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lwip/netif/ppp/vj.c@0:d7bd7384a37c, 2016-12-07 (annotated)

Committer:
grzemich
Date:
Wed Dec 07 23:47:50 2016 +0000
Revision:
0:d7bd7384a37c
dgd

Who changed what in which revision?

UserRevisionLine numberNew contents of line
grzemich 0:d7bd7384a37c 1 /*
grzemich 0:d7bd7384a37c 2 * Routines to compress and uncompess tcp packets (for transmission
grzemich 0:d7bd7384a37c 3 * over low speed serial lines.
grzemich 0:d7bd7384a37c 4 *
grzemich 0:d7bd7384a37c 5 * Copyright (c) 1989 Regents of the University of California.
grzemich 0:d7bd7384a37c 6 * All rights reserved.
grzemich 0:d7bd7384a37c 7 *
grzemich 0:d7bd7384a37c 8 * Redistribution and use in source and binary forms are permitted
grzemich 0:d7bd7384a37c 9 * provided that the above copyright notice and this paragraph are
grzemich 0:d7bd7384a37c 10 * duplicated in all such forms and that any documentation,
grzemich 0:d7bd7384a37c 11 * advertising materials, and other materials related to such
grzemich 0:d7bd7384a37c 12 * distribution and use acknowledge that the software was developed
grzemich 0:d7bd7384a37c 13 * by the University of California, Berkeley. The name of the
grzemich 0:d7bd7384a37c 14 * University may not be used to endorse or promote products derived
grzemich 0:d7bd7384a37c 15 * from this software without specific prior written permission.
grzemich 0:d7bd7384a37c 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
grzemich 0:d7bd7384a37c 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
grzemich 0:d7bd7384a37c 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
grzemich 0:d7bd7384a37c 19 *
grzemich 0:d7bd7384a37c 20 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
grzemich 0:d7bd7384a37c 21 * Initial distribution.
grzemich 0:d7bd7384a37c 22 *
grzemich 0:d7bd7384a37c 23 * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au,
grzemich 0:d7bd7384a37c 24 * so that the entire packet being decompressed doesn't have
grzemich 0:d7bd7384a37c 25 * to be in contiguous memory (just the compressed header).
grzemich 0:d7bd7384a37c 26 *
grzemich 0:d7bd7384a37c 27 * Modified March 1998 by Guy Lancaster, glanca@gesn.com,
grzemich 0:d7bd7384a37c 28 * for a 16 bit processor.
grzemich 0:d7bd7384a37c 29 */
grzemich 0:d7bd7384a37c 30
grzemich 0:d7bd7384a37c 31 #include "lwip/opt.h"
grzemich 0:d7bd7384a37c 32
grzemich 0:d7bd7384a37c 33 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
grzemich 0:d7bd7384a37c 34
grzemich 0:d7bd7384a37c 35 #include "ppp.h"
grzemich 0:d7bd7384a37c 36 #include "pppdebug.h"
grzemich 0:d7bd7384a37c 37
grzemich 0:d7bd7384a37c 38 #include "vj.h"
grzemich 0:d7bd7384a37c 39
grzemich 0:d7bd7384a37c 40 #include <string.h>
grzemich 0:d7bd7384a37c 41
grzemich 0:d7bd7384a37c 42 #if VJ_SUPPORT
grzemich 0:d7bd7384a37c 43
grzemich 0:d7bd7384a37c 44 #if LINK_STATS
grzemich 0:d7bd7384a37c 45 #define INCR(counter) ++comp->stats.counter
grzemich 0:d7bd7384a37c 46 #else
grzemich 0:d7bd7384a37c 47 #define INCR(counter)
grzemich 0:d7bd7384a37c 48 #endif
grzemich 0:d7bd7384a37c 49
grzemich 0:d7bd7384a37c 50 void
grzemich 0:d7bd7384a37c 51 vj_compress_init(struct vjcompress *comp)
grzemich 0:d7bd7384a37c 52 {
grzemich 0:d7bd7384a37c 53 register u_char i;
grzemich 0:d7bd7384a37c 54 register struct cstate *tstate = comp->tstate;
grzemich 0:d7bd7384a37c 55
grzemich 0:d7bd7384a37c 56 #if MAX_SLOTS == 0
grzemich 0:d7bd7384a37c 57 memset((char *)comp, 0, sizeof(*comp));
grzemich 0:d7bd7384a37c 58 #endif
grzemich 0:d7bd7384a37c 59 comp->maxSlotIndex = MAX_SLOTS - 1;
grzemich 0:d7bd7384a37c 60 comp->compressSlot = 0; /* Disable slot ID compression by default. */
grzemich 0:d7bd7384a37c 61 for (i = MAX_SLOTS - 1; i > 0; --i) {
grzemich 0:d7bd7384a37c 62 tstate[i].cs_id = i;
grzemich 0:d7bd7384a37c 63 tstate[i].cs_next = &tstate[i - 1];
grzemich 0:d7bd7384a37c 64 }
grzemich 0:d7bd7384a37c 65 tstate[0].cs_next = &tstate[MAX_SLOTS - 1];
grzemich 0:d7bd7384a37c 66 tstate[0].cs_id = 0;
grzemich 0:d7bd7384a37c 67 comp->last_cs = &tstate[0];
grzemich 0:d7bd7384a37c 68 comp->last_recv = 255;
grzemich 0:d7bd7384a37c 69 comp->last_xmit = 255;
grzemich 0:d7bd7384a37c 70 comp->flags = VJF_TOSS;
grzemich 0:d7bd7384a37c 71 }
grzemich 0:d7bd7384a37c 72
grzemich 0:d7bd7384a37c 73
grzemich 0:d7bd7384a37c 74 /* ENCODE encodes a number that is known to be non-zero. ENCODEZ
grzemich 0:d7bd7384a37c 75 * checks for zero (since zero has to be encoded in the long, 3 byte
grzemich 0:d7bd7384a37c 76 * form).
