Use "len", not "payload_len", as we step through the packet; use

[tcpdump] / print-ip.c

diff --git a/print-ip.c b/print-ip.c
index 45e84f0cb03c9a686eaa4889becb26b0e89dae15..f426722296629fe1d64ab1c5422571358a93624e 100644 (file)
--- a/print-ip.c
+++ b/print-ip.c
@@ -19,6 +19,10 @@
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
+#ifndef lint
+static const char rcsid[] _U_ =
+    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.132 2003-11-19 00:36:07 guy Exp $ (LBL)";
+#endif
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
@@ -34,10 +38,6 @@
 #include "interface.h"
 #include "extract.h"                   /* must come after interface.h */
 
-#ifndef lint
-static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.129 2003-11-15 00:39:27 guy Exp $ (LBL)";
-#endif
 #include "ip.h"
 #include "ipproto.h"
 
@@ -358,6 +358,7 @@ ip_print(register const u_char *bp, register u_int length)
 {
        register const struct ip *ip;
        register u_int hlen, len, len0, off;
+       const u_char *ipend;
        register const u_char *cp;
        u_char nh;
        int advance;
@@ -383,14 +384,26 @@ ip_print(register const u_char *bp, register u_int length)
        }
        hlen = IP_HL(ip) * 4;
        if (hlen < sizeof (struct ip)) {
-               (void)printf("bad-hlen %d", hlen);
+               (void)printf("bad-hlen %u", hlen);
                return;
        }
 
        len = EXTRACT_16BITS(&ip->ip_len);
        if (length < len)
-               (void)printf("truncated-ip - %d bytes missing! ",
+               (void)printf("truncated-ip - %u bytes missing! ",
                        len - length);
+       if (len < hlen) {
+               (void)printf("bad-len %u", len);
+               return;
+       }
+
+       /*
+        * Cut off the snapshot length to the end of the IP payload.
+        */
+       ipend = bp + len;
+       if (ipend < snapend)
+               snapend = ipend;
+
        len -= hlen;
        len0 = len;
 
@@ -465,6 +478,8 @@ again:
                case IPPROTO_AH:
                        nh = *cp;
                        advance = ah_print(cp);
+                       if (advance <= 0)
+                               break;
                        cp += advance;
                        len -= advance;
                        goto again;
@@ -473,10 +488,10 @@ again:
                    {
                        int enh, padlen;
                        advance = esp_print(cp, (const u_char *)ip, &enh, &padlen);
+                       if (advance <= 0)
+                               break;
                        cp += advance;
                        len -= advance + padlen;
-                       if (enh < 0)
-                               break;
                        nh = enh & 0xff;
                        goto again;
                    }
@@ -485,10 +500,10 @@ again:
                    {
                        int enh;
                        advance = ipcomp_print(cp, &enh);
+                       if (advance <= 0)
+                               break;
                        cp += advance;
                        len -= advance;
-                       if (enh < 0)
-                               break;
                        nh = enh & 0xff;
                        goto again;
                    }