Separate handshake from encryption method

1 files changed, 749 insertions, 0 deletions

diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c
new file mode 100644
index 0000000..3168d03
--- /dev/null
+++ b/src/protocol_ec25519_fhmqvc.c
@@ -0,0 +1,749 @@
+/*
+  Copyright (c) 2012, 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.
+*/
+
+
+#define _GNU_SOURCE
+
+#include "fastd.h"
+#include "handshake.h"
+#include "peer.h"
+#include "task.h"
+
+#include <arpa/inet.h>
+
+#include <libuecc/ecc.h>
+#include <crypto_auth_hmacsha256.h>
+#include <crypto_hash_sha256.h>
+
+
+#define PUBLICKEYBYTES 32
+#define SECRETKEYBYTES 32
+#define HMACBYTES crypto_auth_hmacsha256_BYTES
+#define HASHBYTES crypto_hash_sha256_BYTES
+
+
+#if HASHBYTES != crypto_auth_hmacsha256_KEYBYTES
+#error bug: HASHBYTES != crypto_auth_hmacsha256_KEYBYTES
+#endif
+
+#if HASHBYTES != SECRETKEYBYTES
+#error bug: HASHBYTES != SECRETKEYBYTES
+#endif
+
+
+struct _fastd_protocol_config {
+	ecc_secret_key_256 secret_key;
+	ecc_public_key_256 public_key;
+};
+
+typedef enum _handshake_state {
+	HANDSHAKE_STATE_INIT,
+	HANDSHAKE_STATE_RESPONSE,
+	HANDSHAKE_STATE_ESTABLISHED
+} handshake_state;
+
+struct _fastd_protocol_peer_config {
+	ecc_public_key_256 public_key;
+};
+
+typedef struct _protocol_handshake {
+	const fastd_peer_config *peer_config;
+
+	handshake_state state;
+	ecc_secret_key_256 secret_key;
+	ecc_public_key_256 public_key;
+	ecc_public_key_256 peer_key;
+	ecc_public_key_256 sigma;
+	uint8_t shared_handshake_key[HASHBYTES];
+} protocol_handshake;
+
+typedef struct _protocol_session {
+	bool handshakes_cleaned;
+	bool refreshing;
+
+	fastd_method_session_state *method_state;
+} protocol_session;
+
+struct _fastd_protocol_peer_state {
+	protocol_session old_session;
+	protocol_session session;
+
+	protocol_handshake *initiating_handshake;
+	protocol_handshake *accepting_handshake;
+};
+
+
+#define RECORD_SENDER_KEY RECORD_PROTOCOL1
+#define RECORD_RECEIPIENT_KEY RECORD_PROTOCOL2
+#define RECORD_SENDER_HANDSHAKE_KEY RECORD_PROTOCOL3
+#define RECORD_RECEIPIENT_HANDSHAKE_KEY RECORD_PROTOCOL4
+#define RECORD_T RECORD_PROTOCOL5
+
+
+static void protocol_send(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer);
+
+
+static inline bool read_key(uint8_t key[32], const char *hexkey) {
+	if ((strlen(hexkey) != 64) || (strspn(hexkey, "0123456789abcdefABCDEF") != 64))
+		return false;
+
+	int i;
+	for (i = 0; i < 32; i++)
+		sscanf(&hexkey[2*i], "%02hhx", &key[i]);
+
+	return true;
+}
+
+static inline bool is_session_valid(fastd_context *ctx, const protocol_session *session) {
+	return ctx->conf->method->session_is_valid(ctx, session->method_state);
+}
+
+static inline void check_session_refresh(fastd_context *ctx, fastd_peer *peer) {
+	protocol_session *session = &peer->protocol_state->session;
+
+	if (!session->refreshing && ctx->conf->method->session_want_refresh(ctx, session->method_state)) {
+		pr_debug(ctx, "refreshing session with %P", peer);
+		session->refreshing = true;
+		fastd_task_schedule_handshake(ctx, peer, 0);
+	}
+}
+
+static fastd_protocol_config* protocol_init(fastd_context *ctx) {
+	fastd_protocol_config *protocol_config = malloc(sizeof(fastd_protocol_config));
+
+	if (!ctx->conf->secret)
+		exit_error(ctx, "no secret key configured");
+
+	if (!read_key(protocol_config->secret_key.s, ctx->conf->secret))
+		exit_error(ctx, "invalid secret key");
+
+	ecc_25519_work work;
+	ecc_25519_scalarmult_base(&work, &protocol_config->secret_key);
+	ecc_25519_store(&protocol_config->public_key, &work);
+
+	return protocol_config;
+}
+
