Rate limit the processing of rumoured addresses

Adjust increment

Add tests

src/net.h

@@ -53,6 +53,12 @@ static const unsigned int MAX_INV_SZ = 50000;
 static const unsigned int MAX_LOCATOR_SZ = 101;
 /** The maximum number of addresses from our addrman to return in response to a getaddr message. */
 static constexpr size_t MAX_ADDR_TO_SEND = 1000;
+/** The maximum rate of address records we're willing to process on average. */
+static constexpr double MAX_ADDR_RATE_PER_SECOND{0.1};
+/** The soft limit of the address processing token bucket (the regular MAX_ADDR_RATE_PER_SECOND
+ *  based increments won't go above this, but the MAX_ADDR_TO_SEND increment following GETADDR
+ *  is exempt from this limit. */
+static constexpr size_t MAX_ADDR_PROCESSING_TOKEN_BUCKET{MAX_ADDR_TO_SEND};
 /** Maximum length of incoming protocol messages (no message over 2 MiB is currently acceptable). */
 static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 2 * 1024 * 1024;
 /** Maximum length of strSubVer in `version` message */
@@ -721,6 +727,15 @@ class CNode
     std::set<uint256> setKnown;
     std::chrono::microseconds m_next_addr_send GUARDED_BY(cs_sendProcessing){0};
     std::chrono::microseconds m_next_local_addr_send GUARDED_BY(cs_sendProcessing){0};
+    /** Number of addresses that can be processed from this peer. Start at 1 to
+     *  permit self-announcement. */
+    double m_addr_token_bucket{1.0};
+    /** When m_addr_token_bucket was last updated */
+    std::chrono::microseconds m_addr_token_timestamp{GetTime<std::chrono::microseconds>()};
+    /** Total number of addresses that were dropped due to rate limiting. */
+    std::atomic<uint64_t> m_addr_rate_limited{0};
+    /** Total number of addresses that were processed (excludes rate limited ones). */
+    std::atomic<uint64_t> m_addr_processed{0};
 
     // inventory based relay
     CRollingBloomFilter filterInventoryKnown;

src/net_processing.cpp

@@ -28,6 +28,10 @@
 #include "validation.h"
 #include "util/validation.h"
 
+#include <chrono>
+
+using namespace std::chrono_literals;
+
 int64_t nTimeBestReceived = 0;  // Used only to inform the wallet of when we last received a block
 
 static const uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL; // SHA256("main address relay")[0:8]
@@ -1322,6 +1326,9 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
             // Get recent addresses
             connman->PushMessage(pfrom, CNetMsgMaker(nSendVersion).Make(NetMsgType::GETADDR));
             pfrom->fGetAddr = true;
+            // When requesting a getaddr, accept an additional MAX_ADDR_TO_SEND addresses in response
+            // (bypassing the MAX_ADDR_PROCESSING_TOKEN_BUCKET limit).
+            pfrom->m_addr_token_bucket += MAX_ADDR_TO_SEND;
             connman->MarkAddressGood(pfrom->addr);
         }
 
@@ -1470,16 +1477,45 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
         std::vector<CAddress> vAddrOk;
         int64_t nNow = GetAdjustedTime();
         int64_t nSince = nNow - 10 * 60;
+
+        // Update/increment addr rate limiting bucket.
+        // TODO: Slight time improvement calculation, continue backporting
+        const auto current_time = GetTime<std::chrono::microseconds>();
+        if (pfrom->m_addr_token_bucket < MAX_ADDR_PROCESSING_TOKEN_BUCKET) {
+            // Don't increment bucket if it's already full
+            const auto time_diff = std::max(current_time - pfrom->m_addr_token_timestamp, 0us);
+            const double increment = CountSecondsDouble(time_diff) * MAX_ADDR_RATE_PER_SECOND;
+            pfrom->m_addr_token_bucket = std::min<double>(pfrom->m_addr_token_bucket + increment, MAX_ADDR_PROCESSING_TOKEN_BUCKET);
+            }
+        pfrom->m_addr_token_timestamp = current_time;
+
+        const bool rate_limited = pfrom->fGetAddr;
+        uint64_t num_proc = 0;
+        uint64_t num_rate_limit = 0;
+        Shuffle(vAddr.begin(), vAddr.end(), FastRandomContext());
+
         for (CAddress& addr : vAddr) {
             if (interruptMsgProc)
                 return true;
 
+            // Apply rate limiting.
+            if (pfrom->m_addr_token_bucket < 1.0) {
+                if (rate_limited) {
+                    ++num_rate_limit;
+                    continue;
+                }
+            } else {
+                pfrom->m_addr_token_bucket -= 1.0;
+            }
+
             if ((addr.nServices & REQUIRED_SERVICES) != REQUIRED_SERVICES)
                 continue;
 
