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 /*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25 * Copyright (c) 2011 Joyent, Inc. All rights reserved.
26 * Copyright (c) 2014 by Delphix. All rights reserved.
27 */
28
29 /* This file contains all TCP input processing functions. */
30
31 #include <sys/types.h>
32 #include <sys/stream.h>
33 #include <sys/strsun.h>
34 #include <sys/strsubr.h>
35 #include <sys/stropts.h>
36 #include <sys/strlog.h>
37 #define _SUN_TPI_VERSION 2
38 #include <sys/tihdr.h>
39 #include <sys/suntpi.h>
40 #include <sys/xti_inet.h>
41 #include <sys/squeue_impl.h>
42 #include <sys/squeue.h>
43 #include <sys/tsol/tnet.h>
44
45 #include <inet/common.h>
46 #include <inet/ip.h>
47 #include <inet/tcp.h>
48 #include <inet/tcp_impl.h>
49 #include <inet/tcp_cluster.h>
50 #include <inet/proto_set.h>
51 #include <inet/ipsec_impl.h>
52
53 /*
54 * RFC1323-recommended phrasing of TSTAMP option, for easier parsing
55 */
56
57 #ifdef _BIG_ENDIAN
58 #define TCPOPT_NOP_NOP_TSTAMP ((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | \
59 (TCPOPT_TSTAMP << 8) | 10)
60 #else
61 #define TCPOPT_NOP_NOP_TSTAMP ((10 << 24) | (TCPOPT_TSTAMP << 16) | \
62 (TCPOPT_NOP << 8) | TCPOPT_NOP)
63 #endif
64
65 /*
66 * Flags returned from tcp_parse_options.
67 */
68 #define TCP_OPT_MSS_PRESENT 1
69 #define TCP_OPT_WSCALE_PRESENT 2
70 #define TCP_OPT_TSTAMP_PRESENT 4
71 #define TCP_OPT_SACK_OK_PRESENT 8
72 #define TCP_OPT_SACK_PRESENT 16
73
74 /*
75 * PAWS needs a timer for 24 days. This is the number of ticks in 24 days
76 */
77 #define PAWS_TIMEOUT ((clock_t)(24*24*60*60*hz))
78
79 /*
80 * Since tcp_listener is not cleared atomically with tcp_detached
81 * being cleared we need this extra bit to tell a detached connection
82 * apart from one that is in the process of being accepted.
83 */
84 #define TCP_IS_DETACHED_NONEAGER(tcp) \
85 (TCP_IS_DETACHED(tcp) && \
86 (!(tcp)->tcp_hard_binding))
87
88 /*
89 * Steps to do when a tcp_t moves to TIME-WAIT state.
90 *
91 * This connection is done, we don't need to account for it. Decrement
92 * the listener connection counter if needed.
93 *
94 * Decrement the connection counter of the stack. Note that this counter
95 * is per CPU. So the total number of connections in a stack is the sum of all
96 * of them. Since there is no lock for handling all of them exclusively, the
97 * resulting sum is only an approximation.
98 *
99 * Unconditionally clear the exclusive binding bit so this TIME-WAIT
100 * connection won't interfere with new ones.
101 *
102 * Start the TIME-WAIT timer. If upper layer has not closed the connection,
103 * the timer is handled within the context of this tcp_t. When the timer
104 * fires, tcp_clean_death() is called. If upper layer closes the connection
105 * during this period, tcp_time_wait_append() will be called to add this
106 * tcp_t to the global TIME-WAIT list. Note that this means that the
107 * actual wait time in TIME-WAIT state will be longer than the
108 * tcps_time_wait_interval since the period before upper layer closes the
109 * connection is not accounted for when tcp_time_wait_append() is called.
110 *
111 * If uppser layer has closed the connection, call tcp_time_wait_append()
112 * directly.
113 *
114 */
115 #define SET_TIME_WAIT(tcps, tcp, connp) \
116 { \
117 (tcp)->tcp_state = TCPS_TIME_WAIT; \
118 if ((tcp)->tcp_listen_cnt != NULL) \
119 TCP_DECR_LISTEN_CNT(tcp); \
120 atomic_dec_64( \
121 (uint64_t *)&(tcps)->tcps_sc[CPU->cpu_seqid]->tcp_sc_conn_cnt); \
122 (connp)->conn_exclbind = 0; \
123 if (!TCP_IS_DETACHED(tcp)) { \
124 TCP_TIMER_RESTART(tcp, (tcps)->tcps_time_wait_interval); \
125 } else { \
126 tcp_time_wait_append(tcp); \
127 TCP_DBGSTAT(tcps, tcp_rput_time_wait); \
128 } \
129 }
130
131 /*
132 * If tcp_drop_ack_unsent_cnt is greater than 0, when TCP receives more
133 * than tcp_drop_ack_unsent_cnt number of ACKs which acknowledge unsent
134 * data, TCP will not respond with an ACK. RFC 793 requires that
135 * TCP responds with an ACK for such a bogus ACK. By not following
136 * the RFC, we prevent TCP from getting into an ACK storm if somehow
137 * an attacker successfully spoofs an acceptable segment to our
138 * peer; or when our peer is "confused."
139 */
140 static uint32_t tcp_drop_ack_unsent_cnt = 10;
141
142 /*
143 * To protect TCP against attacker using a small window and requesting
144 * large amount of data (DoS attack by conuming memory), TCP checks the
145 * window advertised in the last ACK of the 3-way handshake. TCP uses
146 * the tcp_mss (the size of one packet) value for comparion. The window
147 * should be larger than tcp_mss. But while a sane TCP should advertise
148 * a receive window larger than or equal to 4*MSS to avoid stop and go
149 * tarrfic, not all TCP stacks do that. This is especially true when
150 * tcp_mss is a big value.
151 *
152 * To work around this issue, an additional fixed value for comparison
153 * is also used. If the advertised window is smaller than both tcp_mss
154 * and tcp_init_wnd_chk, the ACK is considered as invalid. So for large
155 * tcp_mss value (say, 8K), a window larger than tcp_init_wnd_chk but
156 * smaller than 8K is considered to be OK.
157 */
158 static uint32_t tcp_init_wnd_chk = 4096;
159
160 /* Process ICMP source quench message or not. */
161 static boolean_t tcp_icmp_source_quench = B_FALSE;
162
163 static boolean_t tcp_outbound_squeue_switch = B_FALSE;
164
165 static mblk_t *tcp_conn_create_v4(conn_t *, conn_t *, mblk_t *,
166 ip_recv_attr_t *);
167 static mblk_t *tcp_conn_create_v6(conn_t *, conn_t *, mblk_t *,
168 ip_recv_attr_t *);
169 static boolean_t tcp_drop_q0(tcp_t *);
170 static void tcp_icmp_error_ipv6(tcp_t *, mblk_t *, ip_recv_attr_t *);
171 static mblk_t *tcp_input_add_ancillary(tcp_t *, mblk_t *, ip_pkt_t *,
172 ip_recv_attr_t *);
173 static void tcp_input_listener(void *, mblk_t *, void *, ip_recv_attr_t *);
174 static int tcp_parse_options(tcpha_t *, tcp_opt_t *);
175 static void tcp_process_options(tcp_t *, tcpha_t *);
176 static mblk_t *tcp_reass(tcp_t *, mblk_t *, uint32_t);
177 static void tcp_reass_elim_overlap(tcp_t *, mblk_t *);
178 static void tcp_rsrv_input(void *, mblk_t *, void *, ip_recv_attr_t *);
179 static void tcp_set_rto(tcp_t *, time_t);
180 static void tcp_setcred_data(mblk_t *, ip_recv_attr_t *);
181
182 /*
183 * Set the MSS associated with a particular tcp based on its current value,
184 * and a new one passed in. Observe minimums and maximums, and reset other
185 * state variables that we want to view as multiples of MSS.
186 *
187 * The value of MSS could be either increased or descreased.
188 */
189 void
190 tcp_mss_set(tcp_t *tcp, uint32_t mss)
191 {
192 uint32_t mss_max;
193 tcp_stack_t *tcps = tcp->tcp_tcps;
194 conn_t *connp = tcp->tcp_connp;
195
196 if (connp->conn_ipversion == IPV4_VERSION)
197 mss_max = tcps->tcps_mss_max_ipv4;
198 else
199 mss_max = tcps->tcps_mss_max_ipv6;
200
201 if (mss < tcps->tcps_mss_min)
202 mss = tcps->tcps_mss_min;
203 if (mss > mss_max)
204 mss = mss_max;
205 /*
206 * Unless naglim has been set by our client to
207 * a non-mss value, force naglim to track mss.
208 * This can help to aggregate small writes.
209 */
210 if (mss < tcp->tcp_naglim || tcp->tcp_mss == tcp->tcp_naglim)
211 tcp->tcp_naglim = mss;
212 /*
213 * TCP should be able to buffer at least 4 MSS data for obvious
214 * performance reason.
215 */
216 if ((mss << 2) > connp->conn_sndbuf)
217 connp->conn_sndbuf = mss << 2;
218
219 /*
220 * Set the send lowater to at least twice of MSS.
221 */
222 if ((mss << 1) > connp->conn_sndlowat)
223 connp->conn_sndlowat = mss << 1;
224
225 /*
226 * Update tcp_cwnd according to the new value of MSS. Keep the
227 * previous ratio to preserve the transmit rate.
228 */
229 tcp->tcp_cwnd = (tcp->tcp_cwnd / tcp->tcp_mss) * mss;
230 tcp->tcp_cwnd_cnt = 0;
231
232 tcp->tcp_mss = mss;
233 (void) tcp_maxpsz_set(tcp, B_TRUE);
234 }
235
236 /*
237 * Extract option values from a tcp header. We put any found values into the
238 * tcpopt struct and return a bitmask saying which options were found.
239 */
240 static int
241 tcp_parse_options(tcpha_t *tcpha, tcp_opt_t *tcpopt)
242 {
243 uchar_t *endp;
244 int len;
245 uint32_t mss;
246 uchar_t *up = (uchar_t *)tcpha;
247 int found = 0;
248 int32_t sack_len;
249 tcp_seq sack_begin, sack_end;
250 tcp_t *tcp;
251
252 endp = up + TCP_HDR_LENGTH(tcpha);
253 up += TCP_MIN_HEADER_LENGTH;
254 while (up < endp) {
255 len = endp - up;
256 switch (*up) {
257 case TCPOPT_EOL:
258 break;
259
260 case TCPOPT_NOP:
261 up++;
262 continue;
263
264 case TCPOPT_MAXSEG:
265 if (len < TCPOPT_MAXSEG_LEN ||
266 up[1] != TCPOPT_MAXSEG_LEN)
267 break;
268
269 mss = BE16_TO_U16(up+2);
270 /* Caller must handle tcp_mss_min and tcp_mss_max_* */
271 tcpopt->tcp_opt_mss = mss;
272 found |= TCP_OPT_MSS_PRESENT;
273
274 up += TCPOPT_MAXSEG_LEN;
275 continue;
276
277 case TCPOPT_WSCALE:
278 if (len < TCPOPT_WS_LEN || up[1] != TCPOPT_WS_LEN)
279 break;
280
281 if (up[2] > TCP_MAX_WINSHIFT)
282 tcpopt->tcp_opt_wscale = TCP_MAX_WINSHIFT;
283 else
284 tcpopt->tcp_opt_wscale = up[2];
285 found |= TCP_OPT_WSCALE_PRESENT;
286
287 up += TCPOPT_WS_LEN;
288 continue;
289
290 case TCPOPT_SACK_PERMITTED:
291 if (len < TCPOPT_SACK_OK_LEN ||
292 up[1] != TCPOPT_SACK_OK_LEN)
293 break;
294 found |= TCP_OPT_SACK_OK_PRESENT;
295 up += TCPOPT_SACK_OK_LEN;
296 continue;
297
298 case TCPOPT_SACK:
299 if (len <= 2 || up[1] <= 2 || len < up[1])
300 break;
301
302 /* If TCP is not interested in SACK blks... */
303 if ((tcp = tcpopt->tcp) == NULL) {
304 up += up[1];
305 continue;
306 }
307 sack_len = up[1] - TCPOPT_HEADER_LEN;
308 up += TCPOPT_HEADER_LEN;
309
310 /*
311 * If the list is empty, allocate one and assume
312 * nothing is sack'ed.
313 */
314 if (tcp->tcp_notsack_list == NULL) {
315 tcp_notsack_update(&(tcp->tcp_notsack_list),
316 tcp->tcp_suna, tcp->tcp_snxt,
317 &(tcp->tcp_num_notsack_blk),
318 &(tcp->tcp_cnt_notsack_list));
319
320 /*
321 * Make sure tcp_notsack_list is not NULL.
322 * This happens when kmem_alloc(KM_NOSLEEP)
323 * returns NULL.
324 */
325 if (tcp->tcp_notsack_list == NULL) {
326 up += sack_len;
327 continue;
328 }
329 tcp->tcp_fack = tcp->tcp_suna;
330 }
331
332 while (sack_len > 0) {
333 if (up + 8 > endp) {
334 up = endp;
335 break;
336 }
337 sack_begin = BE32_TO_U32(up);
338 up += 4;
339 sack_end = BE32_TO_U32(up);
340 up += 4;
341 sack_len -= 8;
342 /*
343 * Bounds checking. Make sure the SACK
344 * info is within tcp_suna and tcp_snxt.
345 * If this SACK blk is out of bound, ignore
346 * it but continue to parse the following
347 * blks.
348 */
349 if (SEQ_LEQ(sack_end, sack_begin) ||
350 SEQ_LT(sack_begin, tcp->tcp_suna) ||
351 SEQ_GT(sack_end, tcp->tcp_snxt)) {
352 continue;
353 }
354 tcp_notsack_insert(&(tcp->tcp_notsack_list),
355 sack_begin, sack_end,
356 &(tcp->tcp_num_notsack_blk),
357 &(tcp->tcp_cnt_notsack_list));
358 if (SEQ_GT(sack_end, tcp->tcp_fack)) {
359 tcp->tcp_fack = sack_end;
360 }
361 }
362 found |= TCP_OPT_SACK_PRESENT;
363 continue;
364
365 case TCPOPT_TSTAMP:
366 if (len < TCPOPT_TSTAMP_LEN ||
367 up[1] != TCPOPT_TSTAMP_LEN)
368 break;
369
370 tcpopt->tcp_opt_ts_val = BE32_TO_U32(up+2);
371 tcpopt->tcp_opt_ts_ecr = BE32_TO_U32(up+6);
372
373 found |= TCP_OPT_TSTAMP_PRESENT;
374
375 up += TCPOPT_TSTAMP_LEN;
376 continue;
377
378 default:
379 if (len <= 1 || len < (int)up[1] || up[1] == 0)
380 break;
381 up += up[1];
382 continue;
383 }
384 break;
385 }
386 return (found);
387 }
388
389 /*
390 * Process all TCP option in SYN segment. Note that this function should
391 * be called after tcp_set_destination() is called so that the necessary info
392 * from IRE is already set in the tcp structure.
393 *
394 * This function sets up the correct tcp_mss value according to the
395 * MSS option value and our header size. It also sets up the window scale
396 * and timestamp values, and initialize SACK info blocks. But it does not
397 * change receive window size after setting the tcp_mss value. The caller
398 * should do the appropriate change.
399 */
400 static void
401 tcp_process_options(tcp_t *tcp, tcpha_t *tcpha)
402 {
403 int options;
404 tcp_opt_t tcpopt;
405 uint32_t mss_max;
406 char *tmp_tcph;
407 tcp_stack_t *tcps = tcp->tcp_tcps;
408 conn_t *connp = tcp->tcp_connp;
409
410 tcpopt.tcp = NULL;
411 options = tcp_parse_options(tcpha, &tcpopt);
412
413 /*
414 * Process MSS option. Note that MSS option value does not account
415 * for IP or TCP options. This means that it is equal to MTU - minimum
416 * IP+TCP header size, which is 40 bytes for IPv4 and 60 bytes for
417 * IPv6.
418 */
419 if (!(options & TCP_OPT_MSS_PRESENT)) {
420 if (connp->conn_ipversion == IPV4_VERSION)
421 tcpopt.tcp_opt_mss = tcps->tcps_mss_def_ipv4;
422 else
423 tcpopt.tcp_opt_mss = tcps->tcps_mss_def_ipv6;
424 } else {
425 if (connp->conn_ipversion == IPV4_VERSION)
426 mss_max = tcps->tcps_mss_max_ipv4;
427 else
428 mss_max = tcps->tcps_mss_max_ipv6;
429 if (tcpopt.tcp_opt_mss < tcps->tcps_mss_min)
430 tcpopt.tcp_opt_mss = tcps->tcps_mss_min;
431 else if (tcpopt.tcp_opt_mss > mss_max)
432 tcpopt.tcp_opt_mss = mss_max;
433 }
434
435 /* Process Window Scale option. */
436 if (options & TCP_OPT_WSCALE_PRESENT) {
437 tcp->tcp_snd_ws = tcpopt.tcp_opt_wscale;
438 tcp->tcp_snd_ws_ok = B_TRUE;
439 } else {
440 tcp->tcp_snd_ws = B_FALSE;
441 tcp->tcp_snd_ws_ok = B_FALSE;
442 tcp->tcp_rcv_ws = B_FALSE;
443 }
444
445 /* Process Timestamp option. */
446 if ((options & TCP_OPT_TSTAMP_PRESENT) &&
447 (tcp->tcp_snd_ts_ok || TCP_IS_DETACHED(tcp))) {
448 tmp_tcph = (char *)tcp->tcp_tcpha;
449
450 tcp->tcp_snd_ts_ok = B_TRUE;
451 tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val;
452 tcp->tcp_last_rcv_lbolt = ddi_get_lbolt64();
453 ASSERT(OK_32PTR(tmp_tcph));
454 ASSERT(connp->conn_ht_ulp_len == TCP_MIN_HEADER_LENGTH);
455
456 /* Fill in our template header with basic timestamp option. */
457 tmp_tcph += connp->conn_ht_ulp_len;
458 tmp_tcph[0] = TCPOPT_NOP;
459 tmp_tcph[1] = TCPOPT_NOP;
460 tmp_tcph[2] = TCPOPT_TSTAMP;
461 tmp_tcph[3] = TCPOPT_TSTAMP_LEN;
462 connp->conn_ht_iphc_len += TCPOPT_REAL_TS_LEN;
463 connp->conn_ht_ulp_len += TCPOPT_REAL_TS_LEN;
464 tcp->tcp_tcpha->tha_offset_and_reserved += (3 << 4);
465 } else {
466 tcp->tcp_snd_ts_ok = B_FALSE;
467 }
468
469 /*
470 * Process SACK options. If SACK is enabled for this connection,
471 * then allocate the SACK info structure. Note the following ways
472 * when tcp_snd_sack_ok is set to true.
473 *
474 * For active connection: in tcp_set_destination() called in
475 * tcp_connect().
476 *
477 * For passive connection: in tcp_set_destination() called in
478 * tcp_input_listener().
479 *
480 * That's the reason why the extra TCP_IS_DETACHED() check is there.
481 * That check makes sure that if we did not send a SACK OK option,
482 * we will not enable SACK for this connection even though the other
483 * side sends us SACK OK option. For active connection, the SACK
484 * info structure has already been allocated. So we need to free
485 * it if SACK is disabled.
486 */
487 if ((options & TCP_OPT_SACK_OK_PRESENT) &&
488 (tcp->tcp_snd_sack_ok ||
489 (tcps->tcps_sack_permitted != 0 && TCP_IS_DETACHED(tcp)))) {
490 ASSERT(tcp->tcp_num_sack_blk == 0);
491 ASSERT(tcp->tcp_notsack_list == NULL);
492
493 tcp->tcp_snd_sack_ok = B_TRUE;
494 if (tcp->tcp_snd_ts_ok) {
495 tcp->tcp_max_sack_blk = 3;
496 } else {
497 tcp->tcp_max_sack_blk = 4;
498 }
499 } else if (tcp->tcp_snd_sack_ok) {
500 /*
501 * Resetting tcp_snd_sack_ok to B_FALSE so that
502 * no SACK info will be used for this
503 * connection. This assumes that SACK usage
504 * permission is negotiated. This may need
505 * to be changed once this is clarified.
506 */
507 ASSERT(tcp->tcp_num_sack_blk == 0);
508 ASSERT(tcp->tcp_notsack_list == NULL);
509 tcp->tcp_snd_sack_ok = B_FALSE;
510 }
511
512 /*
513 * Now we know the exact TCP/IP header length, subtract
514 * that from tcp_mss to get our side's MSS.
515 */
516 tcp->tcp_mss -= connp->conn_ht_iphc_len;
517
518 /*
519 * Here we assume that the other side's header size will be equal to
520 * our header size. We calculate the real MSS accordingly. Need to
521 * take into additional stuffs IPsec puts in.
522 *
523 * Real MSS = Opt.MSS - (our TCP/IP header - min TCP/IP header)
524 */
525 tcpopt.tcp_opt_mss -= connp->conn_ht_iphc_len +
526 tcp->tcp_ipsec_overhead -
527 ((connp->conn_ipversion == IPV4_VERSION ?
528 IP_SIMPLE_HDR_LENGTH : IPV6_HDR_LEN) + TCP_MIN_HEADER_LENGTH);
529
530 /*
531 * Set MSS to the smaller one of both ends of the connection.
532 * We should not have called tcp_mss_set() before, but our
533 * side of the MSS should have been set to a proper value
534 * by tcp_set_destination(). tcp_mss_set() will also set up the
535 * STREAM head parameters properly.
536 *
537 * If we have a larger-than-16-bit window but the other side
538 * didn't want to do window scale, tcp_rwnd_set() will take
539 * care of that.
540 */
541 tcp_mss_set(tcp, MIN(tcpopt.tcp_opt_mss, tcp->tcp_mss));
542
543 /*
544 * Initialize tcp_cwnd value. After tcp_mss_set(), tcp_mss has been
545 * updated properly.
546 */
547 TCP_SET_INIT_CWND(tcp, tcp->tcp_mss, tcps->tcps_slow_start_initial);
548 }
549
550 /*
551 * Add a new piece to the tcp reassembly queue. If the gap at the beginning
552 * is filled, return as much as we can. The message passed in may be
553 * multi-part, chained using b_cont. "start" is the starting sequence
554 * number for this piece.
555 */
556 static mblk_t *
557 tcp_reass(tcp_t *tcp, mblk_t *mp, uint32_t start)
558 {
559 uint32_t end;
560 mblk_t *mp1;
561 mblk_t *mp2;
562 mblk_t *next_mp;
563 uint32_t u1;
564 tcp_stack_t *tcps = tcp->tcp_tcps;
565
566
567 /* Walk through all the new pieces. */
568 do {
569 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
570 (uintptr_t)INT_MAX);
571 end = start + (int)(mp->b_wptr - mp->b_rptr);
572 next_mp = mp->b_cont;
573 if (start == end) {
574 /* Empty. Blast it. */
575 freeb(mp);
576 continue;
577 }
578 mp->b_cont = NULL;
579 TCP_REASS_SET_SEQ(mp, start);
580 TCP_REASS_SET_END(mp, end);
581 mp1 = tcp->tcp_reass_tail;
582 if (!mp1) {
583 tcp->tcp_reass_tail = mp;
584 tcp->tcp_reass_head = mp;
585 TCPS_BUMP_MIB(tcps, tcpInDataUnorderSegs);
586 TCPS_UPDATE_MIB(tcps, tcpInDataUnorderBytes,
587 end - start);
588 continue;
589 }
590 /* New stuff completely beyond tail? */
591 if (SEQ_GEQ(start, TCP_REASS_END(mp1))) {
592 /* Link it on end. */
593 mp1->b_cont = mp;
594 tcp->tcp_reass_tail = mp;
595 TCPS_BUMP_MIB(tcps, tcpInDataUnorderSegs);
596 TCPS_UPDATE_MIB(tcps, tcpInDataUnorderBytes,
597 end - start);
598 continue;
599 }
600 mp1 = tcp->tcp_reass_head;
601 u1 = TCP_REASS_SEQ(mp1);
602 /* New stuff at the front? */
603 if (SEQ_LT(start, u1)) {
604 /* Yes... Check for overlap. */
605 mp->b_cont = mp1;
606 tcp->tcp_reass_head = mp;
607 tcp_reass_elim_overlap(tcp, mp);
608 continue;
609 }
610 /*
611 * The new piece fits somewhere between the head and tail.
612 * We find our slot, where mp1 precedes us and mp2 trails.
613 */
614 for (; (mp2 = mp1->b_cont) != NULL; mp1 = mp2) {
615 u1 = TCP_REASS_SEQ(mp2);
616 if (SEQ_LEQ(start, u1))
617 break;
618 }
619 /* Link ourselves in */
620 mp->b_cont = mp2;
621 mp1->b_cont = mp;
622
623 /* Trim overlap with following mblk(s) first */
624 tcp_reass_elim_overlap(tcp, mp);
625
626 /* Trim overlap with preceding mblk */
627 tcp_reass_elim_overlap(tcp, mp1);
628
629 } while (start = end, mp = next_mp);
630 mp1 = tcp->tcp_reass_head;
631 /* Anything ready to go? */
632 if (TCP_REASS_SEQ(mp1) != tcp->tcp_rnxt)
633 return (NULL);
634 /* Eat what we can off the queue */
635 for (;;) {
636 mp = mp1->b_cont;
637 end = TCP_REASS_END(mp1);
638 TCP_REASS_SET_SEQ(mp1, 0);
639 TCP_REASS_SET_END(mp1, 0);
640 if (!mp) {
641 tcp->tcp_reass_tail = NULL;
642 break;
643 }
644 if (end != TCP_REASS_SEQ(mp)) {
645 mp1->b_cont = NULL;
646 break;
647 }
648 mp1 = mp;
649 }
650 mp1 = tcp->tcp_reass_head;
651 tcp->tcp_reass_head = mp;
652 return (mp1);
653 }
654
655 /* Eliminate any overlap that mp may have over later mblks */
656 static void
657 tcp_reass_elim_overlap(tcp_t *tcp, mblk_t *mp)
658 {
659 uint32_t end;
660 mblk_t *mp1;
661 uint32_t u1;
662 tcp_stack_t *tcps = tcp->tcp_tcps;
663
664 end = TCP_REASS_END(mp);
665 while ((mp1 = mp->b_cont) != NULL) {
666 u1 = TCP_REASS_SEQ(mp1);
667 if (!SEQ_GT(end, u1))
668 break;
669 if (!SEQ_GEQ(end, TCP_REASS_END(mp1))) {
670 mp->b_wptr -= end - u1;
671 TCP_REASS_SET_END(mp, u1);
672 TCPS_BUMP_MIB(tcps, tcpInDataPartDupSegs);
673 TCPS_UPDATE_MIB(tcps, tcpInDataPartDupBytes,
674 end - u1);
675 break;
676 }
677 mp->b_cont = mp1->b_cont;
678 TCP_REASS_SET_SEQ(mp1, 0);
679 TCP_REASS_SET_END(mp1, 0);
680 freeb(mp1);
681 TCPS_BUMP_MIB(tcps, tcpInDataDupSegs);
682 TCPS_UPDATE_MIB(tcps, tcpInDataDupBytes, end - u1);
683 }
684 if (!mp1)
685 tcp->tcp_reass_tail = mp;
686 }
687
688 /*
689 * This function does PAWS protection check. Returns B_TRUE if the
690 * segment passes the PAWS test, else returns B_FALSE.
691 */
692 boolean_t
693 tcp_paws_check(tcp_t *tcp, tcpha_t *tcpha, tcp_opt_t *tcpoptp)
694 {
695 uint8_t flags;
696 int options;
697 uint8_t *up;
698 conn_t *connp = tcp->tcp_connp;
699
700 flags = (unsigned int)tcpha->tha_flags & 0xFF;
701 /*
702 * If timestamp option is aligned nicely, get values inline,
703 * otherwise call general routine to parse. Only do that
704 * if timestamp is the only option.
705 */
706 if (TCP_HDR_LENGTH(tcpha) == (uint32_t)TCP_MIN_HEADER_LENGTH +
707 TCPOPT_REAL_TS_LEN &&
708 OK_32PTR((up = ((uint8_t *)tcpha) +
709 TCP_MIN_HEADER_LENGTH)) &&
710 *(uint32_t *)up == TCPOPT_NOP_NOP_TSTAMP) {
711 tcpoptp->tcp_opt_ts_val = ABE32_TO_U32((up+4));
712 tcpoptp->tcp_opt_ts_ecr = ABE32_TO_U32((up+8));
713
714 options = TCP_OPT_TSTAMP_PRESENT;
715 } else {
716 if (tcp->tcp_snd_sack_ok) {
717 tcpoptp->tcp = tcp;
718 } else {
719 tcpoptp->tcp = NULL;
720 }
721 options = tcp_parse_options(tcpha, tcpoptp);
722 }
723
724 if (options & TCP_OPT_TSTAMP_PRESENT) {
725 /*
726 * Do PAWS per RFC 1323 section 4.2. Accept RST
727 * regardless of the timestamp, page 18 RFC 1323.bis.
728 */
729 if ((flags & TH_RST) == 0 &&
730 TSTMP_LT(tcpoptp->tcp_opt_ts_val,
731 tcp->tcp_ts_recent)) {
732 if (LBOLT_FASTPATH64 <
733 (tcp->tcp_last_rcv_lbolt + PAWS_TIMEOUT)) {
734 /* This segment is not acceptable. */
735 return (B_FALSE);
736 } else {
737 /*
738 * Connection has been idle for
739 * too long. Reset the timestamp
740 * and assume the segment is valid.
741 */
742 tcp->tcp_ts_recent =
743 tcpoptp->tcp_opt_ts_val;
744 }
745 }
746 } else {
747 /*
748 * If we don't get a timestamp on every packet, we
749 * figure we can't really trust 'em, so we stop sending
750 * and parsing them.
