Marco Zecchini
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Example_RTOS
Rtos API example
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lwip_vj.c
00001 /* 00002 * Routines to compress and uncompess tcp packets (for transmission 00003 * over low speed serial lines. 00004 * 00005 * Copyright (c) 1989 Regents of the University of California. 00006 * All rights reserved. 00007 * 00008 * Redistribution and use in source and binary forms are permitted 00009 * provided that the above copyright notice and this paragraph are 00010 * duplicated in all such forms and that any documentation, 00011 * advertising materials, and other materials related to such 00012 * distribution and use acknowledge that the software was developed 00013 * by the University of California, Berkeley. The name of the 00014 * University may not be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 00017 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 00018 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 00019 * 00020 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 00021 * Initial distribution. 00022 * 00023 * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au, 00024 * so that the entire packet being decompressed doesn't have 00025 * to be in contiguous memory (just the compressed header). 00026 * 00027 * Modified March 1998 by Guy Lancaster, glanca@gesn.com, 00028 * for a 16 bit processor. 00029 */ 00030 00031 #include "netif/ppp/ppp_opts.h" 00032 #if PPP_SUPPORT && VJ_SUPPORT /* don't build if not configured for use in lwipopts.h */ 00033 00034 #include "netif/ppp/ppp_impl.h" 00035 #include "netif/ppp/pppdebug.h" 00036 00037 #include "netif/ppp/vj.h" 00038 00039 #include <string.h> 00040 00041 #if LINK_STATS 00042 #define INCR(counter) ++comp->stats.counter 00043 #else 00044 #define INCR(counter) 00045 #endif 00046 00047 void 00048 vj_compress_init(struct vjcompress *comp) 00049 { 00050 u8_t i; 00051 struct cstate *tstate = comp->tstate; 00052 00053 #if MAX_SLOTS == 0 00054 memset((char *)comp, 0, sizeof(*comp)); 00055 #endif 00056 comp->maxSlotIndex = MAX_SLOTS - 1; 00057 comp->compressSlot = 0; /* Disable slot ID compression by default. */ 00058 for (i = MAX_SLOTS - 1; i > 0; --i) { 00059 tstate[i].cs_id = i; 00060 tstate[i].cs_next = &tstate[i - 1]; 00061 } 00062 tstate[0].cs_next = &tstate[MAX_SLOTS - 1]; 00063 tstate[0].cs_id = 0; 00064 comp->last_cs = &tstate[0]; 00065 comp->last_recv = 255; 00066 comp->last_xmit = 255; 00067 comp->flags = VJF_TOSS; 00068 } 00069 00070 00071 /* ENCODE encodes a number that is known to be non-zero. ENCODEZ 00072 * checks for zero (since zero has to be encoded in the long, 3 byte 00073 * form). 00074 */ 00075 #define ENCODE(n) { \ 00076 if ((u16_t)(n) >= 256) { \ 00077 *cp++ = 0; \ 00078 cp[1] = (u8_t)(n); \ 00079 cp[0] = (u8_t)((n) >> 8); \ 00080 cp += 2; \ 00081 } else { \ 00082 *cp++ = (u8_t)(n); \ 00083 } \ 00084 } 00085 #define ENCODEZ(n) { \ 00086 if ((u16_t)(n) >= 256 || (u16_t)(n) == 0) { \ 00087 *cp++ = 0; \ 00088 cp[1] = (u8_t)(n); \ 00089 cp[0] = (u8_t)((n) >> 8); \ 00090 cp += 2; \ 00091 } else { \ 00092 *cp++ = (u8_t)(n); \ 00093 } \ 00094 } 00095 00096 #define DECODEL(f) { \ 