sys/netinet/tcp_subr.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)tcp_subr.c  8.2 (Berkeley) 5/24/95
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include "opt_compat.h"
  38 #include "opt_inet.h"
  39 #include "opt_inet6.h"
  40 #include "opt_ipsec.h"
  41 #include "opt_tcpdebug.h"
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/callout.h>
  46 #include <sys/eventhandler.h>
  47 #ifdef TCP_HHOOK
  48 #include <sys/hhook.h>
  49 #endif
  50 #include <sys/kernel.h>
  51 #ifdef TCP_HHOOK
  52 #include <sys/khelp.h>
  53 #endif
  54 #include <sys/sysctl.h>
  55 #include <sys/jail.h>
  56 #include <sys/malloc.h>
  57 #include <sys/refcount.h>
  58 #include <sys/mbuf.h>
  59 #ifdef INET6
  60 #include <sys/domain.h>
  61 #endif
  62 #include <sys/priv.h>
  63 #include <sys/proc.h>
  64 #include <sys/sdt.h>
  65 #include <sys/socket.h>
  66 #include <sys/socketvar.h>
  67 #include <sys/protosw.h>
  68 #include <sys/random.h>
  69
  70 #include <vm/uma.h>
  71
  72 #include <net/route.h>
  73 #include <net/if.h>
  74 #include <net/if_var.h>
  75 #include <net/vnet.h>
  76
  77 #include <netinet/in.h>
  78 #include <netinet/in_fib.h>
  79 #include <netinet/in_kdtrace.h>
  80 #include <netinet/in_pcb.h>
  81 #include <netinet/in_systm.h>
  82 #include <netinet/in_var.h>
  83 #include <netinet/ip.h>
  84 #include <netinet/ip_icmp.h>
  85 #include <netinet/ip_var.h>
  86 #ifdef INET6
  87 #include <netinet/icmp6.h>
  88 #include <netinet/ip6.h>
  89 #include <netinet6/in6_fib.h>
  90 #include <netinet6/in6_pcb.h>
  91 #include <netinet6/ip6_var.h>
  92 #include <netinet6/scope6_var.h>
  93 #include <netinet6/nd6.h>
  94 #endif
  95
  96 #include <netinet/tcp.h>
  97 #include <netinet/tcp_fsm.h>
  98 #include <netinet/tcp_seq.h>
  99 #include <netinet/tcp_timer.h>
 100 #include <netinet/tcp_var.h>
 101 #include <netinet/tcp_log_buf.h>
 102 #include <netinet/tcp_syncache.h>
 103 #include <netinet/cc/cc.h>
 104 #ifdef INET6
 105 #include <netinet6/tcp6_var.h>
 106 #endif
 107 #include <netinet/tcpip.h>
 108 #include <netinet/tcp_fastopen.h>
 109 #ifdef TCPPCAP
 110 #include <netinet/tcp_pcap.h>
 111 #endif
 112 #ifdef TCPDEBUG
 113 #include <netinet/tcp_debug.h>
 114 #endif
 115 #ifdef INET6
 116 #include <netinet6/ip6protosw.h>
 117 #endif
 118 #ifdef TCP_OFFLOAD
 119 #include <netinet/tcp_offload.h>
 120 #endif
 121
 122 #include <netipsec/ipsec_support.h>
 123
 124 #include <machine/in_cksum.h>
 125 #include <sys/md5.h>
 126
 127 #include <security/mac/mac_framework.h>
 128
 129 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
 130 #ifdef INET6
 131 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
 132 #endif
 133
 134 struct rwlock tcp_function_lock;
 135
 136 static int
 137 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
 138 {
 139         int error, new;
 140
 141         new = V_tcp_mssdflt;
 142         error = sysctl_handle_int(oidp, &new, 0, req);
 143         if (error == 0 && req->newptr) {
 144                 if (new < TCP_MINMSS)
 145                         error = EINVAL;
 146                 else
 147                         V_tcp_mssdflt = new;
 148         }
 149         return (error);
 150 }
 151
 152 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
 153     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
 154     &sysctl_net_inet_tcp_mss_check, "I",
 155     "Default TCP Maximum Segment Size");
 156
 157 #ifdef INET6
 158 static int
 159 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
 160 {
 161         int error, new;
 162
 163         new = V_tcp_v6mssdflt;
 164         error = sysctl_handle_int(oidp, &new, 0, req);
 165         if (error == 0 && req->newptr) {
 166                 if (new < TCP_MINMSS)
 167                         error = EINVAL;
 168                 else
 169                         V_tcp_v6mssdflt = new;
 170         }
 171         return (error);
 172 }
 173
 174 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
 175     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
 176     &sysctl_net_inet_tcp_mss_v6_check, "I",
 177    "Default TCP Maximum Segment Size for IPv6");
 178 #endif /* INET6 */
 179
 180 /*
 181  * Minimum MSS we accept and use. This prevents DoS attacks where
 182  * we are forced to a ridiculous low MSS like 20 and send hundreds
 183  * of packets instead of one. The effect scales with the available
 184  * bandwidth and quickly saturates the CPU and network interface
 185  * with packet generation and sending. Set to zero to disable MINMSS
 186  * checking. This setting prevents us from sending too small packets.
 187  */
 188 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
 189 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
 190      &VNET_NAME(tcp_minmss), 0,
 191     "Minimum TCP Maximum Segment Size");
 192
 193 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
 194 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
 195     &VNET_NAME(tcp_do_rfc1323), 0,
 196     "Enable rfc1323 (high performance TCP) extensions");
 197
 198 static int      tcp_log_debug = 0;
 199 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
 200     &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
 201
 202 static int      tcp_tcbhashsize;
 203 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
 204     &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
 205
 206 static int      do_tcpdrain = 1;
 207 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
 208     "Enable tcp_drain routine for extra help when low on mbufs");
 209
 210 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
 211     &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
 212
 213 static VNET_DEFINE(int, icmp_may_rst) = 1;
 214 #define V_icmp_may_rst                  VNET(icmp_may_rst)
 215 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
 216     &VNET_NAME(icmp_may_rst), 0,
 217     "Certain ICMP unreachable messages may abort connections in SYN_SENT");
 218
 219 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0;
 220 #define V_tcp_isn_reseed_interval       VNET(tcp_isn_reseed_interval)
 221 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
 222     &VNET_NAME(tcp_isn_reseed_interval), 0,
 223     "Seconds between reseeding of ISN secret");
 224
 225 static int      tcp_soreceive_stream;
 226 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
 227     &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
 228
 229 VNET_DEFINE(uma_zone_t, sack_hole_zone);
 230 #define V_sack_hole_zone                VNET(sack_hole_zone)
 231
 232 #ifdef TCP_HHOOK
 233 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
 234 #endif
 235
 236 static struct inpcb *tcp_notify(struct inpcb *, int);
 237 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
 238 static void tcp_mtudisc(struct inpcb *, int);
 239 static char *   tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
 240                     void *ip4hdr, const void *ip6hdr);
 241
 242
 243 static struct tcp_function_block tcp_def_funcblk = {
 244         "default",
 245         tcp_output,
 246         tcp_do_segment,
 247         tcp_default_ctloutput,
 248         NULL,
 249         NULL,
 250         NULL,
 251         NULL,
 252         NULL,
 253         NULL,
 254         0,
 255         0
 256 };
 257
 258 int t_functions_inited = 0;
 259 struct tcp_funchead t_functions;
 260 static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
 261
 262 static void
 263 init_tcp_functions(void)
 264 {
 265         if (t_functions_inited == 0) {
 266                 TAILQ_INIT(&t_functions);
 267                 rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
 268                 t_functions_inited = 1;
 269         }
 270 }
 271
 272 static struct tcp_function_block *
 273 find_tcp_functions_locked(struct tcp_function_set *fs)
 274 {
 275         struct tcp_function *f;
 276         struct tcp_function_block *blk=NULL;
 277
 278         TAILQ_FOREACH(f, &t_functions, tf_next) {
 279                 if (strcmp(f->tf_name, fs->function_set_name) == 0) {
 280                         blk = f->tf_fb;
 281                         break;
 282                 }
 283         }
 284         return(blk);
 285 }
 286
 287 static struct tcp_function_block *
 288 find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
 289 {
 290         struct tcp_function_block *rblk=NULL;
 291         struct tcp_function *f;
 292
 293         TAILQ_FOREACH(f, &t_functions, tf_next) {
 294                 if (f->tf_fb == blk) {
 295                         rblk = blk;
 296                         if (s) {
 297                                 *s = f;
 298                         }
 299                         break;
 300                 }
 301         }
 302         return (rblk);
 303 }
 304
 305 struct tcp_function_block *
 306 find_and_ref_tcp_functions(struct tcp_function_set *fs)
 307 {
 308         struct tcp_function_block *blk;
 309
 310         rw_rlock(&tcp_function_lock);
 311         blk = find_tcp_functions_locked(fs);
 312         if (blk)
 313                 refcount_acquire(&blk->tfb_refcnt);
 314         rw_runlock(&tcp_function_lock);
 315         return(blk);
 316 }
 317
 318 struct tcp_function_block *
 319 find_and_ref_tcp_fb(struct tcp_function_block *blk)
 320 {
 321         struct tcp_function_block *rblk;
 322
 323         rw_rlock(&tcp_function_lock);
 324         rblk = find_tcp_fb_locked(blk, NULL);
 325         if (rblk)
 326                 refcount_acquire(&rblk->tfb_refcnt);
 327         rw_runlock(&tcp_function_lock);
 328         return(rblk);
 329 }
 330
 331
 332 static int
 333 sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
 334 {
 335         int error=ENOENT;
 336         struct tcp_function_set fs;
 337         struct tcp_function_block *blk;
 338
 339         memset(&fs, 0, sizeof(fs));
 340         rw_rlock(&tcp_function_lock);
 341         blk = find_tcp_fb_locked(tcp_func_set_ptr, NULL);
 342         if (blk) {
 343                 /* Found him */
 344                 strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
 345                 fs.pcbcnt = blk->tfb_refcnt;
 346         }
 347         rw_runlock(&tcp_function_lock);
 348         error = sysctl_handle_string(oidp, fs.function_set_name,
 349                                      sizeof(fs.function_set_name), req);
 350
 351         /* Check for error or no change */
 352         if (error != 0 || req->newptr == NULL)
 353                 return(error);
 354
 355         rw_wlock(&tcp_function_lock);
 356         blk = find_tcp_functions_locked(&fs);
 357         if ((blk == NULL) ||
 358             (blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
 359                 error = ENOENT;
 360                 goto done;
 361         }
 362         tcp_func_set_ptr = blk;
 363 done:
 364         rw_wunlock(&tcp_function_lock);
 365         return (error);
 366 }
 367
 368 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
 369             CTLTYPE_STRING | CTLFLAG_RW,
 370             NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
 371             "Set/get the default TCP functions");
 372
 373 static int
 374 sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
 375 {
 376         int error, cnt, linesz;
 377         struct tcp_function *f;
 378         char *buffer, *cp;
 379         size_t bufsz, outsz;
 380         bool alias;
 381
 382         cnt = 0;
 383         rw_rlock(&tcp_function_lock);
 384         TAILQ_FOREACH(f, &t_functions, tf_next) {
 385                 cnt++;
 386         }
 387         rw_runlock(&tcp_function_lock);
 388
 389         bufsz = (cnt+2) * ((TCP_FUNCTION_NAME_LEN_MAX * 2) + 13) + 1;
 390         buffer = malloc(bufsz, M_TEMP, M_WAITOK);
 391
 392         error = 0;
 393         cp = buffer;
 394
 395         linesz = snprintf(cp, bufsz, "\n%-32s%c %-32s %s\n", "Stack", 'D',
 396             "Alias", "PCB count");
 397         cp += linesz;
 398         bufsz -= linesz;
 399         outsz = linesz;
 400
 401         rw_rlock(&tcp_function_lock);
 402         TAILQ_FOREACH(f, &t_functions, tf_next) {
 403                 alias = (f->tf_name != f->tf_fb->tfb_tcp_block_name);
 404                 linesz = snprintf(cp, bufsz, "%-32s%c %-32s %u\n",
 405                     f->tf_fb->tfb_tcp_block_name,
 406                     (f->tf_fb == tcp_func_set_ptr) ? '*' : ' ',
 407                     alias ? f->tf_name : "-",
 408                     f->tf_fb->tfb_refcnt);
 409                 if (linesz >= bufsz) {
 410                         error = EOVERFLOW;
 411                         break;
 412                 }
 413                 cp += linesz;
 414                 bufsz -= linesz;
 415                 outsz += linesz;
 416         }
 417         rw_runlock(&tcp_function_lock);
 418         if (error == 0)
 419                 error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
 420         free(buffer, M_TEMP);
 421         return (error);
 422 }
 423
 424 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
 425             CTLTYPE_STRING|CTLFLAG_RD,
 426             NULL, 0, sysctl_net_inet_list_available, "A",
 427             "list available TCP Function sets");
 428
 429 /*
 430  * Exports one (struct tcp_function_id) for each non-alias.
 431  */
 432 static int
 433 sysctl_net_inet_list_func_ids(SYSCTL_HANDLER_ARGS)
 434 {
 435         int error, cnt;
 436         struct tcp_function *f;
 437         struct tcp_function_id tfi;
 438
 439         /*
 440          * We don't allow writes.
