[ovs-discuss] not seeing return packets from IN_PORT

Aaron Rosen arosen at clemson.edu
Tue Jan 10 20:02:22 UTC 2012


Here are lines (154-158) from here http://codepad.org/APdmOTGN (more debug)

Thanks,

Aaron

Jan 10 14:46:07 localhost ovs-vswitchd: 04385|dpif|DBG|system at dp0: miss
upcall:
Jan 10 14:46:07 localhost ovs-vswitchd:
in_port(0),eth(src=00:1f:29:32:92:4d,dst=00:1b:21:6a:85:88),eth_type(0x0800),ipv4(src=10.0.0.10,dst=10.0.0.13,proto=6,tos=0,ttl=64,frag=no),tcp(src=38710,dst=5004)
Jan 10 14:46:07 localhost ovs-vswitchd: 00:1f:29:32:92:4d >
00:1b:21:6a:85:88, ethertype IPv4 (0x0800), length 74: 10.0.0.10.38710 >
10.0.0.13.5004: S 3410511224:3410511224(0) win 14600 <mss
1460,sackOK,timestamp 9255759 0,nop,wscale 6>
Jan 10 14:46:07 localhost ovs-vswitchd: 04386|dpif|DBG|system at dp0: execute
set(eth(src=00:1f:29:32:92:4d,dst=00:1f:29:32:92:4d)),set(ipv4(src=10.0.0.10,dst=10.0.0.10,proto=6,tos=0,ttl=64,frag=no)),set(tcp(src=38710,dst=9877)),0
on packet 00:1f:29:32:92:4d > 00:1b:21:6a:85:88, ethertype IPv4 (0x0800),
length 74: 10.0.0.10.38710 > 10.0.0.13.5004: S 3410511224:3410511224(0) win
14600 <mss 1460,sackOK,timestamp 9255759 0,nop,wscale 6>
Jan 10 14:46:07 localhost ovs-vswitchd: 04387|dpif|DBG|system at dp0:
put[create][modify]
in_port(0),eth(src=00:1f:29:32:92:4d,dst=00:1b:21:6a:85:88),eth_type(0x0800),ipv4(src=10.0.0.10,dst=10.0.0.13,proto=6,tos=0,ttl=64,frag=no),tcp(src=38710,dst=5004),
actions:set(eth(src=00:1f:29:32:92:4d,dst=00:1f:29:32:92:4d)),set(ipv4(src=10.0.0.10,dst=10.0.0.10,proto=6,tos=0,ttl=64,frag=no)),set(tcp(src=38710,dst=9877)),0



On Tue, Jan 10, 2012 at 1:39 PM, Ben Pfaff <blp at nicira.com> wrote:

