slcompress.c revision 43313
16059Samurai/* 26059Samurai * Routines to compress and uncompess tcp packets (for transmission 36059Samurai * over low speed serial lines. 46059Samurai * 56059Samurai * Copyright (c) 1989 Regents of the University of California. 66059Samurai * All rights reserved. 76059Samurai * 86059Samurai * Redistribution and use in source and binary forms are permitted 96059Samurai * provided that the above copyright notice and this paragraph are 106059Samurai * duplicated in all such forms and that any documentation, 116059Samurai * advertising materials, and other materials related to such 126059Samurai * distribution and use acknowledge that the software was developed 136059Samurai * by the University of California, Berkeley. The name of the 146059Samurai * University may not be used to endorse or promote products derived 156059Samurai * from this software without specific prior written permission. 166059Samurai * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 176059Samurai * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 186059Samurai * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 196059Samurai * 2043313Sbrian * $Id: slcompress.c,v 1.20 1998/08/26 17:39:37 brian Exp $ 218857Srgrimes * 226059Samurai * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 236059Samurai * - Initial distribution. 246059Samurai */ 2528679Sbrian 2643313Sbrian#include <sys/param.h> 276059Samurai#include <netinet/in_systm.h> 286059Samurai#include <netinet/in.h> 296059Samurai#include <netinet/tcp.h> 306059Samurai#include <netinet/ip.h> 3136285Sbrian#include <sys/un.h> 3230715Sbrian 3330715Sbrian#include <stdio.h> 3430715Sbrian#include <string.h> 3536285Sbrian#include <termios.h> 3630715Sbrian 3737009Sbrian#include "defs.h" 3831343Sbrian#include "command.h" 3930715Sbrian#include "mbuf.h" 4030715Sbrian#include "log.h" 416059Samurai#include "slcompress.h" 4236285Sbrian#include "descriptor.h" 4336285Sbrian#include "prompt.h" 4436285Sbrian#include "timer.h" 4536285Sbrian#include "fsm.h" 4636285Sbrian#include "throughput.h" 4736285Sbrian#include "iplist.h" 4838557Sbrian#include "lqr.h" 4938557Sbrian#include "hdlc.h" 5036285Sbrian#include "ipcp.h" 5136285Sbrian#include "filter.h" 5236285Sbrian#include "lcp.h" 5336285Sbrian#include "ccp.h" 5436285Sbrian#include "link.h" 5536285Sbrian#include "mp.h" 5643313Sbrian#ifndef NORADIUS 5743313Sbrian#include "radius.h" 5843313Sbrian#endif 5936285Sbrian#include "bundle.h" 606059Samurai 616059Samuraivoid 6230187Sbriansl_compress_init(struct slcompress * comp, int max_state) 636059Samurai{ 6428679Sbrian register u_int i; 6528679Sbrian register struct cstate *tstate = comp->tstate; 666059Samurai 6731962Sbrian memset(comp, '\0', sizeof *comp); 6830187Sbrian for (i = max_state; i > 0; --i) { 6928679Sbrian tstate[i].cs_id = i; 7028679Sbrian tstate[i].cs_next = &tstate[i - 1]; 7128679Sbrian } 7230187Sbrian tstate[0].cs_next = &tstate[max_state]; 7328679Sbrian tstate[0].cs_id = 0; 7428679Sbrian comp->last_cs = &tstate[0]; 7528679Sbrian comp->last_recv = 255; 7628679Sbrian comp->last_xmit = 255; 7728679Sbrian comp->flags = SLF_TOSS; 786059Samurai} 796059Samurai 806059Samurai 816059Samurai/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 8237189Sbrian * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 836059Samurai * form). 846059Samurai */ 856059Samurai#define ENCODE(n) { \ 866059Samurai if ((u_short)(n) >= 256) { \ 876059Samurai *cp++ = 0; \ 886059Samurai cp[1] = (n); \ 896059Samurai cp[0] = (n) >> 8; \ 906059Samurai cp += 2; \ 916059Samurai } else { \ 926059Samurai *cp++ = (n); \ 936059Samurai } \ 946059Samurai} 956059Samurai#define ENCODEZ(n) { \ 966059Samurai if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 976059Samurai *cp++ = 0; \ 986059Samurai cp[1] = (n); \ 996059Samurai cp[0] = (n) >> 8; \ 1006059Samurai cp += 2; \ 1016059Samurai } else { \ 1026059Samurai *cp++ = (n); \ 1036059Samurai } \ 1046059Samurai} 1056059Samurai 1066059Samurai#define DECODEL(f) { \ 