grzemich 0:d7bd7384a37c 77 */
grzemich 0:d7bd7384a37c 78 #define ENCODE(n) { \
grzemich 0:d7bd7384a37c 79 if ((u_short)(n) >= 256) { \
grzemich 0:d7bd7384a37c 80 *cp++ = 0; \
grzemich 0:d7bd7384a37c 81 cp[1] = (u_char)(n); \
grzemich 0:d7bd7384a37c 82 cp[0] = (u_char)((n) >> 8); \
grzemich 0:d7bd7384a37c 83 cp += 2; \
grzemich 0:d7bd7384a37c 84 } else { \
grzemich 0:d7bd7384a37c 85 *cp++ = (u_char)(n); \
grzemich 0:d7bd7384a37c 86 } \
grzemich 0:d7bd7384a37c 87 }
grzemich 0:d7bd7384a37c 88 #define ENCODEZ(n) { \
grzemich 0:d7bd7384a37c 89 if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \
grzemich 0:d7bd7384a37c 90 *cp++ = 0; \
grzemich 0:d7bd7384a37c 91 cp[1] = (u_char)(n); \
grzemich 0:d7bd7384a37c 92 cp[0] = (u_char)((n) >> 8); \
grzemich 0:d7bd7384a37c 93 cp += 2; \
grzemich 0:d7bd7384a37c 94 } else { \
grzemich 0:d7bd7384a37c 95 *cp++ = (u_char)(n); \
grzemich 0:d7bd7384a37c 96 } \
grzemich 0:d7bd7384a37c 97 }
grzemich 0:d7bd7384a37c 98
grzemich 0:d7bd7384a37c 99 #define DECODEL(f) { \
grzemich 0:d7bd7384a37c 100 if (*cp == 0) {\
grzemich 0:d7bd7384a37c 101 u32_t tmp = ntohl(f) + ((cp[1] << 8) | cp[2]); \
grzemich 0:d7bd7384a37c 102 (f) = htonl(tmp); \
grzemich 0:d7bd7384a37c 103 cp += 3; \
grzemich 0:d7bd7384a37c 104 } else { \
grzemich 0:d7bd7384a37c 105 u32_t tmp = ntohl(f) + (u32_t)*cp++; \
grzemich 0:d7bd7384a37c 106 (f) = htonl(tmp); \
grzemich 0:d7bd7384a37c 107 } \
grzemich 0:d7bd7384a37c 108 }
grzemich 0:d7bd7384a37c 109
grzemich 0:d7bd7384a37c 110 #define DECODES(f) { \
grzemich 0:d7bd7384a37c 111 if (*cp == 0) {\
grzemich 0:d7bd7384a37c 112 u_short tmp = ntohs(f) + (((u_short)cp[1] << 8) | cp[2]); \
grzemich 0:d7bd7384a37c 113 (f) = htons(tmp); \
grzemich 0:d7bd7384a37c 114 cp += 3; \
grzemich 0:d7bd7384a37c 115 } else { \
grzemich 0:d7bd7384a37c 116 u_short tmp = ntohs(f) + (u_short)*cp++; \
grzemich 0:d7bd7384a37c 117 (f) = htons(tmp); \
grzemich 0:d7bd7384a37c 118 } \
grzemich 0:d7bd7384a37c 119 }
grzemich 0:d7bd7384a37c 120
grzemich 0:d7bd7384a37c 121 #define DECODEU(f) { \
grzemich 0:d7bd7384a37c 122 if (*cp == 0) {\
grzemich 0:d7bd7384a37c 123 (f) = htons(((u_short)cp[1] << 8) | cp[2]); \
grzemich 0:d7bd7384a37c 124 cp += 3; \
grzemich 0:d7bd7384a37c 125 } else { \
grzemich 0:d7bd7384a37c 126 (f) = htons((u_short)*cp++); \
grzemich 0:d7bd7384a37c 127 } \
grzemich 0:d7bd7384a37c 128 }
grzemich 0:d7bd7384a37c 129
grzemich 0:d7bd7384a37c 130 /*
grzemich 0:d7bd7384a37c 131 * vj_compress_tcp - Attempt to do Van Jacobson header compression on a
grzemich 0:d7bd7384a37c 132 * packet. This assumes that nb and comp are not null and that the first
grzemich 0:d7bd7384a37c 133 * buffer of the chain contains a valid IP header.
grzemich 0:d7bd7384a37c 134 * Return the VJ type code indicating whether or not the packet was
grzemich 0:d7bd7384a37c 135 * compressed.
grzemich 0:d7bd7384a37c 136 */
grzemich 0:d7bd7384a37c 137 u_int
grzemich 0:d7bd7384a37c 138 vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
grzemich 0:d7bd7384a37c 139 {
grzemich 0:d7bd7384a37c 140 register struct ip_hdr *ip = (struct ip_hdr *)pb->payload;
grzemich 0:d7bd7384a37c 141 register struct cstate *cs = comp->last_cs->cs_next;
grzemich 0:d7bd7384a37c 142 register u_short hlen = IPH_HL(ip);
grzemich 0:d7bd7384a37c 143 register struct tcp_hdr *oth;
grzemich 0:d7bd7384a37c 144 register struct tcp_hdr *th;
grzemich 0:d7bd7384a37c 145 register u_short deltaS, deltaA;
grzemich 0:d7bd7384a37c 146 register u_long deltaL;
grzemich 0:d7bd7384a37c 147 register u_int changes = 0;
grzemich 0:d7bd7384a37c 148 u_char new_seq[16];
grzemich 0:d7bd7384a37c 149 register u_char *cp = new_seq;
grzemich 0:d7bd7384a37c 150
grzemich 0:d7bd7384a37c 151 /*
grzemich 0:d7bd7384a37c 152 * Check that the packet is IP proto TCP.
grzemich 0:d7bd7384a37c 153 */
grzemich 0:d7bd7384a37c 154 if (IPH_PROTO(ip) != IP_PROTO_TCP) {
grzemich 0:d7bd7384a37c 155 return (TYPE_IP);
grzemich 0:d7bd7384a37c 156 }
grzemich 0:d7bd7384a37c 157
grzemich 0:d7bd7384a37c 158 /*
grzemich 0:d7bd7384a37c 159 * Bail if this is an IP fragment or if the TCP packet isn't
grzemich 0:d7bd7384a37c 160 * `compressible' (i.e., ACK isn't set or some other control bit is
grzemich 0:d7bd7384a37c 161 * set).