 441          */
 442         if (req->newptr != NULL)
 443                 return (EINVAL);
 444
 445         /*
 446          * Wire the old buffer so we can directly copy the functions to
 447          * user space without dropping the lock.
 448          */
 449         if (req->oldptr != NULL) {
 450                 error = sysctl_wire_old_buffer(req, 0);
 451                 if (error)
 452                         return (error);
 453         }
 454
 455         /*
 456          * Walk the list, comparing the name of the function entry and
 457          * function block to determine which is an alias.
 458          * If exporting the list, copy out matching entries. Otherwise,
 459          * just record the total length.
 460          */
 461         cnt = 0;
 462         rw_rlock(&tcp_function_lock);
 463         TAILQ_FOREACH(f, &t_functions, tf_next) {
 464                 if (strncmp(f->tf_name, f->tf_fb->tfb_tcp_block_name,
 465                     TCP_FUNCTION_NAME_LEN_MAX))
 466                         continue;
 467                 if (req->oldptr != NULL) {
 468                         tfi.tfi_id = f->tf_fb->tfb_id;
 469                         (void)strncpy(tfi.tfi_name, f->tf_name,
 470                             TCP_FUNCTION_NAME_LEN_MAX);
 471                         tfi.tfi_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
 472                         error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
 473                         /*
 474                          * Don't stop on error, as that is the
 475                          * mechanism we use to accumulate length
 476                          * information if the buffer was too short.
 477                          */
 478                 } else
 479                         cnt++;
 480         }
 481         rw_runlock(&tcp_function_lock);
 482         if (req->oldptr == NULL)
 483                 error = SYSCTL_OUT(req, NULL,
 484                     (cnt + 1) * sizeof(struct tcp_function_id));
 485
 486         return (error);
 487 }
 488
 489 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, function_ids,
 490             CTLTYPE_OPAQUE | CTLFLAG_SKIP | CTLFLAG_RD | CTLFLAG_MPSAFE,
 491             NULL, 0, sysctl_net_inet_list_func_ids, "S,tcp_function_id",
 492             "List TCP function block name-to-ID mappings");
 493
 494 /*
 495  * Target size of TCP PCB hash tables. Must be a power of two.
 496  *
 497  * Note that this can be overridden by the kernel environment
 498  * variable net.inet.tcp.tcbhashsize
 499  */
 500 #ifndef TCBHASHSIZE
 501 #define TCBHASHSIZE     0
 502 #endif
 503
 504 /*
 505  * XXX
 506  * Callouts should be moved into struct tcp directly.  They are currently
 507  * separate because the tcpcb structure is exported to userland for sysctl
 508  * parsing purposes, which do not know about callouts.
 509  */
 510 struct tcpcb_mem {
 511         struct  tcpcb           tcb;
 512         struct  tcp_timer       tt;
 513         struct  cc_var          ccv;
 514 #ifdef TCP_HHOOK
 515         struct  osd             osd;
 516 #endif
 517 };
 518
 519 static VNET_DEFINE(uma_zone_t, tcpcb_zone);
 520 #define V_tcpcb_zone                    VNET(tcpcb_zone)
 521
 522 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
 523 MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
 524
 525 static struct mtx isn_mtx;
 526
 527 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
 528 #define ISN_LOCK()      mtx_lock(&isn_mtx)
 529 #define ISN_UNLOCK()    mtx_unlock(&isn_mtx)
 530
 531 /*
 532  * TCP initialization.
 533  */
 534 static void
 535 tcp_zone_change(void *tag)
 536 {
 537
 538         uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
 539         uma_zone_set_max(V_tcpcb_zone, maxsockets);
 540         tcp_tw_zone_change();
 541 }
 542
 543 static int
 544 tcp_inpcb_init(void *mem, int size, int flags)
 545 {
 546         struct inpcb *inp = mem;
 547
 548         INP_LOCK_INIT(inp, "inp", "tcpinp");
 549         return (0);
 550 }
 551
 552 /*
 553  * Take a value and get the next power of 2 that doesn't overflow.
 554  * Used to size the tcp_inpcb hash buckets.
 555  */
 556 static int
 557 maketcp_hashsize(int size)
 558 {
 559         int hashsize;
 560
 561         /*
 562          * auto tune.
 563          * get the next power of 2 higher than maxsockets.
 564          */
 565         hashsize = 1 << fls(size);
 566         /* catch overflow, and just go one power of 2 smaller */
 567         if (hashsize < size) {
 568                 hashsize = 1 << (fls(size) - 1);
 569         }
 570         return (hashsize);
 571 }
 572
 573 static volatile int next_tcp_stack_id = 1;
 574
 575 /*
 576  * Register a TCP function block with the name provided in the names
 577  * array.  (Note that this function does NOT automatically register
 578  * blk->tfb_tcp_block_name as a stack name.  Therefore, you should
 579  * explicitly include blk->tfb_tcp_block_name in the list of names if
 580  * you wish to register the stack with that name.)
 581  *
 582  * Either all name registrations will succeed or all will fail.  If
 583  * a name registration fails, the function will update the num_names
 584  * argument to point to the array index of the name that encountered
 585  * the failure.
 586  *
 587  * Returns 0 on success, or an error code on failure.
 588  */
 589 int
 590 register_tcp_functions_as_names(struct tcp_function_block *blk, int wait,
 591     const char *names[], int *num_names)
 592 {
 593         struct tcp_function *n;
 594         struct tcp_function_set fs;
 595         int error, i;
 596
 597         KASSERT(names != NULL && *num_names > 0,
 598             ("%s: Called with 0-length name list", __func__));
 599         KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
 600
 601         if (t_functions_inited == 0) {
 602                 init_tcp_functions();
 603         }
 604         if ((blk->tfb_tcp_output == NULL) ||
 605             (blk->tfb_tcp_do_segment == NULL) ||
 606             (blk->tfb_tcp_ctloutput == NULL) ||
 607             (strlen(blk->tfb_tcp_block_name) == 0)) {
 608                 /*
 609                  * These functions are required and you
 610                  * need a name.
 611                  */
 612                 *num_names = 0;
 613                 return (EINVAL);
 614         }
 615         if (blk->tfb_tcp_timer_stop_all ||
 616             blk->tfb_tcp_timer_activate ||
 617             blk->tfb_tcp_timer_active ||
 618             blk->tfb_tcp_timer_stop) {
 619                 /*
 620                  * If you define one timer function you
 621                  * must have them all.
 622                  */
 623                 if ((blk->tfb_tcp_timer_stop_all == NULL) ||
 624                     (blk->tfb_tcp_timer_activate == NULL) ||
 625                     (blk->tfb_tcp_timer_active == NULL) ||
 626                     (blk->tfb_tcp_timer_stop == NULL)) {
 627                         *num_names = 0;
 628                         return (EINVAL);
 629                 }
 630         }
 631
 632         refcount_init(&blk->tfb_refcnt, 0);
 633         blk->tfb_flags = 0;
 634         blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
 635         for (i = 0; i < *num_names; i++) {
 636                 n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
 637                 if (n == NULL) {
 638                         error = ENOMEM;
 639                         goto cleanup;
 640                 }
 641                 n->tf_fb = blk;
 642
 643                 (void)strncpy(fs.function_set_name, names[i],
 644                     TCP_FUNCTION_NAME_LEN_MAX);
 645                 fs.function_set_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
 646                 rw_wlock(&tcp_function_lock);
 647                 if (find_tcp_functions_locked(&fs) != NULL) {
 648                         /* Duplicate name space not allowed */
 649                         rw_wunlock(&tcp_function_lock);
 650                         free(n, M_TCPFUNCTIONS);
 651                         error = EALREADY;
 652                         goto cleanup;
 653                 }
 654                 (void)strncpy(n->tf_name, names[i], TCP_FUNCTION_NAME_LEN_MAX);
 655                 n->tf_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
 656                 TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
 657                 rw_wunlock(&tcp_function_lock);
 658         }
 659         return(0);
 660
 661 cleanup:
 662         /*
 663          * Deregister the names we just added. Because registration failed
 664          * for names[i], we don't need to deregister that name.
 665          */
 666         *num_names = i;
 667         rw_wlock(&tcp_function_lock);
 668         while (--i >= 0) {
 669                 TAILQ_FOREACH(n, &t_functions, tf_next) {
 670                         if (!strncmp(n->tf_name, names[i],
 671                             TCP_FUNCTION_NAME_LEN_MAX)) {
 672                                 TAILQ_REMOVE(&t_functions, n, tf_next);
 673                                 n->tf_fb = NULL;
 674                                 free(n, M_TCPFUNCTIONS);
 675                                 break;
 676                         }
 677                 }
 678         }
 679         rw_wunlock(&tcp_function_lock);
 680         return (error);
 681 }
 682
 683 /*
 684  * Register a TCP function block using the name provided in the name
 685  * argument.
 686  *
 687  * Returns 0 on success, or an error code on failure.
 688  */
 689 int
 690 register_tcp_functions_as_name(struct tcp_function_block *blk, const char *name,
 691     int wait)
 692 {
 693         const char *name_list[1];
 694         int num_names, rv;
 695
 696         num_names = 1;
 697         if (name != NULL)
 698                 name_list[0] = name;
 699         else
 700                 name_list[0] = blk->tfb_tcp_block_name;
 701         rv = register_tcp_functions_as_names(blk, wait, name_list, &num_names);
 702         return (rv);
 703 }
 704
 705 /*
 706  * Register a TCP function block using the name defined in
 707  * blk->tfb_tcp_block_name.
 708  *
 709  * Returns 0 on success, or an error code on failure.
 710  */
 711 int
 712 register_tcp_functions(struct tcp_function_block *blk, int wait)
 713 {
 714
 715         return (register_tcp_functions_as_name(blk, NULL, wait));
 716 }
 717
 718 int
 719 deregister_tcp_functions(struct tcp_function_block *blk)
 720 {
 721         struct tcp_function *f;
 722         int error=ENOENT;
 723
 724         if (strcmp(blk->tfb_tcp_block_name, "default") == 0) {
 725                 /* You can't un-register the default */
 726                 return (EPERM);
 727         }
 728         rw_wlock(&tcp_function_lock);
 729         if (blk == tcp_func_set_ptr) {
 730                 /* You can't free the current default */
 731                 rw_wunlock(&tcp_function_lock);
 732                 return (EBUSY);
 733         }
 734         if (blk->tfb_refcnt) {
 735                 /* Still tcb attached, mark it. */
 736                 blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
 737                 rw_wunlock(&tcp_function_lock);
 738                 return (EBUSY);
 739         }
 740         while (find_tcp_fb_locked(blk, &f) != NULL) {
 741                 /* Found */
 742                 TAILQ_REMOVE(&t_functions, f, tf_next);
 743                 f->tf_fb = NULL;
 744                 free(f, M_TCPFUNCTIONS);
 745                 error = 0;
 746         }
 747         rw_wunlock(&tcp_function_lock);
 748         return (error);
 749 }
 750
 751 void
 752 tcp_init(void)
 753 {
 754         const char *tcbhash_tuneable;
 755         int hashsize;
 756
 757         tcbhash_tuneable = "net.inet.tcp.tcbhashsize";
 758
 759 #ifdef TCP_HHOOK
 760         if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
 761             &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
 762                 printf("%s: WARNING: unable to register helper hook\n", __func__);
 763         if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
 764             &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
 765                 printf("%s: WARNING: unable to register helper hook\n", __func__);
 766 #endif
 767         hashsize = TCBHASHSIZE;
 768         TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize);
 769         if (hashsize == 0) {
 770                 /*
 771                  * Auto tune the hash size based on maxsockets.
 772                  * A perfect hash would have a 1:1 mapping
 773                  * (hashsize = maxsockets) however it's been
 774                  * suggested that O(2) average is better.
 775                  */
 776                 hashsize = maketcp_hashsize(maxsockets / 4);
 777                 /*
 778                  * Our historical default is 512,
 779                  * do not autotune lower than this.
 780                  */
 781                 if (hashsize < 512)
 782                         hashsize = 512;
 783                 if (bootverbose && IS_DEFAULT_VNET(curvnet))
 784                         printf("%s: %s auto tuned to %d\n", __func__,
 785                             tcbhash_tuneable, hashsize);
 786         }
 787         /*
 788          * We require a hashsize to be a power of two.
 789          * Previously if it was not a power of two we would just reset it
 790          * back to 512, which could be a nasty surprise if you did not notice
 791          * the error message.
 792          * Instead what we do is clip it to the closest power of two lower
 793          * than the specified hash value.
 794          */
 795         if (!powerof2(hashsize)) {
 796                 int oldhashsize = hashsize;
 797
 798                 hashsize = maketcp_hashsize(hashsize);
 799                 /* prevent absurdly low value */
 800                 if (hashsize < 16)
 801                         hashsize = 16;
 802                 printf("%s: WARNING: TCB hash size not a power of 2, "
 803                     "clipped from %d to %d.\n", __func__, oldhashsize,
 804                     hashsize);
 805         }
 806         in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
 807             "tcp_inpcb", tcp_inpcb_init, IPI_HASHFIELDS_4TUPLE);
 808
 809         /*
 810          * These have to be type stable for the benefit of the timers.
