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/netinet6/frag6.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 /*      $NetBSD: frag6.c,v 1.31 2006/11/16 01:33:45 christos Exp $      */
    2 /*      $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun Exp $  */
    3 
    4 /*
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.31 2006/11/16 01:33:45 christos Exp $");
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/malloc.h>
   39 #include <sys/mbuf.h>
   40 #include <sys/domain.h>
   41 #include <sys/protosw.h>
   42 #include <sys/socket.h>
   43 #include <sys/errno.h>
   44 #include <sys/time.h>
   45 #include <sys/kernel.h>
   46 #include <sys/syslog.h>
   47 
   48 #include <net/if.h>
   49 #include <net/route.h>
   50 
   51 #include <netinet/in.h>
   52 #include <netinet/in_var.h>
   53 #include <netinet/ip6.h>
   54 #include <netinet6/ip6_var.h>
   55 #include <netinet/icmp6.h>
   56 
   57 #include <net/net_osdep.h>
   58 
   59 /*
   60  * Define it to get a correct behavior on per-interface statistics.
   61  * You will need to perform an extra routing table lookup, per fragment,
   62  * to do it.  This may, or may not be, a performance hit.
   63  */
   64 #define IN6_IFSTAT_STRICT
   65 
   66 static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
   67 static void frag6_deq __P((struct ip6asfrag *));
   68 static void frag6_insque __P((struct ip6q *, struct ip6q *));
   69 static void frag6_remque __P((struct ip6q *));
   70 static void frag6_freef __P((struct ip6q *));
   71 
   72 static int ip6q_locked;
   73 u_int frag6_nfragpackets;
   74 u_int frag6_nfrags;
   75 struct  ip6q ip6q;      /* ip6 reassemble queue */
   76 
   77 static inline int ip6q_lock_try __P((void));
   78 static inline void ip6q_unlock __P((void));
   79 
   80 static inline int
   81 ip6q_lock_try()
   82 {
   83         int s;
   84 
   85         /*
   86          * Use splvm() -- we're bloking things that would cause
   87          * mbuf allocation.
   88          */
   89         s = splvm();
   90         if (ip6q_locked) {
   91                 splx(s);
   92                 return (0);
   93         }
   94         ip6q_locked = 1;
   95         splx(s);
   96         return (1);
   97 }
   98 
   99 static inline void
  100 ip6q_unlock()
  101 {
  102         int s;
  103 
  104         s = splvm();
  105         ip6q_locked = 0;
  106         splx(s);
  107 }
  108 
  109 #ifdef DIAGNOSTIC
  110 #define IP6Q_LOCK()                                                     \
  111 do {                                                                    \
  112         if (ip6q_lock_try() == 0) {                                     \
  113                 printf("%s:%d: ip6q already locked\n", __FILE__, __LINE__); \
  114                 panic("ip6q_lock");                                     \
  115         }                                                               \
  116 } while (/*CONSTCOND*/ 0)
  117 #define IP6Q_LOCK_CHECK()                                               \
  118 do {                                                                    \
  119         if (ip6q_locked == 0) {                                         \
  120                 printf("%s:%d: ip6q lock not held\n", __FILE__, __LINE__); \
  121                 panic("ip6q lock check");                               \
  122         }                                                               \
  123 } while (/*CONSTCOND*/ 0)
  124 #else
  125 #define IP6Q_LOCK()             (void) ip6q_lock_try()
  126 #define IP6Q_LOCK_CHECK()       /* nothing */
  127 #endif
  128 
  129 #define IP6Q_UNLOCK()           ip6q_unlock()
  130 
  131 #ifndef offsetof                /* XXX */
  132 #define offsetof(type, member)  ((size_t)(&((type *)0)->member))
  133 #endif
  134 
  135 /*
  136  * Initialise reassembly queue and fragment identifier.
  137  */
  138 void
  139 frag6_init()
  140 {
  141 
  142         ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
  143 }
  144 
  145 /*
  146  * In RFC2460, fragment and reassembly rule do not agree with each other,
  147  * in terms of next header field handling in fragment header.
  148  * While the sender will use the same value for all of the fragmented packets,
  149  * receiver is suggested not to check the consistency.
  150  *
  151  * fragment rule (p20):
  152  *      (2) A Fragment header containing:
  153  *      The Next Header value that identifies the first header of
  154  *      the Fragmentable Part of the original packet.
