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bitcoin/src/net.cpp

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <net.h>
#include <addrdb.h>
#include <addrman.h>
#include <banman.h>
#include <clientversion.h>
#include <common/args.h>
#include <compat/compat.h>
#include <consensus/consensus.h>
#include <crypto/sha256.h>
#include <i2p.h>
#include <key.h>
#include <logging.h>
#include <memusage.h>
#include <net_permissions.h>
#include <netaddress.h>
#include <netbase.h>
#include <node/eviction.h>
#include <node/interface_ui.h>
#include <protocol.h>
#include <random.h>
#include <scheduler.h>
#include <util/fs.h>
#include <util/sock.h>
#include <util/strencodings.h>
#include <util/thread.h>
#include <util/threadinterrupt.h>
#include <util/trace.h>
#include <util/translation.h>
#include <util/vector.h>
#ifdef WIN32
#include <string.h>
#endif
#if HAVE_DECL_GETIFADDRS && HAVE_DECL_FREEIFADDRS
#include <ifaddrs.h>
#endif
#include <algorithm>
#include <array>
#include <cstdint>
#include <functional>
#include <optional>
#include <unordered_map>
#include <math.h>
/** Maximum number of block-relay-only anchor connections */
static constexpr size_t MAX_BLOCK_RELAY_ONLY_ANCHORS = 2;
static_assert (MAX_BLOCK_RELAY_ONLY_ANCHORS <= static_cast<size_t>(MAX_BLOCK_RELAY_ONLY_CONNECTIONS), "MAX_BLOCK_RELAY_ONLY_ANCHORS must not exceed MAX_BLOCK_RELAY_ONLY_CONNECTIONS.");
/** Anchor IP address database file name */
const char* const ANCHORS_DATABASE_FILENAME = "anchors.dat";
// How often to dump addresses to peers.dat
static constexpr std::chrono::minutes DUMP_PEERS_INTERVAL{15};
/** Number of DNS seeds to query when the number of connections is low. */
static constexpr int DNSSEEDS_TO_QUERY_AT_ONCE = 3;
/** How long to delay before querying DNS seeds
*
* If we have more than THRESHOLD entries in addrman, then it's likely
* that we got those addresses from having previously connected to the P2P
* network, and that we'll be able to successfully reconnect to the P2P
* network via contacting one of them. So if that's the case, spend a
* little longer trying to connect to known peers before querying the
* DNS seeds.
*/
static constexpr std::chrono::seconds DNSSEEDS_DELAY_FEW_PEERS{11};
static constexpr std::chrono::minutes DNSSEEDS_DELAY_MANY_PEERS{5};
static constexpr int DNSSEEDS_DELAY_PEER_THRESHOLD = 1000; // "many" vs "few" peers
/** The default timeframe for -maxuploadtarget. 1 day. */
static constexpr std::chrono::seconds MAX_UPLOAD_TIMEFRAME{60 * 60 * 24};
// A random time period (0 to 1 seconds) is added to feeler connections to prevent synchronization.
static constexpr auto FEELER_SLEEP_WINDOW{1s};
/** Frequency to attempt extra connections to reachable networks we're not connected to yet **/
static constexpr auto EXTRA_NETWORK_PEER_INTERVAL{5min};
/** Used to pass flags to the Bind() function */
enum BindFlags {
BF_NONE = 0,
BF_REPORT_ERROR = (1U << 0),
/**
* Do not call AddLocal() for our special addresses, e.g., for incoming
* Tor connections, to prevent gossiping them over the network.
*/
BF_DONT_ADVERTISE = (1U << 1),
};
// The set of sockets cannot be modified while waiting
// The sleep time needs to be small to avoid new sockets stalling
static const uint64_t SELECT_TIMEOUT_MILLISECONDS = 50;
const std::string NET_MESSAGE_TYPE_OTHER = "*other*";
static const uint64_t RANDOMIZER_ID_NETGROUP = 0x6c0edd8036ef4036ULL; // SHA256("netgroup")[0:8]
static const uint64_t RANDOMIZER_ID_LOCALHOSTNONCE = 0xd93e69e2bbfa5735ULL; // SHA256("localhostnonce")[0:8]
static const uint64_t RANDOMIZER_ID_ADDRCACHE = 0x1cf2e4ddd306dda9ULL; // SHA256("addrcache")[0:8]
//
// Global state variables
//
bool fDiscover = true;
bool fListen = true;
GlobalMutex g_maplocalhost_mutex;
std::map<CNetAddr, LocalServiceInfo> mapLocalHost GUARDED_BY(g_maplocalhost_mutex);
std::string strSubVersion;
size_t CSerializedNetMsg::GetMemoryUsage() const noexcept
{
// Don't count the dynamic memory used for the m_type string, by assuming it fits in the
// "small string" optimization area (which stores data inside the object itself, up to some
// size; 15 bytes in modern libstdc++).
return sizeof(*this) + memusage::DynamicUsage(data);
}
void CConnman::AddAddrFetch(const std::string& strDest)
{
LOCK(m_addr_fetches_mutex);
m_addr_fetches.push_back(strDest);
}
uint16_t GetListenPort()
{
// If -bind= is provided with ":port" part, use that (first one if multiple are provided).
for (const std::string& bind_arg : gArgs.GetArgs("-bind")) {
constexpr uint16_t dummy_port = 0;
const std::optional<CService> bind_addr{Lookup(bind_arg, dummy_port, /*fAllowLookup=*/false)};
if (bind_addr.has_value() && bind_addr->GetPort() != dummy_port) return bind_addr->GetPort();
}
// Otherwise, if -whitebind= without NetPermissionFlags::NoBan is provided, use that
// (-whitebind= is required to have ":port").
for (const std::string& whitebind_arg : gArgs.GetArgs("-whitebind")) {
NetWhitebindPermissions whitebind;
bilingual_str error;
if (NetWhitebindPermissions::TryParse(whitebind_arg, whitebind, error)) {
if (!NetPermissions::HasFlag(whitebind.m_flags, NetPermissionFlags::NoBan)) {
return whitebind.m_service.GetPort();
}
}
}
// Otherwise, if -port= is provided, use that. Otherwise use the default port.
return static_cast<uint16_t>(gArgs.GetIntArg("-port", Params().GetDefaultPort()));
}
// Determine the "best" local address for a particular peer.
[[nodiscard]] static std::optional<CService> GetLocal(const CNode& peer)
{
if (!fListen) return std::nullopt;
std::optional<CService> addr;
int nBestScore = -1;
int nBestReachability = -1;
{
LOCK(g_maplocalhost_mutex);
for (const auto& [local_addr, local_service_info] : mapLocalHost) {
// For privacy reasons, don't advertise our privacy-network address
// to other networks and don't advertise our other-network address
// to privacy networks.
if (local_addr.GetNetwork() != peer.ConnectedThroughNetwork()
&& (local_addr.IsPrivacyNet() || peer.IsConnectedThroughPrivacyNet())) {
continue;
}
const int nScore{local_service_info.nScore};
const int nReachability{local_addr.GetReachabilityFrom(peer.addr)};
if (nReachability > nBestReachability || (nReachability == nBestReachability && nScore > nBestScore)) {
addr.emplace(CService{local_addr, local_service_info.nPort});
nBestReachability = nReachability;
nBestScore = nScore;
}
}
}
return addr;
}
//! Convert the serialized seeds into usable address objects.
static std::vector<CAddress> ConvertSeeds(const std::vector<uint8_t> &vSeedsIn)
{
// It'll only connect to one or two seed nodes because once it connects,
// it'll get a pile of addresses with newer timestamps.
// Seed nodes are given a random 'last seen time' of between one and two
// weeks ago.
const auto one_week{7 * 24h};
std::vector<CAddress> vSeedsOut;
FastRandomContext rng;
DataStream underlying_stream{vSeedsIn};
ParamsStream s{CAddress::V2_NETWORK, underlying_stream};
while (!s.eof()) {
CService endpoint;
s >> endpoint;
CAddress addr{endpoint, SeedsServiceFlags()};
addr.nTime = rng.rand_uniform_delay(Now<NodeSeconds>() - one_week, -one_week);
LogPrint(BCLog::NET, "Added hardcoded seed: %s\n", addr.ToStringAddrPort());
vSeedsOut.push_back(addr);
}
return vSeedsOut;
}
// Determine the "best" local address for a particular peer.
// If none, return the unroutable 0.0.0.0 but filled in with
// the normal parameters, since the IP may be changed to a useful
// one by discovery.
CService GetLocalAddress(const CNode& peer)
{
return GetLocal(peer).value_or(CService{CNetAddr(), GetListenPort()});
}
static int GetnScore(const CService& addr)
{
LOCK(g_maplocalhost_mutex);
const auto it = mapLocalHost.find(addr);
return (it != mapLocalHost.end()) ? it->second.nScore : 0;
}
// Is our peer's addrLocal potentially useful as an external IP source?
[[nodiscard]] static bool IsPeerAddrLocalGood(CNode *pnode)
{
CService addrLocal = pnode->GetAddrLocal();
return fDiscover && pnode->addr.IsRoutable() && addrLocal.IsRoutable() &&
g_reachable_nets.Contains(addrLocal);
}
std::optional<CService> GetLocalAddrForPeer(CNode& node)
{
CService addrLocal{GetLocalAddress(node)};
// If discovery is enabled, sometimes give our peer the address it
// tells us that it sees us as in case it has a better idea of our
// address than we do.
FastRandomContext rng;
if (IsPeerAddrLocalGood(&node) && (!addrLocal.IsRoutable() ||
rng.randbits((GetnScore(addrLocal) > LOCAL_MANUAL) ? 3 : 1) == 0))
{
if (node.IsInboundConn()) {
// For inbound connections, assume both the address and the port
// as seen from the peer.
addrLocal = CService{node.GetAddrLocal()};
} else {
// For outbound connections, assume just the address as seen from
// the peer and leave the port in `addrLocal` as returned by
// `GetLocalAddress()` above. The peer has no way to observe our
// listening port when we have initiated the connection.
addrLocal.SetIP(node.GetAddrLocal());
}
}
if (addrLocal.IsRoutable()) {
LogPrint(BCLog::NET, "Advertising address %s to peer=%d\n", addrLocal.ToStringAddrPort(), node.GetId());
return addrLocal;
}
// Address is unroutable. Don't advertise.
return std::nullopt;
}
// learn a new local address
bool AddLocal(const CService& addr_, int nScore)
{
CService addr{MaybeFlipIPv6toCJDNS(addr_)};
if (!addr.IsRoutable())
return false;
if (!fDiscover && nScore < LOCAL_MANUAL)
return false;
if (!g_reachable_nets.Contains(addr))
return false;
LogPrintf("AddLocal(%s,%i)\n", addr.ToStringAddrPort(), nScore);
{
LOCK(g_maplocalhost_mutex);
const auto [it, is_newly_added] = mapLocalHost.emplace(addr, LocalServiceInfo());
LocalServiceInfo &info = it->second;
if (is_newly_added || nScore >= info.nScore) {
info.nScore = nScore + (is_newly_added ? 0 : 1);
info.nPort = addr.GetPort();
}
}
return true;
}
bool AddLocal(const CNetAddr &addr, int nScore)
{
return AddLocal(CService(addr, GetListenPort()), nScore);
}
void RemoveLocal(const CService& addr)
{
LOCK(g_maplocalhost_mutex);
LogPrintf("RemoveLocal(%s)\n", addr.ToStringAddrPort());
mapLocalHost.erase(addr);
}
/** vote for a local address */
bool SeenLocal(const CService& addr)
{
LOCK(g_maplocalhost_mutex);
const auto it = mapLocalHost.find(addr);
if (it == mapLocalHost.end()) return false;
++it->second.nScore;
return true;
}
/** check whether a given address is potentially local */
bool IsLocal(const CService& addr)
{
LOCK(g_maplocalhost_mutex);
return mapLocalHost.count(addr) > 0;
}
CNode* CConnman::FindNode(const CNetAddr& ip)
{
LOCK(m_nodes_mutex);
for (CNode* pnode : m_nodes) {
if (static_cast<CNetAddr>(pnode->addr) == ip) {
return pnode;
}
}
return nullptr;
}
CNode* CConnman::FindNode(const std::string& addrName)
{
LOCK(m_nodes_mutex);
for (CNode* pnode : m_nodes) {
if (pnode->m_addr_name == addrName) {
return pnode;
}
}
return nullptr;
}
CNode* CConnman::FindNode(const CService& addr)
{
LOCK(m_nodes_mutex);
for (CNode* pnode : m_nodes) {
if (static_cast<CService>(pnode->addr) == addr) {
return pnode;
}
}
return nullptr;
}
bool CConnman::AlreadyConnectedToAddress(const CAddress& addr)
{
return FindNode(static_cast<CNetAddr>(addr)) || FindNode(addr.ToStringAddrPort());
}
bool CConnman::CheckIncomingNonce(uint64_t nonce)
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (!pnode->fSuccessfullyConnected && !pnode->IsInboundConn() && pnode->GetLocalNonce() == nonce)
return false;
}
return true;
}
/** Get the bind address for a socket as CAddress */
static CAddress GetBindAddress(const Sock& sock)
{
CAddress addr_bind;
struct sockaddr_storage sockaddr_bind;
socklen_t sockaddr_bind_len = sizeof(sockaddr_bind);
if (!sock.GetSockName((struct sockaddr*)&sockaddr_bind, &sockaddr_bind_len)) {
addr_bind.SetSockAddr((const struct sockaddr*)&sockaddr_bind);
} else {
LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "getsockname failed\n");
}
return addr_bind;
}
CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure, ConnectionType conn_type, bool use_v2transport)
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
assert(conn_type != ConnectionType::INBOUND);
if (pszDest == nullptr) {
if (IsLocal(addrConnect))
return nullptr;
// Look for an existing connection
CNode* pnode = FindNode(static_cast<CService>(addrConnect));
if (pnode)
{
LogPrintf("Failed to open new connection, already connected\n");
return nullptr;
}
}
LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "trying %s connection %s lastseen=%.1fhrs\n",
use_v2transport ? "v2" : "v1",
pszDest ? pszDest : addrConnect.ToStringAddrPort(),
Ticks<HoursDouble>(pszDest ? 0h : Now<NodeSeconds>() - addrConnect.nTime));
// Resolve
const uint16_t default_port{pszDest != nullptr ? GetDefaultPort(pszDest) :
m_params.GetDefaultPort()};
// Collection of addresses to try to connect to: either all dns resolved addresses if a domain name (pszDest) is provided, or addrConnect otherwise.
std::vector<CAddress> connect_to{};
if (pszDest) {
std::vector<CService> resolved{Lookup(pszDest, default_port, fNameLookup && !HaveNameProxy(), 256)};
if (!resolved.empty()) {
Shuffle(resolved.begin(), resolved.end(), FastRandomContext());
// If the connection is made by name, it can be the case that the name resolves to more than one address.
// We don't want to connect any more of them if we are already connected to one
for (const auto& r : resolved) {
addrConnect = CAddress{MaybeFlipIPv6toCJDNS(r), NODE_NONE};
if (!addrConnect.IsValid()) {
LogPrint(BCLog::NET, "Resolver returned invalid address %s for %s\n", addrConnect.ToStringAddrPort(), pszDest);
return nullptr;
}
// It is possible that we already have a connection to the IP/port pszDest resolved to.
// In that case, drop the connection that was just created.
