backport: Merge bitcoin#28172, 28649, 28464

src/init.cpp

@@ -611,7 +611,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-forcednsseed", strprintf("Always query for peer addresses via DNS lookup (default: %u)", DEFAULT_FORCEDNSSEED), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-listen", strprintf("Accept connections from outside (default: %u if no -proxy, -connect or -maxconnections=0)", DEFAULT_LISTEN), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-listenonion", strprintf("Automatically create Tor onion service (default: %d)", DEFAULT_LISTEN_ONION), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    argsman.AddArg("-maxconnections=<n>", strprintf("Maintain at most <n> connections to peers (temporary service connections excluded) (default: %u). This limit does not apply to connections manually added via -addnode or the addnode RPC, which have a separate limit of %u.", DEFAULT_MAX_PEER_CONNECTIONS, MAX_ADDNODE_CONNECTIONS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-maxconnections=<n>", strprintf("Maintain at most <n> automatic connections to peers (temporary service connections excluded) (default: %u). This limit does not apply to connections manually added via -addnode or the addnode RPC, which have a separate limit of %u.", DEFAULT_MAX_PEER_CONNECTIONS, MAX_ADDNODE_CONNECTIONS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxreceivebuffer=<n>", strprintf("Maximum per-connection receive buffer, <n>*1000 bytes (default: %u)", DEFAULT_MAXRECEIVEBUFFER), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxsendbuffer=<n>", strprintf("Maximum per-connection memory usage for the send buffer, <n>*1000 bytes (default: %u)", DEFAULT_MAXSENDBUFFER), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxtimeadjustment", strprintf("Maximum allowed median peer time offset adjustment. Local perspective of time may be influenced by outbound peers forward or backward by this amount (default: %u seconds).", DEFAULT_MAX_TIME_ADJUSTMENT), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
@@ -2550,12 +2550,8 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
 
     CConnman::Options connOptions;
     connOptions.nLocalServices = nLocalServices;
-    connOptions.nMaxConnections = nMaxConnections;
-    connOptions.m_max_outbound_full_relay = std::min(MAX_OUTBOUND_FULL_RELAY_CONNECTIONS, connOptions.nMaxConnections);
-    connOptions.m_max_outbound_block_relay = std::min(MAX_BLOCK_RELAY_ONLY_CONNECTIONS, connOptions.nMaxConnections-connOptions.m_max_outbound_full_relay);
-    connOptions.m_max_outbound_onion = std::min(MAX_DESIRED_ONION_CONNECTIONS, connOptions.nMaxConnections / 2);
-    connOptions.nMaxAddnode = MAX_ADDNODE_CONNECTIONS;
-    connOptions.nMaxFeeler = MAX_FEELER_CONNECTIONS;
+    connOptions.m_max_outbound_onion = std::min(MAX_DESIRED_ONION_CONNECTIONS, connOptions.m_max_automatic_connections / 2);
+    connOptions.m_max_automatic_connections = nMaxConnections;
     connOptions.uiInterface = &uiInterface;
     connOptions.m_banman = node.banman.get();
     connOptions.m_msgproc = node.peerman.get();

src/net.cpp

@@ -1880,7 +1880,6 @@ void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
 {
     int nInbound = 0;
     int nVerifiedInboundMasternodes = 0;
-    int nMaxInbound = nMaxConnections - m_max_outbound;
 
     AddWhitelistPermissionFlags(permission_flags, addr);
     if (NetPermissions::HasFlag(permission_flags, NetPermissionFlags::Implicit)) {
@@ -1939,7 +1938,7 @@ void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
 
