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Merge pull request #6715

60de0d5 Fix mempool package tracking edge case (Suhas Daftuar)
598b25d Add test showing bug in mempool packages (Suhas Daftuar)
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laanwj committed Sep 24, 2015
2 parents 5b77244 + 60de0d5 commit 82d2aef7b3e05abda81db03a8d4725d52f06f203
Showing with 121 additions and 27 deletions.
  1. +82 −11 qa/rpc-tests/mempool_packages.py
  2. +36 −15 src/txmempool.cpp
  3. +3 −1 src/txmempool.h
@@ -15,22 +15,24 @@ class MempoolPackagesTest(BitcoinTestFramework):

def setup_network(self):
self.nodes = []
self.nodes.append(start_node(0, self.options.tmpdir, ["-maxorphantx=1000", "-relaypriority=0"]))
self.nodes.append(start_node(0, self.options.tmpdir, ["-maxorphantx=1000", "-relaypriority=0", "-debug"]))
self.nodes.append(start_node(1, self.options.tmpdir, ["-maxorphantx=1000", "-relaypriority=0", "-limitancestorcount=5", "-debug"]))
connect_nodes(self.nodes[0], 1)
self.is_network_split = False
self.sync_all()

# Build a transaction that spends parent_txid:vout
# Return amount sent
def chain_transaction(self, parent_txid, vout, value, fee, num_outputs):
def chain_transaction(self, node, parent_txid, vout, value, fee, num_outputs):
send_value = satoshi_round((value - fee)/num_outputs)
inputs = [ {'txid' : parent_txid, 'vout' : vout} ]
outputs = {}
for i in xrange(num_outputs):
outputs[self.nodes[0].getnewaddress()] = send_value
rawtx = self.nodes[0].createrawtransaction(inputs, outputs)
signedtx = self.nodes[0].signrawtransaction(rawtx)
txid = self.nodes[0].sendrawtransaction(signedtx['hex'])
fulltx = self.nodes[0].getrawtransaction(txid, 1)
outputs[node.getnewaddress()] = send_value
rawtx = node.createrawtransaction(inputs, outputs)
signedtx = node.signrawtransaction(rawtx)
txid = node.sendrawtransaction(signedtx['hex'])
fulltx = node.getrawtransaction(txid, 1)
assert(len(fulltx['vout']) == num_outputs) # make sure we didn't generate a change output
return (txid, send_value)

@@ -46,7 +48,7 @@ def run_test(self):
# 100 transactions off a confirmed tx should be fine
chain = []
for i in xrange(100):
(txid, sent_value) = self.chain_transaction(txid, 0, value, fee, 1)
(txid, sent_value) = self.chain_transaction(self.nodes[0], txid, 0, value, fee, 1)
value = sent_value
chain.append(txid)

@@ -69,10 +71,12 @@ def run_test(self):

# Adding one more transaction on to the chain should fail.
try:
self.chain_transaction(txid, vout, value, fee, 1)
self.chain_transaction(self.nodes[0], txid, vout, value, fee, 1)
except JSONRPCException as e:
print "too-long-ancestor-chain successfully rejected"

# TODO: check that node1's mempool is as expected

# TODO: test ancestor size limits

# Now test descendant chain limits
@@ -82,15 +86,15 @@ def run_test(self):

transaction_package = []
# First create one parent tx with 10 children
(txid, sent_value) = self.chain_transaction(txid, vout, value, fee, 10)
(txid, sent_value) = self.chain_transaction(self.nodes[0], txid, vout, value, fee, 10)
parent_transaction = txid
for i in xrange(10):
transaction_package.append({'txid': txid, 'vout': i, 'amount': sent_value})

for i in xrange(1000):
utxo = transaction_package.pop(0)
try:
(txid, sent_value) = self.chain_transaction(utxo['txid'], utxo['vout'], utxo['amount'], fee, 10)
(txid, sent_value) = self.chain_transaction(self.nodes[0], utxo['txid'], utxo['vout'], utxo['amount'], fee, 10)
for j in xrange(10):
transaction_package.append({'txid': txid, 'vout': j, 'amount': sent_value})
if i == 998:
@@ -101,7 +105,74 @@ def run_test(self):
assert_equal(i, 999)
print "tx that would create too large descendant package successfully rejected"

# TODO: check that node1's mempool is as expected

# TODO: test descendant size limits

# Test reorg handling
# First, the basics:
self.nodes[0].generate(1)
sync_blocks(self.nodes)
self.nodes[1].invalidateblock(self.nodes[0].getbestblockhash())
self.nodes[1].reconsiderblock(self.nodes[0].getbestblockhash())

# Now test the case where node1 has a transaction T in its mempool that
# depends on transactions A and B which are in a mined block, and the
# block containing A and B is disconnected, AND B is not accepted back
# into node1's mempool because its ancestor count is too high.

# Create 8 transactions, like so:
# Tx0 -> Tx1 (vout0)
# \--> Tx2 (vout1) -> Tx3 -> Tx4 -> Tx5 -> Tx6 -> Tx7
#
# Mine them in the next block, then generate a new tx8 that spends
# Tx1 and Tx7, and add to node1's mempool, then disconnect the
# last block.

