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  * Copyright (c) 2011, Joyent, Inc. All rights reserved.
  24  */
  25 /* Copyright (c) 1990 Mentat Inc. */
  26 
  27 #ifndef _INET_TCP_H
  28 #define _INET_TCP_H
  29 
  30 #ifdef  __cplusplus
  31 extern "C" {
  32 #endif
  33 
  34 #include <sys/inttypes.h>
  35 #include <netinet/ip6.h>
  36 #include <netinet/tcp.h>
  37 #include <sys/socket.h>
  38 #include <sys/socket_proto.h>
  39 #include <sys/md5.h>
  40 #include <inet/common.h>
  41 #include <inet/ip.h>
  42 #include <inet/ip6.h>
  43 #include <inet/mi.h>
  44 #include <inet/mib2.h>
  45 #include <inet/tcp_stack.h>
  46 #include <inet/tcp_sack.h>
  47 
  48 /* TCP states */
  49 #define TCPS_CLOSED             -6
  50 #define TCPS_IDLE               -5      /* idle (opened, but not bound) */
  51 #define TCPS_BOUND              -4      /* bound, ready to connect or accept */
  52 #define TCPS_LISTEN             -3      /* listening for connection */
  53 #define TCPS_SYN_SENT           -2      /* active, have sent syn */
  54 #define TCPS_SYN_RCVD           -1      /* have received syn (and sent ours) */
  55 /* states < TCPS_ESTABLISHED are those where connections not established */
  56 #define TCPS_ESTABLISHED        0       /* established */
  57 #define TCPS_CLOSE_WAIT         1       /* rcvd fin, waiting for close */
  58 /* states > TCPS_CLOSE_WAIT are those where user has closed */
  59 #define TCPS_FIN_WAIT_1         2       /* have closed and sent fin */
  60 #define TCPS_CLOSING            3       /* closed, xchd FIN, await FIN ACK */
  61 #define TCPS_LAST_ACK           4       /* had fin and close; await FIN ACK */
  62 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
  63 #define TCPS_FIN_WAIT_2         5       /* have closed, fin is acked */
  64 #define TCPS_TIME_WAIT          6       /* in 2*msl quiet wait after close */
  65 
  66 /*
  67  * Internal flags used in conjunction with the packet header flags.
  68  * Used in tcp_input_data to keep track of what needs to be done.
  69  */
  70 #define TH_LIMIT_XMIT           0x0400  /* Limited xmit is needed */
  71 #define TH_XMIT_NEEDED          0x0800  /* Window opened - send queued data */
  72 #define TH_REXMIT_NEEDED        0x1000  /* Time expired for unacked data */
  73 #define TH_ACK_NEEDED           0x2000  /* Send an ack now. */
  74 #define TH_NEED_SACK_REXMIT     0x4000  /* Use SACK info to retransmission */
  75 #define TH_ACK_TIMER_NEEDED     0x8000  /* Start the delayed ACK timer */
  76 #define TH_ORDREL_NEEDED        0x10000 /* Generate an ordrel indication */
  77 #define TH_MARKNEXT_NEEDED      0x20000 /* Data should have MSGMARKNEXT */
  78 #define TH_SEND_URP_MARK        0x40000 /* Send up tcp_urp_mark_mp */
  79 
  80 /*
  81  * TCP sequence numbers are 32 bit integers operated
  82  * on with modular arithmetic.  These macros can be
  83  * used to compare such integers.
