net: Add continuous ASMap health check logging

Author: fjahr

src/net.cpp

@@ -3305,6 +3305,12 @@ bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
     // Dump network addresses
     scheduler.scheduleEvery([this] { DumpAddresses(); }, DUMP_PEERS_INTERVAL);
 
+    // Run the ASMap Health check once and then schedule it to run every 24h.
+    if (m_netgroupman.UsingASMap()) {
+        ASMapHealthCheck();
+        scheduler.scheduleEvery([this] { ASMapHealthCheck(); }, ASMAP_HEALTH_CHECK_INTERVAL);
+    }
+
     return true;
 }
 
@@ -3853,6 +3859,19 @@ void CConnman::PerformReconnections()
     }
 }
 
+void CConnman::ASMapHealthCheck()
+{
+    const std::vector<CAddress> v4_addrs{GetAddresses(/*max_addresses=*/ 0, /*max_pct=*/ 0, Network::NET_IPV4, /*filtered=*/ false)};
+    const std::vector<CAddress> v6_addrs{GetAddresses(/*max_addresses=*/ 0, /*max_pct=*/ 0, Network::NET_IPV6, /*filtered=*/ false)};
+    std::vector<CNetAddr> clearnet_addrs;
+    clearnet_addrs.reserve(v4_addrs.size() + v6_addrs.size());
+    std::transform(v4_addrs.begin(), v4_addrs.end(), std::back_inserter(clearnet_addrs),
+        [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
+    std::transform(v6_addrs.begin(), v6_addrs.end(), std::back_inserter(clearnet_addrs),
+        [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
+    m_netgroupman.ASMapHealthCheck(clearnet_addrs);
+}
+
 // Dump binary message to file, with timestamp.
 static void CaptureMessageToFile(const CAddress& addr,
                                  const std::string& msg_type,

src/net.h

@@ -87,6 +87,8 @@ static const bool DEFAULT_BLOCKSONLY = false;
 static const int64_t DEFAULT_PEER_CONNECT_TIMEOUT = 60;
 /** Number of file descriptors required for message capture **/
 static const int NUM_FDS_MESSAGE_CAPTURE = 1;
+/** Interval for ASMap Health Check **/
+static constexpr std::chrono::hours ASMAP_HEALTH_CHECK_INTERVAL{24};
 
 static constexpr bool DEFAULT_FORCEDNSSEED{false};
 static constexpr bool DEFAULT_DNSSEED{true};
@@ -1138,6 +1140,7 @@ class CConnman
     void SetNetworkActive(bool active);
     void OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant&& grant_outbound, const char* strDest, ConnectionType conn_type, bool use_v2transport) EXCLUSIVE_LOCKS_REQUIRED(!m_unused_i2p_sessions_mutex);
     bool CheckIncomingNonce(uint64_t nonce);
+    void ASMapHealthCheck();
 
     // alias for thread safety annotations only, not defined
     RecursiveMutex& GetNodesMutex() const LOCK_RETURNED(m_nodes_mutex);

src/netgroup.cpp

@@ -5,6 +5,7 @@
 #include <netgroup.h>
 
 #include <hash.h>
+#include <logging.h>
 #include <util/asmap.h>
 
 uint256 NetGroupManager::GetAsmapChecksum() const
@@ -109,3 +110,23 @@ uint32_t NetGroupManager::GetMappedAS(const CNetAddr& address) const
     uint32_t mapped_as = Interpret(m_asmap, ip_bits);
     return mapped_as;
 }
+
+void NetGroupManager::ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const {
+    std::set<uint32_t> clearnet_asns{};
+    int unmapped_count{0};
+
+    for (const auto& addr : clearnet_addrs) {
+        uint32_t asn = GetMappedAS(addr);
+        if (asn == 0) {
+            ++unmapped_count;
+            continue;
+        }
+        clearnet_asns.insert(asn);
+    }
+
+    LogPrintf("ASMap Health Check: %i clearnet peers are mapped to %i ASNs with %i peers being unmapped\n", clearnet_addrs.size(), clearnet_asns.size(), unmapped_count);
+}
+
+bool NetGroupManager::UsingASMap() const {
+    return m_asmap.size() > 0;
+}

src/netgroup.h

@@ -41,6 +41,16 @@ class NetGroupManager {
      */
     uint32_t GetMappedAS(const CNetAddr& address) const;
 
+    /**
+     *  Analyze and log current health of ASMap based buckets.
+     */
+    void ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const;
+
+    /**
+     *  Indicates whether ASMap is being used for clearnet bucketing.
+     */
+    bool UsingASMap() const;
+
 private:
     /** Compressed IP->ASN mapping, loaded from a file when a node starts.
      *

test/functional/feature_asmap.py

@@ -111,6 +111,14 @@ def test_empty_asmap(self):
         self.node.assert_start_raises_init_error(extra_args=['-asmap'], expected_msg=msg)
         os.remove(self.default_asmap)
 
+    def test_asmap_health_check(self):
+        self.log.info('Test bitcoind -asmap logs ASMap Health Check with basic stats')
+        shutil.copyfile(self.asmap_raw, self.default_asmap)
+        msg = "ASMap Health Check: 2 clearnet peers are mapped to 1 ASNs with 0 peers being unmapped"
+        with self.node.assert_debug_log(expected_msgs=[msg]):
+            self.start_node(0, extra_args=['-asmap'])
+        os.remove(self.default_asmap)
+
     def run_test(self):
         self.node = self.nodes[0]
         self.datadir = self.node.chain_path
@@ -124,6 +132,7 @@ def run_test(self):
         self.test_asmap_interaction_with_addrman_containing_entries()
         self.test_default_asmap_with_missing_file()
         self.test_empty_asmap()
+        self.test_asmap_health_check()
 
 
 if __name__ == '__main__':