Merge #19776: net, rpc: expose high bandwidth mode state via getpeerinfo

343dc47 test: add test for high-bandwidth mode states in getpeerinfo (Sebastian Falbesoner)
dab6583 doc: release note for new getpeerinfo fields "bip152_hb_{from,to}" (Sebastian Falbesoner)
a7ed00f rpc: expose high-bandwidth mode states via getpeerinfo (Sebastian Falbesoner)
30bc8fa net: save high-bandwidth mode states in CNodeStats (Sebastian Falbesoner)

Pull request description:

  Fixes #19676, "_For every peer expose through getpeerinfo RPC whether or not we selected them as HB peers, and whether or not they selected us as HB peers._" See [BIP152](https://github.com/bitcoin/bips/blob/master/bip-0152.mediawiki), in particular the [protocol flow diagram](https://github.com/bitcoin/bips/raw/master/bip-0152/protocol-flow.png).  The newly introduced states are changed on the following places in the code:
  * on reception of a `SENDCMPCT` message with valid version, the field `m_highbandwidth_from` is changed depending on the first integer parameter in the message (1=high bandwidth, 0=low bandwidth), i.e. it just mirrors the field `CNodeState.fPreferHeaderAndIDs`.
  * after adding a `SENDCMPCT` message to the send queue, the field `m_highbandwidth_to` is changed depending on how the first integer parameter is set (same as above)

  Note that after receiving `VERACK`, the node also sends `SENDCMPCT`, but that is only to announce the preferred version and never selects high-bandwidth mode, hence there is no need to change the state variables there, which are initialized to `false` anyways.

ACKs for top commit:
  naumenkogs:
    reACK 343dc47
  jonatack:
    re-ACK 343dc47 per `git range-diff 7ea6499 4df1d12 343dc47`

Tree-SHA512: f4999e6a935266812c2259a9b5dc459710037d3c9e938006d282557cc225e56128f72965faffb207fc60c6531fab1206db976dd8729a69e8ca29d4835317b99f

Author: MarcoFalke

doc/release-notes-19776.md

@@ -0,0 +1,9 @@
+Updated RPCs
+------------
+
+- The `getpeerinfo` RPC returns two new boolean fields, `bip152_hb_to` and
+  `bip152_hb_from`, that respectively indicate whether we selected a peer to be
+  in compact blocks high-bandwidth mode or whether a peer selected us as a
+  compact blocks high-bandwidth peer. High-bandwidth peers send new block
+  announcements via a `cmpctblock` message rather than the usual inv/headers
+  announcements. See BIP 152 for more details. (#19776)

src/net.cpp

@@ -584,6 +584,8 @@ void CNode::copyStats(CNodeStats &stats, const std::vector<bool> &m_asmap)
     }
     stats.fInbound = IsInboundConn();
     stats.m_manual_connection = IsManualConn();
+    X(m_bip152_highbandwidth_to);
+    X(m_bip152_highbandwidth_from);
     X(nStartingHeight);
     {
         LOCK(cs_vSend);

src/net.h

@@ -697,6 +697,8 @@ class CNodeStats
     std::string cleanSubVer;
     bool fInbound;
     bool m_manual_connection;
+    bool m_bip152_highbandwidth_to;
+    bool m_bip152_highbandwidth_from;
     int nStartingHeight;
     uint64_t nSendBytes;
     mapMsgCmdSize mapSendBytesPerMsgCmd;
@@ -984,6 +986,10 @@ class CNode
 public:
     uint256 hashContinue;
     std::atomic<int> nStartingHeight{-1};
+    // We selected peer as (compact blocks) high-bandwidth peer (BIP152)
+    std::atomic<bool> m_bip152_highbandwidth_to{false};
+    // Peer selected us as (compact blocks) high-bandwidth peer (BIP152)
+    std::atomic<bool> m_bip152_highbandwidth_from{false};
 
     // flood relay
     std::vector<CAddress> vAddrToSend;

src/net_processing.cpp

@@ -557,11 +557,15 @@ static void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid, CConnman& connma
                 // blocks using compact encodings.
                 connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(), [&connman, nCMPCTBLOCKVersion](CNode* pnodeStop){
                     connman.PushMessage(pnodeStop, CNetMsgMaker(pnodeStop->GetCommonVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/false, nCMPCTBLOCKVersion));
+                    // save BIP152 bandwidth state: we select peer to be low-bandwidth
+                    pnodeStop->m_bip152_highbandwidth_to = false;
                     return true;
                 });
                 lNodesAnnouncingHeaderAndIDs.pop_front();
             }
             connman.PushMessage(pfrom, CNetMsgMaker(pfrom->GetCommonVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/true, nCMPCTBLOCKVersion));
+            // save BIP152 bandwidth state: we select peer to be high-bandwidth
+            pfrom->m_bip152_highbandwidth_to = true;
             lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
             return true;
         });
@@ -2603,8 +2607,12 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
                 State(pfrom.GetId())->fProvidesHeaderAndIDs = true;
                 State(pfrom.GetId())->fWantsCmpctWitness = nCMPCTBLOCKVersion == 2;
             }
-            if (State(pfrom.GetId())->fWantsCmpctWitness == (nCMPCTBLOCKVersion == 2)) // ignore later version announces
+            if (State(pfrom.GetId())->fWantsCmpctWitness == (nCMPCTBLOCKVersion == 2)) { // ignore later version announces
                 State(pfrom.GetId())->fPreferHeaderAndIDs = fAnnounceUsingCMPCTBLOCK;
+                // save whether peer selects us as BIP152 high-bandwidth peer
+                // (receiving sendcmpct(1) signals high-bandwidth, sendcmpct(0) low-bandwidth)
+                pfrom.m_bip152_highbandwidth_from = fAnnounceUsingCMPCTBLOCK;
+            }
             if (!State(pfrom.GetId())->fSupportsDesiredCmpctVersion) {
                 if (pfrom.GetLocalServices() & NODE_WITNESS)
                     State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 2);

