The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/net/slcompress.c

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    1 /*-
    2  * Copyright (c) 1989, 1993, 1994
    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  *      @(#)slcompress.c        8.2 (Berkeley) 4/16/94
   30  * $FreeBSD$
   31  */
   32 
   33 /*
   34  * Routines to compress and uncompess tcp packets (for transmission
   35  * over low speed serial lines.
   36  *
   37  * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
   38  *      - Initial distribution.
   39  *
   40  */
   41 
   42 #include <sys/param.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/systm.h>
   45 
   46 #include <netinet/in.h>
   47 #include <netinet/in_systm.h>
   48 #include <netinet/ip.h>
   49 #include <netinet/tcp.h>
   50 
   51 #include <net/slcompress.h>
   52 
   53 #ifndef SL_NO_STATS
   54 #define INCR(counter) ++comp->counter;
   55 #else
   56 #define INCR(counter)
   57 #endif
   58 
   59 #define BCMP(p1, p2, n) bcmp((void *)(p1), (void *)(p2), (int)(n))
   60 #define BCOPY(p1, p2, n) bcopy((void *)(p1), (void *)(p2), (int)(n))
   61 
   62 void
   63 sl_compress_init(comp, max_state)
   64         struct slcompress *comp;
   65         int max_state;
   66 {
   67         register u_int i;
   68         register struct cstate *tstate = comp->tstate;
   69 
   70         if (max_state == -1) {
   71                 max_state = MAX_STATES - 1;
   72                 bzero((char *)comp, sizeof(*comp));
   73         } else {
   74                 /* Don't reset statistics */
   75                 bzero((char *)comp->tstate, sizeof(comp->tstate));
   76                 bzero((char *)comp->rstate, sizeof(comp->rstate));
   77         }
   78         for (i = max_state; i > 0; --i) {
   79                 tstate[i].cs_id = i;
   80                 tstate[i].cs_next = &tstate[i - 1];
   81         }
   82         tstate[0].cs_next = &tstate[max_state];
   83         tstate[0].cs_id = 0;
   84         comp->last_cs = &tstate[0];
   85         comp->last_recv = 255;
   86         comp->last_xmit = 255;
   87         comp->flags = SLF_TOSS;
   88 }
   89 
   90 
   91 /* ENCODE encodes a number that is known to be non-zero.  ENCODEZ
   92  * checks for zero (since zero has to be encoded in the long, 3 byte
   93  * form).
   94  */
   95 #define ENCODE(n) { \
   96         if ((u_int16_t)(n) >= 256) { \
   97                 *cp++ = 0; \
   98                 cp[1] = (n); \
   99                 cp[0] = (n) >> 8; \
  100                 cp += 2; \
  101         } else { \
  102                 *cp++ = (n); \
  103         } \
  104 }
  105 #define ENCODEZ(n) { \
  106         if ((u_int16_t)(n) >= 256 || (u_int16_t)(n) == 0) { \
  107                 *cp++ = 0; \
  108                 cp[1] = (n); \
  109                 cp[0] = (n) >> 8; \
  110                 cp += 2; \
  111         } else { \
  112                 *cp++ = (n); \
  113         } \
  114 }
  115 
  116 #define DECODEL(f) { \
  117         if (*cp == 0) {\
  118                 (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \
  119                 cp += 3; \
  120         } else { \
  121                 (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \
  122         } \
  123 }
  124 
  125 #define DECODES(f) { \
  126         if (*cp == 0) {\
  127                 (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \
  128                 cp += 3; \
  129         } else { \
  130                 (f) = htons(ntohs(f) + (u_int32_t)*cp++); \
  131         } \
  132 }
  133 
  134 #define DECODEU(f) { \
  135         if (*cp == 0) {\
  136                 (f) = htons((cp[1] << 8) | cp[2]); \
  137                 cp += 3; \
  138         } else { \
  139                 (f) = htons((u_int32_t)*cp++); \
  140         } \
  141 }
  142 
  143 /*
  144  * Attempt to compress an outgoing TCP packet and return the type of
  145  * the result.  The caller must have already verified that the protocol
  146  * is TCP.  The first mbuf must contain the complete IP and TCP headers,
  147  * and "ip" must be == mtod(m, struct ip *).  "comp" supplies the
  148  * compression state, and "compress_cid" tells us whether it is OK
  149  * to leave out the CID field when feasible.
  150  *
  151  * The caller is responsible for adjusting m->m_pkthdr.len upon return,
  152  * if m is an M_PKTHDR mbuf.
