Implement the first step towards a more flexible way to support crypto methods

17 files changed, 302 insertions, 434 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e312f96..68b077e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -7,6 +7,7 @@ link_directories(${UECC_LIBRARY_DIRS} ${NACL_LIBRARY_DIRS})
 
 add_subdirectory(protocols)
 add_subdirectory(methods)
+add_subdirectory(crypto)
 
 
 BISON_TARGET(fastd_config_parse config.y ${CMAKE_CURRENT_BINARY_DIR}/config.yy.c)
@@ -16,7 +17,6 @@ add_executable(fastd
   capabilities.c
   config.c
   crypto.c
-  crypto_linux.c
   handshake.c
   hkdf_sha256.c
   lex.c
@@ -34,6 +34,7 @@ add_executable(fastd
   ${BISON_fastd_config_parse_OUTPUTS}
   ${PROTOCOL_SOURCES}
   ${METHOD_SOURCES}
+  ${CRYPTO_SOURCES}
 )
 set_property(TARGET fastd PROPERTY COMPILE_FLAGS "${FASTD_CFLAGS}")
 set_property(TARGET fastd PROPERTY LINK_FLAGS "-pthread ${UECC_LDFLAGS_OTHER} ${NACL_LDFLAGS_OTHER}")
diff --git a/src/config.c b/src/config.c
index 407ef97..8cf0dcb 100644
--- a/src/config.c
+++ b/src/config.c
@@ -43,37 +43,9 @@
 extern const fastd_protocol_t fastd_protocol_ec25519_fhmqvc;
 
 
-#ifdef USE_CRYPTO_AES128CTR
-#ifdef WITH_CRYPTO_AES128CTR_NACL
-extern const fastd_crypto_aes128ctr_t fastd_crypto_aes128ctr_nacl;
-#endif
-#ifdef WITH_CRYPTO_AES128CTR_LINUX
-extern const fastd_crypto_aes128ctr_t fastd_crypto_aes128ctr_linux;
-#endif
-
-#ifdef WITH_CRYPTO_AES128CTR_NACL
-static const fastd_crypto_aes128ctr_t *fastd_crypto_aes128ctr_default = &fastd_crypto_aes128ctr_nacl;
-#else
-static const fastd_crypto_aes128ctr_t *fastd_crypto_aes128ctr_default = &fastd_crypto_aes128ctr_linux;
-#endif
-
-#endif
-
 #ifdef USE_CRYPTO_GHASH
-#ifdef WITH_CRYPTO_GHASH_BUILTIN
 extern const fastd_crypto_ghash_t fastd_crypto_ghash_builtin;
 #endif
-#ifdef WITH_CRYPTO_GHASH_LINUX
-extern const fastd_crypto_ghash_t fastd_crypto_ghash_linux;
-#endif
-
-#ifdef WITH_CRYPTO_GHASH_BUILTIN
-static const fastd_crypto_ghash_t *fastd_crypto_ghash_default = &fastd_crypto_ghash_builtin;
-#else
-static const fastd_crypto_ghash_t *fastd_crypto_ghash_default = &fastd_crypto_ghash_linux;
-#endif
-
-#endif
 
 static void default_config(fastd_config_t *conf) {
 	memset(conf, 0, sizeof(fastd_config_t));
@@ -102,16 +74,15 @@ static void default_config(fastd_config_t *conf) {
 	conf->key_refresh = 3300;	/* 55 minutes */
 	conf->key_refresh_splay = 300;	/* 5 minutes */
 
-#ifdef USE_CRYPTO_AES128CTR
-	conf->crypto_aes128ctr = fastd_crypto_aes128ctr_default;
-#endif
 #ifdef USE_CRYPTO_GHASH
-	conf->crypto_ghash = fastd_crypto_ghash_default;
+	conf->crypto_ghash = &fastd_crypto_ghash_builtin;
 #endif
 
 	conf->peer_group = calloc(1, sizeof(fastd_peer_group_config_t));
 	conf->peer_group->name = strdup("default");
 	conf->peer_group->max_connections = -1;
+
+	conf->ciphers = fastd_cipher_config_alloc();
 }
 
 bool fastd_config_protocol(fastd_context_t *ctx UNUSED, fastd_config_t *conf, const char *name) {
@@ -142,37 +113,12 @@ bool fastd_config_method(fastd_context_t *ctx, fastd_config_t *conf, const char
 }
 
