Yihui Xiong / lwip-arch-max-dev

dev

Dependents:   EthernetInterface

Fork of lwip by mbed official

netif/ppp/vj.c@19:6c91d95ef874, 2015-03-02 (annotated)

Committer:
yihui
Date:
Mon Mar 02 08:19:15 2015 +0000
Revision:
19:6c91d95ef874
Parent:
0:51ac1d130fd4 
minor changes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:51ac1d130fd4 1 /*
mbed_official 0:51ac1d130fd4 2 * Routines to compress and uncompess tcp packets (for transmission
mbed_official 0:51ac1d130fd4 3 * over low speed serial lines.
mbed_official 0:51ac1d130fd4 4 *
mbed_official 0:51ac1d130fd4 5 * Copyright (c) 1989 Regents of the University of California.
mbed_official 0:51ac1d130fd4 6 * All rights reserved.
mbed_official 0:51ac1d130fd4 7 *
mbed_official 0:51ac1d130fd4 8 * Redistribution and use in source and binary forms are permitted
mbed_official 0:51ac1d130fd4 9 * provided that the above copyright notice and this paragraph are
mbed_official 0:51ac1d130fd4 10 * duplicated in all such forms and that any documentation,
mbed_official 0:51ac1d130fd4 11 * advertising materials, and other materials related to such
mbed_official 0:51ac1d130fd4 12 * distribution and use acknowledge that the software was developed
mbed_official 0:51ac1d130fd4 13 * by the University of California, Berkeley. The name of the
mbed_official 0:51ac1d130fd4 14 * University may not be used to endorse or promote products derived
mbed_official 0:51ac1d130fd4 15 * from this software without specific prior written permission.
mbed_official 0:51ac1d130fd4 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
mbed_official 0:51ac1d130fd4 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
mbed_official 0:51ac1d130fd4 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
mbed_official 0:51ac1d130fd4 19 *
mbed_official 0:51ac1d130fd4 20 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
mbed_official 0:51ac1d130fd4 21 * Initial distribution.
mbed_official 0:51ac1d130fd4 22 *
mbed_official 0:51ac1d130fd4 23 * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au,
mbed_official 0:51ac1d130fd4 24 * so that the entire packet being decompressed doesn't have
mbed_official 0:51ac1d130fd4 25 * to be in contiguous memory (just the compressed header).
mbed_official 0:51ac1d130fd4 26 *
mbed_official 0:51ac1d130fd4 27 * Modified March 1998 by Guy Lancaster, glanca@gesn.com,
mbed_official 0:51ac1d130fd4 28 * for a 16 bit processor.
mbed_official 0:51ac1d130fd4 29 */
mbed_official 0:51ac1d130fd4 30
mbed_official 0:51ac1d130fd4 31 #include "lwip/opt.h"
mbed_official 0:51ac1d130fd4 32
mbed_official 0:51ac1d130fd4 33 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
mbed_official 0:51ac1d130fd4 34
mbed_official 0:51ac1d130fd4 35 #include "ppp.h"
mbed_official 0:51ac1d130fd4 36 #include "pppdebug.h"
mbed_official 0:51ac1d130fd4 37
mbed_official 0:51ac1d130fd4 38 #include "vj.h"
mbed_official 0:51ac1d130fd4 39
mbed_official 0:51ac1d130fd4 40 #include <string.h>
mbed_official 0:51ac1d130fd4 41
mbed_official 0:51ac1d130fd4 42 #if VJ_SUPPORT
mbed_official 0:51ac1d130fd4 43
mbed_official 0:51ac1d130fd4 44 #if LINK_STATS
mbed_official 0:51ac1d130fd4 45 #define INCR(counter) ++comp->stats.counter
mbed_official 0:51ac1d130fd4 46 #else
mbed_official 0:51ac1d130fd4 47 #define INCR(counter)
mbed_official 0:51ac1d130fd4 48 #endif
mbed_official 0:51ac1d130fd4 49
mbed_official 0:51ac1d130fd4 50 void
mbed_official 0:51ac1d130fd4 51 vj_compress_init(struct vjcompress *comp)
mbed_official 0:51ac1d130fd4 52 {
mbed_official 0:51ac1d130fd4 53 register u_char i;
mbed_official 0:51ac1d130fd4 54 register struct cstate *tstate = comp->tstate;
mbed_official 0:51ac1d130fd4 55
mbed_official 0:51ac1d130fd4 56 #if MAX_SLOTS == 0
mbed_official 0:51ac1d130fd4 57 memset((char *)comp, 0, sizeof(*comp));
mbed_official 0:51ac1d130fd4 58 #endif
mbed_official 0:51ac1d130fd4 59 comp->maxSlotIndex = MAX_SLOTS - 1;
mbed_official 0:51ac1d130fd4 60 comp->compressSlot = 0; /* Disable slot ID compression by default. */
mbed_official 0:51ac1d130fd4 61 for (i = MAX_SLOTS - 1; i > 0; --i) {
mbed_official 0:51ac1d130fd4 62 tstate[i].cs_id = i;
mbed_official 0:51ac1d130fd4 63 tstate[i].cs_next = &tstate[i - 1];
mbed_official 0:51ac1d130fd4 64 }
mbed_official 0:51ac1d130fd4 65 tstate[0].cs_next = &tstate[MAX_SLOTS - 1];
mbed_official 0:51ac1d130fd4 66 tstate[0].cs_id = 0;
mbed_official 0:51ac1d130fd4 67 comp->last_cs = &tstate[0];
mbed_official 0:51ac1d130fd4 68 comp->last_recv = 255;
mbed_official 0:51ac1d130fd4 69 comp->last_xmit = 255;
mbed_official 0:51ac1d130fd4 70 comp->flags = VJF_TOSS;
mbed_official 0:51ac1d130fd4 71 }
mbed_official 0:51ac1d130fd4 72
mbed_official 0:51ac1d130fd4 73
mbed_official 0:51ac1d130fd4 74 /* ENCODE encodes a number that is known to be non-zero. ENCODEZ
mbed_official 0:51ac1d130fd4 75 * checks for zero (since zero has to be encoded in the long, 3 byte
mbed_official 0:51ac1d130fd4 76 * form).
