To answer my own question :-) These strange link local addresses are explained in the developers handbook section 8.1.1.3 and are called embedded link local addresses. These are not standard IPv6 addresses, but a way to encode the interface index (aka zone index) into the IPv6 address. This must be undone by the user program before using these addresses.
harti -----Original Message----- From: [email protected] on behalf of [email protected] Sent: Wed 11/25/2009 1:15 PM To: [email protected] Subject: Need help on IPv6 prefixes and interface addresses Hi all, I try to make bsnmpd IPv6 aware and need some help here. I've set up a small IPv6 network for testing between a couple of VMs. For IPv6 interface addresses there are two tables: ipAddressPrefix table and ipAddressTable (containing pointers to the prefix table). Now I see something on my system I cannot grasp. ndp -pn gives me: 2001:638:101:ff::/64 if=le0 flags=LO vltime=infinity, pltime=infinity, expire=Never, ref=1 No advertising router fe80::%le0/64 if=le0 flags=LAO vltime=infinity, pltime=infinity, expire=Never, ref=0 No advertising router fe80::%lo0/64 if=lo0 flags=LAO vltime=infinity, pltime=infinity, expire=Never, ref=0 No advertising router ifconfig -a inet6 gives: le0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=8<VLAN_MTU> inet6 fe80::20c:29ff:fe90:dd1b%le0 prefixlen 64 scopeid 0x1 inet6 2001:638:101:ff::8:ffff prefixlen 64 lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 options=3<RXCSUM,TXCSUM> inet6 ::1 prefixlen 128 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 So far, so nice. When I ask for the interface addresses via sysctl([0, NET_RT_IFLIST, 0], ...) I get strange RTM_NEWADDR messages: msglen=76 version=5 type=RTM_NEWADDR flags=0 index=1 metric=0 netmask=INET6,28,{0,0,ffff:ffff:ffff:ffff::,0} ifa=INET6,28,{0,0,fe80:1::20c:29ff:fe90:dd1b,0} Which means a prefix of fe80:1::/64 instead of fe80::%le0/64. Note, the :1: there and note the zero missing scope_id (the last 0 inside the {}). Same for lo0: msglen=80 version=5 type=RTM_NEWADDR flags=0 index=2 metric=0 netmask=INET6,28,{0,0,ffff:ffff:ffff:ffff::,0} ifa=INET6,28,{0,0,fe80:2::1,0} brd=UNSPEC,0,{} So my questions: - are the routing message really that inconsistent and broken? Or do I read them somehow incorrect? - is it possible to rely on the prefix table? In other words: Does *each* prefix used in a INET6 interface address appear in the prefix list? harti _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[email protected]"
