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) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright (c) 2011, Joyent Inc. All rights reserved.
  25  * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
  26  * Copyright (c) 2013,2014 by Delphix. All rights reserved.
  27  * Copyright 2014, OmniTI Computer Consulting, Inc. All rights reserved.
  28  */
  29 /* Copyright (c) 1990 Mentat Inc. */
  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/timod.h>
  40 #include <sys/ddi.h>
  41 #include <sys/sunddi.h>
  42 #include <sys/suntpi.h>
  43 #include <sys/xti_inet.h>
  44 #include <sys/cmn_err.h>
  45 #include <sys/debug.h>
  46 #include <sys/sdt.h>
  47 #include <sys/vtrace.h>
  48 #include <sys/kmem.h>
  49 #include <sys/ethernet.h>
  50 #include <sys/cpuvar.h>
  51 #include <sys/dlpi.h>
  52 #include <sys/pattr.h>
  53 #include <sys/policy.h>
  54 #include <sys/priv.h>
  55 #include <sys/zone.h>
  56 #include <sys/sunldi.h>
  57 
  58 #include <sys/errno.h>
  59 #include <sys/signal.h>
  60 #include <sys/socket.h>
  61 #include <sys/socketvar.h>
  62 #include <sys/sockio.h>
  63 #include <sys/isa_defs.h>
  64 #include <sys/md5.h>
  65 #include <sys/random.h>
  66 #include <sys/uio.h>
  67 #include <sys/systm.h>
  68 #include <netinet/in.h>
  69 #include <netinet/tcp.h>
  70 #include <netinet/ip6.h>
  71 #include <netinet/icmp6.h>
  72 #include <net/if.h>
  73 #include <net/route.h>
  74 #include <inet/ipsec_impl.h>
  75 
  76 #include <inet/common.h>
  77 #include <inet/ip.h>
  78 #include <inet/ip_impl.h>
  79 #include <inet/ip6.h>
  80 #include <inet/ip_ndp.h>
  81 #include <inet/proto_set.h>
  82 #include <inet/mib2.h>
  83 #include <inet/optcom.h>
  84 #include <inet/snmpcom.h>
  85 #include <inet/kstatcom.h>
  86 #include <inet/tcp.h>
  87 #include <inet/tcp_impl.h>
  88 #include <inet/tcp_cluster.h>
  89 #include <inet/udp_impl.h>
  90 #include <net/pfkeyv2.h>
  91 #include <inet/ipdrop.h>
  92 
  93 #include <inet/ipclassifier.h>
  94 #include <inet/ip_ire.h>
  95 #include <inet/ip_ftable.h>
  96 #include <inet/ip_if.h>
  97 #include <inet/ipp_common.h>
  98 #include <inet/ip_rts.h>
  99 #include <inet/ip_netinfo.h>
 100 #include <sys/squeue_impl.h>
 101 #include <sys/squeue.h>
 102 #include <sys/tsol/label.h>
 103 #include <sys/tsol/tnet.h>
 104 #include <rpc/pmap_prot.h>
 105 #include <sys/callo.h>
 106 
 107 /*
 108  * TCP Notes: aka FireEngine Phase I (PSARC 2002/433)
 109  *
 110  * (Read the detailed design doc in PSARC case directory)
 111  *
 112  * The entire tcp state is contained in tcp_t and conn_t structure
 113  * which are allocated in tandem using ipcl_conn_create() and passing
 114  * IPCL_TCPCONN as a flag. We use 'conn_ref' and 'conn_lock' to protect
 115  * the references on the tcp_t. The tcp_t structure is never compressed
 116  * and packets always land on the correct TCP perimeter from the time
 117  * eager is created till the time tcp_t dies (as such the old mentat
 118  * TCP global queue is not used for detached state and no IPSEC checking
 119  * is required). The global queue is still allocated to send out resets
 120  * for connection which have no listeners and IP directly calls
 121  * tcp_xmit_listeners_reset() which does any policy check.
 122  *
 123  * Protection and Synchronisation mechanism:
 124  *
 125  * The tcp data structure does not use any kind of lock for protecting
 126  * its state but instead uses 'squeues' for mutual exclusion from various
 127  * read and write side threads. To access a tcp member, the thread should
 128  * always be behind squeue (via squeue_enter with flags as SQ_FILL, SQ_PROCESS,
 129  * or SQ_NODRAIN). Since the squeues allow a direct function call, caller
 130  * can pass any tcp function having prototype of edesc_t as argument
 131  * (different from traditional STREAMs model where packets come in only
 132  * designated entry points). The list of functions that can be directly
 133  * called via squeue are listed before the usual function prototype.
 134  *
 135  * Referencing:
 136  *
 137  * TCP is MT-Hot and we use a reference based scheme to make sure that the
 138  * tcp structure doesn't disappear when its needed. When the application
 139  * creates an outgoing connection or accepts an incoming connection, we
 140  * start out with 2 references on 'conn_ref'. One for TCP and one for IP.
 141  * The IP reference is just a symbolic reference since ip_tcpclose()
 142  * looks at tcp structure after tcp_close_output() returns which could
 143  * have dropped the last TCP reference. So as long as the connection is
 144  * in attached state i.e. !TCP_IS_DETACHED, we have 2 references on the
 145  * conn_t. The classifier puts its own reference when the connection is
 146  * inserted in listen or connected hash. Anytime a thread needs to enter
 147  * the tcp connection perimeter, it retrieves the conn/tcp from q->ptr
 148  * on write side or by doing a classify on read side and then puts a
 149  * reference on the conn before doing squeue_enter/tryenter/fill. For
 150  * read side, the classifier itself puts the reference under fanout lock
 151  * to make sure that tcp can't disappear before it gets processed. The
 152  * squeue will drop this reference automatically so the called function
 153  * doesn't have to do a DEC_REF.
 154  *
 155  * Opening a new connection:
 156  *
 157  * The outgoing connection open is pretty simple. tcp_open() does the
 158  * work in creating the conn/tcp structure and initializing it. The
 159  * squeue assignment is done based on the CPU the application
 160  * is running on. So for outbound connections, processing is always done
 161  * on application CPU which might be different from the incoming CPU
 162  * being interrupted by the NIC. An optimal way would be to figure out
 163  * the NIC <-> CPU binding at listen time, and assign the outgoing
 164  * connection to the squeue attached to the CPU that will be interrupted
 165  * for incoming packets (we know the NIC based on the bind IP address).
 166  * This might seem like a problem if more data is going out but the
 167  * fact is that in most cases the transmit is ACK driven transmit where
 168  * the outgoing data normally sits on TCP's xmit queue waiting to be
 169  * transmitted.
 170  *
 171  * Accepting a connection:
 172  *
 173  * This is a more interesting case because of various races involved in
 174  * establishing a eager in its own perimeter. Read the meta comment on
 175  * top of tcp_input_listener(). But briefly, the squeue is picked by
 176  * ip_fanout based on the ring or the sender (if loopback).
 177  *
 178  * Closing a connection:
 179  *
 180  * The close is fairly straight forward. tcp_close() calls tcp_close_output()
 181  * via squeue to do the close and mark the tcp as detached if the connection
 182  * was in state TCPS_ESTABLISHED or greater. In the later case, TCP keep its
 183  * reference but tcp_close() drop IP's reference always. So if tcp was
 184  * not killed, it is sitting in time_wait list with 2 reference - 1 for TCP
 185  * and 1 because it is in classifier's connected hash. This is the condition
 186  * we use to determine that its OK to clean up the tcp outside of squeue
 187  * when time wait expires (check the ref under fanout and conn_lock and
 188  * if it is 2, remove it from fanout hash and kill it).
 189  *
 190  * Although close just drops the necessary references and marks the
 191  * tcp_detached state, tcp_close needs to know the tcp_detached has been
 192  * set (under squeue) before letting the STREAM go away (because a
 193  * inbound packet might attempt to go up the STREAM while the close
 194  * has happened and tcp_detached is not set). So a special lock and
 195  * flag is used along with a condition variable (tcp_closelock, tcp_closed,
 196  * and tcp_closecv) to signal tcp_close that tcp_close_out() has marked
 197  * tcp_detached.
 198  *
 199  * Special provisions and fast paths:
 200  *
 201  * We make special provisions for sockfs by marking tcp_issocket
 202  * whenever we have only sockfs on top of TCP. This allows us to skip
 203  * putting the tcp in acceptor hash since a sockfs listener can never
 204  * become acceptor and also avoid allocating a tcp_t for acceptor STREAM
 205  * since eager has already been allocated and the accept now happens
 206  * on acceptor STREAM. There is a big blob of comment on top of
 207  * tcp_input_listener explaining the new accept. When socket is POP'd,
 208  * sockfs sends us an ioctl to mark the fact and we go back to old
 209  * behaviour. Once tcp_issocket is unset, its never set for the
 210  * life of that connection.
 211  *
 212  * IPsec notes :
 213  *
 214  * Since a packet is always executed on the correct TCP perimeter
 215  * all IPsec processing is defered to IP including checking new
 216  * connections and setting IPSEC policies for new connection. The
 217  * only exception is tcp_xmit_listeners_reset() which is called
 218  * directly from IP and needs to policy check to see if TH_RST
 219  * can be sent out.
 220  */
 221 
 222 /*
 223  * Values for squeue switch:
 224  * 1: SQ_NODRAIN
 225  * 2: SQ_PROCESS
 226  * 3: SQ_FILL
 227  */
 228 int tcp_squeue_wput = 2;        /* /etc/systems */
 229 int tcp_squeue_flag;
 230 
 231 /*
 232  * To prevent memory hog, limit the number of entries in tcp_free_list
 233  * to 1% of available memory / number of cpus
 234  */
 235 uint_t tcp_free_list_max_cnt = 0;
 236 
 237 #define TIDUSZ  4096    /* transport interface data unit size */
 238 
 239 /*
 240  * Size of acceptor hash list.  It has to be a power of 2 for hashing.
 241  */
 242 #define TCP_ACCEPTOR_FANOUT_SIZE                512
 243 
 244 #ifdef  _ILP32
 245 #define TCP_ACCEPTOR_HASH(accid)                                        \
 246                 (((uint_t)(accid) >> 8) & (TCP_ACCEPTOR_FANOUT_SIZE - 1))
 247 #else
 248 #define TCP_ACCEPTOR_HASH(accid)                                        \
 249                 ((uint_t)(accid) & (TCP_ACCEPTOR_FANOUT_SIZE - 1))
 250 #endif  /* _ILP32 */
 251 
 252 /*
 253  * Minimum number of connections which can be created per listener.  Used
 254  * when the listener connection count is in effect.
 255  */
 256 static uint32_t tcp_min_conn_listener = 2;
 257 
 258 uint32_t tcp_early_abort = 30;
 259 
 260 /* TCP Timer control structure */
 261 typedef struct tcpt_s {
 262         pfv_t   tcpt_pfv;       /* The routine we are to call */
 263         tcp_t   *tcpt_tcp;      /* The parameter we are to pass in */
 264 } tcpt_t;
 265 
 266 /*
 267  * Functions called directly via squeue having a prototype of edesc_t.
 268  */
 269 void            tcp_input_listener(void *arg, mblk_t *mp, void *arg2,
 270     ip_recv_attr_t *ira);
 271 void            tcp_input_data(void *arg, mblk_t *mp, void *arg2,
 272     ip_recv_attr_t *ira);
 273 static void     tcp_linger_interrupted(void *arg, mblk_t *mp, void *arg2,
 274     ip_recv_attr_t *dummy);
 275 
 276 
 277 /* Prototype for TCP functions */
 278 static void     tcp_random_init(void);
 279 int             tcp_random(void);
 280 static int      tcp_connect_ipv4(tcp_t *tcp, ipaddr_t *dstaddrp,
 281                     in_port_t dstport, uint_t srcid);
 282 static int      tcp_connect_ipv6(tcp_t *tcp, in6_addr_t *dstaddrp,
 283                     in_port_t dstport, uint32_t flowinfo,
 284                     uint_t srcid, uint32_t scope_id);
 285 static void     tcp_iss_init(tcp_t *tcp);
 286 static void     tcp_reinit(tcp_t *tcp);
 287 static void     tcp_reinit_values(tcp_t *tcp);
 288 
 289 static int      tcp_wsrv(queue_t *q);
 290 static void     tcp_update_lso(tcp_t *tcp, ip_xmit_attr_t *ixa);
 291 static void     tcp_update_zcopy(tcp_t *tcp);
 292 static void     tcp_notify(void *, ip_xmit_attr_t *, ixa_notify_type_t,
 293     ixa_notify_arg_t);
 294 static void     *tcp_stack_init(netstackid_t stackid, netstack_t *ns);
 295 static void     tcp_stack_fini(netstackid_t stackid, void *arg);
 296 
 297 static int      tcp_squeue_switch(int);
 298 
 299 static int      tcp_open(queue_t *, dev_t *, int, int, cred_t *, boolean_t);
 300 static int      tcp_openv4(queue_t *, dev_t *, int, int, cred_t *);
 301 static int      tcp_openv6(queue_t *, dev_t *, int, int, cred_t *);
 302 
 303 static void     tcp_squeue_add(squeue_t *);
 304 
 305 struct module_info tcp_rinfo =  {
 306         TCP_MOD_ID, TCP_MOD_NAME, 0, INFPSZ, TCP_RECV_HIWATER, TCP_RECV_LOWATER
 307 };
 308 
 309 static struct module_info tcp_winfo =  {
 310         TCP_MOD_ID, TCP_MOD_NAME, 0, INFPSZ, 127, 16
 311 };
 312 
 313 /*
 314  * Entry points for TCP as a device. The normal case which supports
 315  * the TCP functionality.
 316  * We have separate open functions for the /dev/tcp and /dev/tcp6 devices.
 317  */
 318 struct qinit tcp_rinitv4 = {
 319         NULL, tcp_rsrv, tcp_openv4, tcp_tpi_close, NULL, &tcp_rinfo
 320 };
 321 
 322 struct qinit tcp_rinitv6 = {
 323         NULL, tcp_rsrv, tcp_openv6, tcp_tpi_close, NULL, &tcp_rinfo
 324 };
 325 
 326 struct qinit tcp_winit = {
 327         tcp_wput, tcp_wsrv, NULL, NULL, NULL, &tcp_winfo
 328 };
 329 
 330 /* Initial entry point for TCP in socket mode. */
 331 struct qinit tcp_sock_winit = {
 332         tcp_wput_sock, tcp_wsrv, NULL, NULL, NULL, &tcp_winfo
 333 };
 334 
 335 /* TCP entry point during fallback */
 336 struct qinit tcp_fallback_sock_winit = {
 337         tcp_wput_fallback, NULL, NULL, NULL, NULL, &tcp_winfo
 338 };
 339 
 340 /*
 341  * Entry points for TCP as a acceptor STREAM opened by sockfs when doing
 342  * an accept. Avoid allocating data structures since eager has already
 343  * been created.
 344  */
 345 struct qinit tcp_acceptor_rinit = {
 346         NULL, tcp_rsrv, NULL, tcp_tpi_close_accept, NULL, &tcp_winfo
 347 };
 348 
 349 struct qinit tcp_acceptor_winit = {
 350         tcp_tpi_accept, NULL, NULL, NULL, NULL, &tcp_winfo
 351 };
 352 
 353 /* For AF_INET aka /dev/tcp */
 354 struct streamtab tcpinfov4 = {
 355         &tcp_rinitv4, &tcp_winit
 356 };
 357 
 358 /* For AF_INET6 aka /dev/tcp6 */
 359 struct streamtab tcpinfov6 = {
 360         &tcp_rinitv6, &tcp_winit
 361 };
 362 
 363 /*
 364  * Following assumes TPI alignment requirements stay along 32 bit
 365  * boundaries
 366  */
 367 #define ROUNDUP32(x) \
 368         (((x) + (sizeof (int32_t) - 1)) & ~(sizeof (int32_t) - 1))
 369 
 370 /* Template for response to info request. */
 371 struct T_info_ack tcp_g_t_info_ack = {
 372         T_INFO_ACK,             /* PRIM_type */
 373         0,                      /* TSDU_size */
 374         T_INFINITE,             /* ETSDU_size */
 375         T_INVALID,              /* CDATA_size */
 376         T_INVALID,              /* DDATA_size */
 377         sizeof (sin_t),         /* ADDR_size */
 378         0,                      /* OPT_size - not initialized here */
 379         TIDUSZ,                 /* TIDU_size */
 380         T_COTS_ORD,             /* SERV_type */
 381         TCPS_IDLE,              /* CURRENT_state */
 382         (XPG4_1|EXPINLINE)      /* PROVIDER_flag */
 383 };
 384 
 385 struct T_info_ack tcp_g_t_info_ack_v6 = {
 386         T_INFO_ACK,             /* PRIM_type */
 387         0,                      /* TSDU_size */
 388         T_INFINITE,             /* ETSDU_size */
 389         T_INVALID,              /* CDATA_size */
 390         T_INVALID,              /* DDATA_size */
 391         sizeof (sin6_t),        /* ADDR_size */
 392         0,                      /* OPT_size - not initialized here */
 393         TIDUSZ,         /* TIDU_size */
 394         T_COTS_ORD,             /* SERV_type */
 395         TCPS_IDLE,              /* CURRENT_state */
 396         (XPG4_1|EXPINLINE)      /* PROVIDER_flag */
 397 };
 398 
 399 /*
 400  * TCP tunables related declarations. Definitions are in tcp_tunables.c
 401  */
 402 extern mod_prop_info_t tcp_propinfo_tbl[];
 403 extern int tcp_propinfo_count;
 404 
 405 #define IS_VMLOANED_MBLK(mp) \
 406         (((mp)->b_datap->db_struioflag & STRUIO_ZC) != 0)
 407 
 408 uint32_t do_tcpzcopy = 1;               /* 0: disable, 1: enable, 2: force */
 409 
 410 /*
 411  * Forces all connections to obey the value of the tcps_maxpsz_multiplier
 412  * tunable settable via NDD.  Otherwise, the per-connection behavior is
 413  * determined dynamically during tcp_set_destination(), which is the default.
 414  */
 415 boolean_t tcp_static_maxpsz = B_FALSE;
 416 
 417 /*
 418  * If the receive buffer size is changed, this function is called to update
 419  * the upper socket layer on the new delayed receive wake up threshold.
 420  */
 421 static void
 422 tcp_set_recv_threshold(tcp_t *tcp, uint32_t new_rcvthresh)
 423 {
 424         uint32_t default_threshold = SOCKET_RECVHIWATER >> 3;
 425 
 426         if (IPCL_IS_NONSTR(tcp->tcp_connp)) {
 427                 conn_t *connp = tcp->tcp_connp;
 428                 struct sock_proto_props sopp;
 429 
 430                 /*
 431                  * only increase rcvthresh upto default_threshold
 432                  */
 433                 if (new_rcvthresh > default_threshold)
 434                         new_rcvthresh = default_threshold;
 435 
 436                 sopp.sopp_flags = SOCKOPT_RCVTHRESH;
 437                 sopp.sopp_rcvthresh = new_rcvthresh;
 438 
 439                 (*connp->conn_upcalls->su_set_proto_props)
 440                     (connp->conn_upper_handle, &sopp);
 441         }
 442 }
 443 
 444 /*
 445  * Figure out the value of window scale opton.  Note that the rwnd is
 446  * ASSUMED to be rounded up to the nearest MSS before the calculation.
 447  * We cannot find the scale value and then do a round up of tcp_rwnd
 448  * because the scale value may not be correct after that.
 449  *
 450  * Set the compiler flag to make this function inline.
 451  */
 452 void
 453 tcp_set_ws_value(tcp_t *tcp)
 454 {
 455         int i;
 456         uint32_t rwnd = tcp->tcp_rwnd;
 457 
 458         for (i = 0; rwnd > TCP_MAXWIN && i < TCP_MAX_WINSHIFT;
 459             i++, rwnd >>= 1)
 460                 ;
 461         tcp->tcp_rcv_ws = i;
 462 }
 463 
 464 /*
 465  * Remove cached/latched IPsec references.
 466  */
 467 void
 468 tcp_ipsec_cleanup(tcp_t *tcp)
 469 {
 470         conn_t          *connp = tcp->tcp_connp;
 471 
 472         ASSERT(connp->conn_flags & IPCL_TCPCONN);
 473 
 474         if (connp->conn_latch != NULL) {
 475                 IPLATCH_REFRELE(connp->conn_latch);
 476                 connp->conn_latch = NULL;
 477         }
 478         if (connp->conn_latch_in_policy != NULL) {
 479                 IPPOL_REFRELE(connp->conn_latch_in_policy);
 480                 connp->conn_latch_in_policy = NULL;
 481         }
 482         if (connp->conn_latch_in_action != NULL) {
 483                 IPACT_REFRELE(connp->conn_latch_in_action);
 484                 connp->conn_latch_in_action = NULL;
 485         }
 486         if (connp->conn_policy != NULL) {
 487                 IPPH_REFRELE(connp->conn_policy, connp->conn_netstack);
 488                 connp->conn_policy = NULL;
 489         }
 490 }
 491 
 492 /*
 493  * Cleaup before placing on free list.
 494  * Disassociate from the netstack/tcp_stack_t since the freelist
 495  * is per squeue and not per netstack.
 496  */
 497 void
 498 tcp_cleanup(tcp_t *tcp)
 499 {
 500         mblk_t          *mp;
 501         conn_t          *connp = tcp->tcp_connp;
 502         tcp_stack_t     *tcps = tcp->tcp_tcps;
 503         netstack_t      *ns = tcps->tcps_netstack;
 504         mblk_t          *tcp_rsrv_mp;
 505 
 506         tcp_bind_hash_remove(tcp);
 507 
 508         /* Cleanup that which needs the netstack first */
 509         tcp_ipsec_cleanup(tcp);
 510         ixa_cleanup(connp->conn_ixa);
 511 
 512         if (connp->conn_ht_iphc != NULL) {
 513                 kmem_free(connp->conn_ht_iphc, connp->conn_ht_iphc_allocated);
 514                 connp->conn_ht_iphc = NULL;
 515                 connp->conn_ht_iphc_allocated = 0;
 516                 connp->conn_ht_iphc_len = 0;
 517                 connp->conn_ht_ulp = NULL;
 518                 connp->conn_ht_ulp_len = 0;
 519                 tcp->tcp_ipha = NULL;
 520                 tcp->tcp_ip6h = NULL;
 521                 tcp->tcp_tcpha = NULL;
 522         }
 523 
 524         /* We clear any IP_OPTIONS and extension headers */
 525         ip_pkt_free(&connp->conn_xmit_ipp);
 526 
 527         tcp_free(tcp);
 528 
 529         /*
 530          * Since we will bzero the entire structure, we need to
 531          * remove it and reinsert it in global hash list. We
 532          * know the walkers can't get to this conn because we
 533          * had set CONDEMNED flag earlier and checked reference
 534          * under conn_lock so walker won't pick it and when we
 535          * go the ipcl_globalhash_remove() below, no walker
 536          * can get to it.
 537          */
 538         ipcl_globalhash_remove(connp);
 539 
 540         /* Save some state */
 541         mp = tcp->tcp_timercache;
 542 
 543         tcp_rsrv_mp = tcp->tcp_rsrv_mp;
 544 
 545         if (connp->conn_cred != NULL) {
 546                 crfree(connp->conn_cred);
 547                 connp->conn_cred = NULL;
 548         }
 549         ipcl_conn_cleanup(connp);
 550         connp->conn_flags = IPCL_TCPCONN;
 551 
 552         /*
 553          * Now it is safe to decrement the reference counts.
 554          * This might be the last reference on the netstack
 555          * in which case it will cause the freeing of the IP Instance.
 556          */
 557         connp->conn_netstack = NULL;
 558         connp->conn_ixa->ixa_ipst = NULL;
 559         netstack_rele(ns);
 560         ASSERT(tcps != NULL);
 561         tcp->tcp_tcps = NULL;
 562 
 563         bzero(tcp, sizeof (tcp_t));
 564 
 565         /* restore the state */
 566         tcp->tcp_timercache = mp;
 567 
 568         tcp->tcp_rsrv_mp = tcp_rsrv_mp;
 569 
 570         tcp->tcp_connp = connp;
 571 
 572         ASSERT(connp->conn_tcp == tcp);
 573         ASSERT(connp->conn_flags & IPCL_TCPCONN);
 574         connp->conn_state_flags = CONN_INCIPIENT;
 575         ASSERT(connp->conn_proto == IPPROTO_TCP);
 576         ASSERT(connp->conn_ref == 1);
 577 }
 578 
 579 /*
 580  * Adapt to the information, such as rtt and rtt_sd, provided from the
 581  * DCE and IRE maintained by IP.
