Allow disconnectnode() to be called with node id

disconnectnode() can currently only be called with the IP address/port
of the node the user wishes to connect. This commit allows the node to
be disconnected using the nodeid returned by getpeerinfo().

src/rpc/client.cpp

@@ -115,6 +115,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "bumpfee", 1, "options" },
     { "logging", 0, "include" },
     { "logging", 1, "exclude" },
+    { "disconnectnode", 1, "nodeid" },
     // Echo with conversion (For testing only)
     { "echojson", 0, "arg0" },
     { "echojson", 1, "arg1" },

src/rpc/net.cpp

@@ -234,23 +234,43 @@ UniValue addnode(const JSONRPCRequest& request)
 
 UniValue disconnectnode(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() != 1)
+    if (request.fHelp || request.params.size() == 0 || request.params.size() >= 3)
         throw std::runtime_error(
-            "disconnectnode \"address\" \n"
-            "\nImmediately disconnects from the specified node.\n"
+            "disconnectnode \"[address]\" [nodeid]\n"
+            "\nImmediately disconnects from the specified peer node.\n"
+            "\nStrictly one out of 'address' and 'nodeid' can be provided to identify the node.\n"
+            "\nTo disconnect by nodeid, either set 'address' to the empty string, or call using the named 'nodeid' argument only.\n"
             "\nArguments:\n"
-            "1. \"address\"     (string, required) The IP address/port of the node\n"
+            "1. \"address\"     (string, optional) The IP address/port of the node\n"
+            "2. \"nodeid\"      (number, optional) The node ID (see getpeerinfo for node IDs)\n"
             "\nExamples:\n"
             + HelpExampleCli("disconnectnode", "\"192.168.0.6:8333\"")
+            + HelpExampleCli("disconnectnode", "\"\" 1")
             + HelpExampleRpc("disconnectnode", "\"192.168.0.6:8333\"")
+            + HelpExampleRpc("disconnectnode", "\"\", 1")
         );
 
     if(!g_connman)
         throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
 
-    bool ret = g_connman->DisconnectNode(request.params[0].get_str());
-    if (!ret)
+    bool success;
+    const UniValue &address_arg = request.params[0];
+    const UniValue &id_arg = request.params.size() < 2 ? NullUniValue : request.params[1];
+
+    if (!address_arg.isNull() && id_arg.isNull()) {
+        /* handle disconnect-by-address */
+        success = g_connman->DisconnectNode(address_arg.get_str());
+    } else if (!id_arg.isNull() && (address_arg.isNull() || (address_arg.isStr() && address_arg.get_str().empty()))) {
+        /* handle disconnect-by-id */
+        NodeId nodeid = (NodeId) id_arg.get_int64();
+        success = g_connman->DisconnectNode(nodeid);
+    } else {
+        throw JSONRPCError(RPC_INVALID_PARAMS, "Only one of address and nodeid should be provided.");
+    }
+
+    if (!success) {
         throw JSONRPCError(RPC_CLIENT_NODE_NOT_CONNECTED, "Node not found in connected nodes");
+    }
 
     return NullUniValue;
 }
@@ -607,7 +627,7 @@ static const CRPCCommand commands[] =
     { "network",            "ping",                   &ping,                   true,  {} },
     { "network",            "getpeerinfo",            &getpeerinfo,            true,  {} },
     { "network",            "addnode",                &addnode,                true,  {"node","command"} },
-    { "network",            "disconnectnode",         &disconnectnode,         true,  {"address"} },
+    { "network",            "disconnectnode",         &disconnectnode,         true,  {"address", "nodeid"} },
     { "network",            "getaddednodeinfo",       &getaddednodeinfo,       true,  {"node"} },
     { "network",            "getnettotals",           &getnettotals,           true,  {} },
     { "network",            "getnetworkinfo",         &getnetworkinfo,         true,  {} },