Updated README with IPv6 details and fixed a bug with IPV6 only

enabled on one end of the tunnelx

README.md

@@ -123,7 +123,7 @@ end of the tunnel. In this case, `ping 192.168.99.1` from the iodine client, and
 ### MISC. INFO
 
 #### IPv6
-The data inside the tunnel is IPv4 only.
+The data inside the tunnel may be IPv4 or IPv6.
 
 The server listens to both IPv4 and IPv6 for incoming requests by default.
 Use options `-4` or `-6` to only listen on one protocol. Raw mode will be
@@ -141,6 +141,14 @@ to your DNS setup. Extending the example above would look like this:
 	t1ns		IN	A	10.15.213.99
 	t1ns		IN	AAAA	2001:db8::1001:99
 
+On the server, specify -S followed by an IPv6 address that will be the server end
+of the IPv6 pool to allocate to clients. The server only supports a /64 subnet 
+mask, which is assumed and can be omitted. The first 64 bits are the network from
+which IPv6 addresses are allocated from.
+
+The client will automatically check for IPv6 capability on the server and 
+assign the allocated address to its tunnel interface. No flags are needed.
+
 #### Routing
 It is possible to route all traffic through the DNS tunnel. To do this, first
 add a host route to the nameserver used by iodine over the wired/wireless

src/client.c

@@ -2440,11 +2440,12 @@ int
 handshake_check_v6(int dns_fd)
 {
 	char in[4096];
-	char server6[1024];
+	char server6[INET6_ADDRSTRLEN];
-	char client6[1024];
+	char client6[INET6_ADDRSTRLEN];
 	int i;
 	int read;
 	int netmask6 = 0;
+        int length_recieved;
 
 	fprintf(stderr, "Autoprobing server IPV6 tunnel support\n");
 
@@ -2468,10 +2469,13 @@ handshake_check_v6(int dns_fd)
 		         fprintf(stderr, "Server tunnel IPv6 is %s\n", server6);
 			 fprintf(stderr, "Local tunnel IPv6 is %s\n", client6);
 
+                         length_recieved = strlen(client6);
+                         if (length_recieved  > 2) {
 			     if (tun_setip6(client6, server6, netmask6) == 0) {
 
                                  use_v6 = true;
 				 return 0;
+
 		             } else {
 			         errx(4, "Failed to set IPv6 tunnel address");
 			     }
@@ -2479,6 +2483,7 @@ handshake_check_v6(int dns_fd)
 			     fprintf(stderr, "Received bad IPv6 tunnel handshake\n");
 			 }
                      }
+		 }
 
 		 fprintf(stderr, "Retrying IPv6 tunnel handshake...\n");
 	}

src/iodined.c

@@ -90,8 +90,8 @@ static int my_mtu;
 static in_addr_t my_ip;
 
 char display_ip6[INET6_ADDRSTRLEN];
-char *display_ip6_buffer;
+char *display_ip6_buffer = NULL;
-char *ip6_netmask_buffer;
+char *ip6_netmask_buffer = NULL;
 
 static struct in6_addr my_ip6;
 static int netmask;
@@ -2590,8 +2590,11 @@ main(int argc, char **argv)
 	}
 
 	
+	if (display_ip6_buffer != NULL) {
+
 	    ip6_netmask_buffer = strchr(display_ip6_buffer, '/');
-	if (ip6_netmask_buffer) {
+
+	    if (ip6_netmask_buffer != NULL) {
 		   if (atoi(ip6_netmask_buffer+1) != ip6_netmask) {
                        warnx("IPv6 address must be a 64-bit mask.");
                        usage();
@@ -2606,6 +2609,7 @@ main(int argc, char **argv)
 		warnx("Bad IPv6 address to use inside tunnel.");
 		usage();
             }
+        }
 
 	topdomain = strdup(argv[1]);
 	if (check_topdomain(topdomain, 1, &errormsg)) {
@@ -2753,10 +2757,11 @@ main(int argc, char **argv)
 
 	        }
 
+		if (display_ip6_buffer != NULL) {
 		    if (tun_setip6(display_ip6, display_other_ip6, ip6_netmask) != 0 ) {
                           retval = 1;
                           goto cleanup;
-
+                    }
 	        }
 
 		if ((mtu < 1280) && (sizeof(display_ip6)) != 0) {