Support dynamic binds with extra options (interface binds, specific addresses...)

2 files changed, 39 insertions, 7 deletions

diff --git a/src/fastd.c b/src/fastd.c
index 83d360b..da4268e 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -146,6 +146,21 @@ static inline void close_log(void) {
 }
 
 
+/** Return's an address's port (in network byte order) */
+static inline uint16_t get_bind_port(const fastd_bind_address_t *addr) {
+	switch (addr->addr.sa.sa_family) {
+	case AF_UNSPEC:
+	case AF_INET:
+		return addr->addr.in.sin_port;
+
+	case AF_INET6:
+		return addr->addr.in6.sin6_port;
+
+	default:
+		exit_bug("unsupported address family");
+	}
+}
+
 /** Initializes the configured sockets */
 static void init_sockets(void) {
 	ctx.socks = fastd_new_array(conf.n_bind_addrs, fastd_socket_t);
@@ -153,13 +168,18 @@ static void init_sockets(void) {
 	size_t i;
 	fastd_bind_address_t *addr = conf.bind_addrs;
 	for (i = 0; i < conf.n_bind_addrs; i++) {
-		ctx.socks[i] = (fastd_socket_t){ .fd = -2, .addr = addr };
+		if (get_bind_port(addr)) {
+			ctx.socks[i] = (fastd_socket_t){ .fd = -2, .addr = addr };
 
-		if (addr == conf.bind_addr_default_v4)
-			ctx.sock_default_v4 = &ctx.socks[i];
+			if (addr == conf.bind_addr_default_v4)
+				ctx.sock_default_v4 = &ctx.socks[i];
 
-		if (addr == conf.bind_addr_default_v6)
-			ctx.sock_default_v6 = &ctx.socks[i];
+			if (addr == conf.bind_addr_default_v6)
+				ctx.sock_default_v6 = &ctx.socks[i];
+		}
+		else {
+			ctx.socks[i] = (fastd_socket_t){ .fd = -1, .addr = NULL };
+		}
 
 		addr = addr->next;
 	}
diff --git a/src/socket.c b/src/socket.c
index 7d78b7f..e72ec94 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -199,6 +199,9 @@ bool fastd_socket_handle_binds(void) {
 		if (ctx.socks[i].fd >= 0)
 			continue;
 
+		if (!ctx.socks[i].addr)
+			continue;
+
 		ctx.socks[i].fd = bind_socket(ctx.socks[i].addr, ctx.socks[i].fd < -1);
 
 		if (ctx.socks[i].fd >= 0) {
@@ -226,11 +229,20 @@ bool fastd_socket_handle_binds(void) {
 	return true;
 }
 
-/** Opens a single unbound socket for the given address family */
+/** Opens a single socket bound to a random port for the given address family */
 fastd_socket_t * fastd_socket_open(fastd_peer_t *peer, int af) {
 	const fastd_bind_address_t any_address = { .addr.sa.sa_family = af };
 
-	int fd = bind_socket(&any_address, true);
+	const fastd_bind_address_t *bind_address;
+
+	if (af == AF_INET && conf.bind_addr_default_v4)
+		bind_address = conf.bind_addr_default_v4;
+	else if (af == AF_INET6 && conf.bind_addr_default_v6)
+		bind_address = conf.bind_addr_default_v6;
+	else
+		bind_address = &any_address;
+
+	int fd = bind_socket(bind_address, true);
 	if (fd < 0)
 		return NULL;