slcompress.c revision 134789
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 134789 2004-09-05 01:46:52Z 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 34102500Sbrian#include <stdarg.h> 3530715Sbrian#include <stdio.h> 3630715Sbrian#include <string.h> 3736285Sbrian#include <termios.h> 3830715Sbrian 3946686Sbrian#include "layer.h" 4037009Sbrian#include "defs.h" 4131343Sbrian#include "command.h" 4230715Sbrian#include "mbuf.h" 4330715Sbrian#include "log.h" 446059Samurai#include "slcompress.h" 4536285Sbrian#include "descriptor.h" 4636285Sbrian#include "prompt.h" 4736285Sbrian#include "timer.h" 4836285Sbrian#include "fsm.h" 4936285Sbrian#include "throughput.h" 5036285Sbrian#include "iplist.h" 5138557Sbrian#include "lqr.h" 5238557Sbrian#include "hdlc.h" 5381634Sbrian#include "ncpaddr.h" 5436285Sbrian#include "ipcp.h" 5536285Sbrian#include "filter.h" 5636285Sbrian#include "lcp.h" 5736285Sbrian#include "ccp.h" 5836285Sbrian#include "link.h" 5936285Sbrian#include "mp.h" 6043313Sbrian#ifndef NORADIUS 6143313Sbrian#include "radius.h" 6243313Sbrian#endif 6381634Sbrian#include "ipv6cp.h" 6481634Sbrian#include "ncp.h" 6536285Sbrian#include "bundle.h" 666059Samurai 676059Samuraivoid 6846828Sbriansl_compress_init(struct slcompress *comp, int max_state) 696059Samurai{ 7028679Sbrian register u_int i; 7128679Sbrian register struct cstate *tstate = comp->tstate; 726059Samurai 7331962Sbrian memset(comp, '\0', sizeof *comp); 7430187Sbrian for (i = max_state; i > 0; --i) { 7528679Sbrian tstate[i].cs_id = i; 7628679Sbrian tstate[i].cs_next = &tstate[i - 1]; 7728679Sbrian } 7830187Sbrian tstate[0].cs_next = &tstate[max_state]; 7928679Sbrian tstate[0].cs_id = 0; 8028679Sbrian comp->last_cs = &tstate[0]; 8128679Sbrian comp->last_recv = 255; 8228679Sbrian comp->last_xmit = 255; 8328679Sbrian comp->flags = SLF_TOSS; 846059Samurai} 856059Samurai 866059Samurai 876059Samurai/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 8837189Sbrian * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 896059Samurai * form). 906059Samurai */ 916059Samurai#define ENCODE(n) { \ 926059Samurai if ((u_short)(n) >= 256) { \ 936059Samurai *cp++ = 0; \ 946059Samurai cp[1] = (n); \ 956059Samurai cp[0] = (n) >> 8; \ 966059Samurai cp += 2; \ 976059Samurai } else { \ 986059Samurai *cp++ = (n); \ 996059Samurai } \ 1006059Samurai} 1016059Samurai#define ENCODEZ(n) { \ 1026059Samurai if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 1036059Samurai *cp++ = 0; \ 1046059Samurai cp[1] = (n); \ 1056059Samurai cp[0] = (n) >> 8; \ 1066059Samurai cp += 2; \ 1076059Samurai } else { \ 1086059Samurai *cp++ = (n); \ 1096059Samurai } \ 1106059Samurai} 1116059Samurai 1126059Samurai#define DECODEL(f) { \ 1136059Samurai if (*cp == 0) {\ 1146059Samurai (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 1156059Samurai cp += 3; \ 1166059Samurai } else { \ 11737189Sbrian (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 1186059Samurai } \ 1196059Samurai} 1206059Samurai 1216059Samurai#define DECODES(f) { \ 1226059Samurai if (*cp == 0) {\ 1236059Samurai (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 1246059Samurai cp += 3; \ 1256059Samurai } else { \ 12637189Sbrian (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 1276059Samurai } \ 1286059Samurai} 1296059Samurai 1306059Samurai#define DECODEU(f) { \ 1316059Samurai if (*cp == 0) {\ 1326059Samurai (f) = htons((cp[1] << 8) | cp[2]); \ 1336059Samurai cp += 3; \ 1346059Samurai } else { \ 13537189Sbrian (f) = htons((u_int32_t)*cp++); \ 1366059Samurai } \ 1376059Samurai} 1386059Samurai 1396059Samurai 1406059Samuraiu_char 14128679Sbriansl_compress_tcp(struct mbuf * m, 14228679Sbrian struct ip * ip, 14336285Sbrian struct slcompress *comp, 14436285Sbrian struct slstat *slstat, 14528679Sbrian int compress_cid) 1466059Samurai{ 14728679Sbrian register struct cstate *cs = comp->last_cs->cs_next; 14828679Sbrian register u_int hlen = ip->ip_hl; 14928679Sbrian register struct tcphdr *oth; 15028679Sbrian register struct tcphdr *th; 15128679Sbrian register u_int deltaS, deltaA; 15228679Sbrian register u_int changes = 0; 15328679Sbrian u_char new_seq[16]; 15428679Sbrian register u_char *cp = new_seq; 1556059Samurai 15628679Sbrian /* 15728679Sbrian * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 15828679Sbrian * (i.e., ACK isn't set or some other control bit is set). (We assume that 15928679Sbrian * the caller has already made sure the packet is IP proto TCP). 16028679Sbrian */ 16154912Sbrian if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) { 16258042Sbrian log_Printf(LogDEBUG, "??? 1 ip_off = %x, m_len = %lu\n", 16358042Sbrian ip->ip_off, (unsigned long)m->m_len); 16436285Sbrian log_DumpBp(LogDEBUG, "", m); 16528679Sbrian return (TYPE_IP); 16628679Sbrian } 16728679Sbrian th = (struct tcphdr *) & ((int *) ip)[hlen]; 16828679Sbrian if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16936285Sbrian log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 17036285Sbrian log_DumpBp(LogDEBUG, "", m); 17128679Sbrian return (TYPE_IP); 17228679Sbrian } 1736059Samurai 17428679Sbrian /* 17528679Sbrian * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 17628679Sbrian * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 17728679Sbrian * connection state. Special case the most recently used connection since 17828679Sbrian * it's most likely to be used again & we don't have to do any reordering 17928679Sbrian * if it's used. 18028679Sbrian */ 18136285Sbrian slstat->sls_packets++; 18236285Sbrian if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 18336285Sbrian ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 18436285Sbrian *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 1856059Samurai 18628679Sbrian /* 18728679Sbrian * Wasn't the first -- search for it. 18898243Sbrian * 18928679Sbrian * States are kept in a circularly linked list with last_cs pointing to the 19028679Sbrian * end of the list. The list is kept in lru order by moving a state to 19128679Sbrian * the head of the list whenever it is referenced. Since the list is 19228679Sbrian * short and, empirically, the connection we want is almost always near 19328679Sbrian * the front, we locate states via linear search. If we don't find a 19428679Sbrian * state for the datagram, the oldest state is (re-)used. 19528679Sbrian */ 19628679Sbrian register struct cstate *lcs; 19728679Sbrian register struct cstate *lastcs = comp->last_cs; 1986059Samurai 19928679Sbrian do { 20028679Sbrian lcs = cs; 20128679Sbrian cs = cs->cs_next; 20236285Sbrian slstat->sls_searches++; 20336285Sbrian if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 20436285Sbrian && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 20536285Sbrian && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 20628679Sbrian goto found; 20728679Sbrian } while (cs != lastcs); 2086059Samurai 20928679Sbrian /* 21028679Sbrian * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 21128679Sbrian * that tells the other side what connection number we're using for this 21228679Sbrian * conversation. Note that since the state list is circular, the oldest 21328679Sbrian * state points to the newest and we only need to set last_cs to update 21428679Sbrian * the lru linkage. 