LOCK(m_nodes_mutex);
CNode* pnode = FindNode(static_cast<CService>(addrConnect));
if (pnode) {
LogPrintf("Not opening a connection to %s, already connected to %s\n", pszDest, addrConnect.ToStringAddrPort());
return nullptr;
}
// Add the address to the resolved addresses vector so we can try to connect to it later on
connect_to.push_back(addrConnect);
}
} else {
// For resolution via proxy
connect_to.push_back(addrConnect);
}
} else {
// Connect via addrConnect directly
connect_to.push_back(addrConnect);
}
// Connect
std::unique_ptr<Sock> sock;
Proxy proxy;
CAddress addr_bind;
assert(!addr_bind.IsValid());
std::unique_ptr<i2p::sam::Session> i2p_transient_session;
for (auto& target_addr: connect_to) {
if (target_addr.IsValid()) {
const bool use_proxy{GetProxy(target_addr.GetNetwork(), proxy)};
bool proxyConnectionFailed = false;
if (target_addr.IsI2P() && use_proxy) {
i2p::Connection conn;
bool connected{false};
if (m_i2p_sam_session) {
connected = m_i2p_sam_session->Connect(target_addr, conn, proxyConnectionFailed);
} else {
{
LOCK(m_unused_i2p_sessions_mutex);
if (m_unused_i2p_sessions.empty()) {
i2p_transient_session =
std::make_unique<i2p::sam::Session>(proxy, &interruptNet);
} else {
i2p_transient_session.swap(m_unused_i2p_sessions.front());
m_unused_i2p_sessions.pop();
}
}
connected = i2p_transient_session->Connect(target_addr, conn, proxyConnectionFailed);
if (!connected) {
LOCK(m_unused_i2p_sessions_mutex);
if (m_unused_i2p_sessions.size() < MAX_UNUSED_I2P_SESSIONS_SIZE) {
m_unused_i2p_sessions.emplace(i2p_transient_session.release());
}
}
}
if (connected) {
sock = std::move(conn.sock);
addr_bind = CAddress{conn.me, NODE_NONE};
}
} else if (use_proxy) {
LogPrintLevel(BCLog::PROXY, BCLog::Level::Debug, "Using proxy: %s to connect to %s\n", proxy.ToString(), target_addr.ToStringAddrPort());
sock = ConnectThroughProxy(proxy, target_addr.ToStringAddr(), target_addr.GetPort(), proxyConnectionFailed);
} else {
// no proxy needed (none set for target network)
sock = ConnectDirectly(target_addr, conn_type == ConnectionType::MANUAL);
}
if (!proxyConnectionFailed) {
// If a connection to the node was attempted, and failure (if any) is not caused by a problem connecting to
// the proxy, mark this as an attempt.
addrman.Attempt(target_addr, fCountFailure);
}
} else if (pszDest && GetNameProxy(proxy)) {
std::string host;
uint16_t port{default_port};
SplitHostPort(std::string(pszDest), port, host);
bool proxyConnectionFailed;
sock = ConnectThroughProxy(proxy, host, port, proxyConnectionFailed);
}
// Check any other resolved address (if any) if we fail to connect
if (!sock) {
continue;
}
NetPermissionFlags permission_flags = NetPermissionFlags::None;
std::vector<NetWhitelistPermissions> whitelist_permissions = conn_type == ConnectionType::MANUAL ? vWhitelistedRangeOutgoing : std::vector<NetWhitelistPermissions>{};
AddWhitelistPermissionFlags(permission_flags, target_addr, whitelist_permissions);
// Add node
NodeId id = GetNewNodeId();
uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
if (!addr_bind.IsValid()) {
addr_bind = GetBindAddress(*sock);
}
CNode* pnode = new CNode(id,
std::move(sock),
target_addr,
CalculateKeyedNetGroup(target_addr),
nonce,
addr_bind,
pszDest ? pszDest : "",
conn_type,
/*inbound_onion=*/false,
CNodeOptions{
.permission_flags = permission_flags,
.i2p_sam_session = std::move(i2p_transient_session),
.recv_flood_size = nReceiveFloodSize,
.use_v2transport = use_v2transport,
});
pnode->AddRef();
// We're making a new connection, harvest entropy from the time (and our peer count)
RandAddEvent((uint32_t)id);
return pnode;
}
return nullptr;
}
void CNode::CloseSocketDisconnect()
{
fDisconnect = true;
LOCK(m_sock_mutex);
if (m_sock) {
LogPrint(BCLog::NET, "disconnecting peer=%d\n", id);
m_sock.reset();
}
m_i2p_sam_session.reset();
}
void CConnman::AddWhitelistPermissionFlags(NetPermissionFlags& flags, const CNetAddr &addr, const std::vector<NetWhitelistPermissions>& ranges) const {
for (const auto& subnet : ranges) {
if (subnet.m_subnet.Match(addr)) {
NetPermissions::AddFlag(flags, subnet.m_flags);
}
}
if (NetPermissions::HasFlag(flags, NetPermissionFlags::Implicit)) {
NetPermissions::ClearFlag(flags, NetPermissionFlags::Implicit);
if (whitelist_forcerelay) NetPermissions::AddFlag(flags, NetPermissionFlags::ForceRelay);
if (whitelist_relay) NetPermissions::AddFlag(flags, NetPermissionFlags::Relay);
NetPermissions::AddFlag(flags, NetPermissionFlags::Mempool);
NetPermissions::AddFlag(flags, NetPermissionFlags::NoBan);
}
}
CService CNode::GetAddrLocal() const
{
AssertLockNotHeld(m_addr_local_mutex);
LOCK(m_addr_local_mutex);
return addrLocal;
}
void CNode::SetAddrLocal(const CService& addrLocalIn) {
AssertLockNotHeld(m_addr_local_mutex);
LOCK(m_addr_local_mutex);
if (addrLocal.IsValid()) {
LogError("Addr local already set for node: %i. Refusing to change from %s to %s\n", id, addrLocal.ToStringAddrPort(), addrLocalIn.ToStringAddrPort());
} else {
addrLocal = addrLocalIn;
}
}
Network CNode::ConnectedThroughNetwork() const
{
return m_inbound_onion ? NET_ONION : addr.GetNetClass();
}
bool CNode::IsConnectedThroughPrivacyNet() const
{
return m_inbound_onion || addr.IsPrivacyNet();
}
#undef X
#define X(name) stats.name = name
void CNode::CopyStats(CNodeStats& stats)
{
stats.nodeid = this->GetId();
X(addr);
X(addrBind);
stats.m_network = ConnectedThroughNetwork();
X(m_last_send);
X(m_last_recv);
X(m_last_tx_time);
X(m_last_block_time);
X(m_connected);
X(m_addr_name);
X(nVersion);
{
LOCK(m_subver_mutex);
X(cleanSubVer);
}
stats.fInbound = IsInboundConn();
X(m_bip152_highbandwidth_to);
X(m_bip152_highbandwidth_from);
{
LOCK(cs_vSend);
X(mapSendBytesPerMsgType);
X(nSendBytes);
}
{
LOCK(cs_vRecv);
X(mapRecvBytesPerMsgType);
X(nRecvBytes);
Transport::Info info = m_transport->GetInfo();
stats.m_transport_type = info.transport_type;
if (info.session_id) stats.m_session_id = HexStr(*info.session_id);
}
X(m_permission_flags);
X(m_last_ping_time);
X(m_min_ping_time);
// Leave string empty if addrLocal invalid (not filled in yet)
CService addrLocalUnlocked = GetAddrLocal();
stats.addrLocal = addrLocalUnlocked.IsValid() ? addrLocalUnlocked.ToStringAddrPort() : "";
X(m_conn_type);
}
#undef X
bool CNode::ReceiveMsgBytes(Span<const uint8_t> msg_bytes, bool& complete)
{
complete = false;
const auto time = GetTime<std::chrono::microseconds>();
LOCK(cs_vRecv);
m_last_recv = std::chrono::duration_cast<std::chrono::seconds>(time);
nRecvBytes += msg_bytes.size();
while (msg_bytes.size() > 0) {
// absorb network data
if (!m_transport->ReceivedBytes(msg_bytes)) {
// Serious transport problem, disconnect from the peer.
return false;
}
if (m_transport->ReceivedMessageComplete()) {
// decompose a transport agnostic CNetMessage from the deserializer
bool reject_message{false};
CNetMessage msg = m_transport->GetReceivedMessage(time, reject_message);
if (reject_message) {
// Message deserialization failed. Drop the message but don't disconnect the peer.
// store the size of the corrupt message
mapRecvBytesPerMsgType.at(NET_MESSAGE_TYPE_OTHER) += msg.m_raw_message_size;
continue;
}
// Store received bytes per message type.
// To prevent a memory DOS, only allow known message types.
auto i = mapRecvBytesPerMsgType.find(msg.m_type);
if (i == mapRecvBytesPerMsgType.end()) {
i = mapRecvBytesPerMsgType.find(NET_MESSAGE_TYPE_OTHER);
}
assert(i != mapRecvBytesPerMsgType.end());
i->second += msg.m_raw_message_size;
// push the message to the process queue,
vRecvMsg.push_back(std::move(msg));
complete = true;
}
}
return true;
}
V1Transport::V1Transport(const NodeId node_id) noexcept
: m_magic_bytes{Params().MessageStart()}, m_node_id{node_id}
{
LOCK(m_recv_mutex);
Reset();
}
Transport::Info V1Transport::GetInfo() const noexcept
{
return {.transport_type = TransportProtocolType::V1, .session_id = {}};
}
int V1Transport::readHeader(Span<const uint8_t> msg_bytes)
{
AssertLockHeld(m_recv_mutex);
// copy data to temporary parsing buffer
unsigned int nRemaining = CMessageHeader::HEADER_SIZE - nHdrPos;
unsigned int nCopy = std::min<unsigned int>(nRemaining, msg_bytes.size());
memcpy(&hdrbuf[nHdrPos], msg_bytes.data(), nCopy);
nHdrPos += nCopy;
// if header incomplete, exit
if (nHdrPos < CMessageHeader::HEADER_SIZE)
return nCopy;
// deserialize to CMessageHeader
try {
hdrbuf >> hdr;
}
catch (const std::exception&) {
LogPrint(BCLog::NET, "Header error: Unable to deserialize, peer=%d\n", m_node_id);
return -1;
}
// Check start string, network magic
if (hdr.pchMessageStart != m_magic_bytes) {
LogPrint(BCLog::NET, "Header error: Wrong MessageStart %s received, peer=%d\n", HexStr(hdr.pchMessageStart), m_node_id);
return -1;
}
// reject messages larger than MAX_SIZE or MAX_PROTOCOL_MESSAGE_LENGTH
if (hdr.nMessageSize > MAX_SIZE || hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
LogPrint(BCLog::NET, "Header error: Size too large (%s, %u bytes), peer=%d\n", SanitizeString(hdr.GetCommand()), hdr.nMessageSize, m_node_id);
return -1;
}
// switch state to reading message data
in_data = true;
return nCopy;
}
int V1Transport::readData(Span<const uint8_t> msg_bytes)
{
AssertLockHeld(m_recv_mutex);
unsigned int nRemaining = hdr.nMessageSize - nDataPos;
unsigned int nCopy = std::min<unsigned int>(nRemaining, msg_bytes.size());
if (vRecv.size() < nDataPos + nCopy) {
// Allocate up to 256 KiB ahead, but never more than the total message size.
vRecv.resize(std::min(hdr.nMessageSize, nDataPos + nCopy + 256 * 1024));
}
hasher.Write(msg_bytes.first(nCopy));
memcpy(&vRecv[nDataPos], msg_bytes.data(), nCopy);
nDataPos += nCopy;
return nCopy;
}
const uint256& V1Transport::GetMessageHash() const
{
AssertLockHeld(m_recv_mutex);
assert(CompleteInternal());
if (data_hash.IsNull())
hasher.Finalize(data_hash);
return data_hash;
}
CNetMessage V1Transport::GetReceivedMessage(const std::chrono::microseconds time, bool& reject_message)
{
AssertLockNotHeld(m_recv_mutex);
// Initialize out parameter
reject_message = false;
// decompose a single CNetMessage from the TransportDeserializer
LOCK(m_recv_mutex);
CNetMessage msg(std::move(vRecv));
// store message type string, time, and sizes
msg.m_type = hdr.GetCommand();
msg.m_time = time;
msg.m_message_size = hdr.nMessageSize;
msg.m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
uint256 hash = GetMessageHash();
// We just received a message off the wire, harvest entropy from the time (and the message checksum)
RandAddEvent(ReadLE32(hash.begin()));
// Check checksum and header message type string
if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
LogPrint(BCLog::NET, "Header error: Wrong checksum (%s, %u bytes), expected %s was %s, peer=%d\n",
SanitizeString(msg.m_type), msg.m_message_size,
HexStr(Span{hash}.first(CMessageHeader::CHECKSUM_SIZE)),
HexStr(hdr.pchChecksum),
m_node_id);
reject_message = true;
} else if (!hdr.IsCommandValid()) {
LogPrint(BCLog::NET, "Header error: Invalid message type (%s, %u bytes), peer=%d\n",
SanitizeString(hdr.GetCommand()), msg.m_message_size, m_node_id);
reject_message = true;
}
// Always reset the network deserializer (prepare for the next message)
Reset();
return msg;
}
bool V1Transport::SetMessageToSend(CSerializedNetMsg& msg) noexcept
{
AssertLockNotHeld(m_send_mutex);
// Determine whether a new message can be set.
LOCK(m_send_mutex);
if (m_sending_header || m_bytes_sent < m_message_to_send.data.size()) return false;
// create dbl-sha256 checksum
uint256 hash = Hash(msg.data);
// create header
CMessageHeader hdr(m_magic_bytes, msg.m_type.c_str(), msg.data.size());
memcpy(hdr.pchChecksum, hash.begin(), CMessageHeader::CHECKSUM_SIZE);
// serialize header
m_header_to_send.clear();
VectorWriter{m_header_to_send, 0, hdr};
// update state
m_message_to_send = std::move(msg);
m_sending_header = true;
m_bytes_sent = 0;
return true;
}
Transport::BytesToSend V1Transport::GetBytesToSend(bool have_next_message) const noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
if (m_sending_header) {
return {Span{m_header_to_send}.subspan(m_bytes_sent),
// We have more to send after the header if the message has payload, or if there
// is a next message after that.
have_next_message || !m_message_to_send.data.empty(),
m_message_to_send.m_type
};
} else {
return {Span{m_message_to_send.data}.subspan(m_bytes_sent),
// We only have more to send after this message's payload if there is another
// message.
have_next_message,
m_message_to_send.m_type
};
}
}
void V1Transport::MarkBytesSent(size_t bytes_sent) noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
m_bytes_sent += bytes_sent;
if (m_sending_header && m_bytes_sent == m_header_to_send.size()) {
// We're done sending a message's header. Switch to sending its data bytes.
m_sending_header = false;
m_bytes_sent = 0;
} else if (!m_sending_header && m_bytes_sent == m_message_to_send.data.size()) {
// We're done sending a message's data. Wipe the data vector to reduce memory consumption.
ClearShrink(m_message_to_send.data);
m_bytes_sent = 0;
}
}
size_t V1Transport::GetSendMemoryUsage() const noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
// Don't count sending-side fields besides m_message_to_send, as they're all small and bounded.
return m_message_to_send.GetMemoryUsage();
}
namespace {
/** List of short messages as defined in BIP324, in order.
*
* Only message types that are actually implemented in this codebase need to be listed, as other
* messages get ignored anyway - whether we know how to decode them or not.
*/
const std::array<std::string, 33> V2_MESSAGE_IDS = {
"", // 12 bytes follow encoding the message type like in V1
NetMsgType::ADDR,
NetMsgType::BLOCK,
NetMsgType::BLOCKTXN,
NetMsgType::CMPCTBLOCK,
NetMsgType::FEEFILTER,
NetMsgType::FILTERADD,
NetMsgType::FILTERCLEAR,
NetMsgType::FILTERLOAD,
NetMsgType::GETBLOCKS,
NetMsgType::GETBLOCKTXN,
NetMsgType::GETDATA,
NetMsgType::GETHEADERS,
NetMsgType::HEADERS,
NetMsgType::INV,
NetMsgType::MEMPOOL,
NetMsgType::MERKLEBLOCK,
NetMsgType::NOTFOUND,
NetMsgType::PING,
NetMsgType::PONG,
NetMsgType::SENDCMPCT,
NetMsgType::TX,
NetMsgType::GETCFILTERS,
NetMsgType::CFILTER,
NetMsgType::GETCFHEADERS,
NetMsgType::CFHEADERS,
NetMsgType::GETCFCHECKPT,
NetMsgType::CFCHECKPT,
NetMsgType::ADDRV2,
// Unimplemented message types that are assigned in BIP324:
"",
"",
"",
""
};
class V2MessageMap
{
std::unordered_map<std::string, uint8_t> m_map;
public:
V2MessageMap() noexcept
{
for (size_t i = 1; i < std::size(V2_MESSAGE_IDS); ++i) {
m_map.emplace(V2_MESSAGE_IDS[i], i);
}
}
std::optional<uint8_t> operator()(const std::string& message_name) const noexcept
{
auto it = m_map.find(message_name);
if (it == m_map.end()) return std::nullopt;
return it->second;
}
};
const V2MessageMap V2_MESSAGE_MAP;
std::vector<uint8_t> GenerateRandomGarbage() noexcept
{
std::vector<uint8_t> ret;
FastRandomContext rng;
ret.resize(rng.randrange(V2Transport::MAX_GARBAGE_LEN + 1));
rng.fillrand(MakeWritableByteSpan(ret));
return ret;
}
} // namespace
void V2Transport::StartSendingHandshake() noexcept
{
AssertLockHeld(m_send_mutex);
Assume(m_send_state == SendState::AWAITING_KEY);
Assume(m_send_buffer.empty());
// Initialize the send buffer with ellswift pubkey + provided garbage.
m_send_buffer.resize(EllSwiftPubKey::size() + m_send_garbage.size());
std::copy(std::begin(m_cipher.GetOurPubKey()), std::end(m_cipher.GetOurPubKey()), MakeWritableByteSpan(m_send_buffer).begin());
std::copy(m_send_garbage.begin(), m_send_garbage.end(), m_send_buffer.begin() + EllSwiftPubKey::size());
// We cannot wipe m_send_garbage as it will still be used as AAD later in the handshake.
}
V2Transport::V2Transport(NodeId nodeid, bool initiating, const CKey& key, Span<const std::byte> ent32, std::vector<uint8_t> garbage) noexcept
: m_cipher{key, ent32}, m_initiating{initiating}, m_nodeid{nodeid},
m_v1_fallback{nodeid},
m_recv_state{initiating ? RecvState::KEY : RecvState::KEY_MAYBE_V1},
m_send_garbage{std::move(garbage)},
m_send_state{initiating ? SendState::AWAITING_KEY : SendState::MAYBE_V1}
{
Assume(m_send_garbage.size() <= MAX_GARBAGE_LEN);
// Start sending immediately if we're the initiator of the connection.
if (initiating) {
LOCK(m_send_mutex);
StartSendingHandshake();
}
}
V2Transport::V2Transport(NodeId nodeid, bool initiating) noexcept
: V2Transport{nodeid, initiating, GenerateRandomKey(),
MakeByteSpan(GetRandHash()), GenerateRandomGarbage()} {}
void V2Transport::SetReceiveState(RecvState recv_state) noexcept
{
AssertLockHeld(m_recv_mutex);
// Enforce allowed state transitions.
switch (m_recv_state) {
case RecvState::KEY_MAYBE_V1:
Assume(recv_state == RecvState::KEY || recv_state == RecvState::V1);
break;
case RecvState::KEY:
Assume(recv_state == RecvState::GARB_GARBTERM);
break;
case RecvState::GARB_GARBTERM:
Assume(recv_state == RecvState::VERSION);
break;
case RecvState::VERSION:
Assume(recv_state == RecvState::APP);
break;
case RecvState::APP:
Assume(recv_state == RecvState::APP_READY);
break;
case RecvState::APP_READY:
Assume(recv_state == RecvState::APP);
break;
case RecvState::V1:
Assume(false); // V1 state cannot be left
break;
}
// Change state.
m_recv_state = recv_state;
}
void V2Transport::SetSendState(SendState send_state) noexcept
{
AssertLockHeld(m_send_mutex);
// Enforce allowed state transitions.
switch (m_send_state) {
case SendState::MAYBE_V1:
Assume(send_state == SendState::V1 || send_state == SendState::AWAITING_KEY);
break;
case SendState::AWAITING_KEY:
Assume(send_state == SendState::READY);
break;
case SendState::READY:
case SendState::V1:
Assume(false); // Final states
break;
}
// Change state.
m_send_state = send_state;
}
bool V2Transport::ReceivedMessageComplete() const noexcept
{
AssertLockNotHeld(m_recv_mutex);
LOCK(m_recv_mutex);
if (m_recv_state == RecvState::V1) return m_v1_fallback.ReceivedMessageComplete();
return m_recv_state == RecvState::APP_READY;
}
void V2Transport::ProcessReceivedMaybeV1Bytes() noexcept
{
AssertLockHeld(m_recv_mutex);
AssertLockNotHeld(m_send_mutex);
Assume(m_recv_state == RecvState::KEY_MAYBE_V1);
// We still have to determine if this is a v1 or v2 connection. The bytes being received could
// be the beginning of either a v1 packet (network magic + "version\x00\x00\x00\x00\x00"), or
// of a v2 public key. BIP324 specifies that a mismatch with this 16-byte string should trigger
// sending of the key.
std::array<uint8_t, V1_PREFIX_LEN> v1_prefix = {0, 0, 0, 0, 'v', 'e', 'r', 's', 'i', 'o', 'n', 0, 0, 0, 0, 0};
std::copy(std::begin(Params().MessageStart()), std::end(Params().MessageStart()), v1_prefix.begin());
Assume(m_recv_buffer.size() <= v1_prefix.size());
if (!std::equal(m_recv_buffer.begin(), m_recv_buffer.end(), v1_prefix.begin())) {
// Mismatch with v1 prefix, so we can assume a v2 connection.
