xfrm: Add basic infrastructure to support IPsec extended sequence numbers

This patch adds the struct xfrm_replay_state_esn which will be
used to support IPsec extended sequence numbers and anti replay windows
bigger than 32 packets. Also we add a function that returns the actual
size of the xfrm_replay_state_esn, a xfrm netlink atribute and a xfrm state
flag for the use of extended sequence numbers.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/xfrm.h b/include/linux/xfrm.h
index b93d6f598085..22e61fdf75a2 100644
--- a/include/linux/xfrm.h
+++ b/include/linux/xfrm.h
@@ -84,6 +84,16 @@ struct xfrm_replay_state {
         __u32   bitmap;
 };
 
+struct xfrm_replay_state_esn {
+        unsigned int    bmp_len;
+        __u32           oseq;
+        __u32           seq;
+        __u32           oseq_hi;
+        __u32           seq_hi;
+        __u32           replay_window;
+        __u32           bmp[0];
+};
+
 struct xfrm_algo {
         char            alg_name[64];
         unsigned int    alg_key_len;    /* in bits */
@@ -284,6 +294,7 @@ enum xfrm_attr_type_t {
         XFRMA_ALG_AUTH_TRUNC,   /* struct xfrm_algo_auth */
         XFRMA_MARK,             /* struct xfrm_mark */
         XFRMA_TFCPAD,           /* __u32 */
+        XFRMA_REPLAY_ESN_VAL,   /* struct xfrm_replay_esn */
         __XFRMA_MAX
 
 #define XFRMA_MAX (__XFRMA_MAX - 1)
@@ -351,6 +362,7 @@ struct xfrm_usersa_info {
 #define XFRM_STATE_ICMP         16
 #define XFRM_STATE_AF_UNSPEC    32
 #define XFRM_STATE_ALIGN4       64
+#define XFRM_STATE_ESN          128
 };
 
 struct xfrm_usersa_id {
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 8f8bd82606bf..7640822bc515 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -186,9 +186,11 @@ struct xfrm_state {
 
         /* State for replay detection */
         struct xfrm_replay_state replay;
+        struct xfrm_replay_state_esn *replay_esn;
 
         /* Replay detection state at the time we sent the last notification */
         struct xfrm_replay_state preplay;
+        struct xfrm_replay_state_esn *preplay_esn;
 
         /* internal flag that only holds state for delayed aevent at the
          * moment
@@ -1569,6 +1571,11 @@ static inline int xfrm_alg_auth_len(const struct xfrm_algo_auth *alg)
         return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
 }
 
+static inline int xfrm_replay_state_esn_len(struct xfrm_replay_state_esn *replay_esn)
+{
+        return sizeof(*replay_esn) + replay_esn->bmp_len * sizeof(__u32);
+}
+
 #ifdef CONFIG_XFRM_MIGRATE
 static inline struct xfrm_algo *xfrm_algo_clone(struct xfrm_algo *orig)
 {