slcompress.c revision 38557
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 * 2038557Sbrian * $Id: slcompress.c,v 1.19 1998/06/27 12:03:50 brian Exp $ 218857Srgrimes * 226059Samurai * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 236059Samurai * - Initial distribution. 246059Samurai */ 2528679Sbrian 2636285Sbrian#include <sys/types.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" 5636285Sbrian#include "bundle.h" 576059Samurai 586059Samuraivoid 5930187Sbriansl_compress_init(struct slcompress * comp, int max_state) 606059Samurai{ 6128679Sbrian register u_int i; 6228679Sbrian register struct cstate *tstate = comp->tstate; 636059Samurai 6431962Sbrian memset(comp, '\0', sizeof *comp); 6530187Sbrian for (i = max_state; i > 0; --i) { 6628679Sbrian tstate[i].cs_id = i; 6728679Sbrian tstate[i].cs_next = &tstate[i - 1]; 6828679Sbrian } 6930187Sbrian tstate[0].cs_next = &tstate[max_state]; 7028679Sbrian tstate[0].cs_id = 0; 7128679Sbrian comp->last_cs = &tstate[0]; 7228679Sbrian comp->last_recv = 255; 7328679Sbrian comp->last_xmit = 255; 7428679Sbrian comp->flags = SLF_TOSS; 756059Samurai} 766059Samurai 776059Samurai 786059Samurai/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 7937189Sbrian * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 806059Samurai * form). 816059Samurai */ 826059Samurai#define ENCODE(n) { \ 836059Samurai if ((u_short)(n) >= 256) { \ 846059Samurai *cp++ = 0; \ 856059Samurai cp[1] = (n); \ 866059Samurai cp[0] = (n) >> 8; \ 876059Samurai cp += 2; \ 886059Samurai } else { \ 896059Samurai *cp++ = (n); \ 906059Samurai } \ 916059Samurai} 926059Samurai#define ENCODEZ(n) { \ 936059Samurai if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 946059Samurai *cp++ = 0; \ 956059Samurai cp[1] = (n); \ 966059Samurai cp[0] = (n) >> 8; \ 976059Samurai cp += 2; \ 986059Samurai } else { \ 996059Samurai *cp++ = (n); \ 1006059Samurai } \ 1016059Samurai} 1026059Samurai 1036059Samurai#define DECODEL(f) { \ 1046059Samurai if (*cp == 0) {\ 1056059Samurai (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 1066059Samurai cp += 3; \ 1076059Samurai } else { \ 10837189Sbrian (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 1096059Samurai } \ 1106059Samurai} 1116059Samurai 1126059Samurai#define DECODES(f) { \ 1136059Samurai if (*cp == 0) {\ 1146059Samurai (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 1156059Samurai cp += 3; \ 1166059Samurai } else { \ 11737189Sbrian (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 1186059Samurai } \ 1196059Samurai} 1206059Samurai 1216059Samurai#define DECODEU(f) { \ 1226059Samurai if (*cp == 0) {\ 1236059Samurai (f) = htons((cp[1] << 8) | cp[2]); \ 1246059Samurai cp += 3; \ 1256059Samurai } else { \ 12637189Sbrian (f) = htons((u_int32_t)*cp++); \ 1276059Samurai } \ 1286059Samurai} 1296059Samurai 1306059Samurai 1316059Samuraiu_char 13228679Sbriansl_compress_tcp(struct mbuf * m, 13328679Sbrian struct ip * ip, 13436285Sbrian struct slcompress *comp, 13536285Sbrian struct slstat *slstat, 13628679Sbrian int compress_cid) 1376059Samurai{ 13828679Sbrian register struct cstate *cs = comp->last_cs->cs_next; 13928679Sbrian register u_int hlen = ip->ip_hl; 14028679Sbrian register struct tcphdr *oth; 14128679Sbrian register struct tcphdr *th; 14228679Sbrian register u_int deltaS, deltaA; 14328679Sbrian register u_int changes = 0; 14428679Sbrian u_char new_seq[16]; 14528679Sbrian register u_char *cp = new_seq; 1466059Samurai 14728679Sbrian /* 14828679Sbrian * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 14928679Sbrian * (i.e., ACK isn't set or some other control bit is set). (We assume that 15028679Sbrian * the caller has already made sure the packet is IP proto TCP). 