net, init: derive default onion port if a user specified a -port

After port collisions are no longer tolerated but lead to
a startup failure in v28.0, local setups of multiple nodes,
each with a different -port value would not be possible anymore
due to collision of the onion default port - even if the nodes
were using tor or not interested in receiving onion inbound connections.

Fix this by deriving the onion listening port to be -port + 1.
(idea by vasild / laanwj)

Co-authored-by: Vasil Dimov <vd@FreeBSD.org>

src/chainparamsbase.cpp

@@ -41,15 +41,15 @@ std::unique_ptr<CBaseChainParams> CreateBaseChainParams(const ChainType chain)
 {
     switch (chain) {
     case ChainType::MAIN:
-        return std::make_unique<CBaseChainParams>("", 8332, 8334);
+        return std::make_unique<CBaseChainParams>("", 8332);
     case ChainType::TESTNET:
-        return std::make_unique<CBaseChainParams>("testnet3", 18332, 18334);
+        return std::make_unique<CBaseChainParams>("testnet3", 18332);
     case ChainType::TESTNET4:
-        return std::make_unique<CBaseChainParams>("testnet4", 48332, 48334);
+        return std::make_unique<CBaseChainParams>("testnet4", 48332);
     case ChainType::SIGNET:
-        return std::make_unique<CBaseChainParams>("signet", 38332, 38334);
+        return std::make_unique<CBaseChainParams>("signet", 38332);
     case ChainType::REGTEST:
-        return std::make_unique<CBaseChainParams>("regtest", 18443, 18445);
+        return std::make_unique<CBaseChainParams>("regtest", 18443);
     }
     assert(false);
 }

src/chainparamsbase.h

@@ -22,15 +22,13 @@ class CBaseChainParams
 public:
     const std::string& DataDir() const { return strDataDir; }
     uint16_t RPCPort() const { return m_rpc_port; }
-    uint16_t OnionServiceTargetPort() const { return m_onion_service_target_port; }
 
     CBaseChainParams() = delete;
-    CBaseChainParams(const std::string& data_dir, uint16_t rpc_port, uint16_t onion_service_target_port)
-        : m_rpc_port(rpc_port), m_onion_service_target_port(onion_service_target_port), strDataDir(data_dir) {}
+    CBaseChainParams(const std::string& data_dir, uint16_t rpc_port)
+        : m_rpc_port(rpc_port), strDataDir(data_dir) {}
 
 private:
     const uint16_t m_rpc_port;
-    const uint16_t m_onion_service_target_port;
     std::string strDataDir;
 };
 

src/init.cpp

@@ -521,7 +521,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
     argsman.AddArg("-addnode=<ip>", strprintf("Add a node to connect to and attempt to keep the connection open (see the addnode RPC help for more info). This option can be specified multiple times to add multiple nodes; connections are limited to %u at a time and are counted separately from the -maxconnections limit.", MAX_ADDNODE_CONNECTIONS), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-asmap=<file>", strprintf("Specify asn mapping used for bucketing of the peers (default: %s). Relative paths will be prefixed by the net-specific datadir location.", DEFAULT_ASMAP_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-bantime=<n>", strprintf("Default duration (in seconds) of manually configured bans (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    argsman.AddArg("-bind=<addr>[:<port>][=onion]", strprintf("Bind to given address and always listen on it (default: 0.0.0.0). Use [host]:port notation for IPv6. Append =onion to tag any incoming connections to that address and port as incoming Tor connections (default: 127.0.0.1:%u=onion, testnet3: 127.0.0.1:%u=onion, testnet4: 127.0.0.1:%u=onion, signet: 127.0.0.1:%u=onion, regtest: 127.0.0.1:%u=onion)", defaultBaseParams->OnionServiceTargetPort(), testnetBaseParams->OnionServiceTargetPort(), testnet4BaseParams->OnionServiceTargetPort(), signetBaseParams->OnionServiceTargetPort(), regtestBaseParams->OnionServiceTargetPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-bind=<addr>[:<port>][=onion]", strprintf("Bind to given address and always listen on it (default: 0.0.0.0). Use [host]:port notation for IPv6. Append =onion to tag any incoming connections to that address and port as incoming Tor connections (default: 127.0.0.1:%u=onion, testnet3: 127.0.0.1:%u=onion, testnet4: 127.0.0.1:%u=onion, signet: 127.0.0.1:%u=onion, regtest: 127.0.0.1:%u=onion)", defaultChainParams->GetDefaultPort() + 1, testnetChainParams->GetDefaultPort() + 1, testnet4ChainParams->GetDefaultPort() + 1, signetChainParams->GetDefaultPort() + 1, regtestChainParams->GetDefaultPort() + 1), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-cjdnsreachable", "If set, then this host is configured for CJDNS (connecting to fc00::/8 addresses would lead us to the CJDNS network, see doc/cjdns.md) (default: 0)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-connect=<ip>", "Connect only to the specified node; -noconnect disables automatic connections (the rules for this peer are the same as for -addnode). This option can be specified multiple times to connect to multiple nodes.", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-discover", "Discover own IP addresses (default: 1 when listening and no -externalip or -proxy)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
@@ -548,7 +548,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
     argsman.AddArg("-peerbloomfilters", strprintf("Support filtering of blocks and transaction with bloom filters (default: %u)", DEFAULT_PEERBLOOMFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerblockfilters", strprintf("Serve compact block filters to peers per BIP 157 (default: %u)", DEFAULT_PEERBLOCKFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-txreconciliation", strprintf("Enable transaction reconciliations per BIP 330 (default: %d)", DEFAULT_TXRECONCILIATION_ENABLE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
-    argsman.AddArg("-port=<port>", strprintf("Listen for connections on <port> (default: %u, testnet3: %u, testnet4: %u, signet: %u, regtest: %u). Not relevant for I2P (see doc/i2p.md).", defaultChainParams->GetDefaultPort(), testnetChainParams->GetDefaultPort(), testnet4ChainParams->GetDefaultPort(), signetChainParams->GetDefaultPort(), regtestChainParams->GetDefaultPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-port=<port>", strprintf("Listen for connections on <port> (default: %u, testnet3: %u, testnet4: %u, signet: %u, regtest: %u). Not relevant for I2P (see doc/i2p.md). If set to a value x, the default onion listening port will be set to x+1.", defaultChainParams->GetDefaultPort(), testnetChainParams->GetDefaultPort(), testnet4ChainParams->GetDefaultPort(), signetChainParams->GetDefaultPort(), regtestChainParams->GetDefaultPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
 #ifdef HAVE_SOCKADDR_UN
     argsman.AddArg("-proxy=<ip:port|path>", "Connect through SOCKS5 proxy, set -noproxy to disable (default: disabled). May be a local file path prefixed with 'unix:' if the proxy supports it.", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_ELISION, OptionsCategory::CONNECTION);
 #else
@@ -1846,6 +1846,8 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     const uint16_t default_bind_port =
         static_cast<uint16_t>(args.GetIntArg("-port", Params().GetDefaultPort()));
 
