Change default for GuestIPMustBeZero when GuestIP is 0.0.0.0

[jandubois]

It now defaults to true. The user must explicitly set it to false to match any interface and not just 0.0.0.0.

This change is not backwards compatible!

Closes #4193

[norio-nomura]

When the guestIP is not specified, the bind to the loopback or unspecified can be accepted, but the binding to the other is rejected. Is it better to make it clear in the test?

Is it like this when they are covered?

$ git diff
diff --git a/hack/test-port-forwarding.pl b/hack/test-port-forwarding.pl
index bbd9eab2..4c586dbf 100755
--- a/hack/test-port-forwarding.pl
+++ b/hack/test-port-forwarding.pl
@@ -347,14 +347,41 @@ portForwards:
   # forward: ::        3032 → ipv4 2032
   # forward: ::1       3033 → ipv4 2033
 
-- guestPortRange: [300, 309]
+- guestPortRange: [300, 304]
 
-  # forward: 127.0.0.1 300 → 127.0.0.1 300
+  # forward: 127.0.0.1    300 → 127.0.0.1 300
+  # forward: 0.0.0.0      301 → 127.0.0.1 301
+  # forward: ::           302 → 127.0.0.1 302
+  # forward: ::1          303 → 127.0.0.1 303
+  # ignore:  192.168.5.15 304 → 127.0.0.1 304
 
-- guestPortRange: [310, 319]
+- guestPortRange: [305, 309]
+  guestIPMustBeZero: false
+
+  # forward: 127.0.0.1    325 → 127.0.0.1 325
+  # forward: 0.0.0.0      326 → 127.0.0.1 326
+  # forward: ::           327 → 127.0.0.1 327
+  # forward: ::1          328 → 127.0.0.1 328
+  # ignore:  192.168.5.15 329 → 127.0.0.1 329
+
+- guestPortRange: [310, 314]
+  hostIP: 0.0.0.0
+
+  # forward: 127.0.0.1    310 → 0.0.0.0 310
+  # forward: 0.0.0.0      311 → 0.0.0.0 311
+  # forward: ::           312 → 0.0.0.0 312
+  # forward: ::1          313 → 0.0.0.0 313
+  # ignore:  192.168.5.15 314 → 0.0.0.0 314
+
+- guestPortRange: [315, 319]
+  guestIPMustBeZero: false
   hostIP: 0.0.0.0
 
-  # forward: 127.0.0.1 310 → 0.0.0.0 310
+  # forward: 127.0.0.1    315 → 0.0.0.0 315
+  # forward: 0.0.0.0      316 → 0.0.0.0 316
+  # forward: ::           317 → 0.0.0.0 317
+  # forward: ::1          318 → 0.0.0.0 318
+  # ignore:  192.168.5.15 319 → 0.0.0.0 319
 
   # Things we can't test:
   # - Accessing a forward from a different interface (e.g. connect to ipv4 to connect to 0.0.0.0)
@@ -419,4 +446,21 @@ portForwards:
 - guestPort: 5000
   hostSocket: port5000.sock
 
-  # forward: 127.0.0.1 5000 → sockDir/port5000.sock
+  # forward: 127.0.0.1    5000 → sockDir/port5000.sock
+
+- guestPort: 5001
+  hostSocket: port5001.sock
+
+  # ignore:  192.168.5.15 5001 → sockDir/port5001.sock
+
+- guestPort: 5002
+  guestIPMustBeZero: false
+  hostSocket: port5002.sock
+
+  # forward: 127.0.0.1    5002 → sockDir/port5002.sock
+
+- guestPort: 5003
+  guestIPMustBeZero: false
+  hostSocket: port5003.sock
+
+  # ignore:  192.168.5.15 5003 → sockDir/port5003.sock

Maybe each intention should be written in some comments.

🤔 It may be necessary to make the rule parser possible for unit testing.