 811          */
 812         V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
 813             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 814         uma_zone_set_max(V_tcpcb_zone, maxsockets);
 815         uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached");
 816
 817         tcp_tw_init();
 818         syncache_init();
 819         tcp_hc_init();
 820
 821         TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
 822         V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
 823             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 824
 825         tcp_fastopen_init();
 826
 827         /* Skip initialization of globals for non-default instances. */
 828         if (!IS_DEFAULT_VNET(curvnet))
 829                 return;
 830
 831         tcp_reass_global_init();
 832
 833         /* XXX virtualize those bellow? */
 834         tcp_delacktime = TCPTV_DELACK;
 835         tcp_keepinit = TCPTV_KEEP_INIT;
 836         tcp_keepidle = TCPTV_KEEP_IDLE;
 837         tcp_keepintvl = TCPTV_KEEPINTVL;
 838         tcp_maxpersistidle = TCPTV_KEEP_IDLE;
 839         tcp_msl = TCPTV_MSL;
 840         tcp_rexmit_min = TCPTV_MIN;
 841         if (tcp_rexmit_min < 1)
 842                 tcp_rexmit_min = 1;
 843         tcp_persmin = TCPTV_PERSMIN;
 844         tcp_persmax = TCPTV_PERSMAX;
 845         tcp_rexmit_slop = TCPTV_CPU_VAR;
 846         tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
 847         tcp_tcbhashsize = hashsize;
 848         /* Setup the tcp function block list */
 849         init_tcp_functions();
 850         register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
 851 #ifdef TCP_BLACKBOX
 852         /* Initialize the TCP logging data. */
 853         tcp_log_init();
 854 #endif
 855
 856         if (tcp_soreceive_stream) {
 857 #ifdef INET
 858                 tcp_usrreqs.pru_soreceive = soreceive_stream;
 859 #endif
 860 #ifdef INET6
 861                 tcp6_usrreqs.pru_soreceive = soreceive_stream;
 862 #endif /* INET6 */
 863         }
 864
 865 #ifdef INET6
 866 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
 867 #else /* INET6 */
 868 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
 869 #endif /* INET6 */
 870         if (max_protohdr < TCP_MINPROTOHDR)
 871                 max_protohdr = TCP_MINPROTOHDR;
 872         if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
 873                 panic("tcp_init");
 874 #undef TCP_MINPROTOHDR
 875
 876         ISN_LOCK_INIT();
 877         EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
 878                 SHUTDOWN_PRI_DEFAULT);
 879         EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
 880                 EVENTHANDLER_PRI_ANY);
 881 #ifdef TCPPCAP
 882         tcp_pcap_init();
 883 #endif
 884 }
 885
 886 #ifdef VIMAGE
 887 static void
 888 tcp_destroy(void *unused __unused)
 889 {
 890         int n;
 891 #ifdef TCP_HHOOK
 892         int error;
 893 #endif
 894
 895         /*
 896          * All our processes are gone, all our sockets should be cleaned
 897          * up, which means, we should be past the tcp_discardcb() calls.
 898          * Sleep to let all tcpcb timers really disappear and cleanup.
 899          */
 900         for (;;) {
 901                 INP_LIST_RLOCK(&V_tcbinfo);
 902                 n = V_tcbinfo.ipi_count;
 903                 INP_LIST_RUNLOCK(&V_tcbinfo);
 904                 if (n == 0)
 905                         break;
 906                 pause("tcpdes", hz / 10);
 907         }
 908         tcp_hc_destroy();
 909         syncache_destroy();
 910         tcp_tw_destroy();
 911         in_pcbinfo_destroy(&V_tcbinfo);
 912         /* tcp_discardcb() clears the sack_holes up. */
 913         uma_zdestroy(V_sack_hole_zone);
 914         uma_zdestroy(V_tcpcb_zone);
 915
 916         /*
 917          * Cannot free the zone until all tcpcbs are released as we attach
 918          * the allocations to them.
 919          */
 920         tcp_fastopen_destroy();
 921
 922 #ifdef TCP_HHOOK
 923         error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
 924         if (error != 0) {
 925                 printf("%s: WARNING: unable to deregister helper hook "
 926                     "type=%d, id=%d: error %d returned\n", __func__,
 927                     HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
 928         }
 929         error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
 930         if (error != 0) {
 931                 printf("%s: WARNING: unable to deregister helper hook "
 932                     "type=%d, id=%d: error %d returned\n", __func__,
 933                     HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
 934         }
 935 #endif
 936 }
 937 VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
 938 #endif
 939
 940 void
 941 tcp_fini(void *xtp)
 942 {
 943
 944 }
 945
 946 /*
 947  * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
 948  * tcp_template used to store this data in mbufs, but we now recopy it out
 949  * of the tcpcb each time to conserve mbufs.
 950  */
 951 void
 952 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
 953 {
 954         struct tcphdr *th = (struct tcphdr *)tcp_ptr;
 955
 956         INP_WLOCK_ASSERT(inp);
 957
 958 #ifdef INET6
 959         if ((inp->inp_vflag & INP_IPV6) != 0) {
 960                 struct ip6_hdr *ip6;
 961
 962                 ip6 = (struct ip6_hdr *)ip_ptr;
 963                 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
 964                         (inp->inp_flow & IPV6_FLOWINFO_MASK);
 965                 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
 966                         (IPV6_VERSION & IPV6_VERSION_MASK);
 967                 ip6->ip6_nxt = IPPROTO_TCP;
 968                 ip6->ip6_plen = htons(sizeof(struct tcphdr));
 969                 ip6->ip6_src = inp->in6p_laddr;
 970                 ip6->ip6_dst = inp->in6p_faddr;
 971         }
 972 #endif /* INET6 */
 973 #if defined(INET6) && defined(INET)
 974         else
 975 #endif
 976 #ifdef INET
 977         {
 978                 struct ip *ip;
 979
 980                 ip = (struct ip *)ip_ptr;
 981                 ip->ip_v = IPVERSION;
 982                 ip->ip_hl = 5;
 983                 ip->ip_tos = inp->inp_ip_tos;
 984                 ip->ip_len = 0;
 985                 ip->ip_id = 0;
 986                 ip->ip_off = 0;
 987                 ip->ip_ttl = inp->inp_ip_ttl;
 988                 ip->ip_sum = 0;
 989                 ip->ip_p = IPPROTO_TCP;
 990                 ip->ip_src = inp->inp_laddr;
 991                 ip->ip_dst = inp->inp_faddr;
 992         }
 993 #endif /* INET */
 994         th->th_sport = inp->inp_lport;
 995         th->th_dport = inp->inp_fport;
 996         th->th_seq = 0;
 997         th->th_ack = 0;
 998         th->th_x2 = 0;
 999         th->th_off = 5;
1000         th->th_flags = 0;
1001         th->th_win = 0;
1002         th->th_urp = 0;
1003         th->th_sum = 0;         /* in_pseudo() is called later for ipv4 */
1004 }
1005
1006 /*
1007  * Create template to be used to send tcp packets on a connection.
1008  * Allocates an mbuf and fills in a skeletal tcp/ip header.  The only
1009  * use for this function is in keepalives, which use tcp_respond.
1010  */
1011 struct tcptemp *
1012 tcpip_maketemplate(struct inpcb *inp)
1013 {
1014         struct tcptemp *t;
1015
1016         t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
1017         if (t == NULL)
1018                 return (NULL);
1019         tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
1020         return (t);
1021 }
1022
1023 /*
1024  * Send a single message to the TCP at address specified by
1025  * the given TCP/IP header.  If m == NULL, then we make a copy
1026  * of the tcpiphdr at th and send directly to the addressed host.
1027  * This is used to force keep alive messages out using the TCP
1028  * template for a connection.  If flags are given then we send
1029  * a message back to the TCP which originated the segment th,
1030  * and discard the mbuf containing it and any other attached mbufs.
1031  *
1032  * In any case the ack and sequence number of the transmitted
1033  * segment are as specified by the parameters.
1034  *
1035  * NOTE: If m != NULL, then th must point to *inside* the mbuf.
1036  */
1037 void
1038 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
1039     tcp_seq ack, tcp_seq seq, int flags)
1040 {
1041         struct tcpopt to;
1042         struct inpcb *inp;
1043         struct ip *ip;
1044         struct mbuf *optm;
1045         struct tcphdr *nth;
1046         u_char *optp;
1047 #ifdef INET6
1048         struct ip6_hdr *ip6;
1049         int isipv6;
1050 #endif /* INET6 */
1051         int optlen, tlen, win;
1052         bool incl_opts;
1053
1054         KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
1055
1056 #ifdef INET6
1057         isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
1058         ip6 = ipgen;
1059 #endif /* INET6 */
1060         ip = ipgen;
1061
1062         if (tp != NULL) {
1063                 inp = tp->t_inpcb;
1064                 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
1065                 INP_WLOCK_ASSERT(inp);
1066         } else
1067                 inp = NULL;
1068
1069         incl_opts = false;
1070         win = 0;
1071         if (tp != NULL) {
1072                 if (!(flags & TH_RST)) {
1073                         win = sbspace(&inp->inp_socket->so_rcv);
1074                         if (win > TCP_MAXWIN << tp->rcv_scale)
1075                                 win = TCP_MAXWIN << tp->rcv_scale;
1076                 }
1077                 if ((tp->t_flags & TF_NOOPT) == 0)
1078                         incl_opts = true;
1079         }
1080         if (m == NULL) {
1081                 m = m_gethdr(M_NOWAIT, MT_DATA);
1082                 if (m == NULL)
1083                         return;
1084                 m->m_data += max_linkhdr;
1085 #ifdef INET6
1086                 if (isipv6) {
1087                         bcopy((caddr_t)ip6, mtod(m, caddr_t),
1088                               sizeof(struct ip6_hdr));
1089                         ip6 = mtod(m, struct ip6_hdr *);
1090                         nth = (struct tcphdr *)(ip6 + 1);
1091                 } else
1092 #endif /* INET6 */
1093                 {
1094                         bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1095                         ip = mtod(m, struct ip *);
1096                         nth = (struct tcphdr *)(ip + 1);
1097                 }
1098                 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1099                 flags = TH_ACK;
1100         } else if (!M_WRITABLE(m)) {
1101                 struct mbuf *n;
1102
1103                 /* Can't reuse 'm', allocate a new mbuf. */
1104                 n = m_gethdr(M_NOWAIT, MT_DATA);
1105                 if (n == NULL) {
1106                         m_freem(m);
1107                         return;
1108                 }
1109
1110                 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
1111                         m_freem(m);
1112                         m_freem(n);
1113                         return;
1114                 }
1115
1116                 n->m_data += max_linkhdr;
1117                 /* m_len is set later */
1118 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
1119 #ifdef INET6
1120                 if (isipv6) {
1121                         bcopy((caddr_t)ip6, mtod(n, caddr_t),
1122                               sizeof(struct ip6_hdr));
1123                         ip6 = mtod(n, struct ip6_hdr *);
1124                         xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1125                         nth = (struct tcphdr *)(ip6 + 1);
1126                 } else
1127 #endif /* INET6 */
1128                 {
1129                         bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
1130                         ip = mtod(n, struct ip *);
1131                         xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1132                         nth = (struct tcphdr *)(ip + 1);
1133                 }
1134                 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1135                 xchg(nth->th_dport, nth->th_sport, uint16_t);
1136                 th = nth;
1137                 m_freem(m);
1138                 m = n;
1139         } else {
1140                 /*
1141                  *  reuse the mbuf.
1142                  * XXX MRT We inherit the FIB, which is lucky.
1143                  */
1144                 m_freem(m->m_next);
1145                 m->m_next = NULL;
1146                 m->m_data = (caddr_t)ipgen;
1147                 /* m_len is set later */
1148 #ifdef INET6
1149                 if (isipv6) {
1150                         xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1151                         nth = (struct tcphdr *)(ip6 + 1);
1152                 } else
1153 #endif /* INET6 */
1154                 {
1155                         xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1156                         nth = (struct tcphdr *)(ip + 1);
1157                 }
1158                 if (th != nth) {
1159                         /*
1160                          * this is usually a case when an extension header
1161                          * exists between the IPv6 header and the
1162                          * TCP header.
