Parsing and using configuration file

.gitignore

@@ -14,6 +14,10 @@ src/Makefile.in
 Makefile
 src/Makefile
 INSTALL
+src/autoconfig.h.in.in
+src/autoconfig.h.in
+src/autoconfig.h
+src/stamp-h1
 
 # build
 *.o

README

@@ -5,25 +5,17 @@ About
 -----
 WrapSix is a fast NAT64 implementation. You also need a DNS64 server (e.g. BIND).
 
-Before compiling, don't forget to configure Wrapsix in files src/wrapper.c and
+Before compiling, don't forget to configure Wrapsix in files src/wrapper.c.
-src/wrapper.h.
 
 Configuration
 -------------
-INTERFACE	Interface on which WrapSix should operate, e.g. eth0.
-PREFIX		NAT64 prefix; at least /96, the default is standard
-		64:ff9b::/96. Input it without the information about prefix
-		length, i.e. just 64:ff9b::.
-IPV4_ADDR	IPv4 address which is dedicated for WrapSix and is not assigned
-		to the host operating system.
 HOST_IPV6_ADDR	IPv6 address which represents the host, i.e. which is assigned
 		to the operating system. It's used in ICMP error messages.
 HOST_IPV4_ADDR	IPv4 address which represents the host, i.e. which is assigned
 		to the operating system. It's used in ICMP error messages.
-MTU		Minimum MTU in your IPv6 network; default is 1280, but you can
+
-		set it to a greater value (up to 1500).
+WrapSix uses configuration file wrapsix.conf from configuration directory set in
-PACKET_BUFFER	Size of a buffer for incoming packets; it's strongly recommended
+"./configure" phase, which is by default /usr/local/etc.
-		to leave its value as is (i.e. 1514).
 
 Installation
 ------------

configure.ac

@@ -14,6 +14,7 @@ AC_CONFIG_FILES([
 	src/Makefile
 ])
 AC_CONFIG_MACRO_DIR([m4])
+AC_CONFIG_HEADER([src/autoconfig.h.in])
 
 ###
 # Configuration options
@@ -26,11 +27,14 @@ AC_ARG_ENABLE([debug],
 
 if test "x$debug" = "xyes"; then
 	AS_COMPILER_FLAGS(AM_CFLAGS, "-g -ggdb -O0 -pipe -pedantic -Wshadow -Wall -Wextra -Wno-missing-field-initializers -Wno-unused-parameter -Wold-style-definition -Wdeclaration-after-statement -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -Wformat-nonliteral -Wformat-security -Wswitch-enum -Winit-self -Wmissing-include-dirs -Wundef -Waggregate-return -Wnested-externs -Wunsafe-loop-optimizations -Winvalid-pch")
-	AC_DEFINE([DEBUG])
+	AC_DEFINE([DEBUG], [], [Turn on debug mode])
 else
         AS_COMPILER_FLAGS(AM_CFLAGS, "-O2")
 fi
 
+
+AC_DEFINE([SYSCONFDIR], "--sysconfdir--", [Configuration files directory])
+
 ###
 # Final commands
 ###

src/Makefile.am

@@ -1,7 +1,9 @@
 sbin_PROGRAMS = wrapsix
 wrapsix_SOURCES = \
 		  arp.c arp.h \
+		  autoconfig.h \
 		  checksum.c checksum.h \
+		  config.c config.h \
 		  ethernet.h \
 		  icmp.c icmp.h \
 		  ipv4.c ipv4.h \
@@ -14,3 +16,6 @@ wrapsix_SOURCES = \
 		  transmitter.c transmitter.h \
 		  udp.c udp.h \
 		  wrapper.c wrapper.h
+
+autoconfig.h:
+	sed -e 's|--sysconfdir--|$(sysconfdir)|' autoconfig.h.in > autoconfig.h

