Hi Matt, I have no explanation for why adj_index[VLIB_RX] is set to the same value as the TX, AFAICT it’s been that way since time immemorial 😉 I think we should change that logic to RX=TX; TX=lbi. I don’t see anything in the code that relies on RX being set to the TX. In that case the RX will be the receive DPO which has the sw_if_index associated with the for-us FIB entry.
Is your plugin running as a for-us feature? That’s good if you want to see all the for-us packets. If you want per-prefix for-us you might consider a interposing your own DPO in that prefixes output chain. See the interposed gbp_policy_dpo_t for an example. Regards, neale De : "Dave Barach (dbarach)" <dbar...@cisco.com> Date : vendredi 14 juin 2019 à 20:30 À : "mgsm...@netgate.com" <mgsm...@netgate.com>, "Neale Ranns (nranns)" <nra...@cisco.com> Objet : Re: [vpp-dev] identifying packets sent to a loopback address This is a Neale Ranns question. Looping him in... HTH... Dave ________________________________ From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> on behalf of Matthew Smith via Lists.Fd.Io <mgsmith=netgate....@lists.fd.io> Sent: Friday, June 14, 2019 1:52 PM To: vpp-dev Cc: vpp-dev@lists.fd.io Subject: [vpp-dev] identifying packets sent to a loopback address Hi, I have a plugin node in which I want to process some received packets. When a packet is destined to an IP address that is configured on a loopback interface, I want to be able to lookup some data based on the sw_if_index of the loopback interface. Packets that are sent to the loopback address are received on hardware interfaces, so I cannot look at sw_if_index[VLIB_RX] in the vnet buffer opaque data to find out that the packet destination address belongs to a loopback. I was hoping that ip.adj_index[VLIB_TX] would contain data that would help me do what I'm trying to do, but that does not seem to be the case. In ip4-lookup, a FIB entry is found which matches the loopback address. The index of the adjacency for the path is stored in ip.adj_index[VLIB_TX]. But the stored value is subsequently overwritten in ip4-local during the call to ip4_local_check_src(). That function does a lookup on the source IP address and overwrites both ip.adj_index[VLIB_RX] and ip.adj_index[VLIB_TX] with the index retrieved by the lookup. I can work around this in my plugin code if I need to but it would be nice to be able to use the adjacency data that was retrieved by ip4-lookup. Would it break anything if ip4_local_check_src() only updates ip.adj_index[VLIB_RX] and leaves the contents of ip.adj_index[VLIB_TX] intact? Thanks, -Matt
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#13295): https://lists.fd.io/g/vpp-dev/message/13295 Mute This Topic: https://lists.fd.io/mt/32066650/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