# Create tx0 with 2 outputs
utxo = self.nodes[0].listunspent()
txid = utxo[0]['txid']
value = utxo[0]['amount']
vout = utxo[0]['vout']

send_value = satoshi_round((value - fee)/2)
inputs = [ {'txid' : txid, 'vout' : vout} ]
outputs = {}
for i in xrange(2):
outputs[self.nodes[0].getnewaddress()] = send_value
rawtx = self.nodes[0].createrawtransaction(inputs, outputs)
signedtx = self.nodes[0].signrawtransaction(rawtx)
txid = self.nodes[0].sendrawtransaction(signedtx['hex'])
tx0_id = txid
value = send_value

# Create tx1
(tx1_id, tx1_value) = self.chain_transaction(self.nodes[0], tx0_id, 0, value, fee, 1)

# Create tx2-7
vout = 1
txid = tx0_id
for i in xrange(6):
(txid, sent_value) = self.chain_transaction(self.nodes[0], txid, vout, value, fee, 1)
vout = 0
value = sent_value

# Mine these in a block
self.nodes[0].generate(1)
self.sync_all()

# Now generate tx8, with a big fee
inputs = [ {'txid' : tx1_id, 'vout': 0}, {'txid' : txid, 'vout': 0} ]
outputs = { self.nodes[0].getnewaddress() : send_value + value - 4*fee }
rawtx = self.nodes[0].createrawtransaction(inputs, outputs)
signedtx = self.nodes[0].signrawtransaction(rawtx)
txid = self.nodes[0].sendrawtransaction(signedtx['hex'])
sync_mempools(self.nodes)

# Now try to disconnect the tip on each node...
self.nodes[1].invalidateblock(self.nodes[1].getbestblockhash())
self.nodes[0].invalidateblock(self.nodes[0].getbestblockhash())
sync_blocks(self.nodes)

if __name__ == '__main__':
MempoolPackagesTest().main()
@@ -159,26 +159,30 @@ void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256> &vHashes
}
}

bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString)
bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents /* = true */)
{
setEntries parentHashes;
const CTransaction &tx = entry.GetTx();

// Get parents of this transaction that are in the mempool
// Entry may or may not already be in the mempool, and GetMemPoolParents()
// is only valid for entries in the mempool, so we iterate mapTx to find
// parents.
// TODO: optimize this so that we only check limits and walk
// tx.vin when called on entries not already in the mempool.
for (unsigned int i = 0; i < tx.vin.size(); i++) {
txiter piter = mapTx.find(tx.vin[i].prevout.hash);
if (piter != mapTx.end()) {
parentHashes.insert(piter);
if (parentHashes.size() + 1 > limitAncestorCount) {
errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
return false;
if (fSearchForParents) {
// Get parents of this transaction that are in the mempool
// GetMemPoolParents() is only valid for entries in the mempool, so we
// iterate mapTx to find parents.
for (unsigned int i = 0; i < tx.vin.size(); i++) {
txiter piter = mapTx.find(tx.vin[i].prevout.hash);
if (piter != mapTx.end()) {
parentHashes.insert(piter);
if (parentHashes.size() + 1 > limitAncestorCount) {
errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
return false;
}
}
}
} else {
// If we're not searching for parents, we require this to be an
// entry in the mempool already.
txiter it = mapTx.iterator_to(entry);
parentHashes = GetMemPoolParents(it);
}

size_t totalSizeWithAncestors = entry.GetTxSize();
@@ -249,7 +253,24 @@ void CTxMemPool::UpdateForRemoveFromMempool(const setEntries &entriesToRemove)
setEntries setAncestors;
const CTxMemPoolEntry &entry = *removeIt;
std::string dummy;
CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy);
// Since this is a tx that is already in the mempool, we can call CMPA
// with fSearchForParents = false. If the mempool is in a consistent
// state, then using true or false should both be correct, though false
// should be a bit faster.
// However, if we happen to be in the middle of processing a reorg, then
// the mempool can be in an inconsistent state. In this case, the set
// of ancestors reachable via mapLinks will be the same as the set of
// ancestors whose packages include this transaction, because when we
// add a new transaction to the mempool in addUnchecked(), we assume it
// has no children, and in the case of a reorg where that assumption is
// false, the in-mempool children aren't linked to the in-block tx's
// until UpdateTransactionsFromBlock() is called.
// So if we're being called during a reorg, ie before
// UpdateTransactionsFromBlock() has been called, then mapLinks[] will
// differ from the set of mempool parents we'd calculate by searching,
// and it's important that we use the mapLinks[] notion of ancestor
// transactions as the set of things to update for removal.
CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy, false);
// Note that UpdateAncestorsOf severs the child links that point to
// removeIt in the entries for the parents of removeIt. This is
// fine since we don't need to use the mempool children of any entries
@@ -392,8 +392,10 @@ class CTxMemPool
* limitDescendantCount = max number of descendants any ancestor can have
* limitDescendantSize = max size of descendants any ancestor can have
* errString = populated with error reason if any limits are hit
* fSearchForParents = whether to search a tx's vin for in-mempool parents, or
* look up parents from mapLinks. Must be true for entries not in the mempool
*/
bool CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString);
bool CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents = true);

unsigned long size()
{

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