Forwarding packets in a single Open vSwitch bridge
I am trying to emulate a L3-switch where multiple machines are connected (in no VLANs or a single VLAN.) Then I would like to configure the switch to forward packets as I want, which I had no luck.
My system configuration:
- Host machine OS: Ubuntu 18.04.
- Open vSwitch 2.9.0
- Client machines: UBuntu 18.04 clients in VirtualBox 5.2.20
What I want to do
(basically emulating a man-in-the-middle attack.)
- VM1, VM2 and VM3 are connected to a virtual switch or bridge (BR0).
- VM1 sends a packet (e.g., HTTP GET request) to VM3.
- BR0 intercepts it and forward it to VM2.
- VM2 sends the response to VM1.
- BR0 forwards it to VM1 like VM3 responding.
What I did:
ovs-vsctl add-br br0: Create a bridge (BR0)- Create VM1,2,3 that use br0 as a network bridge.
- Run different webservers inside VM2 and VM3 (e.g., VM2 returns "hello" at the root wheras VM3 returns "HELLO".)
- Configure IP addresses inside each machine to, say,
- VM1: 192.168.0.2
- VM2: 192.168.0.3
- VM3: 192.168.0.4
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_dst=192.168.0.4,actions=mod_nw_dst=192.168.0.3: Add a flow modifying the destintion IP. Catching packges going to VM3 and forwarding them to VM2 (I hope.)
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_src=192.168.0.3,actions=mod_nw_src=192.168.0.4: Add a flow modifying the source IP. To make the response come from VM3.
What I saw:
However, obviously, it was not successful.
- I can
pingfrom one to another. - I can
cURLfrom one to another. - However, the
mod_nw_dstcommand was not effective. From VM1, I only can see the original response from VM3, which I wanted to forward to VM2.
I googled this a lot and found many articles about forwarding across VLANs, but not like this in a single bridge. Is my implementation incorrect? Otherwise, is it not an intended feature? In that case, what would be the best approach to emulate such things?
Thanks in advance!
EDIT: The result of ovs-ofctl dump-flows br0 is just the above command.
cookie=0x0, duration=157469.378s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_src=192.168.0.3 actions=mod_nw_src:192.168.0.4
cookie=0x0, duration=157462.433s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_dst=192.168.0.4 actions=mod_nw_dst:192.168.0.3
cookie=0x0, duration=157534.866s, table=0, n_packets=0, n_bytes=0, priority=0 actions=NORMAL
forwarding openflow switching openvswitch
asked Nov 21 '18 at 5:44
randusrrandusr
215
|
show 2 more comments
I am trying to emulate a L3-switch where multiple machines are connected (in no VLANs or a single VLAN.) Then I would like to configure the switch to forward packets as I want, which I had no luck.
My system configuration:
- Host machine OS: Ubuntu 18.04.
- Open vSwitch 2.9.0
- Client machines: UBuntu 18.04 clients in VirtualBox 5.2.20
What I want to do
(basically emulating a man-in-the-middle attack.)
- VM1, VM2 and VM3 are connected to a virtual switch or bridge (BR0).
- VM1 sends a packet (e.g., HTTP GET request) to VM3.
- BR0 intercepts it and forward it to VM2.
- VM2 sends the response to VM1.
- BR0 forwards it to VM1 like VM3 responding.
What I did:
ovs-vsctl add-br br0: Create a bridge (BR0)- Create VM1,2,3 that use br0 as a network bridge.
- Run different webservers inside VM2 and VM3 (e.g., VM2 returns "hello" at the root wheras VM3 returns "HELLO".)
- Configure IP addresses inside each machine to, say,
- VM1: 192.168.0.2
- VM2: 192.168.0.3
- VM3: 192.168.0.4
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_dst=192.168.0.4,actions=mod_nw_dst=192.168.0.3: Add a flow modifying the destintion IP. Catching packges going to VM3 and forwarding them to VM2 (I hope.)
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_src=192.168.0.3,actions=mod_nw_src=192.168.0.4: Add a flow modifying the source IP. To make the response come from VM3.
What I saw:
However, obviously, it was not successful.
- I can
pingfrom one to another. - I can
cURLfrom one to another. - However, the
mod_nw_dstcommand was not effective. From VM1, I only can see the original response from VM3, which I wanted to forward to VM2.
I googled this a lot and found many articles about forwarding across VLANs, but not like this in a single bridge. Is my implementation incorrect? Otherwise, is it not an intended feature? In that case, what would be the best approach to emulate such things?
Thanks in advance!
