Add local address information to edges.

In addition to the remote address, each edge now stores the local address from
the point of view of the "from" node. This information is then made available
to other nodes through a backwards-compatible extension to ADD_EDGE messages.

This information can be used in future code to improve packet routing.

src/edge.c

@@ -110,11 +110,13 @@ bool dump_edges(connection_t *c) {
 	for splay_each(node_t, n, node_tree) {
 		for splay_each(edge_t, e, n->edge_tree) {
 			char *address = sockaddr2hostname(&e->address);
-			send_request(c, "%d %d %s %s %s %x %d",
+			char* local_address = sockaddr2hostname(&e->local_address);
+			send_request(c, "%d %d %s %s %s %s %x %d",
 					CONTROL, REQ_DUMP_EDGES,
 					e->from->name, e->to->name, address,
-					e->options, e->weight);
+					local_address, e->options, e->weight);
 			free(address);
+			free(local_address);
 		}
 	}
 

src/edge.h

@@ -30,6 +30,7 @@ typedef struct edge_t {
 	struct node_t *from;
 	struct node_t *to;
 	sockaddr_t address;
+	sockaddr_t local_address;
 
 	uint32_t options;                       /* options turned on for this edge */
 	int weight;                             /* weight of this edge */

src/protocol_auth.c

@@ -822,6 +822,16 @@ bool ack_h(connection_t *c, const char *request) {
 	sockaddr2str(&c->address, &hisaddress, NULL);
 	c->edge->address = str2sockaddr(hisaddress, hisport);
 	free(hisaddress);
+	sockaddr_t local_sa;
+	socklen_t local_salen = sizeof local_sa;
+	if (getsockname(c->socket, &local_sa.sa, &local_salen) < 0)
+		logger(DEBUG_ALWAYS, LOG_WARNING, "Could not get local socket address for connection with %s", c->name);
+	else {
+		char *local_address;
+		sockaddr2str(&local_sa, &local_address, NULL);
+		c->edge->local_address = str2sockaddr(local_address, myport);
+		free(local_address);
+	}
 	c->edge->weight = (weight + c->estimated_weight) / 2;
 	c->edge->connection = c;
 	c->edge->options = c->options;

src/protocol_edge.c

@@ -37,14 +37,19 @@
 bool send_add_edge(connection_t *c, const edge_t *e) {
 	bool x;
 	char *address, *port;
+	char *local_address, *local_port;
 
 	sockaddr2str(&e->address, &address, &port);
+	sockaddr2str(&e->local_address, &local_address, &local_port);
 
-	x = send_request(c, "%d %x %s %s %s %s %x %d", ADD_EDGE, rand(),
+	x = send_request(c, "%d %x %s %s %s %s %x %d %s %s", ADD_EDGE, rand(),
 					 e->from->name, e->to->name, address, port,
-					 e->options, e->weight);
+					 e->options, e->weight, local_address, local_port);
+
 	free(address);
 	free(port);
+	free(local_address);
+	free(local_port);
 
 	return x;
 }
@@ -56,12 +61,15 @@ bool add_edge_h(connection_t *c, const char *request) {
 	char to_name[MAX_STRING_SIZE];
 	char to_address[MAX_STRING_SIZE];
 	char to_port[MAX_STRING_SIZE];
-	sockaddr_t address;
+	char address_local[MAX_STRING_SIZE] = "unknown";
+	char port_local[MAX_STRING_SIZE] = "unknown";
+	sockaddr_t address, local_address;
 	uint32_t options;
 	int weight;
 
-	if(sscanf(request, "%*d %*x "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING" %x %d",
-			  from_name, to_name, to_address, to_port, &options, &weight) != 6) {
+	int parameter_count = sscanf(request, "%*d %*x "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING" %x %d "MAX_STRING" "MAX_STRING,
+			                      from_name, to_name, to_address, to_port, &options, &weight, address_local, port_local);
+	if (parameter_count != 6 && parameter_count != 8) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ADD_EDGE", c->name,
 			   c->hostname);
 		return false;
@@ -109,13 +117,14 @@ bool add_edge_h(connection_t *c, const char *request) {
 	/* Convert addresses */
 
 	address = str2sockaddr(to_address, to_port);
+	local_address = str2sockaddr(address_local, port_local);
 
 	/* Check if edge already exists */
 
 	e = lookup_edge(from, to);
 
 	if(e) {
-		if(e->weight != weight || e->options != options || sockaddrcmp(&e->address, &address)) {
+		if(e->weight != weight || e->options != options || sockaddrcmp(&e->address, &address) || sockaddrcmp(&e->local_address, &local_address)) {
 			if(from == myself) {
 				logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) for ourself which does not match existing entry",
 						   "ADD_EDGE", c->name, c->hostname);
@@ -145,6 +154,7 @@ bool add_edge_h(connection_t *c, const char *request) {
 	e->from = from;
 	e->to = to;
 	e->address = address;
+	e->local_address = local_address;
 	e->options = options;
 	e->weight = weight;
 	edge_add(e);

src/tincctl.c

@@ -985,6 +985,8 @@ static int cmd_dump(int argc, char *argv[]) {
 		char subnet[4096];
 		char host[4096];
 		char port[4096];
+		char local_host[4096];
+		char local_port[4096];
 		char via[4096];
 		char nexthop[4096];
 		int cipher, digest, maclength, compression, distance, socket, weight;
@@ -1025,8 +1027,8 @@ static int cmd_dump(int argc, char *argv[]) {
 			} break;
 
 			case REQ_DUMP_EDGES: {
-				int n = sscanf(line, "%*d %*d %s %s %s port %s %x %d", from, to, host, port, &options, &weight);
-				if(n != 6) {
+				int n = sscanf(line, "%*d %*d %s %s %s port %s %s port %s %x %d", from, to, host, port, local_host, local_port, &options, &weight);
+				if(n != 8) {
 					fprintf(stderr, "Unable to parse edge dump from tincd.\n");
 					return 1;
 				}
@@ -1038,7 +1040,7 @@ static int cmd_dump(int argc, char *argv[]) {
 					else if(do_graph == 2)
 						printf(" %s -> %s [w = %f, weight = %f];\n", node1, node2, w, w);
 				} else {
-					printf("%s to %s at %s port %s options %x weight %d\n", from, to, host, port, options, weight);
+					printf("%s to %s at %s port %s local %s port %s options %x weight %d\n", from, to, host, port, local_host, local_port, options, weight);
 				}
 			} break;