slcompress.c revision 98243
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 * 2050479Speter * $FreeBSD: head/usr.sbin/ppp/slcompress.c 98243 2002-06-15 08:03:30Z brian $ 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> 3181634Sbrian#include <sys/socket.h> 3236285Sbrian#include <sys/un.h> 3330715Sbrian 3430715Sbrian#include <stdio.h> 3530715Sbrian#include <string.h> 3636285Sbrian#include <termios.h> 3730715Sbrian 3846686Sbrian#include "layer.h" 3937009Sbrian#include "defs.h" 4031343Sbrian#include "command.h" 4130715Sbrian#include "mbuf.h" 4230715Sbrian#include "log.h" 436059Samurai#include "slcompress.h" 4436285Sbrian#include "descriptor.h" 4536285Sbrian#include "prompt.h" 4636285Sbrian#include "timer.h" 4736285Sbrian#include "fsm.h" 4836285Sbrian#include "throughput.h" 4936285Sbrian#include "iplist.h" 5038557Sbrian#include "lqr.h" 5138557Sbrian#include "hdlc.h" 5281634Sbrian#include "ncpaddr.h" 5336285Sbrian#include "ipcp.h" 5436285Sbrian#include "filter.h" 5536285Sbrian#include "lcp.h" 5636285Sbrian#include "ccp.h" 5736285Sbrian#include "link.h" 5836285Sbrian#include "mp.h" 5943313Sbrian#ifndef NORADIUS 6043313Sbrian#include "radius.h" 6143313Sbrian#endif 6281634Sbrian#include "ipv6cp.h" 6381634Sbrian#include "ncp.h" 6436285Sbrian#include "bundle.h" 656059Samurai 666059Samuraivoid 6746828Sbriansl_compress_init(struct slcompress *comp, int max_state) 686059Samurai{ 6928679Sbrian register u_int i; 7028679Sbrian register struct cstate *tstate = comp->tstate; 716059Samurai 7231962Sbrian memset(comp, '\0', sizeof *comp); 7330187Sbrian for (i = max_state; i > 0; --i) { 7428679Sbrian tstate[i].cs_id = i; 7528679Sbrian tstate[i].cs_next = &tstate[i - 1]; 7628679Sbrian } 7730187Sbrian tstate[0].cs_next = &tstate[max_state]; 7828679Sbrian tstate[0].cs_id = 0; 7928679Sbrian comp->last_cs = &tstate[0]; 8028679Sbrian comp->last_recv = 255; 8128679Sbrian comp->last_xmit = 255; 8228679Sbrian comp->flags = SLF_TOSS; 836059Samurai} 846059Samurai 856059Samurai 866059Samurai/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 8737189Sbrian * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 886059Samurai * form). 896059Samurai */ 906059Samurai#define ENCODE(n) { \ 916059Samurai if ((u_short)(n) >= 256) { \ 926059Samurai *cp++ = 0; \ 936059Samurai cp[1] = (n); \ 946059Samurai cp[0] = (n) >> 8; \ 956059Samurai cp += 2; \ 966059Samurai } else { \ 976059Samurai *cp++ = (n); \ 986059Samurai } \ 996059Samurai} 1006059Samurai#define ENCODEZ(n) { \ 1016059Samurai if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 1026059Samurai *cp++ = 0; \ 1036059Samurai cp[1] = (n); \ 1046059Samurai cp[0] = (n) >> 8; \ 1056059Samurai cp += 2; \ 1066059Samurai } else { \ 1076059Samurai *cp++ = (n); \ 1086059Samurai } \ 1096059Samurai} 1106059Samurai 1116059Samurai#define DECODEL(f) { \ 1126059Samurai if (*cp == 0) {\ 1136059Samurai (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 1146059Samurai cp += 3; \ 1156059Samurai } else { \ 11637189Sbrian (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 1176059Samurai } \ 1186059Samurai} 1196059Samurai 1206059Samurai#define DECODES(f) { \ 1216059Samurai if (*cp == 0) {\ 1226059Samurai (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 1236059Samurai cp += 3; \ 1246059Samurai } else { \ 12537189Sbrian (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 1266059Samurai } \ 1276059Samurai} 1286059Samurai 1296059Samurai#define DECODEU(f) { \ 1306059Samurai if (*cp == 0) {\ 1316059Samurai (f) = htons((cp[1] << 8) | cp[2]); \ 1326059Samurai cp += 3; \ 1336059Samurai } else { \ 13437189Sbrian (f) = htons((u_int32_t)*cp++); \ 1356059Samurai } \ 1366059Samurai} 1376059Samurai 1386059Samurai 