slcompress.c revision 98243
167754Smsmith/* 267754Smsmith * Routines to compress and uncompess tcp packets (for transmission 367754Smsmith * over low speed serial lines. 4129684Snjl * 567754Smsmith * Copyright (c) 1989 Regents of the University of California. 667754Smsmith * All rights reserved. 767754Smsmith * 867754Smsmith * Redistribution and use in source and binary forms are permitted 967754Smsmith * provided that the above copyright notice and this paragraph are 1067754Smsmith * duplicated in all such forms and that any documentation, 1167754Smsmith * advertising materials, and other materials related to such 12126372Snjl * distribution and use acknowledge that the software was developed 1370243Smsmith * by the University of California, Berkeley. The name of the 1467754Smsmith * University may not be used to endorse or promote products derived 1567754Smsmith * from this software without specific prior written permission. 1667754Smsmith * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 1767754Smsmith * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 1867754Smsmith * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 1967754Smsmith * 2067754Smsmith * $FreeBSD: head/usr.sbin/ppp/slcompress.c 98243 2002-06-15 08:03:30Z brian $ 2167754Smsmith * 2267754Smsmith * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 2367754Smsmith * - Initial distribution. 2467754Smsmith */ 2567754Smsmith 2667754Smsmith#include <sys/param.h> 2767754Smsmith#include <netinet/in_systm.h> 2867754Smsmith#include <netinet/in.h> 2967754Smsmith#include <netinet/tcp.h> 3067754Smsmith#include <netinet/ip.h> 3167754Smsmith#include <sys/socket.h> 3267754Smsmith#include <sys/un.h> 3367754Smsmith 3467754Smsmith#include <stdio.h> 3567754Smsmith#include <string.h> 3667754Smsmith#include <termios.h> 3767754Smsmith 3867754Smsmith#include "layer.h" 3967754Smsmith#include "defs.h" 4067754Smsmith#include "command.h" 4167754Smsmith#include "mbuf.h" 4267754Smsmith#include "log.h" 4367754Smsmith#include "slcompress.h" 4467754Smsmith#include "descriptor.h" 4567754Smsmith#include "prompt.h" 4667754Smsmith#include "timer.h" 4767754Smsmith#include "fsm.h" 4867754Smsmith#include "throughput.h" 4967754Smsmith#include "iplist.h" 5067754Smsmith#include "lqr.h" 5167754Smsmith#include "hdlc.h" 5267754Smsmith#include "ncpaddr.h" 5367754Smsmith#include "ipcp.h" 5467754Smsmith#include "filter.h" 5567754Smsmith#include "lcp.h" 5667754Smsmith#include "ccp.h" 5767754Smsmith#include "link.h" 5867754Smsmith#include "mp.h" 5967754Smsmith#ifndef NORADIUS 6067754Smsmith#include "radius.h" 6167754Smsmith#endif 6267754Smsmith#include "ipv6cp.h" 6367754Smsmith#include "ncp.h" 6467754Smsmith#include "bundle.h" 6567754Smsmith 6667754Smsmithvoid 6767754Smsmithsl_compress_init(struct slcompress *comp, int max_state) 6867754Smsmith{ 6967754Smsmith register u_int i; 7067754Smsmith register struct cstate *tstate = comp->tstate; 7167754Smsmith 7267754Smsmith memset(comp, '\0', sizeof *comp); 7367754Smsmith for (i = max_state; i > 0; --i) { 7467754Smsmith tstate[i].cs_id = i; 7567754Smsmith tstate[i].cs_next = &tstate[i - 1]; 7667754Smsmith } 7767754Smsmith tstate[0].cs_next = &tstate[max_state]; 7867754Smsmith tstate[0].cs_id = 0; 7967754Smsmith comp->last_cs = &tstate[0]; 8067754Smsmith comp->last_recv = 255; 8167754Smsmith comp->last_xmit = 255; 8267754Smsmith comp->flags = SLF_TOSS; 8367754Smsmith} 8467754Smsmith 8567754Smsmith 8667754Smsmith/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 8767754Smsmith * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 8867754Smsmith * form). 