// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_NET_H
#define BITCOIN_NET_H
#include <addrman.h>
#include <amount.h>
#include <bloom.h>
#include <chainparams.h>
#include <compat.h>
#include <crypto/siphash.h>
#include <hash.h>
#include <i2p.h>
#include <net_permissions.h>
#include <netaddress.h>
#include <netbase.h>
#include <policy/feerate.h>
#include <protocol.h>
#include <random.h>
#include <span.h>
#include <streams.h>
#include <sync.h>
#include <threadinterrupt.h>
#include <uint256.h>
#include <util/check.h>
#include <atomic>
#include <condition_variable>
#include <cstdint>
#include <deque>
#include <map>
#include <memory>
#include <optional>
#include <thread>
#include <vector>
class CScheduler;
class CNode;
class BanMan;
struct bilingual_str;
/** Default for -whitelistrelay. */
static const bool DEFAULT_WHITELISTRELAY = true;
/** Default for -whitelistforcerelay. */
static const bool DEFAULT_WHITELISTFORCERELAY = false;
/** Time after which to disconnect, after waiting for a ping response (or inactivity). */
static const int TIMEOUT_INTERVAL = 20 * 60;
/** Run the feeler connection loop once every 2 minutes. **/
static constexpr auto FEELER_INTERVAL = 2min;
/** Run the extra block-relay-only connection loop once every 5 minutes. **/
static constexpr auto EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL = 5min;
/** Maximum length of incoming protocol messages (no message over 4 MB is currently acceptable). */
static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 4 * 1000 * 1000;
/** Maximum length of the user agent string in `version` message */
static const unsigned int MAX_SUBVERSION_LENGTH = 256;
/** Maximum number of automatic outgoing nodes over which we'll relay everything (blocks, tx, addrs, etc) */
static const int MAX_OUTBOUND_FULL_RELAY_CONNECTIONS = 8;
/** Maximum number of addnode outgoing nodes */
static const int MAX_ADDNODE_CONNECTIONS = 8;
/** Maximum number of block-relay-only outgoing connections */
static const int MAX_BLOCK_RELAY_ONLY_CONNECTIONS = 2;
/** Maximum number of feeler connections */
static const int MAX_FEELER_CONNECTIONS = 1;
/** -listen default */
static const bool DEFAULT_LISTEN = true;
/** The maximum number of peer connections to maintain. */
static const unsigned int DEFAULT_MAX_PEER_CONNECTIONS = 125;
/** The default for -maxuploadtarget. 0 = Unlimited */
static constexpr uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
/** Default for blocks only*/
static const bool DEFAULT_BLOCKSONLY = false;
/** -peertimeout default */
static const int64_t DEFAULT_PEER_CONNECT_TIMEOUT = 60;
/** Number of file descriptors required for message capture **/
static const int NUM_FDS_MESSAGE_CAPTURE = 1;
static constexpr bool DEFAULT_FORCEDNSSEED{false};
static constexpr bool DEFAULT_DNSSEED{true};
static constexpr bool DEFAULT_FIXEDSEEDS{true};
static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
static const size_t DEFAULT_MAXSENDBUFFER = 1 * 1000;
typedef int64_t NodeId;
struct AddedNodeInfo
{
std::string strAddedNode;
CService resolvedAddress;
bool fConnected;
bool fInbound;
};
class CNodeStats;
class CClientUIInterface;
struct CSerializedNetMsg
{
CSerializedNetMsg() = default;
CSerializedNetMsg(CSerializedNetMsg&&) = default;
CSerializedNetMsg& operator=(CSerializedNetMsg&&) = default;
// No copying, only moves.
CSerializedNetMsg(const CSerializedNetMsg& msg) = delete;
CSerializedNetMsg& operator=(const CSerializedNetMsg&) = delete;
std::vector<unsigned char> data;
std::string m_type;
};
/** Different types of connections to a peer. This enum encapsulates the
* information we have available at the time of opening or accepting the
* connection. Aside from INBOUND, all types are initiated by us.
*
* If adding or removing types, please update CONNECTION_TYPE_DOC in
* src/rpc/net.cpp and src/qt/rpcconsole.cpp, as well as the descriptions in
* src/qt/guiutil.cpp and src/bitcoin-cli.cpp::NetinfoRequestHandler. */
enum class ConnectionType {
/**
* Inbound connections are those initiated by a peer. This is the only
* property we know at the time of connection, until P2P messages are
* exchanged.
*/
INBOUND,
/**
* These are the default connections that we use to connect with the
* network. There is no restriction on what is relayed; by default we relay
* blocks, addresses & transactions. We automatically attempt to open
* MAX_OUTBOUND_FULL_RELAY_CONNECTIONS using addresses from our AddrMan.
*/
OUTBOUND_FULL_RELAY,
/**
* We open manual connections to addresses that users explicitly requested
* via the addnode RPC or the -addnode/-connect configuration options. Even if a
* manual connection is misbehaving, we do not automatically disconnect or
* add it to our discouragement filter.
*/
MANUAL,
/**
* Feeler connections are short-lived connections made to check that a node
* is alive. They can be useful for:
* - test-before-evict: if one of the peers is considered for eviction from
* our AddrMan because another peer is mapped to the same slot in the tried table,
* evict only if this longer-known peer is offline.
* - move node addresses from New to Tried table, so that we have more
* connectable addresses in our AddrMan.
* Note that in the literature ("Eclipse Attacks on Bitcoin’s Peer-to-Peer Network")
* only the latter feature is referred to as "feeler connections",
* although in our codebase feeler connections encompass test-before-evict as well.