00097 if (*cp == 0) {\ 00098 u32_t tmp_ = lwip_ntohl(f) + ((cp[1] << 8) | cp[2]); \ 00099 (f) = lwip_htonl(tmp_); \ 00100 cp += 3; \ 00101 } else { \ 00102 u32_t tmp_ = lwip_ntohl(f) + (u32_t)*cp++; \ 00103 (f) = lwip_htonl(tmp_); \ 00104 } \ 00105 } 00106 00107 #define DECODES(f) { \ 00108 if (*cp == 0) {\ 00109 u16_t tmp_ = lwip_ntohs(f) + (((u16_t)cp[1] << 8) | cp[2]); \ 00110 (f) = lwip_htons(tmp_); \ 00111 cp += 3; \ 00112 } else { \ 00113 u16_t tmp_ = lwip_ntohs(f) + (u16_t)*cp++; \ 00114 (f) = lwip_htons(tmp_); \ 00115 } \ 00116 } 00117 00118 #define DECODEU(f) { \ 00119 if (*cp == 0) {\ 00120 (f) = lwip_htons(((u16_t)cp[1] << 8) | cp[2]); \ 00121 cp += 3; \ 00122 } else { \ 00123 (f) = lwip_htons((u16_t)*cp++); \ 00124 } \ 00125 } 00126 00127 /* Helper structures for unaligned *u32_t and *u16_t accesses */ 00128 #ifdef PACK_STRUCT_USE_INCLUDES 00129 # include "arch/bpstruct.h" 00130 #endif 00131 PACK_STRUCT_BEGIN 00132 struct vj_u32_t { 00133 PACK_STRUCT_FIELD(u32_t v); 00134 } PACK_STRUCT_STRUCT; 00135 PACK_STRUCT_END 00136 #ifdef PACK_STRUCT_USE_INCLUDES 00137 # include "arch/epstruct.h" 00138 #endif 00139 00140 #ifdef PACK_STRUCT_USE_INCLUDES 00141 # include "arch/bpstruct.h" 00142 #endif 00143 PACK_STRUCT_BEGIN 00144 struct vj_u16_t { 00145 PACK_STRUCT_FIELD(u16_t v); 00146 } PACK_STRUCT_STRUCT; 00147 PACK_STRUCT_END 00148 #ifdef PACK_STRUCT_USE_INCLUDES 00149 # include "arch/epstruct.h" 00150 #endif 00151 00152 /* 00153 * vj_compress_tcp - Attempt to do Van Jacobson header compression on a 00154 * packet. This assumes that nb and comp are not null and that the first 00155 * buffer of the chain contains a valid IP header. 00156 * Return the VJ type code indicating whether or not the packet was 00157 * compressed. 00158 */ 00159 u8_t 00160 vj_compress_tcp(struct vjcompress *comp, struct pbuf **pb) 00161 { 00162 struct pbuf *np = *pb; 00163 struct ip_hdr *ip = (struct ip_hdr *)np->payload; 00164 struct cstate *cs = comp->last_cs->cs_next; 00165 u16_t ilen = IPH_HL(ip); 00166 u16_t hlen; 00167 struct tcp_hdr *oth; 00168 struct tcp_hdr *th; 00169 u16_t deltaS, deltaA = 0; 00170 u32_t deltaL; 00171 u32_t changes = 0; 00172 u8_t new_seq[16]; 00173 u8_t *cp = new_seq; 00174 00175 /* 00176 * Check that the packet is IP proto TCP. 00177 */ 00178 if (IPH_PROTO(ip) != IP_PROTO_TCP) { 00179 return (TYPE_IP); 00180 } 00181 00182 /* 00183 * Bail if this is an IP fragment or if the TCP packet isn't 00184 * `compressible' (i.e., ACK isn't set or some other control bit is 00185 * set). 00186 */ 00187 if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || np->tot_len < 40) { 00188 return (TYPE_IP); 00189 } 00190 th = (struct tcp_hdr *)&((struct vj_u32_t*)ip)[ilen]; 00191 if ((TCPH_FLAGS(th) & (TCP_SYN|TCP_FIN|TCP_RST|TCP_ACK)) != TCP_ACK) { 00192 return (TYPE_IP); 00193 } 00194 00195 /* Check that the TCP/IP headers are contained in the first buffer. */ 00196 hlen = ilen + TCPH_HDRLEN(th); 00197 hlen <<= 2; 00198 if (np->len < hlen) { 00199 PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen)); 00200 return (TYPE_IP); 00201 } 00202 00203 /* TCP stack requires that we don't change the packet payload, therefore we copy 00204 * the whole packet before compression. */ 00205 np = pbuf_alloc(PBUF_RAW, np->tot_len, PBUF_POOL); 00206 if (!np) { 00207 return (TYPE_IP); 00208 } 00209 00210 if (pbuf_copy(np, *pb) != ERR_OK) { 00211 pbuf_free(np); 00212 return (TYPE_IP); 00213 } 00214 00215 *pb = np; 00216 ip = (struct ip_hdr *)np->payload; 00217 00218 /* 00219 * Packet is compressible -- we're going to send either a 00220 * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need 00221 * to locate (or create) the connection state. Special case the 00222 * most recently used connection since it's most likely to be used 00223 * again & we don't have to do any reordering if it's used. 00224 */ 00225 INCR(vjs_packets); 00226 if (!ip4_addr_cmp(&ip->src, &cs->cs_ip.src) 00227 || !ip4_addr_cmp(&ip->dest, &cs->cs_ip.dest) 00228 || (*(struct vj_u32_t*)th).v != (((struct vj_u32_t*)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]).v) { 00229 /* 00230 * Wasn't the first -- search for it. 00231 * 00232 * States are kept in a circularly linked list with 00233 * last_cs pointing to the end of the list. The 00234 * list is kept in lru order by moving a state to the 00235 * head of the list whenever it is referenced. Since 00236 * the list is short and, empirically, the connection 00237 * we want is almost always near the front, we locate 00238 * states via linear search. If we don't find a state 00239 * for the datagram, the oldest state is (re-)used. 00240 */ 00241 struct cstate *lcs; 00242 struct cstate *lastcs = comp->last_cs; 00243 00244 do { 00245 lcs = cs; cs = cs->cs_next; 00246 INCR(vjs_searches); 00247 if (ip4_addr_cmp(&ip->src, &cs->cs_ip.src) 00248 && ip4_addr_cmp(&ip->dest, &cs->cs_ip.dest) 00249 && (*(struct vj_u32_t*)th).v == (((struct vj_u32_t*)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]).v) { 00250 goto found; 00251 } 00252 } while (cs != lastcs); 00253 00254 /* 00255 * Didn't find it -- re-use oldest cstate. Send an 00256 * uncompressed packet that tells the other side what 00257 * connection number we're using for this conversation. 00258 * Note that since the state list is circular, the oldest 00259 * state points to the newest and we only need to set 00260 * last_cs to update the lru linkage. 00261 */ 00262 INCR(vjs_misses); 00263 comp->last_cs = lcs; 00264 goto uncompressed; 00265 00266 found: 00267 /* 00268 * Found it -- move to the front on the connection list. 00269 */ 00270 if (cs == lastcs) { 00271 comp->last_cs = lcs; 00272 } else { 00273 lcs->cs_next = cs->cs_next; 00274 cs->cs_next = lastcs->cs_next; 00275 lastcs->cs_next = cs; 00276 } 00277 } 00278 00279 oth = (struct tcp_hdr *)&((struct vj_u32_t*)&cs->cs_ip)[ilen]; 00280 deltaS = ilen; 00281 00282 /* 00283 * Make sure that only what we expect to change changed. The first 00284 * line of the `if' checks the IP protocol version, header length & 00285 * type of service. The 2nd line checks the "Don't fragment" bit. 00286 * The 3rd line checks the time-to-live and protocol (the protocol 00287 * check is unnecessary but costless). The 4th line checks the TCP 00288 * header length. The 5th line checks IP options, if any. The 6th 00289 * line checks TCP options, if any. If any of these things are 00290 * different between the previous & current datagram, we send the 00291 * current datagram `uncompressed'. 