mbed_official 0:51ac1d130fd4 77 */
mbed_official 0:51ac1d130fd4 78 #define ENCODE(n) { \
mbed_official 0:51ac1d130fd4 79 if ((u_short)(n) >= 256) { \
mbed_official 0:51ac1d130fd4 80 *cp++ = 0; \
mbed_official 0:51ac1d130fd4 81 cp[1] = (u_char)(n); \
mbed_official 0:51ac1d130fd4 82 cp[0] = (u_char)((n) >> 8); \
mbed_official 0:51ac1d130fd4 83 cp += 2; \
mbed_official 0:51ac1d130fd4 84 } else { \
mbed_official 0:51ac1d130fd4 85 *cp++ = (u_char)(n); \
mbed_official 0:51ac1d130fd4 86 } \
mbed_official 0:51ac1d130fd4 87 }
mbed_official 0:51ac1d130fd4 88 #define ENCODEZ(n) { \
mbed_official 0:51ac1d130fd4 89 if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \
mbed_official 0:51ac1d130fd4 90 *cp++ = 0; \
mbed_official 0:51ac1d130fd4 91 cp[1] = (u_char)(n); \
mbed_official 0:51ac1d130fd4 92 cp[0] = (u_char)((n) >> 8); \
mbed_official 0:51ac1d130fd4 93 cp += 2; \
mbed_official 0:51ac1d130fd4 94 } else { \
mbed_official 0:51ac1d130fd4 95 *cp++ = (u_char)(n); \
mbed_official 0:51ac1d130fd4 96 } \
mbed_official 0:51ac1d130fd4 97 }
mbed_official 0:51ac1d130fd4 98
mbed_official 0:51ac1d130fd4 99 #define DECODEL(f) { \
mbed_official 0:51ac1d130fd4 100 if (*cp == 0) {\
mbed_official 0:51ac1d130fd4 101 u32_t tmp = ntohl(f) + ((cp[1] << 8) | cp[2]); \
mbed_official 0:51ac1d130fd4 102 (f) = htonl(tmp); \
mbed_official 0:51ac1d130fd4 103 cp += 3; \
mbed_official 0:51ac1d130fd4 104 } else { \
mbed_official 0:51ac1d130fd4 105 u32_t tmp = ntohl(f) + (u32_t)*cp++; \
mbed_official 0:51ac1d130fd4 106 (f) = htonl(tmp); \
mbed_official 0:51ac1d130fd4 107 } \
mbed_official 0:51ac1d130fd4 108 }
mbed_official 0:51ac1d130fd4 109
mbed_official 0:51ac1d130fd4 110 #define DECODES(f) { \
mbed_official 0:51ac1d130fd4 111 if (*cp == 0) {\
mbed_official 0:51ac1d130fd4 112 u_short tmp = ntohs(f) + (((u_short)cp[1] << 8) | cp[2]); \
mbed_official 0:51ac1d130fd4 113 (f) = htons(tmp); \
mbed_official 0:51ac1d130fd4 114 cp += 3; \
mbed_official 0:51ac1d130fd4 115 } else { \
mbed_official 0:51ac1d130fd4 116 u_short tmp = ntohs(f) + (u_short)*cp++; \
mbed_official 0:51ac1d130fd4 117 (f) = htons(tmp); \
mbed_official 0:51ac1d130fd4 118 } \
mbed_official 0:51ac1d130fd4 119 }
mbed_official 0:51ac1d130fd4 120
mbed_official 0:51ac1d130fd4 121 #define DECODEU(f) { \
mbed_official 0:51ac1d130fd4 122 if (*cp == 0) {\
mbed_official 0:51ac1d130fd4 123 (f) = htons(((u_short)cp[1] << 8) | cp[2]); \
mbed_official 0:51ac1d130fd4 124 cp += 3; \
mbed_official 0:51ac1d130fd4 125 } else { \
mbed_official 0:51ac1d130fd4 126 (f) = htons((u_short)*cp++); \
mbed_official 0:51ac1d130fd4 127 } \
mbed_official 0:51ac1d130fd4 128 }
mbed_official 0:51ac1d130fd4 129
mbed_official 0:51ac1d130fd4 130 /*
mbed_official 0:51ac1d130fd4 131 * vj_compress_tcp - Attempt to do Van Jacobson header compression on a
mbed_official 0:51ac1d130fd4 132 * packet. This assumes that nb and comp are not null and that the first
mbed_official 0:51ac1d130fd4 133 * buffer of the chain contains a valid IP header.
mbed_official 0:51ac1d130fd4 134 * Return the VJ type code indicating whether or not the packet was
mbed_official 0:51ac1d130fd4 135 * compressed.
mbed_official 0:51ac1d130fd4 136 */
mbed_official 0:51ac1d130fd4 137 u_int
mbed_official 0:51ac1d130fd4 138 vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
mbed_official 0:51ac1d130fd4 139 {
mbed_official 0:51ac1d130fd4 140 register struct ip_hdr *ip = (struct ip_hdr *)pb->payload;
mbed_official 0:51ac1d130fd4 141 register struct cstate *cs = comp->last_cs->cs_next;
mbed_official 0:51ac1d130fd4 142 register u_short hlen = IPH_HL(ip);
mbed_official 0:51ac1d130fd4 143 register struct tcp_hdr *oth;
mbed_official 0:51ac1d130fd4 144 register struct tcp_hdr *th;
mbed_official 0:51ac1d130fd4 145 register u_short deltaS, deltaA;
mbed_official 0:51ac1d130fd4 146 register u_long deltaL;
mbed_official 0:51ac1d130fd4 147 register u_int changes = 0;
mbed_official 0:51ac1d130fd4 148 u_char new_seq[16];
mbed_official 0:51ac1d130fd4 149 register u_char *cp = new_seq;
mbed_official 0:51ac1d130fd4 150
mbed_official 0:51ac1d130fd4 151 /*
mbed_official 0:51ac1d130fd4 152 * Check that the packet is IP proto TCP.
mbed_official 0:51ac1d130fd4 153 */
mbed_official 0:51ac1d130fd4 154 if (IPH_PROTO(ip) != IP_PROTO_TCP) {
mbed_official 0:51ac1d130fd4 155 return (TYPE_IP);
mbed_official 0:51ac1d130fd4 156 }
mbed_official 0:51ac1d130fd4 157
mbed_official 0:51ac1d130fd4 158 /*
mbed_official 0:51ac1d130fd4 159 * Bail if this is an IP fragment or if the TCP packet isn't
mbed_official 0:51ac1d130fd4 160 * `compressible' (i.e., ACK isn't set or some other control bit is
mbed_official 0:51ac1d130fd4 161 * set).