1163                          */
1164                         nth->th_sport = th->th_sport;
1165                         nth->th_dport = th->th_dport;
1166                 }
1167                 xchg(nth->th_dport, nth->th_sport, uint16_t);
1168 #undef xchg
1169         }
1170         tlen = 0;
1171 #ifdef INET6
1172         if (isipv6)
1173                 tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
1174 #endif
1175 #if defined(INET) && defined(INET6)
1176         else
1177 #endif
1178 #ifdef INET
1179                 tlen = sizeof (struct tcpiphdr);
1180 #endif
1181 #ifdef INVARIANTS
1182         m->m_len = 0;
1183         KASSERT(M_TRAILINGSPACE(m) >= tlen,
1184             ("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
1185             m, tlen, (long)M_TRAILINGSPACE(m)));
1186 #endif
1187         m->m_len = tlen;
1188         to.to_flags = 0;
1189         if (incl_opts) {
1190                 /* Make sure we have room. */
1191                 if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
1192                         m->m_next = m_get(M_NOWAIT, MT_DATA);
1193                         if (m->m_next) {
1194                                 optp = mtod(m->m_next, u_char *);
1195                                 optm = m->m_next;
1196                         } else
1197                                 incl_opts = false;
1198                 } else {
1199                         optp = (u_char *) (nth + 1);
1200                         optm = m;
1201                 }
1202         }
1203         if (incl_opts) {
1204                 /* Timestamps. */
1205                 if (tp->t_flags & TF_RCVD_TSTMP) {
1206                         to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
1207                         to.to_tsecr = tp->ts_recent;
1208                         to.to_flags |= TOF_TS;
1209                 }
1210 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1211                 /* TCP-MD5 (RFC2385). */
1212                 if (tp->t_flags & TF_SIGNATURE)
1213                         to.to_flags |= TOF_SIGNATURE;
1214 #endif
1215                 /* Add the options. */
1216                 tlen += optlen = tcp_addoptions(&to, optp);
1217
1218                 /* Update m_len in the correct mbuf. */
1219                 optm->m_len += optlen;
1220         } else
1221                 optlen = 0;
1222 #ifdef INET6
1223         if (isipv6) {
1224                 ip6->ip6_flow = 0;
1225                 ip6->ip6_vfc = IPV6_VERSION;
1226                 ip6->ip6_nxt = IPPROTO_TCP;
1227                 ip6->ip6_plen = htons(tlen - sizeof(*ip6));
1228         }
1229 #endif
1230 #if defined(INET) && defined(INET6)
1231         else
1232 #endif
1233 #ifdef INET
1234         {
1235                 ip->ip_len = htons(tlen);
1236                 ip->ip_ttl = V_ip_defttl;
1237                 if (V_path_mtu_discovery)
1238                         ip->ip_off |= htons(IP_DF);
1239         }
1240 #endif
1241         m->m_pkthdr.len = tlen;
1242         m->m_pkthdr.rcvif = NULL;
1243 #ifdef MAC
1244         if (inp != NULL) {
1245                 /*
1246                  * Packet is associated with a socket, so allow the
1247                  * label of the response to reflect the socket label.
1248                  */
1249                 INP_WLOCK_ASSERT(inp);
1250                 mac_inpcb_create_mbuf(inp, m);
1251         } else {
1252                 /*
1253                  * Packet is not associated with a socket, so possibly
1254                  * update the label in place.
1255                  */
1256                 mac_netinet_tcp_reply(m);
1257         }
1258 #endif
1259         nth->th_seq = htonl(seq);
1260         nth->th_ack = htonl(ack);
1261         nth->th_x2 = 0;
1262         nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
1263         nth->th_flags = flags;
1264         if (tp != NULL)
1265                 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
1266         else
1267                 nth->th_win = htons((u_short)win);
1268         nth->th_urp = 0;
1269
1270 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1271         if (to.to_flags & TOF_SIGNATURE) {
1272                 if (!TCPMD5_ENABLED() ||
1273                     TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
1274                         m_freem(m);
1275                         return;
1276                 }
1277         }
1278 #endif
1279
1280         m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1281 #ifdef INET6
1282         if (isipv6) {
1283                 m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
1284                 nth->th_sum = in6_cksum_pseudo(ip6,
1285                     tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
1286                 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
1287                     NULL, NULL);
1288         }
1289 #endif /* INET6 */
1290 #if defined(INET6) && defined(INET)
1291         else
1292 #endif
1293 #ifdef INET
1294         {
1295                 m->m_pkthdr.csum_flags = CSUM_TCP;
1296                 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1297                     htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
1298         }
1299 #endif /* INET */
1300 #ifdef TCPDEBUG
1301         if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
1302                 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
1303 #endif
1304         TCP_PROBE3(debug__output, tp, th, m);
1305         if (flags & TH_RST)
1306                 TCP_PROBE5(accept__refused, NULL, NULL, m, tp, nth);
1307
1308 #ifdef INET6
1309         if (isipv6) {
1310                 TCP_PROBE5(send, NULL, tp, ip6, tp, nth);
1311                 (void)ip6_output(m, NULL, NULL, 0, NULL, NULL, inp);
1312         }
1313 #endif /* INET6 */
1314 #if defined(INET) && defined(INET6)
1315         else
1316 #endif
1317 #ifdef INET
1318         {
1319                 TCP_PROBE5(send, NULL, tp, ip, tp, nth);
1320                 (void)ip_output(m, NULL, NULL, 0, NULL, inp);
1321         }
1322 #endif
1323 }
1324
1325 /*
1326  * Create a new TCP control block, making an
1327  * empty reassembly queue and hooking it to the argument
1328  * protocol control block.  The `inp' parameter must have
1329  * come from the zone allocator set up in tcp_init().
1330  */
1331 struct tcpcb *
1332 tcp_newtcpcb(struct inpcb *inp)
1333 {
1334         struct tcpcb_mem *tm;
1335         struct tcpcb *tp;
1336 #ifdef INET6
1337         int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1338 #endif /* INET6 */
1339
1340         tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
1341         if (tm == NULL)
1342                 return (NULL);
1343         tp = &tm->tcb;
1344
1345         /* Initialise cc_var struct for this tcpcb. */
1346         tp->ccv = &tm->ccv;
1347         tp->ccv->type = IPPROTO_TCP;
1348         tp->ccv->ccvc.tcp = tp;
1349         rw_rlock(&tcp_function_lock);
1350         tp->t_fb = tcp_func_set_ptr;
1351         refcount_acquire(&tp->t_fb->tfb_refcnt);
1352         rw_runlock(&tcp_function_lock);
1353         /*
1354          * Use the current system default CC algorithm.
1355          */
1356         CC_LIST_RLOCK();
1357         KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
1358         CC_ALGO(tp) = CC_DEFAULT();
1359         CC_LIST_RUNLOCK();
1360
1361         if (CC_ALGO(tp)->cb_init != NULL)
1362                 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
1363                         if (tp->t_fb->tfb_tcp_fb_fini)
1364                                 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1365                         refcount_release(&tp->t_fb->tfb_refcnt);
1366                         uma_zfree(V_tcpcb_zone, tm);
1367                         return (NULL);
1368                 }
1369
1370 #ifdef TCP_HHOOK
1371         tp->osd = &tm->osd;
1372         if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
1373                 if (tp->t_fb->tfb_tcp_fb_fini)
1374                         (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1375                 refcount_release(&tp->t_fb->tfb_refcnt);
1376                 uma_zfree(V_tcpcb_zone, tm);
1377                 return (NULL);
1378         }
1379 #endif
1380
1381 #ifdef VIMAGE
1382         tp->t_vnet = inp->inp_vnet;
1383 #endif
1384         tp->t_timers = &tm->tt;
1385         /*      LIST_INIT(&tp->t_segq); */      /* XXX covered by M_ZERO */
1386         tp->t_maxseg =
1387 #ifdef INET6
1388                 isipv6 ? V_tcp_v6mssdflt :
1389 #endif /* INET6 */
1390                 V_tcp_mssdflt;
1391
1392         /* Set up our timeouts. */
1393         callout_init(&tp->t_timers->tt_rexmt, 1);
1394         callout_init(&tp->t_timers->tt_persist, 1);
1395         callout_init(&tp->t_timers->tt_keep, 1);
1396         callout_init(&tp->t_timers->tt_2msl, 1);
1397         callout_init(&tp->t_timers->tt_delack, 1);
1398
1399         if (V_tcp_do_rfc1323)
1400                 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
1401         if (V_tcp_do_sack)
1402                 tp->t_flags |= TF_SACK_PERMIT;
1403         TAILQ_INIT(&tp->snd_holes);
1404         /*
1405          * The tcpcb will hold a reference on its inpcb until tcp_discardcb()
1406          * is called.
1407          */
1408         in_pcbref(inp); /* Reference for tcpcb */
1409         tp->t_inpcb = inp;
1410
1411         /*
1412          * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
1413          * rtt estimate.  Set rttvar so that srtt + 4 * rttvar gives
1414          * reasonable initial retransmit time.
1415          */
1416         tp->t_srtt = TCPTV_SRTTBASE;
1417         tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
1418         tp->t_rttmin = tcp_rexmit_min;
1419         tp->t_rxtcur = TCPTV_RTOBASE;
1420         tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1421         tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1422         tp->t_rcvtime = ticks;
1423         /*
1424          * IPv4 TTL initialization is necessary for an IPv6 socket as well,
1425          * because the socket may be bound to an IPv6 wildcard address,
1426          * which may match an IPv4-mapped IPv6 address.
1427          */
1428         inp->inp_ip_ttl = V_ip_defttl;
1429         inp->inp_ppcb = tp;
1430 #ifdef TCPPCAP
1431         /*
1432          * Init the TCP PCAP queues.
1433          */
1434         tcp_pcap_tcpcb_init(tp);
1435 #endif
1436 #ifdef TCP_BLACKBOX
1437         /* Initialize the per-TCPCB log data. */
1438         tcp_log_tcpcbinit(tp);
1439 #endif
1440         if (tp->t_fb->tfb_tcp_fb_init) {
1441                 (*tp->t_fb->tfb_tcp_fb_init)(tp);
1442         }
1443         return (tp);            /* XXX */
1444 }
1445
1446 /*
1447  * Switch the congestion control algorithm back to NewReno for any active
1448  * control blocks using an algorithm which is about to go away.
1449  * This ensures the CC framework can allow the unload to proceed without leaving
1450  * any dangling pointers which would trigger a panic.
1451  * Returning non-zero would inform the CC framework that something went wrong
1452  * and it would be unsafe to allow the unload to proceed. However, there is no
1453  * way for this to occur with this implementation so we always return zero.
1454  */
1455 int
1456 tcp_ccalgounload(struct cc_algo *unload_algo)
1457 {
1458         struct cc_algo *tmpalgo;
1459         struct inpcb *inp;
1460         struct tcpcb *tp;
1461         VNET_ITERATOR_DECL(vnet_iter);
1462
1463         /*
1464          * Check all active control blocks across all network stacks and change
1465          * any that are using "unload_algo" back to NewReno. If "unload_algo"
1466          * requires cleanup code to be run, call it.
1467          */
1468         VNET_LIST_RLOCK();
1469         VNET_FOREACH(vnet_iter) {
1470                 CURVNET_SET(vnet_iter);
1471                 INP_INFO_WLOCK(&V_tcbinfo);
1472                 /*
1473                  * New connections already part way through being initialised
1474                  * with the CC algo we're removing will not race with this code
1475                  * because the INP_INFO_WLOCK is held during initialisation. We
1476                  * therefore don't enter the loop below until the connection
1477                  * list has stabilised.
1478                  */
1479                 LIST_FOREACH(inp, &V_tcb, inp_list) {
1480                         INP_WLOCK(inp);
1481                         /* Important to skip tcptw structs. */
1482                         if (!(inp->inp_flags & INP_TIMEWAIT) &&
1483                             (tp = intotcpcb(inp)) != NULL) {
1484                                 /*
1485                                  * By holding INP_WLOCK here, we are assured
1486                                  * that the connection is not currently
1487                                  * executing inside the CC module's functions
1488                                  * i.e. it is safe to make the switch back to
1489                                  * NewReno.
1490                                  */
1491                                 if (CC_ALGO(tp) == unload_algo) {
1492                                         tmpalgo = CC_ALGO(tp);
1493                                         /* NewReno does not require any init. */
1494                                         CC_ALGO(tp) = &newreno_cc_algo;
1495                                         if (tmpalgo->cb_destroy != NULL)
1496                                                 tmpalgo->cb_destroy(tp->ccv);
1497                                 }
1498                         }
1499                         INP_WUNLOCK(inp);
1500                 }
1501                 INP_INFO_WUNLOCK(&V_tcbinfo);
1502                 CURVNET_RESTORE();
1503         }
1504         VNET_LIST_RUNLOCK();
1505
1506         return (0);
1507 }
1508
1509 /*
1510  * Drop a TCP connection, reporting
1511  * the specified error.  If connection is synchronized,
1512  * then send a RST to peer.
1513  */
1514 struct tcpcb *
1515 tcp_drop(struct tcpcb *tp, int errno)
1516 {
1517         struct socket *so = tp->t_inpcb->inp_socket;
1518
1519         INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1520         INP_WLOCK_ASSERT(tp->t_inpcb);
1521
1522         if (TCPS_HAVERCVDSYN(tp->t_state)) {
1523                 tcp_state_change(tp, TCPS_CLOSED);
1524                 (void) tp->t_fb->tfb_tcp_output(tp);
1525                 TCPSTAT_INC(tcps_drops);
1526         } else
1527                 TCPSTAT_INC(tcps_conndrops);
1528         if (errno == ETIMEDOUT && tp->t_softerror)
1529                 errno = tp->t_softerror;
1530         so->so_error = errno;
1531         return (tcp_close(tp));
1532 }
1533
1534 void
1535 tcp_discardcb(struct tcpcb *tp)
1536 {
1537         struct inpcb *inp = tp->t_inpcb;
1538         struct socket *so = inp->inp_socket;
1539 #ifdef INET6
1540         int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1541 #endif /* INET6 */
1542         int released;
1543
1544         INP_WLOCK_ASSERT(inp);
1545
1546         /*
1547          * Make sure that all of our timers are stopped before we delete the
1548          * PCB.
