Merge pull request #4468

e11b2ce Fix large reorgs (Pieter Wuille)
afc32c5 Fix rebuild-chainstate feature and improve its performance (Pieter Wuille)
16d5194 Skip reindexed blocks individually (Pieter Wuille)
ad96e7c Make -reindex cope with out-of-order blocks (Wladimir J. van der Laan)
e17bd58 Rename setBlockIndexValid to setBlockIndexCandidates (Pieter Wuille)
1af838b Add height to "Requesting block" debug (R E Broadley)
1bcee67 Better logging of stalling (R E Broadley)
4c93322 Improve getheaders (sending) logging (R E Broadley)
f244c99 Remove CheckMinWork, as we always know all parent headers (Pieter Wuille)
ad6e601 RPC additions after headers-first (Pieter Wuille)
341735e Headers-first synchronization (Pieter Wuille)

qa/pull-tester/run-bitcoind-for-test.sh.in

@@ -10,7 +10,7 @@ touch "$DATADIR/regtest/debug.log"
 tail -q -n 1 -F "$DATADIR/regtest/debug.log" | grep -m 1 -q "Done loading" &
 WAITER=$!
 PORT=`expr 10000 + $$ % 55536`
-"@abs_top_builddir@/src/bitcoind@EXEEXT@" -connect=0.0.0.0 -datadir="$DATADIR" -rpcuser=user -rpcpassword=pass -listen -keypool=3 -debug -debug=net -logtimestamps -port=$PORT -whitelist=127.0.0.1 -regtest -rpcport=`expr $PORT + 1` &
+"@abs_top_builddir@/src/bitcoind@EXEEXT@" -connect=0.0.0.0 -datadir="$DATADIR" -rpcuser=user -rpcpassword=pass -listen -keypool=3 -debug -debug=net -logtimestamps -checkmempool=0 -port=$PORT -whitelist=127.0.0.1 -regtest -rpcport=`expr $PORT + 1` &
 BITCOIND=$!
 
 #Install a watchdog.

src/chain.h

@@ -49,12 +49,29 @@ struct CDiskBlockPos
 };
 
 enum BlockStatus {
+    // Unused.
     BLOCK_VALID_UNKNOWN      =    0,
-    BLOCK_VALID_HEADER       =    1, // parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future
-    BLOCK_VALID_TREE         =    2, // parent found, difficulty matches, timestamp >= median previous, checkpoint
-    BLOCK_VALID_TRANSACTIONS =    3, // only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids, sigops, size, merkle root
-    BLOCK_VALID_CHAIN        =    4, // outputs do not overspend inputs, no double spends, coinbase output ok, immature coinbase spends, BIP30
-    BLOCK_VALID_SCRIPTS      =    5, // scripts/signatures ok
+
+    // Parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future
+    BLOCK_VALID_HEADER       =    1,
+
+    // All parent headers found, difficulty matches, timestamp >= median previous, checkpoint. Implies all parents
+    // are also at least TREE.
+    BLOCK_VALID_TREE         =    2,
+
+    // Only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids,
+    // sigops, size, merkle root. Implies all parents are at least TREE but not necessarily TRANSACTIONS. When all
+    // parent blocks also have TRANSACTIONS, CBlockIndex::nChainTx will be set.
+    BLOCK_VALID_TRANSACTIONS =    3,
+
+    // Outputs do not overspend inputs, no double spends, coinbase output ok, immature coinbase spends, BIP30.
+    // Implies all parents are also at least CHAIN.
+    BLOCK_VALID_CHAIN        =    4,
+
+    // Scripts & signatures ok. Implies all parents are also at least SCRIPTS.
+    BLOCK_VALID_SCRIPTS      =    5,
+
+    // All validity bits.
     BLOCK_VALID_MASK         =   BLOCK_VALID_HEADER | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS |
                                  BLOCK_VALID_CHAIN | BLOCK_VALID_SCRIPTS,
 
@@ -103,7 +120,8 @@ public:
     // Note: in a potential headers-first mode, this number cannot be relied upon
     unsigned int nTx;
 
-    // (memory only) Number of transactions in the chain up to and including this block
+    // (memory only) Number of transactions in the chain up to and including this block.
+    // This value will be non-zero only if and only if transactions for this block and all its parents are available.
     unsigned int nChainTx; // change to 64-bit type when necessary; won't happen before 2030
 
     // Verification status of this block. See enum BlockStatus
@@ -146,7 +164,7 @@ public:
         SetNull();
     }
 
