// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2020 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #if defined(HAVE_CONFIG_H) #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef WIN32 #include #else #include #endif #ifdef USE_POLL #include #endif #include #include #include #include #include /** 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(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}; // We add a random period time (0 to 1 seconds) to feeler connections to prevent synchronization. #define FEELER_SLEEP_WINDOW 1 // MSG_NOSIGNAL is not available on some platforms, if it doesn't exist define it as 0 #if !defined(MSG_NOSIGNAL) #define MSG_NOSIGNAL 0 #endif // MSG_DONTWAIT is not available on some platforms, if it doesn't exist define it as 0 #if !defined(MSG_DONTWAIT) #define MSG_DONTWAIT 0 #endif /** Used to pass flags to the Bind() function */ enum BindFlags { BF_NONE = 0, BF_EXPLICIT = (1U << 0), BF_REPORT_ERROR = (1U << 1), /** * 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 << 2), }; // 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_COMMAND_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; RecursiveMutex cs_mapLocalHost; std::map mapLocalHost GUARDED_BY(cs_mapLocalHost); static bool vfLimited[NET_MAX] GUARDED_BY(cs_mapLocalHost) = {}; std::string strSubVersion; void CConnman::AddAddrFetch(const std::string& strDest) { LOCK(m_addr_fetches_mutex); m_addr_fetches.push_back(strDest); } uint16_t GetListenPort() { return (uint16_t)(gArgs.GetArg("-port", Params().GetDefaultPort())); } // find 'best' local address for a particular peer bool GetLocal(CService& addr, const CNetAddr *paddrPeer) { if (!fListen) return false; int nBestScore = -1; int nBestReachability = -1; { LOCK(cs_mapLocalHost); for (const auto& entry : mapLocalHost) { int nScore = entry.second.nScore; int nReachability = entry.first.GetReachabilityFrom(paddrPeer); if (nReachability > nBestReachability || (nReachability == nBestReachability && nScore > nBestScore)) { addr = CService(entry.first, entry.second.nPort); nBestReachability = nReachability; nBestScore = nScore; } } } return nBestScore >= 0; } //! Convert the pnSeed6 array into usable address objects. static std::vector convertSeed6(const std::vector &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 int64_t nOneWeek = 7*24*60*60; std::vector vSeedsOut; vSeedsOut.reserve(vSeedsIn.size()); FastRandomContext rng; for (const auto& seed_in : vSeedsIn) { struct in6_addr ip; memcpy(&ip, seed_in.addr, sizeof(ip)); CAddress addr(CService(ip, seed_in.port), GetDesirableServiceFlags(NODE_NONE)); addr.nTime = GetTime() - rng.randrange(nOneWeek) - nOneWeek; vSeedsOut.push_back(addr); } return vSeedsOut; } // get best local address for a particular peer as a CAddress // Otherwise, 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. CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices) { CAddress ret(CService(CNetAddr(),GetListenPort()), nLocalServices); CService addr; if (GetLocal(addr, paddrPeer)) { ret = CAddress(addr, nLocalServices); } ret.nTime = GetAdjustedTime(); return ret; } static int GetnScore(const CService& addr) { LOCK(cs_mapLocalHost); if (mapLocalHost.count(addr) == 0) return 0; return mapLocalHost[addr].nScore; } // Is our peer's addrLocal potentially useful as an external IP source? bool IsPeerAddrLocalGood(CNode *pnode) { CService addrLocal = pnode->GetAddrLocal(); return fDiscover && pnode->addr.IsRoutable() && addrLocal.IsRoutable() && IsReachable(addrLocal.GetNetwork()); } // pushes our own address to a peer void AdvertiseLocal(CNode *pnode) { if (fListen && pnode->fSuccessfullyConnected) { CAddress addrLocal = GetLocalAddress(&pnode->addr, pnode->GetLocalServices()); if (gArgs.GetBoolArg("-addrmantest", false)) { // use IPv4 loopback during addrmantest addrLocal = CAddress(CService(LookupNumeric("127.0.0.1", GetListenPort())), pnode->GetLocalServices()); } // 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(pnode) && (!addrLocal.IsRoutable() || rng.randbits((GetnScore(addrLocal) > LOCAL_MANUAL) ? 3 : 1) == 0)) { addrLocal.SetIP(pnode->GetAddrLocal()); } if (addrLocal.IsRoutable() || gArgs.GetBoolArg("-addrmantest", false)) { LogPrint(BCLog::NET, "AdvertiseLocal: advertising address %s\n", addrLocal.ToString()); pnode->PushAddress(addrLocal, rng); } } } // learn a new local address bool AddLocal(const CService& addr, int nScore) { if (!addr.IsRoutable()) return false; if (!fDiscover && nScore < LOCAL_MANUAL) return false; if (!IsReachable(addr)) return false; LogPrintf("AddLocal(%s,%i)\n", addr.ToString(), nScore); { LOCK(cs_mapLocalHost); bool fAlready = mapLocalHost.count(addr) > 0; LocalServiceInfo &info = mapLocalHost[addr]; if (!fAlready || nScore >= info.nScore) { info.nScore = nScore + (fAlready ? 1 : 0); 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(cs_mapLocalHost); LogPrintf("RemoveLocal(%s)\n", addr.ToString()); mapLocalHost.erase(addr); } void SetReachable(enum Network net, bool reachable) { if (net == NET_UNROUTABLE || net == NET_INTERNAL) return; LOCK(cs_mapLocalHost); vfLimited[net] = !reachable; } bool IsReachable(enum Network net) { LOCK(cs_mapLocalHost); return !vfLimited[net]; } bool IsReachable(const CNetAddr &addr) { return IsReachable(addr.GetNetwork()); } /** vote for a local address */ bool SeenLocal(const CService& addr) { { LOCK(cs_mapLocalHost); if (mapLocalHost.count(addr) == 0) return false; mapLocalHost[addr].nScore++; } return true; } /** check whether a given address is potentially local */ bool IsLocal(const CService& addr) { LOCK(cs_mapLocalHost); return mapLocalHost.count(addr) > 0; } CNode* CConnman::FindNode(const CNetAddr& ip) { LOCK(cs_vNodes); for (CNode* pnode : vNodes) { if (static_cast(pnode->addr) == ip) { return pnode; } } return nullptr; } CNode* CConnman::FindNode(const CSubNet& subNet) { LOCK(cs_vNodes); for (CNode* pnode : vNodes) { if (subNet.Match(static_cast(pnode->addr))) { return pnode; } } return nullptr; } CNode* CConnman::FindNode(const std::string& addrName) { LOCK(cs_vNodes); for (CNode* pnode : vNodes) { if (pnode->GetAddrName() == addrName) { return pnode; } } return nullptr; } CNode* CConnman::FindNode(const CService& addr) { LOCK(cs_vNodes); for (CNode* pnode : vNodes) { if (static_cast(pnode->addr) == addr) { return pnode; } } return nullptr; } bool CConnman::AlreadyConnectedToAddress(const CAddress& addr) { return FindNode(static_cast(addr)) || FindNode(addr.ToStringIPPort()); } bool CConnman::CheckIncomingNonce(uint64_t nonce) { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (!pnode->fSuccessfullyConnected && !pnode->IsInboundConn() && pnode->GetLocalNonce() == nonce) return false; } return true; } /** Get the bind address for a socket as CAddress */ static CAddress GetBindAddress(SOCKET sock) { CAddress addr_bind; struct sockaddr_storage sockaddr_bind; socklen_t sockaddr_bind_len = sizeof(sockaddr_bind); if (sock != INVALID_SOCKET) { if (!getsockname(sock, (struct sockaddr*)&sockaddr_bind, &sockaddr_bind_len)) { addr_bind.SetSockAddr((const struct sockaddr*)&sockaddr_bind); } else { LogPrint(BCLog::NET, "Warning: getsockname failed\n"); } } return addr_bind; } CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure, ConnectionType conn_type) { assert(conn_type != ConnectionType::INBOUND); if (pszDest == nullptr) { if (IsLocal(addrConnect)) return nullptr; // Look for an existing connection CNode* pnode = FindNode(static_cast(addrConnect)); if (pnode) { LogPrintf("Failed to open new connection, already connected\n"); return nullptr; } } /// debug print LogPrint(BCLog::NET, "trying connection %s lastseen=%.1fhrs\n", pszDest ? pszDest : addrConnect.ToString(), pszDest ? 