  153  */
  154 u_int
  155 sl_compress_tcp(m, ip, comp, compress_cid)
  156         struct mbuf *m;
  157         register struct ip *ip;
  158         struct slcompress *comp;
  159         int compress_cid;
  160 {
  161         register struct cstate *cs = comp->last_cs->cs_next;
  162         register u_int hlen = ip->ip_hl;
  163         register struct tcphdr *oth;
  164         register struct tcphdr *th;
  165         register u_int deltaS, deltaA;
  166         register u_int changes = 0;
  167         u_char new_seq[16];
  168         register u_char *cp = new_seq;
  169 
  170         /*
  171          * Bail if this is an IP fragment or if the TCP packet isn't
  172          * `compressible' (i.e., ACK isn't set or some other control bit is
  173          * set).  (We assume that the caller has already made sure the
  174          * packet is IP proto TCP).
  175          */
  176         if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40)
  177                 return (TYPE_IP);
  178 
  179         th = (struct tcphdr *)&((int32_t *)ip)[hlen];
  180         if ((th->th_flags & (TH_SYN|TH_FIN|TH_RST|TH_ACK)) != TH_ACK)
  181                 return (TYPE_IP);
  182         /*
  183          * Packet is compressible -- we're going to send either a
  184          * COMPRESSED_TCP or UNCOMPRESSED_TCP packet.  Either way we need
  185          * to locate (or create) the connection state.  Special case the
  186          * most recently used connection since it's most likely to be used
  187          * again & we don't have to do any reordering if it's used.
  188          */
  189         INCR(sls_packets)
  190         if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr ||
  191             ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr ||
  192             *(int32_t *)th != ((int32_t *)&cs->cs_ip)[cs->cs_ip.ip_hl]) {
  193                 /*
  194                  * Wasn't the first -- search for it.
  195                  *
  196                  * States are kept in a circularly linked list with
  197                  * last_cs pointing to the end of the list.  The
  198                  * list is kept in lru order by moving a state to the
  199                  * head of the list whenever it is referenced.  Since
  200                  * the list is short and, empirically, the connection
  201                  * we want is almost always near the front, we locate
  202                  * states via linear search.  If we don't find a state
  203                  * for the datagram, the oldest state is (re-)used.
  204                  */
  205                 register struct cstate *lcs;
  206                 register struct cstate *lastcs = comp->last_cs;
  207 
  208                 do {
  209                         lcs = cs; cs = cs->cs_next;
  210                         INCR(sls_searches)
  211                         if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr
  212                             && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr
  213                             && *(int32_t *)th ==
  214                             ((int32_t *)&cs->cs_ip)[cs->cs_ip.ip_hl])
  215                                 goto found;
  216                 } while (cs != lastcs);
  217 
  218                 /*
  219                  * Didn't find it -- re-use oldest cstate.  Send an
  220                  * uncompressed packet that tells the other side what
  221                  * connection number we're using for this conversation.
  222                  * Note that since the state list is circular, the oldest
  223                  * state points to the newest and we only need to set
  224                  * last_cs to update the lru linkage.
  225                  */
  226                 INCR(sls_misses)
  227                 comp->last_cs = lcs;
  228                 hlen += th->th_off;
  229                 hlen <<= 2;
  230                 if (hlen > m->m_len)
  231                     return TYPE_IP;
  232                 goto uncompressed;
  233 
  234         found:
  235                 /*
  236                  * Found it -- move to the front on the connection list.
  237                  */
  238                 if (cs == lastcs)
  239                         comp->last_cs = lcs;
  240                 else {
  241                         lcs->cs_next = cs->cs_next;
  242                         cs->cs_next = lastcs->cs_next;
  243                         lastcs->cs_next = cs;
  244                 }
  245         }
  246 
  247         /*
  248          * Make sure that only what we expect to change changed. The first
  249          * line of the `if' checks the IP protocol version, header length &
  250          * type of service.  The 2nd line checks the "Don't fragment" bit.
  251          * The 3rd line checks the time-to-live and protocol (the protocol
  252          * check is unnecessary but costless).  The 4th line checks the TCP
  253          * header length.  The 5th line checks IP options, if any.  The 6th
  254          * line checks TCP options, if any.  If any of these things are
  255          * different between the previous & current datagram, we send the
  256          * current datagram `uncompressed'.