EDIT: The result of ovs-ofctl dump-flows br0 is just the above command.
cookie=0x0, duration=157469.378s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_src=192.168.0.3 actions=mod_nw_src:192.168.0.4
cookie=0x0, duration=157462.433s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_dst=192.168.0.4 actions=mod_nw_dst:192.168.0.3
cookie=0x0, duration=157534.866s, table=0, n_packets=0, n_bytes=0, priority=0 actions=NORMAL
forwarding openflow switching openvswitch
asked Nov 21 '18 at 5:44
randusrrandusr
215
1
What's the full content of your OpenFlow tables (ovs-ofctl dump-flows br0)?
– pchaigno
Nov 21 '18 at 10:08
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
1
It looks like your secondovs-ofctl add-flowcommand wasn't taken into account. Did you get any error message when you ran that command?
– pchaigno
Nov 21 '18 at 20:12
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
1
Did you empty the table before running these commands? There should be a default forwarding rule with aNORMALaction.
– pchaigno
Nov 21 '18 at 20:39
|
show 2 more comments
I am trying to emulate a L3-switch where multiple machines are connected (in no VLANs or a single VLAN.) Then I would like to configure the switch to forward packets as I want, which I had no luck.
My system configuration:
- Host machine OS: Ubuntu 18.04.
- Open vSwitch 2.9.0
- Client machines: UBuntu 18.04 clients in VirtualBox 5.2.20
What I want to do
(basically emulating a man-in-the-middle attack.)
- VM1, VM2 and VM3 are connected to a virtual switch or bridge (BR0).
- VM1 sends a packet (e.g., HTTP GET request) to VM3.
- BR0 intercepts it and forward it to VM2.
- VM2 sends the response to VM1.
- BR0 forwards it to VM1 like VM3 responding.
What I did:
ovs-vsctl add-br br0: Create a bridge (BR0)- Create VM1,2,3 that use br0 as a network bridge.
- Run different webservers inside VM2 and VM3 (e.g., VM2 returns "hello" at the root wheras VM3 returns "HELLO".)
- Configure IP addresses inside each machine to, say,
- VM1: 192.168.0.2
- VM2: 192.168.0.3
- VM3: 192.168.0.4
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_dst=192.168.0.4,actions=mod_nw_dst=192.168.0.3: Add a flow modifying the destintion IP. Catching packges going to VM3 and forwarding them to VM2 (I hope.)
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_src=192.168.0.3,actions=mod_nw_src=192.168.0.4: Add a flow modifying the source IP. To make the response come from VM3.
What I saw:
However, obviously, it was not successful.
- I can
pingfrom one to another. - I can
cURLfrom one to another. - However, the
mod_nw_dstcommand was not effective. From VM1, I only can see the original response from VM3, which I wanted to forward to VM2.
I googled this a lot and found many articles about forwarding across VLANs, but not like this in a single bridge. Is my implementation incorrect? Otherwise, is it not an intended feature? In that case, what would be the best approach to emulate such things?
Thanks in advance!
EDIT: The result of ovs-ofctl dump-flows br0 is just the above command.
cookie=0x0, duration=157469.378s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_src=192.168.0.3 actions=mod_nw_src:192.168.0.4
cookie=0x0, duration=157462.433s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_dst=192.168.0.4 actions=mod_nw_dst:192.168.0.3
cookie=0x0, duration=157534.866s, table=0, n_packets=0, n_bytes=0, priority=0 actions=NORMAL
forwarding openflow switching openvswitch
asked Nov 21 '18 at 5:44
randusrrandusr
215
I am trying to emulate a L3-switch where multiple machines are connected (in no VLANs or a single VLAN.) Then I would like to configure the switch to forward packets as I want, which I had no luck.
My system configuration:
- Host machine OS: Ubuntu 18.04.
- Open vSwitch 2.9.0
- Client machines: UBuntu 18.04 clients in VirtualBox 5.2.20
What I want to do
(basically emulating a man-in-the-middle attack.)
- VM1, VM2 and VM3 are connected to a virtual switch or bridge (BR0).
- VM1 sends a packet (e.g., HTTP GET request) to VM3.
- BR0 intercepts it and forward it to VM2.
- VM2 sends the response to VM1.
- BR0 forwards it to VM1 like VM3 responding.
What I did:
ovs-vsctl add-br br0: Create a bridge (BR0)- Create VM1,2,3 that use br0 as a network bridge.
- Run different webservers inside VM2 and VM3 (e.g., VM2 returns "hello" at the root wheras VM3 returns "HELLO".)