8967754Smsmith */ 9067754Smsmith#define ENCODE(n) { \ 9167754Smsmith if ((u_short)(n) >= 256) { \ 9267754Smsmith *cp++ = 0; \ 9367754Smsmith cp[1] = (n); \ 9467754Smsmith cp[0] = (n) >> 8; \ 9567754Smsmith cp += 2; \ 9667754Smsmith } else { \ 9767754Smsmith *cp++ = (n); \ 9867754Smsmith } \ 9967754Smsmith} 10067754Smsmith#define ENCODEZ(n) { \ 10167754Smsmith if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 10267754Smsmith *cp++ = 0; \ 10367754Smsmith cp[1] = (n); \ 10467754Smsmith cp[0] = (n) >> 8; \ 10567754Smsmith cp += 2; \ 10667754Smsmith } else { \ 10767754Smsmith *cp++ = (n); \ 10867754Smsmith } \ 10967754Smsmith} 11067754Smsmith 11167754Smsmith#define DECODEL(f) { \ 11267754Smsmith if (*cp == 0) {\ 11367754Smsmith (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 11467754Smsmith cp += 3; \ 11567754Smsmith } else { \ 11667754Smsmith (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 11767754Smsmith } \ 11867754Smsmith} 11967754Smsmith 12067754Smsmith#define DECODES(f) { \ 12167754Smsmith if (*cp == 0) {\ 12267754Smsmith (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 12367754Smsmith cp += 3; \ 12477424Smsmith } else { \ 12591116Smsmith (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 12667754Smsmith } \ 12767754Smsmith} 12867754Smsmith 12967754Smsmith#define DECODEU(f) { \ 13067754Smsmith if (*cp == 0) {\ 13167754Smsmith (f) = htons((cp[1] << 8) | cp[2]); \ 13283174Smsmith cp += 3; \ 13367754Smsmith } else { \ 13467754Smsmith (f) = htons((u_int32_t)*cp++); \ 13567754Smsmith } \ 13683174Smsmith} 13767754Smsmith 13867754Smsmith 13967754Smsmithu_char 14067754Smsmithsl_compress_tcp(struct mbuf * m, 14167754Smsmith struct ip * ip, 14284491Smsmith struct slcompress *comp, 14367754Smsmith struct slstat *slstat, 14467754Smsmith int compress_cid) 14567754Smsmith{ 14683174Smsmith register struct cstate *cs = comp->last_cs->cs_next; 14791116Smsmith register u_int hlen = ip->ip_hl; 14867754Smsmith register struct tcphdr *oth; 14967754Smsmith register struct tcphdr *th; 15080062Smsmith register u_int deltaS, deltaA; 15167754Smsmith register u_int changes = 0; 15267754Smsmith u_char new_seq[16]; 15367754Smsmith register u_char *cp = new_seq; 15467754Smsmith 15567754Smsmith /* 15682367Smsmith * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 15767754Smsmith * (i.e., ACK isn't set or some other control bit is set). (We assume that 15899146Siwasaki * the caller has already made sure the packet is IP proto TCP). 15967754Smsmith */ 16091116Smsmith if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) { 16167754Smsmith log_Printf(LogDEBUG, "??? 1 ip_off = %x, m_len = %lu\n", 16267754Smsmith ip->ip_off, (unsigned long)m->m_len); 16367754Smsmith log_DumpBp(LogDEBUG, "", m); 16467754Smsmith return (TYPE_IP); 16567754Smsmith } 16667754Smsmith th = (struct tcphdr *) & ((int *) ip)[hlen]; 16767754Smsmith if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 16867754Smsmith log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 16967754Smsmith log_DumpBp(LogDEBUG, "", m); 17083174Smsmith return (TYPE_IP); 17167754Smsmith } 17267754Smsmith 17367754Smsmith /* 17483174Smsmith * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 17567754Smsmith * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 17667754Smsmith * connection state. Special case the most recently used connection since 17767754Smsmith * it's most likely to be used again & we don't have to do any reordering 17867754Smsmith * if it's used. 17967754Smsmith */ 18067754Smsmith slstat->sls_packets++; 18167754Smsmith if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 18267754Smsmith ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 18367754Smsmith *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 18467754Smsmith 18567754Smsmith /* 18667754Smsmith * Wasn't the first -- search for it. 18791116Smsmith * 18867754Smsmith * States are kept in a circularly linked list with last_cs pointing to the 18983174Smsmith * end of the list. The list is kept in lru order by moving a state to 19091116Smsmith * the head of the list whenever it is referenced. Since the list is 19167754Smsmith * short and, empirically, the connection we want is almost always near 19267754Smsmith * the front, we locate states via linear search. If we don't find a 19367754Smsmith * state for the datagram, the oldest state is (re-)used. 19467754Smsmith */ 195115351Snjl register struct cstate *lcs; 196115351Snjl register struct cstate *lastcs = comp->last_cs; 19767754Smsmith 19867754Smsmith do { 19967754Smsmith lcs = cs; 20067754Smsmith cs = cs->cs_next; 20167754Smsmith slstat->sls_searches++; 20267754Smsmith if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 20367754Smsmith && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 20467754Smsmith && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 205115351Snjl goto found; 206115351Snjl } while (cs != lastcs); 20767754Smsmith 20867754Smsmith /* 20967754Smsmith * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 21067754Smsmith * that tells the other side what connection number we're using for this 21167754Smsmith * conversation. Note that since the state list is circular, the oldest 21267754Smsmith * state points to the newest and we only need to set last_cs to update 21367754Smsmith * the lru linkage. 21467754Smsmith */ 215115351Snjl slstat->sls_misses++; 216115351Snjl comp->last_cs = lcs; 217115351Snjl#define THOFFSET(th) (th->th_off) 218115351Snjl hlen += th->th_off; 219115351Snjl hlen <<= 2; 220115351Snjl if (hlen > m->m_len) 221115351Snjl return (TYPE_IP); 222115351Snjl goto uncompressed; 223115351Snjl 224115351Snjlfound: 225115351Snjl 226115351Snjl /* 227115351Snjl * Found it -- move to the front on the connection list. 22867754Smsmith */ 22967754Smsmith if (cs == lastcs) 23067754Smsmith comp->last_cs = lcs; 23182367Smsmith else { 23267754Smsmith lcs->cs_next = cs->cs_next; 23367754Smsmith cs->cs_next = lastcs->cs_next; 23487031Smsmith lastcs->cs_next = cs; 23567754Smsmith } 23687031Smsmith } 23780062Smsmith 23867754Smsmith /* 23967754Smsmith * Make sure that only what we expect to change changed. The first line of 24067754Smsmith * the `if' checks the IP protocol version, header length & type of 24167754Smsmith * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 242107325Siwasaki * checks the time-to-live and protocol (the protocol check is unnecessary 24367754Smsmith * but costless). The 4th line checks the TCP header length. The 5th line 24467754Smsmith * checks IP options, if any. The 6th line checks TCP options, if any. If 245114237Snjl * any of these things are different between the previous & current 246107325Siwasaki * datagram, we send the current datagram `uncompressed'. 247107325Siwasaki */ 248107325Siwasaki oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 249107325Siwasaki deltaS = hlen; 250107325Siwasaki hlen += th->th_off; 251107325Siwasaki hlen <<= 2; 252114237Snjl if (hlen > m->m_len) 253107325Siwasaki return (TYPE_IP); 254107325Siwasaki 255107325Siwasaki if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 256107325Siwasaki ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 257107325Siwasaki ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 258107325Siwasaki THOFFSET(th) != THOFFSET(oth) || 259107325Siwasaki (deltaS > 5 && 260107325Siwasaki memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 261107325Siwasaki (THOFFSET(th) > 5 && 262107325Siwasaki memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 263107325Siwasaki goto uncompressed; 264107325Siwasaki } 265107325Siwasaki 266107325Siwasaki /* 267107325Siwasaki * Figure out which of the changing fields changed. The receiver expects 268107325Siwasaki * changes in the order: urgent, window, ack, seq (the order minimizes the 269107325Siwasaki * number of temporaries needed in this section of code). 270107325Siwasaki */ 271107325Siwasaki if (th->th_flags & TH_URG) { 272107325Siwasaki deltaS = ntohs(th->th_urp); 273107325Siwasaki ENCODEZ(deltaS); 274107325Siwasaki changes |= NEW_U; 275107325Siwasaki } else if (th->th_urp != oth->th_urp) { 276107325Siwasaki 277107325Siwasaki /* 278107325Siwasaki * argh! URG not set but urp changed -- a sensible implementation should 279107325Siwasaki * never do this but RFC793 doesn't prohibit the change so we have to 280107325Siwasaki * deal with it. 281107325Siwasaki */ 282107325Siwasaki goto uncompressed; 283107325Siwasaki } 284107325Siwasaki deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 285107325Siwasaki if (deltaS) { 286107325Siwasaki ENCODE(deltaS); 287107325Siwasaki changes |= NEW_W; 288107325Siwasaki } 289107325Siwasaki deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 290107325Siwasaki if (deltaA) { 291107325Siwasaki if (deltaA > 0xffff) { 292107325Siwasaki goto uncompressed; 293107325Siwasaki } 294107325Siwasaki ENCODE(deltaA); 295107325Siwasaki changes |= NEW_A; 296107325Siwasaki } 297107325Siwasaki deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 29867754Smsmith if (deltaS) { 29967754Smsmith if (deltaS > 0xffff) { 30067754Smsmith goto uncompressed; 30167754Smsmith } 30283174Smsmith ENCODE(deltaS); 30367754Smsmith changes |= NEW_S; 30467754Smsmith } 30567754Smsmith switch (changes) { 30667754Smsmith 30787031Smsmith case 0: 30887031Smsmith 30967754Smsmith /* 310107325Siwasaki * Nothing changed. If this packet contains data and the last one didn't, 311107325Siwasaki * this is probably a data packet following an ack (normal on an 312107325Siwasaki * interactive connection) and we send it compressed. Otherwise it's 313107325Siwasaki * probably a retransmit, retransmitted ack or window probe. Send it 31487031Smsmith * uncompressed in case the other side missed the compressed version. 31567754Smsmith */ 31667754Smsmith if (ip->ip_len != cs->cs_ip.ip_len && 31767754Smsmith ntohs(cs->cs_ip.ip_len) == hlen) 31867754Smsmith break; 31967754Smsmith 32067754Smsmith /* (fall through) */ 32183174Smsmith 32291116Smsmith case SPECIAL_I: 32367754Smsmith case SPECIAL_D: 324117521Snjl 32567754Smsmith /* 326107325Siwasaki * actual changes match one of our special case encodings -- send packet 32767754Smsmith * uncompressed. 328107325Siwasaki */ 329107325Siwasaki goto uncompressed; 33067754Smsmith 331107325Siwasaki case NEW_S | NEW_A: 33291116Smsmith if (deltaS == deltaA && 33367754Smsmith deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 33467754Smsmith /* special case for echoed terminal traffic */ 33567754Smsmith changes = SPECIAL_I; 33667754Smsmith cp = new_seq; 33767754Smsmith } 33867754Smsmith break; 33967754Smsmith 34067754Smsmith case NEW_S: 34167754Smsmith if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 34267754Smsmith /* special case for data xfer */ 34367754Smsmith changes = SPECIAL_D; 34467754Smsmith cp = new_seq; 34587031Smsmith } 34667754Smsmith break; 34767754Smsmith } 34867754Smsmith 34967754Smsmith deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 35067754Smsmith if (deltaS != 1) { 351107325Siwasaki ENCODEZ(deltaS); 352107325Siwasaki changes |= NEW_I; 35367754Smsmith } 35467754Smsmith if (th->th_flags & TH_PUSH) 35567754Smsmith changes |= TCP_PUSH_BIT; 356107325Siwasaki 357107325Siwasaki /* 358129684Snjl * Grab the cksum before we overwrite it below. Then update our state with 359107325Siwasaki * this packet's header. 360107325Siwasaki */ 361107325Siwasaki deltaA = ntohs(th->th_sum); 362123315Snjl memcpy(&cs->cs_ip, ip, hlen); 363107325Siwasaki 364107325Siwasaki /* 365107325Siwasaki * We want to use the original packet as our compressed packet. (cp - 366107325Siwasaki * new_seq) is the number of bytes we need for compressed sequence numbers. 367107325Siwasaki * In addition we need one byte for the change mask, one for the connection 368107325Siwasaki * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 369107325Siwasaki * are needed. hlen is how many bytes of the original packet to toss so 370107325Siwasaki * subtract the two to get the new packet size. 371107325Siwasaki */ 372107325Siwasaki deltaS = cp - new_seq; 373107325Siwasaki cp = (u_char *) ip; 374107325Siwasaki 375107325Siwasaki /* 376107325Siwasaki * Since fastq traffic can jump ahead of the background traffic, we don't 377107325Siwasaki * know what order packets will go on the line. In this case, we always 378107325Siwasaki * send a "new" connection id so the receiver state stays synchronized. 