From f39fbb2ce254c0209a63f5b204665d1d2cadc99c Mon Sep 17 00:00:00 2001
From: "Sijie.Sun" <sunsijie@buaa.edu.cn>
Date: Sun, 8 Jun 2025 11:28:59 +0800
Subject: [PATCH] ipv4-peerid table should use peer with least hop (#958)

sometimes route table may not be updated in time, so some dead nodes are still showing in the peer list.
when generating ipv4-peer table, we should avoid these dead devices overrides the entry of healthy nodes.
---
 easytier/src/instance/virtual_nic.rs  | 11 +++++-----
 easytier/src/peers/peer_ospf_route.rs | 29 +++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/easytier/src/instance/virtual_nic.rs b/easytier/src/instance/virtual_nic.rs
index 029a6b6..b11342d 100644
--- a/easytier/src/instance/virtual_nic.rs
+++ b/easytier/src/instance/virtual_nic.rs
@@ -1,4 +1,5 @@
 use std::{
+    collections::BTreeSet,
     io,
     net::Ipv4Addr,
     pin::Pin,
@@ -569,26 +570,26 @@ impl NicCtx {
         let ifname = nic.ifname().to_owned();
 
         self.tasks.spawn(async move {
-            let mut cur_proxy_cidrs = vec![];
+            let mut cur_proxy_cidrs = BTreeSet::new();
             loop {
-                let mut proxy_cidrs = vec![];
+                let mut proxy_cidrs = BTreeSet::new();
                 let routes = peer_mgr.list_routes().await;
                 for r in routes {
                     for cidr in r.proxy_cidrs {
                         let Ok(cidr) = cidr.parse::<cidr::Ipv4Cidr>() else {
                             continue;
                         };
-                        proxy_cidrs.push(cidr);
+                        proxy_cidrs.insert(cidr);
                     }
                 }
                 // add vpn portal cidr to proxy_cidrs
                 if let Some(vpn_cfg) = global_ctx.config.get_vpn_portal_config() {
-                    proxy_cidrs.push(vpn_cfg.client_cidr);
+                    proxy_cidrs.insert(vpn_cfg.client_cidr);
                 }
 
                 if let Some(routes) = global_ctx.config.get_routes() {
                     // if has manual routes, just override entire proxy_cidrs
-                    proxy_cidrs = routes;
+                    proxy_cidrs = routes.into_iter().collect();
                 }
 
                 // if route is in cur_proxy_cidrs but not in proxy_cidrs, delete it.
diff --git a/easytier/src/peers/peer_ospf_route.rs b/easytier/src/peers/peer_ospf_route.rs
index 704ad03..6768b26 100644
--- a/easytier/src/peers/peer_ospf_route.rs
+++ b/easytier/src/peers/peer_ospf_route.rs
@@ -854,11 +854,36 @@ impl RouteTable {
 
             self.peer_infos.insert(*peer_id, info.clone());
 
+            let is_new_peer_better = |old_peer_id: PeerId| -> bool {
+                let old_next_hop = self.get_next_hop(old_peer_id);
+                let new_next_hop = item.value();
+                old_next_hop.is_none()
+                    || new_next_hop.path_latency < old_next_hop.unwrap().path_latency
+            };
+
             if let Some(ipv4_addr) = info.ipv4_addr {
-                self.ipv4_peer_id_map.insert(ipv4_addr.into(), *peer_id);
+                self.ipv4_peer_id_map
+                    .entry(ipv4_addr.into())
+                    .and_modify(|v| {
+                        if *v != *peer_id && is_new_peer_better(*v) {
+                            self.ipv4_peer_id_map.insert(ipv4_addr.into(), *peer_id);
+                        }
+                    })
+                    .or_insert(*peer_id);
             }
 
             for cidr in info.proxy_cidrs.iter() {
+                self.cidr_peer_id_map
+                    .entry(cidr.parse().unwrap())
+                    .and_modify(|v| {
+                        if *v != *peer_id && is_new_peer_better(*v) {
+                            // if the next hop is not set or the new next hop is better, update it.
+                            self.cidr_peer_id_map
+                                .insert(cidr.parse().unwrap(), *peer_id);
+                        }
+                    })
+                    .or_insert(*peer_id);
+
                 self.cidr_peer_id_map
                     .insert(cidr.parse().unwrap(), *peer_id);
             }
@@ -1363,7 +1388,7 @@ impl PeerRouteServiceImpl {
                 .dst_saved_conn_bitmap_version
                 .get(&peer_id)
                 .map(|item| item.get());
-            if Some(*local_version) != peer_version {
+            if peer_version.is_none() || peer_version.unwrap() < *local_version {
                 need_update = true;
                 break;
             }