Initial server receiving

firewall-server/server.c

@@ -1,6 +1,76 @@
+#include <sys/socket.h>
+#include <netdb.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
 
-int main (int argc, char **argv) {
-    // Server to be written
+int open_socket(const char *ip, const char *port, int *res_sd) {
+    // get address info
+
+    struct addrinfo addr_spec;
+    struct addrinfo *addrinfo_res;
+
+    memset(&addr_spec, 0, sizeof(addr_spec));
+    addr_spec.ai_family = AF_UNSPEC;
+    addr_spec.ai_socktype = SOCK_STREAM;
+
+    int addrinfo_status = getaddrinfo(ip, port, &addr_spec, &addrinfo_res);
+    if (addrinfo_status != 0) {
+        fprintf(stderr, "get address info: %s\n", gai_strerror(addrinfo_status));
+        return 1;
+    }
+
+    int sd = socket(addrinfo_res->ai_family, addrinfo_res->ai_socktype, addrinfo_res->ai_protocol);
+
+    if (sd == -1) {
+        perror("failed to open socket");
+        return 1;
+    }
+
+    if (bind(sd, addrinfo_res->ai_addr, addrinfo_res->ai_addrlen) == -1) {
+        perror("failed to bind to port");
+        return 1;
+    }
+
+    if (listen(sd, 5)) {
+        perror("failed to start listening for connections");
+        return 1;
+    }
+
+    *res_sd = sd;
+    freeaddrinfo(addrinfo_res);
     return 0;
 }
+
+int main (int argc, char **argv) {
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s PORT\n", argv[0]);
+        return 1;
+    }
+    char *port_str = argv[1];
+
+    int sd;
+    if (open_socket("127.0.0.1", port_str, &sd) != 0) {
+        return 1;
+    }
+
+    int new_sd = accept(sd, NULL, NULL);
+    if (new_sd == -1) {
+        perror("failed to accept new connection");
+        return 1;
+    }
+
+    char *dat = (char *) malloc(sizeof(char) * 128);
+
+    int num_bytes = recv(new_sd, dat, 128, 0);
+    do {
+        if (num_bytes == -1) {
+            perror("failed to receive from remote host");
+            return 1;
+        }
+        printf("%s", dat);
+    } while ((num_bytes = recv(new_sd, dat, 128, 0)) != 0);
+    
+    return 0;
+}