 582  *
 583  * Checks for multicast and broadcast destination address.
 584  * Returns zero if ok; an errno on failure.
 585  *
 586  * Note that the MSS calculation here is based on the info given in
 587  * the DCE and IRE.  We do not do any calculation based on TCP options.  They
 588  * will be handled in tcp_input_data() when TCP knows which options to use.
 589  *
 590  * Note on how TCP gets its parameters for a connection.
 591  *
 592  * When a tcp_t structure is allocated, it gets all the default parameters.
 593  * In tcp_set_destination(), it gets those metric parameters, like rtt, rtt_sd,
 594  * spipe, rpipe, ... from the route metrics.  Route metric overrides the
 595  * default.
 596  *
 597  * An incoming SYN with a multicast or broadcast destination address is dropped
 598  * in ip_fanout_v4/v6.
 599  *
 600  * An incoming SYN with a multicast or broadcast source address is always
 601  * dropped in tcp_set_destination, since IPDF_ALLOW_MCBC is not set in
 602  * conn_connect.
 603  * The same logic in tcp_set_destination also serves to
 604  * reject an attempt to connect to a broadcast or multicast (destination)
 605  * address.
 606  */
 607 int
 608 tcp_set_destination(tcp_t *tcp)
 609 {
 610         uint32_t        mss_max;
 611         uint32_t        mss;
 612         boolean_t       tcp_detached = TCP_IS_DETACHED(tcp);
 613         conn_t          *connp = tcp->tcp_connp;
 614         tcp_stack_t     *tcps = tcp->tcp_tcps;
 615         iulp_t          uinfo;
 616         int             error;
 617         uint32_t        flags;
 618 
 619         flags = IPDF_LSO | IPDF_ZCOPY;
 620         /*
 621          * Make sure we have a dce for the destination to avoid dce_ident
 622          * contention for connected sockets.
 623          */
 624         flags |= IPDF_UNIQUE_DCE;
 625 
 626         if (!tcps->tcps_ignore_path_mtu)
 627                 connp->conn_ixa->ixa_flags |= IXAF_PMTU_DISCOVERY;
 628 
 629         /* Use conn_lock to satify ASSERT; tcp is already serialized */
 630         mutex_enter(&connp->conn_lock);
 631         error = conn_connect(connp, &uinfo, flags);
 632         mutex_exit(&connp->conn_lock);
 633         if (error != 0)
 634                 return (error);
 635 
 636         error = tcp_build_hdrs(tcp);
 637         if (error != 0)
 638                 return (error);
 639 
 640         tcp->tcp_localnet = uinfo.iulp_localnet;
 641 
 642         if (uinfo.iulp_rtt != 0) {
 643                 clock_t rto;
 644 
 645                 tcp->tcp_rtt_sa = uinfo.iulp_rtt;
 646                 tcp->tcp_rtt_sd = uinfo.iulp_rtt_sd;
 647                 rto = (tcp->tcp_rtt_sa >> 3) + tcp->tcp_rtt_sd +
 648                     tcps->tcps_rexmit_interval_extra +
 649                     (tcp->tcp_rtt_sa >> 5);
 650 
 651                 TCP_SET_RTO(tcp, rto);
 652         }
 653         if (uinfo.iulp_ssthresh != 0)
 654                 tcp->tcp_cwnd_ssthresh = uinfo.iulp_ssthresh;
 655         else
 656                 tcp->tcp_cwnd_ssthresh = TCP_MAX_LARGEWIN;
 657         if (uinfo.iulp_spipe > 0) {
 658                 connp->conn_sndbuf = MIN(uinfo.iulp_spipe,
 659                     tcps->tcps_max_buf);
 660                 if (tcps->tcps_snd_lowat_fraction != 0) {
 661                         connp->conn_sndlowat = connp->conn_sndbuf /
 662                             tcps->tcps_snd_lowat_fraction;
 663                 }
 664                 (void) tcp_maxpsz_set(tcp, B_TRUE);
 665         }
 666         /*
 667          * Note that up till now, acceptor always inherits receive
 668          * window from the listener.  But if there is a metrics
 669          * associated with a host, we should use that instead of
 670          * inheriting it from listener. Thus we need to pass this
 671          * info back to the caller.
 672          */
 673         if (uinfo.iulp_rpipe > 0) {
 674                 tcp->tcp_rwnd = MIN(uinfo.iulp_rpipe,
 675                     tcps->tcps_max_buf);
 676         }
 677 
 678         if (uinfo.iulp_rtomax > 0) {
 679                 tcp->tcp_second_timer_threshold =
 680                     uinfo.iulp_rtomax;
 681         }
 682 
 683         /*
 684          * Use the metric option settings, iulp_tstamp_ok and
 685          * iulp_wscale_ok, only for active open. What this means
 686          * is that if the other side uses timestamp or window
 687          * scale option, TCP will also use those options. That
 688          * is for passive open.  If the application sets a
 689          * large window, window scale is enabled regardless of
 690          * the value in iulp_wscale_ok.  This is the behavior
 691          * since 2.6.  So we keep it.
 692          * The only case left in passive open processing is the
 693          * check for SACK.
 694          * For ECN, it should probably be like SACK.  But the
 695          * current value is binary, so we treat it like the other
 696          * cases.  The metric only controls active open.For passive
 697          * open, the ndd param, tcp_ecn_permitted, controls the
 698          * behavior.
 699          */
 700         if (!tcp_detached) {
 701                 /*
 702                  * The if check means that the following can only
 703                  * be turned on by the metrics only IRE, but not off.
 704                  */
 705                 if (uinfo.iulp_tstamp_ok)
 706                         tcp->tcp_snd_ts_ok = B_TRUE;
 707                 if (uinfo.iulp_wscale_ok)
 708                         tcp->tcp_snd_ws_ok = B_TRUE;
 709                 if (uinfo.iulp_sack == 2)
 710                         tcp->tcp_snd_sack_ok = B_TRUE;
 711                 if (uinfo.iulp_ecn_ok)
 712                         tcp->tcp_ecn_ok = B_TRUE;
 713         } else {
 714                 /*
 715                  * Passive open.
 716                  *
 717                  * As above, the if check means that SACK can only be
 718                  * turned on by the metric only IRE.
 719                  */
 720                 if (uinfo.iulp_sack > 0) {
 721                         tcp->tcp_snd_sack_ok = B_TRUE;
 722                 }
 723         }
 724 
 725         /*
 726          * XXX Note that currently, iulp_mtu can be as small as 68
 727          * because of PMTUd.  So tcp_mss may go to negative if combined
 728          * length of all those options exceeds 28 bytes.  But because
 729          * of the tcp_mss_min check below, we may not have a problem if
 730          * tcp_mss_min is of a reasonable value.  The default is 1 so
 731          * the negative problem still exists.  And the check defeats PMTUd.
 732          * In fact, if PMTUd finds that the MSS should be smaller than
 733          * tcp_mss_min, TCP should turn off PMUTd and use the tcp_mss_min
 734          * value.
 735          *
 736          * We do not deal with that now.  All those problems related to
 737          * PMTUd will be fixed later.
 738          */
 739         ASSERT(uinfo.iulp_mtu != 0);
 740         mss = tcp->tcp_initial_pmtu = uinfo.iulp_mtu;
 741 
 742         /* Sanity check for MSS value. */
 743         if (connp->conn_ipversion == IPV4_VERSION)
 744                 mss_max = tcps->tcps_mss_max_ipv4;
 745         else
 746                 mss_max = tcps->tcps_mss_max_ipv6;
 747 
 748         if (tcp->tcp_ipsec_overhead == 0)
 749                 tcp->tcp_ipsec_overhead = conn_ipsec_length(connp);
 750 
 751         mss -= tcp->tcp_ipsec_overhead;
 752 
 753         if (mss < tcps->tcps_mss_min)
 754                 mss = tcps->tcps_mss_min;
 755         if (mss > mss_max)
 756                 mss = mss_max;
 757 
 758         /* Note that this is the maximum MSS, excluding all options. */
 759         tcp->tcp_mss = mss;
 760 
 761         /*
 762          * Update the tcp connection with LSO capability.
 763          */
 764         tcp_update_lso(tcp, connp->conn_ixa);
 765 
 766         /*
 767          * Initialize the ISS here now that we have the full connection ID.
 768          * The RFC 1948 method of initial sequence number generation requires
 769          * knowledge of the full connection ID before setting the ISS.
 770          */
 771         tcp_iss_init(tcp);
 772 
 773         tcp->tcp_loopback = (uinfo.iulp_loopback | uinfo.iulp_local);
 774 
 775         /*
 776          * Make sure that conn is not marked incipient
 777          * for incoming connections. A blind
 778          * removal of incipient flag is cheaper than
 779          * check and removal.
 780          */
 781         mutex_enter(&connp->conn_lock);
 782         connp->conn_state_flags &= ~CONN_INCIPIENT;
 783         mutex_exit(&connp->conn_lock);
 784         return (0);
 785 }
 786 
 787 /*
 788  * tcp_clean_death / tcp_close_detached must not be called more than once
 789  * on a tcp. Thus every function that potentially calls tcp_clean_death
 790  * must check for the tcp state before calling tcp_clean_death.
 791  * Eg. tcp_input_data, tcp_eager_kill, tcp_clean_death_wrapper,
 792  * tcp_timer_handler, all check for the tcp state.
 793  */
 794 /* ARGSUSED */
 795 void
 796 tcp_clean_death_wrapper(void *arg, mblk_t *mp, void *arg2,
 797     ip_recv_attr_t *dummy)
 798 {
 799         tcp_t   *tcp = ((conn_t *)arg)->conn_tcp;
 800 
 801         freemsg(mp);
 802         if (tcp->tcp_state > TCPS_BOUND)
 803                 (void) tcp_clean_death(((conn_t *)arg)->conn_tcp, ETIMEDOUT);
 804 }
 805 
 806 /*
 807  * We are dying for some reason.  Try to do it gracefully.  (May be called
 808  * as writer.)
 809  *
 810  * Return -1 if the structure was not cleaned up (if the cleanup had to be
 811  * done by a service procedure).
 812  * TBD - Should the return value distinguish between the tcp_t being
 813  * freed and it being reinitialized?
 814  */
 815 int
 816 tcp_clean_death(tcp_t *tcp, int err)
 817 {
 818         mblk_t  *mp;
 819         queue_t *q;
 820         conn_t  *connp = tcp->tcp_connp;
 821         tcp_stack_t     *tcps = tcp->tcp_tcps;
 822 
 823         if (tcp->tcp_fused)
 824                 tcp_unfuse(tcp);
 825 
 826         if (tcp->tcp_linger_tid != 0 &&
 827             TCP_TIMER_CANCEL(tcp, tcp->tcp_linger_tid) >= 0) {
 828                 tcp_stop_lingering(tcp);
 829         }
 830 
 831         ASSERT(tcp != NULL);
 832         ASSERT((connp->conn_family == AF_INET &&
 833             connp->conn_ipversion == IPV4_VERSION) ||
 834             (connp->conn_family == AF_INET6 &&
 835             (connp->conn_ipversion == IPV4_VERSION ||
 836             connp->conn_ipversion == IPV6_VERSION)));
 837 
 838         if (TCP_IS_DETACHED(tcp)) {
 839                 if (tcp->tcp_hard_binding) {
 840                         /*
 841                          * Its an eager that we are dealing with. We close the
 842                          * eager but in case a conn_ind has already gone to the
 843                          * listener, let tcp_accept_finish() send a discon_ind
 844                          * to the listener and drop the last reference. If the
 845                          * listener doesn't even know about the eager i.e. the
 846                          * conn_ind hasn't gone up, blow away the eager and drop
 847                          * the last reference as well. If the conn_ind has gone
 848                          * up, state should be BOUND. tcp_accept_finish
 849                          * will figure out that the connection has received a
 850                          * RST and will send a DISCON_IND to the application.
 851                          */
 852                         tcp_closei_local(tcp);
 853                         if (!tcp->tcp_tconnind_started) {
 854                                 CONN_DEC_REF(connp);
 855                         } else {
 856                                 tcp->tcp_state = TCPS_BOUND;
 857                                 DTRACE_TCP6(state__change, void, NULL,
 858                                     ip_xmit_attr_t *, connp->conn_ixa,
 859                                     void, NULL, tcp_t *, tcp, void, NULL,
 860                                     int32_t, TCPS_CLOSED);
 861                         }
 862                 } else {
 863                         tcp_close_detached(tcp);
 864                 }
 865                 return (0);
 866         }
 867 
 868         TCP_STAT(tcps, tcp_clean_death_nondetached);
 869 
 870         /*
 871          * The connection is dead.  Decrement listener connection counter if
 872          * necessary.
 873          */
 874         if (tcp->tcp_listen_cnt != NULL)
 875                 TCP_DECR_LISTEN_CNT(tcp);
 876 
 877         /*
 878          * When a connection is moved to TIME_WAIT state, the connection
 879          * counter is already decremented.  So no need to decrement here
 880          * again.  See SET_TIME_WAIT() macro.
 881          */
 882         if (tcp->tcp_state >= TCPS_ESTABLISHED &&
 883             tcp->tcp_state < TCPS_TIME_WAIT) {
 884                 TCPS_CONN_DEC(tcps);
 885         }
 886 
 887         q = connp->conn_rq;
 888 
 889         /* Trash all inbound data */
 890         if (!IPCL_IS_NONSTR(connp)) {
 891                 ASSERT(q != NULL);
 892                 flushq(q, FLUSHALL);
 893         }
 894 
 895         /*
 896          * If we are at least part way open and there is error
 897          * (err==0 implies no error)
 898          * notify our client by a T_DISCON_IND.
 899          */
 900         if ((tcp->tcp_state >= TCPS_SYN_SENT) && err) {
 901                 if (tcp->tcp_state >= TCPS_ESTABLISHED &&
 902                     !TCP_IS_SOCKET(tcp)) {
 903                         /*
 904                          * Send M_FLUSH according to TPI. Because sockets will
 905                          * (and must) ignore FLUSHR we do that only for TPI
 906                          * endpoints and sockets in STREAMS mode.
 907                          */
 908                         (void) putnextctl1(q, M_FLUSH, FLUSHR);
 909                 }
 910                 if (connp->conn_debug) {
 911                         (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE|SL_ERROR,
 912                             "tcp_clean_death: discon err %d", err);
 913                 }
 914                 if (IPCL_IS_NONSTR(connp)) {
 915                         /* Direct socket, use upcall */
 916                         (*connp->conn_upcalls->su_disconnected)(
 917                             connp->conn_upper_handle, tcp->tcp_connid, err);
 918                 } else {
 919                         mp = mi_tpi_discon_ind(NULL, err, 0);
 920                         if (mp != NULL) {
 921                                 putnext(q, mp);
 922                         } else {
 923                                 if (connp->conn_debug) {
 924                                         (void) strlog(TCP_MOD_ID, 0, 1,
 925                                             SL_ERROR|SL_TRACE,
 926                                             "tcp_clean_death, sending M_ERROR");
 927                                 }
 928                                 (void) putnextctl1(q, M_ERROR, EPROTO);
 929                         }
 930                 }
 931                 if (tcp->tcp_state <= TCPS_SYN_RCVD) {
 932                         /* SYN_SENT or SYN_RCVD */
 933                         TCPS_BUMP_MIB(tcps, tcpAttemptFails);
 934                 } else if (tcp->tcp_state <= TCPS_CLOSE_WAIT) {
 935                         /* ESTABLISHED or CLOSE_WAIT */
 936                         TCPS_BUMP_MIB(tcps, tcpEstabResets);
 937                 }
 938         }
 939 
 940         /*
 941          * ESTABLISHED non-STREAMS eagers are not 'detached' because
 942          * an upper handle is obtained when the SYN-ACK comes in. So it
 943          * should receive the 'disconnected' upcall, but tcp_reinit should
 944          * not be called since this is an eager.
 945          */
 946         if (tcp->tcp_listener != NULL && IPCL_IS_NONSTR(connp)) {
 947                 tcp_closei_local(tcp);
 948                 tcp->tcp_state = TCPS_BOUND;
 949                 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
 950                     connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
 951                     int32_t, TCPS_CLOSED);
 952                 return (0);
 953         }
 954 
 955         tcp_reinit(tcp);
 956         if (IPCL_IS_NONSTR(connp))
 957                 (void) tcp_do_unbind(connp);
 958 
 959         return (-1);
 960 }
 961 
 962 /*
 963  * In case tcp is in the "lingering state" and waits for the SO_LINGER timeout
 964  * to expire, stop the wait and finish the close.
 965  */
 966 void
 967 tcp_stop_lingering(tcp_t *tcp)
 968 {
 969         clock_t delta = 0;
 970         tcp_stack_t     *tcps = tcp->tcp_tcps;
 971         conn_t          *connp = tcp->tcp_connp;
 972 
 973         tcp->tcp_linger_tid = 0;
 974         if (tcp->tcp_state > TCPS_LISTEN) {
 975                 tcp_acceptor_hash_remove(tcp);
 976                 mutex_enter(&tcp->tcp_non_sq_lock);
 977                 if (tcp->tcp_flow_stopped) {
 978                         tcp_clrqfull(tcp);
 979                 }
 980                 mutex_exit(&tcp->tcp_non_sq_lock);
 981 
 982                 if (tcp->tcp_timer_tid != 0) {
 983                         delta = TCP_TIMER_CANCEL(tcp, tcp->tcp_timer_tid);
 984                         tcp->tcp_timer_tid = 0;
 985                 }
 986                 /*
 987                  * Need to cancel those timers which will not be used when
 988                  * TCP is detached.  This has to be done before the conn_wq
 989                  * is cleared.
 990                  */
 991                 tcp_timers_stop(tcp);
 992 
 993                 tcp->tcp_detached = B_TRUE;
 994                 connp->conn_rq = NULL;
 995                 connp->conn_wq = NULL;
 996 
 997                 if (tcp->tcp_state == TCPS_TIME_WAIT) {
 998                         tcp_time_wait_append(tcp);
 999                         TCP_DBGSTAT(tcps, tcp_detach_time_wait);
1000                         goto finish;
1001                 }
1002 
1003                 /*
1004                  * If delta is zero the timer event wasn't executed and was
1005                  * successfully canceled. In this case we need to restart it
1006                  * with the minimal delta possible.
1007                  */
1008                 if (delta >= 0) {
1009                         tcp->tcp_timer_tid = TCP_TIMER(tcp, tcp_timer,
1010                             delta ? delta : 1);
1011                 }
1012         } else {
1013                 tcp_closei_local(tcp);
1014                 CONN_DEC_REF(connp);
1015         }
1016 finish:
1017         tcp->tcp_detached = B_TRUE;
1018         connp->conn_rq = NULL;
1019         connp->conn_wq = NULL;
1020 
1021         /* Signal closing thread that it can complete close */
1022         mutex_enter(&tcp->tcp_closelock);
1023         tcp->tcp_closed = 1;
1024         cv_signal(&tcp->tcp_closecv);
1025         mutex_exit(&tcp->tcp_closelock);
1026 
1027         /* If we have an upper handle (socket), release it */
1028         if (IPCL_IS_NONSTR(connp)) {
1029                 ASSERT(connp->conn_upper_handle != NULL);
1030                 (*connp->conn_upcalls->su_closed)(connp->conn_upper_handle);
1031                 connp->conn_upper_handle = NULL;
1032                 connp->conn_upcalls = NULL;
1033         }
1034 }
1035 
1036 void
1037 tcp_close_common(conn_t *connp, int flags)
1038 {
1039         tcp_t           *tcp = connp->conn_tcp;
1040         mblk_t          *mp = &tcp->tcp_closemp;
1041         boolean_t       conn_ioctl_cleanup_reqd = B_FALSE;
1042         mblk_t          *bp;
1043 
1044         ASSERT(connp->conn_ref >= 2);
1045 
1046         /*
1047          * Mark the conn as closing. ipsq_pending_mp_add will not
1048          * add any mp to the pending mp list, after this conn has
1049          * started closing.
1050          */
1051         mutex_enter(&connp->conn_lock);
1052         connp->conn_state_flags |= CONN_CLOSING;
1053         if (connp->conn_oper_pending_ill != NULL)
1054                 conn_ioctl_cleanup_reqd = B_TRUE;
1055         CONN_INC_REF_LOCKED(connp);
1056         mutex_exit(&connp->conn_lock);
1057         tcp->tcp_closeflags = (uint8_t)flags;
1058         ASSERT(connp->conn_ref >= 3);
1059 
1060         /*
1061          * tcp_closemp_used is used below without any protection of a lock
1062          * as we don't expect any one else to use it concurrently at this
1063          * point otherwise it would be a major defect.
1064          */
1065 
1066         if (mp->b_prev == NULL)
1067                 tcp->tcp_closemp_used = B_TRUE;
1068         else
1069                 cmn_err(CE_PANIC, "tcp_close: concurrent use of tcp_closemp: "
1070                     "connp %p tcp %p\n", (void *)connp, (void *)tcp);
1071 
1072         TCP_DEBUG_GETPCSTACK(tcp->tcmp_stk, 15);
1073 
1074         /*
1075          * Cleanup any queued ioctls here. This must be done before the wq/rq
1076          * are re-written by tcp_close_output().
1077          */
1078         if (conn_ioctl_cleanup_reqd)
1079                 conn_ioctl_cleanup(connp);
1080 
1081         /*
1082          * As CONN_CLOSING is set, no further ioctls should be passed down to
1083          * IP for this conn (see the guards in tcp_ioctl, tcp_wput_ioctl and
1084          * tcp_wput_iocdata). If the ioctl was queued on an ipsq,
1085          * conn_ioctl_cleanup should have found it and removed it. If the ioctl
1086          * was still in flight at the time, we wait for it here. See comments
1087          * for CONN_INC_IOCTLREF in ip.h for details.
1088          */
1089         mutex_enter(&connp->conn_lock);
1090         while (connp->conn_ioctlref > 0)
1091                 cv_wait(&connp->conn_cv, &connp->conn_lock);
1092         ASSERT(connp->conn_ioctlref == 0);
1093         ASSERT(connp->conn_oper_pending_ill == NULL);
1094         mutex_exit(&connp->conn_lock);
1095 
1096         SQUEUE_ENTER_ONE(connp->conn_sqp, mp, tcp_close_output, connp,
1097             NULL, tcp_squeue_flag, SQTAG_IP_TCP_CLOSE);
1098 
1099         /*
1100          * For non-STREAMS sockets, the normal case is that the conn makes
1101          * an upcall when it's finally closed, so there is no need to wait
1102          * in the protocol. But in case of SO_LINGER the thread sleeps here
1103          * so it can properly deal with the thread being interrupted.
1104          */
1105         if (IPCL_IS_NONSTR(connp) && connp->conn_linger == 0)
1106                 goto nowait;
1107 
1108         mutex_enter(&tcp->tcp_closelock);
1109         while (!tcp->tcp_closed) {
1110                 if (!cv_wait_sig(&tcp->tcp_closecv, &tcp->tcp_closelock)) {
1111                         /*
1112                          * The cv_wait_sig() was interrupted. We now do the
1113                          * following:
1114                          *
1115                          * 1) If the endpoint was lingering, we allow this
1116                          * to be interrupted by cancelling the linger timeout
1117                          * and closing normally.
1118                          *
1119                          * 2) Revert to calling cv_wait()
1120                          *
1121                          * We revert to using cv_wait() to avoid an
1122                          * infinite loop which can occur if the calling
1123                          * thread is higher priority than the squeue worker
1124                          * thread and is bound to the same cpu.
1125                          */
1126                         if (connp->conn_linger && connp->conn_lingertime > 0) {
1127                                 mutex_exit(&tcp->tcp_closelock);
1128                                 /* Entering squeue, bump ref count. */
1129                                 CONN_INC_REF(connp);
1130                                 bp = allocb_wait(0, BPRI_HI, STR_NOSIG, NULL);
1131                                 SQUEUE_ENTER_ONE(connp->conn_sqp, bp,
1132                                     tcp_linger_interrupted, connp, NULL,
1133                                     tcp_squeue_flag, SQTAG_IP_TCP_CLOSE);
1134                                 mutex_enter(&tcp->tcp_closelock);
1135                         }
1136                         break;
1137                 }
1138         }
1139         while (!tcp->tcp_closed)
1140                 cv_wait(&tcp->tcp_closecv, &tcp->tcp_closelock);
1141         mutex_exit(&tcp->tcp_closelock);
1142 
1143         /*
1144          * In the case of listener streams that have eagers in the q or q0
1145          * we wait for the eagers to drop their reference to us. conn_rq and
1146          * conn_wq of the eagers point to our queues. By waiting for the
1147          * refcnt to drop to 1, we are sure that the eagers have cleaned
1148          * up their queue pointers and also dropped their references to us.
