add DnsConfig and ZoneConfig with proto definitions

easytier/src/proto/dns.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+import "common.proto";
+
+package dns;
+
+enum DnsConfigKind {
+  LOCAL = 0;
+  REMOTE = 1;
+}
+
+message DnsConfigPb {
+  DnsConfigKind kind = 1;
+  repeated ZoneConfigPb zones = 2;
+  string name = 3;
+  string domain = 4;
+  repeated common.SocketAddr addresses = 5;
+  repeated string listeners = 6;
+}
+
+message ZoneConfigPb {
+  string origin = 1;
+  uint32 ttl = 2;
+  repeated string records = 3;
+  repeated string forwarders = 4;
+}

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(())
+    }
+}

easytier/src/proto/mod.rs

@@ -4,6 +4,8 @@ pub mod rpc_types;
 pub mod acl;
 pub mod api;
 pub mod common;
+#[cfg(feature = "magic-dns")]
+pub mod dns;
 pub mod error;
 #[cfg(feature = "magic-dns")]
 pub mod magic_dns;