[ovs-discuss] OVS 2.3.0 issues

[Ben Pfaff]

Thank you for the bug reports!  (In the future I'd suggest one bug
report per email because it makes it easier to handle each one.)

On Thu, Sep 04, 2014 at 07:05:03PM -0700, Saurav Das wrote:
> Possible bug: ovs-ofctl display of actions
> 
> Here is a table-miss-entry which is supposed to match everything. There are
> no instructions associated with this entry.
> 
> cookie=0x0, duration=31.700s, table=5, n_packets=7, n_bytes=686, priority=0
> actions=drop
> 
> According to the OF1.3 spec, when there are no goto-instructions, pipeline
> processing stops, and the action-set should get executed.
> We do believe this is what is happening in the switch - however the display
> "actions=drop" is misleading, and possibly a holdover from OF1.0 behavior,
> when no actions meant drop. Perhaps "actions=execute-action-set" may better
> reflect OF1.3 behavior when there are no instructions.

I can see how that could be misunderstood, but I doubt that we're going
to change such a long-standing OVS behavior on that basis.  Certainly
not to something as awkward and backward-incompatible as
"execute-action-set"!  I think that it's possible to change it to just
"actions=" without any actions specified in a backward-compatible
manner, and if that's better than I'd consider it.

> Possible bug: group stats don't update
> 
> Here is a group definition:
> 
> group_id=536870916,type=indirect,bucket=weight:0,actions=dec_ttl,set_field:00:00:01:01:01:80->eth_src,output:4
> 
> Here are the stats:
> 
> group_id=536870916,duration=202.091s,ref_count=0,packet_count=0,byte_count=0,bucket0:packet_count=0,byte_count=0
> 
> None of the counts go up,  yet I know traffic is being processed by this
> group, as there is no other place where I have specified that packets
> should go out of port 4.

Unfortunately OVS 2.3 does not implement group stats.  They are
available on master, though, and will be in OVS 2.4.

> Possible bug: group doing MPLS stuff doesn't work
> 
> 
> Here is the flow that points to the group (as part of the actions written
> to an action-set):
> 
> cookie=0x0, duration=31.703s, table=2, n_packets=7, n_bytes=686,
> priority=65520,ip,nw_dst=7.7.7.0/24
>  actions=write_actions(push_mpls:0x8847,set_field:103->mpls_label,group:2684354566),goto_table:5
> 
> In table 5, the packets hit the table-miss-entry, which has no
> instructions, so the action-set gets executed.
> 
> Here is the group definition:
> 
> group_id=2684354566,type=indirect,bucket=weight:0,actions=dec_mpls_ttl,set_field:00:00:01:01:01:80->eth_src,set_field:00:00:02:02:02:80->eth_dst,output:6
> 
> Here are the error messages we see in the logs:
> 
> 
> 2014-08-29T23:58:53.367Z|00001|dpif(handler358)|WARN|system at ovs-system:
> failed to put[create] (Invalid argument)
> dp_hash(0/0),recirc_id(0),skb_priority(0),in_port(5),skb_mark(0/0),eth(src=00:00:00:00:02:01,dst=00:00:01:01:01:80),eth_type(0x0800),ipv4(src=
> 10.0.2.1/255.255.255.255,dst=7.7.7.7/255.255.255.255,proto=1/0xff,tos=0/0xfc,ttl=64/0xff,frag=no/0xff),icmp(type=8,code=0),
> actions:set(eth(src=00:00:01:01:01:80,dst=00:00:02:02:02:80)),push_mpls(label=103,tc=0,ttl=63,bos=1,eth_type=0x8847),7
> 
> 2014-08-29T23:58:53.367Z|00002|dpif(handler358)|WARN|system at ovs-system:
> execute
> set(eth(src=00:00:01:01:01:80,dst=00:00:02:02:02:80)),push_mpls(label=103,tc=0,ttl=63,bos=1,eth_type=0x8847),7
> failed (Invalid argument) on packet
> icmp,metadata=0,in_port=0,vlan_tci=0x0000,dl_src=00:00:00:00:02:01,dl_dst=00:00:01:01:01:80,nw_src=10.0.2.1,nw_dst=7.7.7.7,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0

Hmm, that's a strange error.  Are you by chance running an older kernel
module that doesn't support the MPLS actions?  Userspace should detect
that and fall back to implementing MPLS itself, but it's possible that
that logic is failing.