* We make these connections approximately every FEELER_INTERVAL:
* first we resolve previously found collisions if they exist (test-before-evict),
* otherwise we connect to a node from the new table.
*/
FEELER,
/**
* We use block-relay-only connections to help prevent against partition
* attacks. By not relaying transactions or addresses, these connections
* are harder to detect by a third party, thus helping obfuscate the
* network topology. We automatically attempt to open
* MAX_BLOCK_RELAY_ONLY_ANCHORS using addresses from our anchors.dat. Then
* addresses from our AddrMan if MAX_BLOCK_RELAY_ONLY_CONNECTIONS
* isn't reached yet.
*/
BLOCK_RELAY,
/**
* AddrFetch connections are short lived connections used to solicit
* addresses from peers. These are initiated to addresses submitted via the
* -seednode command line argument, or under certain conditions when the
* AddrMan is empty.
*/
ADDR_FETCH,
};
/** Convert ConnectionType enum to a string value */
std::string ConnectionTypeAsString(ConnectionType conn_type);
void Discover();
uint16_t GetListenPort();
enum
{
LOCAL_NONE, // unknown
LOCAL_IF, // address a local interface listens on
LOCAL_BIND, // address explicit bound to
LOCAL_MAPPED, // address reported by UPnP or NAT-PMP
LOCAL_MANUAL, // address explicitly specified (-externalip=)
LOCAL_MAX
};
bool IsPeerAddrLocalGood(CNode *pnode);
/** Returns a local address that we should advertise to this peer */
std::optional<CAddress> GetLocalAddrForPeer(CNode *pnode);
/**
* Mark a network as reachable or unreachable (no automatic connects to it)
* @note Networks are reachable by default
*/
void SetReachable(enum Network net, bool reachable);
/** @returns true if the network is reachable, false otherwise */
bool IsReachable(enum Network net);
/** @returns true if the address is in a reachable network, false otherwise */
bool IsReachable(const CNetAddr& addr);
bool AddLocal(const CService& addr, int nScore = LOCAL_NONE);
bool AddLocal(const CNetAddr& addr, int nScore = LOCAL_NONE);
void RemoveLocal(const CService& addr);
bool SeenLocal(const CService& addr);
bool IsLocal(const CService& addr);
bool GetLocal(CService &addr, const CNetAddr *paddrPeer = nullptr);
CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices);
extern bool fDiscover;
extern bool fListen;
/** Subversion as sent to the P2P network in `version` messages */
extern std::string strSubVersion;
struct LocalServiceInfo {
int nScore;
uint16_t nPort;
};
extern RecursiveMutex cs_mapLocalHost;
extern std::map<CNetAddr, LocalServiceInfo> mapLocalHost GUARDED_BY(cs_mapLocalHost);
extern const std::string NET_MESSAGE_COMMAND_OTHER;
typedef std::map<std::string, uint64_t> mapMsgCmdSize; //command, total bytes
class CNodeStats
{
public:
NodeId nodeid;
ServiceFlags nServices;
bool fRelayTxes;
int64_t nLastSend;
int64_t nLastRecv;
int64_t nLastTXTime;
int64_t nLastBlockTime;
int64_t nTimeConnected;
int64_t nTimeOffset;
std::string m_addr_name;
int nVersion;
std::string cleanSubVer;
bool fInbound;
bool m_bip152_highbandwidth_to;
bool m_bip152_highbandwidth_from;
int m_starting_height;
uint64_t nSendBytes;
mapMsgCmdSize mapSendBytesPerMsgCmd;
uint64_t nRecvBytes;
mapMsgCmdSize mapRecvBytesPerMsgCmd;
NetPermissionFlags m_permissionFlags;
std::chrono::microseconds m_last_ping_time;
std::chrono::microseconds m_min_ping_time;
CAmount minFeeFilter;
// Our address, as reported by the peer
std::string addrLocal;
// Address of this peer
CAddress addr;
// Bind address of our side of the connection
CAddress addrBind;
// Network the peer connected through
Network m_network;
uint32_t m_mapped_as;
ConnectionType m_conn_type;
};
/** Transport protocol agnostic message container.
* Ideally it should only contain receive time, payload,
* command and size.