grzemich 0:d7bd7384a37c 162 */
grzemich 0:d7bd7384a37c 163 if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || pb->tot_len < 40) {
grzemich 0:d7bd7384a37c 164 return (TYPE_IP);
grzemich 0:d7bd7384a37c 165 }
grzemich 0:d7bd7384a37c 166 th = (struct tcp_hdr *)&((long *)ip)[hlen];
grzemich 0:d7bd7384a37c 167 if ((TCPH_FLAGS(th) & (TCP_SYN|TCP_FIN|TCP_RST|TCP_ACK)) != TCP_ACK) {
grzemich 0:d7bd7384a37c 168 return (TYPE_IP);
grzemich 0:d7bd7384a37c 169 }
grzemich 0:d7bd7384a37c 170 /*
grzemich 0:d7bd7384a37c 171 * Packet is compressible -- we're going to send either a
grzemich 0:d7bd7384a37c 172 * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
grzemich 0:d7bd7384a37c 173 * to locate (or create) the connection state. Special case the
grzemich 0:d7bd7384a37c 174 * most recently used connection since it's most likely to be used
grzemich 0:d7bd7384a37c 175 * again & we don't have to do any reordering if it's used.
grzemich 0:d7bd7384a37c 176 */
grzemich 0:d7bd7384a37c 177 INCR(vjs_packets);
grzemich 0:d7bd7384a37c 178 if (!ip_addr_cmp(&ip->src, &cs->cs_ip.src)
grzemich 0:d7bd7384a37c 179 || !ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
grzemich 0:d7bd7384a37c 180 || *(long *)th != ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
grzemich 0:d7bd7384a37c 181 /*
grzemich 0:d7bd7384a37c 182 * Wasn't the first -- search for it.
grzemich 0:d7bd7384a37c 183 *
grzemich 0:d7bd7384a37c 184 * States are kept in a circularly linked list with
grzemich 0:d7bd7384a37c 185 * last_cs pointing to the end of the list. The
grzemich 0:d7bd7384a37c 186 * list is kept in lru order by moving a state to the
grzemich 0:d7bd7384a37c 187 * head of the list whenever it is referenced. Since
grzemich 0:d7bd7384a37c 188 * the list is short and, empirically, the connection
grzemich 0:d7bd7384a37c 189 * we want is almost always near the front, we locate
grzemich 0:d7bd7384a37c 190 * states via linear search. If we don't find a state
grzemich 0:d7bd7384a37c 191 * for the datagram, the oldest state is (re-)used.
grzemich 0:d7bd7384a37c 192 */
grzemich 0:d7bd7384a37c 193 register struct cstate *lcs;
grzemich 0:d7bd7384a37c 194 register struct cstate *lastcs = comp->last_cs;
grzemich 0:d7bd7384a37c 195
grzemich 0:d7bd7384a37c 196 do {
grzemich 0:d7bd7384a37c 197 lcs = cs; cs = cs->cs_next;
grzemich 0:d7bd7384a37c 198 INCR(vjs_searches);
grzemich 0:d7bd7384a37c 199 if (ip_addr_cmp(&ip->src, &cs->cs_ip.src)
grzemich 0:d7bd7384a37c 200 && ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
grzemich 0:d7bd7384a37c 201 && *(long *)th == ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
grzemich 0:d7bd7384a37c 202 goto found;
grzemich 0:d7bd7384a37c 203 }
grzemich 0:d7bd7384a37c 204 } while (cs != lastcs);
grzemich 0:d7bd7384a37c 205
grzemich 0:d7bd7384a37c 206 /*
grzemich 0:d7bd7384a37c 207 * Didn't find it -- re-use oldest cstate. Send an
grzemich 0:d7bd7384a37c 208 * uncompressed packet that tells the other side what
grzemich 0:d7bd7384a37c 209 * connection number we're using for this conversation.
grzemich 0:d7bd7384a37c 210 * Note that since the state list is circular, the oldest
grzemich 0:d7bd7384a37c 211 * state points to the newest and we only need to set
grzemich 0:d7bd7384a37c 212 * last_cs to update the lru linkage.
grzemich 0:d7bd7384a37c 213 */
grzemich 0:d7bd7384a37c 214 INCR(vjs_misses);
grzemich 0:d7bd7384a37c 215 comp->last_cs = lcs;
grzemich 0:d7bd7384a37c 216 hlen += TCPH_OFFSET(th);
grzemich 0:d7bd7384a37c 217 hlen <<= 2;
grzemich 0:d7bd7384a37c 218 /* Check that the IP/TCP headers are contained in the first buffer. */
grzemich 0:d7bd7384a37c 219 if (hlen > pb->len) {
grzemich 0:d7bd7384a37c 220 return (TYPE_IP);
grzemich 0:d7bd7384a37c 221 }
grzemich 0:d7bd7384a37c 222 goto uncompressed;
grzemich 0:d7bd7384a37c 223
grzemich 0:d7bd7384a37c 224 found:
grzemich 0:d7bd7384a37c 225 /*
grzemich 0:d7bd7384a37c 226 * Found it -- move to the front on the connection list.
grzemich 0:d7bd7384a37c 227 */
grzemich 0:d7bd7384a37c 228 if (cs == lastcs) {
grzemich 0:d7bd7384a37c 229 comp->last_cs = lcs;
grzemich 0:d7bd7384a37c 230 } else {
grzemich 0:d7bd7384a37c 231 lcs->cs_next = cs->cs_next;
grzemich 0:d7bd7384a37c 232 cs->cs_next = lastcs->cs_next;
grzemich 0:d7bd7384a37c 233 lastcs->cs_next = cs;
grzemich 0:d7bd7384a37c 234 }
grzemich 0:d7bd7384a37c 235 }
grzemich 0:d7bd7384a37c 236
grzemich 0:d7bd7384a37c 237 oth = (struct tcp_hdr *)&((long *)&cs->cs_ip)[hlen];
grzemich 0:d7bd7384a37c 238 deltaS = hlen;
grzemich 0:d7bd7384a37c 239 hlen += TCPH_OFFSET(th);
grzemich 0:d7bd7384a37c 240 hlen <<= 2;
grzemich 0:d7bd7384a37c 241 /* Check that the IP/TCP headers are contained in the first buffer. */
grzemich 0:d7bd7384a37c 242 if (hlen > pb->len) {
grzemich 0:d7bd7384a37c 243 PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
grzemich 0:d7bd7384a37c 244 return (TYPE_IP);
grzemich 0:d7bd7384a37c 245 }
grzemich 0:d7bd7384a37c 246
grzemich 0:d7bd7384a37c 247 /*
grzemich 0:d7bd7384a37c 248 * Make sure that only what we expect to change changed. The first
grzemich 0:d7bd7384a37c 249 * line of the `if' checks the IP protocol version, header length &
grzemich 0:d7bd7384a37c 250 * type of service. The 2nd line checks the "Don't fragment" bit.