  84  */
  85 #define SEQ_LT(a, b)    ((int32_t)((a)-(b)) < 0)
  86 #define SEQ_LEQ(a, b)   ((int32_t)((a)-(b)) <= 0)
  87 #define SEQ_GT(a, b)    ((int32_t)((a)-(b)) > 0)
  88 #define SEQ_GEQ(a, b)   ((int32_t)((a)-(b)) >= 0)
  89 
  90 /* TCP Protocol header */
  91 typedef struct tcphdr_s {
  92         uint8_t         th_lport[2];    /* Source port */
  93         uint8_t         th_fport[2];    /* Destination port */
  94         uint8_t         th_seq[4];      /* Sequence number */
  95         uint8_t         th_ack[4];      /* Acknowledgement number */
  96         uint8_t         th_offset_and_rsrvd[1]; /* Offset to the packet data */
  97         uint8_t         th_flags[1];
  98         uint8_t         th_win[2];      /* Allocation number */
  99         uint8_t         th_sum[2];      /* TCP checksum */
 100         uint8_t         th_urp[2];      /* Urgent pointer */
 101 } tcph_t;
 102 
 103 #define TCP_HDR_LENGTH(tcph) \
 104         ((((tcph_t *)tcph)->th_offset_and_rsrvd[0] >>2) &(0xF << 2))
 105 #define TCP_MAX_COMBINED_HEADER_LENGTH  (60 + 60) /* Maxed out ip + tcp */
 106 #define TCP_MAX_IP_OPTIONS_LENGTH       (60 - IP_SIMPLE_HDR_LENGTH)
 107 #define TCP_MAX_HDR_LENGTH              60
 108 #define TCP_MAX_TCP_OPTIONS_LENGTH      (60 - sizeof (tcpha_t))
 109 #define TCP_MIN_HEADER_LENGTH           20
 110 #define TCP_MAXWIN                      65535
 111 #define TCP_PORT_LEN                    sizeof (in_port_t)
 112 #define TCP_MAX_WINSHIFT                14
 113 #define TCP_MAX_LARGEWIN                (TCP_MAXWIN << TCP_MAX_WINSHIFT)
 114 #define TCP_MAX_LSO_LENGTH      (IP_MAXPACKET - TCP_MAX_COMBINED_HEADER_LENGTH)
 115 
 116 #define TCPIP_HDR_LENGTH(mp, n)                                 \
 117         (n) = IPH_HDR_LENGTH((mp)->b_rptr),                  \
 118         (n) += TCP_HDR_LENGTH((tcpha_t *)&(mp)->b_rptr[(n)])
 119 
 120 /* TCP Protocol header (used if the header is known to be 32-bit aligned) */
 121 typedef struct tcphdra_s {
 122         in_port_t       tha_lport;      /* Source port */
 123         in_port_t       tha_fport;      /* Destination port */
 124         uint32_t        tha_seq;        /* Sequence number */
 125         uint32_t        tha_ack;        /* Acknowledgement number */
 126         uint8_t tha_offset_and_reserved; /* Offset to the packet data */
 127         uint8_t         tha_flags;
 128         uint16_t        tha_win;        /* Allocation number */
 129         uint16_t        tha_sum;        /* TCP checksum */
 130         uint16_t        tha_urp;        /* Urgent pointer */
 131 } tcpha_t;
 132 
 133 struct conn_s;
 134 struct tcp_listen_cnt_s;
 135 
 136 /*
 137  * Control structure for each open TCP stream,
 138  * defined only within the kernel or for a kmem user.
 139  * NOTE: tcp_reinit_values MUST have a line for each field in this structure!