 bool fastd_config_crypto(fastd_context_t *ctx UNUSED, fastd_config_t *conf UNUSED, const char *alg UNUSED, const char *impl UNUSED) {
-#ifdef USE_CRYPTO_AES128CTR
-	if (!strcasecmp(alg, "aes128-ctr") || !strcasecmp(alg, "aes128") || !strcasecmp(alg, "aes-ctr") || !strcasecmp(alg, "aes")) {
-		if (!strcasecmp(impl, "default"))
-			conf->crypto_aes128ctr = fastd_crypto_aes128ctr_default;
-#ifdef WITH_CRYPTO_AES128CTR_NACL
-		else if (!strcasecmp(impl, "nacl"))
-			conf->crypto_aes128ctr = &fastd_crypto_aes128ctr_nacl;
-#endif
-#ifdef WITH_CRYPTO_AES128CTR_LINUX
-		else if (!strcasecmp(impl, "linux"))
-			conf->crypto_aes128ctr = &fastd_crypto_aes128ctr_linux;
-#endif
-		else
-			return false;
-
-		return true;
-	}
-	else
-#endif
 #ifdef USE_CRYPTO_GHASH
 	if (!strcasecmp(alg, "ghash")) {
 		if (!strcasecmp(impl, "default"))
-			conf->crypto_ghash = fastd_crypto_ghash_default;
-#ifdef WITH_CRYPTO_GHASH_BUILTIN
+			conf->crypto_ghash = &fastd_crypto_ghash_builtin;
 		else if (!strcasecmp(impl, "builtin"))
 			conf->crypto_ghash = &fastd_crypto_ghash_builtin;
-#endif
-#ifdef WITH_CRYPTO_GHASH_LINUX
-		else if (!strcasecmp(impl, "linux"))
-			conf->crypto_ghash = &fastd_crypto_ghash_linux;
-#endif
 		else
 			return false;
 
@@ -725,6 +671,8 @@ void fastd_config_release(fastd_context_t *ctx, fastd_config_t *conf) {
 
 	fastd_string_stack_free(conf->methods);
 
+	fastd_cipher_config_free(conf->ciphers);
+
 	free(conf->user);
 	free(conf->group);
 	free(conf->groups);
diff --git a/src/config.y b/src/config.y
index bb9884e..ffc719d 100644
--- a/src/config.y
+++ b/src/config.y
@@ -128,8 +128,6 @@
 	#include <peer.h>
 
 	#include <limits.h>
-	#include <stdint.h>
-	#include <unistd.h>
 
 	void fastd_config_error(YYLTYPE *loc, fastd_context_t *ctx, fastd_config_t *conf, const char *filename, int depth, const char *s);
 }
diff --git a/src/crypto.c b/src/crypto.c
index 802c5da..1583349 100644
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -28,59 +28,6 @@
 #include "crypto.h"
 
 
-#ifdef USE_CRYPTO_AES128CTR
-#ifdef WITH_CRYPTO_AES128CTR_NACL
-
-#include <crypto_stream_aes128ctr.h>
-
-
-struct fastd_crypto_aes128ctr_state {
-	fastd_buffer_t d;
-};
-
-
-static fastd_crypto_aes128ctr_context_t* aes128ctr_init(fastd_context_t *ctx UNUSED) {
-	return (fastd_crypto_aes128ctr_context_t*)1;
-}
-
-static fastd_crypto_aes128ctr_state_t* aes128ctr_set_key(fastd_context_t *ctx, const fastd_crypto_aes128ctr_context_t *cctx UNUSED, const fastd_block128_t *key) {
-	fastd_crypto_aes128ctr_state_t *cstate = malloc(sizeof(fastd_crypto_aes128ctr_state_t));
-
-	cstate->d = fastd_buffer_alloc(ctx, crypto_stream_aes128ctr_BEFORENMBYTES, 0, 0);
-	crypto_stream_aes128ctr_beforenm(cstate->d.data, key->b);
-
-	return cstate;
-}
-
-static bool aes128ctr_crypt(fastd_context_t *ctx UNUSED, const fastd_crypto_aes128ctr_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv) {
-	crypto_stream_aes128ctr_xor_afternm(out->b, in->b, len, iv->b, cstate->d.data);
-	return true;
-}
-
-static void aes128ctr_free_state(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_state_t *cstate) {
-	if (cstate) {
-		fastd_buffer_free(cstate->d);
-		free(cstate);
-	}
-}
-
-static void aes128ctr_free(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_context_t *cctx UNUSED) {
-}
-
-const fastd_crypto_aes128ctr_t fastd_crypto_aes128ctr_nacl = {
-	.name = "nacl",
-
-	.init = aes128ctr_init,
-	.set_key = aes128ctr_set_key,
-	.crypt = aes128ctr_crypt,
-
-	.free_state = aes128ctr_free_state,
-	.free = aes128ctr_free,
-};
-
-#endif
-#endif
-
 #ifdef USE_CRYPTO_GHASH
 #ifdef WITH_CRYPTO_GHASH_BUILTIN
 
diff --git a/src/crypto.h b/src/crypto.h
index 7894f85..b954651 100644
--- a/src/crypto.h
+++ b/src/crypto.h
@@ -29,27 +29,6 @@
 
 #include "types.h"
 
-#include <stdint.h>
-
-
-typedef union fastd_block128 {
-	uint8_t b[16];
-	uint64_t qw[2];
-} __attribute__((aligned(16))) fastd_block128_t;
-
-
-#ifdef USE_CRYPTO_AES128CTR
-struct fastd_crypto_aes128ctr {
-	const char *name;
-
-	fastd_crypto_aes128ctr_context_t* (*init)(fastd_context_t *ctx);
-	fastd_crypto_aes128ctr_state_t* (*set_key)(fastd_context_t *ctx, const fastd_crypto_aes128ctr_context_t *cctx, const fastd_block128_t *key);
-	bool (*crypt)(fastd_context_t *ctx, const fastd_crypto_aes128ctr_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv);
-
-	void (*free_state)(fastd_context_t *ctx, fastd_crypto_aes128ctr_state_t *cstate);
-	void (*free)(fastd_context_t *ctx, fastd_crypto_aes128ctr_context_t *cctx);
-};
-#endif
 
