1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  23  */
  24 /* Copyright (c) 1990 Mentat Inc. */
  25 
  26 #ifndef _INET_TCP_H
  27 #define _INET_TCP_H
  28 
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32 
  33 #include <sys/inttypes.h>
  34 #include <netinet/ip6.h>
  35 #include <netinet/tcp.h>
  36 #include <sys/socket.h>
  37 #include <sys/socket_proto.h>
  38 #include <sys/md5.h>
  39 #include <inet/common.h>
  40 #include <inet/ip.h>
  41 #include <inet/ip6.h>
  42 #include <inet/mi.h>
  43 #include <inet/mib2.h>
  44 #include <inet/tcp_stack.h>
  45 #include <inet/tcp_sack.h>
  46 
  47 /* TCP states */
  48 #define TCPS_CLOSED             -6
  49 #define TCPS_IDLE               -5      /* idle (opened, but not bound) */
  50 #define TCPS_BOUND              -4      /* bound, ready to connect or accept */
  51 #define TCPS_LISTEN             -3      /* listening for connection */
  52 #define TCPS_SYN_SENT           -2      /* active, have sent syn */
  53 #define TCPS_SYN_RCVD           -1      /* have received syn (and sent ours) */
  54 /* states < TCPS_ESTABLISHED are those where connections not established */
  55 #define TCPS_ESTABLISHED        0       /* established */
  56 #define TCPS_CLOSE_WAIT         1       /* rcvd fin, waiting for close */
  57 /* states > TCPS_CLOSE_WAIT are those where user has closed */
  58 #define TCPS_FIN_WAIT_1         2       /* have closed and sent fin */
  59 #define TCPS_CLOSING            3       /* closed, xchd FIN, await FIN ACK */
  60 #define TCPS_LAST_ACK           4       /* had fin and close; await FIN ACK */
  61 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
  62 #define TCPS_FIN_WAIT_2         5       /* have closed, fin is acked */
  63 #define TCPS_TIME_WAIT          6       /* in 2*msl quiet wait after close */
  64 
  65 /*
  66  * Internal flags used in conjunction with the packet header flags.
  67  * Used in tcp_input_data to keep track of what needs to be done.
  68  */
  69 #define TH_LIMIT_XMIT           0x0400  /* Limited xmit is needed */
  70 #define TH_XMIT_NEEDED          0x0800  /* Window opened - send queued data */
  71 #define TH_REXMIT_NEEDED        0x1000  /* Time expired for unacked data */
  72 #define TH_ACK_NEEDED           0x2000  /* Send an ack now. */
  73 #define TH_NEED_SACK_REXMIT     0x4000  /* Use SACK info to retransmission */
  74 #define TH_ACK_TIMER_NEEDED     0x8000  /* Start the delayed ACK timer */
  75 #define TH_ORDREL_NEEDED        0x10000 /* Generate an ordrel indication */
  76 #define TH_MARKNEXT_NEEDED      0x20000 /* Data should have MSGMARKNEXT */
  77 #define TH_SEND_URP_MARK        0x40000 /* Send up tcp_urp_mark_mp */
  78 
  79 /*
  80  * TCP sequence numbers are 32 bit integers operated
  81  * on with modular arithmetic.  These macros can be
  82  * used to compare such integers.
