slcompress.c revision 36960
159769Sgrog/* 259769Sgrog * Routines to compress and uncompess tcp packets (for transmission 324424Swosch * over low speed serial lines. 424424Swosch * 524424Swosch * Copyright (c) 1989 Regents of the University of California. 624424Swosch * All rights reserved. 724424Swosch * 824424Swosch * Redistribution and use in source and binary forms are permitted 924424Swosch * provided that the above copyright notice and this paragraph are 1024424Swosch * duplicated in all such forms and that any documentation, 1124424Swosch * advertising materials, and other materials related to such 1224424Swosch * distribution and use acknowledge that the software was developed 1324424Swosch * by the University of California, Berkeley. The name of the 1424424Swosch * University may not be used to endorse or promote products derived 1542704Swosch * from this software without specific prior written permission. 1642704Swosch * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 1742704Swosch * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 1824424Swosch * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 1942704Swosch * 2042704Swosch * $Id: slcompress.c,v 1.16 1998/05/21 21:48:27 brian Exp $ 2142704Swosch * 2242704Swosch * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 2342704Swosch * - Initial distribution. 2442704Swosch */ 2542704Swosch 2642704Swosch#include <sys/types.h> 2742704Swosch#include <netinet/in_systm.h> 2842704Swosch#include <netinet/in.h> 2942704Swosch#include <netinet/tcp.h> 3059769Sgrog#include <netinet/ip.h> 3159769Sgrog#include <sys/un.h> 3259769Sgrog 3359769Sgrog#include <stdio.h> 3459769Sgrog#include <string.h> 3559769Sgrog#include <termios.h> 3659769Sgrog 3759769Sgrog#include "command.h" 3859769Sgrog#include "mbuf.h" 3924424Swosch#include "log.h" 4042704Swosch#include "defs.h" 4124424Swosch#include "slcompress.h" 4242704Swosch#include "descriptor.h" 4324424Swosch#include "prompt.h" 4442704Swosch#include "timer.h" 4524424Swosch#include "fsm.h" 4624424Swosch#include "throughput.h" 4724424Swosch#include "iplist.h" 4842704Swosch#include "ipcp.h" 4925031Swosch#include "filter.h" 5059156Swosch#include "lqr.h" 5125031Swosch#include "hdlc.h" 5225031Swosch#include "lcp.h" 5324424Swosch#include "ccp.h" 5424424Swosch#include "link.h" 5524424Swosch#include "mp.h" 5624424Swosch#include "bundle.h" 5771231Sitojun 5824424Swoschvoid 5971231Sitojunsl_compress_init(struct slcompress * comp, int max_state) 6025031Swosch{ 6171231Sitojun register u_int i; 6224424Swosch register struct cstate *tstate = comp->tstate; 6325031Swosch 6425031Swosch memset(comp, '\0', sizeof *comp); 6571231Sitojun for (i = max_state; i > 0; --i) { 6625031Swosch tstate[i].cs_id = i; 6771231Sitojun tstate[i].cs_next = &tstate[i - 1]; 6870110Swosch } 6970110Swosch tstate[0].cs_next = &tstate[max_state]; 7070110Swosch tstate[0].cs_id = 0; 7170110Swosch comp->last_cs = &tstate[0]; 7270110Swosch comp->last_recv = 255; 7370110Swosch comp->last_xmit = 255; 7470110Swosch comp->flags = SLF_TOSS; 7570110Swosch} 7670110Swosch 7770110Swosch 7870110Swosch/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 7970110Swosch * checks for zero (since zero has to be encoded in the long, 3 byte 8070110Swosch * form). 