src/config.c

@@ -0,0 +1,183 @@
+/*
+ *  WrapSix
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "config.h"
+#include "log.h"
+#include "wrapper.h"
+
+#define SYNTAX_ERROR(file, line, pos, fatal) { \
+			log_error("Syntax error in configuration file %s on " \
+				  "line %d, position %d", file, line, pos); \
+			fclose(f); \
+			if (fatal) { \
+				exit(1); \
+			} else { \
+				return 1; \
+			} \
+		}
+
+#define	C_DEFAULT_MTU		1280
+#define	C_DEFAULT_INTERFACE	"eth0"
+#define	C_DEFAULT_PREFIX	"64:ff9b::"
+
+/**
+ * Configuration file parser.
+ *
+ * @param	config_file	Configuration file (with path) to parse
+ * @param	cmtu		Pointer to variable where to save MTU
+ * @param	oto		One-time configuration options (used only
+ * 				locally to init other things)
+ * @param	init		0 or 1, whether or not to initialize
+ * 				configuration with defaults
+ */
+int cfg_parse(const char *config_file, unsigned short *cmtu,
+	      struct s_cfg_opts *oto, unsigned char init)
+{
+	FILE *f;
+	unsigned int ln = 0;
+	char c;
+
+	unsigned short opt_len, wht_len, val_len;
+	char tmp_opt[32], tmp_val[128];
+
+	/* set defaults */
+	*cmtu = C_DEFAULT_MTU;
+	/* TODO: get automatically the first available interface */
+	strncpy(oto->interface, C_DEFAULT_INTERFACE, sizeof(oto->interface));
+	strncpy(oto->prefix, C_DEFAULT_PREFIX, sizeof(oto->prefix));
+	oto->ipv4_address[0] = '\0';
+
+	f = fopen(config_file, "r");
+
+	if (f == NULL) {
+		/* set defaults */
+		log_warn("Configuration file %s doesn't exist, using defaults",
+			 config_file);
+
+		if (init) {
+			log_error("IPv4 address unconfigured! Exiting");
+			exit(1);
+		}
+
+		return 0;
+	}
+
+	while (c = getc(f), !feof(f)) {
+		ln++;
+
+		/* comments */
+		if (c == '#') {
+			/* skip this line */
+			while (c = getc(f), c != '\n');
+
+			continue;
+		}
+
+		/* empty lines */
+		if (c == '\n') {
+			continue;
+		}
+
+		/* option is only of small letters */
+		if (c < 'a' || c > 'z') {
+			SYNTAX_ERROR(config_file, ln, 0, init);
+		}
+
+		/* read option */
+		for (opt_len = 0; c != ' ' && c != '\t'; opt_len++,
+		    c = getc(f)) {
+			if (feof(f) || !((c >= 'a' && c <= 'z') || c == '_' ||
+			    (c >= '0' && c <= '9'))) {
+				SYNTAX_ERROR(config_file, ln, opt_len, init);
+			}
+
+			if (opt_len < 32 - 1) {
+				tmp_opt[opt_len] = c;
+			} else {
+				SYNTAX_ERROR(config_file, ln, opt_len, init);
+			}
+		}
+		tmp_opt[opt_len] = '\0';
+
+		/* skip white space */
+		for (wht_len = 0; c == ' ' || c == '\t'; wht_len++,
+		    c = getc(f)) {
+			if (feof(f)) {
+				SYNTAX_ERROR(config_file, ln, opt_len + wht_len,
+					     init);
+			}
+		}
+
+		/* read value */
+		for (val_len = 0; c != ' ' && c != '\t' && c != '\n'; val_len++,
+		    c = getc(f)) {
+			if (feof(f)) {
+				SYNTAX_ERROR(config_file, ln, opt_len, init);
+			}
+
+			if (val_len < 128 - 1) {
+				tmp_val[val_len] = c;
+			} else {
+				SYNTAX_ERROR(config_file, ln, opt_len, init);
+			}
+		}
+		tmp_val[val_len] = '\0';
+
+		/* skip rest of this line */
+		if (c != '\n') {
+			while (c = getc(f), c != '\n');
+		}
+
+		/* recognize the option */
+		if (!strcmp(tmp_opt, "mtu")) {
+			*cmtu = atoi(tmp_val);
+			if (*cmtu > MAX_MTU) {
+				log_warn("MTU setting is over maximum (%d), "
+					 "falling to default value (%d)",
+					 MAX_MTU, C_DEFAULT_MTU);
+				*cmtu = C_DEFAULT_MTU;
+			}
+		} else if (!strcmp(tmp_opt, "interface")) {
+			strncpy(oto->interface, tmp_val, sizeof(oto->interface));
+		} else if (!strcmp(tmp_opt, "prefix")) {
+			strncpy(oto->prefix, tmp_val, sizeof(oto->prefix));
+		} else if (!strcmp(tmp_opt, "ipv4_address")) {
+			if (val_len < sizeof(oto->ipv4_address)) {
+				strncpy(oto->ipv4_address, tmp_val, sizeof(oto->ipv4_address));
+			} else {
+				SYNTAX_ERROR(config_file, ln, opt_len + wht_len, init);
+			}
+		} else {
+			log_error("Unknown configuration option");
+			SYNTAX_ERROR(config_file, ln, 0, init);
+		}
+	}
+
+	fclose(f);
+
+	if (init && oto->ipv4_address[0] == '\0') {
+		log_error("IPv4 address unconfigured! Exiting");
+		exit(1);
+	}
+
+	return 0;
+}

