From 3eca6f099d5a3aac0b66dfbf98fd8be84ea426b7 Mon Sep 17 00:00:00 2001 From: Denis Ovsienko Date: Thu, 22 Sep 2011 12:48:14 +0400 Subject: bgpd: improve NEXT_HOP attribute checks (BZ#680) * lib/prefix.h * IPV4_CLASS_DE(): new helper macro * bgp_attr.c * bgp_attr_nexthop(): add check for "partial" bit, refresh flag error reporting, explain meaning of RFC4271 section 6.3 and implement it --- bgpd/bgp_attr.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 47 insertions(+), 8 deletions(-) (limited to 'bgpd') diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 989c22b1..1300ab84 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -898,17 +898,37 @@ bgp_attr_nexthop (struct peer *peer, bgp_size_t length, struct attr *attr, u_char flag, u_char *startp) { bgp_size_t total; + in_addr_t nexthop_h, nexthop_n; total = length + (CHECK_FLAG (flag, BGP_ATTR_FLAG_EXTLEN) ? 4 : 3); - /* Flag check. */ - if (CHECK_FLAG (flag, BGP_ATTR_FLAG_OPTIONAL) - || ! CHECK_FLAG (flag, BGP_ATTR_FLAG_TRANS)) + /* Flags check. */ + if (CHECK_FLAG (flag, BGP_ATTR_FLAG_OPTIONAL)) { - zlog (peer->log, LOG_ERR, - "Origin attribute flag isn't transitive %d", flag); - bgp_notify_send_with_data (peer, - BGP_NOTIFY_UPDATE_ERR, + zlog (peer->log, LOG_ERR, + "NEXT_HOP attribute must not be flagged as \"optional\" (%u)", flag); + bgp_notify_send_with_data (peer, + BGP_NOTIFY_UPDATE_ERR, + BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR, + startp, total); + return -1; + } + if (! CHECK_FLAG (flag, BGP_ATTR_FLAG_TRANS)) + { + zlog (peer->log, LOG_ERR, + "NEXT_HOP attribute must be flagged as \"transitive\" (%u)", flag); + bgp_notify_send_with_data (peer, + BGP_NOTIFY_UPDATE_ERR, + BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR, + startp, total); + return -1; + } + if (CHECK_FLAG (flag, BGP_ATTR_FLAG_PARTIAL)) + { + zlog (peer->log, LOG_ERR, + "NEXT_HOP attribute must not be flagged as \"partial\" (%u)", flag); + bgp_notify_send_with_data (peer, + BGP_NOTIFY_UPDATE_ERR, BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR, startp, total); return -1; @@ -927,7 +947,26 @@ bgp_attr_nexthop (struct peer *peer, bgp_size_t length, return -1; } - attr->nexthop.s_addr = stream_get_ipv4 (peer->ibuf); + /* According to section 6.3 of RFC4271, syntactically incorrect NEXT_HOP + attribute must result in a NOTIFICATION message (this is implemented below). + At the same time, semantically incorrect NEXT_HOP is more likely to be just + logged locally (this is implemented somewhere else). The UPDATE message + gets ignored in any of these cases. */ + nexthop_n = stream_get_ipv4 (peer->ibuf); + nexthop_h = ntohl (nexthop_n); + if (IPV4_NET0 (nexthop_h) || IPV4_NET127 (nexthop_h) || IPV4_CLASS_DE (nexthop_h)) + { + char buf[INET_ADDRSTRLEN]; + inet_ntop (AF_INET, &nexthop_h, buf, INET_ADDRSTRLEN); + zlog (peer->log, LOG_ERR, "Martian nexthop %s", buf); + bgp_notify_send_with_data (peer, + BGP_NOTIFY_UPDATE_ERR, + BGP_NOTIFY_UPDATE_INVAL_NEXT_HOP, + startp, total); + return -1; + } + + attr->nexthop.s_addr = nexthop_n; attr->flag |= ATTR_FLAG_BIT (BGP_ATTR_NEXT_HOP); return 0; -- cgit v1.2.1