15128679Sbrian */ 15228679Sbrian if ((ip->ip_off & htons(0x3fff)) || m->cnt < 40) { 15336285Sbrian log_Printf(LogDEBUG, "??? 1 ip_off = %x, cnt = %d\n", 15428679Sbrian ip->ip_off, m->cnt); 15536285Sbrian log_DumpBp(LogDEBUG, "", m); 15628679Sbrian return (TYPE_IP); 15728679Sbrian } 15828679Sbrian th = (struct tcphdr *) & ((int *) ip)[hlen]; 15928679Sbrian if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16036285Sbrian log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 16136285Sbrian log_DumpBp(LogDEBUG, "", m); 16228679Sbrian return (TYPE_IP); 16328679Sbrian } 1646059Samurai 16528679Sbrian /* 16628679Sbrian * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 16728679Sbrian * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 16828679Sbrian * connection state. Special case the most recently used connection since 16928679Sbrian * it's most likely to be used again & we don't have to do any reordering 17028679Sbrian * if it's used. 17128679Sbrian */ 17236285Sbrian slstat->sls_packets++; 17336285Sbrian if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 17436285Sbrian ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 17536285Sbrian *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 1766059Samurai 17728679Sbrian /* 17828679Sbrian * Wasn't the first -- search for it. 17928679Sbrian * 18028679Sbrian * States are kept in a circularly linked list with last_cs pointing to the 18128679Sbrian * end of the list. The list is kept in lru order by moving a state to 18228679Sbrian * the head of the list whenever it is referenced. Since the list is 18328679Sbrian * short and, empirically, the connection we want is almost always near 18428679Sbrian * the front, we locate states via linear search. If we don't find a 18528679Sbrian * state for the datagram, the oldest state is (re-)used. 18628679Sbrian */ 18728679Sbrian register struct cstate *lcs; 18828679Sbrian register struct cstate *lastcs = comp->last_cs; 1896059Samurai 19028679Sbrian do { 19128679Sbrian lcs = cs; 19228679Sbrian cs = cs->cs_next; 19336285Sbrian slstat->sls_searches++; 19436285Sbrian if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 19536285Sbrian && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 19636285Sbrian && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 19728679Sbrian goto found; 19828679Sbrian } while (cs != lastcs); 1996059Samurai 20028679Sbrian /* 20128679Sbrian * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 20228679Sbrian * that tells the other side what connection number we're using for this 20328679Sbrian * conversation. Note that since the state list is circular, the oldest 20428679Sbrian * state points to the newest and we only need to set last_cs to update 20528679Sbrian * the lru linkage. 20628679Sbrian */ 20736285Sbrian slstat->sls_misses++; 20828679Sbrian comp->last_cs = lcs; 2096059Samurai#define THOFFSET(th) (th->th_off) 21028679Sbrian hlen += th->th_off; 21128679Sbrian hlen <<= 2; 21228679Sbrian if (hlen > m->cnt) 21328679Sbrian return (TYPE_IP); 21428679Sbrian goto uncompressed; 2156059Samurai 21628679Sbrianfound: 2176059Samurai 21828679Sbrian /* 21928679Sbrian * Found it -- move to the front on the connection list. 22028679Sbrian */ 22128679Sbrian if (cs == lastcs) 22228679Sbrian comp->last_cs = lcs; 22328679Sbrian else { 22428679Sbrian lcs->cs_next = cs->cs_next; 22528679Sbrian cs->cs_next = lastcs->cs_next; 22628679Sbrian lastcs->cs_next = cs; 22728679Sbrian } 22828679Sbrian } 2296059Samurai 23028679Sbrian /* 23128679Sbrian * Make sure that only what we expect to change changed. The first line of 23228679Sbrian * the `if' checks the IP protocol version, header length & type of 23328679Sbrian * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 23428679Sbrian * checks the time-to-live and protocol (the protocol check is unnecessary 23528679Sbrian * but costless). The 4th line checks the TCP header length. The 5th line 23628679Sbrian * checks IP options, if any. The 6th line checks TCP options, if any. If 23728679Sbrian * any of these things are different between the previous & current 23828679Sbrian * datagram, we send the current datagram `uncompressed'. 23928679Sbrian */ 24028679Sbrian oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 24128679Sbrian deltaS = hlen; 24228679Sbrian hlen += th->th_off; 24328679Sbrian hlen <<= 2; 24428679Sbrian if (hlen > m->cnt) 24528679Sbrian return (TYPE_IP); 2466059Samurai 24728679Sbrian if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 24828679Sbrian ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 24928679Sbrian ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 25028679Sbrian THOFFSET(th) != THOFFSET(oth) || 25128679Sbrian (deltaS > 5 && 25230715Sbrian memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 25328679Sbrian (THOFFSET(th) > 5 && 25430715Sbrian memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 25528679Sbrian goto uncompressed; 25628679Sbrian } 2576059Samurai 25828679Sbrian /* 25928679Sbrian * Figure out which of the changing fields changed. The receiver expects 26028679Sbrian * changes in the order: urgent, window, ack, seq (the order minimizes the 26128679Sbrian * number of temporaries needed in this section of code). 26228679Sbrian */ 26328679Sbrian if (th->th_flags & TH_URG) { 26428679Sbrian deltaS = ntohs(th->th_urp); 26528679Sbrian ENCODEZ(deltaS); 26628679Sbrian changes |= NEW_U; 26728679Sbrian } else if (th->th_urp != oth->th_urp) { 2686059Samurai 26928679Sbrian /* 27028679Sbrian * argh! URG not set but urp changed -- a sensible implementation should 27128679Sbrian * never do this but RFC793 doesn't prohibit the change so we have to 27228679Sbrian * deal with it. 27328679Sbrian */ 27428679Sbrian goto uncompressed; 27528679Sbrian } 27628679Sbrian deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 27728679Sbrian if (deltaS) { 27828679Sbrian ENCODE(deltaS); 27928679Sbrian changes |= NEW_W; 28028679Sbrian } 28128679Sbrian deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 28228679Sbrian if (deltaA) { 28328679Sbrian if (deltaA > 0xffff) { 28428679Sbrian goto uncompressed; 28528679Sbrian } 28628679Sbrian ENCODE(deltaA); 28728679Sbrian changes |= NEW_A; 28828679Sbrian } 28928679Sbrian deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29028679Sbrian if (deltaS) { 29128679Sbrian if (deltaS > 0xffff) { 29228679Sbrian goto uncompressed; 29328679Sbrian } 29428679Sbrian ENCODE(deltaS); 29528679Sbrian changes |= NEW_S; 29628679Sbrian } 29728679Sbrian switch (changes) { 2986059Samurai 29928679Sbrian case 0: 3006059Samurai 30128679Sbrian /* 30228679Sbrian * Nothing changed. If this packet contains data and the last one didn't, 30328679Sbrian * this is probably a data packet following an ack (normal on an 30428679Sbrian * interactive connection) and we send it compressed. Otherwise it's 30528679Sbrian * probably a retransmit, retransmitted ack or window probe. Send it 30628679Sbrian * uncompressed in case the other side missed the compressed version. 30728679Sbrian */ 30828679Sbrian if (ip->ip_len != cs->cs_ip.ip_len && 30928679Sbrian ntohs(cs->cs_ip.ip_len) == hlen) 31028679Sbrian break; 3116059Samurai 31228679Sbrian /* (fall through) */ 3136059Samurai 31428679Sbrian case SPECIAL_I: 31528679Sbrian case SPECIAL_D: 3166059Samurai 31728679Sbrian /* 31828679Sbrian * actual changes match one of our special case encodings -- send packet 31928679Sbrian * uncompressed. 