  155  *              -> next header field is same for all fragments
  156  *
  157  * reassembly rule (p21):
  158  *      The Next Header field of the last header of the Unfragmentable
  159  *      Part is obtained from the Next Header field of the first
  160  *      fragment's Fragment header.
  161  *              -> should grab it from the first fragment only
  162  *
  163  * The following note also contradicts with fragment rule - noone is going to
  164  * send different fragment with different next header field.
  165  *
  166  * additional note (p22):
  167  *      The Next Header values in the Fragment headers of different
  168  *      fragments of the same original packet may differ.  Only the value
  169  *      from the Offset zero fragment packet is used for reassembly.
  170  *              -> should grab it from the first fragment only
  171  *
  172  * There is no explicit reason given in the RFC.  Historical reason maybe?
  173  */
  174 /*
  175  * Fragment input
  176  */
  177 int
  178 frag6_input(struct mbuf **mp, int *offp, int proto)
  179 {
  180         struct mbuf *m = *mp, *t;
  181         struct ip6_hdr *ip6;
  182         struct ip6_frag *ip6f;
  183         struct ip6q *q6;
  184         struct ip6asfrag *af6, *ip6af, *af6dwn;
  185         int offset = *offp, nxt, i, next;
  186         int first_frag = 0;
  187         int fragoff, frgpartlen;        /* must be larger than u_int16_t */
  188         struct ifnet *dstifp;
  189 #ifdef IN6_IFSTAT_STRICT
  190         static struct route_in6 ro;
  191         struct sockaddr_in6 *dst;
  192 #endif
  193 
  194         ip6 = mtod(m, struct ip6_hdr *);
  195         IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
  196         if (ip6f == NULL)
  197                 return IPPROTO_DONE;
  198 
  199         dstifp = NULL;
  200 #ifdef IN6_IFSTAT_STRICT
  201         /* find the destination interface of the packet. */
  202         dst = (struct sockaddr_in6 *)&ro.ro_dst;
  203         if (ro.ro_rt
  204          && ((ro.ro_rt->rt_flags & RTF_UP) == 0
  205           || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
  206                 RTFREE(ro.ro_rt);
  207                 ro.ro_rt = (struct rtentry *)0;
  208         }
  209         if (ro.ro_rt == NULL) {
  210                 bzero(dst, sizeof(*dst));
  211                 dst->sin6_family = AF_INET6;
  212                 dst->sin6_len = sizeof(struct sockaddr_in6);
  213                 dst->sin6_addr = ip6->ip6_dst;
  214         }
  215         rtalloc((struct route *)&ro);
  216         if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
  217                 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
  218 #else
  219         /* we are violating the spec, this is not the destination interface */
  220         if ((m->m_flags & M_PKTHDR) != 0)
  221                 dstifp = m->m_pkthdr.rcvif;
  222 #endif
  223 
  224         /* jumbo payload can't contain a fragment header */
  225         if (ip6->ip6_plen == 0) {
  226                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
  227                 in6_ifstat_inc(dstifp, ifs6_reass_fail);
  228                 return IPPROTO_DONE;
  229         }
  230 
  231         /*
  232          * check whether fragment packet's fragment length is
  233          * multiple of 8 octets.
  234          * sizeof(struct ip6_frag) == 8
  235          * sizeof(struct ip6_hdr) = 40
  236          */
  237         if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
  238             (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
  239                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
  240                     offsetof(struct ip6_hdr, ip6_plen));
  241                 in6_ifstat_inc(dstifp, ifs6_reass_fail);
  242                 return IPPROTO_DONE;
  243         }
  244 
  245         ip6stat.ip6s_fragments++;
  246         in6_ifstat_inc(dstifp, ifs6_reass_reqd);
  247 
  248         /* offset now points to data portion */
  249         offset += sizeof(struct ip6_frag);
  250 
  251         IP6Q_LOCK();
  252 
  253         /*
  254          * Enforce upper bound on number of fragments.
  255          * If maxfrag is 0, never accept fragments.
  256          * If maxfrag is -1, accept all fragments without limitation.
  257          */
  258         if (ip6_maxfrags < 0)
  259                 ;
  260         else if (frag6_nfrags >= (u_int)ip6_maxfrags)
  261                 goto dropfrag;
  262 
  263         for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
  264                 if (ip6f->ip6f_ident == q6->ip6q_ident &&
  265                     IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
  266                     IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
  267                         break;
  268 
  269         if (q6 == &ip6q) {
  270                 /*
  271                  * the first fragment to arrive, create a reassembly queue.
