The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_reass.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 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_input.c 8.12 (Berkeley) 5/24/95
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD: releng/12.0/sys/netinet/tcp_reass.c 342894 2019-01-09 18:42:40Z emaste $");
   36 
   37 #include "opt_inet.h"
   38 #include "opt_inet6.h"
   39 #include "opt_tcpdebug.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/kernel.h>
   43 #include <sys/eventhandler.h>
   44 #include <sys/malloc.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/socket.h>
   47 #include <sys/socketvar.h>
   48 #include <sys/sysctl.h>
   49 #include <sys/syslog.h>
   50 #include <sys/systm.h>
   51 
   52 #include <vm/uma.h>
   53 
   54 #include <net/if.h>
   55 #include <net/if_var.h>
   56 #include <net/route.h>
   57 #include <net/vnet.h>
   58 
   59 #include <netinet/in.h>
   60 #include <netinet/in_pcb.h>
   61 #include <netinet/in_systm.h>
   62 #include <netinet/in_var.h>
   63 #include <netinet/ip.h>
   64 #include <netinet/ip_var.h>
   65 #include <netinet/ip_options.h>
   66 #include <netinet/ip6.h>
   67 #include <netinet6/in6_pcb.h>
   68 #include <netinet6/ip6_var.h>
   69 #include <netinet6/nd6.h>
   70 #include <netinet/tcp.h>
   71 #include <netinet/tcp_fsm.h>
   72 #include <netinet/tcp_seq.h>
   73 #include <netinet/tcp_timer.h>
   74 #include <netinet/tcp_var.h>
   75 #include <netinet/tcp_log_buf.h>
   76 #include <netinet/tcp_hpts.h>
   77 #include <netinet6/tcp6_var.h>
   78 #include <netinet/tcpip.h>
   79 #ifdef TCPDEBUG
   80 #include <netinet/tcp_debug.h>
   81 #endif /* TCPDEBUG */
   82 
   83 #define TCP_R_LOG_ADD           1
   84 #define TCP_R_LOG_LIMIT_REACHED 2
   85 #define TCP_R_LOG_APPEND        3
   86 #define TCP_R_LOG_PREPEND       4
   87 #define TCP_R_LOG_REPLACE       5
   88 #define TCP_R_LOG_MERGE_INTO    6
   89 #define TCP_R_LOG_NEW_ENTRY     7
   90 #define TCP_R_LOG_READ          8
   91 #define TCP_R_LOG_ZERO          9
   92 #define TCP_R_LOG_DUMP          10
   93 #define TCP_R_LOG_TRIM          11
   94 
   95 /* For debugging we want counters and BB logging */
   96 /* #define TCP_REASS_COUNTERS 1 */
   97 /* #define TCP_REASS_LOGGING 1 */
   98 
   99 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0,
  100     "TCP Segment Reassembly Queue");
  101 
  102 static SYSCTL_NODE(_net_inet_tcp_reass, OID_AUTO, stats, CTLFLAG_RW, 0,
  103     "TCP Segment Reassembly stats");
  104 
  105 
  106 static int tcp_reass_maxseg = 0;
  107 SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RDTUN,
  108     &tcp_reass_maxseg, 0,
  109     "Global maximum number of TCP Segments in Reassembly Queue");
  110 
  111 static uma_zone_t tcp_reass_zone;
  112 SYSCTL_UMA_CUR(_net_inet_tcp_reass, OID_AUTO, cursegments, 0,
  113     &tcp_reass_zone,
  114     "Global number of TCP Segments currently in Reassembly Queue");
  115 
  116 static u_int tcp_reass_maxqueuelen = 100;
  117 SYSCTL_UINT(_net_inet_tcp_reass, OID_AUTO, maxqueuelen, CTLFLAG_RWTUN,
  118     &tcp_reass_maxqueuelen, 0,
  119     "Maximum number of TCP Segments per Reassembly Queue");
  120 
  121 static int tcp_new_limits = 0;
  122 SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, new_limit, CTLFLAG_RWTUN,
  123     &tcp_new_limits, 0,
  124     "Do we use the new limit method we are discussing?");
  125 
  126 static u_int tcp_reass_queue_guard = 16;
  127 SYSCTL_UINT(_net_inet_tcp_reass, OID_AUTO, queueguard, CTLFLAG_RWTUN,
  128     &tcp_reass_queue_guard, 16,
  129     "Number of TCP Segments in Reassembly Queue where we flip over to guard mode");
  130 
  131 #ifdef TCP_REASS_COUNTERS
  132 
  133 counter_u64_t reass_entry;
  134 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, entry, CTLFLAG_RD,
  135     &reass_entry, "A segment entered reassembly ");
  136 
  137 counter_u64_t reass_path1;
  138 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path1, CTLFLAG_RD,
  139     &reass_path1, "Took path 1");
  140 
  141 counter_u64_t reass_path2;
  142 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path2, CTLFLAG_RD,
  143     &reass_path2, "Took path 2");
  144 
  145 counter_u64_t reass_path3;
  146 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path3, CTLFLAG_RD,
  147     &reass_path3, "Took path 3");
  148 
  149 counter_u64_t reass_path4;
  150 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path4, CTLFLAG_RD,
  151     &reass_path4, "Took path 4");
  152 
  153 counter_u64_t reass_path5;
  154 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path5, CTLFLAG_RD,
  155     &reass_path5, "Took path 5");
  156 
  157 counter_u64_t reass_path6;
  158 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path6, CTLFLAG_RD,
  159     &reass_path6, "Took path 6");
  160 
  161 counter_u64_t reass_path7;
  162 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, path7, CTLFLAG_RD,
  163     &reass_path7, "Took path 7");
  164 
  165 counter_u64_t reass_fullwalk;
