ipv6: sysctl to restrict candidate source addresses

Per RFC 6724, section 4, "Candidate Source Addresses":

    It is RECOMMENDED that the candidate source addresses be the set
    of unicast addresses assigned to the interface that will be used
    to send to the destination (the "outgoing" interface).

Add a sysctl to enable this behaviour.

Signed-off-by: Erik Kline <ek@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 1319a6bb6b82..06ed637225b8 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -57,6 +57,7 @@ struct ipv6_devconf {
                 bool initialized;
                 struct in6_addr secret;
         } stable_secret;
+        __s32           use_oif_addrs_only;
         void            *sysctl;
 };
 
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 5efa54ae567c..641a146ead7d 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -171,6 +171,7 @@ enum {
         DEVCONF_USE_OPTIMISTIC,
         DEVCONF_ACCEPT_RA_MTU,
         DEVCONF_STABLE_SECRET,
+        DEVCONF_USE_OIF_ADDRS_ONLY,
         DEVCONF_MAX
 };