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authorNeale Ranns <nranns@cisco.com>2018-12-06 13:46:49 +0000
committerDamjan Marion <dmarion@me.com>2018-12-07 15:09:37 +0000
commit521a8d7df423a0b5aaf259d49ca9230705bc25ee (patch)
tree12559229002f31b289adb15460b967a3d10900f3 /test/test_gre.py
parentab86f86e7c29393fa1da81b5f86296bd5fcb7420 (diff)
FIB recusrion loop checks traverse midchain adjacencies
if a tunnel's destination address is reachable through the tunnel (see example config belwo) then search for and detect a recursion loop and don't stack the adjacency. Otherwise this results in a nasty surprise. DBGvpp# loop cre DBGvpp# set int state loop0 up DBGvpp# set int ip addr loop0 10.0.0.1/24 DBGvpp# create gre tunnel src 10.0.0.1 dst 1.1.1.1 DBGvpp# set int state gre0 up DBGvpp# set int unnum gre0 use loop0 DBGvpp# ip route 1.1.1.1/32 via gre0 DBGvpp# sh ip fib 1.1.1.1 ipv4-VRF:0, fib_index:0, flow hash:[src dst sport dport proto ] locks:[src:plugin-hi:2, src:default-route:1, ] 1.1.1.1/32 fib:0 index:11 locks:4 <<< this is entry #11 src:CLI refs:1 entry-flags:attached, src-flags:added,contributing,active, path-list:[14] locks:2 flags:shared,looped, uPRF-list:12 len:1 itfs:[2, ] path:[14] pl-index:14 ip4 weight=1 pref=0 attached-nexthop: oper-flags:recursive-loop,resolved, cfg-flags:attached, 1.1.1.1 gre0 (p2p) [@0]: ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: <<<< and the midchain forwards via entry #11 [@2]: dpo-drop ip4 src:recursive-resolution refs:1 src-flags:added, cover:-1 forwarding: unicast-ip4-chain [@0]: dpo-load-balance: [proto:ip4 index:13 buckets:1 uRPF:12 to:[0:0]] [0] [@6]: ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: [@2]: dpo-drop ip4 DBGvpp# sh adj 1 [@1] ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: [@2]: dpo-drop ip4 flags:midchain-ip-stack midchain-looped <<<<< this is a loop counts:[0:0] locks:4 delegates: children: {path:14} Change-Id: I39b82bd1ea439be4611c88b130d40289fa0c1b59 Signed-off-by: Neale Ranns <nranns@cisco.com>
Diffstat (limited to 'test/test_gre.py')
-rw-r--r--test/test_gre.py61
1 files changed, 61 insertions, 0 deletions
diff --git a/test/test_gre.py b/test/test_gre.py
index eed3d8b2c6f..dd7b8bc6b8f 100644
--- a/test/test_gre.py
+++ b/test/test_gre.py
@@ -867,6 +867,67 @@ class TestGRE(VppTestCase):
route_tun1_dst.add_vpp_config()
route_tun2_dst.add_vpp_config()
+ def test_gre_loop(self):
+ """ GRE tunnel loop Tests """
+
+ #
+ # Create an L3 GRE tunnel.
+ # - set it admin up
+ # - assign an IP Addres
+ #
+ gre_if = VppGreInterface(self,
+ self.pg0.local_ip4,
+ "1.1.1.2")
+ gre_if.add_vpp_config()
+ gre_if.admin_up()
+ gre_if.config_ip4()
+
+ #
+ # add a route to the tunnel's destination that points
+ # through the tunnel, hence forming a loop in the forwarding
+ # graph
+ #
+ route_dst = VppIpRoute(self, "1.1.1.2", 32,
+ [VppRoutePath("0.0.0.0",
+ gre_if.sw_if_index)])
+ route_dst.add_vpp_config()
+
+ #
+ # packets to the tunnels destination should be dropped
+ #
+ tx = self.create_stream_ip4(self.pg0, "1.1.1.1", "1.1.1.2")
+ self.send_and_assert_no_replies(self.pg2, tx)
+
+ self.logger.info(self.vapi.ppcli("sh adj 7"))
+
+ #
+ # break the loop
+ #
+ route_dst.modify([VppRoutePath(self.pg1.remote_ip4,
+ self.pg1.sw_if_index)])
+ route_dst.add_vpp_config()
+
+ rx = self.send_and_expect(self.pg0, tx, self.pg1)
+
+ #
+ # a good route throught the tunnel to check it restacked
+ #
+ route_via_tun_2 = VppIpRoute(self, "2.2.2.2", 32,
+ [VppRoutePath("0.0.0.0",
+ gre_if.sw_if_index)])
+ route_via_tun_2.add_vpp_config()
+
+ tx = self.create_stream_ip4(self.pg0, "2.2.2.3", "2.2.2.2")
+ rx = self.send_and_expect(self.pg0, tx, self.pg1)
+ self.verify_tunneled_4o4(self.pg1, rx, tx,
+ self.pg0.local_ip4, "1.1.1.2")
+
+ #
+ # cleanup
+ #
+ route_via_tun_2.remove_vpp_config()
+ gre_if.remove_vpp_config()
+
if __name__ == '__main__':
unittest.main(testRunner=VppTestRunner)