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Dependencies:   mbed

NetServices/lwip/netif/ppp/vj.c@1:f5ac63519541, 2014-03-05 (annotated)

Committer:
Michael J. Spencer
Date:
Wed Mar 05 06:14:02 2014 -0800
Revision:
1:f5ac63519541
Initial commit.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Michael J. Spencer 1:f5ac63519541 1 /*
Michael J. Spencer 1:f5ac63519541 2 * Routines to compress and uncompess tcp packets (for transmission
Michael J. Spencer 1:f5ac63519541 3 * over low speed serial lines.
Michael J. Spencer 1:f5ac63519541 4 *
Michael J. Spencer 1:f5ac63519541 5 * Copyright (c) 1989 Regents of the University of California.
Michael J. Spencer 1:f5ac63519541 6 * All rights reserved.
Michael J. Spencer 1:f5ac63519541 7 *
Michael J. Spencer 1:f5ac63519541 8 * Redistribution and use in source and binary forms are permitted
Michael J. Spencer 1:f5ac63519541 9 * provided that the above copyright notice and this paragraph are
Michael J. Spencer 1:f5ac63519541 10 * duplicated in all such forms and that any documentation,
Michael J. Spencer 1:f5ac63519541 11 * advertising materials, and other materials related to such
Michael J. Spencer 1:f5ac63519541 12 * distribution and use acknowledge that the software was developed
Michael J. Spencer 1:f5ac63519541 13 * by the University of California, Berkeley. The name of the
Michael J. Spencer 1:f5ac63519541 14 * University may not be used to endorse or promote products derived
Michael J. Spencer 1:f5ac63519541 15 * from this software without specific prior written permission.
Michael J. Spencer 1:f5ac63519541 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
Michael J. Spencer 1:f5ac63519541 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
Michael J. Spencer 1:f5ac63519541 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Michael J. Spencer 1:f5ac63519541 19 *
Michael J. Spencer 1:f5ac63519541 20 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
Michael J. Spencer 1:f5ac63519541 21 * Initial distribution.
Michael J. Spencer 1:f5ac63519541 22 *
Michael J. Spencer 1:f5ac63519541 23 * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au,
Michael J. Spencer 1:f5ac63519541 24 * so that the entire packet being decompressed doesn't have
Michael J. Spencer 1:f5ac63519541 25 * to be in contiguous memory (just the compressed header).
Michael J. Spencer 1:f5ac63519541 26 *
Michael J. Spencer 1:f5ac63519541 27 * Modified March 1998 by Guy Lancaster, glanca@gesn.com,
Michael J. Spencer 1:f5ac63519541 28 * for a 16 bit processor.
Michael J. Spencer 1:f5ac63519541 29 */
Michael J. Spencer 1:f5ac63519541 30
Michael J. Spencer 1:f5ac63519541 31 #include "lwip/opt.h"
Michael J. Spencer 1:f5ac63519541 32
Michael J. Spencer 1:f5ac63519541 33 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
Michael J. Spencer 1:f5ac63519541 34
Michael J. Spencer 1:f5ac63519541 35 #include "ppp.h"
Michael J. Spencer 1:f5ac63519541 36 #include "pppdebug.h"
Michael J. Spencer 1:f5ac63519541 37
Michael J. Spencer 1:f5ac63519541 38 #include "vj.h"
Michael J. Spencer 1:f5ac63519541 39
Michael J. Spencer 1:f5ac63519541 40 #include <string.h>
Michael J. Spencer 1:f5ac63519541 41
Michael J. Spencer 1:f5ac63519541 42 #if VJ_SUPPORT
Michael J. Spencer 1:f5ac63519541 43
Michael J. Spencer 1:f5ac63519541 44 #if LINK_STATS
Michael J. Spencer 1:f5ac63519541 45 #define INCR(counter) ++comp->stats.counter
Michael J. Spencer 1:f5ac63519541 46 #else
Michael J. Spencer 1:f5ac63519541 47 #define INCR(counter)
Michael J. Spencer 1:f5ac63519541 48 #endif
Michael J. Spencer 1:f5ac63519541 49
Michael J. Spencer 1:f5ac63519541 50 void
Michael J. Spencer 1:f5ac63519541 51 vj_compress_init(struct vjcompress *comp)
Michael J. Spencer 1:f5ac63519541 52 {
Michael J. Spencer 1:f5ac63519541 53 register u_char i;
Michael J. Spencer 1:f5ac63519541 54 register struct cstate *tstate = comp->tstate;
Michael J. Spencer 1:f5ac63519541 55
Michael J. Spencer 1:f5ac63519541 56 #if MAX_SLOTS == 0
Michael J. Spencer 1:f5ac63519541 57 memset((char *)comp, 0, sizeof(*comp));
Michael J. Spencer 1:f5ac63519541 58 #endif
Michael J. Spencer 1:f5ac63519541 59 comp->maxSlotIndex = MAX_SLOTS - 1;
Michael J. Spencer 1:f5ac63519541 60 comp->compressSlot = 0; /* Disable slot ID compression by default. */
Michael J. Spencer 1:f5ac63519541 61 for (i = MAX_SLOTS - 1; i > 0; --i) {
Michael J. Spencer 1:f5ac63519541 62 tstate[i].cs_id = i;
Michael J. Spencer 1:f5ac63519541 63 tstate[i].cs_next = &tstate[i - 1];
Michael J. Spencer 1:f5ac63519541 64 }
Michael J. Spencer 1:f5ac63519541 65 tstate[0].cs_next = &tstate[MAX_SLOTS - 1];
Michael J. Spencer 1:f5ac63519541 66 tstate[0].cs_id = 0;
Michael J. Spencer 1:f5ac63519541 67 comp->last_cs = &tstate[0];
Michael J. Spencer 1:f5ac63519541 68 comp->last_recv = 255;
Michael J. Spencer 1:f5ac63519541 69 comp->last_xmit = 255;
Michael J. Spencer 1:f5ac63519541 70 comp->flags = VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 71 }
Michael J. Spencer 1:f5ac63519541 72
Michael J. Spencer 1:f5ac63519541 73
Michael J. Spencer 1:f5ac63519541 74 /* ENCODE encodes a number that is known to be non-zero. ENCODEZ
Michael J. Spencer 1:f5ac63519541 75 * checks for zero (since zero has to be encoded in the long, 3 byte
Michael J. Spencer 1:f5ac63519541 76 * form).