mbed_official 0:51ac1d130fd4 162 */
mbed_official 0:51ac1d130fd4 163 if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || pb->tot_len < 40) {
mbed_official 0:51ac1d130fd4 164 return (TYPE_IP);
mbed_official 0:51ac1d130fd4 165 }
mbed_official 0:51ac1d130fd4 166 th = (struct tcp_hdr *)&((long *)ip)[hlen];
mbed_official 0:51ac1d130fd4 167 if ((TCPH_FLAGS(th) & (TCP_SYN|TCP_FIN|TCP_RST|TCP_ACK)) != TCP_ACK) {
mbed_official 0:51ac1d130fd4 168 return (TYPE_IP);
mbed_official 0:51ac1d130fd4 169 }
mbed_official 0:51ac1d130fd4 170 /*
mbed_official 0:51ac1d130fd4 171 * Packet is compressible -- we're going to send either a
mbed_official 0:51ac1d130fd4 172 * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
mbed_official 0:51ac1d130fd4 173 * to locate (or create) the connection state. Special case the
mbed_official 0:51ac1d130fd4 174 * most recently used connection since it's most likely to be used
mbed_official 0:51ac1d130fd4 175 * again & we don't have to do any reordering if it's used.
mbed_official 0:51ac1d130fd4 176 */
mbed_official 0:51ac1d130fd4 177 INCR(vjs_packets);
mbed_official 0:51ac1d130fd4 178 if (!ip_addr_cmp(&ip->src, &cs->cs_ip.src)
mbed_official 0:51ac1d130fd4 179 || !ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
mbed_official 0:51ac1d130fd4 180 || *(long *)th != ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
mbed_official 0:51ac1d130fd4 181 /*
mbed_official 0:51ac1d130fd4 182 * Wasn't the first -- search for it.
mbed_official 0:51ac1d130fd4 183 *
mbed_official 0:51ac1d130fd4 184 * States are kept in a circularly linked list with
mbed_official 0:51ac1d130fd4 185 * last_cs pointing to the end of the list. The
mbed_official 0:51ac1d130fd4 186 * list is kept in lru order by moving a state to the
mbed_official 0:51ac1d130fd4 187 * head of the list whenever it is referenced. Since
mbed_official 0:51ac1d130fd4 188 * the list is short and, empirically, the connection
mbed_official 0:51ac1d130fd4 189 * we want is almost always near the front, we locate
mbed_official 0:51ac1d130fd4 190 * states via linear search. If we don't find a state
mbed_official 0:51ac1d130fd4 191 * for the datagram, the oldest state is (re-)used.
mbed_official 0:51ac1d130fd4 192 */
mbed_official 0:51ac1d130fd4 193 register struct cstate *lcs;
mbed_official 0:51ac1d130fd4 194 register struct cstate *lastcs = comp->last_cs;
mbed_official 0:51ac1d130fd4 195
mbed_official 0:51ac1d130fd4 196 do {
mbed_official 0:51ac1d130fd4 197 lcs = cs; cs = cs->cs_next;
mbed_official 0:51ac1d130fd4 198 INCR(vjs_searches);
mbed_official 0:51ac1d130fd4 199 if (ip_addr_cmp(&ip->src, &cs->cs_ip.src)
mbed_official 0:51ac1d130fd4 200 && ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
mbed_official 0:51ac1d130fd4 201 && *(long *)th == ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
mbed_official 0:51ac1d130fd4 202 goto found;
mbed_official 0:51ac1d130fd4 203 }
mbed_official 0:51ac1d130fd4 204 } while (cs != lastcs);
mbed_official 0:51ac1d130fd4 205
mbed_official 0:51ac1d130fd4 206 /*
mbed_official 0:51ac1d130fd4 207 * Didn't find it -- re-use oldest cstate. Send an
mbed_official 0:51ac1d130fd4 208 * uncompressed packet that tells the other side what
mbed_official 0:51ac1d130fd4 209 * connection number we're using for this conversation.
mbed_official 0:51ac1d130fd4 210 * Note that since the state list is circular, the oldest
mbed_official 0:51ac1d130fd4 211 * state points to the newest and we only need to set
mbed_official 0:51ac1d130fd4 212 * last_cs to update the lru linkage.
mbed_official 0:51ac1d130fd4 213 */
mbed_official 0:51ac1d130fd4 214 INCR(vjs_misses);
mbed_official 0:51ac1d130fd4 215 comp->last_cs = lcs;
mbed_official 0:51ac1d130fd4 216 hlen += TCPH_OFFSET(th);
mbed_official 0:51ac1d130fd4 217 hlen <<= 2;
mbed_official 0:51ac1d130fd4 218 /* Check that the IP/TCP headers are contained in the first buffer. */
mbed_official 0:51ac1d130fd4 219 if (hlen > pb->len) {
mbed_official 0:51ac1d130fd4 220 return (TYPE_IP);
mbed_official 0:51ac1d130fd4 221 }
mbed_official 0:51ac1d130fd4 222 goto uncompressed;
mbed_official 0:51ac1d130fd4 223
mbed_official 0:51ac1d130fd4 224 found:
mbed_official 0:51ac1d130fd4 225 /*
mbed_official 0:51ac1d130fd4 226 * Found it -- move to the front on the connection list.
mbed_official 0:51ac1d130fd4 227 */
mbed_official 0:51ac1d130fd4 228 if (cs == lastcs) {
mbed_official 0:51ac1d130fd4 229 comp->last_cs = lcs;
mbed_official 0:51ac1d130fd4 230 } else {
mbed_official 0:51ac1d130fd4 231 lcs->cs_next = cs->cs_next;
mbed_official 0:51ac1d130fd4 232 cs->cs_next = lastcs->cs_next;
mbed_official 0:51ac1d130fd4 233 lastcs->cs_next = cs;
mbed_official 0:51ac1d130fd4 234 }
mbed_official 0:51ac1d130fd4 235 }
mbed_official 0:51ac1d130fd4 236
mbed_official 0:51ac1d130fd4 237 oth = (struct tcp_hdr *)&((long *)&cs->cs_ip)[hlen];
mbed_official 0:51ac1d130fd4 238 deltaS = hlen;
mbed_official 0:51ac1d130fd4 239 hlen += TCPH_OFFSET(th);
mbed_official 0:51ac1d130fd4 240 hlen <<= 2;
mbed_official 0:51ac1d130fd4 241 /* Check that the IP/TCP headers are contained in the first buffer. */
mbed_official 0:51ac1d130fd4 242 if (hlen > pb->len) {
mbed_official 0:51ac1d130fd4 243 PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
mbed_official 0:51ac1d130fd4 244 return (TYPE_IP);
mbed_official 0:51ac1d130fd4 245 }
mbed_official 0:51ac1d130fd4 246
mbed_official 0:51ac1d130fd4 247 /*
mbed_official 0:51ac1d130fd4 248 * Make sure that only what we expect to change changed. The first
mbed_official 0:51ac1d130fd4 249 * line of the `if' checks the IP protocol version, header length &
mbed_official 0:51ac1d130fd4 250 * type of service. The 2nd line checks the "Don't fragment" bit.