00292 */ 00293 if ((((struct vj_u16_t*)ip)[0]).v != (((struct vj_u16_t*)&cs->cs_ip)[0]).v 00294 || (((struct vj_u16_t*)ip)[3]).v != (((struct vj_u16_t*)&cs->cs_ip)[3]).v 00295 || (((struct vj_u16_t*)ip)[4]).v != (((struct vj_u16_t*)&cs->cs_ip)[4]).v 00296 || TCPH_HDRLEN(th) != TCPH_HDRLEN(oth) 00297 || (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) 00298 || (TCPH_HDRLEN(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_HDRLEN(th) - 5) << 2))) { 00299 goto uncompressed; 00300 } 00301 00302 /* 00303 * Figure out which of the changing fields changed. The 00304 * receiver expects changes in the order: urgent, window, 00305 * ack, seq (the order minimizes the number of temporaries 00306 * needed in this section of code). 00307 */ 00308 if (TCPH_FLAGS(th) & TCP_URG) { 00309 deltaS = lwip_ntohs(th->urgp); 00310 ENCODEZ(deltaS); 00311 changes |= NEW_U; 00312 } else if (th->urgp != oth->urgp) { 00313 /* argh! URG not set but urp changed -- a sensible 00314 * implementation should never do this but RFC793 00315 * doesn't prohibit the change so we have to deal 00316 * with it. */ 00317 goto uncompressed; 00318 } 00319 00320 if ((deltaS = (u16_t)(lwip_ntohs(th->wnd) - lwip_ntohs(oth->wnd))) != 0) { 00321 ENCODE(deltaS); 00322 changes |= NEW_W; 00323 } 00324 00325 if ((deltaL = lwip_ntohl(th->ackno) - lwip_ntohl(oth->ackno)) != 0) { 00326 if (deltaL > 0xffff) { 00327 goto uncompressed; 00328 } 00329 deltaA = (u16_t)deltaL; 00330 ENCODE(deltaA); 00331 changes |= NEW_A; 00332 } 00333 00334 if ((deltaL = lwip_ntohl(th->seqno) - lwip_ntohl(oth->seqno)) != 0) { 00335 if (deltaL > 0xffff) { 00336 goto uncompressed; 00337 } 00338 deltaS = (u16_t)deltaL; 00339 ENCODE(deltaS); 00340 changes |= NEW_S; 00341 } 00342 00343 switch(changes) { 00344 case 0: 00345 /* 00346 * Nothing changed. If this packet contains data and the 00347 * last one didn't, this is probably a data packet following 00348 * an ack (normal on an interactive connection) and we send 00349 * it compressed. Otherwise it's probably a retransmit, 00350 * retransmitted ack or window probe. Send it uncompressed 00351 * in case the other side missed the compressed version. 00352 */ 00353 if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) && 00354 lwip_ntohs(IPH_LEN(&cs->cs_ip)) == hlen) { 00355 break; 00356 } 00357 /* no break */ 00358 /* fall through */ 00359 00360 case SPECIAL_I: 00361 case SPECIAL_D: 00362 /* 00363 * actual changes match one of our special case encodings -- 00364 * send packet uncompressed. 00365 */ 00366 goto uncompressed; 00367 00368 case NEW_S|NEW_A: 00369 if (deltaS == deltaA && deltaS == lwip_ntohs(IPH_LEN(&cs->cs_ip)) - hlen) { 00370 /* special case for echoed terminal traffic */ 00371 changes = SPECIAL_I; 00372 cp = new_seq; 00373 } 00374 break; 00375 00376 case NEW_S: 00377 if (deltaS == lwip_ntohs(IPH_LEN(&cs->cs_ip)) - hlen) { 00378 /* special case for data xfer */ 00379 changes = SPECIAL_D; 00380 cp = new_seq; 00381 } 00382 break; 00383 default: 00384 break; 00385 } 00386 00387 deltaS = (u16_t)(lwip_ntohs(IPH_ID(ip)) - lwip_ntohs(IPH_ID(&cs->cs_ip))); 00388 if (deltaS != 1) { 00389 ENCODEZ(deltaS); 00390 changes |= NEW_I; 00391 } 00392 if (TCPH_FLAGS(th) & TCP_PSH) { 00393 changes |= TCP_PUSH_BIT; 00394 } 00395 /* 00396 * Grab the cksum before we overwrite it below. Then update our 00397 * state with this packet's header. 