> I'd expect such packets to show up in tcpdump in any case.
>
> On Tue, Jan 10, 2012 at 01:35:48PM -0500, Aaron Rosen wrote:
> > I'd be curious what the expected behavior should be if linux sees a
> packet
> > arriving on an interface matching it's dl_src/src_ip. (Since this should
> > have probably gone through lo ).
> >
> > I also enabled log_martians and it's not saying anything about this.
> >
> > Thanks,
> >
> > Aaron
> >
> > On Tue, Jan 10, 2012 at 1:32 PM, Aaron Rosen <arosen at clemson.edu> wrote:
> >
> > > These packets are the normal SYN packets to initial a TCP connection.
> > >
> > > The weird thing though is if I use this flow_mod it works fine:
>  (using a
> > > fake ip/mac as the response).
> > >
> > >  cookie=0x0, duration=6.622s, table=0, n_packets=93776,
> n_bytes=6191149,
> > >
> idle_timeout=100,priority=65535,tcp,in_port=65534,vlan_tci=0x0000,dl_src=00:1f:29:32:92:4d,dl_dst=00:1b:21:6a:85:88,nw_src=10.0.0.10,nw_dst=10.0.0.13,nw_tos=0,tp_src=53641,tp_dst=5004
> > >
> actions=mod_dl_src:66:f3:43:38:f4:a2,mod_dl_dst:00:1f:29:32:92:4d,mod_nw_src:10.0.0.100,mod_nw_dst:10.0.0.10,mod_tp_dst:9877,IN_PORT
> > >
> > >
> > > Then on return packets for that I have this: (so the client is tricked
> in
> > > to connecting to 10.0.0.100 which is really it's self. Though I don't
> want
> > > to have to rely on having an extra IP to do this.
> > >
> > >  cookie=0x0, duration=6.622s, table=0, n_packets=143378,
> > > n_bytes=158529948,
> > >
> idle_timeout=100,tcp,in_port=65534,dl_src=00:1f:29:32:92:4d,nw_src=10.0.0.10,nw_dst=10.0.0.100,tp_src=9877,tp_dst=53641
> > >
> actions=mod_dl_src:00:1b:21:6a:85:88,mod_dl_dst:00:1f:29:32:92:4d,mod_nw_dst:10.0.0.10,mod_nw_src:10.0.0.13,mod_tp_src:5004,IN_PORT
> > >
> > >
> > >
> > > On Tue, Jan 10, 2012 at 1:21 PM, Ben Pfaff <blp at nicira.com> wrote:
> > >
> > >> The datapath actions look like what I'd expect to see.  I'd expect the
> > >> modified packets to show up in tcpdump.  I see that there are only two
> > >> such packets over an 18-second period.  Can you send them faster?  It
> > >> looks like the second packet didn't get caught by the kernel flow
> > >> ("used:never") so both packets were actually processed in userspace;
> > >> perhaps there is a bug in the userspace processing, which is currently
> > >> in transition.
> > >>
> > >> On Tue, Jan 10, 2012 at 01:12:59PM -0500, Aaron Rosen wrote:
> > >> > pg46 openvswitch # ovs-ofctl dump-flows dp0
> > >> > NXST_FLOW reply (xid=0x4):
> > >> > # Removed other flows here for paste...
> > >> >  cookie=0x0, duration=18.467s, table=0, n_packets=2, n_bytes=148,
> > >> >
> > >>
> idle_timeout=100,priority=65535,tcp,in_port=65534,vlan_tci=0x0000,dl_src=00:1f:29:32:92:4d,dl_dst=00:1b:21:6a:85:88,nw_src=10.0.0.10,nw_dst=10.0.0.13,nw_tos=0,tp_src=58209,tp_dst=5004
> > >> >
> > >>
> actions=mod_dl_src:00:1f:29:32:92:4d,mod_dl_dst:00:1f:29:32:92:4d,mod_nw_src:10.0.0.10,mod_nw_dst:10.0.0.10,mod_tp_dst:9877,IN_PORT
> > >> > *
> > >> > *
> > >> > pg46 openvswitch # ovs-dpctl dump-flows dp0
> > >> >
> > >>
> in_port(0),eth(src=00:1f:29:32:92:4d,dst=00:1b:21:6a:85:88),eth_type(0x0800),ipv4(src=10.0.0.10,dst=10.0.0.13,proto=6,tos=0,ttl=64,frag=no),tcp(src=58209,dst=5004),
> > >> > packets:0, bytes:0, used:never,
> > >> >
> > >>