751 */
752 tcp->tcp_snd_ts_ok = B_FALSE;
753
754 connp->conn_ht_iphc_len -= TCPOPT_REAL_TS_LEN;
755 connp->conn_ht_ulp_len -= TCPOPT_REAL_TS_LEN;
756 tcp->tcp_tcpha->tha_offset_and_reserved -= (3 << 4);
757 /*
758 * Adjust the tcp_mss and tcp_cwnd accordingly. We avoid
759 * doing a slow start here so as to not to lose on the
760 * transfer rate built up so far.
761 */
762 tcp_mss_set(tcp, tcp->tcp_mss + TCPOPT_REAL_TS_LEN);
763 if (tcp->tcp_snd_sack_ok)
764 tcp->tcp_max_sack_blk = 4;
765 }
766 return (B_TRUE);
767 }
768
769 /*
770 * Defense for the SYN attack -
771 * 1. When q0 is full, drop from the tail (tcp_eager_prev_drop_q0) the oldest
772 * one from the list of droppable eagers. This list is a subset of q0.
773 * see comments before the definition of MAKE_DROPPABLE().
774 * 2. Don't drop a SYN request before its first timeout. This gives every
775 * request at least til the first timeout to complete its 3-way handshake.
776 * 3. Maintain tcp_syn_rcvd_timeout as an accurate count of how many
777 * requests currently on the queue that has timed out. This will be used
778 * as an indicator of whether an attack is under way, so that appropriate
779 * actions can be taken. (It's incremented in tcp_timer() and decremented
780 * either when eager goes into ESTABLISHED, or gets freed up.)
781 * 4. The current threshold is - # of timeout > q0len/4 => SYN alert on
782 * # of timeout drops back to <= q0len/32 => SYN alert off
783 */
784 static boolean_t
785 tcp_drop_q0(tcp_t *tcp)
786 {
787 tcp_t *eager;
788 mblk_t *mp;
789 tcp_stack_t *tcps = tcp->tcp_tcps;
790
791 ASSERT(MUTEX_HELD(&tcp->tcp_eager_lock));
792 ASSERT(tcp->tcp_eager_next_q0 != tcp->tcp_eager_prev_q0);
793
794 /* Pick oldest eager from the list of droppable eagers */
795 eager = tcp->tcp_eager_prev_drop_q0;
796
797 /* If list is empty. return B_FALSE */
798 if (eager == tcp) {
799 return (B_FALSE);
800 }
801
802 /* If allocated, the mp will be freed in tcp_clean_death_wrapper() */
803 if ((mp = allocb(0, BPRI_HI)) == NULL)
804 return (B_FALSE);
805
806 /*
807 * Take this eager out from the list of droppable eagers since we are
808 * going to drop it.
809 */
810 MAKE_UNDROPPABLE(eager);
811
812 if (tcp->tcp_connp->conn_debug) {
813 (void) strlog(TCP_MOD_ID, 0, 3, SL_TRACE,
814 "tcp_drop_q0: listen half-open queue (max=%d) overflow"
815 " (%d pending) on %s, drop one", tcps->tcps_conn_req_max_q0,
816 tcp->tcp_conn_req_cnt_q0,
817 tcp_display(tcp, NULL, DISP_PORT_ONLY));
818 }
819
820 TCPS_BUMP_MIB(tcps, tcpHalfOpenDrop);
821
822 /* Put a reference on the conn as we are enqueueing it in the sqeue */
823 CONN_INC_REF(eager->tcp_connp);
824
825 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
826 tcp_clean_death_wrapper, eager->tcp_connp, NULL,
827 SQ_FILL, SQTAG_TCP_DROP_Q0);
828
829 return (B_TRUE);
830 }
831
832 /*
833 * Handle a SYN on an AF_INET6 socket; can be either IPv4 or IPv6
834 */
835 static mblk_t *
836 tcp_conn_create_v6(conn_t *lconnp, conn_t *connp, mblk_t *mp,
837 ip_recv_attr_t *ira)
838 {
839 tcp_t *ltcp = lconnp->conn_tcp;
840 tcp_t *tcp = connp->conn_tcp;
841 mblk_t *tpi_mp;
842 ipha_t *ipha;
843 ip6_t *ip6h;
844 sin6_t sin6;
845 uint_t ifindex = ira->ira_ruifindex;
846 tcp_stack_t *tcps = tcp->tcp_tcps;
847
848 if (ira->ira_flags & IRAF_IS_IPV4) {
849 ipha = (ipha_t *)mp->b_rptr;
850
851 connp->conn_ipversion = IPV4_VERSION;
852 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_dst, &connp->conn_laddr_v6);
853 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_src, &connp->conn_faddr_v6);
854 connp->conn_saddr_v6 = connp->conn_laddr_v6;
855
856 sin6 = sin6_null;
857 sin6.sin6_addr = connp->conn_faddr_v6;
858 sin6.sin6_port = connp->conn_fport;
859 sin6.sin6_family = AF_INET6;
860 sin6.__sin6_src_id = ip_srcid_find_addr(&connp->conn_laddr_v6,
861 IPCL_ZONEID(lconnp), tcps->tcps_netstack);
862
863 if (connp->conn_recv_ancillary.crb_recvdstaddr) {
864 sin6_t sin6d;
865
866 sin6d = sin6_null;
867 sin6d.sin6_addr = connp->conn_laddr_v6;
868 sin6d.sin6_port = connp->conn_lport;
869 sin6d.sin6_family = AF_INET;
870 tpi_mp = mi_tpi_extconn_ind(NULL,
871 (char *)&sin6d, sizeof (sin6_t),
872 (char *)&tcp,
873 (t_scalar_t)sizeof (intptr_t),
874 (char *)&sin6d, sizeof (sin6_t),
875 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
876 } else {
877 tpi_mp = mi_tpi_conn_ind(NULL,
878 (char *)&sin6, sizeof (sin6_t),
879 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
880 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
881 }
882 } else {
883 ip6h = (ip6_t *)mp->b_rptr;
884
885 connp->conn_ipversion = IPV6_VERSION;
886 connp->conn_laddr_v6 = ip6h->ip6_dst;
887 connp->conn_faddr_v6 = ip6h->ip6_src;
888 connp->conn_saddr_v6 = connp->conn_laddr_v6;
889
890 sin6 = sin6_null;
891 sin6.sin6_addr = connp->conn_faddr_v6;
892 sin6.sin6_port = connp->conn_fport;
893 sin6.sin6_family = AF_INET6;
894 sin6.sin6_flowinfo = ip6h->ip6_vcf & ~IPV6_VERS_AND_FLOW_MASK;
895 sin6.__sin6_src_id = ip_srcid_find_addr(&connp->conn_laddr_v6,
896 IPCL_ZONEID(lconnp), tcps->tcps_netstack);
897
898 if (IN6_IS_ADDR_LINKSCOPE(&ip6h->ip6_src)) {
899 /* Pass up the scope_id of remote addr */
900 sin6.sin6_scope_id = ifindex;
901 } else {
902 sin6.sin6_scope_id = 0;
903 }
904 if (connp->conn_recv_ancillary.crb_recvdstaddr) {
905 sin6_t sin6d;
906
907 sin6d = sin6_null;
908 sin6.sin6_addr = connp->conn_laddr_v6;
909 sin6d.sin6_port = connp->conn_lport;
910 sin6d.sin6_family = AF_INET6;
911 if (IN6_IS_ADDR_LINKSCOPE(&connp->conn_laddr_v6))
912 sin6d.sin6_scope_id = ifindex;
913
914 tpi_mp = mi_tpi_extconn_ind(NULL,
915 (char *)&sin6d, sizeof (sin6_t),
916 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
917 (char *)&sin6d, sizeof (sin6_t),
918 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
919 } else {
920 tpi_mp = mi_tpi_conn_ind(NULL,
921 (char *)&sin6, sizeof (sin6_t),
922 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
923 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
924 }
925 }
926
927 tcp->tcp_mss = tcps->tcps_mss_def_ipv6;
928 return (tpi_mp);
929 }
930
931 /* Handle a SYN on an AF_INET socket */
932 static mblk_t *
933 tcp_conn_create_v4(conn_t *lconnp, conn_t *connp, mblk_t *mp,
934 ip_recv_attr_t *ira)
935 {
936 tcp_t *ltcp = lconnp->conn_tcp;
937 tcp_t *tcp = connp->conn_tcp;
938 sin_t sin;
939 mblk_t *tpi_mp = NULL;
940 tcp_stack_t *tcps = tcp->tcp_tcps;
941 ipha_t *ipha;
942
943 ASSERT(ira->ira_flags & IRAF_IS_IPV4);
944 ipha = (ipha_t *)mp->b_rptr;
945
946 connp->conn_ipversion = IPV4_VERSION;
947 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_dst, &connp->conn_laddr_v6);
948 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_src, &connp->conn_faddr_v6);
949 connp->conn_saddr_v6 = connp->conn_laddr_v6;
950
951 sin = sin_null;
952 sin.sin_addr.s_addr = connp->conn_faddr_v4;
953 sin.sin_port = connp->conn_fport;
954 sin.sin_family = AF_INET;
955 if (lconnp->conn_recv_ancillary.crb_recvdstaddr) {
956 sin_t sind;
957
958 sind = sin_null;
959 sind.sin_addr.s_addr = connp->conn_laddr_v4;
960 sind.sin_port = connp->conn_lport;
961 sind.sin_family = AF_INET;
962 tpi_mp = mi_tpi_extconn_ind(NULL,
963 (char *)&sind, sizeof (sin_t), (char *)&tcp,
964 (t_scalar_t)sizeof (intptr_t), (char *)&sind,
965 sizeof (sin_t), (t_scalar_t)ltcp->tcp_conn_req_seqnum);
966 } else {
967 tpi_mp = mi_tpi_conn_ind(NULL,
968 (char *)&sin, sizeof (sin_t),
969 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
970 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
971 }
972
973 tcp->tcp_mss = tcps->tcps_mss_def_ipv4;
974 return (tpi_mp);
975 }
976
977 /*
978 * Called via squeue to get on to eager's perimeter. It sends a
979 * TH_RST if eager is in the fanout table. The listener wants the
980 * eager to disappear either by means of tcp_eager_blowoff() or
981 * tcp_eager_cleanup() being called. tcp_eager_kill() can also be
982 * called (via squeue) if the eager cannot be inserted in the
983 * fanout table in tcp_input_listener().
984 */
985 /* ARGSUSED */
986 void
987 tcp_eager_kill(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
988 {
989 conn_t *econnp = (conn_t *)arg;
990 tcp_t *eager = econnp->conn_tcp;
991 tcp_t *listener = eager->tcp_listener;
992
993 /*
994 * We could be called because listener is closing. Since
995 * the eager was using listener's queue's, we avoid
996 * using the listeners queues from now on.
997 */
998 ASSERT(eager->tcp_detached);
999 econnp->conn_rq = NULL;
1000 econnp->conn_wq = NULL;
1001
1002 /*
1003 * An eager's conn_fanout will be NULL if it's a duplicate
1004 * for an existing 4-tuples in the conn fanout table.
1005 * We don't want to send an RST out in such case.
1006 */
1007 if (econnp->conn_fanout != NULL && eager->tcp_state > TCPS_LISTEN) {
1008 tcp_xmit_ctl("tcp_eager_kill, can't wait",
1009 eager, eager->tcp_snxt, 0, TH_RST);
1010 }
1011
1012 /* We are here because listener wants this eager gone */
1013 if (listener != NULL) {
1014 mutex_enter(&listener->tcp_eager_lock);
1015 tcp_eager_unlink(eager);
1016 if (eager->tcp_tconnind_started) {
1017 /*
1018 * The eager has sent a conn_ind up to the
1019 * listener but listener decides to close
1020 * instead. We need to drop the extra ref
1021 * placed on eager in tcp_input_data() before
1022 * sending the conn_ind to listener.
1023 */
1024 CONN_DEC_REF(econnp);
1025 }
1026 mutex_exit(&listener->tcp_eager_lock);
1027 CONN_DEC_REF(listener->tcp_connp);
1028 }
1029
1030 if (eager->tcp_state != TCPS_CLOSED)
1031 tcp_close_detached(eager);
1032 }
1033
1034 /*
1035 * Reset any eager connection hanging off this listener marked
1036 * with 'seqnum' and then reclaim it's resources.
1037 */
1038 boolean_t
1039 tcp_eager_blowoff(tcp_t *listener, t_scalar_t seqnum)
1040 {
1041 tcp_t *eager;
1042 mblk_t *mp;
1043
1044 eager = listener;
1045 mutex_enter(&listener->tcp_eager_lock);
1046 do {
1047 eager = eager->tcp_eager_next_q;
1048 if (eager == NULL) {
1049 mutex_exit(&listener->tcp_eager_lock);
1050 return (B_FALSE);
1051 }
1052 } while (eager->tcp_conn_req_seqnum != seqnum);
1053
1054 if (eager->tcp_closemp_used) {
1055 mutex_exit(&listener->tcp_eager_lock);
1056 return (B_TRUE);
1057 }
1058 eager->tcp_closemp_used = B_TRUE;
1059 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1060 CONN_INC_REF(eager->tcp_connp);
1061 mutex_exit(&listener->tcp_eager_lock);
1062 mp = &eager->tcp_closemp;
1063 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp, tcp_eager_kill,
1064 eager->tcp_connp, NULL, SQ_FILL, SQTAG_TCP_EAGER_BLOWOFF);
1065 return (B_TRUE);
1066 }
1067
1068 /*
1069 * Reset any eager connection hanging off this listener
1070 * and then reclaim it's resources.
1071 */
1072 void
1073 tcp_eager_cleanup(tcp_t *listener, boolean_t q0_only)
1074 {
1075 tcp_t *eager;
1076 mblk_t *mp;
1077 tcp_stack_t *tcps = listener->tcp_tcps;
1078
1079 ASSERT(MUTEX_HELD(&listener->tcp_eager_lock));
1080
1081 if (!q0_only) {
1082 /* First cleanup q */
1083 TCP_STAT(tcps, tcp_eager_blowoff_q);
1084 eager = listener->tcp_eager_next_q;
1085 while (eager != NULL) {
1086 if (!eager->tcp_closemp_used) {
1087 eager->tcp_closemp_used = B_TRUE;
1088 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1089 CONN_INC_REF(eager->tcp_connp);
1090 mp = &eager->tcp_closemp;
1091 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
1092 tcp_eager_kill, eager->tcp_connp, NULL,
1093 SQ_FILL, SQTAG_TCP_EAGER_CLEANUP);
1094 }
1095 eager = eager->tcp_eager_next_q;
1096 }
1097 }
1098 /* Then cleanup q0 */
1099 TCP_STAT(tcps, tcp_eager_blowoff_q0);
1100 eager = listener->tcp_eager_next_q0;
1101 while (eager != listener) {
1102 if (!eager->tcp_closemp_used) {
1103 eager->tcp_closemp_used = B_TRUE;
1104 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1105 CONN_INC_REF(eager->tcp_connp);
1106 mp = &eager->tcp_closemp;
1107 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
1108 tcp_eager_kill, eager->tcp_connp, NULL, SQ_FILL,
1109 SQTAG_TCP_EAGER_CLEANUP_Q0);
1110 }
1111 eager = eager->tcp_eager_next_q0;
1112 }
1113 }
1114
1115 /*
1116 * If we are an eager connection hanging off a listener that hasn't
1117 * formally accepted the connection yet, get off his list and blow off
1118 * any data that we have accumulated.
1119 */
1120 void
1121 tcp_eager_unlink(tcp_t *tcp)
1122 {
1123 tcp_t *listener = tcp->tcp_listener;
1124
1125 ASSERT(listener != NULL);
1126 ASSERT(MUTEX_HELD(&listener->tcp_eager_lock));
1127 if (tcp->tcp_eager_next_q0 != NULL) {
1128 ASSERT(tcp->tcp_eager_prev_q0 != NULL);
1129
1130 /* Remove the eager tcp from q0 */
1131 tcp->tcp_eager_next_q0->tcp_eager_prev_q0 =
1132 tcp->tcp_eager_prev_q0;
1133 tcp->tcp_eager_prev_q0->tcp_eager_next_q0 =
1134 tcp->tcp_eager_next_q0;
1135 ASSERT(listener->tcp_conn_req_cnt_q0 > 0);
1136 listener->tcp_conn_req_cnt_q0--;
1137
1138 tcp->tcp_eager_next_q0 = NULL;
1139 tcp->tcp_eager_prev_q0 = NULL;
1140
1141 /*
1142 * Take the eager out, if it is in the list of droppable
1143 * eagers.
1144 */
1145 MAKE_UNDROPPABLE(tcp);
1146
1147 if (tcp->tcp_syn_rcvd_timeout != 0) {
1148 /* we have timed out before */
1149 ASSERT(listener->tcp_syn_rcvd_timeout > 0);
1150 listener->tcp_syn_rcvd_timeout--;
1151 }
1152 } else {
1153 tcp_t **tcpp = &listener->tcp_eager_next_q;
1154 tcp_t *prev = NULL;
1155
1156 for (; tcpp[0]; tcpp = &tcpp[0]->tcp_eager_next_q) {
1157 if (tcpp[0] == tcp) {
1158 if (listener->tcp_eager_last_q == tcp) {
1159 /*
1160 * If we are unlinking the last
1161 * element on the list, adjust
1162 * tail pointer. Set tail pointer
1163 * to nil when list is empty.
1164 */
1165 ASSERT(tcp->tcp_eager_next_q == NULL);
1166 if (listener->tcp_eager_last_q ==
1167 listener->tcp_eager_next_q) {
1168 listener->tcp_eager_last_q =
1169 NULL;
1170 } else {
1171 /*
1172 * We won't get here if there
1173 * is only one eager in the
1174 * list.
1175 */
1176 ASSERT(prev != NULL);
1177 listener->tcp_eager_last_q =
1178 prev;
1179 }
1180 }
1181 tcpp[0] = tcp->tcp_eager_next_q;
1182 tcp->tcp_eager_next_q = NULL;
1183 tcp->tcp_eager_last_q = NULL;
1184 ASSERT(listener->tcp_conn_req_cnt_q > 0);
1185 listener->tcp_conn_req_cnt_q--;
1186 break;
1187 }
1188 prev = tcpp[0];
1189 }
1190 }
1191 tcp->tcp_listener = NULL;
1192 }
1193
1194 /* BEGIN CSTYLED */
1195 /*
1196 *
1197 * The sockfs ACCEPT path:
1198 * =======================
1199 *
1200 * The eager is now established in its own perimeter as soon as SYN is
1201 * received in tcp_input_listener(). When sockfs receives conn_ind, it
1202 * completes the accept processing on the acceptor STREAM. The sending
1203 * of conn_ind part is common for both sockfs listener and a TLI/XTI
1204 * listener but a TLI/XTI listener completes the accept processing
1205 * on the listener perimeter.
1206 *
1207 * Common control flow for 3 way handshake:
1208 * ----------------------------------------
1209 *
1210 * incoming SYN (listener perimeter) -> tcp_input_listener()
1211 *
1212 * incoming SYN-ACK-ACK (eager perim) -> tcp_input_data()
1213 * send T_CONN_IND (listener perim) -> tcp_send_conn_ind()
1214 *
1215 * Sockfs ACCEPT Path:
1216 * -------------------
1217 *
1218 * open acceptor stream (tcp_open allocates tcp_tli_accept()
1219 * as STREAM entry point)
1220 *
1221 * soaccept() sends T_CONN_RES on the acceptor STREAM to tcp_tli_accept()
1222 *
1223 * tcp_tli_accept() extracts the eager and makes the q->q_ptr <-> eager
1224 * association (we are not behind eager's squeue but sockfs is protecting us
1225 * and no one knows about this stream yet. The STREAMS entry point q->q_info
1226 * is changed to point at tcp_wput().
1227 *
1228 * tcp_accept_common() sends any deferred eagers via tcp_send_pending() to
1229 * listener (done on listener's perimeter).
1230 *
1231 * tcp_tli_accept() calls tcp_accept_finish() on eagers perimeter to finish
1232 * accept.
1233 *
1234 * TLI/XTI client ACCEPT path:
1235 * ---------------------------
1236 *
1237 * soaccept() sends T_CONN_RES on the listener STREAM.
1238 *
1239 * tcp_tli_accept() -> tcp_accept_swap() complete the processing and send
1240 * a M_SETOPS mblk to eager perimeter to finish accept (tcp_accept_finish()).
1241 *
1242 * Locks:
1243 * ======
1244 *
1245 * listener->tcp_eager_lock protects the listeners->tcp_eager_next_q0 and
1246 * and listeners->tcp_eager_next_q.
1247 *
1248 * Referencing:
1249 * ============
1250 *
1251 * 1) We start out in tcp_input_listener by eager placing a ref on
1252 * listener and listener adding eager to listeners->tcp_eager_next_q0.
1253 *
1254 * 2) When a SYN-ACK-ACK arrives, we send the conn_ind to listener. Before
1255 * doing so we place a ref on the eager. This ref is finally dropped at the
1256 * end of tcp_accept_finish() while unwinding from the squeue, i.e. the
1257 * reference is dropped by the squeue framework.
1258 *
1259 * 3) The ref on listener placed in 1 above is dropped in tcp_accept_finish
1260 *
1261 * The reference must be released by the same entity that added the reference
1262 * In the above scheme, the eager is the entity that adds and releases the
1263 * references. Note that tcp_accept_finish executes in the squeue of the eager
1264 * (albeit after it is attached to the acceptor stream). Though 1. executes
1265 * in the listener's squeue, the eager is nascent at this point and the
1266 * reference can be considered to have been added on behalf of the eager.
1267 *
1268 * Eager getting a Reset or listener closing:
1269 * ==========================================
1270 *
1271 * Once the listener and eager are linked, the listener never does the unlink.
1272 * If the listener needs to close, tcp_eager_cleanup() is called which queues
1273 * a message on all eager perimeter. The eager then does the unlink, clears
1274 * any pointers to the listener's queue and drops the reference to the
1275 * listener. The listener waits in tcp_close outside the squeue until its
1276 * refcount has dropped to 1. This ensures that the listener has waited for
1277 * all eagers to clear their association with the listener.
1278 *
1279 * Similarly, if eager decides to go away, it can unlink itself and close.
1280 * When the T_CONN_RES comes down, we check if eager has closed. Note that
1281 * the reference to eager is still valid because of the extra ref we put
1282 * in tcp_send_conn_ind.
1283 *
1284 * Listener can always locate the eager under the protection
1285 * of the listener->tcp_eager_lock, and then do a refhold
1286 * on the eager during the accept processing.
1287 *
1288 * The acceptor stream accesses the eager in the accept processing
1289 * based on the ref placed on eager before sending T_conn_ind.
1290 * The only entity that can negate this refhold is a listener close
1291 * which is mutually exclusive with an active acceptor stream.
1292 *
1293 * Eager's reference on the listener
1294 * ===================================
1295 *
1296 * If the accept happens (even on a closed eager) the eager drops its
1297 * reference on the listener at the start of tcp_accept_finish. If the
1298 * eager is killed due to an incoming RST before the T_conn_ind is sent up,
1299 * the reference is dropped in tcp_closei_local. If the listener closes,
1300 * the reference is dropped in tcp_eager_kill. In all cases the reference
1301 * is dropped while executing in the eager's context (squeue).
1302 */
1303 /* END CSTYLED */
1304
1305 /* Process the SYN packet, mp, directed at the listener 'tcp' */
1306
1307 /*
1308 * THIS FUNCTION IS DIRECTLY CALLED BY IP VIA SQUEUE FOR SYN.
1309 * tcp_input_data will not see any packets for listeners since the listener
1310 * has conn_recv set to tcp_input_listener.
1311 */
1312 /* ARGSUSED */
1313 static void
1314 tcp_input_listener(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
1315 {
1316 tcpha_t *tcpha;
1317 uint32_t seg_seq;
1318 tcp_t *eager;
1319 int err;
1320 conn_t *econnp = NULL;
1321 squeue_t *new_sqp;
1322 mblk_t *mp1;
1323 uint_t ip_hdr_len;
1324 conn_t *lconnp = (conn_t *)arg;
1325 tcp_t *listener = lconnp->conn_tcp;
1326 tcp_stack_t *tcps = listener->tcp_tcps;
1327 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
1328 uint_t flags;
1329 mblk_t *tpi_mp;
1330 uint_t ifindex = ira->ira_ruifindex;
1331 boolean_t tlc_set = B_FALSE;
1332
1333 ip_hdr_len = ira->ira_ip_hdr_length;
1334 tcpha = (tcpha_t *)&mp->b_rptr[ip_hdr_len];
1335 flags = (unsigned int)tcpha->tha_flags & 0xFF;
1336
1337 DTRACE_TCP5(receive, mblk_t *, NULL, ip_xmit_attr_t *, lconnp->conn_ixa,
1338 __dtrace_tcp_void_ip_t *, mp->b_rptr, tcp_t *, listener,
1339 __dtrace_tcp_tcph_t *, tcpha);
1340
1341 if (!(flags & TH_SYN)) {
1342 if ((flags & TH_RST) || (flags & TH_URG)) {
1343 freemsg(mp);
1344 return;
1345 }
1346 if (flags & TH_ACK) {
1347 /* Note this executes in listener's squeue */
1348 tcp_xmit_listeners_reset(mp, ira, ipst, lconnp);
1349 return;
1350 }
1351
1352 freemsg(mp);
1353 return;
1354 }
1355
1356 if (listener->tcp_state != TCPS_LISTEN)
1357 goto error2;
1358
1359 ASSERT(IPCL_IS_BOUND(lconnp));
1360
1361 mutex_enter(&listener->tcp_eager_lock);
1362
1363 /*
1364 * The system is under memory pressure, so we need to do our part
1365 * to relieve the pressure. So we only accept new request if there
1366 * is nothing waiting to be accepted or waiting to complete the 3-way
1367 * handshake. This means that busy listener will not get too many
1368 * new requests which they cannot handle in time while non-busy
1369 * listener is still functioning properly.
1370 */
1371 if (tcps->tcps_reclaim && (listener->tcp_conn_req_cnt_q > 0 ||
1372 listener->tcp_conn_req_cnt_q0 > 0)) {
1373 mutex_exit(&listener->tcp_eager_lock);
1374 TCP_STAT(tcps, tcp_listen_mem_drop);
1375 goto error2;
1376 }
1377
1378 if (listener->tcp_conn_req_cnt_q >= listener->tcp_conn_req_max) {
1379 mutex_exit(&listener->tcp_eager_lock);
1380 TCP_STAT(tcps, tcp_listendrop);
1381 TCPS_BUMP_MIB(tcps, tcpListenDrop);
1382 if (lconnp->conn_debug) {
1383 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE|SL_ERROR,
1384 "tcp_input_listener: listen backlog (max=%d) "
1385 "overflow (%d pending) on %s",
1386 listener->tcp_conn_req_max,
1387 listener->tcp_conn_req_cnt_q,
1388 tcp_display(listener, NULL, DISP_PORT_ONLY));
1389 }
1390 goto error2;
1391 }
1392
1393 if (listener->tcp_conn_req_cnt_q0 >=
1394 listener->tcp_conn_req_max + tcps->tcps_conn_req_max_q0) {
1395 /*
1396 * Q0 is full. Drop a pending half-open req from the queue
1397 * to make room for the new SYN req. Also mark the time we
1398 * drop a SYN.
1399 *
1400 * A more aggressive defense against SYN attack will
1401 * be to set the "tcp_syn_defense" flag now.
1402 */
1403 TCP_STAT(tcps, tcp_listendropq0);
1404 listener->tcp_last_rcv_lbolt = ddi_get_lbolt64();
1405 if (!tcp_drop_q0(listener)) {
1406 mutex_exit(&listener->tcp_eager_lock);
1407 TCPS_BUMP_MIB(tcps, tcpListenDropQ0);
1408 if (lconnp->conn_debug) {
1409 (void) strlog(TCP_MOD_ID, 0, 3, SL_TRACE,
1410 "tcp_input_listener: listen half-open "
1411 "queue (max=%d) full (%d pending) on %s",
1412 tcps->tcps_conn_req_max_q0,
1413 listener->tcp_conn_req_cnt_q0,
1414 tcp_display(listener, NULL,
1415 DISP_PORT_ONLY));
1416 }
1417 goto error2;
1418 }
1419 }
1420
1421 /*
1422 * Enforce the limit set on the number of connections per listener.
1423 * Note that tlc_cnt starts with 1. So need to add 1 to tlc_max
1424 * for comparison.
1425 */
1426 if (listener->tcp_listen_cnt != NULL) {
1427 tcp_listen_cnt_t *tlc = listener->tcp_listen_cnt;
1428 int64_t now;
1429
1430 if (atomic_inc_32_nv(&tlc->tlc_cnt) > tlc->tlc_max + 1) {
1431 mutex_exit(&listener->tcp_eager_lock);
1432 now = ddi_get_lbolt64();
1433 atomic_dec_32(&tlc->tlc_cnt);
1434 TCP_STAT(tcps, tcp_listen_cnt_drop);
1435 tlc->tlc_drop++;
1436 if (now - tlc->tlc_report_time >
1437 MSEC_TO_TICK(TCP_TLC_REPORT_INTERVAL)) {
1438 zcmn_err(lconnp->conn_zoneid, CE_WARN,
1439 "Listener (port %d) connection max (%u) "
1440 "reached: %u attempts dropped total\n",
1441 ntohs(listener->tcp_connp->conn_lport),
1442 tlc->tlc_max, tlc->tlc_drop);
1443 tlc->tlc_report_time = now;
1444 }
1445 goto error2;
1446 }
1447 tlc_set = B_TRUE;
1448 }
1449
1450 mutex_exit(&listener->tcp_eager_lock);
1451
1452 /*
1453 * IP sets ira_sqp to either the senders conn_sqp (for loopback)
1454 * or based on the ring (for packets from GLD). Otherwise it is
1455 * set based on lbolt i.e., a somewhat random number.