1149          *
1150          * For non-STREAMS sockets we do not have to wait here; the
1151          * listener will instead make a su_closed upcall when the last
1152          * reference is dropped.
1153          */
1154         if (tcp->tcp_wait_for_eagers && !IPCL_IS_NONSTR(connp)) {
1155                 mutex_enter(&connp->conn_lock);
1156                 while (connp->conn_ref != 1) {
1157                         cv_wait(&connp->conn_cv, &connp->conn_lock);
1158                 }
1159                 mutex_exit(&connp->conn_lock);
1160         }
1161 
1162 nowait:
1163         connp->conn_cpid = NOPID;
1164 }
1165 
1166 /*
1167  * Called by tcp_close() routine via squeue when lingering is
1168  * interrupted by a signal.
1169  */
1170 
1171 /* ARGSUSED */
1172 static void
1173 tcp_linger_interrupted(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1174 {
1175         conn_t  *connp = (conn_t *)arg;
1176         tcp_t   *tcp = connp->conn_tcp;
1177 
1178         freeb(mp);
1179         if (tcp->tcp_linger_tid != 0 &&
1180             TCP_TIMER_CANCEL(tcp, tcp->tcp_linger_tid) >= 0) {
1181                 tcp_stop_lingering(tcp);
1182                 tcp->tcp_client_errno = EINTR;
1183         }
1184 }
1185 
1186 /*
1187  * Clean up the b_next and b_prev fields of every mblk pointed at by *mpp.
1188  * Some stream heads get upset if they see these later on as anything but NULL.
1189  */
1190 void
1191 tcp_close_mpp(mblk_t **mpp)
1192 {
1193         mblk_t  *mp;
1194 
1195         if ((mp = *mpp) != NULL) {
1196                 do {
1197                         mp->b_next = NULL;
1198                         mp->b_prev = NULL;
1199                 } while ((mp = mp->b_cont) != NULL);
1200 
1201                 mp = *mpp;
1202                 *mpp = NULL;
1203                 freemsg(mp);
1204         }
1205 }
1206 
1207 /* Do detached close. */
1208 void
1209 tcp_close_detached(tcp_t *tcp)
1210 {
1211         if (tcp->tcp_fused)
1212                 tcp_unfuse(tcp);
1213 
1214         /*
1215          * Clustering code serializes TCP disconnect callbacks and
1216          * cluster tcp list walks by blocking a TCP disconnect callback
1217          * if a cluster tcp list walk is in progress. This ensures
1218          * accurate accounting of TCPs in the cluster code even though
1219          * the TCP list walk itself is not atomic.
1220          */
1221         tcp_closei_local(tcp);
1222         CONN_DEC_REF(tcp->tcp_connp);
1223 }
1224 
1225 /*
1226  * The tcp_t is going away. Remove it from all lists and set it
1227  * to TCPS_CLOSED. The freeing up of memory is deferred until
1228  * tcp_inactive. This is needed since a thread in tcp_rput might have
1229  * done a CONN_INC_REF on this structure before it was removed from the
1230  * hashes.
1231  */
1232 void
1233 tcp_closei_local(tcp_t *tcp)
1234 {
1235         conn_t          *connp = tcp->tcp_connp;
1236         tcp_stack_t     *tcps = tcp->tcp_tcps;
1237         int32_t         oldstate;
1238 
1239         if (!TCP_IS_SOCKET(tcp))
1240                 tcp_acceptor_hash_remove(tcp);
1241 
1242         TCPS_UPDATE_MIB(tcps, tcpHCInSegs, tcp->tcp_ibsegs);
1243         tcp->tcp_ibsegs = 0;
1244         TCPS_UPDATE_MIB(tcps, tcpHCOutSegs, tcp->tcp_obsegs);
1245         tcp->tcp_obsegs = 0;
1246 
1247         /*
1248          * This can be called via tcp_time_wait_processing() if TCP gets a
1249          * SYN with sequence number outside the TIME-WAIT connection's
1250          * window.  So we need to check for TIME-WAIT state here as the
1251          * connection counter is already decremented.  See SET_TIME_WAIT()
1252          * macro
1253          */
1254         if (tcp->tcp_state >= TCPS_ESTABLISHED &&
1255             tcp->tcp_state < TCPS_TIME_WAIT) {
1256                 TCPS_CONN_DEC(tcps);
1257         }
1258 
1259         /*
1260          * If we are an eager connection hanging off a listener that
1261          * hasn't formally accepted the connection yet, get off its
1262          * list and blow off any data that we have accumulated.
1263          */
1264         if (tcp->tcp_listener != NULL) {
1265                 tcp_t   *listener = tcp->tcp_listener;
1266                 mutex_enter(&listener->tcp_eager_lock);
1267                 /*
1268                  * tcp_tconnind_started == B_TRUE means that the
1269                  * conn_ind has already gone to listener. At
1270                  * this point, eager will be closed but we
1271                  * leave it in listeners eager list so that
1272                  * if listener decides to close without doing
1273                  * accept, we can clean this up. In tcp_tli_accept
1274                  * we take care of the case of accept on closed
1275                  * eager.
1276                  */
1277                 if (!tcp->tcp_tconnind_started) {
1278                         tcp_eager_unlink(tcp);
1279                         mutex_exit(&listener->tcp_eager_lock);
1280                         /*
1281                          * We don't want to have any pointers to the
1282                          * listener queue, after we have released our
1283                          * reference on the listener
1284                          */
1285                         ASSERT(tcp->tcp_detached);
1286                         connp->conn_rq = NULL;
1287                         connp->conn_wq = NULL;
1288                         CONN_DEC_REF(listener->tcp_connp);
1289                 } else {
1290                         mutex_exit(&listener->tcp_eager_lock);
1291                 }
1292         }
1293 
1294         /* Stop all the timers */
1295         tcp_timers_stop(tcp);
1296 
1297         if (tcp->tcp_state == TCPS_LISTEN) {
1298                 if (tcp->tcp_ip_addr_cache) {
1299                         kmem_free((void *)tcp->tcp_ip_addr_cache,
1300                             IP_ADDR_CACHE_SIZE * sizeof (ipaddr_t));
1301                         tcp->tcp_ip_addr_cache = NULL;
1302                 }
1303         }
1304 
1305         /* Decrement listerner connection counter if necessary. */
1306         if (tcp->tcp_listen_cnt != NULL)
1307                 TCP_DECR_LISTEN_CNT(tcp);
1308 
1309         mutex_enter(&tcp->tcp_non_sq_lock);
1310         if (tcp->tcp_flow_stopped)
1311                 tcp_clrqfull(tcp);
1312         mutex_exit(&tcp->tcp_non_sq_lock);
1313 
1314         tcp_bind_hash_remove(tcp);
1315         /*
1316          * If the tcp_time_wait_collector (which runs outside the squeue)
1317          * is trying to remove this tcp from the time wait list, we will
1318          * block in tcp_time_wait_remove while trying to acquire the
1319          * tcp_time_wait_lock. The logic in tcp_time_wait_collector also
1320          * requires the ipcl_hash_remove to be ordered after the
1321          * tcp_time_wait_remove for the refcnt checks to work correctly.
1322          */
1323         if (tcp->tcp_state == TCPS_TIME_WAIT)
1324                 (void) tcp_time_wait_remove(tcp, NULL);
1325         CL_INET_DISCONNECT(connp);
1326         ipcl_hash_remove(connp);
1327         oldstate = tcp->tcp_state;
1328         tcp->tcp_state = TCPS_CLOSED;
1329         /* Need to probe before ixa_cleanup() is called */
1330         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
1331             connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
1332             int32_t, oldstate);
1333         ixa_cleanup(connp->conn_ixa);
1334 
1335         /*
1336          * Mark the conn as CONDEMNED
1337          */
1338         mutex_enter(&connp->conn_lock);
1339         connp->conn_state_flags |= CONN_CONDEMNED;
1340         mutex_exit(&connp->conn_lock);
1341 
1342         ASSERT(tcp->tcp_time_wait_next == NULL);
1343         ASSERT(tcp->tcp_time_wait_prev == NULL);
1344         ASSERT(tcp->tcp_time_wait_expire == 0);
1345 
1346         tcp_ipsec_cleanup(tcp);
1347 }
1348 
1349 /*
1350  * tcp is dying (called from ipcl_conn_destroy and error cases).
1351  * Free the tcp_t in either case.
1352  */
1353 void
1354 tcp_free(tcp_t *tcp)
1355 {
1356         mblk_t          *mp;
1357         conn_t          *connp = tcp->tcp_connp;
1358 
1359         ASSERT(tcp != NULL);
1360         ASSERT(tcp->tcp_ptpahn == NULL && tcp->tcp_acceptor_hash == NULL);
1361 
1362         connp->conn_rq = NULL;
1363         connp->conn_wq = NULL;
1364 
1365         tcp_close_mpp(&tcp->tcp_xmit_head);
1366         tcp_close_mpp(&tcp->tcp_reass_head);
1367         if (tcp->tcp_rcv_list != NULL) {
1368                 /* Free b_next chain */
1369                 tcp_close_mpp(&tcp->tcp_rcv_list);
1370         }
1371         if ((mp = tcp->tcp_urp_mp) != NULL) {
1372                 freemsg(mp);
1373         }
1374         if ((mp = tcp->tcp_urp_mark_mp) != NULL) {
1375                 freemsg(mp);
1376         }
1377 
1378         if (tcp->tcp_fused_sigurg_mp != NULL) {
1379                 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
1380                 freeb(tcp->tcp_fused_sigurg_mp);
1381                 tcp->tcp_fused_sigurg_mp = NULL;
1382         }
1383 
1384         if (tcp->tcp_ordrel_mp != NULL) {
1385                 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
1386                 freeb(tcp->tcp_ordrel_mp);
1387                 tcp->tcp_ordrel_mp = NULL;
1388         }
1389 
1390         TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list, tcp);
1391         bzero(&tcp->tcp_sack_info, sizeof (tcp_sack_info_t));
1392 
1393         if (tcp->tcp_hopopts != NULL) {
1394                 mi_free(tcp->tcp_hopopts);
1395                 tcp->tcp_hopopts = NULL;
1396                 tcp->tcp_hopoptslen = 0;
1397         }
1398         ASSERT(tcp->tcp_hopoptslen == 0);
1399         if (tcp->tcp_dstopts != NULL) {
1400                 mi_free(tcp->tcp_dstopts);
1401                 tcp->tcp_dstopts = NULL;
1402                 tcp->tcp_dstoptslen = 0;
1403         }
1404         ASSERT(tcp->tcp_dstoptslen == 0);
1405         if (tcp->tcp_rthdrdstopts != NULL) {
1406                 mi_free(tcp->tcp_rthdrdstopts);
1407                 tcp->tcp_rthdrdstopts = NULL;
1408                 tcp->tcp_rthdrdstoptslen = 0;
1409         }
1410         ASSERT(tcp->tcp_rthdrdstoptslen == 0);
1411         if (tcp->tcp_rthdr != NULL) {
1412                 mi_free(tcp->tcp_rthdr);
1413                 tcp->tcp_rthdr = NULL;
1414                 tcp->tcp_rthdrlen = 0;
1415         }
1416         ASSERT(tcp->tcp_rthdrlen == 0);
1417 
1418         /*
1419          * Following is really a blowing away a union.
1420          * It happens to have exactly two members of identical size
1421          * the following code is enough.
1422          */
1423         tcp_close_mpp(&tcp->tcp_conn.tcp_eager_conn_ind);
1424 
1425         /*
1426          * If this is a non-STREAM socket still holding on to an upper
1427          * handle, release it. As a result of fallback we might also see
1428          * STREAMS based conns with upper handles, in which case there is
1429          * nothing to do other than clearing the field.
1430          */
1431         if (connp->conn_upper_handle != NULL) {
1432                 if (IPCL_IS_NONSTR(connp)) {
1433                         (*connp->conn_upcalls->su_closed)(
1434                             connp->conn_upper_handle);
1435                         tcp->tcp_detached = B_TRUE;
1436                 }
1437                 connp->conn_upper_handle = NULL;
1438                 connp->conn_upcalls = NULL;
1439         }
1440 }
1441 
1442 /*
1443  * tcp_get_conn/tcp_free_conn
1444  *
1445  * tcp_get_conn is used to get a clean tcp connection structure.
1446  * It tries to reuse the connections put on the freelist by the
1447  * time_wait_collector failing which it goes to kmem_cache. This
1448  * way has two benefits compared to just allocating from and
1449  * freeing to kmem_cache.
1450  * 1) The time_wait_collector can free (which includes the cleanup)
1451  * outside the squeue. So when the interrupt comes, we have a clean
1452  * connection sitting in the freelist. Obviously, this buys us
1453  * performance.
1454  *
1455  * 2) Defence against DOS attack. Allocating a tcp/conn in tcp_input_listener
1456  * has multiple disadvantages - tying up the squeue during alloc.
1457  * But allocating the conn/tcp in IP land is also not the best since
1458  * we can't check the 'q' and 'q0' which are protected by squeue and
1459  * blindly allocate memory which might have to be freed here if we are
1460  * not allowed to accept the connection. By using the freelist and
1461  * putting the conn/tcp back in freelist, we don't pay a penalty for
1462  * allocating memory without checking 'q/q0' and freeing it if we can't
1463  * accept the connection.
1464  *
1465  * Care should be taken to put the conn back in the same squeue's freelist
1466  * from which it was allocated. Best results are obtained if conn is
1467  * allocated from listener's squeue and freed to the same. Time wait
1468  * collector will free up the freelist is the connection ends up sitting
1469  * there for too long.
1470  */
1471 void *
1472 tcp_get_conn(void *arg, tcp_stack_t *tcps)
1473 {
1474         tcp_t                   *tcp = NULL;
1475         conn_t                  *connp = NULL;
1476         squeue_t                *sqp = (squeue_t *)arg;
1477         tcp_squeue_priv_t       *tcp_time_wait;
1478         netstack_t              *ns;
1479         mblk_t                  *tcp_rsrv_mp = NULL;
1480 
1481         tcp_time_wait =
1482             *((tcp_squeue_priv_t **)squeue_getprivate(sqp, SQPRIVATE_TCP));
1483 
1484         mutex_enter(&tcp_time_wait->tcp_time_wait_lock);
1485         tcp = tcp_time_wait->tcp_free_list;
1486         ASSERT((tcp != NULL) ^ (tcp_time_wait->tcp_free_list_cnt == 0));
1487         if (tcp != NULL) {
1488                 tcp_time_wait->tcp_free_list = tcp->tcp_time_wait_next;
1489                 tcp_time_wait->tcp_free_list_cnt--;
1490                 mutex_exit(&tcp_time_wait->tcp_time_wait_lock);
1491                 tcp->tcp_time_wait_next = NULL;
1492                 connp = tcp->tcp_connp;
1493                 connp->conn_flags |= IPCL_REUSED;
1494 
1495                 ASSERT(tcp->tcp_tcps == NULL);
1496                 ASSERT(connp->conn_netstack == NULL);
1497                 ASSERT(tcp->tcp_rsrv_mp != NULL);
1498                 ns = tcps->tcps_netstack;
1499                 netstack_hold(ns);
1500                 connp->conn_netstack = ns;
1501                 connp->conn_ixa->ixa_ipst = ns->netstack_ip;
1502                 tcp->tcp_tcps = tcps;
1503                 ipcl_globalhash_insert(connp);
1504 
1505                 connp->conn_ixa->ixa_notify_cookie = tcp;
1506                 ASSERT(connp->conn_ixa->ixa_notify == tcp_notify);
1507                 connp->conn_recv = tcp_input_data;
1508                 ASSERT(connp->conn_recvicmp == tcp_icmp_input);
1509                 ASSERT(connp->conn_verifyicmp == tcp_verifyicmp);
1510                 return ((void *)connp);
1511         }
1512         mutex_exit(&tcp_time_wait->tcp_time_wait_lock);
1513         /*
1514          * Pre-allocate the tcp_rsrv_mp. This mblk will not be freed until
1515          * this conn_t/tcp_t is freed at ipcl_conn_destroy().
1516          */
1517         tcp_rsrv_mp = allocb(0, BPRI_HI);
1518         if (tcp_rsrv_mp == NULL)
1519                 return (NULL);
1520 
1521         if ((connp = ipcl_conn_create(IPCL_TCPCONN, KM_NOSLEEP,
1522             tcps->tcps_netstack)) == NULL) {
1523                 freeb(tcp_rsrv_mp);
1524                 return (NULL);
1525         }
1526 
1527         tcp = connp->conn_tcp;
1528         tcp->tcp_rsrv_mp = tcp_rsrv_mp;
1529         mutex_init(&tcp->tcp_rsrv_mp_lock, NULL, MUTEX_DEFAULT, NULL);
1530 
1531         tcp->tcp_tcps = tcps;
1532 
1533         connp->conn_recv = tcp_input_data;
1534         connp->conn_recvicmp = tcp_icmp_input;
1535         connp->conn_verifyicmp = tcp_verifyicmp;
1536 
1537         /*
1538          * Register tcp_notify to listen to capability changes detected by IP.
1539          * This upcall is made in the context of the call to conn_ip_output
1540          * thus it is inside the squeue.
1541          */
1542         connp->conn_ixa->ixa_notify = tcp_notify;
1543         connp->conn_ixa->ixa_notify_cookie = tcp;
1544 
1545         return ((void *)connp);
1546 }
1547 
1548 /*
1549  * Handle connect to IPv4 destinations, including connections for AF_INET6
1550  * sockets connecting to IPv4 mapped IPv6 destinations.
1551  * Returns zero if OK, a positive errno, or a negative TLI error.
1552  */
1553 static int
1554 tcp_connect_ipv4(tcp_t *tcp, ipaddr_t *dstaddrp, in_port_t dstport,
1555     uint_t srcid)
1556 {
1557         ipaddr_t        dstaddr = *dstaddrp;
1558         uint16_t        lport;
1559         conn_t          *connp = tcp->tcp_connp;
1560         tcp_stack_t     *tcps = tcp->tcp_tcps;
1561         int             error;
1562 
1563         ASSERT(connp->conn_ipversion == IPV4_VERSION);
1564 
1565         /* Check for attempt to connect to INADDR_ANY */
1566         if (dstaddr == INADDR_ANY)  {
1567                 /*
1568                  * SunOS 4.x and 4.3 BSD allow an application
1569                  * to connect a TCP socket to INADDR_ANY.
1570                  * When they do this, the kernel picks the
1571                  * address of one interface and uses it
1572                  * instead.  The kernel usually ends up
1573                  * picking the address of the loopback
1574                  * interface.  This is an undocumented feature.
1575                  * However, we provide the same thing here
1576                  * in order to have source and binary
1577                  * compatibility with SunOS 4.x.
1578                  * Update the T_CONN_REQ (sin/sin6) since it is used to
1579                  * generate the T_CONN_CON.
1580                  */
1581                 dstaddr = htonl(INADDR_LOOPBACK);
1582                 *dstaddrp = dstaddr;
1583         }
1584 
1585         /* Handle __sin6_src_id if socket not bound to an IP address */
1586         if (srcid != 0 && connp->conn_laddr_v4 == INADDR_ANY) {
1587                 if (!ip_srcid_find_id(srcid, &connp->conn_laddr_v6,
1588                     IPCL_ZONEID(connp), B_TRUE, tcps->tcps_netstack)) {
1589                         /* Mismatch - conn_laddr_v6 would be v6 address. */
1590                         return (EADDRNOTAVAIL);
1591                 }
1592                 connp->conn_saddr_v6 = connp->conn_laddr_v6;
1593         }
1594 
1595         IN6_IPADDR_TO_V4MAPPED(dstaddr, &connp->conn_faddr_v6);
1596         connp->conn_fport = dstport;
1597 
1598         /*
1599          * At this point the remote destination address and remote port fields
1600          * in the tcp-four-tuple have been filled in the tcp structure. Now we
1601          * have to see which state tcp was in so we can take appropriate action.
1602          */
1603         if (tcp->tcp_state == TCPS_IDLE) {
1604                 /*
1605                  * We support a quick connect capability here, allowing
1606                  * clients to transition directly from IDLE to SYN_SENT
1607                  * tcp_bindi will pick an unused port, insert the connection
1608                  * in the bind hash and transition to BOUND state.
1609                  */
1610                 lport = tcp_update_next_port(tcps->tcps_next_port_to_try,
1611                     tcp, B_TRUE);
1612                 lport = tcp_bindi(tcp, lport, &connp->conn_laddr_v6, 0, B_TRUE,
1613                     B_FALSE, B_FALSE);
1614                 if (lport == 0)
1615                         return (-TNOADDR);
1616         }
1617 
1618         /*
1619          * Lookup the route to determine a source address and the uinfo.
1620          * Setup TCP parameters based on the metrics/DCE.
1621          */
1622         error = tcp_set_destination(tcp);
1623         if (error != 0)
1624                 return (error);
1625 
1626         /*
1627          * Don't let an endpoint connect to itself.
1628          */
1629         if (connp->conn_faddr_v4 == connp->conn_laddr_v4 &&
1630             connp->conn_fport == connp->conn_lport)
1631                 return (-TBADADDR);
1632 
1633         tcp->tcp_state = TCPS_SYN_SENT;
1634 
1635         return (ipcl_conn_insert_v4(connp));
1636 }
1637 
1638 /*
1639  * Handle connect to IPv6 destinations.
1640  * Returns zero if OK, a positive errno, or a negative TLI error.
1641  */
1642 static int
1643 tcp_connect_ipv6(tcp_t *tcp, in6_addr_t *dstaddrp, in_port_t dstport,
1644     uint32_t flowinfo, uint_t srcid, uint32_t scope_id)
1645 {
1646         uint16_t        lport;
1647         conn_t          *connp = tcp->tcp_connp;
1648         tcp_stack_t     *tcps = tcp->tcp_tcps;
1649         int             error;
1650 
1651         ASSERT(connp->conn_family == AF_INET6);
1652 
1653         /*
1654          * If we're here, it means that the destination address is a native
1655          * IPv6 address.  Return an error if conn_ipversion is not IPv6.  A
1656          * reason why it might not be IPv6 is if the socket was bound to an
1657          * IPv4-mapped IPv6 address.
1658          */
1659         if (connp->conn_ipversion != IPV6_VERSION)
1660                 return (-TBADADDR);
1661 
1662         /*
1663          * Interpret a zero destination to mean loopback.
1664          * Update the T_CONN_REQ (sin/sin6) since it is used to
1665          * generate the T_CONN_CON.
1666          */
1667         if (IN6_IS_ADDR_UNSPECIFIED(dstaddrp))
1668                 *dstaddrp = ipv6_loopback;
1669 
1670         /* Handle __sin6_src_id if socket not bound to an IP address */
1671         if (srcid != 0 && IN6_IS_ADDR_UNSPECIFIED(&connp->conn_laddr_v6)) {
1672                 if (!ip_srcid_find_id(srcid, &connp->conn_laddr_v6,
1673                     IPCL_ZONEID(connp), B_FALSE, tcps->tcps_netstack)) {
1674                         /* Mismatch - conn_laddr_v6 would be v4-mapped. */
1675                         return (EADDRNOTAVAIL);
1676                 }
1677                 connp->conn_saddr_v6 = connp->conn_laddr_v6;
1678         }
1679 
1680         /*
1681          * Take care of the scope_id now.
1682          */
1683         if (scope_id != 0 && IN6_IS_ADDR_LINKSCOPE(dstaddrp)) {
1684                 connp->conn_ixa->ixa_flags |= IXAF_SCOPEID_SET;
1685                 connp->conn_ixa->ixa_scopeid = scope_id;
1686         } else {
1687                 connp->conn_ixa->ixa_flags &= ~IXAF_SCOPEID_SET;
1688         }
1689 
1690         connp->conn_flowinfo = flowinfo;
1691         connp->conn_faddr_v6 = *dstaddrp;
1692         connp->conn_fport = dstport;
1693 
1694         /*
1695          * At this point the remote destination address and remote port fields
1696          * in the tcp-four-tuple have been filled in the tcp structure. Now we
1697          * have to see which state tcp was in so we can take appropriate action.