8170110Swosch */ 8270110Swosch#define ENCODE(n) { \ 8370110Swosch if ((u_short)(n) >= 256) { \ 8470110Swosch *cp++ = 0; \ 8570110Swosch cp[1] = (n); \ 8670110Swosch cp[0] = (n) >> 8; \ 8770110Swosch cp += 2; \ 8870110Swosch } else { \ 8970110Swosch *cp++ = (n); \ 9070110Swosch } \ 9170110Swosch} 9270110Swosch#define ENCODEZ(n) { \ 9370110Swosch if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 9470110Swosch *cp++ = 0; \ 9570110Swosch cp[1] = (n); \ 9670110Swosch cp[0] = (n) >> 8; \ 9770110Swosch cp += 2; \ 9870110Swosch } else { \ 9970110Swosch *cp++ = (n); \ 10070110Swosch } \ 10170110Swosch} 10270110Swosch 10370110Swosch#define DECODEL(f) { \ 10470110Swosch if (*cp == 0) {\ 10570110Swosch (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 10670110Swosch cp += 3; \ 10770110Swosch } else { \ 10870110Swosch (f) = htonl(ntohl(f) + (u_long)*cp++); \ 10970110Swosch } \ 11070110Swosch} 11170110Swosch 11270110Swosch#define DECODES(f) { \ 11370110Swosch if (*cp == 0) {\ 11470110Swosch (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 11570110Swosch cp += 3; \ 11670110Swosch } else { \ 11770110Swosch (f) = htons(ntohs(f) + (u_long)*cp++); \ 11870110Swosch } \ 11970110Swosch} 12070110Swosch 12170110Swosch#define DECODEU(f) { \ 12270110Swosch if (*cp == 0) {\ 12370110Swosch (f) = htons((cp[1] << 8) | cp[2]); \ 12470110Swosch cp += 3; \ 12570110Swosch } else { \ 12670110Swosch (f) = htons((u_long)*cp++); \ 12770110Swosch } \ 12870119Swosch} 12970119Swosch 13070119Swosch 13170119Swoschu_char 13270119Swoschsl_compress_tcp(struct mbuf * m, 13370119Swosch struct ip * ip, 13470119Swosch struct slcompress *comp, 13570119Swosch struct slstat *slstat, 13670119Swosch int compress_cid) 13771231Sitojun{ 13870119Swosch register struct cstate *cs = comp->last_cs->cs_next; 13970119Swosch register u_int hlen = ip->ip_hl; 14072877Swosch register struct tcphdr *oth; 14172877Swosch register struct tcphdr *th; 14272877Swosch register u_int deltaS, deltaA; 14372877Swosch register u_int changes = 0; 14465412Swosch u_char new_seq[16]; 14565412Swosch register u_char *cp = new_seq; 14665412Swosch 14765412Swosch /* 14824424Swosch * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 14924424Swosch * (i.e., ACK isn't set or some other control bit is set). (We assume that 15024424Swosch * the caller has already made sure the packet is IP proto TCP). 15124424Swosch */ 15224424Swosch if ((ip->ip_off & htons(0x3fff)) || m->cnt < 40) { 15369277Sasmodai log_Printf(LogDEBUG, "??? 1 ip_off = %x, cnt = %d\n", 15469277Sasmodai ip->ip_off, m->cnt); 15524424Swosch log_DumpBp(LogDEBUG, "", m); 15625031Swosch return (TYPE_IP); 15725031Swosch } 15825031Swosch th = (struct tcphdr *) & ((int *) ip)[hlen]; 15925031Swosch if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16025031Swosch log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 16125031Swosch log_DumpBp(LogDEBUG, "", m); 16225031Swosch return (TYPE_IP); 16325031Swosch } 16425031Swosch 16525031Swosch /* 16625031Swosch * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 16725031Swosch * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 16825031Swosch * connection state. Special case the most recently used connection since 16925031Swosch * it's most likely to be used again & we don't have to do any reordering 17025031Swosch * if it's used. 17138440Sjkh */ 17245349Swosch slstat->sls_packets++; 17345349Swosch if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 17442704Swosch ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 17570110Swosch *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 17625031Swosch 17724424Swosch /* 17859769Sgrog * Wasn't the first -- search for it. 17925031Swosch * 18025031Swosch * States are kept in a circularly linked list with last_cs pointing to the 18125031Swosch * end of the list. The list is kept in lru order by moving a state to 18225031Swosch * the head of the list whenever it is referenced. Since the list is 18359769Sgrog * short