  83  */
  84 #define SEQ_LT(a, b)    ((int32_t)((a)-(b)) < 0)
  85 #define SEQ_LEQ(a, b)   ((int32_t)((a)-(b)) <= 0)
  86 #define SEQ_GT(a, b)    ((int32_t)((a)-(b)) > 0)
  87 #define SEQ_GEQ(a, b)   ((int32_t)((a)-(b)) >= 0)
  88 
  89 /* TCP Protocol header */
  90 typedef struct tcphdr_s {
  91         uint8_t         th_lport[2];    /* Source port */
  92         uint8_t         th_fport[2];    /* Destination port */
  93         uint8_t         th_seq[4];      /* Sequence number */
  94         uint8_t         th_ack[4];      /* Acknowledgement number */
  95         uint8_t         th_offset_and_rsrvd[1]; /* Offset to the packet data */
  96         uint8_t         th_flags[1];
  97         uint8_t         th_win[2];      /* Allocation number */
  98         uint8_t         th_sum[2];      /* TCP checksum */
  99         uint8_t         th_urp[2];      /* Urgent pointer */
 100 } tcph_t;
 101 
 102 #define TCP_HDR_LENGTH(tcph) \
 103         ((((tcph_t *)tcph)->th_offset_and_rsrvd[0] >>2) &(0xF << 2))
 104 #define TCP_MAX_COMBINED_HEADER_LENGTH  (60 + 60) /* Maxed out ip + tcp */
 105 #define TCP_MAX_IP_OPTIONS_LENGTH       (60 - IP_SIMPLE_HDR_LENGTH)
 106 #define TCP_MAX_HDR_LENGTH              60
 107 #define TCP_MAX_TCP_OPTIONS_LENGTH      (60 - sizeof (tcpha_t))
 108 #define TCP_MIN_HEADER_LENGTH           20
 109 #define TCP_MAXWIN                      65535
 110 #define TCP_PORT_LEN                    sizeof (in_port_t)
 111 #define TCP_MAX_WINSHIFT                14
 112 #define TCP_MAX_LARGEWIN                (TCP_MAXWIN << TCP_MAX_WINSHIFT)
 113 #define TCP_MAX_LSO_LENGTH      (IP_MAXPACKET - TCP_MAX_COMBINED_HEADER_LENGTH)
 114 
 115 #define TCPIP_HDR_LENGTH(mp, n)                                 \
 116         (n) = IPH_HDR_LENGTH((mp)->b_rptr),                  \
 117         (n) += TCP_HDR_LENGTH((tcpha_t *)&(mp)->b_rptr[(n)])
 118 
 119 /* TCP Protocol header (used if the header is known to be 32-bit aligned) */
 120 typedef struct tcphdra_s {
 121         in_port_t       tha_lport;      /* Source port */
 122         in_port_t       tha_fport;      /* Destination port */
 123         uint32_t        tha_seq;        /* Sequence number */
 124         uint32_t        tha_ack;        /* Acknowledgement number */
 125         uint8_t tha_offset_and_reserved; /* Offset to the packet data */
 126         uint8_t         tha_flags;
 127         uint16_t        tha_win;        /* Allocation number */
 128         uint16_t        tha_sum;        /* TCP checksum */
 129         uint16_t        tha_urp;        /* Urgent pointer */
 130 } tcpha_t;
 131 
 132 struct conn_s;
 133 struct tcp_listen_cnt_s;
 134 
 135 /*
 136  * Control structure for each open TCP stream,
 137  * defined only within the kernel or for a kmem user.
 138  * NOTE: tcp_reinit_values MUST have a line for each field in this structure!