1456 */
1457 ASSERT(ira->ira_sqp != NULL);
1458 new_sqp = ira->ira_sqp;
1459
1460 econnp = (conn_t *)tcp_get_conn(arg2, tcps);
1461 if (econnp == NULL)
1462 goto error2;
1463
1464 ASSERT(econnp->conn_netstack == lconnp->conn_netstack);
1465 econnp->conn_sqp = new_sqp;
1466 econnp->conn_initial_sqp = new_sqp;
1467 econnp->conn_ixa->ixa_sqp = new_sqp;
1468
1469 econnp->conn_fport = tcpha->tha_lport;
1470 econnp->conn_lport = tcpha->tha_fport;
1471
1472 err = conn_inherit_parent(lconnp, econnp);
1473 if (err != 0)
1474 goto error3;
1475
1476 /* We already know the laddr of the new connection is ours */
1477 econnp->conn_ixa->ixa_src_generation = ipst->ips_src_generation;
1478
1479 ASSERT(OK_32PTR(mp->b_rptr));
1480 ASSERT(IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION ||
1481 IPH_HDR_VERSION(mp->b_rptr) == IPV6_VERSION);
1482
1483 if (lconnp->conn_family == AF_INET) {
1484 ASSERT(IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION);
1485 tpi_mp = tcp_conn_create_v4(lconnp, econnp, mp, ira);
1486 } else {
1487 tpi_mp = tcp_conn_create_v6(lconnp, econnp, mp, ira);
1488 }
1489
1490 if (tpi_mp == NULL)
1491 goto error3;
1492
1493 eager = econnp->conn_tcp;
1494 eager->tcp_detached = B_TRUE;
1495 SOCK_CONNID_INIT(eager->tcp_connid);
1496
1497 /*
1498 * Initialize the eager's tcp_t and inherit some parameters from
1499 * the listener.
1500 */
1501 tcp_init_values(eager, listener);
1502
1503 ASSERT((econnp->conn_ixa->ixa_flags &
1504 (IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE |
1505 IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO)) ==
1506 (IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE |
1507 IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO));
1508
1509 if (!tcps->tcps_dev_flow_ctl)
1510 econnp->conn_ixa->ixa_flags |= IXAF_NO_DEV_FLOW_CTL;
1511
1512 /* Prepare for diffing against previous packets */
1513 eager->tcp_recvifindex = 0;
1514 eager->tcp_recvhops = 0xffffffffU;
1515
1516 if (!(ira->ira_flags & IRAF_IS_IPV4) && econnp->conn_bound_if == 0) {
1517 if (IN6_IS_ADDR_LINKSCOPE(&econnp->conn_faddr_v6) ||
1518 IN6_IS_ADDR_LINKSCOPE(&econnp->conn_laddr_v6)) {
1519 econnp->conn_incoming_ifindex = ifindex;
1520 econnp->conn_ixa->ixa_flags |= IXAF_SCOPEID_SET;
1521 econnp->conn_ixa->ixa_scopeid = ifindex;
1522 }
1523 }
1524
1525 if ((ira->ira_flags & (IRAF_IS_IPV4|IRAF_IPV4_OPTIONS)) ==
1526 (IRAF_IS_IPV4|IRAF_IPV4_OPTIONS) &&
1527 tcps->tcps_rev_src_routes) {
1528 ipha_t *ipha = (ipha_t *)mp->b_rptr;
1529 ip_pkt_t *ipp = &econnp->conn_xmit_ipp;
1530
1531 /* Source routing option copyover (reverse it) */
1532 err = ip_find_hdr_v4(ipha, ipp, B_TRUE);
1533 if (err != 0) {
1534 freemsg(tpi_mp);
1535 goto error3;
1536 }
1537 ip_pkt_source_route_reverse_v4(ipp);
1538 }
1539
1540 ASSERT(eager->tcp_conn.tcp_eager_conn_ind == NULL);
1541 ASSERT(!eager->tcp_tconnind_started);
1542 /*
1543 * If the SYN came with a credential, it's a loopback packet or a
1544 * labeled packet; attach the credential to the TPI message.
1545 */
1546 if (ira->ira_cred != NULL)
1547 mblk_setcred(tpi_mp, ira->ira_cred, ira->ira_cpid);
1548
1549 eager->tcp_conn.tcp_eager_conn_ind = tpi_mp;
1550 ASSERT(eager->tcp_ordrel_mp == NULL);
1551
1552 /* Inherit the listener's non-STREAMS flag */
1553 if (IPCL_IS_NONSTR(lconnp)) {
1554 econnp->conn_flags |= IPCL_NONSTR;
1555 /* All non-STREAMS tcp_ts are sockets */
1556 eager->tcp_issocket = B_TRUE;
1557 } else {
1558 /*
1559 * Pre-allocate the T_ordrel_ind mblk for TPI socket so that
1560 * at close time, we will always have that to send up.
1561 * Otherwise, we need to do special handling in case the
1562 * allocation fails at that time.
1563 */
1564 if ((eager->tcp_ordrel_mp = mi_tpi_ordrel_ind()) == NULL)
1565 goto error3;
1566 }
1567 /*
1568 * Now that the IP addresses and ports are setup in econnp we
1569 * can do the IPsec policy work.
1570 */
1571 if (ira->ira_flags & IRAF_IPSEC_SECURE) {
1572 if (lconnp->conn_policy != NULL) {
1573 /*
1574 * Inherit the policy from the listener; use
1575 * actions from ira
1576 */
1577 if (!ip_ipsec_policy_inherit(econnp, lconnp, ira)) {
1578 CONN_DEC_REF(econnp);
1579 freemsg(mp);
1580 goto error3;
1581 }
1582 }
1583 }
1584
1585 /*
1586 * tcp_set_destination() may set tcp_rwnd according to the route
1587 * metrics. If it does not, the eager's receive window will be set
1588 * to the listener's receive window later in this function.
1589 */
1590 eager->tcp_rwnd = 0;
1591
1592 if (is_system_labeled()) {
1593 ip_xmit_attr_t *ixa = econnp->conn_ixa;
1594
1595 ASSERT(ira->ira_tsl != NULL);
1596 /* Discard any old label */
1597 if (ixa->ixa_free_flags & IXA_FREE_TSL) {
1598 ASSERT(ixa->ixa_tsl != NULL);
1599 label_rele(ixa->ixa_tsl);
1600 ixa->ixa_free_flags &= ~IXA_FREE_TSL;
1601 ixa->ixa_tsl = NULL;
1602 }
1603 if ((lconnp->conn_mlp_type != mlptSingle ||
1604 lconnp->conn_mac_mode != CONN_MAC_DEFAULT) &&
1605 ira->ira_tsl != NULL) {
1606 /*
1607 * If this is an MLP connection or a MAC-Exempt
1608 * connection with an unlabeled node, packets are to be
1609 * exchanged using the security label of the received
1610 * SYN packet instead of the server application's label.
1611 * tsol_check_dest called from ip_set_destination
1612 * might later update TSF_UNLABELED by replacing
1613 * ixa_tsl with a new label.
1614 */
1615 label_hold(ira->ira_tsl);
1616 ip_xmit_attr_replace_tsl(ixa, ira->ira_tsl);
1617 DTRACE_PROBE2(mlp_syn_accept, conn_t *,
1618 econnp, ts_label_t *, ixa->ixa_tsl)
1619 } else {
1620 ixa->ixa_tsl = crgetlabel(econnp->conn_cred);
1621 DTRACE_PROBE2(syn_accept, conn_t *,
1622 econnp, ts_label_t *, ixa->ixa_tsl)
1623 }
1624 /*
1625 * conn_connect() called from tcp_set_destination will verify
1626 * the destination is allowed to receive packets at the
1627 * security label of the SYN-ACK we are generating. As part of
1628 * that, tsol_check_dest() may create a new effective label for
1629 * this connection.
1630 * Finally conn_connect() will call conn_update_label.
1631 * All that remains for TCP to do is to call
1632 * conn_build_hdr_template which is done as part of
1633 * tcp_set_destination.
1634 */
1635 }
1636
1637 /*
1638 * Since we will clear tcp_listener before we clear tcp_detached
1639 * in the accept code we need tcp_hard_binding aka tcp_accept_inprogress
1640 * so we can tell a TCP_IS_DETACHED_NONEAGER apart.
1641 */
1642 eager->tcp_hard_binding = B_TRUE;
1643
1644 tcp_bind_hash_insert(&tcps->tcps_bind_fanout[
1645 TCP_BIND_HASH(econnp->conn_lport)], eager, 0);
1646
1647 CL_INET_CONNECT(econnp, B_FALSE, err);
1648 if (err != 0) {
1649 tcp_bind_hash_remove(eager);
1650 goto error3;
1651 }
1652
1653 SOCK_CONNID_BUMP(eager->tcp_connid);
1654
1655 /*
1656 * Adapt our mss, ttl, ... based on the remote address.
1657 */
1658
1659 if (tcp_set_destination(eager) != 0) {
1660 TCPS_BUMP_MIB(tcps, tcpAttemptFails);
1661 /* Undo the bind_hash_insert */
1662 tcp_bind_hash_remove(eager);
1663 goto error3;
1664 }
1665
1666 /* Process all TCP options. */
1667 tcp_process_options(eager, tcpha);
1668
1669 /* Is the other end ECN capable? */
1670 if (tcps->tcps_ecn_permitted >= 1 &&
1671 (tcpha->tha_flags & (TH_ECE|TH_CWR)) == (TH_ECE|TH_CWR)) {
1672 eager->tcp_ecn_ok = B_TRUE;
1673 }
1674
1675 /*
1676 * The listener's conn_rcvbuf should be the default window size or a
1677 * window size changed via SO_RCVBUF option. First round up the
1678 * eager's tcp_rwnd to the nearest MSS. Then find out the window
1679 * scale option value if needed. Call tcp_rwnd_set() to finish the
1680 * setting.
1681 *
1682 * Note if there is a rpipe metric associated with the remote host,
1683 * we should not inherit receive window size from listener.
1684 */
1685 eager->tcp_rwnd = MSS_ROUNDUP(
1686 (eager->tcp_rwnd == 0 ? econnp->conn_rcvbuf :
1687 eager->tcp_rwnd), eager->tcp_mss);
1688 if (eager->tcp_snd_ws_ok)
1689 tcp_set_ws_value(eager);
1690 /*
1691 * Note that this is the only place tcp_rwnd_set() is called for
1692 * accepting a connection. We need to call it here instead of
1693 * after the 3-way handshake because we need to tell the other
1694 * side our rwnd in the SYN-ACK segment.
1695 */
1696 (void) tcp_rwnd_set(eager, eager->tcp_rwnd);
1697
1698 ASSERT(eager->tcp_connp->conn_rcvbuf != 0 &&
1699 eager->tcp_connp->conn_rcvbuf == eager->tcp_rwnd);
1700
1701 ASSERT(econnp->conn_rcvbuf != 0 &&
1702 econnp->conn_rcvbuf == eager->tcp_rwnd);
1703
1704 /* Put a ref on the listener for the eager. */
1705 CONN_INC_REF(lconnp);
1706 mutex_enter(&listener->tcp_eager_lock);
1707 listener->tcp_eager_next_q0->tcp_eager_prev_q0 = eager;
1708 eager->tcp_eager_next_q0 = listener->tcp_eager_next_q0;
1709 listener->tcp_eager_next_q0 = eager;
1710 eager->tcp_eager_prev_q0 = listener;
1711
1712 /* Set tcp_listener before adding it to tcp_conn_fanout */
1713 eager->tcp_listener = listener;
1714 eager->tcp_saved_listener = listener;
1715
1716 /*
1717 * Set tcp_listen_cnt so that when the connection is done, the counter
1718 * is decremented.
1719 */
1720 eager->tcp_listen_cnt = listener->tcp_listen_cnt;
1721
1722 /*
1723 * Tag this detached tcp vector for later retrieval
1724 * by our listener client in tcp_accept().
1725 */
1726 eager->tcp_conn_req_seqnum = listener->tcp_conn_req_seqnum;
1727 listener->tcp_conn_req_cnt_q0++;
1728 if (++listener->tcp_conn_req_seqnum == -1) {
1729 /*
1730 * -1 is "special" and defined in TPI as something
1731 * that should never be used in T_CONN_IND
1732 */
1733 ++listener->tcp_conn_req_seqnum;
1734 }
1735 mutex_exit(&listener->tcp_eager_lock);
1736
1737 if (listener->tcp_syn_defense) {
1738 /* Don't drop the SYN that comes from a good IP source */
1739 ipaddr_t *addr_cache;
1740
1741 addr_cache = (ipaddr_t *)(listener->tcp_ip_addr_cache);
1742 if (addr_cache != NULL && econnp->conn_faddr_v4 ==
1743 addr_cache[IP_ADDR_CACHE_HASH(econnp->conn_faddr_v4)]) {
1744 eager->tcp_dontdrop = B_TRUE;
1745 }
1746 }
1747
1748 /*
1749 * We need to insert the eager in its own perimeter but as soon
1750 * as we do that, we expose the eager to the classifier and
1751 * should not touch any field outside the eager's perimeter.
1752 * So do all the work necessary before inserting the eager
1753 * in its own perimeter. Be optimistic that conn_connect()
1754 * will succeed but undo everything if it fails.
1755 */
1756 seg_seq = ntohl(tcpha->tha_seq);
1757 eager->tcp_irs = seg_seq;
1758 eager->tcp_rack = seg_seq;
1759 eager->tcp_rnxt = seg_seq + 1;
1760 eager->tcp_tcpha->tha_ack = htonl(eager->tcp_rnxt);
1761 TCPS_BUMP_MIB(tcps, tcpPassiveOpens);
1762 eager->tcp_state = TCPS_SYN_RCVD;
1763 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
1764 econnp->conn_ixa, void, NULL, tcp_t *, eager, void, NULL,
1765 int32_t, TCPS_LISTEN);
1766
1767 mp1 = tcp_xmit_mp(eager, eager->tcp_xmit_head, eager->tcp_mss,
1768 NULL, NULL, eager->tcp_iss, B_FALSE, NULL, B_FALSE);
1769 if (mp1 == NULL) {
1770 /*
1771 * Increment the ref count as we are going to
1772 * enqueueing an mp in squeue
1773 */
1774 CONN_INC_REF(econnp);
1775 goto error;
1776 }
1777
1778 /*
1779 * We need to start the rto timer. In normal case, we start
1780 * the timer after sending the packet on the wire (or at
1781 * least believing that packet was sent by waiting for
1782 * conn_ip_output() to return). Since this is the first packet
1783 * being sent on the wire for the eager, our initial tcp_rto
1784 * is at least tcp_rexmit_interval_min which is a fairly
1785 * large value to allow the algorithm to adjust slowly to large
1786 * fluctuations of RTT during first few transmissions.
1787 *
1788 * Starting the timer first and then sending the packet in this
1789 * case shouldn't make much difference since tcp_rexmit_interval_min
1790 * is of the order of several 100ms and starting the timer
1791 * first and then sending the packet will result in difference
1792 * of few micro seconds.
1793 *
1794 * Without this optimization, we are forced to hold the fanout
1795 * lock across the ipcl_bind_insert() and sending the packet
1796 * so that we don't race against an incoming packet (maybe RST)
1797 * for this eager.
1798 *
1799 * It is necessary to acquire an extra reference on the eager
1800 * at this point and hold it until after tcp_send_data() to
1801 * ensure against an eager close race.
1802 */
1803
1804 CONN_INC_REF(econnp);
1805
1806 TCP_TIMER_RESTART(eager, eager->tcp_rto);
1807
1808 /*
1809 * Insert the eager in its own perimeter now. We are ready to deal
1810 * with any packets on eager.
1811 */
1812 if (ipcl_conn_insert(econnp) != 0)
1813 goto error;
1814
1815 ASSERT(econnp->conn_ixa->ixa_notify_cookie == econnp->conn_tcp);
1816 freemsg(mp);
1817 /*
1818 * Send the SYN-ACK. Use the right squeue so that conn_ixa is
1819 * only used by one thread at a time.
1820 */
1821 if (econnp->conn_sqp == lconnp->conn_sqp) {
1822 DTRACE_TCP5(send, mblk_t *, NULL, ip_xmit_attr_t *,
1823 econnp->conn_ixa, __dtrace_tcp_void_ip_t *, mp1->b_rptr,
1824 tcp_t *, eager, __dtrace_tcp_tcph_t *,
1825 &mp1->b_rptr[econnp->conn_ixa->ixa_ip_hdr_length]);
1826 (void) conn_ip_output(mp1, econnp->conn_ixa);
1827 CONN_DEC_REF(econnp);
1828 } else {
1829 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp1, tcp_send_synack,
1830 econnp, NULL, SQ_PROCESS, SQTAG_TCP_SEND_SYNACK);
1831 }
1832 return;
1833 error:
1834 freemsg(mp1);
1835 eager->tcp_closemp_used = B_TRUE;
1836 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1837 mp1 = &eager->tcp_closemp;
1838 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp1, tcp_eager_kill,
1839 econnp, NULL, SQ_FILL, SQTAG_TCP_CONN_REQ_2);
1840
1841 /*
1842 * If a connection already exists, send the mp to that connections so
1843 * that it can be appropriately dealt with.
1844 */
1845 ipst = tcps->tcps_netstack->netstack_ip;
1846
1847 if ((econnp = ipcl_classify(mp, ira, ipst)) != NULL) {
1848 if (!IPCL_IS_CONNECTED(econnp)) {
1849 /*
1850 * Something bad happened. ipcl_conn_insert()
1851 * failed because a connection already existed
1852 * in connected hash but we can't find it
1853 * anymore (someone blew it away). Just
1854 * free this message and hopefully remote
1855 * will retransmit at which time the SYN can be
1856 * treated as a new connection or dealth with
1857 * a TH_RST if a connection already exists.
1858 */
1859 CONN_DEC_REF(econnp);
1860 freemsg(mp);
1861 } else {
1862 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp, tcp_input_data,
1863 econnp, ira, SQ_FILL, SQTAG_TCP_CONN_REQ_1);
1864 }
1865 } else {
1866 /* Nobody wants this packet */
1867 freemsg(mp);
1868 }
1869 return;
1870 error3:
1871 CONN_DEC_REF(econnp);
1872 error2:
1873 freemsg(mp);
1874 if (tlc_set)
1875 atomic_dec_32(&listener->tcp_listen_cnt->tlc_cnt);
1876 }
1877
1878 /*
1879 * In an ideal case of vertical partition in NUMA architecture, its
1880 * beneficial to have the listener and all the incoming connections
1881 * tied to the same squeue. The other constraint is that incoming
1882 * connections should be tied to the squeue attached to interrupted
1883 * CPU for obvious locality reason so this leaves the listener to
1884 * be tied to the same squeue. Our only problem is that when listener
1885 * is binding, the CPU that will get interrupted by the NIC whose
1886 * IP address the listener is binding to is not even known. So
1887 * the code below allows us to change that binding at the time the
1888 * CPU is interrupted by virtue of incoming connection's squeue.
1889 *
1890 * This is usefull only in case of a listener bound to a specific IP
1891 * address. For other kind of listeners, they get bound the
1892 * very first time and there is no attempt to rebind them.
1893 */
1894 void
1895 tcp_input_listener_unbound(void *arg, mblk_t *mp, void *arg2,
1896 ip_recv_attr_t *ira)
1897 {
1898 conn_t *connp = (conn_t *)arg;
1899 squeue_t *sqp = (squeue_t *)arg2;
1900 squeue_t *new_sqp;
1901 uint32_t conn_flags;
1902
1903 /*
1904 * IP sets ira_sqp to either the senders conn_sqp (for loopback)
1905 * or based on the ring (for packets from GLD). Otherwise it is
1906 * set based on lbolt i.e., a somewhat random number.
1907 */
1908 ASSERT(ira->ira_sqp != NULL);
1909 new_sqp = ira->ira_sqp;
1910
1911 if (connp->conn_fanout == NULL)
1912 goto done;
1913
1914 if (!(connp->conn_flags & IPCL_FULLY_BOUND)) {
1915 mutex_enter(&connp->conn_fanout->connf_lock);
1916 mutex_enter(&connp->conn_lock);
1917 /*
1918 * No one from read or write side can access us now
1919 * except for already queued packets on this squeue.
1920 * But since we haven't changed the squeue yet, they
1921 * can't execute. If they are processed after we have
1922 * changed the squeue, they are sent back to the
1923 * correct squeue down below.
1924 * But a listner close can race with processing of
1925 * incoming SYN. If incoming SYN processing changes
1926 * the squeue then the listener close which is waiting
1927 * to enter the squeue would operate on the wrong
1928 * squeue. Hence we don't change the squeue here unless
1929 * the refcount is exactly the minimum refcount. The
1930 * minimum refcount of 4 is counted as - 1 each for
1931 * TCP and IP, 1 for being in the classifier hash, and
1932 * 1 for the mblk being processed.
1933 */
1934
1935 if (connp->conn_ref != 4 ||
1936 connp->conn_tcp->tcp_state != TCPS_LISTEN) {
1937 mutex_exit(&connp->conn_lock);
1938 mutex_exit(&connp->conn_fanout->connf_lock);
1939 goto done;
1940 }
1941 if (connp->conn_sqp != new_sqp) {
1942 while (connp->conn_sqp != new_sqp)
1943 (void) atomic_cas_ptr(&connp->conn_sqp, sqp,
1944 new_sqp);
1945 /* No special MT issues for outbound ixa_sqp hint */
1946 connp->conn_ixa->ixa_sqp = new_sqp;
1947 }
1948
1949 do {
1950 conn_flags = connp->conn_flags;
1951 conn_flags |= IPCL_FULLY_BOUND;
1952 (void) atomic_cas_32(&connp->conn_flags,
1953 connp->conn_flags, conn_flags);
1954 } while (!(connp->conn_flags & IPCL_FULLY_BOUND));
1955
1956 mutex_exit(&connp->conn_fanout->connf_lock);
1957 mutex_exit(&connp->conn_lock);
1958
1959 /*
1960 * Assume we have picked a good squeue for the listener. Make
1961 * subsequent SYNs not try to change the squeue.
1962 */
1963 connp->conn_recv = tcp_input_listener;
1964 }
1965
1966 done:
1967 if (connp->conn_sqp != sqp) {
1968 CONN_INC_REF(connp);
1969 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, connp->conn_recv, connp,
1970 ira, SQ_FILL, SQTAG_TCP_CONN_REQ_UNBOUND);
1971 } else {
1972 tcp_input_listener(connp, mp, sqp, ira);
1973 }
1974 }
1975
1976 /*
1977 * Send up all messages queued on tcp_rcv_list.
1978 */
1979 uint_t
1980 tcp_rcv_drain(tcp_t *tcp)
1981 {
1982 mblk_t *mp;
1983 uint_t ret = 0;
1984 #ifdef DEBUG
1985 uint_t cnt = 0;
1986 #endif
1987 queue_t *q = tcp->tcp_connp->conn_rq;
1988
1989 /* Can't drain on an eager connection */
1990 if (tcp->tcp_listener != NULL)
1991 return (ret);
1992
1993 /* Can't be a non-STREAMS connection */
1994 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
1995
1996 /* No need for the push timer now. */
1997 if (tcp->tcp_push_tid != 0) {
1998 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
1999 tcp->tcp_push_tid = 0;
2000 }
2001
2002 /*
2003 * Handle two cases here: we are currently fused or we were
2004 * previously fused and have some urgent data to be delivered
2005 * upstream. The latter happens because we either ran out of
2006 * memory or were detached and therefore sending the SIGURG was
2007 * deferred until this point. In either case we pass control
2008 * over to tcp_fuse_rcv_drain() since it may need to complete
2009 * some work.
2010 */
2011 if ((tcp->tcp_fused || tcp->tcp_fused_sigurg)) {
2012 if (tcp_fuse_rcv_drain(q, tcp, tcp->tcp_fused ? NULL :
2013 &tcp->tcp_fused_sigurg_mp))
2014 return (ret);
2015 }
2016
2017 while ((mp = tcp->tcp_rcv_list) != NULL) {
2018 tcp->tcp_rcv_list = mp->b_next;
2019 mp->b_next = NULL;
2020 #ifdef DEBUG
2021 cnt += msgdsize(mp);
2022 #endif
2023 putnext(q, mp);
2024 }
2025 #ifdef DEBUG
2026 ASSERT(cnt == tcp->tcp_rcv_cnt);
2027 #endif
2028 tcp->tcp_rcv_last_head = NULL;
2029 tcp->tcp_rcv_last_tail = NULL;
2030 tcp->tcp_rcv_cnt = 0;
2031
2032 if (canputnext(q))
2033 return (tcp_rwnd_reopen(tcp));
2034
2035 return (ret);
2036 }
2037
2038 /*
2039 * Queue data on tcp_rcv_list which is a b_next chain.
2040 * tcp_rcv_last_head/tail is the last element of this chain.
2041 * Each element of the chain is a b_cont chain.
2042 *
2043 * M_DATA messages are added to the current element.
2044 * Other messages are added as new (b_next) elements.
2045 */
2046 void
2047 tcp_rcv_enqueue(tcp_t *tcp, mblk_t *mp, uint_t seg_len, cred_t *cr)
2048 {
2049 ASSERT(seg_len == msgdsize(mp));
2050 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_rcv_last_head != NULL);
2051
2052 if (is_system_labeled()) {
2053 ASSERT(cr != NULL || msg_getcred(mp, NULL) != NULL);
2054 /*
2055 * Provide for protocols above TCP such as RPC. NOPID leaves
2056 * db_cpid unchanged.
2057 * The cred could have already been set.
2058 */
2059 if (cr != NULL)
2060 mblk_setcred(mp, cr, NOPID);
2061 }
2062
2063 if (tcp->tcp_rcv_list == NULL) {
2064 ASSERT(tcp->tcp_rcv_last_head == NULL);
2065 tcp->tcp_rcv_list = mp;
2066 tcp->tcp_rcv_last_head = mp;
2067 } else if (DB_TYPE(mp) == DB_TYPE(tcp->tcp_rcv_last_head)) {
2068 tcp->tcp_rcv_last_tail->b_cont = mp;
2069 } else {
2070 tcp->tcp_rcv_last_head->b_next = mp;
2071 tcp->tcp_rcv_last_head = mp;
2072 }
2073
2074 while (mp->b_cont)
2075 mp = mp->b_cont;
2076
2077 tcp->tcp_rcv_last_tail = mp;
2078 tcp->tcp_rcv_cnt += seg_len;
2079 tcp->tcp_rwnd -= seg_len;
2080 }
2081
2082 /* Generate an ACK-only (no data) segment for a TCP endpoint */
2083 mblk_t *
2084 tcp_ack_mp(tcp_t *tcp)
2085 {
2086 uint32_t seq_no;
2087 tcp_stack_t *tcps = tcp->tcp_tcps;
2088 conn_t *connp = tcp->tcp_connp;
2089
2090 /*
2091 * There are a few cases to be considered while setting the sequence no.
2092 * Essentially, we can come here while processing an unacceptable pkt
2093 * in the TCPS_SYN_RCVD state, in which case we set the sequence number
2094 * to snxt (per RFC 793), note the swnd wouldn't have been set yet.
2095 * If we are here for a zero window probe, stick with suna. In all
2096 * other cases, we check if suna + swnd encompasses snxt and set
2097 * the sequence number to snxt, if so. If snxt falls outside the
2098 * window (the receiver probably shrunk its window), we will go with
2099 * suna + swnd, otherwise the sequence no will be unacceptable to the
2100 * receiver.
2101 */
2102 if (tcp->tcp_zero_win_probe) {
2103 seq_no = tcp->tcp_suna;
2104 } else if (tcp->tcp_state == TCPS_SYN_RCVD) {
2105 ASSERT(tcp->tcp_swnd == 0);
2106 seq_no = tcp->tcp_snxt;
2107 } else {
2108 seq_no = SEQ_GT(tcp->tcp_snxt,
2109 (tcp->tcp_suna + tcp->tcp_swnd)) ?
2110 (tcp->tcp_suna + tcp->tcp_swnd) : tcp->tcp_snxt;
2111 }
2112
2113 if (tcp->tcp_valid_bits) {
2114 /*
2115 * For the complex case where we have to send some
2116 * controls (FIN or SYN), let tcp_xmit_mp do it.
