1. setsockopt(SO_RCVTIMEO, 0) == never timeout
2. float64(time.Microsecond/time.Second) == 0
3. packetimpact tests use a lot of 1s timeouts
This becomes a more significant problem because of a recent change that binds
the sniffer only on the specific testNet interface so now the traffic on the
ctrlNet cannot wake up the blocking call anymore.
PiperOrigin-RevId: 344123465
Summary of the approach: the test runner will set up a few DUTs according to
a flag and pass all the test networks to the testbench. The testbench will only
reside in a single container. The testbench will put all the test networks into
a buffered channel which served as a semaphore and now the user can freely use
t.Parallel() in (sub)tests and the true parallelism will be determined by how
many DUTs are configured. Creating DUTs on demand is not supported yet, the
test author should determine the number of DUTs to be used statically.
Specifically in this change:
- Don't export any global variables about the test network in testbench.
- Sniffer only binds on the local interface because it will be possible to have
multiple interfaces to multiple DUTs in a single testbench container.
- Migrate existing tests to stop using global variables.
PiperOrigin-RevId: 343965962
There are two device names on the test net.
- The sniffer/injector device which is always a linux device. Only the
testbench library is interested in this device.
- The device which is on the DUT. It happens to be the same device as
the former if DUT is linux. An individual test might be interested in
this device if the test cares about the device name.
PiperOrigin-RevId: 332112968
Storing *testing.T on test helper structs is problematic when
subtests are used, because it is possible for nested tests to call
Fatal on parent test, which incorrect terminates the parent test.
For example
func TestOuter(t *testing.T) {
dut := NewDUT(t)
t.Run("first test", func(t *testing.T) {
dut.FallibleCall()
})
t.Run("second test", func(t *testing.T) {
dut.FallibleCall()
}
}
In the example above, assuming `FallibleCall` calls `t.Fatal` on the
`t` it holds, if `dut.FallibleCall` fails in "first test", it will
call `Fatal` on the parent `t`, quitting `TestOuter`. This is not a
behavior we want.
PiperOrigin-RevId: 323350241
Rather than have a struct for the state of each type of connection, such as
TCP/IPv4, UDP/IPv4, TCP/IPv6, etc, have a state for each layer, such as UDP,
TCP, IPv4, IPv6. Those states can be composed into connections.
Tested:
Existing unit tests still pass/fail as expected.
PiperOrigin-RevId: 306703180
Add Sniffer.Drain() which drains the socket's receive buffer by temporarily
setting the socket to non-blocking, and receiving in a loop until EINTR,
EWOULDBLOCK or EAGAIN. This method should be used when long periods of time
elapses without receiving on the socket, because uninteresting packets may have
piled up in the receive buffer, filling it up and causing packets critical to
test operation to be dropped.
PiperOrigin-RevId: 306380480
Zeling Feng
Jay Zhuang
gVisor bot
Bhasker Hariharan
Ian Gudger
Eyal Soha