From: Guy Harris <guy@alum.mit.edu>
Date: Sun, 5 Jul 2015 01:45:11 +0000 (-0700)
Subject: Stop processing IPPROTO_ values once we hit IPPROTO_IPCOMP.
X-Git-Tag: tcpdump-4.9.0-bp~82
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/406b0e3e9293a545c831ee9ed1558c3a5f5bd60d

Stop processing IPPROTO_ values once we hit IPPROTO_IPCOMP.

It's not like, for example, AH or ESP, where, following the header for
that protocol, there's another protocol with its own payload.
---

diff --git a/configure b/configure
index 0a0dfdc1..03c69c58 100755
--- a/configure
+++ b/configure
@@ -5451,7 +5451,6 @@ fi
 
 
 
-
                 LBL_LIBS="$LIBS"
     pfopen=/usr/examples/packetfilter/pfopen.c
     if test -f $pfopen ; then
diff --git a/configure.in b/configure.in
index d7484ede..a78a1266 100644
--- a/configure.in
+++ b/configure.in
@@ -418,9 +418,6 @@ dnl Some platforms may need -lnsl for getrpcbynumber.
 AC_SEARCH_LIBS(getrpcbynumber, nsl,
     AC_DEFINE(HAVE_GETRPCBYNUMBER, 1, [define if you have getrpcbynumber()]))
 
-dnl AC_CHECK_LIB(z, uncompress)
-dnl AC_CHECK_HEADERS(zlib.h)
-
 AC_LBL_LIBPCAP(V_PCAPDEP, V_INCLS)
 
 #
diff --git a/netdissect.h b/netdissect.h
index 3bba2cb1..ea77e74d 100644
--- a/netdissect.h
+++ b/netdissect.h
@@ -524,7 +524,7 @@ extern void ip6_print(netdissect_options *, const u_char *, u_int);
 extern void ipN_print(netdissect_options *, const u_char *, u_int);
 extern void ip_print(netdissect_options *, const u_char *, u_int);
 extern void ip_print_inner(netdissect_options *, const u_char *, u_int, u_int nh, const u_char *);
-extern int ipcomp_print(netdissect_options *, register const u_char *, int *);
+extern void ipcomp_print(netdissect_options *, register const u_char *);
 extern void ipx_netbios_print(netdissect_options *, const u_char *, u_int);
 extern void ipx_print(netdissect_options *, const u_char *, u_int);
 extern void isakmp_print(netdissect_options *, const u_char *, u_int, const u_char *);
diff --git a/print-ip.c b/print-ip.c
index 38cc2315..bb1554f9 100644
--- a/print-ip.c
+++ b/print-ip.c
@@ -358,14 +358,14 @@ again:
 
 	case IPPROTO_IPCOMP:
 	{
-		int enh;
-		ipds->advance = ipcomp_print(ndo, ipds->cp, &enh);
-		if (ipds->advance <= 0)
-			break;
-		ipds->cp += ipds->advance;
-		ipds->len -= ipds->advance;
-		ipds->nh = enh & 0xff;
-		goto again;
+		ipcomp_print(ndo, ipds->cp);
+		/*
+		 * Either this has decompressed the payload and
+		 * printed it, in which case there's nothing more
+		 * to do, or it hasn't, in which case there's
+		 * nothing more to do.
+		 */
+		break;
 	}
 
 	case IPPROTO_SCTP:
diff --git a/print-ip6.c b/print-ip6.c
index c5811300..2e1803f0 100644
--- a/print-ip6.c
+++ b/print-ip6.c
@@ -353,9 +353,14 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length)
 		    }
 		case IPPROTO_IPCOMP:
 		    {
-			int enh;
-			advance = ipcomp_print(ndo, cp, &enh);
-			nh = enh & 0xff;
+			ipcomp_print(ndo, cp);
+			/*
+			 * Either this has decompressed the payload and
+			 * printed it, in which case there's nothing more
+			 * to do, or it hasn't, in which case there's
+			 * nothing more to do.
+			 */
+			advance = -1;
 			break;
 		    }
 
diff --git a/print-ipcomp.c b/print-ipcomp.c
index 354eef35..291caa97 100644
--- a/print-ipcomp.c
+++ b/print-ipcomp.c
@@ -33,49 +33,37 @@ struct ipcomp {
 	uint16_t comp_cpi;	/* Compression parameter index */
 };
 
-#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
-#include <zlib.h>
-#endif
-
 #include "netdissect.h"
 #include "extract.h"
 
-int
-ipcomp_print(netdissect_options *ndo, register const u_char *bp, int *nhdr _U_)
+void
+ipcomp_print(netdissect_options *ndo, register const u_char *bp)
 {
 	register const struct ipcomp *ipcomp;
 	uint16_t cpi;
-#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
-	int advance;
-#endif
 
 	ipcomp = (const struct ipcomp *)bp;
-	ND_TCHECK(ipcomp->comp_cpi);
+	ND_TCHECK(*ipcomp);
 	cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
 
 	ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
 
-#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
-	if (1)
-		goto fail;
-
 	/*
-	 * We may want to decompress the packet here.  Packet buffer
-	 * management is a headache (if we decompress, packet will become
-	 * larger).
+	 * XXX - based on the CPI, we could decompress the packet here.
+	 * Packet buffer management is a headache (if we decompress,
+	 * packet will become larger).
+	 *
+	 * We would decompress the packet and then call a routine that,
+	 * based on ipcomp->comp_nxt, dissects the decompressed data.
+	 *
+	 * Until we do that, however, we just return -1, so that
+	 * the loop that processes "protocol"/"next header" types
+	 * stops - there's nothing more it can do with a compressed
+	 * payload.
 	 */
-	if (nhdr)
-		*nhdr = ipcomp->comp_nxt;
-	advance = sizeof(struct ipcomp);
+	return;
 
-	ND_PRINT((ndo, ": "));
-	return advance;
-
-#endif
 trunc:
 	ND_PRINT((ndo, "[|IPCOMP]"));
-#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
-fail:
-#endif
-	return -1;
+	return;
 }