highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-01-20 07:09:15 +01:00
Code Issues Packages Projects Releases Wiki Activity

Merge #15759: p2p: Add 2 outbound block-relay-only connections

Browse Source 
0ba08020c9 Disconnect peers violating blocks-only mode (Suhas Daftuar)
937eba91e1 doc: improve comments relating to block-relay-only peers (Suhas Daftuar)
430f489027 Don't relay addr messages to block-relay-only peers (Suhas Daftuar)
3a5e885306 Add 2 outbound block-relay-only connections (Suhas Daftuar)
b83f51a4bb Add comment explaining intended use of m_tx_relay (Suhas Daftuar)
e75c39cd42 Check that tx_relay is initialized before access (Suhas Daftuar)
c4aa2ba822 [refactor] Change tx_relay structure to be unique_ptr (Suhas Daftuar)
4de0dbac9b [refactor] Move tx relay state to separate structure (Suhas Daftuar)
26a93bce29 Remove unused variable (Suhas Daftuar)

Pull request description:

  Transaction relay is optimized for a combination of redundancy/robustness as well as bandwidth minimization -- as a result transaction relay leaks information that adversaries can use to infer the network topology.

  Network topology is better kept private for (at least) two reasons:

  (a) Knowledge of the network graph can make it easier to find the source IP of a given transaction.

  (b) Knowledge of the network graph could be used to split a target node or nodes from the honest network (eg by knowing which peers to attack in order to achieve a network split).

  We can eliminate the risks of (b) by separating block relay from transaction relay; inferring network connectivity from the relay of blocks/block headers is much more expensive for an adversary.

  After this commit, bitcoind will make 2 additional outbound connections that are only used for block relay. (In the future, we might consider rotating our transaction-relay peers to help limit the effects of (a).)

ACKs for top commit:
  sipa:
    ACK 0ba08020c9
  ajtowns:
    ACK 0ba08020c9 -- code review, ran tests. ran it on mainnet for a couple of days with MAX_BLOCKS_ONLY_CONNECTIONS upped from 2 to 16 and didn't observe any unexpected behaviour: it disconnected a couple of peers that tried sending inv's, and it successfully did compact block relay with some block relay peers.
  TheBlueMatt:
    re-utACK 0ba08020c9. Pointed out that stats.fRelayTxes was sometimes uninitialized for blocksonly peers (though its not a big deal and only effects RPC), which has since been fixed here. Otherwise changes are pretty trivial so looks good.
  jnewbery:
    utACK 0ba08020c9
  jamesob:
    ACK 0ba08020c9

Tree-SHA512: 4c3629434472c7dd4125253417b1be41967a508c3cfec8af5a34cad685464fbebbb6558f0f8f5c0d4463e3ffa4fa3aabd58247692cb9ab8395f4993078b9bcdf
This commit is contained in:
fanquake
2019-09-07 17:24:05 +08:00
parent b5a8d0cff1 0ba08020c9
commit 189c19e012
6 changed files with 318 additions and 231 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
src/net.cpp
View File

