From 1aea408cafea7c57cd1e0fb73e334f34b5c395f9 Mon Sep 17 00:00:00 2001 From: Peter Wemm Date: Tue, 31 Oct 1995 20:51:24 +0000 Subject: [PATCH] Remove the old pppcompress files (btw: these look net-2 derived) commit merge for bsd_comp.c - I missed this with a *ppp* wildcard. --- sys/net/bsd_comp.c | 10 +- sys/net/pppcompress.c | 594 ------------------------------------------ sys/net/pppcompress.h | 178 ------------- 3 files changed, 9 insertions(+), 773 deletions(-) delete mode 100644 sys/net/pppcompress.c delete mode 100644 sys/net/pppcompress.h diff --git a/sys/net/bsd_comp.c b/sys/net/bsd_comp.c index dab34ba50b51..4e438b533149 100644 --- a/sys/net/bsd_comp.c +++ b/sys/net/bsd_comp.c @@ -40,11 +40,13 @@ /* * This version is for use with mbufs on BSD-derived systems. * - * $Id: bsd_comp.c,v 1.1.2.1 1995/10/31 20:07:32 peter Exp $ + * from: Id: bsd-comp.c,v 1.11 1995/07/04 03:35:11 paulus Exp + * $Id$ */ #include #include +#include #include #include #include @@ -129,6 +131,12 @@ struct bsd_db { #define BSD_OVHD 2 /* BSD compress overhead/packet */ #define BSD_INIT_BITS BSD_MIN_BITS +static void bsd_clear __P((struct bsd_db *db)); +static int bsd_check __P((struct bsd_db *db)); +static void *bsd_alloc __P((u_char *options, int opt_len, int decomp)); +static int bsd_init __P((struct bsd_db *db, u_char *options, int opt_len, + int unit, int hdrlen, int mru, int debug, + int decomp)); static void *bsd_comp_alloc __P((u_char *options, int opt_len)); static void *bsd_decomp_alloc __P((u_char *options, int opt_len)); static void bsd_free __P((void *state)); diff --git a/sys/net/pppcompress.c b/sys/net/pppcompress.c deleted file mode 100644 index 5485b0fbb4cf..000000000000 --- a/sys/net/pppcompress.c +++ /dev/null @@ -1,594 +0,0 @@ -/*- - * Copyright (c) 1989 The Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * @(#)slcompress.c 7.7 (Berkeley) 5/7/91 - */ - -/* - * Routines to compress and uncompess tcp packets (for transmission - * over low speed serial lines. - * - * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: - * - Initial distribution. - * - * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au, - * so that the entire packet being decompressed doesn't have - * to be in contiguous memory (just the compressed header). - * - * $Id: pppcompress.c,v 1.3 1994/11/01 09:03:20 pst Exp $ - */ - -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include - -#include - -#ifndef SL_NO_STATS -#define INCR(counter) ++comp->counter; -#else -#define INCR(counter) -#endif - -#define BCMP(p1, p2, n) bcmp((char *)(p1), (char *)(p2), (int)(n)) -#define BCOPY(p1, p2, n) bcopy((char *)(p1), (char *)(p2), (int)(n)) -#ifndef KERNEL -#define ovbcopy bcopy -#endif - - -void -sl_compress_init(comp) - struct slcompress *comp; -{ - register u_int i; - register struct cstate *tstate = comp->tstate; - - bzero((char *)comp, sizeof(*comp)); - for (i = MAX_STATES - 1; i > 0; --i) { - tstate[i].cs_id = i; - tstate[i].cs_next = &tstate[i - 1]; - } - tstate[0].cs_next = &tstate[MAX_STATES - 1]; - tstate[0].cs_id = 0; - comp->last_cs = &tstate[0]; - comp->last_recv = 255; - comp->last_xmit = 255; - comp->flags = SLF_TOSS; -} - - -/* - * Like sl_compress_init, but we get to specify the maximum connection - * ID to use on transmission. - */ -void -sl_compress_setup(comp, max_state) - struct slcompress *comp; - int max_state; -{ - register u_int i; - register struct cstate *tstate = comp->tstate; - - if ((unsigned) max_state > MAX_STATES - 1) - max_state = MAX_STATES - 1; - bzero((char *)comp, sizeof(*comp)); - for (i = max_state; i > 0; --i) { - tstate[i].cs_id = i; - tstate[i].cs_next = &tstate[i - 1]; - } - tstate[0].cs_next = &tstate[max_state]; - tstate[0].cs_id = 0; - comp->last_cs = &tstate[0]; - comp->last_recv = 255; - comp->last_xmit = 255; - comp->flags = SLF_TOSS; -} - - -/* ENCODE encodes a number that is known to be non-zero. ENCODEZ - * checks for zero (since zero has to be encoded in the long, 3 byte - * form). - */ -#define ENCODE(n) { \ - if ((u_short)(n) >= 256) { \ - *cp++ = 0; \ - cp[1] = (n); \ - cp[0] = (n) >> 8; \ - cp += 2; \ - } else { \ - *cp++ = (n); \ - } \ -} -#define ENCODEZ(n) { \ - if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ - *cp++ = 0; \ - cp[1] = (n); \ - cp[0] = (n) >> 8; \ - cp += 2; \ - } else { \ - *cp++ = (n); \ - } \ -} - -#define DECODEL(f) { \ - if (*cp == 0) {\ - (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ - cp += 3; \ - } else { \ - (f) = htonl(ntohl(f) + (u_long)*cp++); \ - } \ -} - -#define DECODES(f) { \ - if (*cp == 0) {\ - (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ - cp += 3; \ - } else { \ - (f) = htons(ntohs(f) + (u_long)*cp++); \ - } \ -} - -#define DECODEU(f) { \ - if (*cp == 0) {\ - (f) = htons((cp[1] << 8) | cp[2]); \ - cp += 3; \ - } else { \ - (f) = htons((u_long)*cp++); \ - } \ -} - - -u_char -sl_compress_tcp(m, ip, comp, compress_cid) - struct mbuf *m; - register struct ip *ip; - struct slcompress *comp; - int compress_cid; -{ - register struct cstate *cs = comp->last_cs->cs_next; - register u_int hlen = ip->ip_hl; - register struct tcphdr *oth; - register struct tcphdr *th; - register u_int deltaS, deltaA; - register u_int changes = 0; - u_char new_seq[16]; - register u_char *cp = new_seq; - - /* - * Bail if this is an IP fragment or if the TCP packet isn't - * `compressible' (i.e., ACK isn't set or some other control bit is - * set). (We assume that the caller has already made sure the - * packet is IP proto TCP). - */ - if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) - return (TYPE_IP); - - th = (struct tcphdr *)&((int *)ip)[hlen]; - if ((th->th_flags & (TH_SYN|TH_FIN|TH_RST|TH_ACK)) != TH_ACK) - return (TYPE_IP); - /* - * Packet is compressible -- we're going to send either a - * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need - * to locate (or create) the connection state. Special case the - * most recently used connection since it's most likely to be used - * again & we don't have to do any reordering if it's used. - */ - INCR(sls_packets) - if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || - ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || - *(int *)th != ((int *)&cs->cs_ip)[cs->cs_ip.ip_hl]) { - /* - * Wasn't the first -- search for it. - * - * States are kept in a circularly linked list with - * last_cs pointing to the end of the list. The - * list is kept in lru order by moving a state to the - * head of the list whenever it is referenced. Since - * the list is short and, empirically, the connection - * we want is almost always near the front, we locate - * states via linear search. If we don't find a state - * for the datagram, the oldest state is (re-)used. - */ - register struct cstate *lcs; - register struct cstate *lastcs = comp->last_cs; - - do { - lcs = cs; cs = cs->cs_next; - INCR(sls_searches) - if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr - && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr - && *(int *)th == ((int *)&cs->cs_ip)[cs->cs_ip.ip_hl]) - goto found; - } while (cs != lastcs); - - /* - * Didn't find it -- re-use oldest cstate. Send an - * uncompressed packet that tells the other side what - * connection number we're using for this conversation. - * Note that since the state list is circular, the oldest - * state points to the newest and we only need to set - * last_cs to update the lru linkage. - */ - INCR(sls_misses) - comp->last_cs = lcs; - hlen += th->th_off; - hlen <<= 2; - if (hlen > m->m_len) - return (TYPE_IP); - goto uncompressed; - - found: - /* - * Found it -- move to the front on the connection list. - */ - if (cs == lastcs) - comp->last_cs = lcs; - else { - lcs->cs_next = cs->cs_next; - cs->cs_next = lastcs->cs_next; - lastcs->cs_next = cs; - } - } - - /* - * Make sure that only what we expect to change changed. The first - * line of the `if' checks the IP protocol version, header length & - * type of service. The 2nd line checks the "Don't fragment" bit. - * The 3rd line checks the time-to-live and protocol (the protocol - * check is unnecessary but costless). The 4th line checks the TCP - * header length. The 5th line checks IP options, if any. The 6th - * line checks TCP options, if any. If any of these things are - * different between the previous & current datagram, we send the - * current datagram `uncompressed'. - */ - oth = (struct tcphdr *)&((int *)&cs->cs_ip)[hlen]; - deltaS = hlen; - hlen += th->th_off; - hlen <<= 2; - if (hlen > m->m_len) - return (TYPE_IP); - - if (((u_short *)ip)[0] != ((u_short *)&cs->cs_ip)[0] || - ((u_short *)ip)[3] != ((u_short *)&cs->cs_ip)[3] || - ((u_short *)ip)[4] != ((u_short *)&cs->cs_ip)[4] || - th->th_off != oth->th_off || - (deltaS > 5 && - BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || - (th->th_off > 5 && - BCMP(th + 1, oth + 1, (th->th_off - 5) << 2))) - goto uncompressed; - - /* - * Figure out which of the changing fields changed. The - * receiver expects changes in the order: urgent, window, - * ack, seq (the order minimizes the number of temporaries - * needed in this section of code). - */ - if (th->th_flags & TH_URG) { - deltaS = ntohs(th->th_urp); - ENCODEZ(deltaS); - changes |= NEW_U; - } else if (th->th_urp != oth->th_urp) - /* argh! URG not set but urp changed -- a sensible - * implementation should never do this but RFC793 - * doesn't prohibit the change so we have to deal - * with it. */ - goto uncompressed; - - if (deltaS = (u_short)(ntohs(th->th_win) - ntohs(oth->th_win))) { - ENCODE(deltaS); - changes |= NEW_W; - } - - if (deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack)) { - if (deltaA > 0xffff) - goto uncompressed; - ENCODE(deltaA); - changes |= NEW_A; - } - - if (deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq)) { - if (deltaS > 0xffff) - goto uncompressed; - ENCODE(deltaS); - changes |= NEW_S; - } - - switch(changes) { - - case 0: - /* - * Nothing changed. If this packet contains data and the - * last one didn't, this is probably a data packet following - * an ack (normal on an interactive connection) and we send - * it compressed. Otherwise it's probably a retransmit, - * retransmitted ack or window probe. Send it uncompressed - * in case the other side missed the compressed version. - */ - if (ip->ip_len != cs->cs_ip.ip_len && - ntohs(cs->cs_ip.ip_len) == hlen) - break; - - /* (fall through) */ - - case SPECIAL_I: - case SPECIAL_D: - /* - * actual changes match one of our special case encodings -- - * send packet uncompressed. - */ - goto uncompressed; - - case NEW_S|NEW_A: - if (deltaS == deltaA && - deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { - /* special case for echoed terminal traffic */ - changes = SPECIAL_I; - cp = new_seq; - } - break; - - case NEW_S: - if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { - /* special case for data xfer */ - changes = SPECIAL_D; - cp = new_seq; - } - break; - } - - deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); - if (deltaS != 1) { - ENCODEZ(deltaS); - changes |= NEW_I; - } - if (th->th_flags & TH_PUSH) - changes |= TCP_PUSH_BIT; - /* - * Grab the cksum before we overwrite it below. Then update our - * state with this packet's header. - */ - deltaA = ntohs(th->th_sum); - BCOPY(ip, &cs->cs_ip, hlen); - - /* - * We