further IPv6 changes

src/Makefile

@@ -9,7 +9,7 @@ ARCH = `uname -m`
 HEAD_COMMIT = `git rev-parse --short HEAD`
 
 LIBPATH = -L.
-LDFLAGS +=  -lz `sh osflags $(TARGETOS) link` $(LIBPATH)
+LDFLAGS +=  -lz `sh osflags $(TARGETOS) link` $(LIBPATH) -lm
 CFLAGS += -std=c99 -c -g -Wall -D$(OS) -pedantic `sh osflags $(TARGETOS) cflags` -DGITREVISION=\"$(HEAD_COMMIT)\"
 CFLAGS += -Wstrict-prototypes -Wtype-limits -Wmissing-declarations -Wmissing-prototypes
 

src/client.c

@@ -28,6 +28,8 @@
 #include <fcntl.h>
 #include <zlib.h>
 #include <time.h>
+#include <stdbool.h>
+
 
 #ifdef WINDOWS32
 #include "windows.h"
@@ -101,6 +103,7 @@ static time_t lastdownstreamtime;
 static long send_query_sendcnt = -1;
 static long send_query_recvcnt = 0;
 static int hostname_maxlen = 0xFF;
+static bool use_v6 = false;
 
 void
 client_init()
@@ -1374,7 +1377,7 @@ handshake_version(int dns_fd, int *seed)
 }
 
 static int
-handshake_login(int dns_fd, int seed, int forward_v6)
+handshake_login(int dns_fd, int seed)
 {
 	char in[4096];
 	char login[16];
@@ -1405,7 +1408,7 @@ handshake_login(int dns_fd, int seed, int forward_v6)
 
 				server[64] = 0;
 				client[64] = 0;
-				if (tun_setip(client, server, netmask, forward_v6) == 0 &&
+				if (tun_setip(client, server, netmask) == 0 &&
 					tun_setmtu(mtu) == 0) {
 
 					fprintf(stderr, "Server tunnel IP is %s\n", server);
@@ -2326,7 +2329,7 @@ handshake_set_fragsize(int dns_fd, int fragsize)
 }
 
 int
-client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsize, int forward_v6)
+client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsize)
 {
 	int seed;
 	int upcodec;
@@ -2349,7 +2352,7 @@ client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsiz
 		return r;
 	}
 
-	r = handshake_login(dns_fd, seed, forward_v6);
+	r = handshake_login(dns_fd, seed);
 	if (r) {
 		return r;
 	}
@@ -2414,8 +2417,72 @@ client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsiz
 		handshake_set_fragsize(dns_fd, fragsize);
 		if (!running)
 			return -1;
+
+		handshake_check_v6(dns_fd);
+		if (!running)
+			return -1;
 	}
 
 	return 0;
 }
 
+static
+void send_v6_probe(int dns_fd)
+{
+  char data[4096];
+
+	data[0] = userid;
+
+	send_packet(dns_fd, 'g', data, sizeof(data));
+}
+
+int
+handshake_check_v6(int dns_fd)
+{
+	char in[4096];
+	char server6[1024];
+	char client6[1024];
+	int i;
+	int read;
+	int netmask6 = 0;
+
+	fprintf(stderr, "Autoprobing server IPV6 tunnel support\n");
+
+	for (i = 0; running && i < 5; i++) {
+
+     send_v6_probe(dns_fd);
+
+     read = handshake_waitdns(dns_fd, in, sizeof(in), 'g', 'G', i+1);
+
+		 if (read > 0) {
+
+        /*
+			   * including a terminating dash to allow for future IPv6 options, e.g.
+			   * netmask. Currently assumes /64. MTU is taken from the IPv4 handshake.
+			   * A future IPv6-only implementation would need to pass mtu
+			   * in the IPV6 handshake.
+			   */
+
+			  if (sscanf(in, "%512[^-]-%512[^-]-%d", server6, client6, &netmask6) == 3) {
+
+					 fprintf(stderr, "Server tunnel IPv6 is %s\n", server6);
+					 fprintf(stderr, "Local tunnel IPv6 is %s\n", client6);
+
+					 if (tun_setip6(client6, server6, netmask6) == 0) {
+
+              use_v6 = true;
+							return 0;
+				   } else {
+				      errx(4, "Failed to set IPv6 tunnel address");
+				   }
+			  } else {
+				   fprintf(stderr, "Received bad IPv6 tunnel handshake\n");
+			  }
+		 }
+
+		 fprintf(stderr, "Retrying IPv6 tunnel handshake...\n");
+	}
+	if (!running)
+		return -1;
+   return 0;
+}

