633 lines
18 KiB
Text
633 lines
18 KiB
Text
$NetBSD: patch-at,v 1.1.1.1 1999/10/08 04:34:43 dbj Exp $
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--- /dev/null Sat Sep 18 04:00:15 1999
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+++ netbsd-1.4/slcompress.c Sat Sep 18 04:06:38 1999
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@@ -0,0 +1,628 @@
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+/* NetBSD: slcompress.c,v 1.20 1999/03/13 14:09:46 drochner Exp */
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+/* Id: slcompress.c,v 1.3 1996/05/24 07:04:47 paulus Exp */
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+
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+/*
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+ * Copyright (c) 1989, 1993, 1994
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+ * The Regents of the University of California. All rights reserved.
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+ *
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+ * Redistribution and use in source and binary forms, with or without
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+ * modification, are permitted provided that the following conditions
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+ * are met:
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+ * 1. Redistributions of source code must retain the above copyright
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+ * notice, this list of conditions and the following disclaimer.
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+ * 2. Redistributions in binary form must reproduce the above copyright
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+ * notice, this list of conditions and the following disclaimer in the
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+ * documentation and/or other materials provided with the distribution.
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+ * 3. All advertising materials mentioning features or use of this software
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+ * must display the following acknowledgement:
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+ * This product includes software developed by the University of
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+ * California, Berkeley and its contributors.
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+ * 4. Neither the name of the University nor the names of its contributors
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+ * may be used to endorse or promote products derived from this software
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+ * without specific prior written permission.
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+ *
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+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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+ * SUCH DAMAGE.
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+ *
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+ * @(#)slcompress.c 8.2 (Berkeley) 4/16/94
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+ */
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+
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+/*
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+ * Routines to compress and uncompess tcp packets (for transmission
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+ * over low speed serial lines.
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+ *
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+ * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
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+ * - Initial distribution.
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+ */
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+
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+#include <sys/param.h>
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+#include <sys/mbuf.h>
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+#include <sys/systm.h>
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+
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+#include <netinet/in.h>
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+#include <netinet/in_systm.h>
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+#include <netinet/ip.h>
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+#include <netinet/tcp.h>
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+
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+#include <net/slcompress.h>
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+
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+#ifndef SL_NO_STATS
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+#define INCR(counter) ++comp->counter;
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+#else
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+#define INCR(counter)
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+#endif
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+
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+#define BCMP(p1, p2, n) bcmp((char *)(p1), (char *)(p2), (int)(n))
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+#define BCOPY(p1, p2, n) bcopy((char *)(p1), (char *)(p2), (int)(n))
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+
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+
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+void
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+sl_compress_init(comp)
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+ struct slcompress *comp;
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+{
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+ register u_int i;
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+ register struct cstate *tstate = comp->tstate;
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+
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+ bzero((char *)comp, sizeof(*comp));
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+ for (i = MAX_STATES - 1; i > 0; --i) {
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+ tstate[i].cs_id = i;
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+ tstate[i].cs_next = &tstate[i - 1];
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+ }
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+ tstate[0].cs_next = &tstate[MAX_STATES - 1];
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+ tstate[0].cs_id = 0;
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+ comp->last_cs = &tstate[0];
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+ comp->last_recv = 255;
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+ comp->last_xmit = 255;
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+ comp->flags = SLF_TOSS;
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+}
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+
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+
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+/*
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+ * Like sl_compress_init, but we get to specify the maximum connection
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+ * ID to use on transmission.
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+ */
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+void
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+sl_compress_setup(comp, max_state)
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+ struct slcompress *comp;
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+ int max_state;
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+{
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+ register u_int i;
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+ register struct cstate *tstate = comp->tstate;
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+
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+ if (max_state == -1) {
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+ max_state = MAX_STATES - 1;
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+ bzero((char *)comp, sizeof(*comp));
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+ } else {
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+ /* Don't reset statistics */
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+ bzero((char *)comp->tstate, sizeof(comp->tstate));
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+ bzero((char *)comp->rstate, sizeof(comp->rstate));
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+ }
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+ for (i = max_state; i > 0; --i) {
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+ tstate[i].cs_id = i;
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+ tstate[i].cs_next = &tstate[i - 1];
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+ }
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+ tstate[0].cs_next = &tstate[max_state];
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+ tstate[0].cs_id = 0;
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+ comp->last_cs = &tstate[0];
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+ comp->last_recv = 255;
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+ comp->last_xmit = 255;
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+ comp->flags = SLF_TOSS;
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+}
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+
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+
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+/* ENCODE encodes a number that is known to be non-zero. ENCODEZ
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+ * checks for zero (since zero has to be encoded in the long, 3 byte
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+ * form).
