[ovs-dev] [PATCH] Avoid crash in OvS while transmitting fragmented packets over tunnel.
Darrell Ball
dlu998 at gmail.com
Wed May 16 16:56:23 UTC 2018
Thanks Rohith
MPLSoGRE was not among my top 10 guesses :-); I’ll take a look.
Darrell
On Mon, May 14, 2018 at 3:36 AM, Rohith Basavaraja <
rohith.basavaraja at ericsson.com> wrote:
> 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 at 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 at 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 at 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 ç= 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 <dlu998 at gmail.com>
> *Date: *Friday, 11 May 2018 at 10:33 PM
> *To: *Rohith Basavaraja <rohith.basavaraja at ericsson.com>
> *Cc: *Darrell Ball <dball at vmware.com>, "dev at openvswitch.org" <
> dev at openvswitch.org>
> *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 <
> rohith.basavaraja at ericsson.com> 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" <dball at vmware.com> wrote:
>
> Thanks Rohith
> I see this patch was applied, but I have one question inline.
>
>
> On 4/20/18, 1:48 AM, "ovs-dev-bounces at openvswitch.org on behalf of
> Rohith Basavaraja" <ovs-dev-bounces at openvswitch.org on behalf of
> rohith.basavaraja at ericsson.com> 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 <jan.scheurich at ericsson.com>
> From: Rohith Basavaraja <rohith.basavaraja at ericsson.com>
> CC: Jan Scheurich <jan.scheurich at ericsson.com>
>
> ---
> 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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