2117 */
2118 return (tcp_xmit_mp(tcp, NULL, 0, NULL, NULL, seq_no, B_FALSE,
2119 NULL, B_FALSE));
2120 } else {
2121 /* Generate a simple ACK */
2122 int data_length;
2123 uchar_t *rptr;
2124 tcpha_t *tcpha;
2125 mblk_t *mp1;
2126 int32_t total_hdr_len;
2127 int32_t tcp_hdr_len;
2128 int32_t num_sack_blk = 0;
2129 int32_t sack_opt_len;
2130 ip_xmit_attr_t *ixa = connp->conn_ixa;
2131
2132 /*
2133 * Allocate space for TCP + IP headers
2134 * and link-level header
2135 */
2136 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
2137 num_sack_blk = MIN(tcp->tcp_max_sack_blk,
2138 tcp->tcp_num_sack_blk);
2139 sack_opt_len = num_sack_blk * sizeof (sack_blk_t) +
2140 TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN;
2141 total_hdr_len = connp->conn_ht_iphc_len + sack_opt_len;
2142 tcp_hdr_len = connp->conn_ht_ulp_len + sack_opt_len;
2143 } else {
2144 total_hdr_len = connp->conn_ht_iphc_len;
2145 tcp_hdr_len = connp->conn_ht_ulp_len;
2146 }
2147 mp1 = allocb(total_hdr_len + tcps->tcps_wroff_xtra, BPRI_MED);
2148 if (!mp1)
2149 return (NULL);
2150
2151 /* Update the latest receive window size in TCP header. */
2152 tcp->tcp_tcpha->tha_win =
2153 htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
2154 /* copy in prototype TCP + IP header */
2155 rptr = mp1->b_rptr + tcps->tcps_wroff_xtra;
2156 mp1->b_rptr = rptr;
2157 mp1->b_wptr = rptr + total_hdr_len;
2158 bcopy(connp->conn_ht_iphc, rptr, connp->conn_ht_iphc_len);
2159
2160 tcpha = (tcpha_t *)&rptr[ixa->ixa_ip_hdr_length];
2161
2162 /* Set the TCP sequence number. */
2163 tcpha->tha_seq = htonl(seq_no);
2164
2165 /* Set up the TCP flag field. */
2166 tcpha->tha_flags = (uchar_t)TH_ACK;
2167 if (tcp->tcp_ecn_echo_on)
2168 tcpha->tha_flags |= TH_ECE;
2169
2170 tcp->tcp_rack = tcp->tcp_rnxt;
2171 tcp->tcp_rack_cnt = 0;
2172
2173 /* fill in timestamp option if in use */
2174 if (tcp->tcp_snd_ts_ok) {
2175 uint32_t llbolt = (uint32_t)LBOLT_FASTPATH;
2176
2177 U32_TO_BE32(llbolt,
2178 (char *)tcpha + TCP_MIN_HEADER_LENGTH+4);
2179 U32_TO_BE32(tcp->tcp_ts_recent,
2180 (char *)tcpha + TCP_MIN_HEADER_LENGTH+8);
2181 }
2182
2183 /* Fill in SACK options */
2184 if (num_sack_blk > 0) {
2185 uchar_t *wptr = (uchar_t *)tcpha +
2186 connp->conn_ht_ulp_len;
2187 sack_blk_t *tmp;
2188 int32_t i;
2189
2190 wptr[0] = TCPOPT_NOP;
2191 wptr[1] = TCPOPT_NOP;
2192 wptr[2] = TCPOPT_SACK;
2193 wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk *
2194 sizeof (sack_blk_t);
2195 wptr += TCPOPT_REAL_SACK_LEN;
2196
2197 tmp = tcp->tcp_sack_list;
2198 for (i = 0; i < num_sack_blk; i++) {
2199 U32_TO_BE32(tmp[i].begin, wptr);
2200 wptr += sizeof (tcp_seq);
2201 U32_TO_BE32(tmp[i].end, wptr);
2202 wptr += sizeof (tcp_seq);
2203 }
2204 tcpha->tha_offset_and_reserved +=
2205 ((num_sack_blk * 2 + 1) << 4);
2206 }
2207
2208 ixa->ixa_pktlen = total_hdr_len;
2209
2210 if (ixa->ixa_flags & IXAF_IS_IPV4) {
2211 ((ipha_t *)rptr)->ipha_length = htons(total_hdr_len);
2212 } else {
2213 ip6_t *ip6 = (ip6_t *)rptr;
2214
2215 ip6->ip6_plen = htons(total_hdr_len - IPV6_HDR_LEN);
2216 }
2217
2218 /*
2219 * Prime pump for checksum calculation in IP. Include the
2220 * adjustment for a source route if any.
2221 */
2222 data_length = tcp_hdr_len + connp->conn_sum;
2223 data_length = (data_length >> 16) + (data_length & 0xFFFF);
2224 tcpha->tha_sum = htons(data_length);
2225
2226 if (tcp->tcp_ip_forward_progress) {
2227 tcp->tcp_ip_forward_progress = B_FALSE;
2228 connp->conn_ixa->ixa_flags |= IXAF_REACH_CONF;
2229 } else {
2230 connp->conn_ixa->ixa_flags &= ~IXAF_REACH_CONF;
2231 }
2232 return (mp1);
2233 }
2234 }
2235
2236 /*
2237 * Dummy socket upcalls for if/when the conn_t gets detached from a
2238 * direct-callback sonode via a user-driven close(). Easy to catch with
2239 * DTrace FBT, and should be mostly harmless.
2240 */
2241
2242 /* ARGSUSED */
2243 static sock_upper_handle_t
2244 tcp_dummy_newconn(sock_upper_handle_t x, sock_lower_handle_t y,
2245 sock_downcalls_t *z, cred_t *cr, pid_t pid, sock_upcalls_t **ignored)
2246 {
2247 ASSERT(0); /* Panic in debug, otherwise ignore. */
2248 return (NULL);
2249 }
2250
2251 /* ARGSUSED */
2252 static void
2253 tcp_dummy_connected(sock_upper_handle_t x, sock_connid_t y, cred_t *cr,
2254 pid_t pid)
2255 {
2256 ASSERT(x == NULL);
2257 /* Normally we'd crhold(cr) and attach it to socket state. */
2258 /* LINTED */
2259 }
2260
2261 /* ARGSUSED */
2262 static int
2263 tcp_dummy_disconnected(sock_upper_handle_t x, sock_connid_t y, int blah)
2264 {
2265 ASSERT(0); /* Panic in debug, otherwise ignore. */
2266 return (-1);
2267 }
2268
2269 /* ARGSUSED */
2270 static void
2271 tcp_dummy_opctl(sock_upper_handle_t x, sock_opctl_action_t y, uintptr_t blah)
2272 {
2273 ASSERT(x == NULL);
2274 /* We really want this one to be a harmless NOP for now. */
2275 /* LINTED */
2276 }
2277
2278 /* ARGSUSED */
2279 static ssize_t
2280 tcp_dummy_recv(sock_upper_handle_t x, mblk_t *mp, size_t len, int flags,
2281 int *error, boolean_t *push)
2282 {
2283 ASSERT(x == NULL);
2284
2285 /*
2286 * Consume the message, set ESHUTDOWN, and return an error.
2287 * Nobody's home!
2288 */
2289 freemsg(mp);
2290 *error = ESHUTDOWN;
2291 return (-1);
2292 }
2293
2294 /* ARGSUSED */
2295 static void
2296 tcp_dummy_set_proto_props(sock_upper_handle_t x, struct sock_proto_props *y)
2297 {
2298 ASSERT(0); /* Panic in debug, otherwise ignore. */
2299 }
2300
2301 /* ARGSUSED */
2302 static void
2303 tcp_dummy_txq_full(sock_upper_handle_t x, boolean_t y)
2304 {
2305 ASSERT(0); /* Panic in debug, otherwise ignore. */
2306 }
2307
2308 /* ARGSUSED */
2309 static void
2310 tcp_dummy_signal_oob(sock_upper_handle_t x, ssize_t len)
2311 {
2312 ASSERT(x == NULL);
2313 /* Otherwise, this would signal socket state about OOB data. */
2314 }
2315
2316 /* ARGSUSED */
2317 static void
2318 tcp_dummy_set_error(sock_upper_handle_t x, int err)
2319 {
2320 ASSERT(0); /* Panic in debug, otherwise ignore. */
2321 }
2322
2323 /* ARGSUSED */
2324 static void
2325 tcp_dummy_onearg(sock_upper_handle_t x)
2326 {
2327 ASSERT(0); /* Panic in debug, otherwise ignore. */
2328 }
2329
2330 static sock_upcalls_t tcp_dummy_upcalls = {
2331 tcp_dummy_newconn,
2332 tcp_dummy_connected,
2333 tcp_dummy_disconnected,
2334 tcp_dummy_opctl,
2335 tcp_dummy_recv,
2336 tcp_dummy_set_proto_props,
2337 tcp_dummy_txq_full,
2338 tcp_dummy_signal_oob,
2339 tcp_dummy_onearg,
2340 tcp_dummy_set_error,
2341 tcp_dummy_onearg
2342 };
2343
2344 /*
2345 * Handle M_DATA messages from IP. Its called directly from IP via
2346 * squeue for received IP packets.
2347 *
2348 * The first argument is always the connp/tcp to which the mp belongs.
2349 * There are no exceptions to this rule. The caller has already put
2350 * a reference on this connp/tcp and once tcp_input_data() returns,
2351 * the squeue will do the refrele.
2352 *
2353 * The TH_SYN for the listener directly go to tcp_input_listener via
2354 * squeue. ICMP errors go directly to tcp_icmp_input().
2355 *
2356 * sqp: NULL = recursive, sqp != NULL means called from squeue
2357 */
2358 void
2359 tcp_input_data(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
2360 {
2361 int32_t bytes_acked;
2362 int32_t gap;
2363 mblk_t *mp1;
2364 uint_t flags;
2365 uint32_t new_swnd = 0;
2366 uchar_t *iphdr;
2367 uchar_t *rptr;
2368 int32_t rgap;
2369 uint32_t seg_ack;
2370 int seg_len;
2371 uint_t ip_hdr_len;
2372 uint32_t seg_seq;
2373 tcpha_t *tcpha;
2374 int urp;
2375 tcp_opt_t tcpopt;
2376 ip_pkt_t ipp;
2377 boolean_t ofo_seg = B_FALSE; /* Out of order segment */
2378 uint32_t cwnd;
2379 uint32_t add;
2380 int npkt;
2381 int mss;
2382 conn_t *connp = (conn_t *)arg;
2383 squeue_t *sqp = (squeue_t *)arg2;
2384 tcp_t *tcp = connp->conn_tcp;
2385 tcp_stack_t *tcps = tcp->tcp_tcps;
2386 sock_upcalls_t *sockupcalls;
2387
2388 /*
2389 * RST from fused tcp loopback peer should trigger an unfuse.
2390 */
2391 if (tcp->tcp_fused) {
2392 TCP_STAT(tcps, tcp_fusion_aborted);
2393 tcp_unfuse(tcp);
2394 }
2395
2396 iphdr = mp->b_rptr;
2397 rptr = mp->b_rptr;
2398 ASSERT(OK_32PTR(rptr));
2399
2400 ip_hdr_len = ira->ira_ip_hdr_length;
2401 if (connp->conn_recv_ancillary.crb_all != 0) {
2402 /*
2403 * Record packet information in the ip_pkt_t
2404 */
2405 ipp.ipp_fields = 0;
2406 if (ira->ira_flags & IRAF_IS_IPV4) {
2407 (void) ip_find_hdr_v4((ipha_t *)rptr, &ipp,
2408 B_FALSE);
2409 } else {
2410 uint8_t nexthdrp;
2411
2412 /*
2413 * IPv6 packets can only be received by applications
2414 * that are prepared to receive IPv6 addresses.
2415 * The IP fanout must ensure this.
2416 */
2417 ASSERT(connp->conn_family == AF_INET6);
2418
2419 (void) ip_find_hdr_v6(mp, (ip6_t *)rptr, B_TRUE, &ipp,
2420 &nexthdrp);
2421 ASSERT(nexthdrp == IPPROTO_TCP);
2422
2423 /* Could have caused a pullup? */
2424 iphdr = mp->b_rptr;
2425 rptr = mp->b_rptr;
2426 }
2427 }
2428 ASSERT(DB_TYPE(mp) == M_DATA);
2429 ASSERT(mp->b_next == NULL);
2430
2431 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2432 seg_seq = ntohl(tcpha->tha_seq);
2433 seg_ack = ntohl(tcpha->tha_ack);
2434 ASSERT((uintptr_t)(mp->b_wptr - rptr) <= (uintptr_t)INT_MAX);
2435 seg_len = (int)(mp->b_wptr - rptr) -
2436 (ip_hdr_len + TCP_HDR_LENGTH(tcpha));
2437 if ((mp1 = mp->b_cont) != NULL && mp1->b_datap->db_type == M_DATA) {
2438 do {
2439 ASSERT((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <=
2440 (uintptr_t)INT_MAX);
2441 seg_len += (int)(mp1->b_wptr - mp1->b_rptr);
2442 } while ((mp1 = mp1->b_cont) != NULL &&
2443 mp1->b_datap->db_type == M_DATA);
2444 }
2445
2446 DTRACE_TCP5(receive, mblk_t *, NULL, ip_xmit_attr_t *, connp->conn_ixa,
2447 __dtrace_tcp_void_ip_t *, iphdr, tcp_t *, tcp,
2448 __dtrace_tcp_tcph_t *, tcpha);
2449
2450 if (tcp->tcp_state == TCPS_TIME_WAIT) {
2451 tcp_time_wait_processing(tcp, mp, seg_seq, seg_ack,
2452 seg_len, tcpha, ira);
2453 return;
2454 }
2455
2456 if (sqp != NULL) {
2457 /*
2458 * This is the correct place to update tcp_last_recv_time. Note
2459 * that it is also updated for tcp structure that belongs to
2460 * global and listener queues which do not really need updating.
2461 * But that should not cause any harm. And it is updated for
2462 * all kinds of incoming segments, not only for data segments.
2463 */
2464 tcp->tcp_last_recv_time = LBOLT_FASTPATH;
2465 }
2466
2467 flags = (unsigned int)tcpha->tha_flags & 0xFF;
2468
2469 BUMP_LOCAL(tcp->tcp_ibsegs);
2470 DTRACE_PROBE2(tcp__trace__recv, mblk_t *, mp, tcp_t *, tcp);
2471
2472 if ((flags & TH_URG) && sqp != NULL) {
2473 /*
2474 * TCP can't handle urgent pointers that arrive before
2475 * the connection has been accept()ed since it can't
2476 * buffer OOB data. Discard segment if this happens.
2477 *
2478 * We can't just rely on a non-null tcp_listener to indicate
2479 * that the accept() has completed since unlinking of the
2480 * eager and completion of the accept are not atomic.
2481 * tcp_detached, when it is not set (B_FALSE) indicates
2482 * that the accept() has completed.
2483 *
2484 * Nor can it reassemble urgent pointers, so discard
2485 * if it's not the next segment expected.
2486 *
2487 * Otherwise, collapse chain into one mblk (discard if
2488 * that fails). This makes sure the headers, retransmitted
2489 * data, and new data all are in the same mblk.
2490 */
2491 ASSERT(mp != NULL);
2492 if (tcp->tcp_detached || !pullupmsg(mp, -1)) {
2493 freemsg(mp);
2494 return;
2495 }
2496 /* Update pointers into message */
2497 iphdr = rptr = mp->b_rptr;
2498 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2499 if (SEQ_GT(seg_seq, tcp->tcp_rnxt)) {
2500 /*
2501 * Since we can't handle any data with this urgent
2502 * pointer that is out of sequence, we expunge
2503 * the data. This allows us to still register
2504 * the urgent mark and generate the M_PCSIG,
2505 * which we can do.
2506 */
2507 mp->b_wptr = (uchar_t *)tcpha + TCP_HDR_LENGTH(tcpha);
2508 seg_len = 0;
2509 }
2510 }
2511
2512 sockupcalls = connp->conn_upcalls;
2513 /* A conn_t may have belonged to a now-closed socket. Be careful. */
2514 if (sockupcalls == NULL)
2515 sockupcalls = &tcp_dummy_upcalls;
2516
2517 switch (tcp->tcp_state) {
2518 case TCPS_SYN_SENT:
2519 if (connp->conn_final_sqp == NULL &&
2520 tcp_outbound_squeue_switch && sqp != NULL) {
2521 ASSERT(connp->conn_initial_sqp == connp->conn_sqp);
2522 connp->conn_final_sqp = sqp;
2523 if (connp->conn_final_sqp != connp->conn_sqp) {
2524 DTRACE_PROBE1(conn__final__sqp__switch,
2525 conn_t *, connp);
2526 CONN_INC_REF(connp);
2527 SQUEUE_SWITCH(connp, connp->conn_final_sqp);
2528 SQUEUE_ENTER_ONE(connp->conn_sqp, mp,
2529 tcp_input_data, connp, ira, ip_squeue_flag,
2530 SQTAG_CONNECT_FINISH);
2531 return;
2532 }
2533 DTRACE_PROBE1(conn__final__sqp__same, conn_t *, connp);
2534 }
2535 if (flags & TH_ACK) {
2536 /*
2537 * Note that our stack cannot send data before a
2538 * connection is established, therefore the
2539 * following check is valid. Otherwise, it has
2540 * to be changed.
2541 */
2542 if (SEQ_LEQ(seg_ack, tcp->tcp_iss) ||
2543 SEQ_GT(seg_ack, tcp->tcp_snxt)) {
2544 freemsg(mp);
2545 if (flags & TH_RST)
2546 return;
2547 tcp_xmit_ctl("TCPS_SYN_SENT-Bad_seq",
2548 tcp, seg_ack, 0, TH_RST);
2549 return;
2550 }
2551 ASSERT(tcp->tcp_suna + 1 == seg_ack);
2552 }
2553 if (flags & TH_RST) {
2554 if (flags & TH_ACK) {
2555 DTRACE_TCP5(connect__refused, mblk_t *, NULL,
2556 ip_xmit_attr_t *, connp->conn_ixa,
2557 void_ip_t *, iphdr, tcp_t *, tcp,
2558 tcph_t *, tcpha);
2559 (void) tcp_clean_death(tcp, ECONNREFUSED);
2560 }
2561 freemsg(mp);
2562 return;
2563 }
2564 if (!(flags & TH_SYN)) {
2565 freemsg(mp);
2566 return;
2567 }
2568
2569 /* Process all TCP options. */
2570 tcp_process_options(tcp, tcpha);
2571 /*
2572 * The following changes our rwnd to be a multiple of the
2573 * MIN(peer MSS, our MSS) for performance reason.
2574 */
2575 (void) tcp_rwnd_set(tcp, MSS_ROUNDUP(connp->conn_rcvbuf,
2576 tcp->tcp_mss));
2577
2578 /* Is the other end ECN capable? */
2579 if (tcp->tcp_ecn_ok) {
2580 if ((flags & (TH_ECE|TH_CWR)) != TH_ECE) {
2581 tcp->tcp_ecn_ok = B_FALSE;
2582 }
2583 }
2584 /*
2585 * Clear ECN flags because it may interfere with later
2586 * processing.
2587 */
2588 flags &= ~(TH_ECE|TH_CWR);
2589
2590 tcp->tcp_irs = seg_seq;
2591 tcp->tcp_rack = seg_seq;
2592 tcp->tcp_rnxt = seg_seq + 1;
2593 tcp->tcp_tcpha->tha_ack = htonl(tcp->tcp_rnxt);
2594 if (!TCP_IS_DETACHED(tcp)) {
2595 /* Allocate room for SACK options if needed. */
2596 connp->conn_wroff = connp->conn_ht_iphc_len;
2597 if (tcp->tcp_snd_sack_ok)
2598 connp->conn_wroff += TCPOPT_MAX_SACK_LEN;
2599 if (!tcp->tcp_loopback)
2600 connp->conn_wroff += tcps->tcps_wroff_xtra;
2601
2602 (void) proto_set_tx_wroff(connp->conn_rq, connp,
2603 connp->conn_wroff);
2604 }
2605 if (flags & TH_ACK) {
2606 /*
2607 * If we can't get the confirmation upstream, pretend
2608 * we didn't even see this one.
2609 *
2610 * XXX: how can we pretend we didn't see it if we
2611 * have updated rnxt et. al.
2612 *
2613 * For loopback we defer sending up the T_CONN_CON
2614 * until after some checks below.
2615 */
2616 mp1 = NULL;
2617 /*
2618 * tcp_sendmsg() checks tcp_state without entering
2619 * the squeue so tcp_state should be updated before
2620 * sending up connection confirmation. Probe the
2621 * state change below when we are sure the connection
2622 * confirmation has been sent.
2623 */
2624 tcp->tcp_state = TCPS_ESTABLISHED;
2625 if (!tcp_conn_con(tcp, iphdr, mp,
2626 tcp->tcp_loopback ? &mp1 : NULL, ira)) {
2627 tcp->tcp_state = TCPS_SYN_SENT;
2628 freemsg(mp);
2629 return;
2630 }
2631 TCPS_CONN_INC(tcps);
2632 /* SYN was acked - making progress */
2633 tcp->tcp_ip_forward_progress = B_TRUE;
2634
2635 /* One for the SYN */
2636 tcp->tcp_suna = tcp->tcp_iss + 1;
2637 tcp->tcp_valid_bits &= ~TCP_ISS_VALID;
2638
2639 /*
2640 * If SYN was retransmitted, need to reset all
2641 * retransmission info. This is because this
2642 * segment will be treated as a dup ACK.
2643 */
2644 if (tcp->tcp_rexmit) {
2645 tcp->tcp_rexmit = B_FALSE;
2646 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
2647 tcp->tcp_rexmit_max = tcp->tcp_snxt;
2648 tcp->tcp_ms_we_have_waited = 0;
2649
2650 /*
2651 * Set tcp_cwnd back to 1 MSS, per
2652 * recommendation from
2653 * draft-floyd-incr-init-win-01.txt,
2654 * Increasing TCP's Initial Window.
2655 */
2656 tcp->tcp_cwnd = tcp->tcp_mss;
2657 }
2658
2659 tcp->tcp_swl1 = seg_seq;
2660 tcp->tcp_swl2 = seg_ack;
2661
2662 new_swnd = ntohs(tcpha->tha_win);
2663 tcp->tcp_swnd = new_swnd;
2664 if (new_swnd > tcp->tcp_max_swnd)
2665 tcp->tcp_max_swnd = new_swnd;
2666
2667 /*
2668 * Always send the three-way handshake ack immediately
2669 * in order to make the connection complete as soon as
2670 * possible on the accepting host.
2671 */
2672 flags |= TH_ACK_NEEDED;
2673
2674 /*
2675 * Trace connect-established here.
2676 */
2677 DTRACE_TCP5(connect__established, mblk_t *, NULL,
2678 ip_xmit_attr_t *, tcp->tcp_connp->conn_ixa,
2679 void_ip_t *, iphdr, tcp_t *, tcp, tcph_t *, tcpha);
2680
2681 /* Trace change from SYN_SENT -> ESTABLISHED here */
2682 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
2683 connp->conn_ixa, void, NULL, tcp_t *, tcp,
2684 void, NULL, int32_t, TCPS_SYN_SENT);
2685
2686 /*
2687 * Special case for loopback. At this point we have
2688 * received SYN-ACK from the remote endpoint. In
2689 * order to ensure that both endpoints reach the
2690 * fused state prior to any data exchange, the final
2691 * ACK needs to be sent before we indicate T_CONN_CON
2692 * to the module upstream.
2693 */
2694 if (tcp->tcp_loopback) {
2695 mblk_t *ack_mp;
2696
2697 ASSERT(!tcp->tcp_unfusable);
2698 ASSERT(mp1 != NULL);
2699 /*
2700 * For loopback, we always get a pure SYN-ACK
2701 * and only need to send back the final ACK
2702 * with no data (this is because the other
2703 * tcp is ours and we don't do T/TCP). This
2704 * final ACK triggers the passive side to
2705 * perform fusion in ESTABLISHED state.
2706 */
2707 if ((ack_mp = tcp_ack_mp(tcp)) != NULL) {
2708 if (tcp->tcp_ack_tid != 0) {
2709 (void) TCP_TIMER_CANCEL(tcp,
2710 tcp->tcp_ack_tid);
2711 tcp->tcp_ack_tid = 0;
2712 }
2713 tcp_send_data(tcp, ack_mp);
2714 BUMP_LOCAL(tcp->tcp_obsegs);
2715 TCPS_BUMP_MIB(tcps, tcpOutAck);
2716
2717 if (!IPCL_IS_NONSTR(connp)) {
2718 /* Send up T_CONN_CON */
2719 if (ira->ira_cred != NULL) {
2720 mblk_setcred(mp1,
2721 ira->ira_cred,
2722 ira->ira_cpid);
2723 }
2724 putnext(connp->conn_rq, mp1);
2725 } else {
2726 (*sockupcalls->su_connected)
2727 (connp->conn_upper_handle,
2728 tcp->tcp_connid,
2729 ira->ira_cred,
2730 ira->ira_cpid);
2731 freemsg(mp1);
2732 }
2733
2734 freemsg(mp);
2735 return;
2736 }
2737 /*
2738 * Forget fusion; we need to handle more
2739 * complex cases below. Send the deferred
2740 * T_CONN_CON message upstream and proceed
2741 * as usual. Mark this tcp as not capable
2742 * of fusion.
2743 */
2744 TCP_STAT(tcps, tcp_fusion_unfusable);
2745 tcp->tcp_unfusable = B_TRUE;
2746 if (!IPCL_IS_NONSTR(connp)) {
2747 if (ira->ira_cred != NULL) {
2748 mblk_setcred(mp1, ira->ira_cred,
2749 ira->ira_cpid);
2750 }
2751 putnext(connp->conn_rq, mp1);
2752 } else {
2753 (*sockupcalls->su_connected)
2754 (connp->conn_upper_handle,
2755 tcp->tcp_connid, ira->ira_cred,
2756 ira->ira_cpid);
2757 freemsg(mp1);
2758 }
2759 }
2760
2761 /*
2762 * Check to see if there is data to be sent. If
2763 * yes, set the transmit flag. Then check to see
2764 * if received data processing needs to be done.
2765 * If not, go straight to xmit_check. This short
2766 * cut is OK as we don't support T/TCP.
2767 */
2768 if (tcp->tcp_unsent)
2769 flags |= TH_XMIT_NEEDED;
2770
2771 if (seg_len == 0 && !(flags & TH_URG)) {
2772 freemsg(mp);
2773 goto xmit_check;
2774 }
2775
2776 flags &= ~TH_SYN;
2777 seg_seq++;
2778 break;
2779 }
2780 tcp->tcp_state = TCPS_SYN_RCVD;
2781 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
2782 connp->conn_ixa, void_ip_t *, NULL, tcp_t *, tcp,
2783 tcph_t *, NULL, int32_t, TCPS_SYN_SENT);
2784 mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, tcp->tcp_mss,
2785 NULL, NULL, tcp->tcp_iss, B_FALSE, NULL, B_FALSE);
2786 if (mp1 != NULL) {
2787 tcp_send_data(tcp, mp1);
2788 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
2789 }
2790 freemsg(mp);
2791 return;
2792 case TCPS_SYN_RCVD:
2793 if (flags & TH_ACK) {
2794 uint32_t pinit_wnd;
2795
2796 /*
2797 * In this state, a SYN|ACK packet is either bogus
2798 * because the other side must be ACKing our SYN which
2799 * indicates it has seen the ACK for their SYN and
2800 * shouldn't retransmit it or we're crossing SYNs
2801 * on active open.
2802 */
2803 if ((flags & TH_SYN) && !tcp->tcp_active_open) {
2804 freemsg(mp);
2805 tcp_xmit_ctl("TCPS_SYN_RCVD-bad_syn",
2806 tcp, seg_ack, 0, TH_RST);
2807 return;
2808 }
2809 /*
2810 * NOTE: RFC 793 pg. 72 says this should be
2811 * tcp->tcp_suna <= seg_ack <= tcp->tcp_snxt
2812 * but that would mean we have an ack that ignored
2813 * our SYN.
2814 */
2815 if (SEQ_LEQ(seg_ack, tcp->tcp_suna) ||
2816 SEQ_GT(seg_ack, tcp->tcp_snxt)) {
2817 freemsg(mp);
2818 tcp_xmit_ctl("TCPS_SYN_RCVD-bad_ack",
2819 tcp, seg_ack, 0, TH_RST);
2820 return;
2821 }
2822 /*
2823 * No sane TCP stack will send such a small window
2824 * without receiving any data. Just drop this invalid
2825 * ACK. We also shorten the abort timeout in case
2826 * this is an attack.
2827 */
2828 pinit_wnd = ntohs(tcpha->tha_win) << tcp->tcp_snd_ws;
2829 if (pinit_wnd < tcp->tcp_mss &&
2830 pinit_wnd < tcp_init_wnd_chk) {
2831 freemsg(mp);
2832 TCP_STAT(tcps, tcp_zwin_ack_syn);
2833 tcp->tcp_second_ctimer_threshold =
2834 tcp_early_abort * SECONDS;
2835 return;
2836 }
2837 }
2838 break;
2839 case TCPS_LISTEN:
2840 /*
2841 * Only a TLI listener can come through this path when a
2842 * acceptor is going back to be a listener and a packet
2843 * for the acceptor hits the classifier. For a socket
2844 * listener, this can never happen because a listener
2845 * can never accept connection on itself and hence a
2846 * socket acceptor can not go back to being a listener.
2847 */
2848 ASSERT(!TCP_IS_SOCKET(tcp));
2849 /*FALLTHRU*/
2850 case TCPS_CLOSED:
2851 case TCPS_BOUND: {
2852 conn_t *new_connp;
2853 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
2854
2855 /*
2856 * Don't accept any input on a closed tcp as this TCP logically
2857 * does not exist on the system. Don't proceed further with
2858 * this TCP. For instance, this packet could trigger another
2859 * close of this tcp which would be disastrous for tcp_refcnt.
2860 * tcp_close_detached / tcp_clean_death / tcp_closei_local must
2861 * be called at most once on a TCP. In this case we need to
2862 * refeed the packet into the classifier and figure out where
2863 * the packet should go.
2864 */
2865 new_connp = ipcl_classify(mp, ira, ipst);
2866 if (new_connp != NULL) {
2867 /* Drops ref on new_connp */
2868 tcp_reinput(new_connp, mp, ira, ipst);
2869 return;
2870 }
2871 /* We failed to classify. For now just drop the packet */
2872 freemsg(mp);
2873 return;
2874 }
2875 case TCPS_IDLE:
2876 /*
2877 * Handle the case where the tcp_clean_death() has happened
2878 * on a connection (application hasn't closed yet) but a packet
2879 * was already queued on squeue before tcp_clean_death()
2880 * was processed. Calling tcp_clean_death() twice on same
2881 * connection can result in weird behaviour.
2882 */
2883 freemsg(mp);
2884 return;
2885 default:
2886 break;
2887 }
2888
2889 /*
2890 * Already on the correct queue/perimeter.
2891 * If this is a detached connection and not an eager
2892 * connection hanging off a listener then new data
2893 * (past the FIN) will cause a reset.
2894 * We do a special check here where it
2895 * is out of the main line, rather than check
2896 * if we are detached every time we see new
2897 * data down below.
2898 */
2899 if (TCP_IS_DETACHED_NONEAGER(tcp) &&
2900 (seg_len > 0 && SEQ_GT(seg_seq + seg_len, tcp->tcp_rnxt))) {
2901 TCPS_BUMP_MIB(tcps, tcpInClosed);
2902 DTRACE_PROBE2(tcp__trace__recv, mblk_t *, mp, tcp_t *, tcp);
2903 freemsg(mp);
2904 tcp_xmit_ctl("new data when detached", tcp,
2905 tcp->tcp_snxt, 0, TH_RST);
2906 (void) tcp_clean_death(tcp, EPROTO);
2907 return;
2908 }
2909
2910 mp->b_rptr = (uchar_t *)tcpha + TCP_HDR_LENGTH(tcpha);
2911 urp = ntohs(tcpha->tha_urp) - TCP_OLD_URP_INTERPRETATION;
2912 new_swnd = ntohs(tcpha->tha_win) <<
2913 ((tcpha->tha_flags & TH_SYN) ? 0 : tcp->tcp_snd_ws);
2914
2915 if (tcp->tcp_snd_ts_ok) {
2916 if (!tcp_paws_check(tcp, tcpha, &tcpopt)) {
2917 /*
2918 * This segment is not acceptable.