- Configure IP addresses inside each machine to, say,
- VM1: 192.168.0.2
- VM2: 192.168.0.3
- VM3: 192.168.0.4
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_dst=192.168.0.4,actions=mod_nw_dst=192.168.0.3: Add a flow modifying the destintion IP. Catching packges going to VM3 and forwarding them to VM2 (I hope.)
ovs-ofctl --strict add-flow br0 priority=1,tcp,nw_src=192.168.0.3,actions=mod_nw_src=192.168.0.4: Add a flow modifying the source IP. To make the response come from VM3.
What I saw:
However, obviously, it was not successful.
- I can
pingfrom one to another. - I can
cURLfrom one to another. - However, the
mod_nw_dstcommand was not effective. From VM1, I only can see the original response from VM3, which I wanted to forward to VM2.
I googled this a lot and found many articles about forwarding across VLANs, but not like this in a single bridge. Is my implementation incorrect? Otherwise, is it not an intended feature? In that case, what would be the best approach to emulate such things?
Thanks in advance!
EDIT: The result of ovs-ofctl dump-flows br0 is just the above command.
cookie=0x0, duration=157469.378s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_src=192.168.0.3 actions=mod_nw_src:192.168.0.4
cookie=0x0, duration=157462.433s, table=0, n_packets=0, n_bytes=0, priority=1,tcp,nw_dst=192.168.0.4 actions=mod_nw_dst:192.168.0.3
cookie=0x0, duration=157534.866s, table=0, n_packets=0, n_bytes=0, priority=0 actions=NORMAL
forwarding openflow switching openvswitch
forwarding openflow switching openvswitch
asked Nov 21 '18 at 5:44
randusrrandusr
215
asked Nov 21 '18 at 5:44
randusrrandusr
215
edited Nov 24 '18 at 22:29
randusr
asked Nov 21 '18 at 5:44
randusrrandusr
215
asked Nov 21 '18 at 5:44
randusrrandusr
215
asked Nov 21 '18 at 5:44
randusrrandusr
215
215
1
What's the full content of your OpenFlow tables (ovs-ofctl dump-flows br0)?
– pchaigno
Nov 21 '18 at 10:08
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
1
It looks like your secondovs-ofctl add-flowcommand wasn't taken into account. Did you get any error message when you ran that command?
– pchaigno
Nov 21 '18 at 20:12
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
1
Did you empty the table before running these commands? There should be a default forwarding rule with aNORMALaction.
– pchaigno
Nov 21 '18 at 20:39
|
show 2 more comments
1
What's the full content of your OpenFlow tables (ovs-ofctl dump-flows br0)?
– pchaigno
Nov 21 '18 at 10:08
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
1
It looks like your secondovs-ofctl add-flowcommand wasn't taken into account. Did you get any error message when you ran that command?
– pchaigno
Nov 21 '18 at 20:12
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
1
Did you empty the table before running these commands? There should be a default forwarding rule with aNORMALaction.
– pchaigno
Nov 21 '18 at 20:39
1
1
What's the full content of your OpenFlow tables (
ovs-ofctl dump-flows br0)?– pchaigno
Nov 21 '18 at 10:08
What's the full content of your OpenFlow tables (
ovs-ofctl dump-flows br0)?– pchaigno
Nov 21 '18 at 10:08
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
1
1
It looks like your second
ovs-ofctl add-flow command wasn't taken into account. Did you get any error message when you ran that command?– pchaigno
Nov 21 '18 at 20:12
It looks like your second
ovs-ofctl add-flow command wasn't taken into account. Did you get any error message when you ran that command?– pchaigno
Nov 21 '18 at 20:12
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
1
1
Did you empty the table before running these commands? There should be a default forwarding rule with a
NORMAL action.– pchaigno
Nov 21 '18 at 20:39
Did you empty the table before running these commands? There should be a default forwarding rule with a
NORMAL action.– pchaigno
Nov 21 '18 at 20:39
|
show 2 more comments
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1
What's the full content of your OpenFlow tables (
ovs-ofctl dump-flows br0)?– pchaigno
Nov 21 '18 at 10:08
@pchaigno Hi, I just added the table in the text. Thanks!
– randusr
Nov 21 '18 at 19:39
1
It looks like your second
ovs-ofctl add-flowcommand wasn't taken into account. Did you get any error message when you ran that command?– pchaigno
Nov 21 '18 at 20:12
@pchaigno Sorry, that I forgot to add that. I was playing with various configurations and the second command was redacted in the current setup. It didn't give me an error and showed the same result. I updated the table result above.
– randusr
Nov 21 '18 at 20:19
1
Did you empty the table before running these commands? There should be a default forwarding rule with a
NORMALaction.– pchaigno
Nov 21 '18 at 20:39