Hi Darell,

In my simple setup I have interface in namespace ns1 with IP 192.168.10.10 and 
in connected to bridge br-in1 (Just mentioning relevant config)
And br-in1 I have following flows.

lab@ubuntu-vm:/var/log/openvswitch$ sudo ovs-ofctl -OOpenFlow13 dump-flows 
br-in1
 cookie=0x0, duration=83.662s, table=0, n_packets=75, n_bytes=7294, 
in_port="br-in1-ns1" 
actions=push_mpls:0x8847,set_field:666->mpls_label,output:gre1
 cookie=0x0, duration=83.644s, table=0, n_packets=75, n_bytes=7594, 
mpls,in_port=gre1,mpls_label=999 
actions=pop_mpls:0x0800,set_field:26:ed:b2:5d:50:d7->eth_dst,output:"br-in1-ns1"

When I ping the remote interface things works fine

lab@ubuntu-vm:~$ sudo ip netns exec ns2 ping -W 1 192.168.10.10
PING 192.168.10.10 (192.168.10.10) 56(84) bytes of data.
64 bytes from 192.168.10.10: icmp_seq=1 ttl=64 time=1.62 ms
64 bytes from 192.168.10.10: icmp_seq=2 ttl=64 time=0.723 ms

and the corresponding dpctl entries are are as follows

lab@ubuntu-vm:~/testsuites$ sudo ovs-appctl dpif/dump-flows br-in1

tunnel(src=10.0.0.2,dst=10.0.0.1,flags(-df-csum)),recirc_id(0),in_port(7),packet_type(ns=0,id=0),eth(dst=26:ed:b2:5d:50:d7),eth_type(0x8847),mpls(label=999/0xfffff,tc=0/0,ttl=64/0x0,bos=1/1),
 packets:33, bytes:3366, used:0.978s, actions:pop_mpls(eth_type=0x800),5

recirc_id(0),in_port(5),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(tos=0/0xfc,ttl=64,frag=no),
 packets:33, bytes:3234, used:0.978s, 
actions:push_mpls(label=666,tc=0,ttl=64,bos=1,eth_type=0x8847),clone(tnl_push(tnl_port(7),header(size=38,type=3,eth(dst=86:67:03:ad:e7:e9,src=7a:9f:1f:ce:fc:b6,dl_type=0x0800),ipv4(src=10.0.0.1,dst=10.0.0.2,proto=47,tos=0,ttl=64,frag=0x4000),gre((flags=0x0,proto=0x6558))),out_port(2)),8)


Then Moments I start transmitting the fragmented packet (by increasing the 
packet size) I hit the assert mentioned in the problem.

sudo ip netns exec ns2 ping -s 5000 -W 1 192.168.10.10 <=== Note packet size is 
increased to force fragmentation at the sender.

2018-05-14T18:35:44.571Z|00114|util|EMER|lib/odp-util.c:7008: assertion 
flow->nw_proto == base_flow->nw_proto && flow->nw_frag == base_flow->nw_frag 
failed in commit_set_ipv4_action()
2018-05-14T18:35:44.835Z|00002|daemon_unix(monitor)|ERR|1 crashes: pid 19200 
died, killed (Aborted), core dumped, restarting

Thanks
Rohith

From: Darrell Ball <[email protected]>
Date: Friday, 11 May 2018 at 10:33 PM
To: Rohith Basavaraja <[email protected]>
Cc: Darrell Ball <[email protected]>, "[email protected]" 
<[email protected]>
Subject: Re: [ovs-dev] [PATCH] Avoid crash in OvS while transmitting fragmented 
packets over tunnel.



On Thu, May 10, 2018 at 11:35 PM, Rohith Basavaraja 
<[email protected]<mailto:[email protected]>> wrote:
Hi Darell,

I reproduce the issue by making VM to transmit fragmented packets and in OvS if 
we have corresponding rule
to transmit the received fragmented packet (from VM) over tunnel then I always 
hit the crash.

Thanks Rohith

Unfortunately, I don't hit the assert.
I even tried again with the latest master with this change removed.
I used Geneve for the last test, but I am pretty sure I used Vxlan as well for 
this kind of test b4, as I use it often as well.

Would you mind describing your test in more detail (packets and flows)?

Thanks Darrell




Thanks
Rohith

On 11/05/18, 2:16 AM, "Darrell Ball" 
<[email protected]<mailto:[email protected]>> wrote:

    Thanks Rohith
    I see this patch was applied, but I have one question inline.


    On 4/20/18, 1:48 AM, 
"[email protected]<mailto:[email protected]> on 
behalf of Rohith Basavaraja" 
<[email protected]<mailto:[email protected]> on 
behalf of 
[email protected]<mailto:[email protected]>> wrote:

        Currently when fragmented packets are to be transmitted in to tunnel,
        base_flow->nw_frag which was initially non-zero at reception is not
        reset to zero when the base_flow and flow are rewritten
        as part of the emulated tnl_push action in the ofproto-dpif-xlate
        module.

        Because of this when fragmented packets are transmitted out of tunnel,
        we hit crash caused by the following assert.

        lib/odp-util.c:5654: assertion flow->nw_proto == base_flow->nw_proto &&
        flow->nw_frag == base_flow->nw_frag failed in commit_set_ipv4_action()

    Can you describe how you hit this assertion?
    I have some testing in and around this code, but have not hit this yet, so 
I was curious?

        With the following change propagate_tunnel_data_to_flow__
        is modified to reset *nw_frag* to zero.


        Also, that currently we don't
        fragment tunnelled packets, we should reset *nw_frag* to zero in
        propagate_tunnel_data_to_flow__.

        Signed-off-by: Jan Scheurich 
<[email protected]<mailto:[email protected]>>
        From: Rohith Basavaraja 
<[email protected]<mailto:[email protected]>>
        CC: Jan Scheurich 
<[email protected]<mailto:[email protected]>>

        ---
         ofproto/ofproto-dpif-xlate.c | 1 +
         1 file changed, 1 insertion(+)

        diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
        index 94e3ddb..e9ed037 100644
        --- a/ofproto/ofproto-dpif-xlate.c
        +++ b/ofproto/ofproto-dpif-xlate.c
        @@ -3310,6 +3310,7 @@ propagate_tunnel_data_to_flow__(struct flow 
*dst_flow,
             dst_flow->ipv6_dst = src_flow->tunnel.ipv6_dst;
             dst_flow->ipv6_src = src_flow->tunnel.ipv6_src;

        +    dst_flow->nw_frag = 0; /* Tunnel packets are unfragmented. */


             dst_flow->nw_tos = src_flow->tunnel.ip_tos;
             dst_flow->nw_ttl = src_flow->tunnel.ip_ttl;
             dst_flow->tp_dst = src_flow->tunnel.tp_dst;
        --
        1.9.1




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