IPV6_RTHDR(2const) IPV6_RTHDR(2const)

IPV6_RTHDR, IPV6_AUTHHDR, IPV6_DSTOPTS, IPV6_HOPOPTS, IPV6_FLOWINFO, IPV6_HOPLIMIT - set the delivery of control messages for incoming datagrams containing extension headers

Standard C library (libc-lc)

#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_RTHDR,
               const int *enable, sizeof(int));
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_AUTHHDR,
               const int *enable, sizeof(int));
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_DSTOPTS,
               const int *enable, sizeof(int));
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_HOPOPTS,
               const int *enable, sizeof(int));
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_FLOWINFO,
               const int *enable, sizeof(int));
int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_HOPLIMIT,
               const int *enable, sizeof(int));

Set delivery of control messages for incoming datagrams containing extension headers from the received packet.

delivers the routing header.
delivers the authentication header.
delivers the destination options.
delivers the hop options.
delivers an integer containing the flow ID.
delivers an integer containing the hop count of the packet.

The control messages have the same type as the socket option.

All these header options can also be set for outgoing packets by putting the appropriate control message into the control buffer of sendmsg(2).

Allowed only for SOCK_DGRAM or SOCK_RAW sockets.

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

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

2025-12-02 Linux man-pages 6.17