want to use the original packet as our compressed packet. - * (cp - new_seq) is the number of bytes we need for compressed - * sequence numbers. In addition we need one byte for the change - * mask, one for the connection id and two for the tcp checksum. - * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how - * many bytes of the original packet to toss so subtract the two to - * get the new packet size. - */ - deltaS = cp - new_seq; - cp = (u_char *)ip; - if (compress_cid == 0 || comp->last_xmit != cs->cs_id) { - comp->last_xmit = cs->cs_id; - hlen -= deltaS + 4; - cp += hlen; - *cp++ = changes | NEW_C; - *cp++ = cs->cs_id; - } else { - hlen -= deltaS + 3; - cp += hlen; - *cp++ = changes; - } - m->m_len -= hlen; - m->m_data += hlen; - *cp++ = deltaA >> 8; - *cp++ = deltaA; - BCOPY(new_seq, cp, deltaS); - INCR(sls_compressed) - return (TYPE_COMPRESSED_TCP); - - /* - * Update connection state cs & send uncompressed packet ('uncompressed' - * means a regular ip/tcp packet but with the 'conversation id' we hope - * to use on future compressed packets in the protocol field). - */ -uncompressed: - BCOPY(ip, &cs->cs_ip, hlen); - ip->ip_p = cs->cs_id; - comp->last_xmit = cs->cs_id; - return (TYPE_UNCOMPRESSED_TCP); -} - - -int -sl_uncompress_tcp(bufp, len, type, comp) - u_char **bufp; - int len; - u_int type; - struct slcompress *comp; -{ - return sl_uncompress_tcp_part(bufp, len, len, type, comp); -} - - -/* - * Uncompress a packet of total length total_len. The first buflen - * bytes are at *bufp; this must include the entire (compressed or - * uncompressed) TCP/IP header. In addition, there must be enough - * clear space before *bufp to build a full-length TCP/IP header. - */ -int -sl_uncompress_tcp_part(bufp, buflen, total_len, type, comp) - u_char **bufp; - int buflen, total_len; - u_int type; - struct slcompress *comp; -{ - register u_char *cp; - register u_int hlen, changes; - register struct tcphdr *th; - register struct cstate *cs; - register struct ip *ip; - - switch (type) { - - case TYPE_UNCOMPRESSED_TCP: - ip = (struct ip *) *bufp; - if (ip->ip_p >= MAX_STATES) - goto bad; - cs = &comp->rstate[comp->last_recv = ip->ip_p]; - comp->flags &=~ SLF_TOSS; - ip->ip_p = IPPROTO_TCP; - hlen = ip->ip_hl; - hlen += ((struct tcphdr *)&((int *)ip)[hlen])->th_off; - hlen <<= 2; - BCOPY(ip, &cs->cs_ip, hlen); - cs->cs_ip.ip_sum = 0; - cs->cs_hlen = hlen; - INCR(sls_uncompressedin) - return (total_len); - - default: - goto bad; - - case TYPE_COMPRESSED_TCP: - break; - } - /* We've got a compressed packet. */ - INCR(sls_compressedin) - cp = *bufp; - changes = *cp++; - if (changes & NEW_C) { - /* Make sure the state index is in range, then grab the state. - * If we have a good state index, clear the 'discard' flag. */ - if (*cp >= MAX_STATES) - goto bad; - - comp->flags &=~ SLF_TOSS; - comp->last_recv = *cp++; - } else { - /* this packet has an implicit state index. If we've - * had a line error since the last time we got an - * explicit state index, we have to toss the packet. */ - if (comp->flags & SLF_TOSS) { - INCR(sls_tossed) - return (0); - } - } - cs = &comp->rstate[comp->last_recv]; - hlen = cs->cs_ip.ip_hl << 2; - th = (struct tcphdr *)&((u_char *)&cs->cs_ip)[hlen]; - th->th_sum = htons((*cp << 8) | cp[1]); - cp += 2; - if (changes & TCP_PUSH_BIT) - th->th_flags |= TH_PUSH; - else - th->th_flags &=~ TH_PUSH; - - switch (changes & SPECIALS_MASK) { - case SPECIAL_I: - { - register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; - th->th_ack = htonl(ntohl(th->th_ack) + i); - th->th_seq = htonl(ntohl(th->th_seq) + i); - } - break; - - case SPECIAL_D: - th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) - - cs->cs_hlen); - break; - - default: - if (changes & NEW_U) { - th->th_flags |= TH_URG; - DECODEU(th->th_urp) - } else - th->th_flags &=~ TH_URG; - if (changes & NEW_W) - DECODES(th->th_win) - if (changes & NEW_A) - DECODEL(th->th_ack) - if (changes & NEW_S) - DECODEL(th->th_seq) - break; - } - if (changes & NEW_I) { - DECODES(cs->cs_ip.ip_id) - } else - cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); - - /* - * At this point, cp points to the first byte of data in the - * packet. If we're not aligned on a 4-byte boundary, copy the - * data down so the ip & tcp headers will be aligned. Then back up - * cp by the tcp/ip header length to make room for the reconstructed - * header (we assume the packet we were handed has enough space to - * prepend 128 bytes of header). Adjust the length to account for - * the new header & fill in the IP total length. - */ - buflen -= (cp - *bufp); - total_len -= (cp - *bufp); - if (buflen < 0) - /* we must have dropped some characters (crc should detect - * this but the old slip framing won't) */ - goto bad; - - if ((int)cp & 3) { - if (buflen > 0) - (void) ovbcopy(cp, (caddr_t)((int)cp &~ 3), buflen); - cp = (u_char *)((int)cp &~ 3); - } - cp -= cs->cs_hlen; - total_len += cs->cs_hlen; - cs->cs_ip.ip_len = htons(total_len); - BCOPY(&cs->cs_ip, cp, cs->cs_hlen); - *bufp = cp; - - /* recompute the ip header checksum */ - { - register u_short *bp = (u_short *)cp; - for (changes = 0; hlen > 0; hlen -= 2) - changes += *bp++; - changes = (changes & 0xffff) + (changes >> 16); - changes = (changes & 0xffff) + (changes >> 16); - ((struct ip *)cp)->ip_sum = ~ changes; - } - return (total_len); -bad: - comp->flags |= SLF_TOSS; - INCR(sls_errorin) - return (0); -} diff --git a/sys/net/pppcompress.h b/sys/net/pppcompress.h deleted file mode 100644 index 93f3e510211d..000000000000 --- a/sys/net/pppcompress.h +++ /dev/null @@ -1,178 +0,0 @@ -/* - * Definitions for tcp compression routines. - * - * Copyright (c) 1989 Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: - * - Initial distribution. - * - * Paul Mackerras (paulus@cs.anu.edu.au), June 1993: - * - added sl_uncompress_tcp_part. - * - * From: slcompress.h 7.4 90/06/28 - * $Id: pppcompress.h,v 1.2 1994/09/23 00:13:22 wollman Exp $ - */ - -#ifndef _NET_PPPCOMPRESS_H_ -#define _NET_PPPCOMPRESS_H_ - -#define MAX_STATES 16 /* must be > 2 and < 256 */ -#define MAX_HDR MLEN /* XXX 4bsd-ism: should really be 128 */ - -/* - * Compressed packet format: - * - * The first octet contains the packet type (top 3 bits), TCP - * 'push' bit, and flags that indicate which of the 4 TCP sequence - * numbers have changed (bottom 5 bits). The next octet is a - * conversation number that associates a saved IP/TCP header with - * the compressed packet. The next two octets are the TCP checksum - * from the original datagram. The next 0 to 15 octets are - * sequence number changes, one change per bit set in the header - * (there may be no changes and there are two special cases where - * the receiver implicitly knows what changed -- see below). - * - * There are 5 numbers which can change (they are always inserted - * in the following order): TCP urgent pointer, window, - * acknowlegement, sequence number and IP ID. (The urgent pointer - * is different from the others in that its value is sent, not the - * change in value.) Since typical use of SLIP links is biased - * toward small packets (see comments on MTU/MSS below), changes - * use a variable length coding with one octet for numbers in the - * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the - * range 256 - 65535 or 0. (If the change in sequence number or - * ack is more than 65535, an uncompressed packet is sent.) - */ - -/* - * Packet types (must not conflict with IP protocol version) - * - * The top nibble of the first