*/
class CNetMessage {
public:
CDataStream m_recv; //!< received message data
std::chrono::microseconds m_time{0}; //!< time of message receipt
uint32_t m_message_size{0}; //!< size of the payload
uint32_t m_raw_message_size{0}; //!< used wire size of the message (including header/checksum)
std::string m_command;
CNetMessage(CDataStream&& recv_in) : m_recv(std::move(recv_in)) {}
void SetVersion(int nVersionIn)
{
m_recv.SetVersion(nVersionIn);
}
};
/** The TransportDeserializer takes care of holding and deserializing the
* network receive buffer. It can deserialize the network buffer into a
* transport protocol agnostic CNetMessage (command & payload)
*/
class TransportDeserializer {
public:
// returns true if the current deserialization is complete
virtual bool Complete() const = 0;
// set the serialization context version
virtual void SetVersion(int version) = 0;
/** read and deserialize data, advances msg_bytes data pointer */
virtual int Read(Span<const uint8_t>& msg_bytes) = 0;
// decomposes a message from the context
virtual std::optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err) = 0;
virtual ~TransportDeserializer() {}
};
class V1TransportDeserializer final : public TransportDeserializer
{
private:
const CChainParams& m_chain_params;
const NodeId m_node_id; // Only for logging
mutable CHash256 hasher;
mutable uint256 data_hash;
bool in_data; // parsing header (false) or data (true)
CDataStream hdrbuf; // partially received header
CMessageHeader hdr; // complete header
CDataStream vRecv; // received message data
unsigned int nHdrPos;
unsigned int nDataPos;
const uint256& GetMessageHash() const;
int readHeader(Span<const uint8_t> msg_bytes);
int readData(Span<const uint8_t> msg_bytes);
void Reset() {
vRecv.clear();
hdrbuf.clear();
hdrbuf.resize(24);
in_data = false;
nHdrPos = 0;
nDataPos = 0;
data_hash.SetNull();
hasher.Reset();
}
public:
V1TransportDeserializer(const CChainParams& chain_params, const NodeId node_id, int nTypeIn, int nVersionIn)
: m_chain_params(chain_params),
m_node_id(node_id),
hdrbuf(nTypeIn, nVersionIn),
vRecv(nTypeIn, nVersionIn)
{
Reset();
}
bool Complete() const override
{
if (!in_data)
return false;
return (hdr.nMessageSize == nDataPos);
}
void SetVersion(int nVersionIn) override
{
hdrbuf.SetVersion(nVersionIn);
vRecv.SetVersion(nVersionIn);
}
int Read(Span<const uint8_t>& msg_bytes) override
{
int ret = in_data ? readData(msg_bytes) : readHeader(msg_bytes);
if (ret < 0) {
Reset();
} else {
msg_bytes = msg_bytes.subspan(ret);
}
return ret;
}
std::optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err_raw_size) override;
};
/** The TransportSerializer prepares messages for the network transport
*/
class TransportSerializer {
public:
// prepare message for transport (header construction, error-correction computation, payload encryption, etc.)
virtual void prepareForTransport(CSerializedNetMsg& msg, std::vector<unsigned char>& header) = 0;
virtual ~TransportSerializer() {}
};
class V1TransportSerializer : public TransportSerializer {
public:
void prepareForTransport(CSerializedNetMsg& msg, std::vector<unsigned char>& header) override;
};
/** Information about a peer */
class CNode
{
friend class CConnman;
friend struct ConnmanTestMsg;
public:
std::unique_ptr<TransportDeserializer> m_deserializer;
std::unique_ptr<TransportSerializer> m_serializer;
NetPermissionFlags m_permissionFlags{NetPermissionFlags::None};
std::atomic<ServiceFlags> nServices{NODE_NONE};
SOCKET hSocket GUARDED_BY(cs_hSocket);
/** Total size of all vSendMsg entries */
size_t nSendSize GUARDED_BY(cs_vSend){0};
/** Offset inside the first vSendMsg already sent */
size_t nSendOffset GUARDED_BY(cs_vSend){0};
uint64_t nSendBytes GUARDED_BY(cs_vSend){0};
std::deque<std::vector<unsigned char>> vSendMsg GUARDED_BY(cs_vSend);
Mutex cs_vSend;
Mutex cs_hSocket;
Mutex cs_vRecv;
RecursiveMutex cs_vProcessMsg;
std::list<CNetMessage> vProcessMsg GUARDED_BY(cs_vProcessMsg);
size_t nProcessQueueSize{0};
RecursiveMutex cs_sendProcessing;
uint64_t nRecvBytes GUARDED_BY(cs_vRecv){0};
std::atomic<int64_t> nLastSend{0};
std::atomic<int64_t> nLastRecv{0};
//! Unix epoch time at peer connection, in seconds.
const int64_t nTimeConnected;
std::atomic<int64_t> nTimeOffset{0};
// Address of this peer
const CAddress addr;
// Bind address of our side of the connection
const CAddress addrBind;
const std::string m_addr_name;
//! Whether this peer is an inbound onion, i.e. connected via our Tor onion service.
const bool m_inbound_onion;
std::atomic<int> nVersion{0};
RecursiveMutex cs_SubVer;
/**
* cleanSubVer is a sanitized string of the user agent byte array we read
* from the wire. This cleaned string can safely be logged or displayed.
*/
std::string cleanSubVer GUARDED_BY(cs_SubVer){};
bool m_prefer_evict{false}; // This peer is preferred for eviction.
bool HasPermission(NetPermissionFlags permission) const {
return NetPermissions::HasFlag(m_permissionFlags, permission);
}
bool fClient{false}; // set by version message
bool m_limited_node{false}; //after BIP159, set by version message
/** fSuccessfullyConnected is set to true on receiving VERACK from the peer. */
std::atomic_bool fSuccessfullyConnected{false};
// Setting fDisconnect to true will cause the node to be disconnected the
// next time DisconnectNodes() runs
std::atomic_bool fDisconnect{false};
CSemaphoreGrant grantOutbound;
std::atomic<int> nRefCount{0};
const uint64_t nKeyedNetGroup;
std::atomic_bool fPauseRecv{false};
std::atomic_bool fPauseSend{false};
bool IsOutboundOrBlockRelayConn() const {
switch (m_conn_type) {
case ConnectionType::OUTBOUND_FULL_RELAY:
case ConnectionType::BLOCK_RELAY:
return true;
case ConnectionType::INBOUND:
case ConnectionType::MANUAL:
case ConnectionType::ADDR_FETCH:
case ConnectionType::FEELER:
return false;
} // no default case, so the compiler can warn about missing cases
assert(false);
}
bool IsFullOutboundConn() const {
return m_conn_type == ConnectionType::OUTBOUND_FULL_RELAY;
}
bool IsManualConn() const {
return m_conn_type == ConnectionType::MANUAL;
}
bool IsBlockOnlyConn() const {
return m_conn_type == ConnectionType::BLOCK_RELAY;
}
bool IsFeelerConn() const {
return m_conn_type == ConnectionType::FEELER;
}
bool IsAddrFetchConn() const {
return m_conn_type == ConnectionType::ADDR_FETCH;
}
bool IsInboundConn() const {
return m_conn_type == ConnectionType::INBOUND;
}
bool ExpectServicesFromConn() const {
switch (m_conn_type) {
case ConnectionType::INBOUND:
case ConnectionType::MANUAL:
case ConnectionType::FEELER:
return false;
case ConnectionType::OUTBOUND_FULL_RELAY:
case ConnectionType::BLOCK_RELAY:
case ConnectionType::ADDR_FETCH:
return true;
} // no default case, so the compiler can warn about missing cases
assert(false);
}
/**
* Get network the peer connected through.
