net: Add alternative port for onion service

This change allows to distinguish incoming Tor connections from others.

src/chainparamsbase.cpp

@@ -37,16 +37,20 @@ const CBaseChainParams& BaseParams()
     return *globalChainBaseParams;
 }
 
+/**
+ * Port numbers for incoming Tor connections (8334, 18334, 38334, 18445) have
+ * been chosen arbitrarily to keep ranges of used ports tight.
+ */
 std::unique_ptr<CBaseChainParams> CreateBaseChainParams(const std::string& chain)
 {
     if (chain == CBaseChainParams::MAIN) {
-        return MakeUnique<CBaseChainParams>("", 8332);
+        return MakeUnique<CBaseChainParams>("", 8332, 8334);
     } else if (chain == CBaseChainParams::TESTNET) {
-        return MakeUnique<CBaseChainParams>("testnet3", 18332);
+        return MakeUnique<CBaseChainParams>("testnet3", 18332, 18334);
     } else if (chain == CBaseChainParams::SIGNET) {
-        return MakeUnique<CBaseChainParams>("signet", 38332);
+        return MakeUnique<CBaseChainParams>("signet", 38332, 38334);
     } else if (chain == CBaseChainParams::REGTEST) {
-        return MakeUnique<CBaseChainParams>("regtest", 18443);
+        return MakeUnique<CBaseChainParams>("regtest", 18443, 18445);
     }
     throw std::runtime_error(strprintf("%s: Unknown chain %s.", __func__, chain));
 }

src/chainparamsbase.h

@@ -27,12 +27,15 @@ public:
 
     const std::string& DataDir() const { return strDataDir; }
     int RPCPort() const { return nRPCPort; }
+    uint16_t OnionServiceTargetPort() const { return m_onion_service_target_port; }
 
     CBaseChainParams() = delete;
-    CBaseChainParams(const std::string& data_dir, int rpc_port) : nRPCPort(rpc_port), strDataDir(data_dir) {}
+    CBaseChainParams(const std::string& data_dir, int rpc_port, uint16_t onion_service_target_port)
+        : nRPCPort(rpc_port), m_onion_service_target_port(onion_service_target_port), strDataDir(data_dir) {}
 
 private:
     int nRPCPort;
+    const uint16_t m_onion_service_target_port;
     std::string strDataDir;
 };