src/config.h

@@ -0,0 +1,31 @@
+/*
+ *  WrapSix
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CONFIG_H
+#define CONFIG_H
+
+struct s_cfg_opts {
+	char interface[128];
+	char prefix[128];
+	char ipv4_address[16];
+};
+
+int cfg_parse(const char *config_file, unsigned short *cmtu,
+	      struct s_cfg_opts *oto, unsigned char init);
+
+#endif /* CONFIG_H */

src/icmp.c

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2013  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -64,7 +64,7 @@ int icmp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4,
 	unsigned char	*icmp_data;
 	struct s_nat	*connection;
 	unsigned short	 orig_checksum;
-	unsigned char	 packet[MTU + sizeof(struct s_ethernet)];
+	unsigned char	 packet[PACKET_BUFFER];
 	unsigned short	 new_len = sizeof(struct s_ethernet) +
 				   sizeof(struct s_ipv6);
 
@@ -119,15 +119,15 @@ int icmp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4,
 			icmp->type = ICMPV6_ECHO_REPLY;
 
 			/* copy the payload data */
-			if (payload_size < MTU - sizeof(struct s_ipv6)) {
+			if (payload_size < mtu - sizeof(struct s_ipv6)) {
 				memcpy(&packet[new_len], payload, payload_size);
 				icmp = (struct s_icmp *) &packet[new_len];
 				new_len += payload_size;
 			} else {
-				memcpy(&packet[new_len], payload, MTU -
+				memcpy(&packet[new_len], payload, mtu -
 				       sizeof(struct s_ipv6));
 				icmp = (struct s_icmp *) &packet[new_len];
-				new_len += MTU - sizeof(struct s_ipv6);
+				new_len += mtu - sizeof(struct s_ipv6);
 			}
 
