openssl1.0/demos/tunala/ip.c

#include "tunala.h"

#ifndef NO_IP

# define IP_LISTENER_BACKLOG 511/* So if it gets masked by 256 or some other
                                 * such value it'll still be respectable */

/* Any IP-related initialisations. For now, this means blocking SIGPIPE */
int ip_initialise(void)
{
    struct sigaction sa;

    sa.sa_handler = SIG_IGN;
    sa.sa_flags = 0;
    sigemptyset(&sa.sa_mask);
    if (sigaction(SIGPIPE, &sa, NULL) != 0)
        return 0;
    return 1;
}

int ip_create_listener_split(const char *ip, unsigned short port)
{
    struct sockaddr_in in_addr;
    int fd = -1;
    int reuseVal = 1;

    /* Create the socket */
    if ((fd = socket(PF_INET, SOCK_STREAM, 0)) == -1)
        goto err;
    /* Set the SO_REUSEADDR flag - servers act weird without it */
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)(&reuseVal),
                   sizeof(reuseVal)) != 0)
        goto err;
    /* Prepare the listen address stuff */
    in_addr.sin_family = AF_INET;
    memcpy(&in_addr.sin_addr.s_addr, ip, 4);
    in_addr.sin_port = htons(port);
    /* Bind to the required port/address/interface */
    if (bind(fd, (struct sockaddr *)&in_addr, sizeof(struct sockaddr_in)) !=
        0)
        goto err;
    /* Start "listening" */
    if (listen(fd, IP_LISTENER_BACKLOG) != 0)
        goto err;
    return fd;
 err:
    if (fd != -1)
        close(fd);
    return -1;
}

int ip_create_connection_split(const char *ip, unsigned short port)
{
    struct sockaddr_in in_addr;
    int flags, fd = -1;

    /* Create the socket */
    if ((fd = socket(PF_INET, SOCK_STREAM, 0)) == -1)
        goto err;
    /* Make it non-blocking */
    if (((flags = fcntl(fd, F_GETFL, 0)) < 0) ||
        (fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0))
        goto err;
    /* Prepare the connection address stuff */
    in_addr.sin_family = AF_INET;
    memcpy(&in_addr.sin_addr.s_addr, ip, 4);
    in_addr.sin_port = htons(port);
    /* Start a connect (non-blocking, in all likelihood) */
    if ((connect(fd, (struct sockaddr *)&in_addr,
                 sizeof(struct sockaddr_in)) != 0) && (errno != EINPROGRESS))
        goto err;
    return fd;
 err:
    if (fd != -1)
        close(fd);
    return -1;
}

static char all_local_ip[] = { 0x00, 0x00, 0x00, 0x00 };

int ip_parse_address(const char *address, const char **parsed_ip,
                     unsigned short *parsed_port, int accept_all_ip)
{
    char buf[256];
    struct hostent *lookup;
    unsigned long port;
    const char *ptr = strstr(address, ":");
    const char *ip = all_local_ip;

    if (!ptr) {
        /*
         * We assume we're listening on all local interfaces and have only
         * specified a port.
         */
        if (!accept_all_ip)
            return 0;
        ptr = address;
        goto determine_port;
    }
    if ((ptr - address) > 255)
        return 0;
    memset(buf, 0, 256);
    memcpy(buf, address, ptr - address);
    ptr++;
    if ((lookup = gethostbyname(buf)) == NULL) {
        /*
         * Spit a message to differentiate between lookup failures and bad
         * strings.
         */
        fprintf(stderr, "hostname lookup for '%s' failed\n", buf);
        return 0;
    }
    ip = lookup->h_addr_list[0];
 determine_port:
    if (strlen(ptr) < 1)
        return 0;
    if (!int_strtoul(ptr, &port) || (port > 65535))
        return 0;
    *parsed_ip = ip;
    *parsed_port = (unsigned short)port;
    return 1;
}

int ip_create_listener(const char *address)
{
    const char *ip;
    unsigned short port;

    if (!ip_parse_address(address, &ip, &port, 1))
        return -1;
    return ip_create_listener_split(ip, port);
}

int ip_create_connection(const char *address)
{
    const char *ip;
    unsigned short port;

    if (!ip_parse_address(address, &ip, &port, 0))
        return -1;
    return ip_create_connection_split(ip, port);
}

int ip_accept_connection(int listen_fd)
{
    return accept(listen_fd, NULL, NULL);
}

#endif                          /* !defined(NO_IP) */