 #ifdef USE_CRYPTO_GHASH
 struct fastd_crypto_ghash {
diff --git a/src/crypto/CMakeLists.txt b/src/crypto/CMakeLists.txt
new file mode 100644
index 0000000..1c78e03
--- /dev/null
+++ b/src/crypto/CMakeLists.txt
@@ -0,0 +1,3 @@
+add_subdirectory(cipher)
+
+set(CRYPTO_SOURCES "${CIPHER_SOURCES}" PARENT_SCOPE)
diff --git a/src/crypto/cipher/CMakeLists.txt b/src/crypto/cipher/CMakeLists.txt
new file mode 100644
index 0000000..00b8560
--- /dev/null
+++ b/src/crypto/cipher/CMakeLists.txt
@@ -0,0 +1,34 @@
+set(CIPHERS "")
+
+if(WITH_CIPHER_AES128_CTR)
+  list(APPEND CIPHERS aes128_ctr)
+endif(WITH_CIPHER_AES128_CTR)
+
+set(CIPHER_SOURCES "${CMAKE_CURRENT_BINARY_DIR}/ciphers.c")
+
+set(CIPHER_DEFINITIONS "")
+set(CIPHER_IMPLS "")
+set(CIPHER_LIST "")
+
+foreach(cipher ${CIPHERS})
+  add_subdirectory(${cipher})
+
+  list(APPEND CIPHER_SOURCES ${IMPL_SOURCES})
+
+  set(CIPHER_LIST "${CIPHER_LIST}\n{\"${CIPHER_NAME}\", cipher_${cipher}_impls},")
+  set(CIPHER_IMPLS "${CIPHER_IMPLS}\nstatic const fastd_cipher_t *const cipher_${cipher}_impls[] = {")
+
+  foreach(impl ${IMPLS})
+    set(CIPHER_DEFINITIONS "${CIPHER_DEFINITIONS}\nextern const fastd_cipher_t fastd_cipher_${cipher}_${impl};")
+    set(CIPHER_IMPLS "${CIPHER_IMPLS}&fastd_cipher_${cipher}_${impl}, ")
+  endforeach(impl)
+
+  set(CIPHER_IMPLS "${CIPHER_IMPLS}NULL};")
+
+endforeach(cipher)
+
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/ciphers.c.in ${CMAKE_CURRENT_BINARY_DIR}/ciphers.c)
+
+
+set(CIPHER_SOURCES "${CIPHER_SOURCES}" PARENT_SCOPE)
diff --git a/src/crypto/cipher/aes128_ctr/CMakeLists.txt b/src/crypto/cipher/aes128_ctr/CMakeLists.txt
new file mode 100644
index 0000000..6237a7c
--- /dev/null
+++ b/src/crypto/cipher/aes128_ctr/CMakeLists.txt
@@ -0,0 +1,18 @@
+set(IMPLS "")
+
+if(WITH_CIPHER_AES128_CTR_NACL)
+  list(APPEND IMPLS nacl)
+endif(WITH_CIPHER_AES128_CTR_NACL)
+
+set(IMPL_SOURCES "")
+
+foreach(impl ${IMPLS})
+  add_subdirectory(${impl})
+
+  list(APPEND IMPL_SOURCES $<TARGET_OBJECTS:cipher_aes128_ctr_${impl}>)
+endforeach(impl)
+
+
+set(CIPHER_NAME "aes128-ctr" PARENT_SCOPE)
+set(IMPLS "${IMPLS}" PARENT_SCOPE)
+set(IMPL_SOURCES "${IMPL_SOURCES}" PARENT_SCOPE)
diff --git a/src/crypto/cipher/aes128_ctr/nacl/CMakeLists.txt b/src/crypto/cipher/aes128_ctr/nacl/CMakeLists.txt
new file mode 100644
index 0000000..50e4b4c
--- /dev/null
+++ b/src/crypto/cipher/aes128_ctr/nacl/CMakeLists.txt
@@ -0,0 +1,6 @@
+include_directories(${FASTD_SOURCE_DIR}/src ${FASTD_BINARY_DIR} ${NACL_INCLUDE_DIRS})
+
+add_library(cipher_aes128_ctr_nacl OBJECT
+  cipher_aes128_ctr_nacl.c
+)
+set_property(TARGET method_xsalsa20_poly1305 PROPERTY COMPILE_FLAGS "${FASTD_CFLAGS}")
diff --git a/src/crypto/cipher/aes128_ctr/nacl/cipher_aes128_ctr_nacl.c b/src/crypto/cipher/aes128_ctr/nacl/cipher_aes128_ctr_nacl.c
new file mode 100644
index 0000000..f63e46f
--- /dev/null
+++ b/src/crypto/cipher/aes128_ctr/nacl/cipher_aes128_ctr_nacl.c
@@ -0,0 +1,76 @@
+/*
+  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include "../../../../fastd.h"
+#include <crypto_stream_aes128ctr.h>
+
+
+struct fastd_cipher_state {
+	fastd_buffer_t d;
+};
+
+
+static fastd_cipher_context_t* aes128_ctr_initialize(fastd_context_t *ctx UNUSED) {
+	return NULL;
+}
+
+static fastd_cipher_state_t* aes128_ctr_init_state(fastd_context_t *ctx, const fastd_cipher_context_t *cctx UNUSED, const uint8_t *key) {
+	fastd_block128_t k;
+	memcpy(k.b, key, sizeof(fastd_block128_t));
+
+	fastd_cipher_state_t *state = malloc(sizeof(fastd_cipher_state_t));
+
+	state->d = fastd_buffer_alloc(ctx, crypto_stream_aes128ctr_BEFORENMBYTES, 0, 0);
+	crypto_stream_aes128ctr_beforenm(state->d.data, k.b);
+
+	return state;
+}
+
+static bool aes128_ctr_crypt(fastd_context_t *ctx UNUSED, const fastd_cipher_state_t *state, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv) {
+	crypto_stream_aes128ctr_xor_afternm(out->b, in->b, len, iv->b, state->d.data);
+	return true;
+}
+
+static void aes128_ctr_free_state(fastd_context_t *ctx UNUSED, fastd_cipher_state_t *state) {
+	if (state) {
+		fastd_buffer_free(state->d);
+		free(state);
+	}
+}
+
+static void aes128_ctr_free(fastd_context_t *ctx UNUSED, fastd_cipher_context_t *cctx UNUSED) {
+}
+
+const fastd_cipher_t fastd_cipher_aes128_ctr_nacl = {
+	.name = "nacl",
+
+	.initialize = aes128_ctr_initialize,
+	.init_state = aes128_ctr_init_state,
+	.crypt = aes128_ctr_crypt,
+
+	.free_state = aes128_ctr_free_state,