  166 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, fullwalk, CTLFLAG_RD,
  167     &reass_fullwalk, "Took a full walk ");
  168 
  169 counter_u64_t reass_nospace;
  170 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, nospace, CTLFLAG_RD,
  171     &reass_nospace, "Had no mbuf capacity ");
  172 
  173 counter_u64_t merge_fwd;
  174 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, merge_fwd, CTLFLAG_RD,
  175     &merge_fwd, "Ran merge fwd");
  176 
  177 counter_u64_t merge_into;
  178 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, merge_into, CTLFLAG_RD,
  179     &merge_into, "Ran merge into");
  180 
  181 counter_u64_t tcp_zero_input;
  182 SYSCTL_COUNTER_U64(_net_inet_tcp_reass_stats, OID_AUTO, zero_input, CTLFLAG_RD,
  183     &tcp_zero_input, "The reassembly buffer saw a zero len segment etc");
  184 
  185 #endif
  186 
  187 /* Initialize TCP reassembly queue */
  188 static void
  189 tcp_reass_zone_change(void *tag)
  190 {
  191 
  192         /* Set the zone limit and read back the effective value. */
  193         tcp_reass_maxseg = nmbclusters / 16;
  194         tcp_reass_maxseg = uma_zone_set_max(tcp_reass_zone,
  195             tcp_reass_maxseg);
  196 }
  197 
  198 #ifdef TCP_REASS_LOGGING
  199 
  200 static void
  201 tcp_log_reassm(struct tcpcb *tp, struct tseg_qent *q, struct tseg_qent *p,
  202     tcp_seq seq, int len, uint8_t action, int instance)
  203 {
  204         uint32_t cts;
  205         struct timeval tv;
  206 
  207         if (tp->t_logstate != TCP_LOG_STATE_OFF) {
  208                 union tcp_log_stackspecific log;
  209 
  210                 memset(&log, 0, sizeof(log));
  211                 cts = tcp_get_usecs(&tv);
  212                 log.u_bbr.flex1 = seq;
  213                 log.u_bbr.cur_del_rate = (uint64_t)q;
  214                 log.u_bbr.delRate = (uint64_t)p;
  215                 if (q != NULL) {
  216                         log.u_bbr.flex2 = q->tqe_start;
  217                         log.u_bbr.flex3 = q->tqe_len;
  218                         log.u_bbr.flex4 = q->tqe_mbuf_cnt;
  219                         log.u_bbr.hptsi_gain = q->tqe_flags;
  220                 }
  221                 if (p != NULL)  {
  222                         log.u_bbr.flex5 = p->tqe_start;
  223                         log.u_bbr.pkts_out = p->tqe_len;
  224                         log.u_bbr.epoch = p->tqe_mbuf_cnt;
  225                         log.u_bbr.cwnd_gain = p->tqe_flags;
  226                 }
  227                 log.u_bbr.flex6 = tp->t_segqmbuflen;
  228                 log.u_bbr.flex7 = instance;
  229                 log.u_bbr.flex8 = action;
  230                 log.u_bbr.timeStamp = cts;
  231                 TCP_LOG_EVENTP(tp, NULL,
  232                     &tp->t_inpcb->inp_socket->so_rcv,
  233                     &tp->t_inpcb->inp_socket->so_snd,
  234                     TCP_LOG_REASS, 0,
  235                     len, &log, false, &tv);
  236         }
  237 }
  238 
  239 static void
  240 tcp_reass_log_dump(struct tcpcb *tp)
  241 {
  242         struct tseg_qent *q;
  243 
  244         if (tp->t_logstate != TCP_LOG_STATE_OFF) {
  245                 TAILQ_FOREACH(q, &tp->t_segq, tqe_q) {
  246                         tcp_log_reassm(tp, q, NULL, q->tqe_start, q->tqe_len, TCP_R_LOG_DUMP, 0);
  247                 }
  248         };
  249 }
  250 
  251 static void
  252 tcp_reass_log_new_in(struct tcpcb *tp, tcp_seq seq, int len, struct mbuf *m,
  253     int logval, struct tseg_qent *q)
  254 {
  255         int cnt;
  256         struct mbuf *t;
  257 
  258         cnt = 0;
  259         t = m;
  260         while (t) {
  261                 cnt += t->m_len;
  262                 t = t->m_next;
  263         }
  264         tcp_log_reassm(tp, q, NULL, seq, len, logval, cnt);
  265 }
  266 
  267 #endif
  268 
  269 void
  270 tcp_reass_global_init(void)
  271 {
  272 
  273         tcp_reass_maxseg = nmbclusters / 16;
  274         TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments",
  275             &tcp_reass_maxseg);
  276         tcp_reass_zone = uma_zcreate("tcpreass", sizeof (struct tseg_qent),
  277             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  278         /* Set the zone limit and read back the effective value. */
  279         tcp_reass_maxseg = uma_zone_set_max(tcp_reass_zone,
  280             tcp_reass_maxseg);
  281 #ifdef TCP_REASS_COUNTERS
  282         reass_path1 = counter_u64_alloc(M_WAITOK);
  283         reass_path2 = counter_u64_alloc(M_WAITOK);
  284         reass_path3 = counter_u64_alloc(M_WAITOK);
  285         reass_path4 = counter_u64_alloc(M_WAITOK);
  286         reass_path5 = counter_u64_alloc(M_WAITOK);
  287         reass_path6 = counter_u64_alloc(M_WAITOK);
  288         reass_path7 = counter_u64_alloc(M_WAITOK);
  289         reass_fullwalk = counter_u64_alloc(M_WAITOK);
  290         reass_nospace = counter_u64_alloc(M_WAITOK);
  291         reass_entry = counter_u64_alloc(M_WAITOK);
