udp6

udp6 is an interface to User Datagram Protocol sockets over IPv4 and IPv6.

  1. udp6
  2. Overview
  3. Interface
  4. UDP ports
  5. Example
  6. Bugs and limitations
  7. About this egg
    1. Author
    2. Version History
    3. License

Overview

This is a superset of the functionality of the udp extension, primarily adding IPv6 support while maintaining a backwards-compatible API. It is implemented on top of the socket egg,

Interface

[procedure] (udp-open-socket)
[procedure] (udp-open-socket*)

Returns a new UDP socket object, which is simply a datagram socket object created by the socket egg.

The starred version is provided for API compatibility; here it does the same as the unstarred version, as all sockets are nonblocking.

[procedure] (udp-bind! SOCKET HOST PORT)

Binds a UDP socket to an address and port as specified by HOST and PORT. HOST may be a string consisting of an IP address or hostname, or #f, in which case the unspecified address is used. If PORT is 0, a port will be allocated by the system automatically.

[procedure] (udp-connect! SOCKET HOST PORT)

Connect a socket. In the case of UDP this does nothing more than associate a peer address with the socket in the kernel for use with later calls to send(2). UDP is a connectionless protocol.

[procedure] (udp-send SOCKET STRING)

Send the bytes in STRING through SOCKET to its peer, as specified with a previous call to udp-connect!. If the socket is not connected, the system will return an error.

[procedure] (udp-sendto SOCKET HOST PORT STRING)

Send the bytes in STRING through SOCKET to PORT on HOST.

[procedure] (udp-recv SOCKET LENGTH)

Receive a packet and store the data in string of size LENGTH. Returns two values: the number of bytes received and the string consisting the message.

[procedure] (udp-recvfrom SOCKET LENGTH)

Same as udp-recv except that two additional values are returned: the host string and port number from which the packet was received.

[procedure] (udp-close-socket SOCKET)

Close a socket.

[procedure] (udp-socket? THING)

Test whether THING is a UDP socket.

[procedure] (udp-bound? SOCKET)

Test whether a UDP socket is bound to a local address and port.

[procedure] (udp-connected? SOCKET)

Test whether a peer address and port has been associated with a UDP socket with a call to udp-connect!.

[procedure] (udp-bound-port SOCKET)

Returns the port to which the socket is bound.

UDP ports

Input and output Scheme ports can be created from a connected UDP socket using socket-i/o-ports from the socket egg. An example will be provided in the future.

Example

(use udp6)
(define s (udp-open-socket))
(udp-connect! s "localhost" 13)  ; daytime service
(udp-send s "\n")
(receive (n data host port) (udp-recvfrom s 64)
  (print n " bytes from " host ":" port ": " data))
(udp-close-socket s)
 
;; Prints one of the following:
;; 26 bytes from 127.0.0.1:13: Wed Dec 24 11:53:14 2003
;; 26 bytes from ::1:13: Wed Dec 24 11:53:14 2003

This example can also be written directly with the socket egg:

(use socket)
(define s (socket-connect/ai
           (address-information "localhost" 13 type: sock/dgram)))
(socket-send s "\n")
(receive (data addr) (socket-receive-from s 64)
  (print (string-length data) " bytes from "
         (sockaddr->string addr) ": " data))
(socket-close s)

;; Prints one of the following:
;; 26 bytes from 127.0.0.1:13: Sat Feb 12 03:53:46 CST 2011
;; 26 bytes from [::1]:13: Sat Feb 12 03:53:46 CST 2011

Bugs and limitations

Multicast is not yet implemented.

About this egg

Author

Jim Ursetto. Originally by Category 5, with several enhancements by Daishi Kato, but has been rewritten on top of the socket egg.

Version History

0.1
Initial release

See udp for previous history (up to 1.14).

License

Copyright (c) 2011, Jim Ursetto
Copyright (c) 2003-2004, Category 5
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

  Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer. Redistributions in
  binary form must reproduce the above copyright notice, this list of
  conditions and the following disclaimer in the documentation and/or
  other materials provided with the distribution. Neither the name of the
  author nor the names of its contributors may be used to endorse or
  promote products derived from this software without specific prior
  written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.