Merge bitcoin/bitcoin#21327: net_processing: ignore transactions while in IBD

6aed8b7e9b [test] tx processing before and after ibd (glozow)
b9e105b664 [net_processing] ignore all transactions during ibd (glozow)

Pull request description:

  This is basically a mini, IBD-only version of #21224

  Incoming transactions aren't really relevant until we're caught up. That's why we send a giant feefilter and don't send tx getdatas, but we also shouldn't process them if peers send them anyway. Simply ignore them.

ACKs for top commit:
  jnewbery:
    reACK 6aed8b7e9b
  laanwj:
    Code review ACK 6aed8b7e9b

Tree-SHA512: 8e1616bf355f9d0b180bdbc5461f24c757dc5d7bc7bf651470f3b0bffcca5d5e68287106255b5cede2d96b42bce448a0f8c0649de35a530c5e079f7c89c70a35

src/net_processing.cpp

@@ -3206,6 +3206,11 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             return;
         }
 
+        // Stop processing the transaction early if we are still in IBD since we don't
+        // have enough information to validate it yet. Sending unsolicited transactions
+        // is not considered a protocol violation, so don't punish the peer.
+        if (m_chainman.ActiveChainstate().IsInitialBlockDownload()) return;
+
         CTransactionRef ptx;
         vRecv >> ptx;
         const CTransaction& tx = *ptx;

test/functional/p2p_ibd_txrelay.py

@@ -2,11 +2,30 @@
 # Copyright (c) 2020-2021 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
-"""Test fee filters during and after IBD."""
+"""Test transaction relay behavior during IBD:
+- Set fee filters to MAX_MONEY
+- Don't request transactions
+- Ignore all transaction messages
+"""
 
 from decimal import Decimal
+import time
 
-from test_framework.messages import COIN
+from test_framework.messages import (
+        CInv,
+        COIN,
+        CTransaction,
+        from_hex,
+        msg_inv,
+        msg_tx,
+        MSG_WTX,
+)
+from test_framework.p2p import (
+        NONPREF_PEER_TX_DELAY,
+        P2PDataStore,
+        P2PInterface,
+        p2p_lock
+)
 from test_framework.test_framework import BitcoinTestFramework
 
 MAX_FEE_FILTER = Decimal(9170997) / COIN
@@ -28,6 +47,31 @@ class P2PIBDTxRelayTest(BitcoinTestFramework):
             assert node.getblockchaininfo()['initialblockdownload']
             self.wait_until(lambda: all(peer['minfeefilter'] == MAX_FEE_FILTER for peer in node.getpeerinfo()))
 
+        self.log.info("Check that nodes don't send getdatas for transactions while still in IBD")
+        peer_inver = self.nodes[0].add_p2p_connection(P2PDataStore())
+        txid = 0xdeadbeef
+        peer_inver.send_and_ping(msg_inv([CInv(t=MSG_WTX, h=txid)]))
+        # The node should not send a getdata, but if it did, it would first delay 2 seconds
+        self.nodes[0].setmocktime(int(time.time() + NONPREF_PEER_TX_DELAY))
+        peer_inver.sync_send_with_ping()
+        with p2p_lock:
+            assert txid not in peer_inver.getdata_requests
+        self.nodes[0].disconnect_p2ps()
+
+        self.log.info("Check that nodes don't process unsolicited transactions while still in IBD")
+        # A transaction hex pulled from tx_valid.json. There are no valid transactions since no UTXOs
+        # exist yet, but it should be a well-formed transaction.
+        rawhex = "0100000001b14bdcbc3e01bdaad36cc08e81e69c82e1060bc14e518db2b49aa43ad90ba260000000004a01ff473" + \
+            "04402203f16c6f40162ab686621ef3000b04e75418a0c0cb2d8aebeac894ae360ac1e780220ddc15ecdfc3507ac48e168" + \
+            "1a33eb60996631bf6bf5bc0a0682c4db743ce7ca2b01ffffffff0140420f00000000001976a914660d4ef3a743e3e696a" + \
+            "d990364e555c271ad504b88ac00000000"
+        assert self.nodes[1].decoderawtransaction(rawhex) # returns a dict, should not throw
+        tx = from_hex(CTransaction(), rawhex)
+        peer_txer = self.nodes[0].add_p2p_connection(P2PInterface())
+        with self.nodes[0].assert_debug_log(expected_msgs=["received: tx"], unexpected_msgs=["was not accepted"]):
+            peer_txer.send_and_ping(msg_tx(tx))
+        self.nodes[0].disconnect_p2ps()
+
         # Come out of IBD by generating a block
         self.generate(self.nodes[0], 1)
 
@@ -36,6 +80,10 @@ class P2PIBDTxRelayTest(BitcoinTestFramework):
             assert not node.getblockchaininfo()['initialblockdownload']
             self.wait_until(lambda: all(peer['minfeefilter'] == NORMAL_FEE_FILTER for peer in node.getpeerinfo()))
 
+        self.log.info("Check that nodes process the same transaction, even when unsolicited, when no longer in IBD")
+        peer_txer = self.nodes[0].add_p2p_connection(P2PInterface())
+        with self.nodes[0].assert_debug_log(expected_msgs=["was not accepted"]):
+            peer_txer.send_and_ping(msg_tx(tx))
 
 if __name__ == '__main__':
     P2PIBDTxRelayTest().main()

test/functional/test_framework/p2p.py

@@ -89,6 +89,8 @@ P2P_SERVICES = NODE_NETWORK | NODE_WITNESS
 P2P_SUBVERSION = "/python-p2p-tester:0.0.3/"
 # Value for relay that this test framework sends in its `version` message
 P2P_VERSION_RELAY = 1
+# Delay after receiving a tx inv before requesting transactions from non-preferred peers, in seconds
+NONPREF_PEER_TX_DELAY = 2
 
 MESSAGEMAP = {
     b"addr": msg_addr,