Sending UDP packets in a loop can be done in a separate goroutine. We
can't do this in ContainerAction because the container will terminate
early.
Locally, scripts/iptables_tests.sh runs ~40 seconds faster.
Fixes a NAT bug that manifested as:
- A SYN was sent from gVisor to another host, unaffected by iptables.
- The corresponding SYN/ACK was NATted by a PREROUTING REDIRECT rule
despite being part of the existing connection.
- The socket that sent the SYN never received the SYN/ACK and thus a
connection could not be established.
We handle this (as Linux does) by tracking all connections, inserting a
no-op conntrack rule for new connections with no rules of their own.
Needed for istio support (#170).
Loopback traffic is not affected by rules in the PREROUTING chain.
This change is also necessary for istio's envoy to talk to other
components in the same pod.
Connection tracking is used to track packets in prerouting and
output hooks of iptables. The NAT rules modify the tuples in
connections. The connection tracking code modifies the packets by
looking at the modified tuples.
Fixed flakes (tested via --runs_per_test=100) and added skips for
not-yet-implemented features. Once submitted, the iptables tests will be
ready to enable in kokoro.
Enables commands such as:
$ iptables -A INPUT -d 127.0.0.1 -j ACCEPT
$ iptables -t nat -A PREROUTING ! -d 127.0.0.1 -j REDIRECT
Also adds a bunch of REDIRECT+destination tests.
Fix the indentation and print statements.
Moved the NAT redirect tests to new file.
Added negative test to check redirect rule on ports other than
redirected port.
Kevin Krakauer
Nayana Bidari
gVisor bot