ip.c

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#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) */