379107325Siwasaki */ 380107325Siwasaki if (comp->last_xmit == cs->cs_id && compress_cid) { 381107325Siwasaki hlen -= deltaS + 3; 382107325Siwasaki cp += hlen; 383107325Siwasaki *cp++ = changes; 384107325Siwasaki } else { 385107325Siwasaki comp->last_xmit = cs->cs_id; 386107325Siwasaki hlen -= deltaS + 4; 387107325Siwasaki cp += hlen; 388107325Siwasaki *cp++ = changes | NEW_C; 389107325Siwasaki *cp++ = cs->cs_id; 390107325Siwasaki } 391114237Snjl m->m_len -= hlen; 392107325Siwasaki m->m_offset += hlen; 393107325Siwasaki *cp++ = deltaA >> 8; 394107325Siwasaki *cp++ = deltaA; 395107325Siwasaki memcpy(cp, new_seq, deltaS); 396107325Siwasaki slstat->sls_compressed++; 397107325Siwasaki return (TYPE_COMPRESSED_TCP); 398107325Siwasaki 399107325Siwasaki /* 400107325Siwasaki * Update connection state cs & send uncompressed packet ('uncompressed' 401107325Siwasaki * means a regular ip/tcp packet but with the 'conversation id' we hope to 402107325Siwasaki * use on future compressed packets in the protocol field). 403107325Siwasaki */ 404107325Siwasakiuncompressed: 405107325Siwasaki memcpy(&cs->cs_ip, ip, hlen); 406107325Siwasaki ip->ip_p = cs->cs_id; 407107325Siwasaki comp->last_xmit = cs->cs_id; 408107325Siwasaki return (TYPE_UNCOMPRESSED_TCP); 409107325Siwasaki} 410107325Siwasaki 41167754Smsmith 41267754Smsmithint 41367754Smsmithsl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 41467754Smsmith struct slstat *slstat, int max_state) 41567754Smsmith{ 41667754Smsmith register u_char *cp; 41767754Smsmith register u_int hlen, changes; 41867754Smsmith register struct tcphdr *th; 41967754Smsmith register struct cstate *cs; 42067754Smsmith register struct ip *ip; 421107325Siwasaki u_short *bp; 422107325Siwasaki 423107325Siwasaki switch (type) { 42467754Smsmith 42567754Smsmith case TYPE_UNCOMPRESSED_TCP: 42667754Smsmith ip = (struct ip *) * bufp; 42767754Smsmith if (ip->ip_p > max_state) 428107325Siwasaki goto bad; 429107325Siwasaki cs = &comp->rstate[comp->last_recv = ip->ip_p]; 43067754Smsmith comp->flags &= ~SLF_TOSS; 431129684Snjl ip->ip_p = IPPROTO_TCP; 432127175Snjl 433127175Snjl /* 434123315Snjl * Calculate the size of the TCP/IP header and make sure that we don't 435127175Snjl * overflow the space we have available for it. 43667754Smsmith */ 43767754Smsmith hlen = ip->ip_hl << 2; 43867754Smsmith if (hlen + sizeof(struct tcphdr) > len) 43967754Smsmith goto bad; 44067754Smsmith th = (struct tcphdr *) & ((char *) ip)[hlen]; 44191116Smsmith hlen += THOFFSET(th) << 2; 44267754Smsmith if (hlen > MAX_HDR) 44367754Smsmith goto bad; 44467754Smsmith memcpy(&cs->cs_ip, ip, hlen); 44567754Smsmith cs->cs_hlen = hlen; 44667754Smsmith slstat->sls_uncompressedin++; 44767754Smsmith return (len); 44867754Smsmith 44967754Smsmith default: 45067754Smsmith goto bad; 45167754Smsmith 45267754Smsmith case TYPE_COMPRESSED_TCP: 45367754Smsmith break; 45467754Smsmith } 45567754Smsmith 45667754Smsmith /* We've got a compressed packet. */ 45767754Smsmith slstat->sls_compressedin++; 45891116Smsmith cp = *bufp; 45991116Smsmith changes = *cp++; 46067754Smsmith log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 46167754Smsmith 46267754Smsmith if (changes & NEW_C) { 46367754Smsmith /* 46467754Smsmith * Make sure the state index is in range, then grab the state. If we have 46567754Smsmith * a good state index, clear the 'discard' flag. 46667754Smsmith */ 46767754Smsmith if (*cp > max_state || comp->last_recv == 255) 46867754Smsmith goto bad; 469115351Snjl 47067754Smsmith comp->flags &= ~SLF_TOSS; 47167754Smsmith comp->last_recv = *cp++; 47267754Smsmith } else { 47391116Smsmith /* 47467754Smsmith * this packet has an implicit state index. If we've had a line error 47567754Smsmith * since the last time we got an explicit state index, we have to toss 47667754Smsmith * the packet. 