  292         merge_fwd = counter_u64_alloc(M_WAITOK);
  293         merge_into = counter_u64_alloc(M_WAITOK);
  294         tcp_zero_input = counter_u64_alloc(M_WAITOK);
  295 #endif
  296         EVENTHANDLER_REGISTER(nmbclusters_change,
  297             tcp_reass_zone_change, NULL, EVENTHANDLER_PRI_ANY);
  298 
  299 }
  300 
  301 void
  302 tcp_reass_flush(struct tcpcb *tp)
  303 {
  304         struct tseg_qent *qe;
  305 
  306         INP_WLOCK_ASSERT(tp->t_inpcb);
  307 
  308         while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) {
  309                 TAILQ_REMOVE(&tp->t_segq, qe, tqe_q);
  310                 m_freem(qe->tqe_m);
  311                 uma_zfree(tcp_reass_zone, qe);
  312                 tp->t_segqlen--;
  313         }
  314         tp->t_segqmbuflen = 0;
  315         KASSERT((tp->t_segqlen == 0),
  316             ("TCP reass queue %p segment count is %d instead of 0 after flush.",
  317             tp, tp->t_segqlen));
  318 }
  319 
  320 static void
  321 tcp_reass_append(struct tcpcb *tp, struct tseg_qent *last,
  322     struct mbuf *m, struct tcphdr *th, int tlen, 
  323     struct mbuf *mlast, int lenofoh)
  324 {
  325 
  326 #ifdef TCP_REASS_LOGGING
  327         tcp_log_reassm(tp, last, NULL, th->th_seq, tlen, TCP_R_LOG_APPEND, 0);
  328 #endif
  329         last->tqe_len += tlen;
  330         last->tqe_m->m_pkthdr.len += tlen;
  331         /* Preserve the FIN bit if its there */
  332         last->tqe_flags |= (th->th_flags & TH_FIN);
  333         last->tqe_last->m_next = m;
  334         last->tqe_last = mlast;
  335         last->tqe_mbuf_cnt += lenofoh;
  336         tp->t_rcvoopack++;
  337         TCPSTAT_INC(tcps_rcvoopack);
  338         TCPSTAT_ADD(tcps_rcvoobyte, tlen);
  339 #ifdef TCP_REASS_LOGGING
  340         tcp_reass_log_new_in(tp, last->tqe_start, lenofoh, last->tqe_m,
  341                              TCP_R_LOG_APPEND,
  342                              last);
  343 #endif
  344 }
  345 
  346 static void
  347 tcp_reass_prepend(struct tcpcb *tp, struct tseg_qent *first, struct mbuf *m, struct tcphdr *th,
  348                   int tlen, struct mbuf *mlast, int lenofoh)
  349 {
  350         int i;
  351         
  352 #ifdef TCP_REASS_LOGGING
  353         tcp_log_reassm(tp, first, NULL, th->th_seq, tlen, TCP_R_LOG_PREPEND, 0);
  354 #endif
  355         if (SEQ_GT((th->th_seq + tlen), first->tqe_start)) {
  356                 /* The new data overlaps into the old */
  357                 i = (th->th_seq + tlen) - first->tqe_start;
  358 #ifdef TCP_REASS_LOGGING
  359                 tcp_log_reassm(tp, first, NULL, 0, i, TCP_R_LOG_TRIM, 1);
  360 #endif
  361                 m_adj(first->tqe_m, i);
  362                 first->tqe_len -= i;
  363                 first->tqe_start += i;
  364         }
  365         /* Ok now setup our chain to point to the old first */
  366         mlast->m_next = first->tqe_m;
  367         first->tqe_m = m;
  368         first->tqe_len += tlen;
  369         first->tqe_start = th->th_seq;
  370         first->tqe_m->m_pkthdr.len = first->tqe_len;
  371         first->tqe_mbuf_cnt += lenofoh;
  372         tp->t_rcvoopack++;
  373         TCPSTAT_INC(tcps_rcvoopack);
  374         TCPSTAT_ADD(tcps_rcvoobyte, tlen);
  375 #ifdef TCP_REASS_LOGGING
  376         tcp_reass_log_new_in(tp, first->tqe_start, lenofoh, first->tqe_m,
  377                              TCP_R_LOG_PREPEND,
  378                              first);
  379 #endif
  380 }
  381 
  382 static void 
  383 tcp_reass_replace(struct tcpcb *tp, struct tseg_qent *q, struct mbuf *m,
  384     tcp_seq seq, int len, struct mbuf *mlast, int mbufoh, uint8_t flags)
  385 {
  386         /*
  387          * Free the data in q, and replace
  388          * it with the new segment.
  389          */
  390         int len_dif;
  391 
  392 #ifdef TCP_REASS_LOGGING
  393         tcp_log_reassm(tp, q, NULL, seq, len, TCP_R_LOG_REPLACE, 0);
  394 #endif
  395         m_freem(q->tqe_m);
  396         KASSERT(tp->t_segqmbuflen >= q->tqe_mbuf_cnt,
  397                 ("Tp:%p seg queue goes negative", tp));
  398         tp->t_segqmbuflen -= q->tqe_mbuf_cnt;                  
  399         q->tqe_mbuf_cnt = mbufoh;
  400         q->tqe_m = m;
  401         q->tqe_last = mlast;
  402         q->tqe_start = seq;
  403         if (len > q->tqe_len)
  404                 len_dif = len - q->tqe_len;
  405         else
  406                 len_dif = 0;
  407         tp->t_rcvoopack++;
  408         TCPSTAT_INC(tcps_rcvoopack);
  409         TCPSTAT_ADD(tcps_rcvoobyte, len_dif);
  410         q->tqe_len = len;
  411         q->tqe_flags = (flags & TH_FIN);
  412         q->tqe_m->m_pkthdr.len = q->tqe_len;
  413         tp->t_segqmbuflen += mbufoh;
  414 
  415 }
  416 
  417 static void
  418 tcp_reass_merge_into(struct tcpcb *tp, struct tseg_qent *ent,
  419     struct tseg_qent *q)
  420 {
  421         /* 
  422          * Merge q into ent and free q from the list.
