passt/test/dhcp, branch 2023_03_29.b10b983

test: Group tests by mode then protocol, rather than the reverse

2022-09-13T09:12:41+00:00

For example, passt/dhcp rather than dhcp/passt.  This is more
consistent with the two_guests and other test groups, and makes some
other cleanups simpler.

Signed-off-by: David Gibson

test: Only select a single interface or gateway in tests

2022-08-20T17:07:12+00:00

The queries we use in the test scripts to locate the external interface
or gateway can return multiple results.  We get away with this because the
way we parse command output only looks at the last line.  It's not really
correct, though, and improvements to our handling of command output will
mean it breaks.

Signed-off-by: David Gibson

Separately locate external interfaces for IPv4 and IPv6

2022-07-30T19:57:50+00:00

Now that the back end allows passt/pasta to use different external
interfaces for IPv4 and IPv6, use that to do the right thing in the case
that the host has IPv4 and IPv6 connectivity via different interfaces.
If the user hasn't explicitly chosen an interface, separately search for
a suitable external interface for each protocol.

As a bonus, this substantially simplifies the external interface probe.  It
also eliminates a subtle confusing case where in some circumstances we
would pick the first interface in interface index order, and sometimes in
order of routes returned from netlink.  On some network configurations that
could cause tests to fail, because the logic in the tests was subtly
different (it always used route order).

Signed-off-by: David Gibson

tests: Correct determination of host interface name in tests

2022-07-30T19:57:14+00:00

By default, passt itself attaches to the first host interface with a
default route.  However, when determining the host interface name the tests
implicitly select the *last* host interface: they use a jq expression which
will list all interfaces with default routes, but the way output detection
works in the scripts, it will only pick up the last line.

If there are multiple interfaces with default routes on the host, and they
each have a different address, this can cause spurious test failures.

Signed-off-by: David Gibson

tests: Handle the case of a nameserver on host localhost

2022-07-22T17:41:42+00:00

We previously introduced a change to passt to handle the case where the
host machine is its own nameserver - so resolv.conf points to 127.0.0.1.
In this case we advertize the gateway as the DNS server for the guest,
which in turn will be redirected back to the host by existing passt logic.

The dhcp/passt doesn't handle this case correctly, so add some logic to
account for it.

Signed-off-by: David Gibson

tests: More robust parsing of resolv.conf for DHCP tests

2022-07-22T17:41:42+00:00

To check publishing of DNS information via DHCP, we need to extract a list
of nameservers and/or search domains from resolv.conf in the test script.

The current version (usually) leaves the result with a trailing ','.
That's usually ok because it happens on both guest and host sides.  However
it's kind of confusing, and might stop working if the host had a
resolv.conf without a trailing \n on the last line.  It also makes some
later changes we'll need more difficult.

So, normalize the output from resolv.conf a bit further, removing any
trailing ','.  It turns out we can do this with a slightly less complex
sed expression than the one we already have.

Signed-off-by: David Gibson

tests: Explicitly list test files in test/run, remove "onlyfor" support

2022-07-13T23:32:42+00:00

Currently test/run uses wildcards to run all of the tests in a directory.
However, that wildcard list is filtered down by the "onlyfor" directives
in the test files... usually to a single file.

Therefore, just explicitly list the files we *really* want to run for this
test mode.  This makes it easier to see at the top level what tests will
be executed, and to change that list temporarily while debugging specific
failures.

This means the "onlyfor" directive no longer has any purpose, and we can
remove it.  "onlyfor" was also the only used of the $MODE variable, so we
can remove that too.

Signed-off-by: David Gibson

Use dhclient instead of udhcpc

2022-06-15T07:38:10+00:00

For some reason, the passt/pasta tests and examples use dhclient for
DHCPv6, but in most cases use udhcpc for DHCPv4.  Change it to use dhclient
for both DHCPv4 and DHCPv6.  This means one less tool we need for testing,
plus dhclient is easily available on Fedora whereas udhcpc is not.

Note that the passt tests still rely on udhcpc indirectly because mbuto
wants to put it into the guest images it generates.

Signed-off-by: David Gibson

Tweak dhclient arguments for readability

2022-06-15T07:38:10+00:00

A number of tests and examples use dhclient in both IPv4 and IPv6 modes.
We use "dhclient -6" for IPv6, but usually just "dhclient" for IPv4.  Add
an explicit "-4" argument to make it more clear and explicit.

In addition, when dhclient is run from within pasta it usually won't be
"real" root, and so will not have access to write the default global pid
file.  This results in a mostly harmless but irritating error:
    Can't create /var/run/dhclient.pid: Permission denied
We can avoid that by using the --no-pid flag to dhclient.

Signed-off-by: David Gibson

Don't abbreviate ip(8) arguments in examples and tests

2022-06-15T07:38:10+00:00

ip(8)'s ability to take abbreviated arguments (e.g. "li sh" instead of
"link show") is very handy when using it interactively, but it doesn't make
for very readable scripts and examples when shown that way.

Signed-off-by: David Gibson