21528679Sbrian */ 21636285Sbrian slstat->sls_misses++; 21728679Sbrian comp->last_cs = lcs; 2186059Samurai#define THOFFSET(th) (th->th_off) 21928679Sbrian hlen += th->th_off; 22028679Sbrian hlen <<= 2; 22154912Sbrian if (hlen > m->m_len) 22228679Sbrian return (TYPE_IP); 22328679Sbrian goto uncompressed; 2246059Samurai 22528679Sbrianfound: 2266059Samurai 22728679Sbrian /* 22828679Sbrian * Found it -- move to the front on the connection list. 22928679Sbrian */ 23028679Sbrian if (cs == lastcs) 23128679Sbrian comp->last_cs = lcs; 23228679Sbrian else { 23328679Sbrian lcs->cs_next = cs->cs_next; 23428679Sbrian cs->cs_next = lastcs->cs_next; 23528679Sbrian lastcs->cs_next = cs; 23628679Sbrian } 23728679Sbrian } 2386059Samurai 23928679Sbrian /* 24028679Sbrian * Make sure that only what we expect to change changed. The first line of 24128679Sbrian * the `if' checks the IP protocol version, header length & type of 24228679Sbrian * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 24328679Sbrian * checks the time-to-live and protocol (the protocol check is unnecessary 24428679Sbrian * but costless). The 4th line checks the TCP header length. The 5th line 24528679Sbrian * checks IP options, if any. The 6th line checks TCP options, if any. If 24628679Sbrian * any of these things are different between the previous & current 24728679Sbrian * datagram, we send the current datagram `uncompressed'. 24828679Sbrian */ 24928679Sbrian oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 25028679Sbrian deltaS = hlen; 25128679Sbrian hlen += th->th_off; 25228679Sbrian hlen <<= 2; 25354912Sbrian if (hlen > m->m_len) 25428679Sbrian return (TYPE_IP); 2556059Samurai 25628679Sbrian if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 25728679Sbrian ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 25828679Sbrian ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 25928679Sbrian THOFFSET(th) != THOFFSET(oth) || 26028679Sbrian (deltaS > 5 && 26130715Sbrian memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 26228679Sbrian (THOFFSET(th) > 5 && 26330715Sbrian memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 26428679Sbrian goto uncompressed; 26528679Sbrian } 2666059Samurai 26728679Sbrian /* 26828679Sbrian * Figure out which of the changing fields changed. The receiver expects 26928679Sbrian * changes in the order: urgent, window, ack, seq (the order minimizes the 27028679Sbrian * number of temporaries needed in this section of code). 27128679Sbrian */ 27228679Sbrian if (th->th_flags & TH_URG) { 27328679Sbrian deltaS = ntohs(th->th_urp); 27428679Sbrian ENCODEZ(deltaS); 27528679Sbrian changes |= NEW_U; 27628679Sbrian } else if (th->th_urp != oth->th_urp) { 2776059Samurai 27828679Sbrian /* 27928679Sbrian * argh! URG not set but urp changed -- a sensible implementation should 28028679Sbrian * never do this but RFC793 doesn't prohibit the change so we have to 28128679Sbrian * deal with it. 28228679Sbrian */ 28328679Sbrian goto uncompressed; 28428679Sbrian } 28528679Sbrian deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 28628679Sbrian if (deltaS) { 28728679Sbrian ENCODE(deltaS); 28828679Sbrian changes |= NEW_W; 28928679Sbrian } 29028679Sbrian deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 29128679Sbrian if (deltaA) { 29228679Sbrian if (deltaA > 0xffff) { 29328679Sbrian goto uncompressed; 29428679Sbrian } 29528679Sbrian ENCODE(deltaA); 29628679Sbrian changes |= NEW_A; 29728679Sbrian } 29828679Sbrian deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29928679Sbrian if (deltaS) { 30028679Sbrian if (deltaS > 0xffff) { 30128679Sbrian goto uncompressed; 30228679Sbrian } 30328679Sbrian ENCODE(deltaS); 30428679Sbrian changes |= NEW_S; 30528679Sbrian } 30628679Sbrian switch (changes) { 3076059Samurai 30828679Sbrian case 0: 3096059Samurai 31028679Sbrian /* 31128679Sbrian * Nothing changed. If this packet contains data and the last one didn't, 31228679Sbrian * this is probably a data packet following an ack (normal on an 31328679Sbrian * interactive connection) and we send it compressed. Otherwise it's 31428679Sbrian * probably a retransmit, retransmitted ack or window probe. Send it 31528679Sbrian * uncompressed in case the other side missed the compressed version. 