tunnel: Do not carry source port from a previous tunnel.

If a packet is received from a UDP tunnel, it has a source port
populated in the tunnel metadata.  This field cannot be read or
changed with OpenFlow or the tunnel configuration.  However, while
sending this packet to a different tunnel, the value remains in
the metadata and is being sent to the datapath to use as a source
port for this new tunnel.  Tunnel implementations largely ignore
this value, and it is a random value from a different tunnel
anyway.

Clear it while sending to a different tunnel, so the unnecessary
information is not being passed to the datapath.  This additionally
allows traffic from one tunnel to anther to be offloaded to TC,
as TC doesn't allow setting the source port at all.

Tested-by: Vladislav Odintsov <[email protected]>
Acked-by: Eelco Chaudron <[email protected]>
Signed-off-by: Ilya Maximets <[email protected]>

ofproto/tunnel.c

@@ -432,6 +432,7 @@ tnl_port_send(const struct ofport_dpif *ofport, struct flow *flow,
             flow->tunnel.ipv6_dst = in6addr_any;
         }
     }
+    flow->tunnel.tp_src = 0; /* Do not carry from a previous tunnel. */
     flow->tunnel.tp_dst = cfg->dst_port;
     if (!cfg->out_key_flow) {
         flow->tunnel.tun_id = cfg->out_key;

tests/tunnel.at

@@ -333,6 +333,50 @@ set(tunnel(tun_id=0x5,dst=4.4.4.4,ttl=64,flags(df|key))),1
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([tunnel - set_tunnel VXLAN])
+OVS_VSWITCHD_START([dnl
+    add-port br0 p1 -- set Interface p1 type=vxlan options:key=flow \
+        options:remote_ip=1.1.1.1 ofport_request=1 \
+    -- add-port br0 p2 -- set Interface p2 type=vxlan options:key=flow \
+        options:remote_ip=2.2.2.2 ofport_request=2 \
+    -- add-port br0 p3 -- set Interface p3 type=vxlan options:key=flow \
+        options:remote_ip=3.3.3.3 ofport_request=3 \
+    -- add-port br0 p4 -- set Interface p4 type=vxlan options:key=flow \
+        options:remote_ip=4.4.4.4 ofport_request=4])
+AT_DATA([flows.txt], [dnl
+actions=set_tunnel:1,output:1,set_tunnel:2,output:2,set_tunnel:3,output:3,set_tunnel:5,output:4
+])
+
+OVS_VSWITCHD_DISABLE_TUNNEL_PUSH_POP
+AT_CHECK([ovs-ofctl add-flows br0 flows.txt])
+
+AT_CHECK([ovs-appctl dpif/show | tail -n +3], [0], [dnl
+    br0 65534/100: (dummy-internal)
+    p1 1/4789: (vxlan: key=flow, remote_ip=1.1.1.1)
+    p2 2/4789: (vxlan: key=flow, remote_ip=2.2.2.2)
+    p3 3/4789: (vxlan: key=flow, remote_ip=3.3.3.3)
+    p4 4/4789: (vxlan: key=flow, remote_ip=4.4.4.4)
+])
+
+AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 'in_port(100),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=1,tos=0,ttl=128,frag=no),icmp(type=8,code=0)'], [0], [stdout])
+AT_CHECK([tail -1 stdout], [0], [Datapath actions: dnl
+set(tunnel(tun_id=0x1,dst=1.1.1.1,ttl=64,tp_dst=4789,flags(df|key))),4789,dnl
+set(tunnel(tun_id=0x2,dst=2.2.2.2,ttl=64,tp_dst=4789,flags(df|key))),4789,dnl
+set(tunnel(tun_id=0x3,dst=3.3.3.3,ttl=64,tp_dst=4789,flags(df|key))),4789,dnl
+set(tunnel(tun_id=0x5,dst=4.4.4.4,ttl=64,tp_dst=4789,flags(df|key))),4789
+])
+
+dnl With pre-existing tunnel metadata.
+AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 'tunnel(tun_id=0x1,src=1.1.1.1,dst=5.5.5.5,tp_src=12345,tp_dst=4789,ttl=64,flags(key)),in_port(4789),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=1,tos=0,ttl=128,frag=no),icmp(type=8,code=0)'], [0], [stdout])
+AT_CHECK([tail -1 stdout], [0], [Datapath actions: dnl
+set(tunnel(tun_id=0x2,dst=2.2.2.2,ttl=64,tp_dst=4789,flags(df|key))),4789,dnl
+set(tunnel(tun_id=0x3,dst=3.3.3.3,ttl=64,tp_dst=4789,flags(df|key))),4789,dnl
+set(tunnel(tun_id=0x5,dst=4.4.4.4,ttl=64,tp_dst=4789,flags(df|key))),4789
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_SETUP([tunnel - key])
 OVS_VSWITCHD_START([dnl
     add-port br0 p1 -- set Interface p1 type=gre options:key=1 \