rewrite with better license (explicit "with or without modification").

from openbsd

1 files changed, 325 insertions, 126 deletions

diff --git a/print-gre.c b/print-gre.c
index 3afa0eba..fc090a4a 100644
--- a/print-gre.c
+++ b/print-gre.c
@@ -1,30 +1,44 @@
+/*	$OpenBSD: print-gre.c,v 1.5 2002/09/18 20:40:06 jason Exp $	*/
+
 /*
- * Copyright (c) 1996
- *      The 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, Lawrence Berkeley Laboratory,
- * Berkeley, CA.  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.
+ * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
+ * All rights reserved.
  *
- * Initial contribution from John Hawkinson <jhawk@bbnplanet.com>
+ * 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 Jason L. Wright
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
  *
- * This module implements support for decoding GRE (Generic Routing
- * Encapsulation) tunnels; they're documented in RFC1701 and RFC1702.
- * This code only supports the IP encapsulation thereof.
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+/*
+ * tcpdump filter for GRE - Generic Routing Encapsulation
+ * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE)
  */
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.16 2002-08-01 08:53:08 risso Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.17 2002-09-20 22:42:21 itojun Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -34,137 +48,322 @@ static const char rcsid[] =
 #include <tcpdump-stdinc.h>
 
 #include <stdio.h>
+#include <string.h>
 
 #include "interface.h"
 #include "addrtoname.h"
-#include "extract.h"		/* must come after interface.h */
+#include "extract.h"
 
-struct gre {
-	u_int16_t flags;
-	u_int16_t proto;
-};
+#include "ip.h"
 
-/* RFC 2784 - GRE */
-#define GRE_CP		0x8000	/* Checksum Present */
-#define GRE_VER_MASK	0x0007	/* Version */
+#define	GRE_CP		0x8000		/* checksum present */
+#define	GRE_RP		0x4000		/* routing present */
+#define	GRE_KP		0x2000		/* key present */
+#define	GRE_SP		0x1000		/* sequence# present */
+#define	GRE_sP		0x0800		/* source routing */
+#define	GRE_RECRS	0x0700		/* recursion count */
+#define	GRE_AP		0x0080		/* acknowledgment# present */
+#define	GRE_VERS	0x0007		/* protocol version */
 
-/* RFC 2890 - Key and Sequence extensions to GRE */
-#define GRE_KP		0x2000	/* Key Present */
-#define GRE_SP		0x1000	/* Sequence Present */
+#define	GREPROTO_IP	0x0800		/* IP */
+#define	GREPROTO_PPP	0x880b		/* PPTP */
 
-/* Legacy from RFC 1700 */
-#define GRE_RP		0x4000	/* Routing Present */
-#define GRE_sP		0x0800	/* strict source route present */
-#define GRE_RECUR_MASK	0x0700  /* Recursion Control */
-#define GRE_RECUR_SHIFT	8
+/* source route entry types */
+#define	GRESRE_IP	0x0800		/* IP */
+#define	GRESRE_ASN	0xfffe		/* ASN */
 
-#define GRE_COP		(GRE_RP|GRE_CP)	/* Checksum & Offset Present */
+void gre_print_0(const u_char *, u_int);
+void gre_print_1(const u_char *, u_int);
+void gre_sre_print(u_int16_t, u_int8_t, u_int8_t, const u_char *, u_int);
+void gre_sre_ip_print(u_int8_t, u_int8_t, const u_char *, u_int);
+void gre_sre_asn_print(u_int8_t, u_int8_t, const u_char *, u_int);
 
-/* "Enhanced GRE" from RFC2637 - PPTP */
-#define GRE_AP		0x0080	/* Ack present */
+void
+gre_print(const u_char *bp, u_int length)
+{
+	u_int len = length, vers;
 
-#define GRE_MBZ_MASK	0x0078	/* not defined */
+	if (len < 2) {
+		printf("[|gre]");
+		return;
+	}
+	vers = EXTRACT_16BITS(bp) & 7;
+
+	if (vers == 0)
+		gre_print_0(bp, len);
+	else if (vers == 1)
+		gre_print_1(bp, len);
+	else
+		printf("gre-unknown-version=%u", vers);
+	return;
+
+}
 
-/*
- * Deencapsulate and print a GRE-tunneled IP datagram
- */
 void
-gre_print(const u_char *bp, u_int length)
+gre_print_0(const u_char *bp, u_int length)
 {
-	const u_char *cp = bp + 4;
-	const struct gre *gre;
-	u_int16_t flags, proto;
-	u_short ver=0;
-	u_short extracted_ethertype;
-
-	gre = (const struct gre *)bp;
-
-	TCHECK(gre->proto);
-	flags = EXTRACT_16BITS(&gre->flags);
-	proto = EXTRACT_16BITS(&gre->proto);
-	(void)printf("gre ");
-
-	if (flags) {
-		/* Decode the flags */
-		putchar('[');
-		if (flags & GRE_CP)
-			putchar('C');
-		if (flags & GRE_RP)
-			putchar('R');
-		if (flags & GRE_KP)
-			putchar('K');
-		if (flags & GRE_SP)
-			putchar('S');
-		if (flags & GRE_sP)
-			putchar('s');
-		if (flags & GRE_AP)
-			putchar('A');
-		if (flags & GRE_RECUR_MASK)
-			printf("R%x", (flags & GRE_RECUR_MASK) >> GRE_RECUR_SHIFT);
-		ver = flags & GRE_VER_MASK;
-		printf("v%u", ver);
-
-		if (flags & GRE_MBZ_MASK)
-			printf("!%x", flags & GRE_MBZ_MASK);
-		fputs("] ", stdout);
-	}
-
-	if (flags & GRE_COP) {
-		int checksum, offset;
-
-		TCHECK2(*cp, 4);
-		checksum = EXTRACT_16BITS(cp);
-		offset = EXTRACT_16BITS(cp + 2);
-
-		if (flags & GRE_CP) {
-			/* Checksum present */
-
-			/* todo: check checksum */
-			if (vflag > 1)
-				printf("C:%04x ", checksum);
-		}
-		if (flags & GRE_RP) {
-			/* Offset present */
+	u_int len = length;
+	u_int16_t flags, prot;
 
-			if (vflag > 1)
-				printf("O:%04x ", offset);
-		}
-		cp += 4;	/* skip checksum and offset */
+	flags = EXTRACT_16BITS(bp);
+	if (vflag) {
+		printf("[%s%s%s%s%s] ",
+		    (flags & GRE_CP) ? "C" : "",
+		    (flags & GRE_RP) ? "R" : "",
+		    (flags & GRE_KP) ? "K" : "",
+		    (flags & GRE_SP) ? "S" : "",
+		    (flags & GRE_sP) ? "s" : "");
 	}
+
+	len -= 2;
+	bp += 2;
+
+	if (len < 2)
+		goto trunc;
+	prot = EXTRACT_16BITS(bp);
+	len -= 2;
+	bp += 2;
+
+	if ((flags & GRE_CP) | (flags & GRE_RP)) {
+		if (len < 2)
+			goto trunc;
+		if (vflag)
+			printf("sum 0x%x ", EXTRACT_16BITS(bp));
+		bp += 2;
+		len -= 2;
+
+		if (len < 2)
+			goto trunc;
+		printf("off 0x%x ", EXTRACT_16BITS(bp));
+		bp += 2;
+		len -= 2;
+	}
+
 	if (flags & GRE_KP) {
-		TCHECK2(*cp, 4);
-		if (ver == 1) { 	/* PPTP */
-			if (vflag > 1)
-				printf("PL:%u ", EXTRACT_16BITS(cp));
-			printf("ID:%04x ", EXTRACT_16BITS(cp+2));
-		}
-		else
-			printf("K:%08x ", EXTRACT_32BITS(cp));
-		cp += 4;	/* skip key */
+		if (len < 4)
+			goto trunc;
+		printf("key=0x%x ", EXTRACT_32BITS(bp));
+		bp += 4;
+		len -= 4;
 	}
+
 	if (flags & GRE_SP) {
-		TCHECK2(*cp, 4);
-		printf("S:%u ", EXTRACT_32BITS(cp));
-		cp += 4;	/* skip seq */
+		if (len < 4)
+			goto trunc;
+		printf("seq=0x%x ", EXTRACT_32BITS(bp));
+		bp += 4;
+		len -= 4;
 	}
-	if (flags & GRE_AP && ver >= 1) {
-		TCHECK2(*cp, 4);
-		printf("A:%u ", EXTRACT_32BITS(cp));
-		cp += 4;	/* skip ack */
+
+	if (flags & GRE_RP) {
+		for (;;) {
+			u_int16_t af;
+			u_int8_t sreoff;
+			u_int8_t srelen;
+
+			if (len < 4)
+				goto trunc;
+			af = EXTRACT_16BITS(bp);
+			sreoff = *(bp + 2);
+			srelen = *(bp + 3);
+			bp += 4;
+			len -= 4;
+
+			if (af == 0 && srelen == 0)
+				break;
+
+			gre_sre_print(af, sreoff, srelen, bp, len);
+
+			if (len < srelen)
+				goto trunc;
+			bp += srelen;
+			len -= srelen;
+		}
+	}
+
+	switch (prot) {
+	case GREPROTO_IP:
+		ip_print(bp, len);
+		break;
+	default:
+		printf("gre-proto-0x%x", prot);
 	}
-	/* We don't support routing fields (variable length) now. Punt. */
-	if (flags & GRE_RP)
+	return;
+
+trunc:
+	printf("[|gre]");
+}
+
+void
+gre_print_1(const u_char *bp, u_int length)
+{
+	u_int len = length;
+	u_int16_t flags, prot;
+
+	flags = EXTRACT_16BITS(bp);
+	len -= 2;
+	bp += 2;
+
+	if (vflag) {
+		printf("[%s%s%s%s%s%s] ",
+		    (flags & GRE_CP) ? "C" : "",
+		    (flags & GRE_RP) ? "R" : "",
+		    (flags & GRE_KP) ? "K" : "",
+		    (flags & GRE_SP) ? "S" : "",
+		    (flags & GRE_sP) ? "s" : "",
+		    (flags & GRE_AP) ? "A" : "");
+	}
+
+	if (len < 2)
+		goto trunc;
+	prot = EXTRACT_16BITS(bp);
+	len -= 2;
+	bp += 2;
+
+	if (flags & GRE_CP) {
+		printf("cpset! ");
 		return;
+	}
+	if (flags & GRE_RP) {
+		printf("rpset! ");
+		return;
+	}
+	if ((flags & GRE_KP) != 0) {
+		printf("kpunset! ");
+		return;
+	}
+	if (flags & GRE_sP) {
+		printf("spset! ");
+		return;
+	}
 
-	TCHECK(cp[0]);
+	if (flags & GRE_KP) {
+		u_int32_t k;
+
+		if (len < 4)
+			goto trunc;
+		k = EXTRACT_32BITS(bp);
+		printf("key=0x%x call=0x%x ", (k >> 16) & 0xffff, k & 0xffff);
+		len -= 4;
+		bp += 4;
+	}
 
-	length -= cp - bp;
-	if (ether_encap_print(proto, cp, length, length,
-	    &extracted_ethertype) == 0)
-		printf("gre-proto-0x%04X", proto);
+	if (flags & GRE_SP) {
+		if (len < 4)
+			goto trunc;
+		printf("seq=0x%x ", EXTRACT_32BITS(bp));
+		bp += 4;
+		len -= 4;
+	}
+
+	if (flags & GRE_AP) {
+		if (len < 4)
+			goto trunc;
+		printf("ack=0x%x ", EXTRACT_32BITS(bp));
+		bp += 4;
+		len -= 4;
+	}
+
+	if ((flags & GRE_SP) == 0) {
+		printf("no-payload ");
+		return;
+	}
+
+	switch (prot) {
+	case GREPROTO_PPP:
+		printf("gre-ppp-payload ");
+		break;
+	default:
+		printf("gre-proto-0x%x ", prot);
+		break;
+	}
 	return;
 
 trunc:
-	fputs("[|gre]", stdout);
+	printf("[|gre]");
+}
+
+void
+gre_sre_print(u_int16_t af, u_int8_t sreoff, u_int8_t srelen,
+    const u_char *bp, u_int len)
+{
+	switch (af) {
+	case GRESRE_IP:
+		printf("(rtaf=ip");
+		gre_sre_ip_print(sreoff, srelen, bp, len);
+		printf(") ");
+		break;
+	case GRESRE_ASN:
+		printf("(rtaf=asn");
+		gre_sre_asn_print(sreoff, srelen, bp, len);
+		printf(") ");
+		break;
+	default:
+		printf("(rtaf=0x%x) ", af);
+	}
+}
+void
+gre_sre_ip_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len)
+{
+	struct in_addr a;
+	const u_char *up = bp;
 
+	if (sreoff & 3) {
+		printf(" badoffset=%u", sreoff);
+		return;
+	}
+	if (srelen & 3) {
+		printf(" badlength=%u", srelen);
+		return;
+	}
+	if (sreoff >= srelen) {
+		printf(" badoff/len=%u/%u", sreoff, srelen);
+		return;
+	}
+
+	for (;;) {
+		if (len < 4 || srelen == 0)
+			return;
+
+		memcpy(&a, bp, sizeof(a));
+		printf(" %s%s",
+		    ((bp - up) == sreoff) ? "*" : "",
+		    inet_ntoa(a));
+
+		bp += 4;
+		len -= 4;
+		srelen -= 4;
+	}
+}
+
+void
+gre_sre_asn_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len)
+{
+	const u_char *up = bp;
+
+	if (sreoff & 1) {
+		printf(" badoffset=%u", sreoff);
+		return;
+	}
+	if (srelen & 1) {
+		printf(" badlength=%u", srelen);
+		return;
+	}
+	if (sreoff >= srelen) {
+		printf(" badoff/len=%u/%u", sreoff, srelen);
+		return;
+	}
+
+	for (;;) {
+		if (len < 2 || srelen == 0)
+			return;
+
+		printf(" %s%x",
+		    ((bp - up) == sreoff) ? "*" : "",
+		    EXTRACT_16BITS(bp));
+
+		bp += 2;
+		len -= 2;
+		srelen -= 2;
+	}
 }