mbed_official 0:51ac1d130fd4 251 * The 3rd line checks the time-to-live and protocol (the protocol
mbed_official 0:51ac1d130fd4 252 * check is unnecessary but costless). The 4th line checks the TCP
mbed_official 0:51ac1d130fd4 253 * header length. The 5th line checks IP options, if any. The 6th
mbed_official 0:51ac1d130fd4 254 * line checks TCP options, if any. If any of these things are
mbed_official 0:51ac1d130fd4 255 * different between the previous & current datagram, we send the
mbed_official 0:51ac1d130fd4 256 * current datagram `uncompressed'.
mbed_official 0:51ac1d130fd4 257 */
mbed_official 0:51ac1d130fd4 258 if (((u_short *)ip)[0] != ((u_short *)&cs->cs_ip)[0]
mbed_official 0:51ac1d130fd4 259 || ((u_short *)ip)[3] != ((u_short *)&cs->cs_ip)[3]
mbed_official 0:51ac1d130fd4 260 || ((u_short *)ip)[4] != ((u_short *)&cs->cs_ip)[4]
mbed_official 0:51ac1d130fd4 261 || TCPH_OFFSET(th) != TCPH_OFFSET(oth)
mbed_official 0:51ac1d130fd4 262 || (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2))
mbed_official 0:51ac1d130fd4 263 || (TCPH_OFFSET(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_OFFSET(th) - 5) << 2))) {
mbed_official 0:51ac1d130fd4 264 goto uncompressed;
mbed_official 0:51ac1d130fd4 265 }
mbed_official 0:51ac1d130fd4 266
mbed_official 0:51ac1d130fd4 267 /*
mbed_official 0:51ac1d130fd4 268 * Figure out which of the changing fields changed. The
mbed_official 0:51ac1d130fd4 269 * receiver expects changes in the order: urgent, window,
mbed_official 0:51ac1d130fd4 270 * ack, seq (the order minimizes the number of temporaries
mbed_official 0:51ac1d130fd4 271 * needed in this section of code).
mbed_official 0:51ac1d130fd4 272 */
mbed_official 0:51ac1d130fd4 273 if (TCPH_FLAGS(th) & TCP_URG) {
mbed_official 0:51ac1d130fd4 274 deltaS = ntohs(th->urgp);
mbed_official 0:51ac1d130fd4 275 ENCODEZ(deltaS);
mbed_official 0:51ac1d130fd4 276 changes |= NEW_U;
mbed_official 0:51ac1d130fd4 277 } else if (th->urgp != oth->urgp) {
mbed_official 0:51ac1d130fd4 278 /* argh! URG not set but urp changed -- a sensible
mbed_official 0:51ac1d130fd4 279 * implementation should never do this but RFC793
mbed_official 0:51ac1d130fd4 280 * doesn't prohibit the change so we have to deal
mbed_official 0:51ac1d130fd4 281 * with it. */
mbed_official 0:51ac1d130fd4 282 goto uncompressed;
mbed_official 0:51ac1d130fd4 283 }
mbed_official 0:51ac1d130fd4 284
mbed_official 0:51ac1d130fd4 285 if ((deltaS = (u_short)(ntohs(th->wnd) - ntohs(oth->wnd))) != 0) {
mbed_official 0:51ac1d130fd4 286 ENCODE(deltaS);
mbed_official 0:51ac1d130fd4 287 changes |= NEW_W;
mbed_official 0:51ac1d130fd4 288 }
mbed_official 0:51ac1d130fd4 289
mbed_official 0:51ac1d130fd4 290 if ((deltaL = ntohl(th->ackno) - ntohl(oth->ackno)) != 0) {
mbed_official 0:51ac1d130fd4 291 if (deltaL > 0xffff) {
mbed_official 0:51ac1d130fd4 292 goto uncompressed;
mbed_official 0:51ac1d130fd4 293 }
mbed_official 0:51ac1d130fd4 294 deltaA = (u_short)deltaL;
mbed_official 0:51ac1d130fd4 295 ENCODE(deltaA);
mbed_official 0:51ac1d130fd4 296 changes |= NEW_A;
mbed_official 0:51ac1d130fd4 297 }
mbed_official 0:51ac1d130fd4 298
mbed_official 0:51ac1d130fd4 299 if ((deltaL = ntohl(th->seqno) - ntohl(oth->seqno)) != 0) {
mbed_official 0:51ac1d130fd4 300 if (deltaL > 0xffff) {
mbed_official 0:51ac1d130fd4 301 goto uncompressed;
mbed_official 0:51ac1d130fd4 302 }
mbed_official 0:51ac1d130fd4 303 deltaS = (u_short)deltaL;
mbed_official 0:51ac1d130fd4 304 ENCODE(deltaS);
mbed_official 0:51ac1d130fd4 305 changes |= NEW_S;
mbed_official 0:51ac1d130fd4 306 }
mbed_official 0:51ac1d130fd4 307
mbed_official 0:51ac1d130fd4 308 switch(changes) {
mbed_official 0:51ac1d130fd4 309 case 0:
mbed_official 0:51ac1d130fd4 310 /*
mbed_official 0:51ac1d130fd4 311 * Nothing changed. If this packet contains data and the
mbed_official 0:51ac1d130fd4 312 * last one didn't, this is probably a data packet following
mbed_official 0:51ac1d130fd4 313 * an ack (normal on an interactive connection) and we send
mbed_official 0:51ac1d130fd4 314 * it compressed. Otherwise it's probably a retransmit,
mbed_official 0:51ac1d130fd4 315 * retransmitted ack or window probe. Send it uncompressed
mbed_official 0:51ac1d130fd4 316 * in case the other side missed the compressed version.
