[IPV6] ADDRCONF: Optimistic Duplicate Address Detection (RFC 4429) Support.

Nominally an autoconfigured IPv6 address is added to an interface in the
Tentative state (as per RFC 2462).  Addresses in this state remain in this
state while the Duplicate Address Detection process operates on them to
determine their uniqueness on the network.  During this period, these
tentative addresses may not be used for communication, increasing the time
before a node may be able to communicate on a network.  Using Optimistic
Duplicate Address Detection, autoconfigured addresses may be used
immediately for communication on the network, as long as certain rules are
followed to avoid conflicts with other nodes during the Duplicate Address
Detection process.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/if_addr.h b/include/linux/if_addr.h
index d557e4ce9b6b..43f3bedaafd3 100644
--- a/include/linux/if_addr.h
+++ b/include/linux/if_addr.h
@@ -39,6 +39,7 @@ enum
 #define IFA_F_TEMPORARY         IFA_F_SECONDARY
 
 #define IFA_F_NODAD             0x02
+#define IFA_F_OPTIMISTIC        0x04
 #define IFA_F_HOMEADDRESS       0x10
 #define IFA_F_DEPRECATED        0x20
 #define IFA_F_TENTATIVE         0x40
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 713eb5eaa81f..e046b22a2222 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -178,6 +178,9 @@ struct ipv6_devconf {
 #endif
         __s32           proxy_ndp;
         __s32           accept_source_route;
+#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
+        __s32           optimistic_dad;
+#endif
         void            *sysctl;
 };
 
@@ -208,6 +211,7 @@ enum {
         DEVCONF_PROXY_NDP,
         __DEVCONF_OPTIMISTIC_DAD,
         DEVCONF_ACCEPT_SOURCE_ROUTE,
+        DEVCONF_OPTIMISTIC_DAD,
         DEVCONF_MAX
 };