1076059Samurai if (*cp == 0) {\ 1086059Samurai (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 1096059Samurai cp += 3; \ 1106059Samurai } else { \ 11137189Sbrian (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 1126059Samurai } \ 1136059Samurai} 1146059Samurai 1156059Samurai#define DECODES(f) { \ 1166059Samurai if (*cp == 0) {\ 1176059Samurai (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 1186059Samurai cp += 3; \ 1196059Samurai } else { \ 12037189Sbrian (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 1216059Samurai } \ 1226059Samurai} 1236059Samurai 1246059Samurai#define DECODEU(f) { \ 1256059Samurai if (*cp == 0) {\ 1266059Samurai (f) = htons((cp[1] << 8) | cp[2]); \ 1276059Samurai cp += 3; \ 1286059Samurai } else { \ 12937189Sbrian (f) = htons((u_int32_t)*cp++); \ 1306059Samurai } \ 1316059Samurai} 1326059Samurai 1336059Samurai 1346059Samuraiu_char 13528679Sbriansl_compress_tcp(struct mbuf * m, 13628679Sbrian struct ip * ip, 13736285Sbrian struct slcompress *comp, 13836285Sbrian struct slstat *slstat, 13928679Sbrian int compress_cid) 1406059Samurai{ 14128679Sbrian register struct cstate *cs = comp->last_cs->cs_next; 14228679Sbrian register u_int hlen = ip->ip_hl; 14328679Sbrian register struct tcphdr *oth; 14428679Sbrian register struct tcphdr *th; 14528679Sbrian register u_int deltaS, deltaA; 14628679Sbrian register u_int changes = 0; 14728679Sbrian u_char new_seq[16]; 14828679Sbrian register u_char *cp = new_seq; 1496059Samurai 15028679Sbrian /* 15128679Sbrian * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 15228679Sbrian * (i.e., ACK isn't set or some other control bit is set). (We assume that 15328679Sbrian * the caller has already made sure the packet is IP proto TCP). 15428679Sbrian */ 15528679Sbrian if ((ip->ip_off & htons(0x3fff)) || m->cnt < 40) { 15636285Sbrian log_Printf(LogDEBUG, "??? 1 ip_off = %x, cnt = %d\n", 15728679Sbrian ip->ip_off, m->cnt); 15836285Sbrian log_DumpBp(LogDEBUG, "", m); 15928679Sbrian return (TYPE_IP); 16028679Sbrian } 16128679Sbrian th = (struct tcphdr *) & ((int *) ip)[hlen]; 16228679Sbrian if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16336285Sbrian log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 16436285Sbrian log_DumpBp(LogDEBUG, "", m); 16528679Sbrian return (TYPE_IP); 16628679Sbrian } 1676059Samurai 16828679Sbrian /* 16928679Sbrian * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 17028679Sbrian * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 17128679Sbrian * connection state. Special case the most recently used connection since 17228679Sbrian * it's most likely to be used again & we don't have to do any reordering 17328679Sbrian * if it's used. 17428679Sbrian */ 17536285Sbrian slstat->sls_packets++; 17636285Sbrian if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 17736285Sbrian ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 17836285Sbrian *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 1796059Samurai 18028679Sbrian /* 18128679Sbrian * Wasn't the first -- search for it. 18228679Sbrian * 18328679Sbrian * States are kept in a circularly linked list with last_cs pointing to the 18428679Sbrian * end of the list. The list is kept in lru order by moving a state to 18528679Sbrian * the head of the list whenever it is referenced. Since the list is 18628679Sbrian * short and, empirically, the connection we want is almost always near 18728679Sbrian * the front, we locate states via linear search. If we don't find a 18828679Sbrian * state for the datagram, the oldest state is (re-)used. 18928679Sbrian */ 19028679Sbrian register struct cstate *lcs; 19128679Sbrian register struct cstate *lastcs = comp->last_cs; 1926059Samurai 19328679Sbrian do { 19428679Sbrian lcs = cs; 19528679Sbrian cs = cs->cs_next; 19636285Sbrian slstat->sls_searches++; 19736285Sbrian if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 19836285Sbrian && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 19936285Sbrian && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 20028679Sbrian goto found; 20128679Sbrian } while (cs != lastcs); 2026059Samurai 20328679Sbrian /* 20428679Sbrian * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 20528679Sbrian * that tells the other side what connection number we're using for this 20628679Sbrian * conversation. Note that since the state list is circular, the oldest 20728679Sbrian * state points to the newest and we only need to set last_cs to update 20828679Sbrian * the lru linkage. 