add DnsConfig and ZoneConfig with proto definitions

easytier/src/proto/dns.rs

@@ -0,0 +1,34 @@
+use std::fmt::Display;
+
+include!(concat!(env!("OUT_DIR"), "/dns.rs"));
+
+impl Display for ZoneConfigPb {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        writeln!(f, "; EasyTier Magic DNS zone file")?;
+        writeln!(f, "; https://github.com/easytier/easytier")?;
+
+        if !self.forwarders.is_empty() {
+            writeln!(f, "; Forwarders:")?;
+            for forwarder in &self.forwarders {
+                writeln!(f, "; \t{}", forwarder)?;
+            }
+        }
+        writeln!(f)?;
+
+        write!(f, "$ORIGIN {}", self.origin)?;
+        if !self.origin.ends_with('.') {
+            write!(f, ".")?;
+        }
+        writeln!(f)?;
+
+        writeln!(f, "$TTL {}", self.ttl)?;
+
+        writeln!(f)?;
+
+        for record in &self.records {
+            writeln!(f, "{}", record)?;
+        }
+
+        Ok(())
+    }
+}