X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/27da447b2af03eb9ebe4c41b09be335dec89a103..296d466cd6bbf2f7e75e15bb6a01268e88c76ed0:/print-ip.c

diff --git a/print-ip.c b/print-ip.c
index fab8e0b7..a332bd78 100644
--- a/print-ip.c
+++ b/print-ip.c
@@ -21,9 +21,7 @@
 
 /* \summary: IP printer */
 
-#ifdef HAVE_CONFIG_H
 #include <config.h>
-#endif
 
 #include "netdissect-stdinc.h"
 
@@ -318,7 +316,7 @@ static const struct tok ip_frag_values[] = {
 void
 ip_print(netdissect_options *ndo,
 	 const u_char *bp,
-	 u_int length)
+	 const u_int length)
 {
 	const struct ip *ip;
 	u_int off;
@@ -329,6 +327,7 @@ ip_print(netdissect_options *ndo,
 	uint16_t sum, ip_sum;
 	const char *p_name;
 	int truncated = 0;
+	int presumed_tso = 0;
 
 	ndo->ndo_protocol = "ip";
 	ip = (const struct ip *)bp;
@@ -341,36 +340,29 @@ ip_print(netdissect_options *ndo,
 	ND_ICHECK_ZU(length, <, sizeof (struct ip));
 	ND_ICHECKMSG_U("version", IP_V(ip), !=, 4);
 
-	ND_TCHECK_SIZE(ip);
 	hlen = IP_HL(ip) * 4;
-	if (hlen < sizeof (struct ip)) {
-		ND_PRINT("bad-hlen %u", hlen);
-		return;
-	}
+	ND_ICHECKMSG_ZU("header length", hlen, <, sizeof (struct ip));
 
 	len = GET_BE_U_2(ip->ip_len);
-	if (length < len)
-		ND_PRINT("truncated-ip - %u bytes missing! ",
-			len - length);
-	if (len < hlen) {
-#ifdef GUESS_TSO
-            if (len) {
-                ND_PRINT("bad-len %u", len);
-                return;
-            } else {
-                /* we guess that it is a TSO send */
-                len = length;
-            }
-#else
-            ND_PRINT("bad-len %u", len);
-            return;
-#endif /* GUESS_TSO */
+	if (len > length) {
+		ND_PRINT("[total length %u > length %u]", len, length);
+		nd_print_invalid(ndo);
+		ND_PRINT(" ");
 	}
+	if (len == 0) {
+		/* we guess that it is a TSO send */
+		len = length;
+		presumed_tso = 1;
+	} else
+		ND_ICHECKMSG_U("total length", len, <, hlen);
 
+	ND_TCHECK_SIZE(ip);
 	/*
-	 * Cut off the snapshot length to the end of the IP payload.
+	 * Cut off the snapshot length to the end of the IP payload
+	 * or the end of the data in which it's contained, whichever
+	 * comes first.
 	 */
-	if (!nd_push_snaplen(ndo, bp, len)) {
+	if (!nd_push_snaplen(ndo, bp, ND_MIN(length, len))) {
 		(*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
 			"%s: can't push snaplen on buffer stack", __func__);
 	}
@@ -419,9 +411,12 @@ ip_print(netdissect_options *ndo,
                          tok2str(ipproto_values, "unknown", ip_proto),
                          ip_proto);
 
-            ND_PRINT(", length %u", GET_BE_U_2(ip->ip_len));
+	    if (presumed_tso)
+                ND_PRINT(", length %u [was 0, presumed TSO]", length);
+	    else
+                ND_PRINT(", length %u", GET_BE_U_2(ip->ip_len));
 
-            if ((hlen - sizeof(struct ip)) > 0) {
+            if ((hlen > sizeof(struct ip))) {
                 ND_PRINT(", options (");
                 if (ip_optprint(ndo, (const u_char *)(ip + 1),
                     hlen - sizeof(struct ip)) == -1) {