iv_gen: Provide external sequence number (IKE, ESP)

This prevents duplicate sequential IVs in case of a HA failover.

src/libcharon/encoding/payloads/encryption_payload.c

@@ -309,7 +309,7 @@ static chunk_t append_header(private_encryption_payload_t *this, chunk_t assoc)
 }
 
 METHOD(encryption_payload_t, encrypt, status_t,
-	private_encryption_payload_t *this, chunk_t assoc)
+	private_encryption_payload_t *this, u_int64_t mid, chunk_t assoc)
 {
 	chunk_t iv, plain, padding, icv, crypt;
 	generator_t *generator;
@@ -364,7 +364,7 @@ METHOD(encryption_payload_t, encrypt, status_t,
 	crypt = chunk_create(plain.ptr, plain.len + padding.len);
 	generator->destroy(generator);
 
-	if (!iv_gen->get_iv(iv_gen, iv.len, iv.ptr) ||
+	if (!iv_gen->get_iv(iv_gen, mid, iv.len, iv.ptr) ||
 		!rng->get_bytes(rng, padding.len - 1, padding.ptr))
 	{
 		DBG1(DBG_ENC, "encrypting encryption payload failed, no IV or padding");
@@ -396,7 +396,7 @@ METHOD(encryption_payload_t, encrypt, status_t,
 }
 
 METHOD(encryption_payload_t, encrypt_v1, status_t,
-	private_encryption_payload_t *this, chunk_t iv)
+	private_encryption_payload_t *this, u_int64_t mid, chunk_t iv)
 {
 	generator_t *generator;
 	chunk_t plain, padding;

src/libcharon/encoding/payloads/encryption_payload.h

@@ -71,13 +71,15 @@ struct encryption_payload_t {
 	/**
 	 * Generate, encrypt and sign contained payloads.
 	 *
+	 * @param mid			message ID
 	 * @param assoc			associated data
 	 * @return
 	 * 						- SUCCESS if encryption successful
 	 * 						- FAILED if encryption failed
 	 * 						- INVALID_STATE if aead not supplied, but needed
 	 */
-	status_t (*encrypt) (encryption_payload_t *this, chunk_t assoc);
+	status_t (*encrypt) (encryption_payload_t *this, u_int64_t mid,
+						 chunk_t assoc);
 
 	/**
 	 * Decrypt, verify and parse contained payloads.