SetReceiveState(RecvState::KEY); // Convert to KEY state, leaving received bytes around.
// Transition the sender to AWAITING_KEY state and start sending.
LOCK(m_send_mutex);
SetSendState(SendState::AWAITING_KEY);
StartSendingHandshake();
} else if (m_recv_buffer.size() == v1_prefix.size()) {
// Full match with the v1 prefix, so fall back to v1 behavior.
LOCK(m_send_mutex);
Span<const uint8_t> feedback{m_recv_buffer};
// Feed already received bytes to v1 transport. It should always accept these, because it's
// less than the size of a v1 header, and these are the first bytes fed to m_v1_fallback.
bool ret = m_v1_fallback.ReceivedBytes(feedback);
Assume(feedback.empty());
Assume(ret);
SetReceiveState(RecvState::V1);
SetSendState(SendState::V1);
// Reset v2 transport buffers to save memory.
ClearShrink(m_recv_buffer);
ClearShrink(m_send_buffer);
} else {
// We have not received enough to distinguish v1 from v2 yet. Wait until more bytes come.
}
}
bool V2Transport::ProcessReceivedKeyBytes() noexcept
{
AssertLockHeld(m_recv_mutex);
AssertLockNotHeld(m_send_mutex);
Assume(m_recv_state == RecvState::KEY);
Assume(m_recv_buffer.size() <= EllSwiftPubKey::size());
// As a special exception, if bytes 4-16 of the key on a responder connection match the
// corresponding bytes of a V1 version message, but bytes 0-4 don't match the network magic
// (if they did, we'd have switched to V1 state already), assume this is a peer from
// another network, and disconnect them. They will almost certainly disconnect us too when
// they receive our uniformly random key and garbage, but detecting this case specially
// means we can log it.
static constexpr std::array<uint8_t, 12> MATCH = {'v', 'e', 'r', 's', 'i', 'o', 'n', 0, 0, 0, 0, 0};
static constexpr size_t OFFSET = std::tuple_size_v<MessageStartChars>;
if (!m_initiating && m_recv_buffer.size() >= OFFSET + MATCH.size()) {
if (std::equal(MATCH.begin(), MATCH.end(), m_recv_buffer.begin() + OFFSET)) {
LogPrint(BCLog::NET, "V2 transport error: V1 peer with wrong MessageStart %s\n",
HexStr(Span(m_recv_buffer).first(OFFSET)));
return false;
}
}
if (m_recv_buffer.size() == EllSwiftPubKey::size()) {
// Other side's key has been fully received, and can now be Diffie-Hellman combined with
// our key to initialize the encryption ciphers.
// Initialize the ciphers.
EllSwiftPubKey ellswift(MakeByteSpan(m_recv_buffer));
LOCK(m_send_mutex);
m_cipher.Initialize(ellswift, m_initiating);
// Switch receiver state to GARB_GARBTERM.
SetReceiveState(RecvState::GARB_GARBTERM);
m_recv_buffer.clear();
// Switch sender state to READY.
SetSendState(SendState::READY);
// Append the garbage terminator to the send buffer.
m_send_buffer.resize(m_send_buffer.size() + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
std::copy(m_cipher.GetSendGarbageTerminator().begin(),
m_cipher.GetSendGarbageTerminator().end(),
MakeWritableByteSpan(m_send_buffer).last(BIP324Cipher::GARBAGE_TERMINATOR_LEN).begin());
// Construct version packet in the send buffer, with the sent garbage data as AAD.
m_send_buffer.resize(m_send_buffer.size() + BIP324Cipher::EXPANSION + VERSION_CONTENTS.size());
m_cipher.Encrypt(
/*contents=*/VERSION_CONTENTS,
/*aad=*/MakeByteSpan(m_send_garbage),
/*ignore=*/false,
/*output=*/MakeWritableByteSpan(m_send_buffer).last(BIP324Cipher::EXPANSION + VERSION_CONTENTS.size()));
// We no longer need the garbage.
ClearShrink(m_send_garbage);
} else {
// We still have to receive more key bytes.
}
return true;
}
bool V2Transport::ProcessReceivedGarbageBytes() noexcept
{
AssertLockHeld(m_recv_mutex);
Assume(m_recv_state == RecvState::GARB_GARBTERM);
Assume(m_recv_buffer.size() <= MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
if (m_recv_buffer.size() >= BIP324Cipher::GARBAGE_TERMINATOR_LEN) {
if (MakeByteSpan(m_recv_buffer).last(BIP324Cipher::GARBAGE_TERMINATOR_LEN) == m_cipher.GetReceiveGarbageTerminator()) {
// Garbage terminator received. Store garbage to authenticate it as AAD later.
m_recv_aad = std::move(m_recv_buffer);
m_recv_aad.resize(m_recv_aad.size() - BIP324Cipher::GARBAGE_TERMINATOR_LEN);
m_recv_buffer.clear();
SetReceiveState(RecvState::VERSION);
} else if (m_recv_buffer.size() == MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN) {
// We've reached the maximum length for garbage + garbage terminator, and the
// terminator still does not match. Abort.
LogPrint(BCLog::NET, "V2 transport error: missing garbage terminator, peer=%d\n", m_nodeid);
return false;
} else {
// We still need to receive more garbage and/or garbage terminator bytes.
}
} else {
// We have less than GARBAGE_TERMINATOR_LEN (16) bytes, so we certainly need to receive
// more first.
}
return true;
}
bool V2Transport::ProcessReceivedPacketBytes() noexcept
{
AssertLockHeld(m_recv_mutex);
Assume(m_recv_state == RecvState::VERSION || m_recv_state == RecvState::APP);
// The maximum permitted contents length for a packet, consisting of:
// - 0x00 byte: indicating long message type encoding
// - 12 bytes of message type
// - payload
static constexpr size_t MAX_CONTENTS_LEN =
1 + CMessageHeader::COMMAND_SIZE +
std::min<size_t>(MAX_SIZE, MAX_PROTOCOL_MESSAGE_LENGTH);
if (m_recv_buffer.size() == BIP324Cipher::LENGTH_LEN) {
// Length descriptor received.
m_recv_len = m_cipher.DecryptLength(MakeByteSpan(m_recv_buffer));
if (m_recv_len > MAX_CONTENTS_LEN) {
LogPrint(BCLog::NET, "V2 transport error: packet too large (%u bytes), peer=%d\n", m_recv_len, m_nodeid);
return false;
}
} else if (m_recv_buffer.size() > BIP324Cipher::LENGTH_LEN && m_recv_buffer.size() == m_recv_len + BIP324Cipher::EXPANSION) {
// Ciphertext received, decrypt it into m_recv_decode_buffer.
// Note that it is impossible to reach this branch without hitting the branch above first,
// as GetMaxBytesToProcess only allows up to LENGTH_LEN into the buffer before that point.
m_recv_decode_buffer.resize(m_recv_len);
bool ignore{false};
bool ret = m_cipher.Decrypt(
/*input=*/MakeByteSpan(m_recv_buffer).subspan(BIP324Cipher::LENGTH_LEN),
/*aad=*/MakeByteSpan(m_recv_aad),
/*ignore=*/ignore,
/*contents=*/MakeWritableByteSpan(m_recv_decode_buffer));
if (!ret) {
LogPrint(BCLog::NET, "V2 transport error: packet decryption failure (%u bytes), peer=%d\n", m_recv_len, m_nodeid);
return false;
}
// We have decrypted a valid packet with the AAD we expected, so clear the expected AAD.
ClearShrink(m_recv_aad);
// Feed the last 4 bytes of the Poly1305 authentication tag (and its timing) into our RNG.
RandAddEvent(ReadLE32(m_recv_buffer.data() + m_recv_buffer.size() - 4));
// At this point we have a valid packet decrypted into m_recv_decode_buffer. If it's not a
// decoy, which we simply ignore, use the current state to decide what to do with it.
if (!ignore) {
switch (m_recv_state) {
case RecvState::VERSION:
// Version message received; transition to application phase. The contents is
// ignored, but can be used for future extensions.
SetReceiveState(RecvState::APP);
break;
case RecvState::APP:
// Application message decrypted correctly. It can be extracted using GetMessage().
SetReceiveState(RecvState::APP_READY);
break;
default:
// Any other state is invalid (this function should not have been called).
Assume(false);
}
}
// Wipe the receive buffer where the next packet will be received into.
ClearShrink(m_recv_buffer);
// In all but APP_READY state, we can wipe the decoded contents.
if (m_recv_state != RecvState::APP_READY) ClearShrink(m_recv_decode_buffer);
} else {
// We either have less than 3 bytes, so we don't know the packet's length yet, or more
// than 3 bytes but less than the packet's full ciphertext. Wait until those arrive.
}
return true;
}
size_t V2Transport::GetMaxBytesToProcess() noexcept
{
AssertLockHeld(m_recv_mutex);
switch (m_recv_state) {
case RecvState::KEY_MAYBE_V1:
// During the KEY_MAYBE_V1 state we do not allow more than the length of v1 prefix into the
// receive buffer.
Assume(m_recv_buffer.size() <= V1_PREFIX_LEN);
// As long as we're not sure if this is a v1 or v2 connection, don't receive more than what
// is strictly necessary to distinguish the two (16 bytes). If we permitted more than
// the v1 header size (24 bytes), we may not be able to feed the already-received bytes
// back into the m_v1_fallback V1 transport.
return V1_PREFIX_LEN - m_recv_buffer.size();
case RecvState::KEY:
// During the KEY state, we only allow the 64-byte key into the receive buffer.
Assume(m_recv_buffer.size() <= EllSwiftPubKey::size());
// As long as we have not received the other side's public key, don't receive more than
// that (64 bytes), as garbage follows, and locating the garbage terminator requires the
// key exchange first.
return EllSwiftPubKey::size() - m_recv_buffer.size();
case RecvState::GARB_GARBTERM:
// Process garbage bytes one by one (because terminator may appear anywhere).
return 1;
case RecvState::VERSION:
case RecvState::APP:
// These three states all involve decoding a packet. Process the length descriptor first,
// so that we know where the current packet ends (and we don't process bytes from the next
// packet or decoy yet). Then, process the ciphertext bytes of the current packet.
if (m_recv_buffer.size() < BIP324Cipher::LENGTH_LEN) {
return BIP324Cipher::LENGTH_LEN - m_recv_buffer.size();
} else {
// Note that BIP324Cipher::EXPANSION is the total difference between contents size
// and encoded packet size, which includes the 3 bytes due to the packet length.
// When transitioning from receiving the packet length to receiving its ciphertext,
// the encrypted packet length is left in the receive buffer.
return BIP324Cipher::EXPANSION + m_recv_len - m_recv_buffer.size();
}
case RecvState::APP_READY:
// No bytes can be processed until GetMessage() is called.
return 0;
case RecvState::V1:
// Not allowed (must be dealt with by the caller).
Assume(false);
return 0;
}
Assume(false); // unreachable
return 0;
}
bool V2Transport::ReceivedBytes(Span<const uint8_t>& msg_bytes) noexcept
{
AssertLockNotHeld(m_recv_mutex);
/** How many bytes to allocate in the receive buffer at most above what is received so far. */
static constexpr size_t MAX_RESERVE_AHEAD = 256 * 1024;
LOCK(m_recv_mutex);
if (m_recv_state == RecvState::V1) return m_v1_fallback.ReceivedBytes(msg_bytes);
// Process the provided bytes in msg_bytes in a loop. In each iteration a nonzero number of
// bytes (decided by GetMaxBytesToProcess) are taken from the beginning om msg_bytes, and
// appended to m_recv_buffer. Then, depending on the receiver state, one of the
// ProcessReceived*Bytes functions is called to process the bytes in that buffer.
while (!msg_bytes.empty()) {
// Decide how many bytes to copy from msg_bytes to m_recv_buffer.
size_t max_read = GetMaxBytesToProcess();
// Reserve space in the buffer if there is not enough.
if (m_recv_buffer.size() + std::min(msg_bytes.size(), max_read) > m_recv_buffer.capacity()) {
switch (m_recv_state) {
case RecvState::KEY_MAYBE_V1:
case RecvState::KEY:
case RecvState::GARB_GARBTERM:
// During the initial states (key/garbage), allocate once to fit the maximum (4111
// bytes).
m_recv_buffer.reserve(MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
break;
case RecvState::VERSION:
case RecvState::APP: {
// During states where a packet is being received, as much as is expected but never
// more than MAX_RESERVE_AHEAD bytes in addition to what is received so far.
// This means attackers that want to cause us to waste allocated memory are limited
// to MAX_RESERVE_AHEAD above the largest allowed message contents size, and to
// MAX_RESERVE_AHEAD more than they've actually sent us.
size_t alloc_add = std::min(max_read, msg_bytes.size() + MAX_RESERVE_AHEAD);
m_recv_buffer.reserve(m_recv_buffer.size() + alloc_add);
break;
}
case RecvState::APP_READY:
// The buffer is empty in this state.
Assume(m_recv_buffer.empty());
break;
case RecvState::V1:
// Should have bailed out above.
Assume(false);
break;
}
}
// Can't read more than provided input.
max_read = std::min(msg_bytes.size(), max_read);
// Copy data to buffer.
m_recv_buffer.insert(m_recv_buffer.end(), UCharCast(msg_bytes.data()), UCharCast(msg_bytes.data() + max_read));
msg_bytes = msg_bytes.subspan(max_read);
// Process data in the buffer.
switch (m_recv_state) {
case RecvState::KEY_MAYBE_V1:
ProcessReceivedMaybeV1Bytes();
if (m_recv_state == RecvState::V1) return true;
break;
case RecvState::KEY:
if (!ProcessReceivedKeyBytes()) return false;
break;
case RecvState::GARB_GARBTERM:
if (!ProcessReceivedGarbageBytes()) return false;
break;
case RecvState::VERSION:
case RecvState::APP:
if (!ProcessReceivedPacketBytes()) return false;
break;
case RecvState::APP_READY:
return true;
case RecvState::V1:
// We should have bailed out before.
Assume(false);
break;
}
// Make sure we have made progress before continuing.
Assume(max_read > 0);
}
return true;
}
std::optional<std::string> V2Transport::GetMessageType(Span<const uint8_t>& contents) noexcept
{
if (contents.size() == 0) return std::nullopt; // Empty contents
uint8_t first_byte = contents[0];
contents = contents.subspan(1); // Strip first byte.
if (first_byte != 0) {
// Short (1 byte) encoding.
if (first_byte < std::size(V2_MESSAGE_IDS)) {
// Valid short message id.
return V2_MESSAGE_IDS[first_byte];
} else {
// Unknown short message id.
return std::nullopt;
}
}
if (contents.size() < CMessageHeader::COMMAND_SIZE) {
return std::nullopt; // Long encoding needs 12 message type bytes.