+	.free = aes128_ctr_free,
+};
diff --git a/src/crypto/cipher/ciphers.c.in b/src/crypto/cipher/ciphers.c.in
new file mode 100644
index 0000000..ee710f8
--- /dev/null
+++ b/src/crypto/cipher/ciphers.c.in
@@ -0,0 +1,103 @@
+/*
+  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include <fastd.h>
+
+
+@CIPHER_DEFINITIONS@
+
+typedef struct cipher_impl_list {
+	const char *name;
+	const fastd_cipher_t *const *impls;
+} cipher_impl_list_t;
+
+@CIPHER_IMPLS@
+
+static const cipher_impl_list_t ciphers[] = { @CIPHER_LIST@
+};
+
+
+const fastd_cipher_t** fastd_cipher_config_alloc(void) {
+	const fastd_cipher_t **cipher_conf = calloc(array_size(ciphers), sizeof(const fastd_cipher_t*));
+
+	size_t i;
+	for (i = 0; i < array_size(ciphers); i++)
+		cipher_conf[i] = ciphers[i].impls[0];
+
+	return cipher_conf;
+}
+
+void fastd_cipher_config_free(const fastd_cipher_t **cipher_conf) {
+	free(cipher_conf);
+}
+
+bool fastd_cipher_config(const fastd_cipher_t **cipher_conf, const char *name, const char *impl) {
+	size_t i;
+	for (i = 0; i < array_size(ciphers); i++) {
+		if (!strcmp(ciphers[i].name, name)) {
+			size_t j;
+			for (j = 0; ciphers[i].impls[j]; j++) {
+				if (!strcmp(ciphers[i].impls[j]->name, impl)) {
+					cipher_conf[i] = ciphers[i].impls[j];
+					return true;
+				}
+			}
+
+			return false;
+		}
+	}
+
+	return false;
+}
+
+void fastd_cipher_init(fastd_context_t *ctx) {
+	ctx->cipher_contexts = calloc(array_size(ciphers), sizeof(fastd_cipher_context_t*));
+
+	size_t i;
+	for (i = 0; i < array_size(ciphers); i++)
+		ctx->cipher_contexts[i] = ctx->conf->ciphers[i]->initialize(ctx);
+}
+
+void fastd_cipher_free(fastd_context_t *ctx) {
+	size_t i;
+	for (i = 0; i < array_size(ciphers); i++)
+		ctx->conf->ciphers[i]->free(ctx, ctx->cipher_contexts[i]);
+
+	free(ctx->cipher_contexts);
+}
+
+bool fastd_cipher_get_by_name(fastd_context_t *ctx, const char *name, const fastd_cipher_t **cipher, fastd_cipher_context_t **cctx) {
+	size_t i;
+	for (i = 0; i < array_size(ciphers); i++) {
+		if (!strcmp(ciphers[i].name, name)) {
+			*cipher = ctx->conf->ciphers[i];
+			*cctx = ctx->cipher_contexts[i];
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/src/crypto_linux.c b/src/crypto_linux.c
deleted file mode 100644
index 2cd7145..0000000
--- a/src/crypto_linux.c
+++ /dev/null
@@ -1,262 +0,0 @@
-/*
-  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
-  All rights reserved.
-
-  Redistribution and use in source and binary forms, with or without
-  modification, are permitted provided that the following conditions are met:
-
-    1. Redistributions of source code must retain the above copyright notice,
-       this list of conditions and the following disclaimer.
-    2. Redistributions in binary form must reproduce the above copyright notice,
-       this list of conditions and the following disclaimer in the documentation
-       and/or other materials provided with the distribution.
-
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*/
-
-
-#include "fastd.h"
-#include "crypto.h"
-
-
-#if (defined(USE_CRYPTO_AES128CTR) && defined(WITH_CRYPTO_AES128CTR_LINUX)) || (defined(USE_CRYPTO_GHASH) && defined(WITH_CRYPTO_GHASH_LINUX))
-
-#include <alloca.h>
-#include <linux/if_alg.h>
-
-#ifndef SOL_ALG
-#define SOL_ALG 279
-#endif
-
-#endif
-
-
-#ifdef USE_CRYPTO_AES128CTR
-#ifdef WITH_CRYPTO_AES128CTR_LINUX
-
-struct fastd_crypto_aes128ctr_context {
-	int fd;
-};
-
-struct fastd_crypto_aes128ctr_state {
-	int fd;
-};
-
-static fastd_crypto_aes128ctr_context_t* aes128ctr_init(fastd_context_t *ctx) {
-	int fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
-	if (fd < 0)
-		goto error;
-
-	struct sockaddr_alg sa = {};
-	sa.salg_family = AF_ALG;
-	strcpy((char*)sa.salg_type, "skcipher");
-	strcpy((char*)sa.salg_name, "ctr(aes)");
-	if (bind(fd, (struct sockaddr*)&sa, sizeof(sa)) < 0)
-		goto error;
-
-	fastd_crypto_aes128ctr_context_t *cctx = malloc(sizeof(fastd_crypto_aes128ctr_context_t));
-	cctx->fd = fd;
-	return cctx;
-
- error:
-	if (fd >= 0)
-		close(fd);
-
-	pr_error(ctx, "no kernel support for AES-CTR was found");
-	return NULL;
-}
-
-static fastd_crypto_aes128ctr_state_t* aes128ctr_set_key(fastd_context_t *ctx, const fastd_crypto_aes128ctr_context_t *cctx, const fastd_block128_t *key) {
-	if (setsockopt(cctx->fd, SOL_ALG, ALG_SET_KEY, key->b, 16) < 0) {
-		pr_error_errno(ctx, "aes128ctr_set_key(linux): setsockopt");