-    CBlockIndex(CBlockHeader& block)
+    CBlockIndex(const CBlockHeader& block)
     {
         SetNull();
 

src/init.cpp

@@ -974,7 +974,7 @@ bool AppInit2(boost::thread_group& threadGroup)
 
                 // If the loaded chain has a wrong genesis, bail out immediately
                 // (we're likely using a testnet datadir, or the other way around).
-                if (!mapBlockIndex.empty() && chainActive.Genesis() == NULL)
+                if (!mapBlockIndex.empty() && mapBlockIndex.count(Params().HashGenesisBlock()) == 0)
                     return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));
 
                 // Initialize the block index (no-op if non-empty database was already loaded)

src/main.h

@@ -72,9 +72,17 @@ static const int MAX_SCRIPTCHECK_THREADS = 16;
 /** -par default (number of script-checking threads, 0 = auto) */
 static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
 /** Number of blocks that can be requested at any given time from a single peer. */
-static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 128;
-/** Timeout in seconds before considering a block download peer unresponsive. */
-static const unsigned int BLOCK_DOWNLOAD_TIMEOUT = 60;
+static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
+/** Timeout in seconds during which a peer must stall block download progress before being disconnected. */
+static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
+/** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
+ *  less than this number, we reached their tip. Changing this value is a protocol upgrade. */
+static const unsigned int MAX_HEADERS_RESULTS = 2000;
+/** Size of the "block download window": how far ahead of our current height do we fetch?
+ *  Larger windows tolerate larger download speed differences between peer, but increase the potential
+ *  degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
+ *  harder). We'll probably want to make this a per-peer adaptive value at some point. */
+static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
 
 /** "reject" message codes **/
 static const unsigned char REJECT_MALFORMED = 0x01;
@@ -110,6 +118,9 @@ extern bool fIsBareMultisigStd;
 extern unsigned int nCoinCacheSize;
 extern CFeeRate minRelayTxFee;
 
+// Best header we've seen so far (used for getheaders queries' starting points).
+extern CBlockIndex *pindexBestHeader;
+
 // Minimum disk space required - used in CheckDiskSpace()
 static const uint64_t nMinDiskSpace = 52428800;
 
@@ -137,8 +148,6 @@ void RegisterNodeSignals(CNodeSignals& nodeSignals);
 /** Unregister a network node */
 void UnregisterNodeSignals(CNodeSignals& nodeSignals);
 
-void PushGetBlocks(CNode* pnode, CBlockIndex* pindexBegin, uint256 hashEnd);
-
 /** Process an incoming block */
 bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBlockPos *dbp = NULL);
 /** Check whether enough disk space is available for an incoming block */
@@ -193,6 +202,8 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
 struct CNodeStateStats {
     int nMisbehavior;
     int nSyncHeight;
+    int nCommonHeight;
+    std::vector<int> vHeightInFlight;
 };
 
 struct CDiskTxPos : public CDiskBlockPos
@@ -439,9 +450,6 @@ bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex
 // Apply the effects of this block (with given index) on the UTXO set represented by coins
 bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& coins, bool fJustCheck = false);
 
-// Add this block to the block index, and if necessary, switch the active block chain to this
-bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos& pos);
-
 // Context-independent validity checks
 bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW = true);
 bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
@@ -449,7 +457,7 @@ bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW = t
 // Store block on disk
 // if dbp is provided, the file is known to already reside on disk
 bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex **pindex, CDiskBlockPos* dbp = NULL);
-bool AcceptBlockHeader(CBlockHeader& block, CValidationState& state, CBlockIndex **ppindex= NULL);
+bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex **ppindex= NULL);
 
 
 

src/net.cpp

@@ -73,7 +73,6 @@ map<CNetAddr, LocalServiceInfo> mapLocalHost;
 static bool vfReachable[NET_MAX] = {};
 static bool vfLimited[NET_MAX] = {};
 static CNode* pnodeLocalHost = NULL;
-static CNode* pnodeSync = NULL;
 uint64_t nLocalHostNonce = 0;
 static std::vector<ListenSocket> vhListenSocket;
 CAddrMan addrman;
@@ -519,10 +518,6 @@ void CNode::CloseSocketDisconnect()
     TRY_LOCK(cs_vRecvMsg, lockRecv);
     if (lockRecv)
         vRecvMsg.clear();
-
-    // if this was the sync node, we'll need a new one
-    if (this == pnodeSync)
-        pnodeSync = NULL;
 }
 
 void CNode::PushVersion()
@@ -615,7 +610,6 @@ void CNode::copyStats(CNodeStats &stats)
     X(nSendBytes);
     X(nRecvBytes);
     X(fWhitelisted);
-    stats.fSyncNode = (this == pnodeSync);
 