Michael J. Spencer 1:f5ac63519541 77 */
Michael J. Spencer 1:f5ac63519541 78 #define ENCODE(n) { \
Michael J. Spencer 1:f5ac63519541 79 if ((u_short)(n) >= 256) { \
Michael J. Spencer 1:f5ac63519541 80 *cp++ = 0; \
Michael J. Spencer 1:f5ac63519541 81 cp[1] = (u_char)(n); \
Michael J. Spencer 1:f5ac63519541 82 cp[0] = (u_char)((n) >> 8); \
Michael J. Spencer 1:f5ac63519541 83 cp += 2; \
Michael J. Spencer 1:f5ac63519541 84 } else { \
Michael J. Spencer 1:f5ac63519541 85 *cp++ = (u_char)(n); \
Michael J. Spencer 1:f5ac63519541 86 } \
Michael J. Spencer 1:f5ac63519541 87 }
Michael J. Spencer 1:f5ac63519541 88 #define ENCODEZ(n) { \
Michael J. Spencer 1:f5ac63519541 89 if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \
Michael J. Spencer 1:f5ac63519541 90 *cp++ = 0; \
Michael J. Spencer 1:f5ac63519541 91 cp[1] = (u_char)(n); \
Michael J. Spencer 1:f5ac63519541 92 cp[0] = (u_char)((n) >> 8); \
Michael J. Spencer 1:f5ac63519541 93 cp += 2; \
Michael J. Spencer 1:f5ac63519541 94 } else { \
Michael J. Spencer 1:f5ac63519541 95 *cp++ = (u_char)(n); \
Michael J. Spencer 1:f5ac63519541 96 } \
Michael J. Spencer 1:f5ac63519541 97 }
Michael J. Spencer 1:f5ac63519541 98
Michael J. Spencer 1:f5ac63519541 99 #define DECODEL(f) { \
Michael J. Spencer 1:f5ac63519541 100 if (*cp == 0) {\
Michael J. Spencer 1:f5ac63519541 101 u32_t tmp = ntohl(f) + ((cp[1] << 8) | cp[2]); \
Michael J. Spencer 1:f5ac63519541 102 (f) = htonl(tmp); \
Michael J. Spencer 1:f5ac63519541 103 cp += 3; \
Michael J. Spencer 1:f5ac63519541 104 } else { \
Michael J. Spencer 1:f5ac63519541 105 u32_t tmp = ntohl(f) + (u32_t)*cp++; \
Michael J. Spencer 1:f5ac63519541 106 (f) = htonl(tmp); \
Michael J. Spencer 1:f5ac63519541 107 } \
Michael J. Spencer 1:f5ac63519541 108 }
Michael J. Spencer 1:f5ac63519541 109
Michael J. Spencer 1:f5ac63519541 110 #define DECODES(f) { \
Michael J. Spencer 1:f5ac63519541 111 if (*cp == 0) {\
Michael J. Spencer 1:f5ac63519541 112 u_short tmp = ntohs(f) + (((u_short)cp[1] << 8) | cp[2]); \
Michael J. Spencer 1:f5ac63519541 113 (f) = htons(tmp); \
Michael J. Spencer 1:f5ac63519541 114 cp += 3; \
Michael J. Spencer 1:f5ac63519541 115 } else { \
Michael J. Spencer 1:f5ac63519541 116 u_short tmp = ntohs(f) + (u_short)*cp++; \
Michael J. Spencer 1:f5ac63519541 117 (f) = htons(tmp); \
Michael J. Spencer 1:f5ac63519541 118 } \
Michael J. Spencer 1:f5ac63519541 119 }
Michael J. Spencer 1:f5ac63519541 120
Michael J. Spencer 1:f5ac63519541 121 #define DECODEU(f) { \
Michael J. Spencer 1:f5ac63519541 122 if (*cp == 0) {\
Michael J. Spencer 1:f5ac63519541 123 (f) = htons(((u_short)cp[1] << 8) | cp[2]); \
Michael J. Spencer 1:f5ac63519541 124 cp += 3; \
Michael J. Spencer 1:f5ac63519541 125 } else { \
Michael J. Spencer 1:f5ac63519541 126 (f) = htons((u_short)*cp++); \
Michael J. Spencer 1:f5ac63519541 127 } \
Michael J. Spencer 1:f5ac63519541 128 }
Michael J. Spencer 1:f5ac63519541 129
Michael J. Spencer 1:f5ac63519541 130 /*
Michael J. Spencer 1:f5ac63519541 131 * vj_compress_tcp - Attempt to do Van Jacobson header compression on a
Michael J. Spencer 1:f5ac63519541 132 * packet. This assumes that nb and comp are not null and that the first
Michael J. Spencer 1:f5ac63519541 133 * buffer of the chain contains a valid IP header.
Michael J. Spencer 1:f5ac63519541 134 * Return the VJ type code indicating whether or not the packet was
Michael J. Spencer 1:f5ac63519541 135 * compressed.
Michael J. Spencer 1:f5ac63519541 136 */
Michael J. Spencer 1:f5ac63519541 137 u_int
Michael J. Spencer 1:f5ac63519541 138 vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
Michael J. Spencer 1:f5ac63519541 139 {
Michael J. Spencer 1:f5ac63519541 140 register struct ip_hdr *ip = (struct ip_hdr *)pb->payload;
Michael J. Spencer 1:f5ac63519541 141 register struct cstate *cs = comp->last_cs->cs_next;
Michael J. Spencer 1:f5ac63519541 142 register u_short hlen = IPH_HL(ip);
Michael J. Spencer 1:f5ac63519541 143 register struct tcp_hdr *oth;
Michael J. Spencer 1:f5ac63519541 144 register struct tcp_hdr *th;
Michael J. Spencer 1:f5ac63519541 145 register u_short deltaS, deltaA;
Michael J. Spencer 1:f5ac63519541 146 register u_long deltaL;
Michael J. Spencer 1:f5ac63519541 147 register u_int changes = 0;
Michael J. Spencer 1:f5ac63519541 148 u_char new_seq[16];
Michael J. Spencer 1:f5ac63519541 149 register u_char *cp = new_seq;
Michael J. Spencer 1:f5ac63519541 150
Michael J. Spencer 1:f5ac63519541 151 /*
Michael J. Spencer 1:f5ac63519541 152 * Check that the packet is IP proto TCP.
Michael J. Spencer 1:f5ac63519541 153 */
Michael J. Spencer 1:f5ac63519541 154 if (IPH_PROTO(ip) != IP_PROTO_TCP) {
Michael J. Spencer 1:f5ac63519541 155 return (TYPE_IP);
Michael J. Spencer 1:f5ac63519541 156 }
Michael J. Spencer 1:f5ac63519541 157
Michael J. Spencer 1:f5ac63519541 158 /*
Michael J. Spencer 1:f5ac63519541 159 * Bail if this is an IP fragment or if the TCP packet isn't
Michael J. Spencer 1:f5ac63519541 160 * `compressible' (i.e., ACK isn't set or some other control bit is
Michael J. Spencer 1:f5ac63519541 161 * set).
