[IPSEC]: Add support for combined mode algorithms

This patch adds support for combined mode algorithms with GCM being
the first algorithm supported.

Combined mode algorithms can be added through the xfrm_user interface
using the new algorithm payload type XFRMA_ALG_AEAD.  Each algorithms
is identified by its name and the ICV length.

For the purposes of matching algorithms in xfrm_tmpl structures,
combined mode algorithms occupy the same name space as encryption
algorithms.  This is in line with how they are negotiated using IKE.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/pfkeyv2.h b/include/linux/pfkeyv2.h
index d9db5f6..6db69ff 100644
--- a/include/linux/pfkeyv2.h
+++ b/include/linux/pfkeyv2.h
@@ -298,6 +298,12 @@
 #define SADB_X_EALG_BLOWFISHCBC		7
 #define SADB_EALG_NULL			11
 #define SADB_X_EALG_AESCBC		12
+#define SADB_X_EALG_AES_CCM_ICV8	14
+#define SADB_X_EALG_AES_CCM_ICV12	15
+#define SADB_X_EALG_AES_CCM_ICV16	16
+#define SADB_X_EALG_AES_GCM_ICV8	18
+#define SADB_X_EALG_AES_GCM_ICV12	19
+#define SADB_X_EALG_AES_GCM_ICV16	20
 #define SADB_X_EALG_CAMELLIACBC		22
 #define SADB_EALG_MAX                   253 /* last EALG */
 /* private allocations should use 249-255 (RFC2407) */