0.0 : (double)(GetAdjustedTime() - addrConnect.nTime)/3600.0); // Resolve const int default_port = Params().GetDefaultPort(); if (pszDest) { std::vector resolved; if (Lookup(pszDest, resolved, default_port, fNameLookup && !HaveNameProxy(), 256) && !resolved.empty()) { addrConnect = CAddress(resolved[GetRand(resolved.size())], NODE_NONE); if (!addrConnect.IsValid()) { LogPrint(BCLog::NET, "Resolver returned invalid address %s for %s\n", addrConnect.ToString(), 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, and return the existing CNode instead. // Also store the name we used to connect in that CNode, so that future FindNode() calls to that // name catch this early. LOCK(cs_vNodes); CNode* pnode = FindNode(static_cast(addrConnect)); if (pnode) { pnode->MaybeSetAddrName(std::string(pszDest)); LogPrintf("Failed to open new connection, already connected\n"); return nullptr; } } } // Connect bool connected = false; SOCKET hSocket = INVALID_SOCKET; proxyType proxy; if (addrConnect.IsValid()) { bool proxyConnectionFailed = false; if (GetProxy(addrConnect.GetNetwork(), proxy)) { hSocket = CreateSocket(proxy.proxy); if (hSocket == INVALID_SOCKET) { return nullptr; } connected = ConnectThroughProxy(proxy, addrConnect.ToStringIP(), addrConnect.GetPort(), hSocket, nConnectTimeout, proxyConnectionFailed); } else { // no proxy needed (none set for target network) hSocket = CreateSocket(addrConnect); if (hSocket == INVALID_SOCKET) { return nullptr; } connected = ConnectSocketDirectly(addrConnect, hSocket, nConnectTimeout, 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(addrConnect, fCountFailure); } } else if (pszDest && GetNameProxy(proxy)) { hSocket = CreateSocket(proxy.proxy); if (hSocket == INVALID_SOCKET) { return nullptr; } std::string host; int port = default_port; SplitHostPort(std::string(pszDest), port, host); bool proxyConnectionFailed; connected = ConnectThroughProxy(proxy, host, port, hSocket, nConnectTimeout, proxyConnectionFailed); } if (!connected) { CloseSocket(hSocket); return nullptr; } // Add node NodeId id = GetNewNodeId(); uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize(); CAddress addr_bind = GetBindAddress(hSocket); CNode* pnode = new CNode(id, nLocalServices, hSocket, addrConnect, CalculateKeyedNetGroup(addrConnect), nonce, addr_bind, pszDest ? pszDest : "", conn_type); pnode->AddRef(); // We're making a new connection, harvest entropy from the time (and our peer count) RandAddEvent((uint32_t)id); return pnode; } void CNode::CloseSocketDisconnect() { fDisconnect = true; LOCK(cs_hSocket); if (hSocket != INVALID_SOCKET) { LogPrint(BCLog::NET, "disconnecting peer=%d\n", id); CloseSocket(hSocket); } } void CConnman::AddWhitelistPermissionFlags(NetPermissionFlags& flags, const CNetAddr &addr) const { for (const auto& subnet : vWhitelistedRange) { if (subnet.m_subnet.Match(addr)) NetPermissions::AddFlag(flags, subnet.m_flags); } } std::string ConnectionTypeAsString(ConnectionType conn_type) { switch (conn_type) { case ConnectionType::INBOUND: return "inbound"; case ConnectionType::MANUAL: return "manual"; case ConnectionType::FEELER: return "feeler"; case ConnectionType::OUTBOUND_FULL_RELAY: return "outbound-full-relay"; case ConnectionType::BLOCK_RELAY: return "block-relay-only"; case ConnectionType::ADDR_FETCH: return "addr-fetch"; } // no default case, so the compiler can warn about missing cases assert(false); } std::string CNode::GetAddrName() const { LOCK(cs_addrName); return addrName; } void CNode::MaybeSetAddrName(const std::string& addrNameIn) { LOCK(cs_addrName); if (addrName.empty()) { addrName = addrNameIn; } } CService CNode::GetAddrLocal() const { LOCK(cs_addrLocal); return addrLocal; } void CNode::SetAddrLocal(const CService& addrLocalIn) { LOCK(cs_addrLocal); if (addrLocal.IsValid()) { error("Addr local already set for node: %i. Refusing to change from %s to %s", id, addrLocal.ToString(), addrLocalIn.ToString()); } else { addrLocal = addrLocalIn; } } Network CNode::ConnectedThroughNetwork() const { return m_inbound_onion ? NET_ONION : addr.GetNetClass(); } #undef X #define X(name) stats.name = name void CNode::copyStats(CNodeStats &stats, const std::vector &m_asmap) { stats.nodeid = this->GetId(); X(nServices); X(addr); X(addrBind); stats.m_network = ConnectedThroughNetwork(); stats.m_mapped_as = addr.GetMappedAS(m_asmap); if (m_tx_relay != nullptr) { LOCK(m_tx_relay->cs_filter); stats.fRelayTxes = m_tx_relay->fRelayTxes; } else { stats.fRelayTxes = false; } X(nLastSend); X(nLastRecv); X(nLastTXTime); X(nLastBlockTime); X(nTimeConnected); X(nTimeOffset); stats.addrName = GetAddrName(); X(nVersion); { LOCK(cs_SubVer); X(cleanSubVer); } stats.fInbound = IsInboundConn(); X(m_bip152_highbandwidth_to); X(m_bip152_highbandwidth_from); { LOCK(cs_vSend); X(mapSendBytesPerMsgCmd); X(nSendBytes); } { LOCK(cs_vRecv); X(mapRecvBytesPerMsgCmd); X(nRecvBytes); } X(m_permissionFlags); if (m_tx_relay != nullptr) { stats.minFeeFilter = m_tx_relay->minFeeFilter; } else { stats.minFeeFilter = 0; } // It is common for nodes with good ping times to suddenly become lagged, // due to a new block arriving or other large transfer. // Merely reporting pingtime might fool the caller into thinking the node was still responsive, // since pingtime does not update until the ping is complete, which might take a while. // So, if a ping is taking an unusually long time in flight, // the caller can immediately detect that this is happening. std::chrono::microseconds ping_wait{0}; if ((0 != nPingNonceSent) && (0 != m_ping_start.load().count())) { ping_wait = GetTime() - m_ping_start.load(); } // Raw ping time is in microseconds, but show it to user as whole seconds (Bitcoin users should be well used to small numbers with many decimal places by now :) stats.m_ping_usec = nPingUsecTime; stats.m_min_ping_usec = nMinPingUsecTime; stats.m_ping_wait_usec = count_microseconds(ping_wait); // Leave string empty if addrLocal invalid (not filled in yet) CService addrLocalUnlocked = GetAddrLocal(); stats.addrLocal = addrLocalUnlocked.IsValid() ? addrLocalUnlocked.ToString() : ""; X(m_conn_type); } #undef X bool CNode::ReceiveMsgBytes(Span msg_bytes, bool& complete) { complete = false; const auto time = GetTime(); LOCK(cs_vRecv); nLastRecv = std::chrono::duration_cast(time).count(); nRecvBytes += msg_bytes.size(); while (msg_bytes.size() > 0) { // absorb network data int handled = m_deserializer->Read(msg_bytes); if (handled < 0) { // Serious header problem, disconnect from the peer. return false; } if (m_deserializer->Complete()) { // decompose a transport agnostic CNetMessage from the deserializer uint32_t out_err_raw_size{0}; Optional result{m_deserializer->GetMessage(time, out_err_raw_size)}; if (!result) { // Message deserialization failed. Drop the message but don't disconnect the peer. // store the size of the corrupt message mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER)->second += out_err_raw_size; continue; } //store received bytes per message command //to prevent a memory DOS, only allow valid commands mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(result->m_command); if (i == mapRecvBytesPerMsgCmd.end()) i = mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER); assert(i != mapRecvBytesPerMsgCmd.end()); i->second += result->m_raw_message_size; // push the message to the process queue, vRecvMsg.push_back(std::move(*result)); complete = true; } } return true; } int V1TransportDeserializer::readHeader(Span msg_bytes) { // copy data to temporary parsing buffer unsigned int nRemaining = CMessageHeader::HEADER_SIZE - nHdrPos; unsigned int nCopy = std::min(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 (memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) { LogPrint(BCLog::NET, "HEADER ERROR - MESSAGESTART (%s, %u bytes), received %s, peer=%d\n", hdr.GetCommand(), hdr.nMessageSize, 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 (%s, %u bytes), peer=%d\n", hdr.GetCommand(), hdr.nMessageSize, m_node_id); return -1; } // switch state to reading message data in_data = true; return nCopy; } int V1TransportDeserializer::readData(Span msg_bytes) { unsigned int nRemaining = hdr.nMessageSize - nDataPos; unsigned int nCopy = std::min(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& V1TransportDeserializer::GetMessageHash() const { assert(Complete()); if (data_hash.IsNull()) hasher.Finalize(data_hash); return data_hash; } Optional V1TransportDeserializer::GetMessage(const std::chrono::microseconds time, uint32_t& out_err_raw_size) { // decompose a single CNetMessage from the TransportDeserializer Optional msg(std::move(vRecv)); // store command string, time, and sizes msg->m_command = 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 command string if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) { LogPrint(BCLog::NET, "CHECKSUM ERROR (%s, %u bytes), expected %s was %s, peer=%d\n", SanitizeString(msg->m_command), msg->m_message_size, HexStr(Span(hash.begin(), hash.begin() + CMessageHeader::CHECKSUM_SIZE)), HexStr(hdr.pchChecksum), m_node_id); out_err_raw_size = msg->m_raw_message_size; msg = nullopt; } else if (!hdr.IsCommandValid()) { LogPrint(BCLog::NET, "HEADER ERROR - COMMAND (%s, %u bytes), peer=%d\n", hdr.GetCommand(), msg->m_message_size, m_node_id); out_err_raw_size = msg->m_raw_message_size; msg = nullopt; } // Always reset the network deserializer (prepare for the next message) Reset(); return msg; } void V1TransportSerializer::prepareForTransport(CSerializedNetMsg& msg, std::vector& header) { // create dbl-sha256 checksum uint256 hash = Hash(msg.data); // create header CMessageHeader hdr(Params().MessageStart(), msg.m_type.c_str(), msg.data.size()); memcpy(hdr.pchChecksum, hash.begin(), CMessageHeader::CHECKSUM_SIZE); // serialize header header.reserve(CMessageHeader::HEADER_SIZE); CVectorWriter{SER_NETWORK, INIT_PROTO_VERSION, header, 0, hdr}; } size_t CConnman::SocketSendData(CNode& node) const { auto it = node.vSendMsg.begin(); size_t nSentSize = 0; while (it != node.vSendMsg.end()) { const auto& data = *it; assert(data.size() > node.nSendOffset); int nBytes = 0; { LOCK(node.cs_hSocket); if (node.hSocket == INVALID_SOCKET) break; nBytes = send(node.hSocket, reinterpret_cast(data.data()) + node.nSendOffset, data.size() - node.nSendOffset, MSG_NOSIGNAL | MSG_DONTWAIT); } if (nBytes > 0) { node.nLastSend = GetSystemTimeInSeconds(); node.nSendBytes += nBytes; node.nSendOffset += nBytes; nSentSize += nBytes; if (node.nSendOffset == data.size()) { node.nSendOffset = 0; node.nSendSize -= data.size(); node.fPauseSend = node.nSendSize > nSendBufferMaxSize; it++; } else { // 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(); } } // couldn't send anything at all break; } } if (it == node.vSendMsg.end()) { assert(node.nSendOffset == 0); assert(node.nSendSize == 0); } node.vSendMsg.erase(node.vSendMsg.begin(), it); return nSentSize; } static bool ReverseCompareNodeMinPingTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { return a.nMinPingUsecTime > b.nMinPingUsecTime; } static bool ReverseCompareNodeTimeConnected(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { return a.nTimeConnected > b.nTimeConnected; } static bool CompareLocalHostTimeConnected(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { if (a.m_is_local != b.m_is_local) return b.m_is_local; return a.nTimeConnected > b.nTimeConnected; } static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { return a.nKeyedNetGroup < b.nKeyedNetGroup; } static bool CompareNodeBlockTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { // There is a fall-through here because it is common for a node to have many peers which have not yet relayed a block. if (a.nLastBlockTime != b.nLastBlockTime) return a.nLastBlockTime < b.nLastBlockTime; if (a.fRelevantServices != b.fRelevantServices) return b.fRelevantServices; return a.nTimeConnected > b.nTimeConnected; } static bool CompareNodeTXTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { // There is a fall-through here because it is common for a node to have more than a few peers that have not yet relayed txn. if (a.nLastTXTime != b.nLastTXTime) return a.nLastTXTime < b.nLastTXTime; if (a.fRelayTxes != b.fRelayTxes) return b.fRelayTxes; if (a.fBloomFilter != b.fBloomFilter) return a.fBloomFilter; return a.nTimeConnected > b.nTimeConnected; } // Pick out the potential block-relay only peers, and sort them by last block time. static bool CompareNodeBlockRelayOnlyTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { if (a.fRelayTxes != b.fRelayTxes) return a.fRelayTxes; if (a.nLastBlockTime != b.nLastBlockTime) return a.nLastBlockTime < b.nLastBlockTime; if (a.fRelevantServices != b.fRelevantServices) return b.fRelevantServices; return a.nTimeConnected > b.nTimeConnected; } //! Sort an array by the specified comparator, then erase the last K elements. template static void EraseLastKElements(std::vector &elements, Comparator comparator, size_t k) { std::sort(elements.begin(), elements.end(), comparator); size_t eraseSize = std::min(k, elements.size()); elements.erase(elements.end() - eraseSize, elements.end()); } [[nodiscard]] Optional SelectNodeToEvict(std::vector&& vEvictionCandidates) { // Protect connections with certain characteristics // Deterministically select 4 peers to protect by netgroup. // An attacker cannot predict which netgroups will be protected EraseLastKElements(vEvictionCandidates, CompareNetGroupKeyed, 4); // Protect the 8 nodes with the lowest minimum ping time. // An attacker cannot manipulate this metric without physically moving nodes closer to the target. EraseLastKElements(vEvictionCandidates, ReverseCompareNodeMinPingTime, 8); // Protect 4 nodes that most recently sent us novel transactions accepted into our mempool. // An attacker cannot manipulate this metric without performing useful work. EraseLastKElements(vEvictionCandidates, CompareNodeTXTime, 4); // Protect up to 8 non-tx-relay peers that have sent us novel blocks. std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeBlockRelayOnlyTime); size_t erase_size = std::min(size_t(8), vEvictionCandidates.size()); vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.end() - erase_size, vEvictionCandidates.end(), [](NodeEvictionCandidate const &n) { return !n.fRelayTxes && n.fRelevantServices; }), vEvictionCandidates.end()); // Protect 4 nodes that most recently sent us novel blocks. // An attacker cannot manipulate this metric without performing useful work. EraseLastKElements(vEvictionCandidates, CompareNodeBlockTime, 4); // Protect the half of the remaining nodes which have been connected the longest. // This replicates the non-eviction implicit behavior, and precludes attacks that start later. // Reserve half of these protected spots for localhost peers, even if // they're not longest-uptime overall. This helps protect tor peers, which // tend to be otherwise disadvantaged under our eviction criteria. size_t initial_size = vEvictionCandidates.size(); size_t total_protect_size = initial_size / 2; // Pick out up to 1/4 peers that are localhost, sorted by longest uptime. std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareLocalHostTimeConnected); size_t local_erase_size = total_protect_size / 2; vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.end() - local_erase_size, vEvictionCandidates.end(), [](NodeEvictionCandidate const &n) { return n.m_is_local; }), vEvictionCandidates.end()); // Calculate how many we removed, and update our total number of peers that // we want to protect based on uptime accordingly. total_protect_size -= initial_size - vEvictionCandidates.size(); EraseLastKElements(vEvictionCandidates, ReverseCompareNodeTimeConnected, total_protect_size); if (vEvictionCandidates.empty()) return nullopt; // If any remaining peers are preferred for eviction consider only them. // This happens after the other preferences since if a peer is really the best by other criteria (esp relaying blocks) // then we probably don't want to evict it no matter what. if (std::any_of(vEvictionCandidates.begin(),vEvictionCandidates.end(),[](NodeEvictionCandidate const &n){return n.prefer_evict;})) { vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.begin(),vEvictionCandidates.end(), [](NodeEvictionCandidate const &n){return !n.prefer_evict;}),vEvictionCandidates.end()); } // Identify the network group with the most connections and youngest member. // (vEvictionCandidates is already sorted by reverse connect time) uint64_t naMostConnections; unsigned int nMostConnections = 0; int64_t nMostConnectionsTime = 0; std::map > mapNetGroupNodes; for (const NodeEvictionCandidate &node : vEvictionCandidates) { std::vector &group = mapNetGroupNodes[node.nKeyedNetGroup]; group.push_back(node); int64_t grouptime = group[0].nTimeConnected; if (group.size() > nMostConnections || (group.size() == nMostConnections && grouptime > nMostConnectionsTime)) { nMostConnections = group.size(); nMostConnectionsTime = grouptime; naMostConnections = node.nKeyedNetGroup; } } // Reduce to the network group with the most connections vEvictionCandidates = std::move(mapNetGroupNodes[naMostConnections]); // Disconnect from the network group with the most connections return vEvictionCandidates.front().id; } /** 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 vEvictionCandidates; { LOCK(cs_vNodes); for (const CNode* node : vNodes) { if (node->HasPermission(PF_NOBAN)) continue; if (!node->IsInboundConn()) continue; if (node->fDisconnect) continue; bool peer_relay_txes = false; bool peer_filter_not_null = false; if (node->m_tx_relay != nullptr) { LOCK(node->m_tx_relay->cs_filter); peer_relay_txes = node->m_tx_relay->fRelayTxes; peer_filter_not_null = node->m_tx_relay->pfilter != nullptr; } NodeEvictionCandidate candidate = {node->GetId(), node->nTimeConnected, node->nMinPingUsecTime, node->nLastBlockTime, node->nLastTXTime, HasAllDesirableServiceFlags(node->nServices), peer_relay_txes, peer_filter_not_null, node->nKeyedNetGroup, node->m_prefer_evict, node->addr.IsLocal()}; vEvictionCandidates.push_back(candidate); } } const Optional node_id_to_evict = SelectNodeToEvict(std::move(vEvictionCandidates)); if (!node_id_to_evict) { return false; } LOCK(cs_vNodes); for (CNode* pnode : vNodes) { 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); SOCKET hSocket = accept(hListenSocket.socket, (struct sockaddr*)&sockaddr, &len); CAddress addr; int nInbound = 0; int nMaxInbound = nMaxConnections - m_max_outbound; if (hSocket != INVALID_SOCKET) { if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr)) { LogPrintf("Warning: Unknown socket family\n"); } } NetPermissionFlags permissionFlags = NetPermissionFlags::PF_NONE; hListenSocket.AddSocketPermissionFlags(permissionFlags); AddWhitelistPermissionFlags(permissionFlags, addr); if (NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_ISIMPLICIT)) { NetPermissions::ClearFlag(permissionFlags, PF_ISIMPLICIT); if (gArgs.