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  * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
  25  * Copyright (c) 2014, 2017 by Delphix. All rights reserved.
  26  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
  27  */
  28 /* Copyright (c) 1990 Mentat Inc. */
  29 
  30 #ifndef _INET_TCP_H
  31 #define _INET_TCP_H
  32 
  33 #ifdef  __cplusplus
  34 extern "C" {
  35 #endif
  36 
  37 #include <sys/inttypes.h>
  38 #include <netinet/ip6.h>
  39 #include <netinet/tcp.h>
  40 #include <sys/socket.h>
  41 #include <sys/socket_proto.h>
  42 #include <sys/md5.h>
  43 #include <inet/common.h>
  44 #include <inet/ip.h>
  45 #include <inet/ip6.h>
  46 #include <inet/mi.h>
  47 #include <inet/mib2.h>
  48 #include <inet/tcp_stack.h>
  49 #include <inet/tcp_sack.h>
  50 #include <inet/cc.h>
  51 
  52 /* TCP states */
  53 #define TCPS_CLOSED             -6
  54 #define TCPS_IDLE               -5      /* idle (opened, but not bound) */
  55 #define TCPS_BOUND              -4      /* bound, ready to connect or accept */
  56 #define TCPS_LISTEN             -3      /* listening for connection */
  57 #define TCPS_SYN_SENT           -2      /* active, have sent syn */
  58 #define TCPS_SYN_RCVD           -1      /* have received syn (and sent ours) */
  59 /* states < TCPS_ESTABLISHED are those where connections not established */
  60 #define TCPS_ESTABLISHED        0       /* established */
  61 #define TCPS_CLOSE_WAIT         1       /* rcvd fin, waiting for close */
  62 /* states > TCPS_CLOSE_WAIT are those where user has closed */
  63 #define TCPS_FIN_WAIT_1         2       /* have closed and sent fin */
  64 #define TCPS_CLOSING            3       /* closed, xchd FIN, await FIN ACK */
  65 #define TCPS_LAST_ACK           4       /* had fin and close; await FIN ACK */
  66 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
  67 #define TCPS_FIN_WAIT_2         5       /* have closed, fin is acked */
  68 #define TCPS_TIME_WAIT          6       /* in 2*msl quiet wait after close */
  69 
  70 /*
  71  * Internal flags used in conjunction with the packet header flags.
  72  * Used in tcp_input_data to keep track of what needs to be done.
  73  */
  74 #define TH_LIMIT_XMIT           0x0400  /* Limited xmit is needed */
  75 #define TH_XMIT_NEEDED          0x0800  /* Window opened - send queued data */
  76 #define TH_REXMIT_NEEDED        0x1000  /* Time expired for unacked data */
  77 #define TH_ACK_NEEDED           0x2000  /* Send an ack now. */
  78 #define TH_NEED_SACK_REXMIT     0x4000  /* Use SACK info to retransmission */
  79 #define TH_ACK_TIMER_NEEDED     0x8000  /* Start the delayed ACK timer */
  80 #define TH_ORDREL_NEEDED        0x10000 /* Generate an ordrel indication */
  81 #define TH_MARKNEXT_NEEDED      0x20000 /* Data should have MSGMARKNEXT */
  82 #define TH_SEND_URP_MARK        0x40000 /* Send up tcp_urp_mark_mp */
  83 
  84 /*
  85  * TCP sequence numbers are 32 bit integers operated
  86  * on with modular arithmetic.  These macros can be
  87  * used to compare such integers.