32028679Sbrian */ 32128679Sbrian goto uncompressed; 3226059Samurai 32328679Sbrian case NEW_S | NEW_A: 32428679Sbrian if (deltaS == deltaA && 32528679Sbrian deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 32628679Sbrian /* special case for echoed terminal traffic */ 32728679Sbrian changes = SPECIAL_I; 32828679Sbrian cp = new_seq; 32928679Sbrian } 33028679Sbrian break; 3316059Samurai 33228679Sbrian case NEW_S: 33328679Sbrian if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33428679Sbrian /* special case for data xfer */ 33528679Sbrian changes = SPECIAL_D; 33628679Sbrian cp = new_seq; 33728679Sbrian } 33828679Sbrian break; 33928679Sbrian } 3406059Samurai 34128679Sbrian deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 34228679Sbrian if (deltaS != 1) { 34328679Sbrian ENCODEZ(deltaS); 34428679Sbrian changes |= NEW_I; 34528679Sbrian } 34628679Sbrian if (th->th_flags & TH_PUSH) 34728679Sbrian changes |= TCP_PUSH_BIT; 3486059Samurai 34928679Sbrian /* 35028679Sbrian * Grab the cksum before we overwrite it below. Then update our state with 35128679Sbrian * this packet's header. 35228679Sbrian */ 35328679Sbrian deltaA = ntohs(th->th_sum); 35430715Sbrian memcpy(&cs->cs_ip, ip, hlen); 3556059Samurai 35628679Sbrian /* 35728679Sbrian * We want to use the original packet as our compressed packet. (cp - 35828679Sbrian * new_seq) is the number of bytes we need for compressed sequence numbers. 35928679Sbrian * In addition we need one byte for the change mask, one for the connection 36028679Sbrian * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 36128679Sbrian * are needed. hlen is how many bytes of the original packet to toss so 36228679Sbrian * subtract the two to get the new packet size. 36328679Sbrian */ 36428679Sbrian deltaS = cp - new_seq; 36528679Sbrian cp = (u_char *) ip; 36628679Sbrian 36728679Sbrian /* 36828679Sbrian * Since fastq traffic can jump ahead of the background traffic, we don't 36928679Sbrian * know what order packets will go on the line. In this case, we always 37028679Sbrian * send a "new" connection id so the receiver state stays synchronized. 37128679Sbrian */ 37230187Sbrian if (comp->last_xmit == cs->cs_id && compress_cid) { 37328679Sbrian hlen -= deltaS + 3; 37428679Sbrian cp += hlen; 37528679Sbrian *cp++ = changes; 37630187Sbrian } else { 37728679Sbrian comp->last_xmit = cs->cs_id; 37828679Sbrian hlen -= deltaS + 4; 37928679Sbrian cp += hlen; 38028679Sbrian *cp++ = changes | NEW_C; 38128679Sbrian *cp++ = cs->cs_id; 38228679Sbrian } 38328679Sbrian m->cnt -= hlen; 38428679Sbrian m->offset += hlen; 38528679Sbrian *cp++ = deltaA >> 8; 38628679Sbrian *cp++ = deltaA; 38730715Sbrian memcpy(cp, new_seq, deltaS); 38836285Sbrian slstat->sls_compressed++; 38936285Sbrian return (TYPE_COMPRESSED_TCP); 3906059Samurai 39128679Sbrian /* 39228679Sbrian * Update connection state cs & send uncompressed packet ('uncompressed' 39328679Sbrian * means a regular ip/tcp packet but with the 'conversation id' we hope to 39428679Sbrian * use on future compressed packets in the protocol field). 