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