 139  */
 140 #if (defined(_KERNEL) || defined(_KMEMUSER))
 141 
 142 typedef struct tcp_s {
 143         struct tcp_s    *tcp_time_wait_next;
 144                                 /* Pointer to next T/W block */
 145         struct tcp_s    *tcp_time_wait_prev;
 146                                 /* Pointer to previous T/W next */
 147         int64_t         tcp_time_wait_expire;
 148 
 149         struct conn_s   *tcp_connp;     /* back pointer to conn_t */
 150         tcp_stack_t     *tcp_tcps;      /* back pointer to tcp_stack_t */
 151 
 152         int32_t tcp_state;
 153         int32_t tcp_rcv_ws;             /* My window scale power */
 154         int32_t tcp_snd_ws;             /* Sender's window scale power */
 155         uint32_t tcp_ts_recent;         /* Timestamp of earliest unacked */
 156                                         /*  data segment */
 157         clock_t tcp_rto;                /* Round trip timeout */
 158         int64_t tcp_last_rcv_lbolt;
 159                                 /* lbolt on last packet, used for PAWS */
 160         uint32_t tcp_rto_initial;       /* Initial RTO */
 161         uint32_t tcp_rto_min;           /* Minimum RTO */
 162         uint32_t tcp_rto_max;           /* Maximum RTO */
 163 
 164         uint32_t tcp_snxt;              /* Senders next seq num */
 165         uint32_t tcp_swnd;              /* Senders window (relative to suna) */
 166         uint32_t tcp_mss;               /* Max segment size */
 167         uint32_t tcp_iss;               /* Initial send seq num */
 168         uint32_t tcp_rnxt;              /* Seq we expect to recv next */
 169         uint32_t tcp_rwnd;
 170 
 171         /* Fields arranged in approximate access order along main paths */
 172         mblk_t  *tcp_xmit_head;         /* Head of xmit/rexmit list */
 173         mblk_t  *tcp_xmit_last;         /* Last valid data seen by tcp_wput */
 174         mblk_t  *tcp_xmit_tail;         /* Last data sent */
 175         uint32_t tcp_unsent;            /* # of bytes in hand that are unsent */
 176         uint32_t tcp_xmit_tail_unsent;  /* # of unsent bytes in xmit_tail */
 177 
 178         uint32_t tcp_suna;              /* Sender unacknowledged */
 179         uint32_t tcp_rexmit_nxt;        /* Next rexmit seq num */
 180         uint32_t tcp_rexmit_max;        /* Max retran seq num */
 181         int32_t tcp_snd_burst;          /* Send burst factor */
 182         uint32_t tcp_cwnd;              /* Congestion window */
 183         int32_t tcp_cwnd_cnt;           /* cwnd cnt in congestion avoidance */
 184 
 185         uint32_t tcp_ibsegs;            /* Inbound segments on this stream */
 186         uint32_t tcp_obsegs;            /* Outbound segments on this stream */
 187 
 188         uint32_t tcp_naglim;            /* Tunable nagle limit */
 189         uint32_t        tcp_valid_bits;
 190 #define TCP_ISS_VALID   0x1     /* Is the tcp_iss seq num active? */
 191 #define TCP_FSS_VALID   0x2     /* Is the tcp_fss seq num active? */
 192 #define TCP_URG_VALID   0x4     /* Is the tcp_urg seq num active? */
 193 #define TCP_OFO_FIN_VALID 0x8   /* Has TCP received an out of order FIN? */
 194 
 195 
 196 
 197         timeout_id_t    tcp_timer_tid;  /* Control block for timer service */
 198         uchar_t tcp_timer_backoff;      /* Backoff shift count. */
 199         int64_t tcp_last_recv_time;     /* Last time we receive a segment. */
 200         uint32_t tcp_init_cwnd;         /* Initial cwnd (start/restart) */
 201 
 202         /* Following manipulated by TCP under squeue protection */
 203         uint32_t
 204                 tcp_urp_last_valid : 1, /* Is tcp_urp_last valid? */
 205                 tcp_hard_binding : 1,   /* TCP_DETACHED_NONEAGER */
 206                 tcp_fin_acked : 1,      /* Has our FIN been acked? */
 207                 tcp_fin_rcvd : 1,       /* Have we seen a FIN? */