@@ -352,7 +352,7 @@ static CAddress GetBindAddress(SOCKET sock)
return addr_bind;
}
CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure, bool manual_connection)
CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure, bool manual_connection, bool block_relay_only)
{
if (pszDest == nullptr) {
if (IsLocal(addrConnect))
@@ -442,7 +442,7 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
NodeId id = GetNewNodeId();
uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
CAddress addr_bind = GetBindAddress(hSocket);
CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addrConnect, CalculateKeyedNetGroup(addrConnect), nonce, addr_bind, pszDest ? pszDest : "", false);
CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addrConnect, CalculateKeyedNetGroup(addrConnect), nonce, addr_bind, pszDest ? pszDest : "", false, block_relay_only);
pnode->AddRef();
return pnode;
@@ -499,9 +499,11 @@ void CNode::copyStats(CNodeStats &stats)
X(nServices);
X(addr);
X(addrBind);
{
LOCK(cs_filter);
X(fRelayTxes);
if (m_tx_relay != nullptr) {
LOCK(m_tx_relay->cs_filter);
stats.fRelayTxes = m_tx_relay->fRelayTxes;
} else {
stats.fRelayTxes = false;
}
X(nLastSend);
X(nLastRecv);
@@ -528,9 +530,11 @@ void CNode::copyStats(CNodeStats &stats)
}
X(m_legacyWhitelisted);
X(m_permissionFlags);
{
LOCK(cs_feeFilter);
X(minFeeFilter);
if (m_tx_relay != nullptr) {
LOCK(m_tx_relay->cs_feeFilter);
stats.minFeeFilter = m_tx_relay->minFeeFilter;
} else {
stats.minFeeFilter = 0;
}
// It is common for nodes with good ping times to suddenly become lagged,
@@ -818,11 +822,17 @@ bool CConnman::AttemptToEvictConnection()
continue;
if (node->fDisconnect)
continue;
LOCK(node->cs_filter);
bool peer_relay_txes = false;
bool peer_filter_not_null = false;
if (node->m_tx_relay != nullptr) {
LOCK(node->m_tx_relay->cs_filter);
peer_relay_txes = node->m_tx_relay->fRelayTxes;
peer_filter_not_null = node->m_tx_relay->pfilter != nullptr;
}
NodeEvictionCandidate candidate = {node->GetId(), node->nTimeConnected, node->nMinPingUsecTime,
node->nLastBlockTime, node->nLastTXTime,
HasAllDesirableServiceFlags(node->nServices),
node->fRelayTxes, node->pfilter != nullptr, node->addr, node->nKeyedNetGroup,
peer_relay_txes, peer_filter_not_null, node->addr, node->nKeyedNetGroup,
node->m_prefer_evict};
vEvictionCandidates.push_back(candidate);
}
@@ -895,7 +905,7 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
SOCKET hSocket = accept(hListenSocket.socket, (struct sockaddr*)&sockaddr, &len);
CAddress addr;
int nInbound = 0;
int nMaxInbound = nMaxConnections - (nMaxOutbound + nMaxFeeler);
int nMaxInbound = nMaxConnections - m_max_outbound;
if (hSocket != INVALID_SOCKET) {
if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr)) {
@@ -1655,7 +1665,7 @@ int CConnman::GetExtraOutboundCount()
}
}
}
return std::max(nOutbound - nMaxOutbound, 0);
return std::max(nOutbound - m_max_outbound_full_relay - m_max_outbound_block_relay, 0);
}
void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
@@ -1715,7 +1725,8 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
CAddress addrConnect;
// Only connect out to one peer per network group (/16 for IPv4).
int nOutbound = 0;
int nOutboundFullRelay = 0;
int nOutboundBlockRelay = 0;
std::set<std::vector<unsigned char> > setConnected;
{
LOCK(cs_vNodes);
@@ -1727,7 +1738,11 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
// also have the added issue that they're attacker controlled and could be used
// to prevent us from connecting to particular hosts if we used them here.
setConnected.insert(pnode->addr.GetGroup());
nOutbound++;
if (pnode->m_tx_relay == nullptr) {
nOutboundBlockRelay++;
} else if (!pnode->fFeeler) {
nOutboundFullRelay++;
}
}
}
}
@@ -1746,7 +1761,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
//
bool fFeeler = false;
if (nOutbound >= nMaxOutbound && !GetTryNewOutboundPeer()) {