1549          *
1550          * If stopping a timer fails, we schedule a discard function in same
1551          * callout, and the last discard function called will take care of
1552          * deleting the tcpcb.
1553          */
1554         tp->t_timers->tt_draincnt = 0;
1555         tcp_timer_stop(tp, TT_REXMT);
1556         tcp_timer_stop(tp, TT_PERSIST);
1557         tcp_timer_stop(tp, TT_KEEP);
1558         tcp_timer_stop(tp, TT_2MSL);
1559         tcp_timer_stop(tp, TT_DELACK);
1560         if (tp->t_fb->tfb_tcp_timer_stop_all) {
1561                 /*
1562                  * Call the stop-all function of the methods,
1563                  * this function should call the tcp_timer_stop()
1564                  * method with each of the function specific timeouts.
1565                  * That stop will be called via the tfb_tcp_timer_stop()
1566                  * which should use the async drain function of the
1567                  * callout system (see tcp_var.h).
1568                  */
1569                 tp->t_fb->tfb_tcp_timer_stop_all(tp);
1570         }
1571
1572         /*
1573          * If we got enough samples through the srtt filter,
1574          * save the rtt and rttvar in the routing entry.
1575          * 'Enough' is arbitrarily defined as 4 rtt samples.
1576          * 4 samples is enough for the srtt filter to converge
1577          * to within enough % of the correct value; fewer samples
1578          * and we could save a bogus rtt. The danger is not high
1579          * as tcp quickly recovers from everything.
1580          * XXX: Works very well but needs some more statistics!
1581          */
1582         if (tp->t_rttupdated >= 4) {
1583                 struct hc_metrics_lite metrics;
1584                 uint32_t ssthresh;
1585
1586                 bzero(&metrics, sizeof(metrics));
1587                 /*
1588                  * Update the ssthresh always when the conditions below
1589                  * are satisfied. This gives us better new start value
1590                  * for the congestion avoidance for new connections.
1591                  * ssthresh is only set if packet loss occurred on a session.
1592                  *
1593                  * XXXRW: 'so' may be NULL here, and/or socket buffer may be
1594                  * being torn down.  Ideally this code would not use 'so'.
1595                  */
1596                 ssthresh = tp->snd_ssthresh;
1597                 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
1598                         /*
1599                          * convert the limit from user data bytes to
1600                          * packets then to packet data bytes.
1601                          */
1602                         ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
1603                         if (ssthresh < 2)
1604                                 ssthresh = 2;
1605                         ssthresh *= (tp->t_maxseg +
1606 #ifdef INET6
1607                             (isipv6 ? sizeof (struct ip6_hdr) +
1608                                 sizeof (struct tcphdr) :
1609 #endif
1610                                 sizeof (struct tcpiphdr)
1611 #ifdef INET6
1612                             )
1613 #endif
1614                             );
1615                 } else
1616                         ssthresh = 0;
1617                 metrics.rmx_ssthresh = ssthresh;
1618
1619                 metrics.rmx_rtt = tp->t_srtt;
1620                 metrics.rmx_rttvar = tp->t_rttvar;
1621                 metrics.rmx_cwnd = tp->snd_cwnd;
1622                 metrics.rmx_sendpipe = 0;
1623                 metrics.rmx_recvpipe = 0;
1624
1625                 tcp_hc_update(&inp->inp_inc, &metrics);
1626         }
1627
1628         /* free the reassembly queue, if any */
1629         tcp_reass_flush(tp);
1630
1631 #ifdef TCP_OFFLOAD
1632         /* Disconnect offload device, if any. */
1633         if (tp->t_flags & TF_TOE)
1634                 tcp_offload_detach(tp);
1635 #endif
1636
1637         tcp_free_sackholes(tp);
1638
1639 #ifdef TCPPCAP
1640         /* Free the TCP PCAP queues. */
1641         tcp_pcap_drain(&(tp->t_inpkts));
1642         tcp_pcap_drain(&(tp->t_outpkts));
1643 #endif
1644
1645         /* Allow the CC algorithm to clean up after itself. */
1646         if (CC_ALGO(tp)->cb_destroy != NULL)
1647                 CC_ALGO(tp)->cb_destroy(tp->ccv);
1648
1649 #ifdef TCP_HHOOK
1650         khelp_destroy_osd(tp->osd);
1651 #endif
1652
1653         CC_ALGO(tp) = NULL;
1654         inp->inp_ppcb = NULL;
1655         if (tp->t_timers->tt_draincnt == 0) {
1656                 /* We own the last reference on tcpcb, let's free it. */
1657 #ifdef TCP_BLACKBOX
1658                 tcp_log_tcpcbfini(tp);
1659 #endif
1660                 TCPSTATES_DEC(tp->t_state);
1661                 if (tp->t_fb->tfb_tcp_fb_fini)
1662                         (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1663                 refcount_release(&tp->t_fb->tfb_refcnt);
1664                 tp->t_inpcb = NULL;
1665                 uma_zfree(V_tcpcb_zone, tp);
1666                 released = in_pcbrele_wlocked(inp);
1667                 KASSERT(!released, ("%s: inp %p should not have been released "
1668                         "here", __func__, inp));
1669         }
1670 }
1671
1672 void
1673 tcp_timer_discard(void *ptp)
1674 {
1675         struct inpcb *inp;
1676         struct tcpcb *tp;
1677
1678         tp = (struct tcpcb *)ptp;
1679         CURVNET_SET(tp->t_vnet);
1680         INP_INFO_RLOCK(&V_tcbinfo);
1681         inp = tp->t_inpcb;
1682         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL",
1683                 __func__, tp));
1684         INP_WLOCK(inp);
1685         KASSERT((tp->t_timers->tt_flags & TT_STOPPED) != 0,
1686                 ("%s: tcpcb has to be stopped here", __func__));
1687         tp->t_timers->tt_draincnt--;
1688         if (tp->t_timers->tt_draincnt == 0) {
1689                 /* We own the last reference on this tcpcb, let's free it. */
1690 #ifdef TCP_BLACKBOX
1691                 tcp_log_tcpcbfini(tp);
1692 #endif
1693                 TCPSTATES_DEC(tp->t_state);
1694                 if (tp->t_fb->tfb_tcp_fb_fini)
1695                         (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1696                 refcount_release(&tp->t_fb->tfb_refcnt);
1697                 tp->t_inpcb = NULL;
1698                 uma_zfree(V_tcpcb_zone, tp);
1699                 if (in_pcbrele_wlocked(inp)) {
1700                         INP_INFO_RUNLOCK(&V_tcbinfo);
1701                         CURVNET_RESTORE();
1702                         return;
1703                 }
1704         }
1705         INP_WUNLOCK(inp);
1706         INP_INFO_RUNLOCK(&V_tcbinfo);
1707         CURVNET_RESTORE();
1708 }
1709
1710 /*
1711  * Attempt to close a TCP control block, marking it as dropped, and freeing
1712  * the socket if we hold the only reference.
1713  */
1714 struct tcpcb *
1715 tcp_close(struct tcpcb *tp)
1716 {
1717         struct inpcb *inp = tp->t_inpcb;
1718         struct socket *so;
1719
1720         INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1721         INP_WLOCK_ASSERT(inp);
1722
1723 #ifdef TCP_OFFLOAD
1724         if (tp->t_state == TCPS_LISTEN)
1725                 tcp_offload_listen_stop(tp);
1726 #endif
1727         /*
1728          * This releases the TFO pending counter resource for TFO listen
1729          * sockets as well as passively-created TFO sockets that transition
1730          * from SYN_RECEIVED to CLOSED.
1731          */
1732         if (tp->t_tfo_pending) {
1733                 tcp_fastopen_decrement_counter(tp->t_tfo_pending);
1734                 tp->t_tfo_pending = NULL;
1735         }
1736         in_pcbdrop(inp);
1737         TCPSTAT_INC(tcps_closed);
1738         if (tp->t_state != TCPS_CLOSED)
1739                 tcp_state_change(tp, TCPS_CLOSED);
1740         KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
1741         so = inp->inp_socket;
1742         soisdisconnected(so);
1743         if (inp->inp_flags & INP_SOCKREF) {
1744                 KASSERT(so->so_state & SS_PROTOREF,
1745                     ("tcp_close: !SS_PROTOREF"));
1746                 inp->inp_flags &= ~INP_SOCKREF;
1747                 INP_WUNLOCK(inp);
1748                 SOCK_LOCK(so);
1749                 so->so_state &= ~SS_PROTOREF;
1750                 sofree(so);
1751                 return (NULL);
1752         }
1753         return (tp);
1754 }
1755
1756 void
1757 tcp_drain(void)
1758 {
1759         VNET_ITERATOR_DECL(vnet_iter);
1760
1761         if (!do_tcpdrain)
1762                 return;
1763
1764         VNET_LIST_RLOCK_NOSLEEP();
1765         VNET_FOREACH(vnet_iter) {
1766                 CURVNET_SET(vnet_iter);
1767                 struct inpcb *inpb;
1768                 struct tcpcb *tcpb;
1769
1770         /*
1771          * Walk the tcpbs, if existing, and flush the reassembly queue,
1772          * if there is one...
1773          * XXX: The "Net/3" implementation doesn't imply that the TCP
1774          *      reassembly queue should be flushed, but in a situation
1775          *      where we're really low on mbufs, this is potentially
1776          *      useful.
1777          */
1778                 INP_INFO_WLOCK(&V_tcbinfo);
1779                 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
1780                         if (inpb->inp_flags & INP_TIMEWAIT)
1781                                 continue;
1782                         INP_WLOCK(inpb);
1783                         if ((tcpb = intotcpcb(inpb)) != NULL) {
1784                                 tcp_reass_flush(tcpb);
1785                                 tcp_clean_sackreport(tcpb);
1786 #ifdef TCP_BLACKBOX
1787                                 tcp_log_drain(tcpb);
1788 #endif
1789 #ifdef TCPPCAP
1790                                 if (tcp_pcap_aggressive_free) {
1791                                         /* Free the TCP PCAP queues. */
1792                                         tcp_pcap_drain(&(tcpb->t_inpkts));
1793                                         tcp_pcap_drain(&(tcpb->t_outpkts));
1794                                 }
1795 #endif
1796                         }
1797                         INP_WUNLOCK(inpb);
1798                 }
1799                 INP_INFO_WUNLOCK(&V_tcbinfo);
1800                 CURVNET_RESTORE();
1801         }
1802         VNET_LIST_RUNLOCK_NOSLEEP();
1803 }
1804
1805 /*
1806  * Notify a tcp user of an asynchronous error;
1807  * store error as soft error, but wake up user
1808  * (for now, won't do anything until can select for soft error).
1809  *
1810  * Do not wake up user since there currently is no mechanism for
1811  * reporting soft errors (yet - a kqueue filter may be added).
1812  */
1813 static struct inpcb *
1814 tcp_notify(struct inpcb *inp, int error)
1815 {
1816         struct tcpcb *tp;
1817
1818         INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1819         INP_WLOCK_ASSERT(inp);
1820
1821         if ((inp->inp_flags & INP_TIMEWAIT) ||
1822             (inp->inp_flags & INP_DROPPED))
1823                 return (inp);
1824
1825         tp = intotcpcb(inp);
1826         KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
1827
1828         /*
1829          * Ignore some errors if we are hooked up.
1830          * If connection hasn't completed, has retransmitted several times,
1831          * and receives a second error, give up now.  This is better
1832          * than waiting a long time to establish a connection that
1833          * can never complete.
1834          */
1835         if (tp->t_state == TCPS_ESTABLISHED &&
1836             (error == EHOSTUNREACH || error == ENETUNREACH ||
1837              error == EHOSTDOWN)) {
1838                 if (inp->inp_route.ro_rt) {
1839                         RTFREE(inp->inp_route.ro_rt);
1840                         inp->inp_route.ro_rt = (struct rtentry *)NULL;
1841                 }
1842                 return (inp);
1843         } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1844             tp->t_softerror) {
1845                 tp = tcp_drop(tp, error);
1846                 if (tp != NULL)
1847                         return (inp);
1848                 else
1849                         return (NULL);
1850         } else {
1851                 tp->t_softerror = error;
1852                 return (inp);
1853         }
1854 #if 0
1855         wakeup( &so->so_timeo);
1856         sorwakeup(so);
1857         sowwakeup(so);
1858 #endif
1859 }
1860
1861 static int
1862 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1863 {
1864         int error, i, m, n, pcb_count;
1865         struct inpcb *inp, **inp_list;
1866         inp_gen_t gencnt;
1867         struct xinpgen xig;
1868
1869         /*
1870          * The process of preparing the TCB list is too time-consuming and
1871          * resource-intensive to repeat twice on every request.
1872          */
1873         if (req->oldptr == NULL) {
1874                 n = V_tcbinfo.ipi_count +
1875                     counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
1876                 n += imax(n / 8, 10);
1877                 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
1878                 return (0);
1879         }
1880
1881         if (req->newptr != NULL)
1882                 return (EPERM);
1883
1884         /*
1885          * OK, now we're committed to doing something.