  423          */
  424 #ifdef TCP_REASS_LOGGING
  425         tcp_log_reassm(tp, q, ent, 0, 0, TCP_R_LOG_MERGE_INTO, 0);
  426 #endif
  427 #ifdef TCP_REASS_COUNTERS
  428         counter_u64_add(merge_into, 1);
  429 #endif
  430         ent->tqe_last->m_next = q->tqe_m;
  431         ent->tqe_last = q->tqe_last;
  432         ent->tqe_len += q->tqe_len;
  433         ent->tqe_mbuf_cnt += q->tqe_mbuf_cnt;
  434         ent->tqe_m->m_pkthdr.len += q->tqe_len;
  435         ent->tqe_flags |= (q->tqe_flags & TH_FIN);
  436         TAILQ_REMOVE(&tp->t_segq, q, tqe_q);
  437         uma_zfree(tcp_reass_zone, q);
  438         tp->t_segqlen--;
  439 
  440 }
  441 
  442 static void
  443 tcp_reass_merge_forward(struct tcpcb *tp, struct tseg_qent *ent)
  444 {
  445         struct tseg_qent *q, *qtmp;
  446         int i;
  447         tcp_seq max;
  448         /*
  449          * Given an entry merge forward anyplace
  450          * that ent overlaps forward.
  451          */
  452 
  453         max = ent->tqe_start + ent->tqe_len;
  454         q = TAILQ_NEXT(ent, tqe_q);
  455         if (q == NULL) {
  456                 /* Nothing left */
  457                 return;
  458         }
  459         TAILQ_FOREACH_FROM_SAFE(q, &tp->t_segq, tqe_q, qtmp) {
  460                 if (SEQ_GT(q->tqe_start, max)) {
  461                         /* Beyond q */
  462                         break;
  463                 }
  464                 /* We have some or all that are overlapping */
  465                 if (SEQ_GEQ(max, (q->tqe_start + q->tqe_len))) {
  466                         /* It consumes it all */
  467                         tp->t_segqmbuflen -= q->tqe_mbuf_cnt;
  468                         m_freem(q->tqe_m);
  469                         TAILQ_REMOVE(&tp->t_segq, q, tqe_q);
  470                         uma_zfree(tcp_reass_zone, q);
  471                         tp->t_segqlen--;
  472                         continue;
  473                 }
  474                 /* 
  475                  * Trim the q entry to dovetail to this one 
  476                  * and then merge q into ent updating max
  477                  * in the process.
  478                  */
  479                 i = max - q->tqe_start;
  480 #ifdef TCP_REASS_LOGGING
  481                 tcp_log_reassm(tp, q, NULL, 0, i, TCP_R_LOG_TRIM, 2);
  482 #endif
  483                 m_adj(q->tqe_m, i);
  484                 q->tqe_len -= i;
  485                 q->tqe_start += i;
  486                 tcp_reass_merge_into(tp, ent, q);
  487                 max = ent->tqe_start + ent->tqe_len;
  488         }
  489 #ifdef TCP_REASS_COUNTERS
  490         counter_u64_add(merge_fwd, 1);
  491 #endif
  492 }
  493 
  494 static int 
  495 tcp_reass_overhead_of_chain(struct mbuf *m, struct mbuf **mlast)
  496 {
  497         int len = MSIZE;
  498 
  499         if (m->m_flags & M_EXT)
  500                 len += m->m_ext.ext_size;
  501         while (m->m_next != NULL) {
  502                 m = m->m_next;
  503                 len += MSIZE;
  504                 if (m->m_flags & M_EXT)
  505                         len += m->m_ext.ext_size;
  506         }
  507         *mlast = m;
  508         return (len);
  509 }
  510 
  511 
  512 /*
  513  * NOTE!!! the new tcp-reassembly code *must not* use
  514  * m_adj() with a negative index. That alters the chain
  515  * of mbufs (by possibly chopping trailing mbufs). At
  516  * the front of tcp_reass we count the mbuf overhead
  517  * and setup the tail pointer. If we use m_adj(m, -5)
  518  * we could corrupt the tail pointer. Currently the
  519  * code only uses m_adj(m, postive-num). If this
  520  * changes appropriate changes to update mlast would
  521  * be needed.
  522  */
  523 int
  524 tcp_reass(struct tcpcb *tp, struct tcphdr *th, tcp_seq *seq_start,
  525           int *tlenp, struct mbuf *m)
  526 {
  527         struct tseg_qent *q, *last, *first;
  528         struct tseg_qent *p = NULL;
  529         struct tseg_qent *nq = NULL;
  530         struct tseg_qent *te = NULL;
  531         struct mbuf *mlast = NULL;
  532         struct sockbuf *sb;
  533         struct socket *so = tp->t_inpcb->inp_socket;
  534         char *s = NULL;
  535         int flags, i, lenofoh;
  536 
  537         INP_WLOCK_ASSERT(tp->t_inpcb);
  538         /*
  539          * XXX: tcp_reass() is rather inefficient with its data structures
  540          * and should be rewritten (see NetBSD for optimizations).
  541          */
  542 
  543         /*
  544          * Call with th==NULL after become established to
  545          * force pre-ESTABLISHED data up to user socket.
  546          */
  547         if (th == NULL)
  548                 goto present;
  549         KASSERT(SEQ_GEQ(th->th_seq, tp->rcv_nxt),
  550                 ("Attempt to add old entry to reassembly queue (th=%p, tp=%p)",
  551                  th, tp));
  552 #ifdef TCP_REASS_LOGGING
  553         tcp_reass_log_new_in(tp, th->th_seq, *tlenp, m, TCP_R_LOG_ADD, NULL);
  554 #endif
  555 #ifdef TCP_REASS_COUNTERS
  556         counter_u64_add(reass_entry, 1);
  557 #endif
  558         /*
  559          * Check for zero length data.