*
* Returns Network::NET_ONION for *inbound* onion connections,
* and CNetAddr::GetNetClass() otherwise. The latter cannot be used directly
* because it doesn't detect the former, and it's not the responsibility of
* the CNetAddr class to know the actual network a peer is connected through.
*
* @return network the peer connected through.
*/
Network ConnectedThroughNetwork() const;
// 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};
struct TxRelay {
mutable RecursiveMutex cs_filter;
// We use fRelayTxes for two purposes -
// a) it allows us to not relay tx invs before receiving the peer's version message
// b) the peer may tell us in its version message that we should not relay tx invs
// unless it loads a bloom filter.
bool fRelayTxes GUARDED_BY(cs_filter){false};
std::unique_ptr<CBloomFilter> pfilter PT_GUARDED_BY(cs_filter) GUARDED_BY(cs_filter){nullptr};
mutable RecursiveMutex cs_tx_inventory;
CRollingBloomFilter filterInventoryKnown GUARDED_BY(cs_tx_inventory){50000, 0.000001};
// Set of transaction ids we still have to announce.
// They are sorted by the mempool before relay, so the order is not important.
std::set<uint256> setInventoryTxToSend;
// Used for BIP35 mempool sending
bool fSendMempool GUARDED_BY(cs_tx_inventory){false};
// Last time a "MEMPOOL" request was serviced.
std::atomic<std::chrono::seconds> m_last_mempool_req{0s};
std::chrono::microseconds nNextInvSend{0};
/** Minimum fee rate with which to filter inv's to this node */
std::atomic<CAmount> minFeeFilter{0};
CAmount lastSentFeeFilter{0};
std::chrono::microseconds m_next_send_feefilter{0};
};
// m_tx_relay == nullptr if we're not relaying transactions with this peer
std::unique_ptr<TxRelay> m_tx_relay;
/** UNIX epoch time of the last block received from this peer that we had
* not yet seen (e.g. not already received from another peer), that passed
* preliminary validity checks and was saved to disk, even if we don't
* connect the block or it eventually fails connection. Used as an inbound
* peer eviction criterium in CConnman::AttemptToEvictConnection. */
std::atomic<int64_t> nLastBlockTime{0};
/** UNIX epoch time of the last transaction received from this peer that we
* had not yet seen (e.g. not already received from another peer) and that
* was accepted into our mempool. Used as an inbound peer eviction criterium
* in CConnman::AttemptToEvictConnection. */
std::atomic<int64_t> nLastTXTime{0};
/** Last measured round-trip time. Used only for RPC/GUI stats/debugging.*/
std::atomic<std::chrono::microseconds> m_last_ping_time{0us};
/** Lowest measured round-trip time. Used as an inbound peer eviction
* criterium in CConnman::AttemptToEvictConnection. */
std::atomic<std::chrono::microseconds> m_min_ping_time{std::chrono::microseconds::max()};
CNode(NodeId id, ServiceFlags nLocalServicesIn, SOCKET hSocketIn, const CAddress& addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const CAddress& addrBindIn, const std::string& addrNameIn, ConnectionType conn_type_in, bool inbound_onion);
~CNode();
CNode(const CNode&) = delete;
CNode& operator=(const CNode&) = delete;
NodeId GetId() const {
return id;
}
uint64_t GetLocalNonce() const {
return nLocalHostNonce;
}
int GetRefCount() const
{
assert(nRefCount >= 0);
return nRefCount;
}
/**
* Receive bytes from the buffer and deserialize them into messages.
*
* @param[in] msg_bytes The raw data
* @param[out] complete Set True if at least one message has been
* deserialized and is ready to be processed
* @return True if the peer should stay connected,
* False if the peer should be disconnected from.
*/
bool ReceiveMsgBytes(Span<const uint8_t> msg_bytes, bool& complete);
void SetCommonVersion(int greatest_common_version)
{
Assume(m_greatest_common_version == INIT_PROTO_VERSION);
m_greatest_common_version = greatest_common_version;
}
int GetCommonVersion() const
{
return m_greatest_common_version;
}
CService GetAddrLocal() const;
//! May not be called more than once
void SetAddrLocal(const CService& addrLocalIn);
CNode* AddRef()
{
nRefCount++;
return this;
}
void Release()
{
nRefCount--;
}
void AddKnownTx(const uint256& hash)
{
if (m_tx_relay != nullptr) {
LOCK(m_tx_relay->cs_tx_inventory);
m_tx_relay->filterInventoryKnown.insert(hash);
}
}
void PushTxInventory(const uint256& hash)
{
if (m_tx_relay == nullptr) return;
LOCK(m_tx_relay->cs_tx_inventory);
if (!m_tx_relay->filterInventoryKnown.contains(hash)) {
m_tx_relay->setInventoryTxToSend.insert(hash);
}
}
void CloseSocketDisconnect();
void CopyStats(CNodeStats& stats, const std::vector<bool>& asmap);
ServiceFlags GetLocalServices() const
{
return nLocalServices;
}
std::string ConnectionTypeAsString() const { return ::ConnectionTypeAsString(m_conn_type); }
/** A ping-pong round trip has completed successfully. Update latest and minimum ping times. */
void PongReceived(std::chrono::microseconds ping_time) {
m_last_ping_time = ping_time;
m_min_ping_time = std::min(m_min_ping_time.load(), ping_time);
}
private:
const NodeId id;
const uint64_t nLocalHostNonce;
const ConnectionType m_conn_type;
std::atomic<int> m_greatest_common_version{INIT_PROTO_VERSION};
//! Services offered to this peer.