31628679Sbrian */ 31728679Sbrian if (ip->ip_len != cs->cs_ip.ip_len && 31828679Sbrian ntohs(cs->cs_ip.ip_len) == hlen) 31928679Sbrian break; 3206059Samurai 321102413Scharnier /* FALLTHROUGH */ 3226059Samurai 32328679Sbrian case SPECIAL_I: 32428679Sbrian case SPECIAL_D: 3256059Samurai 32628679Sbrian /* 32728679Sbrian * actual changes match one of our special case encodings -- send packet 32828679Sbrian * uncompressed. 32928679Sbrian */ 33028679Sbrian goto uncompressed; 3316059Samurai 33228679Sbrian case NEW_S | NEW_A: 33328679Sbrian if (deltaS == deltaA && 33428679Sbrian deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33528679Sbrian /* special case for echoed terminal traffic */ 33628679Sbrian changes = SPECIAL_I; 33728679Sbrian cp = new_seq; 33828679Sbrian } 33928679Sbrian break; 3406059Samurai 34128679Sbrian case NEW_S: 34228679Sbrian if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 34328679Sbrian /* special case for data xfer */ 34428679Sbrian changes = SPECIAL_D; 34528679Sbrian cp = new_seq; 34628679Sbrian } 34728679Sbrian break; 34828679Sbrian } 3496059Samurai 35028679Sbrian deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 35128679Sbrian if (deltaS != 1) { 35228679Sbrian ENCODEZ(deltaS); 35328679Sbrian changes |= NEW_I; 35428679Sbrian } 35528679Sbrian if (th->th_flags & TH_PUSH) 35628679Sbrian changes |= TCP_PUSH_BIT; 3576059Samurai 35828679Sbrian /* 35928679Sbrian * Grab the cksum before we overwrite it below. Then update our state with 36028679Sbrian * this packet's header. 36128679Sbrian */ 36228679Sbrian deltaA = ntohs(th->th_sum); 36330715Sbrian memcpy(&cs->cs_ip, ip, hlen); 3646059Samurai 36528679Sbrian /* 36628679Sbrian * We want to use the original packet as our compressed packet. (cp - 36728679Sbrian * new_seq) is the number of bytes we need for compressed sequence numbers. 36828679Sbrian * In addition we need one byte for the change mask, one for the connection 36928679Sbrian * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 37028679Sbrian * are needed. hlen is how many bytes of the original packet to toss so 37128679Sbrian * subtract the two to get the new packet size. 37228679Sbrian */ 37328679Sbrian deltaS = cp - new_seq; 37428679Sbrian cp = (u_char *) ip; 37528679Sbrian 37628679Sbrian /* 37728679Sbrian * Since fastq traffic can jump ahead of the background traffic, we don't 37828679Sbrian * know what order packets will go on the line. In this case, we always 37928679Sbrian * send a "new" connection id so the receiver state stays synchronized. 38028679Sbrian */ 38130187Sbrian if (comp->last_xmit == cs->cs_id && compress_cid) { 38228679Sbrian hlen -= deltaS + 3; 38328679Sbrian cp += hlen; 38428679Sbrian *cp++ = changes; 38530187Sbrian } else { 38628679Sbrian comp->last_xmit = cs->cs_id; 38728679Sbrian hlen -= deltaS + 4; 38828679Sbrian cp += hlen; 38928679Sbrian *cp++ = changes | NEW_C; 39028679Sbrian *cp++ = cs->cs_id; 39128679Sbrian } 39254912Sbrian m->m_len -= hlen; 39354912Sbrian m->m_offset += hlen; 39428679Sbrian *cp++ = deltaA >> 8; 39528679Sbrian *cp++ = deltaA; 39630715Sbrian memcpy(cp, new_seq, deltaS); 39736285Sbrian slstat->sls_compressed++; 39836285Sbrian return (TYPE_COMPRESSED_TCP); 3996059Samurai 40028679Sbrian /* 40128679Sbrian * Update connection state cs & send uncompressed packet ('uncompressed' 40228679Sbrian * means a regular ip/tcp packet but with the 'conversation id' we hope to 40328679Sbrian * use on future compressed packets in the protocol field). 