00398 */ 00399 deltaA = lwip_ntohs(th->chksum); 00400 MEMCPY(&cs->cs_ip, ip, hlen); 00401 00402 /* 00403 * We want to use the original packet as our compressed packet. 00404 * (cp - new_seq) is the number of bytes we need for compressed 00405 * sequence numbers. In addition we need one byte for the change 00406 * mask, one for the connection id and two for the tcp checksum. 00407 * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how 00408 * many bytes of the original packet to toss so subtract the two to 00409 * get the new packet size. 00410 */ 00411 deltaS = (u16_t)(cp - new_seq); 00412 if (!comp->compressSlot || comp->last_xmit != cs->cs_id) { 00413 comp->last_xmit = cs->cs_id; 00414 hlen -= deltaS + 4; 00415 if (pbuf_header(np, -(s16_t)hlen)){ 00416 /* Can we cope with this failing? Just assert for now */ 00417 LWIP_ASSERT("pbuf_header failed\n", 0); 00418 } 00419 cp = (u8_t*)np->payload; 00420 *cp++ = (u8_t)(changes | NEW_C); 00421 *cp++ = cs->cs_id; 00422 } else { 00423 hlen -= deltaS + 3; 00424 if (pbuf_header(np, -(s16_t)hlen)) { 00425 /* Can we cope with this failing? Just assert for now */ 00426 LWIP_ASSERT("pbuf_header failed\n", 0); 00427 } 00428 cp = (u8_t*)np->payload; 00429 *cp++ = (u8_t)changes; 00430 } 00431 *cp++ = (u8_t)(deltaA >> 8); 00432 *cp++ = (u8_t)deltaA; 00433 MEMCPY(cp, new_seq, deltaS); 00434 INCR(vjs_compressed); 00435 return (TYPE_COMPRESSED_TCP); 00436 00437 /* 00438 * Update connection state cs & send uncompressed packet (that is, 00439 * a regular ip/tcp packet but with the 'conversation id' we hope 00440 * to use on future compressed packets in the protocol field). 00441 */ 00442 uncompressed: 00443 MEMCPY(&cs->cs_ip, ip, hlen); 00444 IPH_PROTO_SET(ip, cs->cs_id); 00445 comp->last_xmit = cs->cs_id; 00446 return (TYPE_UNCOMPRESSED_TCP); 00447 } 00448 00449 /* 00450 * Called when we may have missed a packet. 00451 */ 00452 void 00453 vj_uncompress_err(struct vjcompress *comp) 00454 { 00455 comp->flags |= VJF_TOSS; 00456 INCR(vjs_errorin); 00457 } 00458 00459 /* 00460 * "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP. 00461 * Return 0 on success, -1 on failure. 00462 */ 00463 int 00464 vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp) 00465 { 00466 u32_t hlen; 00467 struct cstate *cs; 00468 struct ip_hdr *ip; 00469 00470 ip = (struct ip_hdr *)nb->payload; 00471 hlen = IPH_HL(ip) << 2; 00472 if (IPH_PROTO(ip) >= MAX_SLOTS 00473 || hlen + sizeof(struct tcp_hdr) > nb->len 00474 || (hlen += TCPH_HDRLEN(((struct tcp_hdr *)&((char *)ip)[hlen])) << 2) 00475 > nb->len 00476 || hlen > MAX_HDR) { 00477 PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n", 00478 IPH_PROTO(ip), hlen, nb->len)); 00479 comp->flags |= VJF_TOSS; 00480 INCR(vjs_errorin); 00481 return -1; 00482 } 00483 cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)]; 00484 comp->flags &=~ VJF_TOSS; 00485 IPH_PROTO_SET(ip, IP_PROTO_TCP); 00486 MEMCPY(&cs->cs_ip, ip, hlen); 00487 cs->cs_hlen = (u16_t)hlen; 00488 INCR(vjs_uncompressedin); 00489 return 0; 00490 } 00491 00492 /* 00493 * Uncompress a packet of type TYPE_COMPRESSED_TCP. 00494 * The packet is composed of a buffer chain and the first buffer 00495 * must contain an accurate chain length. 