grzemich 0:d7bd7384a37c 251 * The 3rd line checks the time-to-live and protocol (the protocol
grzemich 0:d7bd7384a37c 252 * check is unnecessary but costless). The 4th line checks the TCP
grzemich 0:d7bd7384a37c 253 * header length. The 5th line checks IP options, if any. The 6th
grzemich 0:d7bd7384a37c 254 * line checks TCP options, if any. If any of these things are
grzemich 0:d7bd7384a37c 255 * different between the previous & current datagram, we send the
grzemich 0:d7bd7384a37c 256 * current datagram `uncompressed'.
grzemich 0:d7bd7384a37c 257 */
grzemich 0:d7bd7384a37c 258 if (((u_short *)ip)[0] != ((u_short *)&cs->cs_ip)[0]
grzemich 0:d7bd7384a37c 259 || ((u_short *)ip)[3] != ((u_short *)&cs->cs_ip)[3]
grzemich 0:d7bd7384a37c 260 || ((u_short *)ip)[4] != ((u_short *)&cs->cs_ip)[4]
grzemich 0:d7bd7384a37c 261 || TCPH_OFFSET(th) != TCPH_OFFSET(oth)
grzemich 0:d7bd7384a37c 262 || (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2))
grzemich 0:d7bd7384a37c 263 || (TCPH_OFFSET(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_OFFSET(th) - 5) << 2))) {
grzemich 0:d7bd7384a37c 264 goto uncompressed;
grzemich 0:d7bd7384a37c 265 }
grzemich 0:d7bd7384a37c 266
grzemich 0:d7bd7384a37c 267 /*
grzemich 0:d7bd7384a37c 268 * Figure out which of the changing fields changed. The
grzemich 0:d7bd7384a37c 269 * receiver expects changes in the order: urgent, window,
grzemich 0:d7bd7384a37c 270 * ack, seq (the order minimizes the number of temporaries
grzemich 0:d7bd7384a37c 271 * needed in this section of code).
grzemich 0:d7bd7384a37c 272 */
grzemich 0:d7bd7384a37c 273 if (TCPH_FLAGS(th) & TCP_URG) {
grzemich 0:d7bd7384a37c 274 deltaS = ntohs(th->urgp);
grzemich 0:d7bd7384a37c 275 ENCODEZ(deltaS);
grzemich 0:d7bd7384a37c 276 changes |= NEW_U;
grzemich 0:d7bd7384a37c 277 } else if (th->urgp != oth->urgp) {
grzemich 0:d7bd7384a37c 278 /* argh! URG not set but urp changed -- a sensible
grzemich 0:d7bd7384a37c 279 * implementation should never do this but RFC793
grzemich 0:d7bd7384a37c 280 * doesn't prohibit the change so we have to deal
grzemich 0:d7bd7384a37c 281 * with it. */
grzemich 0:d7bd7384a37c 282 goto uncompressed;
grzemich 0:d7bd7384a37c 283 }
grzemich 0:d7bd7384a37c 284
grzemich 0:d7bd7384a37c 285 if ((deltaS = (u_short)(ntohs(th->wnd) - ntohs(oth->wnd))) != 0) {
grzemich 0:d7bd7384a37c 286 ENCODE(deltaS);
grzemich 0:d7bd7384a37c 287 changes |= NEW_W;
grzemich 0:d7bd7384a37c 288 }
grzemich 0:d7bd7384a37c 289
grzemich 0:d7bd7384a37c 290 if ((deltaL = ntohl(th->ackno) - ntohl(oth->ackno)) != 0) {
grzemich 0:d7bd7384a37c 291 if (deltaL > 0xffff) {
grzemich 0:d7bd7384a37c 292 goto uncompressed;
grzemich 0:d7bd7384a37c 293 }
grzemich 0:d7bd7384a37c 294 deltaA = (u_short)deltaL;
grzemich 0:d7bd7384a37c 295 ENCODE(deltaA);
grzemich 0:d7bd7384a37c 296 changes |= NEW_A;
grzemich 0:d7bd7384a37c 297 }
grzemich 0:d7bd7384a37c 298
grzemich 0:d7bd7384a37c 299 if ((deltaL = ntohl(th->seqno) - ntohl(oth->seqno)) != 0) {
grzemich 0:d7bd7384a37c 300 if (deltaL > 0xffff) {
grzemich 0:d7bd7384a37c 301 goto uncompressed;
grzemich 0:d7bd7384a37c 302 }
grzemich 0:d7bd7384a37c 303 deltaS = (u_short)deltaL;
grzemich 0:d7bd7384a37c 304 ENCODE(deltaS);
grzemich 0:d7bd7384a37c 305 changes |= NEW_S;
grzemich 0:d7bd7384a37c 306 }
grzemich 0:d7bd7384a37c 307
grzemich 0:d7bd7384a37c 308 switch(changes) {
grzemich 0:d7bd7384a37c 309 case 0:
grzemich 0:d7bd7384a37c 310 /*
grzemich 0:d7bd7384a37c 311 * Nothing changed. If this packet contains data and the
grzemich 0:d7bd7384a37c 312 * last one didn't, this is probably a data packet following
grzemich 0:d7bd7384a37c 313 * an ack (normal on an interactive connection) and we send
grzemich 0:d7bd7384a37c 314 * it compressed. Otherwise it's probably a retransmit,
grzemich 0:d7bd7384a37c 315 * retransmitted ack or window probe. Send it uncompressed
grzemich 0:d7bd7384a37c 316 * in case the other side missed the compressed version.
