#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/ioctl.h>

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

int
do_connect(int s, const char* destaddr, unsigned short destport)
{
    struct sockaddr_in6 sa;
    socklen_t len;
    int rc;

    len = sizeof(struct sockaddr_in6);
    memset(&sa, 0, len);
    sa.sin6_family = AF_INET6;
    if (inet_pton(AF_INET6, destaddr, &sa.sin6_addr) <= 0)
    {
        printf("inet_pton failed\n");
        exit(1);
    }
    sa.sin6_port = htons(destport);

    rc = connect(s, (struct sockaddr*)&sa, len);
    if (rc == -1 && errno == EINPROGRESS)
    {
        fd_set fds;
        FD_ZERO(&fds);
        FD_SET(s, &fds);
        do
        {
            rc = select(s+1, NULL, &fds, NULL, NULL);
        }
        while (rc == -1 && errno == EINTR);
        if (rc != 1)
        {
            printf("select failed\n");
            exit(1);
        }
        len = sizeof(rc);
        if (getsockopt(s, SOL_SOCKET, SO_ERROR, &rc, &len) != 0)
        {
            printf("get SO_ERROR failed\n");
            exit(1);
        }
        printf("async connect to %s returned %s\n", destaddr, strerror(rc));
        return rc;
    }
    printf("sync  connect to %s returned %s\n", destaddr, strerror(errno));
    return errno;
}

int
main(int argc, char** argv)
{
    int s;
    int rc;
    int tmp;

    if (argc != 5)
    {
        printf("usage: %s <host6> <host4> <port> <NB>\n", argv[0]);
        exit(1);
    }

    s = socket(AF_INET6, SOCK_STREAM, 0);
    if (s == -1)
    {
        perror("socket");
        exit(1);
    }

    tmp = atoi(argv[4]);
    ioctl(s, FIONBIO, &tmp);

    /* attempt v6 connect, verify EHOSTUNREACH */
    rc = do_connect(s, argv[1], atoi(argv[3]));
    if (rc == 0)
    {
        exit(1);
    }

    /* attempt v4 connect, 2.6.x returns ECONNABORTED */
    rc = do_connect(s, argv[2], atoi(argv[3]));
    if (rc == 0)
    {
        exit(1);
    }

    /* retry, verify success */
    rc = do_connect(s, argv[2], atoi(argv[3]));
    if (rc == 0)
    {
        exit(1);
    }

    close(s);
    return 0;
}