Michael J. Spencer 1:f5ac63519541 162 */
Michael J. Spencer 1:f5ac63519541 163 if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || pb->tot_len < 40) {
Michael J. Spencer 1:f5ac63519541 164 return (TYPE_IP);
Michael J. Spencer 1:f5ac63519541 165 }
Michael J. Spencer 1:f5ac63519541 166 th = (struct tcp_hdr *)&((long *)ip)[hlen];
Michael J. Spencer 1:f5ac63519541 167 if ((TCPH_FLAGS(th) & (TCP_SYN|TCP_FIN|TCP_RST|TCP_ACK)) != TCP_ACK) {
Michael J. Spencer 1:f5ac63519541 168 return (TYPE_IP);
Michael J. Spencer 1:f5ac63519541 169 }
Michael J. Spencer 1:f5ac63519541 170 /*
Michael J. Spencer 1:f5ac63519541 171 * Packet is compressible -- we're going to send either a
Michael J. Spencer 1:f5ac63519541 172 * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
Michael J. Spencer 1:f5ac63519541 173 * to locate (or create) the connection state. Special case the
Michael J. Spencer 1:f5ac63519541 174 * most recently used connection since it's most likely to be used
Michael J. Spencer 1:f5ac63519541 175 * again & we don't have to do any reordering if it's used.
Michael J. Spencer 1:f5ac63519541 176 */
Michael J. Spencer 1:f5ac63519541 177 INCR(vjs_packets);
Michael J. Spencer 1:f5ac63519541 178 if (!ip_addr_cmp(&ip->src, &cs->cs_ip.src)
Michael J. Spencer 1:f5ac63519541 179 || !ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
Michael J. Spencer 1:f5ac63519541 180 || *(long *)th != ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
Michael J. Spencer 1:f5ac63519541 181 /*
Michael J. Spencer 1:f5ac63519541 182 * Wasn't the first -- search for it.
Michael J. Spencer 1:f5ac63519541 183 *
Michael J. Spencer 1:f5ac63519541 184 * States are kept in a circularly linked list with
Michael J. Spencer 1:f5ac63519541 185 * last_cs pointing to the end of the list. The
Michael J. Spencer 1:f5ac63519541 186 * list is kept in lru order by moving a state to the
Michael J. Spencer 1:f5ac63519541 187 * head of the list whenever it is referenced. Since
Michael J. Spencer 1:f5ac63519541 188 * the list is short and, empirically, the connection
Michael J. Spencer 1:f5ac63519541 189 * we want is almost always near the front, we locate
Michael J. Spencer 1:f5ac63519541 190 * states via linear search. If we don't find a state
Michael J. Spencer 1:f5ac63519541 191 * for the datagram, the oldest state is (re-)used.
Michael J. Spencer 1:f5ac63519541 192 */
Michael J. Spencer 1:f5ac63519541 193 register struct cstate *lcs;
Michael J. Spencer 1:f5ac63519541 194 register struct cstate *lastcs = comp->last_cs;
Michael J. Spencer 1:f5ac63519541 195
Michael J. Spencer 1:f5ac63519541 196 do {
Michael J. Spencer 1:f5ac63519541 197 lcs = cs; cs = cs->cs_next;
Michael J. Spencer 1:f5ac63519541 198 INCR(vjs_searches);
Michael J. Spencer 1:f5ac63519541 199 if (ip_addr_cmp(&ip->src, &cs->cs_ip.src)
Michael J. Spencer 1:f5ac63519541 200 && ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
Michael J. Spencer 1:f5ac63519541 201 && *(long *)th == ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
Michael J. Spencer 1:f5ac63519541 202 goto found;
Michael J. Spencer 1:f5ac63519541 203 }
Michael J. Spencer 1:f5ac63519541 204 } while (cs != lastcs);
Michael J. Spencer 1:f5ac63519541 205
Michael J. Spencer 1:f5ac63519541 206 /*
Michael J. Spencer 1:f5ac63519541 207 * Didn't find it -- re-use oldest cstate. Send an
Michael J. Spencer 1:f5ac63519541 208 * uncompressed packet that tells the other side what
Michael J. Spencer 1:f5ac63519541 209 * connection number we're using for this conversation.
Michael J. Spencer 1:f5ac63519541 210 * Note that since the state list is circular, the oldest
Michael J. Spencer 1:f5ac63519541 211 * state points to the newest and we only need to set
Michael J. Spencer 1:f5ac63519541 212 * last_cs to update the lru linkage.
Michael J. Spencer 1:f5ac63519541 213 */
Michael J. Spencer 1:f5ac63519541 214 INCR(vjs_misses);
Michael J. Spencer 1:f5ac63519541 215 comp->last_cs = lcs;
Michael J. Spencer 1:f5ac63519541 216 hlen += TCPH_OFFSET(th);
Michael J. Spencer 1:f5ac63519541 217 hlen <<= 2;
Michael J. Spencer 1:f5ac63519541 218 /* Check that the IP/TCP headers are contained in the first buffer. */
Michael J. Spencer 1:f5ac63519541 219 if (hlen > pb->len) {
Michael J. Spencer 1:f5ac63519541 220 return (TYPE_IP);
Michael J. Spencer 1:f5ac63519541 221 }
Michael J. Spencer 1:f5ac63519541 222 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 223
Michael J. Spencer 1:f5ac63519541 224 found:
Michael J. Spencer 1:f5ac63519541 225 /*
Michael J. Spencer 1:f5ac63519541 226 * Found it -- move to the front on the connection list.
Michael J. Spencer 1:f5ac63519541 227 */
Michael J. Spencer 1:f5ac63519541 228 if (cs == lastcs) {
Michael J. Spencer 1:f5ac63519541 229 comp->last_cs = lcs;
Michael J. Spencer 1:f5ac63519541 230 } else {
Michael J. Spencer 1:f5ac63519541 231 lcs->cs_next = cs->cs_next;
Michael J. Spencer 1:f5ac63519541 232 cs->cs_next = lastcs->cs_next;
Michael J. Spencer 1:f5ac63519541 233 lastcs->cs_next = cs;
Michael J. Spencer 1:f5ac63519541 234 }
Michael J. Spencer 1:f5ac63519541 235 }
Michael J. Spencer 1:f5ac63519541 236
Michael J. Spencer 1:f5ac63519541 237 oth = (struct tcp_hdr *)&((long *)&cs->cs_ip)[hlen];
Michael J. Spencer 1:f5ac63519541 238 deltaS = hlen;
Michael J. Spencer 1:f5ac63519541 239 hlen += TCPH_OFFSET(th);
Michael J. Spencer 1:f5ac63519541 240 hlen <<= 2;
Michael J. Spencer 1:f5ac63519541 241 /* Check that the IP/TCP headers are contained in the first buffer. */
Michael J. Spencer 1:f5ac63519541 242 if (hlen > pb->len) {
Michael J. Spencer 1:f5ac63519541 243 PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
Michael J. Spencer 1:f5ac63519541 244 return (TYPE_IP);
Michael J. Spencer 1:f5ac63519541 245 }
Michael J. Spencer 1:f5ac63519541 246
Michael J. Spencer 1:f5ac63519541 247 /*
Michael J. Spencer 1:f5ac63519541 248 * Make sure that only what we expect to change changed. The first
Michael J. Spencer 1:f5ac63519541 249 * line of the `if' checks the IP protocol version, header length &
Michael J. Spencer 1:f5ac63519541 250 * type of service. The 2nd line checks the "Don't fragment" bit.