grzemich 0:d7bd7384a37c 317 */
grzemich 0:d7bd7384a37c 318 if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) &&
grzemich 0:d7bd7384a37c 319 ntohs(IPH_LEN(&cs->cs_ip)) == hlen) {
grzemich 0:d7bd7384a37c 320 break;
grzemich 0:d7bd7384a37c 321 }
grzemich 0:d7bd7384a37c 322
grzemich 0:d7bd7384a37c 323 /* (fall through) */
grzemich 0:d7bd7384a37c 324
grzemich 0:d7bd7384a37c 325 case SPECIAL_I:
grzemich 0:d7bd7384a37c 326 case SPECIAL_D:
grzemich 0:d7bd7384a37c 327 /*
grzemich 0:d7bd7384a37c 328 * actual changes match one of our special case encodings --
grzemich 0:d7bd7384a37c 329 * send packet uncompressed.
grzemich 0:d7bd7384a37c 330 */
grzemich 0:d7bd7384a37c 331 goto uncompressed;
grzemich 0:d7bd7384a37c 332
grzemich 0:d7bd7384a37c 333 case NEW_S|NEW_A:
grzemich 0:d7bd7384a37c 334 if (deltaS == deltaA && deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
grzemich 0:d7bd7384a37c 335 /* special case for echoed terminal traffic */
grzemich 0:d7bd7384a37c 336 changes = SPECIAL_I;
grzemich 0:d7bd7384a37c 337 cp = new_seq;
grzemich 0:d7bd7384a37c 338 }
grzemich 0:d7bd7384a37c 339 break;
grzemich 0:d7bd7384a37c 340
grzemich 0:d7bd7384a37c 341 case NEW_S:
grzemich 0:d7bd7384a37c 342 if (deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
grzemich 0:d7bd7384a37c 343 /* special case for data xfer */
grzemich 0:d7bd7384a37c 344 changes = SPECIAL_D;
grzemich 0:d7bd7384a37c 345 cp = new_seq;
grzemich 0:d7bd7384a37c 346 }
grzemich 0:d7bd7384a37c 347 break;
grzemich 0:d7bd7384a37c 348 }
grzemich 0:d7bd7384a37c 349
grzemich 0:d7bd7384a37c 350 deltaS = (u_short)(ntohs(IPH_ID(ip)) - ntohs(IPH_ID(&cs->cs_ip)));
grzemich 0:d7bd7384a37c 351 if (deltaS != 1) {
grzemich 0:d7bd7384a37c 352 ENCODEZ(deltaS);
grzemich 0:d7bd7384a37c 353 changes |= NEW_I;
grzemich 0:d7bd7384a37c 354 }
grzemich 0:d7bd7384a37c 355 if (TCPH_FLAGS(th) & TCP_PSH) {
grzemich 0:d7bd7384a37c 356 changes |= TCP_PUSH_BIT;
grzemich 0:d7bd7384a37c 357 }
grzemich 0:d7bd7384a37c 358 /*
grzemich 0:d7bd7384a37c 359 * Grab the cksum before we overwrite it below. Then update our
grzemich 0:d7bd7384a37c 360 * state with this packet's header.
grzemich 0:d7bd7384a37c 361 */
grzemich 0:d7bd7384a37c 362 deltaA = ntohs(th->chksum);
grzemich 0:d7bd7384a37c 363 BCOPY(ip, &cs->cs_ip, hlen);
grzemich 0:d7bd7384a37c 364
grzemich 0:d7bd7384a37c 365 /*
grzemich 0:d7bd7384a37c 366 * We want to use the original packet as our compressed packet.
grzemich 0:d7bd7384a37c 367 * (cp - new_seq) is the number of bytes we need for compressed
grzemich 0:d7bd7384a37c 368 * sequence numbers. In addition we need one byte for the change
grzemich 0:d7bd7384a37c 369 * mask, one for the connection id and two for the tcp checksum.
grzemich 0:d7bd7384a37c 370 * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how
grzemich 0:d7bd7384a37c 371 * many bytes of the original packet to toss so subtract the two to
grzemich 0:d7bd7384a37c 372 * get the new packet size.
grzemich 0:d7bd7384a37c 373 */
grzemich 0:d7bd7384a37c 374 deltaS = (u_short)(cp - new_seq);
grzemich 0:d7bd7384a37c 375 if (!comp->compressSlot || comp->last_xmit != cs->cs_id) {
grzemich 0:d7bd7384a37c 376 comp->last_xmit = cs->cs_id;
grzemich 0:d7bd7384a37c 377 hlen -= deltaS + 4;
grzemich 0:d7bd7384a37c 378 if(pbuf_header(pb, -hlen)){
grzemich 0:d7bd7384a37c 379 /* Can we cope with this failing? Just assert for now */
grzemich 0:d7bd7384a37c 380 LWIP_ASSERT("pbuf_header failed\n", 0);
grzemich 0:d7bd7384a37c 381 }
grzemich 0:d7bd7384a37c 382 cp = (u_char *)pb->payload;
grzemich 0:d7bd7384a37c 383 *cp++ = (u_char)(changes | NEW_C);
grzemich 0:d7bd7384a37c 384 *cp++ = cs->cs_id;
grzemich 0:d7bd7384a37c 385 } else {
grzemich 0:d7bd7384a37c 386 hlen -= deltaS + 3;
grzemich 0:d7bd7384a37c 387 if(pbuf_header(pb, -hlen)) {
grzemich 0:d7bd7384a37c 388 /* Can we cope with this failing? Just assert for now */
grzemich 0:d7bd7384a37c 389 LWIP_ASSERT("pbuf_header failed\n", 0);
grzemich 0:d7bd7384a37c 390 }
grzemich 0:d7bd7384a37c 391 cp = (u_char *)pb->payload;
grzemich 0:d7bd7384a37c 392 *cp++ = (u_char)changes;
grzemich 0:d7bd7384a37c 393 }
grzemich 0:d7bd7384a37c 394 *cp++ = (u_char)(deltaA >> 8);
grzemich 0:d7bd7384a37c 395 *cp++ = (u_char)deltaA;
grzemich 0:d7bd7384a37c 396 BCOPY(new_seq, cp, deltaS);
grzemich 0:d7bd7384a37c 397 INCR(vjs_compressed);
grzemich 0:d7bd7384a37c 398 return (TYPE_COMPRESSED_TCP);
grzemich 0:d7bd7384a37c 399
grzemich 0:d7bd7384a37c 400 /*
grzemich 0:d7bd7384a37c 401 * Update connection state cs & send uncompressed packet (that is,
grzemich 0:d7bd7384a37c 402 * a regular ip/tcp packet but with the 'conversation id' we hope
grzemich 0:d7bd7384a37c 403 * to use on future compressed packets in the protocol field).