//!
//! This is supplied by the parent CConnman during peer connection
//! (CConnman::ConnectNode()) from its attribute of the same name.
//!
//! This is const because there is no protocol defined for renegotiating
//! services initially offered to a peer. The set of local services we
//! offer should not change after initialization.
//!
//! An interesting example of this is NODE_NETWORK and initial block
//! download: a node which starts up from scratch doesn't have any blocks
//! to serve, but still advertises NODE_NETWORK because it will eventually
//! fulfill this role after IBD completes. P2P code is written in such a
//! way that it can gracefully handle peers who don't make good on their
//! service advertisements.
const ServiceFlags nLocalServices;
std::list<CNetMessage> vRecvMsg; // Used only by SocketHandler thread
// Our address, as reported by the peer
CService addrLocal GUARDED_BY(cs_addrLocal);
mutable RecursiveMutex cs_addrLocal;
mapMsgCmdSize mapSendBytesPerMsgCmd GUARDED_BY(cs_vSend);
mapMsgCmdSize mapRecvBytesPerMsgCmd GUARDED_BY(cs_vRecv);
};
/**
* Interface for message handling
*/
class NetEventsInterface
{
public:
/** Initialize a peer (setup state, queue any initial messages) */
virtual void InitializeNode(CNode* pnode) = 0;
/** Handle removal of a peer (clear state) */
virtual void FinalizeNode(const CNode& node) = 0;
/**
* Process protocol messages received from a given node
*
* @param[in] pnode The node which we have received messages from.
* @param[in] interrupt Interrupt condition for processing threads
* @return True if there is more work to be done
*/
virtual bool ProcessMessages(CNode* pnode, std::atomic<bool>& interrupt) = 0;
/**
* Send queued protocol messages to a given node.
*
* @param[in] pnode The node which we are sending messages to.
* @return True if there is more work to be done
*/
virtual bool SendMessages(CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(pnode->cs_sendProcessing) = 0;
protected:
/**
* Protected destructor so that instances can only be deleted by derived classes.
* If that restriction is no longer desired, this should be made public and virtual.
*/
~NetEventsInterface() = default;
};
class CConnman
{
public:
struct Options
{
ServiceFlags nLocalServices = NODE_NONE;
int nMaxConnections = 0;
int m_max_outbound_full_relay = 0;
int m_max_outbound_block_relay = 0;
int nMaxAddnode = 0;
int nMaxFeeler = 0;
CClientUIInterface* uiInterface = nullptr;
NetEventsInterface* m_msgproc = nullptr;
BanMan* m_banman = nullptr;
unsigned int nSendBufferMaxSize = 0;
unsigned int nReceiveFloodSize = 0;
uint64_t nMaxOutboundLimit = 0;
int64_t m_peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
std::vector<std::string> vSeedNodes;
std::vector<NetWhitelistPermissions> vWhitelistedRange;
std::vector<NetWhitebindPermissions> vWhiteBinds;
std::vector<CService> vBinds;
std::vector<CService> onion_binds;
/// True if the user did not specify -bind= or -whitebind= and thus
/// we should bind on `0.0.0.0` (IPv4) and `::` (IPv6).
bool bind_on_any;
bool m_use_addrman_outgoing = true;
std::vector<std::string> m_specified_outgoing;
std::vector<std::string> m_added_nodes;
std::vector<bool> m_asmap;
bool m_i2p_accept_incoming;
};
void Init(const Options& connOptions) {
nLocalServices = connOptions.nLocalServices;
nMaxConnections = connOptions.nMaxConnections;
m_max_outbound_full_relay = std::min(connOptions.m_max_outbound_full_relay, connOptions.nMaxConnections);
m_max_outbound_block_relay = connOptions.m_max_outbound_block_relay;
m_use_addrman_outgoing = connOptions.m_use_addrman_outgoing;
nMaxAddnode = connOptions.nMaxAddnode;
nMaxFeeler = connOptions.nMaxFeeler;
m_max_outbound = m_max_outbound_full_relay + m_max_outbound_block_relay + nMaxFeeler;
m_client_interface = connOptions.uiInterface;
m_banman = connOptions.m_banman;
m_msgproc = connOptions.m_msgproc;
nSendBufferMaxSize = connOptions.nSendBufferMaxSize;
nReceiveFloodSize = connOptions.nReceiveFloodSize;
m_peer_connect_timeout = connOptions.m_peer_connect_timeout;
{
LOCK(cs_totalBytesSent);
nMaxOutboundLimit = connOptions.nMaxOutboundLimit;
}
vWhitelistedRange = connOptions.vWhitelistedRange;
{
LOCK(cs_vAddedNodes);
vAddedNodes = connOptions.m_added_nodes;
}
m_onion_binds = connOptions.onion_binds;
}
CConnman(uint64_t seed0, uint64_t seed1, CAddrMan& addrman, bool network_active = true);
~CConnman();
bool Start(CScheduler& scheduler, const Options& options);
void StopThreads();
void StopNodes();
void Stop()
{
StopThreads();
StopNodes();
};
void Interrupt();
bool GetNetworkActive() const { return fNetworkActive; };
bool GetUseAddrmanOutgoing() const { return m_use_addrman_outgoing; };
void SetNetworkActive(bool active);
void OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant* grantOutbound, const char* strDest, ConnectionType conn_type);
bool CheckIncomingNonce(uint64_t nonce);
bool ForNode(NodeId id, std::function<bool(CNode* pnode)> func);
void PushMessage(CNode* pnode, CSerializedNetMsg&& msg);
using NodeFn = std::function<void(CNode*)>;
void ForEachNode(const NodeFn& func)
{
LOCK(cs_vNodes);
for (auto&& node : vNodes) {
if (NodeFullyConnected(node))
func(node);
}
};
void ForEachNode(const NodeFn& func) const
{
LOCK(cs_vNodes);
for (auto&& node : vNodes) {
if (NodeFullyConnected(node))
func(node);
}
};
// Addrman functions
/**
* Return all or many randomly selected addresses, optionally by network.
