taintgobgprib

This code is to reproduce a bug in the current version of GoBGP (1.29) as its RIB entry can be tainted by repetitive GetRib() requests.

Update

Shortly after I reported the bug as issue 1614, they nailed and fixed it with cda7c44.

What it does

Generate a stream of GetRib() requests to a local GoBGP daemon until it receives an incorrect response.

How to reproduce the bug

• Install GoBGP and start the daemon.

gobgpd --cpus=2 &

• Activate the daemon with an arbitrary asn, router-id, and port number.

gobgp global as 65001 router-id 10.0.0.1 listen-port 12345

• Add ipv4-unicast rib entries like so:

gobgp global rib add -a ipv4 172.16.0.0/12 nexthop 10.0.0.1
gobgp global rib add -a ipv4 192.168.0.0/16 nexthop 10.0.0.1

• Make sure they're properly installed.

gobgp global rib
   Network              Next Hop             AS_PATH              Age        Attrs
*> 172.16.0.0/12        10.0.0.1                                  00:00:03   [{Origin: ?}]
*> 192.168.0.0/16       10.0.0.1                                  00:00:03   [{Origin: ?}]

• Start this program with one or more IP addresses matching the previously installed rib as arguments.

GOMAXPROCS=8 go run taintrib.go 172.16.0.1 192.168.1.1

• Sit back and wait until it stops like so:

2018/03/15 15:35:05 ERROR: search request #8318360 [172.16.0.1 192.168.1.1], result [172.16.0.0/12 0.168.0.0/16]
exit status 1

• See one of the entries is now tainted.

gobgp global rib
   Network              Next Hop             AS_PATH              Age        Attrs
*> 172.16.0.0/12        10.0.0.1                                  00:14:12   [{Origin: ?}]
*> 0.168.0.0/16         10.0.0.1                                  00:14:12   [{Origin: ?}]

Usage notes

• The number of requests required to hit the bug varies each time. Sometimes it takes less than 1M, other times it's more than 8M like the above (8318360).

• The fan-out logic of this code is pretty much stolen from balance.go, but the program exits if all workers are occupied.

• In case it happens, you need to tweak values of the first three constants, GOMAXPROCS env, and also --cpus option for gobgpd.