grzemich 0:d7bd7384a37c 404 */
grzemich 0:d7bd7384a37c 405 uncompressed:
grzemich 0:d7bd7384a37c 406 BCOPY(ip, &cs->cs_ip, hlen);
grzemich 0:d7bd7384a37c 407 IPH_PROTO_SET(ip, cs->cs_id);
grzemich 0:d7bd7384a37c 408 comp->last_xmit = cs->cs_id;
grzemich 0:d7bd7384a37c 409 return (TYPE_UNCOMPRESSED_TCP);
grzemich 0:d7bd7384a37c 410 }
grzemich 0:d7bd7384a37c 411
grzemich 0:d7bd7384a37c 412 /*
grzemich 0:d7bd7384a37c 413 * Called when we may have missed a packet.
grzemich 0:d7bd7384a37c 414 */
grzemich 0:d7bd7384a37c 415 void
grzemich 0:d7bd7384a37c 416 vj_uncompress_err(struct vjcompress *comp)
grzemich 0:d7bd7384a37c 417 {
grzemich 0:d7bd7384a37c 418 comp->flags |= VJF_TOSS;
grzemich 0:d7bd7384a37c 419 INCR(vjs_errorin);
grzemich 0:d7bd7384a37c 420 }
grzemich 0:d7bd7384a37c 421
grzemich 0:d7bd7384a37c 422 /*
grzemich 0:d7bd7384a37c 423 * "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP.
grzemich 0:d7bd7384a37c 424 * Return 0 on success, -1 on failure.
grzemich 0:d7bd7384a37c 425 */
grzemich 0:d7bd7384a37c 426 int
grzemich 0:d7bd7384a37c 427 vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp)
grzemich 0:d7bd7384a37c 428 {
grzemich 0:d7bd7384a37c 429 register u_int hlen;
grzemich 0:d7bd7384a37c 430 register struct cstate *cs;
grzemich 0:d7bd7384a37c 431 register struct ip_hdr *ip;
grzemich 0:d7bd7384a37c 432
grzemich 0:d7bd7384a37c 433 ip = (struct ip_hdr *)nb->payload;
grzemich 0:d7bd7384a37c 434 hlen = IPH_HL(ip) << 2;
grzemich 0:d7bd7384a37c 435 if (IPH_PROTO(ip) >= MAX_SLOTS
grzemich 0:d7bd7384a37c 436 || hlen + sizeof(struct tcp_hdr) > nb->len
grzemich 0:d7bd7384a37c 437 || (hlen += TCPH_OFFSET(((struct tcp_hdr *)&((char *)ip)[hlen])) << 2)
grzemich 0:d7bd7384a37c 438 > nb->len
grzemich 0:d7bd7384a37c 439 || hlen > MAX_HDR) {
grzemich 0:d7bd7384a37c 440 PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n",
grzemich 0:d7bd7384a37c 441 IPH_PROTO(ip), hlen, nb->len));
grzemich 0:d7bd7384a37c 442 comp->flags |= VJF_TOSS;
grzemich 0:d7bd7384a37c 443 INCR(vjs_errorin);
grzemich 0:d7bd7384a37c 444 return -1;
grzemich 0:d7bd7384a37c 445 }
grzemich 0:d7bd7384a37c 446 cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)];
grzemich 0:d7bd7384a37c 447 comp->flags &=~ VJF_TOSS;
grzemich 0:d7bd7384a37c 448 IPH_PROTO_SET(ip, IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 449 BCOPY(ip, &cs->cs_ip, hlen);
grzemich 0:d7bd7384a37c 450 cs->cs_hlen = (u_short)hlen;
grzemich 0:d7bd7384a37c 451 INCR(vjs_uncompressedin);
grzemich 0:d7bd7384a37c 452 return 0;
grzemich 0:d7bd7384a37c 453 }
grzemich 0:d7bd7384a37c 454
grzemich 0:d7bd7384a37c 455 /*
grzemich 0:d7bd7384a37c 456 * Uncompress a packet of type TYPE_COMPRESSED_TCP.
grzemich 0:d7bd7384a37c 457 * The packet is composed of a buffer chain and the first buffer
grzemich 0:d7bd7384a37c 458 * must contain an accurate chain length.
grzemich 0:d7bd7384a37c 459 * The first buffer must include the entire compressed TCP/IP header.
grzemich 0:d7bd7384a37c 460 * This procedure replaces the compressed header with the uncompressed
grzemich 0:d7bd7384a37c 461 * header and returns the length of the VJ header.
grzemich 0:d7bd7384a37c 462 */
grzemich 0:d7bd7384a37c 463 int
grzemich 0:d7bd7384a37c 464 vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp)
grzemich 0:d7bd7384a37c 465 {
grzemich 0:d7bd7384a37c 466 u_char *cp;
grzemich 0:d7bd7384a37c 467 struct tcp_hdr *th;
grzemich 0:d7bd7384a37c 468 struct cstate *cs;
grzemich 0:d7bd7384a37c 469 u_short *bp;
grzemich 0:d7bd7384a37c 470 struct pbuf *n0 = *nb;
grzemich 0:d7bd7384a37c 471 u32_t tmp;
grzemich 0:d7bd7384a37c 472 u_int vjlen, hlen, changes;
grzemich 0:d7bd7384a37c 473
grzemich 0:d7bd7384a37c 474 INCR(vjs_compressedin);
grzemich 0:d7bd7384a37c 475 cp = (u_char *)n0->payload;
grzemich 0:d7bd7384a37c 476 changes = *cp++;
grzemich 0:d7bd7384a37c 477 if (changes & NEW_C) {
grzemich 0:d7bd7384a37c 478 /*
grzemich 0:d7bd7384a37c 479 * Make sure the state index is in range, then grab the state.
grzemich 0:d7bd7384a37c 480 * If we have a good state index, clear the 'discard' flag.