+static void protocol_peer_configure(fastd_context *ctx, fastd_peer_config *peer_conf) {
+	ecc_public_key_256 key;
+
+	if (!peer_conf->key) {
+		pr_warn(ctx, "no key configured for `%s', disabling peer", peer_conf->name);
+		peer_conf->enabled = false;
+		return;
+	}
+
+	if (!read_key(key.p, peer_conf->key)) {
+		pr_warn(ctx, "invalid key configured for `%s', disabling peer", peer_conf->name);
+		peer_conf->enabled = false;
+		return;
+	}
+
+	peer_conf->protocol_config = malloc(sizeof(fastd_protocol_peer_config));
+	peer_conf->protocol_config->public_key = key;
+}
+
+static void init_peer_state(fastd_context *ctx, fastd_peer *peer) {
+	if (peer->protocol_state)
+		return;
+
+	peer->protocol_state = malloc(sizeof(fastd_protocol_peer_state));
+	memset(peer->protocol_state, 0, sizeof(fastd_protocol_peer_state));
+}
+
+static inline void free_handshake(protocol_handshake *handshake) {
+	if (handshake) {
+		memset(handshake, 0, sizeof(protocol_handshake));
+		free(handshake);
+	}
+}
+
+static void protocol_peer_config_purged(fastd_context *ctx, fastd_peer_config *peer_conf) {
+	fastd_peer *peer;
+	for (peer = ctx->peers; peer; peer = peer->next) {
+		if (!peer->protocol_state)
+			continue;
+
+		if (peer->protocol_state->initiating_handshake &&
+		    peer->protocol_state->initiating_handshake->peer_config == peer_conf) {
+			free_handshake(peer->protocol_state->initiating_handshake);
+			peer->protocol_state->initiating_handshake = NULL;
+		}
+
+		if (peer->protocol_state->accepting_handshake &&
+		    peer->protocol_state->accepting_handshake->peer_config == peer_conf) {
+			free_handshake(peer->protocol_state->accepting_handshake);
+			peer->protocol_state->accepting_handshake = NULL;
+		}
+	}
+}
+
+static protocol_handshake* new_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_peer_config *peer_config, bool initiate) {
+	protocol_handshake **handshake;
+
+	if (initiate)
+		handshake = &peer->protocol_state->initiating_handshake;
+	else
+		handshake = &peer->protocol_state->accepting_handshake;
+
+	free_handshake(*handshake);
+
+	*handshake = malloc(sizeof(protocol_handshake));
+
+	(*handshake)->peer_config = peer_config;
+
+	(*handshake)->state = HANDSHAKE_STATE_INIT;
+
+	fastd_random_bytes(ctx, (*handshake)->secret_key.s, 32, false);
+	ecc_25519_secret_sanitize(&(*handshake)->secret_key, &(*handshake)->secret_key);
+
+	ecc_25519_work work;
+	ecc_25519_scalarmult_base(&work, &(*handshake)->secret_key);
+	ecc_25519_store(&(*handshake)->public_key, &work);
+
+	return *handshake;
+}
+
+static void protocol_handshake_init(fastd_context *ctx, fastd_peer *peer) {
+	init_peer_state(ctx, peer);
+
+	fastd_buffer buffer = fastd_handshake_new_init(ctx, peer, 3*(4+PUBLICKEYBYTES) /* sender key, receipient key, handshake key */);
+
+	protocol_handshake *handshake = new_handshake(ctx, peer, peer->config, true);
+
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p);
+
+	if (handshake->peer_config)
+		fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, handshake->peer_config->protocol_config->public_key.p);
+	else
+		pr_debug(ctx, "sending handshake to unknown peer %P", peer);
+
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, handshake->public_key.p);
+
+	fastd_task_put_send_handshake(ctx, peer, buffer);
+}
+
+static inline bool has_field(const fastd_handshake *handshake, uint8_t type, size_t length) {
+	return (handshake->records[type].length == length);
+}
+
+static void respond_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
+	pr_debug(ctx, "responding handshake with %P...", peer);
+
