HP-UX Reference (11i v3 07/02) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

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IPv6(7P) IPv6(7P)

option value speciﬁed is used as the hop limit for all subsequent unicast

packets sent via that socket. Valid values are in the range 0-255 (both

inclusive) and the default value is 64. For example,

int hoplimit = 50;

setsockopt(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS,

&hoplimit, sizeof(hoplimit));

This option can be used with getsockopt()

(see getsockopt(2)) to deter-

mine the hop limit value the system will use for subsequent unicast packets

sent via that socket.

IPV6_MULTICAST_HOPS

(integer) Set or get the hop limit used in outgoing multicast packets.

When this option is set, the new option value speciﬁed is used as the hop

limit for all subsequent multicast packets sent via that socket. Valid values

are in the range 0-255 (both inclusive) and the default value is 1.

IPV6_MULTICAST_IF

(integer) Sets the interface to use for outgoing multicast packets. The

option value is the index of the selected outgoing interface. For example,

unsigned int index;

index = if_nametoindex("lan0");

setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_IF,

&index, sizeof(index));

IPV6_MULTICAST_LOOP

(boolean) Enables or disables loopback in the IP layer for multicast

datagrams sent through this socket. The value of the variable pointed to by

optval is zero (disable) or non-zero (enable). Default: enabled.

IPV6_JOIN_GROUP (

struct ipv6_mreq ) Join a multicast group on a speciﬁed local inter-

face. The IPv6 multicast address of the group to join and the index of the

interface on which to join should be speciﬁed using

struct ipv6_mreq

which is deﬁned in <netinet/in6.h

> as:

struct ipv6_mreq {

struct in6_addr ipv6mr_multiaddr;

/* IPv6 multicast addr */

unsigned int ipv6mr_interface;

/* interface index */

};

If the interface index is speciﬁed as 0 then the default multicast interface is

used.

IPV6_LEAVE_GROUP

(struct ipv6_mreq) Leave a multicast group on a speciﬁed local inter-

face. The IPv6 multicast address of the group to leave and the interface

index should be speciﬁed using

struct ipv6_mreq. The interface

index should match the index used while joining the group. Set index to 0,

to specify default interface.

IPV6_CHECKSUM (integer) When this option is set, kernel computes the checksum for out-

bound packets and veriﬁes checksum on inbound packets. The option value

is the byte offset of the checksum location in the user data. This option is

not valid for IPPROTO_ICMPV6 since checksum computation is manda-

tory for IPPROTO_ICMPV6. The default value is -1 (checksums not com-

puted nor veriﬁed for protocols other than IPPROTO_ICMPV6).

IPV6_RECVPKTINFO (boolean) When this option is enabled, PKTINFO (destination IPv6

address and the arriving interface index) is returned as ancillary data by

recvmsg(). (See recvmsg (2)). The information is returned in struct

HP-UX 11i Version 3: February 2007 − 2 − Hewlett-Packard Company 65