IP_PKTINFO(2const)                                          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)

Linux man-pages 6.17              2025-12-01                IP_PKTINFO(2const)