-		return NULL;
-	}
-
-	int fd = accept(cctx->fd, NULL, NULL);
-
-	if (fd < 0) {
-		pr_error_errno(ctx, "aes128ctr_set_key(linux): accept");
-		return NULL;
-	}
-
-	fastd_crypto_aes128ctr_state_t *cstate = malloc(sizeof(fastd_crypto_aes128ctr_state_t));
-	cstate->fd = fd;
-
-	return cstate;
-}
-
-static bool aes128ctr_crypt(fastd_context_t *ctx, const fastd_crypto_aes128ctr_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv) {
-	if (!len)
-		return false;
-
-	struct iovec vec = { .iov_base = (void*)in, .iov_len = len };
-
-	static const size_t cmsglen = sizeof(struct cmsghdr)+sizeof(struct af_alg_iv)+16;
-	struct cmsghdr *cmsg = alloca(cmsglen);
-	cmsg->cmsg_len = cmsglen;
-	cmsg->cmsg_level = SOL_ALG;
-	cmsg->cmsg_type = ALG_SET_IV;
-
-	struct af_alg_iv *alg_iv = (void*)CMSG_DATA(cmsg);
-	alg_iv->ivlen = 16;
-	memcpy(alg_iv->iv, iv, 16);
-
-	struct msghdr msg = {
-		.msg_iov = &vec,
-		.msg_iovlen = 1,
-		.msg_control = cmsg,
-		.msg_controllen = cmsglen
-	};
-
-	if (sendmsg(cstate->fd, &msg, 0) < 0) {
-		pr_error_errno(ctx, "aes128ctr_crypt(linux): sendmsg");
-		return false;
-	}
-
-	msg.msg_control = NULL;
-	msg.msg_controllen = 0;
-	vec.iov_base = out;
-
-	if (recvmsg(cstate->fd, &msg, 0) < 0) {
-		pr_error_errno(ctx, "aes128ctr_crypt(linux): recvmsg");
-		return false;
-	}
-
-	return true;
-}
-
-static void aes128ctr_free_state(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_state_t *cstate) {
-	if (cstate) {
-		close(cstate->fd);
-		free(cstate);
-	}
-}
-
-static void aes128ctr_free(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_context_t *cctx) {
-	if (cctx) {
-		close(cctx->fd);
-		free(cctx);
-	}
-}
-
-const fastd_crypto_aes128ctr_t fastd_crypto_aes128ctr_linux = {
-	.name = "linux",
-
-	.init = aes128ctr_init,
-	.set_key = aes128ctr_set_key,
-	.crypt = aes128ctr_crypt,
-
-	.free_state = aes128ctr_free_state,
-	.free = aes128ctr_free,
-};
-
-#endif
-#endif
-
-#ifdef USE_CRYPTO_GHASH
-#ifdef WITH_CRYPTO_GHASH_LINUX
-
-struct fastd_crypto_ghash_context {
-	int fd;
-};
-
-struct fastd_crypto_ghash_state {
-	int fd;
-};
-
-static fastd_crypto_ghash_context_t* ghash_init(fastd_context_t *ctx) {
-	int fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
-	if (fd < 0)
-		goto error;
-
-	struct sockaddr_alg sa = {};
-	sa.salg_family = AF_ALG;
-	strcpy((char*)sa.salg_type, "hash");
-	strcpy((char*)sa.salg_name, "ghash");
-	if (bind(fd, (struct sockaddr*)&sa, sizeof(sa)) < 0)
-		goto error;
-
-	fastd_crypto_ghash_context_t *cctx = malloc(sizeof(fastd_crypto_ghash_context_t));
-	cctx->fd = fd;
-	return cctx;
-
- error:
-	if (fd >= 0)
-		close(fd);
-
-	pr_error(ctx, "no kernel support for GHASH was found");
-	return NULL;
-}
-
-static fastd_crypto_ghash_state_t* ghash_set_h(fastd_context_t *ctx, const fastd_crypto_ghash_context_t *cctx, const fastd_block128_t *h) {
-	if (setsockopt(cctx->fd, SOL_ALG, ALG_SET_KEY, h, 16) < 0) {
-		pr_error_errno(ctx, "ghash_set_h(linux): setsockopt");
-		return NULL;
-	}
-
-	int fd = accept(cctx->fd, NULL, NULL);
-
-	if (fd < 0) {
-		pr_error_errno(ctx, "ghash_set_h(linux): accept");
-		return NULL;
-	}
-
-	fastd_crypto_ghash_state_t *cstate = malloc(sizeof(fastd_crypto_ghash_state_t));
-	cstate->fd = fd;
-
-	return cstate;
-}
-
-static bool ghash_hash(fastd_context_t *ctx, const fastd_crypto_ghash_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t n_blocks) {
-	if (!n_blocks)
-		return false;
-
-	if (write(cstate->fd, in, n_blocks*16) < 0) {
-		pr_error_errno(ctx, "ghash_hash(linux): write");
-		return false;
-	}
-
-	if (read(cstate->fd, out, 16) < 16) {
-		pr_error_errno(ctx, "ghash_hash(linux): read");
-		return false;
-	}
-
-	return true;
-}
-
-static void ghash_free_state(fastd_context_t *ctx UNUSED, fastd_crypto_ghash_state_t *cstate) {
-	if (cstate) {
-		close(cstate->fd);
-		free(cstate);
-	}
-}
-
-static void ghash_free(fastd_context_t *ctx UNUSED, fastd_crypto_ghash_context_t *cctx) {
-	if (cctx) {
-		close(cctx->fd);
-		free(cctx);
-	}
-}
-
-const fastd_crypto_ghash_t fastd_crypto_ghash_linux = {
-	.name = "linux",
-
-	.init = ghash_init,
-	.set_h = ghash_set_h,
-	.hash = ghash_hash,
-
-	.free_state = ghash_free_state,
-	.free = ghash_free,
-};
-
-#endif
-#endif
diff --git a/src/fastd.c b/src/fastd.c
index ea197d3..534a30e 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -145,12 +145,8 @@ static void close_log(fastd_context_t *ctx) {
 	closelog();
 }
 
