getaddrinfo.c example

getaddrinfo.c (text/plain), 1.06 KB, created by Maxim Kammerer on 2012-08-20 03:16:10 UTC

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>

static int xtables_getportbyname(const char *name)
{
    struct addrinfo *res = NULL, *p;
    int ret;

    printf("before\n");
    ret = getaddrinfo(NULL, name, NULL, &res);
    printf("after\n");

    if (ret < 0)
        return -1;
    ret = -1;
    for (p = res; p != NULL; p = p->ai_next) {
        if (p->ai_family == AF_INET6) {
            ret = ((struct sockaddr_in6 *)p->ai_addr)->sin6_port;
            break;
        } else if (p->ai_family == AF_INET) {
            ret = ((struct sockaddr_in *)p->ai_addr)->sin_port;
            break;
        }
    }
    freeaddrinfo(res);
    if (ret < 0)
        return ret;
    return ntohs(ret);
}

int main() {
    struct servent *service;
    short port = -1;
    int port2 = -1;

    if ((service = getservbyname("bootps", NULL)) != NULL)
        port = ntohs((unsigned short) service->s_port);

    printf("getservbyname: %d\n", port);

    port2 = xtables_getportbyname("bootps");
    printf("getaddrinfo: %d\n", port2);

    return 0;
}