ip6.7p (2010 09)

IPv6(7P) IPv6(7P)

IPV6_USE_MIN_MTU

(integer) Used to control the behavior of path MTU discovery.

1 speciﬁes that path MTU discovery will be disabled and packets will

be sent using the minimum MTU.

0 speciﬁes that path MTU discovery will be performed.

-1 speciﬁes that path MTU discovery will be performed for unicast des-

tinations but not for multicast destinations, and packets to multicast

destinations will be sent using the minimum MTU.

Values other than -1, 0, and 1 are not valid.

IPV6_DONTFRAG (boolean) Used to disable the automatic insertion of fragment headers.

This option is not supported on SOCK_STREAM sockets. By default this

option is disabled.

IPv6 uses the enhanced version of ICMP called ICMPv6 to report errors encountered in processing pack-

ets and for diagnostic purposes (like ping). ICMPv6 is an integral part of IPv6 and has a next header

value of 58.

While some of the options and the associated structures are deﬁned in

, applications

are not required to include this header ﬁle explicitly, it is automatically included by

<netinet/in.h>.

ERRORS

One of the following errors may be returned when a socket operation fails.

[EADDRINUSE] The speciﬁed multicast group has been joined already.

[EADDRNOTAVAIL] The speciﬁed IPv6 address is not a local interface address or there is no

route for the speciﬁed multicast address or the speciﬁed multicast group

has not been joined.

[EAFNOSUPPORT] The address family is not supported.

[EINVAL] The parameter ’level’ is not

IPPROTO_IPV6,oroptval is the NULL

address, or the speciﬁed multicast address is not valid, or the speciﬁed

source address is not valid, or the speciﬁed interface index is not valid, or

the option is not valid for the current ﬁlter mode, or the speciﬁed hop limit

is not in the range 0 <= x<= 255, or the speciﬁed trafﬁc class is not in the

range -1 <= x <= 255.

[ENOBUFS] Insufﬁcient memory is available for internal system data structures, or the

number of source addresses exceeds the maximum number of sources

allowed, as determined by the

ndd tunable parameters

ip_ipc_mcast_maxsrc

and ip_igmp_maxsrc (for IPv4), or

ip6_ipc_mcast_maxsrc

and ip6_mld_maxsrc (for IPv6).

[ENOPROTOOPT] The parameter optname is not a valid socket option for the

IPPROTO_IPV6 level.

[EOPNOTSUPP] The option is not supported for the socket type.

AUTHOR

The socket interfaces to IP were developed by the University of California, Berkeley.