  272                  */
  273                 first_frag = 1;
  274 
  275                 /*
  276                  * Enforce upper bound on number of fragmented packets
  277                  * for which we attempt reassembly;
  278                  * If maxfragpackets is 0, never accept fragments.
  279                  * If maxfragpackets is -1, accept all fragments without
  280                  * limitation.
  281                  */
  282                 if (ip6_maxfragpackets < 0)
  283                         ;
  284                 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
  285                         goto dropfrag;
  286                 frag6_nfragpackets++;
  287                 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
  288                     M_DONTWAIT);
  289                 if (q6 == NULL)
  290                         goto dropfrag;
  291                 bzero(q6, sizeof(*q6));
  292 
  293                 frag6_insque(q6, &ip6q);
  294 
  295                 /* ip6q_nxt will be filled afterwards, from 1st fragment */
  296                 q6->ip6q_down   = q6->ip6q_up = (struct ip6asfrag *)q6;
  297 #ifdef notyet
  298                 q6->ip6q_nxtp   = (u_char *)nxtp;
  299 #endif
  300                 q6->ip6q_ident  = ip6f->ip6f_ident;
  301                 q6->ip6q_arrive = 0; /* Is it used anywhere? */
  302                 q6->ip6q_ttl    = IPV6_FRAGTTL;
  303                 q6->ip6q_src    = ip6->ip6_src;
  304                 q6->ip6q_dst    = ip6->ip6_dst;
  305                 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
  306 
  307                 q6->ip6q_nfrag = 0;
  308         }
  309 
  310         /*
  311          * If it's the 1st fragment, record the length of the
  312          * unfragmentable part and the next header of the fragment header.
  313          */
  314         fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
  315         if (fragoff == 0) {
  316                 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
  317                     sizeof(struct ip6_frag);
  318                 q6->ip6q_nxt = ip6f->ip6f_nxt;
  319         }
  320 
  321         /*
  322          * Check that the reassembled packet would not exceed 65535 bytes
  323          * in size.
  324          * If it would exceed, discard the fragment and return an ICMP error.
  325          */
  326         frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
  327         if (q6->ip6q_unfrglen >= 0) {
  328                 /* The 1st fragment has already arrived. */
  329                 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
  330                         icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
  331                             offset - sizeof(struct ip6_frag) +
  332                             offsetof(struct ip6_frag, ip6f_offlg));
  333                         IP6Q_UNLOCK();
  334                         return (IPPROTO_DONE);
  335                 }
  336         } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
  337                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
  338                             offset - sizeof(struct ip6_frag) +
  339                                 offsetof(struct ip6_frag, ip6f_offlg));
  340                 IP6Q_UNLOCK();
  341                 return (IPPROTO_DONE);
  342         }
  343         /*
  344          * If it's the first fragment, do the above check for each
  345          * fragment already stored in the reassembly queue.
  346          */
  347         if (fragoff == 0) {
  348                 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
  349                      af6 = af6dwn) {
  350                         af6dwn = af6->ip6af_down;
  351 
  352                         if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
  353                             IPV6_MAXPACKET) {
  354                                 struct mbuf *merr = IP6_REASS_MBUF(af6);
  355                                 struct ip6_hdr *ip6err;
  356                                 int erroff = af6->ip6af_offset;
  357 
  358                                 /* dequeue the fragment. */
  359                                 frag6_deq(af6);
  360                                 free(af6, M_FTABLE);
  361 
  362                                 /* adjust pointer. */
  363                                 ip6err = mtod(merr, struct ip6_hdr *);
  364 
  365                                 /*
  366                                  * Restore source and destination addresses
  367                                  * in the erroneous IPv6 header.
  368                                  */
  369                                 ip6err->ip6_src = q6->ip6q_src;
  370                                 ip6err->ip6_dst = q6->ip6q_dst;
  371 
  372                                 icmp6_error(merr, ICMP6_PARAM_PROB,
  373                                     ICMP6_PARAMPROB_HEADER,
  374                                     erroff - sizeof(struct ip6_frag) +
  375                                     offsetof(struct ip6_frag, ip6f_offlg));
  376                         }
  377                 }
  378         }
  379 
  380         ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
  381             M_DONTWAIT);
  382         if (ip6af == NULL)
  383                 goto dropfrag;
  384         bzero(ip6af, sizeof(*ip6af));
  385         ip6af->ip6af_head = ip6->ip6_flow;
  386         ip6af->ip6af_len = ip6->ip6_plen;
  387         ip6af->ip6af_nxt = ip6->ip6_nxt;
  388         ip6af->ip6af_hlim = ip6->ip6_hlim;
  389         ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
  390         ip6af->ip6af_off = fragoff;
  391         ip6af->ip6af_frglen = frgpartlen;
  392         ip6af->ip6af_offset = offset;
  393         IP6_REASS_MBUF(ip6af) = m;
  394 
  395         if (first_frag) {
  396                 af6 = (struct ip6asfrag *)q6;
  397                 goto insert;
  398         }
  399 
  400         /*
  401          * Find a segment which begins after this one does.