if (nOutboundFullRelay >= m_max_outbound_full_relay && nOutboundBlockRelay >= m_max_outbound_block_relay && !GetTryNewOutboundPeer()) {
int64_t nTime = GetTimeMicros(); // The current time right now (in microseconds).
if (nTime > nNextFeeler) {
nNextFeeler = PoissonNextSend(nTime, FEELER_INTERVAL);
@@ -1820,7 +1835,14 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
LogPrint(BCLog::NET, "Making feeler connection to %s\n", addrConnect.ToString());
}
OpenNetworkConnection(addrConnect, (int)setConnected.size() >= std::min(nMaxConnections - 1, 2), &grant, nullptr, false, fFeeler);
// Open this connection as block-relay-only if we're already at our
// full-relay capacity, but not yet at our block-relay peer limit.
// (It should not be possible for fFeeler to be set if we're not
// also at our block-relay peer limit, but check against that as
// well for sanity.)
bool block_relay_only = nOutboundBlockRelay < m_max_outbound_block_relay && !fFeeler && nOutboundFullRelay >= m_max_outbound_full_relay;
OpenNetworkConnection(addrConnect, (int)setConnected.size() >= std::min(nMaxConnections - 1, 2), &grant, nullptr, false, fFeeler, false, block_relay_only);
}
}
}
@@ -1907,7 +1929,7 @@ void CConnman::ThreadOpenAddedConnections()
}
// if successful, this moves the passed grant to the constructed node
void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot, bool fFeeler, bool manual_connection)
void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot, bool fFeeler, bool manual_connection, bool block_relay_only)
{
//
// Initiate outbound network connection
@@ -1926,7 +1948,7 @@ void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai
} else if (FindNode(std::string(pszDest)))
return;
CNode* pnode = ConnectNode(addrConnect, pszDest, fCountFailure, manual_connection);
CNode* pnode = ConnectNode(addrConnect, pszDest, fCountFailure, manual_connection, block_relay_only);
if (!pnode)
return;
@@ -2229,7 +2251,7 @@ bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
if (semOutbound == nullptr) {
// initialize semaphore
semOutbound = MakeUnique<CSemaphore>(std::min((nMaxOutbound + nMaxFeeler), nMaxConnections));
semOutbound = MakeUnique<CSemaphore>(std::min(m_max_outbound, nMaxConnections));
}
if (semAddnode == nullptr) {
// initialize semaphore
@@ -2307,7 +2329,7 @@ void CConnman::Interrupt()
InterruptSocks5(true);
if (semOutbound) {
for (int i=0; i<(nMaxOutbound + nMaxFeeler); i++) {
for (int i=0; i<m_max_outbound; i++) {
semOutbound->post();
}
}
@@ -2617,14 +2639,17 @@ int CConnman::GetBestHeight() const
unsigned int CConnman::GetReceiveFloodSize() const { return nReceiveFloodSize; }
CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn, SOCKET hSocketIn, const CAddress& addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const CAddress& addrBindIn, const std::string& addrNameIn, bool fInboundIn)
CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn, SOCKET hSocketIn, const CAddress& addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const CAddress& addrBindIn, const std::string& addrNameIn, bool fInboundIn, bool block_relay_only)
: nTimeConnected(GetSystemTimeInSeconds()),
addr(addrIn),
addrBind(addrBindIn),
fInbound(fInboundIn),
nKeyedNetGroup(nKeyedNetGroupIn),
addrKnown(5000, 0.001),
filterInventoryKnown(50000, 0.000001),
// Don't relay addr messages to peers that we connect to as block-relay-only
// peers (to prevent adversaries from inferring these links from addr
// traffic).
m_addr_relay_peer(!block_relay_only),
id(idIn),
nLocalHostNonce(nLocalHostNonceIn),
nLocalServices(nLocalServicesIn),
@@ -2633,8 +2658,9 @@ CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn
hSocket = hSocketIn;
addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
hashContinue = uint256();
filterInventoryKnown.reset();
pfilter = MakeUnique<CBloomFilter>();
if (!block_relay_only) {
m_tx_relay = MakeUnique<TxRelay>();
}
for (const std::string &msg : getAllNetMessageTypes())
mapRecvBytesPerMsgCmd[msg] = 0;