X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/881c14ce532b0fa569c8ab4908c6f8e9b66f34b9..c23f7b7dcf9c014cf531d75c22cc254c7ca35e55:/print-cdp.c

diff --git a/print-cdp.c b/print-cdp.c
index e0b86257..caa8f1ef 100644
--- a/print-cdp.c
+++ b/print-cdp.c
@@ -26,7 +26,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.8 2001-06-15 20:52:12 fenner Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.11 2001-09-17 21:57:56 fenner Exp $";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -54,7 +54,7 @@ void
 cdp_print(const u_char *p, u_int length, u_int caplen,
 	  const u_char *esrc, const u_char *edst)
 {
-	int i;
+	u_int i;
 	int type, len;
 
 	/* Cisco Discovery Protocol */
@@ -142,13 +142,29 @@ trunc:
 	printf("[|cdp]");
 }
 
+/*
+ * Protocol type values.
+ *
+ * PT_NLPID means that the protocol type field contains an OSI NLPID.
+ *
+ * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
+ * LLC header that specifies that the payload is for that protocol.
+ */
+#define PT_NLPID		1	/* OSI NLPID */
+#define PT_IEEE_802_2		2	/* IEEE 802.2 LLC header */
+
 static int
 cdp_print_addr(const u_char * p, int l)
 {
-	int pl, al, num;
+	int pt, pl, al, num;
 	const u_char *endp = p + l;
+#ifdef INET6
+	static u_char prot_ipv6[] = {
+		0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
+	};
+#endif
 
-	num = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3];
+	num = EXTRACT_32BITS(p);
 	p += 4;
 
 	printf(" (%d): ", num);
@@ -156,35 +172,66 @@ cdp_print_addr(const u_char * p, int l)
 	while (p < endp && num >= 0) {
 		if (p + 2 > endp)
 			goto trunc;
-		pl = p[1];
+		pt = p[0];		/* type of "protocol" field */
+		pl = p[1];		/* length of "protocol" field */
 		p += 2;
 
-		/* special case: IPv4, protocol type=0xcc, addr. length=4 */
-		if (p + 3 > endp)
+		if (p + pl + 2 > endp)
 			goto trunc;
-		if (pl == 1 && *p == 0xcc && p[1] == 0 && p[2] == 4) {
+		al = EXTRACT_16BITS(&p[pl]);	/* address length */
+
+		if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) {
+			/*
+			 * IPv4: protocol type = NLPID, protocol length = 1
+			 * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
+			 * address length = 4
+			 */
 			p += 3;
 
 			if (p + 4 > endp)
 				goto trunc;
-			printf("IPv4 %u.%u.%u.%u ", p[0], p[1], p[2], p[3]);
+			printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]);
 			p += 4;
-		} else {	/* generic case: just print raw data */
+		}
+#ifdef INET6
+		else if (pt == PT_IEEE_802_2 && pl == 8 &&
+		    memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
+			/*
+			 * IPv6: protocol type = IEEE 802.2 header,
+			 * protocol length = 8 (size of LLC+SNAP header),
+			 * protocol = LLC+SNAP header with the IPv6
+			 * Ethertype, address length = 16
+			 */
+			p += 10; 
+			if (p + al > endp)
+				goto trunc;
+
+			printf("IPv6 %s", ip6addr_string(p));
+			p += al;
+		}
+#endif
+		else {
+			/*
+			 * Generic case: just print raw data
+			 */
 			if (p + pl > endp)
 				goto trunc;
 			printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
 			while (pl-- > 0)
 				printf(" %02x", *p++);
-			al = (*p << 8) + *(p + 1);
-			if (p + 2 + al > endp)
+			if (p + 2 > endp)
 				goto trunc;
+			al = (*p << 8) + *(p + 1);
 			printf(", al=%d, a=", al);
 			p += 2;
+			if (p + al > endp)
+				goto trunc;
 			while (al-- > 0)
 				printf(" %02x", *p++);
 		}
-		printf("  ");
 		num--;
+		if (num)
+			printf(" ");
 	}
 
 	return 0;