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Class: UDPSocket

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::IPSocket, ::BasicSocket, ::IO
Instance Chain:
self, ::IPSocket, ::BasicSocket, ::IO
Inherits: IPSocket
Defined in: ext/socket/udpsocket.c,
ext/socket/lib/socket.rb

Overview

UDPSocket represents a UDP/IP socket.

Class Attribute Summary

::BasicSocket - Inherited

.do_not_reverse_lookup

Gets the global do_not_reverse_lookup flag.
.do_not_reverse_lookup=

Sets the global do_not_reverse_lookup flag.

Class Method Summary

::IPSocket - Inherited

.getaddress

Lookups the IP address of host.

::BasicSocket - Inherited

.for_fd

Returns a socket object which contains the file descriptor, fd.

Instance Attribute Summary

::BasicSocket - Inherited

#do_not_reverse_lookup

Gets the do_not_reverse_lookup flag of basicsocket.
#do_not_reverse_lookup=

Sets the do_not_reverse_lookup flag of basicsocket.

Instance Method Summary

::IPSocket - Inherited

#addr

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

Return a string describing this ::IPSocket object.
#peeraddr

Returns the remote address as an array which contains address_family, port, hostname and numeric_address.
#recvfrom

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

::BasicSocket - Inherited

#close_read

Disallows further read using shutdown system call.
#close_write

Disallows further write using shutdown system call.
#connect_address

Returns an address of the socket suitable for connect in the local machine.
#getpeereid

Returns the user and group on the peer of the UNIX socket.
#getpeername

Returns the remote address of the socket as a sockaddr string.
#getsockname

Returns the local address of the socket as a sockaddr string.
#getsockopt

Gets a socket option.
#local_address

Returns an ::Addrinfo object for local address obtained by getsockname.
#recv

Receives a message.
#recv_nonblock

Receives up to maxlen bytes from socket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor.
#recvmsg

recvmsg receives a message using recvmsg(2) system call in blocking manner.
#recvmsg_nonblock

recvmsg receives a message using recvmsg(2) system call in non-blocking manner.
#remote_address

Returns an ::Addrinfo object for remote address obtained by getpeername.
#send

send mesg via basicsocket.
#sendmsg

sendmsg sends a message using sendmsg(2) system call in blocking manner.
#sendmsg_nonblock

sendmsg_nonblock sends a message using sendmsg(2) system call in non-blocking manner.
#setsockopt

Sets a socket option.
#shutdown

Calls shutdown(2) system call.
#__recvmsg, #__recvmsg_nonblock, #__sendmsg, #__sendmsg_nonblock, #read_nonblock, #write_nonblock, #__read_nonblock, #__recv_nonblock, #__write_nonblock

Constructor Details

.new([address_family]) ⇒ socket

Creates a new UDPSocket object.

address_family should be an integer, a string or a symbol: Socket::AF_INET, “AF_INET”, :INET, etc.

require 'socket'

UDPSocket.new                   #=> #<UDPSocket:fd 3>
UDPSocket.new(Socket::AF_INET6) #=> #<UDPSocket:fd 4>
[ GitHub ] 

  


# File 'ext/socket/udpsocket.c', line 28



static VALUE
udp_init(int argc, VALUE *argv, VALUE sock)
{
    VALUE arg;
    int family = AF_INET;
    int fd;

    if (rb_scan_args(argc, argv, "01", &arg) == 1) {
	family = rsock_family_arg(arg);
    }
    fd = rsock_socket(family, SOCK_DGRAM, 0);
    if (fd < 0) {
	rb_sys_fail("socket(2) - udp");
    }

    return rsock_init_sock(sock, fd);
}


  







Instance Method Details



  

    #__recvfrom_nonblock(len, flg, str, ex)   (private)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'ext/socket/udpsocket.c', line 226



static VALUE
udp_recvfrom_nonblock(VALUE sock, VALUE len, VALUE flg, VALUE str, VALUE ex)
{
    return rsock_s_recvfrom_nonblock(sock, len, flg, str, ex, RECV_IP);
}


  








  

    #bind(host, port) # = > 0))    



  

    

Binds udpsocket to host:port.



u1 = UDPSocket.new
u1.bind("127.0.0.1", 4913)
u1.send "message-to-self", 0, "127.0.0.1", 4913
p u1.recvfrom(10) #=> ["message-to", ["AF_INET", 4913, "localhost", "127.0.0.1"]]


  



  [ GitHub ]


  

  


# File 'ext/socket/udpsocket.c', line 131



static VALUE
udp_bind(VALUE sock, VALUE host, VALUE port)
{
    struct udp_arg arg;
    VALUE ret;

    GetOpenFile(sock, arg.fptr);
    arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0);
    ret = rb_ensure(udp_bind_internal, (VALUE)&arg,
		    rsock_freeaddrinfo, (VALUE)arg.res);
    if (!ret) rsock_sys_fail_host_port("bind(2)", host, port);
    return INT2FIX(0);
}


  








  

    #connect(host, port)  ⇒ 0   



  

    

Connects udpsocket to host:port.