+    const uint16_t default_bind_port_onion = default_bind_port + 1;
+
     const auto BadPortWarning = [](const char* prefix, uint16_t port) {
         return strprintf(_("%s request to listen on port %u. This port is considered \"bad\" and "
                            "thus it is unlikely that any peer will connect to it. See "
@@ -1870,7 +1872,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
             const std::string network_type = bind_arg.substr(index + 1);
             if (network_type == "onion") {
                 const std::string truncated_bind_arg = bind_arg.substr(0, index);
-                bind_addr = Lookup(truncated_bind_arg, BaseParams().OnionServiceTargetPort(), false);
+                bind_addr = Lookup(truncated_bind_arg, default_bind_port_onion, false);
                 if (bind_addr.has_value()) {
                     connOptions.onion_binds.push_back(bind_addr.value());
                     continue;
@@ -1906,7 +1908,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     } else if (!connOptions.vBinds.empty()) {
         onion_service_target = connOptions.vBinds.front();
     } else {
-        onion_service_target = DefaultOnionServiceTarget();
+        onion_service_target = DefaultOnionServiceTarget(default_bind_port_onion);
         connOptions.onion_binds.push_back(onion_service_target);
     }
 

src/torcontrol.cpp

@@ -711,9 +711,9 @@ void StopTorControl()
     }
 }
 
-CService DefaultOnionServiceTarget()
+CService DefaultOnionServiceTarget(uint16_t port)
 {
     struct in_addr onion_service_target;
     onion_service_target.s_addr = htonl(INADDR_LOOPBACK);
-    return {onion_service_target, BaseParams().OnionServiceTargetPort()};
+    return {onion_service_target, port};
 }

src/torcontrol.h

@@ -27,7 +27,7 @@ void StartTorControl(CService onion_service_target);
 void InterruptTorControl();
 void StopTorControl();
 
-CService DefaultOnionServiceTarget();
+CService DefaultOnionServiceTarget(uint16_t port);
 
 /** Reply from Tor, can be single or multi-line */
 class TorControlReply

test/functional/test_framework/test_node.py

@@ -221,10 +221,9 @@ class TestNode():
             extra_args = self.extra_args
 
         # If listening and no -bind is given, then bitcoind would bind P2P ports on
-        # 0.0.0.0:P and 127.0.0.1:18445 (for incoming Tor connections), where P is
+        # 0.0.0.0:P and 127.0.0.1:P+1 (for incoming Tor connections), where P is
         # a unique port chosen by the test framework and configured as port=P in
-        # bitcoin.conf. To avoid collisions on 127.0.0.1:18445, change it to
-        # 127.0.0.1:tor_port().
+        # bitcoin.conf. To avoid collisions, change it to 127.0.0.1:tor_port().
         will_listen = all(e != "-nolisten" and e != "-listen=0" for e in extra_args)
         has_explicit_bind = self.has_explicit_bind or any(e.startswith("-bind=") for e in extra_args)
         if will_listen and not has_explicit_bind: