[IPSEC] xfrm: Abstract out encapsulation modes

This patch adds the structure xfrm_mode.  It is meant to represent
the operations carried out by transport/tunnel modes.

By doing this we allow additional encapsulation modes to be added
without clogging up the xfrm_input/xfrm_output paths.

Candidate modes include 4-to-6 tunnel mode, 6-to-4 tunnel mode, and
BEET modes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index e40f7532237..35eb70b1448 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -414,6 +414,24 @@ config INET_TUNNEL
         tristate
         default n
 
+config INET_XFRM_MODE_TRANSPORT
+        tristate "IP: IPsec transport mode"
+        default y
+        select XFRM
+        ---help---
+          Support for IPsec transport mode.
+
+          If unsure, say Y.
+
+config INET_XFRM_MODE_TUNNEL
+        tristate "IP: IPsec tunnel mode"
+        default y
+        select XFRM
+        ---help---
+          Support for IPsec tunnel mode.
+
+          If unsure, say Y.
+
 config INET_DIAG
         tristate "INET: socket monitoring interface"
         default y