 			break;
@@ -174,9 +174,9 @@ int icmp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4,
 					if (ntohs(*icmp_extra_s) < 68) {
 						*icmp_extra = htonl(
 							*icmp_extra_s + 20 <
-							MTU ? (unsigned int)
+							mtu ? (unsigned int)
 							*icmp_extra_s + 20 :
-							MTU);
+							(unsigned int) mtu);
 					} else {
 						/* RFC1191 */
 						/* NOTE: >= would cause infinite
@@ -1063,10 +1063,10 @@ int sub_icmp4_error(unsigned char *payload, unsigned short payload_size,
 	/* copy payload, aligned to MTU */
 	/* we can afford to use full MTU instead of just 1280 B as admin
 	 * warrants this to us */
-	if (payload_size > MTU + sizeof(struct s_ethernet) - *packet_len) {
+	if (payload_size > mtu + sizeof(struct s_ethernet) - *packet_len) {
 		memcpy(&packet[*packet_len], payload,
-		       MTU + sizeof(struct s_ethernet) - *packet_len);
+		       mtu + sizeof(struct s_ethernet) - *packet_len);
-		*packet_len = MTU;
+		*packet_len = mtu;
 	} else {
 		memcpy(&packet[*packet_len], payload, payload_size);
 		*packet_len += payload_size;

src/tcp.c

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2013  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -199,8 +199,8 @@ int tcp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4, char *payload,
 
 		/* allocate enough memory for translated packet */
 		if ((packet = (unsigned char *) malloc(
-		    payload_size > MTU - sizeof(struct s_ipv6) ?
+		    payload_size > mtu - sizeof(struct s_ipv6) ?
-		    MTU + sizeof(struct s_ethernet) :
+		    mtu + sizeof(struct s_ethernet) :
 		    sizeof(struct s_ethernet) + sizeof(struct s_ipv6) +
 		    payload_size)) == NULL) {
 			log_error("Lack of free memory");
@@ -233,9 +233,9 @@ int tcp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4, char *payload,
 						     connection->ipv6_port_src);
 
 		/* fragment it or not? */
-		if (payload_size > MTU - sizeof(struct s_ipv6)) {
+		if (payload_size > mtu - sizeof(struct s_ipv6)) {
 			/* 1st fragments' payload size must be 8-byte aligned */
-			#define FRAGMENT_LEN (((MTU - sizeof(struct s_ipv6) - \
+			#define FRAGMENT_LEN (((mtu - sizeof(struct s_ipv6) - \
 				sizeof(struct s_ipv6_fragment)) / 8) * 8)
 
 			/* fill in missing IPv6 header fields */
@@ -341,9 +341,9 @@ int tcp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4, char *payload,
 
 		/* allocate enough memory for translated packet */
 		if ((packet = (unsigned char *) malloc(
-		    payload_size > MTU - sizeof(struct s_ipv6) -
+		    payload_size > mtu - sizeof(struct s_ipv6) -
 		    sizeof(struct s_ipv6_fragment) ?
-		    MTU + sizeof(struct s_ethernet) :
+		    mtu + sizeof(struct s_ethernet) :
 		    sizeof(struct s_ethernet) + sizeof(struct s_ipv6) +
 		    sizeof(struct s_ipv6_fragment) + payload_size)) == NULL) {
 			log_error("Lack of free memory");
@@ -374,7 +374,7 @@ int tcp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4, char *payload,
 		frag->id		= htonl(htons(ip4->id));
 
 		/* fragment the fragment or not? */
-		if (payload_size > MTU - sizeof(struct s_ipv6) -
+		if (payload_size > mtu - sizeof(struct s_ipv6) -
 		    sizeof(struct s_ipv6_fragment)) {
 			/* fill in missing IPv6 header fields */
 			ip6->len = htons(FRAGMENT_LEN +
@@ -391,7 +391,7 @@ int tcp_ipv4(struct s_ethernet *eth4, struct s_ipv4 *ip4, char *payload,
 			       payload, FRAGMENT_LEN);
 
 			/* send translated packet */
-			transmit_raw(packet, sizeof(struct s_ethernet) + MTU);
+			transmit_raw(packet, sizeof(struct s_ethernet) + mtu);
 
 			/* create the second fragment */
 			ip6->len = htons(payload_size +

src/wrapper.c

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2013  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -31,6 +31,10 @@
 #include <unistd.h>		/* close */
 