20928679Sbrian */ 21036285Sbrian slstat->sls_misses++; 21128679Sbrian comp->last_cs = lcs; 2126059Samurai#define THOFFSET(th) (th->th_off) 21328679Sbrian hlen += th->th_off; 21428679Sbrian hlen <<= 2; 21528679Sbrian if (hlen > m->cnt) 21628679Sbrian return (TYPE_IP); 21728679Sbrian goto uncompressed; 2186059Samurai 21928679Sbrianfound: 2206059Samurai 22128679Sbrian /* 22228679Sbrian * Found it -- move to the front on the connection list. 22328679Sbrian */ 22428679Sbrian if (cs == lastcs) 22528679Sbrian comp->last_cs = lcs; 22628679Sbrian else { 22728679Sbrian lcs->cs_next = cs->cs_next; 22828679Sbrian cs->cs_next = lastcs->cs_next; 22928679Sbrian lastcs->cs_next = cs; 23028679Sbrian } 23128679Sbrian } 2326059Samurai 23328679Sbrian /* 23428679Sbrian * Make sure that only what we expect to change changed. The first line of 23528679Sbrian * the `if' checks the IP protocol version, header length & type of 23628679Sbrian * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 23728679Sbrian * checks the time-to-live and protocol (the protocol check is unnecessary 23828679Sbrian * but costless). The 4th line checks the TCP header length. The 5th line 23928679Sbrian * checks IP options, if any. The 6th line checks TCP options, if any. If 24028679Sbrian * any of these things are different between the previous & current 24128679Sbrian * datagram, we send the current datagram `uncompressed'. 24228679Sbrian */ 24328679Sbrian oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 24428679Sbrian deltaS = hlen; 24528679Sbrian hlen += th->th_off; 24628679Sbrian hlen <<= 2; 24728679Sbrian if (hlen > m->cnt) 24828679Sbrian return (TYPE_IP); 2496059Samurai 25028679Sbrian if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 25128679Sbrian ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 25228679Sbrian ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 25328679Sbrian THOFFSET(th) != THOFFSET(oth) || 25428679Sbrian (deltaS > 5 && 25530715Sbrian memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 25628679Sbrian (THOFFSET(th) > 5 && 25730715Sbrian memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 25828679Sbrian goto uncompressed; 25928679Sbrian } 2606059Samurai 26128679Sbrian /* 26228679Sbrian * Figure out which of the changing fields changed. The receiver expects 26328679Sbrian * changes in the order: urgent, window, ack, seq (the order minimizes the 26428679Sbrian * number of temporaries needed in this section of code). 26528679Sbrian */ 26628679Sbrian if (th->th_flags & TH_URG) { 26728679Sbrian deltaS = ntohs(th->th_urp); 26828679Sbrian ENCODEZ(deltaS); 26928679Sbrian changes |= NEW_U; 27028679Sbrian } else if (th->th_urp != oth->th_urp) { 2716059Samurai 27228679Sbrian /* 27328679Sbrian * argh! URG not set but urp changed -- a sensible implementation should 27428679Sbrian * never do this but RFC793 doesn't prohibit the change so we have to 27528679Sbrian * deal with it. 27628679Sbrian */ 27728679Sbrian goto uncompressed; 27828679Sbrian } 27928679Sbrian deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 28028679Sbrian if (deltaS) { 28128679Sbrian ENCODE(deltaS); 28228679Sbrian changes |= NEW_W; 28328679Sbrian } 28428679Sbrian deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 28528679Sbrian if (deltaA) { 28628679Sbrian if (deltaA > 0xffff) { 28728679Sbrian goto uncompressed; 28828679Sbrian } 28928679Sbrian ENCODE(deltaA); 29028679Sbrian changes |= NEW_A; 29128679Sbrian } 29228679Sbrian deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29328679Sbrian if (deltaS) { 29428679Sbrian if (deltaS > 0xffff) { 29528679Sbrian goto uncompressed; 29628679Sbrian } 29728679Sbrian ENCODE(deltaS); 29828679Sbrian changes |= NEW_S; 29928679Sbrian } 30028679Sbrian switch (changes) { 3016059Samurai 30228679Sbrian case 0: 3036059Samurai 30428679Sbrian /* 30528679Sbrian * Nothing changed. If this packet contains data and the last one didn't, 30628679Sbrian * this is probably a data packet following an ack (normal on an 30728679Sbrian * interactive connection) and we send it compressed. Otherwise it's 30828679Sbrian * probably a retransmit, retransmitted ack or window probe. Send it 30928679Sbrian * uncompressed in case the other side missed the compressed version. 31028679Sbrian */ 31128679Sbrian if (ip->ip_len != cs->cs_ip.ip_len && 31228679Sbrian ntohs(cs->cs_ip.ip_len) == hlen) 31328679Sbrian break; 3146059Samurai 31528679Sbrian /* (fall through) */ 3166059Samurai 31728679Sbrian case SPECIAL_I: 31828679Sbrian case SPECIAL_D: 3196059Samurai 32028679Sbrian /* 32128679Sbrian * actual changes match one of our special case encodings -- send packet 32228679Sbrian * uncompressed. 32328679Sbrian */ 32428679Sbrian goto uncompressed; 3256059Samurai 32628679Sbrian case NEW_S | NEW_A: 32728679Sbrian if (deltaS == deltaA && 32828679Sbrian deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 32928679Sbrian /* special case for echoed terminal traffic */ 33028679Sbrian changes = SPECIAL_I; 33128679Sbrian cp = new_seq; 33228679Sbrian } 33328679Sbrian break; 3346059Samurai 33528679Sbrian case NEW_S: 33628679Sbrian if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33728679Sbrian /* special case for data xfer */ 33828679Sbrian changes = SPECIAL_D; 33928679Sbrian cp = new_seq; 34028679Sbrian } 34128679Sbrian break; 34228679Sbrian } 3436059Samurai 34428679Sbrian deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 34528679Sbrian if (deltaS != 1) { 34628679Sbrian ENCODEZ(deltaS); 34728679Sbrian changes |= NEW_I; 34828679Sbrian } 34928679Sbrian if (th->th_flags & TH_PUSH) 35028679Sbrian changes |= TCP_PUSH_BIT; 3516059Samurai 35228679Sbrian /* 35328679Sbrian * Grab the cksum before we overwrite it below. Then update our state with 35428679Sbrian * this packet's header. 35528679Sbrian */ 35628679Sbrian deltaA = ntohs(th->th_sum); 35730715Sbrian memcpy(&cs->cs_ip, ip, hlen); 3586059Samurai 35928679Sbrian /* 36028679Sbrian * We want to use the original packet as our compressed packet. (cp - 36128679Sbrian * new_seq) is the number of bytes we need for compressed sequence numbers. 36228679Sbrian * In addition we need one byte for the change mask, one for the connection 36328679Sbrian * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 36428679Sbrian * are needed. hlen is how many bytes of the original packet to toss so 36528679Sbrian * subtract the two to get the new packet size. 36628679Sbrian */ 36728679Sbrian deltaS = cp - new_seq; 36828679Sbrian cp = (u_char *) ip; 36928679Sbrian 37028679Sbrian /* 37128679Sbrian * Since fastq traffic can jump ahead of the background traffic, we don't 37228679Sbrian * know what order packets will go on the line. In this case, we always 37328679Sbrian * send a "new" connection id so the receiver state stays synchronized. 37428679Sbrian */ 37530187Sbrian if (comp->last_xmit == cs->cs_id && compress_cid) { 37628679Sbrian hlen -= deltaS + 3; 37728679Sbrian cp += hlen; 37828679Sbrian *cp++ = changes; 37930187Sbrian } else { 38028679Sbrian comp->last_xmit = cs->cs_id; 38128679Sbrian hlen -= deltaS + 4; 38228679Sbrian cp += hlen; 38328679Sbrian *cp++ = changes | NEW_C; 38428679Sbrian *cp++ = cs->cs_id; 38528679Sbrian } 38628679Sbrian m->cnt -= hlen; 38728679Sbrian m->offset += hlen; 38828679Sbrian *cp++ = deltaA >> 8; 38928679Sbrian *cp++ = deltaA; 39030715Sbrian memcpy(cp, new_seq, deltaS); 39136285Sbrian slstat->sls_compressed++; 39236285Sbrian return (TYPE_COMPRESSED_TCP); 3936059Samurai 39428679Sbrian /* 39528679Sbrian * Update connection state cs & send uncompressed packet ('uncompressed' 39628679Sbrian * means a regular ip/tcp packet but with the 'conversation id' we hope to 39728679Sbrian * use on future compressed packets in the protocol field). 