40428679Sbrian */ 4056059Samuraiuncompressed: 40630715Sbrian memcpy(&cs->cs_ip, ip, hlen); 40728679Sbrian ip->ip_p = cs->cs_id; 40828679Sbrian comp->last_xmit = cs->cs_id; 40928679Sbrian return (TYPE_UNCOMPRESSED_TCP); 4106059Samurai} 4116059Samurai 4126059Samurai 4136059Samuraiint 41436960Sbriansl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 41536960Sbrian struct slstat *slstat, int max_state) 4166059Samurai{ 41728679Sbrian register u_char *cp; 41828679Sbrian register u_int hlen, changes; 41928679Sbrian register struct tcphdr *th; 42028679Sbrian register struct cstate *cs; 42128679Sbrian register struct ip *ip; 42252197Sbrian u_short *bp; 4236059Samurai 42428679Sbrian switch (type) { 4256059Samurai 42628679Sbrian case TYPE_UNCOMPRESSED_TCP: 42728679Sbrian ip = (struct ip *) * bufp; 42836960Sbrian if (ip->ip_p > max_state) 42928679Sbrian goto bad; 43028679Sbrian cs = &comp->rstate[comp->last_recv = ip->ip_p]; 43128679Sbrian comp->flags &= ~SLF_TOSS; 43228679Sbrian ip->ip_p = IPPROTO_TCP; 4336059Samurai 43428679Sbrian /* 43528679Sbrian * Calculate the size of the TCP/IP header and make sure that we don't 43628679Sbrian * overflow the space we have available for it. 43728679Sbrian */ 43828679Sbrian hlen = ip->ip_hl << 2; 439134789Sbrian if ((int)(hlen + sizeof(struct tcphdr)) > len) 44028679Sbrian goto bad; 44128679Sbrian th = (struct tcphdr *) & ((char *) ip)[hlen]; 44228679Sbrian hlen += THOFFSET(th) << 2; 44328679Sbrian if (hlen > MAX_HDR) 44428679Sbrian goto bad; 44530715Sbrian memcpy(&cs->cs_ip, ip, hlen); 44628679Sbrian cs->cs_hlen = hlen; 44736285Sbrian slstat->sls_uncompressedin++; 44836285Sbrian return (len); 4496059Samurai 45028679Sbrian default: 45128679Sbrian goto bad; 4526059Samurai 45328679Sbrian case TYPE_COMPRESSED_TCP: 45428679Sbrian break; 45528679Sbrian } 45645138Sbrian 45728679Sbrian /* We've got a compressed packet. */ 45836285Sbrian slstat->sls_compressedin++; 45936285Sbrian cp = *bufp; 46028679Sbrian changes = *cp++; 46136285Sbrian log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 46245138Sbrian 46328679Sbrian if (changes & NEW_C) { 46428679Sbrian /* 46528679Sbrian * Make sure the state index is in range, then grab the state. If we have 46628679Sbrian * a good state index, clear the 'discard' flag. 46728679Sbrian */ 46846686Sbrian if (*cp > max_state || comp->last_recv == 255) 46928679Sbrian goto bad; 4706059Samurai 47128679Sbrian comp->flags &= ~SLF_TOSS; 47228679Sbrian comp->last_recv = *cp++; 47328679Sbrian } else { 47428679Sbrian /* 47528679Sbrian * this packet has an implicit state index. If we've had a line error 47628679Sbrian * since the last time we got an explicit state index, we have to toss 47728679Sbrian * the packet. 47828679Sbrian */ 47928679Sbrian if (comp->flags & SLF_TOSS) { 48036285Sbrian slstat->sls_tossed++; 48136285Sbrian return (0); 48228679Sbrian } 48328679Sbrian } 48428679Sbrian cs = &comp->rstate[comp->last_recv]; 48528679Sbrian hlen = cs->cs_ip.ip_hl << 2; 48628679Sbrian th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 48728679Sbrian th->th_sum = htons((*cp << 8) | cp[1]); 48828679Sbrian cp += 2; 48928679Sbrian if (changes & TCP_PUSH_BIT) 49028679Sbrian th->th_flags |= TH_PUSH; 49128679Sbrian else 49228679Sbrian th->th_flags &= ~TH_PUSH; 49328679Sbrian 49428679Sbrian switch (changes & SPECIALS_MASK) { 49528679Sbrian case SPECIAL_I: 49628679Sbrian { 49728679Sbrian register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 49828679Sbrian 49928679Sbrian th->th_ack = htonl(ntohl(th->th_ack) + i); 