crypto, ipsec: change GCM IV handling

- nonce construction out of salt and iv is ipsec specific so it should be
handled in ipsec code

- fixes GCM unit tests

- GCM IV is constructed out of simple counter, per RFC4106 section 3.1

Change-Id: Ib7712cc9612830daa737f5171d8384f1d361bb61
Signed-off-by: Damjan Marion <damarion@cisco.com>

2 files changed, 21 insertions, 3 deletions

diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c
index af56302bafb..3aafaffe3b5 100644
--- a/src/vnet/ipsec/esp_encrypt.c
+++ b/src/vnet/ipsec/esp_encrypt.c
@@ -225,6 +225,14 @@ esp_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node,
     }
 }
 
+typedef struct
+{
+  u32 salt;
+  u64 iv;
+} __clib_packed esp_gcm_nonce_t;
+
+STATIC_ASSERT_SIZEOF (esp_gcm_nonce_t, 12);
+
 always_inline uword
 esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 		    vlib_frame_t * frame, int is_ip6, int is_tun)
@@ -235,6 +243,7 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
   u32 n_left = frame->n_vectors;
   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
+  esp_gcm_nonce_t nonces[VLIB_FRAME_SIZE], *nonce = nonces;
   u32 thread_index = vm->thread_index;
   u16 buffer_data_size = vlib_buffer_get_default_data_size (vm);
   u32 current_sa_index = ~0, current_sa_packets = 0;
@@ -439,13 +448,10 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  vnet_crypto_op_t *op;
 	  vec_add2_aligned (ptd->crypto_ops, op, 1, CLIB_CACHE_LINE_BYTES);
 	  vnet_crypto_op_init (op, sa0->crypto_enc_op_id);
-	  op->iv = payload - iv_sz;
 	  op->src = op->dst = payload;
 	  op->key_index = sa0->crypto_key_index;
 	  op->len = payload_len - icv_sz;
-	  op->flags = VNET_CRYPTO_OP_FLAG_INIT_IV;
 	  op->user_data = b - bufs;
-	  op->salt = sa0->salt;
 
 	  if (ipsec_sa_is_set_IS_AEAD (sa0))
 	    {
@@ -459,6 +465,17 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
 	      op->tag = payload + op->len;
 	      op->tag_len = 16;
+
+	      u64 *iv = (u64 *) (payload - iv_sz);
+	      nonce->salt = sa0->salt;
+	      nonce->iv = *iv = clib_host_to_net_u64 (sa0->gcm_iv_counter++);
+	      op->iv = (u8 *) nonce;
+	      nonce++;
+	    }
+	  else
+	    {
+	      op->iv = payload - iv_sz;
+	      op->flags = VNET_CRYPTO_OP_FLAG_INIT_IV;
 	    }
 	}
 
diff --git a/src/vnet/ipsec/ipsec_sa.h b/src/vnet/ipsec/ipsec_sa.h
index bde09589672..661b54a6ce9 100644
--- a/src/vnet/ipsec/ipsec_sa.h
+++ b/src/vnet/ipsec/ipsec_sa.h
@@ -167,6 +167,7 @@ typedef struct
 
   /* Salt used in GCM modes - stored in network byte order */
   u32 salt;
+  u64 gcm_iv_counter;
 } ipsec_sa_t;
 
 STATIC_ASSERT_OFFSET_OF (ipsec_sa_t, cacheline1, CLIB_CACHE_LINE_BYTES);