Partial implementation of a config files parser

12 files changed, 365 insertions, 43 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index da8027e..ed04b15 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,9 @@ project(FASTD C)
 
 set(CMAKE_MODULE_PATH ${FASTD_SOURCE_DIR})
 
+find_package(BISON REQUIRED)
+find_package(FLEX REQUIRED)
+
 find_package(UECC)
 find_package(NaCl)
 
diff --git a/FindFLEX.cmake b/FindFLEX.cmake
new file mode 100644
index 0000000..fe83369
--- /dev/null
+++ b/FindFLEX.cmake
@@ -0,0 +1,120 @@
+#=============================================================================
+# Copyright 2009 Kitware, Inc.
+# Copyright 2006 Tristan Carel
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 
+# * Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+# 
+# * 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.
+# 
+# * Neither the names of Kitware, Inc., the Insight Software Consortium,
+#   nor the names of their contributors may be used to endorse or promote
+#   products derived from this software without specific prior written
+#   permission.
+# 
+# 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.
+# 
+# ------------------------------------------------------------------------------
+# 
+# The above copyright and license notice applies to distributions of
+# CMake in source and binary form.  Some source files contain additional
+# notices of original copyright by their contributors; see each source
+# for details.  Third-party software packages supplied with CMake under
+# compatible licenses provide their own copyright notices documented in
+# corresponding subdirectories.
+#=============================================================================
+
+FIND_PROGRAM(FLEX_EXECUTABLE flex DOC "path to the flex executable")
+MARK_AS_ADVANCED(FLEX_EXECUTABLE)
+
+FIND_LIBRARY(FL_LIBRARY NAMES fl
+  DOC "Path to the fl library")
+
+FIND_PATH(FLEX_INCLUDE_DIR FlexLexer.h
+  DOC "Path to the flex headers")
+
+MARK_AS_ADVANCED(FL_LIBRARY FLEX_INCLUDE_DIR)
+
+SET(FLEX_INCLUDE_DIRS ${FLEX_INCLUDE_DIR})
+SET(FLEX_LIBRARIES ${FL_LIBRARY})
+
+IF(FLEX_EXECUTABLE)
+
+  EXECUTE_PROCESS(COMMAND ${FLEX_EXECUTABLE} --version
+    OUTPUT_VARIABLE FLEX_version_output
+    ERROR_VARIABLE FLEX_version_error
+    RESULT_VARIABLE FLEX_version_result
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  IF(NOT ${FLEX_version_result} EQUAL 0)
+    IF(FLEX_FIND_REQUIRED)
+      MESSAGE(SEND_ERROR "Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}")
+    ELSE()
+      MESSAGE("Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}\nFLEX_VERSION will not be available")
+    ENDIF()
+  ELSE()
+    STRING(REGEX REPLACE "^flex (.*)$" "\\1"
+      FLEX_VERSION "${FLEX_version_output}")
+  ENDIF()
+
+  #============================================================
+  # FLEX_TARGET (public macro)
+  #============================================================
+  #
+  MACRO(FLEX_TARGET Name Input Output)
+    SET(FLEX_TARGET_usage "FLEX_TARGET(<Name> <Input> <Output> [COMPILE_FLAGS <string>]")
+    IF(${ARGC} GREATER 3)
+      IF(${ARGC} EQUAL 5)
+        IF("${ARGV3}" STREQUAL "COMPILE_FLAGS")
+          SET(FLEX_EXECUTABLE_opts  "${ARGV4}")
+          SEPARATE_ARGUMENTS(FLEX_EXECUTABLE_opts)
+        ELSE()
+          MESSAGE(SEND_ERROR ${FLEX_TARGET_usage})
+        ENDIF()
+      ELSE()
+        MESSAGE(SEND_ERROR ${FLEX_TARGET_usage})
+      ENDIF()
+    ENDIF()
+
+    STRING(REGEX REPLACE "^(.*)(\\.[^.]*)$" "\\2" _fileext "${Output}")
+    STRING(REPLACE "c" "h" _fileext ${_fileext})
+    STRING(REGEX REPLACE "^(.*)(\\.[^.]*)$" "\\1${_fileext}"
+       OutputHeader "${Output}")
+
+    ADD_CUSTOM_COMMAND(OUTPUT ${Output} ${OutputHeader}
+      COMMAND ${FLEX_EXECUTABLE}
+      ARGS ${FLEX_EXECUTABLE_opts} -o${Output} --header-file=${OutputHeader} ${Input}
+      DEPENDS ${Input}
+      COMMENT "[FLEX][${Name}] Building scanner with flex ${FLEX_VERSION}"
+      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+
+    SET(FLEX_${Name}_DEFINED TRUE)
+    SET(FLEX_${Name}_OUTPUTS ${Output} ${OutputHeader})
+    SET(FLEX_${Name}_OUTPUT_HEADER ${OutputHeader})
+    SET(FLEX_${Name}_INPUT ${Input})
+    SET(FLEX_${Name}_COMPILE_FLAGS ${FLEX_EXECUTABLE_opts})
+  ENDMACRO(FLEX_TARGET)
+  #============================================================
+
+
+ENDIF(FLEX_EXECUTABLE)
+
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(FLEX REQUIRED_VARS FLEX_EXECUTABLE
+                                       VERSION_VAR FLEX_VERSION)
+
+# FindFLEX.cmake ends here
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 223c62a..1da7d13 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(METHODS method_null.c)
-set(FASTD_INCLUDES ${FASTD_BINARY_DIR})
+set(FASTD_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR} ${FASTD_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR})
 set(FASTD_LIBS "")
 
