Add support for defining the MTU per peer

1 files changed, 25 insertions, 21 deletions

diff --git a/src/handshake.c b/src/handshake.c
index 726c117..000d685 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -176,7 +176,7 @@ static fastd_string_stack_t * parse_string_list(const uint8_t *data, size_t len)
 }
 
 /** Allocates and initializes a new handshake packet */
-static fastd_handshake_buffer_t new_handshake(uint8_t type, bool little_endian, const fastd_method_info_t *method, const fastd_string_stack_t *methods, size_t tail_space) {
+static fastd_handshake_buffer_t new_handshake(uint8_t type, bool little_endian, uint16_t mtu, const fastd_method_info_t *method, const fastd_string_stack_t *methods, size_t tail_space) {
 	size_t version_len = strlen(FASTD_VERSION);
 	size_t protocol_len = strlen(conf.protocol->name);
 	size_t method_len = method ? strlen(method->name) : 0;
@@ -190,7 +190,7 @@ static fastd_handshake_buffer_t new_handshake(uint8_t type, bool little_endian,
 	fastd_handshake_buffer_t buffer = {
 		.buffer = fastd_buffer_alloc(sizeof(fastd_handshake_packet_t), 1,
 					     3*5 +               /* handshake type, mode, reply code */
-					     6 +                 /* MTU */
+					     (mtu ? 6 : 0) +     /* MTU */
 					     4+version_len +     /* version name */
 					     4+protocol_len +    /* protocol name */
 					     4+method_len +      /* method name */
@@ -204,7 +204,9 @@ static fastd_handshake_buffer_t new_handshake(uint8_t type, bool little_endian,
 
 	fastd_handshake_add_uint8(&buffer, RECORD_HANDSHAKE_TYPE, type);
 	fastd_handshake_add_uint8(&buffer, RECORD_MODE, get_mode_id());
-	fastd_handshake_add_uint16_endian(&buffer, RECORD_MTU, conf.mtu);
+
+	if (mtu)
+		fastd_handshake_add_uint16_endian(&buffer, RECORD_MTU, mtu);
 
 	fastd_handshake_add(&buffer, RECORD_VERSION_NAME, version_len, FASTD_VERSION);
 	fastd_handshake_add(&buffer, RECORD_PROTOCOL_NAME, protocol_len, conf.protocol->name);
@@ -222,18 +224,18 @@ static fastd_handshake_buffer_t new_handshake(uint8_t type, bool little_endian,
 
 /** Allocates and initializes a new initial handshake packet */
 fastd_handshake_buffer_t fastd_handshake_new_init(size_t tail_space) {
-	return new_handshake(1, true, NULL, conf.secure_handshakes ? NULL : conf.peer_group->methods, tail_space);
+	return new_handshake(1, true, 0, NULL, conf.secure_handshakes ? NULL : conf.peer_group->methods, tail_space);
 }
 
 /** Allocates and initializes a new reply handshake packet */
-fastd_handshake_buffer_t fastd_handshake_new_reply(uint8_t type, bool little_endian, const fastd_method_info_t *method, const fastd_string_stack_t *methods, size_t tail_space) {
-	fastd_handshake_buffer_t buffer = new_handshake(type, little_endian, method, methods, tail_space);
+fastd_handshake_buffer_t fastd_handshake_new_reply(uint8_t type, bool little_endian, uint16_t mtu, const fastd_method_info_t *method, const fastd_string_stack_t *methods, size_t tail_space) {
+	fastd_handshake_buffer_t buffer = new_handshake(type, little_endian, mtu, method, methods, tail_space);
 	fastd_handshake_add_uint8(&buffer, RECORD_REPLY_CODE, 0);
 	return buffer;
 }
 