  402          */
  403         for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
  404              af6 = af6->ip6af_down)
  405                 if (af6->ip6af_off > ip6af->ip6af_off)
  406                         break;
  407 
  408 #if 0
  409         /*
  410          * If there is a preceding segment, it may provide some of
  411          * our data already.  If so, drop the data from the incoming
  412          * segment.  If it provides all of our data, drop us.
  413          */
  414         if (af6->ip6af_up != (struct ip6asfrag *)q6) {
  415                 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
  416                         - ip6af->ip6af_off;
  417                 if (i > 0) {
  418                         if (i >= ip6af->ip6af_frglen)
  419                                 goto dropfrag;
  420                         m_adj(IP6_REASS_MBUF(ip6af), i);
  421                         ip6af->ip6af_off += i;
  422                         ip6af->ip6af_frglen -= i;
  423                 }
  424         }
  425 
  426         /*
  427          * While we overlap succeeding segments trim them or,
  428          * if they are completely covered, dequeue them.
  429          */
  430         while (af6 != (struct ip6asfrag *)q6 &&
  431                ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
  432                 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
  433                 if (i < af6->ip6af_frglen) {
  434                         af6->ip6af_frglen -= i;
  435                         af6->ip6af_off += i;
  436                         m_adj(IP6_REASS_MBUF(af6), i);
  437                         break;
  438                 }
  439                 af6 = af6->ip6af_down;
  440                 m_freem(IP6_REASS_MBUF(af6->ip6af_up));
  441                 frag6_deq(af6->ip6af_up);
  442         }
  443 #else
  444         /*
  445          * If the incoming framgent overlaps some existing fragments in
  446          * the reassembly queue, drop it, since it is dangerous to override
  447          * existing fragments from a security point of view.
  448          * We don't know which fragment is the bad guy - here we trust
  449          * fragment that came in earlier, with no real reason.
  450          */
  451         if (af6->ip6af_up != (struct ip6asfrag *)q6) {
  452                 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
  453                         - ip6af->ip6af_off;
  454                 if (i > 0) {
  455 #if 0                           /* suppress the noisy log */
  456                         log(LOG_ERR, "%d bytes of a fragment from %s "
  457                             "overlaps the previous fragment\n",
  458                             i, ip6_sprintf(&q6->ip6q_src));
  459 #endif
  460                         free(ip6af, M_FTABLE);
  461                         goto dropfrag;
  462                 }
  463         }
  464         if (af6 != (struct ip6asfrag *)q6) {
  465                 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
  466                 if (i > 0) {
  467 #if 0                           /* suppress the noisy log */
  468                         log(LOG_ERR, "%d bytes of a fragment from %s "
  469                             "overlaps the succeeding fragment",
  470                             i, ip6_sprintf(&q6->ip6q_src));
  471 #endif
  472                         free(ip6af, M_FTABLE);
  473                         goto dropfrag;
  474                 }
  475         }
  476 #endif
  477 
  478 insert:
  479 
  480         /*
  481          * Stick new segment in its place;
  482          * check for complete reassembly.
  483          * Move to front of packet queue, as we are
  484          * the most recently active fragmented packet.
  485          */
  486         frag6_enq(ip6af, af6->ip6af_up);
  487         frag6_nfrags++;
  488         q6->ip6q_nfrag++;
  489 #if 0 /* xxx */
  490         if (q6 != ip6q.ip6q_next) {
  491                 frag6_remque(q6);
  492                 frag6_insque(q6, &ip6q);
  493         }
  494 #endif
  495         next = 0;
  496         for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
  497              af6 = af6->ip6af_down) {
  498                 if (af6->ip6af_off != next) {
  499                         IP6Q_UNLOCK();
  500                         return IPPROTO_DONE;
  501                 }
  502                 next += af6->ip6af_frglen;
  503         }
  504         if (af6->ip6af_up->ip6af_mff) {
  505                 IP6Q_UNLOCK();
  506                 return IPPROTO_DONE;
  507         }
  508 
  509         /*
  510          * Reassembly is complete; concatenate fragments.