1886          */
1887         INP_LIST_RLOCK(&V_tcbinfo);
1888         gencnt = V_tcbinfo.ipi_gencnt;
1889         n = V_tcbinfo.ipi_count;
1890         INP_LIST_RUNLOCK(&V_tcbinfo);
1891
1892         m = counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
1893
1894         error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
1895                 + (n + m) * sizeof(struct xtcpcb));
1896         if (error != 0)
1897                 return (error);
1898
1899         xig.xig_len = sizeof xig;
1900         xig.xig_count = n + m;
1901         xig.xig_gen = gencnt;
1902         xig.xig_sogen = so_gencnt;
1903         error = SYSCTL_OUT(req, &xig, sizeof xig);
1904         if (error)
1905                 return (error);
1906
1907         error = syncache_pcblist(req, m, &pcb_count);
1908         if (error)
1909                 return (error);
1910
1911         inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
1912
1913         INP_INFO_WLOCK(&V_tcbinfo);
1914         for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
1915             inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
1916                 INP_WLOCK(inp);
1917                 if (inp->inp_gencnt <= gencnt) {
1918                         /*
1919                          * XXX: This use of cr_cansee(), introduced with
1920                          * TCP state changes, is not quite right, but for
1921                          * now, better than nothing.
1922                          */
1923                         if (inp->inp_flags & INP_TIMEWAIT) {
1924                                 if (intotw(inp) != NULL)
1925                                         error = cr_cansee(req->td->td_ucred,
1926                                             intotw(inp)->tw_cred);
1927                                 else
1928                                         error = EINVAL; /* Skip this inp. */
1929                         } else
1930                                 error = cr_canseeinpcb(req->td->td_ucred, inp);
1931                         if (error == 0) {
1932                                 in_pcbref(inp);
1933                                 inp_list[i++] = inp;
1934                         }
1935                 }
1936                 INP_WUNLOCK(inp);
1937         }
1938         INP_INFO_WUNLOCK(&V_tcbinfo);
1939         n = i;
1940
1941         error = 0;
1942         for (i = 0; i < n; i++) {
1943                 inp = inp_list[i];
1944                 INP_RLOCK(inp);
1945                 if (inp->inp_gencnt <= gencnt) {
1946                         struct xtcpcb xt;
1947
1948                         tcp_inptoxtp(inp, &xt);
1949                         INP_RUNLOCK(inp);
1950                         error = SYSCTL_OUT(req, &xt, sizeof xt);
1951                 } else
1952                         INP_RUNLOCK(inp);
1953         }
1954         INP_INFO_RLOCK(&V_tcbinfo);
1955         for (i = 0; i < n; i++) {
1956                 inp = inp_list[i];
1957                 INP_RLOCK(inp);
1958                 if (!in_pcbrele_rlocked(inp))
1959                         INP_RUNLOCK(inp);
1960         }
1961         INP_INFO_RUNLOCK(&V_tcbinfo);
1962
1963         if (!error) {
1964                 /*
1965                  * Give the user an updated idea of our state.
1966                  * If the generation differs from what we told
1967                  * her before, she knows that something happened
1968                  * while we were processing this request, and it
1969                  * might be necessary to retry.
1970                  */
1971                 INP_LIST_RLOCK(&V_tcbinfo);
1972                 xig.xig_gen = V_tcbinfo.ipi_gencnt;
1973                 xig.xig_sogen = so_gencnt;
1974                 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
1975                 INP_LIST_RUNLOCK(&V_tcbinfo);
1976                 error = SYSCTL_OUT(req, &xig, sizeof xig);
1977         }
1978         free(inp_list, M_TEMP);
1979         return (error);
1980 }
1981
1982 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
1983     CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
1984     tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1985
1986 #ifdef INET
1987 static int
1988 tcp_getcred(SYSCTL_HANDLER_ARGS)
1989 {
1990         struct xucred xuc;
1991         struct sockaddr_in addrs[2];
1992         struct inpcb *inp;
1993         int error;
1994
1995         error = priv_check(req->td, PRIV_NETINET_GETCRED);
1996         if (error)
1997                 return (error);
1998         error = SYSCTL_IN(req, addrs, sizeof(addrs));
1999         if (error)
2000                 return (error);
2001         inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
2002             addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
2003         if (inp != NULL) {
2004                 if (inp->inp_socket == NULL)
2005                         error = ENOENT;
2006                 if (error == 0)
2007                         error = cr_canseeinpcb(req->td->td_ucred, inp);
2008                 if (error == 0)
2009                         cru2x(inp->inp_cred, &xuc);
2010                 INP_RUNLOCK(inp);
2011         } else
2012                 error = ENOENT;
2013         if (error == 0)
2014                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2015         return (error);
2016 }
2017
2018 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
2019     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
2020     tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
2021 #endif /* INET */
2022
2023 #ifdef INET6
2024 static int
2025 tcp6_getcred(SYSCTL_HANDLER_ARGS)
2026 {
2027         struct xucred xuc;
2028         struct sockaddr_in6 addrs[2];
2029         struct inpcb *inp;
2030         int error;
2031 #ifdef INET
2032         int mapped = 0;
2033 #endif
2034
2035         error = priv_check(req->td, PRIV_NETINET_GETCRED);
2036         if (error)
2037                 return (error);
2038         error = SYSCTL_IN(req, addrs, sizeof(addrs));
2039         if (error)
2040                 return (error);
2041         if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
2042             (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
2043                 return (error);
2044         }
2045         if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
2046 #ifdef INET
2047                 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
2048                         mapped = 1;
2049                 else
2050 #endif
2051                         return (EINVAL);
2052         }
2053
2054 #ifdef INET
2055         if (mapped == 1)
2056                 inp = in_pcblookup(&V_tcbinfo,
2057                         *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
2058                         addrs[1].sin6_port,
2059                         *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
2060                         addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
2061         else
2062 #endif
2063                 inp = in6_pcblookup(&V_tcbinfo,
2064                         &addrs[1].sin6_addr, addrs[1].sin6_port,
2065                         &addrs[0].sin6_addr, addrs[0].sin6_port,
2066                         INPLOOKUP_RLOCKPCB, NULL);
2067         if (inp != NULL) {
2068                 if (inp->inp_socket == NULL)
2069                         error = ENOENT;
2070                 if (error == 0)
2071                         error = cr_canseeinpcb(req->td->td_ucred, inp);
2072                 if (error == 0)
2073                         cru2x(inp->inp_cred, &xuc);
2074                 INP_RUNLOCK(inp);
2075         } else
2076                 error = ENOENT;
2077         if (error == 0)
2078                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2079         return (error);
2080 }
2081
2082 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
2083     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
2084     tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
2085 #endif /* INET6 */
2086
2087
2088 #ifdef INET
2089 void
2090 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
2091 {
2092         struct ip *ip = vip;
2093         struct tcphdr *th;
2094         struct in_addr faddr;
2095         struct inpcb *inp;
2096         struct tcpcb *tp;
2097         struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2098         struct icmp *icp;
2099         struct in_conninfo inc;
2100         tcp_seq icmp_tcp_seq;
2101         int mtu;
2102
2103         faddr = ((struct sockaddr_in *)sa)->sin_addr;
2104         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
2105                 return;
2106
2107         if (cmd == PRC_MSGSIZE)
2108                 notify = tcp_mtudisc_notify;
2109         else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
2110                 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
2111                 cmd == PRC_TIMXCEED_INTRANS) && ip)
2112                 notify = tcp_drop_syn_sent;
2113
2114         /*
2115          * Hostdead is ugly because it goes linearly through all PCBs.
2116          * XXX: We never get this from ICMP, otherwise it makes an
2117          * excellent DoS attack on machines with many connections.
2118          */
2119         else if (cmd == PRC_HOSTDEAD)
2120                 ip = NULL;
2121         else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
2122                 return;
2123
2124         if (ip == NULL) {
2125                 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
2126                 return;
2127         }
2128
2129         icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip));
2130         th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
2131         INP_INFO_RLOCK(&V_tcbinfo);
2132         inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, ip->ip_src,
2133             th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
2134         if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
2135                 /* signal EHOSTDOWN, as it flushes the cached route */
2136                 inp = (*notify)(inp, EHOSTDOWN);
2137                 goto out;
2138         }
2139         icmp_tcp_seq = th->th_seq;
2140         if (inp != NULL)  {
2141                 if (!(inp->inp_flags & INP_TIMEWAIT) &&
2142                     !(inp->inp_flags & INP_DROPPED) &&
2143                     !(inp->inp_socket == NULL)) {
2144                         tp = intotcpcb(inp);
2145                         if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
2146                             SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
2147                                 if (cmd == PRC_MSGSIZE) {
2148                                         /*
2149                                          * MTU discovery:
2150                                          * If we got a needfrag set the MTU
2151                                          * in the route to the suggested new
2152                                          * value (if given) and then notify.
2153                                          */
2154                                         mtu = ntohs(icp->icmp_nextmtu);
2155                                         /*
2156                                          * If no alternative MTU was
2157                                          * proposed, try the next smaller
2158                                          * one.
2159                                          */
2160                                         if (!mtu)
2161                                                 mtu = ip_next_mtu(
2162                                                     ntohs(ip->ip_len), 1);
2163                                         if (mtu < V_tcp_minmss +
2164                                             sizeof(struct tcpiphdr))
2165                                                 mtu = V_tcp_minmss +
2166                                                     sizeof(struct tcpiphdr);
2167                                         /*
2168                                          * Only process the offered MTU if it
2169                                          * is smaller than the current one.
2170                                          */
2171                                         if (mtu < tp->t_maxseg +
2172                                             sizeof(struct tcpiphdr)) {
2173                                                 bzero(&inc, sizeof(inc));
2174                                                 inc.inc_faddr = faddr;
2175                                                 inc.inc_fibnum =
2176                                                     inp->inp_inc.inc_fibnum;
2177                                                 tcp_hc_updatemtu(&inc, mtu);
2178                                                 tcp_mtudisc(inp, mtu);
2179                                         }
2180                                 } else
2181                                         inp = (*notify)(inp,
2182                                             inetctlerrmap[cmd]);
2183                         }
2184                 }
2185         } else {
2186                 bzero(&inc, sizeof(inc));
2187                 inc.inc_fport = th->th_dport;
2188                 inc.inc_lport = th->th_sport;
2189                 inc.inc_faddr = faddr;
2190                 inc.inc_laddr = ip->ip_src;
2191                 syncache_unreach(&inc, icmp_tcp_seq);
2192         }
2193 out:
2194         if (inp != NULL)
2195                 INP_WUNLOCK(inp);
2196         INP_INFO_RUNLOCK(&V_tcbinfo);
2197 }
2198 #endif /* INET */
2199
2200 #ifdef INET6
2201 void
2202 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
2203 {
2204         struct in6_addr *dst;
2205         struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2206         struct ip6_hdr *ip6;
2207         struct mbuf *m;
2208         struct inpcb *inp;
2209         struct tcpcb *tp;
2210         struct icmp6_hdr *icmp6;
2211         struct ip6ctlparam *ip6cp = NULL;
2212         const struct sockaddr_in6 *sa6_src = NULL;
2213         struct in_conninfo inc;
2214         struct tcp_ports {
2215                 uint16_t th_sport;
2216                 uint16_t th_dport;
2217         } t_ports;
2218         tcp_seq icmp_tcp_seq;
2219         unsigned int mtu;
2220         unsigned int off;
2221
2222         if (sa->sa_family != AF_INET6 ||
2223             sa->sa_len != sizeof(struct sockaddr_in6))
2224                 return;
2225
2226         /* if the parameter is from icmp6, decode it. */
2227         if (d != NULL) {
2228                 ip6cp = (struct ip6ctlparam *)d;
2229                 icmp6 = ip6cp->ip6c_icmp6;
2230                 m = ip6cp->ip6c_m;
2231                 ip6 = ip6cp->ip6c_ip6;
2232                 off = ip6cp->ip6c_off;
2233                 sa6_src = ip6cp->ip6c_src;
2234                 dst = ip6cp->ip6c_finaldst;
2235         } else {
2236                 m = NULL;
2237                 ip6 = NULL;
2238                 off = 0;        /* fool gcc */
2239                 sa6_src = &sa6_any;
2240                 dst = NULL;
2241         }
2242
2243         if (cmd == PRC_MSGSIZE)
2244                 notify = tcp_mtudisc_notify;
2245         else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
2246                 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
2247                 cmd == PRC_TIMXCEED_INTRANS) && ip6 != NULL)
2248                 notify = tcp_drop_syn_sent;
2249
2250         /*
2251          * Hostdead is ugly because it goes linearly through all PCBs.
2252          * XXX: We never get this from ICMP, otherwise it makes an
2253          * excellent DoS attack on machines with many connections.