*
* @param[in] max_addresses Maximum number of addresses to return (0 = all).
* @param[in] max_pct Maximum percentage of addresses to return (0 = all).
* @param[in] network Select only addresses of this network (nullopt = all).
*/
std::vector<CAddress> GetAddresses(size_t max_addresses, size_t max_pct, std::optional<Network> network) const;
/**
* Cache is used to minimize topology leaks, so it should
* be used for all non-trusted calls, for example, p2p.
* A non-malicious call (from RPC or a peer with addr permission) should
* call the function without a parameter to avoid using the cache.
*/
std::vector<CAddress> GetAddresses(CNode& requestor, size_t max_addresses, size_t max_pct);
// This allows temporarily exceeding m_max_outbound_full_relay, with the goal of finding
// a peer that is better than all our current peers.
void SetTryNewOutboundPeer(bool flag);
bool GetTryNewOutboundPeer() const;
void StartExtraBlockRelayPeers() {
LogPrint(BCLog::NET, "net: enabling extra block-relay-only peers\n");
m_start_extra_block_relay_peers = true;
}
// Return the number of outbound peers we have in excess of our target (eg,
// if we previously called SetTryNewOutboundPeer(true), and have since set
// to false, we may have extra peers that we wish to disconnect). This may
// return a value less than (num_outbound_connections - num_outbound_slots)
// in cases where some outbound connections are not yet fully connected, or
// not yet fully disconnected.
int GetExtraFullOutboundCount() const;
// Count the number of block-relay-only peers we have over our limit.
int GetExtraBlockRelayCount() const;
bool AddNode(const std::string& node);
bool RemoveAddedNode(const std::string& node);
std::vector<AddedNodeInfo> GetAddedNodeInfo() const;
/**
* Attempts to open a connection. Currently only used from tests.
*
* @param[in] address Address of node to try connecting to
* @param[in] conn_type ConnectionType::OUTBOUND or ConnectionType::BLOCK_RELAY
* or ConnectionType::ADDR_FETCH
* @return bool Returns false if there are no available
* slots for this connection:
* - conn_type not a supported ConnectionType
* - Max total outbound connection capacity filled
* - Max connection capacity for type is filled
*/
bool AddConnection(const std::string& address, ConnectionType conn_type);
size_t GetNodeCount(ConnectionDirection) const;
void GetNodeStats(std::vector<CNodeStats>& vstats) const;
bool DisconnectNode(const std::string& node);
bool DisconnectNode(const CSubNet& subnet);
bool DisconnectNode(const CNetAddr& addr);
bool DisconnectNode(NodeId id);
//! Used to convey which local services we are offering peers during node
//! connection.
//!
//! The data returned by this is used in CNode construction,
//! which is used to advertise which services we are offering
//! that peer during `net_processing.cpp:PushNodeVersion()`.
ServiceFlags GetLocalServices() const;
uint64_t GetMaxOutboundTarget() const;
std::chrono::seconds GetMaxOutboundTimeframe() const;
//! check if the outbound target is reached
//! if param historicalBlockServingLimit is set true, the function will
//! response true if the limit for serving historical blocks has been reached
bool OutboundTargetReached(bool historicalBlockServingLimit) const;
//! response the bytes left in the current max outbound cycle
//! in case of no limit, it will always response 0
uint64_t GetOutboundTargetBytesLeft() const;
//! returns the time left in the current max outbound cycle
//! in case of no limit, it will always return 0
std::chrono::seconds GetMaxOutboundTimeLeftInCycle() const;
uint64_t GetTotalBytesRecv() const;
uint64_t GetTotalBytesSent() const;
/** Get a unique deterministic randomizer. */
CSipHasher GetDeterministicRandomizer(uint64_t id) const;
unsigned int GetReceiveFloodSize() const;
void WakeMessageHandler();
/** Attempts to obfuscate tx time through exponentially distributed emitting.
Works assuming that a single interval is used.
Variable intervals will result in privacy decrease.