  257          */
  258         oth = (struct tcphdr *)&((int32_t *)&cs->cs_ip)[hlen];
  259         deltaS = hlen;
  260         hlen += th->th_off;
  261         hlen <<= 2;
  262         if (hlen > m->m_len)
  263             return TYPE_IP;
  264 
  265         if (((u_int16_t *)ip)[0] != ((u_int16_t *)&cs->cs_ip)[0] ||
  266             ((u_int16_t *)ip)[3] != ((u_int16_t *)&cs->cs_ip)[3] ||
  267             ((u_int16_t *)ip)[4] != ((u_int16_t *)&cs->cs_ip)[4] ||
  268             th->th_off != oth->th_off ||
  269             (deltaS > 5 &&
  270              BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) ||
  271             (th->th_off > 5 &&
  272              BCMP(th + 1, oth + 1, (th->th_off - 5) << 2)))
  273                 goto uncompressed;
  274 
  275         /*
  276          * Figure out which of the changing fields changed.  The
  277          * receiver expects changes in the order: urgent, window,
  278          * ack, seq (the order minimizes the number of temporaries
  279          * needed in this section of code).
  280          */
  281         if (th->th_flags & TH_URG) {
  282                 deltaS = ntohs(th->th_urp);
  283                 ENCODEZ(deltaS);
  284                 changes |= NEW_U;
  285         } else if (th->th_urp != oth->th_urp)
  286                 /* argh! URG not set but urp changed -- a sensible
  287                  * implementation should never do this but RFC793
  288                  * doesn't prohibit the change so we have to deal
  289                  * with it. */
  290                  goto uncompressed;
  291 
  292         deltaS = (u_int16_t)(ntohs(th->th_win) - ntohs(oth->th_win));
  293         if (deltaS) {
  294                 ENCODE(deltaS);
  295                 changes |= NEW_W;
  296         }
  297 
  298         deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack);
  299         if (deltaA) {
  300                 if (deltaA > 0xffff)
  301                         goto uncompressed;
  302                 ENCODE(deltaA);
  303                 changes |= NEW_A;
  304         }
  305 
  306         deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq);
  307         if (deltaS) {
  308                 if (deltaS > 0xffff)
  309                         goto uncompressed;
  310                 ENCODE(deltaS);
  311                 changes |= NEW_S;
  312         }
  313 
  314         switch(changes) {
  315 
  316         case 0:
  317                 /*
  318                  * Nothing changed. If this packet contains data and the
  319                  * last one didn't, this is probably a data packet following
  320                  * an ack (normal on an interactive connection) and we send
  321                  * it compressed.  Otherwise it's probably a retransmit,
  322                  * retransmitted ack or window probe.  Send it uncompressed
  323                  * in case the other side missed the compressed version.
  324                  */
  325                 if (ip->ip_len != cs->cs_ip.ip_len &&
  326                     ntohs(cs->cs_ip.ip_len) == hlen)
  327                         break;
  328 
  329                 /* FALLTHROUGH */
  330 
  331         case SPECIAL_I:
  332         case SPECIAL_D:
  333                 /*
  334                  * actual changes match one of our special case encodings --
  335                  * send packet uncompressed.
  336                  */
  337                 goto uncompressed;
  338 
  339         case NEW_S|NEW_A:
  340                 if (deltaS == deltaA &&
  341                     deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
  342                         /* special case for echoed terminal traffic */
  343                         changes = SPECIAL_I;
  344                         cp = new_seq;
  345                 }
  346                 break;
  347 
  348         case NEW_S:
  349                 if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
  350                         /* special case for data xfer */
  351                         changes = SPECIAL_D;
  352                         cp = new_seq;
  353                 }
  354                 break;
  355         }
  356 
  357         deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id);
  358         if (deltaS != 1) {
  359                 ENCODEZ(deltaS);
  360                 changes |= NEW_I;
  361         }
  362         if (th->th_flags & TH_PUSH)
  363                 changes |= TCP_PUSH_BIT;
  364         /*
  365          * Grab the cksum before we overwrite it below.  Then update our
  366          * state with this packet's header.
  367          */
  368         deltaA = ntohs(th->th_sum);
  369         BCOPY(ip, &cs->cs_ip, hlen);
  370 
  371         /*
  372          * We want to use the original packet as our compressed packet.
  373          * (cp - new_seq) is the number of bytes we need for compressed
  374          * sequence numbers.  In addition we need one byte for the change
  375          * mask, one for the connection id and two for the tcp checksum.
  376          * So, (cp - new_seq) + 4 bytes of header are needed.  hlen is how
  377          * many bytes of the original packet to toss so subtract the two to
  378          * get the new packet size.
