Avoid ports that are in use by not all address families.

[meshlink] / src / meshlink.c

diff --git a/src/meshlink.c b/src/meshlink.c
index 07c518e0dd8c8c112aea2f85a84a756947998005..c6b14b8f043c1b0bdb4c38b6db8aa687651659b7 100644 (file)
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -537,26 +537,52 @@ static bool try_bind(int port) {
                return false;
        }
 
-       //while(ai) {
+       bool success = false;
+
        for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
-               int fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+               /* Try to bind to TCP. */
 
-               if(!fd) {
-                       freeaddrinfo(ai);
-                       return false;
+               int tcp_fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+
+               if(tcp_fd == -1) {
+                       continue;
                }
 
-               int result = bind(fd, aip->ai_addr, aip->ai_addrlen);
-               closesocket(fd);
+               int result = bind(tcp_fd, aip->ai_addr, aip->ai_addrlen);
+               closesocket(tcp_fd);
 
                if(result) {
-                       freeaddrinfo(ai);
-                       return false;
+                       if(errno == EADDRINUSE) {
+                               /* If this port is in use for any address family, avoid it. */
+                               success = false;
+                               break;
+                       } else {
+                               continue;
+                       }
                }
+
+               /* 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) {
+                       success = false;
+                       break;
+               }
+
+               result = bind(udp_fd, aip->ai_addr, aip->ai_addrlen);
+               closesocket(udp_fd);
+
+               if(result) {
+                       success = false;
+                       break;
+               }
+
+               success = true;
        }
 
        freeaddrinfo(ai);
-       return true;
+       return success;
 }
 
 static int check_port(meshlink_handle_t *mesh) {
@@ -1558,9 +1584,6 @@ static void *meshlink_main_loop(void *arg) {
 }
 
 bool meshlink_start(meshlink_handle_t *mesh) {
-       assert(mesh->self);
-       assert(mesh->private_key);
-
        if(!mesh) {
                meshlink_errno = MESHLINK_EINVAL;
                return false;
@@ -1570,6 +1593,8 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 
        pthread_mutex_lock(&mesh->mutex);
 
+       assert(mesh->self);
+       assert(mesh->private_key);
        assert(mesh->self->ecdsa);
        assert(!memcmp((uint8_t *)mesh->self->ecdsa + 64, (uint8_t *)mesh->private_key + 64, 32));
 
@@ -2279,7 +2304,7 @@ bool meshlink_sign(meshlink_handle_t *mesh, const void *data, size_t len, void *
 }
 
 bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len, const void *signature, size_t siglen) {
-       if(!mesh || !data || !len || !signature) {
+       if(!mesh || !source || !data || !len || !signature) {
                meshlink_errno = MESHLINK_EINVAL;
                return false;
        }