src/client.h

@@ -35,7 +35,7 @@ void client_set_lazymode(int lazy_mode);
 void client_set_hostname_maxlen(int i);
 
 int client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size,
-		     int fragsize, int forward_v6);
+		     int fragsize);
 int client_tunnel(int tun_fd, int dns_fd);
-
+int handshake_check_v6(int tun_fd);
 #endif

src/common.c

@@ -13,6 +13,8 @@
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ *
  */
 
 #include <time.h>
@@ -557,3 +559,17 @@ fd_set_close_on_exec(int fd)
 }
 #endif
 
+bool
+isV6AddrSet(struct in6_addr *ip6)
+{
+       int i;
+
+       for (i = 0; i < sizeof(ip6->s6_addr); i++) {
+          if (ip6->s6_addr[i] != 0) { 
+             return true;
+          }
+       }
+       
+       return false;
+}
+

src/common.h

@@ -33,6 +33,7 @@
 extern const unsigned char raw_header[RAW_HDR_LEN];
 
 #include <stdarg.h>
+#include <stdbool.h>
 #ifdef WINDOWS32
 #include "windows.h"
 #else
@@ -129,6 +130,7 @@ void read_password(char*, size_t);
 int check_topdomain(char *, int, char **);
 
 int query_datalen(const char *qname, const char *topdomain);
+bool isV6AddrSet(struct in6_addr *);
 
 #if defined(WINDOWS32) || defined(ANDROID)
 #ifndef ANDROID

src/iodine.c

@@ -72,7 +72,7 @@ static void help(FILE *stream, bool verbose)
 {
 	fprintf(stream,
 		"iodine IP over DNS tunneling client\n\n"
-		"Usage: %s [-46fhrvS] [-u user] [-t chrootdir] [-d device] [-P password]\n"
+		"Usage: %s [-46fhrv] [-u user] [-t chrootdir] [-d device] [-P password]\n"
 		"              [-m maxfragsize] [-M maxlen] [-T type] [-O enc] [-L 0|1] [-I sec]\n"
 		"              [-z context] [-F pidfile] [nameserver] topdomain\n", __progname);
 
@@ -100,7 +100,6 @@ static void help(FILE *stream, bool verbose)
 		"  -t dir to chroot to directory dir\n"
 		"  -d device to set tunnel device name\n"
 		"  -z context, to apply specified SELinux context after initialization\n"
-                "  -S enable forwarding of IPv6 packets within the tunnel\n"
 		"  -F pidfile to write pid to a file\n\n"
 		"nameserver is the IP number/hostname of the relaying nameserver. If absent,\n"
 		"           /etc/resolv.conf is used\n"
@@ -153,7 +152,6 @@ int main(int argc, char **argv)
 	struct sockaddr_storage nameservaddr;
 	int nameservaddr_len;
 	int nameserv_family;
-        int forward_v6;
 
 	nameserv_host = NULL;
 	topdomain = NULL;
@@ -178,7 +176,6 @@ int main(int argc, char **argv)
 	selecttimeout = 4;
 	hostname_maxlen = 0xFF;
 	nameserv_family = AF_UNSPEC;
-        forward_v6 = 0;
 
 #ifdef WINDOWS32
 	WSAStartup(req_version, &wsa_data);
@@ -195,7 +192,8 @@ int main(int argc, char **argv)
 		__progname++;
 #endif
 
-	while ((choice = getopt(argc, argv, "t:d:R:P:m:M:z:F:T:O:L:I:46vfhruS")) != -1) {
+	while ((choice = getopt(argc, argv, "46vfhru:t:d:R:P:m:M:F:T:O:L:I:")) != -1) {
+
 		switch(choice) {
 		case '4':
 			nameserv_family = AF_INET;
@@ -220,9 +218,6 @@ int main(int argc, char **argv)
 		case 'u':
 			username = optarg;
 			break;
-                case 'S':
-                        forward_v6 = 1;
-                        break;
 		case 't':
 			newroot = optarg;
 			break;
@@ -372,7 +367,7 @@ int main(int argc, char **argv)
 	fprintf(stderr, "Sending DNS queries for %s to %s\n",
 		topdomain, format_addr(&nameservaddr, nameservaddr_len));
 