 if(WITH_METHOD_ECFXP)
@@ -10,5 +10,19 @@ endif(WITH_METHOD_ECFXP)
 
 include_directories(${FASTD_INCLUDES})
 
-add_executable(fastd fastd.c configure.c handshake.c peer.c printf.c queue.c task.c ${METHODS})
+FLEX_TARGET(fastd_config_lex config.l ${CMAKE_CURRENT_BINARY_DIR}/config.ll.c)
+BISON_TARGET(fastd_config_parse config.y ${CMAKE_CURRENT_BINARY_DIR}/config.yy.c)
+
+add_executable(fastd
+  fastd.c
+  config.c
+  handshake.c
+  peer.c
+  printf.c
+  queue.c
+  task.c
+  ${FLEX_fastd_config_lex_OUTPUTS}
+  ${BISON_fastd_config_parse_OUTPUTS}
+  ${METHODS}
+)
 target_link_libraries(fastd rt ${FASTD_LIBS})
diff --git a/src/configure.c b/src/config.c
index 7473696..18fe120 100644
--- a/src/configure.c
+++ b/src/config.c
@@ -27,6 +27,8 @@
 
 #include "fastd.h"
 #include "peer.h"
+#include <config.ll.h>
+#include <config.yy.h>
 
 #include <config.h>
 
@@ -52,16 +54,16 @@ static void default_config(fastd_config *conf) {
 
 	memset(&conf->bind_addr_in, 0, sizeof(struct sockaddr_in));
 	conf->bind_addr_in.sin_family = AF_UNSPEC;
-	conf->bind_addr_in.sin_port = htons(1337);
+	conf->bind_addr_in.sin_port = 0;
 	conf->bind_addr_in.sin_addr.s_addr = htonl(INADDR_ANY);
 
 	memset(&conf->bind_addr_in6, 0, sizeof(struct sockaddr_in6));
 	conf->bind_addr_in6.sin6_family = AF_UNSPEC;
-	conf->bind_addr_in6.sin6_port = htons(1337);
+	conf->bind_addr_in6.sin6_port = 0;
 	conf->bind_addr_in6.sin6_addr = in6addr_any;
 
 	conf->mtu = 1500;
-	conf->protocol = PROTOCOL_ETHERNET;
+	conf->mode = MODE_TAP;
 	conf->method = &fastd_method_null;
 	conf->peers = NULL;
 }
@@ -85,6 +87,21 @@ static bool config_match(const char *opt, ...) {
 	return match;
 }
 
