682  * or bandwidth mode. Under these (Serializer, bandwidth) modes, the packet
2683  * get dropped when Tx high watermark is reached.
2684  * There are some mac clients like vsw, aggr that want the mblks to be
2685  * returned back to clients instead of being queued in Tx SRS (or Tx soft
2686  * rings) under flow-control (i.e., out of desc or exceeding bw limits)
2687  * conditions. These clients call mac_tx() with MAC_TX_NO_ENQUEUE flag set.
2688  * In the default and Tx fanout mode, the un-transmitted mblks will be
2689  * returned back to the clients when the driver runs out of Tx descs.
2690  * SRS_TX_WAKEUP_CLIENT (or S_RING_WAKEUP_CLIENT) will be set in SRS (or
2691  * soft ring) so that the clients can be woken up when Tx desc become
2692  * available. When running in serializer or bandwidth mode mode,
2693  * SRS_TX_WAKEUP_CLIENT will be set when tx hi-watermark is reached.
2694  */
2695 
2696 mac_tx_func_t
2697 mac_tx_get_func(uint32_t mode)
2698 {
2699         return (mac_tx_mode_list[mode].mac_tx_func);
2700 }
2701 
2702 /* ARGSUSED */
2703 static mac_tx_cookie_t
2704 mac_tx_single_ring_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2705     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2706 {
2707         mac_srs_tx_t            *srs_tx = &mac_srs->srs_tx;
2708         mac_tx_stats_t          stats;
2709         mac_tx_cookie_t         cookie = NULL;
2710 
2711         ASSERT(srs_tx->st_mode == SRS_TX_DEFAULT);
2712 
2713         /* Regular case with a single Tx ring */
2714         /*
2715          * SRS_TX_BLOCKED is set when underlying NIC runs
2716          * out of Tx descs and messages start getting
2717          * queued. It won't get reset until
2718          * tx_srs_drain() completely drains out the
2719          * messages.
2720          */
2721         if ((mac_srs->srs_state & SRS_ENQUEUED) != 0) {
2722                 /* Tx descs/resources not available */
2723                 mutex_enter(&mac_srs->srs_lock);
2724                 if ((mac_srs->srs_state & SRS_ENQUEUED) != 0) {
2725                         cookie = mac_tx_srs_no_desc(mac_srs, mp_chain,
2726                             flag, ret_mp);
2727                         mutex_exit(&mac_srs->srs_lock);
2728                         return (cookie);
2729                 }
2730                 /*
2731                  * While we were computing mblk count, the
2732                  * flow control condition got relieved.
2733                  * Continue with the transmission.
2734                  */
2735                 mutex_exit(&mac_srs->srs_lock);
2736         }
2737 
2738         mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2739             mp_chain, &stats);
2740 
2741         /*
2742          * Multiple threads could be here sending packets.
2743          * Under such conditions, it is not possible to
2744          * automically set SRS_TX_BLOCKED bit to indicate
2745          * out of tx desc condition. To atomically set
2746          * this, we queue the returned packet and do
2747          * the setting of SRS_TX_BLOCKED in
2748          * mac_tx_srs_drain().
2749          */
2750         if (mp_chain != NULL) {
2751                 mutex_enter(&mac_srs->srs_lock);
2752                 cookie = mac_tx_srs_no_desc(mac_srs, mp_chain, flag, ret_mp);
2753                 mutex_exit(&mac_srs->srs_lock);
2754                 return (cookie);
2755         }
2756         SRS_TX_STATS_UPDATE(mac_srs, &stats);
2757 
2758         return (NULL);
2759 }
2760 
2761 /*
2762  * mac_tx_serialize_mode
2763  *
2764  * This is an experimental mode implemented as per the request of PAE.
2765  * In this mode, all callers attempting to send a packet to the NIC
2766  * will get serialized. Only one thread at any time will access the
2767  * NIC to send the packet out.
2768  */
2769 /* ARGSUSED */
2770 static mac_tx_cookie_t
2771 mac_tx_serializer_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2772     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2773 {
2774         mac_tx_stats_t          stats;
2775         mac_tx_cookie_t         cookie = NULL;
2776         mac_srs_tx_t            *srs_tx = &mac_srs->srs_tx;
2777 
2778         /* Single ring, serialize below */
2779         ASSERT(srs_tx->st_mode == SRS_TX_SERIALIZE);
2780         mutex_enter(&mac_srs->srs_lock);
2781         if ((mac_srs->srs_first != NULL) ||
2782             (mac_srs->srs_state & SRS_PROC)) {
2783                 /*
2784                  * In serialization mode, queue all packets until
2785                  * TX_HIWAT is set.
2786                  * If drop bit is set, drop if TX_HIWAT is set.
2787                  * If no_enqueue is set, still enqueue until hiwat
2788                  * is set and return mblks after TX_HIWAT is set.
2789                  */
2790                 cookie = mac_tx_srs_enqueue(mac_srs, mp_chain,
2791                     flag, NULL, ret_mp);
2792                 mutex_exit(&mac_srs->srs_lock);
2793                 return (cookie);
2794         }
2795         /*
2796          * No packets queued, nothing on proc and no flow
2797          * control condition. Fast-path, ok. Do inline
2798          * processing.
2799          */
2800         mac_srs->srs_state |= SRS_PROC;
2801         mutex_exit(&mac_srs->srs_lock);
2802 
2803         mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
2804             mp_chain, &stats);
2805 
2806         mutex_enter(&mac_srs->srs_lock);
2807         mac_srs->srs_state &= ~SRS_PROC;
2808         if (mp_chain != NULL) {
2809                 cookie = mac_tx_srs_enqueue(mac_srs,
2810                     mp_chain, flag, NULL, ret_mp);
2811         }
2812         if (mac_srs->srs_first != NULL) {
2813                 /*
2814                  * We processed inline our packet and a new
2815                  * packet/s got queued while we were
2816                  * processing. Wakeup srs worker
2817                  */
2818                 cv_signal(&mac_srs->srs_async);
2819         }
2820         mutex_exit(&mac_srs->srs_lock);
2821 
2822         if (cookie == NULL)
2823                 SRS_TX_STATS_UPDATE(mac_srs, &stats);
2824 
2825         return (cookie);
2826 }
2827 
2828 /*
2829  * mac_tx_fanout_mode
2830  *
2831  * In this mode, the SRS will have access to multiple Tx rings to send
2832  * the packet out. The fanout hint that is passed as an argument is
2833  * used to find an appropriate ring to fanout the traffic. Each Tx
2834  * ring, in turn,  will have a soft ring associated with it. If a Tx
2835  * ring runs out of Tx desc's the returned packet will be queued in
2836  * the soft ring associated with that Tx ring. The srs itself will not
2837  * queue any packets.
2838  */
2839 
2840 #define MAC_TX_SOFT_RING_PROCESS(chain) {                               \
2841         index = COMPUTE_INDEX(hash, mac_srs->srs_tx_ring_count),     \
2842         softring = mac_srs->srs_tx_soft_rings[index];                        \
2843         cookie = mac_tx_soft_ring_process(softring, chain, flag, ret_mp); \
2844         DTRACE_PROBE2(tx__fanout, uint64_t, hash, uint_t, index);       \
2845 }
2846 
2847 static mac_tx_cookie_t
2848 mac_tx_fanout_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2849     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2850 {
2851         mac_soft_ring_t         *softring;
2852         uint64_t                hash;
2853         uint_t                  index;
2854         mac_tx_cookie_t         cookie = NULL;
2855 
2856         ASSERT(mac_srs->srs_tx.st_mode == SRS_TX_FANOUT ||
2857             mac_srs->srs_tx.st_mode == SRS_TX_BW_FANOUT);
2858         if (fanout_hint != 0) {
2859                 /*
2860                  * The hint is specified by the caller, simply pass the
2861                  * whole chain to the soft ring.