grzemich 0:d7bd7384a37c 481 */
grzemich 0:d7bd7384a37c 482 if (*cp >= MAX_SLOTS) {
grzemich 0:d7bd7384a37c 483 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp));
grzemich 0:d7bd7384a37c 484 goto bad;
grzemich 0:d7bd7384a37c 485 }
grzemich 0:d7bd7384a37c 486
grzemich 0:d7bd7384a37c 487 comp->flags &=~ VJF_TOSS;
grzemich 0:d7bd7384a37c 488 comp->last_recv = *cp++;
grzemich 0:d7bd7384a37c 489 } else {
grzemich 0:d7bd7384a37c 490 /*
grzemich 0:d7bd7384a37c 491 * this packet has an implicit state index. If we've
grzemich 0:d7bd7384a37c 492 * had a line error since the last time we got an
grzemich 0:d7bd7384a37c 493 * explicit state index, we have to toss the packet.
grzemich 0:d7bd7384a37c 494 */
grzemich 0:d7bd7384a37c 495 if (comp->flags & VJF_TOSS) {
grzemich 0:d7bd7384a37c 496 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n"));
grzemich 0:d7bd7384a37c 497 INCR(vjs_tossed);
grzemich 0:d7bd7384a37c 498 return (-1);
grzemich 0:d7bd7384a37c 499 }
grzemich 0:d7bd7384a37c 500 }
grzemich 0:d7bd7384a37c 501 cs = &comp->rstate[comp->last_recv];
grzemich 0:d7bd7384a37c 502 hlen = IPH_HL(&cs->cs_ip) << 2;
grzemich 0:d7bd7384a37c 503 th = (struct tcp_hdr *)&((u_char *)&cs->cs_ip)[hlen];
grzemich 0:d7bd7384a37c 504 th->chksum = htons((*cp << 8) | cp[1]);
grzemich 0:d7bd7384a37c 505 cp += 2;
grzemich 0:d7bd7384a37c 506 if (changes & TCP_PUSH_BIT) {
grzemich 0:d7bd7384a37c 507 TCPH_SET_FLAG(th, TCP_PSH);
grzemich 0:d7bd7384a37c 508 } else {
grzemich 0:d7bd7384a37c 509 TCPH_UNSET_FLAG(th, TCP_PSH);
grzemich 0:d7bd7384a37c 510 }
grzemich 0:d7bd7384a37c 511
grzemich 0:d7bd7384a37c 512 switch (changes & SPECIALS_MASK) {
grzemich 0:d7bd7384a37c 513 case SPECIAL_I:
grzemich 0:d7bd7384a37c 514 {
grzemich 0:d7bd7384a37c 515 register u32_t i = ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
grzemich 0:d7bd7384a37c 516 /* some compilers can't nest inline assembler.. */
grzemich 0:d7bd7384a37c 517 tmp = ntohl(th->ackno) + i;
grzemich 0:d7bd7384a37c 518 th->ackno = htonl(tmp);
grzemich 0:d7bd7384a37c 519 tmp = ntohl(th->seqno) + i;
grzemich 0:d7bd7384a37c 520 th->seqno = htonl(tmp);
grzemich 0:d7bd7384a37c 521 }
grzemich 0:d7bd7384a37c 522 break;
grzemich 0:d7bd7384a37c 523
grzemich 0:d7bd7384a37c 524 case SPECIAL_D:
grzemich 0:d7bd7384a37c 525 /* some compilers can't nest inline assembler.. */
grzemich 0:d7bd7384a37c 526 tmp = ntohl(th->seqno) + ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
grzemich 0:d7bd7384a37c 527 th->seqno = htonl(tmp);
grzemich 0:d7bd7384a37c 528 break;
grzemich 0:d7bd7384a37c 529
grzemich 0:d7bd7384a37c 530 default:
grzemich 0:d7bd7384a37c 531 if (changes & NEW_U) {
grzemich 0:d7bd7384a37c 532 TCPH_SET_FLAG(th, TCP_URG);
grzemich 0:d7bd7384a37c 533 DECODEU(th->urgp);
grzemich 0:d7bd7384a37c 534 } else {
grzemich 0:d7bd7384a37c 535 TCPH_UNSET_FLAG(th, TCP_URG);
grzemich 0:d7bd7384a37c 536 }
grzemich 0:d7bd7384a37c 537 if (changes & NEW_W) {
grzemich 0:d7bd7384a37c 538 DECODES(th->wnd);
grzemich 0:d7bd7384a37c 539 }
grzemich 0:d7bd7384a37c 540 if (changes & NEW_A) {
grzemich 0:d7bd7384a37c 541 DECODEL(th->ackno);
grzemich 0:d7bd7384a37c 542 }
grzemich 0:d7bd7384a37c 543 if (changes & NEW_S) {
grzemich 0:d7bd7384a37c 544 DECODEL(th->seqno);
grzemich 0:d7bd7384a37c 545 }
grzemich 0:d7bd7384a37c 546 break;
grzemich 0:d7bd7384a37c 547 }
grzemich 0:d7bd7384a37c 548 if (changes & NEW_I) {
grzemich 0:d7bd7384a37c 549 DECODES(cs->cs_ip._id);
grzemich 0:d7bd7384a37c 550 } else {
grzemich 0:d7bd7384a37c 551 IPH_ID_SET(&cs->cs_ip, ntohs(IPH_ID(&cs->cs_ip)) + 1);
grzemich 0:d7bd7384a37c 552 IPH_ID_SET(&cs->cs_ip, htons(IPH_ID(&cs->cs_ip)));
grzemich 0:d7bd7384a37c 553 }
grzemich 0:d7bd7384a37c 554
grzemich 0:d7bd7384a37c 555 /*
grzemich 0:d7bd7384a37c 556 * At this point, cp points to the first byte of data in the
grzemich 0:d7bd7384a37c 557 * packet. Fill in the IP total length and update the IP
grzemich 0:d7bd7384a37c 558 * header checksum.