+	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hashbuf[HASHBYTES];
+	uint8_t hmacbuf[HMACBYTES];
+
+	memcpy(hashinput, peer->protocol_state->accepting_handshake->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+2*PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+3*PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key.p, PUBLICKEYBYTES);
+
+	crypto_hash_sha256(hashbuf, hashinput, 4*PUBLICKEYBYTES);
+
+	ecc_secret_key_256 d = {{0}}, e = {{0}}, eb, s;
+
+	memcpy(d.s, hashbuf, HASHBYTES/2);
+	memcpy(e.s, hashbuf+HASHBYTES/2, HASHBYTES/2);
+
+	d.s[15] |= 0x80;
+	e.s[15] |= 0x80;
+
+	ecc_25519_secret_mult(&eb, &e, &ctx->conf->protocol_config->secret_key);
+	ecc_25519_secret_add(&s, &eb, &peer->protocol_state->accepting_handshake->secret_key);
+
+	ecc_25519_work work, workX;
+	ecc_25519_load(&work, &peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key);
+	ecc_25519_load(&workX, &peer->protocol_state->accepting_handshake->peer_key);
+
+	ecc_25519_scalarmult(&work, &d, &work);
+	ecc_25519_add(&work, &workX, &work);
+	ecc_25519_scalarmult(&work, &s, &work);
+
+	if (ecc_25519_is_identity(&work))
+		return;
+
+	ecc_25519_store(&peer->protocol_state->accepting_handshake->sigma, &work);
+
+	memcpy(hashinput+4*PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->sigma.p, PUBLICKEYBYTES);
+	crypto_hash_sha256(peer->protocol_state->accepting_handshake->shared_handshake_key, hashinput, 5*PUBLICKEYBYTES);
+
+	memcpy(hashinput, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->public_key.p, PUBLICKEYBYTES);
+
+	crypto_auth_hmacsha256(hmacbuf, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->shared_handshake_key);
+
+	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(4+PUBLICKEYBYTES) + 4+HMACBYTES);
+
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_T, HMACBYTES, hmacbuf);
+
+	fastd_task_put_send_handshake(ctx, peer, buffer);
+
+	peer->protocol_state->accepting_handshake->state = HANDSHAKE_STATE_RESPONSE;
+}
+
+static void establish(fastd_context *ctx, fastd_peer *peer, const fastd_peer_config *peer_config, bool initiator,
+		      const ecc_public_key_256 *A, const ecc_public_key_256 *B, const ecc_public_key_256 *X,
+		      const ecc_public_key_256 *Y, const ecc_public_key_256 *sigma) {
+	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hash[HASHBYTES];
+
+	pr_verbose(ctx, "New session with %P established.", peer);
+
+	if (is_session_valid(ctx, &peer->protocol_state->session) && !is_session_valid(ctx, &peer->protocol_state->old_session)) {
+		ctx->conf->method->session_free(ctx, peer->protocol_state->old_session.method_state);
+		peer->protocol_state->old_session = peer->protocol_state->session;
+	}
+	else {
+		ctx->conf->method->session_free(ctx, peer->protocol_state->session.method_state);
+	}
+
+	memcpy(hashinput, X->p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, Y->p, PUBLICKEYBYTES);
+	memcpy(hashinput+2*PUBLICKEYBYTES, A->p, PUBLICKEYBYTES);
+	memcpy(hashinput+3*PUBLICKEYBYTES, B->p, PUBLICKEYBYTES);
+	memcpy(hashinput+4*PUBLICKEYBYTES, sigma->p, PUBLICKEYBYTES);
+	crypto_hash_sha256(hash, hashinput, 5*PUBLICKEYBYTES);
+
+	peer->protocol_state->session.handshakes_cleaned = false;
+	peer->protocol_state->session.refreshing = false;
+	peer->protocol_state->session.method_state = ctx->conf->method->session_init(ctx, hash, HASHBYTES, initiator);
+
+	free_handshake(peer->protocol_state->initiating_handshake);
+	peer->protocol_state->initiating_handshake = NULL;
+
+	free_handshake(peer->protocol_state->accepting_handshake);
+	peer->protocol_state->accepting_handshake = NULL;
+
+	fastd_peer_seen(ctx, peer);