00496 * The first buffer must include the entire compressed TCP/IP header. 00497 * This procedure replaces the compressed header with the uncompressed 00498 * header and returns the length of the VJ header. 00499 */ 00500 int 00501 vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp) 00502 { 00503 u8_t *cp; 00504 struct tcp_hdr *th; 00505 struct cstate *cs; 00506 struct vj_u16_t *bp; 00507 struct pbuf *n0 = *nb; 00508 u32_t tmp; 00509 u32_t vjlen, hlen, changes; 00510 00511 INCR(vjs_compressedin); 00512 cp = (u8_t*)n0->payload; 00513 changes = *cp++; 00514 if (changes & NEW_C) { 00515 /* 00516 * Make sure the state index is in range, then grab the state. 00517 * If we have a good state index, clear the 'discard' flag. 00518 */ 00519 if (*cp >= MAX_SLOTS) { 00520 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp)); 00521 goto bad; 00522 } 00523 00524 comp->flags &=~ VJF_TOSS; 00525 comp->last_recv = *cp++; 00526 } else { 00527 /* 00528 * this packet has an implicit state index. If we've 00529 * had a line error since the last time we got an 00530 * explicit state index, we have to toss the packet. 00531 */ 00532 if (comp->flags & VJF_TOSS) { 00533 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n")); 00534 INCR(vjs_tossed); 00535 return (-1); 00536 } 00537 } 00538 cs = &comp->rstate[comp->last_recv]; 00539 hlen = IPH_HL(&cs->cs_ip) << 2; 00540 th = (struct tcp_hdr *)&((u8_t*)&cs->cs_ip)[hlen]; 00541 th->chksum = lwip_htons((*cp << 8) | cp[1]); 00542 cp += 2; 00543 if (changes & TCP_PUSH_BIT) { 00544 TCPH_SET_FLAG(th, TCP_PSH); 00545 } else { 00546 TCPH_UNSET_FLAG(th, TCP_PSH); 00547 } 00548 00549 switch (changes & SPECIALS_MASK) { 00550 case SPECIAL_I: 00551 { 00552 u32_t i = lwip_ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen; 00553 /* some compilers can't nest inline assembler.. */ 00554 tmp = lwip_ntohl(th->ackno) + i; 00555 th->ackno = lwip_htonl(tmp); 00556 tmp = lwip_ntohl(th->seqno) + i; 00557 th->seqno = lwip_htonl(tmp); 00558 } 00559 break; 00560 00561 case SPECIAL_D: 00562 /* some compilers can't nest inline assembler.. */ 00563 tmp = lwip_ntohl(th->seqno) + lwip_ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen; 00564 th->seqno = lwip_htonl(tmp); 00565 break; 00566 00567 default: 00568 if (changes & NEW_U) { 00569 TCPH_SET_FLAG(th, TCP_URG); 00570 DECODEU(th->urgp); 00571 } else { 00572 TCPH_UNSET_FLAG(th, TCP_URG); 00573 } 00574 if (changes & NEW_W) { 00575 DECODES(th->wnd); 00576 } 00577 if (changes & NEW_A) { 00578 DECODEL(th->ackno); 00579 } 00580 if (changes & NEW_S) { 00581 DECODEL(th->seqno); 00582 } 00583 break; 00584 } 00585 if (changes & NEW_I) { 00586 DECODES(cs->cs_ip._id); 00587 } else { 00588 IPH_ID_SET(&cs->cs_ip, lwip_ntohs(IPH_ID(&cs->cs_ip)) + 1); 00589 IPH_ID_SET(&cs->cs_ip, lwip_htons(IPH_ID(&cs->cs_ip))); 00590 } 00591 00592 /* 00593 * At this point, cp points to the first byte of data in the 00594 * packet. Fill in the IP total length and update the IP 00595 * header checksum. 