+static void fastd_read_config(fastd_context *ctx, fastd_config *conf, const char *filename) {
+	yyscan_t scanner;
+	FILE *file;
+
+	file = fopen(filename, "r");
+	fastd_config_lex_init(&scanner);
+
+	fastd_config_set_in(file, scanner);
+
+	fastd_config_parse(ctx, conf, scanner);
+
+	fastd_config_lex_destroy(scanner);
+	fclose(file);
+}
+
 #define IF_OPTION(args...) if(config_match(argv[i], args, NULL) && (++i))
 #define IF_OPTION_ARG(args...) if(config_match(argv[i], args, NULL) && ({ \
 				arg = argv[i+1];			\
@@ -114,6 +131,11 @@ void fastd_configure(fastd_context *ctx, fastd_config *conf, int argc, char *con
 
 
 	while (i < argc) {
+		IF_OPTION_ARG("-c", "--config") {
+			fastd_read_config(ctx, conf, arg);
+			continue;
+		}
+
 		IF_OPTION_ARG("-i", "--interface") {
 			conf->ifname = arg;
 			continue;
@@ -180,18 +202,18 @@ void fastd_configure(fastd_context *ctx, fastd_config *conf, int argc, char *con
 			continue;
 		}
 
-		IF_OPTION_ARG("-P", "--protocol") {
-			if (!strcmp(arg, "ethernet"))
-				conf->protocol = PROTOCOL_ETHERNET;
-			else if (!strcmp(arg, "ip"))
-				conf->protocol = PROTOCOL_IP;
+		IF_OPTION_ARG("-m", "--mode") {
+			if (!strcmp(arg, "tap"))
+				conf->mode = MODE_TAP;
+			else if (!strcmp(arg, "tun"))
+				conf->mode = MODE_TUN;
 			else
-				exit_error(ctx, "invalid protocol `%s'", arg);
+				exit_error(ctx, "invalid mode `%s'", arg);
 			continue;
 		}
 
 
-		IF_OPTION_ARG("-m", "--method") {
+		IF_OPTION_ARG("-P", "--protocol") {
 			if (!strcmp(arg, "null"))
 				conf->method = &fastd_method_null;
 #ifdef WITH_METHOD_ECFXP
@@ -199,7 +221,7 @@ void fastd_configure(fastd_context *ctx, fastd_config *conf, int argc, char *con
 				conf->method = &fastd_method_ec25519_fhmqvc_xsalsa20_poly1305;
 #endif
 			else
-				exit_error(ctx, "invalid method `%s'", arg);
+				exit_error(ctx, "invalid protocol `%s'", arg);
 			continue;
 		}
 
@@ -281,8 +303,8 @@ void fastd_configure(fastd_context *ctx, fastd_config *conf, int argc, char *con
 	}
 
 	bool ok = true;
-	if (conf->protocol == PROTOCOL_IP && (!conf->peers || conf->peers->next)) {
-		pr_error(ctx, "for protocol `ip' exactly one peer must be configured");
+	if (conf->mode == MODE_TUN && (!conf->peers || conf->peers->next)) {
+		pr_error(ctx, "for tun mode exactly one peer must be configured");
 		ok = false;
 	}
 