and, empirically, the connection we want is almost always near 18425031Swosch * the front, we locate states via linear search. If we don't find a 18525031Swosch * state for the datagram, the oldest state is (re-)used. 18625031Swosch */ 18725031Swosch register struct cstate *lcs; 18824424Swosch register struct cstate *lastcs = comp->last_cs; 18925031Swosch 19025031Swosch do { 19125031Swosch lcs = cs; 19225031Swosch cs = cs->cs_next; 19325031Swosch slstat->sls_searches++; 19459769Sgrog if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 19559769Sgrog && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 19642704Swosch && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 19742704Swosch goto found; 19842704Swosch } while (cs != lastcs); 19970110Swosch 20042704Swosch /* 20142704Swosch * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 20225031Swosch * that tells the other side what connection number we're using for this 20325031Swosch * conversation. Note that since the state list is circular, the oldest 20424424Swosch * state points to the newest and we only need to set last_cs to update 20525031Swosch * the lru linkage. 20625031Swosch */ 20725031Swosch slstat->sls_misses++; 20825031Swosch comp->last_cs = lcs; 20925031Swosch#define THOFFSET(th) (th->th_off) 21025031Swosch hlen += th->th_off; 21125031Swosch hlen <<= 2; 21225031Swosch if (hlen > m->cnt) 21325031Swosch return (TYPE_IP); 21424424Swosch goto uncompressed; 21525031Swosch 21625031Swoschfound: 21725031Swosch 21825031Swosch /* 21925031Swosch * Found it -- move to the front on the connection list. 22025031Swosch */ 22125031Swosch if (cs == lastcs) 22225031Swosch comp->last_cs = lcs; 22359156Swosch else { 22425031Swosch lcs->cs_next = cs->cs_next; 22525031Swosch cs->cs_next = lastcs->cs_next; 22625031Swosch lastcs->cs_next = cs; 22725031Swosch } 22825031Swosch } 22925031Swosch 23025031Swosch /* 23125031Swosch * Make sure that only what we expect to change changed. The first line of 23225031Swosch * the `if' checks the IP protocol version, header length & type of 23325031Swosch * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 23424424Swosch * checks the time-to-live and protocol (the protocol check is unnecessary 23525031Swosch * but costless). The 4th line checks the TCP header length. The 5th line 23625031Swosch * checks IP options, if any. The 6th line checks TCP options, if any. If 23725031Swosch * any of these things are different between the previous & current 23825031Swosch * datagram, we send the current datagram `uncompressed'. 23925031Swosch */ 24025031Swosch oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 24125031Swosch deltaS = hlen; 24225031Swosch hlen += th->th_off; 24370110Swosch hlen <<= 2; 24471231Sitojun if (hlen > m->cnt) 24570110Swosch return (TYPE_IP); 24625031Swosch 24771231Sitojun if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 24871231Sitojun ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 24969278Sasmodai ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 25025031Swosch THOFFSET(th) != THOFFSET(oth) || 25171231Sitojun (deltaS > 5 && 25270110Swosch memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 25371231Sitojun (THOFFSET(th) > 5 && 25470110Swosch memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 25570110Swosch goto uncompressed; 25671231Sitojun } 25770110Swosch 25857000Swosch /* 25925031Swosch * Figure out which of the changing fields changed. The receiver expects 26045349Swosch * changes in the order: urgent, window, ack, seq (the order minimizes the 26175732Swosch * number of temporaries needed in this section of code). 