Add support for ephemeral ports (#136)

Author: alastairpatrick

src/bsd.c

@@ -1,5 +1,5 @@
 /*
- * Authored by Alex Hultman, 2018-2019.
+ * Authored by Alex Hultman, 2018-2021.
  * Intellectual property of third-party.
 
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -107,15 +107,27 @@ void internal_finalize_bsd_addr(struct bsd_addr_t *addr) {
     if (addr->mem.ss_family == AF_INET6) {
         addr->ip = (char *) &((struct sockaddr_in6 *) addr)->sin6_addr;
         addr->ip_length = sizeof(struct in6_addr);
+        addr->port = ntohs(((struct sockaddr_in6 *) addr)->sin6_port);
     } else if (addr->mem.ss_family == AF_INET) {
         addr->ip = (char *) &((struct sockaddr_in *) addr)->sin_addr;
         addr->ip_length = sizeof(struct in_addr);
+        addr->port = ntohs(((struct sockaddr_in *) addr)->sin_port);
     } else {
         addr->ip_length = 0;
+        addr->port = -1;
     }
 }
 
-int bsd_socket_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr) {
+int bsd_local_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr) {
+    addr->len = sizeof(addr->mem);
+    if (getsockname(fd, (struct sockaddr *) &addr->mem, &addr->len)) {
+        return -1;
+    }
+    internal_finalize_bsd_addr(addr);
+    return 0;
+}
+
+int bsd_remote_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr) {
     addr->len = sizeof(addr->mem);
     if (getpeername(fd, (struct sockaddr *) &addr->mem, &addr->len)) {
         return -1;
@@ -132,6 +144,10 @@ int bsd_addr_get_ip_length(struct bsd_addr_t *addr) {
     return addr->ip_length;
 }
 
+int bsd_addr_get_port(struct bsd_addr_t *addr) {
+    return addr->port;
+}
+
 // called by dispatch_ready_poll
 LIBUS_SOCKET_DESCRIPTOR bsd_accept_socket(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr) {
     LIBUS_SOCKET_DESCRIPTOR accepted_fd;
@@ -228,17 +244,18 @@ LIBUS_SOCKET_DESCRIPTOR bsd_create_listen_socket(const char *host, int port, int
         return LIBUS_SOCKET_ERROR;
     }
 
-    /* Always enable SO_REUSEPORT and SO_REUSEADDR _unless_ options specify otherwise */
+    if (port != 0) {
+        /* Otherwise, always enable SO_REUSEPORT and SO_REUSEADDR _unless_ options specify otherwise */
 #if /*defined(__linux) &&*/ defined(SO_REUSEPORT)
-    if (!(options & LIBUS_LISTEN_EXCLUSIVE_PORT)) {
-        int optval = 1;
-        setsockopt(listenFd, SOL_SOCKET, SO_REUSEPORT, &optval, sizeof(optval));
-    }
+        if (!(options & LIBUS_LISTEN_EXCLUSIVE_PORT)) {
+            int optval = 1;
+            setsockopt(listenFd, SOL_SOCKET, SO_REUSEPORT, &optval, sizeof(optval));
+        }
 #endif
-
-    int enabled = 1;
-    setsockopt(listenFd, SOL_SOCKET, SO_REUSEADDR, (SETSOCKOPT_PTR_TYPE) &enabled, sizeof(enabled));
-
+        int enabled = 1;
+        setsockopt(listenFd, SOL_SOCKET, SO_REUSEADDR, (SETSOCKOPT_PTR_TYPE) &enabled, sizeof(enabled));
+    }
+    
 #ifdef IPV6_V6ONLY
     int disabled = 0;
     setsockopt(listenFd, IPPROTO_IPV6, IPV6_V6ONLY, (SETSOCKOPT_PTR_TYPE) &disabled, sizeof(disabled));

src/internal/networking/bsd.h

@@ -45,6 +45,7 @@ struct bsd_addr_t {
     socklen_t len;
     char *ip;
     int ip_length;
+    int port;
 };
 
 LIBUS_SOCKET_DESCRIPTOR apple_no_sigpipe(LIBUS_SOCKET_DESCRIPTOR fd);
@@ -59,12 +60,14 @@ void bsd_shutdown_socket_read(LIBUS_SOCKET_DESCRIPTOR fd);
 
 void internal_finalize_bsd_addr(struct bsd_addr_t *addr);
 
-int bsd_socket_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr);
+int bsd_local_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr);
+int bsd_remote_addr(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr);
 
 char *bsd_addr_get_ip(struct bsd_addr_t *addr);
-
 int bsd_addr_get_ip_length(struct bsd_addr_t *addr);
 
+int bsd_addr_get_port(struct bsd_addr_t *addr);
+
 // called by dispatch_ready_poll
 LIBUS_SOCKET_DESCRIPTOR bsd_accept_socket(LIBUS_SOCKET_DESCRIPTOR fd, struct bsd_addr_t *addr);
 

src/libusockets.h

@@ -251,6 +251,9 @@ WIN32_EXPORT int us_socket_is_closed(int ssl, struct us_socket_t *s);
 /* Immediately closes the socket */
 WIN32_EXPORT struct us_socket_t *us_socket_close(int ssl, struct us_socket_t *s, int code, void *reason);
 
+/* Returns local port or -1 on failure. */
+WIN32_EXPORT int us_socket_local_port(int ssl, struct us_socket_t *s);
+
 /* Copy remote (IP) address of socket, or fail with zero length. */
 WIN32_EXPORT void us_socket_remote_address(int ssl, struct us_socket_t *s, char *buf, int *length);
 

src/socket.c

@@ -22,14 +22,23 @@
 
 /* Shared with SSL */
 
+int us_socket_local_port(int ssl, struct us_socket_t *s) {
+    struct bsd_addr_t addr;
+    if (bsd_local_addr(us_poll_fd(&s->p), &addr)) {
+        return -1;
+    } else {
+        return bsd_addr_get_port(&addr);
+    }
+}
+
 void us_socket_shutdown_read(int ssl, struct us_socket_t *s) {
     /* This syscall is idempotent so no extra check is needed */
     bsd_shutdown_socket_read(us_poll_fd((struct us_poll_t *) s));
 }
 
 void us_socket_remote_address(int ssl, struct us_socket_t *s, char *buf, int *length) {
     struct bsd_addr_t addr;
-    if (bsd_socket_addr(us_poll_fd(&s->p), &addr) || *length < bsd_addr_get_ip_length(&addr)) {
+    if (bsd_remote_addr(us_poll_fd(&s->p), &addr) || *length < bsd_addr_get_ip_length(&addr)) {
         *length = 0;
     } else {
         *length = bsd_addr_get_ip_length(&addr);