diff --git a/src/config.l b/src/config.l
new file mode 100644
index 0000000..e9dd235
--- /dev/null
+++ b/src/config.l
@@ -0,0 +1,57 @@
+%option prefix="fastd_config_"
+%option noyywrap
+%option bison-bridge
+%option reentrant
+
+%top {
+	 #include <fastd.h>
+	 #include <config.yy.h>
+	 #define YY_DECL int fastd_config_lex(YYSTYPE *yylval_param, fastd_context *ctx, void *yyscanner)
+}
+
+%x STRING
+%x ADDR6
+
+%%
+[0-9]+		{ yylval->num = atoi(yytext); return TOK_INTEGER; }
+
+interface	{ yylval->str = yytext; return TOK_INTERFACE; }
+bind		{ yylval->str = yytext; return TOK_BIND; }
+mtu		{ yylval->str = yytext; return TOK_MTU; }
+mode		{ yylval->str = yytext; return TOK_MODE; }
+protocol	{ yylval->str = yytext; return TOK_PROTOCOL; }
+peer		{ yylval->str = yytext; return TOK_PEER; }
+
+[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3} {
+			if (!inet_pton(AF_INET, yytext, &yylval->addr))
+				exit_error(ctx, "config error: invalid address");
+
+			return TOK_ADDR;
+		}
+
+any		{ yylval->str = yytext; return TOK_ANY; }
+float		{ yylval->str = yytext; return TOK_FLOAT; }
+tap		{ yylval->str = yytext; return TOK_TAP; }
+tun		{ yylval->str = yytext; return TOK_TUN; }
+
+[A-Za-z_][A-Za-z0-9_]* { yylval->str = yytext; return TOK_IDENTIFIER; }
+
+[;:\{\}]	{ return *yytext; }
+
+[ \t\n]	;
+
+\"		BEGIN(STRING);
+<STRING>[^"]*	{ yylval->str = yytext; return TOK_STRING; }
+<STRING>\"	BEGIN(INITIAL);
+
+\[		BEGIN(ADDR6);
+<ADDR6>[^\]]+		{
+				if (!inet_pton(AF_INET6, yytext, &yylval->addr6))
+					exit_error(ctx, "config error: invalid address");
+
+				return TOK_ADDR6;
+			}
+<ADDR6>\]		BEGIN(INITIAL);
+
+<INITIAL,STRING,ADDR6>.		exit_error(ctx, "config error: invalid character");
+%%
diff --git a/src/config.y b/src/config.y
new file mode 100644
index 0000000..08c5050
--- /dev/null
+++ b/src/config.y
@@ -0,0 +1,106 @@
+%define api.pure
+%name-prefix "fastd_config_"
+%lex-param {fastd_context *ctx}
+%lex-param {yyscan_t scanner}
+%parse-param {fastd_context *ctx}
+%parse-param {fastd_config *config}
+%parse-param {yyscan_t scanner}
+
+%code requires {
+	#include <arpa/inet.h>
+}
+
+%union {
+	int num;
+	char* str;
+	struct in_addr addr;
+	struct in6_addr addr6;
+}
+
+%token <num> TOK_INTEGER
+%token <str> TOK_STRING
+%token <str> TOK_IDENTIFIER
+
+%token <str> TOK_INTERFACE
+%token <str> TOK_BIND
+%token <str> TOK_MTU
+%token <str> TOK_MODE
+%token <str> TOK_PROTOCOL
+%token <str> TOK_PEER
+
+%token <addr> TOK_ADDR
+%token <addr6> TOK_ADDR6
+
+%token <str> TOK_ANY
+%token <str> TOK_FLOAT
+%token <str> TOK_TAP
+%token <str> TOK_TUN
+
+/*			%code top {
+	#define YY_DECL int fastd_config_lex(YYSTYPE *yylval_param, fastd_context *ctx, yyscan_t yyscanner)
+}*/			
+
+
+%code {
+	#include <config.ll.h>
+	YY_DECL;
+
+	void fastd_config_error(fastd_context *ctx, fastd_config *config, void *scanner, char *s);
+}
+
+%code provides {
+	 #include <fastd.h>
+	int fastd_config_parse (fastd_context *ctx, fastd_config *config, void *scanner);
+}
+
+%%
+config:		config statement
+	|
+	;
+
+statement:	TOK_INTERFACE interface ';'
+	| 	TOK_BIND bind ';'
+	|	TOK_MTU mtu ';'
+	|	TOK_MODE mode ';'
+	|	TOK_PROTOCOL protocol ';'
+	|	TOK_PEER peer '{' peer_config '}'
+	;
+
+interface:	TOK_STRING	{ config->ifname = strdup($1); }
+	;
+
+bind:		TOK_ADDR
+	|	TOK_ADDR ':' port
+	|	TOK_ADDR6
+	|	TOK_ADDR6 ':' port
+	|	TOK_ANY
+	|	TOK_ANY ':' port
+	;
+
+mtu:		TOK_INTEGER	{ config->mtu = $1; }
+	;
+
+mode:		TOK_TAP	{ config->mode = MODE_TAP; }
+	|	TOK_TUN	{ config->mode = MODE_TUN; }
+	;
+
+protocol:	TOK_STRING
+	;
+
+peer:		TOK_STRING
+	|
+	;
+
+peer_config:	peer_config peer_statement
+	|
+	;
+
+peer_statement: ':'
+	;
+
+port:		TOK_INTEGER
+	;
+%%
+void fastd_config_error(fastd_context *ctx, fastd_config *config, yyscan_t scanner, char *s) {
+	exit_error(ctx, "config error: %s", s);
+}
diff --git a/src/fastd.c b/src/fastd.c
index cae7c64..3b27e98 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -53,17 +53,17 @@ static void init_tuntap(fastd_context *ctx) {
 	if (ctx->conf->ifname)
 		strncpy(ifr.ifr_name, ctx->conf->ifname, IF_NAMESIZE-1);
 
