From 607f725f6f7d5ec3759fbc16224afb60e2152a5b Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 12 Feb 2016 15:43:54 +0100
Subject: net: replace dst_cache ip6_tunnel implementation with the generic one

This also fix a potential race into the existing tunnel code, which
could lead to the wrong dst to be permanenty cached:

CPU1:					CPU2:
  <xmit on ip6_tunnel>
  <cache lookup fails>
  dst = ip6_route_output(...)
					<tunnel params are changed via nl>
					dst_cache_reset() // no effect,
							// the cache is empty
  dst_cache_set() // the wrong dst
	// is permanenty stored
	// into the cache

With the new dst implementation the above race is not possible
since the first cache lookup after dst_cache_reset will fail due
to the timestamp check

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/Kconfig | 1 +
 1 file changed, 1 insertion(+)

(limited to 'net/ipv6/Kconfig')

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 40c897515ddc..11e875ffd7ac 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -207,6 +207,7 @@ config IPV6_NDISC_NODETYPE
 config IPV6_TUNNEL
 	tristate "IPv6: IP-in-IPv6 tunnel (RFC2473)"
 	select INET6_TUNNEL
+	select DST_CACHE
 	---help---
 	  Support for IPv6-in-IPv6 and IPv4-in-IPv6 tunnels described in
 	  RFC 2473.
-- 
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