2862                  */
2863                 hash = HASH_HINT(fanout_hint);
2864                 MAC_TX_SOFT_RING_PROCESS(mp_chain);
2865         } else {
2866                 mblk_t *last_mp, *cur_mp, *sub_chain;
2867                 uint64_t last_hash = 0;
2868                 uint_t media = mac_srs->srs_mcip->mci_mip->mi_info.mi_media;
2869 
2870                 /*
2871                  * Compute the hash from the contents (headers) of the
2872                  * packets of the mblk chain. Split the chains into
2873                  * subchains of the same conversation.
2874                  *
2875                  * Since there may be more than one ring used for
2876                  * sub-chains of the same call, and since the caller
2877                  * does not maintain per conversation state since it
2878                  * passed a zero hint, unsent subchains will be
2879                  * dropped.
2880                  */
2881 
2882                 flag |= MAC_DROP_ON_NO_DESC;
2883                 ret_mp = NULL;
2884 
2885                 ASSERT(ret_mp == NULL);
2886 
2887                 sub_chain = NULL;
2888                 last_mp = NULL;
2889 
2890                 for (cur_mp = mp_chain; cur_mp != NULL;
2891                     cur_mp = cur_mp->b_next) {
2892                         hash = mac_pkt_hash(media, cur_mp, MAC_PKT_HASH_L4,
2893                             B_TRUE);
2894                         if (last_hash != 0 && hash != last_hash) {
2895                                 /*
2896                                  * Starting a different subchain, send current
2897                                  * chain out.
2898                                  */
2899                                 ASSERT(last_mp != NULL);
2900                                 last_mp->b_next = NULL;
2901                                 MAC_TX_SOFT_RING_PROCESS(sub_chain);
2902                                 sub_chain = NULL;
2903                         }
2904 
2905                         /* add packet to subchain */
2906                         if (sub_chain == NULL)
2907                                 sub_chain = cur_mp;
2908                         last_mp = cur_mp;
2909                         last_hash = hash;
2910                 }
2911 
2912                 if (sub_chain != NULL) {
2913                         /* send last subchain */
2914                         ASSERT(last_mp != NULL);
2915                         last_mp->b_next = NULL;
2916                         MAC_TX_SOFT_RING_PROCESS(sub_chain);
2917                 }
2918 
2919                 cookie = NULL;
2920         }
2921 
2922         return (cookie);
2923 }
2924 
2925 /*
2926  * mac_tx_bw_mode
2927  *
2928  * In the bandwidth mode, Tx srs will allow packets to go down to Tx ring
2929  * only if bw is available. Otherwise the packets will be queued in
2930  * SRS. If the SRS has multiple Tx rings, then packets will get fanned
2931  * out to a Tx rings.
2932  */
2933 static mac_tx_cookie_t
2934 mac_tx_bw_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
2935     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
2936 {
2937         int                     cnt, sz;
2938         mblk_t                  *tail;
2939         mac_tx_cookie_t         cookie = NULL;
2940         mac_srs_tx_t            *srs_tx = &mac_srs->srs_tx;
2941         clock_t                 now;
2942 
2943         ASSERT(TX_BANDWIDTH_MODE(mac_srs));
2944         ASSERT(mac_srs->srs_type & SRST_BW_CONTROL);
2945         mutex_enter(&mac_srs->srs_lock);
2946         if (mac_srs->srs_bw->mac_bw_limit == 0) {
2947                 /*
2948                  * zero bandwidth, no traffic is sent: drop the packets,
2949                  * or return the whole chain if the caller requests all
2950                  * unsent packets back.
2951                  */
2952                 if (flag & MAC_TX_NO_ENQUEUE) {
2953                         cookie = (mac_tx_cookie_t)mac_srs;
2954                         *ret_mp = mp_chain;
2955                 } else {
2956                         MAC_TX_SRS_DROP_MESSAGE(mac_srs, mp_chain, cookie);
2957                 }
2958                 mutex_exit(&mac_srs->srs_lock);
2959                 return (cookie);
2960         } else if ((mac_srs->srs_first != NULL) ||
2961             (mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED)) {
2962                 cookie = mac_tx_srs_enqueue(mac_srs, mp_chain, flag,
2963                     fanout_hint, ret_mp);
2964                 mutex_exit(&mac_srs->srs_lock);
2965                 return (cookie);
2966         }
2967         MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
2968         now = ddi_get_lbolt();
2969         if (mac_srs->srs_bw->mac_bw_curr_time != now) {
2970                 mac_srs->srs_bw->mac_bw_curr_time = now;
2971                 mac_srs->srs_bw->mac_bw_used = 0;
2972         } else if (mac_srs->srs_bw->mac_bw_used >
2973             mac_srs->srs_bw->mac_bw_limit) {
2974                 mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
2975                 MAC_TX_SRS_ENQUEUE_CHAIN(mac_srs,
2976                     mp_chain, tail, cnt, sz);
2977                 /*
2978                  * Wakeup worker thread. Note that worker
2979                  * thread has to be woken up so that it
2980                  * can fire up the timer to be woken up
2981                  * on the next tick. Also once
2982                  * BW_ENFORCED is set, it can only be
2983                  * reset by srs_worker thread. Until then
2984                  * all packets will get queued up in SRS
2985                  * and hence this this code path won't be
2986                  * entered until BW_ENFORCED is reset.
2987                  */
2988                 cv_signal(&mac_srs->srs_async);
2989                 mutex_exit(&mac_srs->srs_lock);
2990                 return (cookie);
2991         }
2992 
2993         mac_srs->srs_bw->mac_bw_used += sz;
2994         mutex_exit(&mac_srs->srs_lock);
2995 
2996         if (srs_tx->st_mode == SRS_TX_BW_FANOUT) {
2997                 mac_soft_ring_t *softring;
2998                 uint_t indx, hash;
2999 
3000                 hash = HASH_HINT(fanout_hint);
3001                 indx = COMPUTE_INDEX(hash,
3002                     mac_srs->srs_tx_ring_count);
3003                 softring = mac_srs->srs_tx_soft_rings[indx];
3004                 return (mac_tx_soft_ring_process(softring, mp_chain, flag,
3005                     ret_mp));
3006         } else if (srs_tx->st_mode == SRS_TX_BW_AGGR) {
3007                 return (mac_tx_aggr_mode(mac_srs, mp_chain,
3008                     fanout_hint, flag, ret_mp));
3009         } else {
3010                 mac_tx_stats_t          stats;
3011 
3012                 mp_chain = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
3013                     mp_chain, &stats);
3014 
3015                 if (mp_chain != NULL) {
3016                         mutex_enter(&mac_srs->srs_lock);
3017                         MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
3018                         if (mac_srs->srs_bw->mac_bw_used > sz)
3019                                 mac_srs->srs_bw->mac_bw_used -= sz;
3020                         else
3021                                 mac_srs->srs_bw->mac_bw_used = 0;
3022                         cookie = mac_tx_srs_enqueue(mac_srs, mp_chain, flag,
3023                             fanout_hint, ret_mp);
3024                         mutex_exit(&mac_srs->srs_lock);
3025                         return (cookie);
3026                 }
3027                 SRS_TX_STATS_UPDATE(mac_srs, &stats);
3028 
3029                 return (NULL);
3030         }
3031 }
3032 
3033 /*
3034  * mac_tx_aggr_mode
3035  *
3036  * This routine invokes an aggr function, aggr_find_tx_ring(), to find
3037  * a (pseudo) Tx ring belonging to a port on which the packet has to
3038  * be sent. aggr_find_tx_ring() first finds the outgoing port based on
3039  * L2/L3/L4 policy and then uses the fanout_hint passed to it to pick
3040  * a Tx ring from the selected port.
