Commit 367efcb9 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by David S. Miller
Browse files

ipv6: Avoid redoing fib6_lookup() with reachable = 0 by saving fn 



This patch save the fn before doing rt6_backtrack.
Hence, without redo-ing the fib6_lookup(), saved_fn can be used
to redo rt6_select() with RT6_LOOKUP_F_REACHABLE off.

Some minor changes I think make sense to review as a single patch:
* Remove the 'out:' goto label.
* Remove the 'reachable' variable. Only use the 'strict' variable instead.

After this patch, "failing ip6_ins_rt()" should be the only case that
requires a redo of fib6_lookup().

Cc: David Miller <davem@davemloft.net>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 94c77bb4

net/ipv6/route.c

+16 −14
Original line number Diff line number Diff line
@@ -917,31 +917,40 @@ static struct rt6_info *rt6_alloc_clone(struct rt6_info *ort, 
static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, int oif,

				      struct flowi6 *fl6, int flags)

{

	struct fib6_node *fn;

	struct fib6_node *fn, *saved_fn;

	struct rt6_info *rt, *nrt;

	int strict = 0;

	int attempts = 3;

	int err;

	int reachable = net->ipv6.devconf_all->forwarding ? 0 : RT6_LOOKUP_F_REACHABLE;



	strict |= flags & RT6_LOOKUP_F_IFACE;

	if (net->ipv6.devconf_all->forwarding == 0)

		strict |= RT6_LOOKUP_F_REACHABLE;



redo_fib6_lookup_lock:

	read_lock_bh(&table->tb6_lock);



redo_fib6_lookup:

	fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);

	saved_fn = fn;



redo_rt6_select:

	rt = rt6_select(fn, oif, strict | reachable);

	rt = rt6_select(fn, oif, strict);

	if (rt->rt6i_nsiblings)

		rt = rt6_multipath_select(rt, fl6, oif, strict | reachable);

		rt = rt6_multipath_select(rt, fl6, oif, strict);

	if (rt == net->ipv6.ip6_null_entry) {

		fn = fib6_backtrack(fn, &fl6->saddr);

		if (fn)

			goto redo_rt6_select;

		else

			goto out;

		else if (strict & RT6_LOOKUP_F_REACHABLE) {

			/* also consider unreachable route */

			strict &= ~RT6_LOOKUP_F_REACHABLE;

			fn = saved_fn;

			goto redo_rt6_select;

		} else {

			dst_hold(&rt->dst);

			read_unlock_bh(&table->tb6_lock);

			goto out2;

		}

	}



	dst_hold(&rt->dst);
@@ -977,13 +986,6 @@ redo_rt6_select: 
	ip6_rt_put(rt);

	goto redo_fib6_lookup_lock;



out:

	if (reachable) {

		reachable = 0;

		goto redo_fib6_lookup;

	}

	dst_hold(&rt->dst);

	read_unlock_bh(&table->tb6_lock);

out2:

	rt->dst.lastuse = jiffies;

	rt->dst.__use++;

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