39828679Sbrian */ 3996059Samuraiuncompressed: 40030715Sbrian memcpy(&cs->cs_ip, ip, hlen); 40128679Sbrian ip->ip_p = cs->cs_id; 40228679Sbrian comp->last_xmit = cs->cs_id; 40328679Sbrian return (TYPE_UNCOMPRESSED_TCP); 4046059Samurai} 4056059Samurai 4066059Samurai 4076059Samuraiint 40836960Sbriansl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 40936960Sbrian struct slstat *slstat, int max_state) 4106059Samurai{ 41128679Sbrian register u_char *cp; 41228679Sbrian register u_int hlen, changes; 41328679Sbrian register struct tcphdr *th; 41428679Sbrian register struct cstate *cs; 41528679Sbrian register struct ip *ip; 4166059Samurai 41728679Sbrian switch (type) { 4186059Samurai 41928679Sbrian case TYPE_UNCOMPRESSED_TCP: 42028679Sbrian ip = (struct ip *) * bufp; 42136960Sbrian if (ip->ip_p > max_state) 42228679Sbrian goto bad; 42328679Sbrian cs = &comp->rstate[comp->last_recv = ip->ip_p]; 42428679Sbrian comp->flags &= ~SLF_TOSS; 42528679Sbrian ip->ip_p = IPPROTO_TCP; 4266059Samurai 42728679Sbrian /* 42828679Sbrian * Calculate the size of the TCP/IP header and make sure that we don't 42928679Sbrian * overflow the space we have available for it. 43028679Sbrian */ 43128679Sbrian hlen = ip->ip_hl << 2; 43228679Sbrian if (hlen + sizeof(struct tcphdr) > len) 43328679Sbrian goto bad; 43428679Sbrian th = (struct tcphdr *) & ((char *) ip)[hlen]; 43528679Sbrian hlen += THOFFSET(th) << 2; 43628679Sbrian if (hlen > MAX_HDR) 43728679Sbrian goto bad; 43830715Sbrian memcpy(&cs->cs_ip, ip, hlen); 43930357Sbrian cs->cs_ip.ip_sum = 0; 44028679Sbrian cs->cs_hlen = hlen; 44136285Sbrian slstat->sls_uncompressedin++; 44236285Sbrian return (len); 4436059Samurai 44428679Sbrian default: 44528679Sbrian goto bad; 4466059Samurai 44728679Sbrian case TYPE_COMPRESSED_TCP: 44828679Sbrian break; 44928679Sbrian } 45028679Sbrian /* We've got a compressed packet. */ 45136285Sbrian slstat->sls_compressedin++; 45236285Sbrian cp = *bufp; 45328679Sbrian changes = *cp++; 45436285Sbrian log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 45528679Sbrian if (changes & NEW_C) { 4566059Samurai 45728679Sbrian /* 45828679Sbrian * Make sure the state index is in range, then grab the state. If we have 45928679Sbrian * a good state index, clear the 'discard' flag. 46028679Sbrian */ 46136960Sbrian if (*cp > max_state || comp->last_recv == 255) { 46228679Sbrian goto bad; 46336960Sbrian } 4646059Samurai 46528679Sbrian comp->flags &= ~SLF_TOSS; 46628679Sbrian comp->last_recv = *cp++; 46728679Sbrian } else { 4686059Samurai 46928679Sbrian /* 47028679Sbrian * this packet has an implicit state index. If we've had a line error 47128679Sbrian * since the last time we got an explicit state index, we have to toss 47228679Sbrian * the packet. 47328679Sbrian */ 47428679Sbrian if (comp->flags & SLF_TOSS) { 47536285Sbrian slstat->sls_tossed++; 47636285Sbrian return (0); 47728679Sbrian } 47828679Sbrian } 47928679Sbrian cs = &comp->rstate[comp->last_recv]; 48028679Sbrian hlen = cs->cs_ip.ip_hl << 2; 48136960Sbrian if (hlen == 0) 48236960Sbrian goto bad; /* We've been pointed at a not-yet-used slot ! */ 48328679Sbrian th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 48428679Sbrian th->th_sum = htons((*cp << 8) | cp[1]); 48528679Sbrian cp += 2; 48628679Sbrian if (changes & TCP_PUSH_BIT) 48728679Sbrian th->th_flags |= TH_PUSH; 48828679Sbrian else 48928679Sbrian th->th_flags &= ~TH_PUSH; 49028679Sbrian 49128679Sbrian switch (changes & SPECIALS_MASK) { 49228679Sbrian case SPECIAL_I: 49328679Sbrian { 49428679Sbrian register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 49528679Sbrian 49628679Sbrian th->th_ack = htonl(ntohl(th->th_ack) + i); 49728679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + i); 49828679Sbrian } 49928679Sbrian