26271231Sitojun */ 26325031Swosch if (th->th_flags & TH_URG) { 26438440Sjkh deltaS = ntohs(th->th_urp); 26538440Sjkh ENCODEZ(deltaS); 26649392Swosch changes |= NEW_U; 26757000Swosch } else if (th->th_urp != oth->th_urp) { 26838440Sjkh 26938440Sjkh /* 27070110Swosch * argh! URG not set but urp changed -- a sensible implementation should 27169278Sasmodai * never do this but RFC793 doesn't prohibit the change so we have to 27270110Swosch * deal with it. 27325031Swosch */ 27425031Swosch goto uncompressed; 27569278Sasmodai } 27645349Swosch deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 27770110Swosch if (deltaS) { 27869278Sasmodai ENCODE(deltaS); 27945349Swosch changes |= NEW_W; 28045349Swosch } 28169278Sasmodai deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 28269278Sasmodai if (deltaA) { 28369278Sasmodai if (deltaA > 0xffff) { 28470110Swosch goto uncompressed; 28569278Sasmodai } 28669278Sasmodai ENCODE(deltaA); 28769278Sasmodai changes |= NEW_A; 28857000Swosch } 28945349Swosch deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29069277Sasmodai if (deltaS) { 29145349Swosch if (deltaS > 0xffff) { 29266542Sitojun goto uncompressed; 29369277Sasmodai } 29457000Swosch ENCODE(deltaS); 29570110Swosch changes |= NEW_S; 29645349Swosch } 29757000Swosch switch (changes) { 29869277Sasmodai 29970110Swosch case 0: 30070110Swosch 30142589Swosch /* 30270110Swosch * Nothing changed. If this packet contains data and the last one didn't, 30370110Swosch * this is probably a data packet following an ack (normal on an 30446321Swosch * interactive connection) and we send it compressed. Otherwise it's 30545349Swosch * probably a retransmit, retransmitted ack or window probe. Send it 30645349Swosch * uncompressed in case the other side missed the compressed version. 30757000Swosch */ 30846318Swosch if (ip->ip_len != cs->cs_ip.ip_len && 30970110Swosch ntohs(cs->cs_ip.ip_len) == hlen) 31056406Swosch break; 31155389Sbillf 31255389Sbillf /* (fall through) */ 31357000Swosch 31455389Sbillf case SPECIAL_I: 31555389Sbillf case SPECIAL_D: 31655389Sbillf 31770110Swosch /* 31858448Swosch * actual changes match one of our special case encodings -- send packet 31958448Swosch * uncompressed. 32065412Swosch */ 32164612Salex goto uncompressed; 32264612Salex 32365411Swosch case NEW_S | NEW_A: 32465974Swosch if (deltaS == deltaA && 32569277Sasmodai deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 32669277Sasmodai /* special case for echoed terminal traffic */ 32770119Swosch changes = SPECIAL_I; 32869277Sasmodai cp = new_seq; 32970111Swosch } 33075833Swosch break; 33124424Swosch 33225031Swosch case NEW_S: 33324424Swosch if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33424424Swosch /* special case for data xfer */ 33524424Swosch changes = SPECIAL_D; 33624424Swosch cp = new_seq; 33724424Swosch } 33824424Swosch break; 33924424Swosch } 34024424Swosch 34124424Swosch deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 34224424Swosch if (deltaS != 1) { 34324424Swosch ENCODEZ(deltaS); 34424424Swosch changes |= NEW_I; 34524424Swosch } 34624424Swosch if (th->th_flags & TH_PUSH) 34725031Swosch changes |= TCP_PUSH_BIT; 34825031Swosch 34924424Swosch /* 35024424Swosch * Grab the cksum before we overwrite it below. Then update our state with 35124424Swosch * this packet's header. 35224424Swosch */ 35359769Sgrog deltaA = ntohs(th->th_sum); 35424424Swosch memcpy(&cs->cs_ip, ip, hlen); 35524424Swosch 35625031Swosch /* 35725031Swosch * We want to use the original packet as our compressed packet. (cp - 35825031Swosch * new_seq) is the number of bytes we need for compressed sequence numbers. 