-	switch (ctx->conf->protocol) {
-	case PROTOCOL_ETHERNET:
+	switch (ctx->conf->mode) {
+	case MODE_TAP:
 		ifr.ifr_flags = IFF_TAP;
 		break;
 
-	case PROTOCOL_IP:
+	case MODE_TUN:
 		ifr.ifr_flags = IFF_TUN;
 		break;
 
 	default:
-		exit_bug(ctx, "invalid protocol");
+		exit_bug(ctx, "invalid mode");
 	}
 
 	ifr.ifr_flags |= IFF_NO_PI;
@@ -166,7 +166,7 @@ static void handle_tasks(fastd_context *ctx) {
 			break;
 
 		case TASK_HANDLE_RECV:
-			if (ctx->conf->protocol == PROTOCOL_ETHERNET) {
+			if (ctx->conf->mode == MODE_TAP) {
 				const fastd_eth_addr *src_addr = fastd_get_source_address(ctx, task->handle_recv.buffer);
 
 				if (fastd_eth_addr_is_unicast(src_addr))
@@ -208,7 +208,7 @@ static void handle_tun(fastd_context *ctx) {
 
 	fastd_peer *peer = NULL;
 
-	if (ctx->conf->protocol == PROTOCOL_ETHERNET) {
+	if (ctx->conf->mode == MODE_TAP) {
 		const fastd_eth_addr *dest_addr = fastd_get_dest_address(ctx, buffer);
 		if (fastd_eth_addr_is_unicast(dest_addr)) {
 			peer = fastd_peer_find_by_eth_addr(ctx, dest_addr);
diff --git a/src/fastd.h b/src/fastd.h
index c42baa3..4af9f20 100644
--- a/src/fastd.h
+++ b/src/fastd.h
@@ -87,7 +87,7 @@ struct _fastd_config {
 	struct sockaddr_in6 bind_addr_in6;
 
 	uint16_t mtu;
-	fastd_protocol protocol;
+	fastd_mode mode;
 
 	fastd_method *method;
 
@@ -153,13 +153,13 @@ static inline void fastd_buffer_free(fastd_buffer buffer) {
 }
 
 static inline size_t fastd_max_packet_size(const fastd_context *ctx) {
-	switch (ctx->conf->protocol) {
-	case PROTOCOL_ETHERNET:
+	switch (ctx->conf->mode) {
+	case MODE_TAP:
 		return ctx->conf->mtu+ETH_HLEN;
-	case PROTOCOL_IP:
+	case MODE_TUN:
 		return ctx->conf->mtu;
 	default:
-		exit_bug(ctx, "invalid protocol");
+		exit_bug(ctx, "invalid mode");
 	}
 }
 
diff --git a/src/handshake.c b/src/handshake.c
index e30ab9f..19f15a9 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -74,8 +74,8 @@ void fastd_handshake_send(fastd_context *ctx, fastd_peer *peer) {
 	request->req_id = ++peer->last_req_id;
 	request->rsv = 0;
 
