Commit 1f56a01f authored Apr 28, 2015 by Martin KaFai Lau Committed by David S. Miller May 01, 2015

ipv6: Consider RTF_CACHE when searching the fib6 tree



It is a prep work for the later bug-fix patch which will stop /128 route
from disappearing after pmtu update.

The later bug-fix patch will allow a /128 route and its RTF_CACHE clone
both exist at the same fib6_node.  To do this, we need to prepare the
existing fib6 tree search to expect RTF_CACHE for /128 route.

Note that the fn->leaf is sorted by rt6i_metric.  Hence,
RTF_CACHE (if there is any) is always at the front.  This property
leads to the following:

1. When doing ip6_route_del(), it should honor the RTF_CACHE flag which
   the caller is used to ask for deleting clone or non-clone.
   The rtm_to_fib6_config() should also check the RTM_F_CLONED and
   then set RTF_CACHE accordingly so that:
   - 'ip -6 r del...' will make ip6_route_del() to delete a route
     and all its clones. Note that its clones is flushed by fib6_del()
   - 'ip -6 r flush table cache' will make ip6_route_del() to
      only delete clone(s).

2. Exclude RTF_CACHE from addrconf_get_prefix_route() which
   should not configure on a cloned route.

3. No change is need for rt6_device_match() since it currently could
   return a RTF_CACHE clone route, so the later bug-fix patch will not
   affect it.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 355b590c

net/ipv6/addrconf.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2121,6 +2121,8 @@ static struct rt6_info addrconf_get_prefix_route(const struct in6_addr pfx,
		fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0);
		if (!fn)
		goto out;

		noflags \|= RTF_CACHE;
		for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
		if (rt->dst.dev->ifindex != dev->ifindex)
		continue;

net/ipv6/route.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1785,6 +1785,9 @@ static int ip6_route_del(struct fib6_config *cfg)

		if (fn) {
		for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
		if ((rt->rt6i_flags & RTF_CACHE) &&
		!(cfg->fc_flags & RTF_CACHE))
		continue;
		if (cfg->fc_ifindex &&
		(!rt->dst.dev \|\|
		rt->dst.dev->ifindex != cfg->fc_ifindex))
		@@ -2433,6 +2436,9 @@ static int rtm_to_fib6_config(struct sk_buff skb, struct nlmsghdr nlh,
		if (rtm->rtm_type == RTN_LOCAL)
		cfg->fc_flags \|= RTF_LOCAL;

		if (rtm->rtm_flags & RTM_F_CLONED)
		cfg->fc_flags \|= RTF_CACHE;

		cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
		cfg->fc_nlinfo.nlh = nlh;
		cfg->fc_nlinfo.nl_net = sock_net(skb->sk);

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