tcp_reass.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/8.0/sys/netinet/tcp_reass.c 196019 2009-08-01 19:26:27Z rwatson $");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 #include "opt_tcpdebug.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/kernel.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/socket.h>
   44 #include <sys/socketvar.h>
   45 #include <sys/sysctl.h>
   46 #include <sys/syslog.h>
   47 #include <sys/systm.h>
   48 
   49 #include <vm/uma.h>
   50 
   51 #include <net/if.h>
   52 #include <net/route.h>
   53 #include <net/vnet.h>
   54 
   55 #include <netinet/in.h>
   56 #include <netinet/in_pcb.h>
   57 #include <netinet/in_systm.h>
   58 #include <netinet/in_var.h>
   59 #include <netinet/ip.h>
   60 #include <netinet/ip_var.h>
   61 #include <netinet/ip_options.h>
   62 #include <netinet/ip6.h>
   63 #include <netinet6/in6_pcb.h>
   64 #include <netinet6/ip6_var.h>
   65 #include <netinet6/nd6.h>
   66 #include <netinet/tcp.h>
   67 #include <netinet/tcp_fsm.h>
   68 #include <netinet/tcp_seq.h>
   69 #include <netinet/tcp_timer.h>
   70 #include <netinet/tcp_var.h>
   71 #include <netinet6/tcp6_var.h>
   72 #include <netinet/tcpip.h>
   73 #ifdef TCPDEBUG
   74 #include <netinet/tcp_debug.h>
   75 #endif /* TCPDEBUG */
   76 
   77 static VNET_DEFINE(int, tcp_reass_maxseg);
   78 VNET_DEFINE(int, tcp_reass_qsize);
   79 static VNET_DEFINE(int, tcp_reass_maxqlen);
   80 static VNET_DEFINE(int, tcp_reass_overflows);
   81 
   82 #define V_tcp_reass_maxseg              VNET(tcp_reass_maxseg)
   83 #define V_tcp_reass_maxqlen             VNET(tcp_reass_maxqlen)
   84 #define V_tcp_reass_overflows           VNET(tcp_reass_overflows)
   85 
   86 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0,
   87     "TCP Segment Reassembly Queue");
   88 
   89 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RDTUN,
   90     &VNET_NAME(tcp_reass_maxseg), 0,
   91     "Global maximum number of TCP Segments in Reassembly Queue");
   92 
   93 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD,
   94     &VNET_NAME(tcp_reass_qsize), 0,
   95     "Global number of TCP Segments currently in Reassembly Queue");
   96 
   97 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, maxqlen, CTLFLAG_RW,
   98     &VNET_NAME(tcp_reass_maxqlen), 0,
   99     "Maximum number of TCP Segments per individual Reassembly Queue");
  100 
  101 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, overflows, CTLFLAG_RD,
  102     &VNET_NAME(tcp_reass_overflows), 0,
  103     "Global number of TCP Segment Reassembly Queue Overflows");
  104 
  105 /* Initialize TCP reassembly queue */
  106 static void
  107 tcp_reass_zone_change(void *tag)
  108 {
  109 
  110         V_tcp_reass_maxseg = nmbclusters / 16;
  111         uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
  112 }
  113 
  114 VNET_DEFINE(uma_zone_t, tcp_reass_zone);
  115 
  116 void
  117 tcp_reass_init(void)
  118 {
  119 
  120         V_tcp_reass_maxseg = 0;
  121         V_tcp_reass_qsize = 0;
  122         V_tcp_reass_maxqlen = 48;
  123         V_tcp_reass_overflows = 0;
  124 
  125         V_tcp_reass_maxseg = nmbclusters / 16;
  126         TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments",
  127             &V_tcp_reass_maxseg);
  128         V_tcp_reass_zone = uma_zcreate("tcpreass", sizeof (struct tseg_qent),
  129             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  130         uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
  131         EVENTHANDLER_REGISTER(nmbclusters_change,
  132             tcp_reass_zone_change, NULL, EVENTHANDLER_PRI_ANY);
  133 }
  134 
  135 int
  136 tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m)
  137 {
  138         struct tseg_qent *q;
  139         struct tseg_qent *p = NULL;
  140         struct tseg_qent *nq;
  141         struct tseg_qent *te = NULL;
  142         struct socket *so = tp->t_inpcb->inp_socket;
  143         int flags;
  144 
  145         INP_WLOCK_ASSERT(tp->t_inpcb);
  146 
  147         /*
  148          * XXX: tcp_reass() is rather inefficient with its data structures
  149          * and should be rewritten (see NetBSD for optimizations).
  150          */
  151 
  152         /*
  153          * Call with th==NULL after become established to
  154          * force pre-ESTABLISHED data up to user socket.
  155          */
  156         if (th == NULL)
  157                 goto present;
  158 
  159         /*
  160          * Limit the number of segments in the reassembly queue to prevent
  161          * holding on to too many segments (and thus running out of mbufs).
  162          * Make sure to let the missing segment through which caused this
  163          * queue.  Always keep one global queue entry spare to be able to
  164          * process the missing segment.