-	uint8_t protocol = ctx->conf->protocol;
-	handshake_add(ctx, &buffer, RECORD_PROTOCOL, 1, &protocol);
+	uint8_t mode = ctx->conf->mode;
+	handshake_add(ctx, &buffer, RECORD_MODE, 1, &mode);
 
 	handshake_add(ctx, &buffer, RECORD_METHOD_NAME, method_len, ctx->conf->method->name);
 
@@ -119,15 +119,15 @@ void fastd_handshake_handle(fastd_context *ctx, fastd_peer *peer, fastd_buffer b
 		uint8_t reply_code = REPLY_SUCCESS;
 		uint8_t error_detail = 0;
 
-		if (!records[RECORD_PROTOCOL]) {
+		if (!records[RECORD_MODE]) {
 			reply_code = REPLY_MANDATORY_MISSING;
-			error_detail = RECORD_PROTOCOL;
+			error_detail = RECORD_MODE;
 			goto send_reply;
 		}
 
-		if (lengths[RECORD_PROTOCOL] != 1 || *(uint8_t*)records[RECORD_PROTOCOL] != ctx->conf->protocol) {
+		if (lengths[RECORD_MODE] != 1 || *(uint8_t*)records[RECORD_MODE] != ctx->conf->mode) {
 			reply_code = REPLY_UNACCEPTABLE_VALUE;
-			error_detail = RECORD_PROTOCOL;
+			error_detail = RECORD_MODE;
 			goto send_reply;
 		}
 
diff --git a/src/packet.h b/src/packet.h
index d442d18..b206663 100644
--- a/src/packet.h
+++ b/src/packet.h
@@ -42,7 +42,7 @@ typedef enum _fastd_handshake_record_type {
 	RECORD_REPLY_CODE = 0,
 	RECORD_ERROR_DETAIL,
 	RECORD_FLAGS,
-	RECORD_PROTOCOL,
+	RECORD_MODE,
 	RECORD_METHOD_NAME,
 	RECORD_MAX,
 } fastd_handshake_record_type;
diff --git a/src/peer.c b/src/peer.c
index ab09a1a..3aecdc0 100644
--- a/src/peer.c
+++ b/src/peer.c
@@ -32,20 +32,20 @@
 
 
 const fastd_eth_addr* fastd_get_source_address(const fastd_context *ctx, fastd_buffer buffer) {
-	switch (ctx->conf->protocol) {
-	case PROTOCOL_ETHERNET:
+	switch (ctx->conf->mode) {
+	case MODE_TAP:
 		return (fastd_eth_addr*)&((struct ethhdr*)buffer.data)->h_source;
 	default:
-		exit_bug(ctx, "invalid protocol");
+		exit_bug(ctx, "invalid mode");
 	}
 }
 
 const fastd_eth_addr* fastd_get_dest_address(const fastd_context *ctx, fastd_buffer buffer) {
-	switch (ctx->conf->protocol) {
-	case PROTOCOL_ETHERNET:
+	switch (ctx->conf->mode) {
+	case MODE_TAP:
 		return (fastd_eth_addr*)&((struct ethhdr*)buffer.data)->h_dest;
 	default:
-		exit_bug(ctx, "invalid protocol");
+		exit_bug(ctx, "invalid mode");
 	}
 }
 
diff --git a/src/types.h b/src/types.h
index af577e3..61417fc 100644
--- a/src/types.h
+++ b/src/types.h
@@ -42,10 +42,10 @@ typedef enum _fastd_loglevel {
 	LOG_DEBUG,
 } fastd_loglevel;
 
-typedef enum _fastd_protocol {
-	PROTOCOL_ETHERNET,
-	PROTOCOL_IP,
-} fastd_protocol;
+typedef enum _fastd_mode {
+	MODE_TAP,
+	MODE_TUN,
+} fastd_mode;
 
 typedef enum _fastd_peer_state {
 	STATE_WAIT,