1698          */
1699         if (tcp->tcp_state == TCPS_IDLE) {
1700                 /*
1701                  * We support a quick connect capability here, allowing
1702                  * clients to transition directly from IDLE to SYN_SENT
1703                  * tcp_bindi will pick an unused port, insert the connection
1704                  * in the bind hash and transition to BOUND state.
1705                  */
1706                 lport = tcp_update_next_port(tcps->tcps_next_port_to_try,
1707                     tcp, B_TRUE);
1708                 lport = tcp_bindi(tcp, lport, &connp->conn_laddr_v6, 0, B_TRUE,
1709                     B_FALSE, B_FALSE);
1710                 if (lport == 0)
1711                         return (-TNOADDR);
1712         }
1713 
1714         /*
1715          * Lookup the route to determine a source address and the uinfo.
1716          * Setup TCP parameters based on the metrics/DCE.
1717          */
1718         error = tcp_set_destination(tcp);
1719         if (error != 0)
1720                 return (error);
1721 
1722         /*
1723          * Don't let an endpoint connect to itself.
1724          */
1725         if (IN6_ARE_ADDR_EQUAL(&connp->conn_faddr_v6, &connp->conn_laddr_v6) &&
1726             connp->conn_fport == connp->conn_lport)
1727                 return (-TBADADDR);
1728 
1729         tcp->tcp_state = TCPS_SYN_SENT;
1730 
1731         return (ipcl_conn_insert_v6(connp));
1732 }
1733 
1734 /*
1735  * Disconnect
1736  * Note that unlike other functions this returns a positive tli error
1737  * when it fails; it never returns an errno.
1738  */
1739 static int
1740 tcp_disconnect_common(tcp_t *tcp, t_scalar_t seqnum)
1741 {
1742         conn_t          *lconnp;
1743         tcp_stack_t     *tcps = tcp->tcp_tcps;
1744         conn_t          *connp = tcp->tcp_connp;
1745 
1746         /*
1747          * Right now, upper modules pass down a T_DISCON_REQ to TCP,
1748          * when the stream is in BOUND state. Do not send a reset,
1749          * since the destination IP address is not valid, and it can
1750          * be the initialized value of all zeros (broadcast address).
1751          */
1752         if (tcp->tcp_state <= TCPS_BOUND) {
1753                 if (connp->conn_debug) {
1754                         (void) strlog(TCP_MOD_ID, 0, 1, SL_ERROR|SL_TRACE,
1755                             "tcp_disconnect: bad state, %d", tcp->tcp_state);
1756                 }
1757                 return (TOUTSTATE);
1758         } else if (tcp->tcp_state >= TCPS_ESTABLISHED) {
1759                 TCPS_CONN_DEC(tcps);
1760         }
1761 
1762         if (seqnum == -1 || tcp->tcp_conn_req_max == 0) {
1763 
1764                 /*
1765                  * According to TPI, for non-listeners, ignore seqnum
1766                  * and disconnect.
1767                  * Following interpretation of -1 seqnum is historical
1768                  * and implied TPI ? (TPI only states that for T_CONN_IND,
1769                  * a valid seqnum should not be -1).
1770                  *
1771                  *      -1 means disconnect everything
1772                  *      regardless even on a listener.
1773                  */
1774 
1775                 int old_state = tcp->tcp_state;
1776                 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
1777 
1778                 /*
1779                  * The connection can't be on the tcp_time_wait_head list
1780                  * since it is not detached.
1781                  */
1782                 ASSERT(tcp->tcp_time_wait_next == NULL);
1783                 ASSERT(tcp->tcp_time_wait_prev == NULL);
1784                 ASSERT(tcp->tcp_time_wait_expire == 0);
1785                 /*
1786                  * If it used to be a listener, check to make sure no one else
1787                  * has taken the port before switching back to LISTEN state.
1788                  */
1789                 if (connp->conn_ipversion == IPV4_VERSION) {
1790                         lconnp = ipcl_lookup_listener_v4(connp->conn_lport,
1791                             connp->conn_laddr_v4, IPCL_ZONEID(connp), ipst);
1792                 } else {
1793                         uint_t ifindex = 0;
1794 
1795                         if (connp->conn_ixa->ixa_flags & IXAF_SCOPEID_SET)
1796                                 ifindex = connp->conn_ixa->ixa_scopeid;
1797 
1798                         /* Allow conn_bound_if listeners? */
1799                         lconnp = ipcl_lookup_listener_v6(connp->conn_lport,
1800                             &connp->conn_laddr_v6, ifindex, IPCL_ZONEID(connp),
1801                             ipst);
1802                 }
1803                 if (tcp->tcp_conn_req_max && lconnp == NULL) {
1804                         tcp->tcp_state = TCPS_LISTEN;
1805                         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
1806                             connp->conn_ixa, void, NULL, tcp_t *, tcp, void,
1807                             NULL, int32_t, old_state);
1808                 } else if (old_state > TCPS_BOUND) {
1809                         tcp->tcp_conn_req_max = 0;
1810                         tcp->tcp_state = TCPS_BOUND;
1811                         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
1812                             connp->conn_ixa, void, NULL, tcp_t *, tcp, void,
1813                             NULL, int32_t, old_state);
1814 
1815                         /*
1816                          * If this end point is not going to become a listener,
1817                          * decrement the listener connection count if
1818                          * necessary.  Note that we do not do this if it is
1819                          * going to be a listner (the above if case) since
1820                          * then it may remove the counter struct.
1821                          */
1822                         if (tcp->tcp_listen_cnt != NULL)
1823                                 TCP_DECR_LISTEN_CNT(tcp);
1824                 }
1825                 if (lconnp != NULL)
1826                         CONN_DEC_REF(lconnp);
1827                 switch (old_state) {
1828                 case TCPS_SYN_SENT:
1829                 case TCPS_SYN_RCVD:
1830                         TCPS_BUMP_MIB(tcps, tcpAttemptFails);
1831                         break;
1832                 case TCPS_ESTABLISHED:
1833                 case TCPS_CLOSE_WAIT:
1834                         TCPS_BUMP_MIB(tcps, tcpEstabResets);
1835                         break;
1836                 }
1837 
1838                 if (tcp->tcp_fused)
1839                         tcp_unfuse(tcp);
1840 
1841                 mutex_enter(&tcp->tcp_eager_lock);
1842                 if ((tcp->tcp_conn_req_cnt_q0 != 0) ||
1843                     (tcp->tcp_conn_req_cnt_q != 0)) {
1844                         tcp_eager_cleanup(tcp, 0);
1845                 }
1846                 mutex_exit(&tcp->tcp_eager_lock);
1847 
1848                 tcp_xmit_ctl("tcp_disconnect", tcp, tcp->tcp_snxt,
1849                     tcp->tcp_rnxt, TH_RST | TH_ACK);
1850 
1851                 tcp_reinit(tcp);
1852 
1853                 return (0);
1854         } else if (!tcp_eager_blowoff(tcp, seqnum)) {
1855                 return (TBADSEQ);
1856         }
1857         return (0);
1858 }
1859 
1860 /*
1861  * Our client hereby directs us to reject the connection request
1862  * that tcp_input_listener() marked with 'seqnum'.  Rejection consists
1863  * of sending the appropriate RST, not an ICMP error.
1864  */
1865 void
1866 tcp_disconnect(tcp_t *tcp, mblk_t *mp)
1867 {
1868         t_scalar_t seqnum;
1869         int     error;
1870         conn_t  *connp = tcp->tcp_connp;
1871 
1872         ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)INT_MAX);
1873         if ((mp->b_wptr - mp->b_rptr) < sizeof (struct T_discon_req)) {
1874                 tcp_err_ack(tcp, mp, TPROTO, 0);
1875                 return;
1876         }
1877         seqnum = ((struct T_discon_req *)mp->b_rptr)->SEQ_number;
1878         error = tcp_disconnect_common(tcp, seqnum);
1879         if (error != 0)
1880                 tcp_err_ack(tcp, mp, error, 0);
1881         else {
1882                 if (tcp->tcp_state >= TCPS_ESTABLISHED) {
1883                         /* Send M_FLUSH according to TPI */
1884                         (void) putnextctl1(connp->conn_rq, M_FLUSH, FLUSHRW);
1885                 }
1886                 mp = mi_tpi_ok_ack_alloc(mp);
1887                 if (mp != NULL)
1888                         putnext(connp->conn_rq, mp);
1889         }
1890 }
1891 
1892 /*
1893  * Handle reinitialization of a tcp structure.
1894  * Maintain "binding state" resetting the state to BOUND, LISTEN, or IDLE.
1895  */
1896 static void
1897 tcp_reinit(tcp_t *tcp)
1898 {
1899         mblk_t          *mp;
1900         tcp_stack_t     *tcps = tcp->tcp_tcps;
1901         conn_t          *connp  = tcp->tcp_connp;
1902         int32_t         oldstate;
1903 
1904         /* tcp_reinit should never be called for detached tcp_t's */
1905         ASSERT(tcp->tcp_listener == NULL);
1906         ASSERT((connp->conn_family == AF_INET &&
1907             connp->conn_ipversion == IPV4_VERSION) ||
1908             (connp->conn_family == AF_INET6 &&
1909             (connp->conn_ipversion == IPV4_VERSION ||
1910             connp->conn_ipversion == IPV6_VERSION)));
1911 
1912         /* Cancel outstanding timers */
1913         tcp_timers_stop(tcp);
1914 
1915         /*
1916          * Reset everything in the state vector, after updating global
1917          * MIB data from instance counters.
1918          */
1919         TCPS_UPDATE_MIB(tcps, tcpHCInSegs, tcp->tcp_ibsegs);
1920         tcp->tcp_ibsegs = 0;
1921         TCPS_UPDATE_MIB(tcps, tcpHCOutSegs, tcp->tcp_obsegs);
1922         tcp->tcp_obsegs = 0;
1923 
1924         tcp_close_mpp(&tcp->tcp_xmit_head);
1925         if (tcp->tcp_snd_zcopy_aware)
1926                 tcp_zcopy_notify(tcp);
1927         tcp->tcp_xmit_last = tcp->tcp_xmit_tail = NULL;
1928         tcp->tcp_unsent = tcp->tcp_xmit_tail_unsent = 0;
1929         mutex_enter(&tcp->tcp_non_sq_lock);
1930         if (tcp->tcp_flow_stopped &&
1931             TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat) {
1932                 tcp_clrqfull(tcp);
1933         }
1934         mutex_exit(&tcp->tcp_non_sq_lock);
1935         tcp_close_mpp(&tcp->tcp_reass_head);
1936         tcp->tcp_reass_tail = NULL;
1937         if (tcp->tcp_rcv_list != NULL) {
1938                 /* Free b_next chain */
1939                 tcp_close_mpp(&tcp->tcp_rcv_list);
1940                 tcp->tcp_rcv_last_head = NULL;
1941                 tcp->tcp_rcv_last_tail = NULL;
1942                 tcp->tcp_rcv_cnt = 0;
1943         }
1944         tcp->tcp_rcv_last_tail = NULL;
1945 
1946         if ((mp = tcp->tcp_urp_mp) != NULL) {
1947                 freemsg(mp);
1948                 tcp->tcp_urp_mp = NULL;
1949         }
1950         if ((mp = tcp->tcp_urp_mark_mp) != NULL) {
1951                 freemsg(mp);
1952                 tcp->tcp_urp_mark_mp = NULL;
1953         }
1954         if (tcp->tcp_fused_sigurg_mp != NULL) {
1955                 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
1956                 freeb(tcp->tcp_fused_sigurg_mp);
1957                 tcp->tcp_fused_sigurg_mp = NULL;
1958         }
1959         if (tcp->tcp_ordrel_mp != NULL) {
1960                 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
1961                 freeb(tcp->tcp_ordrel_mp);
1962                 tcp->tcp_ordrel_mp = NULL;
1963         }
1964 
1965         /*
1966          * Following is a union with two members which are
1967          * identical types and size so the following cleanup
1968          * is enough.
1969          */
1970         tcp_close_mpp(&tcp->tcp_conn.tcp_eager_conn_ind);
1971 
1972         CL_INET_DISCONNECT(connp);
1973 
1974         /*
1975          * The connection can't be on the tcp_time_wait_head list
1976          * since it is not detached.
1977          */
1978         ASSERT(tcp->tcp_time_wait_next == NULL);
1979         ASSERT(tcp->tcp_time_wait_prev == NULL);
1980         ASSERT(tcp->tcp_time_wait_expire == 0);
1981 
1982         /*
1983          * Reset/preserve other values
1984          */
1985         tcp_reinit_values(tcp);
1986         ipcl_hash_remove(connp);
1987         /* Note that ixa_cred gets cleared in ixa_cleanup */
1988         ixa_cleanup(connp->conn_ixa);
1989         tcp_ipsec_cleanup(tcp);
1990 
1991         connp->conn_laddr_v6 = connp->conn_bound_addr_v6;
1992         connp->conn_saddr_v6 = connp->conn_bound_addr_v6;
1993         oldstate = tcp->tcp_state;
1994 
1995         if (tcp->tcp_conn_req_max != 0) {
1996                 /*
1997                  * This is the case when a TLI program uses the same
1998                  * transport end point to accept a connection.  This
1999                  * makes the TCP both a listener and acceptor.  When
2000                  * this connection is closed, we need to set the state
2001                  * back to TCPS_LISTEN.  Make sure that the eager list
2002                  * is reinitialized.
2003                  *
2004                  * Note that this stream is still bound to the four
2005                  * tuples of the previous connection in IP.  If a new
2006                  * SYN with different foreign address comes in, IP will
2007                  * not find it and will send it to the global queue.  In
2008                  * the global queue, TCP will do a tcp_lookup_listener()
2009                  * to find this stream.  This works because this stream
2010                  * is only removed from connected hash.
2011                  *
2012                  */
2013                 tcp->tcp_state = TCPS_LISTEN;
2014                 tcp->tcp_eager_next_q0 = tcp->tcp_eager_prev_q0 = tcp;
2015                 tcp->tcp_eager_next_drop_q0 = tcp;
2016                 tcp->tcp_eager_prev_drop_q0 = tcp;
2017                 /*
2018                  * Initially set conn_recv to tcp_input_listener_unbound to try
2019                  * to pick a good squeue for the listener when the first SYN
2020                  * arrives. tcp_input_listener_unbound sets it to
2021                  * tcp_input_listener on that first SYN.
2022                  */
2023                 connp->conn_recv = tcp_input_listener_unbound;
2024 
2025                 connp->conn_proto = IPPROTO_TCP;
2026                 connp->conn_faddr_v6 = ipv6_all_zeros;
2027                 connp->conn_fport = 0;
2028 
2029                 (void) ipcl_bind_insert(connp);
2030         } else {
2031                 tcp->tcp_state = TCPS_BOUND;
2032         }
2033 
2034         /*
2035          * Initialize to default values
2036          */
2037         tcp_init_values(tcp, NULL);
2038 
2039         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
2040             connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
2041             int32_t, oldstate);
2042 
2043         ASSERT(tcp->tcp_ptpbhn != NULL);
2044         tcp->tcp_rwnd = connp->conn_rcvbuf;
2045         tcp->tcp_mss = connp->conn_ipversion != IPV4_VERSION ?
2046             tcps->tcps_mss_def_ipv6 : tcps->tcps_mss_def_ipv4;
2047 }
2048 
2049 /*
2050  * Force values to zero that need be zero.
2051  * Do not touch values asociated with the BOUND or LISTEN state
2052  * since the connection will end up in that state after the reinit.
2053  * NOTE: tcp_reinit_values MUST have a line for each field in the tcp_t
2054  * structure!
2055  */
2056 static void
2057 tcp_reinit_values(tcp_t *tcp)
2058 {
2059         tcp_stack_t     *tcps = tcp->tcp_tcps;
2060         conn_t          *connp = tcp->tcp_connp;
2061 
2062 #ifndef lint
2063 #define DONTCARE(x)
2064 #define PRESERVE(x)
2065 #else
2066 #define DONTCARE(x)     ((x) = (x))
2067 #define PRESERVE(x)     ((x) = (x))
2068 #endif  /* lint */
2069 
2070         PRESERVE(tcp->tcp_bind_hash_port);
2071         PRESERVE(tcp->tcp_bind_hash);
2072         PRESERVE(tcp->tcp_ptpbhn);
2073         PRESERVE(tcp->tcp_acceptor_hash);
2074         PRESERVE(tcp->tcp_ptpahn);
2075 
2076         /* Should be ASSERT NULL on these with new code! */
2077         ASSERT(tcp->tcp_time_wait_next == NULL);
2078         ASSERT(tcp->tcp_time_wait_prev == NULL);
2079         ASSERT(tcp->tcp_time_wait_expire == 0);
2080         PRESERVE(tcp->tcp_state);
2081         PRESERVE(connp->conn_rq);
2082         PRESERVE(connp->conn_wq);
2083 
2084         ASSERT(tcp->tcp_xmit_head == NULL);
2085         ASSERT(tcp->tcp_xmit_last == NULL);
2086         ASSERT(tcp->tcp_unsent == 0);
2087         ASSERT(tcp->tcp_xmit_tail == NULL);
2088         ASSERT(tcp->tcp_xmit_tail_unsent == 0);
2089 
2090         tcp->tcp_snxt = 0;                   /* Displayed in mib */
2091         tcp->tcp_suna = 0;                   /* Displayed in mib */
2092         tcp->tcp_swnd = 0;
2093         DONTCARE(tcp->tcp_cwnd);     /* Init in tcp_process_options */
2094 
2095         ASSERT(tcp->tcp_ibsegs == 0);
2096         ASSERT(tcp->tcp_obsegs == 0);
2097 
2098         if (connp->conn_ht_iphc != NULL) {
2099                 kmem_free(connp->conn_ht_iphc, connp->conn_ht_iphc_allocated);
2100                 connp->conn_ht_iphc = NULL;
2101                 connp->conn_ht_iphc_allocated = 0;
2102                 connp->conn_ht_iphc_len = 0;
2103                 connp->conn_ht_ulp = NULL;
2104                 connp->conn_ht_ulp_len = 0;
2105                 tcp->tcp_ipha = NULL;
2106                 tcp->tcp_ip6h = NULL;
2107                 tcp->tcp_tcpha = NULL;
2108         }
2109 
2110         /* We clear any IP_OPTIONS and extension headers */
2111         ip_pkt_free(&connp->conn_xmit_ipp);
2112 
2113         DONTCARE(tcp->tcp_naglim);           /* Init in tcp_init_values */
2114         DONTCARE(tcp->tcp_ipha);
2115         DONTCARE(tcp->tcp_ip6h);
2116         DONTCARE(tcp->tcp_tcpha);
2117         tcp->tcp_valid_bits = 0;
2118 
2119         DONTCARE(tcp->tcp_timer_backoff);    /* Init in tcp_init_values */
2120         DONTCARE(tcp->tcp_last_recv_time);   /* Init in tcp_init_values */
2121         tcp->tcp_last_rcv_lbolt = 0;
2122 
2123         tcp->tcp_init_cwnd = 0;
2124 
2125         tcp->tcp_urp_last_valid = 0;
2126         tcp->tcp_hard_binding = 0;
2127 
2128         tcp->tcp_fin_acked = 0;
2129         tcp->tcp_fin_rcvd = 0;
2130         tcp->tcp_fin_sent = 0;
2131         tcp->tcp_ordrel_done = 0;
2132 
2133         tcp->tcp_detached = 0;
2134 
2135         tcp->tcp_snd_ws_ok = B_FALSE;
2136         tcp->tcp_snd_ts_ok = B_FALSE;
2137         tcp->tcp_zero_win_probe = 0;
2138 
2139         tcp->tcp_loopback = 0;
2140         tcp->tcp_localnet = 0;
2141         tcp->tcp_syn_defense = 0;
2142         tcp->tcp_set_timer = 0;
2143 
2144         tcp->tcp_active_open = 0;
2145         tcp->tcp_rexmit = B_FALSE;
2146         tcp->tcp_xmit_zc_clean = B_FALSE;
2147 
2148         tcp->tcp_snd_sack_ok = B_FALSE;
2149         tcp->tcp_hwcksum = B_FALSE;
2150 
2151         DONTCARE(tcp->tcp_maxpsz_multiplier);        /* Init in tcp_init_values */
2152 
2153         tcp->tcp_conn_def_q0 = 0;
2154         tcp->tcp_ip_forward_progress = B_FALSE;
2155         tcp->tcp_ecn_ok = B_FALSE;
2156 
2157         tcp->tcp_cwr = B_FALSE;
2158         tcp->tcp_ecn_echo_on = B_FALSE;
2159         tcp->tcp_is_wnd_shrnk = B_FALSE;
2160 
2161         TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list, tcp);
2162         bzero(&tcp->tcp_sack_info, sizeof (tcp_sack_info_t));
2163 
2164         tcp->tcp_rcv_ws = 0;
2165         tcp->tcp_snd_ws = 0;
2166         tcp->tcp_ts_recent = 0;
2167         tcp->tcp_rnxt = 0;                   /* Displayed in mib */
2168         DONTCARE(tcp->tcp_rwnd);             /* Set in tcp_reinit() */
2169         tcp->tcp_initial_pmtu = 0;
2170 
2171         ASSERT(tcp->tcp_reass_head == NULL);
2172         ASSERT(tcp->tcp_reass_tail == NULL);
2173 
2174         tcp->tcp_cwnd_cnt = 0;
2175 
2176         ASSERT(tcp->tcp_rcv_list == NULL);
2177         ASSERT(tcp->tcp_rcv_last_head == NULL);
2178         ASSERT(tcp->tcp_rcv_last_tail == NULL);
2179         ASSERT(tcp->tcp_rcv_cnt == 0);
2180 
2181         DONTCARE(tcp->tcp_cwnd_ssthresh); /* Init in tcp_set_destination */
2182         DONTCARE(tcp->tcp_cwnd_max);         /* Init in tcp_init_values */
2183         tcp->tcp_csuna = 0;
2184 
2185         tcp->tcp_rto = 0;                    /* Displayed in MIB */
2186         DONTCARE(tcp->tcp_rtt_sa);           /* Init in tcp_init_values */
2187         DONTCARE(tcp->tcp_rtt_sd);           /* Init in tcp_init_values */
2188         tcp->tcp_rtt_update = 0;
2189 
2190         DONTCARE(tcp->tcp_swl1); /* Init in case TCPS_LISTEN/TCPS_SYN_SENT */
2191         DONTCARE(tcp->tcp_swl2); /* Init in case TCPS_LISTEN/TCPS_SYN_SENT */
2192 
2193         tcp->tcp_rack = 0;                   /* Displayed in mib */
2194         tcp->tcp_rack_cnt = 0;
2195         tcp->tcp_rack_cur_max = 0;
2196         tcp->tcp_rack_abs_max = 0;
2197 
2198         tcp->tcp_max_swnd = 0;
2199 
2200         ASSERT(tcp->tcp_listener == NULL);
2201 
2202         DONTCARE(tcp->tcp_irs);                      /* tcp_valid_bits cleared */
2203         DONTCARE(tcp->tcp_iss);                      /* tcp_valid_bits cleared */
2204         DONTCARE(tcp->tcp_fss);                      /* tcp_valid_bits cleared */
2205         DONTCARE(tcp->tcp_urg);                      /* tcp_valid_bits cleared */
2206 
2207         ASSERT(tcp->tcp_conn_req_cnt_q == 0);
2208         ASSERT(tcp->tcp_conn_req_cnt_q0 == 0);
2209         PRESERVE(tcp->tcp_conn_req_max);
2210         PRESERVE(tcp->tcp_conn_req_seqnum);
2211 
2212         DONTCARE(tcp->tcp_first_timer_threshold); /* Init in tcp_init_values */
2213         DONTCARE(tcp->tcp_second_timer_threshold); /* Init in tcp_init_values */
2214         DONTCARE(tcp->tcp_first_ctimer_threshold); /* Init in tcp_init_values */
2215         DONTCARE(tcp->tcp_second_ctimer_threshold); /* in tcp_init_values */
2216 
2217         DONTCARE(tcp->tcp_urp_last); /* tcp_urp_last_valid is cleared */
2218         ASSERT(tcp->tcp_urp_mp == NULL);
2219         ASSERT(tcp->tcp_urp_mark_mp == NULL);
2220         ASSERT(tcp->tcp_fused_sigurg_mp == NULL);
2221 
2222         ASSERT(tcp->tcp_eager_next_q == NULL);
2223         ASSERT(tcp->tcp_eager_last_q == NULL);
2224         ASSERT((tcp->tcp_eager_next_q0 == NULL &&
2225             tcp->tcp_eager_prev_q0 == NULL) ||
2226             tcp->tcp_eager_next_q0 == tcp->tcp_eager_prev_q0);
2227         ASSERT(tcp->tcp_conn.tcp_eager_conn_ind == NULL);
2228 
2229         ASSERT((tcp->tcp_eager_next_drop_q0 == NULL &&
2230             tcp->tcp_eager_prev_drop_q0 == NULL) ||
2231             tcp->tcp_eager_next_drop_q0 == tcp->tcp_eager_prev_drop_q0);
2232 
2233         DONTCARE(tcp->tcp_ka_rinterval);     /* Init in tcp_init_values */
2234         DONTCARE(tcp->tcp_ka_abort_thres);   /* Init in tcp_init_values */
2235         DONTCARE(tcp->tcp_ka_cnt);           /* Init in tcp_init_values */
2236 
2237         tcp->tcp_client_errno = 0;
2238 
2239         DONTCARE(connp->conn_sum);           /* Init in tcp_init_values */
2240 
2241         connp->conn_faddr_v6 = ipv6_all_zeros;       /* Displayed in MIB */
2242 
2243         PRESERVE(connp->conn_bound_addr_v6);
2244         tcp->tcp_last_sent_len = 0;
2245         tcp->tcp_dupack_cnt = 0;
2246 
2247         connp->conn_fport = 0;                       /* Displayed in MIB */
2248         PRESERVE(connp->conn_lport);
2249 
2250         PRESERVE(tcp->tcp_acceptor_lockp);
2251 
2252         ASSERT(tcp->tcp_ordrel_mp == NULL);
2253         PRESERVE(tcp->tcp_acceptor_id);
2254         DONTCARE(tcp->tcp_ipsec_overhead);
2255 
2256         PRESERVE(connp->conn_family);
2257         /* Remove any remnants of mapped address binding */
2258         if (connp->conn_family == AF_INET6) {
2259                 connp->conn_ipversion = IPV6_VERSION;
2260                 tcp->tcp_mss = tcps->tcps_mss_def_ipv6;
2261         } else {
2262                 connp->conn_ipversion = IPV4_VERSION;
2263                 tcp->tcp_mss = tcps->tcps_mss_def_ipv4;
2264         }
2265 
2266         connp->conn_bound_if = 0;
2267         connp->conn_recv_ancillary.crb_all = 0;
2268         tcp->tcp_recvifindex = 0;
2269         tcp->tcp_recvhops = 0;
2270         tcp->tcp_closed = 0;
2271         if (tcp->tcp_hopopts != NULL) {
2272                 mi_free(tcp->tcp_hopopts);
2273                 tcp->tcp_hopopts = NULL;
2274                 tcp->tcp_hopoptslen = 0;
2275         }
2276         ASSERT(tcp->tcp_hopoptslen == 0);
2277         if (tcp->tcp_dstopts != NULL) {
2278                 mi_free(tcp->tcp_dstopts);
2279                 tcp->tcp_dstopts = NULL;
2280                 tcp->tcp_dstoptslen = 0;
2281         }
2282         ASSERT(tcp->tcp_dstoptslen == 0);
2283         if (tcp->tcp_rthdrdstopts != NULL) {
2284                 mi_free(tcp->tcp_rthdrdstopts);
2285                 tcp->tcp_rthdrdstopts = NULL;
2286                 tcp->tcp_rthdrdstoptslen = 0;
2287         }
2288         ASSERT(tcp->tcp_rthdrdstoptslen == 0);
2289         if (tcp->tcp_rthdr != NULL) {
2290                 mi_free(tcp->tcp_rthdr);
2291                 tcp->tcp_rthdr = NULL;
2292                 tcp->tcp_rthdrlen = 0;
2293         }
2294         ASSERT(tcp->tcp_rthdrlen == 0);
2295 
2296         /* Reset fusion-related fields */
2297         tcp->tcp_fused = B_FALSE;
2298         tcp->tcp_unfusable = B_FALSE;
2299         tcp->tcp_fused_sigurg = B_FALSE;
2300         tcp->tcp_loopback_peer = NULL;
2301 
2302         tcp->tcp_lso = B_FALSE;
2303 
2304         tcp->tcp_in_ack_unsent = 0;
2305         tcp->tcp_cork = B_FALSE;
2306         tcp->tcp_tconnind_started = B_FALSE;
2307 
2308         PRESERVE(tcp->tcp_squeue_bytes);
2309 
2310         tcp->tcp_closemp_used = B_FALSE;
2311 
2312         PRESERVE(tcp->tcp_rsrv_mp);
2313         PRESERVE(tcp->tcp_rsrv_mp_lock);
2314 
2315 #ifdef DEBUG
2316         DONTCARE(tcp->tcmp_stk[0]);
2317 #endif
2318 
2319         PRESERVE(tcp->tcp_connid);
2320 
2321         ASSERT(tcp->tcp_listen_cnt == NULL);
2322         ASSERT(tcp->tcp_reass_tid == 0);
2323 
2324 #undef  DONTCARE
2325 #undef  PRESERVE
2326 }
2327 
2328 /*
2329  * Initialize the various fields in tcp_t.  If parent (the listener) is non
2330  * NULL, certain values will be inheritted from it.