47767754Smsmith */ 47867754Smsmith if (comp->flags & SLF_TOSS) { 47967754Smsmith slstat->sls_tossed++; 48067754Smsmith return (0); 48167754Smsmith } 48267754Smsmith } 48367754Smsmith cs = &comp->rstate[comp->last_recv]; 48467754Smsmith hlen = cs->cs_ip.ip_hl << 2; 48567754Smsmith th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 48667754Smsmith th->th_sum = htons((*cp << 8) | cp[1]); 48767754Smsmith cp += 2; 48867754Smsmith if (changes & TCP_PUSH_BIT) 48967754Smsmith th->th_flags |= TH_PUSH; 49067754Smsmith else 49167754Smsmith th->th_flags &= ~TH_PUSH; 49267754Smsmith 49367754Smsmith switch (changes & SPECIALS_MASK) { 49467754Smsmith case SPECIAL_I: 49567754Smsmith { 49667754Smsmith register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 49767754Smsmith 49867754Smsmith th->th_ack = htonl(ntohl(th->th_ack) + i); 49967754Smsmith th->th_seq = htonl(ntohl(th->th_seq) + i); 50067754Smsmith } 50167754Smsmith break; 50267754Smsmith 50385756Smsmith case SPECIAL_D: 50467754Smsmith th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 50567754Smsmith - cs->cs_hlen); 50667754Smsmith break; 50767754Smsmith 50867754Smsmith default: 50982367Smsmith if (changes & NEW_U) { 51067754Smsmith th->th_flags |= TH_URG; 51199146Siwasaki DECODEU(th->th_urp) 51267754Smsmith } else 51367754Smsmith th->th_flags &= ~TH_URG; 51467754Smsmith if (changes & NEW_W) 51585756Smsmith DECODES(th->th_win) 51667754Smsmith if (changes & NEW_A) 51785756Smsmith DECODEL(th->th_ack) 518115351Snjl if (changes & NEW_S) { 519115351Snjl log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 520115351Snjl *cp, cp[1], cp[2]); 521115351Snjl DECODEL(th->th_seq) 522115351Snjl } 523115351Snjl break; 524115351Snjl } 525115351Snjl if (changes & NEW_I) { 526115351Snjl DECODES(cs->cs_ip.ip_id) 527115351Snjl } else 528115351Snjl cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 529115351Snjl 530115351Snjl log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 531115351Snjl cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 532115351Snjl 533115351Snjl /* 534115351Snjl * At this point, cp points to the first byte of data in the packet. 535115351Snjl * Back up cp by the tcp/ip header length to make room for the 536115351Snjl * reconstructed header (we assume the packet we were handed has enough 537115351Snjl * space to prepend 128 bytes of header). Adjust the length to account 538115351Snjl * for the new header & fill in the IP total length. 53980062Smsmith */ 54067754Smsmith len -= (cp - *bufp); 54167754Smsmith if (len < 0) 54267754Smsmith /* 54367754Smsmith * we must have dropped some characters (crc should detect this but the 54467754Smsmith * old slip framing won't) 54567754Smsmith */ 54667754Smsmith goto bad; 54767754Smsmith 54867754Smsmith *bufp = cp - cs->cs_hlen; 54967754Smsmith len += cs->cs_hlen; 55067754Smsmith cs->cs_ip.ip_len = htons(len); 55167754Smsmith 55267754Smsmith /* recompute the ip header checksum */ 55367754Smsmith cs->cs_ip.ip_sum = 0; 55467754Smsmith bp = (u_short *)&cs->cs_ip; 55567754Smsmith for (changes = 0; hlen > 0; hlen -= 2) 55667754Smsmith changes += *bp++; 55767754Smsmith changes = (changes & 0xffff) + (changes >> 16); 55867754Smsmith changes = (changes & 0xffff) + (changes >> 16); 55967754Smsmith cs->cs_ip.ip_sum = ~changes; 56083174Smsmith 56167754Smsmith /* And copy the result into our buffer */ 56267754Smsmith memcpy(*bufp, &cs->cs_ip, cs->cs_hlen); 56367754Smsmith 56467754Smsmith return (len); 56591116Smsmithbad: 56667754Smsmith comp->flags |= SLF_TOSS; 56767754Smsmith slstat->sls_errorin++; 56867754Smsmith return (0); 56999679Siwasaki} 57067754Smsmith 57167754Smsmithint 57267754Smsmithsl_Show(struct cmdargs const *arg) 57384491Smsmith{ 57484491Smsmith prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 57567754Smsmith prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 57667754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 57791116Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 57867754Smsmith prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 57967754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 58067754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 58167754Smsmith prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 58299679Siwasaki arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 58367754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 58467754Smsmith prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 58567754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 58667754Smsmith arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 58767754Smsmith return 0; 58867754Smsmith} 58967754Smsmith