 208 
 209                 tcp_fin_sent : 1,       /* Have we sent our FIN yet? */
 210                 tcp_ordrel_done : 1,    /* Have we sent the ord_rel upstream? */
 211                 tcp_detached : 1,       /* If we're detached from a stream */
 212                 tcp_zero_win_probe: 1,  /* Zero win probing is in progress */
 213 
 214                 tcp_loopback: 1,        /* src and dst are the same machine */
 215                 tcp_localnet: 1,        /* src and dst are on the same subnet */
 216                 tcp_syn_defense: 1,     /* For defense against SYN attack */
 217 #define tcp_dontdrop    tcp_syn_defense
 218                 tcp_set_timer : 1,
 219 
 220                 tcp_active_open: 1,     /* This is a active open */
 221                 tcp_rexmit : 1,         /* TCP is retransmitting */
 222                 tcp_snd_sack_ok : 1,    /* Can use SACK for this connection */
 223                 tcp_hwcksum : 1,        /* The NIC is capable of hwcksum */
 224 
 225                 tcp_ip_forward_progress : 1,
 226                 tcp_ecn_ok : 1,         /* Can use ECN for this connection */
 227                 tcp_ecn_echo_on : 1,    /* Need to do ECN echo */
 228                 tcp_ecn_cwr_sent : 1,   /* ECN_CWR has been sent */
 229 
 230                 tcp_cwr : 1,            /* Cwnd has reduced recently */
 231 
 232                 tcp_pad_to_bit31 : 11;
 233 
 234         /* Following manipulated by TCP under squeue protection */
 235         uint32_t
 236                 tcp_snd_ts_ok  : 1,
 237                 tcp_snd_ws_ok  : 1,
 238                 tcp_reserved_port : 1,
 239                 tcp_in_free_list : 1,
 240 
 241                 tcp_snd_zcopy_on : 1,   /* xmit zero-copy enabled */
 242                 tcp_snd_zcopy_aware : 1, /* client is zero-copy aware */
 243                 tcp_xmit_zc_clean : 1,  /* the xmit list is free of zc-mblk */
 244                 tcp_wait_for_eagers : 1, /* Wait for eagers to disappear */
 245 
 246                 tcp_accept_error : 1,   /* Error during TLI accept */
 247                 tcp_send_discon_ind : 1, /* TLI accept err, send discon ind */
 248                 tcp_cork : 1,           /* tcp_cork option */
 249                 tcp_tconnind_started : 1, /* conn_ind message is being sent */
 250 
 251                 tcp_lso :1,             /* Lower layer is capable of LSO */
 252                 tcp_is_wnd_shrnk : 1,   /* Window has shrunk */
 253 
 254                 tcp_pad_to_bit_31 : 18;
 255 
 256         uint32_t        tcp_initial_pmtu; /* Initial outgoing Path MTU. */
 257 
 258         mblk_t  *tcp_reass_head;        /* Out of order reassembly list head */
 259         mblk_t  *tcp_reass_tail;        /* Out of order reassembly list tail */
 260 
 261         /* SACK related info */
 262         tcp_sack_info_t tcp_sack_info;
 263 
 264 #define tcp_pipe                tcp_sack_info.tcp_pipe
 265 #define tcp_fack                tcp_sack_info.tcp_fack
 266 #define tcp_sack_snxt           tcp_sack_info.tcp_sack_snxt
 267 #define tcp_max_sack_blk        tcp_sack_info.tcp_max_sack_blk
 268 #define tcp_num_sack_blk        tcp_sack_info.tcp_num_sack_blk
 269 #define tcp_sack_list           tcp_sack_info.tcp_sack_list
 270 #define tcp_num_notsack_blk     tcp_sack_info.tcp_num_notsack_blk
 271 #define tcp_cnt_notsack_list    tcp_sack_info.tcp_cnt_notsack_list
 272 #define tcp_notsack_list        tcp_sack_info.tcp_notsack_list
 273 
 274         mblk_t  *tcp_rcv_list;          /* Queued until push, urgent data, */
 275         mblk_t  *tcp_rcv_last_head;     /* optdata, or the count exceeds */
 276         mblk_t  *tcp_rcv_last_tail;     /* tcp_rcv_push_wait. */
 277         uint32_t tcp_rcv_cnt;           /* tcp_rcv_list is b_next chain. */
 278 
 279         uint32_t tcp_cwnd_ssthresh;     /* Congestion window */
 280         uint32_t tcp_cwnd_max;
