utils: move to a mod

easytier/src/dns/utils/mod.rs

@@ -0,0 +1,43 @@
+use hickory_proto::rr::LowerName;
+use idna::AsciiDenyList;
+use itertools::Itertools;
+
+pub mod addr;
+pub mod authority;
+pub mod dirty;
+
+pub fn sanitize(name: &str) -> String {
+    let dot = name.ends_with('.');
+    let mut name = idna::domain_to_ascii_cow(name.as_ref(), AsciiDenyList::EMPTY)
+        .unwrap_or_default()
+        .into_owned()
+        .to_lowercase()
+        .split('.')
+        .map(|label| {
+            label
+                .chars()
+                .map(|c| if c.is_ascii_alphanumeric() { c } else { '-' })
+                .take(63)
+                .collect::<String>()
+                .trim_matches('-')
+                .to_string()
+        })
+        .filter(|label| !label.is_empty())
+        .collect_vec()
+        .join(".");
+    name.truncate(253);
+    if dot {
+        name.push('.');
+    }
+    name
+}
+
+pub fn parse(name: &str) -> LowerName {
+    if let Ok(name) = name.parse() {
+        name
+    } else {
+        let sanitized = sanitize(name);
+        tracing::debug!("invalid hostname: {}, sanitized to: {}", name, sanitized);
+        sanitized.parse().unwrap_or_default()
+    }
+}