1396059Samuraiu_char 14028679Sbriansl_compress_tcp(struct mbuf * m, 14128679Sbrian struct ip * ip, 14236285Sbrian struct slcompress *comp, 14336285Sbrian struct slstat *slstat, 14428679Sbrian int compress_cid) 1456059Samurai{ 14628679Sbrian register struct cstate *cs = comp->last_cs->cs_next; 14728679Sbrian register u_int hlen = ip->ip_hl; 14828679Sbrian register struct tcphdr *oth; 14928679Sbrian register struct tcphdr *th; 15028679Sbrian register u_int deltaS, deltaA; 15128679Sbrian register u_int changes = 0; 15228679Sbrian u_char new_seq[16]; 15328679Sbrian register u_char *cp = new_seq; 1546059Samurai 15528679Sbrian /* 15628679Sbrian * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 15728679Sbrian * (i.e., ACK isn't set or some other control bit is set). (We assume that 15828679Sbrian * the caller has already made sure the packet is IP proto TCP). 15928679Sbrian */ 16054912Sbrian if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) { 16158042Sbrian log_Printf(LogDEBUG, "??? 1 ip_off = %x, m_len = %lu\n", 16258042Sbrian ip->ip_off, (unsigned long)m->m_len); 16336285Sbrian log_DumpBp(LogDEBUG, "", m); 16428679Sbrian return (TYPE_IP); 16528679Sbrian } 16628679Sbrian th = (struct tcphdr *) & ((int *) ip)[hlen]; 16728679Sbrian if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16836285Sbrian log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 16936285Sbrian log_DumpBp(LogDEBUG, "", m); 17028679Sbrian return (TYPE_IP); 17128679Sbrian } 1726059Samurai 17328679Sbrian /* 17428679Sbrian * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 17528679Sbrian * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 17628679Sbrian * connection state. Special case the most recently used connection since 17728679Sbrian * it's most likely to be used again & we don't have to do any reordering 17828679Sbrian * if it's used. 17928679Sbrian */ 18036285Sbrian slstat->sls_packets++; 18136285Sbrian if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 18236285Sbrian ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 18336285Sbrian *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 1846059Samurai 18528679Sbrian /* 18628679Sbrian * Wasn't the first -- search for it. 18798243Sbrian * 18828679Sbrian * States are kept in a circularly linked list with last_cs pointing to the 18928679Sbrian * end of the list. The list is kept in lru order by moving a state to 19028679Sbrian * the head of the list whenever it is referenced. Since the list is 19128679Sbrian * short and, empirically, the connection we want is almost always near 19228679Sbrian * the front, we locate states via linear search. If we don't find a 19328679Sbrian * state for the datagram, the oldest state is (re-)used. 19428679Sbrian */ 19528679Sbrian register struct cstate *lcs; 19628679Sbrian register struct cstate *lastcs = comp->last_cs; 1976059Samurai 19828679Sbrian do { 19928679Sbrian lcs = cs; 20028679Sbrian cs = cs->cs_next; 20136285Sbrian slstat->sls_searches++; 20236285Sbrian if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 20336285Sbrian && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 20436285Sbrian && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 20528679Sbrian goto found; 20628679Sbrian } while (cs != lastcs); 2076059Samurai 20828679Sbrian /* 20928679Sbrian * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 21028679Sbrian * that tells the other side what connection number we're using for this 21128679Sbrian * conversation. Note that since the state list is circular, the oldest 21228679Sbrian * state points to the newest and we only need to set last_cs to update 21328679Sbrian * the lru linkage. 