2331  */
2332 void
2333 tcp_init_values(tcp_t *tcp, tcp_t *parent)
2334 {
2335         tcp_stack_t     *tcps = tcp->tcp_tcps;
2336         conn_t          *connp = tcp->tcp_connp;
2337         clock_t         rto;
2338 
2339         ASSERT((connp->conn_family == AF_INET &&
2340             connp->conn_ipversion == IPV4_VERSION) ||
2341             (connp->conn_family == AF_INET6 &&
2342             (connp->conn_ipversion == IPV4_VERSION ||
2343             connp->conn_ipversion == IPV6_VERSION)));
2344 
2345         if (parent == NULL) {
2346                 tcp->tcp_naglim = tcps->tcps_naglim_def;
2347 
2348                 tcp->tcp_rto_initial = tcps->tcps_rexmit_interval_initial;
2349                 tcp->tcp_rto_min = tcps->tcps_rexmit_interval_min;
2350                 tcp->tcp_rto_max = tcps->tcps_rexmit_interval_max;
2351 
2352                 tcp->tcp_first_ctimer_threshold =
2353                     tcps->tcps_ip_notify_cinterval;
2354                 tcp->tcp_second_ctimer_threshold =
2355                     tcps->tcps_ip_abort_cinterval;
2356                 tcp->tcp_first_timer_threshold = tcps->tcps_ip_notify_interval;
2357                 tcp->tcp_second_timer_threshold = tcps->tcps_ip_abort_interval;
2358 
2359                 tcp->tcp_fin_wait_2_flush_interval =
2360                     tcps->tcps_fin_wait_2_flush_interval;
2361 
2362                 tcp->tcp_ka_interval = tcps->tcps_keepalive_interval;
2363                 tcp->tcp_ka_abort_thres = tcps->tcps_keepalive_abort_interval;
2364                 tcp->tcp_ka_cnt = 0;
2365                 tcp->tcp_ka_rinterval = 0;
2366 
2367                 /*
2368                  * Default value of tcp_init_cwnd is 0, so no need to set here
2369                  * if parent is NULL.  But we need to inherit it from parent.
2370                  */
2371         } else {
2372                 /* Inherit various TCP parameters from the parent. */
2373                 tcp->tcp_naglim = parent->tcp_naglim;
2374 
2375                 tcp->tcp_rto_initial = parent->tcp_rto_initial;
2376                 tcp->tcp_rto_min = parent->tcp_rto_min;
2377                 tcp->tcp_rto_max = parent->tcp_rto_max;
2378 
2379                 tcp->tcp_first_ctimer_threshold =
2380                     parent->tcp_first_ctimer_threshold;
2381                 tcp->tcp_second_ctimer_threshold =
2382                     parent->tcp_second_ctimer_threshold;
2383                 tcp->tcp_first_timer_threshold =
2384                     parent->tcp_first_timer_threshold;
2385                 tcp->tcp_second_timer_threshold =
2386                     parent->tcp_second_timer_threshold;
2387 
2388                 tcp->tcp_fin_wait_2_flush_interval =
2389                     parent->tcp_fin_wait_2_flush_interval;
2390 
2391                 tcp->tcp_ka_interval = parent->tcp_ka_interval;
2392                 tcp->tcp_ka_abort_thres = parent->tcp_ka_abort_thres;
2393                 tcp->tcp_ka_cnt = parent->tcp_ka_cnt;
2394                 tcp->tcp_ka_rinterval = parent->tcp_ka_rinterval;
2395 
2396                 tcp->tcp_init_cwnd = parent->tcp_init_cwnd;
2397         }
2398 
2399         /*
2400          * Initialize tcp_rtt_sa and tcp_rtt_sd so that the calculated RTO
2401          * will be close to tcp_rexmit_interval_initial.  By doing this, we
2402          * allow the algorithm to adjust slowly to large fluctuations of RTT
2403          * during first few transmissions of a connection as seen in slow
2404          * links.
2405          */
2406         tcp->tcp_rtt_sa = tcp->tcp_rto_initial << 2;
2407         tcp->tcp_rtt_sd = tcp->tcp_rto_initial >> 1;
2408         rto = (tcp->tcp_rtt_sa >> 3) + tcp->tcp_rtt_sd +
2409             tcps->tcps_rexmit_interval_extra + (tcp->tcp_rtt_sa >> 5) +
2410             tcps->tcps_conn_grace_period;
2411         TCP_SET_RTO(tcp, rto);
2412 
2413         tcp->tcp_timer_backoff = 0;
2414         tcp->tcp_ms_we_have_waited = 0;
2415         tcp->tcp_last_recv_time = ddi_get_lbolt();
2416         tcp->tcp_cwnd_max = tcps->tcps_cwnd_max_;
2417         tcp->tcp_cwnd_ssthresh = TCP_MAX_LARGEWIN;
2418 
2419         tcp->tcp_maxpsz_multiplier = tcps->tcps_maxpsz_multiplier;
2420 
2421         /* NOTE:  ISS is now set in tcp_set_destination(). */
2422 
2423         /* Reset fusion-related fields */
2424         tcp->tcp_fused = B_FALSE;
2425         tcp->tcp_unfusable = B_FALSE;
2426         tcp->tcp_fused_sigurg = B_FALSE;
2427         tcp->tcp_loopback_peer = NULL;
2428 
2429         /* We rebuild the header template on the next connect/conn_request */
2430 
2431         connp->conn_mlp_type = mlptSingle;
2432 
2433         /*
2434          * Init the window scale to the max so tcp_rwnd_set() won't pare
2435          * down tcp_rwnd. tcp_set_destination() will set the right value later.
2436          */
2437         tcp->tcp_rcv_ws = TCP_MAX_WINSHIFT;
2438         tcp->tcp_rwnd = connp->conn_rcvbuf;
2439 
2440         tcp->tcp_cork = B_FALSE;
2441         /*
2442          * Init the tcp_debug option if it wasn't already set.  This value
2443          * determines whether TCP
2444          * calls strlog() to print out debug messages.  Doing this
2445          * initialization here means that this value is not inherited thru
2446          * tcp_reinit().
2447          */
2448         if (!connp->conn_debug)
2449                 connp->conn_debug = tcps->tcps_dbg;
2450 }
2451 
2452 /*
2453  * Update the TCP connection according to change of PMTU.
2454  *
2455  * Path MTU might have changed by either increase or decrease, so need to
2456  * adjust the MSS based on the value of ixa_pmtu. No need to handle tiny
2457  * or negative MSS, since tcp_mss_set() will do it.
2458  */
2459 void
2460 tcp_update_pmtu(tcp_t *tcp, boolean_t decrease_only)
2461 {
2462         uint32_t        pmtu;
2463         int32_t         mss;
2464         conn_t          *connp = tcp->tcp_connp;
2465         ip_xmit_attr_t  *ixa = connp->conn_ixa;
2466         iaflags_t       ixaflags;
2467 
2468         if (tcp->tcp_tcps->tcps_ignore_path_mtu)
2469                 return;
2470 
2471         if (tcp->tcp_state < TCPS_ESTABLISHED)
2472                 return;
2473 
2474         /*
2475          * Always call ip_get_pmtu() to make sure that IP has updated
2476          * ixa_flags properly.
2477          */
2478         pmtu = ip_get_pmtu(ixa);
2479         ixaflags = ixa->ixa_flags;
2480 
2481         /*
2482          * Calculate the MSS by decreasing the PMTU by conn_ht_iphc_len and
2483          * IPsec overhead if applied. Make sure to use the most recent
2484          * IPsec information.
2485          */
2486         mss = pmtu - connp->conn_ht_iphc_len - conn_ipsec_length(connp);
2487 
2488         /*
2489          * Nothing to change, so just return.
2490          */
2491         if (mss == tcp->tcp_mss)
2492                 return;
2493 
2494         /*
2495          * Currently, for ICMP errors, only PMTU decrease is handled.
2496          */
2497         if (mss > tcp->tcp_mss && decrease_only)
2498                 return;
2499 
2500         DTRACE_PROBE2(tcp_update_pmtu, int32_t, tcp->tcp_mss, uint32_t, mss);
2501 
2502         /*
2503          * Update ixa_fragsize and ixa_pmtu.
2504          */
2505         ixa->ixa_fragsize = ixa->ixa_pmtu = pmtu;
2506 
2507         /*
2508          * Adjust MSS and all relevant variables.
2509          */
2510         tcp_mss_set(tcp, mss);
2511 
2512         /*
2513          * If the PMTU is below the min size maintained by IP, then ip_get_pmtu
2514          * has set IXAF_PMTU_TOO_SMALL and cleared IXAF_PMTU_IPV4_DF. Since TCP
2515          * has a (potentially different) min size we do the same. Make sure to
2516          * clear IXAF_DONTFRAG, which is used by IP to decide whether to
2517          * fragment the packet.
2518          *
2519          * LSO over IPv6 can not be fragmented. So need to disable LSO
2520          * when IPv6 fragmentation is needed.
2521          */
2522         if (mss < tcp->tcp_tcps->tcps_mss_min)
2523                 ixaflags |= IXAF_PMTU_TOO_SMALL;
2524 
2525         if (ixaflags & IXAF_PMTU_TOO_SMALL)
2526                 ixaflags &= ~(IXAF_DONTFRAG | IXAF_PMTU_IPV4_DF);
2527 
2528         if ((connp->conn_ipversion == IPV4_VERSION) &&
2529             !(ixaflags & IXAF_PMTU_IPV4_DF)) {
2530                 tcp->tcp_ipha->ipha_fragment_offset_and_flags = 0;
2531         }
2532         ixa->ixa_flags = ixaflags;
2533 }
2534 
2535 int
2536 tcp_maxpsz_set(tcp_t *tcp, boolean_t set_maxblk)
2537 {
2538         conn_t  *connp = tcp->tcp_connp;
2539         queue_t *q = connp->conn_rq;
2540         int32_t mss = tcp->tcp_mss;
2541         int     maxpsz;
2542 
2543         if (TCP_IS_DETACHED(tcp))
2544                 return (mss);
2545         if (tcp->tcp_fused) {
2546                 maxpsz = tcp_fuse_maxpsz(tcp);
2547                 mss = INFPSZ;
2548         } else if (tcp->tcp_maxpsz_multiplier == 0) {
2549                 /*
2550                  * Set the sd_qn_maxpsz according to the socket send buffer
2551                  * size, and sd_maxblk to INFPSZ (-1).  This will essentially
2552                  * instruct the stream head to copyin user data into contiguous
2553                  * kernel-allocated buffers without breaking it up into smaller
2554                  * chunks.  We round up the buffer size to the nearest SMSS.
2555                  */
2556                 maxpsz = MSS_ROUNDUP(connp->conn_sndbuf, mss);
2557                 mss = INFPSZ;
2558         } else {
2559                 /*
2560                  * Set sd_qn_maxpsz to approx half the (receivers) buffer
2561                  * (and a multiple of the mss).  This instructs the stream
2562                  * head to break down larger than SMSS writes into SMSS-
2563                  * size mblks, up to tcp_maxpsz_multiplier mblks at a time.
2564                  */
2565                 maxpsz = tcp->tcp_maxpsz_multiplier * mss;
2566                 if (maxpsz > connp->conn_sndbuf / 2) {
2567                         maxpsz = connp->conn_sndbuf / 2;
2568                         /* Round up to nearest mss */
2569                         maxpsz = MSS_ROUNDUP(maxpsz, mss);
2570                 }
2571         }
2572 
2573         (void) proto_set_maxpsz(q, connp, maxpsz);
2574         if (!(IPCL_IS_NONSTR(connp)))
2575                 connp->conn_wq->q_maxpsz = maxpsz;
2576         if (set_maxblk)
2577                 (void) proto_set_tx_maxblk(q, connp, mss);
2578         return (mss);
2579 }
2580 
2581 /* For /dev/tcp aka AF_INET open */
2582 static int
2583 tcp_openv4(queue_t *q, dev_t *devp, int flag, int sflag, cred_t *credp)
2584 {
2585         return (tcp_open(q, devp, flag, sflag, credp, B_FALSE));
2586 }
2587 
2588 /* For /dev/tcp6 aka AF_INET6 open */
2589 static int
2590 tcp_openv6(queue_t *q, dev_t *devp, int flag, int sflag, cred_t *credp)
2591 {
2592         return (tcp_open(q, devp, flag, sflag, credp, B_TRUE));
2593 }
2594 
2595 conn_t *
2596 tcp_create_common(cred_t *credp, boolean_t isv6, boolean_t issocket,
2597     int *errorp)
2598 {
2599         tcp_t           *tcp = NULL;
2600         conn_t          *connp;
2601         zoneid_t        zoneid;
2602         tcp_stack_t     *tcps;
2603         squeue_t        *sqp;
2604 
2605         ASSERT(errorp != NULL);
2606         /*
2607          * Find the proper zoneid and netstack.
2608          */
2609         /*
2610          * Special case for install: miniroot needs to be able to
2611          * access files via NFS as though it were always in the
2612          * global zone.
2613          */
2614         if (credp == kcred && nfs_global_client_only != 0) {
2615                 zoneid = GLOBAL_ZONEID;
2616                 tcps = netstack_find_by_stackid(GLOBAL_NETSTACKID)->
2617                     netstack_tcp;
2618                 ASSERT(tcps != NULL);
2619         } else {
2620                 netstack_t *ns;
2621                 int err;
2622 
2623                 if ((err = secpolicy_basic_net_access(credp)) != 0) {
2624                         *errorp = err;
2625                         return (NULL);
2626                 }
2627 
2628                 ns = netstack_find_by_cred(credp);
2629                 ASSERT(ns != NULL);
2630                 tcps = ns->netstack_tcp;
2631                 ASSERT(tcps != NULL);
2632 
2633                 /*
2634                  * For exclusive stacks we set the zoneid to zero
2635                  * to make TCP operate as if in the global zone.
2636                  */
2637                 if (tcps->tcps_netstack->netstack_stackid !=
2638                     GLOBAL_NETSTACKID)
2639                         zoneid = GLOBAL_ZONEID;
2640                 else
2641                         zoneid = crgetzoneid(credp);
2642         }
2643 
2644         sqp = IP_SQUEUE_GET((uint_t)gethrtime());
2645         connp = (conn_t *)tcp_get_conn(sqp, tcps);
2646         /*
2647          * Both tcp_get_conn and netstack_find_by_cred incremented refcnt,
2648          * so we drop it by one.
2649          */
2650         netstack_rele(tcps->tcps_netstack);
2651         if (connp == NULL) {
2652                 *errorp = ENOSR;
2653                 return (NULL);
2654         }
2655         ASSERT(connp->conn_ixa->ixa_protocol == connp->conn_proto);
2656 
2657         connp->conn_sqp = sqp;
2658         connp->conn_initial_sqp = connp->conn_sqp;
2659         connp->conn_ixa->ixa_sqp = connp->conn_sqp;
2660         tcp = connp->conn_tcp;
2661 
2662         /*
2663          * Besides asking IP to set the checksum for us, have conn_ip_output
2664          * to do the following checks when necessary:
2665          *
2666          * IXAF_VERIFY_SOURCE: drop packets when our outer source goes invalid
2667          * IXAF_VERIFY_PMTU: verify PMTU changes
2668          * IXAF_VERIFY_LSO: verify LSO capability changes
2669          */
2670         connp->conn_ixa->ixa_flags |= IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE |
2671             IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO;
2672 
2673         if (!tcps->tcps_dev_flow_ctl)
2674                 connp->conn_ixa->ixa_flags |= IXAF_NO_DEV_FLOW_CTL;
2675 
2676         if (isv6) {
2677                 connp->conn_ixa->ixa_src_preferences = IPV6_PREFER_SRC_DEFAULT;
2678                 connp->conn_ipversion = IPV6_VERSION;
2679                 connp->conn_family = AF_INET6;
2680                 tcp->tcp_mss = tcps->tcps_mss_def_ipv6;
2681                 connp->conn_default_ttl = tcps->tcps_ipv6_hoplimit;
2682         } else {
2683                 connp->conn_ipversion = IPV4_VERSION;
2684                 connp->conn_family = AF_INET;
2685                 tcp->tcp_mss = tcps->tcps_mss_def_ipv4;
2686                 connp->conn_default_ttl = tcps->tcps_ipv4_ttl;
2687         }
2688         connp->conn_xmit_ipp.ipp_unicast_hops = connp->conn_default_ttl;
2689 
2690         crhold(credp);
2691         connp->conn_cred = credp;
2692         connp->conn_cpid = curproc->p_pid;
2693         connp->conn_open_time = ddi_get_lbolt64();
2694 
2695         /* Cache things in the ixa without any refhold */
2696         ASSERT(!(connp->conn_ixa->ixa_free_flags & IXA_FREE_CRED));
2697         connp->conn_ixa->ixa_cred = credp;
2698         connp->conn_ixa->ixa_cpid = connp->conn_cpid;
2699 
2700         connp->conn_zoneid = zoneid;
2701         /* conn_allzones can not be set this early, hence no IPCL_ZONEID */
2702         connp->conn_ixa->ixa_zoneid = zoneid;
2703         connp->conn_mlp_type = mlptSingle;
2704         ASSERT(connp->conn_netstack == tcps->tcps_netstack);
2705         ASSERT(tcp->tcp_tcps == tcps);
2706 
2707         /*
2708          * If the caller has the process-wide flag set, then default to MAC
2709          * exempt mode.  This allows read-down to unlabeled hosts.
2710          */
2711         if (getpflags(NET_MAC_AWARE, credp) != 0)
2712                 connp->conn_mac_mode = CONN_MAC_AWARE;
2713 
2714         connp->conn_zone_is_global = (crgetzoneid(credp) == GLOBAL_ZONEID);
2715 
2716         if (issocket) {
2717                 tcp->tcp_issocket = 1;
2718         }
2719 
2720         connp->conn_rcvbuf = tcps->tcps_recv_hiwat;
2721         connp->conn_sndbuf = tcps->tcps_xmit_hiwat;
2722         if (tcps->tcps_snd_lowat_fraction != 0) {
2723                 connp->conn_sndlowat = connp->conn_sndbuf /
2724                     tcps->tcps_snd_lowat_fraction;
2725         } else {
2726                 connp->conn_sndlowat = tcps->tcps_xmit_lowat;
2727         }
2728         connp->conn_so_type = SOCK_STREAM;
2729         connp->conn_wroff = connp->conn_ht_iphc_allocated +
2730             tcps->tcps_wroff_xtra;
2731 
2732         SOCK_CONNID_INIT(tcp->tcp_connid);
2733         /* DTrace ignores this - it isn't a tcp:::state-change */
2734         tcp->tcp_state = TCPS_IDLE;
2735         tcp_init_values(tcp, NULL);
2736         return (connp);
2737 }
2738 
2739 static int
2740 tcp_open(queue_t *q, dev_t *devp, int flag, int sflag, cred_t *credp,
2741     boolean_t isv6)
2742 {
2743         tcp_t           *tcp = NULL;
2744         conn_t          *connp = NULL;
2745         int             err;
2746         vmem_t          *minor_arena = NULL;
2747         dev_t           conn_dev;
2748         boolean_t       issocket;
2749 
2750         if (q->q_ptr != NULL)
2751                 return (0);
2752 
2753         if (sflag == MODOPEN)
2754                 return (EINVAL);
2755 
2756         if ((ip_minor_arena_la != NULL) && (flag & SO_SOCKSTR) &&
2757             ((conn_dev = inet_minor_alloc(ip_minor_arena_la)) != 0)) {
2758                 minor_arena = ip_minor_arena_la;
2759         } else {
2760                 /*
2761                  * Either minor numbers in the large arena were exhausted
2762                  * or a non socket application is doing the open.
