udplite(4) [freebsd man page]

UDPLITE(4)						   BSD Kernel Interfaces Manual 						UDPLITE(4)

NAME

     udplite -- Lightweight User Datagram Protocol

SYNOPSIS

     #include <sys/types.h>
     #include <sys/socket.h>
     #include <netinet/udplite.h>

     int
     socket(AF_INET, SOCK_DGRAM, IPPROTO_UDPLITE);

DESCRIPTION

     The UDP-Lite protocol provides a partial checksum which allows corrupted packets to be transmitted to the receiving application.  This has
     advantages for some types of multimedia transport that may be able to make use of slightly damaged datagrams, rather than having them dis-
     carded by lower-layer protocols.

     UDP-Lite supports a number of socket options which can be set with setsockopt(2) and tested with getsockopt(2):

     UDPLITE_SEND_CSCOV  This option sets the sender checksum coverage.  A value of zero indicates that all sent packets will have full checksum
			 coverage.  A value of 8 to 65535 limits the checksum coverage of all sent packets to the value given.

     UDPLITE_RECV_CSCOV  This option is the receiver-side analogue.  A value of zero instructs the kernel to drop all received packets not having
			 full checksum coverage.  A value of 8 to 65535 instructs the kernel to drop all received packets with a partial checksum
			 coverage smaller than the value specified.

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.

SEE ALSO

     getsockopt(2), recv(2), send(2), socket(2)

BSD
								  October 1, 2014							       BSD

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).

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).)

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.

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