IPv6 related

Address already in use

When listening to a port at the same time IPv4 and IPv6 when , function bind The function will fail to execute , Tips “bind : Address already in use”.
reason ：ipv6 Of socket By default, you will also receive ipv4 Message of , Different socket Cannot monitor the same IP The same port under
Method ： Set up ipv6 Of socket Only receive ipv6 Address message

int on = 1;
if(0 > setsockopt(fd_v6, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)))
{
    
	perror("setsockopt");
	return -1;
}

IPv6 relevant

1. fe80 Local link IPv6 Address , For local use only , Cannot be used for outbound communications
2. visit ipv6 Of web The server http://[fe80::aa:bb:cc:dd], Bracketed access
3. ping IPv6, If it is fe80 At the beginning , be ping6 fe80::aa:bb:cc:dd%xx, add to % Add the network card name after it
4. ping IPv6, If the fe80 At the beginning , be ping6 fe80::aa:bb:cc:dd that will do
5. Use boost When adding a network link ,IPv6 Should also be fe80::aa:bb:cc:dd%xx Only then can

How to use boost Of asio Realize simultaneous monitoring IPv4 and IPv6

boost::asio::io_service io_serv;
boost::asio::ip::tcp::acceotpr acceotor_v4(io_serv);
boost::asio::ip::tcp::acceotpr acceotor_v6(io_serv);

acceotor_v4.open(ip::tcp::v4());
acceotor_v6.open(ip::tcp::v6());

Set properties
// Set up IPv6 Receive only IPv6 Address
setsockopt(fd_v6, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on);
No address binding
// binding IPv4
acceotor_v4.bind(ip::tcp::endpoint(ip::tcp::v4(), port));
// binding IPv6
acceotor_v6.bind(ip::tcp::endpoint(ip::tcp::v6(), port));
Address binding
boost::asio::ip::address addr = boost::asio::ip::address::from_string(ip);
acceotor_v4.bind(ip::tcp::endpoint(addr, port));