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/*
* Copyright (C) 2022 Amazon.com Inc. or its affiliates. All rights reserved.
* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
*/
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#ifdef __wasi__
#include <wasi_socket_ext.h>
#endif
static void
init_sockaddr_inet(struct sockaddr_in *addr)
{
addr->sin_family = AF_INET;
addr->sin_port = htons(1234);
}
static void
init_sockaddr_inet6(struct sockaddr_in6 *addr)
{
addr->sin6_family = AF_INET6;
addr->sin6_port = htons(1234);
}
static int
get_ip_addr_type(char *addr, char *buf)
{
if (inet_pton(AF_INET6, addr, buf)) {
return AF_INET6;
}
if (inet_pton(AF_INET, addr, buf)) {
return AF_INET;
}
return -1;
}
static int
is_valid_addr_type(int addr_type)
{
return !(addr_type == -1
|| (addr_type != AF_INET && addr_type != AF_INET6));
}
int
main(int argc, char *argv[])
{
struct ipv6_mreq ipv6_group;
struct ip_mreq ipv4_group;
int sd;
int datalen;
char databuf[1024] = { 0 };
char multicast_addr_buffer[16];
struct sockaddr_storage local_address = { 0 };
int addr_type = -1;
int read_result;
int bool_opt = 1;
if (argc < 2) {
printf("Usage is <Multicast IP>\n");
return EXIT_FAILURE;
}
addr_type = get_ip_addr_type(argv[1], multicast_addr_buffer);
if (!is_valid_addr_type(addr_type)) {
printf("Not a valid ipv4 or ipv6 address\n");
return EXIT_FAILURE;
}
if ((sd = socket(addr_type, SOCK_DGRAM, 0)) == -1) {
perror("Failed opening socket");
return EXIT_FAILURE;
}
if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &bool_opt, sizeof(bool_opt))
== -1) {
perror("Failed setting SO_REUSEADDR");
goto fail;
}
if (addr_type == AF_INET) {
init_sockaddr_inet((struct sockaddr_in *)&local_address);
memcpy(&(ipv4_group.imr_multiaddr), multicast_addr_buffer, 4);
ipv4_group.imr_interface.s_addr = htonl(INADDR_ANY);
if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &ipv4_group,
sizeof(ipv4_group))
== -1) {
perror("Failed joining IPv4 multicast group");
goto fail;
}
}
else {
init_sockaddr_inet6((struct sockaddr_in6 *)&local_address);
memcpy(&(ipv6_group.ipv6mr_multiaddr), multicast_addr_buffer, 16);
ipv6_group.ipv6mr_interface = 0;
if (setsockopt(sd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &ipv6_group,
sizeof(ipv6_group))
== -1) {
perror("Failed joining IPv6 multicast group");
goto fail;
}
}
if (bind(sd, (struct sockaddr *)&local_address, sizeof(local_address))
== -1) {
perror("Failed binding socket");
goto fail;
}
printf("Joined multicast group. Waiting for datagram...\n");
datalen = sizeof(databuf) - 1;
read_result = read(sd, databuf, datalen);
if (read_result < 0) {
perror("Failed binding socket");
goto fail;
}
printf("Reading datagram message...OK.\n");
printf("The message from multicast server is: \"%s\"\n", databuf);
close(sd);
return EXIT_SUCCESS;
fail:
close(sd);
return EXIT_FAILURE;
}
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