50028679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + i); 50128679Sbrian } 50228679Sbrian break; 50328679Sbrian 50428679Sbrian case SPECIAL_D: 50528679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 50628679Sbrian - cs->cs_hlen); 50728679Sbrian break; 50828679Sbrian 50928679Sbrian default: 51028679Sbrian if (changes & NEW_U) { 51128679Sbrian th->th_flags |= TH_URG; 51228679Sbrian DECODEU(th->th_urp) 51328679Sbrian } else 51428679Sbrian th->th_flags &= ~TH_URG; 51528679Sbrian if (changes & NEW_W) 51628679Sbrian DECODES(th->th_win) 51728679Sbrian if (changes & NEW_A) 51828679Sbrian DECODEL(th->th_ack) 51928679Sbrian if (changes & NEW_S) { 52036285Sbrian log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 52128679Sbrian *cp, cp[1], cp[2]); 52228679Sbrian DECODEL(th->th_seq) 5236059Samurai } 52428679Sbrian break; 52528679Sbrian } 52628679Sbrian if (changes & NEW_I) { 52728679Sbrian DECODES(cs->cs_ip.ip_id) 52828679Sbrian } else 52928679Sbrian cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 5306059Samurai 53136285Sbrian log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 53236285Sbrian cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 53326516Sbrian 53428679Sbrian /* 53545138Sbrian * At this point, cp points to the first byte of data in the packet. 53645138Sbrian * Back up cp by the tcp/ip header length to make room for the 53745138Sbrian * reconstructed header (we assume the packet we were handed has enough 53845138Sbrian * space to prepend 128 bytes of header). Adjust the length to account 53945138Sbrian * for the new header & fill in the IP total length. 54028679Sbrian */ 54128679Sbrian len -= (cp - *bufp); 54228679Sbrian if (len < 0) 54328679Sbrian /* 54428679Sbrian * we must have dropped some characters (crc should detect this but the 54528679Sbrian * old slip framing won't) 54628679Sbrian */ 54728679Sbrian goto bad; 54828679Sbrian 54952197Sbrian *bufp = cp - cs->cs_hlen; 55028679Sbrian len += cs->cs_hlen; 55128679Sbrian cs->cs_ip.ip_len = htons(len); 5526059Samurai 55328679Sbrian /* recompute the ip header checksum */ 55452197Sbrian cs->cs_ip.ip_sum = 0; 55552197Sbrian bp = (u_short *)&cs->cs_ip; 55652197Sbrian for (changes = 0; hlen > 0; hlen -= 2) 55752197Sbrian changes += *bp++; 55852197Sbrian changes = (changes & 0xffff) + (changes >> 16); 55952197Sbrian changes = (changes & 0xffff) + (changes >> 16); 56052197Sbrian cs->cs_ip.ip_sum = ~changes; 56128679Sbrian 56252197Sbrian /* And copy the result into our buffer */ 56352197Sbrian memcpy(*bufp, &cs->cs_ip, cs->cs_hlen); 56445185Sbrian 56528679Sbrian return (len); 5666059Samuraibad: 56728679Sbrian comp->flags |= SLF_TOSS; 56836285Sbrian slstat->sls_errorin++; 56936285Sbrian return (0); 5706059Samurai} 5716059Samurai 5726059Samuraiint 57336285Sbriansl_Show(struct cmdargs const *arg) 5746059Samurai{ 57536285Sbrian prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 57636285Sbrian prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 57736285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 57836285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 57936285Sbrian prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 58036285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 58136285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 58236285Sbrian prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 58336285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 58436285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 58536285Sbrian prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 58636285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 58736285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 58826516Sbrian return 0; 5896059Samurai} 590