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/*##############################################################################
# Copyright (c) 2017 ZTE Coreporation and others.
# hu.zhijiang@zte.com.cn
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
##############################################################################*/
#include <fcntl.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "buffer.h"
#include "udp-common.h"
#include "misc.h"
struct mc_info mcinfo;
int init_mcast_socket(struct in_addr *local_addr,
struct sockaddr_in *maddr)
{
struct ip_mreqn mreqn; /* multicast request new */
int ms; /* multicast socket */
u_short msock_port;
struct sockaddr_in bind_addr;
int msock_reuse = MCAST_REUSE;
u_char msock_loop = MCAST_LOOP;
u_char msock_ttl = MCAST_TTL;
if ((ms = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
crit("socket() failed, error allocating multicast socket");
}
// In order to let client and server on same host to use same port
if (setsockopt(ms, SOL_SOCKET, SO_REUSEADDR,
&msock_reuse, sizeof(msock_reuse)) < 0) {
crit("setsockopt() failed, can't set reuse flag");
}
if (setsockopt(ms, IPPROTO_IP, IP_MULTICAST_TTL,
&msock_ttl,sizeof(msock_ttl)) < 0) {
crit("setsockopt() failed, can't set ttl value");
}
if (setsockopt(ms, IPPROTO_IP, IP_MULTICAST_LOOP,
&msock_loop, sizeof(msock_loop)) < 0) {
crit("setsockopt() failed, can't set multicast packet looping");
}
/* TODO: Do we neet non-block? */
log(4, "Using multicast address: %s:%d",
inet_ntoa(maddr->sin_addr), ntohs(maddr->sin_port));
mreqn.imr_multiaddr = maddr->sin_addr;
mreqn.imr_address = *local_addr;
mreqn.imr_ifindex = 0;
/* Interface and remote mcast address choosing */
/* This tell interface which has mreqn.imr_address to join
mreqn.imr_multiaddr group, it has nothing to do with socket, port, and
mreqn.imr_address. */
if (setsockopt(ms, IPPROTO_IP, IP_ADD_MEMBERSHIP,
&mreqn, sizeof(mreqn)) < 0) {
crit("setsockopt() failed, %s can't join multicast group",
inet_ntoa(*local_addr));
}
/* local address choosing */
/* This tell kernel to use interface which has mreqn.imr_address as device
and mreqn.imr_address as source addr when sending any multicast through
socket. */
if (setsockopt(ms, IPPROTO_IP, IP_MULTICAST_IF,
&mreqn, sizeof(mreqn)) < 0) {
crit("setsockopt() failed to IP_MULTICAST_IF.\n");
}
/* Local port choosing, remote port is choosed when calling sendto()! */
/* This let us uses specific udp port number as source port when sending
any multicast datagrams. So ip in maddr is useless here and should be
INADDR_ANY, otherwise, bind will return Invalid argument. */
msock_port = ntohs(maddr->sin_port);
bind_addr = make_addr(0, msock_port);
if (bind(ms, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) < 0) {
crit("bind() error, can't bind mcast port");
}
return ms;
}
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