21428679Sbrian */ 21536285Sbrian slstat->sls_misses++; 21628679Sbrian comp->last_cs = lcs; 2176059Samurai#define THOFFSET(th) (th->th_off) 21828679Sbrian hlen += th->th_off; 21928679Sbrian hlen <<= 2; 22054912Sbrian if (hlen > m->m_len) 22128679Sbrian return (TYPE_IP); 22228679Sbrian goto uncompressed; 2236059Samurai 22428679Sbrianfound: 2256059Samurai 22628679Sbrian /* 22728679Sbrian * Found it -- move to the front on the connection list. 22828679Sbrian */ 22928679Sbrian if (cs == lastcs) 23028679Sbrian comp->last_cs = lcs; 23128679Sbrian else { 23228679Sbrian lcs->cs_next = cs->cs_next; 23328679Sbrian cs->cs_next = lastcs->cs_next; 23428679Sbrian lastcs->cs_next = cs; 23528679Sbrian } 23628679Sbrian } 2376059Samurai 23828679Sbrian /* 23928679Sbrian * Make sure that only what we expect to change changed. The first line of 24028679Sbrian * the `if' checks the IP protocol version, header length & type of 24128679Sbrian * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 24228679Sbrian * checks the time-to-live and protocol (the protocol check is unnecessary 24328679Sbrian * but costless). The 4th line checks the TCP header length. The 5th line 24428679Sbrian * checks IP options, if any. The 6th line checks TCP options, if any. If 24528679Sbrian * any of these things are different between the previous & current 24628679Sbrian * datagram, we send the current datagram `uncompressed'. 24728679Sbrian */ 24828679Sbrian oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 24928679Sbrian deltaS = hlen; 25028679Sbrian hlen += th->th_off; 25128679Sbrian hlen <<= 2; 25254912Sbrian if (hlen > m->m_len) 25328679Sbrian return (TYPE_IP); 2546059Samurai 25528679Sbrian if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 25628679Sbrian ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 25728679Sbrian ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 25828679Sbrian THOFFSET(th) != THOFFSET(oth) || 25928679Sbrian (deltaS > 5 && 26030715Sbrian memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 26128679Sbrian (THOFFSET(th) > 5 && 26230715Sbrian memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 26328679Sbrian goto uncompressed; 26428679Sbrian } 2656059Samurai 26628679Sbrian /* 26728679Sbrian * Figure out which of the changing fields changed. The receiver expects 26828679Sbrian * changes in the order: urgent, window, ack, seq (the order minimizes the 26928679Sbrian * number of temporaries needed in this section of code). 27028679Sbrian */ 27128679Sbrian if (th->th_flags & TH_URG) { 27228679Sbrian deltaS = ntohs(th->th_urp); 27328679Sbrian ENCODEZ(deltaS); 27428679Sbrian changes |= NEW_U; 27528679Sbrian } else if (th->th_urp != oth->th_urp) { 2766059Samurai 27728679Sbrian /* 27828679Sbrian * argh! URG not set but urp changed -- a sensible implementation should 27928679Sbrian * never do this but RFC793 doesn't prohibit the change so we have to 28028679Sbrian * deal with it. 28128679Sbrian */ 28228679Sbrian goto uncompressed; 28328679Sbrian } 28428679Sbrian deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 28528679Sbrian if (deltaS) { 28628679Sbrian ENCODE(deltaS); 28728679Sbrian changes |= NEW_W; 28828679Sbrian } 28928679Sbrian deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 29028679Sbrian if (deltaA) { 29128679Sbrian if (deltaA > 0xffff) { 29228679Sbrian goto uncompressed; 29328679Sbrian } 29428679Sbrian ENCODE(deltaA); 29528679Sbrian changes |= NEW_A; 29628679Sbrian } 29728679Sbrian deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29828679Sbrian if (deltaS) { 29928679Sbrian if (deltaS > 0xffff) { 30028679Sbrian goto uncompressed; 30128679Sbrian } 30228679Sbrian ENCODE(deltaS); 30328679Sbrian changes |= NEW_S; 30428679Sbrian } 30528679Sbrian switch (changes) { 3066059Samurai 30728679Sbrian case 0: 3086059Samurai 30928679Sbrian /* 31028679Sbrian * Nothing changed. If this packet contains data and the last one didn't, 31128679Sbrian * this is probably a data packet following an ack (normal on an 31228679Sbrian * interactive connection) and we send it compressed. Otherwise it's 31328679Sbrian * probably a retransmit, retransmitted ack or window probe. Send it 31428679Sbrian * uncompressed in case the other side missed the compressed version. 