Michael J. Spencer 1:f5ac63519541 251 * The 3rd line checks the time-to-live and protocol (the protocol
Michael J. Spencer 1:f5ac63519541 252 * check is unnecessary but costless). The 4th line checks the TCP
Michael J. Spencer 1:f5ac63519541 253 * header length. The 5th line checks IP options, if any. The 6th
Michael J. Spencer 1:f5ac63519541 254 * line checks TCP options, if any. If any of these things are
Michael J. Spencer 1:f5ac63519541 255 * different between the previous & current datagram, we send the
Michael J. Spencer 1:f5ac63519541 256 * current datagram `uncompressed'.
Michael J. Spencer 1:f5ac63519541 257 */
Michael J. Spencer 1:f5ac63519541 258 if (((u_short *)ip)[0] != ((u_short *)&cs->cs_ip)[0]
Michael J. Spencer 1:f5ac63519541 259 || ((u_short *)ip)[3] != ((u_short *)&cs->cs_ip)[3]
Michael J. Spencer 1:f5ac63519541 260 || ((u_short *)ip)[4] != ((u_short *)&cs->cs_ip)[4]
Michael J. Spencer 1:f5ac63519541 261 || TCPH_OFFSET(th) != TCPH_OFFSET(oth)
Michael J. Spencer 1:f5ac63519541 262 || (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2))
Michael J. Spencer 1:f5ac63519541 263 || (TCPH_OFFSET(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_OFFSET(th) - 5) << 2))) {
Michael J. Spencer 1:f5ac63519541 264 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 265 }
Michael J. Spencer 1:f5ac63519541 266
Michael J. Spencer 1:f5ac63519541 267 /*
Michael J. Spencer 1:f5ac63519541 268 * Figure out which of the changing fields changed. The
Michael J. Spencer 1:f5ac63519541 269 * receiver expects changes in the order: urgent, window,
Michael J. Spencer 1:f5ac63519541 270 * ack, seq (the order minimizes the number of temporaries
Michael J. Spencer 1:f5ac63519541 271 * needed in this section of code).
Michael J. Spencer 1:f5ac63519541 272 */
Michael J. Spencer 1:f5ac63519541 273 if (TCPH_FLAGS(th) & TCP_URG) {
Michael J. Spencer 1:f5ac63519541 274 deltaS = ntohs(th->urgp);
Michael J. Spencer 1:f5ac63519541 275 ENCODEZ(deltaS);
Michael J. Spencer 1:f5ac63519541 276 changes |= NEW_U;
Michael J. Spencer 1:f5ac63519541 277 } else if (th->urgp != oth->urgp) {
Michael J. Spencer 1:f5ac63519541 278 /* argh! URG not set but urp changed -- a sensible
Michael J. Spencer 1:f5ac63519541 279 * implementation should never do this but RFC793
Michael J. Spencer 1:f5ac63519541 280 * doesn't prohibit the change so we have to deal
Michael J. Spencer 1:f5ac63519541 281 * with it. */
Michael J. Spencer 1:f5ac63519541 282 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 283 }
Michael J. Spencer 1:f5ac63519541 284
Michael J. Spencer 1:f5ac63519541 285 if ((deltaS = (u_short)(ntohs(th->wnd) - ntohs(oth->wnd))) != 0) {
Michael J. Spencer 1:f5ac63519541 286 ENCODE(deltaS);
Michael J. Spencer 1:f5ac63519541 287 changes |= NEW_W;
Michael J. Spencer 1:f5ac63519541 288 }
Michael J. Spencer 1:f5ac63519541 289
Michael J. Spencer 1:f5ac63519541 290 if ((deltaL = ntohl(th->ackno) - ntohl(oth->ackno)) != 0) {
Michael J. Spencer 1:f5ac63519541 291 if (deltaL > 0xffff) {
Michael J. Spencer 1:f5ac63519541 292 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 293 }
Michael J. Spencer 1:f5ac63519541 294 deltaA = (u_short)deltaL;
Michael J. Spencer 1:f5ac63519541 295 ENCODE(deltaA);
Michael J. Spencer 1:f5ac63519541 296 changes |= NEW_A;
Michael J. Spencer 1:f5ac63519541 297 }
Michael J. Spencer 1:f5ac63519541 298
Michael J. Spencer 1:f5ac63519541 299 if ((deltaL = ntohl(th->seqno) - ntohl(oth->seqno)) != 0) {
Michael J. Spencer 1:f5ac63519541 300 if (deltaL > 0xffff) {
Michael J. Spencer 1:f5ac63519541 301 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 302 }
Michael J. Spencer 1:f5ac63519541 303 deltaS = (u_short)deltaL;
Michael J. Spencer 1:f5ac63519541 304 ENCODE(deltaS);
Michael J. Spencer 1:f5ac63519541 305 changes |= NEW_S;
Michael J. Spencer 1:f5ac63519541 306 }
Michael J. Spencer 1:f5ac63519541 307
Michael J. Spencer 1:f5ac63519541 308 switch(changes) {
Michael J. Spencer 1:f5ac63519541 309 case 0:
Michael J. Spencer 1:f5ac63519541 310 /*
Michael J. Spencer 1:f5ac63519541 311 * Nothing changed. If this packet contains data and the
Michael J. Spencer 1:f5ac63519541 312 * last one didn't, this is probably a data packet following
Michael J. Spencer 1:f5ac63519541 313 * an ack (normal on an interactive connection) and we send
Michael J. Spencer 1:f5ac63519541 314 * it compressed. Otherwise it's probably a retransmit,
Michael J. Spencer 1:f5ac63519541 315 * retransmitted ack or window probe. Send it uncompressed
Michael J. Spencer 1:f5ac63519541 316 * in case the other side missed the compressed version.
Michael J. Spencer 1:f5ac63519541 317 */
Michael J. Spencer 1:f5ac63519541 318 if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) &&
Michael J. Spencer 1:f5ac63519541 319 ntohs(IPH_LEN(&cs->cs_ip)) == hlen) {
Michael J. Spencer 1:f5ac63519541 320 break;
Michael J. Spencer 1:f5ac63519541 321 }
Michael J. Spencer 1:f5ac63519541 322
Michael J. Spencer 1:f5ac63519541 323 /* (fall through) */
Michael J. Spencer 1:f5ac63519541 324
Michael J. Spencer 1:f5ac63519541 325 case SPECIAL_I:
Michael J. Spencer 1:f5ac63519541 326 case SPECIAL_D:
Michael J. Spencer 1:f5ac63519541 327 /*
Michael J. Spencer 1:f5ac63519541 328 * actual changes match one of our special case encodings --
Michael J. Spencer 1:f5ac63519541 329 * send packet uncompressed.
