class IPSocket

static VALUE
ip_s_getaddress(VALUE obj, VALUE host)
{
    union_sockaddr addr;
    struct rb_addrinfo *res = rsock_addrinfo(host, Qnil, AF_UNSPEC, SOCK_STREAM, 0);
    socklen_t len = res->ai->ai_addrlen;

    /* just take the first one */
    memcpy(&addr, res->ai->ai_addr, len);
    rb_freeaddrinfo(res);

    return rsock_make_ipaddr(&addr.addr, len);
}

Lookups the IP address of host.

require 'socket'

IPSocket.getaddress("localhost")     #=> "127.0.0.1"
IPSocket.getaddress("ip6-localhost") #=> "::1"

static VALUE
ip_addr(int argc, VALUE *argv, VALUE sock)
{
    rb_io_t *fptr;
    union_sockaddr addr;
    socklen_t len = (socklen_t)sizeof addr;
    int norevlookup;

    GetOpenFile(sock, fptr);

    if (argc < 1 || !rsock_revlookup_flag(argv[0], &norevlookup))
        norevlookup = fptr->mode & FMODE_NOREVLOOKUP;
    if (getsockname(fptr->fd, &addr.addr, &len) < 0)
        rb_sys_fail("getsockname(2)");
    return rsock_ipaddr(&addr.addr, len, norevlookup);
}

Returns the local address as an array which contains address_family, port, hostname and numeric_address.

If reverse_lookup is true or :hostname, hostname is obtained from numeric_address using reverse lookup. Or if it is false, or :numeric, hostname is same as numeric_address. Or if it is nil or omitted, obeys to ipsocket.do_not_reverse_lookup. See Socket.getaddrinfo also.

TCPSocket.open("www.ruby-lang.org", 80) {|sock|
  p sock.addr #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(true)  #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(false) #=> ["AF_INET", 49429, "192.168.0.128", "192.168.0.128"]
  p sock.addr(:hostname)  #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(:numeric)   #=> ["AF_INET", 49429, "192.168.0.128", "192.168.0.128"]
}

static VALUE
ip_peeraddr(int argc, VALUE *argv, VALUE sock)
{
    rb_io_t *fptr;
    union_sockaddr addr;
    socklen_t len = (socklen_t)sizeof addr;
    int norevlookup;

    GetOpenFile(sock, fptr);

    if (argc < 1 || !rsock_revlookup_flag(argv[0], &norevlookup))
        norevlookup = fptr->mode & FMODE_NOREVLOOKUP;
    if (getpeername(fptr->fd, &addr.addr, &len) < 0)
        rb_sys_fail("getpeername(2)");
    return rsock_ipaddr(&addr.addr, len, norevlookup);
}

Returns the remote address as an array which contains address_family, port, hostname and numeric_address. It is defined for connection oriented socket such as TCPSocket.

If reverse_lookup is true or :hostname, hostname is obtained from numeric_address using reverse lookup. Or if it is false, or :numeric, hostname is same as numeric_address. Or if it is nil or omitted, obeys to ipsocket.do_not_reverse_lookup. See Socket.getaddrinfo also.

TCPSocket.open("www.ruby-lang.org", 80) {|sock|
  p sock.peeraddr #=> ["AF_INET", 80, "carbon.ruby-lang.org", "221.186.184.68"]
  p sock.peeraddr(true)  #=> ["AF_INET", 80, "carbon.ruby-lang.org", "221.186.184.68"]
  p sock.peeraddr(false) #=> ["AF_INET", 80, "221.186.184.68", "221.186.184.68"]
  p sock.peeraddr(:hostname) #=> ["AF_INET", 80, "carbon.ruby-lang.org", "221.186.184.68"]
  p sock.peeraddr(:numeric)  #=> ["AF_INET", 80, "221.186.184.68", "221.186.184.68"]
}

static VALUE
ip_recvfrom(int argc, VALUE *argv, VALUE sock)
{
    return rsock_s_recvfrom(sock, argc, argv, RECV_IP);
}

Receives a message and return the message as a string and an address which the message come from.

maxlen is the maximum number of bytes to receive.

flags should be a bitwise OR of Socket::MSG_* constants.

ipaddr is same as IPSocket#{peeraddr,addr}.

u1 = UDPSocket.new
u1.bind("127.0.0.1", 4913)
u2 = UDPSocket.new
u2.send "uuuu", 0, "127.0.0.1", 4913
p u1.recvfrom(10) #=> ["uuuu", ["AF_INET", 33230, "localhost", "127.0.0.1"]]