ci/4

src/CMakeLists.txt

@@ -244,6 +244,7 @@ add_library(bitcoin_node STATIC EXCLUDE_FROM_ALL
   policy/rbf.cpp
   policy/settings.cpp
   policy/truc_policy.cpp
+  private_broadcast.cpp
   rest.cpp
   rpc/blockchain.cpp
   rpc/external_signer.cpp

src/bitcoin-cli.cpp

@@ -452,6 +452,7 @@ class NetinfoRequestHandler : public BaseRequestHandler
         if (conn_type == "block-relay-only") return "block";
         if (conn_type == "manual" || conn_type == "feeler") return conn_type;
         if (conn_type == "addr-fetch") return "addr";
+        if (conn_type == "private-broadcast") return "priv";
         return "";
     }
     std::string FormatServices(const UniValue& services)
@@ -703,6 +704,7 @@ class NetinfoRequestHandler : public BaseRequestHandler
         "           \"manual\" - peer we manually added using RPC addnode or the -addnode/-connect config options\n"
         "           \"feeler\" - short-lived connection for testing addresses\n"
         "           \"addr\"   - address fetch; short-lived connection for requesting addresses\n"
+        "           \"priv\"   - private broadcast; short-lived connection for broadcasting our transactions\n"
         "  net      Network the peer connected through (\"ipv4\", \"ipv6\", \"onion\", \"i2p\", \"cjdns\", or \"npr\" (not publicly routable))\n"
         "  serv     Services offered by the peer\n"
         "           \"n\" - NETWORK: peer can serve the full block chain\n"

src/init.cpp

@@ -543,7 +543,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
     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> automatic connections to peers (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 (default: %u). This limit does not apply to connections manually added via -addnode or the addnode RPC, which have a separate limit of %u. It does not apply to short-lived private broadcast connections either, which have a separate limit of %u.", DEFAULT_MAX_PEER_CONNECTIONS, MAX_ADDNODE_CONNECTIONS, MAX_PRIVATE_BROADCAST_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("-maxuploadtarget=<n>", strprintf("Tries to keep outbound traffic under the given target per 24h. Limit does not apply to peers with 'download' permission or blocks created within past week. 0 = no limit (default: %s). Optional suffix units [k|K|m|M|g|G|t|T] (default: M). Lowercase is 1000 base while uppercase is 1024 base", DEFAULT_MAX_UPLOAD_TARGET), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
@@ -666,6 +666,15 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
                    OptionsCategory::NODE_RELAY);
     argsman.AddArg("-minrelaytxfee=<amt>", strprintf("Fees (in %s/kvB) smaller than this are considered zero fee for relaying, mining and transaction creation (default: %s)",
         CURRENCY_UNIT, FormatMoney(DEFAULT_MIN_RELAY_TX_FEE)), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
+    argsman.AddArg("-privatebroadcast",
+                   strprintf(
+                       "Broadcast transactions submitted via sendrawtransaction RPC using short-lived "
+                       "connections through the Tor or I2P networks, without putting them in the mempool first. "
+                       "Transactions submitted through the wallet are not affected by this option "
+                       "(default: %u)",
+                   DEFAULT_PRIVATE_BROADCAST),
+                   ArgsManager::ALLOW_ANY,
+                   OptionsCategory::NODE_RELAY);
     argsman.AddArg("-whitelistforcerelay", strprintf("Add 'forcerelay' permission to whitelisted peers with default permissions. This will relay transactions even if the transactions were already in the mempool. (default: %d)", DEFAULT_WHITELISTFORCERELAY), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg("-whitelistrelay", strprintf("Add 'relay' permission to whitelisted peers with default permissions. This will accept relayed transactions even when not relaying transactions (default: %d)", DEFAULT_WHITELISTRELAY), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
 
@@ -999,11 +1008,14 @@ bool AppInitParameterInteraction(const ArgsManager& args)
     if (user_max_connection < 0) {
         return InitError(Untranslated("-maxconnections must be greater or equal than zero"));
     }
+    const size_t max_private{args.GetBoolArg("-privatebroadcast", DEFAULT_PRIVATE_BROADCAST)
+                             ? MAX_PRIVATE_BROADCAST_CONNECTIONS
+                             : 0};
     // Reserve enough FDs to account for the bare minimum, plus any manual connections, plus the bound interfaces
     int min_required_fds = MIN_CORE_FDS + MAX_ADDNODE_CONNECTIONS + nBind;
 