-	if (client_handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size, forward_v6)) {
+	if (client_handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size)) {
 		retval = 1;
 		goto cleanup2;
 	}

src/iodined.c

@@ -88,10 +88,16 @@ static int created_users;
 static int check_ip;
 static int my_mtu;
 static in_addr_t my_ip;
+
+char display_ip6[INET6_ADDRSTRLEN];
+char *display_ip6_buffer;
+char *ip6_netmask_buffer;
+
+static struct in6_addr my_ip6;
 static int netmask;
+static int ip6_netmask = 64;
 
 static in_addr_t ns_ip;
-
 static int bind_port;
 static int debug;
 
@@ -658,9 +664,9 @@ static int tunnel_tun(int tun_fd, struct dnsfd *dns_fds)
 
 	/* find target ip in packet, in is padded with 4 bytes TUN header */
 	header = (struct ip*) (in + 4);
-	ip_version = in[4] & 0xf0;
+	ip_version = get_ipversion(in[4]);
 
-	if (ip_version == 64) { /* IPv4 */
+	if (ip_version == 4) { /* IPv4 */
 	     header = (struct ip*) (in + 4);
 	     userid = find_user_by_ip(header->ip_dst.s_addr);
 	} else { /* IPv6 */
@@ -674,6 +680,7 @@ static int tunnel_tun(int tun_fd, struct dnsfd *dns_fds)
 		return 0;
 
 	outlen = sizeof(out);
+
 	compress2((uint8_t*)out, &outlen, (uint8_t*)in, read, 9);
 
 	if (users[userid].conn == CONN_DNS_NULL) {
@@ -1303,6 +1310,32 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 		    !users[userid].lazy)
 			send_chunk_or_dataless(dns_fd, userid, &users[userid].q);
 
+  /* IPv6 tunnel address probe */
+  } else if (in[0] == 'G' || in[0] == 'g') {
+    char client_ip6[INET6_ADDRSTRLEN];
+		char display_my_ip6[INET6_ADDRSTRLEN];
+
+		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, &base32_ops);
+		if (read < 1) {
+			write_dns(dns_fd, q, "BADLEN", 6, 'T');
+			return;
+		}
+
+		/* Ping packet, store userid */
+		userid = unpacked[0];
+		if (check_authenticated_user_and_ip(userid, q) != 0) {
+			write_dns(dns_fd, q, "BADIP", 5, 'T');
+			return; /* illegal id */
+		}
+
+		inet_ntop(AF_INET6, &users[userid].tun_ip6, client_ip6, INET6_ADDRSTRLEN);
+		inet_ntop(AF_INET6, &my_ip6, display_my_ip6, INET6_ADDRSTRLEN);
+		read = snprintf(out, sizeof(out), "%s-%s-%d-",
+				display_my_ip6, client_ip6, ip6_netmask);
+
+		write_dns(dns_fd, q, out, read, users[userid].downenc);
+    return;
+
 	} else if ((in[0] >= '0' && in[0] <= '9')
 			|| (in[0] >= 'a' && in[0] <= 'f')
 			|| (in[0] >= 'A' && in[0] <= 'F')) {
@@ -2288,10 +2321,10 @@ write_dns(int fd, struct query *q, const char *data, int datalen, char downenc)
 static void print_usage(FILE *stream)
 {
 	fprintf(stream,
-		"Usage: %s [-46cDfsvS] [-u user] [-t chrootdir] [-d device] [-m mtu]\n"
+		"Usage: %s [-46cDfsv] [-u user] [-t chrootdir] [-d device] [-m mtu]\n"
 		"               [-z context] [-l ipv4 listen address] [-L ipv6 listen address]\n"
 		"               [-p port] [-n auto|external_ip] [-b dnsport] [-P password]\n"
-		"               [-F pidfile] [-i max idle time] tunnel_ip[/netmask] topdomain\n",
+		"               [-F pidfile] [-S ipv6 tunnel address] [-i max idle time] tunnel_ip[/netmask] topdomain\n",
 		__progname);
 }
 
@@ -2333,7 +2366,7 @@ static void help(FILE *stream)
 		"  -b port to forward normal DNS queries to (on localhost)\n"
 		"  -P password used for authentication (max 32 chars will be used)\n"
 		"  -F pidfile to write pid to a file\n"
-		"  -S enable forwarding of IPv6 packets within the tunnel\n"
+		"  -S IPv6 server address within the tunnel. Netmask fixed at /64\n"
 		"  -i maximum idle time before shutting down\n\n"
 		"tunnel_ip is the IP number of the local tunnel interface.\n"
 		"   /netmask sets the size of the tunnel network.\n"
@@ -2405,7 +2438,6 @@ main(int argc, char **argv)
 	int dns4addr_len;
 	struct sockaddr_storage dns6addr;
 	int dns6addr_len;
-        int forward_v6;
 #ifdef HAVE_SYSTEMD
 	int nb_fds;
 #endif
@@ -2434,7 +2466,6 @@ main(int argc, char **argv)
 	debug = 0;
 	netmask = 27;
 	pidfile = NULL;
-        forward_v6 = 0;
 	retval = 0;
 