}
size_t msg_type_len{0};
while (msg_type_len < CMessageHeader::COMMAND_SIZE && contents[msg_type_len] != 0) {
// Verify that message type bytes before the first 0x00 are in range.
if (contents[msg_type_len] < ' ' || contents[msg_type_len] > 0x7F) {
return {};
}
++msg_type_len;
}
std::string ret{reinterpret_cast<const char*>(contents.data()), msg_type_len};
while (msg_type_len < CMessageHeader::COMMAND_SIZE) {
// Verify that message type bytes after the first 0x00 are also 0x00.
if (contents[msg_type_len] != 0) return {};
++msg_type_len;
}
// Strip message type bytes of contents.
contents = contents.subspan(CMessageHeader::COMMAND_SIZE);
return ret;
}
CNetMessage V2Transport::GetReceivedMessage(std::chrono::microseconds time, bool& reject_message) noexcept
{
AssertLockNotHeld(m_recv_mutex);
LOCK(m_recv_mutex);
if (m_recv_state == RecvState::V1) return m_v1_fallback.GetReceivedMessage(time, reject_message);
Assume(m_recv_state == RecvState::APP_READY);
Span<const uint8_t> contents{m_recv_decode_buffer};
auto msg_type = GetMessageType(contents);
CNetMessage msg{DataStream{}};
// Note that BIP324Cipher::EXPANSION also includes the length descriptor size.
msg.m_raw_message_size = m_recv_decode_buffer.size() + BIP324Cipher::EXPANSION;
if (msg_type) {
reject_message = false;
msg.m_type = std::move(*msg_type);
msg.m_time = time;
msg.m_message_size = contents.size();
msg.m_recv.resize(contents.size());
std::copy(contents.begin(), contents.end(), UCharCast(msg.m_recv.data()));
} else {
LogPrint(BCLog::NET, "V2 transport error: invalid message type (%u bytes contents), peer=%d\n", m_recv_decode_buffer.size(), m_nodeid);
reject_message = true;
}
ClearShrink(m_recv_decode_buffer);
SetReceiveState(RecvState::APP);
return msg;
}
bool V2Transport::SetMessageToSend(CSerializedNetMsg& msg) noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
if (m_send_state == SendState::V1) return m_v1_fallback.SetMessageToSend(msg);
// We only allow adding a new message to be sent when in the READY state (so the packet cipher
// is available) and the send buffer is empty. This limits the number of messages in the send
// buffer to just one, and leaves the responsibility for queueing them up to the caller.
if (!(m_send_state == SendState::READY && m_send_buffer.empty())) return false;
// Construct contents (encoding message type + payload).
std::vector<uint8_t> contents;
auto short_message_id = V2_MESSAGE_MAP(msg.m_type);
if (short_message_id) {
contents.resize(1 + msg.data.size());
contents[0] = *short_message_id;
std::copy(msg.data.begin(), msg.data.end(), contents.begin() + 1);
} else {
// Initialize with zeroes, and then write the message type string starting at offset 1.
// This means contents[0] and the unused positions in contents[1..13] remain 0x00.
contents.resize(1 + CMessageHeader::COMMAND_SIZE + msg.data.size(), 0);
std::copy(msg.m_type.begin(), msg.m_type.end(), contents.data() + 1);
std::copy(msg.data.begin(), msg.data.end(), contents.begin() + 1 + CMessageHeader::COMMAND_SIZE);
}
// Construct ciphertext in send buffer.
m_send_buffer.resize(contents.size() + BIP324Cipher::EXPANSION);
m_cipher.Encrypt(MakeByteSpan(contents), {}, false, MakeWritableByteSpan(m_send_buffer));
m_send_type = msg.m_type;
// Release memory
ClearShrink(msg.data);
return true;
}
Transport::BytesToSend V2Transport::GetBytesToSend(bool have_next_message) const noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
if (m_send_state == SendState::V1) return m_v1_fallback.GetBytesToSend(have_next_message);
if (m_send_state == SendState::MAYBE_V1) Assume(m_send_buffer.empty());
Assume(m_send_pos <= m_send_buffer.size());
return {
Span{m_send_buffer}.subspan(m_send_pos),
// We only have more to send after the current m_send_buffer if there is a (next)
// message to be sent, and we're capable of sending packets. */
have_next_message && m_send_state == SendState::READY,
m_send_type
};
}
void V2Transport::MarkBytesSent(size_t bytes_sent) noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
if (m_send_state == SendState::V1) return m_v1_fallback.MarkBytesSent(bytes_sent);
if (m_send_state == SendState::AWAITING_KEY && m_send_pos == 0 && bytes_sent > 0) {
LogPrint(BCLog::NET, "start sending v2 handshake to peer=%d\n", m_nodeid);
}
m_send_pos += bytes_sent;
Assume(m_send_pos <= m_send_buffer.size());
if (m_send_pos >= CMessageHeader::HEADER_SIZE) {
m_sent_v1_header_worth = true;
}
// Wipe the buffer when everything is sent.
if (m_send_pos == m_send_buffer.size()) {
m_send_pos = 0;
ClearShrink(m_send_buffer);
}
}
bool V2Transport::ShouldReconnectV1() const noexcept
{
AssertLockNotHeld(m_send_mutex);
AssertLockNotHeld(m_recv_mutex);
// Only outgoing connections need reconnection.
if (!m_initiating) return false;
LOCK(m_recv_mutex);
// We only reconnect in the very first state and when the receive buffer is empty. Together
// these conditions imply nothing has been received so far.
if (m_recv_state != RecvState::KEY) return false;
if (!m_recv_buffer.empty()) return false;
// Check if we've sent enough for the other side to disconnect us (if it was V1).
LOCK(m_send_mutex);
return m_sent_v1_header_worth;
}
size_t V2Transport::GetSendMemoryUsage() const noexcept
{
AssertLockNotHeld(m_send_mutex);
LOCK(m_send_mutex);
if (m_send_state == SendState::V1) return m_v1_fallback.GetSendMemoryUsage();
return sizeof(m_send_buffer) + memusage::DynamicUsage(m_send_buffer);
}
Transport::Info V2Transport::GetInfo() const noexcept
{
AssertLockNotHeld(m_recv_mutex);
LOCK(m_recv_mutex);
if (m_recv_state == RecvState::V1) return m_v1_fallback.GetInfo();
Transport::Info info;
// Do not report v2 and session ID until the version packet has been received
// and verified (confirming that the other side very likely has the same keys as us).
if (m_recv_state != RecvState::KEY_MAYBE_V1 && m_recv_state != RecvState::KEY &&
m_recv_state != RecvState::GARB_GARBTERM && m_recv_state != RecvState::VERSION) {
info.transport_type = TransportProtocolType::V2;
info.session_id = uint256(MakeUCharSpan(m_cipher.GetSessionID()));
} else {
info.transport_type = TransportProtocolType::DETECTING;
}
return info;
}
std::pair<size_t, bool> CConnman::SocketSendData(CNode& node) const
{
auto it = node.vSendMsg.begin();
size_t nSentSize = 0;
bool data_left{false}; //!< second return value (whether unsent data remains)
std::optional<bool> expected_more;
while (true) {
if (it != node.vSendMsg.end()) {
// If possible, move one message from the send queue to the transport. This fails when
// there is an existing message still being sent, or (for v2 transports) when the
// handshake has not yet completed.
size_t memusage = it->GetMemoryUsage();
if (node.m_transport->SetMessageToSend(*it)) {
// Update memory usage of send buffer (as *it will be deleted).
node.m_send_memusage -= memusage;
++it;
}
}
const auto& [data, more, msg_type] = node.m_transport->GetBytesToSend(it != node.vSendMsg.end());
// We rely on the 'more' value returned by GetBytesToSend to correctly predict whether more
// bytes are still to be sent, to correctly set the MSG_MORE flag. As a sanity check,
// verify that the previously returned 'more' was correct.
if (expected_more.has_value()) Assume(!data.empty() == *expected_more);
expected_more = more;
data_left = !data.empty(); // will be overwritten on next loop if all of data gets sent
int nBytes = 0;
if (!data.empty()) {
LOCK(node.m_sock_mutex);
// There is no socket in case we've already disconnected, or in test cases without
// real connections. In these cases, we bail out immediately and just leave things
// in the send queue and transport.
if (!node.m_sock) {
break;
}
int flags = MSG_NOSIGNAL | MSG_DONTWAIT;
#ifdef MSG_MORE
if (more) {
flags |= MSG_MORE;
}
#endif
nBytes = node.m_sock->Send(reinterpret_cast<const char*>(data.data()), data.size(), flags);
}
if (nBytes > 0) {
node.m_last_send = GetTime<std::chrono::seconds>();
node.nSendBytes += nBytes;
// Notify transport that bytes have been processed.
node.m_transport->MarkBytesSent(nBytes);
// Update statistics per message type.
if (!msg_type.empty()) { // don't report v2 handshake bytes for now
node.AccountForSentBytes(msg_type, nBytes);
}
nSentSize += nBytes;
if ((size_t)nBytes != data.size()) {
// could not send full message; stop sending more
break;
}
} else {
if (nBytes < 0) {
// error
int nErr = WSAGetLastError();
if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS) {
LogPrint(BCLog::NET, "socket send error for peer=%d: %s\n", node.GetId(), NetworkErrorString(nErr));
node.CloseSocketDisconnect();
}
}
break;
}
}
node.fPauseSend = node.m_send_memusage + node.m_transport->GetSendMemoryUsage() > nSendBufferMaxSize;
if (it == node.vSendMsg.end()) {
assert(node.m_send_memusage == 0);
}
node.vSendMsg.erase(node.vSendMsg.begin(), it);
return {nSentSize, data_left};
}
/** Try to find a connection to evict when the node is full.
* Extreme care must be taken to avoid opening the node to attacker
* triggered network partitioning.
* The strategy used here is to protect a small number of peers
* for each of several distinct characteristics which are difficult
* to forge. In order to partition a node the attacker must be
* simultaneously better at all of them than honest peers.
*/
bool CConnman::AttemptToEvictConnection()
{
std::vector<NodeEvictionCandidate> vEvictionCandidates;
{
LOCK(m_nodes_mutex);
for (const CNode* node : m_nodes) {
if (node->fDisconnect)
continue;
NodeEvictionCandidate candidate{
.id = node->GetId(),
.m_connected = node->m_connected,
.m_min_ping_time = node->m_min_ping_time,
.m_last_block_time = node->m_last_block_time,
.m_last_tx_time = node->m_last_tx_time,
.fRelevantServices = node->m_has_all_wanted_services,
.m_relay_txs = node->m_relays_txs.load(),
.fBloomFilter = node->m_bloom_filter_loaded.load(),
.nKeyedNetGroup = node->nKeyedNetGroup,
.prefer_evict = node->m_prefer_evict,
.m_is_local = node->addr.IsLocal(),
.m_network = node->ConnectedThroughNetwork(),
.m_noban = node->HasPermission(NetPermissionFlags::NoBan),
.m_conn_type = node->m_conn_type,
};
vEvictionCandidates.push_back(candidate);
}
}
const std::optional<NodeId> node_id_to_evict = SelectNodeToEvict(std::move(vEvictionCandidates));
if (!node_id_to_evict) {
return false;
}
LOCK(m_nodes_mutex);
for (CNode* pnode : m_nodes) {
if (pnode->GetId() == *node_id_to_evict) {
LogPrint(BCLog::NET, "selected %s connection for eviction peer=%d; disconnecting\n", pnode->ConnectionTypeAsString(), pnode->GetId());
pnode->fDisconnect = true;
return true;
}
}
return false;
}
void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
struct sockaddr_storage sockaddr;
socklen_t len = sizeof(sockaddr);
auto sock = hListenSocket.sock->Accept((struct sockaddr*)&sockaddr, &len);
CAddress addr;
if (!sock) {
const int nErr = WSAGetLastError();
if (nErr != WSAEWOULDBLOCK) {
LogPrintf("socket error accept failed: %s\n", NetworkErrorString(nErr));
}
return;
}
if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr)) {
LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "Unknown socket family\n");
} else {
addr = CAddress{MaybeFlipIPv6toCJDNS(addr), NODE_NONE};
}
const CAddress addr_bind{MaybeFlipIPv6toCJDNS(GetBindAddress(*sock)), NODE_NONE};
NetPermissionFlags permission_flags = NetPermissionFlags::None;
hListenSocket.AddSocketPermissionFlags(permission_flags);
CreateNodeFromAcceptedSocket(std::move(sock), permission_flags, addr_bind, addr);
}
void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
NetPermissionFlags permission_flags,
const CAddress& addr_bind,
const CAddress& addr)
{
int nInbound = 0;
AddWhitelistPermissionFlags(permission_flags, addr, vWhitelistedRangeIncoming);
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->IsInboundConn()) nInbound++;
}
}
if (!fNetworkActive) {
LogPrint(BCLog::NET, "connection from %s dropped: not accepting new connections\n", addr.ToStringAddrPort());
return;
}
if (!sock->IsSelectable()) {
LogPrintf("connection from %s dropped: non-selectable socket\n", addr.ToStringAddrPort());
return;
}
// According to the internet TCP_NODELAY is not carried into accepted sockets
// on all platforms. Set it again here just to be sure.
const int on{1};
if (sock->SetSockOpt(IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) == SOCKET_ERROR) {
LogPrint(BCLog::NET, "connection from %s: unable to set TCP_NODELAY, continuing anyway\n",
addr.ToStringAddrPort());
}
// Don't accept connections from banned peers.
bool banned = m_banman && m_banman->IsBanned(addr);
if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && banned)
{
LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToStringAddrPort());
return;
}
// Only accept connections from discouraged peers if our inbound slots aren't (almost) full.
bool discouraged = m_banman && m_banman->IsDiscouraged(addr);
if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && nInbound + 1 >= m_max_inbound && discouraged)
{
LogPrint(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToStringAddrPort());
return;
}
if (nInbound >= m_max_inbound)
{
if (!AttemptToEvictConnection()) {
// No connection to evict, disconnect the new connection
LogPrint(BCLog::NET, "failed to find an eviction candidate - connection dropped (full)\n");
return;
}
}
NodeId id = GetNewNodeId();
uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
const bool inbound_onion = std::find(m_onion_binds.begin(), m_onion_binds.end(), addr_bind) != m_onion_binds.end();
// The V2Transport transparently falls back to V1 behavior when an incoming V1 connection is
// detected, so use it whenever we signal NODE_P2P_V2.
const bool use_v2transport(nLocalServices & NODE_P2P_V2);
CNode* pnode = new CNode(id,
std::move(sock),
addr,
CalculateKeyedNetGroup(addr),
nonce,
addr_bind,
/*addrNameIn=*/"",
ConnectionType::INBOUND,
inbound_onion,
CNodeOptions{
.permission_flags = permission_flags,
.prefer_evict = discouraged,
.recv_flood_size = nReceiveFloodSize,
.use_v2transport = use_v2transport,
});
pnode->AddRef();
m_msgproc->InitializeNode(*pnode, nLocalServices);
LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToStringAddrPort());
{
LOCK(m_nodes_mutex);
m_nodes.push_back(pnode);
}
// We received a new connection, harvest entropy from the time (and our peer count)
RandAddEvent((uint32_t)id);
}
bool CConnman::AddConnection(const std::string& address, ConnectionType conn_type, bool use_v2transport = false)
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
std::optional<int> max_connections;
switch (conn_type) {
case ConnectionType::INBOUND:
case ConnectionType::MANUAL:
return false;
case ConnectionType::OUTBOUND_FULL_RELAY:
max_connections = m_max_outbound_full_relay;
break;
case ConnectionType::BLOCK_RELAY:
max_connections = m_max_outbound_block_relay;
break;
// no limit for ADDR_FETCH because -seednode has no limit either
case ConnectionType::ADDR_FETCH:
break;
// no limit for FEELER connections since they're short-lived
case ConnectionType::FEELER:
break;
} // no default case, so the compiler can warn about missing cases
// Count existing connections
int existing_connections = WITH_LOCK(m_nodes_mutex,
return std::count_if(m_nodes.begin(), m_nodes.end(), [conn_type](CNode* node) { return node->m_conn_type == conn_type; }););
// Max connections of specified type already exist
if (max_connections != std::nullopt && existing_connections >= max_connections) return false;
// Max total outbound connections already exist
CSemaphoreGrant grant(*semOutbound, true);
if (!grant) return false;
OpenNetworkConnection(CAddress(), false, std::move(grant), address.c_str(), conn_type, /*use_v2transport=*/use_v2transport);
return true;
}
void CConnman::DisconnectNodes()
{
AssertLockNotHeld(m_nodes_mutex);
AssertLockNotHeld(m_reconnections_mutex);
// Use a temporary variable to accumulate desired reconnections, so we don't need
// m_reconnections_mutex while holding m_nodes_mutex.
decltype(m_reconnections) reconnections_to_add;
{
LOCK(m_nodes_mutex);
if (!fNetworkActive) {
// Disconnect any connected nodes
for (CNode* pnode : m_nodes) {
if (!pnode->fDisconnect) {
LogPrint(BCLog::NET, "Network not active, dropping peer=%d\n", pnode->GetId());
pnode->fDisconnect = true;
}
}
}
// Disconnect unused nodes
std::vector<CNode*> nodes_copy = m_nodes;
for (CNode* pnode : nodes_copy)
{
if (pnode->fDisconnect)
{
// remove from m_nodes
m_nodes.erase(remove(m_nodes.begin(), m_nodes.end(), pnode), m_nodes.end());
// Add to reconnection list if appropriate. We don't reconnect right here, because
// the creation of a connection is a blocking operation (up to several seconds),
// and we don't want to hold up the socket handler thread for that long.
if (pnode->m_transport->ShouldReconnectV1()) {
reconnections_to_add.push_back({
.addr_connect = pnode->addr,
.grant = std::move(pnode->grantOutbound),
.destination = pnode->m_dest,
.conn_type = pnode->m_conn_type,
.use_v2transport = false});
LogPrint(BCLog::NET, "retrying with v1 transport protocol for peer=%d\n", pnode->GetId());
}
// release outbound grant (if any)
pnode->grantOutbound.Release();
// close socket and cleanup
pnode->CloseSocketDisconnect();
// update connection count by network
if (pnode->IsManualOrFullOutboundConn()) --m_network_conn_counts[pnode->addr.GetNetwork()];
// hold in disconnected pool until all refs are released
pnode->Release();
m_nodes_disconnected.push_back(pnode);
}
}
}
{
// Delete disconnected nodes
std::list<CNode*> nodes_disconnected_copy = m_nodes_disconnected;
for (CNode* pnode : nodes_disconnected_copy)
{
// Destroy the object only after other threads have stopped using it.
if (pnode->GetRefCount() <= 0) {
m_nodes_disconnected.remove(pnode);
DeleteNode(pnode);
}
}
}
{
// Move entries from reconnections_to_add to m_reconnections.