mbed_official 0:51ac1d130fd4 317 */
mbed_official 0:51ac1d130fd4 318 if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) &&
mbed_official 0:51ac1d130fd4 319 ntohs(IPH_LEN(&cs->cs_ip)) == hlen) {
mbed_official 0:51ac1d130fd4 320 break;
mbed_official 0:51ac1d130fd4 321 }
mbed_official 0:51ac1d130fd4 322
mbed_official 0:51ac1d130fd4 323 /* (fall through) */
mbed_official 0:51ac1d130fd4 324
mbed_official 0:51ac1d130fd4 325 case SPECIAL_I:
mbed_official 0:51ac1d130fd4 326 case SPECIAL_D:
mbed_official 0:51ac1d130fd4 327 /*
mbed_official 0:51ac1d130fd4 328 * actual changes match one of our special case encodings --
mbed_official 0:51ac1d130fd4 329 * send packet uncompressed.
mbed_official 0:51ac1d130fd4 330 */
mbed_official 0:51ac1d130fd4 331 goto uncompressed;
mbed_official 0:51ac1d130fd4 332
mbed_official 0:51ac1d130fd4 333 case NEW_S|NEW_A:
mbed_official 0:51ac1d130fd4 334 if (deltaS == deltaA && deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
mbed_official 0:51ac1d130fd4 335 /* special case for echoed terminal traffic */
mbed_official 0:51ac1d130fd4 336 changes = SPECIAL_I;
mbed_official 0:51ac1d130fd4 337 cp = new_seq;
mbed_official 0:51ac1d130fd4 338 }
mbed_official 0:51ac1d130fd4 339 break;
mbed_official 0:51ac1d130fd4 340
mbed_official 0:51ac1d130fd4 341 case NEW_S:
mbed_official 0:51ac1d130fd4 342 if (deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
mbed_official 0:51ac1d130fd4 343 /* special case for data xfer */
mbed_official 0:51ac1d130fd4 344 changes = SPECIAL_D;
mbed_official 0:51ac1d130fd4 345 cp = new_seq;
mbed_official 0:51ac1d130fd4 346 }
mbed_official 0:51ac1d130fd4 347 break;
mbed_official 0:51ac1d130fd4 348 }
mbed_official 0:51ac1d130fd4 349
mbed_official 0:51ac1d130fd4 350 deltaS = (u_short)(ntohs(IPH_ID(ip)) - ntohs(IPH_ID(&cs->cs_ip)));
mbed_official 0:51ac1d130fd4 351 if (deltaS != 1) {
mbed_official 0:51ac1d130fd4 352 ENCODEZ(deltaS);
mbed_official 0:51ac1d130fd4 353 changes |= NEW_I;
mbed_official 0:51ac1d130fd4 354 }
mbed_official 0:51ac1d130fd4 355 if (TCPH_FLAGS(th) & TCP_PSH) {
mbed_official 0:51ac1d130fd4 356 changes |= TCP_PUSH_BIT;
mbed_official 0:51ac1d130fd4 357 }
mbed_official 0:51ac1d130fd4 358 /*
mbed_official 0:51ac1d130fd4 359 * Grab the cksum before we overwrite it below. Then update our
mbed_official 0:51ac1d130fd4 360 * state with this packet's header.
mbed_official 0:51ac1d130fd4 361 */
mbed_official 0:51ac1d130fd4 362 deltaA = ntohs(th->chksum);
mbed_official 0:51ac1d130fd4 363 BCOPY(ip, &cs->cs_ip, hlen);
mbed_official 0:51ac1d130fd4 364
mbed_official 0:51ac1d130fd4 365 /*
mbed_official 0:51ac1d130fd4 366 * We want to use the original packet as our compressed packet.
mbed_official 0:51ac1d130fd4 367 * (cp - new_seq) is the number of bytes we need for compressed
mbed_official 0:51ac1d130fd4 368 * sequence numbers. In addition we need one byte for the change
mbed_official 0:51ac1d130fd4 369 * mask, one for the connection id and two for the tcp checksum.
mbed_official 0:51ac1d130fd4 370 * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how
mbed_official 0:51ac1d130fd4 371 * many bytes of the original packet to toss so subtract the two to
mbed_official 0:51ac1d130fd4 372 * get the new packet size.
mbed_official 0:51ac1d130fd4 373 */
mbed_official 0:51ac1d130fd4 374 deltaS = (u_short)(cp - new_seq);
mbed_official 0:51ac1d130fd4 375 if (!comp->compressSlot || comp->last_xmit != cs->cs_id) {
mbed_official 0:51ac1d130fd4 376 comp->last_xmit = cs->cs_id;
mbed_official 0:51ac1d130fd4 377 hlen -= deltaS + 4;
mbed_official 0:51ac1d130fd4 378 if(pbuf_header(pb, -hlen)){
mbed_official 0:51ac1d130fd4 379 /* Can we cope with this failing? Just assert for now */
mbed_official 0:51ac1d130fd4 380 LWIP_ASSERT("pbuf_header failed\n", 0);
mbed_official 0:51ac1d130fd4 381 }
mbed_official 0:51ac1d130fd4 382 cp = (u_char *)pb->payload;
mbed_official 0:51ac1d130fd4 383 *cp++ = (u_char)(changes | NEW_C);
mbed_official 0:51ac1d130fd4 384 *cp++ = cs->cs_id;
mbed_official 0:51ac1d130fd4 385 } else {
mbed_official 0:51ac1d130fd4 386 hlen -= deltaS + 3;
mbed_official 0:51ac1d130fd4 387 if(pbuf_header(pb, -hlen)) {
mbed_official 0:51ac1d130fd4 388 /* Can we cope with this failing? Just assert for now */
mbed_official 0:51ac1d130fd4 389 LWIP_ASSERT("pbuf_header failed\n", 0);
mbed_official 0:51ac1d130fd4 390 }
mbed_official 0:51ac1d130fd4 391 cp = (u_char *)pb->payload;
mbed_official 0:51ac1d130fd4 392 *cp++ = (u_char)changes;
mbed_official 0:51ac1d130fd4 393 }
mbed_official 0:51ac1d130fd4 394 *cp++ = (u_char)(deltaA >> 8);
mbed_official 0:51ac1d130fd4 395 *cp++ = (u_char)deltaA;
mbed_official 0:51ac1d130fd4 396 BCOPY(new_seq, cp, deltaS);
mbed_official 0:51ac1d130fd4 397 INCR(vjs_compressed);
mbed_official 0:51ac1d130fd4 398 return (TYPE_COMPRESSED_TCP);
mbed_official 0:51ac1d130fd4 399
mbed_official 0:51ac1d130fd4 400 /*
mbed_official 0:51ac1d130fd4 401 * Update connection state cs & send uncompressed packet (that is,
mbed_official 0:51ac1d130fd4 402 * a regular ip/tcp packet but with the 'conversation id' we hope
mbed_official 0:51ac1d130fd4 403 * to use on future compressed packets in the protocol field).