  88  */
  89 #define SEQ_LT(a, b)    ((int32_t)((a)-(b)) < 0)
  90 #define SEQ_LEQ(a, b)   ((int32_t)((a)-(b)) <= 0)
  91 #define SEQ_GT(a, b)    ((int32_t)((a)-(b)) > 0)
  92 #define SEQ_GEQ(a, b)   ((int32_t)((a)-(b)) >= 0)
  93 
  94 /* TCP Protocol header */
  95 typedef struct tcphdr_s {
  96         uint8_t         th_lport[2];    /* Source port */
  97         uint8_t         th_fport[2];    /* Destination port */
  98         uint8_t         th_seq[4];      /* Sequence number */
  99         uint8_t         th_ack[4];      /* Acknowledgement number */
 100         uint8_t         th_offset_and_rsrvd[1]; /* Offset to the packet data */
 101         uint8_t         th_flags[1];
 102         uint8_t         th_win[2];      /* Allocation number */
 103         uint8_t         th_sum[2];      /* TCP checksum */
 104         uint8_t         th_urp[2];      /* Urgent pointer */
 105 } tcph_t;
 106 
 107 #define TCP_HDR_LENGTH(tcph) \
 108         ((((tcph_t *)tcph)->th_offset_and_rsrvd[0] >>2) &(0xF << 2))
 109 #define TCP_MAX_COMBINED_HEADER_LENGTH  (60 + 60) /* Maxed out ip + tcp */
 110 #define TCP_MAX_IP_OPTIONS_LENGTH       (60 - IP_SIMPLE_HDR_LENGTH)
 111 #define TCP_MAX_HDR_LENGTH              60
 112 #define TCP_MAX_TCP_OPTIONS_LENGTH      (60 - sizeof (tcpha_t))
 113 #define TCP_MIN_HEADER_LENGTH           20
 114 #define TCP_MAXWIN                      65535
 115 #define TCP_PORT_LEN                    sizeof (in_port_t)
 116 #define TCP_MAX_WINSHIFT                14
 117 #define TCP_MAX_LARGEWIN                (TCP_MAXWIN << TCP_MAX_WINSHIFT)
 118 #define TCP_MAX_LSO_LENGTH      (IP_MAXPACKET - TCP_MAX_COMBINED_HEADER_LENGTH)
 119 
 120 #define TCPIP_HDR_LENGTH(mp, n)                                 \
 121         (n) = IPH_HDR_LENGTH((mp)->b_rptr),                  \
 122         (n) += TCP_HDR_LENGTH((tcpha_t *)&(mp)->b_rptr[(n)])
 123 
 124 /* TCP Protocol header (used if the header is known to be 32-bit aligned) */
 125 typedef struct tcphdra_s {
 126         in_port_t       tha_lport;      /* Source port */
 127         in_port_t       tha_fport;      /* Destination port */
 128         uint32_t        tha_seq;        /* Sequence number */
 129         uint32_t        tha_ack;        /* Acknowledgement number */
 130         uint8_t tha_offset_and_reserved; /* Offset to the packet data */
 131         uint8_t         tha_flags;
 132         uint16_t        tha_win;        /* Allocation number */
 133         uint16_t        tha_sum;        /* TCP checksum */
 134         uint16_t        tha_urp;        /* Urgent pointer */
 135 } tcpha_t;
 136 
 137 struct conn_s;
 138 struct tcp_listen_cnt_s;
 139 
 140 /*
 141  * Control structure for each open TCP stream,
 142  * defined only within the kernel or for a kmem user.
 143  * NOTE: tcp_reinit_values MUST have a line for each field in this structure!