+
+	if (peer_config != peer->config) {
+		fastd_peer *perm_peer;
+		for (perm_peer = ctx->peers; perm_peer; perm_peer = perm_peer->next) {
+			if (perm_peer->config == peer_config) {
+				peer = fastd_peer_set_established_merge(ctx, perm_peer, peer);
+				break;
+			}
+		}
+	}
+	else {
+		fastd_peer_set_established(ctx, peer);
+	}
+
+	fastd_task_schedule_keepalive(ctx, peer, ctx->conf->keepalive_interval*1000);
+
+	if (!initiator)
+		protocol_send(ctx, peer, fastd_buffer_alloc(0, ctx->conf->method->min_encrypt_head_space(ctx), 0));
+}
+
+static void finish_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
+	pr_debug(ctx, "finishing handshake with %P...", peer);
+
+	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hashbuf[HASHBYTES];
+	uint8_t hmacbuf[HMACBYTES];
+
+	memcpy(hashinput, peer->protocol_state->initiating_handshake->peer_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+2*PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+3*PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
+
+	crypto_hash_sha256(hashbuf, hashinput, 4*PUBLICKEYBYTES);
+
+	ecc_secret_key_256 d = {{0}}, e = {{0}}, da, s;
+
+	memcpy(d.s, hashbuf, HASHBYTES/2);
+	memcpy(e.s, hashbuf+HASHBYTES/2, HASHBYTES/2);
+
+	d.s[15] |= 0x80;
+	e.s[15] |= 0x80;
+
+	ecc_25519_secret_mult(&da, &d, &ctx->conf->protocol_config->secret_key);
+	ecc_25519_secret_add(&s, &da, &peer->protocol_state->initiating_handshake->secret_key);
+
+	ecc_25519_work work, workY;
+	ecc_25519_load(&work, &peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key);
+	ecc_25519_load(&workY, &peer->protocol_state->initiating_handshake->peer_key);
+
+	ecc_25519_scalarmult(&work, &e, &work);
+	ecc_25519_add(&work, &workY, &work);
+	ecc_25519_scalarmult(&work, &s, &work);
+
+	if (ecc_25519_is_identity(&work))
+		return;
+
+	ecc_25519_store(&peer->protocol_state->initiating_handshake->sigma, &work);
+
+	memcpy(hashinput+4*PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->sigma.p, PUBLICKEYBYTES);
+	crypto_hash_sha256(peer->protocol_state->initiating_handshake->shared_handshake_key, hashinput, 5*PUBLICKEYBYTES);
+
+	memcpy(hashinput, peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->peer_key.p, PUBLICKEYBYTES);
+
+	if(crypto_auth_hmacsha256_verify(handshake->records[RECORD_T].data, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->shared_handshake_key) != 0) {
+		pr_warn(ctx, "received invalid protocol handshake response from %P", peer);
+		return;
+	}
+
+	memcpy(hashinput, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->public_key.p, PUBLICKEYBYTES);
+	crypto_auth_hmacsha256(hmacbuf, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->shared_handshake_key);
+
+	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(4+PUBLICKEYBYTES) + 4+HMACBYTES);
+
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->public_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->peer_key.p);
+	fastd_handshake_add(ctx, &buffer, RECORD_T, HMACBYTES, hmacbuf);
+
+	fastd_task_put_send_handshake(ctx, peer, buffer);
+
+	establish(ctx, peer, peer->protocol_state->initiating_handshake->peer_config, true,
+		  &peer->protocol_state->initiating_handshake->public_key,
+		  &peer->protocol_state->initiating_handshake->peer_key,
+		  &ctx->conf->protocol_config->public_key,
+		  &peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key,
+		  &peer->protocol_state->initiating_handshake->sigma);
+}
+
+static void handle_finish_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
+	pr_debug(ctx, "handling handshake finish with %P...", peer);
+
+	uint8_t hashinput[2*PUBLICKEYBYTES];