-static void crypto_init(fastd_context_t *ctx UNUSED) {
-#ifdef USE_CRYPTO_AES128CTR
-	ctx->crypto_aes128ctr = ctx->conf->crypto_aes128ctr->init(ctx);
-	if (!ctx->crypto_aes128ctr)
-		exit_error(ctx, "Unable to initialize AES128-CTR implementation");
-#endif
+static void crypto_init(fastd_context_t *ctx) {
+	fastd_cipher_init(ctx);
 
 #ifdef USE_CRYPTO_GHASH
 	ctx->crypto_ghash = ctx->conf->crypto_ghash->init(ctx);
@@ -160,15 +156,12 @@ static void crypto_init(fastd_context_t *ctx UNUSED) {
 }
 
 static void crypto_free(fastd_context_t *ctx UNUSED) {
-#ifdef USE_CRYPTO_AES128CTR
-	ctx->conf->crypto_aes128ctr->free(ctx, ctx->crypto_aes128ctr);
-	ctx->crypto_aes128ctr = NULL;
-#endif
-
 #ifdef USE_CRYPTO_GHASH
 	ctx->conf->crypto_ghash->free(ctx, ctx->crypto_ghash);
 	ctx->crypto_ghash = NULL;
 #endif
+
+	fastd_cipher_free(ctx);
 }
 
 
diff --git a/src/fastd.h b/src/fastd.h
index 9c168af..be4cf11 100644
--- a/src/fastd.h
+++ b/src/fastd.h
@@ -100,6 +100,17 @@ struct fastd_method {
 	bool (*decrypt)(fastd_context_t *ctx, fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in);
 };
 