00596 */ 00597 vjlen = (u16_t)(cp - (u8_t*)n0->payload); 00598 if (n0->len < vjlen) { 00599 /* 00600 * We must have dropped some characters (crc should detect 00601 * this but the old slip framing won't) 00602 */ 00603 PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n", 00604 n0->len, vjlen)); 00605 goto bad; 00606 } 00607 00608 #if BYTE_ORDER == LITTLE_ENDIAN 00609 tmp = n0->tot_len - vjlen + cs->cs_hlen; 00610 IPH_LEN_SET(&cs->cs_ip, lwip_htons((u16_t)tmp)); 00611 #else 00612 IPH_LEN_SET(&cs->cs_ip, lwip_htons(n0->tot_len - vjlen + cs->cs_hlen)); 00613 #endif 00614 00615 /* recompute the ip header checksum */ 00616 bp = (struct vj_u16_t*) &cs->cs_ip; 00617 IPH_CHKSUM_SET(&cs->cs_ip, 0); 00618 for (tmp = 0; hlen > 0; hlen -= 2) { 00619 tmp += (*bp++).v; 00620 } 00621 tmp = (tmp & 0xffff) + (tmp >> 16); 00622 tmp = (tmp & 0xffff) + (tmp >> 16); 00623 IPH_CHKSUM_SET(&cs->cs_ip, (u16_t)(~tmp)); 00624 00625 /* Remove the compressed header and prepend the uncompressed header. */ 00626 if (pbuf_header(n0, -(s16_t)vjlen)) { 00627 /* Can we cope with this failing? Just assert for now */ 00628 LWIP_ASSERT("pbuf_header failed\n", 0); 00629 goto bad; 00630 } 00631 00632 if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) { 00633 struct pbuf *np, *q; 00634 u8_t *bufptr; 00635 00636 #if IP_FORWARD 00637 /* If IP forwarding is enabled we are using a PBUF_LINK packet type so 00638 * the packet is being allocated with enough header space to be 00639 * forwarded (to Ethernet for example). 00640 */ 00641 np = pbuf_alloc(PBUF_LINK, n0->len + cs->cs_hlen, PBUF_POOL); 00642 #else /* IP_FORWARD */ 00643 np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL); 00644 #endif /* IP_FORWARD */ 00645 if(!np) { 00646 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n")); 00647 goto bad; 00648 } 00649 00650 if (pbuf_header(np, -(s16_t)cs->cs_hlen)) { 00651 /* Can we cope with this failing? Just assert for now */ 00652 LWIP_ASSERT("pbuf_header failed\n", 0); 00653 goto bad; 00654 } 00655 00656 bufptr = (u8_t*)n0->payload; 00657 for(q = np; q != NULL; q = q->next) { 00658 MEMCPY(q->payload, bufptr, q->len); 00659 bufptr += q->len; 00660 } 00661 00662 if(n0->next) { 00663 pbuf_chain(np, n0->next); 00664 pbuf_dechain(n0); 00665 } 00666 pbuf_free(n0); 00667 n0 = np; 00668 } 00669 00670 if (pbuf_header(n0, (s16_t)cs->cs_hlen)) { 00671 struct pbuf *np; 00672 00673 LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE); 00674 np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL); 00675 if(!np) { 00676 PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n")); 00677 goto bad; 00678 } 00679 pbuf_cat(np, n0); 00680 n0 = np; 00681 } 00682 LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen); 00683 MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen); 00684 00685 *nb = n0; 00686 00687 return vjlen; 00688 00689 bad: 00690 comp->flags |= VJF_TOSS; 00691 INCR(vjs_errorin); 00692 return (-1); 00693 } 00694 00695 #endif /* PPP_SUPPORT && VJ_SUPPORT */
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