+
+	memcpy(hashinput, peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key.p, PUBLICKEYBYTES);
+	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_key.p, PUBLICKEYBYTES);
+
+	if(crypto_auth_hmacsha256_verify(handshake->records[RECORD_T].data, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->shared_handshake_key) != 0) {
+		pr_warn(ctx, "received invalid protocol handshake finish from %P", peer);
+		return;
+	}
+
+	establish(ctx, peer, peer->protocol_state->accepting_handshake->peer_config, false,
+		  &peer->protocol_state->accepting_handshake->peer_key,
+		  &peer->protocol_state->accepting_handshake->public_key,
+		  &peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key,
+		  &ctx->conf->protocol_config->public_key,
+		  &peer->protocol_state->accepting_handshake->sigma);
+}
+
+static inline const fastd_peer_config* match_sender_key(fastd_context *ctx, const fastd_peer *peer, const unsigned char key[32]) {
+	if (peer->config) {
+		if (memcmp(peer->config->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0)
+			return peer->config;
+	}
+
+	if (fastd_peer_is_temporary(peer) || fastd_peer_is_floating(peer)) {
+		fastd_peer_config *config;
+		for (config = ctx->conf->peers; config; config = config->next) {
+			if (!fastd_peer_config_is_floating(config))
+				continue;
+
+		if (memcmp(config->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0)
+			return config;
+		}
+	}
+
+	return NULL;
+}
+
+static void kill_handshakes(fastd_context *ctx, fastd_peer *peer) {
+	pr_debug(ctx, "there is a handshake conflict, retrying in a moment...");
+
+	free_handshake(peer->protocol_state->initiating_handshake);
+	peer->protocol_state->initiating_handshake = NULL;
+
+	free_handshake(peer->protocol_state->accepting_handshake);
+	peer->protocol_state->accepting_handshake = NULL;
+}
+
+static void protocol_handshake_handle(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake) {
+	init_peer_state(ctx, peer);
+
+	if (!has_field(handshake, RECORD_SENDER_KEY, PUBLICKEYBYTES)) {
+		pr_debug(ctx, "received handshake without sender key from %P", peer);
+		return;
+	}
+
+	const fastd_peer_config *peer_config = match_sender_key(ctx, peer, handshake->records[RECORD_SENDER_KEY].data);
+
+	if (handshake->type > 1 && !has_field(handshake, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES)) {
+		pr_debug(ctx, "received handshake reply without receipient key from %P", peer);
+		return;
+	}
+	else if(has_field(handshake, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES)) {
+		if (memcmp(ctx->conf->protocol_config->public_key.p, handshake->records[RECORD_RECEIPIENT_KEY].data, PUBLICKEYBYTES) != 0) {
+			pr_debug(ctx, "received protocol handshake with wrong receipient key from %P", peer);
+			return;
+		}
+	}
+
+	if (!has_field(handshake, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES)) {
+		pr_debug(ctx, "received handshake without sender handshake key from %P", peer);
+		return;
+	}
+
+	if (handshake->type > 1 && !has_field(handshake, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES)) {
+		pr_debug(ctx, "received handshake reply without receipient handshake key from %P", peer);
+		return;
+	}
+
+	if (handshake->type > 1 && !has_field(handshake, RECORD_T, HMACBYTES)) {
+		pr_debug(ctx, "received handshake reply without HMAC from %P", peer);
+		return;
+	}
+
+	switch(handshake->type) {
+	case 1:
+		new_handshake(ctx, peer, peer_config, false);
+		memcpy(peer->protocol_state->accepting_handshake->peer_key.p, handshake->records[RECORD_SENDER_HANDSHAKE_KEY].data, PUBLICKEYBYTES);