 144  */
 145 #if (defined(_KERNEL) || defined(_KMEMUSER))
 146 
 147 typedef struct tcp_s {
 148         struct tcp_s    *tcp_time_wait_next;
 149                                 /* Pointer to next T/W block */
 150         struct tcp_s    *tcp_time_wait_prev;
 151                                 /* Pointer to previous T/W next */
 152         int64_t         tcp_time_wait_expire;
 153 
 154         struct conn_s   *tcp_connp;     /* back pointer to conn_t */
 155         tcp_stack_t     *tcp_tcps;      /* back pointer to tcp_stack_t */
 156 
 157         struct cc_algo  *tcp_cc_algo;   /* congestion control algorithm */
 158         struct cc_var   tcp_ccv;        /* congestion control specific vars */
 159 
 160         int32_t tcp_state;
 161         int32_t tcp_rcv_ws;             /* My window scale power */
 162         int32_t tcp_snd_ws;             /* Sender's window scale power */
 163         uint32_t tcp_ts_recent;         /* Timestamp of earliest unacked */
 164                                         /*  data segment */
 165         clock_t tcp_rto;                /* Round trip timeout */
 166         int64_t tcp_last_rcv_lbolt;
 167                                 /* lbolt on last packet, used for PAWS */
 168         uint32_t tcp_rto_initial;       /* Initial RTO */
 169         uint32_t tcp_rto_min;           /* Minimum RTO */
 170         uint32_t tcp_rto_max;           /* Maximum RTO */
 171 
 172         uint32_t tcp_snxt;              /* Senders next seq num */
 173         uint32_t tcp_swnd;              /* Senders window (relative to suna) */
 174         uint32_t tcp_mss;               /* Max segment size */
 175         uint32_t tcp_iss;               /* Initial send seq num */
 176         uint32_t tcp_rnxt;              /* Seq we expect to recv next */
 177         uint32_t tcp_rwnd;
 178 
 179         /* Fields arranged in approximate access order along main paths */
 180         mblk_t  *tcp_xmit_head;         /* Head of xmit/rexmit list */
 181         mblk_t  *tcp_xmit_last;         /* Last valid data seen by tcp_wput */
 182         mblk_t  *tcp_xmit_tail;         /* Last data sent */
 183         uint32_t tcp_unsent;            /* # of bytes in hand that are unsent */
 184         uint32_t tcp_xmit_tail_unsent;  /* # of unsent bytes in xmit_tail */
 185         uint32_t tcp_suna;              /* Sender unacknowledged */
 186         uint32_t tcp_rexmit_nxt;        /* Next rexmit seq num */
 187         uint32_t tcp_rexmit_max;        /* Max retran seq num */
 188         uint32_t tcp_cwnd;              /* Congestion window */
 189         int32_t tcp_cwnd_cnt;           /* cwnd cnt in congestion avoidance */
 190         uint32_t tcp_naglim;            /* Tunable nagle limit */
 191         uint32_t        tcp_valid_bits;
 192 #define TCP_ISS_VALID   0x1     /* Is the tcp_iss seq num active? */
 193 #define TCP_FSS_VALID   0x2     /* Is the tcp_fss seq num active? */
 194 #define TCP_URG_VALID   0x4     /* Is the tcp_urg seq num active? */
 195 #define TCP_OFO_FIN_VALID 0x8   /* Has TCP received an out of order FIN? */
 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         hrtime_t tcp_rtt_sum;           /* Round trip sum */
 284         uint32_t tcp_rtt_cnt;           /* Round trip count (non_dup ACKs) */
 285         hrtime_t tcp_rtt_sa;            /* Round trip smoothed average */
 286         hrtime_t tcp_rtt_sd;            /* Round trip smoothed deviation */
 287         uint32_t tcp_rtt_update;        /* Round trip update(s) */
 288         clock_t tcp_ms_we_have_waited;  /* Total retrans time */
 289 
 290         uint32_t tcp_swl1;              /* These help us avoid using stale */
 291         uint32_t tcp_swl2;              /*  packets to update state */
 292 
 293         uint32_t tcp_rack;              /* Seq # we have acked */
 294         uint32_t tcp_rack_cnt;          /* # of segs we have deferred ack */