LOCK(m_reconnections_mutex);
m_reconnections.splice(m_reconnections.end(), std::move(reconnections_to_add));
}
}
void CConnman::NotifyNumConnectionsChanged()
{
size_t nodes_size;
{
LOCK(m_nodes_mutex);
nodes_size = m_nodes.size();
}
if(nodes_size != nPrevNodeCount) {
nPrevNodeCount = nodes_size;
if (m_client_interface) {
m_client_interface->NotifyNumConnectionsChanged(nodes_size);
}
}
}
bool CConnman::ShouldRunInactivityChecks(const CNode& node, std::chrono::seconds now) const
{
return node.m_connected + m_peer_connect_timeout < now;
}
bool CConnman::InactivityCheck(const CNode& node) const
{
// Tests that see disconnects after using mocktime can start nodes with a
// large timeout. For example, -peertimeout=999999999.
const auto now{GetTime<std::chrono::seconds>()};
const auto last_send{node.m_last_send.load()};
const auto last_recv{node.m_last_recv.load()};
if (!ShouldRunInactivityChecks(node, now)) return false;
if (last_recv.count() == 0 || last_send.count() == 0) {
LogPrint(BCLog::NET, "socket no message in first %i seconds, %d %d peer=%d\n", count_seconds(m_peer_connect_timeout), last_recv.count() != 0, last_send.count() != 0, node.GetId());
return true;
}
if (now > last_send + TIMEOUT_INTERVAL) {
LogPrint(BCLog::NET, "socket sending timeout: %is peer=%d\n", count_seconds(now - last_send), node.GetId());
return true;
}
if (now > last_recv + TIMEOUT_INTERVAL) {
LogPrint(BCLog::NET, "socket receive timeout: %is peer=%d\n", count_seconds(now - last_recv), node.GetId());
return true;
}
if (!node.fSuccessfullyConnected) {
LogPrint(BCLog::NET, "version handshake timeout peer=%d\n", node.GetId());
return true;
}
return false;
}
Sock::EventsPerSock CConnman::GenerateWaitSockets(Span<CNode* const> nodes)
{
Sock::EventsPerSock events_per_sock;
for (const ListenSocket& hListenSocket : vhListenSocket) {
events_per_sock.emplace(hListenSocket.sock, Sock::Events{Sock::RECV});
}
for (CNode* pnode : nodes) {
bool select_recv = !pnode->fPauseRecv;
bool select_send;
{
LOCK(pnode->cs_vSend);
// Sending is possible if either there are bytes to send right now, or if there will be
// once a potential message from vSendMsg is handed to the transport. GetBytesToSend
// determines both of these in a single call.
const auto& [to_send, more, _msg_type] = pnode->m_transport->GetBytesToSend(!pnode->vSendMsg.empty());
select_send = !to_send.empty() || more;
}
if (!select_recv && !select_send) continue;
LOCK(pnode->m_sock_mutex);
if (pnode->m_sock) {
Sock::Event event = (select_send ? Sock::SEND : 0) | (select_recv ? Sock::RECV : 0);
events_per_sock.emplace(pnode->m_sock, Sock::Events{event});
}
}
return events_per_sock;
}
void CConnman::SocketHandler()
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
Sock::EventsPerSock events_per_sock;
{
const NodesSnapshot snap{*this, /*shuffle=*/false};
const auto timeout = std::chrono::milliseconds(SELECT_TIMEOUT_MILLISECONDS);
// Check for the readiness of the already connected sockets and the
// listening sockets in one call ("readiness" as in poll(2) or
// select(2)). If none are ready, wait for a short while and return
// empty sets.
events_per_sock = GenerateWaitSockets(snap.Nodes());
if (events_per_sock.empty() || !events_per_sock.begin()->first->WaitMany(timeout, events_per_sock)) {
interruptNet.sleep_for(timeout);
}
// Service (send/receive) each of the already connected nodes.
SocketHandlerConnected(snap.Nodes(), events_per_sock);
}
// Accept new connections from listening sockets.
SocketHandlerListening(events_per_sock);
}
void CConnman::SocketHandlerConnected(const std::vector<CNode*>& nodes,
const Sock::EventsPerSock& events_per_sock)
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
for (CNode* pnode : nodes) {
if (interruptNet)
return;
//
// Receive
//
bool recvSet = false;
bool sendSet = false;
bool errorSet = false;
{
LOCK(pnode->m_sock_mutex);
if (!pnode->m_sock) {
continue;
}
const auto it = events_per_sock.find(pnode->m_sock);
if (it != events_per_sock.end()) {
recvSet = it->second.occurred & Sock::RECV;
sendSet = it->second.occurred & Sock::SEND;
errorSet = it->second.occurred & Sock::ERR;
}
}
if (sendSet) {
// Send data
auto [bytes_sent, data_left] = WITH_LOCK(pnode->cs_vSend, return SocketSendData(*pnode));
if (bytes_sent) {
RecordBytesSent(bytes_sent);
// If both receiving and (non-optimistic) sending were possible, we first attempt
// sending. If that succeeds, but does not fully drain the send queue, do not
// attempt to receive. This avoids needlessly queueing data if the remote peer
// is slow at receiving data, by means of TCP flow control. We only do this when
// sending actually succeeded to make sure progress is always made; otherwise a
// deadlock would be possible when both sides have data to send, but neither is
// receiving.
if (data_left) recvSet = false;
}
}
if (recvSet || errorSet)
{
// typical socket buffer is 8K-64K
uint8_t pchBuf[0x10000];
int nBytes = 0;
{
LOCK(pnode->m_sock_mutex);
if (!pnode->m_sock) {
continue;
}
nBytes = pnode->m_sock->Recv(pchBuf, sizeof(pchBuf), MSG_DONTWAIT);
}
if (nBytes > 0)
{
bool notify = false;
if (!pnode->ReceiveMsgBytes({pchBuf, (size_t)nBytes}, notify)) {
pnode->CloseSocketDisconnect();
}
RecordBytesRecv(nBytes);
if (notify) {
pnode->MarkReceivedMsgsForProcessing();
WakeMessageHandler();
}
}
else if (nBytes == 0)
{
// socket closed gracefully
if (!pnode->fDisconnect) {
LogPrint(BCLog::NET, "socket closed for peer=%d\n", pnode->GetId());
}
pnode->CloseSocketDisconnect();
}
else if (nBytes < 0)
{
// error
int nErr = WSAGetLastError();
if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS)
{
if (!pnode->fDisconnect) {
LogPrint(BCLog::NET, "socket recv error for peer=%d: %s\n", pnode->GetId(), NetworkErrorString(nErr));
}
pnode->CloseSocketDisconnect();
}
}
}
if (InactivityCheck(*pnode)) pnode->fDisconnect = true;
}
}
void CConnman::SocketHandlerListening(const Sock::EventsPerSock& events_per_sock)
{
for (const ListenSocket& listen_socket : vhListenSocket) {
if (interruptNet) {
return;
}
const auto it = events_per_sock.find(listen_socket.sock);
if (it != events_per_sock.end() && it->second.occurred & Sock::RECV) {
AcceptConnection(listen_socket);
}
}
}
void CConnman::ThreadSocketHandler()
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
while (!interruptNet)
{
DisconnectNodes();
NotifyNumConnectionsChanged();
SocketHandler();
}
}
void CConnman::WakeMessageHandler()
{
{
LOCK(mutexMsgProc);
fMsgProcWake = true;
}
condMsgProc.notify_one();
}
void CConnman::ThreadDNSAddressSeed()
{
constexpr int TARGET_OUTBOUND_CONNECTIONS = 2;
int outbound_connection_count = 0;
if (gArgs.IsArgSet("-seednode")) {
auto start = NodeClock::now();
constexpr std::chrono::seconds SEEDNODE_TIMEOUT = 30s;
LogPrintf("-seednode enabled. Trying the provided seeds for %d seconds before defaulting to the dnsseeds.\n", SEEDNODE_TIMEOUT.count());
while (!interruptNet) {
if (!interruptNet.sleep_for(std::chrono::milliseconds(500)))
return;
// Abort if we have spent enough time without reaching our target.
// Giving seed nodes 30 seconds so this does not become a race against fixedseeds (which triggers after 1 min)
if (NodeClock::now() > start + SEEDNODE_TIMEOUT) {
LogPrintf("Couldn't connect to enough peers via seed nodes. Handing fetch logic to the DNS seeds.\n");
break;
}
outbound_connection_count = GetFullOutboundConnCount();
if (outbound_connection_count >= TARGET_OUTBOUND_CONNECTIONS) {
LogPrintf("P2P peers available. Finished fetching data from seed nodes.\n");
break;
}
}
}
FastRandomContext rng;
std::vector<std::string> seeds = m_params.DNSSeeds();
Shuffle(seeds.begin(), seeds.end(), rng);
int seeds_right_now = 0; // Number of seeds left before testing if we have enough connections
if (gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED)) {
// When -forcednsseed is provided, query all.
seeds_right_now = seeds.size();
} else if (addrman.Size() == 0) {
// If we have no known peers, query all.
// This will occur on the first run, or if peers.dat has been
// deleted.
seeds_right_now = seeds.size();
}
// Proceed with dnsseeds if seednodes hasn't reached the target or if forcednsseed is set
if (outbound_connection_count < TARGET_OUTBOUND_CONNECTIONS || seeds_right_now) {
// goal: only query DNS seed if address need is acute
// * If we have a reasonable number of peers in addrman, spend
// some time trying them first. This improves user privacy by
// creating fewer identifying DNS requests, reduces trust by
// giving seeds less influence on the network topology, and
// reduces traffic to the seeds.
// * When querying DNS seeds query a few at once, this ensures
// that we don't give DNS seeds the ability to eclipse nodes
// that query them.
// * If we continue having problems, eventually query all the
// DNS seeds, and if that fails too, also try the fixed seeds.
// (done in ThreadOpenConnections)
int found = 0;
const std::chrono::seconds seeds_wait_time = (addrman.Size() >= DNSSEEDS_DELAY_PEER_THRESHOLD ? DNSSEEDS_DELAY_MANY_PEERS : DNSSEEDS_DELAY_FEW_PEERS);
for (const std::string& seed : seeds) {
if (seeds_right_now == 0) {
seeds_right_now += DNSSEEDS_TO_QUERY_AT_ONCE;
if (addrman.Size() > 0) {
LogPrintf("Waiting %d seconds before querying DNS seeds.\n", seeds_wait_time.count());
std::chrono::seconds to_wait = seeds_wait_time;
while (to_wait.count() > 0) {
// if sleeping for the MANY_PEERS interval, wake up
// early to see if we have enough peers and can stop
// this thread entirely freeing up its resources
std::chrono::seconds w = std::min(DNSSEEDS_DELAY_FEW_PEERS, to_wait);
if (!interruptNet.sleep_for(w)) return;
to_wait -= w;
if (GetFullOutboundConnCount() >= TARGET_OUTBOUND_CONNECTIONS) {
if (found > 0) {
LogPrintf("%d addresses found from DNS seeds\n", found);
LogPrintf("P2P peers available. Finished DNS seeding.\n");
} else {
LogPrintf("P2P peers available. Skipped DNS seeding.\n");
}
return;
}
}
}
}
if (interruptNet) return;
// hold off on querying seeds if P2P network deactivated
if (!fNetworkActive) {
LogPrintf("Waiting for network to be reactivated before querying DNS seeds.\n");
do {
if (!interruptNet.sleep_for(std::chrono::seconds{1})) return;
} while (!fNetworkActive);
}
LogPrintf("Loading addresses from DNS seed %s\n", seed);
// If -proxy is in use, we make an ADDR_FETCH connection to the DNS resolved peer address
// for the base dns seed domain in chainparams
if (HaveNameProxy()) {
AddAddrFetch(seed);
} else {
std::vector<CAddress> vAdd;
constexpr ServiceFlags requiredServiceBits{SeedsServiceFlags()};
std::string host = strprintf("x%x.%s", requiredServiceBits, seed);
CNetAddr resolveSource;
if (!resolveSource.SetInternal(host)) {
continue;
}
// Limit number of IPs learned from a single DNS seed. This limit exists to prevent the results from
// one DNS seed from dominating AddrMan. Note that the number of results from a UDP DNS query is
// bounded to 33 already, but it is possible for it to use TCP where a larger number of results can be
// returned.
unsigned int nMaxIPs = 32;
const auto addresses{LookupHost(host, nMaxIPs, true)};
if (!addresses.empty()) {
for (const CNetAddr& ip : addresses) {
CAddress addr = CAddress(CService(ip, m_params.GetDefaultPort()), requiredServiceBits);
addr.nTime = rng.rand_uniform_delay(Now<NodeSeconds>() - 3 * 24h, -4 * 24h); // use a random age between 3 and 7 days old
vAdd.push_back(addr);
found++;
}
addrman.Add(vAdd, resolveSource);
} else {
// If the seed does not support a subdomain with our desired service bits,
// we make an ADDR_FETCH connection to the DNS resolved peer address for the
// base dns seed domain in chainparams
AddAddrFetch(seed);
}
}
--seeds_right_now;
}
LogPrintf("%d addresses found from DNS seeds\n", found);
} else {
LogPrintf("Skipping DNS seeds. Enough peers have been found\n");
}
}
void CConnman::DumpAddresses()
{
const auto start{SteadyClock::now()};
DumpPeerAddresses(::gArgs, addrman);
LogPrint(BCLog::NET, "Flushed %d addresses to peers.dat %dms\n",
addrman.Size(), Ticks<std::chrono::milliseconds>(SteadyClock::now() - start));
}
void CConnman::ProcessAddrFetch()
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
std::string strDest;
{
LOCK(m_addr_fetches_mutex);
if (m_addr_fetches.empty())
return;
strDest = m_addr_fetches.front();
m_addr_fetches.pop_front();
}
// Attempt v2 connection if we support v2 - we'll reconnect with v1 if our
// peer doesn't support it or immediately disconnects us for another reason.
const bool use_v2transport(GetLocalServices() & NODE_P2P_V2);
CAddress addr;
CSemaphoreGrant grant(*semOutbound, /*fTry=*/true);
if (grant) {
OpenNetworkConnection(addr, false, std::move(grant), strDest.c_str(), ConnectionType::ADDR_FETCH, use_v2transport);
}
}
bool CConnman::GetTryNewOutboundPeer() const
{
return m_try_another_outbound_peer;
}
void CConnman::SetTryNewOutboundPeer(bool flag)
{
m_try_another_outbound_peer = flag;
LogPrint(BCLog::NET, "setting try another outbound peer=%s\n", flag ? "true" : "false");
}
void CConnman::StartExtraBlockRelayPeers()
{
LogPrint(BCLog::NET, "enabling extra block-relay-only peers\n");
m_start_extra_block_relay_peers = true;
}
// Return the number of outbound connections that are full relay (not blocks only)
int CConnman::GetFullOutboundConnCount() const
{
int nRelevant = 0;
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->fSuccessfullyConnected && pnode->IsFullOutboundConn()) ++nRelevant;
}
}
return nRelevant;
}
// Return the number of peers we have over our outbound connection limit
// Exclude peers that are marked for disconnect, or are going to be
// disconnected soon (eg ADDR_FETCH and FEELER)
// Also exclude peers that haven't finished initial connection handshake yet
// (so that we don't decide we're over our desired connection limit, and then
// evict some peer that has finished the handshake)
int CConnman::GetExtraFullOutboundCount() const
{
int full_outbound_peers = 0;
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->fSuccessfullyConnected && !pnode->fDisconnect && pnode->IsFullOutboundConn()) {
++full_outbound_peers;
}
}
}
return std::max(full_outbound_peers - m_max_outbound_full_relay, 0);
}
int CConnman::GetExtraBlockRelayCount() const
{
int block_relay_peers = 0;
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->fSuccessfullyConnected && !pnode->fDisconnect && pnode->IsBlockOnlyConn()) {
++block_relay_peers;
}
}
}
return std::max(block_relay_peers - m_max_outbound_block_relay, 0);
}
std::unordered_set<Network> CConnman::GetReachableEmptyNetworks() const
{
std::unordered_set<Network> networks{};
for (int n = 0; n < NET_MAX; n++) {
enum Network net = (enum Network)n;
if (net == NET_UNROUTABLE || net == NET_INTERNAL) continue;
if (g_reachable_nets.Contains(net) && addrman.Size(net, std::nullopt) == 0) {
networks.insert(net);
}
}
return networks;
}
bool CConnman::MultipleManualOrFullOutboundConns(Network net) const
{
AssertLockHeld(m_nodes_mutex);
return m_network_conn_counts[net] > 1;
}
bool CConnman::MaybePickPreferredNetwork(std::optional<Network>& network)
{
std::array<Network, 5> nets{NET_IPV4, NET_IPV6, NET_ONION, NET_I2P, NET_CJDNS};
Shuffle(nets.begin(), nets.end(), FastRandomContext());
LOCK(m_nodes_mutex);
for (const auto net : nets) {
if (g_reachable_nets.Contains(net) && m_network_conn_counts[net] == 0 && addrman.Size(net) != 0) {
network = net;
return true;
}
}
return false;
}
void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
AssertLockNotHeld(m_reconnections_mutex);
FastRandomContext rng;
// Connect to specific addresses
if (!connect.empty())
{
// Attempt v2 connection if we support v2 - we'll reconnect with v1 if our
// peer doesn't support it or immediately disconnects us for another reason.
const bool use_v2transport(GetLocalServices() & NODE_P2P_V2);
for (int64_t nLoop = 0;; nLoop++)
{
for (const std::string& strAddr : connect)
{
CAddress addr(CService(), NODE_NONE);
OpenNetworkConnection(addr, false, {}, strAddr.c_str(), ConnectionType::MANUAL, /*use_v2transport=*/use_v2transport);
for (int i = 0; i < 10 && i < nLoop; i++)
{
if (!interruptNet.sleep_for(std::chrono::milliseconds(500)))
return;
}
}
if (!interruptNet.sleep_for(std::chrono::milliseconds(500)))
return;
PerformReconnections();
}
}
// Initiate network connections
auto start = GetTime<std::chrono::microseconds>();
// Minimum time before next feeler connection (in microseconds).
auto next_feeler = GetExponentialRand(start, FEELER_INTERVAL);
auto next_extra_block_relay = GetExponentialRand(start, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
auto next_extra_network_peer{GetExponentialRand(start, EXTRA_NETWORK_PEER_INTERVAL)};
const bool dnsseed = gArgs.GetBoolArg("-dnsseed", DEFAULT_DNSSEED);
bool add_fixed_seeds = gArgs.GetBoolArg("-fixedseeds", DEFAULT_FIXEDSEEDS);
const bool use_seednodes{gArgs.IsArgSet("-seednode")};
if (!add_fixed_seeds) {
LogPrintf("Fixed seeds are disabled\n");
}
while (!interruptNet)
{
ProcessAddrFetch();
if (!interruptNet.sleep_for(std::chrono::milliseconds(500)))
return;
PerformReconnections();
CSemaphoreGrant grant(*semOutbound);
if (interruptNet)
return;
const std::unordered_set<Network> fixed_seed_networks{GetReachableEmptyNetworks()};
if (add_fixed_seeds && !fixed_seed_networks.empty()) {
// When the node starts with an empty peers.dat, there are a few other sources of peers before
// we fallback on to fixed seeds: -dnsseed, -seednode, -addnode
// If none of those are available, we fallback on to fixed seeds immediately, else we allow
// 60 seconds for any of those sources to populate addrman.
bool add_fixed_seeds_now = false;
// It is cheapest to check if enough time has passed first.
if (GetTime<std::chrono::seconds>() > start + std::chrono::minutes{1}) {
add_fixed_seeds_now = true;
LogPrintf("Adding fixed seeds as 60 seconds have passed and addrman is empty for at least one reachable network\n");
}
// Perform cheap checks before locking a mutex.
else if (!dnsseed && !use_seednodes) {
LOCK(m_added_nodes_mutex);
if (m_added_node_params.empty()) {
add_fixed_seeds_now = true;
LogPrintf("Adding fixed seeds as -dnsseed=0 (or IPv4/IPv6 connections are disabled via -onlynet) and neither -addnode nor -seednode are provided\n");
}
}
if (add_fixed_seeds_now) {
std::vector<CAddress> seed_addrs{ConvertSeeds(m_params.FixedSeeds())};
// We will not make outgoing connections to peers that are unreachable
// (e.g. because of -onlynet configuration).