  560          */
  561         if ((*tlenp == 0) && ((th->th_flags & TH_FIN) == 0)) {
  562                 /*
  563                  * A zero length segment does no
  564                  * one any good. We could check
  565                  * the rcv_nxt <-> rcv_wnd but thats
  566                  * already done for us by the caller.
  567                  */
  568 #ifdef TCP_REASS_COUNTERS 
  569                 counter_u64_add(tcp_zero_input, 1);
  570 #endif
  571                 m_freem(m);
  572 #ifdef TCP_REASS_LOGGING
  573                 tcp_reass_log_dump(tp);
  574 #endif
  575                 return (0);
  576         }
  577         /*
  578          * Will it fit?
  579          */
  580         lenofoh = tcp_reass_overhead_of_chain(m, &mlast);
  581         sb = &tp->t_inpcb->inp_socket->so_rcv;
  582         if ((th->th_seq != tp->rcv_nxt || !TCPS_HAVEESTABLISHED(tp->t_state)) &&
  583             (sb->sb_mbcnt + tp->t_segqmbuflen + lenofoh) > sb->sb_mbmax) {
  584                 /* No room */
  585                 TCPSTAT_INC(tcps_rcvreassfull);
  586 #ifdef TCP_REASS_COUNTERS
  587                 counter_u64_add(reass_nospace, 1);
  588 #endif
  589 #ifdef TCP_REASS_LOGGING
  590                 tcp_log_reassm(tp, NULL, NULL, th->th_seq, lenofoh, TCP_R_LOG_LIMIT_REACHED, 0);
  591 #endif
  592                 if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) {
  593                         log(LOG_DEBUG, "%s; %s: mbuf count limit reached, "
  594                             "segment dropped\n", s, __func__);
  595                         free(s, M_TCPLOG);
  596                 }
  597                 m_freem(m);
  598                 *tlenp = 0;
  599 #ifdef TCP_REASS_LOGGING
  600                 tcp_reass_log_dump(tp);
  601 #endif
  602                 return (0);
  603         }
  604         /*
  605          * First lets deal with two common cases, the
  606          * segment appends to the back of our collected
  607          * segments. Or the segment is the next in line.
  608          */
  609         last = TAILQ_LAST_FAST(&tp->t_segq, tseg_qent, tqe_q);
  610         if (last != NULL) {
  611                 if ((th->th_flags & TH_FIN) &&
  612                     SEQ_LT((th->th_seq + *tlenp), (last->tqe_start + last->tqe_len))) {
  613                         /* 
  614                          * Someone is trying to game us, dump
  615                          * the segment.
  616                          */
  617                         *tlenp = 0;
  618                         m_freem(m);
  619                         return (0);
  620                 }
  621                 if ((SEQ_GEQ(th->th_seq, last->tqe_start)) &&
  622                     (SEQ_GEQ((last->tqe_start + last->tqe_len), th->th_seq))) {
  623                         /* Common case, trailing segment is added */
  624                         /**
  625                          *                                 +--last
  626                          *                                 v
  627                          *  reassembly buffer |---|  |---| |---|
  628                          *  new segment                       |---|
  629                          */
  630 #ifdef TCP_REASS_COUNTERS
  631                         counter_u64_add(reass_path1, 1);
  632 #endif
  633                         if (SEQ_GT((last->tqe_start + last->tqe_len), th->th_seq)) {
  634                                 i = (last->tqe_start + last->tqe_len) - th->th_seq;
  635                                 if (i < *tlenp) {
  636 #ifdef TCP_REASS_LOGGING
  637                                         tcp_log_reassm(tp, last, NULL, 0, i, TCP_R_LOG_TRIM, 3);
  638                                         th->th_seq += i;
  639 #endif
  640                                         m_adj(m, i);
  641                                         *tlenp -= i;
  642                                 } else {
  643                                         /* Complete overlap */
  644                                         TCPSTAT_INC(tcps_rcvduppack);
  645                                         TCPSTAT_ADD(tcps_rcvdupbyte, *tlenp);
  646                                         m_freem(m);
  647                                         *tlenp = last->tqe_len;
  648                                         *seq_start = last->tqe_start;
  649                                         return (0);
  650                                 }
  651                         }
  652                         if (last->tqe_flags & TH_FIN) {
  653                                 /* 
  654                                  * We have data after the FIN on the last? 
  655                                  */
  656                                 *tlenp = 0;
  657                                 m_freem(m);
  658                                 return(0);
  659                         }
  660                         tcp_reass_append(tp, last, m, th, *tlenp, mlast, lenofoh);
  661                         tp->t_segqmbuflen += lenofoh;
  662                         *seq_start = last->tqe_start;
  663                         *tlenp = last->tqe_len;
  664                         return (0);
  665                 } else if (SEQ_GT(th->th_seq, (last->tqe_start + last->tqe_len))) {
  666                         /* 
  667                          * Second common case, we missed
  668                          * another one and have something more
  669                          * for the end.
  670                          */
  671                         /**
  672                          *                                 +--last
  673                          *                                 v
  674                          *  reassembly buffer |---|  |---| |---|
  675                          *  new segment                           |---|
  676                          */
  677                         if (last->tqe_flags & TH_FIN) {
  678                                 /* 
  679                                  * We have data after the FIN on the last? 
  680                                  */
  681                                 *tlenp = 0;
  682                                 m_freem(m);
  683                                 return(0);
  684                         }
  685 #ifdef TCP_REASS_COUNTERS
  686                         counter_u64_add(reass_path2, 1);
  687 #endif
  688                         p = last;
  689                         goto new_entry;
  690                 }
  691         } else {
  692                 /* First segment (it's NULL). */
  693                 goto new_entry;
  694         }
  695         first = TAILQ_FIRST(&tp->t_segq);
  696         if (SEQ_LT(th->th_seq, first->tqe_start) &&
  697             SEQ_GEQ((th->th_seq + *tlenp),first->tqe_start) &&
  698             SEQ_LT((th->th_seq + *tlenp), (first->tqe_start + first->tqe_len))) {
  699                 /*
  700                  * The head of the queue is prepended by this and
  701                  * it may be the one I want most.
