move dirs

code/C/AF_INET_sockets/echo_server.c

@@ -0,0 +1,48 @@
+/* https://rsdn.org/article/unix/sockets.xml */
+
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+int main()
+{
+    int sock, listener;
+    struct sockaddr_in addr;
+    char buf[1024];
+    int bytes_read;
+
+    listener = socket(AF_INET, SOCK_STREAM, 0);
+    if (listener < 0) {
+        perror("socket");
+        exit(1);
+    }
+
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(3425);
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);
+    if (bind(listener, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        perror("bind");
+        exit(2);
+    }
+
+    listen(listener, 1);
+
+    while(1) {
+        sock = accept(listener, NULL, NULL);
+        if (sock < 0) {
+            perror("accept");
+            exit(3);
+        }
+
+        while(1) {
+            bytes_read = recv(sock, buf, 1024, 0);
+            if (bytes_read <= 0) break;
+            send(sock, buf, bytes_read, 0);
+        }
+
+        close(sock);
+    }
+
+    return 0;
+}