 295         uint32_t tcp_rack_cur_max;      /* # of segs we may defer ack for now */
 296         uint32_t tcp_rack_abs_max;      /* # of segs we may defer ack ever */
 297         timeout_id_t    tcp_ack_tid;    /* Delayed ACK timer ID */
 298         timeout_id_t    tcp_push_tid;   /* Push timer ID */
 299 
 300         uint32_t tcp_max_swnd;          /* Maximum swnd we have seen */
 301 
 302         struct tcp_s *tcp_listener;     /* Our listener */
 303 
 304         uint32_t tcp_irs;               /* Initial recv seq num */
 305         uint32_t tcp_fss;               /* Final/fin send seq num */
 306         uint32_t tcp_urg;               /* Urgent data seq num */
 307 
 308         clock_t tcp_first_timer_threshold;  /* When to prod IP */
 309         clock_t tcp_second_timer_threshold; /* When to give up completely */
 310         clock_t tcp_first_ctimer_threshold; /* 1st threshold while connecting */
 311         clock_t tcp_second_ctimer_threshold; /* 2nd ... while connecting */
 312 
 313         uint32_t tcp_urp_last;          /* Last urp for which signal sent */
 314         mblk_t  *tcp_urp_mp;            /* T_EXDATA_IND for urgent byte */
 315         mblk_t  *tcp_urp_mark_mp;       /* zero-length marked/unmarked msg */
 316 
 317         int tcp_conn_req_cnt_q0;        /* # of conn reqs in SYN_RCVD */
 318         int tcp_conn_req_cnt_q; /* # of conn reqs in ESTABLISHED */
 319         int tcp_conn_req_max;   /* # of ESTABLISHED conn reqs allowed */
 320         t_scalar_t tcp_conn_req_seqnum; /* Incrementing pending conn req ID */
 321 #define tcp_ip_addr_cache       tcp_reass_tail
 322                                         /* Cache ip addresses that */
 323                                         /* complete the 3-way handshake */
 324         kmutex_t  tcp_eager_lock;
 325         struct tcp_s *tcp_eager_next_q; /* next eager in ESTABLISHED state */
 326         struct tcp_s *tcp_eager_last_q; /* last eager in ESTABLISHED state */
 327         struct tcp_s *tcp_eager_next_q0; /* next eager in SYN_RCVD state */
 328         struct tcp_s *tcp_eager_prev_q0; /* prev eager in SYN_RCVD state */
 329                                         /* all eagers form a circular list */
 330         boolean_t tcp_conn_def_q0;      /* move from q0 to q deferred */
 331 
 332         union {
 333             mblk_t *tcp_eager_conn_ind; /* T_CONN_IND waiting for 3rd ack. */
 334             mblk_t *tcp_opts_conn_req; /* T_CONN_REQ w/ options processed */
 335         } tcp_conn;
 336         uint32_t tcp_syn_rcvd_timeout;  /* How many SYN_RCVD timeout in q0 */
 337 
 338         /*
 339          * TCP Keepalive Timer members.
 340          * All keepalive timer intervals are in milliseconds.
 341          */
 342         int32_t tcp_ka_last_intrvl;     /* Last probe interval */
 343         timeout_id_t tcp_ka_tid;        /* Keepalive timer ID */
 344         uint32_t tcp_ka_interval;       /* Keepalive interval */
 345 
 346         /*
 347          * TCP connection is terminated if we don't hear back from the peer
 348          * for tcp_ka_abort_thres milliseconds after the first keepalive probe.
 349          * tcp_ka_rinterval is the interval in milliseconds between successive
 350          * keepalive probes. tcp_ka_cnt is the number of keepalive probes to
 351          * be sent before terminating the connection, if we don't hear back from
 352          * peer.
 353          * tcp_ka_abort_thres = tcp_ka_rinterval * tcp_ka_cnt
 354          */
 355         uint32_t tcp_ka_rinterval;      /* keepalive retransmit interval */
 356         uint32_t tcp_ka_abort_thres;    /* Keepalive abort threshold */
 357         uint32_t tcp_ka_cnt;            /* count of keepalive probes */
 358 
 359         int32_t tcp_client_errno;       /* How the client screwed up */
 360 
 361         /*
 362          * The header template lives in conn_ht_iphc allocated by tcp_build_hdrs
 363          * We maintain three pointers into conn_ht_iphc.
