IPV6_ROUTER_ALERT(2const) — Linux manual page

IPV6_ROUTER_ALERT(2const)                       IPV6_ROUTER_ALERT(2const)

NAME         top

       IPV6_ROUTER_ALERT - pass forwarded packets containing a router
       alert hop-by-hop to this socket

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

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

       int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_ROUTER_ALERT,
                      const int *val, sizeof(int));

DESCRIPTION         top

       Pass forwarded packets containing a router alert hop-by-hop option
       to this socket.

       Allowed only for SOCK_RAW sockets.

       The tapped packets are not forwarded by the kernel, it is the
       user's responsibility to send them out again.

       A positive integer indicates a router alert option value to
       intercept.  Packets carrying a router alert option with a value
       field containing this integer will be delivered to the socket.  A
       negative integer disables delivery of packets with router alert
       options to this socket.

ERRORS         top

       See IPPROTO_IPV6(2const).  See setsockopt(2).  See ipv6(7).

SEE ALSO         top

       IPPROTO_IPV6(2const), setsockopt(2), cmsg(3), ipv6(7)

COLOPHON         top

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Linux man-pages 6.18            2025-12-02      IPV6_ROUTER_ALERT(2const)

Pages that refer to this page: IPPROTO_IPV6(2const)

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