Michael J. Spencer 1:f5ac63519541 330 */
Michael J. Spencer 1:f5ac63519541 331 goto uncompressed;
Michael J. Spencer 1:f5ac63519541 332
Michael J. Spencer 1:f5ac63519541 333 case NEW_S|NEW_A:
Michael J. Spencer 1:f5ac63519541 334 if (deltaS == deltaA && deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
Michael J. Spencer 1:f5ac63519541 335 /* special case for echoed terminal traffic */
Michael J. Spencer 1:f5ac63519541 336 changes = SPECIAL_I;
Michael J. Spencer 1:f5ac63519541 337 cp = new_seq;
Michael J. Spencer 1:f5ac63519541 338 }
Michael J. Spencer 1:f5ac63519541 339 break;
Michael J. Spencer 1:f5ac63519541 340
Michael J. Spencer 1:f5ac63519541 341 case NEW_S:
Michael J. Spencer 1:f5ac63519541 342 if (deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
Michael J. Spencer 1:f5ac63519541 343 /* special case for data xfer */
Michael J. Spencer 1:f5ac63519541 344 changes = SPECIAL_D;
Michael J. Spencer 1:f5ac63519541 345 cp = new_seq;
Michael J. Spencer 1:f5ac63519541 346 }
Michael J. Spencer 1:f5ac63519541 347 break;
Michael J. Spencer 1:f5ac63519541 348 }
Michael J. Spencer 1:f5ac63519541 349
Michael J. Spencer 1:f5ac63519541 350 deltaS = (u_short)(ntohs(IPH_ID(ip)) - ntohs(IPH_ID(&cs->cs_ip)));
Michael J. Spencer 1:f5ac63519541 351 if (deltaS != 1) {
Michael J. Spencer 1:f5ac63519541 352 ENCODEZ(deltaS);
Michael J. Spencer 1:f5ac63519541 353 changes |= NEW_I;
Michael J. Spencer 1:f5ac63519541 354 }
Michael J. Spencer 1:f5ac63519541 355 if (TCPH_FLAGS(th) & TCP_PSH) {
Michael J. Spencer 1:f5ac63519541 356 changes |= TCP_PUSH_BIT;
Michael J. Spencer 1:f5ac63519541 357 }
Michael J. Spencer 1:f5ac63519541 358 /*
Michael J. Spencer 1:f5ac63519541 359 * Grab the cksum before we overwrite it below. Then update our
Michael J. Spencer 1:f5ac63519541 360 * state with this packet's header.
Michael J. Spencer 1:f5ac63519541 361 */
Michael J. Spencer 1:f5ac63519541 362 deltaA = ntohs(th->chksum);
Michael J. Spencer 1:f5ac63519541 363 BCOPY(ip, &cs->cs_ip, hlen);
Michael J. Spencer 1:f5ac63519541 364
Michael J. Spencer 1:f5ac63519541 365 /*
Michael J. Spencer 1:f5ac63519541 366 * We want to use the original packet as our compressed packet.
Michael J. Spencer 1:f5ac63519541 367 * (cp - new_seq) is the number of bytes we need for compressed
Michael J. Spencer 1:f5ac63519541 368 * sequence numbers. In addition we need one byte for the change
Michael J. Spencer 1:f5ac63519541 369 * mask, one for the connection id and two for the tcp checksum.
Michael J. Spencer 1:f5ac63519541 370 * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how
Michael J. Spencer 1:f5ac63519541 371 * many bytes of the original packet to toss so subtract the two to
Michael J. Spencer 1:f5ac63519541 372 * get the new packet size.
Michael J. Spencer 1:f5ac63519541 373 */
Michael J. Spencer 1:f5ac63519541 374 deltaS = (u_short)(cp - new_seq);
Michael J. Spencer 1:f5ac63519541 375 if (!comp->compressSlot || comp->last_xmit != cs->cs_id) {
Michael J. Spencer 1:f5ac63519541 376 comp->last_xmit = cs->cs_id;
Michael J. Spencer 1:f5ac63519541 377 hlen -= deltaS + 4;
Michael J. Spencer 1:f5ac63519541 378 if(pbuf_header(pb, -hlen)){
Michael J. Spencer 1:f5ac63519541 379 /* Can we cope with this failing? Just assert for now */
Michael J. Spencer 1:f5ac63519541 380 LWIP_ASSERT("pbuf_header failed\n", 0);
Michael J. Spencer 1:f5ac63519541 381 }
Michael J. Spencer 1:f5ac63519541 382 cp = (u_char *)pb->payload;
Michael J. Spencer 1:f5ac63519541 383 *cp++ = (u_char)(changes | NEW_C);
Michael J. Spencer 1:f5ac63519541 384 *cp++ = cs->cs_id;
Michael J. Spencer 1:f5ac63519541 385 } else {
Michael J. Spencer 1:f5ac63519541 386 hlen -= deltaS + 3;
Michael J. Spencer 1:f5ac63519541 387 if(pbuf_header(pb, -hlen)) {
Michael J. Spencer 1:f5ac63519541 388 /* Can we cope with this failing? Just assert for now */
Michael J. Spencer 1:f5ac63519541 389 LWIP_ASSERT("pbuf_header failed\n", 0);
Michael J. Spencer 1:f5ac63519541 390 }
Michael J. Spencer 1:f5ac63519541 391 cp = (u_char *)pb->payload;
Michael J. Spencer 1:f5ac63519541 392 *cp++ = (u_char)changes;
Michael J. Spencer 1:f5ac63519541 393 }
Michael J. Spencer 1:f5ac63519541 394 *cp++ = (u_char)(deltaA >> 8);
Michael J. Spencer 1:f5ac63519541 395 *cp++ = (u_char)deltaA;
Michael J. Spencer 1:f5ac63519541 396 BCOPY(new_seq, cp, deltaS);
Michael J. Spencer 1:f5ac63519541 397 INCR(vjs_compressed);
Michael J. Spencer 1:f5ac63519541 398 return (TYPE_COMPRESSED_TCP);
Michael J. Spencer 1:f5ac63519541 399
Michael J. Spencer 1:f5ac63519541 400 /*
Michael J. Spencer 1:f5ac63519541 401 * Update connection state cs & send uncompressed packet (that is,
Michael J. Spencer 1:f5ac63519541 402 * a regular ip/tcp packet but with the 'conversation id' we hope
Michael J. Spencer 1:f5ac63519541 403 * to use on future compressed packets in the protocol field).