3041  *
3042  * Note that a port can be deleted from the aggregation. In such a case,
3043  * the aggregation layer first separates the port from the rest of the
3044  * ports making sure that port (and thus any Tx rings associated with
3045  * it) won't get selected in the call to aggr_find_tx_ring() function.
3046  * Later calls are made to mac_group_rem_ring() passing pseudo Tx ring
3047  * handles one by one which in turn will quiesce the Tx SRS and remove
3048  * the soft ring associated with the pseudo Tx ring. Unlike Rx side
3049  * where a cookie is used to protect against mac_rx_ring() calls on
3050  * rings that have been removed, no such cookie is needed on the Tx
3051  * side as the pseudo Tx ring won't be available anymore to
3052  * aggr_find_tx_ring() once the port has been removed.
3053  */
3054 static mac_tx_cookie_t
3055 mac_tx_aggr_mode(mac_soft_ring_set_t *mac_srs, mblk_t *mp_chain,
3056     uintptr_t fanout_hint, uint16_t flag, mblk_t **ret_mp)
3057 {
3058         mac_srs_tx_t            *srs_tx = &mac_srs->srs_tx;
3059         mac_tx_ring_fn_t        find_tx_ring_fn;
3060         mac_ring_handle_t       ring = NULL;
3061         void                    *arg;
3062         mac_soft_ring_t         *sringp;
3063 
3064         find_tx_ring_fn = srs_tx->st_capab_aggr.mca_find_tx_ring_fn;
3065         arg = srs_tx->st_capab_aggr.mca_arg;
3066         if (find_tx_ring_fn(arg, mp_chain, fanout_hint, &ring) == NULL)
3067                 return (NULL);
3068         sringp = srs_tx->st_soft_rings[((mac_ring_t *)ring)->mr_index];
3069         return (mac_tx_soft_ring_process(sringp, mp_chain, flag, ret_mp));
3070 }
3071 
3072 void
3073 mac_tx_invoke_callbacks(mac_client_impl_t *mcip, mac_tx_cookie_t cookie)
3074 {
3075         mac_cb_t *mcb;
3076         mac_tx_notify_cb_t *mtnfp;
3077 
3078         /* Wakeup callback registered clients */
3079         MAC_CALLBACK_WALKER_INC(&mcip->mci_tx_notify_cb_info);
3080         for (mcb = mcip->mci_tx_notify_cb_list; mcb != NULL;
3081             mcb = mcb->mcb_nextp) {
3082                 mtnfp = (mac_tx_notify_cb_t *)mcb->mcb_objp;
3083                 mtnfp->mtnf_fn(mtnfp->mtnf_arg, cookie);
3084         }
3085         MAC_CALLBACK_WALKER_DCR(&mcip->mci_tx_notify_cb_info,
3086             &mcip->mci_tx_notify_cb_list);
3087 }
3088 
3089 /* ARGSUSED */
3090 void
3091 mac_tx_srs_drain(mac_soft_ring_set_t *mac_srs, uint_t proc_type)
3092 {
3093         mblk_t                  *head, *tail;
3094         size_t                  sz;
3095         uint32_t                tx_mode;
3096         uint_t                  saved_pkt_count;
3097         mac_tx_stats_t          stats;
3098         mac_srs_tx_t            *srs_tx = &mac_srs->srs_tx;
3099         clock_t                 now;
3100 
3101         saved_pkt_count = 0;
3102         ASSERT(mutex_owned(&mac_srs->srs_lock));
3103         ASSERT(!(mac_srs->srs_state & SRS_PROC));
3104 
3105         mac_srs->srs_state |= SRS_PROC;
3106 
3107         tx_mode = srs_tx->st_mode;
3108         if (tx_mode == SRS_TX_DEFAULT || tx_mode == SRS_TX_SERIALIZE) {
3109                 if (mac_srs->srs_first != NULL) {
3110                         head = mac_srs->srs_first;
3111                         tail = mac_srs->srs_last;
3112                         saved_pkt_count = mac_srs->srs_count;
3113                         mac_srs->srs_first = NULL;
3114                         mac_srs->srs_last = NULL;
3115                         mac_srs->srs_count = 0;
3116                         mutex_exit(&mac_srs->srs_lock);
3117 
3118                         head = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
3119                             head, &stats);
3120 
3121                         mutex_enter(&mac_srs->srs_lock);
3122                         if (head != NULL) {
3123                                 /* Device out of tx desc, set block */
3124                                 if (head->b_next == NULL)
3125                                         VERIFY(head == tail);
3126                                 tail->b_next = mac_srs->srs_first;
3127                                 mac_srs->srs_first = head;
3128                                 mac_srs->srs_count +=
3129                                     (saved_pkt_count - stats.mts_opackets);
3130                                 if (mac_srs->srs_last == NULL)
3131                                         mac_srs->srs_last = tail;
3132                                 MAC_TX_SRS_BLOCK(mac_srs, head);
3133                         } else {
3134                                 srs_tx->st_woken_up = B_FALSE;
3135                                 SRS_TX_STATS_UPDATE(mac_srs, &stats);
3136                         }
3137                 }
3138         } else if (tx_mode == SRS_TX_BW) {
3139                 /*
3140                  * We are here because the timer fired and we have some data
3141                  * to tranmit. Also mac_tx_srs_worker should have reset
3142                  * SRS_BW_ENFORCED flag
3143                  */
3144                 ASSERT(!(mac_srs->srs_bw->mac_bw_state & SRS_BW_ENFORCED));
3145                 head = tail = mac_srs->srs_first;
3146                 while (mac_srs->srs_first != NULL) {
3147                         tail = mac_srs->srs_first;
3148                         tail->b_prev = NULL;
3149                         mac_srs->srs_first = tail->b_next;
3150                         if (mac_srs->srs_first == NULL)
3151                                 mac_srs->srs_last = NULL;
3152                         mac_srs->srs_count--;
3153                         sz = msgdsize(tail);
3154                         mac_srs->srs_size -= sz;
3155                         saved_pkt_count++;
3156                         MAC_TX_UPDATE_BW_INFO(mac_srs, sz);
3157 
3158                         if (mac_srs->srs_bw->mac_bw_used <
3159                             mac_srs->srs_bw->mac_bw_limit)
3160                                 continue;
3161 
3162                         now = ddi_get_lbolt();
3163                         if (mac_srs->srs_bw->mac_bw_curr_time != now) {
3164                                 mac_srs->srs_bw->mac_bw_curr_time = now;
3165                                 mac_srs->srs_bw->mac_bw_used = sz;
3166                                 continue;
3167                         }
3168                         mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
3169                         break;
3170                 }
3171 
3172                 ASSERT((head == NULL && tail == NULL) ||
3173                     (head != NULL && tail != NULL));
3174                 if (tail != NULL) {
3175                         tail->b_next = NULL;
3176                         mutex_exit(&mac_srs->srs_lock);
3177 
3178                         head = mac_tx_send(srs_tx->st_arg1, srs_tx->st_arg2,
3179                             head, &stats);
3180 
3181                         mutex_enter(&mac_srs->srs_lock);
3182                         if (head != NULL) {
3183                                 uint_t size_sent;
3184 
3185                                 /* Device out of tx desc, set block */
3186                                 if (head->b_next == NULL)
3187                                         VERIFY(head == tail);
3188                                 tail->b_next = mac_srs->srs_first;
3189                                 mac_srs->srs_first = head;
3190                                 mac_srs->srs_count +=
3191                                     (saved_pkt_count - stats.mts_opackets);
3192                                 if (mac_srs->srs_last == NULL)
3193                                         mac_srs->srs_last = tail;
3194                                 size_sent = sz - stats.mts_obytes;
3195                                 mac_srs->srs_size += size_sent;
3196                                 mac_srs->srs_bw->mac_bw_sz += size_sent;
3197                                 if (mac_srs->srs_bw->mac_bw_used > size_sent) {
3198                                         mac_srs->srs_bw->mac_bw_used -=
3199                                             size_sent;
3200                                 } else {
3201                                         mac_srs->srs_bw->mac_bw_used = 0;
3202                                 }
3203                                 MAC_TX_SRS_BLOCK(mac_srs, head);
3204                         } else {
3205                                 srs_tx->st_woken_up = B_FALSE;
3206                                 SRS_TX_STATS_UPDATE(mac_srs, &stats);
3207                         }
3208                 }
3209         } else if (tx_mode == SRS_TX_BW_FANOUT || tx_mode == SRS_TX_BW_AGGR) {
3210                 mblk_t *prev;
3211                 uint64_t hint;
3212 
3213                 /*
3214                  * We are here because the timer fired and we
3215                  * have some quota to tranmit.