  702                  */
  703                 /**
  704                  *       first-------+
  705                  *                   v
  706                  *  rea:             |---|  |---| |---|
  707                  *  new:         |---|
  708                  * Note the case we do not deal with here is:
  709                  *   rea=     |---|   |---|   |---|
  710                  *   new=  |----|
  711                  * Due to the fact that it could be
  712                  *   new   |--------------------|
  713                  * And we might need to merge forward.
  714                  */
  715 #ifdef INVARIANTS
  716                 struct mbuf *firstmbuf;
  717 #endif
  718 
  719 #ifdef TCP_REASS_COUNTERS
  720                 counter_u64_add(reass_path3, 1);
  721 #endif
  722                 if (SEQ_LT(th->th_seq, tp->rcv_nxt)) {
  723                         /* 
  724                          * The resend was even before 
  725                          * what we have. We need to trim it.
  726                          * Note TSNH (it should be trimmed
  727                          * before the call to tcp_reass()).
  728                          */
  729 #ifdef INVARIANTS
  730                         panic("th->th_seq:%u rcv_nxt:%u tp:%p not pre-trimmed",
  731                               th->th_seq, tp->rcv_nxt, tp);
  732 #else
  733                         i = tp->rcv_nxt - th->th_seq;
  734 #ifdef TCP_REASS_LOGGING
  735                         tcp_log_reassm(tp, first, NULL, 0, i, TCP_R_LOG_TRIM, 4);
  736 #endif
  737                         m_adj(m, i);
  738                         th->th_seq += i;
  739                         *tlenp -= i;
  740 #endif
  741                 }
  742 #ifdef INVARIANTS
  743                 firstmbuf = first->tqe_m;
  744 #endif
  745                 tcp_reass_prepend(tp, first, m, th, *tlenp, mlast, lenofoh);
  746 #ifdef INVARIANTS
  747                 if (firstmbuf == first->tqe_m) {
  748                         panic("First stayed same m:%p foobar:%p first->tqe_m:%p tp:%p first:%p",
  749                               m, firstmbuf, first->tqe_m, tp, first);
  750                 } else if (first->tqe_m != m) {
  751                         panic("First did not change to m:%p foobar:%p first->tqe_m:%p tp:%p first:%p",
  752                               m, firstmbuf, first->tqe_m, tp, first);
  753                 }
  754 #endif
  755                 tp->t_segqmbuflen += lenofoh;
  756                 *seq_start = first->tqe_start;
  757                 *tlenp = first->tqe_len;
  758                 goto present;
  759         } else if (SEQ_LT((th->th_seq + *tlenp), first->tqe_start)) {
  760                 /* New segment is before our earliest segment. */
  761                 /**
  762                  *           first---->+
  763                  *                      v
  764                  *  rea=                |---| ....
  765                  *  new"         |---|
  766                  *
  767                  */
  768                 goto new_entry;
  769         }
  770         /*
  771          * Find a segment which begins after this one does.
  772          */
  773 #ifdef TCP_REASS_COUNTERS
  774         counter_u64_add(reass_fullwalk, 1);
  775 #endif
  776         TAILQ_FOREACH(q, &tp->t_segq, tqe_q) {
  777                 if (SEQ_GT(q->tqe_start, th->th_seq))
  778                         break;
  779         }
  780         p = TAILQ_PREV(q, tsegqe_head, tqe_q);
  781         /**
  782          * Now is this fit just in-between only? 
  783          * i.e.:
  784          *      p---+        +----q
  785          *          v        v
  786          *     res= |--|     |--|    |--|
  787          *     nee       |-|
  788          */
  789         if (SEQ_LT((th->th_seq + *tlenp), q->tqe_start) &&
  790             ((p == NULL) || (SEQ_GT(th->th_seq, (p->tqe_start + p->tqe_len))))) {
  791                 /* Yep no overlap */
  792                 goto new_entry;
  793         }
  794         /**
  795          * If we reach here we have some (possibly all) overlap
  796          * such as:
  797          *     res=     |--|     |--|    |--|
  798          *     new=  |----|
  799          * or  new=  |-----------------|
  800          * or  new=      |--------|
  801          * or  new=            |---|
  802          * or  new=            |-----------|
  803          */
  804         if ((p != NULL) &&
  805             (SEQ_LEQ(th->th_seq, (p->tqe_start + p->tqe_len)))) {
  806                 /* conversion to int (in i) handles seq wraparound */
  807 
  808 #ifdef TCP_REASS_COUNTERS
  809                 counter_u64_add(reass_path4, 1);
  810 #endif
  811                 i = p->tqe_start + p->tqe_len - th->th_seq;
  812                 if (i >= 0) {
  813                         if (i >= *tlenp) {
  814                                 /**
  815                                  *       prev seg---->+
  816                                  *                    v
  817                                  *  reassembly buffer |---|
  818                                  *  new segment        |-|
  819                                  */
  820                                 TCPSTAT_INC(tcps_rcvduppack);
  821                                 TCPSTAT_ADD(tcps_rcvdupbyte, *tlenp);
  822                                 *tlenp = p->tqe_len;
  823                                 *seq_start = p->tqe_start;
  824                                 m_freem(m);
  825                                 /*
  826                                  * Try to present any queued data
  827                                  * at the left window edge to the user.
  828                                  * This is needed after the 3-WHS
  829                                  * completes. Note this probably
  830                                  * will not work and we will return.
