Section: Linux Programmer's Manual (7)
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udplite - Lightweight User Datagram Protocol
sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDPLITE);
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
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
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
is, it shares the same API and API behavior, and in addition
offers two socket options to control the checksum coverage.
UDP-Litev4 uses the
address format described in
UDP-Litev6 uses the
address format described in
To set or get a UDP-Lite socket option, call
to read or
to write the option with the option level argument set to
In addition, all
socket options are valid on a UDP-Lite socket.
for more information.
The following two options are specific to UDP-Lite.
This option sets the sender checksum coverage and takes an
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
This is the receiver-side analogue and uses the same argument format
and value range as
This option is not required to enable traffic with partial checksum
Its function is that of a traffic filter: when enabled, it
instructs the kernel to drop all packets which have a coverage
than the specified coverage value.
When the value of
exceeds the actual packet coverage, incoming packets are silently dropped,
but may generate a warning message in the system log.
All errors documented for
may be returned.
UDP-Lite does not add further errors.
- basic UDP-Litev4 statistics counters.
- basic UDP-Litev6 statistics counters.
UDP-Litev4/v6 first appeared in Linux 2.6.20.
Where glibc support is missing, the following definitions are needed:
#define IPPROTO_UDPLITE 136
#define UDPLITE_SEND_CSCOV 10
#define UDPLITE_RECV_CSCOV 11
RFC 3828 for the Lightweight User Datagram Protocol (UDP-Lite).
in the Linux kernel source tree
This page is part of release 3.74 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
- Address format
- Socket options
- SEE ALSO