+struct fastd_cipher {
+	const char *name;
+
+	fastd_cipher_context_t* (*initialize)(fastd_context_t *ctx);
+	fastd_cipher_state_t* (*init_state)(fastd_context_t *ctx, const fastd_cipher_context_t *cctx, const uint8_t *key);
+	bool (*crypt)(fastd_context_t *ctx, const fastd_cipher_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv);
+
+	void (*free_state)(fastd_context_t *ctx, fastd_cipher_state_t *cstate);
+	void (*free)(fastd_context_t *ctx, fastd_cipher_context_t *cctx);
+};
+
 union fastd_peer_address {
 	struct sockaddr sa;
 	struct sockaddr_in in;
@@ -225,9 +236,8 @@ struct fastd_config {
 	unsigned key_refresh;
 	unsigned key_refresh_splay;
 
-#ifdef USE_CRYPTO_AES128CTR
-	const fastd_crypto_aes128ctr_t *crypto_aes128ctr;
-#endif
+	const fastd_cipher_t **ciphers;
+
 #ifdef USE_CRYPTO_GHASH
 	const fastd_crypto_ghash_t *crypto_ghash;
 #endif
@@ -305,9 +315,8 @@ struct fastd_context {
 	fastd_stats_t tx_dropped;
 	fastd_stats_t tx_error;
 
-#ifdef USE_CRYPTO_AES128CTR
-	fastd_crypto_aes128ctr_context_t *crypto_aes128ctr;
-#endif
+	fastd_cipher_context_t **cipher_contexts;
+
 #ifdef USE_CRYPTO_GHASH
 	fastd_crypto_ghash_context_t *crypto_ghash;
 #endif
@@ -340,8 +349,8 @@ void fastd_socket_close(fastd_context_t *ctx, fastd_socket_t *sock);
 void fastd_socket_error(fastd_context_t *ctx, fastd_socket_t *sock);
 
 void fastd_setfd(const fastd_context_t *ctx, int fd, int set, int unset);
-void fastd_setfl(const fastd_context_t *ctx, int fd, int set, int unset);
-
+void fastd_setfl(const fastd_context_t *ctx, int fd, int set, int unset)
+;
 void fastd_resolve_peer(fastd_context_t *ctx, fastd_peer_t *peer, fastd_remote_t *remote);
 
 int fastd_vsnprintf(const fastd_context_t *ctx, char *buffer, size_t size, const char *format, va_list ap);
@@ -352,6 +361,14 @@ bool fastd_read_config(fastd_context_t *ctx, fastd_config_t *conf, const char *f
 
 const fastd_method_t* fastd_method_get_by_name(const char *name);
 
+const fastd_cipher_t** fastd_cipher_config_alloc(void);
+void fastd_cipher_config_free(const fastd_cipher_t **cipher_conf);
+bool fastd_cipher_config(const fastd_cipher_t **cipher_conf, const char *name, const char *impl);
+
+void fastd_cipher_init(fastd_context_t *ctx);
+void fastd_cipher_free(fastd_context_t *ctx);
+bool fastd_cipher_get_by_name(fastd_context_t *ctx, const char *name, const fastd_cipher_t **cipher, fastd_cipher_context_t **cctx);
+
 bool fastd_config_protocol(fastd_context_t *ctx, fastd_config_t *conf, const char *name);
 bool fastd_config_method(fastd_context_t *ctx, fastd_config_t *conf, const char *name);
 bool fastd_config_crypto(fastd_context_t *ctx, fastd_config_t *conf, const char *alg, const char *impl);
@@ -408,6 +425,7 @@ static inline int fastd_rand(fastd_context_t *ctx, int min, int max) {
 			const typeof( ((type *)0)->member ) *__mptr = (ptr); \
 			(type *)( (char *)__mptr - offsetof(type,member) );})
 
+#define array_size(array) (sizeof(array)/sizeof((array)[0]))
 
 static inline size_t block_count(size_t l, size_t a) {
 	return (l+a-1)/a;
diff --git a/src/methods/aes128_gcm/aes128_gcm.c b/src/methods/aes128_gcm/aes128_gcm.c
index 297031b..20f393f 100644
--- a/src/methods/aes128_gcm/aes128_gcm.c
+++ b/src/methods/aes128_gcm/aes128_gcm.c
@@ -32,7 +32,10 @@
 struct fastd_method_session_state {
 	fastd_method_common_t common;
 
-	fastd_crypto_aes128ctr_state_t *cstate_aes128ctr;
+	const fastd_cipher_t *aes128_ctr;
+	fastd_cipher_context_t *aes128_ctr_ctx;
+	fastd_cipher_state_t *aes128_ctr_state;
+
 	fastd_crypto_ghash_state_t *cstate_ghash;
 };
 
@@ -68,14 +71,15 @@ static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, c
 
 	fastd_method_common_init(ctx, &session->common, initiator);
 