     // Only accept connections from discouraged peers if our inbound slots aren't (almost) full.
     bool discouraged = m_banman && m_banman->IsDiscouraged(addr);
-    if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && nInbound + 1 >= nMaxInbound && discouraged)
+    if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && nInbound + 1 >= m_max_inbound && discouraged)
     {
         LogPrint(BCLog::NET_NETCONN, "connection from %s dropped (discouraged)\n", addr.ToStringAddrPort());
         return;
@@ -1950,7 +1949,7 @@ void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
     // We don't evict verified MN connections and also don't take them into account when checking limits. We can do this
     // because we know that such connections are naturally limited by the total number of MNs, so this is not usable
     // for attacks.
-    while (nInbound - nVerifiedInboundMasternodes >= nMaxInbound)
+    while (nInbound - nVerifiedInboundMasternodes >= m_max_inbound)
     {
         if (!AttemptToEvictConnection()) {
             // No connection to evict, disconnect the new connection
@@ -3270,7 +3269,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect, CDe
             // different netgroups in ipv4/ipv6 networks + all peers in Tor/I2P/CJDNS networks.
             // Don't record addrman failure attempts when node is offline. This can be identified since all local
             // network connections (if any) belong in the same netgroup, and the size of `outbound_ipv46_peer_netgroups` would only be 1.
-            const bool count_failures{((int)outbound_ipv46_peer_netgroups.size() + outbound_privacy_network_peers) >= std::min(nMaxConnections - 1, 2)};
+            const bool count_failures{((int)outbound_ipv46_peer_netgroups.size() + outbound_privacy_network_peers) >= std::min(m_max_automatic_connections - 1, 2)};
             // Use BIP324 transport when both us and them have NODE_V2_P2P set.
             const bool use_v2transport(addrConnect.nServices & GetLocalServices() & NODE_P2P_V2);
             OpenNetworkConnection(addrConnect, count_failures, std::move(grant), /*strDest=*/nullptr, conn_type, use_v2transport);
@@ -4013,11 +4012,11 @@ bool CConnman::Start(CDeterministicMNManager& dmnman, CMasternodeMetaMan& mn_met
 
     if (semOutbound == nullptr) {
         // initialize semaphore
-        semOutbound = std::make_unique<CSemaphore>(std::min(m_max_outbound, nMaxConnections));
+        semOutbound = std::make_unique<CSemaphore>(std::min(m_max_automatic_outbound, m_max_automatic_connections));
     }
     if (semAddnode == nullptr) {
         // initialize semaphore
-        semAddnode = std::make_unique<CSemaphore>(nMaxAddnode);
+        semAddnode = std::make_unique<CSemaphore>(m_max_addnode);
     }
 
     //
@@ -4120,13 +4119,13 @@ void CConnman::Interrupt()
     InterruptSocks5(true);
 
     if (semOutbound) {
-        for (int i=0; i<m_max_outbound; i++) {
+        for (int i=0; i<m_max_automatic_outbound; i++) {
             semOutbound->post();
         }
     }
 
     if (semAddnode) {
-        for (int i=0; i<nMaxAddnode; i++) {
+        for (int i=0; i<m_max_addnode; i++) {
             semAddnode->post();
         }
     }
@@ -4486,7 +4485,7 @@ std::map<CNetAddr, LocalServiceInfo> CConnman::getNetLocalAddresses() const
 
 size_t CConnman::GetMaxOutboundNodeCount()
 {
-    return m_max_outbound;
+    return m_max_automatic_outbound;
 }
 
 size_t CConnman::GetMaxOutboundOnionNodeCount()

src/net.h

@@ -1185,12 +1185,8 @@ friend class CNode;
     struct Options
     {
         ServiceFlags nLocalServices = NODE_NONE;
-        int nMaxConnections = 0;
-        int m_max_outbound_full_relay = 0;
-        int m_max_outbound_block_relay = 0;
         int m_max_outbound_onion = 0;
-        int nMaxAddnode = 0;
-        int nMaxFeeler = 0;
+        int m_max_automatic_connections = 0;
         CClientUIInterface* uiInterface = nullptr;
         NetEventsInterface* m_msgproc = nullptr;
         BanMan* m_banman = nullptr;
@@ -1219,14 +1215,13 @@ friend class CNode;
         AssertLockNotHeld(m_total_bytes_sent_mutex);
 