3216                  */
3217                 prev = NULL;
3218                 head = tail = mac_srs->srs_first;
3219                 while (mac_srs->srs_first != NULL) {
3220                         tail = mac_srs->srs_first;
3221                         mac_srs->srs_first = tail->b_next;
3222                         if (mac_srs->srs_first == NULL)
3223                                 mac_srs->srs_last = NULL;
3224                         mac_srs->srs_count--;
3225                         sz = msgdsize(tail);
3226                         mac_srs->srs_size -= sz;
3227                         mac_srs->srs_bw->mac_bw_used += sz;
3228                         if (prev == NULL)
3229                                 hint = (ulong_t)tail->b_prev;
3230                         if (hint != (ulong_t)tail->b_prev) {
3231                                 prev->b_next = NULL;
3232                                 mutex_exit(&mac_srs->srs_lock);
3233                                 TX_SRS_TO_SOFT_RING(mac_srs, head, hint);
3234                                 head = tail;
3235                                 hint = (ulong_t)tail->b_prev;
3236                                 mutex_enter(&mac_srs->srs_lock);
3237                         }
3238 
3239                         prev = tail;
3240                         tail->b_prev = NULL;
3241                         if (mac_srs->srs_bw->mac_bw_used <
3242                             mac_srs->srs_bw->mac_bw_limit)
3243                                 continue;
3244 
3245                         now = ddi_get_lbolt();
3246                         if (mac_srs->srs_bw->mac_bw_curr_time != now) {
3247                                 mac_srs->srs_bw->mac_bw_curr_time = now;
3248                                 mac_srs->srs_bw->mac_bw_used = 0;
3249                                 continue;
3250                         }
3251                         mac_srs->srs_bw->mac_bw_state |= SRS_BW_ENFORCED;
3252                         break;
3253                 }
3254                 ASSERT((head == NULL && tail == NULL) ||
3255                     (head != NULL && tail != NULL));
3256                 if (tail != NULL) {
3257                         tail->b_next = NULL;
3258                         mutex_exit(&mac_srs->srs_lock);
3259                         TX_SRS_TO_SOFT_RING(mac_srs, head, hint);
3260                         mutex_enter(&mac_srs->srs_lock);
3261                 }
3262         }
3263         /*
3264          * SRS_TX_FANOUT case not considered here because packets
3265          * won't be queued in the SRS for this case. Packets will
3266          * be sent directly to soft rings underneath and if there
3267          * is any queueing at all, it would be in Tx side soft
3268          * rings.
3269          */
3270 
3271         /*
3272          * When srs_count becomes 0, reset SRS_TX_HIWAT and
3273          * SRS_TX_WAKEUP_CLIENT and wakeup registered clients.
3274          */
3275         if (mac_srs->srs_count == 0 && (mac_srs->srs_state &
3276             (SRS_TX_HIWAT | SRS_TX_WAKEUP_CLIENT | SRS_ENQUEUED))) {
3277                 mac_client_impl_t *mcip = mac_srs->srs_mcip;
3278                 boolean_t wakeup_required = B_FALSE;
3279 
3280                 if (mac_srs->srs_state &
3281                     (SRS_TX_HIWAT|SRS_TX_WAKEUP_CLIENT)) {
3282                         wakeup_required = B_TRUE;
3283                 }
3284                 mac_srs->srs_state &= ~(SRS_TX_HIWAT |
3285                     SRS_TX_WAKEUP_CLIENT | SRS_ENQUEUED);
3286                 mutex_exit(&mac_srs->srs_lock);
3287                 if (wakeup_required) {
3288                         mac_tx_invoke_callbacks(mcip, (mac_tx_cookie_t)mac_srs);
3289                         /*
3290                          * If the client is not the primary MAC client, then we
3291                          * need to send the notification to the clients upper
3292                          * MAC, i.e. mci_upper_mip.
3293                          */
3294                         mac_tx_notify(mcip->mci_upper_mip != NULL ?
3295                             mcip->mci_upper_mip : mcip->mci_mip);
3296                 }
3297                 mutex_enter(&mac_srs->srs_lock);
3298         }
3299         mac_srs->srs_state &= ~SRS_PROC;
3300 }
3301 
3302 /*
3303  * Given a packet, get the flow_entry that identifies the flow
3304  * to which that packet belongs. The flow_entry will contain
3305  * the transmit function to be used to send the packet. If the
3306  * function returns NULL, the packet should be sent using the
3307  * underlying NIC.
3308  */
3309 static flow_entry_t *
3310 mac_tx_classify(mac_impl_t *mip, mblk_t *mp)
3311 {
3312         flow_entry_t            *flent = NULL;
3313         mac_client_impl_t       *mcip;
3314         int     err;
3315 
3316         /*
3317          * Do classification on the packet.
3318          */
3319         err = mac_flow_lookup(mip->mi_flow_tab, mp, FLOW_OUTBOUND, &flent);
3320         if (err != 0)
3321                 return (NULL);
3322 
3323         /*
3324          * This flent might just be an additional one on the MAC client,
3325          * i.e. for classification purposes (different fdesc), however
3326          * the resources, SRS et. al., are in the mci_flent, so if
3327          * this isn't the mci_flent, we need to get it.
3328          */
3329         if ((mcip = flent->fe_mcip) != NULL && mcip->mci_flent != flent) {
3330                 FLOW_REFRELE(flent);
3331                 flent = mcip->mci_flent;
3332                 FLOW_TRY_REFHOLD(flent, err);
3333                 if (err != 0)
3334                         return (NULL);
3335         }
3336 
3337         return (flent);
3338 }
3339 
3340 /*
3341  * This macro is only meant to be used by mac_tx_send().