 #ifdef WINDOWS32
@@ -2452,7 +2483,8 @@ main(int argc, char **argv)
 	srand(time(NULL));
 	fw_query_init();
 
-	while ((choice = getopt(argc, argv, "t:d:m:l:L:p:n:b:P:z:F:i:46vcsSfhDu")) != -1) {
+	while ((choice = getopt(argc, argv, "46vcsfhDuS:t:d:m:l:L:p:n:b:P:z:F:i:")) != -1) {
+
 		switch(choice) {
 		case '4':
 			addrfamily = AF_INET;
@@ -2524,7 +2556,7 @@ main(int argc, char **argv)
 			memset(optarg, 0, strlen(optarg));
 			break;
                 case 'S':
-                        forward_v6 = 1;
+                        display_ip6_buffer = optarg;
                         break;
 		case 'z':
 			context = optarg;
@@ -2553,10 +2585,28 @@ main(int argc, char **argv)
 	my_ip = inet_addr(argv[0]);
 
 	if (my_ip == INADDR_NONE) {
-		warnx("Bad IP address to use inside tunnel.");
+        	warnx("Bad IP address to use inside tunnel.");
 		usage();
 	}
 
+	
+	ip6_netmask_buffer = strchr(display_ip6_buffer, '/');
+	if (ip6_netmask_buffer) {
+		if (atoi(ip6_netmask_buffer+1) != ip6_netmask) {
+                     warnx("IPv6 address must be a 64-bit mask.");
+                     usage();
+		}
+		/* remove masklen */
+	        memcpy(display_ip6, display_ip6_buffer, strlen(display_ip6_buffer) - strlen(ip6_netmask_buffer)); 
+		display_ip6[strlen(display_ip6)+1] = '\0';
+        }
+
+        /* IPV6 address sanity check */
+        if (inet_pton(AF_INET6, display_ip6, &my_ip6) != 1) {
+		warnx("Bad IPv6 address to use inside tunnel.");
+		usage();
+        }
+
 	topdomain = strdup(argv[1]);
 	if (check_topdomain(topdomain, 1, &errormsg)) {
 		warnx("Invalid topdomain: %s", errormsg);
@@ -2685,7 +2735,7 @@ main(int argc, char **argv)
 	dns_fds.v4fd = -1;
 	dns_fds.v6fd = -1;
 
-	created_users = init_users(my_ip, netmask);
+	created_users = init_users(my_ip, netmask, my_ip6, ip6_netmask);
 
 	if ((tun_fd = open_tun(device)) == -1) {
 		/* nothing to clean up, just return */
@@ -2693,16 +2743,26 @@ main(int argc, char **argv)
 	}
 	if (!skipipconfig) {
 		const char *other_ip = users_get_first_ip();
-		if (tun_setip(argv[0], other_ip, netmask, forward_v6) != 0 || tun_setmtu(mtu) != 0) {
+		const char *display_other_ip6 = users_get_first_ip6();
+
+
+		if (tun_setip(argv[0], other_ip, netmask) != 0 || tun_setmtu(mtu) != 0) {
                         retval = 1;
 			free((void*) other_ip);
                         goto cleanup;
-			
+
 	        }
-		if ((mtu < 1280) && (forward_v6)) {
+
-                                warnx("Interface mtu of %d below the 1280 threshold needed for IPv6 tunneling.\n", mtu);         
+		if (tun_setip6(display_ip6, display_other_ip6, ip6_netmask) != 0 ) {
-                                warnx("Proceeding without IPv6 tunneling\n");         
+                        retval = 1;
-		} 
+                        goto cleanup;
+
+	        }
+
+		if ((mtu < 1280) && (sizeof(display_ip6)) != 0) {
+                                warnx("Interface mtu of %d below the 1280 threshold needed for IPv6 tunneling.\n", mtu);
+                                warnx("Proceeding without IPv6 tunneling\n");
+		}
 
 		free((void*) other_ip);
 	}

src/tun.c

@@ -35,6 +35,11 @@
 #include <netinet/ip.h>
 #endif
 
+#if defined FREEBSD || defined NETBSD 
+#include <sys/ioctl.h>
+#include <net/if_tun.h>
+#endif
+
 #ifndef IFCONFIGPATH
 #define IFCONFIGPATH "PATH=/sbin:/bin "
 #endif
@@ -82,6 +87,7 @@ static char if_name[250];
 #include <net/if.h>
 #include <linux/if_tun.h>
 