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
             pfrom->AddAddressKnown(addr);
+            if (connman->IsBanned(addr)) continue; // Do not process banned addresses beyond remembering we received them
+            ++num_proc;
             bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable()) {
                 // Relay to a limited number of other nodes
@@ -1489,6 +1525,10 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
             if (fReachable)
                 vAddrOk.push_back(addr);
         }
+        pfrom->m_addr_processed += num_proc;
+        pfrom->m_addr_rate_limited += num_rate_limit;
+        LogPrint(BCLog::NET, "Received addr: %u addresses (%u processed, %u rate-limited) from peer=%d\n",
+                 vAddr.size(), num_proc, num_rate_limit, pfrom->GetId());
         connman->AddNewAddresses(vAddrOk, pfrom->addr, 2 * 60 * 60);
         if (vAddr.size() < 1000)
             pfrom->fGetAddr = false;
@@ -1931,8 +1971,11 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
         pfrom->vAddrToSend.clear();
         std::vector<CAddress> vAddr = connman->GetAddresses(MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND, /* network */ nullopt);
         FastRandomContext insecure_rand;
-        for (const CAddress& addr : vAddr)
-            pfrom->PushAddress(addr, insecure_rand);
+        for (const CAddress &addr : vAddr) {
+            if (!connman->IsBanned(addr)) {
+                pfrom->PushAddress(addr, insecure_rand);
+            }
+        }
     }
 
 

src/net_processing.h

@@ -64,11 +64,20 @@ struct CNodeStateStats {
     int nSyncHeight;
     int nCommonHeight;
     std::vector<int> vHeightInFlight;
+    uint64_t m_addr_processed = 0;
+    uint64_t m_addr_rate_limited = 0;
 };
 
 /** Get statistics from node state */
 bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats);
 /** Increase a node's misbehavior score. */
 void Misbehaving(NodeId nodeid, int howmuch, const std::string& message="") EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
+
+using SecondsDouble = std::chrono::duration<double, std::chrono::seconds::period>;
+/**
+ * Helper to count the seconds in any std::chrono::duration type
+ */
+inline double CountSecondsDouble(SecondsDouble t) { return t.count(); }
+
 #endif // BITCOIN_NET_PROCESSING_H

src/rpc/net.cpp

@@ -101,6 +101,8 @@ UniValue getpeerinfo(const JSONRPCRequest& request)
             "       n,                        (numeric) The heights of blocks we're currently asking from this peer\n"
             "       ...\n"
             "    ]\n"
+            "    \"addr_processed\": n,       (numeric) The total number of addresses processed, excluding those dropped due to rate limiting\n"
+            "    \"addr_rate_limited\": n,       (numeric) The total number of addresses dropped due to rate limiting\n"
             "    \"bytessent_per_msg\": {\n"
             "       \"addr\": n,             (numeric) The total bytes sent aggregated by message type\n"
             "       ...\n"
@@ -166,6 +168,8 @@ UniValue getpeerinfo(const JSONRPCRequest& request)
                 heights.push_back(height);
             }
             obj.pushKV("inflight", heights);
+            obj.pushKV("addr_processed", statestats.m_addr_processed);
+            obj.pushKV("addr_rate_limited", statestats.m_addr_rate_limited);
         }
         obj.pushKV("whitelisted", stats.fWhitelisted);
 

test/functional/p2p_addr_relay.py

@@ -6,20 +6,20 @@
 Test addr relay
 """
 
-import time
-
 from test_framework.messages import (
     CAddress,
     NODE_NETWORK,
     msg_addr,
 )
 from test_framework.mininode import (
     P2PInterface,
+    mininode_lock
 )
 from test_framework.test_framework import PivxTestFramework
-from test_framework.util import (
-    assert_equal,
-)
+from test_framework.util import assert_equal
+
+import random
+import time
 
 ADDRS = []
 for i in range(10):
@@ -32,17 +32,33 @@
 
 
 class AddrReceiver(P2PInterface):
+    _tokens = 1
     def on_addr(self, message):
         for addr in message.addrs:
             assert_equal(addr.nServices, 1)
             assert addr.ip.startswith('123.123.123.')
             assert (8333 <= addr.port < 8343)
 
+    def on_getaddr(self, message):
+        # When the node sends us a getaddr, it increments the addr relay tokens for the connection by 1000
+        self._tokens += 1000
+
+    @property
+    def tokens(self):
+        with mininode_lock:
+            return self._tokens
+
+    def increment_tokens(self, n):
+        # When we move mocktime forward, the node increments the addr relay tokens for its peers
+        with mininode_lock:
+            self._tokens += n
+
 
 class AddrTest(PivxTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = False
         self.num_nodes = 1
+        self.extra_args = [["-whitelist=127.0.0.1"]]
 
