X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/0f9428904ade10d6cf116e00b4bcc63e233b0a79..c5a34f01b4d03a0c24f9abb57f0db45c502aceb5:/print-udp.c

diff --git a/print-udp.c b/print-udp.c
index 231d8b4f..77bf330e 100644
--- a/print-udp.c
+++ b/print-udp.c
@@ -389,7 +389,8 @@ udp_print(netdissect_options *ndo, const u_char *bp, u_int length,
 	const struct ip *ip;
 	const u_char *cp;
 	const u_char *ep = ndo->ndo_snapend;
-	uint16_t sport, dport, ulen;
+	uint16_t sport, dport;
+	u_int ulen;
 	const struct ip6_hdr *ip6;
 
 	ndo->ndo_protocol = "udp";
@@ -417,6 +418,13 @@ udp_print(netdissect_options *ndo, const u_char *bp, u_int length,
 		goto trunc;
 	}
 	ulen = GET_BE_U_2(up->uh_ulen);
+	/*
+	 * IPv6 Jumbo Datagrams; see RFC 2675.
+	 * If the length is zero, and the length provided to us is
+	 * > 65535, use the provided length as the length.
+	 */
+	if (ulen == 0 && length > 65535)
+		ulen = length;
 	if (ulen < sizeof(struct udphdr)) {
 		udpipaddr_print(ndo, ip, sport, dport);
 		ND_PRINT("truncated-udplength %u", ulen);
@@ -571,7 +579,7 @@ udp_print(netdissect_options *ndo, const u_char *bp, u_int length,
 					ND_PRINT("[udp sum ok] ");
 			}
 		}
-		else if (IP_V(ip) == 6 && ip6->ip6_plen) {
+		else if (IP_V(ip) == 6) {
 			/* for IPv6, UDP checksum is mandatory */
 			if (ND_TTEST_LEN(cp, length)) {
 				sum = udp6_cksum(ndo, ip6, up, length + sizeof(struct udphdr));