mbed_official 0:51ac1d130fd4 404 */
mbed_official 0:51ac1d130fd4 405 uncompressed:
mbed_official 0:51ac1d130fd4 406 BCOPY(ip, &cs->cs_ip, hlen);
mbed_official 0:51ac1d130fd4 407 IPH_PROTO_SET(ip, cs->cs_id);
mbed_official 0:51ac1d130fd4 408 comp->last_xmit = cs->cs_id;
mbed_official 0:51ac1d130fd4 409 return (TYPE_UNCOMPRESSED_TCP);
mbed_official 0:51ac1d130fd4 410 }
mbed_official 0:51ac1d130fd4 411
mbed_official 0:51ac1d130fd4 412 /*
mbed_official 0:51ac1d130fd4 413 * Called when we may have missed a packet.
mbed_official 0:51ac1d130fd4 414 */
mbed_official 0:51ac1d130fd4 415 void
mbed_official 0:51ac1d130fd4 416 vj_uncompress_err(struct vjcompress *comp)
mbed_official 0:51ac1d130fd4 417 {
mbed_official 0:51ac1d130fd4 418 comp->flags |= VJF_TOSS;
mbed_official 0:51ac1d130fd4 419 INCR(vjs_errorin);
mbed_official 0:51ac1d130fd4 420 }
mbed_official 0:51ac1d130fd4 421
mbed_official 0:51ac1d130fd4 422 /*
mbed_official 0:51ac1d130fd4 423 * "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP.
mbed_official 0:51ac1d130fd4 424 * Return 0 on success, -1 on failure.
mbed_official 0:51ac1d130fd4 425 */
mbed_official 0:51ac1d130fd4 426 int
mbed_official 0:51ac1d130fd4 427 vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp)
mbed_official 0:51ac1d130fd4 428 {
mbed_official 0:51ac1d130fd4 429 register u_int hlen;
mbed_official 0:51ac1d130fd4 430 register struct cstate *cs;
mbed_official 0:51ac1d130fd4 431 register struct ip_hdr *ip;
mbed_official 0:51ac1d130fd4 432
mbed_official 0:51ac1d130fd4 433 ip = (struct ip_hdr *)nb->payload;
mbed_official 0:51ac1d130fd4 434 hlen = IPH_HL(ip) << 2;
mbed_official 0:51ac1d130fd4 435 if (IPH_PROTO(ip) >= MAX_SLOTS
mbed_official 0:51ac1d130fd4 436 || hlen + sizeof(struct tcp_hdr) > nb->len
mbed_official 0:51ac1d130fd4 437 || (hlen += TCPH_OFFSET(((struct tcp_hdr *)&((char *)ip)[hlen])) << 2)
mbed_official 0:51ac1d130fd4 438 > nb->len
mbed_official 0:51ac1d130fd4 439 || hlen > MAX_HDR) {
mbed_official 0:51ac1d130fd4 440 PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n",
mbed_official 0:51ac1d130fd4 441 IPH_PROTO(ip), hlen, nb->len));
mbed_official 0:51ac1d130fd4 442 comp->flags |= VJF_TOSS;
mbed_official 0:51ac1d130fd4 443 INCR(vjs_errorin);
mbed_official 0:51ac1d130fd4 444 return -1;
mbed_official 0:51ac1d130fd4 445 }
mbed_official 0:51ac1d130fd4 446 cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)];
mbed_official 0:51ac1d130fd4 447 comp->flags &=~ VJF_TOSS;
mbed_official 0:51ac1d130fd4 448 IPH_PROTO_SET(ip, IP_PROTO_TCP);
mbed_official 0:51ac1d130fd4 449 BCOPY(ip, &cs->cs_ip, hlen);
mbed_official 0:51ac1d130fd4 450 cs->cs_hlen = (u_short)hlen;
mbed_official 0:51ac1d130fd4 451 INCR(vjs_uncompressedin);
mbed_official 0:51ac1d130fd4 452 return 0;
mbed_official 0:51ac1d130fd4 453 }
mbed_official 0:51ac1d130fd4 454
mbed_official 0:51ac1d130fd4 455 /*
mbed_official 0:51ac1d130fd4 456 * Uncompress a packet of type TYPE_COMPRESSED_TCP.
mbed_official 0:51ac1d130fd4 457 * The packet is composed of a buffer chain and the first buffer
mbed_official 0:51ac1d130fd4 458 * must contain an accurate chain length.
mbed_official 0:51ac1d130fd4 459 * The first buffer must include the entire compressed TCP/IP header.
mbed_official 0:51ac1d130fd4 460 * This procedure replaces the compressed header with the uncompressed
mbed_official 0:51ac1d130fd4 461 * header and returns the length of the VJ header.
mbed_official 0:51ac1d130fd4 462 */
mbed_official 0:51ac1d130fd4 463 int
mbed_official 0:51ac1d130fd4 464 vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp)
mbed_official 0:51ac1d130fd4 465 {
mbed_official 0:51ac1d130fd4 466 u_char *cp;
mbed_official 0:51ac1d130fd4 467 struct tcp_hdr *th;
mbed_official 0:51ac1d130fd4 468 struct cstate *cs;
mbed_official 0:51ac1d130fd4 469 u_short *bp;
mbed_official 0:51ac1d130fd4 470 struct pbuf *n0 = *nb;
mbed_official 0:51ac1d130fd4 471 u32_t tmp;
mbed_official 0:51ac1d130fd4 472 u_int vjlen, hlen, changes;
mbed_official 0:51ac1d130fd4 473
mbed_official 0:51ac1d130fd4 474 INCR(vjs_compressedin);
mbed_official 0:51ac1d130fd4 475 cp = (u_char *)n0->payload;
mbed_official 0:51ac1d130fd4 476 changes = *cp++;
mbed_official 0:51ac1d130fd4 477 if (changes & NEW_C) {
mbed_official 0:51ac1d130fd4 478 /*
mbed_official 0:51ac1d130fd4 479 * Make sure the state index is in range, then grab the state.
mbed_official 0:51ac1d130fd4 480 * If we have a good state index, clear the 'discard' flag.