3342  */
3343 #define CHECK_VID_AND_ADD_TAG(mp) {                     \
3344         if (vid_check) {                                \
3345                 int err = 0;                            \
3346                                                         \
3347                 MAC_VID_CHECK(src_mcip, (mp), err);     \
3348                 if (err != 0) {                         \
3349                         freemsg((mp));                  \
3350                         (mp) = next;                    \
3351                         oerrors++;                      \
3352                         continue;                       \
3353                 }                                       \
3354         }                                               \
3355         if (add_tag) {                                  \
3356                 (mp) = mac_add_vlan_tag((mp), 0, vid);  \
3357                 if ((mp) == NULL) {                     \
3358                         (mp) = next;                    \
3359                         oerrors++;                      \
3360                         continue;                       \
3361                 }                                       \
3362         }                                               \
3363 }
3364 
3365 mblk_t *
3366 mac_tx_send(mac_client_handle_t mch, mac_ring_handle_t ring, mblk_t *mp_chain,
3367     mac_tx_stats_t *stats)
3368 {
3369         mac_client_impl_t *src_mcip = (mac_client_impl_t *)mch;
3370         mac_impl_t *mip = src_mcip->mci_mip;
3371         uint_t obytes = 0, opackets = 0, oerrors = 0;
3372         mblk_t *mp = NULL, *next;
3373         boolean_t vid_check, add_tag;
3374         uint16_t vid = 0;
3375 
3376         if (mip->mi_nclients > 1) {
3377                 vid_check = MAC_VID_CHECK_NEEDED(src_mcip);
3378                 add_tag = MAC_TAG_NEEDED(src_mcip);
3379                 if (add_tag)
3380                         vid = mac_client_vid(mch);
3381         } else {
3382                 ASSERT(mip->mi_nclients == 1);
3383                 vid_check = add_tag = B_FALSE;
3384         }
3385 
3386         /*
3387          * Fastpath: if there's only one client, we simply send
3388          * the packet down to the underlying NIC.
3389          */
3390         if (mip->mi_nactiveclients == 1) {
3391                 DTRACE_PROBE2(fastpath,
3392                     mac_client_impl_t *, src_mcip, mblk_t *, mp_chain);
3393 
3394                 mp = mp_chain;
3395                 while (mp != NULL) {
3396                         next = mp->b_next;
3397                         mp->b_next = NULL;
3398                         opackets++;
3399                         obytes += (mp->b_cont == NULL ? MBLKL(mp) :
3400                             msgdsize(mp));
3401 
3402                         CHECK_VID_AND_ADD_TAG(mp);
3403                         MAC_TX(mip, ring, mp, src_mcip);
3404 
3405                         /*
3406                          * If the driver is out of descriptors and does a
3407                          * partial send it will return a chain of unsent
3408                          * mblks. Adjust the accounting stats.
3409                          */
3410                         if (mp != NULL) {
3411                                 opackets--;
3412                                 obytes -= msgdsize(mp);
3413                                 mp->b_next = next;
3414                                 break;
3415                         }
3416                         mp = next;
3417                 }
3418                 goto done;
3419         }
3420 
3421         /*
3422          * No fastpath, we either have more than one MAC client
3423          * defined on top of the same MAC, or one or more MAC
3424          * client promiscuous callbacks.
3425          */
3426         DTRACE_PROBE3(slowpath, mac_client_impl_t *,
3427             src_mcip, int, mip->mi_nclients, mblk_t *, mp_chain);
3428 
3429         mp = mp_chain;
3430         while (mp != NULL) {
3431                 flow_entry_t *dst_flow_ent;
3432                 void *flow_cookie;
3433                 size_t  pkt_size;
3434                 mblk_t *mp1;
3435 
3436                 next = mp->b_next;
3437                 mp->b_next = NULL;
3438                 opackets++;
3439                 pkt_size = (mp->b_cont == NULL ? MBLKL(mp) : msgdsize(mp));
3440                 obytes += pkt_size;
3441                 CHECK_VID_AND_ADD_TAG(mp);
3442 
3443                 /*
3444                  * Find the destination.
3445                  */
3446                 dst_flow_ent = mac_tx_classify(mip, mp);
3447 
3448                 if (dst_flow_ent != NULL) {
3449                         size_t  hdrsize;
3450                         int     err = 0;
3451 
3452                         if (mip->mi_info.mi_nativemedia == DL_ETHER) {
3453                                 struct ether_vlan_header *evhp =
3454                                     (struct ether_vlan_header *)mp->b_rptr;
3455 
3456                                 if (ntohs(evhp->ether_tpid) == ETHERTYPE_VLAN)
3457                                         hdrsize = sizeof (*evhp);
3458                                 else
3459                                         hdrsize = sizeof (struct ether_header);
3460                         } else {
3461                                 mac_header_info_t       mhi;
3462 
3463                                 err = mac_header_info((mac_handle_t)mip,
3464                                     mp, &mhi);
3465                                 if (err == 0)
3466                                         hdrsize = mhi.mhi_hdrsize;
3467                         }
3468 
3469                         /*
3470                          * Got a matching flow. It's either another
3471                          * MAC client, or a broadcast/multicast flow.
3472                          * Make sure the packet size is within the
3473                          * allowed size. If not drop the packet and
3474                          * move to next packet.
3475                          */
3476                         if (err != 0 ||
3477                             (pkt_size - hdrsize) > mip->mi_sdu_max) {
3478                                 oerrors++;
3479                                 DTRACE_PROBE2(loopback__drop, size_t, pkt_size,
3480                                     mblk_t *, mp);
3481                                 freemsg(mp);
3482                                 mp = next;
3483                                 FLOW_REFRELE(dst_flow_ent);
3484                                 continue;
3485                         }
3486                         flow_cookie = mac_flow_get_client_cookie(dst_flow_ent);
3487                         if (flow_cookie != NULL) {
3488                                 /*
3489                                  * The vnic_bcast_send function expects
3490                                  * to receive the sender MAC client
3491                                  * as value for arg2.
3492                                  */
3493                                 mac_bcast_send(flow_cookie, src_mcip, mp,
3494                                     B_TRUE);
3495                         } else {
3496                                 /*
3497                                  * loopback the packet to a local MAC
3498                                  * client. We force a context switch
3499                                  * if both source and destination MAC
3500                                  * clients are used by IP, i.e.
3501                                  * bypass is set.
3502                                  */
3503                                 boolean_t do_switch;
3504                                 mac_client_impl_t *dst_mcip =
3505                                     dst_flow_ent->fe_mcip;
3506 
3507                                 /*
3508                                  * Check if there are promiscuous mode
3509                                  * callbacks defined. This check is
3510                                  * done here in the 'else' case and
3511                                  * not in other cases because this
3512                                  * path is for local loopback
3513                                  * communication which does not go
3514                                  * through MAC_TX(). For paths that go
3515                                  * through MAC_TX(), the promisc_list
3516                                  * check is done inside the MAC_TX()
3517                                  * macro.
3518                                  */
3519                                 if (mip->mi_promisc_list != NULL)
3520                                         mac_promisc_dispatch(mip, mp, src_mcip);
3521 
3522                                 do_switch = ((src_mcip->mci_state_flags &
3523                                     dst_mcip->mci_state_flags &
3524                                     MCIS_CLIENT_POLL_CAPABLE) != 0);
3525 
3526                                 if ((mp1 = mac_fix_cksum(mp)) != NULL) {
3527                                         (dst_flow_ent->fe_cb_fn)(
3528                                             dst_flow_ent->fe_cb_arg1,
3529                                             dst_flow_ent->fe_cb_arg2,
3530                                             mp1, do_switch);
3531                                 }
3532                         }
3533                         FLOW_REFRELE(dst_flow_ent);
3534                 } else {
3535                         /*
3536                          * Unknown destination, send via the underlying
3537                          * NIC.
