From bed50e27dd14aa98a89a2c9e0e7a63a87bcaa830 Mon Sep 17 00:00:00 2001 From: Shaun Crampton Date: Wed, 17 Jun 2015 16:14:41 -0700 Subject: [PATCH 3/3] Disable recursive route check for GCE compatibility. GCE uses a /32 for VM IPs with a default gateway that is, thus, off-subnet. This patch removes a check in BIRD that prevents BIRD from accepting such a route as a valid next hop. The following trail asserts that the check is not really needed but that it is normally a useful sanity check: https://www.mail-archive.com/bird-users@atrey.karlin.mff.cuni.cz/msg02600.html Ideally GCE would set the online flag on the route or use a link-local IP instead but that is unlikely to change. --- sysdep/linux/netlink.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c index d754df7..3ac5b27 100644 --- a/sysdep/linux/netlink.c +++ b/sysdep/linux/netlink.c @@ -521,8 +521,7 @@ nl_parse_multipath(struct krt_proto *p, struct rtattr *ra) memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr)); ipa_ntoh(rv->gw); - neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface, - (nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); + neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface, NEF_ONLINK); if (!ng || (ng->scope == SCOPE_HOST)) return NULL; } @@ -1290,8 +1289,7 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h) return; #endif - ng = neigh_find2(&p->p, &ra->gw, ra->iface, - (i->rtm_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); + ng = neigh_find2(&p->p, &ra->gw, ra->iface, NEF_ONLINK); if (!ng || (ng->scope == SCOPE_HOST)) { log(L_ERR "KRT: Received route %I/%d with strange next-hop %I", -- 2.7.4