mbed_official 0:51ac1d130fd4 481 */
mbed_official 0:51ac1d130fd4 482 if (*cp >= MAX_SLOTS) {
mbed_official 0:51ac1d130fd4 483 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp));
mbed_official 0:51ac1d130fd4 484 goto bad;
mbed_official 0:51ac1d130fd4 485 }
mbed_official 0:51ac1d130fd4 486
mbed_official 0:51ac1d130fd4 487 comp->flags &=~ VJF_TOSS;
mbed_official 0:51ac1d130fd4 488 comp->last_recv = *cp++;
mbed_official 0:51ac1d130fd4 489 } else {
mbed_official 0:51ac1d130fd4 490 /*
mbed_official 0:51ac1d130fd4 491 * this packet has an implicit state index. If we've
mbed_official 0:51ac1d130fd4 492 * had a line error since the last time we got an
mbed_official 0:51ac1d130fd4 493 * explicit state index, we have to toss the packet.
mbed_official 0:51ac1d130fd4 494 */
mbed_official 0:51ac1d130fd4 495 if (comp->flags & VJF_TOSS) {
mbed_official 0:51ac1d130fd4 496 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n"));
mbed_official 0:51ac1d130fd4 497 INCR(vjs_tossed);
mbed_official 0:51ac1d130fd4 498 return (-1);
mbed_official 0:51ac1d130fd4 499 }
mbed_official 0:51ac1d130fd4 500 }
mbed_official 0:51ac1d130fd4 501 cs = &comp->rstate[comp->last_recv];
mbed_official 0:51ac1d130fd4 502 hlen = IPH_HL(&cs->cs_ip) << 2;
mbed_official 0:51ac1d130fd4 503 th = (struct tcp_hdr *)&((u_char *)&cs->cs_ip)[hlen];
mbed_official 0:51ac1d130fd4 504 th->chksum = htons((*cp << 8) | cp[1]);
mbed_official 0:51ac1d130fd4 505 cp += 2;
mbed_official 0:51ac1d130fd4 506 if (changes & TCP_PUSH_BIT) {
mbed_official 0:51ac1d130fd4 507 TCPH_SET_FLAG(th, TCP_PSH);
mbed_official 0:51ac1d130fd4 508 } else {
mbed_official 0:51ac1d130fd4 509 TCPH_UNSET_FLAG(th, TCP_PSH);
mbed_official 0:51ac1d130fd4 510 }
mbed_official 0:51ac1d130fd4 511
mbed_official 0:51ac1d130fd4 512 switch (changes & SPECIALS_MASK) {
mbed_official 0:51ac1d130fd4 513 case SPECIAL_I:
mbed_official 0:51ac1d130fd4 514 {
mbed_official 0:51ac1d130fd4 515 register u32_t i = ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
mbed_official 0:51ac1d130fd4 516 /* some compilers can't nest inline assembler.. */
mbed_official 0:51ac1d130fd4 517 tmp = ntohl(th->ackno) + i;
mbed_official 0:51ac1d130fd4 518 th->ackno = htonl(tmp);
mbed_official 0:51ac1d130fd4 519 tmp = ntohl(th->seqno) + i;
mbed_official 0:51ac1d130fd4 520 th->seqno = htonl(tmp);
mbed_official 0:51ac1d130fd4 521 }
mbed_official 0:51ac1d130fd4 522 break;
mbed_official 0:51ac1d130fd4 523
mbed_official 0:51ac1d130fd4 524 case SPECIAL_D:
mbed_official 0:51ac1d130fd4 525 /* some compilers can't nest inline assembler.. */
mbed_official 0:51ac1d130fd4 526 tmp = ntohl(th->seqno) + ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
mbed_official 0:51ac1d130fd4 527 th->seqno = htonl(tmp);
mbed_official 0:51ac1d130fd4 528 break;
mbed_official 0:51ac1d130fd4 529
mbed_official 0:51ac1d130fd4 530 default:
mbed_official 0:51ac1d130fd4 531 if (changes & NEW_U) {
mbed_official 0:51ac1d130fd4 532 TCPH_SET_FLAG(th, TCP_URG);
mbed_official 0:51ac1d130fd4 533 DECODEU(th->urgp);
mbed_official 0:51ac1d130fd4 534 } else {
mbed_official 0:51ac1d130fd4 535 TCPH_UNSET_FLAG(th, TCP_URG);
mbed_official 0:51ac1d130fd4 536 }
mbed_official 0:51ac1d130fd4 537 if (changes & NEW_W) {
mbed_official 0:51ac1d130fd4 538 DECODES(th->wnd);
mbed_official 0:51ac1d130fd4 539 }
mbed_official 0:51ac1d130fd4 540 if (changes & NEW_A) {
mbed_official 0:51ac1d130fd4 541 DECODEL(th->ackno);
mbed_official 0:51ac1d130fd4 542 }
mbed_official 0:51ac1d130fd4 543 if (changes & NEW_S) {
mbed_official 0:51ac1d130fd4 544 DECODEL(th->seqno);
mbed_official 0:51ac1d130fd4 545 }
mbed_official 0:51ac1d130fd4 546 break;
mbed_official 0:51ac1d130fd4 547 }
mbed_official 0:51ac1d130fd4 548 if (changes & NEW_I) {
mbed_official 0:51ac1d130fd4 549 DECODES(cs->cs_ip._id);
mbed_official 0:51ac1d130fd4 550 } else {
mbed_official 0:51ac1d130fd4 551 IPH_ID_SET(&cs->cs_ip, ntohs(IPH_ID(&cs->cs_ip)) + 1);
mbed_official 0:51ac1d130fd4 552 IPH_ID_SET(&cs->cs_ip, htons(IPH_ID(&cs->cs_ip)));
mbed_official 0:51ac1d130fd4 553 }
mbed_official 0:51ac1d130fd4 554
mbed_official 0:51ac1d130fd4 555 /*
mbed_official 0:51ac1d130fd4 556 * At this point, cp points to the first byte of data in the
mbed_official 0:51ac1d130fd4 557 * packet. Fill in the IP total length and update the IP
mbed_official 0:51ac1d130fd4 558 * header checksum.