 #include "arp.h"
+#ifdef HAVE_CONFIG_H
+#include "autoconfig.h"
+#endif /* HAVE_CONFIG_H */
+#include "config.h"
 #include "ethernet.h"
 #include "ipv4.h"
 #include "ipv6.h"
@@ -40,13 +44,11 @@
 #include "wrapper.h"
 
 /* +++ CONFIGURATION +++ */
-#define INTERFACE	"eth0"
-#define PREFIX		"64:ff9b::"
-#define IPV4_ADDR	"192.168.0.111"
 #define HOST_IPV6_ADDR	"fd77::1:0:1"
 #define HOST_IPV4_ADDR	"192.168.0.19"
 /* --- CONFIGURATION --- */
 
+unsigned short mtu;
 
 struct ifreq		interface;
 struct s_mac_addr	mac;
@@ -60,6 +62,8 @@ int process(char *packet);
 
 int main(int argc, char **argv)
 {
+	struct s_cfg_opts	cfg;
+
 	struct packet_mreq	pmr;
 	struct ethtool_value	ethtool;
 
@@ -72,6 +76,18 @@ int main(int argc, char **argv)
 
 	log_info(PACKAGE_STRING " is starting");
 
+	/* load configuration */
+	if (argc == 1) {
+		cfg_parse(SYSCONFDIR "/wrapsix.conf", &mtu, &cfg, 1);
+	} else {
+		cfg_parse(argv[1], &mtu, &cfg, 1);
+	}
+
+	log_info("Using: interface %s", cfg.interface);
+	log_info("       prefix %s", cfg.prefix);
+	log_info("       MTU %d", mtu);
+	log_info("       IPv4 address %s", cfg.ipv4_address);
+
 	/* initialize the socket for sniffing */
 	if ((sniff_sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) ==
 	    -1) {
@@ -80,9 +96,9 @@ int main(int argc, char **argv)
 	}
 
 	/* get the interface */
-	strncpy(interface.ifr_name, INTERFACE, IFNAMSIZ);
+	strncpy(interface.ifr_name, cfg.interface, IFNAMSIZ);
 	if (ioctl(sniff_sock, SIOCGIFINDEX, &interface) == -1) {
-		log_error("Unable to get the interface");
+		log_error("Unable to get the interface %s", cfg.interface);
 		return 1;
 	}
 
@@ -128,10 +144,10 @@ int main(int argc, char **argv)
 	inet_pton(AF_INET6, "ff02::1:ff00:0", &ndp_multicast_addr);
 
 	/* compute binary IPv6 address of WrapSix prefix */
-	inet_pton(AF_INET6, PREFIX, &wrapsix_ipv6_prefix);
+	inet_pton(AF_INET6, cfg.prefix, &wrapsix_ipv6_prefix);
 
 	/* compute binary IPv4 address of WrapSix */
-	inet_pton(AF_INET, IPV4_ADDR, &wrapsix_ipv4_addr);
+	inet_pton(AF_INET, cfg.ipv4_address, &wrapsix_ipv4_addr);
 
 	/* compute binary IPv6 address of WrapSix host */
 	inet_pton(AF_INET6, HOST_IPV6_ADDR, &host_ipv6_addr);

src/wrapper.h

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2012  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2013  xHire <xhire@wrapsix.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -22,11 +22,12 @@
 #include "ipv4.h"
 #include "ipv6.h"
 
-/* +++ CONFIGURE +++ */
+/* +++ INTERNAL CONFIGURATION +++ */
-#define MTU		1280	/* MTU on IPv6 side */
+#define MAX_MTU		1500	/* maximum MTU on IPv6 side */
 #define PACKET_BUFFER	1514	/* buffer for any packet */
-/* --- CONFIGURE --- */
+/* --- INTERNAL CONFIGURATION --- */
 
+extern unsigned short		mtu;
 extern struct ifreq		interface;
 extern struct s_mac_addr	mac;
 extern struct s_ipv6_addr	ndp_multicast_addr;