31528679Sbrian */ 31628679Sbrian if (ip->ip_len != cs->cs_ip.ip_len && 31728679Sbrian ntohs(cs->cs_ip.ip_len) == hlen) 31828679Sbrian break; 3196059Samurai 32028679Sbrian /* (fall through) */ 3216059Samurai 32228679Sbrian case SPECIAL_I: 32328679Sbrian case SPECIAL_D: 3246059Samurai 32528679Sbrian /* 32628679Sbrian * actual changes match one of our special case encodings -- send packet 32728679Sbrian * uncompressed. 32828679Sbrian */ 32928679Sbrian goto uncompressed; 3306059Samurai 33128679Sbrian case NEW_S | NEW_A: 33228679Sbrian if (deltaS == deltaA && 33328679Sbrian deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33428679Sbrian /* special case for echoed terminal traffic */ 33528679Sbrian changes = SPECIAL_I; 33628679Sbrian cp = new_seq; 33728679Sbrian } 33828679Sbrian break; 3396059Samurai 34028679Sbrian case NEW_S: 34128679Sbrian if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 34228679Sbrian /* special case for data xfer */ 34328679Sbrian changes = SPECIAL_D; 34428679Sbrian cp = new_seq; 34528679Sbrian } 34628679Sbrian break; 34728679Sbrian } 3486059Samurai 34928679Sbrian deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 35028679Sbrian if (deltaS != 1) { 35128679Sbrian ENCODEZ(deltaS); 35228679Sbrian changes |= NEW_I; 35328679Sbrian } 35428679Sbrian if (th->th_flags & TH_PUSH) 35528679Sbrian changes |= TCP_PUSH_BIT; 3566059Samurai 35728679Sbrian /* 35828679Sbrian * Grab the cksum before we overwrite it below. Then update our state with 35928679Sbrian * this packet's header. 36028679Sbrian */ 36128679Sbrian deltaA = ntohs(th->th_sum); 36230715Sbrian memcpy(&cs->cs_ip, ip, hlen); 3636059Samurai 36428679Sbrian /* 36528679Sbrian * We want to use the original packet as our compressed packet. (cp - 36628679Sbrian * new_seq) is the number of bytes we need for compressed sequence numbers. 36728679Sbrian * In addition we need one byte for the change mask, one for the connection 36828679Sbrian * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 36928679Sbrian * are needed. hlen is how many bytes of the original packet to toss so 37028679Sbrian * subtract the two to get the new packet size. 37128679Sbrian */ 37228679Sbrian deltaS = cp - new_seq; 37328679Sbrian cp = (u_char *) ip; 37428679Sbrian 37528679Sbrian /* 37628679Sbrian * Since fastq traffic can jump ahead of the background traffic, we don't 37728679Sbrian * know what order packets will go on the line. In this case, we always 37828679Sbrian * send a "new" connection id so the receiver state stays synchronized. 37928679Sbrian */ 38030187Sbrian if (comp->last_xmit == cs->cs_id && compress_cid) { 38128679Sbrian hlen -= deltaS + 3; 38228679Sbrian cp += hlen; 38328679Sbrian *cp++ = changes; 38430187Sbrian } else { 38528679Sbrian comp->last_xmit = cs->cs_id; 38628679Sbrian hlen -= deltaS + 4; 38728679Sbrian cp += hlen; 38828679Sbrian *cp++ = changes | NEW_C; 38928679Sbrian *cp++ = cs->cs_id; 39028679Sbrian } 39154912Sbrian m->m_len -= hlen; 39254912Sbrian m->m_offset += hlen; 39328679Sbrian *cp++ = deltaA >> 8; 39428679Sbrian *cp++ = deltaA; 39530715Sbrian memcpy(cp, new_seq, deltaS); 39636285Sbrian slstat->sls_compressed++; 39736285Sbrian return (TYPE_COMPRESSED_TCP); 3986059Samurai 39928679Sbrian /* 40028679Sbrian * Update connection state cs & send uncompressed packet ('uncompressed' 40128679Sbrian * means a regular ip/tcp packet but with the 'conversation id' we hope to 40228679Sbrian * use on future compressed packets in the protocol field). 