2919 * Drop it and send back an ACK.
2920 */
2921 freemsg(mp);
2922 flags |= TH_ACK_NEEDED;
2923 goto ack_check;
2924 }
2925 } else if (tcp->tcp_snd_sack_ok) {
2926 tcpopt.tcp = tcp;
2927 /*
2928 * SACK info in already updated in tcp_parse_options. Ignore
2929 * all other TCP options...
2930 */
2931 (void) tcp_parse_options(tcpha, &tcpopt);
2932 }
2933 try_again:;
2934 mss = tcp->tcp_mss;
2935 gap = seg_seq - tcp->tcp_rnxt;
2936 rgap = tcp->tcp_rwnd - (gap + seg_len);
2937 /*
2938 * gap is the amount of sequence space between what we expect to see
2939 * and what we got for seg_seq. A positive value for gap means
2940 * something got lost. A negative value means we got some old stuff.
2941 */
2942 if (gap < 0) {
2943 /* Old stuff present. Is the SYN in there? */
2944 if (seg_seq == tcp->tcp_irs && (flags & TH_SYN) &&
2945 (seg_len != 0)) {
2946 flags &= ~TH_SYN;
2947 seg_seq++;
2948 urp--;
2949 /* Recompute the gaps after noting the SYN. */
2950 goto try_again;
2951 }
2952 TCPS_BUMP_MIB(tcps, tcpInDataDupSegs);
2953 TCPS_UPDATE_MIB(tcps, tcpInDataDupBytes,
2954 (seg_len > -gap ? -gap : seg_len));
2955 /* Remove the old stuff from seg_len. */
2956 seg_len += gap;
2957 /*
2958 * Anything left?
2959 * Make sure to check for unack'd FIN when rest of data
2960 * has been previously ack'd.
2961 */
2962 if (seg_len < 0 || (seg_len == 0 && !(flags & TH_FIN))) {
2963 /*
2964 * Resets are only valid if they lie within our offered
2965 * window. If the RST bit is set, we just ignore this
2966 * segment.
2967 */
2968 if (flags & TH_RST) {
2969 freemsg(mp);
2970 return;
2971 }
2972
2973 /*
2974 * The arriving of dup data packets indicate that we
2975 * may have postponed an ack for too long, or the other
2976 * side's RTT estimate is out of shape. Start acking
2977 * more often.
2978 */
2979 if (SEQ_GEQ(seg_seq + seg_len - gap, tcp->tcp_rack) &&
2980 tcp->tcp_rack_cnt >= 1 &&
2981 tcp->tcp_rack_abs_max > 2) {
2982 tcp->tcp_rack_abs_max--;
2983 }
2984 tcp->tcp_rack_cur_max = 1;
2985
2986 /*
2987 * This segment is "unacceptable". None of its
2988 * sequence space lies within our advertized window.
2989 *
2990 * Adjust seg_len to the original value for tracing.
2991 */
2992 seg_len -= gap;
2993 if (connp->conn_debug) {
2994 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
2995 "tcp_rput: unacceptable, gap %d, rgap %d, "
2996 "flags 0x%x, seg_seq %u, seg_ack %u, "
2997 "seg_len %d, rnxt %u, snxt %u, %s",
2998 gap, rgap, flags, seg_seq, seg_ack,
2999 seg_len, tcp->tcp_rnxt, tcp->tcp_snxt,
3000 tcp_display(tcp, NULL,
3001 DISP_ADDR_AND_PORT));
3002 }
3003
3004 /*
3005 * Arrange to send an ACK in response to the
3006 * unacceptable segment per RFC 793 page 69. There
3007 * is only one small difference between ours and the
3008 * acceptability test in the RFC - we accept ACK-only
3009 * packet with SEG.SEQ = RCV.NXT+RCV.WND and no ACK
3010 * will be generated.
3011 *
3012 * Note that we have to ACK an ACK-only packet at least
3013 * for stacks that send 0-length keep-alives with
3014 * SEG.SEQ = SND.NXT-1 as recommended by RFC1122,
3015 * section 4.2.3.6. As long as we don't ever generate
3016 * an unacceptable packet in response to an incoming
3017 * packet that is unacceptable, it should not cause
3018 * "ACK wars".
3019 */
3020 flags |= TH_ACK_NEEDED;
3021
3022 /*
3023 * Continue processing this segment in order to use the
3024 * ACK information it contains, but skip all other
3025 * sequence-number processing. Processing the ACK
3026 * information is necessary in order to
3027 * re-synchronize connections that may have lost
3028 * synchronization.
3029 *
3030 * We clear seg_len and flag fields related to
3031 * sequence number processing as they are not
3032 * to be trusted for an unacceptable segment.
3033 */
3034 seg_len = 0;
3035 flags &= ~(TH_SYN | TH_FIN | TH_URG);
3036 goto process_ack;
3037 }
3038
3039 /* Fix seg_seq, and chew the gap off the front. */
3040 seg_seq = tcp->tcp_rnxt;
3041 urp += gap;
3042 do {
3043 mblk_t *mp2;
3044 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
3045 (uintptr_t)UINT_MAX);
3046 gap += (uint_t)(mp->b_wptr - mp->b_rptr);
3047 if (gap > 0) {
3048 mp->b_rptr = mp->b_wptr - gap;
3049 break;
3050 }
3051 mp2 = mp;
3052 mp = mp->b_cont;
3053 freeb(mp2);
3054 } while (gap < 0);
3055 /*
3056 * If the urgent data has already been acknowledged, we
3057 * should ignore TH_URG below
3058 */
3059 if (urp < 0)
3060 flags &= ~TH_URG;
3061 }
3062 /*
3063 * rgap is the amount of stuff received out of window. A negative
3064 * value is the amount out of window.
3065 */
3066 if (rgap < 0) {
3067 mblk_t *mp2;
3068
3069 if (tcp->tcp_rwnd == 0) {
3070 TCPS_BUMP_MIB(tcps, tcpInWinProbe);
3071 } else {
3072 TCPS_BUMP_MIB(tcps, tcpInDataPastWinSegs);
3073 TCPS_UPDATE_MIB(tcps, tcpInDataPastWinBytes, -rgap);
3074 }
3075
3076 /*
3077 * seg_len does not include the FIN, so if more than
3078 * just the FIN is out of window, we act like we don't
3079 * see it. (If just the FIN is out of window, rgap
3080 * will be zero and we will go ahead and acknowledge
3081 * the FIN.)
3082 */
3083 flags &= ~TH_FIN;
3084
3085 /* Fix seg_len and make sure there is something left. */
3086 seg_len += rgap;
3087 if (seg_len <= 0) {
3088 /*
3089 * Resets are only valid if they lie within our offered
3090 * window. If the RST bit is set, we just ignore this
3091 * segment.
3092 */
3093 if (flags & TH_RST) {
3094 freemsg(mp);
3095 return;
3096 }
3097
3098 /* Per RFC 793, we need to send back an ACK. */
3099 flags |= TH_ACK_NEEDED;
3100
3101 /*
3102 * Send SIGURG as soon as possible i.e. even
3103 * if the TH_URG was delivered in a window probe
3104 * packet (which will be unacceptable).
3105 *
3106 * We generate a signal if none has been generated
3107 * for this connection or if this is a new urgent
3108 * byte. Also send a zero-length "unmarked" message
3109 * to inform SIOCATMARK that this is not the mark.
3110 *
3111 * tcp_urp_last_valid is cleared when the T_exdata_ind
3112 * is sent up. This plus the check for old data
3113 * (gap >= 0) handles the wraparound of the sequence
3114 * number space without having to always track the
3115 * correct MAX(tcp_urp_last, tcp_rnxt). (BSD tracks
3116 * this max in its rcv_up variable).
3117 *
3118 * This prevents duplicate SIGURGS due to a "late"
3119 * zero-window probe when the T_EXDATA_IND has already
3120 * been sent up.
3121 */
3122 if ((flags & TH_URG) &&
3123 (!tcp->tcp_urp_last_valid || SEQ_GT(urp + seg_seq,
3124 tcp->tcp_urp_last))) {
3125 if (IPCL_IS_NONSTR(connp)) {
3126 if (!TCP_IS_DETACHED(tcp)) {
3127 (*sockupcalls->su_signal_oob)
3128 (connp->conn_upper_handle,
3129 urp);
3130 }
3131 } else {
3132 mp1 = allocb(0, BPRI_MED);
3133 if (mp1 == NULL) {
3134 freemsg(mp);
3135 return;
3136 }
3137 if (!TCP_IS_DETACHED(tcp) &&
3138 !putnextctl1(connp->conn_rq,
3139 M_PCSIG, SIGURG)) {
3140 /* Try again on the rexmit. */
3141 freemsg(mp1);
3142 freemsg(mp);
3143 return;
3144 }
3145 /*
3146 * If the next byte would be the mark
3147 * then mark with MARKNEXT else mark
3148 * with NOTMARKNEXT.
3149 */
3150 if (gap == 0 && urp == 0)
3151 mp1->b_flag |= MSGMARKNEXT;
3152 else
3153 mp1->b_flag |= MSGNOTMARKNEXT;
3154 freemsg(tcp->tcp_urp_mark_mp);
3155 tcp->tcp_urp_mark_mp = mp1;
3156 flags |= TH_SEND_URP_MARK;
3157 }
3158 tcp->tcp_urp_last_valid = B_TRUE;
3159 tcp->tcp_urp_last = urp + seg_seq;
3160 }
3161 /*
3162 * If this is a zero window probe, continue to
3163 * process the ACK part. But we need to set seg_len
3164 * to 0 to avoid data processing. Otherwise just
3165 * drop the segment and send back an ACK.
3166 */
3167 if (tcp->tcp_rwnd == 0 && seg_seq == tcp->tcp_rnxt) {
3168 flags &= ~(TH_SYN | TH_URG);
3169 seg_len = 0;
3170 goto process_ack;
3171 } else {
3172 freemsg(mp);
3173 goto ack_check;
3174 }
3175 }
3176 /* Pitch out of window stuff off the end. */
3177 rgap = seg_len;
3178 mp2 = mp;
3179 do {
3180 ASSERT((uintptr_t)(mp2->b_wptr - mp2->b_rptr) <=
3181 (uintptr_t)INT_MAX);
3182 rgap -= (int)(mp2->b_wptr - mp2->b_rptr);
3183 if (rgap < 0) {
3184 mp2->b_wptr += rgap;
3185 if ((mp1 = mp2->b_cont) != NULL) {
3186 mp2->b_cont = NULL;
3187 freemsg(mp1);
3188 }
3189 break;
3190 }
3191 } while ((mp2 = mp2->b_cont) != NULL);
3192 }
3193 ok:;
3194 /*
3195 * TCP should check ECN info for segments inside the window only.
3196 * Therefore the check should be done here.
3197 */
3198 if (tcp->tcp_ecn_ok) {
3199 if (flags & TH_CWR) {
3200 tcp->tcp_ecn_echo_on = B_FALSE;
3201 }
3202 /*
3203 * Note that both ECN_CE and CWR can be set in the
3204 * same segment. In this case, we once again turn
3205 * on ECN_ECHO.
3206 */
3207 if (connp->conn_ipversion == IPV4_VERSION) {
3208 uchar_t tos = ((ipha_t *)rptr)->ipha_type_of_service;
3209
3210 if ((tos & IPH_ECN_CE) == IPH_ECN_CE) {
3211 tcp->tcp_ecn_echo_on = B_TRUE;
3212 }
3213 } else {
3214 uint32_t vcf = ((ip6_t *)rptr)->ip6_vcf;
3215
3216 if ((vcf & htonl(IPH_ECN_CE << 20)) ==
3217 htonl(IPH_ECN_CE << 20)) {
3218 tcp->tcp_ecn_echo_on = B_TRUE;
3219 }
3220 }
3221 }
3222
3223 /*
3224 * Check whether we can update tcp_ts_recent. This test is
3225 * NOT the one in RFC 1323 3.4. It is from Braden, 1993, "TCP
3226 * Extensions for High Performance: An Update", Internet Draft.
3227 */
3228 if (tcp->tcp_snd_ts_ok &&
3229 TSTMP_GEQ(tcpopt.tcp_opt_ts_val, tcp->tcp_ts_recent) &&
3230 SEQ_LEQ(seg_seq, tcp->tcp_rack)) {
3231 tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val;
3232 tcp->tcp_last_rcv_lbolt = LBOLT_FASTPATH64;
3233 }
3234
3235 if (seg_seq != tcp->tcp_rnxt || tcp->tcp_reass_head) {
3236 /*
3237 * FIN in an out of order segment. We record this in
3238 * tcp_valid_bits and the seq num of FIN in tcp_ofo_fin_seq.
3239 * Clear the FIN so that any check on FIN flag will fail.
3240 * Remember that FIN also counts in the sequence number
3241 * space. So we need to ack out of order FIN only segments.
3242 */
3243 if (flags & TH_FIN) {
3244 tcp->tcp_valid_bits |= TCP_OFO_FIN_VALID;
3245 tcp->tcp_ofo_fin_seq = seg_seq + seg_len;
3246 flags &= ~TH_FIN;
3247 flags |= TH_ACK_NEEDED;
3248 }
3249 if (seg_len > 0) {
3250 /* Fill in the SACK blk list. */
3251 if (tcp->tcp_snd_sack_ok) {
3252 tcp_sack_insert(tcp->tcp_sack_list,
3253 seg_seq, seg_seq + seg_len,
3254 &(tcp->tcp_num_sack_blk));
3255 }
3256
3257 /*
3258 * Attempt reassembly and see if we have something
3259 * ready to go.
3260 */
3261 mp = tcp_reass(tcp, mp, seg_seq);
3262 /* Always ack out of order packets */
3263 flags |= TH_ACK_NEEDED | TH_PUSH;
3264 if (mp) {
3265 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
3266 (uintptr_t)INT_MAX);
3267 seg_len = mp->b_cont ? msgdsize(mp) :
3268 (int)(mp->b_wptr - mp->b_rptr);
3269 seg_seq = tcp->tcp_rnxt;
3270 /*
3271 * A gap is filled and the seq num and len
3272 * of the gap match that of a previously
3273 * received FIN, put the FIN flag back in.
3274 */
3275 if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) &&
3276 seg_seq + seg_len == tcp->tcp_ofo_fin_seq) {
3277 flags |= TH_FIN;
3278 tcp->tcp_valid_bits &=
3279 ~TCP_OFO_FIN_VALID;
3280 }
3281 if (tcp->tcp_reass_tid != 0) {
3282 (void) TCP_TIMER_CANCEL(tcp,
3283 tcp->tcp_reass_tid);
3284 /*
3285 * Restart the timer if there is still
3286 * data in the reassembly queue.
3287 */
3288 if (tcp->tcp_reass_head != NULL) {
3289 tcp->tcp_reass_tid = TCP_TIMER(
3290 tcp, tcp_reass_timer,
3291 tcps->tcps_reass_timeout);
3292 } else {
3293 tcp->tcp_reass_tid = 0;
3294 }
3295 }
3296 } else {
3297 /*
3298 * Keep going even with NULL mp.
3299 * There may be a useful ACK or something else
3300 * we don't want to miss.
3301 *
3302 * But TCP should not perform fast retransmit
3303 * because of the ack number. TCP uses
3304 * seg_len == 0 to determine if it is a pure
3305 * ACK. And this is not a pure ACK.
3306 */
3307 seg_len = 0;
3308 ofo_seg = B_TRUE;
3309
3310 if (tcps->tcps_reass_timeout != 0 &&
3311 tcp->tcp_reass_tid == 0) {
3312 tcp->tcp_reass_tid = TCP_TIMER(tcp,
3313 tcp_reass_timer,
3314 tcps->tcps_reass_timeout);
3315 }
3316 }
3317 }
3318 } else if (seg_len > 0) {
3319 TCPS_BUMP_MIB(tcps, tcpInDataInorderSegs);
3320 TCPS_UPDATE_MIB(tcps, tcpInDataInorderBytes, seg_len);
3321 /*
3322 * If an out of order FIN was received before, and the seq
3323 * num and len of the new segment match that of the FIN,
3324 * put the FIN flag back in.
3325 */
3326 if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) &&
3327 seg_seq + seg_len == tcp->tcp_ofo_fin_seq) {
3328 flags |= TH_FIN;
3329 tcp->tcp_valid_bits &= ~TCP_OFO_FIN_VALID;
3330 }
3331 }
3332 if ((flags & (TH_RST | TH_SYN | TH_URG | TH_ACK)) != TH_ACK) {
3333 if (flags & TH_RST) {
3334 freemsg(mp);
3335 switch (tcp->tcp_state) {
3336 case TCPS_SYN_RCVD:
3337 (void) tcp_clean_death(tcp, ECONNREFUSED);
3338 break;
3339 case TCPS_ESTABLISHED:
3340 case TCPS_FIN_WAIT_1:
3341 case TCPS_FIN_WAIT_2:
3342 case TCPS_CLOSE_WAIT:
3343 (void) tcp_clean_death(tcp, ECONNRESET);
3344 break;
3345 case TCPS_CLOSING:
3346 case TCPS_LAST_ACK:
3347 (void) tcp_clean_death(tcp, 0);
3348 break;
3349 default:
3350 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
3351 (void) tcp_clean_death(tcp, ENXIO);
3352 break;
3353 }
3354 return;
3355 }
3356 if (flags & TH_SYN) {
3357 /*
3358 * See RFC 793, Page 71
3359 *
3360 * The seq number must be in the window as it should
3361 * be "fixed" above. If it is outside window, it should
3362 * be already rejected. Note that we allow seg_seq to be
3363 * rnxt + rwnd because we want to accept 0 window probe.
3364 */
3365 ASSERT(SEQ_GEQ(seg_seq, tcp->tcp_rnxt) &&
3366 SEQ_LEQ(seg_seq, tcp->tcp_rnxt + tcp->tcp_rwnd));
3367 freemsg(mp);
3368 /*
3369 * If the ACK flag is not set, just use our snxt as the
3370 * seq number of the RST segment.
3371 */
3372 if (!(flags & TH_ACK)) {
3373 seg_ack = tcp->tcp_snxt;
3374 }
3375 tcp_xmit_ctl("TH_SYN", tcp, seg_ack, seg_seq + 1,
3376 TH_RST|TH_ACK);
3377 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
3378 (void) tcp_clean_death(tcp, ECONNRESET);
3379 return;
3380 }
3381 /*
3382 * urp could be -1 when the urp field in the packet is 0
3383 * and TCP_OLD_URP_INTERPRETATION is set. This implies that the urgent
3384 * byte was at seg_seq - 1, in which case we ignore the urgent flag.
3385 */
3386 if (flags & TH_URG && urp >= 0) {
3387 if (!tcp->tcp_urp_last_valid ||
3388 SEQ_GT(urp + seg_seq, tcp->tcp_urp_last)) {
3389 /*
3390 * Non-STREAMS sockets handle the urgent data a litte
3391 * differently from STREAMS based sockets. There is no
3392 * need to mark any mblks with the MSG{NOT,}MARKNEXT
3393 * flags to keep SIOCATMARK happy. Instead a
3394 * su_signal_oob upcall is made to update the mark.
3395 * Neither is a T_EXDATA_IND mblk needed to be
3396 * prepended to the urgent data. The urgent data is
3397 * delivered using the su_recv upcall, where we set
3398 * the MSG_OOB flag to indicate that it is urg data.
3399 *
3400 * Neither TH_SEND_URP_MARK nor TH_MARKNEXT_NEEDED
3401 * are used by non-STREAMS sockets.
3402 */
3403 if (IPCL_IS_NONSTR(connp)) {
3404 if (!TCP_IS_DETACHED(tcp)) {
3405 (*sockupcalls->su_signal_oob)
3406 (connp->conn_upper_handle, urp);
3407 }
3408 } else {
3409 /*
3410 * If we haven't generated the signal yet for
3411 * this urgent pointer value, do it now. Also,
3412 * send up a zero-length M_DATA indicating
3413 * whether or not this is the mark. The latter
3414 * is not needed when a T_EXDATA_IND is sent up.
3415 * However, if there are allocation failures
3416 * this code relies on the sender retransmitting
3417 * and the socket code for determining the mark
3418 * should not block waiting for the peer to
3419 * transmit. Thus, for simplicity we always
3420 * send up the mark indication.
3421 */
3422 mp1 = allocb(0, BPRI_MED);
3423 if (mp1 == NULL) {
3424 freemsg(mp);
3425 return;
3426 }
3427 if (!TCP_IS_DETACHED(tcp) &&
3428 !putnextctl1(connp->conn_rq, M_PCSIG,
3429 SIGURG)) {
3430 /* Try again on the rexmit. */
3431 freemsg(mp1);
3432 freemsg(mp);
3433 return;
3434 }
3435 /*
3436 * Mark with NOTMARKNEXT for now.
3437 * The code below will change this to MARKNEXT
3438 * if we are at the mark.
3439 *
3440 * If there are allocation failures (e.g. in
3441 * dupmsg below) the next time tcp_input_data
3442 * sees the urgent segment it will send up the
3443 * MSGMARKNEXT message.
3444 */
3445 mp1->b_flag |= MSGNOTMARKNEXT;
3446 freemsg(tcp->tcp_urp_mark_mp);
3447 tcp->tcp_urp_mark_mp = mp1;
3448 flags |= TH_SEND_URP_MARK;
3449 #ifdef DEBUG
3450 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3451 "tcp_rput: sent M_PCSIG 2 seq %x urp %x "
3452 "last %x, %s",
3453 seg_seq, urp, tcp->tcp_urp_last,
3454 tcp_display(tcp, NULL, DISP_PORT_ONLY));
3455 #endif /* DEBUG */
3456 }
3457 tcp->tcp_urp_last_valid = B_TRUE;
3458 tcp->tcp_urp_last = urp + seg_seq;
3459 } else if (tcp->tcp_urp_mark_mp != NULL) {
3460 /*
3461 * An allocation failure prevented the previous
3462 * tcp_input_data from sending up the allocated
3463 * MSG*MARKNEXT message - send it up this time
3464 * around.
3465 */
3466 flags |= TH_SEND_URP_MARK;
3467 }
3468
3469 /*
3470 * If the urgent byte is in this segment, make sure that it is
3471 * all by itself. This makes it much easier to deal with the
3472 * possibility of an allocation failure on the T_exdata_ind.
3473 * Note that seg_len is the number of bytes in the segment, and
3474 * urp is the offset into the segment of the urgent byte.
3475 * urp < seg_len means that the urgent byte is in this segment.
3476 */
3477 if (urp < seg_len) {
3478 if (seg_len != 1) {
3479 uint32_t tmp_rnxt;
3480 /*
3481 * Break it up and feed it back in.
3482 * Re-attach the IP header.
3483 */
3484 mp->b_rptr = iphdr;
3485 if (urp > 0) {
3486 /*
3487 * There is stuff before the urgent
3488 * byte.
3489 */
3490 mp1 = dupmsg(mp);
3491 if (!mp1) {
3492 /*
3493 * Trim from urgent byte on.
3494 * The rest will come back.
3495 */
3496 (void) adjmsg(mp,
3497 urp - seg_len);
3498 tcp_input_data(connp,
3499 mp, NULL, ira);
3500 return;
3501 }
3502 (void) adjmsg(mp1, urp - seg_len);
3503 /* Feed this piece back in. */
3504 tmp_rnxt = tcp->tcp_rnxt;
3505 tcp_input_data(connp, mp1, NULL, ira);
3506 /*
3507 * If the data passed back in was not
3508 * processed (ie: bad ACK) sending
3509 * the remainder back in will cause a
3510 * loop. In this case, drop the
3511 * packet and let the sender try
3512 * sending a good packet.
3513 */
3514 if (tmp_rnxt == tcp->tcp_rnxt) {
3515 freemsg(mp);
3516 return;
3517 }
3518 }
3519 if (urp != seg_len - 1) {
3520 uint32_t tmp_rnxt;
3521 /*
3522 * There is stuff after the urgent
3523 * byte.
3524 */
3525 mp1 = dupmsg(mp);
3526 if (!mp1) {
3527 /*
3528 * Trim everything beyond the
3529 * urgent byte. The rest will
3530 * come back.
3531 */
3532 (void) adjmsg(mp,
3533 urp + 1 - seg_len);
3534 tcp_input_data(connp,
3535 mp, NULL, ira);
3536 return;
3537 }
3538 (void) adjmsg(mp1, urp + 1 - seg_len);
3539 tmp_rnxt = tcp->tcp_rnxt;
3540 tcp_input_data(connp, mp1, NULL, ira);
3541 /*
3542 * If the data passed back in was not
3543 * processed (ie: bad ACK) sending
3544 * the remainder back in will cause a
3545 * loop. In this case, drop the
3546 * packet and let the sender try
3547 * sending a good packet.
3548 */
3549 if (tmp_rnxt == tcp->tcp_rnxt) {
3550 freemsg(mp);
3551 return;
3552 }
3553 }
3554 tcp_input_data(connp, mp, NULL, ira);
3555 return;
3556 }
3557 /*
3558 * This segment contains only the urgent byte. We
3559 * have to allocate the T_exdata_ind, if we can.
3560 */
3561 if (IPCL_IS_NONSTR(connp)) {
3562 int error;
3563
3564 (*sockupcalls->su_recv)
3565 (connp->conn_upper_handle, mp, seg_len,
3566 MSG_OOB, &error, NULL);
3567 /*
3568 * We should never be in middle of a
3569 * fallback, the squeue guarantees that.
3570 */
3571 ASSERT(error != EOPNOTSUPP);
3572 mp = NULL;
3573 goto update_ack;
3574 } else if (!tcp->tcp_urp_mp) {
3575 struct T_exdata_ind *tei;
3576 mp1 = allocb(sizeof (struct T_exdata_ind),
3577 BPRI_MED);
3578 if (!mp1) {
3579 /*
3580 * Sigh... It'll be back.
3581 * Generate any MSG*MARK message now.
3582 */
3583 freemsg(mp);
3584 seg_len = 0;
3585 if (flags & TH_SEND_URP_MARK) {
3586
3587
3588 ASSERT(tcp->tcp_urp_mark_mp);
3589 tcp->tcp_urp_mark_mp->b_flag &=
3590 ~MSGNOTMARKNEXT;
3591 tcp->tcp_urp_mark_mp->b_flag |=
3592 MSGMARKNEXT;
3593 }
3594 goto ack_check;
3595 }
3596 mp1->b_datap->db_type = M_PROTO;
3597 tei = (struct T_exdata_ind *)mp1->b_rptr;
3598 tei->PRIM_type = T_EXDATA_IND;
3599 tei->MORE_flag = 0;
3600 mp1->b_wptr = (uchar_t *)&tei[1];
3601 tcp->tcp_urp_mp = mp1;
3602 #ifdef DEBUG
3603 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3604 "tcp_rput: allocated exdata_ind %s",
3605 tcp_display(tcp, NULL,
3606 DISP_PORT_ONLY));
3607 #endif /* DEBUG */
3608 /*
3609 * There is no need to send a separate MSG*MARK
3610 * message since the T_EXDATA_IND will be sent
3611 * now.
3612 */
3613 flags &= ~TH_SEND_URP_MARK;
3614 freemsg(tcp->tcp_urp_mark_mp);
3615 tcp->tcp_urp_mark_mp = NULL;
3616 }
3617 /*
3618 * Now we are all set. On the next putnext upstream,
3619 * tcp_urp_mp will be non-NULL and will get prepended
3620 * to what has to be this piece containing the urgent
3621 * byte. If for any reason we abort this segment below,
3622 * if it comes back, we will have this ready, or it
3623 * will get blown off in close.
3624 */
3625 } else if (urp == seg_len) {
3626 /*
3627 * The urgent byte is the next byte after this sequence
3628 * number. If this endpoint is non-STREAMS, then there
3629 * is nothing to do here since the socket has already
3630 * been notified about the urg pointer by the
3631 * su_signal_oob call above.
3632 *
3633 * In case of STREAMS, some more work might be needed.
3634 * If there is data it is marked with MSGMARKNEXT and
3635 * and any tcp_urp_mark_mp is discarded since it is not
3636 * needed. Otherwise, if the code above just allocated
3637 * a zero-length tcp_urp_mark_mp message, that message
3638 * is tagged with MSGMARKNEXT. Sending up these
3639 * MSGMARKNEXT messages makes SIOCATMARK work correctly
3640 * even though the T_EXDATA_IND will not be sent up
3641 * until the urgent byte arrives.
3642 */
3643 if (!IPCL_IS_NONSTR(tcp->tcp_connp)) {
3644 if (seg_len != 0) {
3645 flags |= TH_MARKNEXT_NEEDED;
3646 freemsg(tcp->tcp_urp_mark_mp);
3647 tcp->tcp_urp_mark_mp = NULL;
3648 flags &= ~TH_SEND_URP_MARK;
3649 } else if (tcp->tcp_urp_mark_mp != NULL) {
3650 flags |= TH_SEND_URP_MARK;
3651 tcp->tcp_urp_mark_mp->b_flag &=
3652 ~MSGNOTMARKNEXT;
3653 tcp->tcp_urp_mark_mp->b_flag |=
3654 MSGMARKNEXT;
3655 }
3656 }
3657 #ifdef DEBUG
3658 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3659 "tcp_rput: AT MARK, len %d, flags 0x%x, %s",
3660 seg_len, flags,
3661 tcp_display(tcp, NULL, DISP_PORT_ONLY));
3662 #endif /* DEBUG */
3663 }
3664 #ifdef DEBUG
3665 else {
3666 /* Data left until we hit mark */
3667 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3668 "tcp_rput: URP %d bytes left, %s",
3669 urp - seg_len, tcp_display(tcp, NULL,
3670 DISP_PORT_ONLY));
3671 }
3672 #endif /* DEBUG */
3673 }
3674
3675 process_ack:
3676 if (!(flags & TH_ACK)) {
3677 freemsg(mp);
3678 goto xmit_check;
3679 }
3680 }
3681 bytes_acked = (int)(seg_ack - tcp->tcp_suna);
3682
3683 if (bytes_acked > 0)
3684 tcp->tcp_ip_forward_progress = B_TRUE;
3685 if (tcp->tcp_state == TCPS_SYN_RCVD) {
3686 /*
3687 * tcp_sendmsg() checks tcp_state without entering
3688 * the squeue so tcp_state should be updated before
3689 * sending up a connection confirmation or a new
3690 * connection indication.