     // It is common for nodes with good ping times to suddenly become lagged,
     // due to a new block arriving or other large transfer.
@@ -1487,61 +1481,20 @@ bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOu
 }
 
 
-// for now, use a very simple selection metric: the node from which we received
-// most recently
-static int64_t NodeSyncScore(const CNode *pnode) {
-    return pnode->nLastRecv;
-}
-
-void static StartSync(const vector<CNode*> &vNodes) {
-    CNode *pnodeNewSync = NULL;
-    int64_t nBestScore = 0;
-
-    int nBestHeight = g_signals.GetHeight().get_value_or(0);
-
-    // Iterate over all nodes
-    BOOST_FOREACH(CNode* pnode, vNodes) {
-        // check preconditions for allowing a sync
-        if (!pnode->fClient && !pnode->fOneShot &&
-            !pnode->fDisconnect && pnode->fSuccessfullyConnected &&
-            (pnode->nStartingHeight > (nBestHeight - 144)) &&
-            (pnode->nVersion < NOBLKS_VERSION_START || pnode->nVersion >= NOBLKS_VERSION_END)) {
-            // if ok, compare node's score with the best so far
-            int64_t nScore = NodeSyncScore(pnode);
-            if (pnodeNewSync == NULL || nScore > nBestScore) {
-                pnodeNewSync = pnode;
-                nBestScore = nScore;
-            }
-        }
-    }
-    // if a new sync candidate was found, start sync!
-    if (pnodeNewSync) {
-        pnodeNewSync->fStartSync = true;
-        pnodeSync = pnodeNewSync;
-    }
-}
-
 void ThreadMessageHandler()
 {
     SetThreadPriority(THREAD_PRIORITY_BELOW_NORMAL);
     while (true)
     {
-        bool fHaveSyncNode = false;
-
         vector<CNode*> vNodesCopy;
         {
             LOCK(cs_vNodes);
             vNodesCopy = vNodes;
             BOOST_FOREACH(CNode* pnode, vNodesCopy) {
                 pnode->AddRef();
-                if (pnode == pnodeSync)
-                    fHaveSyncNode = true;
             }
         }
 
-        if (!fHaveSyncNode)
-            StartSync(vNodesCopy);
-
         // Poll the connected nodes for messages
         CNode* pnodeTrickle = NULL;
         if (!vNodesCopy.empty())
@@ -2078,10 +2031,7 @@ CNode::CNode(SOCKET hSocketIn, CAddress addrIn, std::string addrNameIn, bool fIn
     nSendSize = 0;
     nSendOffset = 0;
     hashContinue = 0;
-    pindexLastGetBlocksBegin = 0;
-    hashLastGetBlocksEnd = 0;
     nStartingHeight = -1;
-    fStartSync = false;
     fGetAddr = false;
     fRelayTxes = false;
     setInventoryKnown.max_size(SendBufferSize() / 1000);

src/net.h

@@ -158,7 +158,6 @@ public:
     int nStartingHeight;
     uint64_t nSendBytes;
     uint64_t nRecvBytes;
-    bool fSyncNode;
     bool fWhitelisted;
     double dPingTime;
     double dPingWait;
@@ -276,10 +275,7 @@ protected:
 
 public:
     uint256 hashContinue;
-    CBlockIndex* pindexLastGetBlocksBegin;
-    uint256 hashLastGetBlocksEnd;
     int nStartingHeight;
-    bool fStartSync;
 
     // flood relay
     std::vector<CAddress> vAddrToSend;

src/pow.cpp

@@ -98,39 +98,6 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits)
     return true;
 }
 
