/*
 * Copyright 2010, Atis Elsts, the.kfx@gmail.com
 * Distributed under the terms of the MIT license.
 */


#include <unistd.h>
#include <memory.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>


const unsigned short TEST_PORT = 40000;


int
main(int argc, char *argv[])
{
        int socketFamily = AF_INET;

        int i = 1;
        if (argc > i) {
                if (!strcmp(argv[i], "-4")) {
                        i++;
                        socketFamily = AF_INET;
                } else if (!strcmp(argv[i], "-6")) {
                        i++;
                        socketFamily = AF_INET6;
                }
        }
        in_addr multicastSource;
        multicastSource.s_addr = 0;
        if (argc > i) {
                if (!strcmp(argv[i], "-s")) {
                        ++i;
                        if (inet_aton(argv[i], &multicastSource) == 0) {
                                fprintf(stderr, "IPv4 source address expected");
                                return -1;
                        }
                        ++i;
                }
        }

        int fd = socket(socketFamily, SOCK_DGRAM, 0);
        if (fd < 0) {
                perror("socket");
                return -1;
        }

        sockaddr_storage saddr;
        memset(&saddr, 0, sizeof(saddr));
        if (socketFamily == AF_INET) {
                sockaddr_in *sa = (sockaddr_in *) &saddr;
                sa->sin_family = AF_INET;
                sa->sin_port = htons(TEST_PORT);
                sa->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
        } else {
                sockaddr_in6 *sa = (sockaddr_in6 *) &saddr;
                sa->sin6_family = AF_INET6;
                sa->sin6_port = htons(TEST_PORT);
                // ff01::1 (all nodes multicast)
                sa->sin6_addr.s6_addr[0] = 0xff;
                sa->sin6_addr.s6_addr[1] = 0x01;
                sa->sin6_addr.s6_addr[15] = 0x01;
        }

        if (multicastSource.s_addr) {
                if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
                                &multicastSource, sizeof(multicastSource)) < 0) {
                        perror("setsockopt IP_MULTICAST_IF");
                        return -1;
                }
        }

        const char *buffer = "hello world";
        unsigned length = strlen(buffer);
        int status = sendto(fd, buffer, length, 0, (sockaddr *) &saddr,
                socketFamily == AF_INET ? sizeof(sockaddr_in) : sizeof(sockaddr_in6));
        if (status < length) {
                if (status < 0)
                        perror("sendto");
                else if (status == 0)
                        printf("no data sent!\n");
                else
                        printf("not all data sent!\n");
        } else
                printf("send(): success\n");

        close(fd);
        return 0;
}