 364          */
 365         ipha_t  *tcp_ipha;              /* IPv4 header in conn_ht_iphc */
 366         ip6_t   *tcp_ip6h;              /* IPv6 header in conn_ht_iphc */
 367         tcpha_t *tcp_tcpha;             /* TCP header in conn_ht_iphc */
 368 
 369         uint16_t tcp_last_sent_len;     /* Record length for nagle */
 370         uint16_t tcp_last_recv_len;     /* Used by DTrace */
 371         uint16_t tcp_dupack_cnt;        /* # of consequtive duplicate acks */
 372 
 373         kmutex_t        *tcp_acceptor_lockp;    /* Ptr to tf_lock */
 374 
 375         mblk_t          *tcp_ordrel_mp;         /* T_ordrel_ind mblk */
 376         t_uscalar_t     tcp_acceptor_id;        /* ACCEPTOR_id */
 377 
 378         int             tcp_ipsec_overhead;
 379 
 380         uint_t          tcp_recvtos;    /* Last received IP_RECVTOS */
 381         uint_t          tcp_recvifindex; /* Last received IPV6_RCVPKTINFO */
 382         uint_t          tcp_recvhops;   /* Last received IPV6_RECVHOPLIMIT */
 383         uint_t          tcp_recvtclass; /* Last received IPV6_RECVTCLASS */
 384         ip6_hbh_t       *tcp_hopopts;   /* Last received IPV6_RECVHOPOPTS */
 385         ip6_dest_t      *tcp_dstopts;   /* Last received IPV6_RECVDSTOPTS */
 386         ip6_dest_t      *tcp_rthdrdstopts; /* Last recv IPV6_RECVRTHDRDSTOPTS */
 387         ip6_rthdr_t     *tcp_rthdr;     /* Last received IPV6_RECVRTHDR */
 388         uint_t          tcp_hopoptslen;
 389         uint_t          tcp_dstoptslen;
 390         uint_t          tcp_rthdrdstoptslen;
 391         uint_t          tcp_rthdrlen;
 392 
 393         mblk_t          *tcp_timercache;
 394 
 395         kmutex_t        tcp_closelock;
 396         kcondvar_t      tcp_closecv;
 397         uint8_t         tcp_closed;
 398         uint8_t         tcp_closeflags;
 399         mblk_t          tcp_closemp;
 400         timeout_id_t    tcp_linger_tid; /* Linger timer ID */
 401 
 402         struct tcp_s *tcp_acceptor_hash; /* Acceptor hash chain */
 403         struct tcp_s **tcp_ptpahn; /* Pointer to previous accept hash next. */
 404         struct tcp_s *tcp_bind_hash; /* Bind hash chain */
 405         struct tcp_s *tcp_bind_hash_port; /* tcp_t's bound to the same lport */
 406         struct tcp_s **tcp_ptpbhn;
 407 
 408         uint_t          tcp_maxpsz_multiplier;
 409 
 410         uint32_t        tcp_lso_max; /* maximum LSO payload */
 411 
 412         uint32_t        tcp_ofo_fin_seq; /* Recv out of order FIN seq num */
 413         uint32_t        tcp_cwr_snd_max;
 414 
 415         struct tcp_s *tcp_saved_listener;       /* saved value of listener */
 416 
 417         uint32_t        tcp_in_ack_unsent;      /* ACK for unsent data cnt. */
 418 
 419         /*
 420          * All fusion-related fields are protected by squeue.
 421          */
 422         struct tcp_s *tcp_loopback_peer;        /* peer tcp for loopback */
 423         mblk_t  *tcp_fused_sigurg_mp;           /* M_PCSIG mblk for SIGURG */
 424 
 425         uint32_t
 426                 tcp_fused : 1,          /* loopback tcp in fusion mode */
 427                 tcp_unfusable : 1,      /* fusion not allowed on endpoint */
 428                 tcp_fused_sigurg : 1,   /* send SIGURG upon draining */
 429 
 430                 tcp_fuse_to_bit_31 : 29;
 431 
 432         kmutex_t tcp_non_sq_lock;
 433 
 434         /*
 435          * This variable is accessed without any lock protection
 436          * and therefore must not be declared as a bit field along
 437          * with the rest which require such condition.