-//
-// true if nBits is greater than the minimum amount of work that could
-// possibly be required deltaTime after minimum work required was nBase
-//
-bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime)
-{
-    bool fOverflow = false;
-    uint256 bnNewBlock;
-    bnNewBlock.SetCompact(nBits, NULL, &fOverflow);
-    if (fOverflow)
-        return false;
-
-    const uint256 &bnLimit = Params().ProofOfWorkLimit();
-    // Testnet has min-difficulty blocks
-    // after Params().TargetSpacing()*2 time between blocks:
-    if (Params().AllowMinDifficultyBlocks() && deltaTime > Params().TargetSpacing()*2)
-        return bnNewBlock <= bnLimit;
-
-    uint256 bnResult;
-    bnResult.SetCompact(nBase);
-    while (deltaTime > 0 && bnResult < bnLimit)
-    {
-        // Maximum 400% adjustment...
-        bnResult *= 4;
-        // ... in best-case exactly 4-times-normal target time
-        deltaTime -= Params().TargetTimespan()*4;
-    }
-    if (bnResult > bnLimit)
-        bnResult = bnLimit;
-
-    return bnNewBlock <= bnResult;
-}
-
 void UpdateTime(CBlockHeader* pblock, const CBlockIndex* pindexPrev)
 {
     pblock->nTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());

src/pow.h

@@ -16,8 +16,6 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
 
 /** Check whether a block hash satisfies the proof-of-work requirement specified by nBits */
 bool CheckProofOfWork(uint256 hash, unsigned int nBits);
-/** Check the work is more than the minimum a received block needs, without knowing its direct parent */
-bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime);
 
 void UpdateTime(CBlockHeader* block, const CBlockIndex* pindexPrev);
 

src/qt/forms/rpcconsole.ui

@@ -836,29 +836,6 @@
             </property>
            </widget>
           </item>
-          <item row="4" column="0">
-           <widget class="QLabel" name="label_25">
-            <property name="text">
-             <string>Sync Node</string>
-            </property>
-           </widget>
-          </item>
-          <item row="4" column="2">
-           <widget class="QLabel" name="peerSyncNode">
-            <property name="cursor">
-             <cursorShape>IBeamCursor</cursorShape>
-            </property>
-            <property name="text">
-             <string>N/A</string>
-            </property>
-            <property name="textFormat">
-             <enum>Qt::PlainText</enum>
-            </property>
-            <property name="textInteractionFlags">
-             <set>Qt::LinksAccessibleByMouse|Qt::TextSelectableByKeyboard|Qt::TextSelectableByMouse</set>
-            </property>
-           </widget>
-          </item>
           <item row="5" column="0">
            <widget class="QLabel" name="label_29">
             <property name="text">

src/qt/rpcconsole.cpp

@@ -611,7 +611,6 @@ void RPCConsole::updateNodeDetail(const CNodeCombinedStats *stats)
     ui->peerSubversion->setText(QString::fromStdString(stats->nodeStats.cleanSubVer));
     ui->peerDirection->setText(stats->nodeStats.fInbound ? tr("Inbound") : tr("Outbound"));
     ui->peerHeight->setText(QString("%1").arg(stats->nodeStats.nStartingHeight));
-    ui->peerSyncNode->setText(stats->nodeStats.fSyncNode ? tr("Yes") : tr("No"));
 
     // This check fails for example if the lock was busy and
     // nodeStateStats couldn't be fetched.

src/rpcblockchain.cpp

@@ -445,6 +445,7 @@ Value getblockchaininfo(const Array& params, bool fHelp)
             "{\n"
             "  \"chain\": \"xxxx\",        (string) current network name as defined in BIP70 (main, test, regtest)\n"
             "  \"blocks\": xxxxxx,         (numeric) the current number of blocks processed in the server\n"
+            "  \"headers\": xxxxxx,        (numeric) the current number of headers we have validated\n"
             "  \"bestblockhash\": \"...\", (string) the hash of the currently best block\n"
             "  \"difficulty\": xxxxxx,     (numeric) the current difficulty\n"
             "  \"verificationprogress\": xxxx, (numeric) estimate of verification progress [0..1]\n"
@@ -458,6 +459,7 @@ Value getblockchaininfo(const Array& params, bool fHelp)
     Object obj;
     obj.push_back(Pair("chain",                 Params().NetworkIDString()));
     obj.push_back(Pair("blocks",                (int)chainActive.Height()));
+    obj.push_back(Pair("headers",               pindexBestHeader ? pindexBestHeader->nHeight : -1));
     obj.push_back(Pair("bestblockhash",         chainActive.Tip()->GetBlockHash().GetHex()));
     obj.push_back(Pair("difficulty",            (double)GetDifficulty()));
     obj.push_back(Pair("verificationprogress",  Checkpoints::GuessVerificationProgress(chainActive.Tip())));