break; 50028679Sbrian 50128679Sbrian case SPECIAL_D: 50228679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 50328679Sbrian - cs->cs_hlen); 50428679Sbrian break; 50528679Sbrian 50628679Sbrian default: 50728679Sbrian if (changes & NEW_U) { 50828679Sbrian th->th_flags |= TH_URG; 50928679Sbrian DECODEU(th->th_urp) 51028679Sbrian } else 51128679Sbrian th->th_flags &= ~TH_URG; 51228679Sbrian if (changes & NEW_W) 51328679Sbrian DECODES(th->th_win) 51428679Sbrian if (changes & NEW_A) 51528679Sbrian DECODEL(th->th_ack) 51628679Sbrian if (changes & NEW_S) { 51736285Sbrian log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 51828679Sbrian *cp, cp[1], cp[2]); 51928679Sbrian DECODEL(th->th_seq) 5206059Samurai } 52128679Sbrian break; 52228679Sbrian } 52328679Sbrian if (changes & NEW_I) { 52428679Sbrian DECODES(cs->cs_ip.ip_id) 52528679Sbrian } else 52628679Sbrian cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 5276059Samurai 52836285Sbrian log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 52936285Sbrian cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 53026516Sbrian 53128679Sbrian /* 53228679Sbrian * At this point, cp points to the first byte of data in the packet. If 53328679Sbrian * we're not aligned on a 4-byte boundary, copy the data down so the ip & 53428679Sbrian * tcp headers will be aligned. Then back up cp by the tcp/ip header 53528679Sbrian * length to make room for the reconstructed header (we assume the packet 53628679Sbrian * we were handed has enough space to prepend 128 bytes of header). Adjust 53728679Sbrian * the length to account for the new header & fill in the IP total length. 53828679Sbrian */ 53928679Sbrian len -= (cp - *bufp); 54028679Sbrian if (len < 0) 5416059Samurai 54228679Sbrian /* 54328679Sbrian * we must have dropped some characters (crc should detect this but the 54428679Sbrian * old slip framing won't) 54528679Sbrian */ 54628679Sbrian goto bad; 54728679Sbrian 5486059Samurai#ifdef notdef 54928679Sbrian if ((int) cp & 3) { 55028679Sbrian if (len > 0) 55130715Sbrian (void) bcopy(cp, (caddr_t) ((int) cp & ~3), len); 55228679Sbrian cp = (u_char *) ((int) cp & ~3); 55328679Sbrian } 5546059Samurai#endif 5556059Samurai 55628679Sbrian cp -= cs->cs_hlen; 55728679Sbrian len += cs->cs_hlen; 55828679Sbrian cs->cs_ip.ip_len = htons(len); 55930715Sbrian memcpy(cp, &cs->cs_ip, cs->cs_hlen); 56028679Sbrian *bufp = cp; 5616059Samurai 56228679Sbrian /* recompute the ip header checksum */ 56328679Sbrian { 56428679Sbrian register u_short *bp = (u_short *) cp; 56528679Sbrian 56628679Sbrian for (changes = 0; hlen > 0; hlen -= 2) 56728679Sbrian changes += *bp++; 56828679Sbrian changes = (changes & 0xffff) + (changes >> 16); 56928679Sbrian changes = (changes & 0xffff) + (changes >> 16); 57028679Sbrian ((struct ip *) cp)->ip_sum = ~changes; 57128679Sbrian } 57228679Sbrian return (len); 5736059Samuraibad: 57428679Sbrian comp->flags |= SLF_TOSS; 57536285Sbrian slstat->sls_errorin++; 57636285Sbrian return (0); 5776059Samurai} 5786059Samurai 5796059Samuraiint 58036285Sbriansl_Show(struct cmdargs const *arg) 5816059Samurai{ 58236285Sbrian prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 58336285Sbrian prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 58436285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 58536285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 58636285Sbrian prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 58736285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 58836285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 58936285Sbrian prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 59036285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 59136285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 59236285Sbrian prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 59336285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 59436285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 59526516Sbrian return 0; 5966059Samurai} 597