> actions:set(eth(src=00:1f:29:32:92:4d,dst=00:1f:29:32:92:4d)),set(ipv4(src=10.0.0.10,dst=10.0.0.10,proto=6,tos=0,ttl=64,frag=no)),set(tcp(src=58209,dst=9877)),0
> > >> >
> > >> >
> > >> > pg46 openvswitch # ovs-appctl -t ovs-vswitchd  ofproto/trace dp0
> > >> >
> > >>
> 'in_port(0),eth(src=00:1f:29:32:92:4d,dst=00:1b:21:6a:85:88),eth_type(0x0800),ipv4(src=10.0.0.10,dst=10.0.0.13,proto=6,tos=0,ttl=64,frag=no),tcp(src=58209,dst=5004)'
> > >> > Flow: priority0:tunnel0:in_portfffe:tci(0)
> > >> > mac00:1f:29:32:92:4d->00:1b:21:6a:85:88 type0800 proto6 tos0 ttl64
> > >> > ip10.0.0.10->10.0.0.13 port58209->5004
> > >> > Rule: table=0 cookie=0
> > >> >
> > >>
> priority=65535,tcp,in_port=65534,vlan_tci=0x0000,dl_src=00:1f:29:32:92:4d,dl_dst=00:1b:21:6a:85:88,nw_src=10.0.0.10,nw_dst=10.0.0.13,nw_tos=0,tp_src=58209,tp_dst=5004
> > >> > OpenFlow
> > >> >
> > >>
> actions=mod_dl_src:00:1f:29:32:92:4d,mod_dl_dst:00:1f:29:32:92:4d,mod_nw_src:10.0.0.10,mod_nw_dst:10.0.0.10,mod_tp_dst:9877,IN_PORT
> > >> >
> > >> > Final flow: priority0:tunnel0:in_portfffe:tci(0)
> > >> > mac00:1f:29:32:92:4d->00:1f:29:32:92:4d type0800 proto6 tos0 ttl64
> > >> > ip10.0.0.10->10.0.0.10 port58209->9877
> > >> > Datapath actions:
> > >> >
> > >>
> set(eth(src=00:1f:29:32:92:4d,dst=00:1f:29:32:92:4d)),set(ipv4(src=10.0.0.10,dst=10.0.0.10,proto=6,tos=0,ttl=64,frag=no)),set(tcp(src=58209,dst=9877)),0
> > >> >
> > >> >
> > >> > On Tue, Jan 10, 2012 at 12:28 PM, Ben Pfaff <blp at nicira.com> wrote:
> > >> > > On Tue, Jan 10, 2012 at 12:15:39PM -0500, Aaron Rosen wrote:
> > >> > >> Hello,
> > >> > >>
> > >> > >> I have a quick question about what could be happening to these
> > >> packets.
> > >> > >>
> > >> > >> I start a tcp connection 10.0.0.10 > 10.0.0.13:
> > >> > >>
> > >> > >> 12:02:55.961344 00:1f:29:32:92:4d (oui Unknown) >
> 00:1b:21:6a:85:88
> > >> > >> (oui Unknown), ethertype IPv4 (0x0800), length 74:
> 10.0.0.10.50490 >
> > >> > >> 10.0.0.13.5004: S
> > >> > >>
> > >> > >> Then the following flow entry is installed in order to handle
> this
> > >> flow:
> > >> > >>
> > >> > >> ?cookie=0x0, duration=4.55s, table=0, n_packets=1, n_bytes=74,
> > >> > >>
> > >> >
> > >>
> idle_timeout=10,priority=65535,tcp,in_port=65534,vlan_tci=0x0000,dl_src=00:1f:29:32:92:4d,dl_dst=00:1b:21:6a:85:88,nw_src=10.0.0.10,nw_dst=10.0.0.13,nw_tos=0,tp_src=50490,tp_dst=5004
> > >> > >>
> > >> >
> > >>
> actions=mod_dl_src:00:1f:29:32:92:4d,mod_dl_dst:00:1f:29:32:92:4d,mod_nw_src:10.0.0.10,mod_nw_dst:10.0.0.10,mod_tp_dst:9877,IN_PORT
> > >> > >>
> > >> > >>
> > >> > >> Though, I never see these packets come back in on the interface
> that
> > >> > >> it went out on.
> > >> > >
> > >> > > What does "ovs-appctl ofproto/trace" or "ovs-dpctl dump-flows"
> show
> > >> > > happening to the packets?
> > >> >
> > >> >
> > >> >
> > >> > --
> > >> > Aaron O. Rosen
> > >> > Masters Student - Network Communication
> > >> > 306B Fluor Daniel
> > >>
> > >
> > >
> > >
> > > --
> > > Aaron O. Rosen
> > > Masters Student - Network Communication
> > > 306B Fluor Daniel
> > >
> > >
> > >
> >
> >
> > --
> > Aaron O. Rosen
> > Masters Student - Network Communication
> > 306B Fluor Daniel
>



-- 
Aaron O. Rosen
Masters Student - Network Communication
306B Fluor Daniel
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