Restore packetp and snapend pointers once we're done with an incorrectly

aligned IP/IPv6 packet so that tcpdump can print hexdump of the whole
packet including the Ethernet header (if requested) and not only the
IP/IPv6 part of it.

ok jsg

2 files changed, 22 insertions, 11 deletions

diff --git a/usr.sbin/tcpdump/print-ip.c b/usr.sbin/tcpdump/print-ip.c
index c13550f7ae9..11c183ace1e 100644
--- a/usr.sbin/tcpdump/print-ip.c
+++ b/usr.sbin/tcpdump/print-ip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-ip.c,v 1.40 2014/12/03 13:19:03 mikeb Exp $	*/
+/*	$OpenBSD: print-ip.c,v 1.41 2014/12/03 13:22:18 mikeb Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -356,6 +356,8 @@ ip_print(register const u_char *bp, register u_int length)
 	register const struct ip *ip;
 	register u_int hlen, len, off;
 	register const u_char *cp;
+	const u_char *pktp = packetp;
+	const u_char *send = snapend;
 
 	ip = (const struct ip *)bp;
 	if ((u_char *)(ip + 1) > snapend) {
@@ -394,7 +396,7 @@ ip_print(register const u_char *bp, register u_int length)
 	TCHECK(*ip);
 	if (ip->ip_v != IPVERSION) {
 		(void)printf("bad-ip-version %u", ip->ip_v);
-		return;
+		goto out;
 	}
 
 	len = ntohs(ip->ip_len);
@@ -407,7 +409,7 @@ ip_print(register const u_char *bp, register u_int length)
 	hlen = ip->ip_hl * 4;
 	if (hlen < sizeof(struct ip) || hlen > len) {
 		(void)printf("bad-hlen %d", hlen);
-		return;
+		goto out;
 	}
 
 	len -= hlen;
@@ -472,7 +474,7 @@ ip_print(register const u_char *bp, register u_int length)
 			ip_print(cp, len);
 			if (! vflag) {
 				printf(" (encap)");
-				return;
+				goto out;
 			}
 			break;
 
@@ -489,7 +491,7 @@ ip_print(register const u_char *bp, register u_int length)
 			ip6_print(cp, len);
 			if (! vflag) {
  				printf(" (encap)");
- 				return;
+				goto out;
  			}
  			break;
 #endif /*INET6*/
@@ -506,7 +508,7 @@ ip_print(register const u_char *bp, register u_int length)
 			gre_print(cp, len);
 			if (! vflag) {
 				printf(" (gre encap)");
-				return;
+				goto out;
   			}
   			break;
 
@@ -535,7 +537,7 @@ ip_print(register const u_char *bp, register u_int length)
 			mobile_print(cp, len);
 			if (! vflag) {
 				printf(" (mobile encap)");
-				return;
+				goto out;
 			}
 			break;
 
@@ -660,6 +662,9 @@ ip_print(register const u_char *bp, register u_int length)
 		}
 		printf(")");
 	}
+out:
+	packetp = pktp;
+	snapend = send;
 	return;
 
 trunc:
diff --git a/usr.sbin/tcpdump/print-ip6.c b/usr.sbin/tcpdump/print-ip6.c
index 1df561fa839..c41973d768e 100644
--- a/usr.sbin/tcpdump/print-ip6.c
+++ b/usr.sbin/tcpdump/print-ip6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-ip6.c,v 1.18 2014/12/03 13:19:03 mikeb Exp $	*/
+/*	$OpenBSD: print-ip6.c,v 1.19 2014/12/03 13:22:18 mikeb Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
@@ -56,6 +56,8 @@ ip6_print(register const u_char *bp, register u_int length)
 	register int hlen;
 	register int len;
 	register const u_char *cp;
+	const u_char *pktp = packetp;
+	const u_char *send = snapend;
 	int nh;
 	u_int flow;
 
@@ -95,11 +97,11 @@ ip6_print(register const u_char *bp, register u_int length)
 
 	if (length < sizeof (struct ip6_hdr)) {
 		(void)printf("truncated-ip6 %d", length);
-		return;
+		goto out;
 	}
 	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 		(void)printf("bad-ip6-version %u", ip6->ip6_vfc >> 4);
-		return;
+		goto out;
 	}
 	hlen = sizeof(struct ip6_hdr);
 
@@ -206,7 +208,7 @@ ip6_print(register const u_char *bp, register u_int length)
 	}
 
  end:
-	
+
 	flow = ntohl(ip6->ip6_flow);
 #if 0
 	/* rfc1883 */
@@ -232,6 +234,10 @@ ip6_print(register const u_char *bp, register u_int length)
 			(void)printf(", hlim %d", (int)ip6->ip6_hlim);
 		printf(")");
 	}
+
+ out:
+	packetp = pktp;
+	snapend = send;
 }
 
 #endif /* INET6 */