     // Try raising the FD limit to what we need (available_fds may be smaller than the requested amount if this fails)
-    available_fds = RaiseFileDescriptorLimit(user_max_connection + min_required_fds);
+    available_fds = RaiseFileDescriptorLimit(user_max_connection + max_private + min_required_fds);
     // If we are using select instead of poll, our actual limit may be even smaller
 #ifndef USE_POLL
     available_fds = std::min(FD_SETSIZE, available_fds);
@@ -1718,13 +1730,13 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         }
     }
 
+    const bool listenonion{args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)};
     if (onion_proxy.IsValid()) {
         SetProxy(NET_ONION, onion_proxy);
     } else {
         // If -listenonion is set, then we will (try to) connect to the Tor control port
         // later from the torcontrol thread and may retrieve the onion proxy from there.
-        const bool listenonion_disabled{!args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)};
-        if (onlynet_used_with_onion && listenonion_disabled) {
+        if (onlynet_used_with_onion && !listenonion) {
             return InitError(
                 _("Outbound connections restricted to Tor (-onlynet=onion) but the proxy for "
                   "reaching the Tor network is not provided: none of -proxy, -onion or "
@@ -2100,7 +2112,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         connOptions.onion_binds.push_back(onion_service_target);
     }
 
-    if (args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)) {
+    if (listenonion) {
         if (connOptions.onion_binds.size() > 1) {
             InitWarning(strprintf(_("More than one onion bind address is provided. Using %s "
                                     "for the automatically created Tor onion service."),
@@ -2173,6 +2185,32 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                     conflict->ToStringAddrPort()));
     }
 
+    if (args.GetBoolArg("-privatebroadcast", DEFAULT_PRIVATE_BROADCAST)) {
+        // If -listenonion is set, then NET_ONION may not be reachable now
+        // but may become reachable later, thus only error here if it is not
+        // reachable and will not become reachable for sure.
+        const bool onion_may_become_reachable{listenonion && (!args.IsArgSet("-onlynet") || onlynet_used_with_onion)};
+        if (!g_reachable_nets.Contains(NET_I2P) &&
+            !g_reachable_nets.Contains(NET_ONION) &&
+            !onion_may_become_reachable) {
+            return InitError(_("Private broadcast of own transactions requested (-privatebroadcast), "
+                               "but none of Tor or I2P networks is reachable"));
+        }
+        if (!connOptions.m_use_addrman_outgoing) {
+            return InitError(_("Private broadcast of own transactions requested (-privatebroadcast), "
+                               "but -connect is also configured. They are incompatible because the "
+                               "private broadcast needs to open new connections to randomly "
+                               "chosen Tor or I2P peers. Consider using -maxconnections=0 -addnode=... "
+                               "instead"));
+        }
+        if (!proxyRandomize && (g_reachable_nets.Contains(NET_ONION) || onion_may_become_reachable)) {
+            InitWarning(_("Private broadcast of own transactions requested (-privatebroadcast) and "
+                          "-proxyrandomize is disabled. Tor circuits for private broadcast connections "
+                          "may be correlated to other connections over Tor. For maximum privacy set "
+                          "-proxyrandomize=1."));
+        }
+    }
+
     if (!node.connman->Start(scheduler, connOptions)) {
         return false;
     }

src/logging.cpp

@@ -202,6 +202,7 @@ static const std::map<std::string, BCLog::LogFlags, std::less<>> LOG_CATEGORIES_
     {"scan", BCLog::SCAN},
     {"txpackages", BCLog::TXPACKAGES},
     {"kernel", BCLog::KERNEL},
+    {"privatebroadcast", BCLog::PRIVATE_BROADCAST},
 };
 
 static const std::unordered_map<BCLog::LogFlags, std::string> LOG_CATEGORIES_BY_FLAG{

src/logging.h

@@ -95,6 +95,7 @@ namespace BCLog {
         SCAN        = (CategoryMask{1} << 27),
         TXPACKAGES  = (CategoryMask{1} << 28),
         KERNEL      = (CategoryMask{1} << 29),
+        PRIVATE_BROADCAST = (CategoryMask{1} << 30),
         ALL         = ~NONE,
     };
     enum class Level {