// Therefore, we do not add them to addrman in the first place.
// In case previously unreachable networks become reachable
// (e.g. in case of -onlynet changes by the user), fixed seeds will
// be loaded only for networks for which we have no addresses.
seed_addrs.erase(std::remove_if(seed_addrs.begin(), seed_addrs.end(),
[&fixed_seed_networks](const CAddress& addr) { return fixed_seed_networks.count(addr.GetNetwork()) == 0; }),
seed_addrs.end());
CNetAddr local;
local.SetInternal("fixedseeds");
addrman.Add(seed_addrs, local);
add_fixed_seeds = false;
LogPrintf("Added %d fixed seeds from reachable networks.\n", seed_addrs.size());
}
}
//
// Choose an address to connect to based on most recently seen
//
CAddress addrConnect;
// Only connect out to one peer per ipv4/ipv6 network group (/16 for IPv4).
int nOutboundFullRelay = 0;
int nOutboundBlockRelay = 0;
int outbound_privacy_network_peers = 0;
std::set<std::vector<unsigned char>> outbound_ipv46_peer_netgroups;
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->IsFullOutboundConn()) nOutboundFullRelay++;
if (pnode->IsBlockOnlyConn()) nOutboundBlockRelay++;
// Make sure our persistent outbound slots to ipv4/ipv6 peers belong to different netgroups.
switch (pnode->m_conn_type) {
// We currently don't take inbound connections into account. Since they are
// free to make, an attacker could make them to prevent us from connecting to
// certain peers.
case ConnectionType::INBOUND:
// Short-lived outbound connections should not affect how we select outbound
// peers from addrman.
case ConnectionType::ADDR_FETCH:
case ConnectionType::FEELER:
break;
case ConnectionType::MANUAL:
case ConnectionType::OUTBOUND_FULL_RELAY:
case ConnectionType::BLOCK_RELAY:
const CAddress address{pnode->addr};
if (address.IsTor() || address.IsI2P() || address.IsCJDNS()) {
// Since our addrman-groups for these networks are
// random, without relation to the route we
// take to connect to these peers or to the
// difficulty in obtaining addresses with diverse
// groups, we don't worry about diversity with
// respect to our addrman groups when connecting to
// these networks.
++outbound_privacy_network_peers;
} else {
outbound_ipv46_peer_netgroups.insert(m_netgroupman.GetGroup(address));
}
} // no default case, so the compiler can warn about missing cases
}
}
ConnectionType conn_type = ConnectionType::OUTBOUND_FULL_RELAY;
auto now = GetTime<std::chrono::microseconds>();
bool anchor = false;
bool fFeeler = false;
std::optional<Network> preferred_net;
// Determine what type of connection to open. Opening
// BLOCK_RELAY connections to addresses from anchors.dat gets the highest
// priority. Then we open OUTBOUND_FULL_RELAY priority until we
// meet our full-relay capacity. Then we open BLOCK_RELAY connection
// until we hit our block-relay-only peer limit.
// GetTryNewOutboundPeer() gets set when a stale tip is detected, so we
// try opening an additional OUTBOUND_FULL_RELAY connection. If none of
// these conditions are met, check to see if it's time to try an extra
// block-relay-only peer (to confirm our tip is current, see below) or the next_feeler
// timer to decide if we should open a FEELER.
if (!m_anchors.empty() && (nOutboundBlockRelay < m_max_outbound_block_relay)) {
conn_type = ConnectionType::BLOCK_RELAY;
anchor = true;
} else if (nOutboundFullRelay < m_max_outbound_full_relay) {
// OUTBOUND_FULL_RELAY
} else if (nOutboundBlockRelay < m_max_outbound_block_relay) {
conn_type = ConnectionType::BLOCK_RELAY;
} else if (GetTryNewOutboundPeer()) {
// OUTBOUND_FULL_RELAY
} else if (now > next_extra_block_relay && m_start_extra_block_relay_peers) {
// Periodically connect to a peer (using regular outbound selection
// methodology from addrman) and stay connected long enough to sync
// headers, but not much else.
//
// Then disconnect the peer, if we haven't learned anything new.
//
// The idea is to make eclipse attacks very difficult to pull off,
// because every few minutes we're finding a new peer to learn headers
// from.
//
// This is similar to the logic for trying extra outbound (full-relay)
// peers, except:
// - we do this all the time on an exponential timer, rather than just when
// our tip is stale
// - we potentially disconnect our next-youngest block-relay-only peer, if our
// newest block-relay-only peer delivers a block more recently.
// See the eviction logic in net_processing.cpp.
//
// Because we can promote these connections to block-relay-only
// connections, they do not get their own ConnectionType enum
// (similar to how we deal with extra outbound peers).
next_extra_block_relay = GetExponentialRand(now, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
conn_type = ConnectionType::BLOCK_RELAY;
} else if (now > next_feeler) {
next_feeler = GetExponentialRand(now, FEELER_INTERVAL);
conn_type = ConnectionType::FEELER;
fFeeler = true;
} else if (nOutboundFullRelay == m_max_outbound_full_relay &&
m_max_outbound_full_relay == MAX_OUTBOUND_FULL_RELAY_CONNECTIONS &&
now > next_extra_network_peer &&
MaybePickPreferredNetwork(preferred_net)) {
// Full outbound connection management: Attempt to get at least one
// outbound peer from each reachable network by making extra connections
// and then protecting "only" peers from a network during outbound eviction.
// This is not attempted if the user changed -maxconnections to a value
// so low that less than MAX_OUTBOUND_FULL_RELAY_CONNECTIONS are made,
// to prevent interactions with otherwise protected outbound peers.
next_extra_network_peer = GetExponentialRand(now, EXTRA_NETWORK_PEER_INTERVAL);
} else {
// skip to next iteration of while loop
continue;
}
addrman.ResolveCollisions();
const auto current_time{NodeClock::now()};
int nTries = 0;
while (!interruptNet)
{
if (anchor && !m_anchors.empty()) {
const CAddress addr = m_anchors.back();
m_anchors.pop_back();
if (!addr.IsValid() || IsLocal(addr) || !g_reachable_nets.Contains(addr) ||
!m_msgproc->HasAllDesirableServiceFlags(addr.nServices) ||
outbound_ipv46_peer_netgroups.count(m_netgroupman.GetGroup(addr))) continue;
addrConnect = addr;
LogPrint(BCLog::NET, "Trying to make an anchor connection to %s\n", addrConnect.ToStringAddrPort());
break;
}
// If we didn't find an appropriate destination after trying 100 addresses fetched from addrman,
// stop this loop, and let the outer loop run again (which sleeps, adds seed nodes, recalculates
// already-connected network ranges, ...) before trying new addrman addresses.
nTries++;
if (nTries > 100)
break;
CAddress addr;
NodeSeconds addr_last_try{0s};
if (fFeeler) {
// First, try to get a tried table collision address. This returns
// an empty (invalid) address if there are no collisions to try.
std::tie(addr, addr_last_try) = addrman.SelectTriedCollision();
if (!addr.IsValid()) {
// No tried table collisions. Select a new table address
// for our feeler.
std::tie(addr, addr_last_try) = addrman.Select(true);
} else if (AlreadyConnectedToAddress(addr)) {
// If test-before-evict logic would have us connect to a
// peer that we're already connected to, just mark that
// address as Good(). We won't be able to initiate the
// connection anyway, so this avoids inadvertently evicting
// a currently-connected peer.
addrman.Good(addr);
// Select a new table address for our feeler instead.
std::tie(addr, addr_last_try) = addrman.Select(true);
}
} else {
// Not a feeler
// If preferred_net has a value set, pick an extra outbound
// peer from that network. The eviction logic in net_processing
// ensures that a peer from another network will be evicted.
std::tie(addr, addr_last_try) = addrman.Select(false, preferred_net);
}
// Require outbound IPv4/IPv6 connections, other than feelers, to be to distinct network groups
if (!fFeeler && outbound_ipv46_peer_netgroups.count(m_netgroupman.GetGroup(addr))) {
continue;
}
// if we selected an invalid or local address, restart
if (!addr.IsValid() || IsLocal(addr)) {
break;
}
if (!g_reachable_nets.Contains(addr)) {
continue;
}
// only consider very recently tried nodes after 30 failed attempts
if (current_time - addr_last_try < 10min && nTries < 30) {
continue;
}
// for non-feelers, require all the services we'll want,
// for feelers, only require they be a full node (only because most
// SPV clients don't have a good address DB available)
if (!fFeeler && !m_msgproc->HasAllDesirableServiceFlags(addr.nServices)) {
continue;
} else if (fFeeler && !MayHaveUsefulAddressDB(addr.nServices)) {
continue;
}
// Do not connect to bad ports, unless 50 invalid addresses have been selected already.
if (nTries < 50 && (addr.IsIPv4() || addr.IsIPv6()) && IsBadPort(addr.GetPort())) {
continue;
}
// Do not make automatic outbound connections to addnode peers, to
// not use our limited outbound slots for them and to ensure
// addnode connections benefit from their intended protections.
if (AddedNodesContain(addr)) {
LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "Not making automatic %s%s connection to %s peer selected for manual (addnode) connection%s\n",
preferred_net.has_value() ? "network-specific " : "",
ConnectionTypeAsString(conn_type), GetNetworkName(addr.GetNetwork()),
fLogIPs ? strprintf(": %s", addr.ToStringAddrPort()) : "");
continue;
}
addrConnect = addr;
break;
}
if (addrConnect.IsValid()) {
if (fFeeler) {
// Add small amount of random noise before connection to avoid synchronization.
if (!interruptNet.sleep_for(rng.rand_uniform_duration<CThreadInterrupt::Clock>(FEELER_SLEEP_WINDOW))) {
return;
}
LogPrint(BCLog::NET, "Making feeler connection to %s\n", addrConnect.ToStringAddrPort());
}
if (preferred_net != std::nullopt) LogPrint(BCLog::NET, "Making network specific connection to %s on %s.\n", addrConnect.ToStringAddrPort(), GetNetworkName(preferred_net.value()));
// Record addrman failure attempts when node has at least 2 persistent outbound connections to peers with
// different netgroups in ipv4/ipv6 networks + all peers in Tor/I2P/CJDNS networks.
// Don't record addrman failure attempts when node is offline. This can be identified since all local
// network connections (if any) belong in the same netgroup, and the size of `outbound_ipv46_peer_netgroups` would only be 1.
const bool count_failures{((int)outbound_ipv46_peer_netgroups.size() + outbound_privacy_network_peers) >= std::min(m_max_automatic_connections - 1, 2)};
// Use BIP324 transport when both us and them have NODE_V2_P2P set.
const bool use_v2transport(addrConnect.nServices & GetLocalServices() & NODE_P2P_V2);
OpenNetworkConnection(addrConnect, count_failures, std::move(grant), /*strDest=*/nullptr, conn_type, use_v2transport);
}
}
}
std::vector<CAddress> CConnman::GetCurrentBlockRelayOnlyConns() const
{
std::vector<CAddress> ret;
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->IsBlockOnlyConn()) {
ret.push_back(pnode->addr);
}
}
return ret;
}
std::vector<AddedNodeInfo> CConnman::GetAddedNodeInfo(bool include_connected) const
{
std::vector<AddedNodeInfo> ret;
std::list<AddedNodeParams> lAddresses(0);
{
LOCK(m_added_nodes_mutex);
ret.reserve(m_added_node_params.size());
std::copy(m_added_node_params.cbegin(), m_added_node_params.cend(), std::back_inserter(lAddresses));
}
// Build a map of all already connected addresses (by IP:port and by name) to inbound/outbound and resolved CService
std::map<CService, bool> mapConnected;
std::map<std::string, std::pair<bool, CService>> mapConnectedByName;
{
LOCK(m_nodes_mutex);
for (const CNode* pnode : m_nodes) {
if (pnode->addr.IsValid()) {
mapConnected[pnode->addr] = pnode->IsInboundConn();
}
std::string addrName{pnode->m_addr_name};
if (!addrName.empty()) {
mapConnectedByName[std::move(addrName)] = std::make_pair(pnode->IsInboundConn(), static_cast<const CService&>(pnode->addr));
}
}
}
for (const auto& addr : lAddresses) {
CService service(LookupNumeric(addr.m_added_node, GetDefaultPort(addr.m_added_node)));
AddedNodeInfo addedNode{addr, CService(), false, false};
if (service.IsValid()) {
// strAddNode is an IP:port
auto it = mapConnected.find(service);
if (it != mapConnected.end()) {
if (!include_connected) {
continue;
}
addedNode.resolvedAddress = service;
addedNode.fConnected = true;
addedNode.fInbound = it->second;
}
} else {
// strAddNode is a name
auto it = mapConnectedByName.find(addr.m_added_node);
if (it != mapConnectedByName.end()) {
if (!include_connected) {
continue;
}
addedNode.resolvedAddress = it->second.second;
addedNode.fConnected = true;
addedNode.fInbound = it->second.first;
}
}
ret.emplace_back(std::move(addedNode));
}
return ret;
}
void CConnman::ThreadOpenAddedConnections()
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
AssertLockNotHeld(m_reconnections_mutex);
while (true)
{
CSemaphoreGrant grant(*semAddnode);
std::vector<AddedNodeInfo> vInfo = GetAddedNodeInfo(/*include_connected=*/false);
bool tried = false;
for (const AddedNodeInfo& info : vInfo) {
if (!grant) {
// If we've used up our semaphore and need a new one, let's not wait here since while we are waiting
// the addednodeinfo state might change.
break;
}
tried = true;
CAddress addr(CService(), NODE_NONE);
OpenNetworkConnection(addr, false, std::move(grant), info.m_params.m_added_node.c_str(), ConnectionType::MANUAL, info.m_params.m_use_v2transport);
if (!interruptNet.sleep_for(std::chrono::milliseconds(500))) return;
grant = CSemaphoreGrant(*semAddnode, /*fTry=*/true);
}
// See if any reconnections are desired.
PerformReconnections();
// Retry every 60 seconds if a connection was attempted, otherwise two seconds
if (!interruptNet.sleep_for(std::chrono::seconds(tried ? 60 : 2)))
return;
}
}
// if successful, this moves the passed grant to the constructed node
void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant&& grant_outbound, const char *pszDest, ConnectionType conn_type, bool use_v2transport)
{
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
assert(conn_type != ConnectionType::INBOUND);
//
// Initiate outbound network connection
//
if (interruptNet) {
return;
}
if (!fNetworkActive) {
return;
}
if (!pszDest) {
bool banned_or_discouraged = m_banman && (m_banman->IsDiscouraged(addrConnect) || m_banman->IsBanned(addrConnect));
if (IsLocal(addrConnect) || banned_or_discouraged || AlreadyConnectedToAddress(addrConnect)) {
return;
}
} else if (FindNode(std::string(pszDest)))
return;
CNode* pnode = ConnectNode(addrConnect, pszDest, fCountFailure, conn_type, use_v2transport);
if (!pnode)
return;
pnode->grantOutbound = std::move(grant_outbound);
m_msgproc->InitializeNode(*pnode, nLocalServices);
{
LOCK(m_nodes_mutex);
m_nodes.push_back(pnode);
// update connection count by network
if (pnode->IsManualOrFullOutboundConn()) ++m_network_conn_counts[pnode->addr.GetNetwork()];
}
}
Mutex NetEventsInterface::g_msgproc_mutex;
void CConnman::ThreadMessageHandler()
{
LOCK(NetEventsInterface::g_msgproc_mutex);
while (!flagInterruptMsgProc)
{
bool fMoreWork = false;
{
// Randomize the order in which we process messages from/to our peers.