+
 int
 open_tun(const char *tun_device)
 {
@@ -452,7 +458,15 @@ open_tun(const char *tun_device)
 			snprintf(tun_name, sizeof(tun_name), "/dev/tun%d", i);
 
 			if ((tun_fd = open(tun_name, O_RDWR)) >= 0) {
-				fprintf(stderr, "Opened %s\n", tun_name);
+#if defined FREEBSD || defined NETBSD
+                                /* FreeBSD requires a packet header for
+                                 * IPv6 traffic
+                                 */
+                                if (ioctl(tun_fd, TUNSIFHEAD, &(int){1}) != 0) {
+		                   fprintf(stderr, "Not able to enable TUNSIFHEAD\n");
+                                   break; 
+                                }
+#endif /* LINUX */
 				snprintf(if_name, sizeof(if_name), "tun%d", i);
 				fd_set_close_on_exec(tun_fd);
 				return tun_fd;
@@ -530,9 +544,12 @@ read_tun(int tun_fd, char *buf, size_t len)
 static int
 tun_uses_header(void)
 {
-#if defined (FREEBSD) || defined (NETBSD)
+#if defined FREEBSD || defined NETBSD || defined OPENBSD
-	/* FreeBSD/NetBSD has no header */
+        /* To enable IPv6 in FreeBSD tunnels, tunnel
-	return 0;
+         * headers now enabled for that platform
+         */
+        return 1;
+
 #elif defined (DARWIN)
 	/* Darwin tun has no header, Darwin utun does */
 	return !strncmp(if_name, "utun", 4);
@@ -544,41 +561,82 @@ tun_uses_header(void)
 int
 write_tun(int tun_fd, char *data, size_t len)
 {
+
+        int ip_version = 0;
+ 
 	if (!tun_uses_header()) {
 		data += 4;
 		len -= 4;
 	} else {
-                int i = data[4] & 0xf0;
+
+                ip_version = get_ipversion(data[4]);
+
+                if (ip_version < 0) {
+                    return 1; /* Cannot read IP version number from packet */
+                }
+
 #ifdef LINUX
-		
+
-		if (i == 64) {
+		if (ip_version == 4) {
-		// Look at the fifth bype 
 		// Linux prefixes with 32 bits ethertype
 		// 0x0800 for IPv4, 0x86DD for IPv6
 	    	    data[0] = 0x00;
 		    data[1] = 0x00;
 		    data[2] = 0x08;
 		    data[3] = 0x00;
-	        } else { /* 96 for IPV6 */
+	        } else { /* IPV6 */
 	    	    data[0] = 0x00;
 		    data[1] = 0x00;
 		    data[2] = 0x86;
 		    data[3] = 0xDD;
-	       }	
+	       }
-#else /* OPENBSD and DARWIN(utun) */
+#elif defined (FREEBSD) || defined (OPENBSD)
+
 		// BSDs prefix with 32 bits address family
 		// AF_INET for IPv4, AF_INET6 for IPv6
-		if (i == 64) {
+		if (ip_version == 4) {
 	    	    data[0] = 0x00;
 		    data[1] = 0x00;
 		    data[2] = 0x00;
 		    data[3] = 0x02;
-	        } else { /* 96 for IPV6 */
+	        } else { /* IPV6 */
+	    	    data[0] = 0x00;
+		    data[1] = 0x00;
+		    data[2] = 0x00;
+		    data[3] = 0x1C;
+
+                }
+
+#elif defined NETBSD
+
+		// BSDs prefix with 32 bits address family
+		// AF_INET for IPv4, AF_INET6 for IPv6
+		if (ip_version == 4) {
+	    	    data[0] = 0x00;
+		    data[1] = 0x00;
+		    data[2] = 0x00;
+		    data[3] = 0x02;
+	        } else { /* IPV6 */
+	    	    data[0] = 0x00;
+		    data[1] = 0x00;
+		    data[2] = 0x00;
+		    data[3] = 0x18;
+
+                }
+#else /* DARWIN(utun) and all others */
+		
+		// BSDs prefix with 32 bits address family
+		// AF_INET for IPv4, AF_INET6 for IPv6
+		if (ip_version == 4) {
+	    	    data[0] = 0x00;
+		    data[1] = 0x00;
+		    data[2] = 0x00;
+		    data[3] = 0x02;
+	        } else { /* IPV6 */
 	    	    data[0] = 0x00;
 		    data[1] = 0x00;
 		    data[2] = 0x00;
 		    data[3] = 0x1E;
-
                 }
 #endif
 	}
@@ -610,14 +668,12 @@ read_tun(int tun_fd, char *buf, size_t len)
 #endif
 