 438          */
 439         boolean_t       tcp_issocket;   /* this is a socket tcp */
 440 
 441         /* protected by the tcp_non_sq_lock lock */
 442         uint32_t        tcp_squeue_bytes;
 443 
 444         /*
 445          * tcp_closemp_used is protected by listener's tcp_eager_lock
 446          * when used for eagers. When used for a tcp in TIME_WAIT state
 447          * or in tcp_close(), it is not protected by any lock as we
 448          * do not expect any other thread to use it concurrently.
 449          * We do allow re-use of tcp_closemp in tcp_time_wait_collector()
 450          * and tcp_close() but not concurrently.
 451          */
 452         boolean_t tcp_closemp_used;
 453 
 454         /*
 455          * previous and next eagers in the list of droppable eagers. See
 456          * the comments before MAKE_DROPPABLE(). These pointers are
 457          * protected by listener's tcp_eager_lock.
 458          */
 459         struct tcp_s    *tcp_eager_prev_drop_q0;
 460         struct tcp_s    *tcp_eager_next_drop_q0;
 461 
 462         /*
 463          * Have we flow controlled xmitter?
 464          * This variable can be modified outside the squeue and hence must
 465          * not be declared as a bit field along with the rest that are
 466          * modified only within the squeue.
 467          * protected by the tcp_non_sq_lock lock.
 468          */
 469         boolean_t       tcp_flow_stopped;
 470 
 471         /*
 472          * Sender's next sequence number at the time the window was shrunk.
 473          */
 474         uint32_t        tcp_snxt_shrunk;
 475 
 476         /*
 477          * Socket generation number which is bumped when a connection attempt
 478          * is initiated. Its main purpose is to ensure that the socket does not
 479          * miss the asynchronous connected/disconnected notification.
 480          */
 481         sock_connid_t   tcp_connid;
 482 
 483         /* mblk_t used to enter TCP's squeue from the service routine. */
 484         mblk_t          *tcp_rsrv_mp;
 485         /* Mutex for accessing tcp_rsrv_mp */
 486         kmutex_t        tcp_rsrv_mp_lock;
 487 
 488         /* For connection counting. */
 489         struct tcp_listen_cnt_s *tcp_listen_cnt;
 490 
 491         /* Segment reassembly timer. */
 492         timeout_id_t            tcp_reass_tid;
 493 
 494         /* FIN-WAIT-2 flush timeout */
 495         uint32_t                tcp_fin_wait_2_flush_interval;
 496 
 497         tcp_conn_stats_t        tcp_cs;
 498 
 499 #ifdef DEBUG
 500         pc_t                    tcmp_stk[15];
 501 #endif
 502 } tcp_t;
 503 
 504 #ifdef DEBUG
 505 #define TCP_DEBUG_GETPCSTACK(buffer, depth)     ((void) getpcstack(buffer, \
 506                                                     depth))
 507 #else
 508 #define TCP_DEBUG_GETPCSTACK(buffer, depth)
 509 #endif
 510 
 511 extern void     tcp_conn_reclaim(void *);
 512 extern void     tcp_free(tcp_t *tcp);
 513 extern void     tcp_ddi_g_init(void);
 514 extern void     tcp_ddi_g_destroy(void);
 515 extern conn_t   *tcp_get_conn(void *arg, tcp_stack_t *);
 516 extern mblk_t   *tcp_snmp_get(queue_t *, mblk_t *, boolean_t);
 517 extern int      tcp_snmp_set(queue_t *, int, int, uchar_t *, int len);
 518 
 519 /* Pad for the tf_t structure to avoid false cache line sharing. */
 520 #define TF_CACHEL_PAD   64
 521 
 522 /*
 523  * The TCP Fanout structure for bind and acceptor hashes.
