udplite(7) [debian man page]

UDPLITE(7)						     Linux Programmer's Manual							UDPLITE(7)

NAME

       udplite - Lightweight User Datagram Protocol

SYNOPSIS

       #include <sys/socket.h>

       sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDPLITE);

DESCRIPTION

       This is an implementation of the Lightweight User Datagram Protocol (UDP-Lite), as described in RFC 3828.

       UDP-Lite is an extension of UDP (RFC 768) to support variable-length checksums.	This has advantages for some types of multimedia transport
       that may be able to make use of slightly damaged datagrams, rather than having them discarded by lower-layer protocols.

       The variable-length checksum coverage is set via a setsockopt(2) option.  If this option is not set, the only difference to UDP is in using
       a different IP protocol identifier (IANA number 136).

       The  UDP-Lite  implementation  is  a  full  extension of udp(7), i.e., it shares the same API and API behaviour, and in addition offers two
       socket options to control the checksum coverage.

   Address Format
       UDP-Litev4 uses the sockaddr_in address format described in ip(7).  UDP-Litev6 uses the sockaddr_in6 address format described in ipv6(7).

   Socket Options
       To set or get a UDP-Lite socket option, call getsockopt(2) to read or setsockopt(2) to write the option with the option level argument  set
       to IPPROTO_UDPLITE.  In addition, all IPPROTO_UDP socket options are valid on a UDP-Lite socket.  See udp(7) for more information.

       The following two options are specific to UDP-Lite.

       UDPLITE_SEND_CSCOV
	      This option sets the sender checksum coverage and takes an int as argument, with a checksum coverage value in the range 0..2^16-1.

	      A  value	of  0 means that the entire datagram is always covered.  Values from 1-7 are illegal (RFC 3828, 3.1) and are rounded up to
	      the minimum coverage of 8.

	      With regard to IPv6 jumbograms (RFC 2675), the UDP-Litev6 checksum coverage is limited to the first 2^16-1 octets, as per  RFC 3828,
	      3.5.  Higher values are therefore silently truncated to 2^16-1.  If in doubt, the current coverage value can always be queried using
	      getsockopt(2).

       UDPLITE_RECV_CSCOV
	      This is the receiver-side analogue and uses the same argument format and value range as  UDPLITE_SEND_CSCOV.   This  option  is  not
	      required to enable traffic with partial checksum coverage.  Its function is that of a traffic filter: when enabled, it instructs the
	      kernel to drop all packets which have a coverage less than the specified coverage value.

	      When the value of UDPLITE_RECV_CSCOV exceeds the actual packet coverage, incoming packets are silently dropped, but may  generate  a
	      warning message in the system log.

ERRORS

       All errors documented for udp(7) may be returned.  UDP-Lite does not add further errors.

BUGS

       Where glibc support is missing, the following definitions are needed:

	   #define IPPROTO_UDPLITE     136
	   #define UDPLITE_SEND_CSCOV  10
	   #define UDPLITE_RECV_CSCOV  11

FILES

       /proc/net/snmp - basic UDP-Litev4 statistics counters.
       /proc/net/snmp6 - basic UDP-Litev6 statistics counters.

VERSIONS

       UDP-Litev4/v6 first appeared in Linux 2.6.20.

SEE ALSO

       ip(7), ipv6(7), socket(7), udp(7)

       RFC 3828 for the Lightweight User Datagram Protocol (UDP-Lite).

       Documentation/networking/udplite.txt in the Linux kernel source tree

COLOPHON

       This  page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2008-12-03								UDPLITE(7)

Check Out this Related Man Page

udp(4p) 																   udp(4p)

Name
       udp - Internet User Datagram Protocol

Syntax
       #include <sys/socket.h>
       #include <netinet/in.h>

       s = socket(AF_INET, SOCK_DGRAM, 0);

Description
       UDP  is	a  simple,  unreliable datagram protocol that is used to support the SOCK_DGRAM abstraction for the Internet protocol family.  UDP
       sockets are connectionless and are normally used with the and calls, though the call can also be used to fix  the  destination  for  future
       packets (in which case the or and or system calls may be used).

       UDP  address  formats are identical to those used by TCP.  In particular, UDP provides a port identifier in addition to the normal Internet
       address format.	Note that the UDP port space is separate from the TCP port space (for example,	a UDP port may not be ``connected''  to  a
       TCP  port).   In  addition  broadcast  packets  can be sent (assuming the underlying network supports this) by using a reserved ``broadcast
       address''; this address is network interface dependent.	The SO_BROADCAST option must be set on the socket for broadcasting to succeed.

Diagnostics
       A socket operation may fail with one of the following errors returned:

       [EISCONN]      Try to establish a connection on a socket which already has one, or when trying to send  a  datagram  with  the  destination
		      address specified and the socket already connected.

       [ENOTCONN]     Try to send a datagram, but no destination address is specified, and the socket has not been connected.

       [ENOBUFS]      The system runs out of memory for an internal data structure.

       [EADDRINUSE]   An attempt is made to create a socket with a port that has already been allocated.

       [EADDRNOTAVAIL]
		      An attempt is made to create a socket with a network address for which no network interface exists.

See Also
       getsockopt(2), send(2), socket(2) recv(2), intro(4n), inet(4f)

																	   udp(4p)

Linux and UNIX Man Pages

udplite(7) [debian man page]

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