X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/728fd81dac6cc1f1420c7836defc6b01e98c9f61..4c2790a43252b9cac1fe7f6b50b51c3c55d2370a:/print-pppoe.c

diff --git a/print-pppoe.c b/print-pppoe.c
index d7baa20d..bcc976c4 100644
--- a/print-pppoe.c
+++ b/print-pppoe.c
@@ -23,7 +23,7 @@
 
 #ifndef lint
 static const char rcsid[] _U_ =
-"@(#) $Header: /tcpdump/master/tcpdump/print-pppoe.c,v 1.29 2004-08-27 03:28:58 guy Exp $ (LBL)";
+"@(#) $Header: /tcpdump/master/tcpdump/print-pppoe.c,v 1.31 2005-04-26 19:48:38 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -70,6 +70,7 @@ enum {
 	PPPOE_AC_COOKIE = 0x0104,
 	PPPOE_VENDOR = 0x0105,
 	PPPOE_RELAY_SID = 0x0110,
+	PPPOE_MAX_PAYLOAD = 0x0120,
 	PPPOE_SERVICE_NAME_ERROR = 0x0201,
 	PPPOE_AC_SYSTEM_ERROR = 0x0202,
 	PPPOE_GENERIC_ERROR = 0x0203
@@ -83,6 +84,7 @@ static struct tok pppoetag2str[] = {
 	{ PPPOE_AC_COOKIE, "AC-Cookie" },
 	{ PPPOE_VENDOR, "Vendor-Specific" },
 	{ PPPOE_RELAY_SID, "Relay-Session-ID" },
+	{ PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
 	{ PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
 	{ PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
 	{ PPPOE_GENERIC_ERROR, "Generic-Error" },
@@ -101,9 +103,15 @@ pppoe_if_print(const struct pcap_pkthdr *h, register const u_char *p)
 u_int
 pppoe_print(register const u_char *bp, u_int length)
 {
-	u_short pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid, pppoe_length;
+	u_int16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
+	u_int pppoe_length;
 	const u_char *pppoe_packet, *pppoe_payload;
 
+	if (length < PPPOE_HDRLEN) {
+		(void)printf("truncated-pppoe %u", length);
+		return (length);
+	}
+	length -= PPPOE_HDRLEN;
 	pppoe_packet = bp;
 	TCHECK2(*pppoe_packet, PPPOE_HDRLEN);
 	pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
@@ -113,11 +121,6 @@ pppoe_print(register const u_char *bp, u_int length)
 	pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
 	pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
 
-	if (snapend < pppoe_payload) {
-		printf(" truncated PPPoE");
-		return (PPPOE_HDRLEN);
-	}
-
 	if (pppoe_ver != 1) {
 		printf(" [ver %d]",pppoe_ver);
 	}
@@ -127,27 +130,16 @@ pppoe_print(register const u_char *bp, u_int length)
 
 	printf("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
 	if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
-		printf(" [len %d!]",pppoe_length);
+		printf(" [len %u!]",pppoe_length);
+	}
+	if (pppoe_length > length) {
+		printf(" [len %u > %u!]", pppoe_length, length);
+		pppoe_length = length;
 	}
 	if (pppoe_sessionid) {
 		printf(" [ses 0x%x]", pppoe_sessionid);
 	}
 
-	if (pppoe_payload + pppoe_length < snapend && snapend-pppoe_payload+14 > 64) {
-		/* (small packets are probably just padded up to the ethernet
-		   minimum of 64 bytes) */
-		printf(" [length %d (%d extra bytes)]",
-		    pppoe_length, snapend - pppoe_payload - pppoe_length);
-#if RESPECT_PAYLOAD_LENGTH
-		snapend = pppoe_payload+pppoe_length;
-#else
-		/* Actual PPPoE implementations appear to ignore the payload
-		   length and use the full ethernet frame anyways */
-		pppoe_length = snapend-pppoe_payload;
-#endif
-		
-	}
-
 	if (pppoe_code) {
 		/* PPP session packets don't contain tags */
 		u_short tag_type = 0xffff, tag_len;
@@ -155,11 +147,10 @@ pppoe_print(register const u_char *bp, u_int length)
 
 		/*
 		 * loop invariant:
-		 * p points to next tag,
+		 * p points to current tag,
 		 * tag_type is previous tag or 0xffff for first iteration
 		 */
-		while (tag_type && p + 4 < pppoe_payload + length &&
-		    p + 4 < snapend) {
+		while (tag_type && p < pppoe_payload + pppoe_length) {
 			TCHECK2(*p, 4);
 			tag_type = EXTRACT_16BITS(p);
 			tag_len = EXTRACT_16BITS(p + 2);