Date: Mon, 3 May 2010 09:31:51 +0000 (UTC) From: Bruce M Simpson <bms@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r207558 - stable/8/sys/netinet Message-ID: <201005030931.o439Vpic037309@svn.freebsd.org>
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Author: bms Date: Mon May 3 09:31:51 2010 New Revision: 207558 URL: http://svn.freebsd.org/changeset/base/207558 Log: MFC r207275: 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 Modified: stable/8/sys/netinet/igmp.c Directory Properties: stable/8/sys/ (props changed) stable/8/sys/amd64/include/xen/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) stable/8/sys/contrib/dev/acpica/ (props changed) stable/8/sys/contrib/pf/ (props changed) stable/8/sys/dev/xen/xenpci/ (props changed) stable/8/sys/geom/sched/ (props changed) Modified: stable/8/sys/netinet/igmp.c ============================================================================== --- stable/8/sys/netinet/igmp.c Mon May 3 09:28:10 2010 (r207557) +++ stable/8/sys/netinet/igmp.c Mon May 3 09:31:51 2010 (r207558) @@ -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) {
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