 524  * The hash tables and their linkage (tcp_*_hash, tcp_ptp*hn) are
 525  * protected by the per-bucket tf_lock.  Each tcp_t
 526  * inserted in the list points back at this lock using tcp_*_lockp.
 527  *
 528  * The bind and acceptor hash queues are lists of tcp_t.
 529  */
 530 /* listener hash and acceptor hash queue head */
 531 typedef struct tf_s {
 532         tcp_t           *tf_tcp;
 533         kmutex_t        tf_lock;
 534         unsigned char   tf_pad[TF_CACHEL_PAD -
 535             (sizeof (tcp_t *) + sizeof (kmutex_t))];
 536 } tf_t;
 537 
 538 
 539 /* Also used in ipclassifier.c */
 540 extern struct kmem_cache  *tcp_sack_info_cache;
 541 
 542 #endif  /* (defined(_KERNEL) || defined(_KMEMUSER)) */
 543 
 544 /* Contract private interface between TCP and Clustering. */
 545 
 546 #define CL_TCPI_V1      1       /* cl_tcpi_version number */
 547 
 548 typedef struct cl_tcp_info_s {
 549         ushort_t        cl_tcpi_version;        /* cl_tcp_info_t's version no */
 550         ushort_t        cl_tcpi_ipversion;      /* IP version */
 551         int32_t         cl_tcpi_state;          /* TCP state */
 552         in_port_t       cl_tcpi_lport;          /* Local port */
 553         in_port_t       cl_tcpi_fport;          /* Remote port */
 554         in6_addr_t      cl_tcpi_laddr_v6;       /* Local IP address */
 555         in6_addr_t      cl_tcpi_faddr_v6;       /* Remote IP address */
 556 #ifdef _KERNEL
 557 /* Note: V4_PART_OF_V6 is meant to be used only for _KERNEL defined stuff */
 558 #define cl_tcpi_laddr   V4_PART_OF_V6(cl_tcpi_laddr_v6)
 559 #define cl_tcpi_faddr   V4_PART_OF_V6(cl_tcpi_faddr_v6)
 560 
 561 #endif  /* _KERNEL */
 562 } cl_tcp_info_t;
 563 
 564 /*
 565  * Hook functions to enable cluster networking
 566  * On non-clustered systems these vectors must always be NULL.
 567  */
 568 extern void     (*cl_inet_listen)(netstackid_t, uint8_t, sa_family_t,
 569                     uint8_t *, in_port_t, void *);
 570 extern void     (*cl_inet_unlisten)(netstackid_t, uint8_t, sa_family_t,
 571                     uint8_t *, in_port_t, void *);
 572 
 573 /*
 574  * Contracted Consolidation Private ioctl for aborting TCP connections.
 575  * In order to keep the offsets and size of the structure the same between
 576  * a 32-bit application and a 64-bit amd64 kernel, we use a #pragma
 577  * pack(4).
 578  */
 579 #define TCP_IOC_ABORT_CONN      (('T' << 8) + 91)
 580 
 581 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 582 #pragma pack(4)
 583 #endif
 584 
 585 typedef struct tcp_ioc_abort_conn_s {
 586         struct sockaddr_storage ac_local;       /* local addr and port */
 587         struct sockaddr_storage ac_remote;      /* remote addr and port */
 588         int32_t ac_start;                       /* start state */
 589         int32_t ac_end;                         /* end state  */
 590         int32_t ac_zoneid;                      /* zoneid */
 591 } tcp_ioc_abort_conn_t;
 592 
 593 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
 594 #pragma pack()
 595 #endif
 596 
 597 #ifdef  __cplusplus
 598 }
 599 #endif
 600 
 601 #endif  /* _INET_TCP_H */