  165          */
  166         if (th->th_seq != tp->rcv_nxt &&
  167             (V_tcp_reass_qsize + 1 >= V_tcp_reass_maxseg ||
  168              tp->t_segqlen >= V_tcp_reass_maxqlen)) {
  169                 V_tcp_reass_overflows++;
  170                 TCPSTAT_INC(tcps_rcvmemdrop);
  171                 m_freem(m);
  172                 *tlenp = 0;
  173                 return (0);
  174         }
  175 
  176         /*
  177          * Allocate a new queue entry. If we can't, or hit the zone limit
  178          * just drop the pkt.
  179          */
  180         te = uma_zalloc(V_tcp_reass_zone, M_NOWAIT);
  181         if (te == NULL) {
  182                 TCPSTAT_INC(tcps_rcvmemdrop);
  183                 m_freem(m);
  184                 *tlenp = 0;
  185                 return (0);
  186         }
  187         tp->t_segqlen++;
  188         V_tcp_reass_qsize++;
  189 
  190         /*
  191          * Find a segment which begins after this one does.
  192          */
  193         LIST_FOREACH(q, &tp->t_segq, tqe_q) {
  194                 if (SEQ_GT(q->tqe_th->th_seq, th->th_seq))
  195                         break;
  196                 p = q;
  197         }
  198 
  199         /*
  200          * If there is a preceding segment, it may provide some of
  201          * our data already.  If so, drop the data from the incoming
  202          * segment.  If it provides all of our data, drop us.
  203          */
  204         if (p != NULL) {
  205                 int i;
  206                 /* conversion to int (in i) handles seq wraparound */
  207                 i = p->tqe_th->th_seq + p->tqe_len - th->th_seq;
  208                 if (i > 0) {
  209                         if (i >= *tlenp) {
  210                                 TCPSTAT_INC(tcps_rcvduppack);
  211                                 TCPSTAT_ADD(tcps_rcvdupbyte, *tlenp);
  212                                 m_freem(m);
  213                                 uma_zfree(V_tcp_reass_zone, te);
  214                                 tp->t_segqlen--;
  215                                 V_tcp_reass_qsize--;
  216                                 /*
  217                                  * Try to present any queued data
  218                                  * at the left window edge to the user.
  219                                  * This is needed after the 3-WHS
  220                                  * completes.
  221                                  */
  222                                 goto present;   /* ??? */
  223                         }
  224                         m_adj(m, i);
  225                         *tlenp -= i;
  226                         th->th_seq += i;
  227                 }
  228         }
  229         TCPSTAT_INC(tcps_rcvoopack);
  230         TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
  231 
  232         /*
  233          * While we overlap succeeding segments trim them or,
  234          * if they are completely covered, dequeue them.
  235          */
  236         while (q) {
  237                 int i = (th->th_seq + *tlenp) - q->tqe_th->th_seq;
  238                 if (i <= 0)
  239                         break;
  240                 if (i < q->tqe_len) {
  241                         q->tqe_th->th_seq += i;
  242                         q->tqe_len -= i;
  243                         m_adj(q->tqe_m, i);
  244                         break;
  245                 }
  246 
  247                 nq = LIST_NEXT(q, tqe_q);
  248                 LIST_REMOVE(q, tqe_q);
  249                 m_freem(q->tqe_m);
  250                 uma_zfree(V_tcp_reass_zone, q);
  251                 tp->t_segqlen--;
  252                 V_tcp_reass_qsize--;
  253                 q = nq;
  254         }
  255 
  256         /* Insert the new segment queue entry into place. */
  257         te->tqe_m = m;
  258         te->tqe_th = th;
  259         te->tqe_len = *tlenp;
  260 
  261         if (p == NULL) {
  262                 LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q);
  263         } else {
  264                 LIST_INSERT_AFTER(p, te, tqe_q);
  265         }
  266 
  267 present:
  268         /*
  269          * Present data to user, advancing rcv_nxt through
  270          * completed sequence space.
  271          */
  272         if (!TCPS_HAVEESTABLISHED(tp->t_state))
  273                 return (0);
  274         q = LIST_FIRST(&tp->t_segq);
  275         if (!q || q->tqe_th->th_seq != tp->rcv_nxt)
  276                 return (0);
  277         SOCKBUF_LOCK(&so->so_rcv);
  278         do {
  279                 tp->rcv_nxt += q->tqe_len;
  280                 flags = q->tqe_th->th_flags & TH_FIN;
  281                 nq = LIST_NEXT(q, tqe_q);
  282                 LIST_REMOVE(q, tqe_q);
  283                 if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
  284                         m_freem(q->tqe_m);
  285                 else
  286                         sbappendstream_locked(&so->so_rcv, q->tqe_m);
  287                 uma_zfree(V_tcp_reass_zone, q);
  288                 tp->t_segqlen--;
  289                 V_tcp_reass_qsize--;
  290                 q = nq;
  291         } while (q && q->tqe_th->th_seq == tp->rcv_nxt);
  292         ND6_HINT(tp);
  293         sorwakeup_locked(so);
  294         return (flags);
  295 }
Cache object: 0b17006088899eac2611b0695bf1e54f
[ 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.
FreeBSD/Linux Kernel Cross Reference sys/netinet/tcp_reass.c

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