src/rpcnet.cpp

@@ -97,7 +97,12 @@ Value getpeerinfo(const Array& params, bool fHelp)
             "    \"inbound\": true|false,     (boolean) Inbound (true) or Outbound (false)\n"
             "    \"startingheight\": n,       (numeric) The starting height (block) of the peer\n"
             "    \"banscore\": n,             (numeric) The ban score\n"
-            "    \"syncnode\": true|false     (boolean) if sync node\n"
+            "    \"synced_headers\": n,       (numeric) The last header we have in common with this peer\n"
+            "    \"synced_blocks\": n,        (numeric) The last block we have in common with this peer\n"
+            "    \"inflight\": [\n"
+            "       n,                        (numeric) The heights of blocks we're currently asking from this peer\n"
+            "       ...\n"
+            "    ]\n"
             "  }\n"
             "  ,...\n"
             "]\n"
@@ -137,9 +142,14 @@ Value getpeerinfo(const Array& params, bool fHelp)
         obj.push_back(Pair("startingheight", stats.nStartingHeight));
         if (fStateStats) {
             obj.push_back(Pair("banscore", statestats.nMisbehavior));
-            obj.push_back(Pair("syncheight", statestats.nSyncHeight));
+            obj.push_back(Pair("synced_headers", statestats.nSyncHeight));
+            obj.push_back(Pair("synced_blocks", statestats.nCommonHeight));
+            Array heights;
+            BOOST_FOREACH(int height, statestats.vHeightInFlight) {
+                heights.push_back(height);
+            }
+            obj.push_back(Pair("inflight", heights));
         }
-        obj.push_back(Pair("syncnode", stats.fSyncNode));
         obj.push_back(Pair("whitelisted", stats.fWhitelisted));
 
         ret.push_back(obj);

src/test/DoS_tests.cpp

@@ -106,51 +106,6 @@ BOOST_AUTO_TEST_CASE(DoS_bantime)
     BOOST_CHECK(!CNode::IsBanned(addr));
 }
 
-static bool CheckNBits(unsigned int nbits1, int64_t time1, unsigned int nbits2, int64_t time2)\
-{
-    if (time1 > time2)
-        return CheckNBits(nbits2, time2, nbits1, time1);
-    int64_t deltaTime = time2-time1;
-
-    return CheckMinWork(nbits2, nbits1, deltaTime);
-}
-
-BOOST_AUTO_TEST_CASE(DoS_checknbits)
-{
-    using namespace boost::assign; // for 'map_list_of()'
-
-    // Timestamps,nBits from the bitcoin block chain.
-    // These are the block-chain checkpoint blocks
-    typedef std::map<int64_t, unsigned int> BlockData;
-    BlockData chainData =
-        map_list_of(1239852051,486604799)(1262749024,486594666)
-        (1279305360,469854461)(1280200847,469830746)(1281678674,469809688)
-        (1296207707,453179945)(1302624061,453036989)(1309640330,437004818)
-        (1313172719,436789733);
-
-    // Make sure CheckNBits considers every combination of block-chain-lock-in-points
-    // "sane":
-    BOOST_FOREACH(const BlockData::value_type& i, chainData)
-    {
-        BOOST_FOREACH(const BlockData::value_type& j, chainData)
-        {
-            BOOST_CHECK(CheckNBits(i.second, i.first, j.second, j.first));
-        }
-    }
-
-    // Test a couple of insane combinations:
-    BlockData::value_type firstcheck = *(chainData.begin());
-    BlockData::value_type lastcheck = *(chainData.rbegin());
-
-    // First checkpoint difficulty at or a while after the last checkpoint time should fail when
-    // compared to last checkpoint
-    BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*10, lastcheck.second, lastcheck.first));
-    BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*60*24*14, lastcheck.second, lastcheck.first));
-
-    // ... but OK if enough time passed for difficulty to adjust downward:
-    BOOST_CHECK(CheckNBits(firstcheck.second, lastcheck.first+60*60*24*365*4, lastcheck.second, lastcheck.first));
-}
-
 CTransaction RandomOrphan()
 {
     std::map<uint256, COrphanTx>::iterator it;

src/version.h

@@ -33,8 +33,11 @@ static const int PROTOCOL_VERSION = 70002;
 // initial proto version, to be increased after version/verack negotiation
 static const int INIT_PROTO_VERSION = 209;
 
+// In this version, 'getheaders' was introduced.
+static const int GETHEADERS_VERSION = 31800;
+
 // disconnect from peers older than this proto version
-static const int MIN_PEER_PROTO_VERSION = 209;
+static const int MIN_PEER_PROTO_VERSION = GETHEADERS_VERSION;
 
 // nTime field added to CAddress, starting with this version;
 // if possible, avoid requesting addresses nodes older than this