  511          */
  512         ip6af = q6->ip6q_down;
  513         t = m = IP6_REASS_MBUF(ip6af);
  514         af6 = ip6af->ip6af_down;
  515         frag6_deq(ip6af);
  516         while (af6 != (struct ip6asfrag *)q6) {
  517                 af6dwn = af6->ip6af_down;
  518                 frag6_deq(af6);
  519                 while (t->m_next)
  520                         t = t->m_next;
  521                 t->m_next = IP6_REASS_MBUF(af6);
  522                 m_adj(t->m_next, af6->ip6af_offset);
  523                 free(af6, M_FTABLE);
  524                 af6 = af6dwn;
  525         }
  526 
  527         /* adjust offset to point where the original next header starts */
  528         offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
  529         free(ip6af, M_FTABLE);
  530         ip6 = mtod(m, struct ip6_hdr *);
  531         ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr));
  532         ip6->ip6_src = q6->ip6q_src;
  533         ip6->ip6_dst = q6->ip6q_dst;
  534         nxt = q6->ip6q_nxt;
  535 #ifdef notyet
  536         *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
  537 #endif
  538 
  539         /*
  540          * Delete frag6 header with as a few cost as possible.
  541          */
  542         if (offset < m->m_len) {
  543                 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
  544                         offset);
  545                 m->m_data += sizeof(struct ip6_frag);
  546                 m->m_len -= sizeof(struct ip6_frag);
  547         } else {
  548                 /* this comes with no copy if the boundary is on cluster */
  549                 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
  550                         frag6_remque(q6);
  551                         frag6_nfrags -= q6->ip6q_nfrag;
  552                         free(q6, M_FTABLE);
  553                         frag6_nfragpackets--;
  554                         goto dropfrag;
  555                 }
  556                 m_adj(t, sizeof(struct ip6_frag));
  557                 m_cat(m, t);
  558         }
  559 
  560         /*
  561          * Store NXT to the original.
  562          */
  563         {
  564                 u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
  565                 *prvnxtp = nxt;
  566         }
  567 
  568         frag6_remque(q6);
  569         frag6_nfrags -= q6->ip6q_nfrag;
  570         free(q6, M_FTABLE);
  571         frag6_nfragpackets--;
  572 
  573         if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
  574                 int plen = 0;
  575                 for (t = m; t; t = t->m_next)
  576                         plen += t->m_len;
  577                 m->m_pkthdr.len = plen;
  578         }
  579 
  580         ip6stat.ip6s_reassembled++;
  581         in6_ifstat_inc(dstifp, ifs6_reass_ok);
  582 
  583         /*
  584          * Tell launch routine the next header
  585          */
  586 
  587         *mp = m;
  588         *offp = offset;
  589 
  590         IP6Q_UNLOCK();
  591         return nxt;
  592 
  593  dropfrag:
  594         in6_ifstat_inc(dstifp, ifs6_reass_fail);
  595         ip6stat.ip6s_fragdropped++;
  596         m_freem(m);
  597         IP6Q_UNLOCK();
  598         return IPPROTO_DONE;
  599 }
  600 
  601 /*
  602  * Free a fragment reassembly header and all
  603  * associated datagrams.
  604  */
  605 void
  606 frag6_freef(q6)
  607         struct ip6q *q6;
  608 {
  609         struct ip6asfrag *af6, *down6;
  610 
  611         IP6Q_LOCK_CHECK();
  612 
  613         for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
  614              af6 = down6) {
  615                 struct mbuf *m = IP6_REASS_MBUF(af6);
  616 
  617                 down6 = af6->ip6af_down;
  618                 frag6_deq(af6);
  619 
  620                 /*
  621                  * Return ICMP time exceeded error for the 1st fragment.
  622                  * Just free other fragments.
  623                  */
  624                 if (af6->ip6af_off == 0) {
  625                         struct ip6_hdr *ip6;
  626 
  627                         /* adjust pointer */
  628                         ip6 = mtod(m, struct ip6_hdr *);
  629 
  630                         /* restoure source and destination addresses */
  631                         ip6->ip6_src = q6->ip6q_src;
  632                         ip6->ip6_dst = q6->ip6q_dst;
  633 
  634                         icmp6_error(m, ICMP6_TIME_EXCEEDED,
  635                                     ICMP6_TIME_EXCEED_REASSEMBLY, 0);
  636                 } else
  637                         m_freem(m);
  638                 free(af6, M_FTABLE);
  639         }
  640         frag6_remque(q6);
  641         frag6_nfrags -= q6->ip6q_nfrag;
  642         free(q6, M_FTABLE);
  643         frag6_nfragpackets--;
  644 }
  645 
  646 /*
  647  * Put an ip fragment on a reassembly chain.
