X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ultrix%2Fslcompress.c;fp=ultrix%2Fslcompress.c;h=0000000000000000000000000000000000000000;hb=5dce043b4b7e32d41598442361736a927a5db5e4;hp=971bdeec756053eedb894f54c5bfb0fd50f43309;hpb=3e451dfe42426b51e6ce1d66a3e04de43e055568;p=ppp.git

diff --git a/ultrix/slcompress.c b/ultrix/slcompress.c
deleted file mode 100644
index 971bdee..0000000
--- a/ultrix/slcompress.c
+++ /dev/null
@@ -1,605 +0,0 @@
-/*
- * Routines to compress and uncompess tcp packets (for transmission
- * over low speed serial lines.
- *
- * Copyright (c) 1989 Regents of the University of California.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice and this paragraph are
- * duplicated in all such forms and that any documentation,
- * advertising materials, and other materials related to such
- * distribution and use acknowledge that the software was developed
- * by the University of California, Berkeley.  The name of the
- * University may not be used to endorse or promote products derived
- * from this software without specific prior written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- *
- *	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: slcompress.c,v 1.4 1997/03/04 03:45:18 paulus Exp $
- */
-
-#include "../h/types.h"
-#include "../h/param.h"
-#include "../h/mbuf.h"
-#include "../net/netinet/in.h"
-#include "../net/netinet/in_systm.h"
-#include "../net/netinet/ip.h"
-#include "../net/netinet/tcp.h"
-
-#include "ppp_defs.h"
-#include "slcompress.h"
-
-#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_int
-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_off += 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;
-{
-	u_char *hdr, *cp;
-	int vjlen;
-	u_int hlen;
-
-	cp = bufp? *bufp: NULL;
-	vjlen = sl_uncompress_tcp_core(cp, len, len, type, comp, &hdr, &hlen);
-	if (vjlen < 0)
-		return (0);	/* error */
-	if (vjlen == 0)
-		return (len);	/* was uncompressed already */
-
-	cp += vjlen;
-	len -= vjlen;
-
-	/*
-	 * 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).
-	 */
-	if ((int)cp & 3) {
-		if (len > 0)
-			(void) ovbcopy(cp, (caddr_t)((int)cp &~ 3), len);
-		cp = (u_char *)((int)cp &~ 3);
-	}
-	cp -= hlen;
-	len += hlen;
-	BCOPY(hdr, cp, hlen);
-
-	*bufp = cp;
-	return (len);
-}
-
-/*
- * Uncompress a packet of total length total_len.  The first buflen
- * bytes are at buf; this must include the entire (compressed or
- * uncompressed) TCP/IP header.  This procedure returns the length
- * of the VJ header, with a pointer to the uncompressed IP header
- * in *hdrp and its length in *hlenp.
- */
-int
-sl_uncompress_tcp_core(buf, buflen, total_len, type, comp, hdrp, hlenp)
-	u_char *buf;
-	int buflen, total_len;
-	u_int type;
-	struct slcompress *comp;
-	u_char **hdrp;
-	u_int *hlenp;
-{
-	register u_char *cp;
-	register u_int hlen, changes;
-	register struct tcphdr *th;
-	register struct cstate *cs;
-	register struct ip *ip;
-	register u_short *bp;
-	register u_int vjlen;
-
-	switch (type) {
-
-	case TYPE_UNCOMPRESSED_TCP:
-		ip = (struct ip *) buf;
-		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;
-		/*
-		 * Calculate the size of the TCP/IP header and make sure that
-		 * we don't overflow the space we have available for it.
-		 */
-		hlen = ip->ip_hl << 2;
-		if (hlen + sizeof(struct tcphdr) > buflen)
-			goto bad;
-		hlen += ((struct tcphdr *)&((char *)ip)[hlen])->th_off << 2;
-		if (hlen > MAX_HDR || hlen > buflen)
-			goto bad;
-		BCOPY(ip, &cs->cs_ip, hlen);
-		cs->cs_hlen = hlen;
-		INCR(sls_uncompressedin)
-		*hdrp = (u_char *) &cs->cs_ip;
-		*hlenp = hlen;
-		return (0);
-
-	default:
-		goto bad;
-
-	case TYPE_COMPRESSED_TCP:
-		break;
-	}
-	/* We've got a compressed packet. */
-	INCR(sls_compressedin)
-	cp = buf;
-	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 (-1);
-		}
-	}
-	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.  Fill in the IP total length and update the IP
-	 * header checksum.
-	 */
-	vjlen = cp - buf;
-	buflen -= vjlen;
-	if (buflen < 0)
-		/* we must have dropped some characters (crc should detect
-		 * this but the old slip framing won't) */
-		goto bad;
-
-	total_len += cs->cs_hlen - vjlen;
-	cs->cs_ip.ip_len = htons(total_len);
-
-	/* recompute the ip header checksum */
-	bp = (u_short *) &cs->cs_ip;
-	cs->cs_ip.ip_sum = 0;
-	for (changes = 0; hlen > 0; hlen -= 2)
-		changes += *bp++;
-	changes = (changes & 0xffff) + (changes >> 16);
-	changes = (changes & 0xffff) + (changes >> 16);
-	cs->cs_ip.ip_sum = ~ changes;
-
-	*hdrp = (u_char *) &cs->cs_ip;
-	*hlenp = cs->cs_hlen;
-	return vjlen;
-
-bad:
-	comp->flags |= SLF_TOSS;
-	INCR(sls_errorin)
-	return (-1);
-}