         nLocalServices = connOptions.nLocalServices;
-        nMaxConnections = connOptions.nMaxConnections;
-        m_max_outbound_full_relay = std::min(connOptions.m_max_outbound_full_relay, connOptions.nMaxConnections);
-        m_max_outbound_block_relay = connOptions.m_max_outbound_block_relay;
+        m_max_automatic_connections = connOptions.m_max_automatic_connections;
+        m_max_outbound_full_relay = std::min(MAX_OUTBOUND_FULL_RELAY_CONNECTIONS, m_max_automatic_connections);
+        m_max_outbound_block_relay = std::min(MAX_BLOCK_RELAY_ONLY_CONNECTIONS, m_max_automatic_connections - m_max_outbound_full_relay);
+        m_max_automatic_outbound = m_max_outbound_full_relay + m_max_outbound_block_relay + m_max_feeler;
+        m_max_inbound = std::max(0, m_max_automatic_connections - m_max_automatic_outbound);
         m_max_outbound_onion = connOptions.m_max_outbound_onion;
         m_use_addrman_outgoing = connOptions.m_use_addrman_outgoing;
-        nMaxAddnode = connOptions.nMaxAddnode;
-        nMaxFeeler = connOptions.nMaxFeeler;
-        m_max_outbound = m_max_outbound_full_relay + m_max_outbound_block_relay + nMaxFeeler;
         m_client_interface = connOptions.uiInterface;
         m_banman = connOptions.m_banman;
         m_msgproc = connOptions.m_msgproc;
@@ -1829,7 +1824,18 @@ friend class CNode;
 
     std::unique_ptr<CSemaphore> semOutbound;
     std::unique_ptr<CSemaphore> semAddnode;
-    int nMaxConnections;
+
+    /**
+     * Maximum number of automatic connections permitted, excluding manual
+     * connections but including inbounds. May be changed by the user and is
+     * potentially limited by the operating system (number of file descriptors).
+     */
+    int m_max_automatic_connections;
+
+    /*
+     * Maximum number of peers by connection type. Might vary from defaults
+     * based on -maxconnections init value.
+     */
 
     // How many full-relay (tx, block, addr) outbound peers we want
     int m_max_outbound_full_relay;
@@ -1841,9 +1847,11 @@ friend class CNode;
     // How many onion outbound peers we want; don't care if full or block only; does not increase m_max_outbound
     int m_max_outbound_onion;
 
-    int nMaxAddnode;
-    int nMaxFeeler;
-    int m_max_outbound;
+    int m_max_addnode{MAX_ADDNODE_CONNECTIONS};
+    int m_max_feeler{MAX_FEELER_CONNECTIONS};
+    int m_max_automatic_outbound;
+    int m_max_inbound;
+
     bool m_use_addrman_outgoing;
     CClientUIInterface* m_client_interface;
     NetEventsInterface* m_msgproc;

src/rpc/util.cpp

@@ -18,6 +18,7 @@
 #include <util/system.h>
 #include <util/translation.h>
 
+#include <string_view>
 const std::string UNIX_EPOCH_TIME = "UNIX epoch time";
 const std::string EXAMPLE_ADDRESS[2] = {"XunLY9Tf7Zsef8gMGL2fhWA9ZmMjt4KPw0", "XwQQkwA4FYkq2XERzMY2CiAZhJTEDAbtc0"};
 
@@ -95,29 +96,29 @@ CAmount AmountFromValue(const UniValue& value, int decimals)
     return amount;
 }
 