2254          */
2255         else if (cmd == PRC_HOSTDEAD)
2256                 ip6 = NULL;
2257         else if ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)
2258                 return;
2259
2260         if (ip6 == NULL) {
2261                 in6_pcbnotify(&V_tcbinfo, sa, 0,
2262                               (const struct sockaddr *)sa6_src,
2263                               0, cmd, NULL, notify);
2264                 return;
2265         }
2266
2267         /* Check if we can safely get the ports from the tcp hdr */
2268         if (m == NULL ||
2269             (m->m_pkthdr.len <
2270                 (int32_t) (off + sizeof(struct tcp_ports)))) {
2271                 return;
2272         }
2273         bzero(&t_ports, sizeof(struct tcp_ports));
2274         m_copydata(m, off, sizeof(struct tcp_ports), (caddr_t)&t_ports);
2275         INP_INFO_RLOCK(&V_tcbinfo);
2276         inp = in6_pcblookup(&V_tcbinfo, &ip6->ip6_dst, t_ports.th_dport,
2277             &ip6->ip6_src, t_ports.th_sport, INPLOOKUP_WLOCKPCB, NULL);
2278         if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
2279                 /* signal EHOSTDOWN, as it flushes the cached route */
2280                 inp = (*notify)(inp, EHOSTDOWN);
2281                 goto out;
2282         }
2283         off += sizeof(struct tcp_ports);
2284         if (m->m_pkthdr.len < (int32_t) (off + sizeof(tcp_seq))) {
2285                 goto out;
2286         }
2287         m_copydata(m, off, sizeof(tcp_seq), (caddr_t)&icmp_tcp_seq);
2288         if (inp != NULL)  {
2289                 if (!(inp->inp_flags & INP_TIMEWAIT) &&
2290                     !(inp->inp_flags & INP_DROPPED) &&
2291                     !(inp->inp_socket == NULL)) {
2292                         tp = intotcpcb(inp);
2293                         if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
2294                             SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
2295                                 if (cmd == PRC_MSGSIZE) {
2296                                         /*
2297                                          * MTU discovery:
2298                                          * If we got a needfrag set the MTU
2299                                          * in the route to the suggested new
2300                                          * value (if given) and then notify.
2301                                          */
2302                                         mtu = ntohl(icmp6->icmp6_mtu);
2303                                         /*
2304                                          * If no alternative MTU was
2305                                          * proposed, or the proposed
2306                                          * MTU was too small, set to
2307                                          * the min.
2308                                          */
2309                                         if (mtu < IPV6_MMTU)
2310                                                 mtu = IPV6_MMTU - 8;
2311                                         bzero(&inc, sizeof(inc));
2312                                         inc.inc_fibnum = M_GETFIB(m);
2313                                         inc.inc_flags |= INC_ISIPV6;
2314                                         inc.inc6_faddr = *dst;
2315                                         if (in6_setscope(&inc.inc6_faddr,
2316                                                 m->m_pkthdr.rcvif, NULL))
2317                                                 goto out;
2318                                         /*
2319                                          * Only process the offered MTU if it
2320                                          * is smaller than the current one.
2321                                          */
2322                                         if (mtu < tp->t_maxseg +
2323                                             sizeof (struct tcphdr) +
2324                                             sizeof (struct ip6_hdr)) {
2325                                                 tcp_hc_updatemtu(&inc, mtu);
2326                                                 tcp_mtudisc(inp, mtu);
2327                                                 ICMP6STAT_INC(icp6s_pmtuchg);
2328                                         }
2329                                 } else
2330                                         inp = (*notify)(inp,
2331                                             inet6ctlerrmap[cmd]);
2332                         }
2333                 }
2334         } else {
2335                 bzero(&inc, sizeof(inc));
2336                 inc.inc_fibnum = M_GETFIB(m);
2337                 inc.inc_flags |= INC_ISIPV6;
2338                 inc.inc_fport = t_ports.th_dport;
2339                 inc.inc_lport = t_ports.th_sport;
2340                 inc.inc6_faddr = *dst;
2341                 inc.inc6_laddr = ip6->ip6_src;
2342                 syncache_unreach(&inc, icmp_tcp_seq);
2343         }
2344 out:
2345         if (inp != NULL)
2346                 INP_WUNLOCK(inp);
2347         INP_INFO_RUNLOCK(&V_tcbinfo);
2348 }
2349 #endif /* INET6 */
2350
2351
2352 /*
2353  * Following is where TCP initial sequence number generation occurs.
2354  *
2355  * There are two places where we must use initial sequence numbers:
2356  * 1.  In SYN-ACK packets.
2357  * 2.  In SYN packets.
2358  *
2359  * All ISNs for SYN-ACK packets are generated by the syncache.  See
2360  * tcp_syncache.c for details.
2361  *
2362  * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
2363  * depends on this property.  In addition, these ISNs should be
2364  * unguessable so as to prevent connection hijacking.  To satisfy
2365  * the requirements of this situation, the algorithm outlined in
2366  * RFC 1948 is used, with only small modifications.
2367  *
2368  * Implementation details:
2369  *
2370  * Time is based off the system timer, and is corrected so that it
2371  * increases by one megabyte per second.  This allows for proper
2372  * recycling on high speed LANs while still leaving over an hour
2373  * before rollover.
2374  *
2375  * As reading the *exact* system time is too expensive to be done
2376  * whenever setting up a TCP connection, we increment the time
2377  * offset in two ways.  First, a small random positive increment
2378  * is added to isn_offset for each connection that is set up.
2379  * Second, the function tcp_isn_tick fires once per clock tick
2380  * and increments isn_offset as necessary so that sequence numbers
2381  * are incremented at approximately ISN_BYTES_PER_SECOND.  The
2382  * random positive increments serve only to ensure that the same
2383  * exact sequence number is never sent out twice (as could otherwise
2384  * happen when a port is recycled in less than the system tick
2385  * interval.)
2386  *
2387  * net.inet.tcp.isn_reseed_interval controls the number of seconds
2388  * between seeding of isn_secret.  This is normally set to zero,
2389  * as reseeding should not be necessary.
2390  *
2391  * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
2392  * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock.  In
2393  * general, this means holding an exclusive (write) lock.
2394  */
2395
2396 #define ISN_BYTES_PER_SECOND 1048576
2397 #define ISN_STATIC_INCREMENT 4096
2398 #define ISN_RANDOM_INCREMENT (4096 - 1)
2399
2400 static VNET_DEFINE(u_char, isn_secret[32]);
2401 static VNET_DEFINE(int, isn_last);
2402 static VNET_DEFINE(int, isn_last_reseed);
2403 static VNET_DEFINE(u_int32_t, isn_offset);
2404 static VNET_DEFINE(u_int32_t, isn_offset_old);
2405
2406 #define V_isn_secret                    VNET(isn_secret)
2407 #define V_isn_last                      VNET(isn_last)
2408 #define V_isn_last_reseed               VNET(isn_last_reseed)
2409 #define V_isn_offset                    VNET(isn_offset)
2410 #define V_isn_offset_old                VNET(isn_offset_old)
2411
2412 tcp_seq
2413 tcp_new_isn(struct tcpcb *tp)
2414 {
2415         MD5_CTX isn_ctx;
2416         u_int32_t md5_buffer[4];
2417         tcp_seq new_isn;
2418         u_int32_t projected_offset;
2419
2420         INP_WLOCK_ASSERT(tp->t_inpcb);
2421
2422         ISN_LOCK();
2423         /* Seed if this is the first use, reseed if requested. */
2424         if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
2425              (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
2426                 < (u_int)ticks))) {
2427                 read_random(&V_isn_secret, sizeof(V_isn_secret));
2428                 V_isn_last_reseed = ticks;
2429         }
2430
2431         /* Compute the md5 hash and return the ISN. */
2432         MD5Init(&isn_ctx);
2433         MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
2434         MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
2435 #ifdef INET6
2436         if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
2437                 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
2438                           sizeof(struct in6_addr));
2439                 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
2440                           sizeof(struct in6_addr));
2441         } else
2442 #endif
2443         {
2444                 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
2445                           sizeof(struct in_addr));
2446                 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
2447                           sizeof(struct in_addr));
2448         }
2449         MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
2450         MD5Final((u_char *) &md5_buffer, &isn_ctx);
2451         new_isn = (tcp_seq) md5_buffer[0];
2452         V_isn_offset += ISN_STATIC_INCREMENT +
2453                 (arc4random() & ISN_RANDOM_INCREMENT);
2454         if (ticks != V_isn_last) {
2455                 projected_offset = V_isn_offset_old +
2456                     ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
2457                 if (SEQ_GT(projected_offset, V_isn_offset))
2458                         V_isn_offset = projected_offset;
2459                 V_isn_offset_old = V_isn_offset;
2460                 V_isn_last = ticks;
2461         }
2462         new_isn += V_isn_offset;
2463         ISN_UNLOCK();
2464         return (new_isn);
2465 }
2466
2467 /*
2468  * When a specific ICMP unreachable message is received and the
2469  * connection state is SYN-SENT, drop the connection.  This behavior
2470  * is controlled by the icmp_may_rst sysctl.
2471  */
2472 struct inpcb *
2473 tcp_drop_syn_sent(struct inpcb *inp, int errno)
2474 {
2475         struct tcpcb *tp;
2476
2477         INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
2478         INP_WLOCK_ASSERT(inp);
2479
2480         if ((inp->inp_flags & INP_TIMEWAIT) ||
2481             (inp->inp_flags & INP_DROPPED))
2482                 return (inp);
2483
2484         tp = intotcpcb(inp);
2485         if (tp->t_state != TCPS_SYN_SENT)
2486                 return (inp);
2487
2488         if (IS_FASTOPEN(tp->t_flags))
2489                 tcp_fastopen_disable_path(tp);
2490
2491         tp = tcp_drop(tp, errno);
2492         if (tp != NULL)
2493                 return (inp);
2494         else
2495                 return (NULL);
2496 }
2497
2498 /*
2499  * When `need fragmentation' ICMP is received, update our idea of the MSS
2500  * based on the new value. Also nudge TCP to send something, since we
2501  * know the packet we just sent was dropped.
2502  * This duplicates some code in the tcp_mss() function in tcp_input.c.
2503  */
2504 static struct inpcb *
2505 tcp_mtudisc_notify(struct inpcb *inp, int error)
2506 {
2507
2508         tcp_mtudisc(inp, -1);
2509         return (inp);
2510 }
2511
2512 static void
2513 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
2514 {
2515         struct tcpcb *tp;
2516         struct socket *so;
2517
2518         INP_WLOCK_ASSERT(inp);
2519         if ((inp->inp_flags & INP_TIMEWAIT) ||
2520             (inp->inp_flags & INP_DROPPED))
2521                 return;
2522
2523         tp = intotcpcb(inp);
2524         KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
2525
2526         tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
2527
2528         so = inp->inp_socket;
2529         SOCKBUF_LOCK(&so->so_snd);
2530         /* If the mss is larger than the socket buffer, decrease the mss. */
2531         if (so->so_snd.sb_hiwat < tp->t_maxseg)
2532                 tp->t_maxseg = so->so_snd.sb_hiwat;
2533         SOCKBUF_UNLOCK(&so->so_snd);
2534
2535         TCPSTAT_INC(tcps_mturesent);
2536         tp->t_rtttime = 0;
2537         tp->snd_nxt = tp->snd_una;
2538         tcp_free_sackholes(tp);
2539         tp->snd_recover = tp->snd_max;
2540         if (tp->t_flags & TF_SACK_PERMIT)
2541                 EXIT_FASTRECOVERY(tp->t_flags);
2542         tp->t_fb->tfb_tcp_output(tp);
2543 }
2544
2545 #ifdef INET
2546 /*
2547  * Look-up the routing entry to the peer of this inpcb.  If no route
2548  * is found and it cannot be allocated, then return 0.  This routine
2549  * is called by TCP routines that access the rmx structure and by
2550  * tcp_mss_update to get the peer/interface MTU.
2551  */
2552 uint32_t
2553 tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
2554 {
2555         struct nhop4_extended nh4;
2556         struct ifnet *ifp;
2557         uint32_t maxmtu = 0;
2558
2559         KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
2560
2561         if (inc->inc_faddr.s_addr != INADDR_ANY) {
2562
2563                 if (fib4_lookup_nh_ext(inc->inc_fibnum, inc->inc_faddr,
2564                     NHR_REF, 0, &nh4) != 0)
2565                         return (0);
2566
2567                 ifp = nh4.nh_ifp;
2568                 maxmtu = nh4.nh_mtu;
2569
2570                 /* Report additional interface capabilities. */
2571                 if (cap != NULL) {
2572                         if (ifp->if_capenable & IFCAP_TSO4 &&
2573                             ifp->if_hwassist & CSUM_TSO) {
2574                                 cap->ifcap |= CSUM_TSO;
2575                                 cap->tsomax = ifp->if_hw_tsomax;
2576                                 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2577                                 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2578                         }
2579                 }
2580                 fib4_free_nh_ext(inc->inc_fibnum, &nh4);
2581         }
2582         return (maxmtu);
2583 }
2584 #endif /* INET */
2585
2586 #ifdef INET6
2587 uint32_t
2588 tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
2589 {
2590         struct nhop6_extended nh6;
2591         struct in6_addr dst6;
2592         uint32_t scopeid;
2593         struct ifnet *ifp;
2594         uint32_t maxmtu = 0;
2595
2596         KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
2597
2598         if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
2599                 in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
2600                 if (fib6_lookup_nh_ext(inc->inc_fibnum, &dst6, scopeid, 0,
2601                     0, &nh6) != 0)
2602                         return (0);
2603
2604                 ifp = nh6.nh_ifp;
2605                 maxmtu = nh6.nh_mtu;
2606
2607                 /* Report additional interface capabilities. */
2608                 if (cap != NULL) {
2609                         if (ifp->if_capenable & IFCAP_TSO6 &&
2610                             ifp->if_hwassist & CSUM_TSO) {
2611                                 cap->ifcap |= CSUM_TSO;
2612                                 cap->tsomax = ifp->if_hw_tsomax;
2613                                 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2614                                 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2615                         }
2616                 }
2617                 fib6_free_nh_ext(inc->inc_fibnum, &nh6);
2618         }
2619
2620         return (maxmtu);
2621 }
2622 #endif /* INET6 */
2623
2624 /*
2625  * Calculate effective SMSS per RFC5681 definition for a given TCP
2626  * connection at its current state, taking into account SACK and etc.
