use customized rpc implementation, remove Tarpc & Tonic (#348)

This patch removes Tarpc & Tonic GRPC and implements a customized rpc framework, which can be used by peer rpc and cli interface.

web config server can also use this rpc framework.

moreover, rewrite the public server logic, use ospf route to implement public server based networking. this make public server mesh possible.

easytier/src/peer_center/mod.rs

@@ -5,9 +5,13 @@
 // peer center is not guaranteed to be stable and can be changed when peer enter or leave.
 // it's used to reduce the cost to exchange infos between peers.
 
+use std::collections::BTreeMap;
+
+use crate::proto::cli::PeerInfo;
+use crate::proto::peer_rpc::{DirectConnectedPeerInfo, PeerInfoForGlobalMap};
+
 pub mod instance;
 mod server;
-mod service;
 
 #[derive(thiserror::Error, Debug, serde::Deserialize, serde::Serialize)]
 pub enum Error {
@@ -18,3 +22,29 @@ pub enum Error {
 }
 
 pub type Digest = u64;
+
+impl From<Vec<PeerInfo>> for PeerInfoForGlobalMap {
+    fn from(peers: Vec<PeerInfo>) -> Self {
+        let mut peer_map = BTreeMap::new();
+        for peer in peers {
+            let Some(min_lat) = peer
+                .conns
+                .iter()
+                .map(|conn| conn.stats.as_ref().unwrap().latency_us)
+                .min()
+            else {
+                continue;
+            };
+
+            let dp_info = DirectConnectedPeerInfo {
+                latency_ms: std::cmp::max(1, (min_lat as u32 / 1000) as i32),
+            };
+
+            // sort conn info so hash result is stable
+            peer_map.insert(peer.peer_id, dp_info);
+        }
+        PeerInfoForGlobalMap {
+            direct_peers: peer_map,
+        }
+    }
+}