3691 */
3692 tcp->tcp_state = TCPS_ESTABLISHED;
3693
3694 /*
3695 * We are seeing the final ack in the three way
3696 * hand shake of a active open'ed connection
3697 * so we must send up a T_CONN_CON
3698 */
3699 if (tcp->tcp_active_open) {
3700 if (!tcp_conn_con(tcp, iphdr, mp, NULL, ira)) {
3701 freemsg(mp);
3702 tcp->tcp_state = TCPS_SYN_RCVD;
3703 return;
3704 }
3705 /*
3706 * Don't fuse the loopback endpoints for
3707 * simultaneous active opens.
3708 */
3709 if (tcp->tcp_loopback) {
3710 TCP_STAT(tcps, tcp_fusion_unfusable);
3711 tcp->tcp_unfusable = B_TRUE;
3712 }
3713 /*
3714 * For simultaneous active open, trace receipt of final
3715 * ACK as tcp:::connect-established.
3716 */
3717 DTRACE_TCP5(connect__established, mblk_t *, NULL,
3718 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3719 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3720 } else if (IPCL_IS_NONSTR(connp)) {
3721 /*
3722 * 3-way handshake has completed, so notify socket
3723 * of the new connection.
3724 *
3725 * We are here means eager is fine but it can
3726 * get a TH_RST at any point between now and till
3727 * accept completes and disappear. We need to
3728 * ensure that reference to eager is valid after
3729 * we get out of eager's perimeter. So we do
3730 * an extra refhold.
3731 */
3732 CONN_INC_REF(connp);
3733
3734 if (!tcp_newconn_notify(tcp, ira)) {
3735 /*
3736 * The state-change probe for SYN_RCVD ->
3737 * ESTABLISHED has not fired yet. We reset
3738 * the state to SYN_RCVD so that future
3739 * state-change probes report correct state
3740 * transistions.
3741 */
3742 tcp->tcp_state = TCPS_SYN_RCVD;
3743 freemsg(mp);
3744 /* notification did not go up, so drop ref */
3745 CONN_DEC_REF(connp);
3746 /* ... and close the eager */
3747 ASSERT(TCP_IS_DETACHED(tcp));
3748 (void) tcp_close_detached(tcp);
3749 return;
3750 }
3751 /*
3752 * tcp_newconn_notify() changes conn_upcalls and
3753 * connp->conn_upper_handle. Fix things now, in case
3754 * there's data attached to this ack.
3755 */
3756 if (connp->conn_upcalls != NULL)
3757 sockupcalls = connp->conn_upcalls;
3758 /*
3759 * For passive open, trace receipt of final ACK as
3760 * tcp:::accept-established.
3761 */
3762 DTRACE_TCP5(accept__established, mlbk_t *, NULL,
3763 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3764 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3765 } else {
3766 /*
3767 * 3-way handshake complete - this is a STREAMS based
3768 * socket, so pass up the T_CONN_IND.
3769 */
3770 tcp_t *listener = tcp->tcp_listener;
3771 mblk_t *mp = tcp->tcp_conn.tcp_eager_conn_ind;
3772
3773 tcp->tcp_tconnind_started = B_TRUE;
3774 tcp->tcp_conn.tcp_eager_conn_ind = NULL;
3775 ASSERT(mp != NULL);
3776 /*
3777 * We are here means eager is fine but it can
3778 * get a TH_RST at any point between now and till
3779 * accept completes and disappear. We need to
3780 * ensure that reference to eager is valid after
3781 * we get out of eager's perimeter. So we do
3782 * an extra refhold.
3783 */
3784 CONN_INC_REF(connp);
3785
3786 /*
3787 * The listener also exists because of the refhold
3788 * done in tcp_input_listener. Its possible that it
3789 * might have closed. We will check that once we
3790 * get inside listeners context.
3791 */
3792 CONN_INC_REF(listener->tcp_connp);
3793 if (listener->tcp_connp->conn_sqp ==
3794 connp->conn_sqp) {
3795 /*
3796 * We optimize by not calling an SQUEUE_ENTER
3797 * on the listener since we know that the
3798 * listener and eager squeues are the same.
3799 * We are able to make this check safely only
3800 * because neither the eager nor the listener
3801 * can change its squeue. Only an active connect
3802 * can change its squeue
3803 */
3804 tcp_send_conn_ind(listener->tcp_connp, mp,
3805 listener->tcp_connp->conn_sqp);
3806 CONN_DEC_REF(listener->tcp_connp);
3807 } else if (!tcp->tcp_loopback) {
3808 SQUEUE_ENTER_ONE(listener->tcp_connp->conn_sqp,
3809 mp, tcp_send_conn_ind,
3810 listener->tcp_connp, NULL, SQ_FILL,
3811 SQTAG_TCP_CONN_IND);
3812 } else {
3813 SQUEUE_ENTER_ONE(listener->tcp_connp->conn_sqp,
3814 mp, tcp_send_conn_ind,
3815 listener->tcp_connp, NULL, SQ_NODRAIN,
3816 SQTAG_TCP_CONN_IND);
3817 }
3818 /*
3819 * For passive open, trace receipt of final ACK as
3820 * tcp:::accept-established.
3821 */
3822 DTRACE_TCP5(accept__established, mlbk_t *, NULL,
3823 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3824 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3825 }
3826 TCPS_CONN_INC(tcps);
3827
3828 tcp->tcp_suna = tcp->tcp_iss + 1; /* One for the SYN */
3829 bytes_acked--;
3830 /* SYN was acked - making progress */
3831 tcp->tcp_ip_forward_progress = B_TRUE;
3832
3833 /*
3834 * If SYN was retransmitted, need to reset all
3835 * retransmission info as this segment will be
3836 * treated as a dup ACK.
3837 */
3838 if (tcp->tcp_rexmit) {
3839 tcp->tcp_rexmit = B_FALSE;
3840 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
3841 tcp->tcp_rexmit_max = tcp->tcp_snxt;
3842 tcp->tcp_ms_we_have_waited = 0;
3843 tcp->tcp_cwnd = mss;
3844 }
3845
3846 /*
3847 * We set the send window to zero here.
3848 * This is needed if there is data to be
3849 * processed already on the queue.
3850 * Later (at swnd_update label), the
3851 * "new_swnd > tcp_swnd" condition is satisfied
3852 * the XMIT_NEEDED flag is set in the current
3853 * (SYN_RCVD) state. This ensures tcp_wput_data() is
3854 * called if there is already data on queue in
3855 * this state.
3856 */
3857 tcp->tcp_swnd = 0;
3858
3859 if (new_swnd > tcp->tcp_max_swnd)
3860 tcp->tcp_max_swnd = new_swnd;
3861 tcp->tcp_swl1 = seg_seq;
3862 tcp->tcp_swl2 = seg_ack;
3863 tcp->tcp_valid_bits &= ~TCP_ISS_VALID;
3864
3865 /* Trace change from SYN_RCVD -> ESTABLISHED here */
3866 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
3867 connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
3868 int32_t, TCPS_SYN_RCVD);
3869
3870 /* Fuse when both sides are in ESTABLISHED state */
3871 if (tcp->tcp_loopback && do_tcp_fusion)
3872 tcp_fuse(tcp, iphdr, tcpha);
3873
3874 }
3875 /* This code follows 4.4BSD-Lite2 mostly. */
3876 if (bytes_acked < 0)
3877 goto est;
3878
3879 /*
3880 * If TCP is ECN capable and the congestion experience bit is
3881 * set, reduce tcp_cwnd and tcp_ssthresh. But this should only be
3882 * done once per window (or more loosely, per RTT).
3883 */
3884 if (tcp->tcp_cwr && SEQ_GT(seg_ack, tcp->tcp_cwr_snd_max))
3885 tcp->tcp_cwr = B_FALSE;
3886 if (tcp->tcp_ecn_ok && (flags & TH_ECE)) {
3887 if (!tcp->tcp_cwr) {
3888 npkt = ((tcp->tcp_snxt - tcp->tcp_suna) >> 1) / mss;
3889 tcp->tcp_cwnd_ssthresh = MAX(npkt, 2) * mss;
3890 tcp->tcp_cwnd = npkt * mss;
3891 /*
3892 * If the cwnd is 0, use the timer to clock out
3893 * new segments. This is required by the ECN spec.
3894 */
3895 if (npkt == 0) {
3896 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
3897 /*
3898 * This makes sure that when the ACK comes
3899 * back, we will increase tcp_cwnd by 1 MSS.
3900 */
3901 tcp->tcp_cwnd_cnt = 0;
3902 }
3903 tcp->tcp_cwr = B_TRUE;
3904 /*
3905 * This marks the end of the current window of in
3906 * flight data. That is why we don't use
3907 * tcp_suna + tcp_swnd. Only data in flight can
3908 * provide ECN info.
3909 */
3910 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
3911 tcp->tcp_ecn_cwr_sent = B_FALSE;
3912 }
3913 }
3914
3915 mp1 = tcp->tcp_xmit_head;
3916 if (bytes_acked == 0) {
3917 if (!ofo_seg && seg_len == 0 && new_swnd == tcp->tcp_swnd) {
3918 int dupack_cnt;
3919
3920 TCPS_BUMP_MIB(tcps, tcpInDupAck);
3921 /*
3922 * Fast retransmit. When we have seen exactly three
3923 * identical ACKs while we have unacked data
3924 * outstanding we take it as a hint that our peer
3925 * dropped something.
3926 *
3927 * If TCP is retransmitting, don't do fast retransmit.
3928 */
3929 if (mp1 && tcp->tcp_suna != tcp->tcp_snxt &&
3930 ! tcp->tcp_rexmit) {
3931 /* Do Limited Transmit */
3932 if ((dupack_cnt = ++tcp->tcp_dupack_cnt) <
3933 tcps->tcps_dupack_fast_retransmit) {
3934 /*
3935 * RFC 3042
3936 *
3937 * What we need to do is temporarily
3938 * increase tcp_cwnd so that new
3939 * data can be sent if it is allowed
3940 * by the receive window (tcp_rwnd).
3941 * tcp_wput_data() will take care of
3942 * the rest.
3943 *
3944 * If the connection is SACK capable,
3945 * only do limited xmit when there
3946 * is SACK info.
3947 *
3948 * Note how tcp_cwnd is incremented.
3949 * The first dup ACK will increase
3950 * it by 1 MSS. The second dup ACK
3951 * will increase it by 2 MSS. This
3952 * means that only 1 new segment will
3953 * be sent for each dup ACK.
3954 */
3955 if (tcp->tcp_unsent > 0 &&
3956 (!tcp->tcp_snd_sack_ok ||
3957 (tcp->tcp_snd_sack_ok &&
3958 tcp->tcp_notsack_list != NULL))) {
3959 tcp->tcp_cwnd += mss <<
3960 (tcp->tcp_dupack_cnt - 1);
3961 flags |= TH_LIMIT_XMIT;
3962 }
3963 } else if (dupack_cnt ==
3964 tcps->tcps_dupack_fast_retransmit) {
3965
3966 /*
3967 * If we have reduced tcp_ssthresh
3968 * because of ECN, do not reduce it again
3969 * unless it is already one window of data
3970 * away. After one window of data, tcp_cwr
3971 * should then be cleared. Note that
3972 * for non ECN capable connection, tcp_cwr
3973 * should always be false.
3974 *
3975 * Adjust cwnd since the duplicate
3976 * ack indicates that a packet was
3977 * dropped (due to congestion.)
3978 */
3979 if (!tcp->tcp_cwr) {
3980 npkt = ((tcp->tcp_snxt -
3981 tcp->tcp_suna) >> 1) / mss;
3982 tcp->tcp_cwnd_ssthresh = MAX(npkt, 2) *
3983 mss;
3984 tcp->tcp_cwnd = (npkt +
3985 tcp->tcp_dupack_cnt) * mss;
3986 }
3987 if (tcp->tcp_ecn_ok) {
3988 tcp->tcp_cwr = B_TRUE;
3989 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
3990 tcp->tcp_ecn_cwr_sent = B_FALSE;
3991 }
3992
3993 /*
3994 * We do Hoe's algorithm. Refer to her
3995 * paper "Improving the Start-up Behavior
3996 * of a Congestion Control Scheme for TCP,"
3997 * appeared in SIGCOMM'96.
3998 *
3999 * Save highest seq no we have sent so far.
4000 * Be careful about the invisible FIN byte.
4001 */
4002 if ((tcp->tcp_valid_bits & TCP_FSS_VALID) &&
4003 (tcp->tcp_unsent == 0)) {
4004 tcp->tcp_rexmit_max = tcp->tcp_fss;
4005 } else {
4006 tcp->tcp_rexmit_max = tcp->tcp_snxt;
4007 }
4008
4009 /*
4010 * For SACK:
4011 * Calculate tcp_pipe, which is the
4012 * estimated number of bytes in
4013 * network.
4014 *
4015 * tcp_fack is the highest sack'ed seq num
4016 * TCP has received.
4017 *
4018 * tcp_pipe is explained in the above quoted
4019 * Fall and Floyd's paper. tcp_fack is
4020 * explained in Mathis and Mahdavi's
4021 * "Forward Acknowledgment: Refining TCP
4022 * Congestion Control" in SIGCOMM '96.
4023 */
4024 if (tcp->tcp_snd_sack_ok) {
4025 if (tcp->tcp_notsack_list != NULL) {
4026 tcp->tcp_pipe = tcp->tcp_snxt -
4027 tcp->tcp_fack;
4028 tcp->tcp_sack_snxt = seg_ack;
4029 flags |= TH_NEED_SACK_REXMIT;
4030 } else {
4031 /*
4032 * Always initialize tcp_pipe
4033 * even though we don't have
4034 * any SACK info. If later
4035 * we get SACK info and
4036 * tcp_pipe is not initialized,
4037 * funny things will happen.
4038 */
4039 tcp->tcp_pipe =
4040 tcp->tcp_cwnd_ssthresh;
4041 }
4042 } else {
4043 flags |= TH_REXMIT_NEEDED;
4044 } /* tcp_snd_sack_ok */
4045
4046 } else {
4047 /*
4048 * Here we perform congestion
4049 * avoidance, but NOT slow start.
4050 * This is known as the Fast
4051 * Recovery Algorithm.
4052 */
4053 if (tcp->tcp_snd_sack_ok &&
4054 tcp->tcp_notsack_list != NULL) {
4055 flags |= TH_NEED_SACK_REXMIT;
4056 tcp->tcp_pipe -= mss;
4057 if (tcp->tcp_pipe < 0)
4058 tcp->tcp_pipe = 0;
4059 } else {
4060 /*
4061 * We know that one more packet has
4062 * left the pipe thus we can update
4063 * cwnd.
4064 */
4065 cwnd = tcp->tcp_cwnd + mss;
4066 if (cwnd > tcp->tcp_cwnd_max)
4067 cwnd = tcp->tcp_cwnd_max;
4068 tcp->tcp_cwnd = cwnd;
4069 if (tcp->tcp_unsent > 0)
4070 flags |= TH_XMIT_NEEDED;
4071 }
4072 }
4073 }
4074 } else if (tcp->tcp_zero_win_probe) {
4075 /*
4076 * If the window has opened, need to arrange
4077 * to send additional data.
4078 */
4079 if (new_swnd != 0) {
4080 /* tcp_suna != tcp_snxt */
4081 /* Packet contains a window update */
4082 TCPS_BUMP_MIB(tcps, tcpInWinUpdate);
4083 tcp->tcp_zero_win_probe = 0;
4084 tcp->tcp_timer_backoff = 0;
4085 tcp->tcp_ms_we_have_waited = 0;
4086
4087 /*
4088 * Transmit starting with tcp_suna since
4089 * the one byte probe is not ack'ed.
4090 * If TCP has sent more than one identical
4091 * probe, tcp_rexmit will be set. That means
4092 * tcp_ss_rexmit() will send out the one
4093 * byte along with new data. Otherwise,
4094 * fake the retransmission.
4095 */
4096 flags |= TH_XMIT_NEEDED;
4097 if (!tcp->tcp_rexmit) {
4098 tcp->tcp_rexmit = B_TRUE;
4099 tcp->tcp_dupack_cnt = 0;
4100 tcp->tcp_rexmit_nxt = tcp->tcp_suna;
4101 tcp->tcp_rexmit_max = tcp->tcp_suna + 1;
4102 }
4103 }
4104 }
4105 goto swnd_update;
4106 }
4107
4108 /*
4109 * Check for "acceptability" of ACK value per RFC 793, pages 72 - 73.
4110 * If the ACK value acks something that we have not yet sent, it might
4111 * be an old duplicate segment. Send an ACK to re-synchronize the
4112 * other side.
4113 * Note: reset in response to unacceptable ACK in SYN_RECEIVE
4114 * state is handled above, so we can always just drop the segment and
4115 * send an ACK here.
4116 *
4117 * In the case where the peer shrinks the window, we see the new window
4118 * update, but all the data sent previously is queued up by the peer.
4119 * To account for this, in tcp_process_shrunk_swnd(), the sequence
4120 * number, which was already sent, and within window, is recorded.
4121 * tcp_snxt is then updated.
4122 *
4123 * If the window has previously shrunk, and an ACK for data not yet
4124 * sent, according to tcp_snxt is recieved, it may still be valid. If
4125 * the ACK is for data within the window at the time the window was
4126 * shrunk, then the ACK is acceptable. In this case tcp_snxt is set to
4127 * the sequence number ACK'ed.
4128 *
4129 * If the ACK covers all the data sent at the time the window was
4130 * shrunk, we can now set tcp_is_wnd_shrnk to B_FALSE.
4131 *
4132 * Should we send ACKs in response to ACK only segments?
4133 */
4134
4135 if (SEQ_GT(seg_ack, tcp->tcp_snxt)) {
4136 if ((tcp->tcp_is_wnd_shrnk) &&
4137 (SEQ_LEQ(seg_ack, tcp->tcp_snxt_shrunk))) {
4138 uint32_t data_acked_ahead_snxt;
4139
4140 data_acked_ahead_snxt = seg_ack - tcp->tcp_snxt;
4141 tcp_update_xmit_tail(tcp, seg_ack);
4142 tcp->tcp_unsent -= data_acked_ahead_snxt;
4143 } else {
4144 TCPS_BUMP_MIB(tcps, tcpInAckUnsent);
4145 /* drop the received segment */
4146 freemsg(mp);
4147
4148 /*
4149 * Send back an ACK. If tcp_drop_ack_unsent_cnt is
4150 * greater than 0, check if the number of such
4151 * bogus ACks is greater than that count. If yes,
4152 * don't send back any ACK. This prevents TCP from
4153 * getting into an ACK storm if somehow an attacker
4154 * successfully spoofs an acceptable segment to our
4155 * peer. If this continues (count > 2 X threshold),
4156 * we should abort this connection.
4157 */
4158 if (tcp_drop_ack_unsent_cnt > 0 &&
4159 ++tcp->tcp_in_ack_unsent >
4160 tcp_drop_ack_unsent_cnt) {
4161 TCP_STAT(tcps, tcp_in_ack_unsent_drop);
4162 if (tcp->tcp_in_ack_unsent > 2 *
4163 tcp_drop_ack_unsent_cnt) {
4164 (void) tcp_clean_death(tcp, EPROTO);
4165 }
4166 return;
4167 }
4168 mp = tcp_ack_mp(tcp);
4169 if (mp != NULL) {
4170 BUMP_LOCAL(tcp->tcp_obsegs);
4171 TCPS_BUMP_MIB(tcps, tcpOutAck);
4172 tcp_send_data(tcp, mp);
4173 }
4174 return;
4175 }
4176 } else if (tcp->tcp_is_wnd_shrnk && SEQ_GEQ(seg_ack,
4177 tcp->tcp_snxt_shrunk)) {
4178 tcp->tcp_is_wnd_shrnk = B_FALSE;
4179 }
4180
4181 /*
4182 * TCP gets a new ACK, update the notsack'ed list to delete those
4183 * blocks that are covered by this ACK.
4184 */
4185 if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) {
4186 tcp_notsack_remove(&(tcp->tcp_notsack_list), seg_ack,
4187 &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list));
4188 }
4189
4190 /*
4191 * If we got an ACK after fast retransmit, check to see
4192 * if it is a partial ACK. If it is not and the congestion
4193 * window was inflated to account for the other side's
4194 * cached packets, retract it. If it is, do Hoe's algorithm.
4195 */
4196 if (tcp->tcp_dupack_cnt >= tcps->tcps_dupack_fast_retransmit) {
4197 ASSERT(tcp->tcp_rexmit == B_FALSE);
4198 if (SEQ_GEQ(seg_ack, tcp->tcp_rexmit_max)) {
4199 tcp->tcp_dupack_cnt = 0;
4200 /*
4201 * Restore the orig tcp_cwnd_ssthresh after
4202 * fast retransmit phase.
4203 */
4204 if (tcp->tcp_cwnd > tcp->tcp_cwnd_ssthresh) {
4205 tcp->tcp_cwnd = tcp->tcp_cwnd_ssthresh;
4206 }
4207 tcp->tcp_rexmit_max = seg_ack;
4208 tcp->tcp_cwnd_cnt = 0;
4209
4210 /*
4211 * Remove all notsack info to avoid confusion with
4212 * the next fast retrasnmit/recovery phase.
4213 */
4214 if (tcp->tcp_snd_sack_ok) {
4215 TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list,
4216 tcp);
4217 }
4218 } else {
4219 if (tcp->tcp_snd_sack_ok &&
4220 tcp->tcp_notsack_list != NULL) {
4221 flags |= TH_NEED_SACK_REXMIT;
4222 tcp->tcp_pipe -= mss;
4223 if (tcp->tcp_pipe < 0)
4224 tcp->tcp_pipe = 0;
4225 } else {
4226 /*
4227 * Hoe's algorithm:
4228 *
4229 * Retransmit the unack'ed segment and
4230 * restart fast recovery. Note that we
4231 * need to scale back tcp_cwnd to the
4232 * original value when we started fast
4233 * recovery. This is to prevent overly
4234 * aggressive behaviour in sending new
4235 * segments.
4236 */
4237 tcp->tcp_cwnd = tcp->tcp_cwnd_ssthresh +
4238 tcps->tcps_dupack_fast_retransmit * mss;
4239 tcp->tcp_cwnd_cnt = tcp->tcp_cwnd;
4240 flags |= TH_REXMIT_NEEDED;
4241 }
4242 }
4243 } else {
4244 tcp->tcp_dupack_cnt = 0;
4245 if (tcp->tcp_rexmit) {
4246 /*
4247 * TCP is retranmitting. If the ACK ack's all
4248 * outstanding data, update tcp_rexmit_max and
4249 * tcp_rexmit_nxt. Otherwise, update tcp_rexmit_nxt
4250 * to the correct value.
4251 *
4252 * Note that SEQ_LEQ() is used. This is to avoid
4253 * unnecessary fast retransmit caused by dup ACKs
4254 * received when TCP does slow start retransmission
4255 * after a time out. During this phase, TCP may
4256 * send out segments which are already received.
4257 * This causes dup ACKs to be sent back.
4258 */
4259 if (SEQ_LEQ(seg_ack, tcp->tcp_rexmit_max)) {
4260 if (SEQ_GT(seg_ack, tcp->tcp_rexmit_nxt)) {
4261 tcp->tcp_rexmit_nxt = seg_ack;
4262 }
4263 if (seg_ack != tcp->tcp_rexmit_max) {
4264 flags |= TH_XMIT_NEEDED;
4265 }
4266 } else {
4267 tcp->tcp_rexmit = B_FALSE;
4268 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
4269 }
4270 tcp->tcp_ms_we_have_waited = 0;
4271 }
4272 }
4273
4274 TCPS_BUMP_MIB(tcps, tcpInAckSegs);
4275 TCPS_UPDATE_MIB(tcps, tcpInAckBytes, bytes_acked);
4276 tcp->tcp_suna = seg_ack;
4277 if (tcp->tcp_zero_win_probe != 0) {
4278 tcp->tcp_zero_win_probe = 0;
4279 tcp->tcp_timer_backoff = 0;
4280 }
4281
4282 /*
4283 * If tcp_xmit_head is NULL, then it must be the FIN being ack'ed.
4284 * Note that it cannot be the SYN being ack'ed. The code flow
4285 * will not reach here.
4286 */
4287 if (mp1 == NULL) {
4288 goto fin_acked;
4289 }
4290
4291 /*
4292 * Update the congestion window.
4293 *
4294 * If TCP is not ECN capable or TCP is ECN capable but the
4295 * congestion experience bit is not set, increase the tcp_cwnd as
4296 * usual.
4297 */
4298 if (!tcp->tcp_ecn_ok || !(flags & TH_ECE)) {
4299 cwnd = tcp->tcp_cwnd;
4300 add = mss;
4301
4302 if (cwnd >= tcp->tcp_cwnd_ssthresh) {
4303 /*
4304 * This is to prevent an increase of less than 1 MSS of
4305 * tcp_cwnd. With partial increase, tcp_wput_data()
4306 * may send out tinygrams in order to preserve mblk
4307 * boundaries.
4308 *
4309 * By initializing tcp_cwnd_cnt to new tcp_cwnd and
4310 * decrementing it by 1 MSS for every ACKs, tcp_cwnd is
4311 * increased by 1 MSS for every RTTs.
4312 */
4313 if (tcp->tcp_cwnd_cnt <= 0) {
4314 tcp->tcp_cwnd_cnt = cwnd + add;
4315 } else {
4316 tcp->tcp_cwnd_cnt -= add;
4317 add = 0;
4318 }
4319 }
4320 tcp->tcp_cwnd = MIN(cwnd + add, tcp->tcp_cwnd_max);
4321 }
4322
4323 /* See if the latest urgent data has been acknowledged */
4324 if ((tcp->tcp_valid_bits & TCP_URG_VALID) &&
4325 SEQ_GT(seg_ack, tcp->tcp_urg))
4326 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
4327
4328 /* Can we update the RTT estimates? */
4329 if (tcp->tcp_snd_ts_ok) {
4330 /* Ignore zero timestamp echo-reply. */
4331 if (tcpopt.tcp_opt_ts_ecr != 0) {
4332 tcp_set_rto(tcp, (int32_t)LBOLT_FASTPATH -
4333 (int32_t)tcpopt.tcp_opt_ts_ecr);
4334 }
4335
4336 /* If needed, restart the timer. */
4337 if (tcp->tcp_set_timer == 1) {
4338 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
4339 tcp->tcp_set_timer = 0;
4340 }
4341 /*
4342 * Update tcp_csuna in case the other side stops sending
4343 * us timestamps.
4344 */
4345 tcp->tcp_csuna = tcp->tcp_snxt;
4346 } else if (SEQ_GT(seg_ack, tcp->tcp_csuna)) {
4347 /*
4348 * An ACK sequence we haven't seen before, so get the RTT
4349 * and update the RTO. But first check if the timestamp is
4350 * valid to use.
4351 */
4352 if ((mp1->b_next != NULL) &&
4353 SEQ_GT(seg_ack, (uint32_t)(uintptr_t)(mp1->b_next)))
4354 tcp_set_rto(tcp, (int32_t)LBOLT_FASTPATH -
4355 (int32_t)(intptr_t)mp1->b_prev);
4356 else
4357 TCPS_BUMP_MIB(tcps, tcpRttNoUpdate);
4358
4359 /* Remeber the last sequence to be ACKed */
4360 tcp->tcp_csuna = seg_ack;
4361 if (tcp->tcp_set_timer == 1) {
4362 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
4363 tcp->tcp_set_timer = 0;
4364 }
4365 } else {
4366 TCPS_BUMP_MIB(tcps, tcpRttNoUpdate);
4367 }
4368
4369 /* Eat acknowledged bytes off the xmit queue. */
4370 for (;;) {
4371 mblk_t *mp2;
4372 uchar_t *wptr;
4373
4374 wptr = mp1->b_wptr;
4375 ASSERT((uintptr_t)(wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX);
4376 bytes_acked -= (int)(wptr - mp1->b_rptr);
4377 if (bytes_acked < 0) {
4378 mp1->b_rptr = wptr + bytes_acked;
4379 /*
4380 * Set a new timestamp if all the bytes timed by the
4381 * old timestamp have been ack'ed.
4382 */
4383 if (SEQ_GT(seg_ack,
4384 (uint32_t)(uintptr_t)(mp1->b_next))) {
4385 mp1->b_prev =
4386 (mblk_t *)(uintptr_t)LBOLT_FASTPATH;
4387 mp1->b_next = NULL;
4388 }
4389 break;
4390 }
4391 mp1->b_next = NULL;
4392 mp1->b_prev = NULL;
4393 mp2 = mp1;
4394 mp1 = mp1->b_cont;
4395
4396 /*
4397 * This notification is required for some zero-copy
4398 * clients to maintain a copy semantic. After the data
4399 * is ack'ed, client is safe to modify or reuse the buffer.
4400 */
4401 if (tcp->tcp_snd_zcopy_aware &&
4402 (mp2->b_datap->db_struioflag & STRUIO_ZCNOTIFY))
4403 tcp_zcopy_notify(tcp);
4404 freeb(mp2);
4405 if (bytes_acked == 0) {
4406 if (mp1 == NULL) {
4407 /* Everything is ack'ed, clear the tail. */
4408 tcp->tcp_xmit_tail = NULL;
4409 /*
4410 * Cancel the timer unless we are still
4411 * waiting for an ACK for the FIN packet.
