Netlink: Ignore dead routes (df83f626) · Commits · 戴 / Bird

With net.ipv4.conf.XXX.ignore_routes_with_linkdown sysctl, a user can ensure the kernel does not use a route whose target interface is down. Such route is marked with a 'dead' / RTNH_F_DEAD flag. Ignore these routes or multipath nexthops during scan. Thanks to Vincent Bernat for the original patch.

sysdep/linux/netlink.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -697,6 +697,9 @@ nl_parse_multipath(struct nl_parse_state s, struct krt_proto p, struct rtattr
		if ((len < sizeof(*nh)) \|\| (len < nh->rtnh_len))
		return NULL;

		if (nh->rtnh_flags & RTNH_F_DEAD)
		goto next;

		*last = rv = lp_allocz(s->pool, NEXTHOP_MAX_SIZE);
		last = &(rv->next);

		@@ -772,7 +775,7 @@ nl_parse_multipath(struct nl_parse_state s, struct krt_proto p, struct rtattr
		}
		#endif


		next:
		len -= NLMSG_ALIGN(nh->rtnh_len);
		nh = RTNH_NEXT(nh);
		}
		@@ -1683,6 +1686,9 @@ nl_parse_route(struct nl_parse_state s, struct nlmsghdr h)
		break;
		}

		if (i->rtm_flags & RTNH_F_DEAD)
		return;

		ra->nh.iface = if_find_by_index(oif);
		if (!ra->nh.iface)
		{

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