 140  */
 141 #if (defined(_KERNEL) || defined(_KMEMUSER))
 142 
 143 typedef struct tcp_s {
 144         struct tcp_s    *tcp_time_wait_next;
 145                                 /* Pointer to next T/W block */
 146         struct tcp_s    *tcp_time_wait_prev;
 147                                 /* Pointer to previous T/W next */
 148         int64_t         tcp_time_wait_expire;
 149 
 150         struct conn_s   *tcp_connp;     /* back pointer to conn_t */
 151         tcp_stack_t     *tcp_tcps;      /* back pointer to tcp_stack_t */
 152 
 153         int32_t tcp_state;
 154         int32_t tcp_rcv_ws;             /* My window scale power */
 155         int32_t tcp_snd_ws;             /* Sender's window scale power */
 156         uint32_t tcp_ts_recent;         /* Timestamp of earliest unacked */
 157                                         /*  data segment */
 158         clock_t tcp_rto;                /* Round trip timeout */
 159         int64_t tcp_last_rcv_lbolt;
 160                                 /* lbolt on last packet, used for PAWS */
 161         uint32_t tcp_rto_initial;       /* Initial RTO */
 162         uint32_t tcp_rto_min;           /* Minimum RTO */
 163         uint32_t tcp_rto_max;           /* Maximum RTO */
 164 
 165         uint32_t tcp_snxt;              /* Senders next seq num */
 166         uint32_t tcp_swnd;              /* Senders window (relative to suna) */
 167         uint32_t tcp_mss;               /* Max segment size */
 168         uint32_t tcp_iss;               /* Initial send seq num */
 169         uint32_t tcp_rnxt;              /* Seq we expect to recv next */
 170         uint32_t tcp_rwnd;
 171 
 172         /* Fields arranged in approximate access order along main paths */
 173         mblk_t  *tcp_xmit_head;         /* Head of xmit/rexmit list */
 174         mblk_t  *tcp_xmit_last;         /* Last valid data seen by tcp_wput */
 175         mblk_t  *tcp_xmit_tail;         /* Last data sent */
 176         uint32_t tcp_unsent;            /* # of bytes in hand that are unsent */
 177         uint32_t tcp_xmit_tail_unsent;  /* # of unsent bytes in xmit_tail */
 178 
 179         uint32_t tcp_suna;              /* Sender unacknowledged */
 180         uint32_t tcp_rexmit_nxt;        /* Next rexmit seq num */
 181         uint32_t tcp_rexmit_max;        /* Max retran seq num */
 182         int32_t tcp_snd_burst;          /* Send burst factor */
 183         uint32_t tcp_cwnd;              /* Congestion window */
 184         int32_t tcp_cwnd_cnt;           /* cwnd cnt in congestion avoidance */
 185 
 186         uint32_t tcp_ibsegs;            /* Inbound segments on this stream */
 187         uint32_t tcp_obsegs;            /* Outbound segments on this stream */
 188 
 189         uint32_t tcp_naglim;            /* Tunable nagle limit */
 190         uint32_t        tcp_valid_bits;
 191 #define TCP_ISS_VALID   0x1     /* Is the tcp_iss seq num active? */
 192 #define TCP_FSS_VALID   0x2     /* Is the tcp_fss seq num active? */
 193 #define TCP_URG_VALID   0x4     /* Is the tcp_urg seq num active? */
 194 #define TCP_OFO_FIN_VALID 0x8   /* Has TCP received an out of order FIN? */
 195 
 196 
 197 
 198         timeout_id_t    tcp_timer_tid;  /* Control block for timer service */
 199         uchar_t tcp_timer_backoff;      /* Backoff shift count. */
 200         int64_t tcp_last_recv_time;     /* Last time we receive a segment. */
 201         uint32_t tcp_init_cwnd;         /* Initial cwnd (start/restart) */
 202 
 203         /* Following manipulated by TCP under squeue protection */
 204         uint32_t
 205                 tcp_urp_last_valid : 1, /* Is tcp_urp_last valid? */
 206                 tcp_hard_binding : 1,   /* TCP_DETACHED_NONEAGER */
 207                 tcp_fin_acked : 1,      /* Has our FIN been acked? */
 208                 tcp_fin_rcvd : 1,       /* Have we seen a FIN? */