3538                          */
3539                         MAC_TX(mip, ring, mp, src_mcip);
3540                         if (mp != NULL) {
3541                                 /*
3542                                  * Adjust for the last packet that
3543                                  * could not be transmitted
3544                                  */
3545                                 opackets--;
3546                                 obytes -= pkt_size;
3547                                 mp->b_next = next;
3548                                 break;
3549                         }
3550                 }
3551                 mp = next;
3552         }
3553 
3554 done:
3555         stats->mts_obytes = obytes;
3556         stats->mts_opackets = opackets;
3557         stats->mts_oerrors = oerrors;
3558         return (mp);
3559 }
3560 
3561 /*
3562  * mac_tx_srs_ring_present
3563  *
3564  * Returns whether the specified ring is part of the specified SRS.
3565  */
3566 boolean_t
3567 mac_tx_srs_ring_present(mac_soft_ring_set_t *srs, mac_ring_t *tx_ring)
3568 {
3569         int i;
3570         mac_soft_ring_t *soft_ring;
3571 
3572         if (srs->srs_tx.st_arg2 == tx_ring)
3573                 return (B_TRUE);
3574 
3575         for (i = 0; i < srs->srs_tx_ring_count; i++) {
3576                 soft_ring =  srs->srs_tx_soft_rings[i];
3577                 if (soft_ring->s_ring_tx_arg2 == tx_ring)
3578                         return (B_TRUE);
3579         }
3580 
3581         return (B_FALSE);
3582 }
3583 
3584 /*
3585  * mac_tx_srs_get_soft_ring
3586  *
3587  * Returns the TX soft ring associated with the given ring, if present.
3588  */
3589 mac_soft_ring_t *
3590 mac_tx_srs_get_soft_ring(mac_soft_ring_set_t *srs, mac_ring_t *tx_ring)
3591 {
3592         int             i;
3593         mac_soft_ring_t *soft_ring;
3594 
3595         if (srs->srs_tx.st_arg2 == tx_ring)
3596                 return (NULL);
3597 
3598         for (i = 0; i < srs->srs_tx_ring_count; i++) {
3599                 soft_ring =  srs->srs_tx_soft_rings[i];
3600                 if (soft_ring->s_ring_tx_arg2 == tx_ring)
3601                         return (soft_ring);
3602         }
3603 
3604         return (NULL);
3605 }
3606 
3607 /*
3608  * mac_tx_srs_wakeup
3609  *
3610  * Called when Tx desc become available. Wakeup the appropriate worker
3611  * thread after resetting the SRS_TX_BLOCKED/S_RING_BLOCK bit in the
3612  * state field.
3613  */
3614 void
3615 mac_tx_srs_wakeup(mac_soft_ring_set_t *mac_srs, mac_ring_handle_t ring)
3616 {
3617         int i;
3618         mac_soft_ring_t *sringp;
3619         mac_srs_tx_t *srs_tx = &mac_srs->srs_tx;
3620 
3621         mutex_enter(&mac_srs->srs_lock);
3622         /*
3623          * srs_tx_ring_count == 0 is the single ring mode case. In
3624          * this mode, there will not be Tx soft rings associated
3625          * with the SRS.
3626          */
3627         if (!MAC_TX_SOFT_RINGS(mac_srs)) {
3628                 if (srs_tx->st_arg2 == ring &&
3629                     mac_srs->srs_state & SRS_TX_BLOCKED) {
3630                         mac_srs->srs_state &= ~SRS_TX_BLOCKED;
3631                         srs_tx->st_stat.mts_unblockcnt++;
3632                         cv_signal(&mac_srs->srs_async);
3633                 }
3634                 /*
3635                  * A wakeup can come before tx_srs_drain() could
3636                  * grab srs lock and set SRS_TX_BLOCKED. So
3637                  * always set woken_up flag when we come here.
3638                  */
3639                 srs_tx->st_woken_up = B_TRUE;
3640                 mutex_exit(&mac_srs->srs_lock);
3641                 return;
3642         }
3643 
3644         /*
3645          * If you are here, it is for FANOUT, BW_FANOUT,
3646          * AGGR_MODE or AGGR_BW_MODE case
3647          */
3648         for (i = 0; i < mac_srs->srs_tx_ring_count; i++) {
3649                 sringp = mac_srs->srs_tx_soft_rings[i];
3650                 mutex_enter(&sringp->s_ring_lock);
3651                 if (sringp->s_ring_tx_arg2 == ring) {
3652                         if (sringp->s_ring_state & S_RING_BLOCK) {
3653                                 sringp->s_ring_state &= ~S_RING_BLOCK;
3654                                 sringp->s_st_stat.mts_unblockcnt++;
3655                                 cv_signal(&sringp->s_ring_async);
3656                         }
3657                         sringp->s_ring_tx_woken_up = B_TRUE;
3658                 }
3659                 mutex_exit(&sringp->s_ring_lock);
3660         }
3661         mutex_exit(&mac_srs->srs_lock);
3662 }
3663 
3664 /*
3665  * Once the driver is done draining, send a MAC_NOTE_TX notification to unleash
3666  * the blocked clients again.
3667  */
3668 void
3669 mac_tx_notify(mac_impl_t *mip)
3670 {
3671         i_mac_notify(mip, MAC_NOTE_TX);
3672 }
3673 
3674 /*
3675  * RX SOFTRING RELATED FUNCTIONS
3676  *
3677  * These functions really belong in mac_soft_ring.c and here for
3678  * a short period.
3679  */
3680 
3681 #define SOFT_RING_ENQUEUE_CHAIN(ringp, mp, tail, cnt, sz) {             \
3682         /*                                                              \
3683          * Enqueue our mblk chain.                                      \
3684          */                                                             \
3685         ASSERT(MUTEX_HELD(&(ringp)->s_ring_lock));                       \
3686                                                                         \
3687         if ((ringp)->s_ring_last != NULL)                            \
3688                 (ringp)->s_ring_last->b_next = (mp);                      \
3689         else                                                            \
3690                 (ringp)->s_ring_first = (mp);                                \
3691         (ringp)->s_ring_last = (tail);                                       \
3692         (ringp)->s_ring_count += (cnt);                                      \
3693         ASSERT((ringp)->s_ring_count > 0);                                \
3694         if ((ringp)->s_ring_type & ST_RING_BW_CTL) {                     \
3695                 (ringp)->s_ring_size += sz;                          \
3696         }                                                               \
3697 }
3698 
3699 /*
3700  * Default entry point to deliver a packet chain to a MAC client.
3701  * If the MAC client has flows, do the classification with these
3702  * flows as well.
3703  */
3704 /* ARGSUSED */
3705 void
3706 mac_rx_deliver(void *arg1, mac_resource_handle_t mrh, mblk_t *mp_chain,
3707     mac_header_info_t *arg3)
3708 {
3709         mac_client_impl_t *mcip = arg1;
3710 
3711         if (mcip->mci_nvids == 1 &&
3712             !(mcip->mci_state_flags & MCIS_STRIP_DISABLE)) {
3713                 /*
3714                  * If the client has exactly one VID associated with it
3715                  * and striping of VLAN header is not disabled,
3716                  * remove the VLAN tag from the packet before
3717                  * passing it on to the client's receive callback.