40328679Sbrian */ 4046059Samuraiuncompressed: 40530715Sbrian memcpy(&cs->cs_ip, ip, hlen); 40628679Sbrian ip->ip_p = cs->cs_id; 40728679Sbrian comp->last_xmit = cs->cs_id; 40828679Sbrian return (TYPE_UNCOMPRESSED_TCP); 4096059Samurai} 4106059Samurai 4116059Samurai 4126059Samuraiint 41336960Sbriansl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 41436960Sbrian struct slstat *slstat, int max_state) 4156059Samurai{ 41628679Sbrian register u_char *cp; 41728679Sbrian register u_int hlen, changes; 41828679Sbrian register struct tcphdr *th; 41928679Sbrian register struct cstate *cs; 42028679Sbrian register struct ip *ip; 42152197Sbrian u_short *bp; 4226059Samurai 42328679Sbrian switch (type) { 4246059Samurai 42528679Sbrian case TYPE_UNCOMPRESSED_TCP: 42628679Sbrian ip = (struct ip *) * bufp; 42736960Sbrian if (ip->ip_p > max_state) 42828679Sbrian goto bad; 42928679Sbrian cs = &comp->rstate[comp->last_recv = ip->ip_p]; 43028679Sbrian comp->flags &= ~SLF_TOSS; 43128679Sbrian ip->ip_p = IPPROTO_TCP; 4326059Samurai 43328679Sbrian /* 43428679Sbrian * Calculate the size of the TCP/IP header and make sure that we don't 43528679Sbrian * overflow the space we have available for it. 43628679Sbrian */ 43728679Sbrian hlen = ip->ip_hl << 2; 43828679Sbrian if (hlen + sizeof(struct tcphdr) > len) 43928679Sbrian goto bad; 44028679Sbrian th = (struct tcphdr *) & ((char *) ip)[hlen]; 44128679Sbrian hlen += THOFFSET(th) << 2; 44228679Sbrian if (hlen > MAX_HDR) 44328679Sbrian goto bad; 44430715Sbrian memcpy(&cs->cs_ip, ip, hlen); 44528679Sbrian cs->cs_hlen = hlen; 44636285Sbrian slstat->sls_uncompressedin++; 44736285Sbrian return (len); 4486059Samurai 44928679Sbrian default: 45028679Sbrian goto bad; 4516059Samurai 45228679Sbrian case TYPE_COMPRESSED_TCP: 45328679Sbrian break; 45428679Sbrian } 45545138Sbrian 45628679Sbrian /* We've got a compressed packet. */ 45736285Sbrian slstat->sls_compressedin++; 45836285Sbrian cp = *bufp; 45928679Sbrian changes = *cp++; 46036285Sbrian log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 46145138Sbrian 46228679Sbrian if (changes & NEW_C) { 46328679Sbrian /* 46428679Sbrian * Make sure the state index is in range, then grab the state. If we have 46528679Sbrian * a good state index, clear the 'discard' flag. 46628679Sbrian */ 46746686Sbrian if (*cp > max_state || comp->last_recv == 255) 46828679Sbrian goto bad; 4696059Samurai 47028679Sbrian comp->flags &= ~SLF_TOSS; 47128679Sbrian comp->last_recv = *cp++; 47228679Sbrian } else { 47328679Sbrian /* 47428679Sbrian * this packet has an implicit state index. If we've had a line error 47528679Sbrian * since the last time we got an explicit state index, we have to toss 47628679Sbrian * the packet. 47728679Sbrian */ 47828679Sbrian if (comp->flags & SLF_TOSS) { 47936285Sbrian slstat->sls_tossed++; 48036285Sbrian return (0); 48128679Sbrian } 48228679Sbrian } 48328679Sbrian cs = &comp->rstate[comp->last_recv]; 48428679Sbrian hlen = cs->cs_ip.ip_hl << 2; 48528679Sbrian th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 48628679Sbrian th->th_sum = htons((*cp << 8) | cp[1]); 48728679Sbrian cp += 2; 48828679Sbrian if (changes & TCP_PUSH_BIT) 48928679Sbrian th->th_flags |= TH_PUSH; 49028679Sbrian else 49128679Sbrian th->th_flags &= ~TH_PUSH; 49228679Sbrian 49328679Sbrian switch (changes & SPECIALS_MASK) { 49428679Sbrian case SPECIAL_I: 49528679Sbrian { 49628679Sbrian