Handle not being able to bind to the configured port at startup.

[meshlink] / src / net_setup.c

diff --git a/src/net_setup.c b/src/net_setup.c
index 1b091db04034bd1a343390f508752d89de571b6a..b9cddeb00ccc2c7bd73dc69710ef7d148b63156c 100644 (file)
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -304,22 +304,7 @@ static bool load_node(meshlink_handle_t *mesh, const char *name, void *priv) {
 /*
   Add listening sockets.
 */
-static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bindto) {
-       char *port = mesh->myport;
-
-       if(address) {
-               char *space = strchr(address, ' ');
-
-               if(space) {
-                       *space++ = 0;
-                       port = space;
-               }
-
-               if(!strcmp(address, "*")) {
-                       *address = 0;
-               }
-       }
-
+static bool add_listen_sockets(meshlink_handle_t *mesh) {
        struct addrinfo *ai;
 
        struct addrinfo hint = {
@@ -329,9 +314,7 @@ static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bind
                .ai_flags = AI_PASSIVE,
        };
 
-       int err = getaddrinfo(address && *address ? address : NULL, port, &hint, &ai);
-
-       free(address);
+       int err = getaddrinfo(NULL, mesh->myport, &hint, &ai);
 
        if(err || !ai) {
                logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "getaddrinfo", err == EAI_SYSTEM ? strerror(err) : gai_strerror(err));
@@ -344,11 +327,12 @@ static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bind
                // Ignore duplicate addresses
                bool found = false;
 
-               for(int i = 0; i < mesh->listen_sockets; i++)
+               for(int i = 0; i < mesh->listen_sockets; i++) {
                        if(!memcmp(&mesh->listen_socket[i].sa, aip->ai_addr, aip->ai_addrlen)) {
                                found = true;
                                break;
                        }
+               }
 
                if(found) {
                        continue;
@@ -359,17 +343,47 @@ static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bind
                        return false;
                }
 
-               int tcp_fd = setup_listen_socket((sockaddr_t *) aip->ai_addr);
+               /* Try to bind to TCP */
+
+               int tcp_fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
 
-               if(tcp_fd < 0) {
+               if(tcp_fd == -1) {
                        continue;
                }
 
-               int udp_fd = setup_vpn_in_socket(mesh, (sockaddr_t *) aip->ai_addr);
+               if(bind(tcp_fd, aip->ai_addr, aip->ai_addrlen)) {
+                       closesocket(tcp_fd);
 
-               if(udp_fd < 0) {
-                       close(tcp_fd);
-                       continue;
+                       if(errno == EADDRINUSE) {
+                               /* If this port is in use for any address family, avoid it. */
+                               success = false;
+                               break;
+                       } else {
+                               continue;
+                       }
+               }
+
+               if(!setup_listen_socket(mesh, tcp_fd, aip->ai_family)) {
+                       closesocket(tcp_fd);
+                       success = false;
+                       break;
+               }
+
+               /* If TCP worked, then we require that UDP works as well. */
+
+               int udp_fd = socket(aip->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+
+               if(udp_fd == -1) {
+                       closesocket(tcp_fd);
+                       success = false;
+                       break;
+               }
+
+               if(bind(udp_fd, aip->ai_addr, aip->ai_addrlen) || !setup_vpn_in_socket(mesh, udp_fd, aip->ai_family)) {
+                       closesocket(tcp_fd);
+                       closesocket(udp_fd);
+                       success = false;
+                       break;
                }
 
                io_add(&mesh->loop, &mesh->listen_socket[mesh->listen_sockets].tcp, handle_new_meta_connection, &mesh->listen_socket[mesh->listen_sockets], tcp_fd, IO_READ);
@@ -381,7 +395,6 @@ static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bind
                        free(hostname);
                }
 
-               mesh->listen_socket[mesh->listen_sockets].bindto = bindto;
                memcpy(&mesh->listen_socket[mesh->listen_sockets].sa, aip->ai_addr, aip->ai_addrlen);
                memcpy(&mesh->listen_socket[mesh->listen_sockets].broadcast_sa, aip->ai_addr, aip->ai_addrlen);
 
@@ -398,6 +411,18 @@ static bool add_listen_address(meshlink_handle_t *mesh, char *address, bool bind
        }
 
        freeaddrinfo(ai);
+
+       if(!success) {
+               for(int i = 0; i < mesh->listen_sockets; i++) {
+                       io_del(&mesh->loop, &mesh->listen_socket[i].tcp);
+                       io_del(&mesh->loop, &mesh->listen_socket[i].udp);
+                       close(mesh->listen_socket[i].tcp.fd);
+                       close(mesh->listen_socket[i].udp.fd);
+               }
+
+               mesh->listen_sockets = 0;
+       }
+
        return success;
 }
 
@@ -423,17 +448,17 @@ bool setup_myself(meshlink_handle_t *mesh) {
 
        mesh->listen_sockets = 0;
 
-       if(!add_listen_address(mesh, NULL, NULL)) {
+       if(!add_listen_sockets(mesh)) {
                if(strcmp(mesh->myport, "0")) {
-                       logger(mesh, MESHLINK_INFO, "Could not bind to port %s, asking OS to choose one for us", mesh->myport);
-                       free(mesh->myport);
-                       mesh->myport = strdup("0");
+                       logger(mesh, MESHLINK_WARNING, "Could not bind to port %s, trying to find an alternative port", mesh->myport);
 
-                       if(!mesh->myport) {
-                               return false;
+                       if(!check_port(mesh)) {
+                               logger(mesh, MESHLINK_WARNING, "Could not bind to any port, trying to bind to port 0");
+                               free(mesh->myport);
+                               mesh->myport = xstrdup("0");
                        }
 
-                       if(!add_listen_address(mesh, NULL, NULL)) {
+                       if(!add_listen_sockets(mesh)) {
                                return false;
                        }
                } else {