source: UsbWattMeter/trunk/lwip-1.4.1/src/netif/ppp/vj.c@ 164

Last change on this file since 164 was 164, checked in by coas-nagasima, 6 years ago

TOPPERS/ECNLサンプルアプリ「USB充電器電力計」を追加

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