On 6 Apr 2021, at 10:27, Martin Varghese wrote:

On Thu, Apr 01, 2021 at 11:32:06AM +0200, Eelco Chaudron wrote:


On 1 Apr 2021, at 11:28, Martin Varghese wrote:

On Thu, Apr 01, 2021 at 11:17:14AM +0200, Eelco Chaudron wrote:


On 1 Apr 2021, at 11:09, Martin Varghese wrote:

On Thu, Apr 01, 2021 at 10:54:42AM +0200, Eelco Chaudron wrote:


On 1 Apr 2021, at 10:35, Martin Varghese wrote:

On Thu, Apr 01, 2021 at 08:59:27AM +0200, Eelco Chaudron wrote:


On 1 Apr 2021, at 6:10, Martin Varghese wrote:

On Wed, Mar 31, 2021 at 03:59:40PM +0200, Eelco Chaudron wrote:


On 26 Mar 2021, at 7:21, Martin Varghese wrote:

From: Martin Varghese <[email protected]>

The encap & decap actions are extended to support MPLS
packet type.
Encap & decap actions adds and removes MPLS
header at start of the
packet.

Hi Martin,

I’m trying to do some real-life testing, and
I’m running into
issues. This
might be me setting it up wrongly but just
wanting to confirm…

I’m sending an MPLS packet that contains an ARP packet into a
physical port.
This is the packet:

Frame 4: 64 bytes on wire (512 bits), 64 bytes
captured (512 bits)
    Encapsulation type: Ethernet (1)
    [Protocols in frame: eth:ethertype:mpls:data]
Ethernet II, Src: 00:00:00_00:00:01 (00:00:00:00:00:01), Dst:
00:00:00_00:00:02 (00:00:00:00:00:02)
    Destination: 00:00:00_00:00:02 (00:00:00:00:00:02)
        Address: 00:00:00_00:00:02 (00:00:00:00:00:02)
.... ..0. .... .... .... .... = LG bit: Globally unique
address
(factory default)
        .... ...0 .... .... .... .... = IG bit:
Individual address
(unicast)
    Source: 00:00:00_00:00:01 (00:00:00:00:00:01)
        Address: 00:00:00_00:00:01 (00:00:00:00:00:01)
.... ..0. .... .... .... .... = LG bit: Globally unique
address
(factory default)
        .... ...0 .... .... .... .... = IG bit:
Individual address
(unicast)
    Type: MPLS label switched packet (0x8847)
MultiProtocol Label Switching Header, Label: 100, Exp: 0, S:
1, TTL:
64
    0000 0000 0000 0110 0100 .... .... .... = MPLS Label: 100
.... .... .... .... .... 000. .... .... = MPLS Experimental
Bits: 0
    .... .... .... .... .... ...1 .... .... = MPLS
Bottom Of Label
Stack: 1
    .... .... .... .... .... .... 0100 0000 = MPLS TTL: 64
Data (46 bytes)

0000  ff ff ff ff ff ff 52 54 00 88 51 38 08 06 00 01
......RT..Q8....
0010  08 00 06 04 00 01 52 54 00 88 51 38 01 01 01 65
......RT..Q8...e
0020  00 00 00 00 00 00 01 01 01 64 27 98 a0 47
.........d'..G
    Data:
ffffffffffff525400885138080600010800060400015254008851380101016500000000?


I’m trying to use the following rules:

  ovs-ofctl del-flows ovs_pvp_br0
  ovs-ofctl add-flow -O OpenFlow13 ovs_pvp_br0
"priority=100,dl_type=0x8847,mpls_label=100
actions=decap(),decap(packet_type(ns=0,type=0x806)),resubmit(,3)"
  ovs-ofctl add-flow -O OpenFlow13 ovs_pvp_br0
"table=3,priority=10
actions=normal"

With these, I expect the packet to be sent to vnet0, but
it’s not.
Actually,
the datapath rule looks odd, while the userspace rules seem
to match:

  $ ovs-dpctl dump-flows
  
recirc_id(0),in_port(1),eth(),eth_type(0x8847),mpls(label=100/0xfffff,tc=0/0,ttl=0/0x0,bos=1/1),
packets:13, bytes:1118, used:0.322s,
actions:pop_eth,pop_mpls(eth_type=0x806),recirc(0x19a)
  recirc_id(0x19a),in_port(1),eth_type(0x0806), packets:13,
bytes:884,
used:0.322s, actions:drop

  $ ovs-ofctl dump-flows ovs_pvp_br0 -O OpenFlow13
  cookie=0x0, duration=85.007s, table=0, n_packets=51,
n_bytes=4386,
priority=100,mpls,mpls_label=100
actions=decap(),decap(packet_type(ns=0,type=0x806)),resubmit(,3)
  cookie=0x0, duration=84.990s, table=3, n_packets=51,
n_bytes=3468,
priority=10 actions=NORMAL

The inner packet is ethernet. So the packet type should be
(ns=0,type=0)
?

Forgot to add that I already tried that to start
with, based on the
example,
but as that did not work I tried 0x806.

PS: I have this as a remark in my review notes, i.e., to
explain the
ns and
type usage here.