 int
-tun_setip(const char *ip, const char *other_ip, int netbits, int forward_v6)
+tun_setip(const char *ip, const char *other_ip, int netbits)
 {
 	char cmdline[512];
-	char v6_cmdline[512];
 	int netmask;
 	struct in_addr net;
 	int i;
-	int v6_r;
 #ifndef LINUX
 	int r;
 #endif
@@ -650,20 +706,7 @@ tun_setip(const char *ip, const char *other_ip, int netbits, int forward_v6)
 # else
 	display_ip = ip;
 # endif
-	if (forward_v6) {
-                fprintf(stderr, "Setting IPv6 of %s to ::%s\n", if_name, ip);
 
-                snprintf(v6_cmdline, sizeof(cmdline),
-                        IFCONFIGPATH "ifconfig %s inet6 add ::%s/64",
-                        if_name,
-                        display_ip);
-
-	        v6_r = system(v6_cmdline);
-
-                if (v6_r != 0) {
-                    return v6_r;
-                } 
-        }
 	snprintf(cmdline, sizeof(cmdline),
 			IFCONFIGPATH "ifconfig %s %s %s netmask %s",
 			if_name,
@@ -722,14 +765,89 @@ tun_setip(const char *ip, const char *other_ip, int netbits, int forward_v6)
 	return system(cmdline);
 #endif
 
-        if (forward_v6) {
+}
-                snprintf(cmdline, sizeof(cmdline),
-                    IFCONFIGPATH "ifconfig %s inet6 add ::%s/64",
-                    if_name,
-                    ip);
 
-        fprintf(stderr, "Setting IP of %s to %s\n", if_name, ip);        
+int
+tun_setip6(char *display_ip6, const char *display_other_ip6, int netbits6)
+{
+	int v6_r;
+        struct in6_addr ip6;
+        char v6_cmdline[512];
+        if (inet_pton(AF_INET6, display_ip6, &ip6) < 1){
+            warnx("Error in IPv6 address");
         }
+
+#ifdef WINDOWS32
+        /*
+	DWORD status;
+	DWORD ipdata[3];
+	struct in_addr addr;
+	DWORD len;
+        */
+#endif
+
+	if (netbits6 > 0) {
+
+	   fprintf(stderr, "Setting IPv6 of %s to %s\n", if_name, display_ip6);
+
+#if defined LINUX
+                snprintf(v6_cmdline, sizeof(v6_cmdline),
+                        IFCONFIGPATH "ifconfig %s inet6 add %s/%d",
+                        if_name,
+                        display_ip6, netbits6);
+#else
+                snprintf(v6_cmdline, sizeof(v6_cmdline),
+                        IFCONFIGPATH "ifconfig %s inet6 %s/%d",
+                        if_name,
+                        display_ip6, netbits6);
+#endif
+
+	        v6_r = system(v6_cmdline);
+
+                if (v6_r != 0) {
+                    return v6_r;
+                } else {
+		    return 0;
+		}
+        }
+
+#ifdef WINDOWS32 /* WINDOWS32 */
+
+	/* Set device as connected */
+	fprintf(stderr, "Enabling interface '%s'\n", if_name);
+	status = 1;
+	r = DeviceIoControl(dev_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status,
+		sizeof(status), &status, sizeof(status), &len, NULL);
+	if (!r) {
+		fprintf(stderr, "Failed to enable interface\n");
+		return -1;
+	}
+
+	if (inet_aton(ip, &addr)) {
+		ipdata[0] = (DWORD) addr.s_addr;   /* local ip addr */
+		ipdata[1] = net.s_addr & ipdata[0]; /* network addr */
+		ipdata[2] = (DWORD) net.s_addr;    /* netmask */
+	} else {
+		return -1;
+	}
+
+	/* Tell ip/networkaddr/netmask to device for arp use */
+	r = DeviceIoControl(dev_handle, TAP_IOCTL_CONFIG_TUN, &ipdata,
+		sizeof(ipdata), &ipdata, sizeof(ipdata), &len, NULL);
+	if (!r) {
+		fprintf(stderr, "Failed to set interface in TUN mode\n");
+		return -1;
+	}
+
+	/* use netsh to set ip address */
+	fprintf(stderr, "Setting IP of interface '%s' to %s (can take a few seconds)...\n", if_name, ip);
+	snprintf(cmdline, sizeof(cmdline), "netsh interface ip set address \"%s\" static %s %s",
+		if_name, ip, inet_ntoa(net));
+	return system(cmdline);
+
+
+#endif
+  return 0;
 }
 