-	fastd_block128_t key;
-	memcpy(key.b, secret, sizeof(fastd_block128_t));
-	session->cstate_aes128ctr = ctx->conf->crypto_aes128ctr->set_key(ctx, ctx->crypto_aes128ctr, &key);
+	if (!fastd_cipher_get_by_name(ctx, "aes128-ctr", &session->aes128_ctr, &session->aes128_ctr_ctx))
+		exit_bug(ctx, "aes128-gcm: can't instanciate aes128-ctr");
+
+	session->aes128_ctr_state = session->aes128_ctr->init_state(ctx, session->aes128_ctr_ctx, secret);
 
 	static const fastd_block128_t zeroblock = {};
 	fastd_block128_t H;
 
-	ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, &H, &zeroblock, sizeof(fastd_block128_t), &zeroblock);
+	session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, &H, &zeroblock, sizeof(fastd_block128_t), &zeroblock);
 
 	session->cstate_ghash = ctx->conf->crypto_ghash->set_h(ctx, ctx->crypto_ghash, &H);
 
@@ -107,7 +111,7 @@ static void method_session_superseded(fastd_context_t *ctx, fastd_method_session
 
 static void method_session_free(fastd_context_t *ctx, fastd_method_session_state_t *session) {
 	if (session) {
-		ctx->conf->crypto_aes128ctr->free_state(ctx, session->cstate_aes128ctr);
+		session->aes128_ctr->free_state(ctx, session->aes128_ctr_state);
 		ctx->conf->crypto_ghash->free_state(ctx, session->cstate_ghash);
 
 		secure_memzero(session, sizeof(fastd_method_session_state_t));
@@ -145,7 +149,7 @@ static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fast
 	fastd_block128_t *outblocks = out->data;
 	fastd_block128_t sig;
 
-	bool ok = ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
+	bool ok = session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
 
 	if (ok) {
 		if (tail_len)
@@ -201,7 +205,7 @@ static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_metho
 	fastd_block128_t *outblocks = out->data;
 	fastd_block128_t sig;
 
-	bool ok = ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
+	bool ok = session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
 
 	if (ok) {
 		if (tail_len)
diff --git a/src/methods/methods.c.in b/src/methods/methods.c.in
index 6931edd..8f5bb10 100644
--- a/src/methods/methods.c.in
+++ b/src/methods/methods.c.in
@@ -30,13 +30,12 @@
 @METHOD_DEFINITIONS@
 
 static const fastd_method_t *const methods[] = { @METHOD_LIST@
-	NULL
 };
 
 
 const fastd_method_t* fastd_method_get_by_name(const char *name) {
-	int i;
-	for (i = 0; methods[i]; i++) {
+	size_t i;
+	for (i = 0; i < array_size(methods); i++) {
 		if (!strcmp(methods[i]->name, name))
 			return methods[i];
 	}
diff --git a/src/types.h b/src/types.h
index a2b7d38..894b2af 100644
--- a/src/types.h
+++ b/src/types.h
@@ -36,6 +36,7 @@
 #include <fastd_config.h>
 
 #include <stdbool.h>
+#include <stdint.h>
 
 
 #define UNUSED __attribute__((unused))
@@ -113,6 +114,7 @@ typedef struct fastd_context fastd_context_t;
 
 typedef struct fastd_protocol fastd_protocol_t;
 typedef struct fastd_method fastd_method_t;
+typedef struct fastd_cipher fastd_cipher_t;
 
 typedef struct fastd_handshake fastd_handshake_t;
 
@@ -121,14 +123,17 @@ typedef struct fastd_string_stack fastd_string_stack_t;
 
 typedef struct fastd_resolve_return fastd_resolve_return_t;
 
-#ifdef USE_CRYPTO_AES128CTR
-typedef struct fastd_crypto_aes128ctr fastd_crypto_aes128ctr_t;
-#endif
 #ifdef USE_CRYPTO_GHASH
 typedef struct fastd_crypto_ghash fastd_crypto_ghash_t;
 #endif
 
 
+typedef union fastd_block128 {
+	uint8_t b[16];
+	uint64_t qw[2];
+} __attribute__((aligned(16))) fastd_block128_t;
+
+
 /* May be defined by the protocol/method/crypto implementations however they like */
 typedef struct fastd_protocol_config fastd_protocol_config_t;
 typedef struct fastd_protocol_state fastd_protocol_state_t;
@@ -137,10 +142,8 @@ typedef struct fastd_protocol_peer_state fastd_protocol_peer_state_t;
 
 typedef struct fastd_method_session_state fastd_method_session_state_t;
 
-#ifdef USE_CRYPTO_AES128CTR
-typedef struct fastd_crypto_aes128ctr_context fastd_crypto_aes128ctr_context_t;
-typedef struct fastd_crypto_aes128ctr_state fastd_crypto_aes128ctr_state_t;
-#endif
+typedef struct fastd_cipher_context fastd_cipher_context_t;
+typedef struct fastd_cipher_state fastd_cipher_state_t;
 
 #ifdef USE_CRYPTO_GHASH
 typedef struct fastd_crypto_ghash_context fastd_crypto_ghash_context_t;