*/
std::chrono::microseconds PoissonNextSendInbound(std::chrono::microseconds now, std::chrono::seconds average_interval);
/** Return true if we should disconnect the peer for failing an inactivity check. */
bool ShouldRunInactivityChecks(const CNode& node, std::optional<int64_t> now=std::nullopt) const;
private:
struct ListenSocket {
public:
SOCKET socket;
inline void AddSocketPermissionFlags(NetPermissionFlags& flags) const { NetPermissions::AddFlag(flags, m_permissions); }
ListenSocket(SOCKET socket_, NetPermissionFlags permissions_) : socket(socket_), m_permissions(permissions_) {}
private:
NetPermissionFlags m_permissions;
};
bool BindListenPort(const CService& bindAddr, bilingual_str& strError, NetPermissionFlags permissions);
bool Bind(const CService& addr, unsigned int flags, NetPermissionFlags permissions);
bool InitBinds(const Options& options);
void ThreadOpenAddedConnections();
void AddAddrFetch(const std::string& strDest);
void ProcessAddrFetch();
void ThreadOpenConnections(std::vector<std::string> connect);
void ThreadMessageHandler();
void ThreadI2PAcceptIncoming();
void AcceptConnection(const ListenSocket& hListenSocket);
/**
* Create a `CNode` object from a socket that has just been accepted and add the node to
* the `vNodes` member.
* @param[in] hSocket Connected socket to communicate with the peer.
* @param[in] permissionFlags The peer's permissions.
* @param[in] addr_bind The address and port at our side of the connection.
* @param[in] addr The address and port at the peer's side of the connection.
*/
void CreateNodeFromAcceptedSocket(SOCKET hSocket,
NetPermissionFlags permissionFlags,
const CAddress& addr_bind,
const CAddress& addr);
void DisconnectNodes();
void NotifyNumConnectionsChanged();
/** Return true if the peer is inactive and should be disconnected. */
bool InactivityCheck(const CNode& node) const;
bool GenerateSelectSet(std::set<SOCKET> &recv_set, std::set<SOCKET> &send_set, std::set<SOCKET> &error_set);
void SocketEvents(std::set<SOCKET> &recv_set, std::set<SOCKET> &send_set, std::set<SOCKET> &error_set);
void SocketHandler();
void ThreadSocketHandler();
void ThreadDNSAddressSeed();
uint64_t CalculateKeyedNetGroup(const CAddress& ad) const;
CNode* FindNode(const CNetAddr& ip);
CNode* FindNode(const CSubNet& subNet);
CNode* FindNode(const std::string& addrName);
CNode* FindNode(const CService& addr);
/**
* Determine whether we're already connected to a given address, in order to
* avoid initiating duplicate connections.
*/
bool AlreadyConnectedToAddress(const CAddress& addr);
bool AttemptToEvictConnection();
CNode* ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure, ConnectionType conn_type);
void AddWhitelistPermissionFlags(NetPermissionFlags& flags, const CNetAddr &addr) const;
void DeleteNode(CNode* pnode);
NodeId GetNewNodeId();
size_t SocketSendData(CNode& node) const EXCLUSIVE_LOCKS_REQUIRED(node.cs_vSend);
void DumpAddresses();
// Network stats
void RecordBytesRecv(uint64_t bytes);
void RecordBytesSent(uint64_t bytes);
/**
* Return vector of current BLOCK_RELAY peers.
*/
std::vector<CAddress> GetCurrentBlockRelayOnlyConns() const;
// Whether the node should be passed out in ForEach* callbacks
static bool NodeFullyConnected(const CNode* pnode);
// Network usage totals
mutable RecursiveMutex cs_totalBytesRecv;
mutable RecursiveMutex cs_totalBytesSent;
uint64_t nTotalBytesRecv GUARDED_BY(cs_totalBytesRecv) {0};
uint64_t nTotalBytesSent GUARDED_BY(cs_totalBytesSent) {0};
// outbound limit & stats
uint64_t nMaxOutboundTotalBytesSentInCycle GUARDED_BY(cs_totalBytesSent) {0};
std::chrono::seconds nMaxOutboundCycleStartTime GUARDED_BY(cs_totalBytesSent) {0};
uint64_t nMaxOutboundLimit GUARDED_BY(cs_totalBytesSent);
// P2P timeout in seconds
int64_t m_peer_connect_timeout;
// Whitelisted ranges. Any node connecting from these is automatically
// whitelisted (as well as those connecting to whitelisted binds).
std::vector<NetWhitelistPermissions> vWhitelistedRange;
unsigned int nSendBufferMaxSize{0};
unsigned int nReceiveFloodSize{0};
std::vector<ListenSocket> vhListenSocket;
std::atomic<bool> fNetworkActive{true};
bool fAddressesInitialized{false};
CAddrMan& addrman;
std::deque<std::string> m_addr_fetches GUARDED_BY(m_addr_fetches_mutex);
RecursiveMutex m_addr_fetches_mutex;
std::vector<std::string> vAddedNodes GUARDED_BY(cs_vAddedNodes);
mutable RecursiveMutex cs_vAddedNodes;
std::vector<CNode*> vNodes GUARDED_BY(cs_vNodes);
std::list<CNode*> vNodesDisconnected;
mutable RecursiveMutex cs_vNodes;
std::atomic<NodeId> nLastNodeId{0};
unsigned int nPrevNodeCount{0};
/**
* Cache responses to addr requests to minimize privacy leak.
* Attack example: scraping addrs in real-time may allow an attacker
* to infer new connections of the victim by detecting new records
* with fresh timestamps (per self-announcement).
*/
struct CachedAddrResponse {
std::vector<CAddress> m_addrs_response_cache;
std::chrono::microseconds m_cache_entry_expiration{0};
};
/**
* Addr responses stored in different caches
* per (network, local socket) prevent cross-network node identification.