  379          */
  380         deltaS = cp - new_seq;
  381         cp = (u_char *)ip;
  382         if (compress_cid == 0 || comp->last_xmit != cs->cs_id) {
  383                 comp->last_xmit = cs->cs_id;
  384                 hlen -= deltaS + 4;
  385                 cp += hlen;
  386                 *cp++ = changes | NEW_C;
  387                 *cp++ = cs->cs_id;
  388         } else {
  389                 hlen -= deltaS + 3;
  390                 cp += hlen;
  391                 *cp++ = changes;
  392         }
  393         m->m_len -= hlen;
  394         m->m_data += hlen;
  395         *cp++ = deltaA >> 8;
  396         *cp++ = deltaA;
  397         BCOPY(new_seq, cp, deltaS);
  398         INCR(sls_compressed)
  399         return (TYPE_COMPRESSED_TCP);
  400 
  401         /*
  402          * Update connection state cs & send uncompressed packet ('uncompressed'
  403          * means a regular ip/tcp packet but with the 'conversation id' we hope
  404          * to use on future compressed packets in the protocol field).
  405          */
  406 uncompressed:
  407         BCOPY(ip, &cs->cs_ip, hlen);
  408         ip->ip_p = cs->cs_id;
  409         comp->last_xmit = cs->cs_id;
  410         return (TYPE_UNCOMPRESSED_TCP);
  411 }
  412 
  413 
  414 int
  415 sl_uncompress_tcp(bufp, len, type, comp)
  416         u_char **bufp;
  417         int len;
  418         u_int type;
  419         struct slcompress *comp;
  420 {
  421         u_char *hdr, *cp;
  422         int hlen, vjlen;
  423 
  424         cp = bufp? *bufp: NULL;
  425         vjlen = sl_uncompress_tcp_core(cp, len, len, type, comp, &hdr, &hlen);
  426         if (vjlen < 0)
  427                 return (0);     /* error */
  428         if (vjlen == 0)
  429                 return (len);   /* was uncompressed already */
  430 
  431         cp += vjlen;
  432         len -= vjlen;
  433 
  434         /*
  435          * At this point, cp points to the first byte of data in the
  436          * packet.  If we're not aligned on a 4-byte boundary, copy the
  437          * data down so the ip & tcp headers will be aligned.  Then back up
  438          * cp by the tcp/ip header length to make room for the reconstructed
  439          * header (we assume the packet we were handed has enough space to
  440          * prepend 128 bytes of header).
  441          */
  442         if ((intptr_t)cp & 3) {
  443                 if (len > 0)
  444                         BCOPY(cp, ((intptr_t)cp &~ 3), len);
  445                 cp = (u_char *)((intptr_t)cp &~ 3);
  446         }
  447         cp -= hlen;
  448         len += hlen;
  449         BCOPY(hdr, cp, hlen);
  450 
  451         *bufp = cp;
  452         return (len);
  453 }
  454 
  455 /*
  456  * Uncompress a packet of total length total_len.  The first buflen
  457  * bytes are at buf; this must include the entire (compressed or
  458  * uncompressed) TCP/IP header.  This procedure returns the length
  459  * of the VJ header, with a pointer to the uncompressed IP header
  460  * in *hdrp and its length in *hlenp.
  461  */
  462 int
  463 sl_uncompress_tcp_core(buf, buflen, total_len, type, comp, hdrp, hlenp)
  464         u_char *buf;
  465         int buflen, total_len;
  466         u_int type;
  467         struct slcompress *comp;
  468         u_char **hdrp;
  469         u_int *hlenp;
  470 {
  471         register u_char *cp;
  472         register u_int hlen, changes;
  473         register struct tcphdr *th;
  474         register struct cstate *cs;
  475         register struct ip *ip;
  476         register u_int16_t *bp;
  477         register u_int vjlen;
  478 
  479         switch (type) {
  480 
  481         case TYPE_UNCOMPRESSED_TCP:
  482                 ip = (struct ip *) buf;
  483                 if (ip->ip_p >= MAX_STATES)
  484                         goto bad;
  485                 cs = &comp->rstate[comp->last_recv = ip->ip_p];
  486                 comp->flags &=~ SLF_TOSS;
  487                 ip->ip_p = IPPROTO_TCP;
  488                 /*
  489                  * Calculate the size of the TCP/IP header and make sure that
  490                  * we don't overflow the space we have available for it.