Michael J. Spencer 1:f5ac63519541 404 */
Michael J. Spencer 1:f5ac63519541 405 uncompressed:
Michael J. Spencer 1:f5ac63519541 406 BCOPY(ip, &cs->cs_ip, hlen);
Michael J. Spencer 1:f5ac63519541 407 IPH_PROTO_SET(ip, cs->cs_id);
Michael J. Spencer 1:f5ac63519541 408 comp->last_xmit = cs->cs_id;
Michael J. Spencer 1:f5ac63519541 409 return (TYPE_UNCOMPRESSED_TCP);
Michael J. Spencer 1:f5ac63519541 410 }
Michael J. Spencer 1:f5ac63519541 411
Michael J. Spencer 1:f5ac63519541 412 /*
Michael J. Spencer 1:f5ac63519541 413 * Called when we may have missed a packet.
Michael J. Spencer 1:f5ac63519541 414 */
Michael J. Spencer 1:f5ac63519541 415 void
Michael J. Spencer 1:f5ac63519541 416 vj_uncompress_err(struct vjcompress *comp)
Michael J. Spencer 1:f5ac63519541 417 {
Michael J. Spencer 1:f5ac63519541 418 comp->flags |= VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 419 INCR(vjs_errorin);
Michael J. Spencer 1:f5ac63519541 420 }
Michael J. Spencer 1:f5ac63519541 421
Michael J. Spencer 1:f5ac63519541 422 /*
Michael J. Spencer 1:f5ac63519541 423 * "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP.
Michael J. Spencer 1:f5ac63519541 424 * Return 0 on success, -1 on failure.
Michael J. Spencer 1:f5ac63519541 425 */
Michael J. Spencer 1:f5ac63519541 426 int
Michael J. Spencer 1:f5ac63519541 427 vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp)
Michael J. Spencer 1:f5ac63519541 428 {
Michael J. Spencer 1:f5ac63519541 429 register u_int hlen;
Michael J. Spencer 1:f5ac63519541 430 register struct cstate *cs;
Michael J. Spencer 1:f5ac63519541 431 register struct ip_hdr *ip;
Michael J. Spencer 1:f5ac63519541 432
Michael J. Spencer 1:f5ac63519541 433 ip = (struct ip_hdr *)nb->payload;
Michael J. Spencer 1:f5ac63519541 434 hlen = IPH_HL(ip) << 2;
Michael J. Spencer 1:f5ac63519541 435 if (IPH_PROTO(ip) >= MAX_SLOTS
Michael J. Spencer 1:f5ac63519541 436 || hlen + sizeof(struct tcp_hdr) > nb->len
Michael J. Spencer 1:f5ac63519541 437 || (hlen += TCPH_OFFSET(((struct tcp_hdr *)&((char *)ip)[hlen])) << 2)
Michael J. Spencer 1:f5ac63519541 438 > nb->len
Michael J. Spencer 1:f5ac63519541 439 || hlen > MAX_HDR) {
Michael J. Spencer 1:f5ac63519541 440 PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n",
Michael J. Spencer 1:f5ac63519541 441 IPH_PROTO(ip), hlen, nb->len));
Michael J. Spencer 1:f5ac63519541 442 comp->flags |= VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 443 INCR(vjs_errorin);
Michael J. Spencer 1:f5ac63519541 444 return -1;
Michael J. Spencer 1:f5ac63519541 445 }
Michael J. Spencer 1:f5ac63519541 446 cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)];
Michael J. Spencer 1:f5ac63519541 447 comp->flags &=~ VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 448 IPH_PROTO_SET(ip, IP_PROTO_TCP);
Michael J. Spencer 1:f5ac63519541 449 BCOPY(ip, &cs->cs_ip, hlen);
Michael J. Spencer 1:f5ac63519541 450 cs->cs_hlen = (u_short)hlen;
Michael J. Spencer 1:f5ac63519541 451 INCR(vjs_uncompressedin);
Michael J. Spencer 1:f5ac63519541 452 return 0;
Michael J. Spencer 1:f5ac63519541 453 }
Michael J. Spencer 1:f5ac63519541 454
Michael J. Spencer 1:f5ac63519541 455 /*
Michael J. Spencer 1:f5ac63519541 456 * Uncompress a packet of type TYPE_COMPRESSED_TCP.
Michael J. Spencer 1:f5ac63519541 457 * The packet is composed of a buffer chain and the first buffer
Michael J. Spencer 1:f5ac63519541 458 * must contain an accurate chain length.
Michael J. Spencer 1:f5ac63519541 459 * The first buffer must include the entire compressed TCP/IP header.
Michael J. Spencer 1:f5ac63519541 460 * This procedure replaces the compressed header with the uncompressed
Michael J. Spencer 1:f5ac63519541 461 * header and returns the length of the VJ header.
Michael J. Spencer 1:f5ac63519541 462 */
Michael J. Spencer 1:f5ac63519541 463 int
Michael J. Spencer 1:f5ac63519541 464 vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp)
Michael J. Spencer 1:f5ac63519541 465 {
Michael J. Spencer 1:f5ac63519541 466 u_char *cp;
Michael J. Spencer 1:f5ac63519541 467 struct tcp_hdr *th;
Michael J. Spencer 1:f5ac63519541 468 struct cstate *cs;
Michael J. Spencer 1:f5ac63519541 469 u_short *bp;
Michael J. Spencer 1:f5ac63519541 470 struct pbuf *n0 = *nb;
Michael J. Spencer 1:f5ac63519541 471 u32_t tmp;
Michael J. Spencer 1:f5ac63519541 472 u_int vjlen, hlen, changes;
Michael J. Spencer 1:f5ac63519541 473
Michael J. Spencer 1:f5ac63519541 474 INCR(vjs_compressedin);
Michael J. Spencer 1:f5ac63519541 475 cp = (u_char *)n0->payload;
Michael J. Spencer 1:f5ac63519541 476 changes = *cp++;
Michael J. Spencer 1:f5ac63519541 477 if (changes & NEW_C) {
Michael J. Spencer 1:f5ac63519541 478 /*
Michael J. Spencer 1:f5ac63519541 479 * Make sure the state index is in range, then grab the state.
Michael J. Spencer 1:f5ac63519541 480 * If we have a good state index, clear the 'discard' flag.