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY)) NetPermissions::AddFlag(permissionFlags, PF_FORCERELAY); if (gArgs.GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY)) NetPermissions::AddFlag(permissionFlags, PF_RELAY); NetPermissions::AddFlag(permissionFlags, PF_MEMPOOL); NetPermissions::AddFlag(permissionFlags, PF_NOBAN); } { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->IsInboundConn()) nInbound++; } } if (hSocket == INVALID_SOCKET) { int nErr = WSAGetLastError(); if (nErr != WSAEWOULDBLOCK) LogPrintf("socket error accept failed: %s\n", NetworkErrorString(nErr)); return; } if (!fNetworkActive) { LogPrint(BCLog::NET, "connection from %s dropped: not accepting new connections\n", addr.ToString()); CloseSocket(hSocket); return; } if (!IsSelectableSocket(hSocket)) { LogPrintf("connection from %s dropped: non-selectable socket\n", addr.ToString()); CloseSocket(hSocket); return; } // According to the internet TCP_NODELAY is not carried into accepted sockets // on all platforms. Set it again here just to be sure. SetSocketNoDelay(hSocket); // Don't accept connections from banned peers. bool banned = m_banman && m_banman->IsBanned(addr); if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && banned) { LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToString()); CloseSocket(hSocket); 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(permissionFlags, NetPermissionFlags::PF_NOBAN) && nInbound + 1 >= nMaxInbound && discouraged) { LogPrint(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToString()); CloseSocket(hSocket); return; } if (nInbound >= nMaxInbound) { if (!AttemptToEvictConnection()) { // No connection to evict, disconnect the new connection LogPrint(BCLog::NET, "failed to find an eviction candidate - connection dropped (full)\n"); CloseSocket(hSocket); return; } } NodeId id = GetNewNodeId(); uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize(); CAddress addr_bind = GetBindAddress(hSocket); ServiceFlags nodeServices = nLocalServices; if (NetPermissions::HasFlag(permissionFlags, PF_BLOOMFILTER)) { nodeServices = static_cast(nodeServices | NODE_BLOOM); } const bool inbound_onion = std::find(m_onion_binds.begin(), m_onion_binds.end(), addr_bind) != m_onion_binds.end(); CNode* pnode = new CNode(id, nodeServices, hSocket, addr, CalculateKeyedNetGroup(addr), nonce, addr_bind, "", ConnectionType::INBOUND, inbound_onion); pnode->AddRef(); pnode->m_permissionFlags = permissionFlags; pnode->m_prefer_evict = discouraged; m_msgproc->InitializeNode(pnode); LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToString()); { LOCK(cs_vNodes); vNodes.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) { if (conn_type != ConnectionType::OUTBOUND_FULL_RELAY && conn_type != ConnectionType::BLOCK_RELAY) return false; const int max_connections = conn_type == ConnectionType::OUTBOUND_FULL_RELAY ? m_max_outbound_full_relay : m_max_outbound_block_relay; // Count existing connections int existing_connections = WITH_LOCK(cs_vNodes, return std::count_if(vNodes.begin(), vNodes.end(), [conn_type](CNode* node) { return node->m_conn_type == conn_type; });); // Max connections of specified type already exist if (existing_connections >= max_connections) return false; // Max total outbound connections already exist CSemaphoreGrant grant(*semOutbound, true); if (!grant) return false; OpenNetworkConnection(CAddress(), false, &grant, address.c_str(), conn_type); return true; } void CConnman::DisconnectNodes() { { LOCK(cs_vNodes); if (!fNetworkActive) { // Disconnect any connected nodes for (CNode* pnode : vNodes) { if (!pnode->fDisconnect) { LogPrint(BCLog::NET, "Network not active, dropping peer=%d\n", pnode->GetId()); pnode->fDisconnect = true; } } } // Disconnect unused nodes std::vector vNodesCopy = vNodes; for (CNode* pnode : vNodesCopy) { if (pnode->fDisconnect) { // remove from vNodes vNodes.erase(remove(vNodes.begin(), vNodes.end(), pnode), vNodes.end()); // release outbound grant (if any) pnode->grantOutbound.Release(); // close socket and cleanup pnode->CloseSocketDisconnect(); // hold in disconnected pool until all refs are released pnode->Release(); vNodesDisconnected.push_back(pnode); } } } { // Delete disconnected nodes std::list vNodesDisconnectedCopy = vNodesDisconnected; for (CNode* pnode : vNodesDisconnectedCopy) { // wait until threads are done using it if (pnode->GetRefCount() <= 0) { bool fDelete = false; { TRY_LOCK(pnode->cs_vSend, lockSend); if (lockSend) { fDelete = true; } } if (fDelete) { vNodesDisconnected.remove(pnode); DeleteNode(pnode); } } } } } void CConnman::NotifyNumConnectionsChanged() { size_t vNodesSize; { LOCK(cs_vNodes); vNodesSize = vNodes.size(); } if(vNodesSize != nPrevNodeCount) { nPrevNodeCount = vNodesSize; if(clientInterface) clientInterface->NotifyNumConnectionsChanged(vNodesSize); } } bool CConnman::InactivityCheck(const CNode& node) const { // Use non-mockable system time (otherwise these timers will pop when we // use setmocktime in the tests). int64_t now = GetSystemTimeInSeconds(); if (now <= node.nTimeConnected + m_peer_connect_timeout) { // Only run inactivity checks if the peer has been connected longer // than m_peer_connect_timeout. return false; } if (node.nLastRecv == 0 || node.nLastSend == 0) { LogPrint(BCLog::NET, "socket no message in first %i seconds, %d %d peer=%d\n", m_peer_connect_timeout, node.nLastRecv != 0, node.nLastSend != 0, node.GetId()); return true; } if (now > node.nLastSend + TIMEOUT_INTERVAL) { LogPrint(BCLog::NET, "socket sending timeout: %is peer=%d\n", now - node.nLastSend, node.GetId()); return true; } if (now > node.nLastRecv + TIMEOUT_INTERVAL) { LogPrint(BCLog::NET, "socket receive timeout: %is peer=%d\n", now - node.nLastRecv, node.GetId()); return true; } if (node.nPingNonceSent && node.m_ping_start.load() + std::chrono::seconds{TIMEOUT_INTERVAL} < GetTime()) { // We use mockable time for ping timeouts. This means that setmocktime // may cause pings to time out for peers that have been connected for // longer than m_peer_connect_timeout. LogPrint(BCLog::NET, "ping timeout: %fs peer=%d\n", 0.000001 * count_microseconds(GetTime() - node.m_ping_start.load()), node.GetId()); return true; } if (!node.fSuccessfullyConnected) { LogPrint(BCLog::NET, "version handshake timeout peer=%d\n", node.GetId()); return true; } return false; } bool CConnman::GenerateSelectSet(std::set &recv_set, std::set &send_set, std::set &error_set) { for (const ListenSocket& hListenSocket : vhListenSocket) { recv_set.insert(hListenSocket.socket); } { LOCK(cs_vNodes); for (CNode* pnode : vNodes) { // Implement the following logic: // * If there is data to send, select() for sending data. As this only // happens when optimistic write failed, we choose to first drain the // write buffer in this case before receiving more. This avoids // needlessly queueing received data, if the remote peer is not themselves // receiving data. This means properly utilizing TCP flow control signalling. // * Otherwise, if there is space left in the receive buffer, select() for // receiving data. // * Hand off all complete messages to the processor, to be handled without // blocking here. bool select_recv = !pnode->fPauseRecv; bool select_send; { LOCK(pnode->cs_vSend); select_send = !pnode->vSendMsg.empty(); } LOCK(pnode->cs_hSocket); if (pnode->hSocket == INVALID_SOCKET) continue; error_set.insert(pnode->hSocket); if (select_send) { send_set.insert(pnode->hSocket); continue; } if (select_recv) { recv_set.insert(pnode->hSocket); } } } return !recv_set.empty() || !send_set.empty() || !error_set.empty(); } #ifdef USE_POLL void CConnman::SocketEvents(std::set &recv_set, std::set &send_set, std::set &error_set) { std::set recv_select_set, send_select_set, error_select_set; if (!GenerateSelectSet(recv_select_set, send_select_set, error_select_set)) { interruptNet.sleep_for(std::chrono::milliseconds(SELECT_TIMEOUT_MILLISECONDS)); return; } std::unordered_map pollfds; for (SOCKET socket_id : recv_select_set) { pollfds[socket_id].fd = socket_id; pollfds[socket_id].events |= POLLIN; } for (SOCKET socket_id : send_select_set) { pollfds[socket_id].fd = socket_id; pollfds[socket_id].events |= POLLOUT; } for (SOCKET socket_id : error_select_set) { pollfds[socket_id].fd = socket_id; // These flags are ignored, but we set them for clarity pollfds[socket_id].events |= POLLERR|POLLHUP; } std::vector vpollfds; vpollfds.reserve(pollfds.size()); for (auto it : pollfds) { vpollfds.push_back(std::move(it.second)); } if (poll(vpollfds.data(), vpollfds.size(), SELECT_TIMEOUT_MILLISECONDS) < 0) return; if (interruptNet) return; for (struct pollfd pollfd_entry : vpollfds) { if (pollfd_entry.revents & POLLIN) recv_set.insert(pollfd_entry.fd); if (pollfd_entry.revents & POLLOUT) send_set.insert(pollfd_entry.fd); if (pollfd_entry.revents & (POLLERR|POLLHUP)) error_set.insert(pollfd_entry.fd); } } #else void CConnman::SocketEvents(std::set &recv_set, std::set &send_set, std::set &error_set) { std::set recv_select_set, send_select_set, error_select_set; if (!GenerateSelectSet(recv_select_set, send_select_set, error_select_set)) { interruptNet.sleep_for(std::chrono::milliseconds(SELECT_TIMEOUT_MILLISECONDS)); return; } // // Find which sockets have data to receive // struct timeval timeout; timeout.tv_sec = 0; timeout.tv_usec = SELECT_TIMEOUT_MILLISECONDS * 1000; // frequency to poll pnode->vSend fd_set fdsetRecv; fd_set fdsetSend; fd_set fdsetError; FD_ZERO(&fdsetRecv); FD_ZERO(&fdsetSend); FD_ZERO(&fdsetError); SOCKET hSocketMax = 0; for (SOCKET hSocket : recv_select_set) { FD_SET(hSocket, &fdsetRecv); hSocketMax = std::max(hSocketMax, hSocket); } for (SOCKET hSocket : send_select_set) { FD_SET(hSocket, &fdsetSend); hSocketMax = std::max(hSocketMax, hSocket); } for (SOCKET hSocket : error_select_set) { FD_SET(hSocket, &fdsetError); hSocketMax = std::max(hSocketMax, hSocket); } int nSelect = select(hSocketMax + 1, &fdsetRecv, &fdsetSend, &fdsetError, &timeout); if (interruptNet) return; if (nSelect == SOCKET_ERROR) { int nErr = WSAGetLastError(); LogPrintf("socket select error %s\n", NetworkErrorString(nErr)); for (unsigned int i = 0; i <= hSocketMax; i++) FD_SET(i, &fdsetRecv); FD_ZERO(&fdsetSend); FD_ZERO(&fdsetError); if (!interruptNet.sleep_for(std::chrono::milliseconds(SELECT_TIMEOUT_MILLISECONDS))) return; } for (SOCKET hSocket : recv_select_set) { if (FD_ISSET(hSocket, &fdsetRecv)) { recv_set.insert(hSocket); } } for (SOCKET hSocket : send_select_set) { if (FD_ISSET(hSocket, &fdsetSend)) { send_set.insert(hSocket); } } for (SOCKET hSocket : error_select_set) { if (FD_ISSET(hSocket, &fdsetError)) { error_set.insert(hSocket); } } } #endif void CConnman::SocketHandler() { std::set recv_set, send_set, error_set; SocketEvents(recv_set, send_set, error_set); if (interruptNet) return; // // Accept new connections // for (const ListenSocket& hListenSocket : vhListenSocket) { if (hListenSocket.socket != INVALID_SOCKET && recv_set.count(hListenSocket.socket) > 0) { AcceptConnection(hListenSocket); } } // // Service each socket // std::vector vNodesCopy; { LOCK(cs_vNodes); vNodesCopy = vNodes; for (CNode* pnode : vNodesCopy) pnode->AddRef(); } for (CNode* pnode : vNodesCopy) { if (interruptNet) return; // // Receive // bool recvSet = false; bool sendSet = false; bool errorSet = false; { LOCK(pnode->cs_hSocket); if (pnode->hSocket == INVALID_SOCKET) continue; recvSet = recv_set.count(pnode->hSocket) > 0; sendSet = send_set.count(pnode->hSocket) > 0; errorSet = error_set.count(pnode->hSocket) > 0; } if (recvSet || errorSet) { // typical socket buffer is 8K-64K uint8_t pchBuf[0x10000]; int nBytes = 0; { LOCK(pnode->cs_hSocket); if (pnode->hSocket == INVALID_SOCKET) continue; nBytes = recv(pnode->hSocket, (char*)pchBuf, sizeof(pchBuf), MSG_DONTWAIT); } if (nBytes > 0) { bool notify = false; if (!pnode->ReceiveMsgBytes(Span(pchBuf, nBytes), notify)) pnode->CloseSocketDisconnect(); RecordBytesRecv(nBytes); if (notify) { size_t nSizeAdded = 0; auto it(pnode->vRecvMsg.begin()); for (; it != pnode->vRecvMsg.end(); ++it) { // vRecvMsg contains only completed CNetMessage // the single possible partially deserialized message are held by TransportDeserializer nSizeAdded += it->m_raw_message_size; } { LOCK(pnode->cs_vProcessMsg); pnode->vProcessMsg.splice(pnode->vProcessMsg.end(), pnode->vRecvMsg, pnode->vRecvMsg.begin(), it); pnode->nProcessQueueSize += nSizeAdded; pnode->fPauseRecv = pnode->nProcessQueueSize > nReceiveFloodSize; } 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 (sendSet) { // Send data size_t bytes_sent = WITH_LOCK(pnode->cs_vSend, return SocketSendData(*pnode)); if (bytes_sent) RecordBytesSent(bytes_sent); } if (InactivityCheck(*pnode)) pnode->fDisconnect = true; } { LOCK(cs_vNodes); for (CNode* pnode : vNodesCopy) pnode->Release(); } } void CConnman::ThreadSocketHandler() { while (!interruptNet) { DisconnectNodes(); NotifyNumConnectionsChanged(); SocketHandler(); } } void CConnman::WakeMessageHandler() { { LOCK(mutexMsgProc); fMsgProcWake = true; } condMsgProc.notify_one(); } void CConnman::ThreadDNSAddressSeed() { FastRandomContext rng; std::vector seeds = Params().DNSSeeds(); Shuffle(seeds.begin(), seeds.end(), rng); int seeds_right_now = 0; // Number of seeds left before testing if we have enough connections int found = 0; 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(); } // 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) 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; int nRelevant = 0; { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->fSuccessfullyConnected && pnode->IsOutboundOrBlockRelayConn()) ++nRelevant; } } if (nRelevant >= 2) { 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 (HaveNameProxy()) { AddAddrFetch(seed); } else { std::vector vIPs; std::vector vAdd; ServiceFlags requiredServiceBits = GetDesirableServiceFlags(NODE_NONE); std::string host = strprintf("x%x.%s", requiredServiceBits, seed); CNetAddr resolveSource; if (!resolveSource.SetInternal(host)) { continue; } unsigned int nMaxIPs = 256; // Limits number of IPs learned from a DNS seed if (LookupHost(host, vIPs, nMaxIPs, true)) { for (const CNetAddr& ip : vIPs) { int nOneDay = 24*3600; CAddress addr = CAddress(CService(ip, Params().GetDefaultPort()), requiredServiceBits); addr.nTime = GetTime() - 3*nOneDay - rng.randrange(4*nOneDay); // use a random age between 3 and 7 days old vAdd.push_back(addr); found++; } addrman.Add(vAdd, resolveSource); } else { // We now avoid directly using results from DNS Seeds which do not support service bit filtering, // instead using them as a addrfetch to get nodes with our desired service bits. AddAddrFetch(seed); } } --seeds_right_now; } LogPrintf("%d addresses found from DNS seeds\n", found); } void CConnman::DumpAddresses() { int64_t nStart = GetTimeMillis(); CAddrDB adb; adb.Write(addrman); LogPrint(BCLog::NET, "Flushed %d addresses to peers.dat %dms\n", addrman.size(), GetTimeMillis() - nStart); } void CConnman::ProcessAddrFetch() { std::string strDest; { LOCK(m_addr_fetches_mutex); if (m_addr_fetches.empty()) return; strDest = m_addr_fetches.front(); m_addr_fetches.pop_front(); } CAddress addr; CSemaphoreGrant grant(*semOutbound, true); if (grant) { OpenNetworkConnection(addr, false, &grant, strDest.c_str(), ConnectionType::ADDR_FETCH); } } bool CConnman::GetTryNewOutboundPeer() { return m_try_another_outbound_peer; } void CConnman::SetTryNewOutboundPeer(bool flag) { m_try_another_outbound_peer = flag; LogPrint(BCLog::NET, "net: setting try another outbound peer=%s\n", flag ? "true" : "false"); } // 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() { int full_outbound_peers = 0; { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { 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() { int