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+ */
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+#define ENCODE(n) { \
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+ if ((u_int16_t)(n) >= 256) { \
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+ *cp++ = 0; \
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+ cp[1] = (n); \
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+ cp[0] = (n) >> 8; \
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+ cp += 2; \
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+ } else { \
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+ *cp++ = (n); \
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+ } \
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+}
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+#define ENCODEZ(n) { \
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+ if ((u_int16_t)(n) >= 256 || (u_int16_t)(n) == 0) { \
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+ *cp++ = 0; \
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+ cp[1] = (n); \
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+ cp[0] = (n) >> 8; \
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+ cp += 2; \
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+ } else { \
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+ *cp++ = (n); \
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+ } \
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+}
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+
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+#define DECODEL(f) { \
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+ if (*cp == 0) {\
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+ (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \
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+ cp += 3; \
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+ } else { \
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+ (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \
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+ } \
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+}
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+
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+#define DECODES(f) { \
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+ if (*cp == 0) {\
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+ (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \
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+ cp += 3; \
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+ } else { \
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+ (f) = htons(ntohs(f) + (u_int32_t)*cp++); \
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+ } \
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+}
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+
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+#define DECODEU(f) { \
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+ if (*cp == 0) {\
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+ (f) = htons((cp[1] << 8) | cp[2]); \
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+ cp += 3; \
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+ } else { \
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+ (f) = htons((u_int32_t)*cp++); \
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+ } \
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+}
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+
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+u_int
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+sl_compress_tcp(m, ip, comp, compress_cid)
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+ struct mbuf *m;
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+ register struct ip *ip;
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+ struct slcompress *comp;
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+ int compress_cid;
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+{
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+ register struct cstate *cs = comp->last_cs->cs_next;
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+ register u_int hlen = ip->ip_hl;
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+ register struct tcphdr *oth;
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+ register struct tcphdr *th;
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+ register u_int deltaS, deltaA;
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+ register u_int changes = 0;
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+ u_char new_seq[16];
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+ register u_char *cp = new_seq;
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+
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+ /*
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+ * Bail if this is an IP fragment or if the TCP packet isn't
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+ * `compressible' (i.e., ACK isn't set or some other control bit is
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+ * set). (We assume that the caller has already made sure the
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+ * packet is IP proto TCP).
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+ */
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+ if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40)
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+ return (TYPE_IP);
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+
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+ th = (struct tcphdr *)&((int32_t *)ip)[hlen];
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+ if ((th->th_flags & (TH_SYN|TH_FIN|TH_RST|TH_ACK)) != TH_ACK)
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+ return (TYPE_IP);
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+ /*
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+ * Packet is compressible -- we're going to send either a
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+ * COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
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+ * to locate (or create) the connection state. Special case the
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+ * most recently used connection since it's most likely to be used
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+ * again & we don't have to do any reordering if it's used.
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+ */
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+ INCR(sls_packets)
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+ if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr ||
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+ ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr ||
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+ *(int32_t *)th != ((int32_t *)&cs->cs_ip)[cs->cs_ip.ip_hl]) {
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+ /*
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+ * Wasn't the first -- search for it.
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+ *
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+ * States are kept in a circularly linked list with
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+ * last_cs pointing to the end of the list. The
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+ * list is kept in lru order by moving a state to the
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+ * head of the list whenever it is referenced. Since
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+ * the list is short and, empirically, the connection
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+ * we want is almost always near the front, we locate
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+ * states via linear search. If we don't find a state
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+ * for the datagram, the oldest state is (re-)used.
