From f8ec11482098b806732cae29278c44710318ba0d Mon Sep 17 00:00:00 2001
From: moneromooo <moneromoo@nowhere.nowhere.nowhere>
Date: Wed, 2 Dec 2020 19:36:08 +0000
Subject: [PATCH] keep only the last seen node on a given host in the white
 list

---
 contrib/epee/src/net_utils_base.cpp | 33 +++++++++++++++++++++++++++++
 src/p2p/net_peerlist.cpp            | 13 ++++++++++++
 src/p2p/net_peerlist.h              |  2 ++
 3 files changed, 48 insertions(+)

diff --git a/contrib/epee/src/net_utils_base.cpp b/contrib/epee/src/net_utils_base.cpp
index 5cc49cc71..6b2d27938 100644
--- a/contrib/epee/src/net_utils_base.cpp
+++ b/contrib/epee/src/net_utils_base.cpp
@@ -6,6 +6,17 @@
 #include "string_tools.h"
 #include "net/local_ip.h"
 
+static inline uint32_t make_address_v4_from_v6(const boost::asio::ip::address_v6& a)
+{
+  const auto &bytes = a.to_bytes();
+  uint32_t v4 = 0;
+  v4 = (v4 << 8) | bytes[12];
+  v4 = (v4 << 8) | bytes[13];
+  v4 = (v4 << 8) | bytes[14];
+  v4 = (v4 << 8) | bytes[15];
+  return htonl(v4);
+}
+
 namespace epee { namespace net_utils
 {
 	bool ipv4_network_address::equal(const ipv4_network_address& other) const noexcept
@@ -83,6 +94,28 @@ namespace epee { namespace net_utils
 		network_address::interface const* const other_self = other.self.get();
 		if (self_ == other_self) return true;
 		if (!self_ || !other_self) return false;
+		const bool this_is_4 = get_type_id() == epee::net_utils::ipv4_network_address::get_type_id();
+		const bool this_is_6 = get_type_id() == epee::net_utils::ipv6_network_address::get_type_id();
+		const bool other_is_4 = other.get_type_id() == epee::net_utils::ipv4_network_address::get_type_id();
+		const bool other_is_6 = other.get_type_id() == epee::net_utils::ipv6_network_address::get_type_id();
+		if (this_is_4 && other_is_6)
+		{
+			const boost::asio::ip::address_v6 &actual_ip = other.as<const epee::net_utils::ipv6_network_address>().ip();
+			if (actual_ip.is_v4_mapped())
+			{
+				const uint32_t v4ip = make_address_v4_from_v6(actual_ip);
+				return is_same_host(ipv4_network_address(v4ip, 0));
+			}
+		}
+		else if (this_is_6 && other_is_4)
+		{
+			const boost::asio::ip::address_v6 &actual_ip = this->as<const epee::net_utils::ipv6_network_address>().ip();
+			if (actual_ip.is_v4_mapped())
+			{
+				const uint32_t v4ip = make_address_v4_from_v6(actual_ip);
+				return other.is_same_host(ipv4_network_address(v4ip, 0));
+			}
+		}
 		if (typeid(*self_) != typeid(*other_self)) return false;
 		return self_->is_same_host(*other_self);
 	}
diff --git a/src/p2p/net_peerlist.cpp b/src/p2p/net_peerlist.cpp
index ce5c67fe5..42ab9727d 100644
--- a/src/p2p/net_peerlist.cpp
+++ b/src/p2p/net_peerlist.cpp
@@ -288,6 +288,19 @@ namespace nodetool
     copy_peers(peers.gray, m_peers_gray.get<by_addr>());
     copy_peers(peers.anchor, m_peers_anchor.get<by_addr>());
   }
+
+  void peerlist_manager::evict_host_from_white_peerlist(const peerlist_entry& pr)
+  {
+    peers_indexed::index<by_time>::type& sorted_index=m_peers_white.get<by_time>();
+    auto i = sorted_index.begin();
+    while (i != sorted_index.end())
+    {
+      if (i->adr.is_same_host(pr.adr))
+        i = sorted_index.erase(i);
+      else
+        ++i;
+    }
+  }
 }
 
 BOOST_CLASS_VERSION(nodetool::peerlist_types, nodetool::CURRENT_PEERLIST_STORAGE_ARCHIVE_VER);
diff --git a/src/p2p/net_peerlist.h b/src/p2p/net_peerlist.h
index 992462d0b..c794b0f3b 100644
--- a/src/p2p/net_peerlist.h
+++ b/src/p2p/net_peerlist.h
@@ -109,6 +109,7 @@ namespace nodetool
     bool get_white_peer_by_index(peerlist_entry& p, size_t i);
     bool get_gray_peer_by_index(peerlist_entry& p, size_t i);
     template<typename F> bool foreach(bool white, const F &f);
+    void evict_host_from_white_peerlist(const peerlist_entry& pr);
     bool append_with_peer_white(const peerlist_entry& pr);
     bool append_with_peer_gray(const peerlist_entry& pr);
     bool append_with_peer_anchor(const anchor_peerlist_entry& ple);
@@ -345,6 +346,7 @@ namespace nodetool
     if(by_addr_it_wt == m_peers_white.get<by_addr>().end())
     {
       //put new record into white list
+      evict_host_from_white_peerlist(ple);
       m_peers_white.insert(ple);
       trim_white_peerlist();
     }else