4412 */
4413 if (tcp->tcp_timer_tid != 0 &&
4414 tcp->tcp_snxt == tcp->tcp_suna) {
4415 (void) TCP_TIMER_CANCEL(tcp,
4416 tcp->tcp_timer_tid);
4417 tcp->tcp_timer_tid = 0;
4418 }
4419 goto pre_swnd_update;
4420 }
4421 if (mp2 != tcp->tcp_xmit_tail)
4422 break;
4423 tcp->tcp_xmit_tail = mp1;
4424 ASSERT((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <=
4425 (uintptr_t)INT_MAX);
4426 tcp->tcp_xmit_tail_unsent = (int)(mp1->b_wptr -
4427 mp1->b_rptr);
4428 break;
4429 }
4430 if (mp1 == NULL) {
4431 /*
4432 * More was acked but there is nothing more
4433 * outstanding. This means that the FIN was
4434 * just acked or that we're talking to a clown.
4435 */
4436 fin_acked:
4437 ASSERT(tcp->tcp_fin_sent);
4438 tcp->tcp_xmit_tail = NULL;
4439 if (tcp->tcp_fin_sent) {
4440 /* FIN was acked - making progress */
4441 if (!tcp->tcp_fin_acked)
4442 tcp->tcp_ip_forward_progress = B_TRUE;
4443 tcp->tcp_fin_acked = B_TRUE;
4444 if (tcp->tcp_linger_tid != 0 &&
4445 TCP_TIMER_CANCEL(tcp,
4446 tcp->tcp_linger_tid) >= 0) {
4447 tcp_stop_lingering(tcp);
4448 freemsg(mp);
4449 mp = NULL;
4450 }
4451 } else {
4452 /*
4453 * We should never get here because
4454 * we have already checked that the
4455 * number of bytes ack'ed should be
4456 * smaller than or equal to what we
4457 * have sent so far (it is the
4458 * acceptability check of the ACK).
4459 * We can only get here if the send
4460 * queue is corrupted.
4461 *
4462 * Terminate the connection and
4463 * panic the system. It is better
4464 * for us to panic instead of
4465 * continuing to avoid other disaster.
4466 */
4467 tcp_xmit_ctl(NULL, tcp, tcp->tcp_snxt,
4468 tcp->tcp_rnxt, TH_RST|TH_ACK);
4469 panic("Memory corruption "
4470 "detected for connection %s.",
4471 tcp_display(tcp, NULL,
4472 DISP_ADDR_AND_PORT));
4473 /*NOTREACHED*/
4474 }
4475 goto pre_swnd_update;
4476 }
4477 ASSERT(mp2 != tcp->tcp_xmit_tail);
4478 }
4479 if (tcp->tcp_unsent) {
4480 flags |= TH_XMIT_NEEDED;
4481 }
4482 pre_swnd_update:
4483 tcp->tcp_xmit_head = mp1;
4484 swnd_update:
4485 /*
4486 * The following check is different from most other implementations.
4487 * For bi-directional transfer, when segments are dropped, the
4488 * "normal" check will not accept a window update in those
4489 * retransmitted segemnts. Failing to do that, TCP may send out
4490 * segments which are outside receiver's window. As TCP accepts
4491 * the ack in those retransmitted segments, if the window update in
4492 * the same segment is not accepted, TCP will incorrectly calculates
4493 * that it can send more segments. This can create a deadlock
4494 * with the receiver if its window becomes zero.
4495 */
4496 if (SEQ_LT(tcp->tcp_swl2, seg_ack) ||
4497 SEQ_LT(tcp->tcp_swl1, seg_seq) ||
4498 (tcp->tcp_swl1 == seg_seq && new_swnd > tcp->tcp_swnd)) {
4499 /*
4500 * The criteria for update is:
4501 *
4502 * 1. the segment acknowledges some data. Or
4503 * 2. the segment is new, i.e. it has a higher seq num. Or
4504 * 3. the segment is not old and the advertised window is
4505 * larger than the previous advertised window.
4506 */
4507 if (tcp->tcp_unsent && new_swnd > tcp->tcp_swnd)
4508 flags |= TH_XMIT_NEEDED;
4509 tcp->tcp_swnd = new_swnd;
4510 if (new_swnd > tcp->tcp_max_swnd)
4511 tcp->tcp_max_swnd = new_swnd;
4512 tcp->tcp_swl1 = seg_seq;
4513 tcp->tcp_swl2 = seg_ack;
4514 }
4515 est:
4516 if (tcp->tcp_state > TCPS_ESTABLISHED) {
4517
4518 switch (tcp->tcp_state) {
4519 case TCPS_FIN_WAIT_1:
4520 if (tcp->tcp_fin_acked) {
4521 tcp->tcp_state = TCPS_FIN_WAIT_2;
4522 DTRACE_TCP6(state__change, void, NULL,
4523 ip_xmit_attr_t *, connp->conn_ixa,
4524 void, NULL, tcp_t *, tcp, void, NULL,
4525 int32_t, TCPS_FIN_WAIT_1);
4526 /*
4527 * We implement the non-standard BSD/SunOS
4528 * FIN_WAIT_2 flushing algorithm.
4529 * If there is no user attached to this
4530 * TCP endpoint, then this TCP struct
4531 * could hang around forever in FIN_WAIT_2
4532 * state if the peer forgets to send us
4533 * a FIN. To prevent this, we wait only
4534 * 2*MSL (a convenient time value) for
4535 * the FIN to arrive. If it doesn't show up,
4536 * we flush the TCP endpoint. This algorithm,
4537 * though a violation of RFC-793, has worked
4538 * for over 10 years in BSD systems.
4539 * Note: SunOS 4.x waits 675 seconds before
4540 * flushing the FIN_WAIT_2 connection.
4541 */
4542 TCP_TIMER_RESTART(tcp,
4543 tcp->tcp_fin_wait_2_flush_interval);
4544 }
4545 break;
4546 case TCPS_FIN_WAIT_2:
4547 break; /* Shutdown hook? */
4548 case TCPS_LAST_ACK:
4549 freemsg(mp);
4550 if (tcp->tcp_fin_acked) {
4551 (void) tcp_clean_death(tcp, 0);
4552 return;
4553 }
4554 goto xmit_check;
4555 case TCPS_CLOSING:
4556 if (tcp->tcp_fin_acked) {
4557 SET_TIME_WAIT(tcps, tcp, connp);
4558 DTRACE_TCP6(state__change, void, NULL,
4559 ip_xmit_attr_t *, connp->conn_ixa, void,
4560 NULL, tcp_t *, tcp, void, NULL, int32_t,
4561 TCPS_CLOSING);
4562 }
4563 /*FALLTHRU*/
4564 case TCPS_CLOSE_WAIT:
4565 freemsg(mp);
4566 goto xmit_check;
4567 default:
4568 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
4569 break;
4570 }
4571 }
4572 if (flags & TH_FIN) {
4573 /* Make sure we ack the fin */
4574 flags |= TH_ACK_NEEDED;
4575 if (!tcp->tcp_fin_rcvd) {
4576 tcp->tcp_fin_rcvd = B_TRUE;
4577 tcp->tcp_rnxt++;
4578 tcpha = tcp->tcp_tcpha;
4579 tcpha->tha_ack = htonl(tcp->tcp_rnxt);
4580
4581 /*
4582 * Generate the ordrel_ind at the end unless the
4583 * conn is detached or it is a STREAMS based eager.
4584 * In the eager case we defer the notification until
4585 * tcp_accept_finish has run.
4586 */
4587 if (!TCP_IS_DETACHED(tcp) && (IPCL_IS_NONSTR(connp) ||
4588 (tcp->tcp_listener == NULL &&
4589 !tcp->tcp_hard_binding)))
4590 flags |= TH_ORDREL_NEEDED;
4591 switch (tcp->tcp_state) {
4592 case TCPS_SYN_RCVD:
4593 tcp->tcp_state = TCPS_CLOSE_WAIT;
4594 DTRACE_TCP6(state__change, void, NULL,
4595 ip_xmit_attr_t *, connp->conn_ixa,
4596 void, NULL, tcp_t *, tcp, void, NULL,
4597 int32_t, TCPS_SYN_RCVD);
4598 /* Keepalive? */
4599 break;
4600 case TCPS_ESTABLISHED:
4601 tcp->tcp_state = TCPS_CLOSE_WAIT;
4602 DTRACE_TCP6(state__change, void, NULL,
4603 ip_xmit_attr_t *, connp->conn_ixa,
4604 void, NULL, tcp_t *, tcp, void, NULL,
4605 int32_t, TCPS_ESTABLISHED);
4606 /* Keepalive? */
4607 break;
4608 case TCPS_FIN_WAIT_1:
4609 if (!tcp->tcp_fin_acked) {
4610 tcp->tcp_state = TCPS_CLOSING;
4611 DTRACE_TCP6(state__change, void, NULL,
4612 ip_xmit_attr_t *, connp->conn_ixa,
4613 void, NULL, tcp_t *, tcp, void,
4614 NULL, int32_t, TCPS_FIN_WAIT_1);
4615 break;
4616 }
4617 /* FALLTHRU */
4618 case TCPS_FIN_WAIT_2:
4619 SET_TIME_WAIT(tcps, tcp, connp);
4620 DTRACE_TCP6(state__change, void, NULL,
4621 ip_xmit_attr_t *, connp->conn_ixa, void,
4622 NULL, tcp_t *, tcp, void, NULL, int32_t,
4623 TCPS_FIN_WAIT_2);
4624 if (seg_len) {
4625 /*
4626 * implies data piggybacked on FIN.
4627 * break to handle data.
4628 */
4629 break;
4630 }
4631 freemsg(mp);
4632 goto ack_check;
4633 }
4634 }
4635 }
4636 if (mp == NULL)
4637 goto xmit_check;
4638 if (seg_len == 0) {
4639 freemsg(mp);
4640 goto xmit_check;
4641 }
4642 if (mp->b_rptr == mp->b_wptr) {
4643 /*
4644 * The header has been consumed, so we remove the
4645 * zero-length mblk here.
4646 */
4647 mp1 = mp;
4648 mp = mp->b_cont;
4649 freeb(mp1);
4650 }
4651 update_ack:
4652 tcpha = tcp->tcp_tcpha;
4653 tcp->tcp_rack_cnt++;
4654 {
4655 uint32_t cur_max;
4656
4657 cur_max = tcp->tcp_rack_cur_max;
4658 if (tcp->tcp_rack_cnt >= cur_max) {
4659 /*
4660 * We have more unacked data than we should - send
4661 * an ACK now.
4662 */
4663 flags |= TH_ACK_NEEDED;
4664 cur_max++;
4665 if (cur_max > tcp->tcp_rack_abs_max)
4666 tcp->tcp_rack_cur_max = tcp->tcp_rack_abs_max;
4667 else
4668 tcp->tcp_rack_cur_max = cur_max;
4669 } else if (TCP_IS_DETACHED(tcp)) {
4670 /* We don't have an ACK timer for detached TCP. */
4671 flags |= TH_ACK_NEEDED;
4672 } else if (seg_len < mss) {
4673 /*
4674 * If we get a segment that is less than an mss, and we
4675 * already have unacknowledged data, and the amount
4676 * unacknowledged is not a multiple of mss, then we
4677 * better generate an ACK now. Otherwise, this may be
4678 * the tail piece of a transaction, and we would rather
4679 * wait for the response.
4680 */
4681 uint32_t udif;
4682 ASSERT((uintptr_t)(tcp->tcp_rnxt - tcp->tcp_rack) <=
4683 (uintptr_t)INT_MAX);
4684 udif = (int)(tcp->tcp_rnxt - tcp->tcp_rack);
4685 if (udif && (udif % mss))
4686 flags |= TH_ACK_NEEDED;
4687 else
4688 flags |= TH_ACK_TIMER_NEEDED;
4689 } else {
4690 /* Start delayed ack timer */
4691 flags |= TH_ACK_TIMER_NEEDED;
4692 }
4693 }
4694 tcp->tcp_rnxt += seg_len;
4695 tcpha->tha_ack = htonl(tcp->tcp_rnxt);
4696
4697 if (mp == NULL)
4698 goto xmit_check;
4699
4700 /* Update SACK list */
4701 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
4702 tcp_sack_remove(tcp->tcp_sack_list, tcp->tcp_rnxt,
4703 &(tcp->tcp_num_sack_blk));
4704 }
4705
4706 if (tcp->tcp_urp_mp) {
4707 tcp->tcp_urp_mp->b_cont = mp;
4708 mp = tcp->tcp_urp_mp;
4709 tcp->tcp_urp_mp = NULL;
4710 /* Ready for a new signal. */
4711 tcp->tcp_urp_last_valid = B_FALSE;
4712 #ifdef DEBUG
4713 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
4714 "tcp_rput: sending exdata_ind %s",
4715 tcp_display(tcp, NULL, DISP_PORT_ONLY));
4716 #endif /* DEBUG */
4717 }
4718
4719 /*
4720 * Check for ancillary data changes compared to last segment.
4721 */
4722 if (connp->conn_recv_ancillary.crb_all != 0) {
4723 mp = tcp_input_add_ancillary(tcp, mp, &ipp, ira);
4724 if (mp == NULL)
4725 return;
4726 }
4727
4728 if (IPCL_IS_NONSTR(connp)) {
4729 /*
4730 * Non-STREAMS socket
4731 */
4732 boolean_t push = flags & (TH_PUSH|TH_FIN);
4733 int error;
4734
4735 if ((*sockupcalls->su_recv)(connp->conn_upper_handle,
4736 mp, seg_len, 0, &error, &push) <= 0) {
4737 /*
4738 * We should never be in middle of a
4739 * fallback, the squeue guarantees that.
4740 */
4741 ASSERT(error != EOPNOTSUPP);
4742 if (error == ENOSPC)
4743 tcp->tcp_rwnd -= seg_len;
4744 } else if (push) {
4745 /* PUSH bit set and sockfs is not flow controlled */
4746 flags |= tcp_rwnd_reopen(tcp);
4747 }
4748 } else if (tcp->tcp_listener != NULL || tcp->tcp_hard_binding) {
4749 /*
4750 * Side queue inbound data until the accept happens.
4751 * tcp_accept/tcp_rput drains this when the accept happens.
4752 * M_DATA is queued on b_cont. Otherwise (T_OPTDATA_IND or
4753 * T_EXDATA_IND) it is queued on b_next.
4754 * XXX Make urgent data use this. Requires:
4755 * Removing tcp_listener check for TH_URG
4756 * Making M_PCPROTO and MARK messages skip the eager case
4757 */
4758
4759 tcp_rcv_enqueue(tcp, mp, seg_len, ira->ira_cred);
4760 } else {
4761 /* Active STREAMS socket */
4762 if (mp->b_datap->db_type != M_DATA ||
4763 (flags & TH_MARKNEXT_NEEDED)) {
4764 if (tcp->tcp_rcv_list != NULL) {
4765 flags |= tcp_rcv_drain(tcp);
4766 }
4767 ASSERT(tcp->tcp_rcv_list == NULL ||
4768 tcp->tcp_fused_sigurg);
4769
4770 if (flags & TH_MARKNEXT_NEEDED) {
4771 #ifdef DEBUG
4772 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
4773 "tcp_rput: sending MSGMARKNEXT %s",
4774 tcp_display(tcp, NULL,
4775 DISP_PORT_ONLY));
4776 #endif /* DEBUG */
4777 mp->b_flag |= MSGMARKNEXT;
4778 flags &= ~TH_MARKNEXT_NEEDED;
4779 }
4780
4781 if (is_system_labeled())
4782 tcp_setcred_data(mp, ira);
4783
4784 putnext(connp->conn_rq, mp);
4785 if (!canputnext(connp->conn_rq))
4786 tcp->tcp_rwnd -= seg_len;
4787 } else if ((flags & (TH_PUSH|TH_FIN)) ||
4788 tcp->tcp_rcv_cnt + seg_len >= connp->conn_rcvbuf >> 3) {
4789 if (tcp->tcp_rcv_list != NULL) {
4790 /*
4791 * Enqueue the new segment first and then
4792 * call tcp_rcv_drain() to send all data
4793 * up. The other way to do this is to
4794 * send all queued data up and then call
4795 * putnext() to send the new segment up.
4796 * This way can remove the else part later
4797 * on.
4798 *
4799 * We don't do this to avoid one more call to
4800 * canputnext() as tcp_rcv_drain() needs to
4801 * call canputnext().
4802 */
4803 tcp_rcv_enqueue(tcp, mp, seg_len,
4804 ira->ira_cred);
4805 flags |= tcp_rcv_drain(tcp);
4806 } else {
4807 if (is_system_labeled())
4808 tcp_setcred_data(mp, ira);
4809
4810 putnext(connp->conn_rq, mp);
4811 if (!canputnext(connp->conn_rq))
4812 tcp->tcp_rwnd -= seg_len;
4813 }
4814 } else {
4815 /*
4816 * Enqueue all packets when processing an mblk
4817 * from the co queue and also enqueue normal packets.
4818 */
4819 tcp_rcv_enqueue(tcp, mp, seg_len, ira->ira_cred);
4820 }
4821 /*
4822 * Make sure the timer is running if we have data waiting
4823 * for a push bit. This provides resiliency against
4824 * implementations that do not correctly generate push bits.
4825 */
4826 if (tcp->tcp_rcv_list != NULL && tcp->tcp_push_tid == 0) {
4827 /*
4828 * The connection may be closed at this point, so don't
4829 * do anything for a detached tcp.
4830 */
4831 if (!TCP_IS_DETACHED(tcp))
4832 tcp->tcp_push_tid = TCP_TIMER(tcp,
4833 tcp_push_timer,
4834 tcps->tcps_push_timer_interval);
4835 }
4836 }
4837
4838 xmit_check:
4839 /* Is there anything left to do? */
4840 ASSERT(!(flags & TH_MARKNEXT_NEEDED));
4841 if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_ACK_NEEDED|
4842 TH_NEED_SACK_REXMIT|TH_LIMIT_XMIT|TH_ACK_TIMER_NEEDED|
4843 TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
4844 goto done;
4845
4846 /* Any transmit work to do and a non-zero window? */
4847 if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_NEED_SACK_REXMIT|
4848 TH_LIMIT_XMIT)) && tcp->tcp_swnd != 0) {
4849 if (flags & TH_REXMIT_NEEDED) {
4850 uint32_t snd_size = tcp->tcp_snxt - tcp->tcp_suna;
4851
4852 TCPS_BUMP_MIB(tcps, tcpOutFastRetrans);
4853 if (snd_size > mss)
4854 snd_size = mss;
4855 if (snd_size > tcp->tcp_swnd)
4856 snd_size = tcp->tcp_swnd;
4857 mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, snd_size,
4858 NULL, NULL, tcp->tcp_suna, B_TRUE, &snd_size,
4859 B_TRUE);
4860
4861 if (mp1 != NULL) {
4862 tcp->tcp_xmit_head->b_prev =
4863 (mblk_t *)LBOLT_FASTPATH;
4864 tcp->tcp_csuna = tcp->tcp_snxt;
4865 TCPS_BUMP_MIB(tcps, tcpRetransSegs);
4866 TCPS_UPDATE_MIB(tcps, tcpRetransBytes,
4867 snd_size);
4868 tcp_send_data(tcp, mp1);
4869 }
4870 }
4871 if (flags & TH_NEED_SACK_REXMIT) {
4872 tcp_sack_rexmit(tcp, &flags);
4873 }
4874 /*
4875 * For TH_LIMIT_XMIT, tcp_wput_data() is called to send
4876 * out new segment. Note that tcp_rexmit should not be
4877 * set, otherwise TH_LIMIT_XMIT should not be set.
4878 */
4879 if (flags & (TH_XMIT_NEEDED|TH_LIMIT_XMIT)) {
4880 if (!tcp->tcp_rexmit) {
4881 tcp_wput_data(tcp, NULL, B_FALSE);
4882 } else {
4883 tcp_ss_rexmit(tcp);
4884 }
4885 }
4886 /*
4887 * Adjust tcp_cwnd back to normal value after sending
4888 * new data segments.
4889 */
4890 if (flags & TH_LIMIT_XMIT) {
4891 tcp->tcp_cwnd -= mss << (tcp->tcp_dupack_cnt - 1);
4892 /*
4893 * This will restart the timer. Restarting the
4894 * timer is used to avoid a timeout before the
4895 * limited transmitted segment's ACK gets back.
4896 */
4897 if (tcp->tcp_xmit_head != NULL)
4898 tcp->tcp_xmit_head->b_prev =
4899 (mblk_t *)LBOLT_FASTPATH;
4900 }
4901
4902 /* Anything more to do? */
4903 if ((flags & (TH_ACK_NEEDED|TH_ACK_TIMER_NEEDED|
4904 TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
4905 goto done;
4906 }
4907 ack_check:
4908 if (flags & TH_SEND_URP_MARK) {
4909 ASSERT(tcp->tcp_urp_mark_mp);
4910 ASSERT(!IPCL_IS_NONSTR(connp));
4911 /*
4912 * Send up any queued data and then send the mark message
4913 */
4914 if (tcp->tcp_rcv_list != NULL) {
4915 flags |= tcp_rcv_drain(tcp);
4916
4917 }
4918 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_fused_sigurg);
4919 mp1 = tcp->tcp_urp_mark_mp;
4920 tcp->tcp_urp_mark_mp = NULL;
4921 if (is_system_labeled())
4922 tcp_setcred_data(mp1, ira);
4923
4924 putnext(connp->conn_rq, mp1);
4925 #ifdef DEBUG
4926 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
4927 "tcp_rput: sending zero-length %s %s",
4928 ((mp1->b_flag & MSGMARKNEXT) ? "MSGMARKNEXT" :
4929 "MSGNOTMARKNEXT"),
4930 tcp_display(tcp, NULL, DISP_PORT_ONLY));
4931 #endif /* DEBUG */
4932 flags &= ~TH_SEND_URP_MARK;
4933 }
4934 if (flags & TH_ACK_NEEDED) {
4935 /*
4936 * Time to send an ack for some reason.
4937 */
4938 mp1 = tcp_ack_mp(tcp);
4939
4940 if (mp1 != NULL) {
4941 tcp_send_data(tcp, mp1);
4942 BUMP_LOCAL(tcp->tcp_obsegs);
4943 TCPS_BUMP_MIB(tcps, tcpOutAck);
4944 }
4945 if (tcp->tcp_ack_tid != 0) {
4946 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_ack_tid);
4947 tcp->tcp_ack_tid = 0;
4948 }
4949 }
4950 if (flags & TH_ACK_TIMER_NEEDED) {
4951 /*
4952 * Arrange for deferred ACK or push wait timeout.
4953 * Start timer if it is not already running.
4954 */
4955 if (tcp->tcp_ack_tid == 0) {
4956 tcp->tcp_ack_tid = TCP_TIMER(tcp, tcp_ack_timer,
4957 tcp->tcp_localnet ?
4958 tcps->tcps_local_dack_interval :
4959 tcps->tcps_deferred_ack_interval);
4960 }
4961 }
4962 if (flags & TH_ORDREL_NEEDED) {
4963 /*
4964 * Notify upper layer about an orderly release. If this is
4965 * a non-STREAMS socket, then just make an upcall. For STREAMS
4966 * we send up an ordrel_ind, unless this is an eager, in which
4967 * case the ordrel will be sent when tcp_accept_finish runs.
4968 * Note that for non-STREAMS we make an upcall even if it is an
4969 * eager, because we have an upper handle to send it to.
4970 */
4971 ASSERT(IPCL_IS_NONSTR(connp) || tcp->tcp_listener == NULL);
4972 ASSERT(!tcp->tcp_detached);
4973
4974 if (IPCL_IS_NONSTR(connp)) {
4975 ASSERT(tcp->tcp_ordrel_mp == NULL);
4976 tcp->tcp_ordrel_done = B_TRUE;
4977 (*sockupcalls->su_opctl)(connp->conn_upper_handle,
4978 SOCK_OPCTL_SHUT_RECV, 0);
4979 goto done;
4980 }
4981
4982 if (tcp->tcp_rcv_list != NULL) {
4983 /*
4984 * Push any mblk(s) enqueued from co processing.
4985 */
4986 flags |= tcp_rcv_drain(tcp);
4987 }
4988 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_fused_sigurg);
4989
4990 mp1 = tcp->tcp_ordrel_mp;
4991 tcp->tcp_ordrel_mp = NULL;
4992 tcp->tcp_ordrel_done = B_TRUE;
4993 putnext(connp->conn_rq, mp1);
4994 }
4995 done:
4996 ASSERT(!(flags & TH_MARKNEXT_NEEDED));
4997 }
4998
4999 /*
5000 * Attach ancillary data to a received TCP segments for the
5001 * ancillary pieces requested by the application that are
5002 * different than they were in the previous data segment.
5003 *
5004 * Save the "current" values once memory allocation is ok so that
5005 * when memory allocation fails we can just wait for the next data segment.
5006 */
5007 static mblk_t *
5008 tcp_input_add_ancillary(tcp_t *tcp, mblk_t *mp, ip_pkt_t *ipp,
5009 ip_recv_attr_t *ira)
5010 {
5011 struct T_optdata_ind *todi;
5012 int optlen;
5013 uchar_t *optptr;
5014 struct T_opthdr *toh;
5015 crb_t addflag; /* Which pieces to add */
5016 mblk_t *mp1;
5017 conn_t *connp = tcp->tcp_connp;
5018
5019 optlen = 0;
5020 addflag.crb_all = 0;
5021 /* If app asked for pktinfo and the index has changed ... */
5022 if (connp->conn_recv_ancillary.crb_ip_recvpktinfo &&
5023 ira->ira_ruifindex != tcp->tcp_recvifindex) {
5024 optlen += sizeof (struct T_opthdr) +
5025 sizeof (struct in6_pktinfo);
5026 addflag.crb_ip_recvpktinfo = 1;
5027 }
5028 /* If app asked for hoplimit and it has changed ... */
5029 if (connp->conn_recv_ancillary.crb_ipv6_recvhoplimit &&
5030 ipp->ipp_hoplimit != tcp->tcp_recvhops) {
5031 optlen += sizeof (struct T_opthdr) + sizeof (uint_t);
5032 addflag.crb_ipv6_recvhoplimit = 1;
5033 }
5034 /* If app asked for tclass and it has changed ... */
5035 if (connp->conn_recv_ancillary.crb_ipv6_recvtclass &&
5036 ipp->ipp_tclass != tcp->tcp_recvtclass) {
5037 optlen += sizeof (struct T_opthdr) + sizeof (uint_t);
5038 addflag.crb_ipv6_recvtclass = 1;
5039 }
5040 /*
5041 * If app asked for hopbyhop headers and it has changed ...
5042 * For security labels, note that (1) security labels can't change on
5043 * a connected socket at all, (2) we're connected to at most one peer,
5044 * (3) if anything changes, then it must be some other extra option.
5045 */
5046 if (connp->conn_recv_ancillary.crb_ipv6_recvhopopts &&
5047 ip_cmpbuf(tcp->tcp_hopopts, tcp->tcp_hopoptslen,
5048 (ipp->ipp_fields & IPPF_HOPOPTS),
5049 ipp->ipp_hopopts, ipp->ipp_hopoptslen)) {
5050 optlen += sizeof (struct T_opthdr) + ipp->ipp_hopoptslen;
5051 addflag.crb_ipv6_recvhopopts = 1;
5052 if (!ip_allocbuf((void **)&tcp->tcp_hopopts,
5053 &tcp->tcp_hopoptslen, (ipp->ipp_fields & IPPF_HOPOPTS),
5054 ipp->ipp_hopopts, ipp->ipp_hopoptslen))
5055 return (mp);
5056 }
5057 /* If app asked for dst headers before routing headers ... */
5058 if (connp->conn_recv_ancillary.crb_ipv6_recvrthdrdstopts &&
5059 ip_cmpbuf(tcp->tcp_rthdrdstopts, tcp->tcp_rthdrdstoptslen,
5060 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5061 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen)) {
5062 optlen += sizeof (struct T_opthdr) +
5063 ipp->ipp_rthdrdstoptslen;
5064 addflag.crb_ipv6_recvrthdrdstopts = 1;
5065 if (!ip_allocbuf((void **)&tcp->tcp_rthdrdstopts,
5066 &tcp->tcp_rthdrdstoptslen,
5067 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5068 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen))
5069 return (mp);
5070 }
5071 /* If app asked for routing headers and it has changed ... */
5072 if (connp->conn_recv_ancillary.crb_ipv6_recvrthdr &&
5073 ip_cmpbuf(tcp->tcp_rthdr, tcp->tcp_rthdrlen,
5074 (ipp->ipp_fields & IPPF_RTHDR),
5075 ipp->ipp_rthdr, ipp->ipp_rthdrlen)) {
5076 optlen += sizeof (struct T_opthdr) + ipp->ipp_rthdrlen;
5077 addflag.crb_ipv6_recvrthdr = 1;
5078 if (!ip_allocbuf((void **)&tcp->tcp_rthdr,
5079 &tcp->tcp_rthdrlen, (ipp->ipp_fields & IPPF_RTHDR),
5080 ipp->ipp_rthdr, ipp->ipp_rthdrlen))
5081 return (mp);
5082 }
5083 /* If app asked for dest headers and it has changed ... */
5084 if ((connp->conn_recv_ancillary.crb_ipv6_recvdstopts ||
5085 connp->conn_recv_ancillary.crb_old_ipv6_recvdstopts) &&
5086 ip_cmpbuf(tcp->tcp_dstopts, tcp->tcp_dstoptslen,
5087 (ipp->ipp_fields & IPPF_DSTOPTS),
5088 ipp->ipp_dstopts, ipp->ipp_dstoptslen)) {
5089 optlen += sizeof (struct T_opthdr) + ipp->ipp_dstoptslen;
5090 addflag.crb_ipv6_recvdstopts = 1;
5091 if (!ip_allocbuf((void **)&tcp->tcp_dstopts,
5092 &tcp->tcp_dstoptslen, (ipp->ipp_fields & IPPF_DSTOPTS),
5093 ipp->ipp_dstopts, ipp->ipp_dstoptslen))
5094 return (mp);
5095 }
5096
5097 if (optlen == 0) {
5098 /* Nothing to add */
5099 return (mp);
5100 }
5101 mp1 = allocb(sizeof (struct T_optdata_ind) + optlen, BPRI_MED);
5102 if (mp1 == NULL) {
5103 /*
5104 * Defer sending ancillary data until the next TCP segment
5105 * arrives.