This resulted in packets being counted at the open flow
level, but it
results in NO data path rules. Do get an error though:

2021-04-01T06:53:36.056Z|00141|dpif(handler37)|WARN|system@ovs-system:
failed to put[create] (Invalid argument)
ufid:3d2d6f6d-5a66-4ace-8b09-7cdcfa5efc8e recirc_id(0),dp_hash(0/0),skb_priority(0/0),in_port(1),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),eth(src=00:00:00:00:00:01/00:00:00:00:00:00,dst=00:00:00:00:00:02/00:00:00:00:00:00),eth_type(0x8847),mpls(label=100/0xfffff,tc=0/0,ttl=64/0x0,bos=1/1),
actions:pop_eth,pop_mpls(eth_type=0x6558),set(eth()),recirc(0x4c)

This set(eth) before the recirc is the problem i guesss. I need
to check

I could reproduce the problem. It has nothing to do with ARP or IP. Unlike my test scripts, in your test you are setting the mac address after the encap action

Ovs-vswitchd is programming a set(eth(dst) action between the pop_mpls and recirc as it sees a difference in mac address in flow structure and base_flow structure.

The mac address in flow structure is not cleared in PT_ETH handling of xlate_generic_decap_action but it is cleared in base_flow in the decap handling of PT_ETH in commit_encap_decap_action function

Due to this difference the set(eth(dst) action will be programmed to the datapath.

Also, I see that in commit_set_ether_action Function “flow->packet_type != htonl(PT_ETH)” is used to check if the packet is ethernet instead of base_flow->packet_type.

I assume check on base_flow->packet_type make more sense here ?

I tried to fix this issue in 2 different ways.

1 I have cleared the mac address in flow structure in PT_ETH handling of xlate_generic_decap action.

2 In the commit_set_ether action I changed the check from “flow->packet_type != htonl(PT_ETH)” to “base_flow->packet_type != htonl(PT_ETH))”.

Though both of them solves this problem, couple of NSH regression tests are failing

2291: nsh - md1 encap over a veth link FAILED (nsh.at:85)

58022292: nsh - md2 encap over a veth link FAILED (nsh.at:213)

I see that they are failing as they are expecting a set(eth(dst) between the the pop_nsh and the recirc.

Set(eth) action is because of the reasons explained above –

Datapath actions: push_nsh(flags=0,ttl=63,mdtype=1,np=3,spi=0x1234,si=255,c1=0x11223344,c2=0x0,c3=0x0,c4=0x0),push_eth(src=00:00:00:00:00:00,dst=11:22:33:44:55:66),pop_eth,pop_nsh(),set(eth(dst=11:22:33:44:55:66)),recirc(0x1)

In my understanding set(eth) here is wrong as there is no set ethernet action in the userspace rule
- Hide quoted text -

table=0,in_port=4,dl_type=0x894f,nsh_mdtype=1,nsh_spi=0x1234,nsh_c1=0x11223344,actions=decap(),decap(),2



Could someone comment ?

Maybe Jan can answer as he did the NSH implementation, however, what would be of interest if you can give me an example of how the encap() decap() for this would be used in real life so I’m sure I’m testing it correctly?

What I did so far was to encapsulate all traffic going from a VM to the physical port in MPLS using the flows like:

ovs-ofctl add-flow -O OpenFlow13 ovs_pvp_br0 "priority=100,in_port=vnet0,actions=encap(mpls(ether_type=0x8847)),set_mpls_label:100,encap(ethernet),,set_field:00:00:00:00:00:02->dl_ds
t,set_field:00:00:00:00:00:01->dl_src,output:enp5s0f0"

Then I would capture this traffic and sent it back over the same port, hoping it would come out as plane traffic with the following rule:

ovs-ofctl add-flow -O OpenFlow15 ovs_pvp_br0 "priority=100,dl_type=0x8847,mpls_label=100 actions=decap(),decap(packet_type(ns=0,type=0)),resubmit(,3)" ovs-ofctl add-flow -O OpenFlow15 ovs_pvp_br0 "table=3,priority=10 actions=normal"

If this is correct, let me know, and if Jan does not reply, I’ll try to understand the code in this area and see if I can find out some details…

//Eelco

2021-04-01T06:53:36.056Z|00142|dpif(handler37)|WARN|system@ovs-system:
execute pop_eth,pop_mpls(eth_type=0x6558),set(eth()),recirc(0x4c)
failed
(Invalid argument) on packet mpls,vlan_tci=0x0000,dl_src=00:00:00:00:00:01,dl_dst=00:00:00:00:00:02,mpls_label=100,mpls_tc=0,mpls_ttl=64,mpls_bos=1
 with metadata skb_priority(0),skb_mark(0),in_port(1) mtu 0

Are there missing parts in my kernel that do not get properly
detected by
the feature detection?