  648  * Like insque, but pointers in middle of structure.
  649  */
  650 void
  651 frag6_enq(af6, up6)
  652         struct ip6asfrag *af6, *up6;
  653 {
  654 
  655         IP6Q_LOCK_CHECK();
  656 
  657         af6->ip6af_up = up6;
  658         af6->ip6af_down = up6->ip6af_down;
  659         up6->ip6af_down->ip6af_up = af6;
  660         up6->ip6af_down = af6;
  661 }
  662 
  663 /*
  664  * To frag6_enq as remque is to insque.
  665  */
  666 void
  667 frag6_deq(af6)
  668         struct ip6asfrag *af6;
  669 {
  670 
  671         IP6Q_LOCK_CHECK();
  672 
  673         af6->ip6af_up->ip6af_down = af6->ip6af_down;
  674         af6->ip6af_down->ip6af_up = af6->ip6af_up;
  675 }
  676 
  677 void
  678 frag6_insque(new, old)
  679         struct ip6q *new, *old;
  680 {
  681 
  682         IP6Q_LOCK_CHECK();
  683 
  684         new->ip6q_prev = old;
  685         new->ip6q_next = old->ip6q_next;
  686         old->ip6q_next->ip6q_prev= new;
  687         old->ip6q_next = new;
  688 }
  689 
  690 void
  691 frag6_remque(p6)
  692         struct ip6q *p6;
  693 {
  694 
  695         IP6Q_LOCK_CHECK();
  696 
  697         p6->ip6q_prev->ip6q_next = p6->ip6q_next;
  698         p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
  699 }
  700 
  701 /*
  702  * IPv6 reassembling timer processing;
  703  * if a timer expires on a reassembly
  704  * queue, discard it.
  705  */
  706 void
  707 frag6_slowtimo()
  708 {
  709         struct ip6q *q6;
  710         int s = splsoftnet();
  711 
  712         IP6Q_LOCK();
  713         q6 = ip6q.ip6q_next;
  714         if (q6)
  715                 while (q6 != &ip6q) {
  716                         --q6->ip6q_ttl;
  717                         q6 = q6->ip6q_next;
  718                         if (q6->ip6q_prev->ip6q_ttl == 0) {
  719                                 ip6stat.ip6s_fragtimeout++;
  720                                 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
  721                                 frag6_freef(q6->ip6q_prev);
  722                         }
  723                 }
  724         /*
  725          * If we are over the maximum number of fragments
  726          * (due to the limit being lowered), drain off
  727          * enough to get down to the new limit.
  728          */
  729         while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
  730             ip6q.ip6q_prev) {
  731                 ip6stat.ip6s_fragoverflow++;
  732                 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
  733                 frag6_freef(ip6q.ip6q_prev);
  734         }
  735         IP6Q_UNLOCK();
  736 
  737 #if 0
  738         /*
  739          * Routing changes might produce a better route than we last used;
  740          * make sure we notice eventually, even if forwarding only for one
  741          * destination and the cache is never replaced.
  742          */
  743         if (ip6_forward_rt.ro_rt) {
  744                 RTFREE(ip6_forward_rt.ro_rt);
  745                 ip6_forward_rt.ro_rt = 0;
  746         }
  747         if (ipsrcchk_rt.ro_rt) {
  748                 RTFREE(ipsrcchk_rt.ro_rt);
  749                 ipsrcchk_rt.ro_rt = 0;
  750         }
  751 #endif
  752 
  753         splx(s);
  754 }
  755 
  756 /*
  757  * Drain off all datagram fragments.
  758  */
  759 void
  760 frag6_drain()
  761 {
  762 
  763         if (ip6q_lock_try() == 0)
  764                 return;
  765         while (ip6q.ip6q_next != &ip6q) {
  766                 ip6stat.ip6s_fragdropped++;
  767                 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
  768                 frag6_freef(ip6q.ip6q_next);
  769         }
  770         IP6Q_UNLOCK();
  771 }

Cache object: 90398e3304df9346fae53c484f5d563c


[ 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.