2627  */
2628 u_int
2629 tcp_maxseg(const struct tcpcb *tp)
2630 {
2631         u_int optlen;
2632
2633         if (tp->t_flags & TF_NOOPT)
2634                 return (tp->t_maxseg);
2635
2636         /*
2637          * Here we have a simplified code from tcp_addoptions(),
2638          * without a proper loop, and having most of paddings hardcoded.
2639          * We might make mistakes with padding here in some edge cases,
2640          * but this is harmless, since result of tcp_maxseg() is used
2641          * only in cwnd and ssthresh estimations.
2642          */
2643 #define PAD(len)        ((((len) / 4) + !!((len) % 4)) * 4)
2644         if (TCPS_HAVEESTABLISHED(tp->t_state)) {
2645                 if (tp->t_flags & TF_RCVD_TSTMP)
2646                         optlen = TCPOLEN_TSTAMP_APPA;
2647                 else
2648                         optlen = 0;
2649 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2650                 if (tp->t_flags & TF_SIGNATURE)
2651                         optlen += PAD(TCPOLEN_SIGNATURE);
2652 #endif
2653                 if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
2654                         optlen += TCPOLEN_SACKHDR;
2655                         optlen += tp->rcv_numsacks * TCPOLEN_SACK;
2656                         optlen = PAD(optlen);
2657                 }
2658         } else {
2659                 if (tp->t_flags & TF_REQ_TSTMP)
2660                         optlen = TCPOLEN_TSTAMP_APPA;
2661                 else
2662                         optlen = PAD(TCPOLEN_MAXSEG);
2663                 if (tp->t_flags & TF_REQ_SCALE)
2664                         optlen += PAD(TCPOLEN_WINDOW);
2665 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2666                 if (tp->t_flags & TF_SIGNATURE)
2667                         optlen += PAD(TCPOLEN_SIGNATURE);
2668 #endif
2669                 if (tp->t_flags & TF_SACK_PERMIT)
2670                         optlen += PAD(TCPOLEN_SACK_PERMITTED);
2671         }
2672 #undef PAD
2673         optlen = min(optlen, TCP_MAXOLEN);
2674         return (tp->t_maxseg - optlen);
2675 }
2676
2677 static int
2678 sysctl_drop(SYSCTL_HANDLER_ARGS)
2679 {
2680         /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2681         struct sockaddr_storage addrs[2];
2682         struct inpcb *inp;
2683         struct tcpcb *tp;
2684         struct tcptw *tw;
2685         struct sockaddr_in *fin, *lin;
2686 #ifdef INET6
2687         struct sockaddr_in6 *fin6, *lin6;
2688 #endif
2689         int error;
2690
2691         inp = NULL;
2692         fin = lin = NULL;
2693 #ifdef INET6
2694         fin6 = lin6 = NULL;
2695 #endif
2696         error = 0;
2697
2698         if (req->oldptr != NULL || req->oldlen != 0)
2699                 return (EINVAL);
2700         if (req->newptr == NULL)
2701                 return (EPERM);
2702         if (req->newlen < sizeof(addrs))
2703                 return (ENOMEM);
2704         error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2705         if (error)
2706                 return (error);
2707
2708         switch (addrs[0].ss_family) {
2709 #ifdef INET6
2710         case AF_INET6:
2711                 fin6 = (struct sockaddr_in6 *)&addrs[0];
2712                 lin6 = (struct sockaddr_in6 *)&addrs[1];
2713                 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2714                     lin6->sin6_len != sizeof(struct sockaddr_in6))
2715                         return (EINVAL);
2716                 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2717                         if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2718                                 return (EINVAL);
2719                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
2720                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
2721                         fin = (struct sockaddr_in *)&addrs[0];
2722                         lin = (struct sockaddr_in *)&addrs[1];
2723                         break;
2724                 }
2725                 error = sa6_embedscope(fin6, V_ip6_use_defzone);
2726                 if (error)
2727                         return (error);
2728                 error = sa6_embedscope(lin6, V_ip6_use_defzone);
2729                 if (error)
2730                         return (error);
2731                 break;
2732 #endif
2733 #ifdef INET
2734         case AF_INET:
2735                 fin = (struct sockaddr_in *)&addrs[0];
2736                 lin = (struct sockaddr_in *)&addrs[1];
2737                 if (fin->sin_len != sizeof(struct sockaddr_in) ||
2738                     lin->sin_len != sizeof(struct sockaddr_in))
2739                         return (EINVAL);
2740                 break;
2741 #endif
2742         default:
2743                 return (EINVAL);
2744         }
2745         INP_INFO_RLOCK(&V_tcbinfo);
2746         switch (addrs[0].ss_family) {
2747 #ifdef INET6
2748         case AF_INET6:
2749                 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
2750                     fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
2751                     INPLOOKUP_WLOCKPCB, NULL);
2752                 break;
2753 #endif
2754 #ifdef INET
2755         case AF_INET:
2756                 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
2757                     lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
2758                 break;
2759 #endif
2760         }
2761         if (inp != NULL) {
2762                 if (inp->inp_flags & INP_TIMEWAIT) {
2763                         /*
2764                          * XXXRW: There currently exists a state where an
2765                          * inpcb is present, but its timewait state has been
2766                          * discarded.  For now, don't allow dropping of this
2767                          * type of inpcb.
2768                          */
2769                         tw = intotw(inp);
2770                         if (tw != NULL)
2771                                 tcp_twclose(tw, 0);
2772                         else
2773                                 INP_WUNLOCK(inp);
2774                 } else if (!(inp->inp_flags & INP_DROPPED) &&
2775                            !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
2776                         tp = intotcpcb(inp);
2777                         tp = tcp_drop(tp, ECONNABORTED);
2778                         if (tp != NULL)
2779                                 INP_WUNLOCK(inp);
2780                 } else
2781                         INP_WUNLOCK(inp);
2782         } else
2783                 error = ESRCH;
2784         INP_INFO_RUNLOCK(&V_tcbinfo);
2785         return (error);
2786 }
2787
2788 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
2789     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP, NULL,
2790     0, sysctl_drop, "", "Drop TCP connection");
2791
2792 /*
2793  * Generate a standardized TCP log line for use throughout the
2794  * tcp subsystem.  Memory allocation is done with M_NOWAIT to
2795  * allow use in the interrupt context.
2796  *
2797  * NB: The caller MUST free(s, M_TCPLOG) the returned string.
2798  * NB: The function may return NULL if memory allocation failed.
2799  *
2800  * Due to header inclusion and ordering limitations the struct ip
2801  * and ip6_hdr pointers have to be passed as void pointers.
2802  */
2803 char *
2804 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2805     const void *ip6hdr)
2806 {
2807
2808         /* Is logging enabled? */
2809         if (tcp_log_in_vain == 0)
2810                 return (NULL);
2811
2812         return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2813 }
2814
2815 char *
2816 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2817     const void *ip6hdr)
2818 {
2819
2820         /* Is logging enabled? */
2821         if (tcp_log_debug == 0)
2822                 return (NULL);
2823
2824         return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2825 }
2826
2827 static char *
2828 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2829     const void *ip6hdr)
2830 {
2831         char *s, *sp;
2832         size_t size;
2833         struct ip *ip;
2834 #ifdef INET6
2835         const struct ip6_hdr *ip6;
2836
2837         ip6 = (const struct ip6_hdr *)ip6hdr;
2838 #endif /* INET6 */
2839         ip = (struct ip *)ip4hdr;
2840
2841         /*
2842          * The log line looks like this:
2843          * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
2844          */
2845         size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
2846             sizeof(PRINT_TH_FLAGS) + 1 +
2847 #ifdef INET6
2848             2 * INET6_ADDRSTRLEN;
2849 #else
2850             2 * INET_ADDRSTRLEN;
2851 #endif /* INET6 */
2852
2853         s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
2854         if (s == NULL)
2855                 return (NULL);
2856
2857         strcat(s, "TCP: [");
2858         sp = s + strlen(s);
2859
2860         if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
2861                 inet_ntoa_r(inc->inc_faddr, sp);
2862                 sp = s + strlen(s);
2863                 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2864                 sp = s + strlen(s);
2865                 inet_ntoa_r(inc->inc_laddr, sp);
2866                 sp = s + strlen(s);
2867                 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2868 #ifdef INET6
2869         } else if (inc) {
2870                 ip6_sprintf(sp, &inc->inc6_faddr);
2871                 sp = s + strlen(s);
2872                 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2873                 sp = s + strlen(s);
2874                 ip6_sprintf(sp, &inc->inc6_laddr);
2875                 sp = s + strlen(s);
2876                 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2877         } else if (ip6 && th) {
2878                 ip6_sprintf(sp, &ip6->ip6_src);
2879                 sp = s + strlen(s);
2880                 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2881                 sp = s + strlen(s);
2882                 ip6_sprintf(sp, &ip6->ip6_dst);
2883                 sp = s + strlen(s);
2884                 sprintf(sp, "]:%i", ntohs(th->th_dport));
2885 #endif /* INET6 */
2886 #ifdef INET
2887         } else if (ip && th) {
2888                 inet_ntoa_r(ip->ip_src, sp);
2889                 sp = s + strlen(s);
2890                 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2891                 sp = s + strlen(s);
2892                 inet_ntoa_r(ip->ip_dst, sp);
2893                 sp = s + strlen(s);
2894                 sprintf(sp, "]:%i", ntohs(th->th_dport));
2895 #endif /* INET */
2896         } else {
2897                 free(s, M_TCPLOG);
2898                 return (NULL);
2899         }
2900         sp = s + strlen(s);
2901         if (th)
2902                 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
2903         if (*(s + size - 1) != '\0')
2904                 panic("%s: string too long", __func__);
2905         return (s);
2906 }
2907
2908 /*
2909  * A subroutine which makes it easy to track TCP state changes with DTrace.
2910  * This function shouldn't be called for t_state initializations that don't
2911  * correspond to actual TCP state transitions.
2912  */
2913 void
2914 tcp_state_change(struct tcpcb *tp, int newstate)
2915 {
2916 #if defined(KDTRACE_HOOKS)
2917         int pstate = tp->t_state;
2918 #endif
2919
2920         TCPSTATES_DEC(tp->t_state);
2921         TCPSTATES_INC(newstate);
2922         tp->t_state = newstate;
2923         TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
2924 }
2925
2926 /*
2927  * Create an external-format (``xtcpcb'') structure using the information in
2928  * the kernel-format tcpcb structure pointed to by tp.  This is done to
2929  * reduce the spew of irrelevant information over this interface, to isolate
2930  * user code from changes in the kernel structure, and potentially to provide
2931  * information-hiding if we decide that some of this information should be
2932  * hidden from users.
2933  */
2934 void
2935 tcp_inptoxtp(const struct inpcb *inp, struct xtcpcb *xt)
2936 {
2937         struct tcpcb *tp = intotcpcb(inp);
2938         sbintime_t now;
2939
2940         if (inp->inp_flags & INP_TIMEWAIT) {
2941                 bzero(xt, sizeof(struct xtcpcb));
2942                 xt->t_state = TCPS_TIME_WAIT;
2943         } else {
2944                 xt->t_state = tp->t_state;
2945                 xt->t_logstate = tp->t_logstate;
2946                 xt->t_flags = tp->t_flags;
2947                 xt->t_sndzerowin = tp->t_sndzerowin;
2948                 xt->t_sndrexmitpack = tp->t_sndrexmitpack;
2949                 xt->t_rcvoopack = tp->t_rcvoopack;
2950
2951                 now = getsbinuptime();
2952 #define COPYTIMER(ttt)  do {                                            \
2953                 if (callout_active(&tp->t_timers->ttt))                 \
2954                         xt->ttt = (tp->t_timers->ttt.c_time - now) /    \
2955                             SBT_1MS;                                    \
2956                 else                                                    \
2957                         xt->ttt = 0;                                    \
2958 } while (0)
2959                 COPYTIMER(tt_delack);
2960                 COPYTIMER(tt_rexmt);
2961                 COPYTIMER(tt_persist);
2962                 COPYTIMER(tt_keep);
2963                 COPYTIMER(tt_2msl);
2964 #undef COPYTIMER
2965                 xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
2966
2967                 bcopy(tp->t_fb->tfb_tcp_block_name, xt->xt_stack,
2968                     TCP_FUNCTION_NAME_LEN_MAX);
2969                 bzero(xt->xt_logid, TCP_LOG_ID_LEN);
2970 #ifdef TCP_BLACKBOX
2971                 (void)tcp_log_get_id(tp, xt->xt_logid);
2972 #endif
2973         }
2974
2975         xt->xt_len = sizeof(struct xtcpcb);
2976         in_pcbtoxinpcb(inp, &xt->xt_inp);
2977         if (inp->inp_socket == NULL)
2978                 xt->xt_inp.xi_socket.xso_protocol = IPPROTO_TCP;
2979 }