ab/tsunagi
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Warn about a zone name only when it collides with something

Browse Source 
"`.pidar` is not a delegated top-level domain today, but it could become
one" fired on every private name anybody has ever picked, which is every
network without a dot in its name. A warning that is always there is a
warning about nothing, and it teaches people to skim past the ones that
mean something — there were two of them in one report, side by side with
the real checks.

What is left is the collision that exists: a name that really is a public
top-level domain, which does make every public name under it unreachable
from that host, and `.local`, which belongs to multicast DNS. A name that
shadows nothing is said nothing about.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
tsunagi
2026-09-22 02:09:17 +01:00
co-authored by Claude Opus 5
parent 83d3445b7e
commit 458051f47d
2 changed files with 19 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files
README.md
+6 -5
View File
@@ -251,11 +251,12 @@ for the host running the agent, and binding an overlay address would put
them in front of the whole mesh — an agent in two networks would then answer
one network's questions about the other's names.
The zone is the network name unless `--dns-zone` says otherwise. It is
yours to choose, so a name that shadows a real public domain is reported and
then used: `--dns-zone ru` warns that every public `.ru` name becomes
unreachable from this host, and then does it. `.internal` is reserved for
exactly this and is never mentioned.
The zone is the network name, and it is yours to choose. A name that
shadows a real public domain is reported and then used: a network called
`ru` warns that every public `.ru` name becomes unreachable from this host,
and then does it. Anything that collides with nothing — which is most names
— is said nothing about, because a warning that fires on every private name
anybody picks is how people learn to ignore warnings.
On Linux the agent tells systemd-resolved to send questions for that suffix
here, over D-Bus, scoped to the overlay interface and as a *routing* domain
crates/tsunagi/src/dns/zone.rs
+13 -14
View File
@@ -128,17 +128,14 @@ impl ZoneName {
.to_string(),
);
}
if tld::exist_case_insensitive(top) {
return Some(format!(
// A real top-level domain is the whole of it. A name that is not
// delegated today might be one day — and saying so fires on every
// private name anybody ever picks, which is a warning about
// nothing that teaches people to ignore warnings.
tld::exist_case_insensitive(top).then(|| {
format!(
"`.{top}` is a real top-level domain, so every public name under it \
becomes unreachable from this host while the overlay is up"
));
}
// Not delegated today is not a promise about tomorrow.
(!self.0.contains('.')).then(|| {
format!(
"`.{top}` is not a delegated top-level domain today, but it could \
become one; `.internal` is reserved for private use and never will"
)
})
}
@@ -516,11 +513,13 @@ mod tests {
let local = ZoneName::new("local").unwrap().collision().unwrap();
assert!(local.contains("multicast DNS"), "{local}");
// An undelegated single label is a maybe, not a yes.
let lab = ZoneName::new("lab").unwrap().collision().unwrap();
assert!(lab.contains("could"), "{lab}");
// A multi-label name under something undelegated is not worth a word.
assert_eq!(ZoneName::new("a.lab").unwrap().collision(), None);
// A name that collides with nothing is said nothing about. It
// might be delegated one day, and warning about that fires on
// every private name anybody picks — a warning about nothing,
// which is how people learn to ignore warnings.
for quiet in ["lab", "a.lab", "pidar", "twar", "kitchen-table"] {
assert_eq!(ZoneName::new(quiet).unwrap().collision(), None, "{quiet}");
}
}
#[test]