  831                                  */
  832                                 return (0);
  833                         }
  834                         if (i > 0) {
  835                                 /**
  836                                  *       prev seg---->+
  837                                  *                    v
  838                                  *  reassembly buffer |---|
  839                                  *  new segment         |-----|
  840                                  */
  841 #ifdef TCP_REASS_COUNTERS
  842                                 counter_u64_add(reass_path5, 1);
  843 #endif
  844 #ifdef TCP_REASS_LOGGING
  845                                 tcp_log_reassm(tp, p, NULL, 0, i, TCP_R_LOG_TRIM, 5);
  846 #endif
  847                                 m_adj(m, i);
  848                                 *tlenp -= i;
  849                                 th->th_seq += i;
  850                         }
  851                 }
  852                 if (th->th_seq == (p->tqe_start + p->tqe_len)) {
  853                         /* 
  854                          * If dovetails in with this one 
  855                          * append it.
  856                          */
  857                         /**
  858                          *       prev seg---->+
  859                          *                    v
  860                          *  reassembly buffer |--|     |---|
  861                          *  new segment          |--|
  862                          * (note: it was trimmed above if it overlapped)
  863                          */
  864                         tcp_reass_append(tp, p, m, th, *tlenp, mlast, lenofoh);
  865                         tp->t_segqmbuflen += lenofoh;
  866                 } else {
  867 #ifdef INVARIANTS
  868                         panic("Impossible cut th_seq:%u p->seq:%u(%d) p:%p tp:%p",
  869                               th->th_seq, p->tqe_start, p->tqe_len,
  870                               p, tp);
  871 #endif
  872                         *tlenp = 0;
  873                         m_freem(m);
  874                         return (0);
  875                 }
  876                 q = p;
  877         } else {
  878                 /*
  879                  * The new data runs over the 
  880                  * top of previously sack'd data (in q).
  881                  * It may be partially overlapping, or
  882                  * it may overlap the entire segment.
  883                  */
  884 #ifdef TCP_REASS_COUNTERS
  885                 counter_u64_add(reass_path6, 1);
  886 #endif
  887                 if (SEQ_GEQ((th->th_seq + *tlenp), (q->tqe_start + q->tqe_len))) {
  888                         /* It consumes it all */
  889                         /**
  890                          *             next seg---->+
  891                          *                          v
  892                          *  reassembly buffer |--|     |---|
  893                          *  new segment              |----------|
  894                          */
  895 #ifdef TCP_REASS_COUNTERS
  896                         counter_u64_add(reass_path7, 1);
  897 #endif
  898                         tcp_reass_replace(tp, q, m, th->th_seq, *tlenp, mlast, lenofoh, th->th_flags);
  899                 } else {
  900                         /* 
  901                          * We just need to prepend the data
  902                          * to this. It does not overrun
  903                          * the end.
  904                          */
  905                         /**
  906                          *                next seg---->+
  907                          *                             v
  908                          *  reassembly buffer |--|     |---|
  909                          *  new segment                   |----------|
  910                          */
  911                         tcp_reass_prepend(tp, q, m, th, *tlenp, mlast, lenofoh);
  912                         tp->t_segqmbuflen += lenofoh;
  913                 }
  914         }
  915         /* Now does it go further than that? */
  916         tcp_reass_merge_forward(tp, q);
  917         *seq_start = q->tqe_start;
  918         *tlenp = q->tqe_len;
  919         goto present;
  920 
  921         /* 
  922          * When we reach here we can't combine it 
  923          * with any existing segment.
  924          *
  925          * Limit the number of segments that can be queued to reduce the
  926          * potential for mbuf exhaustion. For best performance, we want to be
  927          * able to queue a full window's worth of segments. The size of the
  928          * socket receive buffer determines our advertised window and grows
  929          * automatically when socket buffer autotuning is enabled. Use it as the
  930          * basis for our queue limit.
  931          *
  932          * However, allow the user to specify a ceiling for the number of
  933          * segments in each queue.
  934          *
  935          * Always let the missing segment through which caused this queue.
  936          * NB: Access to the socket buffer is left intentionally unlocked as we
  937          * can tolerate stale information here.
  938          *
  939          * XXXLAS: Using sbspace(so->so_rcv) instead of so->so_rcv.sb_hiwat
  940          * should work but causes packets to be dropped when they shouldn't.
  941          * Investigate why and re-evaluate the below limit after the behaviour
  942          * is understood.
  943          */
  944 new_entry:
  945         if (th->th_seq == tp->rcv_nxt && TCPS_HAVEESTABLISHED(tp->t_state)) {
  946                 tp->rcv_nxt += *tlenp;
  947                 flags = th->th_flags & TH_FIN;
  948                 TCPSTAT_INC(tcps_rcvoopack);
  949                 TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
  950                 SOCKBUF_LOCK(&so->so_rcv);
  951                 if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
  952                         m_freem(m);
  953                 } else {
  954                         sbappendstream_locked(&so->so_rcv, m, 0);
  955                 }
  956                 sorwakeup_locked(so);
  957                 return (flags);
  958         }
  959         if (tcp_new_limits) {
  960                 if ((tp->t_segqlen > tcp_reass_queue_guard) &&
  961                     (*tlenp < MSIZE)) {
  962                         /* 
  963                          * This is really a lie, we are not full but
  964                          * are getting a segment that is above 
  965                          * guard threshold. If it is and its below
  966                          * a mbuf size (256) we drop it if it
  967                          * can't fill in some place.