* If a node for example is multi-homed under Tor and IPv6,
* a single cache (or no cache at all) would let an attacker
* to easily detect that it is the same node by comparing responses.
* Indexing by local socket prevents leakage when a node has multiple
* listening addresses on the same network.
*
* The used memory equals to 1000 CAddress records (or around 40 bytes) per
* distinct Network (up to 5) we have/had an inbound peer from,
* resulting in at most ~196 KB. Every separate local socket may
* add up to ~196 KB extra.
*/
std::map<uint64_t, CachedAddrResponse> m_addr_response_caches;
/**
* Services this instance offers.
*
* This data is replicated in each CNode instance we create during peer
* connection (in ConnectNode()) under a member also called
* nLocalServices.
*
* This data is not marked const, but after being set it should not
* change. See the note in CNode::nLocalServices documentation.
*
* \sa CNode::nLocalServices
*/
ServiceFlags nLocalServices;
std::unique_ptr<CSemaphore> semOutbound;
std::unique_ptr<CSemaphore> semAddnode;
int nMaxConnections;
// How many full-relay (tx, block, addr) outbound peers we want
int m_max_outbound_full_relay;
// How many block-relay only outbound peers we want
// We do not relay tx or addr messages with these peers
int m_max_outbound_block_relay;
int nMaxAddnode;
int nMaxFeeler;
int m_max_outbound;
bool m_use_addrman_outgoing;
CClientUIInterface* m_client_interface;
NetEventsInterface* m_msgproc;
/** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */
BanMan* m_banman;
/**
* Addresses that were saved during the previous clean shutdown. We'll
* attempt to make block-relay-only connections to them.
*/
std::vector<CAddress> m_anchors;
/** SipHasher seeds for deterministic randomness */
const uint64_t nSeed0, nSeed1;
/** flag for waking the message processor. */
bool fMsgProcWake GUARDED_BY(mutexMsgProc);
std::condition_variable condMsgProc;
Mutex mutexMsgProc;
std::atomic<bool> flagInterruptMsgProc{false};
/**
* This is signaled when network activity should cease.
* A pointer to it is saved in `m_i2p_sam_session`, so make sure that
* the lifetime of `interruptNet` is not shorter than
* the lifetime of `m_i2p_sam_session`.
*/
CThreadInterrupt interruptNet;
/**
* I2P SAM session.
* Used to accept incoming and make outgoing I2P connections.
*/
std::unique_ptr<i2p::sam::Session> m_i2p_sam_session;
std::thread threadDNSAddressSeed;
std::thread threadSocketHandler;
std::thread threadOpenAddedConnections;
std::thread threadOpenConnections;
std::thread threadMessageHandler;
std::thread threadI2PAcceptIncoming;
/** flag for deciding to connect to an extra outbound peer,
* in excess of m_max_outbound_full_relay
* This takes the place of a feeler connection */
std::atomic_bool m_try_another_outbound_peer;
/** flag for initiating extra block-relay-only peer connections.
* this should only be enabled after initial chain sync has occurred,
* as these connections are intended to be short-lived and low-bandwidth.
*/
std::atomic_bool m_start_extra_block_relay_peers{false};
std::atomic<std::chrono::microseconds> m_next_send_inv_to_incoming{0us};
/**
* A vector of -bind=<address>:<port>=onion arguments each of which is
* an address and port that are designated for incoming Tor connections.
*/
std::vector<CService> m_onion_binds;
friend struct CConnmanTest;
friend struct ConnmanTestMsg;
};
/** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now, std::chrono::seconds average_interval);
/** Dump binary message to file, with timestamp */
void CaptureMessage(const CAddress& addr, const std::string& msg_type, const Span<const unsigned char>& data, bool is_incoming);
struct NodeEvictionCandidate
{
NodeId id;
int64_t nTimeConnected;
std::chrono::microseconds m_min_ping_time;
int64_t nLastBlockTime;
int64_t nLastTXTime;
bool fRelevantServices;
bool fRelayTxes;
bool fBloomFilter;
uint64_t nKeyedNetGroup;
bool prefer_evict;
bool m_is_local;
Network m_network;
};
/**
* Select an inbound peer to evict after filtering out (protecting) peers having
* distinct, difficult-to-forge characteristics. The protection logic picks out
* fixed numbers of desirable peers per various criteria, followed by (mostly)
* ratios of desirable or disadvantaged peers. If any eviction candidates
* remain, the selection logic chooses a peer to evict.
*/
[[nodiscard]] std::optional<NodeId> SelectNodeToEvict(std::vector<NodeEvictionCandidate>&& vEvictionCandidates);
/** Protect desirable or disadvantaged inbound peers from eviction by ratio.
*
* This function protects half of the peers which have been connected the
* longest, to replicate the non-eviction implicit behavior and preclude attacks
* that start later.
*
* Half of these protected spots (1/4 of the total) are reserved for the
* following categories of peers, sorted by longest uptime, even if they're not
* longest uptime overall:
*
* - onion peers connected via our tor control service
*
* - localhost peers, as manually configured hidden services not using
* `-bind=addr[:port]=onion` will not be detected as inbound onion connections
*
* - I2P peers
*
* This helps protect these privacy network peers, which tend to be otherwise
* disadvantaged under our eviction criteria for their higher min ping times
* relative to IPv4/IPv6 peers, and favorise the diversity of peer connections.
*/
void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& vEvictionCandidates);
#endif // BITCOIN_NET_H