tcp-ip-sockets-in-c/ch2/TCPEchoServer4.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "Practical.h"
#include "TCPServerUtility.h"

static const int MAXPENDING = 5;

int main(int argc, char **argv) {
    if (argc != 2) {
        DieWithUserMessage("Parameter(s)", "<Server Port>");
    }

    const in_port_t server_port = atoi(argv[1]);

    const int server_sock = socket(AF_INET, SOCK_STREAM, proto_get_num("tcp"));
    if (server_sock < 0) {
        DieWithSystemMessage("socket() failed");
    }

    struct sockaddr_in server_addr = {
        .sin_family = AF_INET,
        .sin_addr = {
            .s_addr = htonl(INADDR_ANY),
        },
        .sin_port = htons(server_port)
    };

    int ret_val = bind(
        server_sock,
        (struct sockaddr *) &server_addr,
        sizeof(server_addr)
    );
    if (ret_val < 0) {
        DieWithSystemMessage("bind() failed");
    }

    ret_val = listen(server_sock, MAXPENDING);
    if (ret_val < 0) {
        DieWithSystemMessage("listen() failed");
    } else {
        char server_name[INET_ADDRSTRLEN];
        const char *ntop_res = inet_ntop(
            AF_INET,
            &server_addr.sin_addr.s_addr,
            server_name,
            sizeof(server_name)
        );
        if (ntop_res != NULL) {
            printf("Listening on %s/%d...\n", server_name, server_port);
        } else {
            puts("Unable to get server address");
        }
    }

    while (1) {
        struct sockaddr_in client_addr;
        socklen_t client_addr_len = sizeof(client_addr);

        int client_sock = accept(
            server_sock,
            (struct sockaddr *) &client_addr,
            &client_addr_len
        );
        if (client_sock < 0) {
            DieWithSystemMessage("accept() failed");
        }

        char client_name[INET_ADDRSTRLEN];
        const char *ntop_res = inet_ntop(
            AF_INET,
            &client_addr.sin_addr.s_addr,
            client_name,
            sizeof(client_name)
        );
        if (ntop_res != NULL) {
            printf(
                "Handling client %s/%d\n",
                client_name,
                ntohs(client_addr.sin_port)
            );
        } else {
            puts("Unable to get client address");
        }

        HandleTCPClient(client_sock);
    }

    return 0;
}