  491                  */
  492                 hlen = ip->ip_hl << 2;
  493                 if (hlen + sizeof(struct tcphdr) > buflen)
  494                         goto bad;
  495                 hlen += ((struct tcphdr *)&((char *)ip)[hlen])->th_off << 2;
  496                 if (hlen > MAX_HDR || hlen > buflen)
  497                         goto bad;
  498                 BCOPY(ip, &cs->cs_ip, hlen);
  499                 cs->cs_hlen = hlen;
  500                 INCR(sls_uncompressedin)
  501                 *hdrp = (u_char *) &cs->cs_ip;
  502                 *hlenp = hlen;
  503                 return (0);
  504 
  505         default:
  506                 goto bad;
  507 
  508         case TYPE_COMPRESSED_TCP:
  509                 break;
  510         }
  511         /* We've got a compressed packet. */
  512         INCR(sls_compressedin)
  513         cp = buf;
  514         changes = *cp++;
  515         if (changes & NEW_C) {
  516                 /* Make sure the state index is in range, then grab the state.
  517                  * If we have a good state index, clear the 'discard' flag. */
  518                 if (*cp >= MAX_STATES)
  519                         goto bad;
  520 
  521                 comp->flags &=~ SLF_TOSS;
  522                 comp->last_recv = *cp++;
  523         } else {
  524                 /* this packet has an implicit state index.  If we've
  525                  * had a line error since the last time we got an
  526                  * explicit state index, we have to toss the packet. */
  527                 if (comp->flags & SLF_TOSS) {
  528                         INCR(sls_tossed)
  529                         return (-1);
  530                 }
  531         }
  532         cs = &comp->rstate[comp->last_recv];
  533         hlen = cs->cs_ip.ip_hl << 2;
  534         th = (struct tcphdr *)&((u_char *)&cs->cs_ip)[hlen];
  535         th->th_sum = htons((*cp << 8) | cp[1]);
  536         cp += 2;
  537         if (changes & TCP_PUSH_BIT)
  538                 th->th_flags |= TH_PUSH;
  539         else
  540                 th->th_flags &=~ TH_PUSH;
  541 
  542         switch (changes & SPECIALS_MASK) {
  543         case SPECIAL_I:
  544                 {
  545                 register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen;
  546                 th->th_ack = htonl(ntohl(th->th_ack) + i);
  547                 th->th_seq = htonl(ntohl(th->th_seq) + i);
  548                 }
  549                 break;
  550 
  551         case SPECIAL_D:
  552                 th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len)
  553                                    - cs->cs_hlen);
  554                 break;
  555 
  556         default:
  557                 if (changes & NEW_U) {
  558                         th->th_flags |= TH_URG;
  559                         DECODEU(th->th_urp)
  560                 } else
  561                         th->th_flags &=~ TH_URG;
  562                 if (changes & NEW_W)
  563                         DECODES(th->th_win)
  564                 if (changes & NEW_A)
  565                         DECODEL(th->th_ack)
  566                 if (changes & NEW_S)
  567                         DECODEL(th->th_seq)
  568                 break;
  569         }
  570         if (changes & NEW_I) {
  571                 DECODES(cs->cs_ip.ip_id)
  572         } else
  573                 cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1);
  574 
  575         /*
  576          * At this point, cp points to the first byte of data in the
  577          * packet.  Fill in the IP total length and update the IP
  578          * header checksum.
  579          */
  580         vjlen = cp - buf;
  581         buflen -= vjlen;
  582         if (buflen < 0)
  583                 /* we must have dropped some characters (crc should detect
  584                  * this but the old slip framing won't) */
  585                 goto bad;
  586 
  587         total_len += cs->cs_hlen - vjlen;
  588         cs->cs_ip.ip_len = htons(total_len);
  589 
  590         /* recompute the ip header checksum */
  591         bp = (u_int16_t *) &cs->cs_ip;
  592         cs->cs_ip.ip_sum = 0;
  593                 for (changes = 0; hlen > 0; hlen -= 2)
  594                         changes += *bp++;
  595                 changes = (changes & 0xffff) + (changes >> 16);
  596                 changes = (changes & 0xffff) + (changes >> 16);
  597         cs->cs_ip.ip_sum = ~ changes;
  598 
  599         *hdrp = (u_char *) &cs->cs_ip;
  600         *hlenp = cs->cs_hlen;
  601         return vjlen;
  602 
  603 bad:
  604         comp->flags |= SLF_TOSS;
  605         INCR(sls_errorin)
  606         return (-1);
  607 }

Cache object: 970c45f75c8c553d18ee7da88dad6b8c


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