grzemich 0:d7bd7384a37c 559 */
grzemich 0:d7bd7384a37c 560 vjlen = (u_short)(cp - (u_char*)n0->payload);
grzemich 0:d7bd7384a37c 561 if (n0->len < vjlen) {
grzemich 0:d7bd7384a37c 562 /*
grzemich 0:d7bd7384a37c 563 * We must have dropped some characters (crc should detect
grzemich 0:d7bd7384a37c 564 * this but the old slip framing won't)
grzemich 0:d7bd7384a37c 565 */
grzemich 0:d7bd7384a37c 566 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n",
grzemich 0:d7bd7384a37c 567 n0->len, vjlen));
grzemich 0:d7bd7384a37c 568 goto bad;
grzemich 0:d7bd7384a37c 569 }
grzemich 0:d7bd7384a37c 570
grzemich 0:d7bd7384a37c 571 #if BYTE_ORDER == LITTLE_ENDIAN
grzemich 0:d7bd7384a37c 572 tmp = n0->tot_len - vjlen + cs->cs_hlen;
grzemich 0:d7bd7384a37c 573 IPH_LEN_SET(&cs->cs_ip, htons((u_short)tmp));
grzemich 0:d7bd7384a37c 574 #else
grzemich 0:d7bd7384a37c 575 IPH_LEN_SET(&cs->cs_ip, htons(n0->tot_len - vjlen + cs->cs_hlen));
grzemich 0:d7bd7384a37c 576 #endif
grzemich 0:d7bd7384a37c 577
grzemich 0:d7bd7384a37c 578 /* recompute the ip header checksum */
grzemich 0:d7bd7384a37c 579 bp = (u_short *) &cs->cs_ip;
grzemich 0:d7bd7384a37c 580 IPH_CHKSUM_SET(&cs->cs_ip, 0);
grzemich 0:d7bd7384a37c 581 for (tmp = 0; hlen > 0; hlen -= 2) {
grzemich 0:d7bd7384a37c 582 tmp += *bp++;
grzemich 0:d7bd7384a37c 583 }
grzemich 0:d7bd7384a37c 584 tmp = (tmp & 0xffff) + (tmp >> 16);
grzemich 0:d7bd7384a37c 585 tmp = (tmp & 0xffff) + (tmp >> 16);
grzemich 0:d7bd7384a37c 586 IPH_CHKSUM_SET(&cs->cs_ip, (u_short)(~tmp));
grzemich 0:d7bd7384a37c 587
grzemich 0:d7bd7384a37c 588 /* Remove the compressed header and prepend the uncompressed header. */
grzemich 0:d7bd7384a37c 589 if(pbuf_header(n0, -((s16_t)(vjlen)))) {
grzemich 0:d7bd7384a37c 590 /* Can we cope with this failing? Just assert for now */
grzemich 0:d7bd7384a37c 591 LWIP_ASSERT("pbuf_header failed\n", 0);
grzemich 0:d7bd7384a37c 592 goto bad;
grzemich 0:d7bd7384a37c 593 }
grzemich 0:d7bd7384a37c 594
grzemich 0:d7bd7384a37c 595 if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) {
grzemich 0:d7bd7384a37c 596 struct pbuf *np, *q;
grzemich 0:d7bd7384a37c 597 u8_t *bufptr;
grzemich 0:d7bd7384a37c 598
grzemich 0:d7bd7384a37c 599 np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL);
grzemich 0:d7bd7384a37c 600 if(!np) {
grzemich 0:d7bd7384a37c 601 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n"));
grzemich 0:d7bd7384a37c 602 goto bad;
grzemich 0:d7bd7384a37c 603 }
grzemich 0:d7bd7384a37c 604
grzemich 0:d7bd7384a37c 605 if(pbuf_header(np, -cs->cs_hlen)) {
grzemich 0:d7bd7384a37c 606 /* Can we cope with this failing? Just assert for now */
grzemich 0:d7bd7384a37c 607 LWIP_ASSERT("pbuf_header failed\n", 0);
grzemich 0:d7bd7384a37c 608 goto bad;
grzemich 0:d7bd7384a37c 609 }
grzemich 0:d7bd7384a37c 610
grzemich 0:d7bd7384a37c 611 bufptr = n0->payload;
grzemich 0:d7bd7384a37c 612 for(q = np; q != NULL; q = q->next) {
grzemich 0:d7bd7384a37c 613 MEMCPY(q->payload, bufptr, q->len);
grzemich 0:d7bd7384a37c 614 bufptr += q->len;
grzemich 0:d7bd7384a37c 615 }
grzemich 0:d7bd7384a37c 616
grzemich 0:d7bd7384a37c 617 if(n0->next) {
grzemich 0:d7bd7384a37c 618 pbuf_chain(np, n0->next);
grzemich 0:d7bd7384a37c 619 pbuf_dechain(n0);
grzemich 0:d7bd7384a37c 620 }
grzemich 0:d7bd7384a37c 621 pbuf_free(n0);
grzemich 0:d7bd7384a37c 622 n0 = np;
grzemich 0:d7bd7384a37c 623 }
grzemich 0:d7bd7384a37c 624
grzemich 0:d7bd7384a37c 625 if(pbuf_header(n0, cs->cs_hlen)) {
grzemich 0:d7bd7384a37c 626 struct pbuf *np;
grzemich 0:d7bd7384a37c 627
grzemich 0:d7bd7384a37c 628 LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE);
grzemich 0:d7bd7384a37c 629 np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL);
grzemich 0:d7bd7384a37c 630 if(!np) {
grzemich 0:d7bd7384a37c 631 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n"));
grzemich 0:d7bd7384a37c 632 goto bad;
grzemich 0:d7bd7384a37c 633 }
grzemich 0:d7bd7384a37c 634 pbuf_cat(np, n0);
grzemich 0:d7bd7384a37c 635 n0 = np;
grzemich 0:d7bd7384a37c 636 }
grzemich 0:d7bd7384a37c 637 LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen);
grzemich 0:d7bd7384a37c 638 MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen);
grzemich 0:d7bd7384a37c 639
grzemich 0:d7bd7384a37c 640 *nb = n0;
grzemich 0:d7bd7384a37c 641
grzemich 0:d7bd7384a37c 642 return vjlen;
grzemich 0:d7bd7384a37c 643
grzemich 0:d7bd7384a37c 644 bad:
grzemich 0:d7bd7384a37c 645 comp->flags |= VJF_TOSS;
grzemich 0:d7bd7384a37c 646 INCR(vjs_errorin);
grzemich 0:d7bd7384a37c 647 return (-1);
grzemich 0:d7bd7384a37c 648 }
grzemich 0:d7bd7384a37c 649
grzemich 0:d7bd7384a37c 650 #endif /* VJ_SUPPORT */
grzemich 0:d7bd7384a37c 651
grzemich 0:d7bd7384a37c 652 #endif /* PPP_SUPPORT */