 281         uint32_t tcp_csuna;             /* Clear (no rexmits in window) suna */
 282 
 283         clock_t tcp_rtt_sa;             /* Round trip smoothed average */
 284         clock_t tcp_rtt_sd;             /* Round trip smoothed deviation */
 285         clock_t tcp_rtt_update;         /* Round trip update(s) */
 286         clock_t tcp_ms_we_have_waited;  /* Total retrans time */
 287 
 288         uint32_t tcp_swl1;              /* These help us avoid using stale */
 289         uint32_t tcp_swl2;              /*  packets to update state */
 290 
 291         uint32_t tcp_rack;              /* Seq # we have acked */
 292         uint32_t tcp_rack_cnt;          /* # of segs we have deferred ack */
 293         uint32_t tcp_rack_cur_max;      /* # of segs we may defer ack for now */
 294         uint32_t tcp_rack_abs_max;      /* # of segs we may defer ack ever */
 295         timeout_id_t    tcp_ack_tid;    /* Delayed ACK timer ID */
 296         timeout_id_t    tcp_push_tid;   /* Push timer ID */
 297 
 298         uint32_t tcp_max_swnd;          /* Maximum swnd we have seen */
 299 
 300         struct tcp_s *tcp_listener;     /* Our listener */
 301 
 302         uint32_t tcp_irs;               /* Initial recv seq num */
 303         uint32_t tcp_fss;               /* Final/fin send seq num */
 304         uint32_t tcp_urg;               /* Urgent data seq num */
 305 
 306         clock_t tcp_first_timer_threshold;  /* When to prod IP */
 307         clock_t tcp_second_timer_threshold; /* When to give up completely */
 308         clock_t tcp_first_ctimer_threshold; /* 1st threshold while connecting */
 309         clock_t tcp_second_ctimer_threshold; /* 2nd ... while connecting */
 310 
 311         uint32_t tcp_urp_last;          /* Last urp for which signal sent */
 312         mblk_t  *tcp_urp_mp;            /* T_EXDATA_IND for urgent byte */
 313         mblk_t  *tcp_urp_mark_mp;       /* zero-length marked/unmarked msg */
 314 
 315         int tcp_conn_req_cnt_q0;        /* # of conn reqs in SYN_RCVD */
 316         int tcp_conn_req_cnt_q; /* # of conn reqs in ESTABLISHED */
 317         int tcp_conn_req_max;   /* # of ESTABLISHED conn reqs allowed */
 318         t_scalar_t tcp_conn_req_seqnum; /* Incrementing pending conn req ID */
 319 #define tcp_ip_addr_cache       tcp_reass_tail
 320                                         /* Cache ip addresses that */
 321                                         /* complete the 3-way handshake */
 322         kmutex_t  tcp_eager_lock;
 323         struct tcp_s *tcp_eager_next_q; /* next eager in ESTABLISHED state */
 324         struct tcp_s *tcp_eager_last_q; /* last eager in ESTABLISHED state */
 325         struct tcp_s *tcp_eager_next_q0; /* next eager in SYN_RCVD state */
 326         struct tcp_s *tcp_eager_prev_q0; /* prev eager in SYN_RCVD state */
 327                                         /* all eagers form a circular list */
 328         boolean_t tcp_conn_def_q0;      /* move from q0 to q deferred */
 329 
 330         union {
 331             mblk_t *tcp_eager_conn_ind; /* T_CONN_IND waiting for 3rd ack. */
 332             mblk_t *tcp_opts_conn_req; /* T_CONN_REQ w/ options processed */
 333         } tcp_conn;
 334         uint32_t tcp_syn_rcvd_timeout;  /* How many SYN_RCVD timeout in q0 */
 335 
 336         /* TCP Keepalive Timer members */
 337         int32_t tcp_ka_last_intrvl;     /* Last probe interval */
 338         timeout_id_t tcp_ka_tid;        /* Keepalive timer ID */
 339         uint32_t tcp_ka_interval;       /* Keepalive interval */
 340         uint32_t tcp_ka_abort_thres;    /* Keepalive abort threshold */
 341 
 342         int32_t tcp_client_errno;       /* How the client screwed up */
 343 
 344         /*
 345          * The header template lives in conn_ht_iphc allocated by tcp_build_hdrs
 346          * We maintain three pointers into conn_ht_iphc.