 209 
 210                 tcp_fin_sent : 1,       /* Have we sent our FIN yet? */
 211                 tcp_ordrel_done : 1,    /* Have we sent the ord_rel upstream? */
 212                 tcp_detached : 1,       /* If we're detached from a stream */
 213                 tcp_zero_win_probe: 1,  /* Zero win probing is in progress */
 214 
 215                 tcp_loopback: 1,        /* src and dst are the same machine */
 216                 tcp_localnet: 1,        /* src and dst are on the same subnet */
 217                 tcp_syn_defense: 1,     /* For defense against SYN attack */
 218 #define tcp_dontdrop    tcp_syn_defense
 219                 tcp_set_timer : 1,
 220 
 221                 tcp_active_open: 1,     /* This is a active open */
 222                 tcp_rexmit : 1,         /* TCP is retransmitting */
 223                 tcp_snd_sack_ok : 1,    /* Can use SACK for this connection */
 224                 tcp_hwcksum : 1,        /* The NIC is capable of hwcksum */
 225 
 226                 tcp_ip_forward_progress : 1,
 227                 tcp_ecn_ok : 1,         /* Can use ECN for this connection */
 228                 tcp_ecn_echo_on : 1,    /* Need to do ECN echo */
 229                 tcp_ecn_cwr_sent : 1,   /* ECN_CWR has been sent */
 230 
 231                 tcp_cwr : 1,            /* Cwnd has reduced recently */
 232 
 233                 tcp_pad_to_bit31 : 11;
 234 
 235         /* Following manipulated by TCP under squeue protection */
 236         uint32_t
 237                 tcp_snd_ts_ok  : 1,
 238                 tcp_snd_ws_ok  : 1,
 239                 tcp_reserved_port : 1,
 240                 tcp_in_free_list : 1,
 241 
 242                 tcp_snd_zcopy_on : 1,   /* xmit zero-copy enabled */
 243                 tcp_snd_zcopy_aware : 1, /* client is zero-copy aware */
 244                 tcp_xmit_zc_clean : 1,  /* the xmit list is free of zc-mblk */
 245                 tcp_wait_for_eagers : 1, /* Wait for eagers to disappear */
 246 
 247                 tcp_accept_error : 1,   /* Error during TLI accept */
 248                 tcp_send_discon_ind : 1, /* TLI accept err, send discon ind */
 249                 tcp_cork : 1,           /* tcp_cork option */
 250                 tcp_tconnind_started : 1, /* conn_ind message is being sent */
 251 
 252                 tcp_lso :1,             /* Lower layer is capable of LSO */
 253                 tcp_is_wnd_shrnk : 1,   /* Window has shrunk */
 254 
 255                 tcp_pad_to_bit_31 : 18;
 256 
 257         uint32_t        tcp_initial_pmtu; /* Initial outgoing Path MTU. */
 258 
 259         mblk_t  *tcp_reass_head;        /* Out of order reassembly list head */
 260         mblk_t  *tcp_reass_tail;        /* Out of order reassembly list tail */
 261 
 262         /* SACK related info */
 263         tcp_sack_info_t tcp_sack_info;
 264 
 265 #define tcp_pipe                tcp_sack_info.tcp_pipe
 266 #define tcp_fack                tcp_sack_info.tcp_fack
 267 #define tcp_sack_snxt           tcp_sack_info.tcp_sack_snxt
 268 #define tcp_max_sack_blk        tcp_sack_info.tcp_max_sack_blk
 269 #define tcp_num_sack_blk        tcp_sack_info.tcp_num_sack_blk
 270 #define tcp_sack_list           tcp_sack_info.tcp_sack_list
 271 #define tcp_num_notsack_blk     tcp_sack_info.tcp_num_notsack_blk
 272 #define tcp_cnt_notsack_list    tcp_sack_info.tcp_cnt_notsack_list
 273 #define tcp_notsack_list        tcp_sack_info.tcp_notsack_list
 274 
 275         mblk_t  *tcp_rcv_list;          /* Queued until push, urgent data, */
 276         mblk_t  *tcp_rcv_last_head;     /* optdata, or the count exceeds */
 277         mblk_t  *tcp_rcv_last_tail;     /* tcp_rcv_push_wait. */
 278         uint32_t tcp_rcv_cnt;           /* tcp_rcv_list is b_next chain. */
 279 
 280         uint32_t tcp_cwnd_ssthresh;     /* Congestion window */
 281         uint32_t tcp_cwnd_max;