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+ */
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+ register struct cstate *lcs;
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+ register struct cstate *lastcs = comp->last_cs;
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+
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+ do {
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+ lcs = cs; cs = cs->cs_next;
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+ INCR(sls_searches)
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+ if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr
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+ && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr
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+ && *(int32_t *)th ==
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+ ((int32_t *)&cs->cs_ip)[cs->cs_ip.ip_hl])
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+ goto found;
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+ } while (cs != lastcs);
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+
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+ /*
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+ * Didn't find it -- re-use oldest cstate. Send an
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+ * uncompressed packet that tells the other side what
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+ * connection number we're using for this conversation.
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+ * Note that since the state list is circular, the oldest
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+ * state points to the newest and we only need to set
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+ * last_cs to update the lru linkage.
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+ */
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+ INCR(sls_misses)
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+ comp->last_cs = lcs;
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+ hlen += th->th_off;
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+ hlen <<= 2;
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+ if (hlen > m->m_len)
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+ return (TYPE_IP);
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+ goto uncompressed;
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+
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+ found:
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+ /*
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+ * Found it -- move to the front on the connection list.
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+ */
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+ if (cs == lastcs)
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+ comp->last_cs = lcs;
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+ else {
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+ lcs->cs_next = cs->cs_next;
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+ cs->cs_next = lastcs->cs_next;
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+ lastcs->cs_next = cs;
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+ }
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+ }
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+
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+ /*
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+ * Make sure that only what we expect to change changed. The first
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+ * line of the `if' checks the IP protocol version, header length &
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+ * type of service. The 2nd line checks the "Don't fragment" bit.
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+ * The 3rd line checks the time-to-live and protocol (the protocol
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+ * check is unnecessary but costless). The 4th line checks the TCP
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+ * header length. The 5th line checks IP options, if any. The 6th
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+ * line checks TCP options, if any. If any of these things are
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+ * different between the previous & current datagram, we send the
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+ * current datagram `uncompressed'.
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+ */
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+ oth = (struct tcphdr *)&((int32_t *)&cs->cs_ip)[hlen];
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+ deltaS = hlen;
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+ hlen += th->th_off;
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+ hlen <<= 2;
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+ if (hlen > m->m_len)
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+ return (TYPE_IP);
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+
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+ if (((u_int16_t *)ip)[0] != ((u_int16_t *)&cs->cs_ip)[0] ||
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+ ((u_int16_t *)ip)[3] != ((u_int16_t *)&cs->cs_ip)[3] ||
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+ ((u_int16_t *)ip)[4] != ((u_int16_t *)&cs->cs_ip)[4] ||
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+ th->th_off != oth->th_off ||
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+ (deltaS > 5 &&
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+ BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) ||
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+ (th->th_off > 5 &&
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+ BCMP(th + 1, oth + 1, (th->th_off - 5) << 2)))
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+ goto uncompressed;
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+
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+ /*
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+ * Figure out which of the changing fields changed. The
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+ * receiver expects changes in the order: urgent, window,
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+ * ack, seq (the order minimizes the number of temporaries
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+ * needed in this section of code).
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+ */
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+ if (th->th_flags & TH_URG) {
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+ deltaS = ntohs(th->th_urp);
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+ ENCODEZ(deltaS);
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+ changes |= NEW_U;
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+ } else if (th->th_urp != oth->th_urp)
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+ /* argh! URG not set but urp changed -- a sensible
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+ * implementation should never do this but RFC793
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+ * doesn't prohibit the change so we have to deal
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+ * with it. */
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+ goto uncompressed;
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+
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+ deltaS = (u_int16_t)(ntohs(th->th_win) - ntohs(oth->th_win));
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+ if (deltaS) {
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+ ENCODE(deltaS);
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+ changes |= NEW_W;
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+ }
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+
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+ deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack);
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+ if (deltaA) {
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+ if (deltaA > 0xffff)
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+ goto uncompressed;
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+ ENCODE(deltaA);
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+ changes |= NEW_A;
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+ }
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+
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+ deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq);
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+ if (deltaS) {
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+ if (deltaS > 0xffff)
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+ goto uncompressed;
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+ ENCODE(deltaS);
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+ changes |= NEW_S;
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+ }
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+
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+ switch(changes) {
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+
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+ case 0:
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+ /*
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+ * Nothing changed. If this packet contains data and the
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+ * last one didn't, this is probably a data packet following
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+ * an ack (normal on an interactive connection) and we send
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+ * it compressed. Otherwise it's probably a retransmit,
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+ * retransmitted ack or window probe. Send it uncompressed
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+ * in case the other side missed the compressed version.
