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udplite(7) [centos 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. 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. 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 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 3.53 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(4)							   BSD Kernel Interfaces Manual 						    UDP(4)

NAME
udp -- Internet User Datagram Protocol SYNOPSIS
#include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> int socket(AF_INET, SOCK_DGRAM, 0); DESCRIPTION
UDP is a simple, unreliable datagram protocol which is used to support the SOCK_DGRAM abstraction for the Internet protocol family. UDP sockets are connectionless, and are normally used with the sendto(2) and recvfrom(2) calls, though the connect(2) call may also be used to fix the destination for future packets (in which case the recv(2) or read(2) and send(2) or write(2) 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 (i.e., a UDP port may not be ``connected'' to a TCP port). In addition broadcast packets may be sent (assuming the underlying network supports this) by using a reserved ``broadcast address''; this address is network interface dependent. Options at the IP transport level may be used with UDP; see ip(4). ERRORS
A socket operation may fail with one of the following errors returned: [EISCONN] when trying to establish a connection on a socket which already has one, or when trying to send a datagram with the desti- nation address specified and the socket is already connected; [ENOTCONN] when trying to send a datagram, but no destination address is specified, and the socket has not been connected; [ENOBUFS] when the system runs out of memory for an internal data structure; [EADDRINUSE] when an attempt is made to create a socket with a port which has already been allocated; [EADDRNOTAVAIL] when an attempt is made to create a socket with a network address for which no network interface exists. MIB VARIABLES
The udp protocol implements a number of variables in the net.inet branch of the sysctl(3) MIB. UDPCTL_CHECKSUM (udp.checksum) Enable udp checksums (enabled by default). UDPCTL_MAXDGRAM (udp.maxdgram) Maximum outgoing UDP datagram size UDPCTL_RECVSPACE (udp.recvspace) Maximum space for incoming UDP datagrams udp.log_in_vain For all udp datagrams, to ports on which there is no socket listening, log the connection attempt (disabled by default). udp.blackhole When a datagram is received on a port where there is no socket listening, do not return an ICMP port unreachable message. (Disabled by default. See blackhole(4).) SEE ALSO
getsockopt(2), recv(2), send(2), socket(2), blackhole(4), inet(4), intro(4), ip(4) HISTORY
The udp protocol appeared in 4.2BSD. BSD
June 5, 1993 BSD

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