Disconnect peers violating blocks-only mode

If we set fRelay=false in our VERSION message, and a peer sends an INV or TX
message anyway, disconnect. Since we use fRelay=false to minimize bandwidth,
we should not tolerate remaining connected to a peer violating the protocol.

Author: sdaftuar

src/net_processing.cpp

@@ -2266,7 +2266,9 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
             {
                 pfrom->AddInventoryKnown(inv);
                 if (fBlocksOnly) {
-                    LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol peer=%d\n", inv.hash.ToString(), pfrom->GetId());
+                    LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol, disconnecting peer=%d\n", inv.hash.ToString(), pfrom->GetId());
+                    pfrom->fDisconnect = true;
+                    return true;
                 } else if (!fAlreadyHave && !fImporting && !fReindex && !::ChainstateActive().IsInitialBlockDownload()) {
                     RequestTx(State(pfrom->GetId()), inv.hash, current_time);
                 }
@@ -2483,9 +2485,11 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
     if (strCommand == NetMsgType::TX) {
         // Stop processing the transaction early if
         // We are in blocks only mode and peer is either not whitelisted or whitelistrelay is off
-        if (!g_relay_txes && !pfrom->HasPermission(PF_RELAY))
+        // or if this peer is supposed to be a block-relay-only peer
+        if ((!g_relay_txes && !pfrom->HasPermission(PF_RELAY)) || (pfrom->m_tx_relay == nullptr))
         {
             LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom->GetId());
+            pfrom->fDisconnect = true;
             return true;
         }
 

test/functional/p2p_blocksonly.py

@@ -19,7 +19,7 @@ def set_test_params(self):
     def run_test(self):
         self.nodes[0].add_p2p_connection(P2PInterface())
 
-        self.log.info('Check that txs from p2p are rejected')
+        self.log.info('Check that txs from p2p are rejected and result in disconnect')
         prevtx = self.nodes[0].getblock(self.nodes[0].getblockhash(1), 2)['tx'][0]
         rawtx = self.nodes[0].createrawtransaction(
             inputs=[{
@@ -42,13 +42,17 @@ def run_test(self):
         assert_equal(self.nodes[0].getnetworkinfo()['localrelay'], False)
         with self.nodes[0].assert_debug_log(['transaction sent in violation of protocol peer=0']):
             self.nodes[0].p2p.send_message(msg_tx(FromHex(CTransaction(), sigtx)))
-            self.nodes[0].p2p.sync_with_ping()
+            self.nodes[0].p2p.wait_for_disconnect()
             assert_equal(self.nodes[0].getmempoolinfo()['size'], 0)
 
+        # Remove the disconnected peer and add a new one.
+        del self.nodes[0].p2ps[0]
+        self.nodes[0].add_p2p_connection(P2PInterface())
+
         self.log.info('Check that txs from rpc are not rejected and relayed to other peers')
         assert_equal(self.nodes[0].getpeerinfo()[0]['relaytxes'], True)
         txid = self.nodes[0].testmempoolaccept([sigtx])[0]['txid']
-        with self.nodes[0].assert_debug_log(['received getdata for: tx {} peer=0'.format(txid)]):
+        with self.nodes[0].assert_debug_log(['received getdata for: tx {} peer=1'.format(txid)]):
             self.nodes[0].sendrawtransaction(sigtx)
             self.nodes[0].p2p.wait_for_tx(txid)
             assert_equal(self.nodes[0].getmempoolinfo()['size'], 1)