 282         uint32_t tcp_csuna;             /* Clear (no rexmits in window) suna */
 283 
 284         clock_t tcp_rtt_sa;             /* Round trip smoothed average */
 285         clock_t tcp_rtt_sd;             /* Round trip smoothed deviation */
 286         clock_t tcp_rtt_update;         /* Round trip update(s) */
 287         clock_t tcp_ms_we_have_waited;  /* Total retrans time */
 288 
 289         uint32_t tcp_swl1;              /* These help us avoid using stale */
 290         uint32_t tcp_swl2;              /*  packets to update state */
 291 
 292         uint32_t tcp_rack;              /* Seq # we have acked */
 293         uint32_t tcp_rack_cnt;          /* # of segs we have deferred ack */
 294         uint32_t tcp_rack_cur_max;      /* # of segs we may defer ack for now */
 295         uint32_t tcp_rack_abs_max;      /* # of segs we may defer ack ever */
 296         timeout_id_t    tcp_ack_tid;    /* Delayed ACK timer ID */
 297         timeout_id_t    tcp_push_tid;   /* Push timer ID */
 298 
 299         uint32_t tcp_max_swnd;          /* Maximum swnd we have seen */
 300 
 301         struct tcp_s *tcp_listener;     /* Our listener */
 302 
 303         uint32_t tcp_irs;               /* Initial recv seq num */
 304         uint32_t tcp_fss;               /* Final/fin send seq num */
 305         uint32_t tcp_urg;               /* Urgent data seq num */
 306 
 307         clock_t tcp_first_timer_threshold;  /* When to prod IP */
 308         clock_t tcp_second_timer_threshold; /* When to give up completely */
 309         clock_t tcp_first_ctimer_threshold; /* 1st threshold while connecting */
 310         clock_t tcp_second_ctimer_threshold; /* 2nd ... while connecting */
 311 
 312         uint32_t tcp_urp_last;          /* Last urp for which signal sent */
 313         mblk_t  *tcp_urp_mp;            /* T_EXDATA_IND for urgent byte */
 314         mblk_t  *tcp_urp_mark_mp;       /* zero-length marked/unmarked msg */
 315 
 316         int tcp_conn_req_cnt_q0;        /* # of conn reqs in SYN_RCVD */
 317         int tcp_conn_req_cnt_q; /* # of conn reqs in ESTABLISHED */
 318         int tcp_conn_req_max;   /* # of ESTABLISHED conn reqs allowed */
 319         t_scalar_t tcp_conn_req_seqnum; /* Incrementing pending conn req ID */
 320 #define tcp_ip_addr_cache       tcp_reass_tail
 321                                         /* Cache ip addresses that */
 322                                         /* complete the 3-way handshake */
 323         kmutex_t  tcp_eager_lock;
 324         struct tcp_s *tcp_eager_next_q; /* next eager in ESTABLISHED state */
 325         struct tcp_s *tcp_eager_last_q; /* last eager in ESTABLISHED state */
 326         struct tcp_s *tcp_eager_next_q0; /* next eager in SYN_RCVD state */
 327         struct tcp_s *tcp_eager_prev_q0; /* prev eager in SYN_RCVD state */
 328                                         /* all eagers form a circular list */
 329         boolean_t tcp_conn_def_q0;      /* move from q0 to q deferred */
 330 
 331         union {
 332             mblk_t *tcp_eager_conn_ind; /* T_CONN_IND waiting for 3rd ack. */
 333             mblk_t *tcp_opts_conn_req; /* T_CONN_REQ w/ options processed */
 334         } tcp_conn;
 335         uint32_t tcp_syn_rcvd_timeout;  /* How many SYN_RCVD timeout in q0 */
 336 
 337         /* TCP Keepalive Timer members */
 338         int32_t tcp_ka_last_intrvl;     /* Last probe interval */
 339         timeout_id_t tcp_ka_tid;        /* Keepalive timer ID */
 340         uint32_t tcp_ka_interval;       /* Keepalive interval */
 341         uint32_t tcp_ka_abort_thres;    /* Keepalive abort threshold */
 342 
 343         int32_t tcp_client_errno;       /* How the client screwed up */
 344 
 345         /*
 346          * The header template lives in conn_ht_iphc allocated by tcp_build_hdrs
 347          * We maintain three pointers into conn_ht_iphc.