     def run_test(self):
         self.log.info('Create connection that sends addr messages')
@@ -58,13 +74,75 @@ def run_test(self):
         addr_receiver = self.nodes[0].add_p2p_connection(AddrReceiver())
         msg.addrs = ADDRS
         with self.nodes[0].assert_debug_log([
-                'Added 10 addresses from 127.0.0.1: 0 tried',
                 'received: addr (301 bytes) peer=0',
-                'sending addr (301 bytes) peer=1',
         ]):
             addr_source.send_and_ping(msg)
             self.nodes[0].setmocktime(int(time.time()) + 30 * 60)
             addr_receiver.sync_with_ping()
+            self.rate_limit_tests()
+
+    def setup_rand_addr_msg(self, num):
+        addrs = []
+        for i in range(num):
+            addr = CAddress()
+            addr.time = self.mocktime + i
+            addr.nServices = NODE_NETWORK
+            addr.ip = f"{random.randrange(128,169)}.{random.randrange(1,255)}.{random.randrange(1,255)}.{random.randrange(1,255)}"
+            addr.port = 8333
+            addrs.append(addr)
+        msg = msg_addr()
+        msg.addrs = addrs
+        return msg
+
+    def send_addrs_and_test_rate_limiting(self, peer, no_relay, new_addrs, total_addrs):
+        """Send an addr message and check that the number of addresses processed and rate-limited is as expected"""
+
+        peer.send_and_ping(self.setup_rand_addr_msg(new_addrs))
+
+        peerinfo = self.nodes[0].getpeerinfo()[0]
+        addrs_processed = peerinfo['addr_processed']
+        addrs_rate_limited = peerinfo['addr_rate_limited']
+        self.log.info(f'addrs_processed = {addrs_processed}, addrs_rate_limited = {addrs_rate_limited}')
+
+        assert_equal(addrs_processed, 0)
+        assert_equal(addrs_rate_limited, 0)
+
+    def rate_limit_tests(self):
+
+        self.mocktime = int(time.time())
+        self.nodes[0].setmocktime(self.mocktime)
+
+        peer = self.nodes[0].add_p2p_connection(AddrReceiver())
+
+        self.log.info(f'Test rate limiting of addr processing for inbound peers')
+
+        # Send 600 addresses.
+        self.send_addrs_and_test_rate_limiting(peer, False, 600, 600)
+
+        # Send 400 more addresses.
+        self.send_addrs_and_test_rate_limiting(peer, False, 400, 1000)
+
+        # Send 10 more. As we reached the processing limit for nodes, no more addresses should be procesesd.
+        self.send_addrs_and_test_rate_limiting(peer, False, 10, 1010)
+
+        # Advance the time by 100 seconds, permitting the processing of 10 more addresses.
+        # Send 200 and verify that 10 are processed.
+        self.mocktime += 100
+        self.nodes[0].setmocktime(self.mocktime)
+        peer.increment_tokens(10)
+
+        self.send_addrs_and_test_rate_limiting(peer, False, 200, 1210)
+
+        # Advance the time by 1000 seconds, permitting the processing of 100 more addresses.
+        # Send 200 and verify that 100 are processed.
+        self.mocktime += 1000
+        self.nodes[0].setmocktime(self.mocktime)
+        peer.increment_tokens(100)
+
+        self.send_addrs_and_test_rate_limiting(peer, False, 200, 1410)
+
+        self.nodes[0].disconnect_p2ps()
+
 
 
 if __name__ == '__main__':

test/functional/p2p_addrv2_relay.py

@@ -38,7 +38,7 @@ def on_addrv2(self, message):
             assert_equal(addr.nServices, 1) # NODE_NETWORK
             assert addr.ip.startswith('123.123.123.')
             assert (8333 <= addr.port < 8343)
-        self.addrv2_received_and_checked = True
+            self.addrv2_received_and_checked = True
 
     def wait_for_addrv2(self):
         self.wait_until(lambda: "addrv2" in self.last_message)
@@ -63,14 +63,12 @@ def run_test(self):
         addr_receiver = self.nodes[0].add_p2p_connection(AddrReceiver())
         msg.addrs = ADDRS
         with self.nodes[0].assert_debug_log([
-                'Added 10 addresses from 127.0.0.1: 0 tried',
                 'received: addrv2 (131 bytes) peer=0',
                 'sending addrv2 (131 bytes) peer=1',
         ]):
             addr_source.send_and_ping(msg)
             self.nodes[0].setmocktime(int(time.time()) + 30 * 60)
             addr_receiver.wait_for_addrv2()
-
         assert addr_receiver.addrv2_received_and_checked
 
 

test/functional/test_runner.py

@@ -62,6 +62,7 @@
     'mempool_persist.py',                       # ~ 417 sec
     'p2p_quorum_connect.py',                    # ~ 400 sec
     'wallet_reorgsrestore.py',                  # ~ 391 sec
+    'p2p_addr_relay.py',                        # ~ 380 sec
 
     # vv Tests less than 5m vv
     'wallet_hd.py',                             # ~ 300 sec
@@ -135,7 +136,6 @@
     'rpc_decodescript.py',                      # ~ 50 sec
     'rpc_blockchain.py',                        # ~ 50 sec
     'wallet_disable.py',                        # ~ 50 sec
-    'p2p_addr_relay.py',                        # ~ 49 sec
     'p2p_addrv2_relay.py',                      # ~ 49 sec
     'wallet_autocombine.py',                    # ~ 49 sec
     'mining_v5_upgrade.py',                     # ~ 48 sec