mirror of https://github.com/bitcoin/bitcoin
net: attempts to connect to all resolved addresses when connecting to a node
Prior to this, when establishing a network connection via CConnman::ConnectNode, if the connection needed address resolution, a single address would be picked at random from the resolved addresses and our node will try to connect to it. However, this would lead to the behavior of ConnectNode being unpredictable when the address was resolved to various ips (e.g. the address resolving to IPv4 and IPv6, but we only support one of them). This patches the aforementioned behavior by going over all resolved IPs until we find one we can connect to or until we exhaust them.
This commit is contained in:
Sergi Delgado Segura
parent
2ffaa92702
commit
fd81a37239
174
src/net.cpp
174
src/net.cpp
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@ -412,6 +412,9 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
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// Resolve
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const uint16_t default_port{pszDest != nullptr ? GetDefaultPort(pszDest) :
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m_params.GetDefaultPort()};
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// Collection of addresses to try to connect to: either all dns resolved addresses if a domain name (pszDest) is provided, or addrConnect otherwise.
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std::vector<CAddress> connect_to{};
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if (pszDest) {
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std::vector<CService> resolved{Lookup(pszDest, default_port, fNameLookup && !HaveNameProxy(), 256)};
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if (!resolved.empty()) {
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@ -432,8 +435,16 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
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LogPrintf("Not opening a connection to %s, already connected to %s\n", pszDest, addrConnect.ToStringAddrPort());
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return nullptr;
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}
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// Add the address to the resolved addresses vector so we can try to connect to it later on
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connect_to.push_back(addrConnect);
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}
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} else {
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// For resolution via proxy
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connect_to.push_back(addrConnect);
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}
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} else {
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// Connect via addrConnect directly
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connect_to.push_back(addrConnect);
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}
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// Connect
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@ -443,94 +454,99 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
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assert(!addr_bind.IsValid());
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std::unique_ptr<i2p::sam::Session> i2p_transient_session;
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if (addrConnect.IsValid()) {
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const bool use_proxy{GetProxy(addrConnect.GetNetwork(), proxy)};
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bool proxyConnectionFailed = false;
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for (auto& target_addr: connect_to) {
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if (target_addr.IsValid()) {
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const bool use_proxy{GetProxy(target_addr.GetNetwork(), proxy)};
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bool proxyConnectionFailed = false;
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if (addrConnect.IsI2P() && use_proxy) {
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i2p::Connection conn;
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bool connected{false};
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if (target_addr.IsI2P() && use_proxy) {
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i2p::Connection conn;
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bool connected{false};
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if (m_i2p_sam_session) {
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connected = m_i2p_sam_session->Connect(addrConnect, conn, proxyConnectionFailed);
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if (m_i2p_sam_session) {
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connected = m_i2p_sam_session->Connect(target_addr, conn, proxyConnectionFailed);
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} else {
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{
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LOCK(m_unused_i2p_sessions_mutex);
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if (m_unused_i2p_sessions.empty()) {
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i2p_transient_session =
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std::make_unique<i2p::sam::Session>(proxy, &interruptNet);
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} else {
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i2p_transient_session.swap(m_unused_i2p_sessions.front());
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m_unused_i2p_sessions.pop();
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}
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}
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connected = i2p_transient_session->Connect(target_addr, conn, proxyConnectionFailed);
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if (!connected) {
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LOCK(m_unused_i2p_sessions_mutex);
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if (m_unused_i2p_sessions.size() < MAX_UNUSED_I2P_SESSIONS_SIZE) {
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m_unused_i2p_sessions.emplace(i2p_transient_session.release());
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}
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}
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}
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if (connected) {
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sock = std::move(conn.sock);
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addr_bind = CAddress{conn.me, NODE_NONE};
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}
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} else if (use_proxy) {
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LogPrintLevel(BCLog::PROXY, BCLog::Level::Debug, "Using proxy: %s to connect to %s\n", proxy.ToString(), target_addr.ToStringAddrPort());
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sock = ConnectThroughProxy(proxy, target_addr.ToStringAddr(), target_addr.GetPort(), proxyConnectionFailed);
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} else {
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{
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LOCK(m_unused_i2p_sessions_mutex);
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if (m_unused_i2p_sessions.empty()) {
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i2p_transient_session =
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std::make_unique<i2p::sam::Session>(proxy, &interruptNet);
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} else {
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i2p_transient_session.swap(m_unused_i2p_sessions.front());
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m_unused_i2p_sessions.pop();
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}
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}
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connected = i2p_transient_session->Connect(addrConnect, conn, proxyConnectionFailed);
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if (!connected) {
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LOCK(m_unused_i2p_sessions_mutex);
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if (m_unused_i2p_sessions.size() < MAX_UNUSED_I2P_SESSIONS_SIZE) {
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m_unused_i2p_sessions.emplace(i2p_transient_session.release());
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}
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}
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// no proxy needed (none set for target network)
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sock = ConnectDirectly(target_addr, conn_type == ConnectionType::MANUAL);
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}
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if (connected) {
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sock = std::move(conn.sock);
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addr_bind = CAddress{conn.me, NODE_NONE};
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if (!proxyConnectionFailed) {
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// If a connection to the node was attempted, and failure (if any) is not caused by a problem connecting to
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// the proxy, mark this as an attempt.