 348          */
 349         ipha_t  *tcp_ipha;              /* IPv4 header in conn_ht_iphc */
 350         ip6_t   *tcp_ip6h;              /* IPv6 header in conn_ht_iphc */
 351         tcpha_t *tcp_tcpha;             /* TCP header in conn_ht_iphc */
 352 
 353         uint16_t tcp_last_sent_len;     /* Record length for nagle */
 354         uint16_t tcp_last_recv_len;     /* Used by DTrace */
 355         uint16_t tcp_dupack_cnt;        /* # of consequtive duplicate acks */
 356 
 357         kmutex_t        *tcp_acceptor_lockp;    /* Ptr to tf_lock */
 358 
 359         mblk_t          *tcp_ordrel_mp;         /* T_ordrel_ind mblk */
 360         t_uscalar_t     tcp_acceptor_id;        /* ACCEPTOR_id */
 361 
 362         int             tcp_ipsec_overhead;
 363 
 364         uint_t          tcp_recvifindex; /* Last received IPV6_RCVPKTINFO */
 365         uint_t          tcp_recvhops;   /* Last received IPV6_RECVHOPLIMIT */
 366         uint_t          tcp_recvtclass; /* Last received IPV6_RECVTCLASS */
 367         ip6_hbh_t       *tcp_hopopts;   /* Last received IPV6_RECVHOPOPTS */
 368         ip6_dest_t      *tcp_dstopts;   /* Last received IPV6_RECVDSTOPTS */
 369         ip6_dest_t      *tcp_rthdrdstopts; /* Last recv IPV6_RECVRTHDRDSTOPTS */
 370         ip6_rthdr_t     *tcp_rthdr;     /* Last received IPV6_RECVRTHDR */
 371         uint_t          tcp_hopoptslen;
 372         uint_t          tcp_dstoptslen;
 373         uint_t          tcp_rthdrdstoptslen;
 374         uint_t          tcp_rthdrlen;
 375 
 376         mblk_t          *tcp_timercache;
 377 
 378         kmutex_t        tcp_closelock;
 379         kcondvar_t      tcp_closecv;
 380         uint8_t         tcp_closed;
 381         uint8_t         tcp_closeflags;
 382         mblk_t          tcp_closemp;
 383         timeout_id_t    tcp_linger_tid; /* Linger timer ID */
 384 
 385         struct tcp_s *tcp_acceptor_hash; /* Acceptor hash chain */
 386         struct tcp_s **tcp_ptpahn; /* Pointer to previous accept hash next. */
 387         struct tcp_s *tcp_bind_hash; /* Bind hash chain */
 388         struct tcp_s *tcp_bind_hash_port; /* tcp_t's bound to the same lport */
 389         struct tcp_s **tcp_ptpbhn;
 390 
 391         uint_t          tcp_maxpsz_multiplier;
 392 
 393         uint32_t        tcp_lso_max; /* maximum LSO payload */
 394 
 395         uint32_t        tcp_ofo_fin_seq; /* Recv out of order FIN seq num */
 396         uint32_t        tcp_cwr_snd_max;
 397 
 398         struct tcp_s *tcp_saved_listener;       /* saved value of listener */
 399 
 400         uint32_t        tcp_in_ack_unsent;      /* ACK for unsent data cnt. */
 401 
 402         /*
 403          * All fusion-related fields are protected by squeue.
