--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/server/util/socket.c Sun Feb 15 12:24:38 2026 +0100
@@ -0,0 +1,104 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2026 Olaf Wintermann. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "socket.h"
+
+#include <unistd.h>
+#include <sys/fcntl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+int util_server_socket_local(short *port) {
+ int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
+ if(socket_fd < 0) {
+ return -1;
+ }
+
+ short socket_port = 0;
+ if(port) {
+ socket_port = *port;
+ }
+
+ struct sockaddr_in addr;
+ addr.sin_family = AF_INET;
+ addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ addr.sin_port = htons(socket_port);
+
+ if(bind(socket_fd, (struct sockaddr*)&addr, sizeof(addr))) {
+ close(socket_fd);
+ return -1;
+ }
+
+ socklen_t len = sizeof(addr);
+ if(getsockname(socket_fd, (struct sockaddr *)&addr, &len) < 0) {
+ close(socket_fd);
+ return -1;
+ }
+
+ if(port) {
+ *port = ntohs(addr.sin_port);
+ }
+
+ return socket_fd;
+}
+
+int util_socket_connect_local(short port) {
+ int fd = socket(AF_INET, SOCK_STREAM, 0);
+ if(fd < 0) {
+ return -1;
+ }
+
+ struct sockaddr_in addr;
+ addr.sin_family = AF_INET;
+ addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ addr.sin_port = htons(port);
+
+ if(connect(fd, (struct sockaddr*)&addr, sizeof(addr))) {
+ close(fd);
+ return -1;
+ }
+
+ return fd;
+}
+
+int util_socket_setnonblock(int fd, int nonblock) {
+ int flags;
+ if ((flags = fcntl(fd, F_GETFL, 0)) == -1) {
+ flags = 0;
+ }
+ if(nonblock) {
+ flags |= O_NONBLOCK;
+ } else {
+ flags &= ~O_NONBLOCK;
+ }
+ if (fcntl(fd, F_SETFL, flags) != 0) {
+ return 1;
+ }
+ return 0;
+}