39528679Sbrian */ 3966059Samuraiuncompressed: 39730715Sbrian memcpy(&cs->cs_ip, ip, hlen); 39828679Sbrian ip->ip_p = cs->cs_id; 39928679Sbrian comp->last_xmit = cs->cs_id; 40028679Sbrian return (TYPE_UNCOMPRESSED_TCP); 4016059Samurai} 4026059Samurai 4036059Samurai 4046059Samuraiint 40536960Sbriansl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 40636960Sbrian struct slstat *slstat, int max_state) 4076059Samurai{ 40828679Sbrian register u_char *cp; 40928679Sbrian register u_int hlen, changes; 41028679Sbrian register struct tcphdr *th; 41128679Sbrian register struct cstate *cs; 41228679Sbrian register struct ip *ip; 4136059Samurai 41428679Sbrian switch (type) { 4156059Samurai 41628679Sbrian case TYPE_UNCOMPRESSED_TCP: 41728679Sbrian ip = (struct ip *) * bufp; 41836960Sbrian if (ip->ip_p > max_state) 41928679Sbrian goto bad; 42028679Sbrian cs = &comp->rstate[comp->last_recv = ip->ip_p]; 42128679Sbrian comp->flags &= ~SLF_TOSS; 42228679Sbrian ip->ip_p = IPPROTO_TCP; 4236059Samurai 42428679Sbrian /* 42528679Sbrian * Calculate the size of the TCP/IP header and make sure that we don't 42628679Sbrian * overflow the space we have available for it. 42728679Sbrian */ 42828679Sbrian hlen = ip->ip_hl << 2; 42928679Sbrian if (hlen + sizeof(struct tcphdr) > len) 43028679Sbrian goto bad; 43128679Sbrian th = (struct tcphdr *) & ((char *) ip)[hlen]; 43228679Sbrian hlen += THOFFSET(th) << 2; 43328679Sbrian if (hlen > MAX_HDR) 43428679Sbrian goto bad; 43530715Sbrian memcpy(&cs->cs_ip, ip, hlen); 43630357Sbrian cs->cs_ip.ip_sum = 0; 43728679Sbrian cs->cs_hlen = hlen; 43836285Sbrian slstat->sls_uncompressedin++; 43936285Sbrian return (len); 4406059Samurai 44128679Sbrian default: 44228679Sbrian goto bad; 4436059Samurai 44428679Sbrian case TYPE_COMPRESSED_TCP: 44528679Sbrian break; 44628679Sbrian } 44728679Sbrian /* We've got a compressed packet. */ 44836285Sbrian slstat->sls_compressedin++; 44936285Sbrian cp = *bufp; 45028679Sbrian changes = *cp++; 45136285Sbrian log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 45228679Sbrian if (changes & NEW_C) { 4536059Samurai 45428679Sbrian /* 45528679Sbrian * Make sure the state index is in range, then grab the state. If we have 45628679Sbrian * a good state index, clear the 'discard' flag. 45728679Sbrian */ 45836960Sbrian if (*cp > max_state || comp->last_recv == 255) { 45928679Sbrian goto bad; 46036960Sbrian } 4616059Samurai 46228679Sbrian comp->flags &= ~SLF_TOSS; 46328679Sbrian comp->last_recv = *cp++; 46428679Sbrian } else { 4656059Samurai 46628679Sbrian /* 46728679Sbrian * this packet has an implicit state index. If we've had a line error 46828679Sbrian * since the last time we got an explicit state index, we have to toss 46928679Sbrian * the packet. 47028679Sbrian */ 47128679Sbrian if (comp->flags & SLF_TOSS) { 47236285Sbrian slstat->sls_tossed++; 47336285Sbrian return (0); 47428679Sbrian } 47528679Sbrian } 47628679Sbrian cs = &comp->rstate[comp->last_recv]; 47728679Sbrian hlen = cs->cs_ip.ip_hl << 2; 47836960Sbrian if (hlen == 0) 47936960Sbrian goto bad; /* We've been pointed at a not-yet-used slot ! */ 48028679Sbrian th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 48128679Sbrian th->th_sum = htons((*cp << 8) | cp[1]); 48228679Sbrian cp += 2; 48328679Sbrian if (changes & TCP_PUSH_BIT) 48428679Sbrian th->th_flags |= TH_PUSH; 48528679Sbrian else 48628679Sbrian th->th_flags &= ~TH_PUSH; 48728679Sbrian 48828679Sbrian switch (changes & SPECIALS_MASK) { 48928679Sbrian case SPECIAL_I: 49028679Sbrian { 49128679Sbrian register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 49228679Sbrian 49328679Sbrian th->th_ack = htonl(ntohl(th->th_ack) + i); 49428679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + i); 49528679Sbrian } 49628679Sbrian break; 49728679Sbrian 49828679Sbrian case SPECIAL_D: 49928679Sbrian th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 50028679Sbrian - cs->cs_hlen); 50128679Sbrian break; 50228679Sbrian 50328679Sbrian default: 50428679Sbrian if (changes & NEW_U) { 50528679Sbrian th->th_flags |= TH_URG; 50628679Sbrian DECODEU(th->th_urp) 50728679Sbrian } else 