5106 */
5107 return (mp);
5108 }
5109 mp1->b_cont = mp;
5110 mp = mp1;
5111 mp->b_wptr += sizeof (*todi) + optlen;
5112 mp->b_datap->db_type = M_PROTO;
5113 todi = (struct T_optdata_ind *)mp->b_rptr;
5114 todi->PRIM_type = T_OPTDATA_IND;
5115 todi->DATA_flag = 1; /* MORE data */
5116 todi->OPT_length = optlen;
5117 todi->OPT_offset = sizeof (*todi);
5118 optptr = (uchar_t *)&todi[1];
5119 /*
5120 * If app asked for pktinfo and the index has changed ...
5121 * Note that the local address never changes for the connection.
5122 */
5123 if (addflag.crb_ip_recvpktinfo) {
5124 struct in6_pktinfo *pkti;
5125 uint_t ifindex;
5126
5127 ifindex = ira->ira_ruifindex;
5128 toh = (struct T_opthdr *)optptr;
5129 toh->level = IPPROTO_IPV6;
5130 toh->name = IPV6_PKTINFO;
5131 toh->len = sizeof (*toh) + sizeof (*pkti);
5132 toh->status = 0;
5133 optptr += sizeof (*toh);
5134 pkti = (struct in6_pktinfo *)optptr;
5135 pkti->ipi6_addr = connp->conn_laddr_v6;
5136 pkti->ipi6_ifindex = ifindex;
5137 optptr += sizeof (*pkti);
5138 ASSERT(OK_32PTR(optptr));
5139 /* Save as "last" value */
5140 tcp->tcp_recvifindex = ifindex;
5141 }
5142 /* If app asked for hoplimit and it has changed ... */
5143 if (addflag.crb_ipv6_recvhoplimit) {
5144 toh = (struct T_opthdr *)optptr;
5145 toh->level = IPPROTO_IPV6;
5146 toh->name = IPV6_HOPLIMIT;
5147 toh->len = sizeof (*toh) + sizeof (uint_t);
5148 toh->status = 0;
5149 optptr += sizeof (*toh);
5150 *(uint_t *)optptr = ipp->ipp_hoplimit;
5151 optptr += sizeof (uint_t);
5152 ASSERT(OK_32PTR(optptr));
5153 /* Save as "last" value */
5154 tcp->tcp_recvhops = ipp->ipp_hoplimit;
5155 }
5156 /* If app asked for tclass and it has changed ... */
5157 if (addflag.crb_ipv6_recvtclass) {
5158 toh = (struct T_opthdr *)optptr;
5159 toh->level = IPPROTO_IPV6;
5160 toh->name = IPV6_TCLASS;
5161 toh->len = sizeof (*toh) + sizeof (uint_t);
5162 toh->status = 0;
5163 optptr += sizeof (*toh);
5164 *(uint_t *)optptr = ipp->ipp_tclass;
5165 optptr += sizeof (uint_t);
5166 ASSERT(OK_32PTR(optptr));
5167 /* Save as "last" value */
5168 tcp->tcp_recvtclass = ipp->ipp_tclass;
5169 }
5170 if (addflag.crb_ipv6_recvhopopts) {
5171 toh = (struct T_opthdr *)optptr;
5172 toh->level = IPPROTO_IPV6;
5173 toh->name = IPV6_HOPOPTS;
5174 toh->len = sizeof (*toh) + ipp->ipp_hopoptslen;
5175 toh->status = 0;
5176 optptr += sizeof (*toh);
5177 bcopy((uchar_t *)ipp->ipp_hopopts, optptr, ipp->ipp_hopoptslen);
5178 optptr += ipp->ipp_hopoptslen;
5179 ASSERT(OK_32PTR(optptr));
5180 /* Save as last value */
5181 ip_savebuf((void **)&tcp->tcp_hopopts, &tcp->tcp_hopoptslen,
5182 (ipp->ipp_fields & IPPF_HOPOPTS),
5183 ipp->ipp_hopopts, ipp->ipp_hopoptslen);
5184 }
5185 if (addflag.crb_ipv6_recvrthdrdstopts) {
5186 toh = (struct T_opthdr *)optptr;
5187 toh->level = IPPROTO_IPV6;
5188 toh->name = IPV6_RTHDRDSTOPTS;
5189 toh->len = sizeof (*toh) + ipp->ipp_rthdrdstoptslen;
5190 toh->status = 0;
5191 optptr += sizeof (*toh);
5192 bcopy(ipp->ipp_rthdrdstopts, optptr, ipp->ipp_rthdrdstoptslen);
5193 optptr += ipp->ipp_rthdrdstoptslen;
5194 ASSERT(OK_32PTR(optptr));
5195 /* Save as last value */
5196 ip_savebuf((void **)&tcp->tcp_rthdrdstopts,
5197 &tcp->tcp_rthdrdstoptslen,
5198 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5199 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen);
5200 }
5201 if (addflag.crb_ipv6_recvrthdr) {
5202 toh = (struct T_opthdr *)optptr;
5203 toh->level = IPPROTO_IPV6;
5204 toh->name = IPV6_RTHDR;
5205 toh->len = sizeof (*toh) + ipp->ipp_rthdrlen;
5206 toh->status = 0;
5207 optptr += sizeof (*toh);
5208 bcopy(ipp->ipp_rthdr, optptr, ipp->ipp_rthdrlen);
5209 optptr += ipp->ipp_rthdrlen;
5210 ASSERT(OK_32PTR(optptr));
5211 /* Save as last value */
5212 ip_savebuf((void **)&tcp->tcp_rthdr, &tcp->tcp_rthdrlen,
5213 (ipp->ipp_fields & IPPF_RTHDR),
5214 ipp->ipp_rthdr, ipp->ipp_rthdrlen);
5215 }
5216 if (addflag.crb_ipv6_recvdstopts) {
5217 toh = (struct T_opthdr *)optptr;
5218 toh->level = IPPROTO_IPV6;
5219 toh->name = IPV6_DSTOPTS;
5220 toh->len = sizeof (*toh) + ipp->ipp_dstoptslen;
5221 toh->status = 0;
5222 optptr += sizeof (*toh);
5223 bcopy(ipp->ipp_dstopts, optptr, ipp->ipp_dstoptslen);
5224 optptr += ipp->ipp_dstoptslen;
5225 ASSERT(OK_32PTR(optptr));
5226 /* Save as last value */
5227 ip_savebuf((void **)&tcp->tcp_dstopts, &tcp->tcp_dstoptslen,
5228 (ipp->ipp_fields & IPPF_DSTOPTS),
5229 ipp->ipp_dstopts, ipp->ipp_dstoptslen);
5230 }
5231 ASSERT(optptr == mp->b_wptr);
5232 return (mp);
5233 }
5234
5235 /* The minimum of smoothed mean deviation in RTO calculation. */
5236 #define TCP_SD_MIN 400
5237
5238 /*
5239 * Set RTO for this connection. The formula is from Jacobson and Karels'
5240 * "Congestion Avoidance and Control" in SIGCOMM '88. The variable names
5241 * are the same as those in Appendix A.2 of that paper.
5242 *
5243 * m = new measurement
5244 * sa = smoothed RTT average (8 * average estimates).
5245 * sv = smoothed mean deviation (mdev) of RTT (4 * deviation estimates).
5246 */
5247 static void
5248 tcp_set_rto(tcp_t *tcp, clock_t rtt)
5249 {
5250 long m = TICK_TO_MSEC(rtt);
5251 clock_t sa = tcp->tcp_rtt_sa;
5252 clock_t sv = tcp->tcp_rtt_sd;
5253 clock_t rto;
5254 tcp_stack_t *tcps = tcp->tcp_tcps;
5255
5256 TCPS_BUMP_MIB(tcps, tcpRttUpdate);
5257 tcp->tcp_rtt_update++;
5258
5259 /* tcp_rtt_sa is not 0 means this is a new sample. */
5260 if (sa != 0) {
5261 /*
5262 * Update average estimator:
5263 * new rtt = 7/8 old rtt + 1/8 Error
5264 */
5265
5266 /* m is now Error in estimate. */
5267 m -= sa >> 3;
5268 if ((sa += m) <= 0) {
5269 /*
5270 * Don't allow the smoothed average to be negative.
5271 * We use 0 to denote reinitialization of the
5272 * variables.
5273 */
5274 sa = 1;
5275 }
5276
5277 /*
5278 * Update deviation estimator:
5279 * new mdev = 3/4 old mdev + 1/4 (abs(Error) - old mdev)
5280 */
5281 if (m < 0)
5282 m = -m;
5283 m -= sv >> 2;
5284 sv += m;
5285 } else {
5286 /*
5287 * This follows BSD's implementation. So the reinitialized
5288 * RTO is 3 * m. We cannot go less than 2 because if the
5289 * link is bandwidth dominated, doubling the window size
5290 * during slow start means doubling the RTT. We want to be
5291 * more conservative when we reinitialize our estimates. 3
5292 * is just a convenient number.
5293 */
5294 sa = m << 3;
5295 sv = m << 1;
5296 }
5297 if (sv < TCP_SD_MIN) {
5298 /*
5299 * We do not know that if sa captures the delay ACK
5300 * effect as in a long train of segments, a receiver
5301 * does not delay its ACKs. So set the minimum of sv
5302 * to be TCP_SD_MIN, which is default to 400 ms, twice
5303 * of BSD DATO. That means the minimum of mean
5304 * deviation is 100 ms.
5305 *
5306 */
5307 sv = TCP_SD_MIN;
5308 }
5309 tcp->tcp_rtt_sa = sa;
5310 tcp->tcp_rtt_sd = sv;
5311 /*
5312 * RTO = average estimates (sa / 8) + 4 * deviation estimates (sv)
5313 *
5314 * Add tcp_rexmit_interval extra in case of extreme environment
5315 * where the algorithm fails to work. The default value of
5316 * tcp_rexmit_interval_extra should be 0.
5317 *
5318 * As we use a finer grained clock than BSD and update
5319 * RTO for every ACKs, add in another .25 of RTT to the
5320 * deviation of RTO to accomodate burstiness of 1/4 of
5321 * window size.
5322 */
5323 rto = (sa >> 3) + sv + tcps->tcps_rexmit_interval_extra + (sa >> 5);
5324
5325 TCP_SET_RTO(tcp, rto);
5326
5327 /* Now, we can reset tcp_timer_backoff to use the new RTO... */
5328 tcp->tcp_timer_backoff = 0;
5329 }
5330
5331 /*
5332 * On a labeled system we have some protocols above TCP, such as RPC, which
5333 * appear to assume that every mblk in a chain has a db_credp.
5334 */
5335 static void
5336 tcp_setcred_data(mblk_t *mp, ip_recv_attr_t *ira)
5337 {
5338 ASSERT(is_system_labeled());
5339 ASSERT(ira->ira_cred != NULL);
5340
5341 while (mp != NULL) {
5342 mblk_setcred(mp, ira->ira_cred, NOPID);
5343 mp = mp->b_cont;
5344 }
5345 }
5346
5347 uint_t
5348 tcp_rwnd_reopen(tcp_t *tcp)
5349 {
5350 uint_t ret = 0;
5351 uint_t thwin;
5352 conn_t *connp = tcp->tcp_connp;
5353
5354 /* Learn the latest rwnd information that we sent to the other side. */
5355 thwin = ((uint_t)ntohs(tcp->tcp_tcpha->tha_win))
5356 << tcp->tcp_rcv_ws;
5357 /* This is peer's calculated send window (our receive window). */
5358 thwin -= tcp->tcp_rnxt - tcp->tcp_rack;
5359 /*
5360 * Increase the receive window to max. But we need to do receiver
5361 * SWS avoidance. This means that we need to check the increase of
5362 * of receive window is at least 1 MSS.
5363 */
5364 if (connp->conn_rcvbuf - thwin >= tcp->tcp_mss) {
5365 /*
5366 * If the window that the other side knows is less than max
5367 * deferred acks segments, send an update immediately.
5368 */
5369 if (thwin < tcp->tcp_rack_cur_max * tcp->tcp_mss) {
5370 TCPS_BUMP_MIB(tcp->tcp_tcps, tcpOutWinUpdate);
5371 ret = TH_ACK_NEEDED;
5372 }
5373 tcp->tcp_rwnd = connp->conn_rcvbuf;
5374 }
5375 return (ret);
5376 }
5377
5378 /*
5379 * Handle a packet that has been reclassified by TCP.
5380 * This function drops the ref on connp that the caller had.
5381 */
5382 void
5383 tcp_reinput(conn_t *connp, mblk_t *mp, ip_recv_attr_t *ira, ip_stack_t *ipst)
5384 {
5385 ipsec_stack_t *ipss = ipst->ips_netstack->netstack_ipsec;
5386
5387 if (connp->conn_incoming_ifindex != 0 &&
5388 connp->conn_incoming_ifindex != ira->ira_ruifindex) {
5389 freemsg(mp);
5390 CONN_DEC_REF(connp);
5391 return;
5392 }
5393
5394 if (CONN_INBOUND_POLICY_PRESENT_V6(connp, ipss) ||
5395 (ira->ira_flags & IRAF_IPSEC_SECURE)) {
5396 ip6_t *ip6h;
5397 ipha_t *ipha;
5398
5399 if (ira->ira_flags & IRAF_IS_IPV4) {
5400 ipha = (ipha_t *)mp->b_rptr;
5401 ip6h = NULL;
5402 } else {
5403 ipha = NULL;
5404 ip6h = (ip6_t *)mp->b_rptr;
5405 }
5406 mp = ipsec_check_inbound_policy(mp, connp, ipha, ip6h, ira);
5407 if (mp == NULL) {
5408 BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsInDiscards);
5409 /* Note that mp is NULL */
5410 ip_drop_input("ipIfStatsInDiscards", mp, NULL);
5411 CONN_DEC_REF(connp);
5412 return;
5413 }
5414 }
5415
5416 if (IPCL_IS_TCP(connp)) {
5417 /*
5418 * do not drain, certain use cases can blow
5419 * the stack
5420 */
5421 SQUEUE_ENTER_ONE(connp->conn_sqp, mp,
5422 connp->conn_recv, connp, ira,
5423 SQ_NODRAIN, SQTAG_IP_TCP_INPUT);
5424 } else {
5425 /* Not TCP; must be SOCK_RAW, IPPROTO_TCP */
5426 (connp->conn_recv)(connp, mp, NULL,
5427 ira);
5428 CONN_DEC_REF(connp);
5429 }
5430
5431 }
5432
5433 /* ARGSUSED */
5434 static void
5435 tcp_rsrv_input(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
5436 {
5437 conn_t *connp = (conn_t *)arg;
5438 tcp_t *tcp = connp->conn_tcp;
5439 queue_t *q = connp->conn_rq;
5440
5441 ASSERT(!IPCL_IS_NONSTR(connp));
5442 mutex_enter(&tcp->tcp_rsrv_mp_lock);
5443 tcp->tcp_rsrv_mp = mp;
5444 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5445
5446 if (TCP_IS_DETACHED(tcp) || q == NULL) {
5447 return;
5448 }
5449
5450 if (tcp->tcp_fused) {
5451 tcp_fuse_backenable(tcp);
5452 return;
5453 }
5454
5455 if (canputnext(q)) {
5456 /* Not flow-controlled, open rwnd */
5457 tcp->tcp_rwnd = connp->conn_rcvbuf;
5458
5459 /*
5460 * Send back a window update immediately if TCP is above
5461 * ESTABLISHED state and the increase of the rcv window
5462 * that the other side knows is at least 1 MSS after flow
5463 * control is lifted.
5464 */
5465 if (tcp->tcp_state >= TCPS_ESTABLISHED &&
5466 tcp_rwnd_reopen(tcp) == TH_ACK_NEEDED) {
5467 tcp_xmit_ctl(NULL, tcp,
5468 (tcp->tcp_swnd == 0) ? tcp->tcp_suna :
5469 tcp->tcp_snxt, tcp->tcp_rnxt, TH_ACK);
5470 }
5471 }
5472 }
5473
5474 /*
5475 * The read side service routine is called mostly when we get back-enabled as a
5476 * result of flow control relief. Since we don't actually queue anything in
5477 * TCP, we have no data to send out of here. What we do is clear the receive
5478 * window, and send out a window update.
5479 */
5480 void
5481 tcp_rsrv(queue_t *q)
5482 {
5483 conn_t *connp = Q_TO_CONN(q);
5484 tcp_t *tcp = connp->conn_tcp;
5485 mblk_t *mp;
5486
5487 /* No code does a putq on the read side */
5488 ASSERT(q->q_first == NULL);
5489
5490 /*
5491 * If tcp->tcp_rsrv_mp == NULL, it means that tcp_rsrv() has already
5492 * been run. So just return.
5493 */
5494 mutex_enter(&tcp->tcp_rsrv_mp_lock);
5495 if ((mp = tcp->tcp_rsrv_mp) == NULL) {
5496 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5497 return;
5498 }
5499 tcp->tcp_rsrv_mp = NULL;
5500 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5501
5502 CONN_INC_REF(connp);
5503 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, tcp_rsrv_input, connp,
5504 NULL, SQ_PROCESS, SQTAG_TCP_RSRV);
5505 }
5506
5507 /* At minimum we need 8 bytes in the TCP header for the lookup */
5508 #define ICMP_MIN_TCP_HDR 8
5509
5510 /*
5511 * tcp_icmp_input is called as conn_recvicmp to process ICMP error messages
5512 * passed up by IP. The message is always received on the correct tcp_t.
5513 * Assumes that IP has pulled up everything up to and including the ICMP header.
5514 */
5515 /* ARGSUSED2 */
5516 void
5517 tcp_icmp_input(void *arg1, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
5518 {
5519 conn_t *connp = (conn_t *)arg1;
5520 icmph_t *icmph;
5521 ipha_t *ipha;
5522 int iph_hdr_length;
5523 tcpha_t *tcpha;
5524 uint32_t seg_seq;
5525 tcp_t *tcp = connp->conn_tcp;
5526
5527 /* Assume IP provides aligned packets */
5528 ASSERT(OK_32PTR(mp->b_rptr));
5529 ASSERT((MBLKL(mp) >= sizeof (ipha_t)));
5530
5531 /*
5532 * It's possible we have a closed, but not yet destroyed, TCP
5533 * connection. Several fields (e.g. conn_ixa->ixa_ire) are invalid
5534 * in the closed state, so don't take any chances and drop the packet.
5535 */
5536 if (tcp->tcp_state == TCPS_CLOSED) {
5537 freemsg(mp);
5538 return;
5539 }
5540
5541 /*
5542 * Verify IP version. Anything other than IPv4 or IPv6 packet is sent
5543 * upstream. ICMPv6 is handled in tcp_icmp_error_ipv6.
5544 */
5545 if (!(ira->ira_flags & IRAF_IS_IPV4)) {
5546 tcp_icmp_error_ipv6(tcp, mp, ira);
5547 return;
5548 }
5549
5550 /* Skip past the outer IP and ICMP headers */
5551 iph_hdr_length = ira->ira_ip_hdr_length;
5552 icmph = (icmph_t *)&mp->b_rptr[iph_hdr_length];
5553 /*
5554 * If we don't have the correct outer IP header length
5555 * or if we don't have a complete inner IP header
5556 * drop it.
5557 */
5558 if (iph_hdr_length < sizeof (ipha_t) ||
5559 (ipha_t *)&icmph[1] + 1 > (ipha_t *)mp->b_wptr) {
5560 noticmpv4:
5561 freemsg(mp);
5562 return;
5563 }
5564 ipha = (ipha_t *)&icmph[1];
5565
5566 /* Skip past the inner IP and find the ULP header */
5567 iph_hdr_length = IPH_HDR_LENGTH(ipha);
5568 tcpha = (tcpha_t *)((char *)ipha + iph_hdr_length);
5569 /*
5570 * If we don't have the correct inner IP header length or if the ULP
5571 * is not IPPROTO_TCP or if we don't have at least ICMP_MIN_TCP_HDR
5572 * bytes of TCP header, drop it.
5573 */
5574 if (iph_hdr_length < sizeof (ipha_t) ||
5575 ipha->ipha_protocol != IPPROTO_TCP ||
5576 (uchar_t *)tcpha + ICMP_MIN_TCP_HDR > mp->b_wptr) {
5577 goto noticmpv4;
5578 }
5579
5580 seg_seq = ntohl(tcpha->tha_seq);
5581 switch (icmph->icmph_type) {
5582 case ICMP_DEST_UNREACHABLE:
5583 switch (icmph->icmph_code) {
5584 case ICMP_FRAGMENTATION_NEEDED:
5585 /*
5586 * Update Path MTU, then try to send something out.
5587 */
5588 tcp_update_pmtu(tcp, B_TRUE);
5589 tcp_rexmit_after_error(tcp);
5590 break;
5591 case ICMP_PORT_UNREACHABLE:
5592 case ICMP_PROTOCOL_UNREACHABLE:
5593 switch (tcp->tcp_state) {
5594 case TCPS_SYN_SENT:
5595 case TCPS_SYN_RCVD:
5596 /*
5597 * ICMP can snipe away incipient
5598 * TCP connections as long as
5599 * seq number is same as initial
5600 * send seq number.
5601 */
5602 if (seg_seq == tcp->tcp_iss) {
5603 (void) tcp_clean_death(tcp,
5604 ECONNREFUSED);
5605 }
5606 break;
5607 }
5608 break;
5609 case ICMP_HOST_UNREACHABLE:
5610 case ICMP_NET_UNREACHABLE:
5611 /* Record the error in case we finally time out. */
5612 if (icmph->icmph_code == ICMP_HOST_UNREACHABLE)
5613 tcp->tcp_client_errno = EHOSTUNREACH;
5614 else
5615 tcp->tcp_client_errno = ENETUNREACH;
5616 if (tcp->tcp_state == TCPS_SYN_RCVD) {
5617 if (tcp->tcp_listener != NULL &&
5618 tcp->tcp_listener->tcp_syn_defense) {
5619 /*
5620 * Ditch the half-open connection if we
5621 * suspect a SYN attack is under way.
5622 */
5623 (void) tcp_clean_death(tcp,
5624 tcp->tcp_client_errno);
5625 }
5626 }
5627 break;
5628 default:
5629 break;
5630 }
5631 break;
5632 case ICMP_SOURCE_QUENCH: {
5633 /*
5634 * use a global boolean to control
5635 * whether TCP should respond to ICMP_SOURCE_QUENCH.
5636 * The default is false.
5637 */
5638 if (tcp_icmp_source_quench) {
5639 /*
5640 * Reduce the sending rate as if we got a
5641 * retransmit timeout
5642 */
5643 uint32_t npkt;
5644
5645 npkt = ((tcp->tcp_snxt - tcp->tcp_suna) >> 1) /
5646 tcp->tcp_mss;
5647 tcp->tcp_cwnd_ssthresh = MAX(npkt, 2) * tcp->tcp_mss;
5648 tcp->tcp_cwnd = tcp->tcp_mss;
5649 tcp->tcp_cwnd_cnt = 0;
5650 }
5651 break;
5652 }
5653 }
5654 freemsg(mp);
5655 }
5656
5657 /*
5658 * tcp_icmp_error_ipv6 is called from tcp_icmp_input to process ICMPv6
5659 * error messages passed up by IP.
5660 * Assumes that IP has pulled up all the extension headers as well
5661 * as the ICMPv6 header.
5662 */
5663 static void
5664 tcp_icmp_error_ipv6(tcp_t *tcp, mblk_t *mp, ip_recv_attr_t *ira)
5665 {
5666 icmp6_t *icmp6;
5667 ip6_t *ip6h;
5668 uint16_t iph_hdr_length = ira->ira_ip_hdr_length;
5669 tcpha_t *tcpha;
5670 uint8_t *nexthdrp;
5671 uint32_t seg_seq;
5672
5673 /*
5674 * Verify that we have a complete IP header.
5675 */
5676 ASSERT((MBLKL(mp) >= sizeof (ip6_t)));
5677
5678 icmp6 = (icmp6_t *)&mp->b_rptr[iph_hdr_length];
5679 ip6h = (ip6_t *)&icmp6[1];
5680 /*
5681 * Verify if we have a complete ICMP and inner IP header.
5682 */
5683 if ((uchar_t *)&ip6h[1] > mp->b_wptr) {
5684 noticmpv6:
5685 freemsg(mp);
5686 return;
5687 }
5688
5689 if (!ip_hdr_length_nexthdr_v6(mp, ip6h, &iph_hdr_length, &nexthdrp))
5690 goto noticmpv6;
5691 tcpha = (tcpha_t *)((char *)ip6h + iph_hdr_length);
5692 /*
5693 * Validate inner header. If the ULP is not IPPROTO_TCP or if we don't
5694 * have at least ICMP_MIN_TCP_HDR bytes of TCP header drop the
5695 * packet.
5696 */
5697 if ((*nexthdrp != IPPROTO_TCP) ||
5698 ((uchar_t *)tcpha + ICMP_MIN_TCP_HDR) > mp->b_wptr) {
5699 goto noticmpv6;
5700 }
5701
5702 seg_seq = ntohl(tcpha->tha_seq);
5703 switch (icmp6->icmp6_type) {
5704 case ICMP6_PACKET_TOO_BIG:
5705 /*
5706 * Update Path MTU, then try to send something out.
5707 */
5708 tcp_update_pmtu(tcp, B_TRUE);
5709 tcp_rexmit_after_error(tcp);
5710 break;
5711 case ICMP6_DST_UNREACH:
5712 switch (icmp6->icmp6_code) {
5713 case ICMP6_DST_UNREACH_NOPORT:
5714 if (((tcp->tcp_state == TCPS_SYN_SENT) ||
5715 (tcp->tcp_state == TCPS_SYN_RCVD)) &&
5716 (seg_seq == tcp->tcp_iss)) {
5717 (void) tcp_clean_death(tcp, ECONNREFUSED);
5718 }
5719 break;
5720 case ICMP6_DST_UNREACH_ADMIN:
5721 case ICMP6_DST_UNREACH_NOROUTE:
5722 case ICMP6_DST_UNREACH_BEYONDSCOPE:
5723 case ICMP6_DST_UNREACH_ADDR:
5724 /* Record the error in case we finally time out. */
5725 tcp->tcp_client_errno = EHOSTUNREACH;
5726 if (((tcp->tcp_state == TCPS_SYN_SENT) ||
5727 (tcp->tcp_state == TCPS_SYN_RCVD)) &&
5728 (seg_seq == tcp->tcp_iss)) {
5729 if (tcp->tcp_listener != NULL &&
5730 tcp->tcp_listener->tcp_syn_defense) {
5731 /*
5732 * Ditch the half-open connection if we
5733 * suspect a SYN attack is under way.
5734 */
5735 (void) tcp_clean_death(tcp,
5736 tcp->tcp_client_errno);
5737 }
5738 }
5739
5740
5741 break;
5742 default:
5743 break;
5744 }
5745 break;
5746 case ICMP6_PARAM_PROB:
5747 /* If this corresponds to an ICMP_PROTOCOL_UNREACHABLE */
5748 if (icmp6->icmp6_code == ICMP6_PARAMPROB_NEXTHEADER &&
5749 (uchar_t *)ip6h + icmp6->icmp6_pptr ==
5750 (uchar_t *)nexthdrp) {
5751 if (tcp->tcp_state == TCPS_SYN_SENT ||
5752 tcp->tcp_state == TCPS_SYN_RCVD) {
5753 (void) tcp_clean_death(tcp, ECONNREFUSED);
5754 }
5755 break;
5756 }
5757 break;
5758
5759 case ICMP6_TIME_EXCEEDED:
5760 default:
5761 break;
5762 }
5763 freemsg(mp);
5764 }
5765
5766 /*
5767 * CALLED OUTSIDE OF SQUEUE! It can not follow any pointers that tcp might
5768 * change. But it can refer to fields like tcp_suna and tcp_snxt.
5769 *
5770 * Function tcp_verifyicmp is called as conn_verifyicmp to verify the ICMP
5771 * error messages received by IP. The message is always received on the correct
5772 * tcp_t.
5773 */
5774 /* ARGSUSED */
5775 boolean_t
5776 tcp_verifyicmp(conn_t *connp, void *arg2, icmph_t *icmph, icmp6_t *icmp6,
5777 ip_recv_attr_t *ira)
5778 {
5779 tcpha_t *tcpha = (tcpha_t *)arg2;
5780 uint32_t seq = ntohl(tcpha->tha_seq);
5781 tcp_t *tcp = connp->conn_tcp;
5782
5783 /*
5784 * TCP sequence number contained in payload of the ICMP error message
5785 * should be within the range SND.UNA <= SEG.SEQ < SND.NXT. Otherwise,
5786 * the message is either a stale ICMP error, or an attack from the
5787 * network. Fail the verification.
5788 */
5789 if (SEQ_LT(seq, tcp->tcp_suna) || SEQ_GEQ(seq, tcp->tcp_snxt))
5790 return (B_FALSE);
5791
5792 /* For "too big" we also check the ignore flag */
5793 if (ira->ira_flags & IRAF_IS_IPV4) {
5794 ASSERT(icmph != NULL);
5795 if (icmph->icmph_type == ICMP_DEST_UNREACHABLE &&
5796 icmph->icmph_code == ICMP_FRAGMENTATION_NEEDED &&
5797 tcp->tcp_tcps->tcps_ignore_path_mtu)
5798 return (B_FALSE);
5799 } else {
5800 ASSERT(icmp6 != NULL);
5801 if (icmp6->icmp6_type == ICMP6_PACKET_TOO_BIG &&
5802 tcp->tcp_tcps->tcps_ignore_path_mtu)
5803 return (B_FALSE);
5804 }
5805 return (B_TRUE);
5806 }