 347          */
 348         ipha_t  *tcp_ipha;              /* IPv4 header in conn_ht_iphc */
 349         ip6_t   *tcp_ip6h;              /* IPv6 header in conn_ht_iphc */
 350         tcpha_t *tcp_tcpha;             /* TCP header in conn_ht_iphc */
 351 
 352         uint16_t tcp_last_sent_len;     /* Record length for nagle */
 353         uint16_t tcp_last_recv_len;     /* Used by DTrace */
 354         uint16_t tcp_dupack_cnt;        /* # of consequtive duplicate acks */
 355 
 356         kmutex_t        *tcp_acceptor_lockp;    /* Ptr to tf_lock */
 357 
 358         mblk_t          *tcp_ordrel_mp;         /* T_ordrel_ind mblk */
 359         t_uscalar_t     tcp_acceptor_id;        /* ACCEPTOR_id */
 360 
 361         int             tcp_ipsec_overhead;
 362 
 363         uint_t          tcp_recvifindex; /* Last received IPV6_RCVPKTINFO */
 364         uint_t          tcp_recvhops;   /* Last received IPV6_RECVHOPLIMIT */
 365         uint_t          tcp_recvtclass; /* Last received IPV6_RECVTCLASS */
 366         ip6_hbh_t       *tcp_hopopts;   /* Last received IPV6_RECVHOPOPTS */
 367         ip6_dest_t      *tcp_dstopts;   /* Last received IPV6_RECVDSTOPTS */
 368         ip6_dest_t      *tcp_rthdrdstopts; /* Last recv IPV6_RECVRTHDRDSTOPTS */
 369         ip6_rthdr_t     *tcp_rthdr;     /* Last received IPV6_RECVRTHDR */
 370         uint_t          tcp_hopoptslen;
 371         uint_t          tcp_dstoptslen;
 372         uint_t          tcp_rthdrdstoptslen;
 373         uint_t          tcp_rthdrlen;
 374 
 375         mblk_t          *tcp_timercache;
 376 
 377         kmutex_t        tcp_closelock;
 378         kcondvar_t      tcp_closecv;
 379         uint8_t         tcp_closed;
 380         uint8_t         tcp_closeflags;
 381         mblk_t          tcp_closemp;
 382         timeout_id_t    tcp_linger_tid; /* Linger timer ID */
 383 
 384         struct tcp_s *tcp_acceptor_hash; /* Acceptor hash chain */
 385         struct tcp_s **tcp_ptpahn; /* Pointer to previous accept hash next. */
 386         struct tcp_s *tcp_bind_hash; /* Bind hash chain */
 387         struct tcp_s *tcp_bind_hash_port; /* tcp_t's bound to the same lport */
 388         struct tcp_s **tcp_ptpbhn;
 389 
 390         uint_t          tcp_maxpsz_multiplier;
 391 
 392         uint32_t        tcp_lso_max; /* maximum LSO payload */
 393 
 394         uint32_t        tcp_ofo_fin_seq; /* Recv out of order FIN seq num */
 395         uint32_t        tcp_cwr_snd_max;
 396 
 397         struct tcp_s *tcp_saved_listener;       /* saved value of listener */
 398 
 399         uint32_t        tcp_in_ack_unsent;      /* ACK for unsent data cnt. */
 400 
 401         /*
 402          * All fusion-related fields are protected by squeue.