50828679Sbrian th->th_flags &= ~TH_URG; 50928679Sbrian if (changes & NEW_W) 51028679Sbrian DECODES(th->th_win) 51128679Sbrian if (changes & NEW_A) 51228679Sbrian DECODEL(th->th_ack) 51328679Sbrian if (changes & NEW_S) { 51436285Sbrian log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 51528679Sbrian *cp, cp[1], cp[2]); 51628679Sbrian DECODEL(th->th_seq) 5176059Samurai } 51828679Sbrian break; 51928679Sbrian } 52028679Sbrian if (changes & NEW_I) { 52128679Sbrian DECODES(cs->cs_ip.ip_id) 52228679Sbrian } else 52328679Sbrian cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 5246059Samurai 52536285Sbrian log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 52636285Sbrian cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 52726516Sbrian 52828679Sbrian /* 52928679Sbrian * At this point, cp points to the first byte of data in the packet. If 53028679Sbrian * we're not aligned on a 4-byte boundary, copy the data down so the ip & 53128679Sbrian * tcp headers will be aligned. Then back up cp by the tcp/ip header 53228679Sbrian * length to make room for the reconstructed header (we assume the packet 53328679Sbrian * we were handed has enough space to prepend 128 bytes of header). Adjust 53428679Sbrian * the length to account for the new header & fill in the IP total length. 53528679Sbrian */ 53628679Sbrian len -= (cp - *bufp); 53728679Sbrian if (len < 0) 5386059Samurai 53928679Sbrian /* 54028679Sbrian * we must have dropped some characters (crc should detect this but the 54128679Sbrian * old slip framing won't) 54228679Sbrian */ 54328679Sbrian goto bad; 54428679Sbrian 5456059Samurai#ifdef notdef 54628679Sbrian if ((int) cp & 3) { 54728679Sbrian if (len > 0) 54830715Sbrian (void) bcopy(cp, (caddr_t) ((int) cp & ~3), len); 54928679Sbrian cp = (u_char *) ((int) cp & ~3); 55028679Sbrian } 5516059Samurai#endif 5526059Samurai 55328679Sbrian cp -= cs->cs_hlen; 55428679Sbrian len += cs->cs_hlen; 55528679Sbrian cs->cs_ip.ip_len = htons(len); 55630715Sbrian memcpy(cp, &cs->cs_ip, cs->cs_hlen); 55728679Sbrian *bufp = cp; 5586059Samurai 55928679Sbrian /* recompute the ip header checksum */ 56028679Sbrian { 56128679Sbrian register u_short *bp = (u_short *) cp; 56228679Sbrian 56328679Sbrian for (changes = 0; hlen > 0; hlen -= 2) 56428679Sbrian changes += *bp++; 56528679Sbrian changes = (changes & 0xffff) + (changes >> 16); 56628679Sbrian changes = (changes & 0xffff) + (changes >> 16); 56728679Sbrian ((struct ip *) cp)->ip_sum = ~changes; 56828679Sbrian } 56928679Sbrian return (len); 5706059Samuraibad: 57128679Sbrian comp->flags |= SLF_TOSS; 57236285Sbrian slstat->sls_errorin++; 57336285Sbrian return (0); 5746059Samurai} 5756059Samurai 5766059Samuraiint 57736285Sbriansl_Show(struct cmdargs const *arg) 5786059Samurai{ 57936285Sbrian prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 58036285Sbrian prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 58136285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 58236285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 58336285Sbrian prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 58436285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 58536285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 58636285Sbrian prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 58736285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 58836285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 58936285Sbrian prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 59036285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 59136285Sbrian arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 59226516Sbrian return 0; 5936059Samurai} 594