 /** Prints the error corresponding to the given reply code and error detail */
-static void print_error(const char *prefix, const fastd_peer_address_t *remote_addr, uint8_t reply_code, uint16_t error_detail) {
+static void print_error(const char *prefix, const fastd_peer_t *peer, const fastd_peer_address_t *remote_addr, uint8_t reply_code, uint16_t error_detail) {
 	const char *error_field_str;
 
 	if (error_detail >= RECORD_MAX)
@@ -260,7 +262,7 @@ static void print_error(const char *prefix, const fastd_peer_address_t *remote_a
 			break;
 
 		case RECORD_MTU:
-			pr_warn("Handshake with %I failed: %s error: MTU configuration differs with peer (local MTU is %u)", remote_addr, prefix, conf.mtu);
+			pr_warn("Handshake with %I failed: %s error: MTU configuration differs with peer (local MTU is %u)", remote_addr, prefix, fastd_peer_get_mtu(peer));
 			break;
 
 		case RECORD_METHOD_NAME:
@@ -281,7 +283,7 @@ static void print_error(const char *prefix, const fastd_peer_address_t *remote_a
 
 /** Sends an error reply to a peer */
 void fastd_handshake_send_error(fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const fastd_handshake_t *handshake, uint8_t reply_code, uint16_t error_detail) {
-	print_error("sending", remote_addr, reply_code, error_detail);
+	print_error("sending", peer, remote_addr, reply_code, error_detail);
 
 	fastd_handshake_buffer_t buffer = {
 		.buffer = fastd_buffer_alloc(sizeof(fastd_handshake_packet_t), 0, 3*5 /* enough space for handshake type, reply code and error detail */),
@@ -355,14 +357,14 @@ static inline fastd_handshake_t parse_tlvs(const fastd_buffer_t *buffer) {
 }
 
 /** Prints the error found in a received handshake */
-static inline void print_error_reply(const fastd_peer_address_t *remote_addr, const fastd_handshake_t *handshake) {
+static inline void print_error_reply(const fastd_peer_t *peer, const fastd_peer_address_t *remote_addr, const fastd_handshake_t *handshake) {
 	uint8_t reply_code = as_uint8(&handshake->records[RECORD_REPLY_CODE]);
 	uint16_t error_detail = RECORD_MAX;
 
 	if (handshake->records[RECORD_ERROR_DETAIL].length == 1 || handshake->records[RECORD_ERROR_DETAIL].length == 2)
 		error_detail = as_uint(&handshake->records[RECORD_ERROR_DETAIL]);
 
-	print_error("received", remote_addr, reply_code, error_detail);
+	print_error("received", peer, remote_addr, reply_code, error_detail);
 }
 
 /** Does some basic validity checks on a received handshake */
@@ -381,15 +383,6 @@ static inline bool check_records(fastd_socket_t *sock, const fastd_peer_address_
 		}
 	}
 
-	if (!conf.secure_handshakes || handshake->type > 1) {
-		if (handshake->records[RECORD_MTU].length == 2) {
-			if (as_uint16_endian(&handshake->records[RECORD_MTU], handshake->little_endian) != conf.mtu) {
-				fastd_handshake_send_error(sock, local_addr, remote_addr, peer, handshake, REPLY_UNACCEPTABLE_VALUE, RECORD_MTU);
-				return false;
-			}
-		}
-	}
-
 	if (handshake->type > 1) {
 		if (handshake->records[RECORD_REPLY_CODE].length != 1) {
 			pr_warn("received handshake reply without reply code from %I", remote_addr);
@@ -397,7 +390,18 @@ static inline bool check_records(fastd_socket_t *sock, const fastd_peer_address_
 		}
 
 		if (as_uint8(&handshake->records[RECORD_REPLY_CODE]) != REPLY_SUCCESS) {
-			print_error_reply(remote_addr, handshake);
+			print_error_reply(peer, remote_addr, handshake);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool fastd_handshake_check_mtu(fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const fastd_handshake_t *handshake) {
+	if (handshake->records[RECORD_MTU].length == 2) {
+		if (as_uint16_endian(&handshake->records[RECORD_MTU], handshake->little_endian) != fastd_peer_get_mtu(peer)) {
+			fastd_handshake_send_error(sock, local_addr, remote_addr, peer, handshake, REPLY_UNACCEPTABLE_VALUE, RECORD_MTU);
 			return false;
 		}
 	}