This makes possible to send without destination address.



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


  



  [ GitHub ]


  

  


# File 'ext/socket/udpsocket.c', line 86



static VALUE
udp_connect(VALUE sock, VALUE host, VALUE port)
{
    struct udp_arg arg;
    VALUE ret;

    GetOpenFile(sock, arg.fptr);
    arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0);
    ret = rb_ensure(udp_connect_internal, (VALUE)&arg,
		    rsock_freeaddrinfo, (VALUE)arg.res);
    if (!ret) rsock_sys_fail_host_port("connect(2)", host, port);
    return INT2FIX(0);
}


  








  

    #recvfrom_nonblock(maxlen [, flags[, outbuf [, options]]])  ⇒ Array, sender_inet_addr   



  

    

Receives up to maxlen bytes from udpsocket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_ options. The first element of the results, mesg, is the data received. The second element, sender_inet_addr, is an array to represent the sender address.



When recvfrom(2) returns 0, Socket#recvfrom_nonblock returns an empty string as data. It means an empty packet.



Parameters


  • 

    maxlen - the number of bytes to receive from the socket
    

  • 

    flags - zero or more of the MSG_ options
    

  • 

    outbuf - destination String buffer
    

  • 

    options - keyword hash, supporting exception: false
    




Example



require 'socket'
s1 = UDPSocket.new
s1.bind("127.0.0.1", 0)
s2 = UDPSocket.new
s2.bind("127.0.0.1", 0)
s2.connect(*s1.addr.values_at(3,1))
s1.connect(*s2.addr.values_at(3,1))
s1.send "aaa", 0
begin # emulate blocking recvfrom
  p s2.recvfrom_nonblock(10)  #=> ["aaa", ["AF_INET", 33302, "localhost.localdomain", "127.0.0.1"]]
rescue IO::WaitReadable
  IO.select([s2])
  retry
end



Refer to Socket#recvfrom for the exceptions that may be thrown if the call to recvfrom_nonblock fails.



recvfrom_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.



If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying recvfrom_nonblock.



By specifying a keyword argument exception to false, you can indicate that recvfrom_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.



See



  



  [ GitHub ]


  

  


# File 'ext/socket/lib/socket.rb', line 1271



def recvfrom_nonblock(len, flag = 0, outbuf = nil, exception: true)
  __recvfrom_nonblock(len, flag, outbuf, exception)
end


  








  

    

      #send(mesg, flags, host, port)  ⇒ numbytes_sent 
      #send(mesg, flags, sockaddr_to)  ⇒ numbytes_sent 
      #send(mesg, flags)  ⇒ numbytes_sent 
    

  



  

    

Sends mesg via udpsocket.



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



u1 = UDPSocket.new
u1.bind("127.0.0.1", 4913)

u2 = UDPSocket.new
u2.send "hi", 0, "127.0.0.1", 4913

mesg, addr = u1.recvfrom(10)
u1.send mesg, 0, addr[3], addr[1]

p u2.recv(100) #=> "hi"


  





  


  [ GitHub ]


  

  


# File 'ext/socket/udpsocket.c', line 202



static VALUE
udp_send(int argc, VALUE *argv, VALUE sock)
{
    VALUE flags, host, port;
    struct udp_send_arg arg;
    VALUE ret;

    if (argc == 2 || argc == 3) {
	return rsock_bsock_send(argc, argv, sock);
    }
    rb_scan_args(argc, argv, "4", &arg.sarg.mesg, &flags, &host, &port);

    StringValue(arg.sarg.mesg);
    GetOpenFile(sock, arg.fptr);
    arg.sarg.fd = arg.fptr->fd;
    arg.sarg.flags = NUM2INT(flags);
    arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0);
    ret = rb_ensure(udp_send_internal, (VALUE)&arg,
		    rsock_freeaddrinfo, (VALUE)arg.res);
    if (!ret) rsock_sys_fail_host_port("sendto(2)", host, port);
    return ret;
}