+		respond_handshake(ctx, peer, handshake);
+		break;
+
+	case 2:
+		if (!peer->protocol_state->initiating_handshake || peer->protocol_state->initiating_handshake->state != HANDSHAKE_STATE_INIT) {
+			pr_debug(ctx, "received unexpected handshake response from %P", peer);
+			return;
+		}
+
+		if (peer->protocol_state->initiating_handshake->peer_config != peer_config) {
+			if (peer->protocol_state->initiating_handshake->peer_config) {
+				pr_debug(ctx, "received handshake response with wrong sender key from %P", peer);
+				return;
+			}
+			else {
+				peer->protocol_state->initiating_handshake->peer_config = peer_config;
+			}
+		}
+
+		if (memcmp(peer->protocol_state->initiating_handshake->public_key.p, handshake->records[RECORD_RECEIPIENT_HANDSHAKE_KEY].data, PUBLICKEYBYTES) != 0) {
+			pr_debug(ctx, "received handshake response with unexpected receipient handshake key from %P", peer);
+			return;
+		}
+
+		pr_debug(ctx, "received handshake response from %P", peer);
+
+		if (peer->protocol_state->accepting_handshake) {
+			kill_handshakes(ctx, peer);
+			return;
+		}
+
+		memcpy(peer->protocol_state->initiating_handshake->peer_key.p, handshake->records[RECORD_SENDER_HANDSHAKE_KEY].data, PUBLICKEYBYTES);
+
+		finish_handshake(ctx, peer, handshake);
+		break;
+
+	case 3:
+		if (!peer->protocol_state->accepting_handshake || peer->protocol_state->accepting_handshake->state != HANDSHAKE_STATE_RESPONSE) {
+			pr_debug(ctx, "received unexpected protocol handshake finish from %P", peer);
+			return;
+		}
+
+		if (peer->protocol_state->accepting_handshake->peer_config != peer_config) {
+			pr_debug(ctx, "received protocol handshake finish with wrong sender key from %P", peer);
+			return;
+		}
+
+		if (memcmp(peer->protocol_state->accepting_handshake->public_key.p, handshake->records[RECORD_RECEIPIENT_HANDSHAKE_KEY].data, PUBLICKEYBYTES) != 0) {
+			pr_debug(ctx, "received handshake response with unexpected receipient handshake key from %P", peer);
+			return;
+		}
+
+		if (memcmp(peer->protocol_state->accepting_handshake->peer_key.p, handshake->records[RECORD_SENDER_HANDSHAKE_KEY].data, PUBLICKEYBYTES) != 0) {
+			pr_debug(ctx, "received handshake response with unexpected sender handshake key from %P", peer);
+			return;
+		}
+
+		pr_debug(ctx, "received handshake finish from %P", peer);
+
+		if (peer->protocol_state->initiating_handshake && peer->protocol_state->initiating_handshake->state != HANDSHAKE_STATE_INIT) {
+			kill_handshakes(ctx, peer);
+			return;
+		}
+
+		handle_finish_handshake(ctx, peer, handshake);
+		break;
+
+	default:
+		pr_debug(ctx, "received handshake reply with unknown type %u", handshake->type);
+	}
+}
+
+static void protocol_handle_recv(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer) {
+	if (!fastd_peer_is_established(peer)) {
+		pr_debug(ctx, "received unexpected packet from %P", peer);
+
+		if (fastd_peer_is_temporary(peer)) {
+			pr_debug(ctx, "sending handshake to temporary peer %P", peer);
+			fastd_task_schedule_handshake(ctx, peer, 0);
+		}
+
+		goto fail;
+	}
+
+	if (!peer->protocol_state || !is_session_valid(ctx, &peer->protocol_state->session))
+		goto fail;
+
+	fastd_buffer recv_buffer;
+	bool ok = false;
+
+	if (is_session_valid(ctx, &peer->protocol_state->old_session)) {
+		if (ctx->conf->method->decrypt(ctx, peer->protocol_state->old_session.method_state, &recv_buffer, buffer))
+			ok = true;
+	}
+
+	if (!ok) {
+		if (ctx->conf->method->decrypt(ctx, peer->protocol_state->session.method_state, &recv_buffer, buffer)) {
+			ok = true;
+
+			if (!peer->protocol_state->session.handshakes_cleaned) {