 404          */
 405         struct tcp_s *tcp_loopback_peer;        /* peer tcp for loopback */
 406         mblk_t  *tcp_fused_sigurg_mp;           /* M_PCSIG mblk for SIGURG */
 407 
 408         uint32_t
 409                 tcp_fused : 1,          /* loopback tcp in fusion mode */
 410                 tcp_unfusable : 1,      /* fusion not allowed on endpoint */
 411                 tcp_fused_sigurg : 1,   /* send SIGURG upon draining */
 412 
 413                 tcp_fuse_to_bit_31 : 29;
 414 
 415         kmutex_t tcp_non_sq_lock;
 416 
 417         /*
 418          * This variable is accessed without any lock protection
 419          * and therefore must not be declared as a bit field along
 420          * with the rest which require such condition.
 421          */
 422         boolean_t       tcp_issocket;   /* this is a socket tcp */
 423 
 424         /* protected by the tcp_non_sq_lock lock */
 425         uint32_t        tcp_squeue_bytes;
 426 
 427         /*
 428          * tcp_closemp_used is protected by listener's tcp_eager_lock
 429          * when used for eagers. When used for a tcp in TIME_WAIT state
 430          * or in tcp_close(), it is not protected by any lock as we
 431          * do not expect any other thread to use it concurrently.
 432          * We do allow re-use of tcp_closemp in tcp_time_wait_collector()
 433          * and tcp_close() but not concurrently.
 434          */
 435         boolean_t tcp_closemp_used;
 436 
 437         /*
 438          * previous and next eagers in the list of droppable eagers. See
 439          * the comments before MAKE_DROPPABLE(). These pointers are
 440          * protected by listener's tcp_eager_lock.
 441          */
 442         struct tcp_s    *tcp_eager_prev_drop_q0;
 443         struct tcp_s    *tcp_eager_next_drop_q0;
 444 
 445         /*
 446          * Have we flow controlled xmitter?
 447          * This variable can be modified outside the squeue and hence must
 448          * not be declared as a bit field along with the rest that are
 449          * modified only within the squeue.
 450          * protected by the tcp_non_sq_lock lock.
 451          */
 452         boolean_t       tcp_flow_stopped;
 453 
 454         /*
 455          * Sender's next sequence number at the time the window was shrunk.
 456          */
 457         uint32_t        tcp_snxt_shrunk;
 458 
 459         /*
 460          * Socket generation number which is bumped when a connection attempt
 461          * is initiated. Its main purpose is to ensure that the socket does not
 462          * miss the asynchronous connected/disconnected notification.
 463          */
 464         sock_connid_t   tcp_connid;
 465 
 466         /* mblk_t used to enter TCP's squeue from the service routine. */
 467         mblk_t          *tcp_rsrv_mp;
 468         /* Mutex for accessing tcp_rsrv_mp */
 469         kmutex_t        tcp_rsrv_mp_lock;
 470 
 471         /* For connection counting. */
 472         struct tcp_listen_cnt_s *tcp_listen_cnt;
 473 
 474         /* Segment reassembly timer. */
 475         timeout_id_t            tcp_reass_tid;
 476 
 477         /* FIN-WAIT-2 flush timeout */
 478         uint32_t                tcp_fin_wait_2_flush_interval;
 479 
 480 #ifdef DEBUG
 481         pc_t                    tcmp_stk[15];
 482 #endif
 483 } tcp_t;
 484 
 485 #ifdef DEBUG
 486 #define TCP_DEBUG_GETPCSTACK(buffer, depth)     ((void) getpcstack(buffer, \
 487                                                     depth))
 488 #else
 489 #define TCP_DEBUG_GETPCSTACK(buffer, depth)
 490 #endif
 491 
 492 extern void     tcp_conn_reclaim(void *);
 493 extern void     tcp_free(tcp_t *tcp);
 494 extern void     tcp_ddi_g_init(void);
 495 extern void     tcp_ddi_g_destroy(void);
 496 extern void     *tcp_get_conn(void *arg, tcp_stack_t *);
 497 extern mblk_t   *tcp_snmp_get(queue_t *, mblk_t *, boolean_t);
 498 extern int      tcp_snmp_set(queue_t *, int, int, uchar_t *, int len);
 499 
 500 /* Pad for the tf_t structure to avoid false cache line sharing. */
 501 #define TF_CACHEL_PAD   64
 502 
 503 /*
 504  * The TCP Fanout structure for bind and acceptor hashes.
