Socket Example (Echo Server/Client)

Details

Application flow

• Check command line options if they correct daemonize.
• If required create SSL sessions.
• Create one server and 2 client sockets.
• Bind the server socket.
• Connect the clients to the server.
• Start the server thread.
• Start client threads.
• Write the client name to the server via the client socket.
• Echo back to the client and sleep the server thread for 1 second.
• Sleep the main thread for 5 seconds allowing exit.

Annotation

See doxygen/examples/socket.c for annotated source code.

Code

#ifdef __WIN32
#include <winsock2.h>
#include <stdint.h>
#else
#include <fcntl.h>
#endif

#include <string.h>
#include <stdio.h>

#include <openssl/ssl.h>
#include <dtsapp.h>

void accept_func(struct fwsocket *sock, void *data) {
}

void server_func(struct fwsocket *sock, void *data) {
    char buff[128];
    union sockstruct addr;

    if (socketread_d(sock, &buff, 128, &addr) > 0) {
        socketwrite_d(sock, &buff, strlen(buff) + 1, &addr);
        printf("[S] %s %i\n", buff, sock->sock);
        sleep(1);
    }
}

void client_func(struct fwsocket *sock, void *data) {
    char buff[128];

    if (socketread(sock, &buff, 128) > 0) {
        socketwrite(sock, &buff, strlen(buff) + 1);
        printf("[C] %s %i\n", buff, sock->sock);
    }
}

void socktest(const char *ipaddr, int tcp, int ssl) {
    struct fwsocket *serv, *client, *client2;
    void *ssl_c = NULL, *ssl_s = NULL, *ssl_c2 = NULL;
    char *buff = "client 1";
    char *buff2 = "client 2";
    int cnt;

    if (ssl && tcp) {
        ssl_s = sslv3_init("certs/cacert.pem", "certs/server-cert.pem", "certs/server-key.pem", SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE);
        ssl_c = sslv3_init("certs/cacert.pem", "certs/client-cert.pem", "certs/client-key.pem", SSL_VERIFY_NONE);
        ssl_c2 = sslv3_init("certs/cacert.pem", "certs/client-cert.pem", "certs/client-key.pem", SSL_VERIFY_NONE);
    } else if (ssl) {
        ssl_s = dtlsv1_init("certs/cacert.pem", "certs/server-cert.pem", "certs/server-key.pem", SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE);
        ssl_c = dtlsv1_init("certs/cacert.pem", "certs/client-cert.pem", "certs/client-key.pem", SSL_VERIFY_NONE);
        ssl_c2 = dtlsv1_init("certs/cacert.pem", "certs/client-cert.pem", "certs/client-key.pem", SSL_VERIFY_NONE);
    }

    if (tcp) {
        serv = tcpbind(ipaddr, "1111", ssl_s, 10);
        client = tcpconnect(ipaddr, "1111", ssl_c);
        client2 = tcpconnect(ipaddr, "1111", ssl_c2);
    } else {
        serv = udpbind(ipaddr, "1111", ssl_s);
        client = udpconnect(ipaddr, "1111", ssl_c);
        client2 = udpconnect(ipaddr, "1111", ssl_c2);
    }

    if (serv && client && client2) {
        socketserver(serv, server_func, accept_func, NULL, NULL);
        socketclient(client, NULL, client_func, NULL);
        socketclient(client2, NULL, client_func, NULL);

        socketwrite(client, buff, strlen(buff)+1);
        socketwrite(client2, buff2, strlen(buff2)+1);

        sleep(5);
    } else {
        printf("ERROR\n");
    }

    close_socket(client);
    close_socket(client2);
    close_socket(serv);
}

#ifndef __WIN32
void unixsocktest(const char *socket, int protocol) {
    char *buff = "client 1";
    char *buff2 = "client 2";
    struct fwsocket *client, *client2, *server;

    server = unixsocket_server(socket, protocol, S_IXUSR | S_IWGRP | S_IRGRP | S_IXGRP | S_IWOTH | S_IROTH | S_IXOTH, server_func, NULL);
    sleep(1); /*wait for socket*/
    client = unixsocket_client(socket, protocol, client_func, NULL);
    client2 = unixsocket_client(socket, protocol, client_func, NULL);

    socketwrite_d(client, buff, strlen(buff)+1, NULL);
    socketwrite_d(client2, buff2, strlen(buff2)+1, NULL);

    sleep(5);

    close_socket(client);
    close_socket(client2);
    close_socket(server);
}
#endif

FRAMEWORK_MAIN("Socket Client/Server Echo (TCP/TLS/UDP/DTLS)", "Gregory Hinton Nietsky", "gregory@distrotech.co.za",
        "http://www.distrotech.co.za", 2013, "/var/run/sockettest", FRAMEWORK_FLAG_DAEMONLOCK, NULL) {

    if (argc < 3) {
#ifndef __WIN32
        printf("Requires arguments %s [tcp|tls|udp|dtls|unix_d|unix_s] [ipaddr|socket]\n", argv[0]);
#else
        printf("Requires arguments %s [tcp|tls|udp|dtls] ipaddr\n", argv[0]);
#endif
        return (-1);
    }

    daemonize();
    if (!strcmp(argv[1], "udp")) {
        socktest(argv[2], 0, 0);
    } else if (!strcmp(argv[1], "dtls")) {
        socktest(argv[2], 0, 1);
    } else if (!strcmp(argv[1], "tcp")) {
        socktest(argv[2], 1, 0);
    } else if (!strcmp(argv[1], "tls")) {
        socktest(argv[2], 1, 1);
#ifndef __WIN32
    } else if (!strcmp(argv[1], "unix_d")) {
        unixsocktest(argv[2], SOCK_DGRAM);
    } else if (!strcmp(argv[1], "unix_s")) {
        unixsocktest(argv[2], SOCK_STREAM);
#endif
    } else {
        printf("Invalid Option\n");
    }
}

Output

./socket tls ::1
Socket Client/Server Echo (TCP/TLS/UDP/DTLS)

Copyright (C) 2013 Gregory Hinton Nietsky <gregory@distrotech.co.za>

        http://www.distrotech.co.za

    This program comes with ABSOLUTELY NO WARRANTY
    This is free software, and you are welcome to redistribute it
    under certain conditions.

......./dtsapplib/private$ [S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18
[S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18
[S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18
[S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18
[S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18
[S] client 1 19
[C] client 1 17
[S] client 2 20
[C] client 2 18