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addrman.Attempt(target_addr, fCountFailure);
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}
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} else if (use_proxy) {
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LogPrintLevel(BCLog::PROXY, BCLog::Level::Debug, "Using proxy: %s to connect to %s:%s\n", proxy.ToString(), addrConnect.ToStringAddr(), addrConnect.GetPort());
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sock = ConnectThroughProxy(proxy, addrConnect.ToStringAddr(), addrConnect.GetPort(), proxyConnectionFailed);
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} else {
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// no proxy needed (none set for target network)
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sock = ConnectDirectly(addrConnect, conn_type == ConnectionType::MANUAL);
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} else if (pszDest && GetNameProxy(proxy)) {
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std::string host;
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uint16_t port{default_port};
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SplitHostPort(std::string(pszDest), port, host);
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bool proxyConnectionFailed;
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sock = ConnectThroughProxy(proxy, host, port, proxyConnectionFailed);
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}
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if (!proxyConnectionFailed) {
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// If a connection to the node was attempted, and failure (if any) is not caused by a problem connecting to
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// the proxy, mark this as an attempt.
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addrman.Attempt(addrConnect, fCountFailure);
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// Check any other resolved address (if any) if we fail to connect
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if (!sock) {
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continue;
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}
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} else if (pszDest && GetNameProxy(proxy)) {
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std::string host;
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uint16_t port{default_port};
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SplitHostPort(std::string(pszDest), port, host);
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bool proxyConnectionFailed;
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sock = ConnectThroughProxy(proxy, host, port, proxyConnectionFailed);
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}
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if (!sock) {
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return nullptr;
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NetPermissionFlags permission_flags = NetPermissionFlags::None;
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std::vector<NetWhitelistPermissions> whitelist_permissions = conn_type == ConnectionType::MANUAL ? vWhitelistedRangeOutgoing : std::vector<NetWhitelistPermissions>{};
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AddWhitelistPermissionFlags(permission_flags, target_addr, whitelist_permissions);
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// Add node
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NodeId id = GetNewNodeId();
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uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
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if (!addr_bind.IsValid()) {
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addr_bind = GetBindAddress(*sock);
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}
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CNode* pnode = new CNode(id,
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std::move(sock),
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target_addr,
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CalculateKeyedNetGroup(target_addr),
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nonce,
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addr_bind,
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pszDest ? pszDest : "",
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conn_type,
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/*inbound_onion=*/false,
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CNodeOptions{
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.permission_flags = permission_flags,
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.i2p_sam_session = std::move(i2p_transient_session),
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.recv_flood_size = nReceiveFloodSize,
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.use_v2transport = use_v2transport,
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});
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pnode->AddRef();
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// We're making a new connection, harvest entropy from the time (and our peer count)
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RandAddEvent((uint32_t)id);
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return pnode;
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}
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NetPermissionFlags permission_flags = NetPermissionFlags::None;
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std::vector<NetWhitelistPermissions> whitelist_permissions = conn_type == ConnectionType::MANUAL ? vWhitelistedRangeOutgoing : std::vector<NetWhitelistPermissions>{};
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AddWhitelistPermissionFlags(permission_flags, addrConnect, whitelist_permissions);
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// Add node
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NodeId id = GetNewNodeId();
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uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
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if (!addr_bind.IsValid()) {
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addr_bind = GetBindAddress(*sock);
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}
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CNode* pnode = new CNode(id,
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std::move(sock),
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addrConnect,
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CalculateKeyedNetGroup(addrConnect),
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nonce,
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addr_bind,
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pszDest ? pszDest : "",
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conn_type,
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/*inbound_onion=*/false,
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CNodeOptions{
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.permission_flags = permission_flags,
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.i2p_sam_session = std::move(i2p_transient_session),
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.recv_flood_size = nReceiveFloodSize,
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.use_v2transport = use_v2transport,
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});
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pnode->AddRef();
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// We're making a new connection, harvest entropy from the time (and our peer count)
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RandAddEvent((uint32_t)id);
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return pnode;
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return nullptr;
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}
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void CNode::CloseSocketDisconnect()
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