// This prevents attacks in which an attacker exploits having multiple
// consecutive connections in the m_nodes list.
const NodesSnapshot snap{*this, /*shuffle=*/true};
for (CNode* pnode : snap.Nodes()) {
if (pnode->fDisconnect)
continue;
// Receive messages
bool fMoreNodeWork = m_msgproc->ProcessMessages(pnode, flagInterruptMsgProc);
fMoreWork |= (fMoreNodeWork && !pnode->fPauseSend);
if (flagInterruptMsgProc)
return;
// Send messages
m_msgproc->SendMessages(pnode);
if (flagInterruptMsgProc)
return;
}
}
WAIT_LOCK(mutexMsgProc, lock);
if (!fMoreWork) {
condMsgProc.wait_until(lock, std::chrono::steady_clock::now() + std::chrono::milliseconds(100), [this]() EXCLUSIVE_LOCKS_REQUIRED(mutexMsgProc) { return fMsgProcWake; });
}
fMsgProcWake = false;
}
}
void CConnman::ThreadI2PAcceptIncoming()
{
static constexpr auto err_wait_begin = 1s;
static constexpr auto err_wait_cap = 5min;
auto err_wait = err_wait_begin;
bool advertising_listen_addr = false;
i2p::Connection conn;
auto SleepOnFailure = [&]() {
interruptNet.sleep_for(err_wait);
if (err_wait < err_wait_cap) {
err_wait += 1s;
}
};
while (!interruptNet) {
if (!m_i2p_sam_session->Listen(conn)) {
if (advertising_listen_addr && conn.me.IsValid()) {
RemoveLocal(conn.me);
advertising_listen_addr = false;
}
SleepOnFailure();
continue;
}
if (!advertising_listen_addr) {
AddLocal(conn.me, LOCAL_MANUAL);
advertising_listen_addr = true;
}
if (!m_i2p_sam_session->Accept(conn)) {
SleepOnFailure();
continue;
}
CreateNodeFromAcceptedSocket(std::move(conn.sock), NetPermissionFlags::None,
CAddress{conn.me, NODE_NONE}, CAddress{conn.peer, NODE_NONE});
err_wait = err_wait_begin;
}
}
bool CConnman::BindListenPort(const CService& addrBind, bilingual_str& strError, NetPermissionFlags permissions)
{
int nOne = 1;
// Create socket for listening for incoming connections
struct sockaddr_storage sockaddr;
socklen_t len = sizeof(sockaddr);
if (!addrBind.GetSockAddr((struct sockaddr*)&sockaddr, &len))
{
strError = strprintf(Untranslated("Bind address family for %s not supported"), addrBind.ToStringAddrPort());
LogPrintLevel(BCLog::NET, BCLog::Level::Error, "%s\n", strError.original);
return false;
}
std::unique_ptr<Sock> sock = CreateSock(addrBind.GetSAFamily());
if (!sock) {
strError = strprintf(Untranslated("Couldn't open socket for incoming connections (socket returned error %s)"), NetworkErrorString(WSAGetLastError()));
LogPrintLevel(BCLog::NET, BCLog::Level::Error, "%s\n", strError.original);
return false;
}
// Allow binding if the port is still in TIME_WAIT state after
// the program was closed and restarted.
if (sock->SetSockOpt(SOL_SOCKET, SO_REUSEADDR, (sockopt_arg_type)&nOne, sizeof(int)) == SOCKET_ERROR) {
strError = strprintf(Untranslated("Error setting SO_REUSEADDR on socket: %s, continuing anyway"), NetworkErrorString(WSAGetLastError()));
LogPrintf("%s\n", strError.original);
}
// some systems don't have IPV6_V6ONLY but are always v6only; others do have the option
// and enable it by default or not. Try to enable it, if possible.
if (addrBind.IsIPv6()) {
#ifdef IPV6_V6ONLY
if (sock->SetSockOpt(IPPROTO_IPV6, IPV6_V6ONLY, (sockopt_arg_type)&nOne, sizeof(int)) == SOCKET_ERROR) {
strError = strprintf(Untranslated("Error setting IPV6_V6ONLY on socket: %s, continuing anyway"), NetworkErrorString(WSAGetLastError()));
LogPrintf("%s\n", strError.original);
}
#endif
#ifdef WIN32
int nProtLevel = PROTECTION_LEVEL_UNRESTRICTED;
if (sock->SetSockOpt(IPPROTO_IPV6, IPV6_PROTECTION_LEVEL, (const char*)&nProtLevel, sizeof(int)) == SOCKET_ERROR) {
strError = strprintf(Untranslated("Error setting IPV6_PROTECTION_LEVEL on socket: %s, continuing anyway"), NetworkErrorString(WSAGetLastError()));
LogPrintf("%s\n", strError.original);
}
#endif
}
if (sock->Bind(reinterpret_cast<struct sockaddr*>(&sockaddr), len) == SOCKET_ERROR) {
int nErr = WSAGetLastError();
if (nErr == WSAEADDRINUSE)
strError = strprintf(_("Unable to bind to %s on this computer. %s is probably already running."), addrBind.ToStringAddrPort(), PACKAGE_NAME);
else
strError = strprintf(_("Unable to bind to %s on this computer (bind returned error %s)"), addrBind.ToStringAddrPort(), NetworkErrorString(nErr));
LogPrintLevel(BCLog::NET, BCLog::Level::Error, "%s\n", strError.original);
return false;
}
LogPrintf("Bound to %s\n", addrBind.ToStringAddrPort());
// Listen for incoming connections
if (sock->Listen(SOMAXCONN) == SOCKET_ERROR)
{
strError = strprintf(_("Listening for incoming connections failed (listen returned error %s)"), NetworkErrorString(WSAGetLastError()));
LogPrintLevel(BCLog::NET, BCLog::Level::Error, "%s\n", strError.original);
return false;
}
vhListenSocket.emplace_back(std::move(sock), permissions);
return true;
}
void Discover()
{
if (!fDiscover)
return;
#ifdef WIN32
// Get local host IP
char pszHostName[256] = "";
if (gethostname(pszHostName, sizeof(pszHostName)) != SOCKET_ERROR)
{
const std::vector<CNetAddr> addresses{LookupHost(pszHostName, 0, true)};
for (const CNetAddr& addr : addresses)
{
if (AddLocal(addr, LOCAL_IF))
LogPrintf("%s: %s - %s\n", __func__, pszHostName, addr.ToStringAddr());
}
}
#elif (HAVE_DECL_GETIFADDRS && HAVE_DECL_FREEIFADDRS)
// Get local host ip
struct ifaddrs* myaddrs;
if (getifaddrs(&myaddrs) == 0)
{
for (struct ifaddrs* ifa = myaddrs; ifa != nullptr; ifa = ifa->ifa_next)
{
if (ifa->ifa_addr == nullptr) continue;
if ((ifa->ifa_flags & IFF_UP) == 0) continue;
if (strcmp(ifa->ifa_name, "lo") == 0) continue;
if (strcmp(ifa->ifa_name, "lo0") == 0) continue;
if (ifa->ifa_addr->sa_family == AF_INET)
{
struct sockaddr_in* s4 = (struct sockaddr_in*)(ifa->ifa_addr);
CNetAddr addr(s4->sin_addr);
if (AddLocal(addr, LOCAL_IF))
LogPrintf("%s: IPv4 %s: %s\n", __func__, ifa->ifa_name, addr.ToStringAddr());
}
else if (ifa->ifa_addr->sa_family == AF_INET6)
{
struct sockaddr_in6* s6 = (struct sockaddr_in6*)(ifa->ifa_addr);
CNetAddr addr(s6->sin6_addr);
if (AddLocal(addr, LOCAL_IF))
LogPrintf("%s: IPv6 %s: %s\n", __func__, ifa->ifa_name, addr.ToStringAddr());
}
}
freeifaddrs(myaddrs);
}
#endif
}
void CConnman::SetNetworkActive(bool active)
{
LogPrintf("%s: %s\n", __func__, active);
if (fNetworkActive == active) {
return;
}
fNetworkActive = active;
if (m_client_interface) {
m_client_interface->NotifyNetworkActiveChanged(fNetworkActive);
}
}
CConnman::CConnman(uint64_t nSeed0In, uint64_t nSeed1In, AddrMan& addrman_in,
const NetGroupManager& netgroupman, const CChainParams& params, bool network_active)
: addrman(addrman_in)
, m_netgroupman{netgroupman}
, nSeed0(nSeed0In)
, nSeed1(nSeed1In)
, m_params(params)
{
SetTryNewOutboundPeer(false);
Options connOptions;
Init(connOptions);
SetNetworkActive(network_active);
}
NodeId CConnman::GetNewNodeId()
{
return nLastNodeId.fetch_add(1, std::memory_order_relaxed);
}
uint16_t CConnman::GetDefaultPort(Network net) const
{
return net == NET_I2P ? I2P_SAM31_PORT : m_params.GetDefaultPort();
}
uint16_t CConnman::GetDefaultPort(const std::string& addr) const
{
CNetAddr a;
return a.SetSpecial(addr) ? GetDefaultPort(a.GetNetwork()) : m_params.GetDefaultPort();
}
bool CConnman::Bind(const CService& addr_, unsigned int flags, NetPermissionFlags permissions)
{
const CService addr{MaybeFlipIPv6toCJDNS(addr_)};
bilingual_str strError;
if (!BindListenPort(addr, strError, permissions)) {
if ((flags & BF_REPORT_ERROR) && m_client_interface) {
m_client_interface->ThreadSafeMessageBox(strError, "", CClientUIInterface::MSG_ERROR);
}
return false;
}
if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !NetPermissions::HasFlag(permissions, NetPermissionFlags::NoBan)) {
AddLocal(addr, LOCAL_BIND);
}
return true;
}
bool CConnman::InitBinds(const Options& options)
{
bool fBound = false;
for (const auto& addrBind : options.vBinds) {
fBound |= Bind(addrBind, BF_REPORT_ERROR, NetPermissionFlags::None);
}
for (const auto& addrBind : options.vWhiteBinds) {
fBound |= Bind(addrBind.m_service, BF_REPORT_ERROR, addrBind.m_flags);
}
for (const auto& addr_bind : options.onion_binds) {
fBound |= Bind(addr_bind, BF_DONT_ADVERTISE, NetPermissionFlags::None);
}
if (options.bind_on_any) {
struct in_addr inaddr_any;
inaddr_any.s_addr = htonl(INADDR_ANY);
struct in6_addr inaddr6_any = IN6ADDR_ANY_INIT;
fBound |= Bind(CService(inaddr6_any, GetListenPort()), BF_NONE, NetPermissionFlags::None);
fBound |= Bind(CService(inaddr_any, GetListenPort()), !fBound ? BF_REPORT_ERROR : BF_NONE, NetPermissionFlags::None);
}
return fBound;
}
bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
Init(connOptions);
if (fListen && !InitBinds(connOptions)) {
if (m_client_interface) {
m_client_interface->ThreadSafeMessageBox(
_("Failed to listen on any port. Use -listen=0 if you want this."),
"", CClientUIInterface::MSG_ERROR);
}
return false;
}
Proxy i2p_sam;
if (GetProxy(NET_I2P, i2p_sam) && connOptions.m_i2p_accept_incoming) {
m_i2p_sam_session = std::make_unique<i2p::sam::Session>(gArgs.GetDataDirNet() / "i2p_private_key",
i2p_sam, &interruptNet);
}
for (const auto& strDest : connOptions.vSeedNodes) {
AddAddrFetch(strDest);
}
if (m_use_addrman_outgoing) {
// Load addresses from anchors.dat
m_anchors = ReadAnchors(gArgs.GetDataDirNet() / ANCHORS_DATABASE_FILENAME);
if (m_anchors.size() > MAX_BLOCK_RELAY_ONLY_ANCHORS) {
m_anchors.resize(MAX_BLOCK_RELAY_ONLY_ANCHORS);
}
LogPrintf("%i block-relay-only anchors will be tried for connections.\n", m_anchors.size());
}
if (m_client_interface) {
m_client_interface->InitMessage(_("Starting network threads…").translated);
}
fAddressesInitialized = true;
if (semOutbound == nullptr) {
// initialize semaphore
semOutbound = std::make_unique<CSemaphore>(std::min(m_max_automatic_outbound, m_max_automatic_connections));
}
if (semAddnode == nullptr) {
// initialize semaphore
semAddnode = std::make_unique<CSemaphore>(m_max_addnode);
}
//
// Start threads
//
assert(m_msgproc);
interruptNet.reset();
flagInterruptMsgProc = false;
{
LOCK(mutexMsgProc);
fMsgProcWake = false;
}
// Send and receive from sockets, accept connections
threadSocketHandler = std::thread(&util::TraceThread, "net", [this] { ThreadSocketHandler(); });
if (!gArgs.GetBoolArg("-dnsseed", DEFAULT_DNSSEED))
LogPrintf("DNS seeding disabled\n");
else
threadDNSAddressSeed = std::thread(&util::TraceThread, "dnsseed", [this] { ThreadDNSAddressSeed(); });
// Initiate manual connections
threadOpenAddedConnections = std::thread(&util::TraceThread, "addcon", [this] { ThreadOpenAddedConnections(); });
if (connOptions.m_use_addrman_outgoing && !connOptions.m_specified_outgoing.empty()) {
if (m_client_interface) {
m_client_interface->ThreadSafeMessageBox(
_("Cannot provide specific connections and have addrman find outgoing connections at the same time."),
"", CClientUIInterface::MSG_ERROR);
}
return false;
}
if (connOptions.m_use_addrman_outgoing || !connOptions.m_specified_outgoing.empty()) {
threadOpenConnections = std::thread(
&util::TraceThread, "opencon",
[this, connect = connOptions.m_specified_outgoing] { ThreadOpenConnections(connect); });
}
// Process messages
threadMessageHandler = std::thread(&util::TraceThread, "msghand", [this] { ThreadMessageHandler(); });
if (m_i2p_sam_session) {
threadI2PAcceptIncoming =
std::thread(&util::TraceThread, "i2paccept", [this] { ThreadI2PAcceptIncoming(); });
}
// Dump network addresses
scheduler.scheduleEvery([this] { DumpAddresses(); }, DUMP_PEERS_INTERVAL);
// Run the ASMap Health check once and then schedule it to run every 24h.
if (m_netgroupman.UsingASMap()) {
ASMapHealthCheck();
scheduler.scheduleEvery([this] { ASMapHealthCheck(); }, ASMAP_HEALTH_CHECK_INTERVAL);
}
return true;
}
class CNetCleanup
{
public:
CNetCleanup() = default;
~CNetCleanup()
{
#ifdef WIN32
// Shutdown Windows Sockets
WSACleanup();
#endif
}
};
static CNetCleanup instance_of_cnetcleanup;
void CConnman::Interrupt()
{
{
LOCK(mutexMsgProc);
flagInterruptMsgProc = true;
}
condMsgProc.notify_all();
interruptNet();
g_socks5_interrupt();
if (semOutbound) {
for (int i=0; i<m_max_automatic_outbound; i++) {
semOutbound->post();
}
}
if (semAddnode) {
for (int i=0; i<m_max_addnode; i++) {
semAddnode->post();
}
}
}
void CConnman::StopThreads()
{
if (threadI2PAcceptIncoming.joinable()) {
threadI2PAcceptIncoming.join();
}
if (threadMessageHandler.joinable())
threadMessageHandler.join();
if (threadOpenConnections.joinable())
threadOpenConnections.join();
if (threadOpenAddedConnections.joinable())
threadOpenAddedConnections.join();
if (threadDNSAddressSeed.joinable())
threadDNSAddressSeed.join();
if (threadSocketHandler.joinable())
threadSocketHandler.join();
}
void CConnman::StopNodes()
{
if (fAddressesInitialized) {
DumpAddresses();
fAddressesInitialized = false;
if (m_use_addrman_outgoing) {
// Anchor connections are only dumped during clean shutdown.
std::vector<CAddress> anchors_to_dump = GetCurrentBlockRelayOnlyConns();
if (anchors_to_dump.size() > MAX_BLOCK_RELAY_ONLY_ANCHORS) {
anchors_to_dump.resize(MAX_BLOCK_RELAY_ONLY_ANCHORS);
}
DumpAnchors(gArgs.GetDataDirNet() / ANCHORS_DATABASE_FILENAME, anchors_to_dump);
}
}
// Delete peer connections.
std::vector<CNode*> nodes;
WITH_LOCK(m_nodes_mutex, nodes.swap(m_nodes));
for (CNode* pnode : nodes) {
pnode->CloseSocketDisconnect();
DeleteNode(pnode);
}
for (CNode* pnode : m_nodes_disconnected) {
DeleteNode(pnode);
}
m_nodes_disconnected.clear();
vhListenSocket.clear();
semOutbound.reset();
semAddnode.reset();
}
void CConnman::DeleteNode(CNode* pnode)
{
assert(pnode);
m_msgproc->FinalizeNode(*pnode);
delete pnode;
}
CConnman::~CConnman()
{
Interrupt();
Stop();
}
std::vector<CAddress> CConnman::GetAddresses(size_t max_addresses, size_t max_pct, std::optional<Network> network, const bool filtered) const
{
std::vector<CAddress> addresses = addrman.GetAddr(max_addresses, max_pct, network, filtered);
if (m_banman) {
addresses.erase(std::remove_if(addresses.begin(), addresses.end(),
[this](const CAddress& addr){return m_banman->IsDiscouraged(addr) || m_banman->IsBanned(addr);}),
addresses.end());
}
return addresses;
}
std::vector<CAddress> CConnman::GetAddresses(CNode& requestor, size_t max_addresses, size_t max_pct)
{
auto local_socket_bytes = requestor.addrBind.GetAddrBytes();
uint64_t cache_id = GetDeterministicRandomizer(RANDOMIZER_ID_ADDRCACHE)
.Write(requestor.ConnectedThroughNetwork())
.Write(local_socket_bytes)
// For outbound connections, the port of the bound address is randomly
// assigned by the OS and would therefore not be useful for seeding.