  968                          */
  969                         TCPSTAT_INC(tcps_rcvreassfull);
  970                         *tlenp = 0;
  971                         if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) {
  972                                 log(LOG_DEBUG, "%s; %s: queue limit reached, "
  973                                     "segment dropped\n", s, __func__);
  974                                 free(s, M_TCPLOG);
  975                         }
  976                         m_freem(m);
  977 #ifdef TCP_REASS_LOGGING
  978                         tcp_reass_log_dump(tp);
  979 #endif
  980                         return (0);
  981                 }
  982         } else {
  983                 if (tp->t_segqlen >= min((so->so_rcv.sb_hiwat / tp->t_maxseg) + 1,
  984                                          tcp_reass_maxqueuelen)) {
  985                         TCPSTAT_INC(tcps_rcvreassfull);
  986                         *tlenp = 0;
  987                         if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) {
  988                                 log(LOG_DEBUG, "%s; %s: queue limit reached, "
  989                                     "segment dropped\n", s, __func__);
  990                                 free(s, M_TCPLOG);
  991                         }
  992                         m_freem(m);
  993 #ifdef TCP_REASS_LOGGING
  994                         tcp_reass_log_dump(tp);
  995 #endif
  996                         return (0);
  997                 }
  998         }
  999         /*
 1000          * Allocate a new queue entry. If we can't, or hit the zone limit
 1001          * just drop the pkt.
 1002          */
 1003         te = uma_zalloc(tcp_reass_zone, M_NOWAIT);
 1004         if (te == NULL) {
 1005                 TCPSTAT_INC(tcps_rcvmemdrop);
 1006                 m_freem(m);
 1007                 *tlenp = 0;
 1008                 if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL,
 1009                                        NULL))) {
 1010                         log(LOG_DEBUG, "%s; %s: global zone limit "
 1011                             "reached, segment dropped\n", s, __func__);
 1012                         free(s, M_TCPLOG);
 1013                 }
 1014                 return (0);
 1015         }
 1016         tp->t_segqlen++;
 1017         tp->t_rcvoopack++;
 1018         TCPSTAT_INC(tcps_rcvoopack);
 1019         TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
 1020         /* Insert the new segment queue entry into place. */
 1021         te->tqe_m = m;
 1022         te->tqe_flags = th->th_flags;
 1023         te->tqe_len = *tlenp;
 1024         te->tqe_start = th->th_seq;
 1025         te->tqe_last = mlast;
 1026         te->tqe_mbuf_cnt = lenofoh;
 1027         tp->t_segqmbuflen += te->tqe_mbuf_cnt;
 1028         if (p == NULL) {
 1029                 TAILQ_INSERT_HEAD(&tp->t_segq, te, tqe_q);
 1030         } else {
 1031                 TAILQ_INSERT_AFTER(&tp->t_segq, p, te, tqe_q);
 1032         }
 1033 #ifdef TCP_REASS_LOGGING
 1034         tcp_reass_log_new_in(tp, th->th_seq, *tlenp, m, TCP_R_LOG_NEW_ENTRY, te);
 1035 #endif
 1036 present:
 1037         /*
 1038          * Present data to user, advancing rcv_nxt through
 1039          * completed sequence space.
 1040          */
 1041         if (!TCPS_HAVEESTABLISHED(tp->t_state))
 1042                 return (0);
 1043         q = TAILQ_FIRST(&tp->t_segq);
 1044         KASSERT(q == NULL || SEQ_GEQ(q->tqe_start, tp->rcv_nxt),
 1045                 ("Reassembly queue for %p has stale entry at head", tp));
 1046         if (!q || q->tqe_start != tp->rcv_nxt) {
 1047 #ifdef TCP_REASS_LOGGING
 1048                 tcp_reass_log_dump(tp);
 1049 #endif
 1050                 return (0);
 1051         }
 1052         SOCKBUF_LOCK(&so->so_rcv);
 1053         do {
 1054                 tp->rcv_nxt += q->tqe_len;
 1055                 flags = q->tqe_flags & TH_FIN;
 1056                 nq = TAILQ_NEXT(q, tqe_q);
 1057                 TAILQ_REMOVE(&tp->t_segq, q, tqe_q);
 1058                 if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
 1059                         m_freem(q->tqe_m);
 1060                 } else {
 1061 #ifdef TCP_REASS_LOGGING
 1062                         tcp_reass_log_new_in(tp, q->tqe_start, q->tqe_len, q->tqe_m, TCP_R_LOG_READ, q);
 1063                         tcp_log_reassm(tp, q, NULL, th->th_seq, *tlenp, TCP_R_LOG_READ, 1);
 1064 #endif
 1065                         sbappendstream_locked(&so->so_rcv, q->tqe_m, 0);
 1066                 }
 1067 #ifdef TCP_REASS_LOGGING
 1068                 tcp_log_reassm(tp, q, NULL, th->th_seq, *tlenp, TCP_R_LOG_READ, 2);
 1069 #endif
 1070                 KASSERT(tp->t_segqmbuflen >= q->tqe_mbuf_cnt,
 1071                         ("tp:%p seg queue goes negative", tp));
 1072                 tp->t_segqmbuflen -= q->tqe_mbuf_cnt;
 1073                 uma_zfree(tcp_reass_zone, q);
 1074                 tp->t_segqlen--;
 1075                 q = nq;
 1076         } while (q && q->tqe_start == tp->rcv_nxt);
 1077         if (TAILQ_EMPTY(&tp->t_segq) &&
 1078             (tp->t_segqmbuflen != 0)) {
 1079 #ifdef INVARIANTS
 1080                 panic("tp:%p segq:%p len:%d queue empty",
 1081                       tp, &tp->t_segq, tp->t_segqmbuflen);
 1082 #else
 1083 #ifdef TCP_REASS_LOGGING
 1084                 tcp_log_reassm(tp, NULL, NULL, th->th_seq, *tlenp, TCP_R_LOG_ZERO, 0);
 1085 #endif
 1086                 tp->t_segqmbuflen = 0;
 1087 #endif
 1088         }
 1089 #ifdef TCP_REASS_LOGGING
 1090         tcp_reass_log_dump(tp);
 1091 #endif
 1092         sorwakeup_locked(so);
 1093         return (flags);
 1094 }

Cache object: 751671fa85e693939511c63a3bd76b4b


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.