Michael J. Spencer 1:f5ac63519541 481 */
Michael J. Spencer 1:f5ac63519541 482 if (*cp >= MAX_SLOTS) {
Michael J. Spencer 1:f5ac63519541 483 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp));
Michael J. Spencer 1:f5ac63519541 484 goto bad;
Michael J. Spencer 1:f5ac63519541 485 }
Michael J. Spencer 1:f5ac63519541 486
Michael J. Spencer 1:f5ac63519541 487 comp->flags &=~ VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 488 comp->last_recv = *cp++;
Michael J. Spencer 1:f5ac63519541 489 } else {
Michael J. Spencer 1:f5ac63519541 490 /*
Michael J. Spencer 1:f5ac63519541 491 * this packet has an implicit state index. If we've
Michael J. Spencer 1:f5ac63519541 492 * had a line error since the last time we got an
Michael J. Spencer 1:f5ac63519541 493 * explicit state index, we have to toss the packet.
Michael J. Spencer 1:f5ac63519541 494 */
Michael J. Spencer 1:f5ac63519541 495 if (comp->flags & VJF_TOSS) {
Michael J. Spencer 1:f5ac63519541 496 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n"));
Michael J. Spencer 1:f5ac63519541 497 INCR(vjs_tossed);
Michael J. Spencer 1:f5ac63519541 498 return (-1);
Michael J. Spencer 1:f5ac63519541 499 }
Michael J. Spencer 1:f5ac63519541 500 }
Michael J. Spencer 1:f5ac63519541 501 cs = &comp->rstate[comp->last_recv];
Michael J. Spencer 1:f5ac63519541 502 hlen = IPH_HL(&cs->cs_ip) << 2;
Michael J. Spencer 1:f5ac63519541 503 th = (struct tcp_hdr *)&((u_char *)&cs->cs_ip)[hlen];
Michael J. Spencer 1:f5ac63519541 504 th->chksum = htons((*cp << 8) | cp[1]);
Michael J. Spencer 1:f5ac63519541 505 cp += 2;
Michael J. Spencer 1:f5ac63519541 506 if (changes & TCP_PUSH_BIT) {
Michael J. Spencer 1:f5ac63519541 507 TCPH_SET_FLAG(th, TCP_PSH);
Michael J. Spencer 1:f5ac63519541 508 } else {
Michael J. Spencer 1:f5ac63519541 509 TCPH_UNSET_FLAG(th, TCP_PSH);
Michael J. Spencer 1:f5ac63519541 510 }
Michael J. Spencer 1:f5ac63519541 511
Michael J. Spencer 1:f5ac63519541 512 switch (changes & SPECIALS_MASK) {
Michael J. Spencer 1:f5ac63519541 513 case SPECIAL_I:
Michael J. Spencer 1:f5ac63519541 514 {
Michael J. Spencer 1:f5ac63519541 515 register u32_t i = ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
Michael J. Spencer 1:f5ac63519541 516 /* some compilers can't nest inline assembler.. */
Michael J. Spencer 1:f5ac63519541 517 tmp = ntohl(th->ackno) + i;
Michael J. Spencer 1:f5ac63519541 518 th->ackno = htonl(tmp);
Michael J. Spencer 1:f5ac63519541 519 tmp = ntohl(th->seqno) + i;
Michael J. Spencer 1:f5ac63519541 520 th->seqno = htonl(tmp);
Michael J. Spencer 1:f5ac63519541 521 }
Michael J. Spencer 1:f5ac63519541 522 break;
Michael J. Spencer 1:f5ac63519541 523
Michael J. Spencer 1:f5ac63519541 524 case SPECIAL_D:
Michael J. Spencer 1:f5ac63519541 525 /* some compilers can't nest inline assembler.. */
Michael J. Spencer 1:f5ac63519541 526 tmp = ntohl(th->seqno) + ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
Michael J. Spencer 1:f5ac63519541 527 th->seqno = htonl(tmp);
Michael J. Spencer 1:f5ac63519541 528 break;
Michael J. Spencer 1:f5ac63519541 529
Michael J. Spencer 1:f5ac63519541 530 default:
Michael J. Spencer 1:f5ac63519541 531 if (changes & NEW_U) {
Michael J. Spencer 1:f5ac63519541 532 TCPH_SET_FLAG(th, TCP_URG);
Michael J. Spencer 1:f5ac63519541 533 DECODEU(th->urgp);
Michael J. Spencer 1:f5ac63519541 534 } else {
Michael J. Spencer 1:f5ac63519541 535 TCPH_UNSET_FLAG(th, TCP_URG);
Michael J. Spencer 1:f5ac63519541 536 }
Michael J. Spencer 1:f5ac63519541 537 if (changes & NEW_W) {
Michael J. Spencer 1:f5ac63519541 538 DECODES(th->wnd);
Michael J. Spencer 1:f5ac63519541 539 }
Michael J. Spencer 1:f5ac63519541 540 if (changes & NEW_A) {
Michael J. Spencer 1:f5ac63519541 541 DECODEL(th->ackno);
Michael J. Spencer 1:f5ac63519541 542 }
Michael J. Spencer 1:f5ac63519541 543 if (changes & NEW_S) {
Michael J. Spencer 1:f5ac63519541 544 DECODEL(th->seqno);
Michael J. Spencer 1:f5ac63519541 545 }
Michael J. Spencer 1:f5ac63519541 546 break;
Michael J. Spencer 1:f5ac63519541 547 }
Michael J. Spencer 1:f5ac63519541 548 if (changes & NEW_I) {
Michael J. Spencer 1:f5ac63519541 549 DECODES(cs->cs_ip._id);
Michael J. Spencer 1:f5ac63519541 550 } else {
Michael J. Spencer 1:f5ac63519541 551 IPH_ID_SET(&cs->cs_ip, ntohs(IPH_ID(&cs->cs_ip)) + 1);
Michael J. Spencer 1:f5ac63519541 552 IPH_ID_SET(&cs->cs_ip, htons(IPH_ID(&cs->cs_ip)));
Michael J. Spencer 1:f5ac63519541 553 }
Michael J. Spencer 1:f5ac63519541 554
Michael J. Spencer 1:f5ac63519541 555 /*
Michael J. Spencer 1:f5ac63519541 556 * At this point, cp points to the first byte of data in the
Michael J. Spencer 1:f5ac63519541 557 * packet. Fill in the IP total length and update the IP
Michael J. Spencer 1:f5ac63519541 558 * header checksum.