.Write(requestor.IsInboundConn() ? requestor.addrBind.GetPort() : 0)
.Finalize();
const auto current_time = GetTime<std::chrono::microseconds>();
auto r = m_addr_response_caches.emplace(cache_id, CachedAddrResponse{});
CachedAddrResponse& cache_entry = r.first->second;
if (cache_entry.m_cache_entry_expiration < current_time) { // If emplace() added new one it has expiration 0.
cache_entry.m_addrs_response_cache = GetAddresses(max_addresses, max_pct, /*network=*/std::nullopt);
// Choosing a proper cache lifetime is a trade-off between the privacy leak minimization
// and the usefulness of ADDR responses to honest users.
//
// Longer cache lifetime makes it more difficult for an attacker to scrape
// enough AddrMan data to maliciously infer something useful.
// By the time an attacker scraped enough AddrMan records, most of
// the records should be old enough to not leak topology info by
// e.g. analyzing real-time changes in timestamps.
//
// It takes only several hundred requests to scrape everything from an AddrMan containing 100,000 nodes,
// so ~24 hours of cache lifetime indeed makes the data less inferable by the time
// most of it could be scraped (considering that timestamps are updated via
// ADDR self-announcements and when nodes communicate).
// We also should be robust to those attacks which may not require scraping *full* victim's AddrMan
// (because even several timestamps of the same handful of nodes may leak privacy).
//
// On the other hand, longer cache lifetime makes ADDR responses
// outdated and less useful for an honest requestor, e.g. if most nodes
// in the ADDR response are no longer active.
//
// However, the churn in the network is known to be rather low. Since we consider
// nodes to be "terrible" (see IsTerrible()) if the timestamps are older than 30 days,
// max. 24 hours of "penalty" due to cache shouldn't make any meaningful difference
// in terms of the freshness of the response.
cache_entry.m_cache_entry_expiration = current_time + std::chrono::hours(21) + GetRandMillis(std::chrono::hours(6));
}
return cache_entry.m_addrs_response_cache;
}
bool CConnman::AddNode(const AddedNodeParams& add)
{
const CService resolved(LookupNumeric(add.m_added_node, GetDefaultPort(add.m_added_node)));
const bool resolved_is_valid{resolved.IsValid()};
LOCK(m_added_nodes_mutex);
for (const auto& it : m_added_node_params) {
if (add.m_added_node == it.m_added_node || (resolved_is_valid && resolved == LookupNumeric(it.m_added_node, GetDefaultPort(it.m_added_node)))) return false;
}
m_added_node_params.push_back(add);
return true;
}
bool CConnman::RemoveAddedNode(const std::string& strNode)
{
LOCK(m_added_nodes_mutex);
for (auto it = m_added_node_params.begin(); it != m_added_node_params.end(); ++it) {
if (strNode == it->m_added_node) {
m_added_node_params.erase(it);
return true;
}
}
return false;
}
bool CConnman::AddedNodesContain(const CAddress& addr) const
{
AssertLockNotHeld(m_added_nodes_mutex);
const std::string addr_str{addr.ToStringAddr()};
const std::string addr_port_str{addr.ToStringAddrPort()};
LOCK(m_added_nodes_mutex);
return (m_added_node_params.size() < 24 // bound the query to a reasonable limit
&& std::any_of(m_added_node_params.cbegin(), m_added_node_params.cend(),
[&](const auto& p) { return p.m_added_node == addr_str || p.m_added_node == addr_port_str; }));
}
size_t CConnman::GetNodeCount(ConnectionDirection flags) const
{
LOCK(m_nodes_mutex);
if (flags == ConnectionDirection::Both) // Shortcut if we want total
return m_nodes.size();
int nNum = 0;
for (const auto& pnode : m_nodes) {
if (flags & (pnode->IsInboundConn() ? ConnectionDirection::In : ConnectionDirection::Out)) {
nNum++;
}
}
return nNum;
}
uint32_t CConnman::GetMappedAS(const CNetAddr& addr) const
{
return m_netgroupman.GetMappedAS(addr);
}
void CConnman::GetNodeStats(std::vector<CNodeStats>& vstats) const
{
vstats.clear();
LOCK(m_nodes_mutex);
vstats.reserve(m_nodes.size());
for (CNode* pnode : m_nodes) {
vstats.emplace_back();
pnode->CopyStats(vstats.back());
vstats.back().m_mapped_as = GetMappedAS(pnode->addr);
}
}
bool CConnman::DisconnectNode(const std::string& strNode)
{
LOCK(m_nodes_mutex);
if (CNode* pnode = FindNode(strNode)) {
LogPrint(BCLog::NET, "disconnect by address%s matched peer=%d; disconnecting\n", (fLogIPs ? strprintf("=%s", strNode) : ""), pnode->GetId());
pnode->fDisconnect = true;
return true;
}
return false;
}
bool CConnman::DisconnectNode(const CSubNet& subnet)
{
bool disconnected = false;
LOCK(m_nodes_mutex);
for (CNode* pnode : m_nodes) {
if (subnet.Match(pnode->addr)) {
LogPrint(BCLog::NET, "disconnect by subnet%s matched peer=%d; disconnecting\n", (fLogIPs ? strprintf("=%s", subnet.ToString()) : ""), pnode->GetId());
pnode->fDisconnect = true;
disconnected = true;
}
}
return disconnected;
}
bool CConnman::DisconnectNode(const CNetAddr& addr)
{
return DisconnectNode(CSubNet(addr));
}
bool CConnman::DisconnectNode(NodeId id)
{
LOCK(m_nodes_mutex);
for(CNode* pnode : m_nodes) {
if (id == pnode->GetId()) {
LogPrint(BCLog::NET, "disconnect by id peer=%d; disconnecting\n", pnode->GetId());
pnode->fDisconnect = true;
return true;
}
}
return false;
}
void CConnman::RecordBytesRecv(uint64_t bytes)
{
nTotalBytesRecv += bytes;
}
void CConnman::RecordBytesSent(uint64_t bytes)
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
nTotalBytesSent += bytes;
const auto now = GetTime<std::chrono::seconds>();
if (nMaxOutboundCycleStartTime + MAX_UPLOAD_TIMEFRAME < now)
{
// timeframe expired, reset cycle
nMaxOutboundCycleStartTime = now;
nMaxOutboundTotalBytesSentInCycle = 0;
}
nMaxOutboundTotalBytesSentInCycle += bytes;
}
uint64_t CConnman::GetMaxOutboundTarget() const
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
return nMaxOutboundLimit;
}
std::chrono::seconds CConnman::GetMaxOutboundTimeframe() const
{
return MAX_UPLOAD_TIMEFRAME;
}
std::chrono::seconds CConnman::GetMaxOutboundTimeLeftInCycle() const
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
return GetMaxOutboundTimeLeftInCycle_();
}
std::chrono::seconds CConnman::GetMaxOutboundTimeLeftInCycle_() const
{
AssertLockHeld(m_total_bytes_sent_mutex);
if (nMaxOutboundLimit == 0)
return 0s;
if (nMaxOutboundCycleStartTime.count() == 0)
return MAX_UPLOAD_TIMEFRAME;
const std::chrono::seconds cycleEndTime = nMaxOutboundCycleStartTime + MAX_UPLOAD_TIMEFRAME;
const auto now = GetTime<std::chrono::seconds>();
return (cycleEndTime < now) ? 0s : cycleEndTime - now;
}
bool CConnman::OutboundTargetReached(bool historicalBlockServingLimit) const
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
if (nMaxOutboundLimit == 0)
return false;
if (historicalBlockServingLimit)
{
// keep a large enough buffer to at least relay each block once
const std::chrono::seconds timeLeftInCycle = GetMaxOutboundTimeLeftInCycle_();
const uint64_t buffer = timeLeftInCycle / std::chrono::minutes{10} * MAX_BLOCK_SERIALIZED_SIZE;
if (buffer >= nMaxOutboundLimit || nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit - buffer)
return true;
}
else if (nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit)
return true;
return false;
}
uint64_t CConnman::GetOutboundTargetBytesLeft() const
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
if (nMaxOutboundLimit == 0)
return 0;
return (nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit) ? 0 : nMaxOutboundLimit - nMaxOutboundTotalBytesSentInCycle;
}
uint64_t CConnman::GetTotalBytesRecv() const
{
return nTotalBytesRecv;
}
uint64_t CConnman::GetTotalBytesSent() const
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
LOCK(m_total_bytes_sent_mutex);
return nTotalBytesSent;
}
ServiceFlags CConnman::GetLocalServices() const
{
return nLocalServices;
}
static std::unique_ptr<Transport> MakeTransport(NodeId id, bool use_v2transport, bool inbound) noexcept
{
if (use_v2transport) {
return std::make_unique<V2Transport>(id, /*initiating=*/!inbound);
} else {
return std::make_unique<V1Transport>(id);
}
}
CNode::CNode(NodeId idIn,
std::shared_ptr<Sock> sock,
const CAddress& addrIn,
uint64_t nKeyedNetGroupIn,
uint64_t nLocalHostNonceIn,
const CAddress& addrBindIn,
const std::string& addrNameIn,
ConnectionType conn_type_in,
bool inbound_onion,
CNodeOptions&& node_opts)
: m_transport{MakeTransport(idIn, node_opts.use_v2transport, conn_type_in == ConnectionType::INBOUND)},
m_permission_flags{node_opts.permission_flags},
m_sock{sock},
m_connected{GetTime<std::chrono::seconds>()},
addr{addrIn},
addrBind{addrBindIn},
m_addr_name{addrNameIn.empty() ? addr.ToStringAddrPort() : addrNameIn},
m_dest(addrNameIn),
m_inbound_onion{inbound_onion},
m_prefer_evict{node_opts.prefer_evict},
nKeyedNetGroup{nKeyedNetGroupIn},
m_conn_type{conn_type_in},
id{idIn},
nLocalHostNonce{nLocalHostNonceIn},
m_recv_flood_size{node_opts.recv_flood_size},
m_i2p_sam_session{std::move(node_opts.i2p_sam_session)}
{
if (inbound_onion) assert(conn_type_in == ConnectionType::INBOUND);
for (const std::string &msg : getAllNetMessageTypes())
mapRecvBytesPerMsgType[msg] = 0;
mapRecvBytesPerMsgType[NET_MESSAGE_TYPE_OTHER] = 0;
if (fLogIPs) {
LogPrint(BCLog::NET, "Added connection to %s peer=%d\n", m_addr_name, id);
} else {
LogPrint(BCLog::NET, "Added connection peer=%d\n", id);
}
}
void CNode::MarkReceivedMsgsForProcessing()
{
AssertLockNotHeld(m_msg_process_queue_mutex);
size_t nSizeAdded = 0;
for (const auto& msg : vRecvMsg) {
// vRecvMsg contains only completed CNetMessage
// the single possible partially deserialized message are held by TransportDeserializer
nSizeAdded += msg.m_raw_message_size;
}
LOCK(m_msg_process_queue_mutex);
m_msg_process_queue.splice(m_msg_process_queue.end(), vRecvMsg);
m_msg_process_queue_size += nSizeAdded;
fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
}
std::optional<std::pair<CNetMessage, bool>> CNode::PollMessage()
{
LOCK(m_msg_process_queue_mutex);
if (m_msg_process_queue.empty()) return std::nullopt;
std::list<CNetMessage> msgs;
// Just take one message
msgs.splice(msgs.begin(), m_msg_process_queue, m_msg_process_queue.begin());
m_msg_process_queue_size -= msgs.front().m_raw_message_size;
fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
return std::make_pair(std::move(msgs.front()), !m_msg_process_queue.empty());
}
bool CConnman::NodeFullyConnected(const CNode* pnode)
{
return pnode && pnode->fSuccessfullyConnected && !pnode->fDisconnect;
}
void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
{
AssertLockNotHeld(m_total_bytes_sent_mutex);
size_t nMessageSize = msg.data.size();
LogPrint(BCLog::NET, "sending %s (%d bytes) peer=%d\n", msg.m_type, nMessageSize, pnode->GetId());
if (gArgs.GetBoolArg("-capturemessages", false)) {
CaptureMessage(pnode->addr, msg.m_type, msg.data, /*is_incoming=*/false);
}
TRACE6(net, outbound_message,
pnode->GetId(),
pnode->m_addr_name.c_str(),
pnode->ConnectionTypeAsString().c_str(),
msg.m_type.c_str(),
msg.data.size(),
msg.data.data()
);
size_t nBytesSent = 0;
{
LOCK(pnode->cs_vSend);
// Check if the transport still has unsent bytes, and indicate to it that we're about to
// give it a message to send.
const auto& [to_send, more, _msg_type] =
pnode->m_transport->GetBytesToSend(/*have_next_message=*/true);
const bool queue_was_empty{to_send.empty() && pnode->vSendMsg.empty()};
// Update memory usage of send buffer.
pnode->m_send_memusage += msg.GetMemoryUsage();
if (pnode->m_send_memusage + pnode->m_transport->GetSendMemoryUsage() > nSendBufferMaxSize) pnode->fPauseSend = true;
// Move message to vSendMsg queue.
pnode->vSendMsg.push_back(std::move(msg));
// If there was nothing to send before, and there is now (predicted by the "more" value
// returned by the GetBytesToSend call above), attempt "optimistic write":
// because the poll/select loop may pause for SELECT_TIMEOUT_MILLISECONDS before actually
// doing a send, try sending from the calling thread if the queue was empty before.
// With a V1Transport, more will always be true here, because adding a message always
// results in sendable bytes there, but with V2Transport this is not the case (it may
// still be in the handshake).
if (queue_was_empty && more) {
std::tie(nBytesSent, std::ignore) = SocketSendData(*pnode);
}
}
if (nBytesSent) RecordBytesSent(nBytesSent);
}
bool CConnman::ForNode(NodeId id, std::function<bool(CNode* pnode)> func)
{
CNode* found = nullptr;
LOCK(m_nodes_mutex);
for (auto&& pnode : m_nodes) {
if(pnode->GetId() == id) {
found = pnode;
break;
}
}
return found != nullptr && NodeFullyConnected(found) && func(found);
}
CSipHasher CConnman::GetDeterministicRandomizer(uint64_t id) const
{
return CSipHasher(nSeed0, nSeed1).Write(id);
}
uint64_t CConnman::CalculateKeyedNetGroup(const CAddress& address) const
{
std::vector<unsigned char> vchNetGroup(m_netgroupman.GetGroup(address));
return GetDeterministicRandomizer(RANDOMIZER_ID_NETGROUP).Write(vchNetGroup).Finalize();
}
void CConnman::PerformReconnections()
{
AssertLockNotHeld(m_reconnections_mutex);
AssertLockNotHeld(m_unused_i2p_sessions_mutex);
while (true) {
// Move first element of m_reconnections to todo (avoiding an allocation inside the lock).
decltype(m_reconnections) todo;
{
LOCK(m_reconnections_mutex);
if (m_reconnections.empty()) break;
todo.splice(todo.end(), m_reconnections, m_reconnections.begin());
}
auto& item = *todo.begin();
OpenNetworkConnection(item.addr_connect,
// We only reconnect if the first attempt to connect succeeded at
// connection time, but then failed after the CNode object was
// created. Since we already know connecting is possible, do not
// count failure to reconnect.
/*fCountFailure=*/false,
std::move(item.grant),
item.destination.empty() ? nullptr : item.destination.c_str(),
item.conn_type,
item.use_v2transport);
}
}
void CConnman::ASMapHealthCheck()
{
const std::vector<CAddress> v4_addrs{GetAddresses(/*max_addresses=*/ 0, /*max_pct=*/ 0, Network::NET_IPV4, /*filtered=*/ false)};
const std::vector<CAddress> v6_addrs{GetAddresses(/*max_addresses=*/ 0, /*max_pct=*/ 0, Network::NET_IPV6, /*filtered=*/ false)};
std::vector<CNetAddr> clearnet_addrs;
clearnet_addrs.reserve(v4_addrs.size() + v6_addrs.size());
std::transform(v4_addrs.begin(), v4_addrs.end(), std::back_inserter(clearnet_addrs),
[](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
std::transform(v6_addrs.begin(), v6_addrs.end(), std::back_inserter(clearnet_addrs),
[](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
m_netgroupman.ASMapHealthCheck(clearnet_addrs);
}
// Dump binary message to file, with timestamp.
static void CaptureMessageToFile(const CAddress& addr,
const std::string& msg_type,
Span<const unsigned char> data,
bool is_incoming)
{
// Note: This function captures the message at the time of processing,
// not at socket receive/send time.
// This ensures that the messages are always in order from an application
// layer (processing) perspective.
auto now = GetTime<std::chrono::microseconds>();
// Windows folder names cannot include a colon
std::string clean_addr = addr.ToStringAddrPort();
std::replace(clean_addr.begin(), clean_addr.end(), ':', '_');
fs::path base_path = gArgs.GetDataDirNet() / "message_capture" / fs::u8path(clean_addr);
fs::create_directories(base_path);
fs::path path = base_path / (is_incoming ? "msgs_recv.dat" : "msgs_sent.dat");
AutoFile f{fsbridge::fopen(path, "ab")};
ser_writedata64(f, now.count());
f << Span{msg_type};
for (auto i = msg_type.length(); i < CMessageHeader::COMMAND_SIZE; ++i) {
f << uint8_t{'\0'};
}
uint32_t size = data.size();
ser_writedata32(f, size);
f << data;
}
std::function<void(const CAddress& addr,
const std::string& msg_type,
Span<const unsigned char> data,
bool is_incoming)>
CaptureMessage = CaptureMessageToFile;
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