block_relay_peers = 0; { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->fSuccessfullyConnected && !pnode->fDisconnect && pnode->IsBlockOnlyConn()) { ++block_relay_peers; } } } return std::max(block_relay_peers - m_max_outbound_block_relay, 0); } void CConnman::ThreadOpenConnections(const std::vector connect) { // Connect to specific addresses if (!connect.empty()) { for (int64_t nLoop = 0;; nLoop++) { ProcessAddrFetch(); for (const std::string& strAddr : connect) { CAddress addr(CService(), NODE_NONE); OpenNetworkConnection(addr, false, nullptr, strAddr.c_str(), ConnectionType::MANUAL); 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; } } // Initiate network connections int64_t nStart = GetTime(); // Minimum time before next feeler connection (in microseconds). int64_t nNextFeeler = PoissonNextSend(nStart*1000*1000, FEELER_INTERVAL); int64_t nNextExtraBlockRelay = PoissonNextSend(nStart*1000*1000, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL); while (!interruptNet) { ProcessAddrFetch(); if (!interruptNet.sleep_for(std::chrono::milliseconds(500))) return; CSemaphoreGrant grant(*semOutbound); if (interruptNet) return; // Add seed nodes if DNS seeds are all down (an infrastructure attack?). // Note that we only do this if we started with an empty peers.dat, // (in which case we will query DNS seeds immediately) *and* the DNS // seeds have not returned any results. if (addrman.size() == 0 && (GetTime() - nStart > 60)) { static bool done = false; if (!done) { LogPrintf("Adding fixed seed nodes as DNS doesn't seem to be available.\n"); CNetAddr local; local.SetInternal("fixedseeds"); addrman.Add(convertSeed6(Params().FixedSeeds()), local); done = true; } } // // Choose an address to connect to based on most recently seen // CAddress addrConnect; // Only connect out to one peer per network group (/16 for IPv4). int nOutboundFullRelay = 0; int nOutboundBlockRelay = 0; std::set > setConnected; { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->IsFullOutboundConn()) nOutboundFullRelay++; if (pnode->IsBlockOnlyConn()) nOutboundBlockRelay++; // Netgroups for inbound and manual peers are not excluded because our goal here // is to not use multiple of our limited outbound slots on a single netgroup // but inbound and manual peers do not use our outbound slots. Inbound peers // also have the added issue that they could be attacker controlled and used // to prevent us from connecting to particular hosts if we used them here. switch (pnode->m_conn_type) { case ConnectionType::INBOUND: case ConnectionType::MANUAL: break; case ConnectionType::OUTBOUND_FULL_RELAY: case ConnectionType::BLOCK_RELAY: case ConnectionType::ADDR_FETCH: case ConnectionType::FEELER: setConnected.insert(pnode->addr.GetGroup(addrman.m_asmap)); } // no default case, so the compiler can warn about missing cases } } ConnectionType conn_type = ConnectionType::OUTBOUND_FULL_RELAY; int64_t nTime = GetTimeMicros(); bool anchor = false; bool fFeeler = false; // 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 nNextFeeler // 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 (nTime > nNextExtraBlockRelay && 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 a poisson 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). nNextExtraBlockRelay = PoissonNextSend(nTime, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL); conn_type = ConnectionType::BLOCK_RELAY; } else if (nTime > nNextFeeler) { nNextFeeler = PoissonNextSend(nTime, FEELER_INTERVAL); conn_type = ConnectionType::FEELER; fFeeler = true; } else { // skip to next iteration of while loop continue; } addrman.ResolveCollisions(); int64_t nANow = GetAdjustedTime(); 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) || !IsReachable(addr) || !HasAllDesirableServiceFlags(addr.nServices) || setConnected.count(addr.GetGroup(addrman.m_asmap))) continue; addrConnect = addr; LogPrint(BCLog::NET, "Trying to make an anchor connection to %s\n", addrConnect.ToString()); 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; CAddrInfo addr; if (fFeeler) { // First, try to get a tried table collision address. This returns // an empty (invalid) address if there are no collisions to try. addr = addrman.SelectTriedCollision(); if (!addr.IsValid()) { // No tried table collisions. Select a new table address // for our feeler. addr = 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. addr = addrman.Select(true); } } else { // Not a feeler addr = addrman.Select(); } // Require outbound connections, other than feelers, to be to distinct network groups if (!fFeeler && setConnected.count(addr.GetGroup(addrman.m_asmap))) { break; } // if we selected an invalid or local address, restart if (!addr.IsValid() || IsLocal(addr)) { break; } if (!IsReachable(addr)) continue; // only consider very recently tried nodes after 30 failed attempts if (nANow - addr.nLastTry < 600 && 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 && !HasAllDesirableServiceFlags(addr.nServices)) { continue; } else if (fFeeler && !MayHaveUsefulAddressDB(addr.nServices)) { continue; } // Do not allow non-default ports, unless after 50 invalid // addresses selected already. This is to prevent malicious peers // from advertising themselves as a service on another host and // port, causing a DoS attack as nodes around the network attempt // to connect to it fruitlessly. if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50) continue; addrConnect = addr; break; } if (addrConnect.IsValid()) { if (fFeeler) { // Add small amount of random noise before connection to avoid synchronization. int randsleep = GetRandInt(FEELER_SLEEP_WINDOW * 1000); if (!interruptNet.sleep_for(std::chrono::milliseconds(randsleep))) return; LogPrint(BCLog::NET, "Making feeler connection to %s\n", addrConnect.ToString()); } OpenNetworkConnection(addrConnect, (int)setConnected.size() >= std::min(nMaxConnections - 1, 2), &grant, nullptr, conn_type); } } } std::vector CConnman::GetCurrentBlockRelayOnlyConns() const { std::vector ret; LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->IsBlockOnlyConn()) { ret.push_back(pnode->addr); } } return ret; } std::vector CConnman::GetAddedNodeInfo() { std::vector ret; std::list lAddresses(0); { LOCK(cs_vAddedNodes); ret.reserve(vAddedNodes.size()); std::copy(vAddedNodes.cbegin(), vAddedNodes.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 mapConnected; std::map> mapConnectedByName; { LOCK(cs_vNodes); for (const CNode* pnode : vNodes) { if (pnode->addr.IsValid()) { mapConnected[pnode->addr] = pnode->IsInboundConn(); } std::string addrName = pnode->GetAddrName(); if (!addrName.empty()) { mapConnectedByName[std::move(addrName)] = std::make_pair(pnode->IsInboundConn(), static_cast(pnode->addr)); } } } for (const std::string& strAddNode : lAddresses) { CService service(LookupNumeric(strAddNode, Params().GetDefaultPort())); AddedNodeInfo addedNode{strAddNode, CService(), false, false}; if (service.IsValid()) { // strAddNode is an IP:port auto it = mapConnected.find(service); if (it != mapConnected.end()) { addedNode.resolvedAddress = service; addedNode.fConnected = true; addedNode.fInbound = it->second; } } else { // strAddNode is a name auto it = mapConnectedByName.find(strAddNode); if (it != mapConnectedByName.end()) { addedNode.resolvedAddress = it->second.second; addedNode.fConnected = true; addedNode.fInbound = it->second.first; } } ret.emplace_back(std::move(addedNode)); } return ret; } void CConnman::ThreadOpenAddedConnections() { while (true) { CSemaphoreGrant grant(*semAddnode); std::vector vInfo = GetAddedNodeInfo(); bool tried = false; for (const AddedNodeInfo& info : vInfo) { if (!info.fConnected) { if (!grant.TryAcquire()) { // 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, &grant, info.strAddedNode.c_str(), ConnectionType::MANUAL); if (!interruptNet.sleep_for(std::chrono::milliseconds(500))) return; } } // 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 *grantOutbound, const char *pszDest, ConnectionType conn_type) { 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); if (!pnode) return; if (grantOutbound) grantOutbound->MoveTo(pnode->grantOutbound); m_msgproc->InitializeNode(pnode); { LOCK(cs_vNodes); vNodes.push_back(pnode); } } void CConnman::ThreadMessageHandler() { while (!flagInterruptMsgProc) { std::vector vNodesCopy; { LOCK(cs_vNodes); vNodesCopy = vNodes; for (CNode* pnode : vNodesCopy) { pnode->AddRef(); } } bool fMoreWork = false; for (CNode* pnode : vNodesCopy) { if (pnode->fDisconnect) continue; // Receive messages bool fMoreNodeWork = m_msgproc->ProcessMessages(pnode, flagInterruptMsgProc); fMoreWork |= (fMoreNodeWork && !pnode->fPauseSend); if (flagInterruptMsgProc) return; // Send messages { LOCK(pnode->cs_sendProcessing); m_msgproc->SendMessages(pnode); } if (flagInterruptMsgProc) return; } { LOCK(cs_vNodes); for (CNode* pnode : vNodesCopy) pnode->Release(); } 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; } } 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("Error: Bind address family for %s not supported"), addrBind.ToString()); LogPrintf("%s\n", strError.original); return false; } SOCKET hListenSocket = CreateSocket(addrBind); if (hListenSocket == INVALID_SOCKET) { strError = strprintf(Untranslated("Error: Couldn't open socket for incoming connections (socket returned error %s)"), NetworkErrorString(WSAGetLastError())); LogPrintf("%s\n", strError.original); return false; } // Allow binding if the port is still in TIME_WAIT state after // the program was closed and restarted. setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (sockopt_arg_type)&nOne, sizeof(int)); // 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 setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_V6ONLY, (sockopt_arg_type)&nOne, sizeof(int)); #endif #ifdef WIN32 int nProtLevel = PROTECTION_LEVEL_UNRESTRICTED; setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_PROTECTION_LEVEL, (const char*)&nProtLevel, sizeof(int)); #endif } if (::bind(hListenSocket, (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.ToString(), PACKAGE_NAME); else strError = strprintf(_("Unable to bind to %s on this computer (bind returned error %s)"), addrBind.ToString(), NetworkErrorString(nErr)); LogPrintf("%s\n", strError.original); CloseSocket(hListenSocket); return false; } LogPrintf("Bound to %s\n", addrBind.ToString()); // Listen for incoming connections if (listen(hListenSocket, SOMAXCONN) == SOCKET_ERROR) { strError = strprintf(_("Error: Listening for incoming connections failed (listen returned error %s)"), NetworkErrorString(WSAGetLastError())); LogPrintf("%s\n", strError.original); CloseSocket(hListenSocket); return false; } vhListenSocket.push_back(ListenSocket(hListenSocket, permissions)); return true; } void Discover() { if (!fDiscover) return; #ifdef WIN32 // Get local host IP char pszHostName[256] = ""; if (gethostname(pszHostName, sizeof(pszHostName)) != SOCKET_ERROR) { std::vector vaddr; if (LookupHost(pszHostName, vaddr, 0, true)) { for (const CNetAddr &addr : vaddr) { if (AddLocal(addr, LOCAL_IF)) LogPrintf("%s: %s - %s\n", __func__, pszHostName, addr.ToString()); } } } #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.ToString()); } 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.ToString()); } } freeifaddrs(myaddrs); } #endif } void CConnman::SetNetworkActive(bool active) { LogPrintf("%s: %s\n", __func__, active); if (fNetworkActive == active) { return; } fNetworkActive = active; uiInterface.NotifyNetworkActiveChanged(fNetworkActive); } CConnman::CConnman(uint64_t nSeed0In, uint64_t nSeed1In, bool network_active) : nSeed0(nSeed0In), nSeed1(nSeed1In) { SetTryNewOutboundPeer(false); Options connOptions; Init(connOptions); SetNetworkActive(network_active); } NodeId CConnman::GetNewNodeId() { return nLastNodeId.fetch_add(1, std::memory_order_relaxed); } bool CConnman::Bind(const CService &addr, unsigned int flags, NetPermissionFlags permissions) { if (!(flags & BF_EXPLICIT) && !IsReachable(addr)) return false; bilingual_str strError; if (!BindListenPort(addr, strError, permissions)) { if ((flags & BF_REPORT_ERROR) && clientInterface) { clientInterface->ThreadSafeMessageBox(strError, "", CClientUIInterface::MSG_ERROR); } return false; } if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !(permissions & PF_NOBAN)) { AddLocal(addr, LOCAL_BIND); } return true; } bool CConnman::InitBinds( const std::vector& binds, const std::vector& whiteBinds, const std::vector& onion_binds) { bool fBound = false; for (const auto& addrBind : binds) { fBound |= Bind(addrBind, (BF_EXPLICIT | BF_REPORT_ERROR), NetPermissionFlags::PF_NONE); } for (const auto& addrBind : whiteBinds) { fBound |= Bind(addrBind.m_service, (BF_EXPLICIT | BF_REPORT_ERROR), addrBind.m_flags); } if (binds.empty() && whiteBinds.empty()) { 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::PF_NONE); fBound |= Bind(CService(inaddr_any, GetListenPort()), !fBound ? BF_REPORT_ERROR : BF_NONE, NetPermissionFlags::PF_NONE); } for (const auto& addr_bind : onion_binds) { fBound |= Bind(addr_bind, BF_EXPLICIT | BF_DONT_ADVERTISE, NetPermissionFlags::PF_NONE); } return fBound; } bool CConnman::Start(CScheduler& scheduler, const Options& connOptions) { Init(connOptions); if (fListen && !InitBinds(connOptions.vBinds, connOptions.vWhiteBinds, connOptions.onion_binds)) { if (clientInterface) { clientInterface->ThreadSafeMessageBox( _("Failed to listen on any port. Use -listen=0 if you want this."), "", CClientUIInterface::MSG_ERROR); } return false; } for (const auto& strDest : connOptions.vSeedNodes) { AddAddrFetch(strDest); } if (clientInterface) { clientInterface->InitMessage(_("Loading P2P addresses...").translated); } // Load addresses from peers.dat int64_t nStart = GetTimeMillis(); { CAddrDB adb; if (adb.Read(addrman)) LogPrintf("Loaded %i addresses from peers.dat %dms\n", addrman.size(), GetTimeMillis() - nStart); else { addrman.Clear(); // Addrman can be in an inconsistent state after failure, reset it LogPrintf("Invalid or missing peers.dat; recreating\n"); DumpAddresses(); } } if (m_use_addrman_outgoing) { // Load addresses from anchors.dat m_anchors = ReadAnchors(GetDataDir() / 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()); } uiInterface.InitMessage(_("Starting network threads...").translated); fAddressesInitialized = true; if (semOutbound == nullptr) { // initialize semaphore semOutbound = MakeUnique(std::min(m_max_outbound, nMaxConnections)); } if (semAddnode == nullptr) { // initialize semaphore semAddnode = MakeUnique(nMaxAddnode); } // // Start threads // assert(m_msgproc); InterruptSocks5(false); interruptNet.reset(); flagInterruptMsgProc = false; { LOCK(mutexMsgProc); fMsgProcWake = false; } // Send and receive from sockets, accept connections threadSocketHandler = std::thread(&TraceThread >, "net", std::function(std::bind(&CConnman::ThreadSocketHandler, this))); if (!gArgs.GetBoolArg("-dnsseed", true)) LogPrintf("DNS seeding disabled\n"); else threadDNSAddressSeed = std::thread(&TraceThread >, "dnsseed", std::function(std::bind(&CConnman::ThreadDNSAddressSeed, this))); // Initiate manual connections threadOpenAddedConnections = std::thread(&TraceThread >, "addcon", std::function(std::bind(&CConnman::ThreadOpenAddedConnections, this))); if (connOptions.m_use_addrman_outgoing && !connOptions.m_specified_outgoing.empty()) { if (clientInterface) { clientInterface->ThreadSafeMessageBox( _("Cannot provide specific connections and have addrman find outgoing connections at the same."), "", CClientUIInterface::MSG_ERROR); } return false; } if (connOptions.m_use_addrman_outgoing || !connOptions.m_specified_outgoing.empty()) threadOpenConnections = std::thread(&TraceThread >, "opencon", std::function(std::bind(&CConnman::ThreadOpenConnections, this, connOptions.m_specified_outgoing))); // Process messages threadMessageHandler = std::thread(&TraceThread >, "msghand", std::function(std::bind(&CConnman::ThreadMessageHandler, this))); // Dump network addresses scheduler.scheduleEvery([this] { DumpAddresses(); }, DUMP_PEERS_INTERVAL); return true; } class CNetCleanup { public: CNetCleanup() {} ~CNetCleanup() { #ifdef WIN32 // Shutdown Windows Sockets WSACleanup(); #endif } }; static CNetCleanup instance_of_cnetcleanup; void CConnman::Interrupt() { { LOCK(mutexMsgProc); flagInterruptMsgProc = true; } condMsgProc.notify_all(); interruptNet(); InterruptSocks5(true); if (semOutbound) { for (int i=0; ipost(); } } if (semAddnode) { for (int i=0; ipost(); } } } void CConnman::StopThreads() { 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 anchors_to_dump = GetCurrentBlockRelayOnlyConns(); if (anchors_to_dump.size() > MAX_BLOCK_RELAY_ONLY_ANCHORS) { anchors_to_dump.resize(MAX_BLOCK_RELAY_ONLY_ANCHORS); } DumpAnchors(GetDataDir() / ANCHORS_DATABASE_FILENAME, anchors_to_dump); } } // Close sockets LOCK(cs_vNodes); for (CNode* pnode : vNodes) pnode->CloseSocketDisconnect(); for (ListenSocket& hListenSocket : vhListenSocket) if (hListenSocket.socket != INVALID_SOCKET) if (!CloseSocket(hListenSocket.socket)) LogPrintf("CloseSocket(hListenSocket) failed with error %s\n", NetworkErrorString(WSAGetLastError())); // clean up some globals (to help leak detection) for (CNode* pnode : vNodes) { DeleteNode(pnode); } for (CNode* pnode : vNodesDisconnected) { DeleteNode(pnode); } vNodes.clear(); vNodesDisconnected.clear(); vhListenSocket.clear(); semOutbound.reset(); semAddnode.reset(); } void CConnman::DeleteNode(CNode* pnode) { assert(pnode); bool fUpdateConnectionTime = false; m_msgproc->FinalizeNode(*pnode, fUpdateConnectionTime); if (fUpdateConnectionTime) { addrman.Connected(pnode->addr); } delete pnode; } CConnman::~CConnman() { Interrupt(); Stop(); } void CConnman::SetServices(const CService &addr, ServiceFlags nServices) { addrman.SetServices(addr, nServices); } void CConnman::MarkAddressGood(const CAddress& addr) { addrman.Good(addr); } bool CConnman::AddNewAddresses(const std::vector& vAddr, const CAddress& addrFrom, int64_t nTimePenalty) { return addrman.Add(vAddr, addrFrom, nTimePenalty); } std::vector CConnman::GetAddresses(size_t max_addresses, size_t max_pct) { std::vector addresses = addrman.GetAddr(max_addresses, max_pct); 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 CConnman::GetAddresses(CNode& requestor, size_t max_addresses, size_t max_pct) { SOCKET socket; WITH_LOCK(requestor.cs_hSocket, socket = requestor.hSocket); auto local_socket_bytes = GetBindAddress(socket).GetAddrBytes(); uint64_t cache_id = GetDeterministicRandomizer(RANDOMIZER_ID_ADDRCACHE) .Write(requestor.addr.GetNetwork()) .Write(local_socket_bytes.data(), local_socket_bytes.size()) .Finalize(); const auto current_time = GetTime(); 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); // 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 std::string& strNode) { LOCK(cs_vAddedNodes); for (const std::string& it : vAddedNodes) { if (strNode == it) return false; } vAddedNodes.push_back(strNode); return true; } bool CConnman::RemoveAddedNode(const std::string& strNode) { LOCK(cs_vAddedNodes); for(std::vector::iterator it = vAddedNodes.begin(); it != vAddedNodes.end(); ++it) { if (strNode == *it) { vAddedNodes.erase(it); return true; } } return false; } size_t CConnman::GetNodeCount(NumConnections flags) { LOCK(cs_vNodes); if (flags == CConnman::CONNECTIONS_ALL) // Shortcut if we want total return vNodes.size(); int nNum = 0; for (const auto& pnode : vNodes) { if (flags & (pnode->IsInboundConn() ? CONNECTIONS_IN : CONNECTIONS_OUT)) { nNum++; } } return nNum; } void CConnman::GetNodeStats(std::vector& vstats) { vstats.clear(); LOCK(cs_vNodes); vstats.reserve(vNodes.size()); for (CNode* pnode : vNodes) { vstats.emplace_back(); pnode->copyStats(vstats.back(), addrman.m_asmap); } } bool CConnman::DisconnectNode(const std::string& strNode) { LOCK(cs_vNodes); 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(cs_vNodes); for (CNode* pnode : vNodes) { 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(cs_vNodes); for(CNode* pnode : vNodes) { 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) { LOCK(cs_totalBytesRecv); nTotalBytesRecv += bytes; } void CConnman::RecordBytesSent(uint64_t bytes) { LOCK(cs_totalBytesSent); nTotalBytesSent += bytes; const auto now = GetTime(); if (nMaxOutboundCycleStartTime + MAX_UPLOAD_TIMEFRAME < now) { // timeframe expired, reset cycle nMaxOutboundCycleStartTime = now; nMaxOutboundTotalBytesSentInCycle = 0; } // TODO, exclude peers with download permission nMaxOutboundTotalBytesSentInCycle += bytes; } uint64_t CConnman::GetMaxOutboundTarget() { LOCK(cs_totalBytesSent); return nMaxOutboundLimit; } std::chrono::seconds CConnman::GetMaxOutboundTimeframe() { return MAX_UPLOAD_TIMEFRAME; } std::chrono::seconds CConnman::GetMaxOutboundTimeLeftInCycle() { LOCK(cs_totalBytesSent); 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(); return (cycleEndTime < now) ? 0s : cycleEndTime - now; } bool CConnman::OutboundTargetReached(bool historicalBlockServingLimit) { LOCK(cs_totalBytesSent); 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() { LOCK(cs_totalBytesSent); if (nMaxOutboundLimit == 0) return 0; return (nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit) ? 0 : nMaxOutboundLimit - nMaxOutboundTotalBytesSentInCycle; } uint64_t CConnman::GetTotalBytesRecv() { LOCK(cs_totalBytesRecv); return nTotalBytesRecv; } uint64_t CConnman::GetTotalBytesSent() { LOCK(cs_totalBytesSent); return nTotalBytesSent; } ServiceFlags CConnman::GetLocalServices() const { return nLocalServices; } unsigned int CConnman::GetReceiveFloodSize() const { return nReceiveFloodSize; } CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, SOCKET hSocketIn, const CAddress& addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const CAddress& addrBindIn, const std::string& addrNameIn, ConnectionType conn_type_in, bool inbound_onion) : nTimeConnected(GetSystemTimeInSeconds()), addr(addrIn), addrBind(addrBindIn), nKeyedNetGroup(nKeyedNetGroupIn), id(idIn), nLocalHostNonce(nLocalHostNonceIn), m_conn_type(conn_type_in), nLocalServices(nLocalServicesIn), m_inbound_onion(inbound_onion) { if (inbound_onion) assert(conn_type_in == ConnectionType::INBOUND); hSocket = hSocketIn; addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn; if (conn_type_in != ConnectionType::BLOCK_RELAY) { m_tx_relay = MakeUnique(); } if (RelayAddrsWithConn()) { m_addr_known = MakeUnique(5000, 0.001); } for (const std::string &msg : getAllNetMessageTypes()) mapRecvBytesPerMsgCmd[msg] = 0; mapRecvBytesPerMsgCmd[NET_MESSAGE_COMMAND_OTHER] = 0; if (fLogIPs) { LogPrint(BCLog::NET, "Added connection to %s peer=%d\n", addrName, id); } else { LogPrint(BCLog::NET, "Added connection peer=%d\n", id); } m_deserializer = MakeUnique(V1TransportDeserializer(Params(), GetId(), SER_NETWORK, INIT_PROTO_VERSION)); m_serializer = MakeUnique(V1TransportSerializer()); } CNode::~CNode() { CloseSocket(hSocket); } bool CConnman::NodeFullyConnected(const CNode* pnode) { return pnode && pnode->fSuccessfullyConnected && !pnode->fDisconnect; } void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg) { size_t nMessageSize = msg.data.size(); LogPrint(BCLog::NET, "sending %s (%d bytes) peer=%d\n", SanitizeString(msg.m_type), nMessageSize, pnode->GetId()); // make sure we use the appropriate network transport format std::vector serializedHeader; pnode->m_serializer->prepareForTransport(msg, serializedHeader); size_t nTotalSize = nMessageSize + serializedHeader.size(); size_t nBytesSent = 0; { LOCK(pnode->cs_vSend); bool optimisticSend(pnode->vSendMsg.empty()); //log total amount of bytes per message type pnode->mapSendBytesPerMsgCmd[msg.m_type] += nTotalSize; pnode->nSendSize += nTotalSize; if (pnode->nSendSize > nSendBufferMaxSize) pnode->fPauseSend = true; pnode->vSendMsg.push_back(std::move(serializedHeader)); if (nMessageSize) pnode->vSendMsg.push_back(std::move(msg.data)); // If write queue empty, attempt "optimistic write" if (optimisticSend == true) nBytesSent = SocketSendData(*pnode); } if (nBytesSent) RecordBytesSent(nBytesSent); } bool CConnman::ForNode(NodeId id, std::function func) { CNode* found = nullptr; LOCK(cs_vNodes); for (auto&& pnode : vNodes) { if(pnode->GetId() == id) { found = pnode; break; } } return found != nullptr && NodeFullyConnected(found) && func(found); } int64_t CConnman::PoissonNextSendInbound(int64_t now, int average_interval_seconds) { if (m_next_send_inv_to_incoming < now) { // If this function were called from multiple threads simultaneously // it would possible that both update the next send variable, and return a different result to their caller. // This is not possible in practice as only the net processing thread invokes this function. m_next_send_inv_to_incoming = PoissonNextSend(now, average_interval_seconds); } return m_next_send_inv_to_incoming; } int64_t PoissonNextSend(int64_t now, int average_interval_seconds) { return now + (int64_t)(log1p(GetRand(1ULL << 48) * -0.0000000000000035527136788 /* -1/2^48 */) * average_interval_seconds * -1000000.0 + 0.5); } CSipHasher CConnman::GetDeterministicRandomizer(uint64_t id) const { return CSipHasher(nSeed0, nSeed1).Write(id); } uint64_t CConnman::CalculateKeyedNetGroup(const CAddress& ad) const { std::vector vchNetGroup(ad.GetGroup(addrman.m_asmap)); return GetDeterministicRandomizer(RANDOMIZER_ID_NETGROUP).Write(vchNetGroup.data(), vchNetGroup.size()).Finalize(); }