 505  * The hash tables and their linkage (tcp_*_hash, tcp_ptp*hn) are
 506  * protected by the per-bucket tf_lock.  Each tcp_t
 507  * inserted in the list points back at this lock using tcp_*_lockp.
 508  *
 509  * The bind and acceptor hash queues are lists of tcp_t.
 510  */
 511 /* listener hash and acceptor hash queue head */
 512 typedef struct tf_s {
 513         tcp_t           *tf_tcp;
 514         kmutex_t        tf_lock;
 515         unsigned char   tf_pad[TF_CACHEL_PAD -
 516             (sizeof (tcp_t *) + sizeof (kmutex_t))];
 517 } tf_t;
 518 
 519 
 520 /* Also used in ipclassifier.c */
 521 extern struct kmem_cache  *tcp_sack_info_cache;
 522 
 523 #endif  /* (defined(_KERNEL) || defined(_KMEMUSER)) */
 524 
 525 /* Contract private interface between TCP and Clustering. */
 526 
 527 #define CL_TCPI_V1      1       /* cl_tcpi_version number */
 528 
 529 typedef struct cl_tcp_info_s {
 530         ushort_t        cl_tcpi_version;        /* cl_tcp_info_t's version no */
 531         ushort_t        cl_tcpi_ipversion;      /* IP version */
 532         int32_t         cl_tcpi_state;          /* TCP state */
 533         in_port_t       cl_tcpi_lport;          /* Local port */
 534         in_port_t       cl_tcpi_fport;          /* Remote port */
 535         in6_addr_t      cl_tcpi_laddr_v6;       /* Local IP address */
 536         in6_addr_t      cl_tcpi_faddr_v6;       /* Remote IP address */
 537 #ifdef _KERNEL
 538 /* Note: V4_PART_OF_V6 is meant to be used only for _KERNEL defined stuff */
 539 #define cl_tcpi_laddr   V4_PART_OF_V6(cl_tcpi_laddr_v6)
 540 #define cl_tcpi_faddr   V4_PART_OF_V6(cl_tcpi_faddr_v6)
 541 
 542 #endif  /* _KERNEL */
 543 } cl_tcp_info_t;
 544 
 545 /*
 546  * Hook functions to enable cluster networking
 547  * On non-clustered systems these vectors must always be NULL.
 548  */
 549 extern void     (*cl_inet_listen)(netstackid_t, uint8_t, sa_family_t,
 550                     uint8_t *, in_port_t, void *);
 551 extern void     (*cl_inet_unlisten)(netstackid_t, uint8_t, sa_family_t,
 552                     uint8_t *, in_port_t, void *);
 553 
 554 /*
 555  * Contracted Consolidation Private ioctl for aborting TCP connections.
 556  * In order to keep the offsets and size of the structure the same between
 557  * a 32-bit application and a 64-bit amd64 kernel, we use a #pragma
 558  * pack(4).
 559  */
 560 #define TCP_IOC_ABORT_CONN      (('T' << 8) + 91)
 561 
 562 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 563 #pragma pack(4)
 564 #endif
 565 
 566 typedef struct tcp_ioc_abort_conn_s {
 567         struct sockaddr_storage ac_local;       /* local addr and port */
 568         struct sockaddr_storage ac_remote;      /* remote addr and port */
 569         int32_t ac_start;                       /* start state */
 570         int32_t ac_end;                         /* end state  */
 571         int32_t ac_zoneid;                      /* zoneid */
 572 } tcp_ioc_abort_conn_t;
 573 
 574 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 575 #pragma pack()
 576 #endif
 577 
 578 #ifdef  __cplusplus
 579 }
 580 #endif
 581 
 582 #endif  /* _INET_TCP_H */