octet is the packet type. There are - * three possible types: IP (not proto TCP or tcp with one of the - * control flags set); uncompressed TCP (a normal IP/TCP packet but - * with the 8-bit protocol field replaced by an 8-bit connection id -- - * this type of packet syncs the sender & receiver); and compressed - * TCP (described above). - * - * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and - * is logically part of the 4-bit "changes" field that follows. Top - * three bits are actual packet type. For backward compatibility - * and in the interest of conserving bits, numbers are chosen so the - * IP protocol version number (4) which normally appears in this nibble - * means "IP packet". - */ - -/* packet types */ -#define TYPE_IP 0x40 -#define TYPE_UNCOMPRESSED_TCP 0x70 -#define TYPE_COMPRESSED_TCP 0x80 -#define TYPE_ERROR 0x00 - -/* Bits in first octet of compressed packet */ -#define NEW_C 0x40 /* flag bits for what changed in a packet */ -#define NEW_I 0x20 -#define NEW_S 0x08 -#define NEW_A 0x04 -#define NEW_W 0x02 -#define NEW_U 0x01 - -/* reserved, special-case values of above */ -#define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */ -#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */ -#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U) - -#define TCP_PUSH_BIT 0x10 - - -/* - * "state" data for each active tcp conversation on the wire. This is - * basically a copy of the entire IP/TCP header from the last packet - * we saw from the conversation together with a small identifier - * the transmit & receive ends of the line use to locate saved header. - */ -struct cstate { - struct cstate *cs_next; /* next most recently used cstate (xmit only) */ - u_short cs_hlen; /* size of hdr (receive only) */ - u_char cs_id; /* connection # associated with this state */ - u_char cs_filler; - union { - char csu_hdr[MAX_HDR]; - struct ip csu_ip; /* ip/tcp hdr from most recent packet */ - } slcs_u; -}; -#define cs_ip slcs_u.csu_ip -#define cs_hdr slcs_u.csu_hdr - -/* - * all the state data for one serial line (we need one of these - * per line). - */ -#define slcompress pppcompress - -struct slcompress { - struct cstate *last_cs; /* most recently used tstate */ - u_char last_recv; /* last rcvd conn. id */ - u_char last_xmit; /* last sent conn. id */ - u_short flags; -#ifndef SL_NO_STATS - int sls_packets; /* outbound packets */ - int sls_compressed; /* outbound compressed packets */ - int sls_searches; /* searches for connection state */ - int sls_misses; /* times couldn't find conn. state */ - int sls_uncompressedin; /* inbound uncompressed packets */ - int sls_compressedin; /* inbound compressed packets */ - int sls_errorin; /* inbound unknown type packets */ - int sls_tossed; /* inbound packets tossed because of error */ -#endif - struct cstate tstate[MAX_STATES]; /* xmit connection states */ - struct cstate rstate[MAX_STATES]; /* receive connection states */ -}; -/* flag values */ -#define SLF_TOSS 1 /* tossing rcvd frames because of input err */ - -#define sl_compress_init ppp_compress_init -#define sl_compress_setup ppp_compress_setup -#define sl_compress_tcp ppp_compress_tcp -#define sl_uncompress_tcp ppp_uncompress_tcp -#define sl_uncompress_tcp_part ppp_uncompress_tcp_part - -extern void sl_compress_init __P((struct slcompress *)); -extern void sl_compress_setup __P((struct slcompress *, int maxslot)); -extern u_char sl_compress_tcp __P((struct mbuf *m, struct ip *ip, - struct slcompress *, int comp_cid_flag)); -extern int sl_uncompress_tcp __P((u_char **bufp, int len, u_int type, - struct slcompress *)); -extern int sl_uncompress_tcp_part __P((u_char **bufp, int buflen, - int total_len, u_int type, - struct slcompress *)); - -#endif /* _NET_PPPCOMPRESS_H_ */