IP_PKTINFO(2const)

NAME
IP_PKTINFO - information about the incoming packet

LIBRARY
Standard C library (libc, -lc)

SYNOPSIS
#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>

int setsockopt(int sockfd, IPPROTO_IP, IP_PKTINFO,
               const int *enable, sizeof(int));

DESCRIPTION
Pass an IP_PKTINFO ancillary message that contains a in_pktinfo(2type) structure that supplies some information about the incoming packet. This works only for datagram oriented sockets.

The argument is a flag that tells the socket whether the IP_PKTINFO message should be passed or not.

The message itself can be sent/retrieved only as a control message with a packet using recvmsg(2) or sendmsg(2).

Not supported for SOCK_STREAM sockets.

ERRORS
See IPPROTO_IP(2const). See setsockopt(2). See ip(7).

VERSIONS
Some BSD sockets implementations provide IP_RCVDSTADDR and IP_RECVIF socket options to get the destination address and the interface of received datagrams. Linux has the more general IP_PKTINFO for the same task.

STANDARDS
Linux.

HISTORY
Linux 2.2.

SEE ALSO
in_pktinfo(2const), IPPROTO_IP(2const), setsockopt(2), ip(7)