diff options
| -rw-r--r-- | sys/netinet/igmp.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/sys/netinet/igmp.c b/sys/netinet/igmp.c index f9f6381..d4c8e99 100644 --- a/sys/netinet/igmp.c +++ b/sys/netinet/igmp.c @@ -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) { |
