Fix MPTCP recipe #357
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Fix MPTCP recipe #357
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jtluka
previously approved these changes
Jan 16, 2024
rp_filter (reverse path filtering) is responsible for not allowing responding to packets on a different interface than the packet appeared on. It has to be disabled for MPTCP on IPv4. IPv6 doesn't have rp_filter on sysfs, but firewalld or ip6tables might configure it themselves. We do not run testing on machines where firewalld is enabled, nor do we use ip6tables so no issues should appear.
Apparently there's a difference between "adding an mptcp endpoint" and "adding an mptcp endpoint to a device". pyroute doesn't support dev in the `mptcp endpoint add` call so we have to use a shell command. (svinota/pyroute2#782)
We are binding the client port to be consistent in multi-flow scenarios. However, our mptcp scenario opens 2 additional ports and not one. Only the first one binds to the specified client port, the second one is random. This would be fine, but there's a bug where mptcp doesn't close ports immediately (RHEL-21492). This raises an "Address already in use" error when the client attempts to bind the client port. We don't bind the client port to mitigate this issue, but also because, as specified before, it doesn't matter whether it's bound or not.
jtluka
approved these changes
Jan 17, 2024
olichtne
approved these changes
Jan 17, 2024
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Description
This PR makes our MPTCP recipe actually test 2 flows. It also makes perf flows not bind on client ports, because currently there's a kernel bug which keeps ports open even after they're closed.
Tests
Tested manually, 2 subflows now work.
Reviews
@olichtne @jtluka