register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 49728679Sbrian 49828679Sbrian th->th_ack = htonl(ntohl(th->th_ack) + i); 49928679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + i); 50028679Sbrian } 50128679Sbrian break; 50228679Sbrian 50328679Sbrian case SPECIAL_D: 50428679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 50528679Sbrian - cs->cs_hlen); 50628679Sbrian break; 50728679Sbrian 50828679Sbrian default: 50928679Sbrian if (changes & NEW_U) { 51028679Sbrian th->th_flags |= TH_URG; 51128679Sbrian DECODEU(th->th_urp) 51228679Sbrian } else 51328679Sbrian th->th_flags &= ~TH_URG; 51428679Sbrian if (changes & NEW_W) 51528679Sbrian DECODES(th->th_win) 51628679Sbrian if (changes & NEW_A) 51728679Sbrian DECODEL(th->th_ack) 51828679Sbrian if (changes & NEW_S) { 51936285Sbrian log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 52028679Sbrian *cp, cp[1], cp[2]); 52128679Sbrian DECODEL(th->th_seq) 5226059Samurai } 52328679Sbrian break; 52428679Sbrian } 52528679Sbrian if (changes & NEW_I) { 52628679Sbrian DECODES(cs->cs_ip.ip_id) 52728679Sbrian } else 52828679Sbrian cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 5296059Samurai 53036285Sbrian log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 53136285Sbrian cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 53226516Sbrian 53328679Sbrian /* 53445138Sbrian * At this point, cp points to the first byte of data in the packet. 53545138Sbrian * Back up cp by the tcp/ip header length to make room for the 53645138Sbrian * reconstructed header (we assume the packet we were handed has enough 53745138Sbrian * space to prepend 128 bytes of header). Adjust the length to account 53845138Sbrian * for the new header & fill in the IP total length. 53928679Sbrian */ 54028679Sbrian len -= (cp - *bufp); 54128679Sbrian if (len < 0) 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 54852197Sbrian *bufp = cp - cs->cs_hlen; 54928679Sbrian len += cs->cs_hlen; 55028679Sbrian cs->cs_ip.ip_len = htons(len); 5516059Samurai 55228679Sbrian /* recompute the ip header checksum */ 55352197Sbrian cs->cs_ip.ip_sum = 0; 55452197Sbrian bp = (u_short *)&cs->cs_ip; 55552197Sbrian for (changes = 0; hlen > 0; hlen -= 2) 55652197Sbrian changes += *bp++; 55752197Sbrian changes = (changes & 0xffff) + (changes >> 16); 55852197Sbrian changes = (changes & 0xffff) + (changes >> 16); 55952197Sbrian cs->cs_ip.ip_sum = ~changes; 56028679Sbrian 56152197Sbrian /* And copy the result into our buffer */ 56252197Sbrian memcpy(*bufp, &cs->cs_ip, cs->cs_hlen); 56345185Sbrian 56428679Sbrian return (len); 5656059Samuraibad: 56628679Sbrian comp->flags |= SLF_TOSS; 56736285Sbrian slstat->sls_errorin++; 56836285Sbrian return (0); 5696059Samurai} 5706059Samurai 5716059Samuraiint 57236285Sbriansl_Show(struct cmdargs const *arg) 5736059Samurai{ 57436285Sbrian prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 57536285Sbrian prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 57636285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 57736285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 57836285Sbrian prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 57936285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 58036285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 58136285Sbrian prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 58236285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 58336285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 58436285Sbrian prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 58536285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 58636285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 58726516Sbrian return 0; 5886059Samurai} 589