2763                  * Try to allocate from the small arena.
2764                  */
2765                 if ((conn_dev = inet_minor_alloc(ip_minor_arena_sa)) == 0) {
2766                         return (EBUSY);
2767                 }
2768                 minor_arena = ip_minor_arena_sa;
2769         }
2770 
2771         ASSERT(minor_arena != NULL);
2772 
2773         *devp = makedevice(getmajor(*devp), (minor_t)conn_dev);
2774 
2775         if (flag & SO_FALLBACK) {
2776                 /*
2777                  * Non streams socket needs a stream to fallback to
2778                  */
2779                 RD(q)->q_ptr = (void *)conn_dev;
2780                 WR(q)->q_qinfo = &tcp_fallback_sock_winit;
2781                 WR(q)->q_ptr = (void *)minor_arena;
2782                 qprocson(q);
2783                 return (0);
2784         } else if (flag & SO_ACCEPTOR) {
2785                 q->q_qinfo = &tcp_acceptor_rinit;
2786                 /*
2787                  * the conn_dev and minor_arena will be subsequently used by
2788                  * tcp_tli_accept() and tcp_tpi_close_accept() to figure out
2789                  * the minor device number for this connection from the q_ptr.
2790                  */
2791                 RD(q)->q_ptr = (void *)conn_dev;
2792                 WR(q)->q_qinfo = &tcp_acceptor_winit;
2793                 WR(q)->q_ptr = (void *)minor_arena;
2794                 qprocson(q);
2795                 return (0);
2796         }
2797 
2798         issocket = flag & SO_SOCKSTR;
2799         connp = tcp_create_common(credp, isv6, issocket, &err);
2800 
2801         if (connp == NULL) {
2802                 inet_minor_free(minor_arena, conn_dev);
2803                 q->q_ptr = WR(q)->q_ptr = NULL;
2804                 return (err);
2805         }
2806 
2807         connp->conn_rq = q;
2808         connp->conn_wq = WR(q);
2809         q->q_ptr = WR(q)->q_ptr = connp;
2810 
2811         connp->conn_dev = conn_dev;
2812         connp->conn_minor_arena = minor_arena;
2813 
2814         ASSERT(q->q_qinfo == &tcp_rinitv4 || q->q_qinfo == &tcp_rinitv6);
2815         ASSERT(WR(q)->q_qinfo == &tcp_winit);
2816 
2817         tcp = connp->conn_tcp;
2818 
2819         if (issocket) {
2820                 WR(q)->q_qinfo = &tcp_sock_winit;
2821         } else {
2822 #ifdef  _ILP32
2823                 tcp->tcp_acceptor_id = (t_uscalar_t)RD(q);
2824 #else
2825                 tcp->tcp_acceptor_id = conn_dev;
2826 #endif  /* _ILP32 */
2827                 tcp_acceptor_hash_insert(tcp->tcp_acceptor_id, tcp);
2828         }
2829 
2830         /*
2831          * Put the ref for TCP. Ref for IP was already put
2832          * by ipcl_conn_create. Also Make the conn_t globally
2833          * visible to walkers
2834          */
2835         mutex_enter(&connp->conn_lock);
2836         CONN_INC_REF_LOCKED(connp);
2837         ASSERT(connp->conn_ref == 2);
2838         connp->conn_state_flags &= ~CONN_INCIPIENT;
2839         mutex_exit(&connp->conn_lock);
2840 
2841         qprocson(q);
2842         return (0);
2843 }
2844 
2845 /*
2846  * Build/update the tcp header template (in conn_ht_iphc) based on
2847  * conn_xmit_ipp. The headers include ip6_t, any extension
2848  * headers, and the maximum size tcp header (to avoid reallocation
2849  * on the fly for additional tcp options).
2850  *
2851  * Assumes the caller has already set conn_{faddr,laddr,fport,lport,flowinfo}.
2852  * Returns failure if can't allocate memory.
2853  */
2854 int
2855 tcp_build_hdrs(tcp_t *tcp)
2856 {
2857         tcp_stack_t     *tcps = tcp->tcp_tcps;
2858         conn_t          *connp = tcp->tcp_connp;
2859         char            buf[TCP_MAX_HDR_LENGTH];
2860         uint_t          buflen;
2861         uint_t          ulplen = TCP_MIN_HEADER_LENGTH;
2862         uint_t          extralen = TCP_MAX_TCP_OPTIONS_LENGTH;
2863         tcpha_t         *tcpha;
2864         uint32_t        cksum;
2865         int             error;
2866 
2867         /*
2868          * We might be called after the connection is set up, and we might
2869          * have TS options already in the TCP header. Thus we  save any
2870          * existing tcp header.
2871          */
2872         buflen = connp->conn_ht_ulp_len;
2873         if (buflen != 0) {
2874                 bcopy(connp->conn_ht_ulp, buf, buflen);
2875                 extralen -= buflen - ulplen;
2876                 ulplen = buflen;
2877         }
2878 
2879         /* Grab lock to satisfy ASSERT; TCP is serialized using squeue */
2880         mutex_enter(&connp->conn_lock);
2881         error = conn_build_hdr_template(connp, ulplen, extralen,
2882             &connp->conn_laddr_v6, &connp->conn_faddr_v6, connp->conn_flowinfo);
2883         mutex_exit(&connp->conn_lock);
2884         if (error != 0)
2885                 return (error);
2886 
2887         /*
2888          * Any routing header/option has been massaged. The checksum difference
2889          * is stored in conn_sum for later use.
2890          */
2891         tcpha = (tcpha_t *)connp->conn_ht_ulp;
2892         tcp->tcp_tcpha = tcpha;
2893 
2894         /* restore any old tcp header */
2895         if (buflen != 0) {
2896                 bcopy(buf, connp->conn_ht_ulp, buflen);
2897         } else {
2898                 tcpha->tha_sum = 0;
2899                 tcpha->tha_urp = 0;
2900                 tcpha->tha_ack = 0;
2901                 tcpha->tha_offset_and_reserved = (5 << 4);
2902                 tcpha->tha_lport = connp->conn_lport;
2903                 tcpha->tha_fport = connp->conn_fport;
2904         }
2905 
2906         /*
2907          * IP wants our header length in the checksum field to
2908          * allow it to perform a single pseudo-header+checksum
2909          * calculation on behalf of TCP.
2910          * Include the adjustment for a source route once IP_OPTIONS is set.
2911          */
2912         cksum = sizeof (tcpha_t) + connp->conn_sum;
2913         cksum = (cksum >> 16) + (cksum & 0xFFFF);
2914         ASSERT(cksum < 0x10000);
2915         tcpha->tha_sum = htons(cksum);
2916 
2917         if (connp->conn_ipversion == IPV4_VERSION)
2918                 tcp->tcp_ipha = (ipha_t *)connp->conn_ht_iphc;
2919         else
2920                 tcp->tcp_ip6h = (ip6_t *)connp->conn_ht_iphc;
2921 
2922         if (connp->conn_ht_iphc_allocated + tcps->tcps_wroff_xtra >
2923             connp->conn_wroff) {
2924                 connp->conn_wroff = connp->conn_ht_iphc_allocated +
2925                     tcps->tcps_wroff_xtra;
2926                 (void) proto_set_tx_wroff(connp->conn_rq, connp,
2927                     connp->conn_wroff);
2928         }
2929         return (0);
2930 }
2931 
2932 /*
2933  * tcp_rwnd_set() is called to adjust the receive window to a desired value.
2934  * We do not allow the receive window to shrink.  After setting rwnd,
2935  * set the flow control hiwat of the stream.
2936  *
2937  * This function is called in 2 cases:
2938  *
2939  * 1) Before data transfer begins, in tcp_input_listener() for accepting a
2940  *    connection (passive open) and in tcp_input_data() for active connect.
2941  *    This is called after tcp_mss_set() when the desired MSS value is known.
2942  *    This makes sure that our window size is a mutiple of the other side's
2943  *    MSS.
2944  * 2) Handling SO_RCVBUF option.
2945  *
2946  * It is ASSUMED that the requested size is a multiple of the current MSS.
2947  *
2948  * XXX - Should allow a lower rwnd than tcp_recv_hiwat_minmss * mss if the
2949  * user requests so.
2950  */
2951 int
2952 tcp_rwnd_set(tcp_t *tcp, uint32_t rwnd)
2953 {
2954         uint32_t        mss = tcp->tcp_mss;
2955         uint32_t        old_max_rwnd;
2956         uint32_t        max_transmittable_rwnd;
2957         boolean_t       tcp_detached = TCP_IS_DETACHED(tcp);
2958         tcp_stack_t     *tcps = tcp->tcp_tcps;
2959         conn_t          *connp = tcp->tcp_connp;
2960 
2961         /*
2962          * Insist on a receive window that is at least
2963          * tcp_recv_hiwat_minmss * MSS (default 4 * MSS) to avoid
2964          * funny TCP interactions of Nagle algorithm, SWS avoidance
2965          * and delayed acknowledgement.
2966          */
2967         rwnd = MAX(rwnd, tcps->tcps_recv_hiwat_minmss * mss);
2968 
2969         if (tcp->tcp_fused) {
2970                 size_t sth_hiwat;
2971                 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
2972 
2973                 ASSERT(peer_tcp != NULL);
2974                 sth_hiwat = tcp_fuse_set_rcv_hiwat(tcp, rwnd);
2975                 if (!tcp_detached) {
2976                         (void) proto_set_rx_hiwat(connp->conn_rq, connp,
2977                             sth_hiwat);
2978                         tcp_set_recv_threshold(tcp, sth_hiwat >> 3);
2979                 }
2980 
2981                 /* Caller could have changed tcp_rwnd; update tha_win */
2982                 if (tcp->tcp_tcpha != NULL) {
2983                         tcp->tcp_tcpha->tha_win =
2984                             htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
2985                 }
2986                 if ((tcp->tcp_rcv_ws > 0) && rwnd > tcp->tcp_cwnd_max)
2987                         tcp->tcp_cwnd_max = rwnd;
2988 
2989                 /*
2990                  * In the fusion case, the maxpsz stream head value of
2991                  * our peer is set according to its send buffer size
2992                  * and our receive buffer size; since the latter may
2993                  * have changed we need to update the peer's maxpsz.
2994                  */
2995                 (void) tcp_maxpsz_set(peer_tcp, B_TRUE);
2996                 return (sth_hiwat);
2997         }
2998 
2999         if (tcp_detached)
3000                 old_max_rwnd = tcp->tcp_rwnd;
3001         else
3002                 old_max_rwnd = connp->conn_rcvbuf;
3003 
3004 
3005         /*
3006          * If window size info has already been exchanged, TCP should not
3007          * shrink the window.  Shrinking window is doable if done carefully.
3008          * We may add that support later.  But so far there is not a real
3009          * need to do that.
3010          */
3011         if (rwnd < old_max_rwnd && tcp->tcp_state > TCPS_SYN_SENT) {
3012                 /* MSS may have changed, do a round up again. */
3013                 rwnd = MSS_ROUNDUP(old_max_rwnd, mss);
3014         }
3015 
3016         /*
3017          * tcp_rcv_ws starts with TCP_MAX_WINSHIFT so the following check
3018          * can be applied even before the window scale option is decided.
3019          */
3020         max_transmittable_rwnd = TCP_MAXWIN << tcp->tcp_rcv_ws;
3021         if (rwnd > max_transmittable_rwnd) {
3022                 rwnd = max_transmittable_rwnd -
3023                     (max_transmittable_rwnd % mss);
3024                 if (rwnd < mss)
3025                         rwnd = max_transmittable_rwnd;
3026                 /*
3027                  * If we're over the limit we may have to back down tcp_rwnd.
3028                  * The increment below won't work for us. So we set all three
3029                  * here and the increment below will have no effect.
3030                  */
3031                 tcp->tcp_rwnd = old_max_rwnd = rwnd;
3032         }
3033         if (tcp->tcp_localnet) {
3034                 tcp->tcp_rack_abs_max =
3035                     MIN(tcps->tcps_local_dacks_max, rwnd / mss / 2);
3036         } else {
3037                 /*
3038                  * For a remote host on a different subnet (through a router),
3039                  * we ack every other packet to be conforming to RFC1122.
3040                  * tcp_deferred_acks_max is default to 2.
3041                  */
3042                 tcp->tcp_rack_abs_max =
3043                     MIN(tcps->tcps_deferred_acks_max, rwnd / mss / 2);
3044         }
3045         if (tcp->tcp_rack_cur_max > tcp->tcp_rack_abs_max)
3046                 tcp->tcp_rack_cur_max = tcp->tcp_rack_abs_max;
3047         else
3048                 tcp->tcp_rack_cur_max = 0;
3049         /*
3050          * Increment the current rwnd by the amount the maximum grew (we
3051          * can not overwrite it since we might be in the middle of a
3052          * connection.)
3053          */
3054         tcp->tcp_rwnd += rwnd - old_max_rwnd;
3055         connp->conn_rcvbuf = rwnd;
3056 
3057         /* Are we already connected? */
3058         if (tcp->tcp_tcpha != NULL) {
3059                 tcp->tcp_tcpha->tha_win =
3060                     htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
3061         }
3062 
3063         if ((tcp->tcp_rcv_ws > 0) && rwnd > tcp->tcp_cwnd_max)
3064                 tcp->tcp_cwnd_max = rwnd;
3065 
3066         if (tcp_detached)
3067                 return (rwnd);
3068 
3069         tcp_set_recv_threshold(tcp, rwnd >> 3);
3070 
3071         (void) proto_set_rx_hiwat(connp->conn_rq, connp, rwnd);
3072         return (rwnd);
3073 }
3074 
3075 int
3076 tcp_do_unbind(conn_t *connp)
3077 {
3078         tcp_t *tcp = connp->conn_tcp;
3079         int32_t oldstate;
3080 
3081         switch (tcp->tcp_state) {
3082         case TCPS_BOUND:
3083         case TCPS_LISTEN:
3084                 break;
3085         default:
3086                 return (-TOUTSTATE);
3087         }
3088 
3089         /*
3090          * Need to clean up all the eagers since after the unbind, segments
3091          * will no longer be delivered to this listener stream.
3092          */
3093         mutex_enter(&tcp->tcp_eager_lock);
3094         if (tcp->tcp_conn_req_cnt_q0 != 0 || tcp->tcp_conn_req_cnt_q != 0) {
3095                 tcp_eager_cleanup(tcp, 0);
3096         }
3097         mutex_exit(&tcp->tcp_eager_lock);
3098 
3099         /* Clean up the listener connection counter if necessary. */
3100         if (tcp->tcp_listen_cnt != NULL)
3101                 TCP_DECR_LISTEN_CNT(tcp);
3102         connp->conn_laddr_v6 = ipv6_all_zeros;
3103         connp->conn_saddr_v6 = ipv6_all_zeros;
3104         tcp_bind_hash_remove(tcp);
3105         oldstate = tcp->tcp_state;
3106         tcp->tcp_state = TCPS_IDLE;
3107         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
3108             connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
3109             int32_t, oldstate);
3110 
3111         ip_unbind(connp);
3112         bzero(&connp->conn_ports, sizeof (connp->conn_ports));
3113 
3114         return (0);
3115 }
3116 
3117 /*
3118  * Collect protocol properties to send to the upper handle.
3119  */
3120 void
3121 tcp_get_proto_props(tcp_t *tcp, struct sock_proto_props *sopp)
3122 {
3123         conn_t *connp = tcp->tcp_connp;
3124 
3125         sopp->sopp_flags = SOCKOPT_RCVHIWAT | SOCKOPT_MAXBLK | SOCKOPT_WROFF;
3126         sopp->sopp_maxblk = tcp_maxpsz_set(tcp, B_FALSE);
3127 
3128         sopp->sopp_rxhiwat = tcp->tcp_fused ?
3129             tcp_fuse_set_rcv_hiwat(tcp, connp->conn_rcvbuf) :
3130             connp->conn_rcvbuf;
3131         /*
3132          * Determine what write offset value to use depending on SACK and
3133          * whether the endpoint is fused or not.
3134          */
3135         if (tcp->tcp_fused) {
3136                 ASSERT(tcp->tcp_loopback);
3137                 ASSERT(tcp->tcp_loopback_peer != NULL);
3138                 /*
3139                  * For fused tcp loopback, set the stream head's write
3140                  * offset value to zero since we won't be needing any room
3141                  * for TCP/IP headers.  This would also improve performance
3142                  * since it would reduce the amount of work done by kmem.
3143                  * Non-fused tcp loopback case is handled separately below.
3144                  */
3145                 sopp->sopp_wroff = 0;
3146                 /*
3147                  * Update the peer's transmit parameters according to
3148                  * our recently calculated high water mark value.
3149                  */
3150                 (void) tcp_maxpsz_set(tcp->tcp_loopback_peer, B_TRUE);
3151         } else if (tcp->tcp_snd_sack_ok) {
3152                 sopp->sopp_wroff = connp->conn_ht_iphc_allocated +
3153                     (tcp->tcp_loopback ? 0 : tcp->tcp_tcps->tcps_wroff_xtra);
3154         } else {
3155                 sopp->sopp_wroff = connp->conn_ht_iphc_len +
3156                     (tcp->tcp_loopback ? 0 : tcp->tcp_tcps->tcps_wroff_xtra);
3157         }
3158 
3159         if (tcp->tcp_loopback) {
3160                 sopp->sopp_flags |= SOCKOPT_LOOPBACK;
3161                 sopp->sopp_loopback = B_TRUE;
3162         }
3163 }
3164 
3165 /*
3166  * Check the usability of ZEROCOPY. It's instead checking the flag set by IP.
3167  */
3168 boolean_t
3169 tcp_zcopy_check(tcp_t *tcp)
3170 {
3171         conn_t          *connp = tcp->tcp_connp;
3172         ip_xmit_attr_t  *ixa = connp->conn_ixa;
3173         boolean_t       zc_enabled = B_FALSE;
3174         tcp_stack_t     *tcps = tcp->tcp_tcps;
3175 
3176         if (do_tcpzcopy == 2)
3177                 zc_enabled = B_TRUE;
3178         else if ((do_tcpzcopy == 1) && (ixa->ixa_flags & IXAF_ZCOPY_CAPAB))
3179                 zc_enabled = B_TRUE;
3180 
3181         tcp->tcp_snd_zcopy_on = zc_enabled;
3182         if (!TCP_IS_DETACHED(tcp)) {
3183                 if (zc_enabled) {
3184                         ixa->ixa_flags |= IXAF_VERIFY_ZCOPY;
3185                         (void) proto_set_tx_copyopt(connp->conn_rq, connp,
3186                             ZCVMSAFE);
3187                         TCP_STAT(tcps, tcp_zcopy_on);
3188                 } else {
3189                         ixa->ixa_flags &= ~IXAF_VERIFY_ZCOPY;
3190                         (void) proto_set_tx_copyopt(connp->conn_rq, connp,
3191                             ZCVMUNSAFE);
3192                         TCP_STAT(tcps, tcp_zcopy_off);
3193                 }
3194         }
3195         return (zc_enabled);
3196 }
3197 
3198 /*
3199  * Backoff from a zero-copy message by copying data to a new allocated
3200  * message and freeing the original desballoca'ed segmapped message.
3201  *
3202  * This function is called by following two callers:
3203  * 1. tcp_timer: fix_xmitlist is set to B_TRUE, because it's safe to free
3204  *    the origial desballoca'ed message and notify sockfs. This is in re-
3205  *    transmit state.
3206  * 2. tcp_output: fix_xmitlist is set to B_FALSE. Flag STRUIO_ZCNOTIFY need
3207  *    to be copied to new message.
3208  */
3209 mblk_t *
3210 tcp_zcopy_backoff(tcp_t *tcp, mblk_t *bp, boolean_t fix_xmitlist)
3211 {
3212         mblk_t          *nbp;
3213         mblk_t          *head = NULL;
3214         mblk_t          *tail = NULL;
3215         tcp_stack_t     *tcps = tcp->tcp_tcps;
3216 
3217         ASSERT(bp != NULL);
3218         while (bp != NULL) {
3219                 if (IS_VMLOANED_MBLK(bp)) {
3220                         TCP_STAT(tcps, tcp_zcopy_backoff);
3221                         if ((nbp = copyb(bp)) == NULL) {
3222                                 tcp->tcp_xmit_zc_clean = B_FALSE;
3223                                 if (tail != NULL)
3224                                         tail->b_cont = bp;
3225                                 return ((head == NULL) ? bp : head);
3226                         }
3227 
3228                         if (bp->b_datap->db_struioflag & STRUIO_ZCNOTIFY) {
3229                                 if (fix_xmitlist)
3230                                         tcp_zcopy_notify(tcp);
3231                                 else
3232                                         nbp->b_datap->db_struioflag |=
3233                                             STRUIO_ZCNOTIFY;
3234                         }
3235                         nbp->b_cont = bp->b_cont;
3236 
3237                         /*
3238                          * Copy saved information and adjust tcp_xmit_tail
3239                          * if needed.
3240                          */
3241                         if (fix_xmitlist) {
3242                                 nbp->b_prev = bp->b_prev;
3243                                 nbp->b_next = bp->b_next;
3244 
3245                                 if (tcp->tcp_xmit_tail == bp)
3246                                         tcp->tcp_xmit_tail = nbp;
3247                         }
3248 
3249                         /* Free the original message. */
3250                         bp->b_prev = NULL;
3251                         bp->b_next = NULL;
3252                         freeb(bp);
3253 
3254                         bp = nbp;
3255                 }
3256 
3257                 if (head == NULL) {
3258                         head = bp;
3259                 }
3260                 if (tail == NULL) {
3261                         tail = bp;
3262                 } else {
3263                         tail->b_cont = bp;
3264                         tail = bp;
3265                 }
3266 
3267                 /* Move forward. */
3268                 bp = bp->b_cont;
3269         }
3270 
3271         if (fix_xmitlist) {
3272                 tcp->tcp_xmit_last = tail;
3273                 tcp->tcp_xmit_zc_clean = B_TRUE;
3274         }
3275 
3276         return (head);
3277 }
3278 
3279 void
3280 tcp_zcopy_notify(tcp_t *tcp)
3281 {
3282         struct stdata   *stp;
3283         conn_t          *connp;
3284 
3285         if (tcp->tcp_detached)
3286                 return;
3287         connp = tcp->tcp_connp;
3288         if (IPCL_IS_NONSTR(connp)) {
3289                 (*connp->conn_upcalls->su_zcopy_notify)
3290                     (connp->conn_upper_handle);
3291                 return;
3292         }
3293         stp = STREAM(connp->conn_rq);
3294         mutex_enter(&stp->sd_lock);
3295         stp->sd_flag |= STZCNOTIFY;
3296         cv_broadcast(&stp->sd_zcopy_wait);
3297         mutex_exit(&stp->sd_lock);
3298 }
3299 
3300 /*
3301  * Update the TCP connection according to change of LSO capability.
3302  */
3303 static void
3304 tcp_update_lso(tcp_t *tcp, ip_xmit_attr_t *ixa)
3305 {
3306         /*
3307          * We check against IPv4 header length to preserve the old behavior
3308          * of only enabling LSO when there are no IP options.
3309          * But this restriction might not be necessary at all. Before removing
3310          * it, need to verify how LSO is handled for source routing case, with
3311          * which IP does software checksum.
3312          *
3313          * For IPv6, whenever any extension header is needed, LSO is supressed.
3314          */
3315         if (ixa->ixa_ip_hdr_length != ((ixa->ixa_flags & IXAF_IS_IPV4) ?
3316             IP_SIMPLE_HDR_LENGTH : IPV6_HDR_LEN))
3317                 return;
3318 
3319         /*
3320          * Either the LSO capability newly became usable, or it has changed.
3321          */
3322         if (ixa->ixa_flags & IXAF_LSO_CAPAB) {
3323                 ill_lso_capab_t *lsoc = &ixa->ixa_lso_capab;
3324 
3325                 ASSERT(lsoc->ill_lso_max > 0);
3326                 tcp->tcp_lso_max = MIN(TCP_MAX_LSO_LENGTH, lsoc->ill_lso_max);
3327 
3328                 DTRACE_PROBE3(tcp_update_lso, boolean_t, tcp->tcp_lso,
3329                     boolean_t, B_TRUE, uint32_t, tcp->tcp_lso_max);
3330 
3331                 /*
3332                  * If LSO to be enabled, notify the STREAM header with larger
3333                  * data block.