35925031Swosch * In addition we need one byte for the change mask, one for the connection 36059769Sgrog * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 36125031Swosch * are needed. hlen is how many bytes of the original packet to toss so 36231658Swosch * subtract the two to get the new packet size. 36359769Sgrog */ 36431658Swosch deltaS = cp - new_seq; 36559769Sgrog cp = (u_char *) ip; 36659769Sgrog 36759769Sgrog /* 36865415Swosch * Since fastq traffic can jump ahead of the background traffic, we don't 36965415Swosch * know what order packets will go on the line. In this case, we always 37065415Swosch * send a "new" connection id so the receiver state stays synchronized. 37175834Swosch */ 37275834Swosch if (comp->last_xmit == cs->cs_id && compress_cid) { 37375834Swosch hlen -= deltaS + 3; 37475834Swosch cp += hlen; 37575834Swosch *cp++ = changes; 37625031Swosch } else { 37725031Swosch comp->last_xmit = cs->cs_id; 37825031Swosch hlen -= deltaS + 4; 37959769Sgrog cp += hlen; 38025031Swosch *cp++ = changes | NEW_C; 38125031Swosch *cp++ = cs->cs_id; 38231658Swosch } 38325031Swosch m->cnt -= hlen; 38424424Swosch m->offset += hlen; 38572877Swosch *cp++ = deltaA >> 8; 38667388Swosch *cp++ = deltaA; 38742589Swosch memcpy(cp, new_seq, deltaS); 38850970Speter slstat->sls_compressed++; 38959769Sgrog return (TYPE_COMPRESSED_TCP); 390 391 /* 392 * Update connection state cs & send uncompressed packet ('uncompressed' 393 * means a regular ip/tcp packet but with the 'conversation id' we hope to 394 * use on future compressed packets in the protocol field). 395 */ 396uncompressed: 397 memcpy(&cs->cs_ip, ip, hlen); 398 ip->ip_p = cs->cs_id; 399 comp->last_xmit = cs->cs_id; 400 return (TYPE_UNCOMPRESSED_TCP); 401} 402 403 404int 405sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 406 struct slstat *slstat, int max_state) 407{ 408 register u_char *cp; 409 register u_int hlen, changes; 410 register struct tcphdr *th; 411 register struct cstate *cs; 412 register struct ip *ip; 413 414 switch (type) { 415 416 case TYPE_UNCOMPRESSED_TCP: 417 ip = (struct ip *) * bufp; 418 if (ip->ip_p > max_state) 419 goto bad; 420 cs = &comp->rstate[comp->last_recv = ip->ip_p]; 421 comp->flags &= ~SLF_TOSS; 422 ip->ip_p = IPPROTO_TCP; 423 424 /* 425 * Calculate the size of the TCP/IP header and make sure that we don't 426 * overflow the space we have available for it. 427 */ 428 hlen = ip->ip_hl << 2; 429 if (hlen + sizeof(struct tcphdr) > len) 430 goto bad; 431 th = (struct tcphdr *) & ((char *) ip)[hlen]; 432 hlen += THOFFSET(th) << 2; 433 if (hlen > MAX_HDR) 434 goto bad; 435 memcpy(&cs->cs_ip, ip, hlen); 436 cs->cs_ip.ip_sum = 0; 437 cs->cs_hlen = hlen; 438 slstat->sls_uncompressedin++; 439 return (len); 440 441 default: 442 goto bad; 443 444 case TYPE_COMPRESSED_TCP: 445 break; 446 } 447 /* We've got a compressed packet. */ 448 slstat->sls_compressedin++; 449 cp = *bufp; 450 changes = *cp++; 451 log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 452 if (changes & NEW_C) { 453 454 /* 455 * Make sure the state index is in range, then grab the state. If we have 456 * a good state index, clear the 'discard' flag. 457 */ 458 if (*cp > max_state || comp->last_recv == 255) { 459 goto bad; 460 } 461 462 comp->flags &= ~SLF_TOSS; 463 comp->last_recv = *cp++; 464 } else { 465 466 /* 467 * this packet has an implicit state index. If we've had a line error 468 * since the last time we got an explicit state index, we have to toss 469 * the packet. 