+				pr_debug(ctx, "cleaning left handshakes with %P", peer);
+				fastd_task_delete_peer_handshakes(ctx, peer);
+				peer->protocol_state->session.handshakes_cleaned = true;
+
+				if (ctx->conf->method->session_is_initiator(ctx, peer->protocol_state->session.method_state))
+					protocol_send(ctx, peer, fastd_buffer_alloc(0, ctx->conf->method->min_encrypt_head_space(ctx), 0));
+			}
+
+			if (peer->protocol_state->old_session.method_state) {
+				pr_debug(ctx, "invalidating old session with %P", peer);
+				ctx->conf->method->session_free(ctx, peer->protocol_state->old_session.method_state);
+				peer->protocol_state->old_session.method_state = NULL;
+			}
+
+			check_session_refresh(ctx, peer);
+		}
+	}
+
+	if (!ok) {
+		pr_debug(ctx, "verification failed for packet received from %P", peer);
+		goto fail;
+	}
+
+	fastd_peer_seen(ctx, peer);
+
+	if (recv_buffer.len)
+		fastd_task_put_handle_recv(ctx, peer, recv_buffer);
+	else
+		fastd_buffer_free(recv_buffer);
+
+	return;
+
+ fail:
+	fastd_buffer_free(buffer);
+}
+
+static void protocol_send(fastd_context *ctx, fastd_peer *peer, fastd_buffer buffer) {
+	if (!peer->protocol_state || !is_session_valid(ctx, &peer->protocol_state->session))
+		goto fail;
+
+	check_session_refresh(ctx, peer);
+
+	protocol_session *session;
+	if (ctx->conf->method->session_is_initiator(ctx, peer->protocol_state->session.method_state) && is_session_valid(ctx, &peer->protocol_state->old_session)) {
+		pr_debug(ctx, "sending packet for old session to %P", peer);
+		session = &peer->protocol_state->old_session;
+	}
+	else {
+		session = &peer->protocol_state->session;
+	}
+
+	fastd_buffer send_buffer;
+	if (!ctx->conf->method->encrypt(ctx, session->method_state, &send_buffer, buffer))
+		goto fail;
+	
+	fastd_task_put_send(ctx, peer, send_buffer);
+
+	fastd_task_delete_peer_keepalives(ctx, peer);
+	fastd_task_schedule_keepalive(ctx, peer, ctx->conf->keepalive_interval*1000);
+	return;
+
+ fail:
+	fastd_buffer_free(buffer);
+}
+
+static void protocol_free_peer_state(fastd_context *ctx, fastd_peer *peer) {
+	if (peer->protocol_state) {
+		free_handshake(peer->protocol_state->initiating_handshake);
+		free_handshake(peer->protocol_state->accepting_handshake);
+
+		ctx->conf->method->session_free(ctx, peer->protocol_state->old_session.method_state);
+		ctx->conf->method->session_free(ctx, peer->protocol_state->session.method_state);
+
+		free(peer->protocol_state);
+	}
+}
+
+
+static void hexdump(const char *desc, unsigned char d[32]) {
+	printf("%s", desc);
+
+	int i;
+	for (i = 0; i < 32; i++)
+		printf("%02x", d[i]);
+
+	printf("\n");
+}
+
+static void protocol_generate_key(fastd_context *ctx) {
+	ecc_secret_key_256 secret_key;
+	ecc_public_key_256 public_key;
+
+	pr_info(ctx, "Reading 32 bytes from /dev/random...");
+
+	fastd_random_bytes(ctx, secret_key.s, 32, true);
+	ecc_25519_secret_sanitize(&secret_key, &secret_key);
+
+	ecc_25519_work work;
+	ecc_25519_scalarmult_base(&work, &secret_key);
+	ecc_25519_store(&public_key, &work);
+
+	hexdump("Secret: ", secret_key.s);
+	hexdump("Public: ", public_key.p);
+}
+
+
+const fastd_protocol fastd_protocol_ec25519_fhmqvc = {
+	.name = "ec25519-fhmqvc",
+
+	.init = protocol_init,
+	.peer_configure = protocol_peer_configure,
+	.peer_config_purged = protocol_peer_config_purged,
+
+	.handshake_init = protocol_handshake_init,
+	.handshake_handle = protocol_handshake_handle,
+
+	.handle_recv = protocol_handle_recv,
+	.send = protocol_send,
+
+	.free_peer_state = protocol_free_peer_state,
+
+	.generate_key = protocol_generate_key,
+};