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+ */
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+ if (ip->ip_len != cs->cs_ip.ip_len &&
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+ ntohs(cs->cs_ip.ip_len) == hlen)
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+ break;
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+
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+ /* (fall through) */
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+
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+ case SPECIAL_I:
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+ case SPECIAL_D:
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+ /*
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+ * actual changes match one of our special case encodings --
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+ * send packet uncompressed.
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+ */
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+ goto uncompressed;
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+
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+ case NEW_S|NEW_A:
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+ if (deltaS == deltaA &&
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+ deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
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+ /* special case for echoed terminal traffic */
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+ changes = SPECIAL_I;
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+ cp = new_seq;
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+ }
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+ break;
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+
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+ case NEW_S:
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+ if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
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+ /* special case for data xfer */
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+ changes = SPECIAL_D;
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+ cp = new_seq;
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+ }
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+ break;
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+ }
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+
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+ deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id);
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+ if (deltaS != 1) {
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+ ENCODEZ(deltaS);
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+ changes |= NEW_I;
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+ }
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+ if (th->th_flags & TH_PUSH)
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+ changes |= TCP_PUSH_BIT;
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+ /*
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+ * Grab the cksum before we overwrite it below. Then update our
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+ * state with this packet's header.
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+ */
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+ deltaA = ntohs(th->th_sum);
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+ BCOPY(ip, &cs->cs_ip, hlen);
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+
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+ /*
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+ * We want to use the original packet as our compressed packet.
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+ * (cp - new_seq) is the number of bytes we need for compressed
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+ * sequence numbers. In addition we need one byte for the change
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+ * mask, one for the connection id and two for the tcp checksum.
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+ * So, (cp - new_seq) + 4 bytes of header are needed. hlen is how
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+ * many bytes of the original packet to toss so subtract the two to
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+ * get the new packet size.
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+ */
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+ deltaS = cp - new_seq;
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+ cp = (u_char *)ip;
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+ if (compress_cid == 0 || comp->last_xmit != cs->cs_id) {
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+ comp->last_xmit = cs->cs_id;
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+ hlen -= deltaS + 4;
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+ cp += hlen;
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+ *cp++ = changes | NEW_C;
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+ *cp++ = cs->cs_id;
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+ } else {
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+ hlen -= deltaS + 3;
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+ cp += hlen;
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+ *cp++ = changes;
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+ }
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+ m->m_len -= hlen;
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+ m->m_data += hlen;
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+ *cp++ = deltaA >> 8;
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+ *cp++ = deltaA;
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+ BCOPY(new_seq, cp, deltaS);
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+ INCR(sls_compressed)
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+ return (TYPE_COMPRESSED_TCP);
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+
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+ /*
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+ * Update connection state cs & send uncompressed packet ('uncompressed'
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+ * means a regular ip/tcp packet but with the 'conversation id' we hope
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+ * to use on future compressed packets in the protocol field).
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+ */
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+uncompressed:
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+ BCOPY(ip, &cs->cs_ip, hlen);
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+ ip->ip_p = cs->cs_id;
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+ comp->last_xmit = cs->cs_id;
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+ return (TYPE_UNCOMPRESSED_TCP);
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+}
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+
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+
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+int
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+sl_uncompress_tcp(bufp, len, type, comp)
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+ u_char **bufp;
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+ int len;
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+ u_int type;
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+ struct slcompress *comp;
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+{
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+ u_char *hdr, *cp;
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+ int vjlen;
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+ u_int hlen;
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+
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+ cp = bufp? *bufp: NULL;
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+ vjlen = sl_uncompress_tcp_core(cp, len, len, type, comp, &hdr, &hlen);
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+ if (vjlen < 0)
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+ 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 ((long)cp & 3) {
|
|
+ if (len > 0)
|
|
+ memmove((caddr_t)((long)cp &~ 3), cp, len);
|
|
+ cp = (u_char *)((long)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_int16_t *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_int16_t *) &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);
|
|
+}
|