$ ovs-appctl dpif/show-dp-features ovs_pvp_br0
Masked set action: Yes
Tunnel push pop: No
Ufid: Yes
Truncate action: Yes
Clone action: Yes
Sample nesting: 10
Conntrack eventmask: Yes
Conntrack clear: Yes
Max dp_hash algorithm: 0
Check pkt length action: Yes
Conntrack timeout policy: Yes
Explicit Drop action: No
Optimized Balance TCP mode: No
l2 MPLS tunnelling: Yes
Max VLAN headers: 2
Max MPLS depth: 3
Recirc: Yes
CT state: Yes
CT zone: Yes
CT mark: Yes
CT label: Yes
CT state NAT: Yes
CT orig tuple: Yes
CT orig tuple for IPv6: Yes
IPv6 ND Extension: No

You are good

I am not sure what is going wrong. Your test case looks same as
the unit
test i added.

I tried myself again and this is i get

ovs-ofctl -O OpenFlow13 add-flow br_mpls2
"in_port=$egress_port,dl_type=0x8847
+actions=decap(),decap(packet_type(ns=0,type=0),goto_table:1"
ovs-ofctl -O OpenFlow13 add-flow br_mpls2
+"table=1,in_port=$egress_port,dl_type=0x0800,nw_dst=1.1.1.2
+actions=set_field:00:00:00:00:00:02->dl_dst,set_field:00:00:00:00:00:01->dl_sr
+c output:$ingress_port"

recirc_id(0x3),in_port(6),eth(src=36:b1:ee:7c:01:03,dst=36:b1:ee:7c:01:02),eth_
+type(0x0800),ipv4(dst=1.1.1.2,frag=no), packets:3, bytes:294,
used:0.837s,
+actions:set(eth(src=00:00:00:00:00:01,dst=00:00:00:00:00:02)),4
recirc_id(0),in_port(6),eth(),eth_type(0x8847),mpls(label=0/0x0,tc=0/0,ttl=0/0x
+0,bos=1/1), packets:3, bytes:348, used:0.837s,
+actions:pop_eth,pop_mpls(eth_type=0x6558),recirc(0x3)

The packet to the ovs is
ETH|MPLS|ETH|IP ?
How it is differnt from you test case?

Mine is ETH|MPLS|ETH|ARP, which works fine with pop_mpls

I am wondering how old mpls pop  action works
could you please put down the userspace and datapath rules when
you used
pop_mpls.

In my understanding it can never work as what you have after MPLS is
ethernet and not ARP.

It’s ethernet + ARP, but here are my rules:

To clarify

The test vector for Decap Test case
ETH|MPLS|ETH|ARP
The test vector for pop mpls test case
ETH|MPLS|ARP|

The above understanding correct?

Guess our emails crossed ;) I was sending in the same packet for both the
test cases, so

ETH|MPLS|ETH|ARP

Which with decap() is resulting in the rules not being programmed

With popmpls I saw the packets in being received, but did not notice the incorrect use of popmpls so my packet after popmpls looks like ETH|ETH|ARP.

So I guess all that remains is why the data path rules is not accepted for
ARP with the decap.


dpctl:

recirc_id(0),in_port(2),eth(),eth_type(0x8847),mpls(label=100/0xfffff,tc=0/0,ttl=0/0x0,bos=1/1),
packets:64, bytes:5504, used:0.444s,
actions:pop_mpls(eth_type=0x806),recirc(0x80d)
recirc_id(0x80d),in_port(2),eth(src=00:00:00:00:00:01,dst=00:00:00:00:00:02),eth_type(0x0806),
packets:64, bytes:5248, used:0.444s, actions:3,1

ofctl:

OFPST_FLOW reply (OF1.5) (xid=0x2):
 cookie=0x0, duration=178.890s, table=0, n_packets=127,
n_bytes=10922,
idle_age=0, priority=100,mpls,mpls_label=100
actions=pop_mpls:0x0806,resubmit(,3)
 cookie=0x0, duration=178.873s, table=3, n_packets=127,
n_bytes=10414,
idle_age=0, priority=10 actions=NORMAL


Thanks for your time.

Your welcome


If I use the old way, doing pop_mpls, it works fine:


ovs-ofctl del-flows ovs_pvp_br0
ovs-ofctl add-flow -O OpenFlow13 ovs_pvp_br0
"priority=100,dl_type=0x8847,mpls_label=100
actions=pop_mpls:0x0806,resubmit(,3)"
ovs-ofctl add-flow -O OpenFlow13 ovs_pvp_br0
"table=3,priority=10
actions=normal"


I also noticed (despite the test example) to make
encap work, I had
to set
the ethernet MAC addresses, or else the packets were not
getting out.
So something like:

  ovs-ofctl add-flow -O OpenFlow13
ovs_pvp_br0 "priority=100,in_port=vnet0,actions=encap(mpls(ether_type=0x8847)),set_mpls_label:100,encap(ethernet),,set_field:00:00:00:00:00:02->dl_dst,set_field:00:00:00:00:00:01->dl_src,output:enp5s0f0



The packets are not going out because you are sending the packet
on a
real nic and not on a virtual inerface (veth pair) ?

So for a real NIC we need to set the MAC addresses, maybe
some where
in the
documentation we should add an example on how to use
this feature?

Maybe the test case can be made more realistic? Once I
understand the
failure, I can continue with the review.


Cheers,

Eelco

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