src/rpc/net.cpp

@@ -126,6 +126,8 @@ static RPCHelpMan getpeerinfo()
                             {RPCResult::Type::NUM, "version", "The peer version, such as 70001"},
                             {RPCResult::Type::STR, "subver", "The string version"},
                             {RPCResult::Type::BOOL, "inbound", "Inbound (true) or Outbound (false)"},
+                            {RPCResult::Type::BOOL, "bip152_hb_to", "Whether we selected peer as (compact blocks) high-bandwidth peer"},
+                            {RPCResult::Type::BOOL, "bip152_hb_from", "Whether peer selected us as (compact blocks) high-bandwidth peer"},
                             {RPCResult::Type::BOOL, "addnode", "Whether connection was due to addnode/-connect or if it was an automatic/inbound connection\n"
                                                                "(DEPRECATED, returned only if the config option -deprecatedrpc=getpeerinfo_addnode is passed)"},
                             {RPCResult::Type::STR, "connection_type", "Type of connection: \n" + Join(CONNECTION_TYPE_DOC, ",\n") + ".\n"
@@ -216,6 +218,8 @@ static RPCHelpMan getpeerinfo()
         // their ver message.
         obj.pushKV("subver", stats.cleanSubVer);
         obj.pushKV("inbound", stats.fInbound);
+        obj.pushKV("bip152_hb_to", stats.m_bip152_highbandwidth_to);
+        obj.pushKV("bip152_hb_from", stats.m_bip152_highbandwidth_from);
         if (IsDeprecatedRPCEnabled("getpeerinfo_addnode")) {
             // addnode is deprecated in v0.21 for removal in v0.22
             obj.pushKV("addnode", stats.m_manual_connection);

test/functional/p2p_compactblocks.py

@@ -764,6 +764,34 @@ def announce_cmpct_block(node, peer):
         stalling_peer.send_and_ping(msg)
         assert_equal(int(node.getbestblockhash(), 16), block.sha256)
 
+    def test_highbandwidth_mode_states_via_getpeerinfo(self):
+        # create new p2p connection for a fresh state w/o any prior sendcmpct messages sent
+        hb_test_node = self.nodes[0].add_p2p_connection(TestP2PConn(cmpct_version=2))
+
+        # assert the RPC getpeerinfo boolean fields `bip152_hb_{to, from}`
+        # match the given parameters for the last peer of a given node
+        def assert_highbandwidth_states(node, hb_to, hb_from):
+            peerinfo = node.getpeerinfo()[-1]
+            assert_equal(peerinfo['bip152_hb_to'], hb_to)
+            assert_equal(peerinfo['bip152_hb_from'], hb_from)
+
+        # initially, neither node has selected the other peer as high-bandwidth yet
+        assert_highbandwidth_states(self.nodes[0], hb_to=False, hb_from=False)
+
+        # peer requests high-bandwidth mode by sending sendcmpct(1)
+        hb_test_node.send_and_ping(msg_sendcmpct(announce=True, version=2))
+        assert_highbandwidth_states(self.nodes[0], hb_to=False, hb_from=True)
+
+        # peer generates a block and sends it to node, which should
+        # select the peer as high-bandwidth (up to 3 peers according to BIP 152)
+        block = self.build_block_on_tip(self.nodes[0])
+        hb_test_node.send_and_ping(msg_block(block))
+        assert_highbandwidth_states(self.nodes[0], hb_to=True, hb_from=True)
+
+        # peer requests low-bandwidth mode by sending sendcmpct(0)
+        hb_test_node.send_and_ping(msg_sendcmpct(announce=False, version=2))
+        assert_highbandwidth_states(self.nodes[0], hb_to=True, hb_from=False)
+
     def run_test(self):
         # Get the nodes out of IBD
         self.nodes[0].generate(1)
@@ -822,6 +850,9 @@ def run_test(self):
         self.log.info("Testing invalid index in cmpctblock message...")
         self.test_invalid_cmpctblock_message()
 
+        self.log.info("Testing high-bandwidth mode states via getpeerinfo...")
+        self.test_highbandwidth_mode_states_via_getpeerinfo()
+
 
 if __name__ == '__main__':
     CompactBlocksTest().main()