-uint256 ParseHashV(const UniValue& v, std::string strName)
+uint256 ParseHashV(const UniValue& v, std::string_view name)
 {
     const std::string& strHex(v.get_str());
     if (64 != strHex.length())
-        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s must be of length %d (not %d, for '%s')", strName, 64, strHex.length(), strHex));
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s must be of length %d (not %d, for '%s')", name, 64, strHex.length(), strHex));
     if (!IsHex(strHex)) // Note: IsHex("") is false
-        throw JSONRPCError(RPC_INVALID_PARAMETER, strName+" must be hexadecimal string (not '"+strHex+"')");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s must be hexadecimal string (not '%s')", name, strHex));
     return uint256S(strHex);
 }
-uint256 ParseHashO(const UniValue& o, std::string strKey)
+uint256 ParseHashO(const UniValue& o, std::string_view strKey)
 {
     return ParseHashV(o.find_value(strKey), strKey);
 }
-std::vector<unsigned char> ParseHexV(const UniValue& v, std::string strName)
+std::vector<unsigned char> ParseHexV(const UniValue& v, std::string_view name)
 {
     std::string strHex;
     if (v.isStr())
         strHex = v.get_str();
     if (!IsHex(strHex))
-        throw JSONRPCError(RPC_INVALID_PARAMETER, strName+" must be hexadecimal string (not '"+strHex+"')");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s must be hexadecimal string (not '%s')", name, strHex));
     return ParseHex(strHex);
 }
-std::vector<unsigned char> ParseHexO(const UniValue& o, std::string strKey)
+std::vector<unsigned char> ParseHexO(const UniValue& o, std::string_view strKey)
 {
     return ParseHexV(o.find_value(strKey), strKey);
 }

src/rpc/util.h

@@ -19,6 +19,7 @@
 #include <util/strencodings.h>
 
 #include <string>
+#include <string_view>
 #include <variant>
 #include <vector>
 
@@ -88,10 +89,10 @@ void RPCTypeCheckObj(const UniValue& o,
  * Utilities: convert hex-encoded Values
  * (throws error if not hex).
  */
-uint256 ParseHashV(const UniValue& v, std::string strName);
-uint256 ParseHashO(const UniValue& o, std::string strKey);
-std::vector<unsigned char> ParseHexV(const UniValue& v, std::string strName);
-std::vector<unsigned char> ParseHexO(const UniValue& o, std::string strKey);
+uint256 ParseHashV(const UniValue& v, std::string_view name);
+uint256 ParseHashO(const UniValue& o, std::string_view strKey);
+std::vector<unsigned char> ParseHexV(const UniValue& v, std::string_view name);
+std::vector<unsigned char> ParseHexO(const UniValue& o, std::string_view strKey);
 
 bool ParseBoolV(const UniValue& v, const std::string &strName);
 

src/test/denialofservice_tests.cpp

@@ -150,9 +150,7 @@ BOOST_AUTO_TEST_CASE(stale_tip_peer_management)
 
     constexpr int max_outbound_full_relay = MAX_OUTBOUND_FULL_RELAY_CONNECTIONS;
     CConnman::Options options;
-    options.nMaxConnections = DEFAULT_MAX_PEER_CONNECTIONS;
-    options.m_max_outbound_full_relay = max_outbound_full_relay;
-    options.nMaxFeeler = MAX_FEELER_CONNECTIONS;
+    options.m_max_automatic_connections = DEFAULT_MAX_PEER_CONNECTIONS;
 
     const auto time_init{GetTime<std::chrono::seconds>()};
     SetMockTime(time_init);
@@ -252,9 +250,7 @@ BOOST_AUTO_TEST_CASE(block_relay_only_eviction)
     constexpr int max_outbound_block_relay{MAX_BLOCK_RELAY_ONLY_CONNECTIONS};
     constexpr int64_t MINIMUM_CONNECT_TIME{30};
     CConnman::Options options;
-    options.nMaxConnections = DEFAULT_MAX_PEER_CONNECTIONS;
-    options.m_max_outbound_full_relay = MAX_OUTBOUND_FULL_RELAY_CONNECTIONS;
-    options.m_max_outbound_block_relay = max_outbound_block_relay;
+    options.m_max_automatic_connections = DEFAULT_MAX_PEER_CONNECTIONS;
 
     connman->Init(options);
     std::vector<CNode*> vNodes;

src/util/strencodings.h

@@ -260,7 +260,6 @@ bool TimingResistantEqual(const T& a, const T& b)
 }
 
 /** Parse number as fixed point according to JSON number syntax.
- * See https://json.org/number.gif
  * @returns true on success, false on error.
  * @note The result must be in the range (-10^18,10^18), otherwise an overflow error will trigger.
  */