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Add recently accepted blocks and txn to AttemptToEvictConnection.

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This protects any not-already-protected peers who were the most
 recent four to relay transactions and most recent four to send
 blocks to us.
This commit is contained in:
Gregory Maxwell 2016-05-22 05:55:15 +00:00
parent 32b7294177
commit 5d0ca81f74
4 changed files with 61 additions and 10 deletions
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16
src/main.cpp
View file

@ -3449,8 +3449,9 @@ static bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state
}
/** Store block on disk. If dbp is non-NULL, the file is known to already reside on disk */
static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp)
static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock)
{
if (fNewBlock) *fNewBlock = false;
AssertLockHeld(cs_main);
CBlockIndex *pindexDummy = NULL;
@ -3479,6 +3480,7 @@ static bool AcceptBlock(const CBlock& block, CValidationState& state, const CCha
if (!fHasMoreWork) return true; // Don't process less-work chains
if (fTooFarAhead) return true; // Block height is too high
}
if (fNewBlock) *fNewBlock = true;
if ((!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime())) || !ContextualCheckBlock(block, state, pindex->pprev)) {
if (state.IsInvalid() && !state.CorruptionPossible()) {
@ -3526,7 +3528,7 @@ static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned
}
bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
{
{
LOCK(cs_main);
@ -3535,9 +3537,11 @@ bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, c
// Store to disk
CBlockIndex *pindex = NULL;
bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fRequested, dbp);
bool fNewBlock = false;
bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fRequested, dbp, &fNewBlock);
if (pindex && pfrom) {
mapBlockSource[pindex->GetBlockHash()] = pfrom->GetId();
if (fNewBlock) pfrom->nLastBlockTime = GetTime();
}
CheckBlockIndex(chainparams.GetConsensus());
if (!ret)
@ -4107,7 +4111,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
if (mapBlockIndex.count(hash) == 0 || (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
LOCK(cs_main);
CValidationState state;
if (AcceptBlock(block, state, chainparams, NULL, true, dbp))
if (AcceptBlock(block, state, chainparams, NULL, true, dbp, NULL))
nLoaded++;
if (state.IsError())
break;
@ -4140,7 +4144,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
head.ToString());
LOCK(cs_main);
CValidationState dummy;
if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second))
if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second, NULL))
{
nLoaded++;
queue.push_back(block.GetHash());
@ -5040,6 +5044,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
RelayTransaction(tx);
vWorkQueue.push_back(inv.hash);
pfrom->nLastTXTime = GetTime();
LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n",
pfrom->id,
tx.GetHash().ToString(),

2
src/main.h
View file

@ -215,7 +215,7 @@ void UnregisterNodeSignals(CNodeSignals& nodeSignals);
* @param[out] dbp The already known disk position of pblock, or NULL if not yet stored.
* @return True if state.IsValid()
*/
bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp);
bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp);
/** Check whether enough disk space is available for an incoming block */
bool CheckDiskSpace(uint64_t nAdditionalBytes = 0);
/** Open a block file (blk?????.dat) */

48
src/net.cpp
View file

@ -838,6 +838,11 @@ struct NodeEvictionCandidate
NodeId id;
int64_t nTimeConnected;
int64_t nMinPingUsecTime;
int64_t nLastBlockTime;
int64_t nLastTXTime;
bool fNetworkNode;
bool fRelayTxes;
bool fBloomFilter;
CAddress addr;
uint64_t nKeyedNetGroup;
};
@ -854,7 +859,24 @@ static bool ReverseCompareNodeTimeConnected(const NodeEvictionCandidate &a, cons
static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) {
return a.nKeyedNetGroup < b.nKeyedNetGroup;
};
}
static bool CompareNodeBlockTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
{
// There is a fall-through here because it is common for a node to have many peers which have not yet relayed a block.
if (a.nLastBlockTime != b.nLastBlockTime) return a.nLastBlockTime < b.nLastBlockTime;
if (a.fNetworkNode != b.fNetworkNode) return b.fNetworkNode;
return a.nTimeConnected > b.nTimeConnected;
}
static bool CompareNodeTXTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
{
// There is a fall-through here because it is common for a node to have more than a few peers that have not yet relayed txn.
if (a.nLastTXTime != b.nLastTXTime) return a.nLastTXTime < b.nLastTXTime;
if (a.fRelayTxes != b.fRelayTxes) return b.fRelayTxes;
if (a.fBloomFilter != b.fBloomFilter) return a.fBloomFilter;
return a.nTimeConnected > b.nTimeConnected;
}
/** Try to find a connection to evict when the node is full.
* Extreme care must be taken to avoid opening the node to attacker
@ -864,7 +886,7 @@ static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvict
* to forge. In order to partition a node the attacker must be
* simultaneously better at all of them than honest peers.
*/
static bool AttemptToEvictConnection(bool fPreferNewConnection) {
static bool AttemptToEvictConnection() {
std::vector<NodeEvictionCandidate> vEvictionCandidates;
{
LOCK(cs_vNodes);
@ -876,7 +898,9 @@ static bool AttemptToEvictConnection(bool fPreferNewConnection) {
continue;
if (node->fDisconnect)
continue;
NodeEvictionCandidate candidate = {node->id, node->nTimeConnected, node->nMinPingUsecTime, node->addr, node->nKeyedNetGroup};
NodeEvictionCandidate candidate = {node->id, node->nTimeConnected, node->nMinPingUsecTime,
node->nLastBlockTime, node->nLastTXTime, node->fNetworkNode,
node->fRelayTxes, node->pfilter != NULL, node->addr, node->nKeyedNetGroup};
vEvictionCandidates.push_back(candidate);
}
}
@ -899,6 +923,20 @@ static bool AttemptToEvictConnection(bool fPreferNewConnection) {
if (vEvictionCandidates.empty()) return false;
// Protect 4 nodes that most recently sent us transactions.
// An attacker cannot manipulate this metric without performing useful work.
std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeTXTime);
vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(4, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());
if (vEvictionCandidates.empty()) return false;
// Protect 4 nodes that most recently sent us blocks.
// An attacker cannot manipulate this metric without performing useful work.
std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeBlockTime);
vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(4, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());
if (vEvictionCandidates.empty()) return false;
// Protect the half of the remaining nodes which have been connected the longest.
// This replicates the non-eviction implicit behavior, and precludes attacks that start later.
std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeTimeConnected);
@ -999,7 +1037,7 @@ static void AcceptConnection(const ListenSocket& hListenSocket) {
if (nInbound >= nMaxInbound)
{
if (!AttemptToEvictConnection(whitelisted)) {
if (!AttemptToEvictConnection()) {
// No connection to evict, disconnect the new connection
LogPrint("net", "failed to find an eviction candidate - connection dropped (full)\n");
CloseSocket(hSocket);
@ -2358,6 +2396,8 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa
fSentAddr = false;
pfilter = new CBloomFilter();
timeLastMempoolReq = 0;
nLastBlockTime = 0;
nLastTXTime = 0;
nPingNonceSent = 0;
nPingUsecStart = 0;
nPingUsecTime = 0;

5
src/net.h
View file

@ -416,6 +416,11 @@ public:
// Last time a "MEMPOOL" request was serviced.
std::atomic<int64_t> timeLastMempoolReq;
// Block and TXN accept times
std::atomic<int64_t> nLastBlockTime;
std::atomic<int64_t> nLastTXTime;
// Ping time measurement:
// The pong reply we're expecting, or 0 if no pong expected.
uint64_t nPingNonceSent;