470 */ 471 if (comp->flags & SLF_TOSS) { 472 slstat->sls_tossed++; 473 return (0); 474 } 475 } 476 cs = &comp->rstate[comp->last_recv]; 477 hlen = cs->cs_ip.ip_hl << 2; 478 if (hlen == 0) 479 goto bad; /* We've been pointed at a not-yet-used slot ! */ 480 th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 481 th->th_sum = htons((*cp << 8) | cp[1]); 482 cp += 2; 483 if (changes & TCP_PUSH_BIT) 484 th->th_flags |= TH_PUSH; 485 else 486 th->th_flags &= ~TH_PUSH; 487 488 switch (changes & SPECIALS_MASK) { 489 case SPECIAL_I: 490 { 491 register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 492 493 th->th_ack = htonl(ntohl(th->th_ack) + i); 494 th->th_seq = htonl(ntohl(th->th_seq) + i); 495 } 496 break; 497 498 case SPECIAL_D: 499 th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 500 - cs->cs_hlen); 501 break; 502 503 default: 504 if (changes & NEW_U) { 505 th->th_flags |= TH_URG; 506 DECODEU(th->th_urp) 507 } else 508 th->th_flags &= ~TH_URG; 509 if (changes & NEW_W) 510 DECODES(th->th_win) 511 if (changes & NEW_A) 512 DECODEL(th->th_ack) 513 if (changes & NEW_S) { 514 log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 515 *cp, cp[1], cp[2]); 516 DECODEL(th->th_seq) 517 } 518 break; 519 } 520 if (changes & NEW_I) { 521 DECODES(cs->cs_ip.ip_id) 522 } else 523 cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 524 525 log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 526 cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 527 528 /* 529 * At this point, cp points to the first byte of data in the packet. If 530 * we're not aligned on a 4-byte boundary, copy the data down so the ip & 531 * tcp headers will be aligned. Then back up cp by the tcp/ip header 532 * length to make room for the reconstructed header (we assume the packet 533 * we were handed has enough space to prepend 128 bytes of header). Adjust 534 * the length to account for the new header & fill in the IP total length. 535 */ 536 len -= (cp - *bufp); 537 if (len < 0) 538 539 /* 540 * we must have dropped some characters (crc should detect this but the 541 * old slip framing won't) 542 */ 543 goto bad; 544 545#ifdef notdef 546 if ((int) cp & 3) { 547 if (len > 0) 548 (void) bcopy(cp, (caddr_t) ((int) cp & ~3), len); 549 cp = (u_char *) ((int) cp & ~3); 550 } 551#endif 552 553 cp -= cs->cs_hlen; 554 len += cs->cs_hlen; 555 cs->cs_ip.ip_len = htons(len); 556 memcpy(cp, &cs->cs_ip, cs->cs_hlen); 557 *bufp = cp; 558 559 /* recompute the ip header checksum */ 560 { 561 register u_short *bp = (u_short *) cp; 562 563 for (changes = 0; hlen > 0; hlen -= 2) 564 changes += *bp++; 565 changes = (changes & 0xffff) + (changes >> 16); 566 changes = (changes & 0xffff) + (changes >> 16); 567 ((struct ip *) cp)->ip_sum = ~changes; 568 } 569 return (len); 570bad: 571 comp->flags |= SLF_TOSS; 572 slstat->sls_errorin++; 573 return (0); 574} 575 576int 577sl_Show(struct cmdargs const *arg) 578{ 579 prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 580 prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 581 arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 582 arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 583 prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 584 arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 585 arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 586 prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 587 arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 588 arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 589 prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 590 arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 591 arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 592 return 0; 593} 594