Michael J. Spencer 1:f5ac63519541 559 */
Michael J. Spencer 1:f5ac63519541 560 vjlen = (u_short)(cp - (u_char*)n0->payload);
Michael J. Spencer 1:f5ac63519541 561 if (n0->len < vjlen) {
Michael J. Spencer 1:f5ac63519541 562 /*
Michael J. Spencer 1:f5ac63519541 563 * We must have dropped some characters (crc should detect
Michael J. Spencer 1:f5ac63519541 564 * this but the old slip framing won't)
Michael J. Spencer 1:f5ac63519541 565 */
Michael J. Spencer 1:f5ac63519541 566 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n",
Michael J. Spencer 1:f5ac63519541 567 n0->len, vjlen));
Michael J. Spencer 1:f5ac63519541 568 goto bad;
Michael J. Spencer 1:f5ac63519541 569 }
Michael J. Spencer 1:f5ac63519541 570
Michael J. Spencer 1:f5ac63519541 571 #if BYTE_ORDER == LITTLE_ENDIAN
Michael J. Spencer 1:f5ac63519541 572 tmp = n0->tot_len - vjlen + cs->cs_hlen;
Michael J. Spencer 1:f5ac63519541 573 IPH_LEN_SET(&cs->cs_ip, htons((u_short)tmp));
Michael J. Spencer 1:f5ac63519541 574 #else
Michael J. Spencer 1:f5ac63519541 575 IPH_LEN_SET(&cs->cs_ip, htons(n0->tot_len - vjlen + cs->cs_hlen));
Michael J. Spencer 1:f5ac63519541 576 #endif
Michael J. Spencer 1:f5ac63519541 577
Michael J. Spencer 1:f5ac63519541 578 /* recompute the ip header checksum */
Michael J. Spencer 1:f5ac63519541 579 bp = (u_short *) &cs->cs_ip;
Michael J. Spencer 1:f5ac63519541 580 IPH_CHKSUM_SET(&cs->cs_ip, 0);
Michael J. Spencer 1:f5ac63519541 581 for (tmp = 0; hlen > 0; hlen -= 2) {
Michael J. Spencer 1:f5ac63519541 582 tmp += *bp++;
Michael J. Spencer 1:f5ac63519541 583 }
Michael J. Spencer 1:f5ac63519541 584 tmp = (tmp & 0xffff) + (tmp >> 16);
Michael J. Spencer 1:f5ac63519541 585 tmp = (tmp & 0xffff) + (tmp >> 16);
Michael J. Spencer 1:f5ac63519541 586 IPH_CHKSUM_SET(&cs->cs_ip, (u_short)(~tmp));
Michael J. Spencer 1:f5ac63519541 587
Michael J. Spencer 1:f5ac63519541 588 /* Remove the compressed header and prepend the uncompressed header. */
Michael J. Spencer 1:f5ac63519541 589 if(pbuf_header(n0, -((s16_t)(vjlen)))) {
Michael J. Spencer 1:f5ac63519541 590 /* Can we cope with this failing? Just assert for now */
Michael J. Spencer 1:f5ac63519541 591 LWIP_ASSERT("pbuf_header failed\n", 0);
Michael J. Spencer 1:f5ac63519541 592 goto bad;
Michael J. Spencer 1:f5ac63519541 593 }
Michael J. Spencer 1:f5ac63519541 594
Michael J. Spencer 1:f5ac63519541 595 if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) {
Michael J. Spencer 1:f5ac63519541 596 struct pbuf *np, *q;
Michael J. Spencer 1:f5ac63519541 597 u8_t *bufptr;
Michael J. Spencer 1:f5ac63519541 598
Michael J. Spencer 1:f5ac63519541 599 np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL);
Michael J. Spencer 1:f5ac63519541 600 if(!np) {
Michael J. Spencer 1:f5ac63519541 601 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n"));
Michael J. Spencer 1:f5ac63519541 602 goto bad;
Michael J. Spencer 1:f5ac63519541 603 }
Michael J. Spencer 1:f5ac63519541 604
Michael J. Spencer 1:f5ac63519541 605 if(pbuf_header(np, -cs->cs_hlen)) {
Michael J. Spencer 1:f5ac63519541 606 /* Can we cope with this failing? Just assert for now */
Michael J. Spencer 1:f5ac63519541 607 LWIP_ASSERT("pbuf_header failed\n", 0);
Michael J. Spencer 1:f5ac63519541 608 goto bad;
Michael J. Spencer 1:f5ac63519541 609 }
Michael J. Spencer 1:f5ac63519541 610
Michael J. Spencer 1:f5ac63519541 611 bufptr = (u8_t *)n0->payload;
Michael J. Spencer 1:f5ac63519541 612 for(q = np; q != NULL; q = q->next) {
Michael J. Spencer 1:f5ac63519541 613 MEMCPY(q->payload, bufptr, q->len);
Michael J. Spencer 1:f5ac63519541 614 bufptr += q->len;
Michael J. Spencer 1:f5ac63519541 615 }
Michael J. Spencer 1:f5ac63519541 616
Michael J. Spencer 1:f5ac63519541 617 if(n0->next) {
Michael J. Spencer 1:f5ac63519541 618 pbuf_chain(np, n0->next);
Michael J. Spencer 1:f5ac63519541 619 pbuf_dechain(n0);
Michael J. Spencer 1:f5ac63519541 620 }
Michael J. Spencer 1:f5ac63519541 621 pbuf_free(n0);
Michael J. Spencer 1:f5ac63519541 622 n0 = np;
Michael J. Spencer 1:f5ac63519541 623 }
Michael J. Spencer 1:f5ac63519541 624
Michael J. Spencer 1:f5ac63519541 625 if(pbuf_header(n0, cs->cs_hlen)) {
Michael J. Spencer 1:f5ac63519541 626 struct pbuf *np;
Michael J. Spencer 1:f5ac63519541 627
Michael J. Spencer 1:f5ac63519541 628 LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE);
Michael J. Spencer 1:f5ac63519541 629 np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL);
Michael J. Spencer 1:f5ac63519541 630 if(!np) {
Michael J. Spencer 1:f5ac63519541 631 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n"));
Michael J. Spencer 1:f5ac63519541 632 goto bad;
Michael J. Spencer 1:f5ac63519541 633 }
Michael J. Spencer 1:f5ac63519541 634 pbuf_cat(np, n0);
Michael J. Spencer 1:f5ac63519541 635 n0 = np;
Michael J. Spencer 1:f5ac63519541 636 }
Michael J. Spencer 1:f5ac63519541 637 LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen);
Michael J. Spencer 1:f5ac63519541 638 MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen);
Michael J. Spencer 1:f5ac63519541 639
Michael J. Spencer 1:f5ac63519541 640 *nb = n0;
Michael J. Spencer 1:f5ac63519541 641
Michael J. Spencer 1:f5ac63519541 642 return vjlen;
Michael J. Spencer 1:f5ac63519541 643
Michael J. Spencer 1:f5ac63519541 644 bad:
Michael J. Spencer 1:f5ac63519541 645 comp->flags |= VJF_TOSS;
Michael J. Spencer 1:f5ac63519541 646 INCR(vjs_errorin);
Michael J. Spencer 1:f5ac63519541 647 return (-1);
Michael J. Spencer 1:f5ac63519541 648 }
Michael J. Spencer 1:f5ac63519541 649
Michael J. Spencer 1:f5ac63519541 650 #endif /* VJ_SUPPORT */
Michael J. Spencer 1:f5ac63519541 651
Michael J. Spencer 1:f5ac63519541 652 #endif /* PPP_SUPPORT */