From owner-svn-src-all@FreeBSD.ORG  Tue Apr 27 14:14:21 2010
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id A8A7F1065673;
	Tue, 27 Apr 2010 14:14:21 +0000 (UTC) (envelope-from bms@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id 963148FC0C;
	Tue, 27 Apr 2010 14:14:21 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o3REELYr031094;
	Tue, 27 Apr 2010 14:14:21 GMT (envelope-from bms@svn.freebsd.org)
Received: (from bms@localhost)
	by svn.freebsd.org (8.14.3/8.14.3/Submit) id o3REELE9031092;
	Tue, 27 Apr 2010 14:14:21 GMT (envelope-from bms@svn.freebsd.org)
Message-Id: <201004271414.o3REELE9031092@svn.freebsd.org>
From: Bruce M Simpson <bms@FreeBSD.org>
Date: Tue, 27 Apr 2010 14:14:21 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-head@freebsd.org
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r207275 - head/sys/netinet
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
	user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 27 Apr 2010 14:14:21 -0000

Author: bms
Date: Tue Apr 27 14:14:21 2010
New Revision: 207275
URL: http://svn.freebsd.org/changeset/base/207275

Log:
  Fix a regression where DVMRP diagnostic traffic, such as that used
  by mrinfo and mtrace, was dropped by the IGMP TTL check. IGMP control
  traffic must always have a TTL of 1.
  
  Submitted by:	Matthew Luckie
  MFC after:	3 days

Modified:
  head/sys/netinet/igmp.c

Modified: head/sys/netinet/igmp.c
==============================================================================
--- head/sys/netinet/igmp.c	Tue Apr 27 13:50:15 2010	(r207274)
+++ head/sys/netinet/igmp.c	Tue Apr 27 14:14:21 2010	(r207275)
@@ -1468,12 +1468,6 @@ igmp_input(struct mbuf *m, int off)
 	}
 	ip = mtod(m, struct ip *);
 
-	if (ip->ip_ttl != 1) {
-		IGMPSTAT_INC(igps_rcv_badttl);
-		m_freem(m);
-		return;
-	}
-
 	/*
 	 * Validate checksum.
 	 */
@@ -1488,6 +1482,17 @@ igmp_input(struct mbuf *m, int off)
 	m->m_data -= iphlen;
 	m->m_len += iphlen;
 
+	/*
+	 * IGMP control traffic is link-scope, and must have a TTL of 1.
+	 * DVMRP traffic (e.g. mrinfo, mtrace) is an exception;
+	 * probe packets may come from beyond the LAN.
+	 */
+	if (igmp->igmp_type != IGMP_DVMRP && ip->ip_ttl != 1) {
+		IGMPSTAT_INC(igps_rcv_badttl);
+		m_freem(m);
+		return;
+	}
+
 	switch (igmp->igmp_type) {
 	case IGMP_HOST_MEMBERSHIP_QUERY:
 		if (igmplen == IGMP_MINLEN) {