3334                  */
3335                 if (!tcp->tcp_lso)
3336                         tcp->tcp_maxpsz_multiplier = 0;
3337 
3338                 tcp->tcp_lso = B_TRUE;
3339                 TCP_STAT(tcp->tcp_tcps, tcp_lso_enabled);
3340         } else { /* LSO capability is not usable any more. */
3341                 DTRACE_PROBE3(tcp_update_lso, boolean_t, tcp->tcp_lso,
3342                     boolean_t, B_FALSE, uint32_t, tcp->tcp_lso_max);
3343 
3344                 /*
3345                  * If LSO to be disabled, notify the STREAM header with smaller
3346                  * data block. And need to restore fragsize to PMTU.
3347                  */
3348                 if (tcp->tcp_lso) {
3349                         tcp->tcp_maxpsz_multiplier =
3350                             tcp->tcp_tcps->tcps_maxpsz_multiplier;
3351                         ixa->ixa_fragsize = ixa->ixa_pmtu;
3352                         tcp->tcp_lso = B_FALSE;
3353                         TCP_STAT(tcp->tcp_tcps, tcp_lso_disabled);
3354                 }
3355         }
3356 
3357         (void) tcp_maxpsz_set(tcp, B_TRUE);
3358 }
3359 
3360 /*
3361  * Update the TCP connection according to change of ZEROCOPY capability.
3362  */
3363 static void
3364 tcp_update_zcopy(tcp_t *tcp)
3365 {
3366         conn_t          *connp = tcp->tcp_connp;
3367         tcp_stack_t     *tcps = tcp->tcp_tcps;
3368 
3369         if (tcp->tcp_snd_zcopy_on) {
3370                 tcp->tcp_snd_zcopy_on = B_FALSE;
3371                 if (!TCP_IS_DETACHED(tcp)) {
3372                         (void) proto_set_tx_copyopt(connp->conn_rq, connp,
3373                             ZCVMUNSAFE);
3374                         TCP_STAT(tcps, tcp_zcopy_off);
3375                 }
3376         } else {
3377                 tcp->tcp_snd_zcopy_on = B_TRUE;
3378                 if (!TCP_IS_DETACHED(tcp)) {
3379                         (void) proto_set_tx_copyopt(connp->conn_rq, connp,
3380                             ZCVMSAFE);
3381                         TCP_STAT(tcps, tcp_zcopy_on);
3382                 }
3383         }
3384 }
3385 
3386 /*
3387  * Notify function registered with ip_xmit_attr_t. It's called in the squeue
3388  * so it's safe to update the TCP connection.
3389  */
3390 /* ARGSUSED1 */
3391 static void
3392 tcp_notify(void *arg, ip_xmit_attr_t *ixa, ixa_notify_type_t ntype,
3393     ixa_notify_arg_t narg)
3394 {
3395         tcp_t           *tcp = (tcp_t *)arg;
3396         conn_t          *connp = tcp->tcp_connp;
3397 
3398         switch (ntype) {
3399         case IXAN_LSO:
3400                 tcp_update_lso(tcp, connp->conn_ixa);
3401                 break;
3402         case IXAN_PMTU:
3403                 tcp_update_pmtu(tcp, B_FALSE);
3404                 break;
3405         case IXAN_ZCOPY:
3406                 tcp_update_zcopy(tcp);
3407                 break;
3408         default:
3409                 break;
3410         }
3411 }
3412 
3413 /*
3414  * The TCP write service routine should never be called...
3415  */
3416 /* ARGSUSED */
3417 static int
3418 tcp_wsrv(queue_t *q)
3419 {
3420         tcp_stack_t     *tcps = Q_TO_TCP(q)->tcp_tcps;
3421 
3422         TCP_STAT(tcps, tcp_wsrv_called);
3423         return (0);
3424 }
3425 
3426 /*
3427  * Hash list lookup routine for tcp_t structures.
3428  * Returns with a CONN_INC_REF tcp structure. Caller must do a CONN_DEC_REF.
3429  */
3430 tcp_t *
3431 tcp_acceptor_hash_lookup(t_uscalar_t id, tcp_stack_t *tcps)
3432 {
3433         tf_t    *tf;
3434         tcp_t   *tcp;
3435 
3436         tf = &tcps->tcps_acceptor_fanout[TCP_ACCEPTOR_HASH(id)];
3437         mutex_enter(&tf->tf_lock);
3438         for (tcp = tf->tf_tcp; tcp != NULL;
3439             tcp = tcp->tcp_acceptor_hash) {
3440                 if (tcp->tcp_acceptor_id == id) {
3441                         CONN_INC_REF(tcp->tcp_connp);
3442                         mutex_exit(&tf->tf_lock);
3443                         return (tcp);
3444                 }
3445         }
3446         mutex_exit(&tf->tf_lock);
3447         return (NULL);
3448 }
3449 
3450 /*
3451  * Hash list insertion routine for tcp_t structures.
3452  */
3453 void
3454 tcp_acceptor_hash_insert(t_uscalar_t id, tcp_t *tcp)
3455 {
3456         tf_t    *tf;
3457         tcp_t   **tcpp;
3458         tcp_t   *tcpnext;
3459         tcp_stack_t     *tcps = tcp->tcp_tcps;
3460 
3461         tf = &tcps->tcps_acceptor_fanout[TCP_ACCEPTOR_HASH(id)];
3462 
3463         if (tcp->tcp_ptpahn != NULL)
3464                 tcp_acceptor_hash_remove(tcp);
3465         tcpp = &tf->tf_tcp;
3466         mutex_enter(&tf->tf_lock);
3467         tcpnext = tcpp[0];
3468         if (tcpnext)
3469                 tcpnext->tcp_ptpahn = &tcp->tcp_acceptor_hash;
3470         tcp->tcp_acceptor_hash = tcpnext;
3471         tcp->tcp_ptpahn = tcpp;
3472         tcpp[0] = tcp;
3473         tcp->tcp_acceptor_lockp = &tf->tf_lock;       /* For tcp_*_hash_remove */
3474         mutex_exit(&tf->tf_lock);
3475 }
3476 
3477 /*
3478  * Hash list removal routine for tcp_t structures.
3479  */
3480 void
3481 tcp_acceptor_hash_remove(tcp_t *tcp)
3482 {
3483         tcp_t   *tcpnext;
3484         kmutex_t *lockp;
3485 
3486         /*
3487          * Extract the lock pointer in case there are concurrent
3488          * hash_remove's for this instance.
3489          */
3490         lockp = tcp->tcp_acceptor_lockp;
3491 
3492         if (tcp->tcp_ptpahn == NULL)
3493                 return;
3494 
3495         ASSERT(lockp != NULL);
3496         mutex_enter(lockp);
3497         if (tcp->tcp_ptpahn) {
3498                 tcpnext = tcp->tcp_acceptor_hash;
3499                 if (tcpnext) {
3500                         tcpnext->tcp_ptpahn = tcp->tcp_ptpahn;
3501                         tcp->tcp_acceptor_hash = NULL;
3502                 }
3503                 *tcp->tcp_ptpahn = tcpnext;
3504                 tcp->tcp_ptpahn = NULL;
3505         }
3506         mutex_exit(lockp);
3507         tcp->tcp_acceptor_lockp = NULL;
3508 }
3509 
3510 /*
3511  * Type three generator adapted from the random() function in 4.4 BSD:
3512  */
3513 
3514 /*
3515  * Copyright (c) 1983, 1993
3516  *      The Regents of the University of California.  All rights reserved.
3517  *
3518  * Redistribution and use in source and binary forms, with or without
3519  * modification, are permitted provided that the following conditions
3520  * are met:
3521  * 1. Redistributions of source code must retain the above copyright
3522  *    notice, this list of conditions and the following disclaimer.
3523  * 2. Redistributions in binary form must reproduce the above copyright
3524  *    notice, this list of conditions and the following disclaimer in the
3525  *    documentation and/or other materials provided with the distribution.
3526  * 3. All advertising materials mentioning features or use of this software
3527  *    must display the following acknowledgement:
3528  *      This product includes software developed by the University of
3529  *      California, Berkeley and its contributors.
3530  * 4. Neither the name of the University nor the names of its contributors
3531  *    may be used to endorse or promote products derived from this software
3532  *    without specific prior written permission.
3533  *
3534  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
3535  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
3536  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
3537  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
3538  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
3539  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
3540  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
3541  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
3542  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
3543  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3544  * SUCH DAMAGE.
3545  */
3546 
3547 /* Type 3 -- x**31 + x**3 + 1 */
3548 #define DEG_3           31
3549 #define SEP_3           3
3550 
3551 
3552 /* Protected by tcp_random_lock */
3553 static int tcp_randtbl[DEG_3 + 1];
3554 
3555 static int *tcp_random_fptr = &tcp_randtbl[SEP_3 + 1];
3556 static int *tcp_random_rptr = &tcp_randtbl[1];
3557 
3558 static int *tcp_random_state = &tcp_randtbl[1];
3559 static int *tcp_random_end_ptr = &tcp_randtbl[DEG_3 + 1];
3560 
3561 kmutex_t tcp_random_lock;
3562 
3563 void
3564 tcp_random_init(void)
3565 {
3566         int i;
3567         hrtime_t hrt;
3568         time_t wallclock;
3569         uint64_t result;
3570 
3571         /*
3572          * Use high-res timer and current time for seed.  Gethrtime() returns
3573          * a longlong, which may contain resolution down to nanoseconds.
3574          * The current time will either be a 32-bit or a 64-bit quantity.
3575          * XOR the two together in a 64-bit result variable.
3576          * Convert the result to a 32-bit value by multiplying the high-order
3577          * 32-bits by the low-order 32-bits.
3578          */
3579 
3580         hrt = gethrtime();
3581         (void) drv_getparm(TIME, &wallclock);
3582         result = (uint64_t)wallclock ^ (uint64_t)hrt;
3583         mutex_enter(&tcp_random_lock);
3584         tcp_random_state[0] = ((result >> 32) & 0xffffffff) *
3585             (result & 0xffffffff);
3586 
3587         for (i = 1; i < DEG_3; i++)
3588                 tcp_random_state[i] = 1103515245 * tcp_random_state[i - 1]
3589                     + 12345;
3590         tcp_random_fptr = &tcp_random_state[SEP_3];
3591         tcp_random_rptr = &tcp_random_state[0];
3592         mutex_exit(&tcp_random_lock);
3593         for (i = 0; i < 10 * DEG_3; i++)
3594                 (void) tcp_random();
3595 }
3596 
3597 /*
3598  * tcp_random: Return a random number in the range [1 - (128K + 1)].
3599  * This range is selected to be approximately centered on TCP_ISS / 2,
3600  * and easy to compute. We get this value by generating a 32-bit random
3601  * number, selecting out the high-order 17 bits, and then adding one so
3602  * that we never return zero.
3603  */
3604 int
3605 tcp_random(void)
3606 {
3607         int i;
3608 
3609         mutex_enter(&tcp_random_lock);
3610         *tcp_random_fptr += *tcp_random_rptr;
3611 
3612         /*
3613          * The high-order bits are more random than the low-order bits,
3614          * so we select out the high-order 17 bits and add one so that
3615          * we never return zero.
3616          */
3617         i = ((*tcp_random_fptr >> 15) & 0x1ffff) + 1;
3618         if (++tcp_random_fptr >= tcp_random_end_ptr) {
3619                 tcp_random_fptr = tcp_random_state;
3620                 ++tcp_random_rptr;
3621         } else if (++tcp_random_rptr >= tcp_random_end_ptr)
3622                 tcp_random_rptr = tcp_random_state;
3623 
3624         mutex_exit(&tcp_random_lock);
3625         return (i);
3626 }
3627 
3628 /*
3629  * Split this function out so that if the secret changes, I'm okay.
3630  *
3631  * Initialize the tcp_iss_cookie and tcp_iss_key.
3632  */
3633 
3634 #define PASSWD_SIZE 16  /* MUST be multiple of 4 */
3635 
3636 void
3637 tcp_iss_key_init(uint8_t *phrase, int len, tcp_stack_t *tcps)
3638 {
3639         struct {
3640                 int32_t current_time;
3641                 uint32_t randnum;
3642                 uint16_t pad;
3643                 uint8_t ether[6];
3644                 uint8_t passwd[PASSWD_SIZE];
3645         } tcp_iss_cookie;
3646         time_t t;
3647 
3648         /*
3649          * Start with the current absolute time.
3650          */
3651         (void) drv_getparm(TIME, &t);
3652         tcp_iss_cookie.current_time = t;
3653 
3654         /*
3655          * XXX - Need a more random number per RFC 1750, not this crap.
3656          * OTOH, if what follows is pretty random, then I'm in better shape.
3657          */
3658         tcp_iss_cookie.randnum = (uint32_t)(gethrtime() + tcp_random());
3659         tcp_iss_cookie.pad = 0x365c;  /* Picked from HMAC pad values. */
3660 
3661         /*
3662          * The cpu_type_info is pretty non-random.  Ugggh.  It does serve
3663          * as a good template.
3664          */
3665         bcopy(&cpu_list->cpu_type_info, &tcp_iss_cookie.passwd,
3666             min(PASSWD_SIZE, sizeof (cpu_list->cpu_type_info)));
3667 
3668         /*
3669          * The pass-phrase.  Normally this is supplied by user-called NDD.
3670          */
3671         bcopy(phrase, &tcp_iss_cookie.passwd, min(PASSWD_SIZE, len));
3672 
3673         /*
3674          * See 4010593 if this section becomes a problem again,
3675          * but the local ethernet address is useful here.
3676          */
3677         (void) localetheraddr(NULL,
3678             (struct ether_addr *)&tcp_iss_cookie.ether);
3679 
3680         /*
3681          * Hash 'em all together.  The MD5Final is called per-connection.
3682          */
3683         mutex_enter(&tcps->tcps_iss_key_lock);
3684         MD5Init(&tcps->tcps_iss_key);
3685         MD5Update(&tcps->tcps_iss_key, (uchar_t *)&tcp_iss_cookie,
3686             sizeof (tcp_iss_cookie));
3687         mutex_exit(&tcps->tcps_iss_key_lock);
3688 }
3689 
3690 /*
3691  * Called by IP when IP is loaded into the kernel
3692  */
3693 void
3694 tcp_ddi_g_init(void)
3695 {
3696         tcp_timercache = kmem_cache_create("tcp_timercache",
3697             sizeof (tcp_timer_t) + sizeof (mblk_t), 0,
3698             NULL, NULL, NULL, NULL, NULL, 0);
3699 
3700         tcp_notsack_blk_cache = kmem_cache_create("tcp_notsack_blk_cache",
3701             sizeof (notsack_blk_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
3702 
3703         mutex_init(&tcp_random_lock, NULL, MUTEX_DEFAULT, NULL);
3704 
3705         /* Initialize the random number generator */
3706         tcp_random_init();
3707 
3708         /* A single callback independently of how many netstacks we have */
3709         ip_squeue_init(tcp_squeue_add);
3710 
3711         tcp_g_kstat = tcp_g_kstat_init(&tcp_g_statistics);
3712 
3713         tcp_squeue_flag = tcp_squeue_switch(tcp_squeue_wput);
3714 
3715         /*
3716          * We want to be informed each time a stack is created or
3717          * destroyed in the kernel, so we can maintain the
3718          * set of tcp_stack_t's.
3719          */
3720         netstack_register(NS_TCP, tcp_stack_init, NULL, tcp_stack_fini);
3721 }
3722 
3723 
3724 #define INET_NAME       "ip"
3725 
3726 /*
3727  * Initialize the TCP stack instance.
3728  */
3729 static void *
3730 tcp_stack_init(netstackid_t stackid, netstack_t *ns)
3731 {
3732         tcp_stack_t     *tcps;
3733         int             i;
3734         int             error = 0;
3735         major_t         major;
3736         size_t          arrsz;
3737 
3738         tcps = (tcp_stack_t *)kmem_zalloc(sizeof (*tcps), KM_SLEEP);
3739         tcps->tcps_netstack = ns;
3740 
3741         /* Initialize locks */
3742         mutex_init(&tcps->tcps_iss_key_lock, NULL, MUTEX_DEFAULT, NULL);
3743         mutex_init(&tcps->tcps_epriv_port_lock, NULL, MUTEX_DEFAULT, NULL);
3744 
3745         tcps->tcps_g_num_epriv_ports = TCP_NUM_EPRIV_PORTS;
3746         tcps->tcps_g_epriv_ports[0] = ULP_DEF_EPRIV_PORT1;
3747         tcps->tcps_g_epriv_ports[1] = ULP_DEF_EPRIV_PORT2;
3748         tcps->tcps_min_anonpriv_port = 512;
3749 
3750         tcps->tcps_bind_fanout = kmem_zalloc(sizeof (tf_t) *
3751             TCP_BIND_FANOUT_SIZE, KM_SLEEP);
3752         tcps->tcps_acceptor_fanout = kmem_zalloc(sizeof (tf_t) *
3753             TCP_ACCEPTOR_FANOUT_SIZE, KM_SLEEP);
3754 
3755         for (i = 0; i < TCP_BIND_FANOUT_SIZE; i++) {
3756                 mutex_init(&tcps->tcps_bind_fanout[i].tf_lock, NULL,
3757                     MUTEX_DEFAULT, NULL);
3758         }
3759 
3760         for (i = 0; i < TCP_ACCEPTOR_FANOUT_SIZE; i++) {
3761                 mutex_init(&tcps->tcps_acceptor_fanout[i].tf_lock, NULL,
3762                     MUTEX_DEFAULT, NULL);
3763         }
3764 
3765         /* TCP's IPsec code calls the packet dropper. */
3766         ip_drop_register(&tcps->tcps_dropper, "TCP IPsec policy enforcement");
3767 
3768         arrsz = tcp_propinfo_count * sizeof (mod_prop_info_t);
3769         tcps->tcps_propinfo_tbl = (mod_prop_info_t *)kmem_alloc(arrsz,
3770             KM_SLEEP);
3771         bcopy(tcp_propinfo_tbl, tcps->tcps_propinfo_tbl, arrsz);
3772 
3773         /*
3774          * Note: To really walk the device tree you need the devinfo
3775          * pointer to your device which is only available after probe/attach.
3776          * The following is safe only because it uses ddi_root_node()
3777          */
3778         tcp_max_optsize = optcom_max_optsize(tcp_opt_obj.odb_opt_des_arr,
3779             tcp_opt_obj.odb_opt_arr_cnt);
3780 
3781         /*
3782          * Initialize RFC 1948 secret values.  This will probably be reset once
3783          * by the boot scripts.
3784          *
3785          * Use NULL name, as the name is caught by the new lockstats.
3786          *
3787          * Initialize with some random, non-guessable string, like the global
3788          * T_INFO_ACK.
3789          */
3790 
3791         tcp_iss_key_init((uint8_t *)&tcp_g_t_info_ack,
3792             sizeof (tcp_g_t_info_ack), tcps);
3793 
3794         tcps->tcps_kstat = tcp_kstat2_init(stackid);
3795         tcps->tcps_mibkp = tcp_kstat_init(stackid);
3796 
3797         major = mod_name_to_major(INET_NAME);
3798         error = ldi_ident_from_major(major, &tcps->tcps_ldi_ident);
3799         ASSERT(error == 0);
3800         tcps->tcps_ixa_cleanup_mp = allocb_wait(0, BPRI_MED, STR_NOSIG, NULL);
3801         ASSERT(tcps->tcps_ixa_cleanup_mp != NULL);
3802         cv_init(&tcps->tcps_ixa_cleanup_ready_cv, NULL, CV_DEFAULT, NULL);
3803         cv_init(&tcps->tcps_ixa_cleanup_done_cv, NULL, CV_DEFAULT, NULL);
3804         mutex_init(&tcps->tcps_ixa_cleanup_lock, NULL, MUTEX_DEFAULT, NULL);
3805 
3806         mutex_init(&tcps->tcps_reclaim_lock, NULL, MUTEX_DEFAULT, NULL);
3807         tcps->tcps_reclaim = B_FALSE;
3808         tcps->tcps_reclaim_tid = 0;
3809         tcps->tcps_reclaim_period = tcps->tcps_rexmit_interval_max;
3810 
3811         /*
3812          * ncpus is the current number of CPUs, which can be bigger than
3813          * boot_ncpus.  But we don't want to use ncpus to allocate all the
3814          * tcp_stats_cpu_t at system boot up time since it will be 1.  While
3815          * we handle adding CPU in tcp_cpu_update(), it will be slow if
3816          * there are many CPUs as we will be adding them 1 by 1.
3817          *
3818          * Note that tcps_sc_cnt never decreases and the tcps_sc[x] pointers
3819          * are not freed until the stack is going away.  So there is no need
3820          * to grab a lock to access the per CPU tcps_sc[x] pointer.
3821          */
3822         mutex_enter(&cpu_lock);
3823         tcps->tcps_sc_cnt = MAX(ncpus, boot_ncpus);
3824         mutex_exit(&cpu_lock);
3825         tcps->tcps_sc = kmem_zalloc(max_ncpus  * sizeof (tcp_stats_cpu_t *),
3826             KM_SLEEP);
3827         for (i = 0; i < tcps->tcps_sc_cnt; i++) {
3828                 tcps->tcps_sc[i] = kmem_zalloc(sizeof (tcp_stats_cpu_t),
3829                     KM_SLEEP);
3830         }
3831 
3832         mutex_init(&tcps->tcps_listener_conf_lock, NULL, MUTEX_DEFAULT, NULL);
3833         list_create(&tcps->tcps_listener_conf, sizeof (tcp_listener_t),
3834             offsetof(tcp_listener_t, tl_link));
3835 
3836         return (tcps);
3837 }
3838 
3839 /*
3840  * Called when the IP module is about to be unloaded.
3841  */
3842 void
3843 tcp_ddi_g_destroy(void)
3844 {
3845         tcp_g_kstat_fini(tcp_g_kstat);
3846         tcp_g_kstat = NULL;
3847         bzero(&tcp_g_statistics, sizeof (tcp_g_statistics));
3848 
3849         mutex_destroy(&tcp_random_lock);
3850 
3851         kmem_cache_destroy(tcp_timercache);
3852         kmem_cache_destroy(tcp_notsack_blk_cache);
3853 
3854         netstack_unregister(NS_TCP);
3855 }
3856 
3857 /*
3858  * Free the TCP stack instance.
3859  */
3860 static void
3861 tcp_stack_fini(netstackid_t stackid, void *arg)
3862 {
3863         tcp_stack_t *tcps = (tcp_stack_t *)arg;
3864         int i;
3865 
3866         freeb(tcps->tcps_ixa_cleanup_mp);
3867         tcps->tcps_ixa_cleanup_mp = NULL;
3868         cv_destroy(&tcps->tcps_ixa_cleanup_ready_cv);
3869         cv_destroy(&tcps->tcps_ixa_cleanup_done_cv);
3870         mutex_destroy(&tcps->tcps_ixa_cleanup_lock);
3871 
3872         /*
3873          * Set tcps_reclaim to false tells tcp_reclaim_timer() not to restart
3874          * the timer.
3875          */
3876         mutex_enter(&tcps->tcps_reclaim_lock);
3877         tcps->tcps_reclaim = B_FALSE;
3878         mutex_exit(&tcps->tcps_reclaim_lock);
3879         if (tcps->tcps_reclaim_tid != 0)
3880                 (void) untimeout(tcps->tcps_reclaim_tid);
3881         mutex_destroy(&tcps->tcps_reclaim_lock);
3882 
3883         tcp_listener_conf_cleanup(tcps);
3884 
3885         for (i = 0; i < tcps->tcps_sc_cnt; i++)
3886                 kmem_free(tcps->tcps_sc[i], sizeof (tcp_stats_cpu_t));
3887         kmem_free(tcps->tcps_sc, max_ncpus * sizeof (tcp_stats_cpu_t *));
3888 
3889         kmem_free(tcps->tcps_propinfo_tbl,
3890             tcp_propinfo_count * sizeof (mod_prop_info_t));
3891         tcps->tcps_propinfo_tbl = NULL;
3892 
3893         for (i = 0; i < TCP_BIND_FANOUT_SIZE; i++) {
3894                 ASSERT(tcps->tcps_bind_fanout[i].tf_tcp == NULL);
3895                 mutex_destroy(&tcps->tcps_bind_fanout[i].tf_lock);
3896         }
3897 
3898         for (i = 0; i < TCP_ACCEPTOR_FANOUT_SIZE; i++) {
3899                 ASSERT(tcps->tcps_acceptor_fanout[i].tf_tcp == NULL);
3900                 mutex_destroy(&tcps->tcps_acceptor_fanout[i].tf_lock);
3901         }
3902 
3903         kmem_free(tcps->tcps_bind_fanout, sizeof (tf_t) * TCP_BIND_FANOUT_SIZE);
3904         tcps->tcps_bind_fanout = NULL;
3905 
3906         kmem_free(tcps->tcps_acceptor_fanout, sizeof (tf_t) *
3907             TCP_ACCEPTOR_FANOUT_SIZE);
3908         tcps->tcps_acceptor_fanout = NULL;
3909 
3910         mutex_destroy(&tcps->tcps_iss_key_lock);
3911         mutex_destroy(&tcps->tcps_epriv_port_lock);
3912 
3913         ip_drop_unregister(&tcps->tcps_dropper);
3914 
3915         tcp_kstat2_fini(stackid, tcps->tcps_kstat);
3916         tcps->tcps_kstat = NULL;
3917 
3918         tcp_kstat_fini(stackid, tcps->tcps_mibkp);
3919         tcps->tcps_mibkp = NULL;
3920 
3921         ldi_ident_release(tcps->tcps_ldi_ident);
3922         kmem_free(tcps, sizeof (*tcps));
3923 }
3924 
3925 /*
3926  * Generate ISS, taking into account NDD changes may happen halfway through.