 403          */
 404         struct tcp_s *tcp_loopback_peer;        /* peer tcp for loopback */
 405         mblk_t  *tcp_fused_sigurg_mp;           /* M_PCSIG mblk for SIGURG */
 406 
 407         uint32_t
 408                 tcp_fused : 1,          /* loopback tcp in fusion mode */
 409                 tcp_unfusable : 1,      /* fusion not allowed on endpoint */
 410                 tcp_fused_sigurg : 1,   /* send SIGURG upon draining */
 411 
 412                 tcp_fuse_to_bit_31 : 29;
 413 
 414         kmutex_t tcp_non_sq_lock;
 415 
 416         /*
 417          * This variable is accessed without any lock protection
 418          * and therefore must not be declared as a bit field along
 419          * with the rest which require such condition.
 420          */
 421         boolean_t       tcp_issocket;   /* this is a socket tcp */
 422 
 423         /* protected by the tcp_non_sq_lock lock */
 424         uint32_t        tcp_squeue_bytes;
 425 
 426         /*
 427          * tcp_closemp_used is protected by listener's tcp_eager_lock
 428          * when used for eagers. When used for a tcp in TIME_WAIT state
 429          * or in tcp_close(), it is not protected by any lock as we
 430          * do not expect any other thread to use it concurrently.
 431          * We do allow re-use of tcp_closemp in tcp_time_wait_collector()
 432          * and tcp_close() but not concurrently.
 433          */
 434         boolean_t tcp_closemp_used;
 435 
 436         /*
 437          * previous and next eagers in the list of droppable eagers. See
 438          * the comments before MAKE_DROPPABLE(). These pointers are
 439          * protected by listener's tcp_eager_lock.
 440          */
 441         struct tcp_s    *tcp_eager_prev_drop_q0;
 442         struct tcp_s    *tcp_eager_next_drop_q0;
 443 
 444         /*
 445          * Have we flow controlled xmitter?
 446          * This variable can be modified outside the squeue and hence must
 447          * not be declared as a bit field along with the rest that are
 448          * modified only within the squeue.
 449          * protected by the tcp_non_sq_lock lock.
 450          */
 451         boolean_t       tcp_flow_stopped;
 452 
 453         /*
 454          * Sender's next sequence number at the time the window was shrunk.
 455          */
 456         uint32_t        tcp_snxt_shrunk;
 457 
 458         /*
 459          * Socket generation number which is bumped when a connection attempt
 460          * is initiated. Its main purpose is to ensure that the socket does not
 461          * miss the asynchronous connected/disconnected notification.
 462          */
 463         sock_connid_t   tcp_connid;
 464 
 465         /* mblk_t used to enter TCP's squeue from the service routine. */
 466         mblk_t          *tcp_rsrv_mp;
 467         /* Mutex for accessing tcp_rsrv_mp */
 468         kmutex_t        tcp_rsrv_mp_lock;
 469 
 470         /* For connection counting. */
 471         struct tcp_listen_cnt_s *tcp_listen_cnt;
 472 
 473         /* Segment reassembly timer. */
 474         timeout_id_t            tcp_reass_tid;
 475 
 476         /* FIN-WAIT-2 flush timeout */
 477         uint32_t                tcp_fin_wait_2_flush_interval;
 478 
 479 #ifdef DEBUG
 480         pc_t                    tcmp_stk[15];
 481 #endif
 482 } tcp_t;
 483 
 484 #ifdef DEBUG
 485 #define TCP_DEBUG_GETPCSTACK(buffer, depth)     ((void) getpcstack(buffer, \
 486                                                     depth))
 487 #else
 488 #define TCP_DEBUG_GETPCSTACK(buffer, depth)
 489 #endif
 490 
 491 extern void     tcp_conn_reclaim(void *);
 492 extern void     tcp_free(tcp_t *tcp);
 493 extern void     tcp_ddi_g_init(void);
 494 extern void     tcp_ddi_g_destroy(void);
 495 extern void     *tcp_get_conn(void *arg, tcp_stack_t *);
 496 extern mblk_t   *tcp_snmp_get(queue_t *, mblk_t *, boolean_t);
 497 extern int      tcp_snmp_set(queue_t *, int, int, uchar_t *, int len);
 498 
 499 /*
 500  * The TCP Fanout structure for bind and acceptor hashes.