 int
@@ -757,3 +875,18 @@ tun_setmtu(const unsigned mtu)
 #endif
 }
 
+int get_ipversion(char first_byte)
+{
+
+    int v;
+
+    v = first_byte & 0xf0;
+
+    if (v == 64) {
+       return 4;
+    } else if (v == 96) {
+       return 6;
+    } else {
+       return -1;
+    }
+}

src/tun.h

@@ -22,7 +22,9 @@ int open_tun(const char *);
 void close_tun(int);
 int write_tun(int, char *, size_t);
 ssize_t read_tun(int, char *, size_t);
-int tun_setip(const char *, const char *, int, int);
+int tun_setip(const char *, const char *, int);
+int tun_setip6(char *, const char *, int);
 int tun_setmtu(const unsigned);
+int get_ipversion(char);
 
 #endif /* _TUN_H_ */

src/user.c

@@ -23,6 +23,7 @@
 #include <signal.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <math.h>
 
 #ifdef WINDOWS32
 #include <winsock2.h>
@@ -37,25 +38,26 @@
 struct tun_user *users;
 unsigned usercount;
 
-int init_users(in_addr_t my_ip, int netbits)
+int init_users(in_addr_t my_ip, int netbits, struct in6_addr my_ip6, int netbits6)
 {
 	int i;
+	int i6;
 	int skip = 0;
+	int skip6 = 0;
 	char newip[16];
-	char ip6Tmp[16];
-	char ip6Tmp2[18];
 
 	int maxusers;
 
 	in_addr_t netmask = 0;
 	struct in_addr net;
 	struct in_addr ipstart;
-	 
+        struct in6_addr ip6start;     
-	/* For IPv6, we take the IPv4 address and simply prepend ::
+        unsigned ip6_netmask[16]; 
-	 * and use a 64-bit mask. Reduces the need to parse
-	 * netmasks. 
-	 */
 
+	bool ip6_enabled;
+
+        ip6_enabled = isV6AddrSet(&my_ip6);
+ 
 	for (i = 0; i < netbits; i++) {
 		netmask = (netmask << 1) | 1;
 	}
@@ -63,17 +65,39 @@ int init_users(in_addr_t my_ip, int netbits)
 	net.s_addr = htonl(netmask);
 	ipstart.s_addr = my_ip & net.s_addr;
 
+        /* Covert IPv6 netbits to IPv6 netmask and work
+         * out the network address from my IP address. Start
+         * assigning IPv6 address from the network address + 1
+         */
+        if (ip6_enabled == true) {
+           for (i6 = 0; i6 < netbits6 / 8; i6++) {
+              ip6_netmask[i6] |= 0xFF;
+           }
+
+           ip6_netmask[netbits6 / 8] = pow(2, (netbits6 % 8 )) - 1;
+           ip6_netmask[netbits6 / 8] <<= (8-(netbits6 % 8)); 
+           
+           for (i6 = 0; i6 < 16; i6++) { 
+	       ip6start.s6_addr[i6] = my_ip6.s6_addr[i6] & ip6_netmask[i6];
+           } 
+        }
 	maxusers = (1 << (32-netbits)) - 3; /* 3: Net addr, broadcast addr, iodined addr */
 	usercount = MIN(maxusers, USERS);
 
 	users = calloc(usercount, sizeof(struct tun_user));
+        /* 
+         * IPv6 note: Current behavior is to populate the users structure
+         * with the IPv4 addresses that are expected to be used. 
+         * In the future with IPv6-only tunnel transport, we should not be
+         * populating a /64 (or whatever mask) in the users structure
+         * and should shift to an on-demand scheme. For now
+         * we expect dual-stack and pre-allocate IPv6 addresses into the
+         * users struct as we do with IPv4.
+         */
 	for (i = 0; i < usercount; i++) {
 		in_addr_t ip;
 		users[i].id = i;
 