mbed_official 0:51ac1d130fd4 559 */
mbed_official 0:51ac1d130fd4 560 vjlen = (u_short)(cp - (u_char*)n0->payload);
mbed_official 0:51ac1d130fd4 561 if (n0->len < vjlen) {
mbed_official 0:51ac1d130fd4 562 /*
mbed_official 0:51ac1d130fd4 563 * We must have dropped some characters (crc should detect
mbed_official 0:51ac1d130fd4 564 * this but the old slip framing won't)
mbed_official 0:51ac1d130fd4 565 */
mbed_official 0:51ac1d130fd4 566 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n",
mbed_official 0:51ac1d130fd4 567 n0->len, vjlen));
mbed_official 0:51ac1d130fd4 568 goto bad;
mbed_official 0:51ac1d130fd4 569 }
mbed_official 0:51ac1d130fd4 570
mbed_official 0:51ac1d130fd4 571 #if BYTE_ORDER == LITTLE_ENDIAN
mbed_official 0:51ac1d130fd4 572 tmp = n0->tot_len - vjlen + cs->cs_hlen;
mbed_official 0:51ac1d130fd4 573 IPH_LEN_SET(&cs->cs_ip, htons((u_short)tmp));
mbed_official 0:51ac1d130fd4 574 #else
mbed_official 0:51ac1d130fd4 575 IPH_LEN_SET(&cs->cs_ip, htons(n0->tot_len - vjlen + cs->cs_hlen));
mbed_official 0:51ac1d130fd4 576 #endif
mbed_official 0:51ac1d130fd4 577
mbed_official 0:51ac1d130fd4 578 /* recompute the ip header checksum */
mbed_official 0:51ac1d130fd4 579 bp = (u_short *) &cs->cs_ip;
mbed_official 0:51ac1d130fd4 580 IPH_CHKSUM_SET(&cs->cs_ip, 0);
mbed_official 0:51ac1d130fd4 581 for (tmp = 0; hlen > 0; hlen -= 2) {
mbed_official 0:51ac1d130fd4 582 tmp += *bp++;
mbed_official 0:51ac1d130fd4 583 }
mbed_official 0:51ac1d130fd4 584 tmp = (tmp & 0xffff) + (tmp >> 16);
mbed_official 0:51ac1d130fd4 585 tmp = (tmp & 0xffff) + (tmp >> 16);
mbed_official 0:51ac1d130fd4 586 IPH_CHKSUM_SET(&cs->cs_ip, (u_short)(~tmp));
mbed_official 0:51ac1d130fd4 587
mbed_official 0:51ac1d130fd4 588 /* Remove the compressed header and prepend the uncompressed header. */
mbed_official 0:51ac1d130fd4 589 if(pbuf_header(n0, -((s16_t)(vjlen)))) {
mbed_official 0:51ac1d130fd4 590 /* Can we cope with this failing? Just assert for now */
mbed_official 0:51ac1d130fd4 591 LWIP_ASSERT("pbuf_header failed\n", 0);
mbed_official 0:51ac1d130fd4 592 goto bad;
mbed_official 0:51ac1d130fd4 593 }
mbed_official 0:51ac1d130fd4 594
mbed_official 0:51ac1d130fd4 595 if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) {
mbed_official 0:51ac1d130fd4 596 struct pbuf *np, *q;
mbed_official 0:51ac1d130fd4 597 u8_t *bufptr;
mbed_official 0:51ac1d130fd4 598
mbed_official 0:51ac1d130fd4 599 np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL);
mbed_official 0:51ac1d130fd4 600 if(!np) {
mbed_official 0:51ac1d130fd4 601 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n"));
mbed_official 0:51ac1d130fd4 602 goto bad;
mbed_official 0:51ac1d130fd4 603 }
mbed_official 0:51ac1d130fd4 604
mbed_official 0:51ac1d130fd4 605 if(pbuf_header(np, -cs->cs_hlen)) {
mbed_official 0:51ac1d130fd4 606 /* Can we cope with this failing? Just assert for now */
mbed_official 0:51ac1d130fd4 607 LWIP_ASSERT("pbuf_header failed\n", 0);
mbed_official 0:51ac1d130fd4 608 goto bad;
mbed_official 0:51ac1d130fd4 609 }
mbed_official 0:51ac1d130fd4 610
mbed_official 0:51ac1d130fd4 611 bufptr = n0->payload;
mbed_official 0:51ac1d130fd4 612 for(q = np; q != NULL; q = q->next) {
mbed_official 0:51ac1d130fd4 613 MEMCPY(q->payload, bufptr, q->len);
mbed_official 0:51ac1d130fd4 614 bufptr += q->len;
mbed_official 0:51ac1d130fd4 615 }
mbed_official 0:51ac1d130fd4 616
mbed_official 0:51ac1d130fd4 617 if(n0->next) {
mbed_official 0:51ac1d130fd4 618 pbuf_chain(np, n0->next);
mbed_official 0:51ac1d130fd4 619 pbuf_dechain(n0);
mbed_official 0:51ac1d130fd4 620 }
mbed_official 0:51ac1d130fd4 621 pbuf_free(n0);
mbed_official 0:51ac1d130fd4 622 n0 = np;
mbed_official 0:51ac1d130fd4 623 }
mbed_official 0:51ac1d130fd4 624
mbed_official 0:51ac1d130fd4 625 if(pbuf_header(n0, cs->cs_hlen)) {
mbed_official 0:51ac1d130fd4 626 struct pbuf *np;
mbed_official 0:51ac1d130fd4 627
mbed_official 0:51ac1d130fd4 628 LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE);
mbed_official 0:51ac1d130fd4 629 np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL);
mbed_official 0:51ac1d130fd4 630 if(!np) {
mbed_official 0:51ac1d130fd4 631 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n"));
mbed_official 0:51ac1d130fd4 632 goto bad;
mbed_official 0:51ac1d130fd4 633 }
mbed_official 0:51ac1d130fd4 634 pbuf_cat(np, n0);
mbed_official 0:51ac1d130fd4 635 n0 = np;
mbed_official 0:51ac1d130fd4 636 }
mbed_official 0:51ac1d130fd4 637 LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen);
mbed_official 0:51ac1d130fd4 638 MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen);
mbed_official 0:51ac1d130fd4 639
mbed_official 0:51ac1d130fd4 640 *nb = n0;
mbed_official 0:51ac1d130fd4 641
mbed_official 0:51ac1d130fd4 642 return vjlen;
mbed_official 0:51ac1d130fd4 643
mbed_official 0:51ac1d130fd4 644 bad:
mbed_official 0:51ac1d130fd4 645 comp->flags |= VJF_TOSS;
mbed_official 0:51ac1d130fd4 646 INCR(vjs_errorin);
mbed_official 0:51ac1d130fd4 647 return (-1);
mbed_official 0:51ac1d130fd4 648 }
mbed_official 0:51ac1d130fd4 649
mbed_official 0:51ac1d130fd4 650 #endif /* VJ_SUPPORT */
mbed_official 0:51ac1d130fd4 651
mbed_official 0:51ac1d130fd4 652 #endif /* PPP_SUPPORT */