 501  * The hash tables and their linkage (tcp_*_hash, tcp_ptp*hn) are
 502  * protected by the per-bucket tf_lock.  Each tcp_t
 503  * inserted in the list points back at this lock using tcp_*_lockp.
 504  *
 505  * The bind and acceptor hash queues are lists of tcp_t.
 506  */
 507 /* listener hash and acceptor hash queue head */
 508 typedef struct tf_s {
 509         tcp_t           *tf_tcp;
 510         kmutex_t        tf_lock;
 511 } tf_t;
 512 
 513 
 514 /* Also used in ipclassifier.c */
 515 extern struct kmem_cache  *tcp_sack_info_cache;
 516 
 517 #endif  /* (defined(_KERNEL) || defined(_KMEMUSER)) */
 518 
 519 /* Contract private interface between TCP and Clustering. */
 520 
 521 #define CL_TCPI_V1      1       /* cl_tcpi_version number */
 522 
 523 typedef struct cl_tcp_info_s {
 524         ushort_t        cl_tcpi_version;        /* cl_tcp_info_t's version no */
 525         ushort_t        cl_tcpi_ipversion;      /* IP version */
 526         int32_t         cl_tcpi_state;          /* TCP state */
 527         in_port_t       cl_tcpi_lport;          /* Local port */
 528         in_port_t       cl_tcpi_fport;          /* Remote port */
 529         in6_addr_t      cl_tcpi_laddr_v6;       /* Local IP address */
 530         in6_addr_t      cl_tcpi_faddr_v6;       /* Remote IP address */
 531 #ifdef _KERNEL
 532 /* Note: V4_PART_OF_V6 is meant to be used only for _KERNEL defined stuff */
 533 #define cl_tcpi_laddr   V4_PART_OF_V6(cl_tcpi_laddr_v6)
 534 #define cl_tcpi_faddr   V4_PART_OF_V6(cl_tcpi_faddr_v6)
 535 
 536 #endif  /* _KERNEL */
 537 } cl_tcp_info_t;
 538 
 539 /*
 540  * Hook functions to enable cluster networking
 541  * On non-clustered systems these vectors must always be NULL.
 542  */
 543 extern void     (*cl_inet_listen)(netstackid_t, uint8_t, sa_family_t,
 544                     uint8_t *, in_port_t, void *);
 545 extern void     (*cl_inet_unlisten)(netstackid_t, uint8_t, sa_family_t,
 546                     uint8_t *, in_port_t, void *);
 547 
 548 /*
 549  * Contracted Consolidation Private ioctl for aborting TCP connections.
 550  * In order to keep the offsets and size of the structure the same between
 551  * a 32-bit application and a 64-bit amd64 kernel, we use a #pragma
 552  * pack(4).
 553  */
 554 #define TCP_IOC_ABORT_CONN      (('T' << 8) + 91)
 555 
 556 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 557 #pragma pack(4)
 558 #endif
 559 
 560 typedef struct tcp_ioc_abort_conn_s {
 561         struct sockaddr_storage ac_local;       /* local addr and port */
 562         struct sockaddr_storage ac_remote;      /* remote addr and port */
 563         int32_t ac_start;                       /* start state */
 564         int32_t ac_end;                         /* end state  */
 565         int32_t ac_zoneid;                      /* zoneid */
 566 } tcp_ioc_abort_conn_t;
 567 
 568 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 569 #pragma pack()
 570 #endif
 571 
 572 #ifdef  __cplusplus
 573 }
 574 #endif
 575 
 576 #endif  /* _INET_TCP_H */