3718                  * Note that this needs to be done after we dispatch
3719                  * the packet to the promiscuous listeners of the
3720                  * client, since they expect to see the whole
3721                  * frame including the VLAN headers.
3722                  */
3723                 mp_chain = mac_strip_vlan_tag_chain(mp_chain);
3724         }
3725 
3726         mcip->mci_rx_fn(mcip->mci_rx_arg, mrh, mp_chain, B_FALSE);
3727 }
3728 
3729 /*
3730  * mac_rx_soft_ring_process
3731  *
3732  * process a chain for a given soft ring. The number of packets queued
3733  * in the SRS and its associated soft rings (including this one) is
3734  * very small (tracked by srs_poll_pkt_cnt), then allow the entering
3735  * thread (interrupt or poll thread) to do inline processing. This
3736  * helps keep the latency down under low load.
3737  *
3738  * The proc and arg for each mblk is already stored in the mblk in
3739  * appropriate places.
3740  */
3741 /* ARGSUSED */
3742 void
3743 mac_rx_soft_ring_process(mac_client_impl_t *mcip, mac_soft_ring_t *ringp,
3744     mblk_t *mp_chain, mblk_t *tail, int cnt, size_t sz)
3745 {
3746         mac_direct_rx_t         proc;
3747         void                    *arg1;
3748         mac_resource_handle_t   arg2;
3749         mac_soft_ring_set_t     *mac_srs = ringp->s_ring_set;
3750 
3751         ASSERT(ringp != NULL);
3752         ASSERT(mp_chain != NULL);
3753         ASSERT(tail != NULL);
3754         ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3755 
3756         mutex_enter(&ringp->s_ring_lock);
3757         ringp->s_ring_total_inpkt += cnt;
3758         ringp->s_ring_total_rbytes += sz;
3759         if ((mac_srs->srs_rx.sr_poll_pkt_cnt <= 1) &&
3760             !(ringp->s_ring_type & ST_RING_WORKER_ONLY)) {
3761                 /* If on processor or blanking on, then enqueue and return */
3762                 if (ringp->s_ring_state & S_RING_BLANK ||
3763                     ringp->s_ring_state & S_RING_PROC) {
3764                         SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3765                         mutex_exit(&ringp->s_ring_lock);
3766                         return;
3767                 }
3768                 proc = ringp->s_ring_rx_func;
3769                 arg1 = ringp->s_ring_rx_arg1;
3770                 arg2 = ringp->s_ring_rx_arg2;
3771                 /*
3772                  * See if anything is already queued. If we are the
3773                  * first packet, do inline processing else queue the
3774                  * packet and do the drain.
3775                  */
3776                 if (ringp->s_ring_first == NULL) {
3777                         /*
3778                          * Fast-path, ok to process and nothing queued.
3779                          */
3780                         ringp->s_ring_run = curthread;
3781                         ringp->s_ring_state |= (S_RING_PROC);
3782 
3783                         mutex_exit(&ringp->s_ring_lock);
3784 
3785                         /*
3786                          * We are the chain of 1 packet so
3787                          * go through this fast path.
3788                          */
3789                         ASSERT(mp_chain->b_next == NULL);
3790 
3791                         (*proc)(arg1, arg2, mp_chain, NULL);
3792 
3793                         ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3794                         /*
3795                          * If we have a soft ring set which is doing
3796                          * bandwidth control, we need to decrement
3797                          * srs_size and count so it the SRS can have a
3798                          * accurate idea of what is the real data
3799                          * queued between SRS and its soft rings. We
3800                          * decrement the counters only when the packet
3801                          * gets processed by both SRS and the soft ring.
3802                          */
3803                         mutex_enter(&mac_srs->srs_lock);
3804                         MAC_UPDATE_SRS_COUNT_LOCKED(mac_srs, cnt);
3805                         MAC_UPDATE_SRS_SIZE_LOCKED(mac_srs, sz);
3806                         mutex_exit(&mac_srs->srs_lock);
3807 
3808                         mutex_enter(&ringp->s_ring_lock);
3809                         ringp->s_ring_run = NULL;
3810                         ringp->s_ring_state &= ~S_RING_PROC;
3811                         if (ringp->s_ring_state & S_RING_CLIENT_WAIT)
3812                                 cv_signal(&ringp->s_ring_client_cv);
3813 
3814                         if ((ringp->s_ring_first == NULL) ||
3815                             (ringp->s_ring_state & S_RING_BLANK)) {
3816                                 /*
3817                                  * We processed inline our packet and
3818                                  * nothing new has arrived or our
3819                                  * receiver doesn't want to receive
3820                                  * any packets. We are done.
3821                                  */
3822                                 mutex_exit(&ringp->s_ring_lock);
3823                                 return;
3824                         }
3825                 } else {
3826                         SOFT_RING_ENQUEUE_CHAIN(ringp,
3827                             mp_chain, tail, cnt, sz);
3828                 }
3829 
3830                 /*
3831                  * We are here because either we couldn't do inline
3832                  * processing (because something was already
3833                  * queued), or we had a chain of more than one
3834                  * packet, or something else arrived after we were
3835                  * done with inline processing.
3836                  */
3837                 ASSERT(MUTEX_HELD(&ringp->s_ring_lock));
3838                 ASSERT(ringp->s_ring_first != NULL);
3839 
3840                 ringp->s_ring_drain_func(ringp);
3841                 mutex_exit(&ringp->s_ring_lock);
3842                 return;
3843         } else {
3844                 /* ST_RING_WORKER_ONLY case */
3845                 SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3846                 mac_soft_ring_worker_wakeup(ringp);
3847                 mutex_exit(&ringp->s_ring_lock);
3848         }
3849 }
3850 
3851 /*
3852  * TX SOFTRING RELATED FUNCTIONS
3853  *
3854  * These functions really belong in mac_soft_ring.c and here for
3855  * a short period.
3856  */
3857 
3858 #define TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp, tail, cnt, sz) {          \
3859         ASSERT(MUTEX_HELD(&ringp->s_ring_lock));                 \
3860         ringp->s_ring_state |= S_RING_ENQUEUED;                              \
3861         SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);        \
3862 }
3863 
3864 /*
3865  * mac_tx_sring_queued
3866  *
3867  * When we are out of transmit descriptors and we already have a
3868  * queue that exceeds hiwat (or the client called us with
3869  * MAC_TX_NO_ENQUEUE or MAC_DROP_ON_NO_DESC flag), return the
3870  * soft ring pointer as the opaque cookie for the client enable
3871  * flow control.
3872  */
3873 static mac_tx_cookie_t
3874 mac_tx_sring_enqueue(mac_soft_ring_t *ringp, mblk_t *mp_chain, uint16_t flag,
3875     mblk_t **ret_mp)
3876 {
3877         int cnt;
3878         size_t sz;
3879         mblk_t *tail;
3880         mac_soft_ring_set_t *mac_srs = ringp->s_ring_set;
3881         mac_tx_cookie_t cookie = NULL;
3882         boolean_t wakeup_worker = B_TRUE;
3883 
3884         ASSERT(MUTEX_HELD(&ringp->s_ring_lock));
3885         MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
3886         if (flag & MAC_DROP_ON_NO_DESC) {
3887                 mac_pkt_drop(NULL, NULL, mp_chain, B_FALSE);
3888                 /* increment freed stats */
3889                 ringp->s_ring_drops += cnt;
3890                 cookie = (mac_tx_cookie_t)ringp;
3891         } else {
3892                 if (ringp->s_ring_first != NULL)
3893                         wakeup_worker = B_FALSE;
3894 
3895                 if (flag & MAC_TX_NO_ENQUEUE) {
3896                         /*
3897                          * If QUEUED is not set, queue the packet
3898                          * and let mac_tx_soft_ring_drain() set
3899                          * the TX_BLOCKED bit for the reasons
3900                          * explained above. Otherwise, return the
3901                          * mblks.
