Thanks much Neale! It works!! :-) -nagp
On Wed, Apr 19, 2017 at 5:57 PM, Neale Ranns (nranns) <nra...@cisco.com> wrote: > Hi nagp, > > > > Sorry for the delayed response, this one slipped through the cracks. > > > > That looks like a bug to me. We should learn the ND entry from the NS’s > source address, but we don’t want a FIB entry to be generated from it. This > patch adds those functions: > > https://gerrit.fd.io/r/#/c/6264/ > > > > please let me know if it fixes your issue. If so I’ll merge. > > > > Thanks, > > neale > > > > *From: *Nagaprabhanjan Bellaru <nagp.li...@gmail.com> > *Date: *Thursday, 13 April 2017 at 14:12 > > *To: *"Neale Ranns (nranns)" <nra...@cisco.com> > *Cc: *vpp-dev <vpp-dev@lists.fd.io> > *Subject: *Re: [vpp-dev] How to send packets from control plane to a link > local IPv6 address? > > > > Hi Neale, > > In icmp6_neighbor_solicitation_or_advertisement function , a comment like > this is mentioned: > /* If src address unspecified or link local, do not learn neighbor MAC */ > > How else are we supposed to resolve link local IPv6 addresses? The > ip6_discover_neighbor_node is sending a neighbor solicitation request with > (global source ip6, link local multicast group address) - and an > advertisement is coming back with (link local source ip6, global > destination ip6) > > Thanks, > > -nagp > > > > On Thu, Apr 13, 2017 at 10:49 AM, Nagaprabhanjan Bellaru < > nagp.li...@gmail.com> wrote: > > Makes sense! Thanks much for the help!! > > Thanks, > > -nagp > > > > On Thu, Apr 13, 2017 at 12:03 AM, Neale Ranns (nranns) <nra...@cisco.com> > wrote: > > > > Hi nagp, > > > > If the neighbour is not resolved, the adjacency will be ‘incomplete’ and > yes you should use this state to choose between ip6_rewrite and > ip6_discover_neighbor (e.g. see bfd_udp_input()*) > > > > There is a subtle difference between a glean and an incomplete adjacency: > > - An incomplete adjacency is represents an explicit next-hop, > i.e. one for which we know the IP address, but do not yet know the MAC > address. When packets encounter an incomplete address an ARP/ND packet is > sent to discover the next-hop address the adjacency represents. When the > MAC address is discovered, this adjacency object instance transitions to > the ‘complete’ state. > > - A glean adjacency represents the whole subnet, i.e. given ‘set > int ip addr XXX 10.10.10.10/24’ the glean adjacency is used for traffic > matching 10.10.10.0/24. If packets encounter a glean adjacency then an > ARP/ND packet is sent to discover that packet’s destination IP address. > > > > These functions are implemented in two different VLIB nodes (e.g. ip4_arp > and ipv4_glean respectively). > > When you find the adjacency via ‘adj_nbr_add_or_lock’ you will never get a > glean adj, you’ll only get [in]complete ones. > > > > Regards, > > Neale > > > > *there are other ways to do this if you have an object you can ‘dpo_stack’ > and re-stack when the adj changes state. There are various examples of > features stacking on a fib_entry (e.g. LISP and VXALN), but not on an > adjacency – but the principle is the same. > > > > *From: *Nagaprabhanjan Bellaru <nagp.li...@gmail.com> > *Date: *Wednesday, 12 April 2017 at 18:30 > > > *To: *"Neale Ranns (nranns)" <nra...@cisco.com> > *Cc: *vpp-dev <vpp-dev@lists.fd.io> > *Subject: *Re: [vpp-dev] How to send packets from control plane to a link > local IPv6 address? > > > > Thanks! One small question - if the neighbor is not resolved yet, will the > lookup yield a glean adjacency? If that is the case, depending on the type > of the result, I should punt the packet to either ip6_rewrite or > ip6_discover_neighbor? > > Thanks, > > -nagp > > > > On Wed, Apr 12, 2017 at 10:40 PM, Neale Ranns (nranns) <nra...@cisco.com> > wrote: > > > > Hi nagp, > > > > I do indeed mean the result of a ip6_fib_table_lookup. The goal of a > lookup is ultimately to find the adjacency to use (and thus eventually get > to ip6_rwrite node). Since you know the adjacency’s full description, it is > more efficient to retrieve it directly from the adjacency data-base and go > directly to ip6_rewrite. > > > > As you say, if one where to do a lookup for a link-local address in the > FIB, then one should use the interface as part of the key, i.e. a /160 > lookup, or perhaps in a per-interface link-local address only ‘FIB’. But > VPP has no such function. The adjacency data-base serves this purpose*. > > > > Regards, > > Neale > > > > *if you are using this in the data-plane though, we should consider > alternatives. > > > > *From: *Nagaprabhanjan Bellaru <nagp.li...@gmail.com> > *Date: *Wednesday, 12 April 2017 at 14:04 > *To: *"Neale Ranns (nranns)" <nra...@cisco.com> > *Cc: *vpp-dev <vpp-dev@lists.fd.io> > *Subject: *Re: [vpp-dev] How to send packets from control plane to a link > local IPv6 address? > > > > Thanks Neale! > > By the "result of the lookup" do you mean looking up through > ip6_fib_table_lookup? I don't this lookup taking a interface also (for the > link local case). Please correct my understanding. > > Thanks, > > -nagp > > > > On Wed, Apr 12, 2017 at 4:30 PM, Neale Ranns (nranns) <nra...@cisco.com> > wrote: > > Hi nagp, > > > > If you know the destination address is link local and you know on which > interface, then the result of the lookup will result in the adjacency for > that link-local address on that interface, i.e. the adjacency you would get > back from; > > adj_index_t ai = adj_nbr_add_or_lock(FIB_PROTOCOL_IP6, VNET_LINK_IP6, > <ll_add>, <interface>); > > > > now you have the adjacency, the lookup is not required, so you can send > the packet directly to ip6_rewrite/ip6_discover_neighbor. There is an > example of this in the BFD code (see bfd_udp_input()). > > > > Hth, > > neale > > > > *From: *<vpp-dev-boun...@lists.fd.io> on behalf of Nagaprabhanjan Bellaru > <nagp.li...@gmail.com> > *Date: *Wednesday, 12 April 2017 at 11:27 > *To: *vpp-dev <vpp-dev@lists.fd.io> > *Subject: *[vpp-dev] How to send packets from control plane to a link > local IPv6 address? > > > > Hi, > > How can I send packets to a link local IPv6 address? I know the interface > on which the packet has to be sent, but when I enqueue the packet to > "ip6_lookup" node, how can I encode the interface such that the neighor > resolution happens on that interface and the packet gets transmitted? > > Thanks, > > -nagp > > > > > > > > > >
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