#include <sys/socket.h>
#include <netinet/in.h>
#include <strings.h>
#include <string.h>
#include <err.h>

int
main(int argc, char **argv)
{
        struct sockaddr_in addr1, addr2;
        int fd1, fd2, enable = 1;

        addr1.sin_family = AF_INET;
        addr1.sin_port = htons(6666);
        addr1.sin_addr.s_addr = INADDR_ANY;
        /* fill sin_zero explicitly with garbage */
        memset(addr1.sin_zero, 0xd0, sizeof(addr1.sin_zero));

        addr2.sin_family = AF_INET;
        addr2.sin_port = htons(6666);
        addr2.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
        /* fill sin_zero explicitly with garbage */
        memset(addr2.sin_zero, 0xd0, sizeof(addr2.sin_zero));


        if ((fd1 = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
                err(1, "socket1");

        if (setsockopt(fd1, SOL_SOCKET, SO_REUSEPORT, &enable,
            sizeof(int)) < 0)
                err(1, "setsockopt1");

        if (bind(fd1, (struct sockaddr *)&addr1, sizeof(addr1)) == -1)
                err(1, "bind1");

        if ((fd2 = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
                err(1, "socket1");

        if (setsockopt(fd2, SOL_SOCKET, SO_REUSEPORT, &enable,
            sizeof(int)) < 0)
                err(1, "setsockopt2");

        if (bind(fd2, (struct sockaddr *)&addr2, sizeof(addr2)) == -1)
                err(1, "bind2");

        return 0;
}