-		memset(ip6Tmp,0,strlen(ip6Tmp)); 
-		memset(ip6Tmp2,0,strlen(ip6Tmp2)); 
-
 		snprintf(newip, sizeof(newip), "0.0.0.%d", i + skip + 1);
 
 		ip = ipstart.s_addr + inet_addr(newip);
@@ -82,15 +106,36 @@ int init_users(in_addr_t my_ip, int netbits)
 			skip++;
 			snprintf(newip, sizeof(newip), "0.0.0.%d", i + skip + 1);
 			ip = ipstart.s_addr + inet_addr(newip);
-
 			
 		}
 		users[i].tun_ip = ip;
 
-		inet_ntop(AF_INET, &ip, ip6Tmp, INET_ADDRSTRLEN);
+                if (ip6_enabled == true) {
-		snprintf(ip6Tmp2, sizeof(ip6Tmp2), "::%s", ip6Tmp);
+	           struct in6_addr temp_ip6;
-		inet_pton(AF_INET6, ip6Tmp2, &users[i].tun_ip6);
+                   /*
-		
+                    * start assigning host addresses from the network address + 1
+                    * unless that is my_ip, in which case, use the following address.
+                    */
+                   memcpy(temp_ip6.s6_addr, ip6start.s6_addr, sizeof(ip6start.s6_addr));
+                   temp_ip6.s6_addr[15] = ip6start.s6_addr[15] + skip + 1 + i;
+                  
+                   if (v6AddressesEqual(&temp_ip6, &my_ip6) == true &&
+                      skip6 == 0) {
+                         /* This IPv6 was taken by iodined */
+                         skip6++;
+
+                         /* 
+                          * We expect to start assigning addresses at the network address + 1 and
+                          * to not worry about assigning more than 254 host addresses. If we did, we have to 
+                          * iterate through lower order bytes of ip6. This plus a few other corner cases
+                          * is why we enourage/force/assume the user to specify a /64 V6 address
+                          */
+                   
+			 temp_ip6.s6_addr[15] = ip6start.s6_addr[15] + skip + 1 + i;
+
+	           }	
+                   memcpy(users[i].tun_ip6.s6_addr, temp_ip6.s6_addr, sizeof(temp_ip6.s6_addr));
+                }
 		net.s_addr = ip;
 		users[i].disabled = 0;
 		users[i].authenticated = 0;
@@ -110,6 +155,18 @@ const char *users_get_first_ip(void)
 	return strdup(inet_ntoa(ip));
 }
 
+const char *users_get_first_ip6(void)
+{
+	struct in6_addr ip6;
+        char display_ip6[INET6_ADDRSTRLEN];
+
+        memcpy(&ip6, &users[0].tun_ip6, sizeof(struct in6_addr));
+
+        inet_ntop(AF_INET6, &ip6, display_ip6, INET6_ADDRSTRLEN);
+        return strdup(display_ip6);
+}
+
+
 int find_user_by_ip6(struct in6_addr *v6Addr) 
 {
 	int i;
@@ -122,23 +179,23 @@ int find_user_by_ip6(struct in6_addr *v6Addr)
 			users[i].authenticated &&
 			!users[i].disabled &&
 			users[i].last_pkt + 60 > time(NULL) &&
-			(areV6AddressesEqual(v6Addr, &users[i].tun_ip6) == 0) ) {
+			v6AddressesEqual(v6Addr, &users[i].tun_ip6) == true) {
 			   return i;
-		}
+                }
 	}
 	return -1;
 }
 
-int areV6AddressesEqual(struct in6_addr *v6Struct1, struct in6_addr *v6Struct2)
+bool v6AddressesEqual(struct in6_addr *v6Struct1, struct in6_addr *v6Struct2)
 {
         int i;
     
 	for (i = 0; i < 16; i++) {
 		if (v6Struct1->s6_addr[i] != v6Struct2->s6_addr[i]) {
-		    return -1;
+		    return false;
 		}
         }
-	return 0;
+	return true;
 }
 
 

src/user.h

@@ -81,14 +81,15 @@ struct tun_user {
 
 extern struct tun_user *users;
 
-int init_users(in_addr_t, int);
+int init_users(in_addr_t, int, struct in6_addr, int);
 const char* users_get_first_ip(void);
+const char* users_get_first_ip6(void);
 int find_user_by_ip(uint32_t);
 int find_user_by_ip6(struct in6_addr *v6Addr);
 int all_users_waiting_to_send(void);
 int find_available_user(void);
 void user_switch_codec(int userid, const struct encoder *enc);
 void user_set_conn_type(int userid, enum connection c);
-int areV6AddressesEqual(struct in6_addr *, struct in6_addr *);
+bool v6AddressesEqual(struct in6_addr *, struct in6_addr *);
 
 #endif