3902                          */
3903                         if (wakeup_worker) {
3904                                 TX_SOFT_RING_ENQUEUE_CHAIN(ringp,
3905                                     mp_chain, tail, cnt, sz);
3906                         } else {
3907                                 ringp->s_ring_state |= S_RING_WAKEUP_CLIENT;
3908                                 cookie = (mac_tx_cookie_t)ringp;
3909                                 *ret_mp = mp_chain;
3910                         }
3911                 } else {
3912                         boolean_t enqueue = B_TRUE;
3913 
3914                         if (ringp->s_ring_count > ringp->s_ring_tx_hiwat) {
3915                                 /*
3916                                  * flow-controlled. Store ringp in cookie
3917                                  * so that it can be returned as
3918                                  * mac_tx_cookie_t to client
3919                                  */
3920                                 ringp->s_ring_state |= S_RING_TX_HIWAT;
3921                                 cookie = (mac_tx_cookie_t)ringp;
3922                                 ringp->s_ring_hiwat_cnt++;
3923                                 if (ringp->s_ring_count >
3924                                     ringp->s_ring_tx_max_q_cnt) {
3925                                         /* increment freed stats */
3926                                         ringp->s_ring_drops += cnt;
3927                                         /*
3928                                          * b_prev may be set to the fanout hint
3929                                          * hence can't use freemsg directly
3930                                          */
3931                                         mac_pkt_drop(NULL, NULL,
3932                                             mp_chain, B_FALSE);
3933                                         DTRACE_PROBE1(tx_queued_hiwat,
3934                                             mac_soft_ring_t *, ringp);
3935                                         enqueue = B_FALSE;
3936                                 }
3937                         }
3938                         if (enqueue) {
3939                                 TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain,
3940                                     tail, cnt, sz);
3941                         }
3942                 }
3943                 if (wakeup_worker)
3944                         cv_signal(&ringp->s_ring_async);
3945         }
3946         return (cookie);
3947 }
3948 
3949 
3950 /*
3951  * mac_tx_soft_ring_process
3952  *
3953  * This routine is called when fanning out outgoing traffic among
3954  * multipe Tx rings.
3955  * Note that a soft ring is associated with a h/w Tx ring.
3956  */
3957 mac_tx_cookie_t
3958 mac_tx_soft_ring_process(mac_soft_ring_t *ringp, mblk_t *mp_chain,
3959     uint16_t flag, mblk_t **ret_mp)
3960 {
3961         mac_soft_ring_set_t *mac_srs = ringp->s_ring_set;
3962         int     cnt;
3963         size_t  sz;
3964         mblk_t  *tail;
3965         mac_tx_cookie_t cookie = NULL;
3966 
3967         ASSERT(ringp != NULL);
3968         ASSERT(mp_chain != NULL);
3969         ASSERT(MUTEX_NOT_HELD(&ringp->s_ring_lock));
3970         /*
3971          * The following modes can come here: SRS_TX_BW_FANOUT,
3972          * SRS_TX_FANOUT, SRS_TX_AGGR, SRS_TX_BW_AGGR.
3973          */
3974         ASSERT(MAC_TX_SOFT_RINGS(mac_srs));
3975         ASSERT(mac_srs->srs_tx.st_mode == SRS_TX_FANOUT ||
3976             mac_srs->srs_tx.st_mode == SRS_TX_BW_FANOUT ||
3977             mac_srs->srs_tx.st_mode == SRS_TX_AGGR ||
3978             mac_srs->srs_tx.st_mode == SRS_TX_BW_AGGR);
3979 
3980         if (ringp->s_ring_type & ST_RING_WORKER_ONLY) {
3981                 /* Serialization mode */
3982 
3983                 mutex_enter(&ringp->s_ring_lock);
3984                 if (ringp->s_ring_count > ringp->s_ring_tx_hiwat) {
3985                         cookie = mac_tx_sring_enqueue(ringp, mp_chain,
3986                             flag, ret_mp);
3987                         mutex_exit(&ringp->s_ring_lock);
3988                         return (cookie);
3989                 }
3990                 MAC_COUNT_CHAIN(mac_srs, mp_chain, tail, cnt, sz);
3991                 TX_SOFT_RING_ENQUEUE_CHAIN(ringp, mp_chain, tail, cnt, sz);
3992                 if (ringp->s_ring_state & (S_RING_BLOCK | S_RING_PROC)) {
3993                         /*
3994                          * If ring is blocked due to lack of Tx
3995                          * descs, just return. Worker thread
3996                          * will get scheduled when Tx desc's
3997                          * become available.
3998                          */
3999                         mutex_exit(&ringp->s_ring_lock);
4000                         return (cookie);
4001                 }
4002                 mac_soft_ring_worker_wakeup(ringp);
4003                 mutex_exit(&ringp->s_ring_lock);
4004                 return (cookie);
4005         } else {
4006                 /* Default fanout mode */
4007                 /*
4008                  * S_RING_BLOCKED is set when underlying NIC runs
4009                  * out of Tx descs and messages start getting
4010                  * queued. It won't get reset until
4011                  * tx_srs_drain() completely drains out the
4012                  * messages.
4013                  */
4014                 mac_tx_stats_t          stats;
4015 
4016                 if (ringp->s_ring_state & S_RING_ENQUEUED) {
4017                         /* Tx descs/resources not available */
4018                         mutex_enter(&ringp->s_ring_lock);
4019                         if (ringp->s_ring_state & S_RING_ENQUEUED) {
4020                                 cookie = mac_tx_sring_enqueue(ringp, mp_chain,
4021                                     flag, ret_mp);
4022                                 mutex_exit(&ringp->s_ring_lock);
4023                                 return (cookie);
4024                         }
4025                         /*
4026                          * While we were computing mblk count, the
4027                          * flow control condition got relieved.
4028                          * Continue with the transmission.
4029                          */
4030                         mutex_exit(&ringp->s_ring_lock);
4031                 }
4032 
4033                 mp_chain = mac_tx_send(ringp->s_ring_tx_arg1,
4034                     ringp->s_ring_tx_arg2, mp_chain, &stats);
4035 
4036                 /*
4037                  * Multiple threads could be here sending packets.
4038                  * Under such conditions, it is not possible to
4039                  * automically set S_RING_BLOCKED bit to indicate
4040                  * out of tx desc condition. To atomically set
4041                  * this, we queue the returned packet and do
4042                  * the setting of S_RING_BLOCKED in
4043                  * mac_tx_soft_ring_drain().
4044                  */
4045                 if (mp_chain != NULL) {
4046                         mutex_enter(&ringp->s_ring_lock);
4047                         cookie =
4048                             mac_tx_sring_enqueue(ringp, mp_chain, flag, ret_mp);
4049                         mutex_exit(&ringp->s_ring_lock);
4050                         return (cookie);
4051                 }
4052                 SRS_TX_STATS_UPDATE(mac_srs, &stats);
4053                 SOFTRING_TX_STATS_UPDATE(ringp, &stats);
4054 
4055                 return (NULL);
4056         }
4057 }