[VPP-1668] FIB should not install .0 for an address as drop route

[vvalderrv]

Description

Currently if one adds an address to an interface, a drop route for the first address (.0) in the connected network is added as a drop route. That's too strict.

set interface ip address loop0 11.11.11.11/31

Results in:

11.11.11.10/32

  unicast-ip4-chain

  [@0]: dpo-load-balance: [proto:ip4 index:13 buckets:1 uRPF:14 to:[0:0]]

    [0] [@0]: dpo-drop ip4

11.11.11.11/32

  unicast-ip4-chain

  [@0]: dpo-load-balance: [proto:ip4 index:14 buckets:1 uRPF:15 to:[0:0]]

    [0] [@2]: dpo-receive: 11.11.11.11 on loop0

Assignee

Neale Ranns

Reporter

Ole Trøan

Comments

• nranns (Sat, 11 May 2019 14:08:46 +0000): if the interface is up, then the .0 address is not via drop, it's an adjacency to the .0 peer.
• otroan (Sat, 11 May 2019 13:08:48 +0000): Point being?
• nranns (Sat, 11 May 2019 09:42:31 +0000): set int state loop0 up

results in:

DBGvpp# sh ip fib 11.11.11.10

ipv4-VRF:0, fib_index:0, flow hash:[src dst sport dport proto ] locks:[src:plugin-hi:2, src:default-route:1, ]

11.11.11.10/32 fib:0 index:7 locks:2

  src:interface refs:1 entry-flags:attached, src-flags:added,contributing,active, cover:-1

    path-list:[12] locks:2 uPRF-list:7 len:1 itfs:[1, ]

      path:[12] pl-index:12 ip4 weight=1 pref=0 attached-nexthop:  oper-flags:resolved,

        11.11.11.10 loop0

      [@0]: arp-ipv4: via 11.11.11.10 loop0

forwarding:   unicast-ip4-chain

  [@0]: dpo-load-balance: [proto:ip4 index:9 buckets:1 uRPF:7 to:[0:0]]

    [0] [@3]: arp-ipv4: via 11.11.11.10 loop0

Original issue: https://jira.fd.io/browse/VPP-1668