More agressively filter compact block requests

Unit test adaptations by Pieter Wuille.

qa/rpc-tests/p2p-compactblocks.py

@@ -591,7 +591,7 @@ class CompactBlocksTest(BitcoinTestFramework):
     def test_getblocktxn_handler(self, node, test_node, version):
         # bitcoind won't respond for blocks whose height is more than 15 blocks
         # deep.
-        MAX_GETBLOCKTXN_DEPTH = 15
+        MAX_GETBLOCKTXN_DEPTH = 10
         chain_height = node.getblockcount()
         current_height = chain_height
         while (current_height >= chain_height - MAX_GETBLOCKTXN_DEPTH):
@@ -632,7 +632,7 @@ class CompactBlocksTest(BitcoinTestFramework):
 
     def test_compactblocks_not_at_tip(self, node, test_node):
         # Test that requesting old compactblocks doesn't work.
-        MAX_CMPCTBLOCK_DEPTH = 11
+        MAX_CMPCTBLOCK_DEPTH = 6
         new_blocks = []
         for i in range(MAX_CMPCTBLOCK_DEPTH):
             test_node.clear_block_announcement()

src/main.cpp

@@ -4878,7 +4878,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                         // and we don't feel like constructing the object for them, so
                         // instead we respond with the full, non-compact block.
                         bool fPeerWantsWitness = State(pfrom->GetId())->fWantsCmpctWitness;
-                        if (mi->second->nHeight >= chainActive.Height() - 10) {
+                        if (CanDirectFetch(Params().GetConsensus()) && mi->second->nHeight >= chainActive.Height() - 5) {
                             CBlockHeaderAndShortTxIDs cmpctblock(block, fPeerWantsWitness);
                             pfrom->PushMessageWithFlag(fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::CMPCTBLOCK, cmpctblock);
                         } else
@@ -5405,8 +5405,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             return true;
         }
 
-        if (it->second->nHeight < chainActive.Height() - 15) {
-            LogPrint("net", "Peer %d sent us a getblocktxn for a block > 15 deep", pfrom->id);
+        if (it->second->nHeight < chainActive.Height() - 10) {
+            LogPrint("net", "Peer %d sent us a getblocktxn for a block > 10 deep", pfrom->id);
             return true;
         }