3927  * (If the iss is not zero, set it.)
3928  */
3929 
3930 static void
3931 tcp_iss_init(tcp_t *tcp)
3932 {
3933         MD5_CTX context;
3934         struct { uint32_t ports; in6_addr_t src; in6_addr_t dst; } arg;
3935         uint32_t answer[4];
3936         tcp_stack_t     *tcps = tcp->tcp_tcps;
3937         conn_t          *connp = tcp->tcp_connp;
3938 
3939         tcps->tcps_iss_incr_extra += (tcps->tcps_iss_incr >> 1);
3940         tcp->tcp_iss = tcps->tcps_iss_incr_extra;
3941         switch (tcps->tcps_strong_iss) {
3942         case 2:
3943                 mutex_enter(&tcps->tcps_iss_key_lock);
3944                 context = tcps->tcps_iss_key;
3945                 mutex_exit(&tcps->tcps_iss_key_lock);
3946                 arg.ports = connp->conn_ports;
3947                 arg.src = connp->conn_laddr_v6;
3948                 arg.dst = connp->conn_faddr_v6;
3949                 MD5Update(&context, (uchar_t *)&arg, sizeof (arg));
3950                 MD5Final((uchar_t *)answer, &context);
3951                 tcp->tcp_iss += answer[0] ^ answer[1] ^ answer[2] ^ answer[3];
3952                 /*
3953                  * Now that we've hashed into a unique per-connection sequence
3954                  * space, add a random increment per strong_iss == 1.  So I
3955                  * guess we'll have to...
3956                  */
3957                 /* FALLTHRU */
3958         case 1:
3959                 tcp->tcp_iss += (gethrtime() >> ISS_NSEC_SHT) + tcp_random();
3960                 break;
3961         default:
3962                 tcp->tcp_iss += (uint32_t)gethrestime_sec() *
3963                     tcps->tcps_iss_incr;
3964                 break;
3965         }
3966         tcp->tcp_valid_bits = TCP_ISS_VALID;
3967         tcp->tcp_fss = tcp->tcp_iss - 1;
3968         tcp->tcp_suna = tcp->tcp_iss;
3969         tcp->tcp_snxt = tcp->tcp_iss + 1;
3970         tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
3971         tcp->tcp_csuna = tcp->tcp_snxt;
3972 }
3973 
3974 /*
3975  * tcp_{set,clr}qfull() functions are used to either set or clear QFULL
3976  * on the specified backing STREAMS q. Note, the caller may make the
3977  * decision to call based on the tcp_t.tcp_flow_stopped value which
3978  * when check outside the q's lock is only an advisory check ...
3979  */
3980 void
3981 tcp_setqfull(tcp_t *tcp)
3982 {
3983         tcp_stack_t     *tcps = tcp->tcp_tcps;
3984         conn_t  *connp = tcp->tcp_connp;
3985 
3986         if (tcp->tcp_closed)
3987                 return;
3988 
3989         conn_setqfull(connp, &tcp->tcp_flow_stopped);
3990         if (tcp->tcp_flow_stopped)
3991                 TCP_STAT(tcps, tcp_flwctl_on);
3992 }
3993 
3994 void
3995 tcp_clrqfull(tcp_t *tcp)
3996 {
3997         conn_t  *connp = tcp->tcp_connp;
3998 
3999         if (tcp->tcp_closed)
4000                 return;
4001         conn_clrqfull(connp, &tcp->tcp_flow_stopped);
4002 }
4003 
4004 static int
4005 tcp_squeue_switch(int val)
4006 {
4007         int rval = SQ_FILL;
4008 
4009         switch (val) {
4010         case 1:
4011                 rval = SQ_NODRAIN;
4012                 break;
4013         case 2:
4014                 rval = SQ_PROCESS;
4015                 break;
4016         default:
4017                 break;
4018         }
4019         return (rval);
4020 }
4021 
4022 /*
4023  * This is called once for each squeue - globally for all stack
4024  * instances.
4025  */
4026 static void
4027 tcp_squeue_add(squeue_t *sqp)
4028 {
4029         tcp_squeue_priv_t *tcp_time_wait = kmem_zalloc(
4030             sizeof (tcp_squeue_priv_t), KM_SLEEP);
4031 
4032         *squeue_getprivate(sqp, SQPRIVATE_TCP) = (intptr_t)tcp_time_wait;
4033         if (tcp_free_list_max_cnt == 0) {
4034                 int tcp_ncpus = ((boot_max_ncpus == -1) ?
4035                     max_ncpus : boot_max_ncpus);
4036 
4037                 /*
4038                  * Limit number of entries to 1% of availble memory / tcp_ncpus
4039                  */
4040                 tcp_free_list_max_cnt = (freemem * PAGESIZE) /
4041                     (tcp_ncpus * sizeof (tcp_t) * 100);
4042         }
4043         tcp_time_wait->tcp_free_list_cnt = 0;
4044 }
4045 /*
4046  * Return unix error is tli error is TSYSERR, otherwise return a negative
4047  * tli error.
4048  */
4049 int
4050 tcp_do_bind(conn_t *connp, struct sockaddr *sa, socklen_t len, cred_t *cr,
4051     boolean_t bind_to_req_port_only)
4052 {
4053         int error;
4054         tcp_t *tcp = connp->conn_tcp;
4055 
4056         if (tcp->tcp_state >= TCPS_BOUND) {
4057                 if (connp->conn_debug) {
4058                         (void) strlog(TCP_MOD_ID, 0, 1, SL_ERROR|SL_TRACE,
4059                             "tcp_bind: bad state, %d", tcp->tcp_state);
4060                 }
4061                 return (-TOUTSTATE);
4062         }
4063 
4064         error = tcp_bind_check(connp, sa, len, cr, bind_to_req_port_only);
4065         if (error != 0)
4066                 return (error);
4067 
4068         ASSERT(tcp->tcp_state == TCPS_BOUND);
4069         tcp->tcp_conn_req_max = 0;
4070         return (0);
4071 }
4072 
4073 /*
4074  * If the return value from this function is positive, it's a UNIX error.
4075  * Otherwise, if it's negative, then the absolute value is a TLI error.
4076  * the TPI routine tcp_tpi_connect() is a wrapper function for this.
4077  */
4078 int
4079 tcp_do_connect(conn_t *connp, const struct sockaddr *sa, socklen_t len,
4080     cred_t *cr, pid_t pid)
4081 {
4082         tcp_t           *tcp = connp->conn_tcp;
4083         sin_t           *sin = (sin_t *)sa;
4084         sin6_t          *sin6 = (sin6_t *)sa;
4085         ipaddr_t        *dstaddrp;
4086         in_port_t       dstport;
4087         uint_t          srcid;
4088         int             error;
4089         uint32_t        mss;
4090         mblk_t          *syn_mp;
4091         tcp_stack_t     *tcps = tcp->tcp_tcps;
4092         int32_t         oldstate;
4093         ip_xmit_attr_t  *ixa = connp->conn_ixa;
4094 
4095         oldstate = tcp->tcp_state;
4096 
4097         switch (len) {
4098         default:
4099                 /*
4100                  * Should never happen
4101                  */
4102                 return (EINVAL);
4103 
4104         case sizeof (sin_t):
4105                 sin = (sin_t *)sa;
4106                 if (sin->sin_port == 0) {
4107                         return (-TBADADDR);
4108                 }
4109                 if (connp->conn_ipv6_v6only) {
4110                         return (EAFNOSUPPORT);
4111                 }
4112                 break;
4113 
4114         case sizeof (sin6_t):
4115                 sin6 = (sin6_t *)sa;
4116                 if (sin6->sin6_port == 0) {
4117                         return (-TBADADDR);
4118                 }
4119                 break;
4120         }
4121         /*
4122          * If we're connecting to an IPv4-mapped IPv6 address, we need to
4123          * make sure that the conn_ipversion is IPV4_VERSION.  We
4124          * need to this before we call tcp_bindi() so that the port lookup
4125          * code will look for ports in the correct port space (IPv4 and
4126          * IPv6 have separate port spaces).
4127          */
4128         if (connp->conn_family == AF_INET6 &&
4129             connp->conn_ipversion == IPV6_VERSION &&
4130             IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
4131                 if (connp->conn_ipv6_v6only)
4132                         return (EADDRNOTAVAIL);
4133 
4134                 connp->conn_ipversion = IPV4_VERSION;
4135         }
4136 
4137         switch (tcp->tcp_state) {
4138         case TCPS_LISTEN:
4139                 /*
4140                  * Listening sockets are not allowed to issue connect().
4141                  */
4142                 if (IPCL_IS_NONSTR(connp))
4143                         return (EOPNOTSUPP);
4144                 /* FALLTHRU */
4145         case TCPS_IDLE:
4146                 /*
4147                  * We support quick connect, refer to comments in
4148                  * tcp_connect_*()
4149                  */
4150                 /* FALLTHRU */
4151         case TCPS_BOUND:
4152                 break;
4153         default:
4154                 return (-TOUTSTATE);
4155         }
4156 
4157         /*
4158          * We update our cred/cpid based on the caller of connect
4159          */
4160         if (connp->conn_cred != cr) {
4161                 crhold(cr);
4162                 crfree(connp->conn_cred);
4163                 connp->conn_cred = cr;
4164         }
4165         connp->conn_cpid = pid;
4166 
4167         /* Cache things in the ixa without any refhold */
4168         ASSERT(!(ixa->ixa_free_flags & IXA_FREE_CRED));
4169         ixa->ixa_cred = cr;
4170         ixa->ixa_cpid = pid;
4171         if (is_system_labeled()) {
4172                 /* We need to restart with a label based on the cred */
4173                 ip_xmit_attr_restore_tsl(ixa, ixa->ixa_cred);
4174         }
4175 
4176         if (connp->conn_family == AF_INET6) {
4177                 if (!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
4178                         error = tcp_connect_ipv6(tcp, &sin6->sin6_addr,
4179                             sin6->sin6_port, sin6->sin6_flowinfo,
4180                             sin6->__sin6_src_id, sin6->sin6_scope_id);
4181                 } else {
4182                         /*
4183                          * Destination adress is mapped IPv6 address.
4184                          * Source bound address should be unspecified or
4185                          * IPv6 mapped address as well.
4186                          */
4187                         if (!IN6_IS_ADDR_UNSPECIFIED(
4188                             &connp->conn_bound_addr_v6) &&
4189                             !IN6_IS_ADDR_V4MAPPED(&connp->conn_bound_addr_v6)) {
4190                                 return (EADDRNOTAVAIL);
4191                         }
4192                         dstaddrp = &V4_PART_OF_V6((sin6->sin6_addr));
4193                         dstport = sin6->sin6_port;
4194                         srcid = sin6->__sin6_src_id;
4195                         error = tcp_connect_ipv4(tcp, dstaddrp, dstport,
4196                             srcid);
4197                 }
4198         } else {
4199                 dstaddrp = &sin->sin_addr.s_addr;
4200                 dstport = sin->sin_port;
4201                 srcid = 0;
4202                 error = tcp_connect_ipv4(tcp, dstaddrp, dstport, srcid);
4203         }
4204 
4205         if (error != 0)
4206                 goto connect_failed;
4207 
4208         CL_INET_CONNECT(connp, B_TRUE, error);
4209         if (error != 0)
4210                 goto connect_failed;
4211 
4212         /* connect succeeded */
4213         TCPS_BUMP_MIB(tcps, tcpActiveOpens);
4214         tcp->tcp_active_open = 1;
4215 
4216         /*
4217          * tcp_set_destination() does not adjust for TCP/IP header length.
4218          */
4219         mss = tcp->tcp_mss - connp->conn_ht_iphc_len;
4220 
4221         /*
4222          * Just make sure our rwnd is at least rcvbuf * MSS large, and round up
4223          * to the nearest MSS.
4224          *
4225          * We do the round up here because we need to get the interface MTU
4226          * first before we can do the round up.
4227          */
4228         tcp->tcp_rwnd = connp->conn_rcvbuf;
4229         tcp->tcp_rwnd = MAX(MSS_ROUNDUP(tcp->tcp_rwnd, mss),
4230             tcps->tcps_recv_hiwat_minmss * mss);
4231         connp->conn_rcvbuf = tcp->tcp_rwnd;
4232         tcp_set_ws_value(tcp);
4233         tcp->tcp_tcpha->tha_win = htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
4234         if (tcp->tcp_rcv_ws > 0 || tcps->tcps_wscale_always)
4235                 tcp->tcp_snd_ws_ok = B_TRUE;
4236 
4237         /*
4238          * Set tcp_snd_ts_ok to true
4239          * so that tcp_xmit_mp will
4240          * include the timestamp
4241          * option in the SYN segment.
4242          */
4243         if (tcps->tcps_tstamp_always ||
4244             (tcp->tcp_rcv_ws && tcps->tcps_tstamp_if_wscale)) {
4245                 tcp->tcp_snd_ts_ok = B_TRUE;
4246         }
4247 
4248         /*
4249          * Note that tcp_snd_sack_ok can be set in tcp_set_destination() if
4250          * the SACK metric is set.  So here we just check the per stack SACK
4251          * permitted param.
4252          */
4253         if (tcps->tcps_sack_permitted == 2) {
4254                 ASSERT(tcp->tcp_num_sack_blk == 0);
4255                 ASSERT(tcp->tcp_notsack_list == NULL);
4256                 tcp->tcp_snd_sack_ok = B_TRUE;
4257         }
4258 
4259         /*
4260          * Should we use ECN?  Note that the current
4261          * default value (SunOS 5.9) of tcp_ecn_permitted
4262          * is 1.  The reason for doing this is that there
4263          * are equipments out there that will drop ECN
4264          * enabled IP packets.  Setting it to 1 avoids
4265          * compatibility problems.
4266          */
4267         if (tcps->tcps_ecn_permitted == 2)
4268                 tcp->tcp_ecn_ok = B_TRUE;
4269 
4270         /* Trace change from BOUND -> SYN_SENT here */
4271         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
4272             connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
4273             int32_t, TCPS_BOUND);
4274 
4275         TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
4276         syn_mp = tcp_xmit_mp(tcp, NULL, 0, NULL, NULL,
4277             tcp->tcp_iss, B_FALSE, NULL, B_FALSE);
4278         if (syn_mp != NULL) {
4279                 /*
4280                  * We must bump the generation before sending the syn
4281                  * to ensure that we use the right generation in case
4282                  * this thread issues a "connected" up call.
4283                  */
4284                 SOCK_CONNID_BUMP(tcp->tcp_connid);
4285                 /*
4286                  * DTrace sending the first SYN as a
4287                  * tcp:::connect-request event.
4288                  */
4289                 DTRACE_TCP5(connect__request, mblk_t *, NULL,
4290                     ip_xmit_attr_t *, connp->conn_ixa,
4291                     void_ip_t *, syn_mp->b_rptr, tcp_t *, tcp,
4292                     tcph_t *,
4293                     &syn_mp->b_rptr[connp->conn_ixa->ixa_ip_hdr_length]);
4294                 tcp_send_data(tcp, syn_mp);
4295         }
4296 
4297         if (tcp->tcp_conn.tcp_opts_conn_req != NULL)
4298                 tcp_close_mpp(&tcp->tcp_conn.tcp_opts_conn_req);
4299         return (0);
4300 
4301 connect_failed:
4302         connp->conn_faddr_v6 = ipv6_all_zeros;
4303         connp->conn_fport = 0;
4304         tcp->tcp_state = oldstate;
4305         if (tcp->tcp_conn.tcp_opts_conn_req != NULL)
4306                 tcp_close_mpp(&tcp->tcp_conn.tcp_opts_conn_req);
4307         return (error);
4308 }
4309 
4310 int
4311 tcp_do_listen(conn_t *connp, struct sockaddr *sa, socklen_t len,
4312     int backlog, cred_t *cr, boolean_t bind_to_req_port_only)
4313 {
4314         tcp_t           *tcp = connp->conn_tcp;
4315         int             error = 0;
4316         tcp_stack_t     *tcps = tcp->tcp_tcps;
4317         int32_t         oldstate;
4318 
4319         /* All Solaris components should pass a cred for this operation. */
4320         ASSERT(cr != NULL);
4321 
4322         if (tcp->tcp_state >= TCPS_BOUND) {
4323                 if ((tcp->tcp_state == TCPS_BOUND ||
4324                     tcp->tcp_state == TCPS_LISTEN) && backlog > 0) {
4325                         /*
4326                          * Handle listen() increasing backlog.
4327                          * This is more "liberal" then what the TPI spec
4328                          * requires but is needed to avoid a t_unbind
4329                          * when handling listen() since the port number
4330                          * might be "stolen" between the unbind and bind.
4331                          */
4332                         goto do_listen;
4333                 }
4334                 if (connp->conn_debug) {
4335                         (void) strlog(TCP_MOD_ID, 0, 1, SL_ERROR|SL_TRACE,
4336                             "tcp_listen: bad state, %d", tcp->tcp_state);
4337                 }
4338                 return (-TOUTSTATE);
4339         } else {
4340                 if (sa == NULL) {
4341                         sin6_t  addr;
4342                         sin_t *sin;
4343                         sin6_t *sin6;
4344 
4345                         ASSERT(IPCL_IS_NONSTR(connp));
4346                         /* Do an implicit bind: Request for a generic port. */
4347                         if (connp->conn_family == AF_INET) {
4348                                 len = sizeof (sin_t);
4349                                 sin = (sin_t *)&addr;
4350                                 *sin = sin_null;
4351                                 sin->sin_family = AF_INET;
4352                         } else {
4353                                 ASSERT(connp->conn_family == AF_INET6);
4354                                 len = sizeof (sin6_t);
4355                                 sin6 = (sin6_t *)&addr;
4356                                 *sin6 = sin6_null;
4357                                 sin6->sin6_family = AF_INET6;
4358                         }
4359                         sa = (struct sockaddr *)&addr;
4360                 }
4361 
4362                 error = tcp_bind_check(connp, sa, len, cr,
4363                     bind_to_req_port_only);
4364                 if (error)
4365                         return (error);
4366                 /* Fall through and do the fanout insertion */
4367         }
4368 
4369 do_listen:
4370         ASSERT(tcp->tcp_state == TCPS_BOUND || tcp->tcp_state == TCPS_LISTEN);
4371         tcp->tcp_conn_req_max = backlog;
4372         if (tcp->tcp_conn_req_max) {
4373                 if (tcp->tcp_conn_req_max < tcps->tcps_conn_req_min)
4374                         tcp->tcp_conn_req_max = tcps->tcps_conn_req_min;
4375                 if (tcp->tcp_conn_req_max > tcps->tcps_conn_req_max_q)
4376                         tcp->tcp_conn_req_max = tcps->tcps_conn_req_max_q;
4377                 /*
4378                  * If this is a listener, do not reset the eager list
4379                  * and other stuffs.  Note that we don't check if the
4380                  * existing eager list meets the new tcp_conn_req_max
4381                  * requirement.
4382                  */
4383                 if (tcp->tcp_state != TCPS_LISTEN) {
4384                         tcp->tcp_state = TCPS_LISTEN;
4385                         DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
4386                             connp->conn_ixa, void, NULL, tcp_t *, tcp,
4387                             void, NULL, int32_t, TCPS_BOUND);
4388                         /* Initialize the chain. Don't need the eager_lock */
4389                         tcp->tcp_eager_next_q0 = tcp->tcp_eager_prev_q0 = tcp;
4390                         tcp->tcp_eager_next_drop_q0 = tcp;
4391                         tcp->tcp_eager_prev_drop_q0 = tcp;
4392                         tcp->tcp_second_ctimer_threshold =
4393                             tcps->tcps_ip_abort_linterval;
4394                 }
4395         }
4396 
4397         /*
4398          * We need to make sure that the conn_recv is set to a non-null
4399          * value before we insert the conn into the classifier table.
4400          * This is to avoid a race with an incoming packet which does an
4401          * ipcl_classify().
4402          * We initially set it to tcp_input_listener_unbound to try to
4403          * pick a good squeue for the listener when the first SYN arrives.
4404          * tcp_input_listener_unbound sets it to tcp_input_listener on that
4405          * first SYN.
4406          */
4407         connp->conn_recv = tcp_input_listener_unbound;
4408 
4409         /* Insert the listener in the classifier table */
4410         error = ip_laddr_fanout_insert(connp);
4411         if (error != 0) {
4412                 /* Undo the bind - release the port number */
4413                 oldstate = tcp->tcp_state;
4414                 tcp->tcp_state = TCPS_IDLE;
4415                 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
4416                     connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
4417                     int32_t, oldstate);
4418                 connp->conn_bound_addr_v6 = ipv6_all_zeros;
4419 
4420                 connp->conn_laddr_v6 = ipv6_all_zeros;
4421                 connp->conn_saddr_v6 = ipv6_all_zeros;
4422                 connp->conn_ports = 0;
4423 
4424                 if (connp->conn_anon_port) {
4425                         zone_t          *zone;
4426 
4427                         zone = crgetzone(cr);
4428                         connp->conn_anon_port = B_FALSE;
4429                         (void) tsol_mlp_anon(zone, connp->conn_mlp_type,
4430                             connp->conn_proto, connp->conn_lport, B_FALSE);
4431                 }
4432                 connp->conn_mlp_type = mlptSingle;
4433 
4434                 tcp_bind_hash_remove(tcp);
4435                 return (error);
4436         } else {
4437                 /*
4438                  * If there is a connection limit, allocate and initialize
4439                  * the counter struct.  Note that since listen can be called
4440                  * multiple times, the struct may have been allready allocated.
4441                  */
4442                 if (!list_is_empty(&tcps->tcps_listener_conf) &&
4443                     tcp->tcp_listen_cnt == NULL) {
4444                         tcp_listen_cnt_t *tlc;
4445                         uint32_t ratio;
4446 
4447                         ratio = tcp_find_listener_conf(tcps,
4448                             ntohs(connp->conn_lport));
4449                         if (ratio != 0) {
4450                                 uint32_t mem_ratio, tot_buf;
4451 
4452                                 tlc = kmem_alloc(sizeof (tcp_listen_cnt_t),
4453                                     KM_SLEEP);
4454                                 /*
4455                                  * Calculate the connection limit based on
4456                                  * the configured ratio and maxusers.  Maxusers
4457                                  * are calculated based on memory size,
4458                                  * ~ 1 user per MB.  Note that the conn_rcvbuf
4459                                  * and conn_sndbuf may change after a
4460                                  * connection is accepted.  So what we have
4461                                  * is only an approximation.
4462                                  */
4463                                 if ((tot_buf = connp->conn_rcvbuf +
4464                                     connp->conn_sndbuf) < MB) {
4465                                         mem_ratio = MB / tot_buf;
4466                                         tlc->tlc_max = maxusers / ratio *
4467                                             mem_ratio;
4468                                 } else {
4469                                         mem_ratio = tot_buf / MB;
4470                                         tlc->tlc_max = maxusers / ratio /
4471                                             mem_ratio;
4472                                 }
4473                                 /* At least we should allow two connections! */
4474                                 if (tlc->tlc_max <= tcp_min_conn_listener)
4475                                         tlc->tlc_max = tcp_min_conn_listener;
4476                                 tlc->tlc_cnt = 1;
4477                                 tlc->tlc_drop = 0;
4478                                 tcp->tcp_listen_cnt = tlc;
4479                         }
4480                 }
4481         }
4482         return (error);
4483 }