Discovery ENR extension - server part

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [1.7.0] - Unreleased
 
 - Added: [#5537](https://github.com/ethereum/aleth/pull/5537) Creating Ethereum Node Record (ENR) at program start.
+- Added: [#5571](https://github.com/ethereum/aleth/pull/5571) Support Discovery v4 ENR Extension messages.
 - Added: [#5557](https://github.com/ethereum/aleth/pull/5557) Improved debug logging of full sync.
 - Added: [#5564](https://github.com/ethereum/aleth/pull/5564) Improved help output of Aleth by adding list of channels.
 - Added: [#5575](https://github.com/ethereum/aleth/pull/5575) Log active peer count and peer list every 30 seconds.

aleth/main.cpp

@@ -110,7 +110,7 @@ int main(int argc, char** argv)
     setDefaultOrCLocale();
 
     // Init secp256k1 context by calling one of the functions.
-    toPublic({});
+    toPublic(Secret{});
 
     // Init defaults
     Ethash::init();

libdevcrypto/Common.cpp

@@ -89,6 +89,26 @@ Public dev::toPublic(Secret const& _secret)
     return Public{&serializedPubkey[1], Public::ConstructFromPointer};
 }
 
+Public dev::toPublic(PublicCompressed const& _publicCompressed)
+{
+    auto* ctx = getCtx();
+
+    secp256k1_pubkey rawPubkey;
+    if (!secp256k1_ec_pubkey_parse(
+            ctx, &rawPubkey, _publicCompressed.data(), PublicCompressed::size))
+        return {};
+
+    std::array<byte, 65> serializedPubkey;
+    auto serializedPubkeySize = serializedPubkey.size();
+    secp256k1_ec_pubkey_serialize(
+        ctx, serializedPubkey.data(), &serializedPubkeySize, &rawPubkey, SECP256K1_EC_UNCOMPRESSED);
+    assert(serializedPubkeySize == serializedPubkey.size());
+    // Expect single byte header of value 0x04 -- uncompressed public key.
+    assert(serializedPubkey[0] == 0x04);
+    // Create the Public skipping the header.
+    return Public{&serializedPubkey[1], Public::ConstructFromPointer};
+}
+
 PublicCompressed dev::toPublicCompressed(Secret const& _secret)
 {
     PublicCompressed serializedPubkey;

libdevcrypto/Common.h

@@ -68,6 +68,9 @@ using Secrets = std::vector<Secret>;
 /// Convert a secret key into the public key equivalent.
 Public toPublic(Secret const& _secret);
 
+/// Convert a compressed public key into the uncompressed equivalent.
+Public toPublic(PublicCompressed const& _publicCompressed);
+
 /// Convert a secret key into the public key in compressed format.
 PublicCompressed toPublicCompressed(Secret const& _secret);
 

libp2p/Host.cpp

@@ -800,13 +800,9 @@ void Host::startedWorking()
         m_listenPort = m_netConfig.listenPort;
 
     determinePublic();
-    auto nodeTable = make_shared<NodeTable>(
-        m_ioService,
-        m_alias,
+    auto nodeTable = make_shared<NodeTable>(m_ioService, m_alias,
         NodeIPEndpoint(bi::address::from_string(listenAddress()), listenPort(), listenPort()),
-        m_netConfig.discovery,
-        m_netConfig.allowLocalDiscovery
-    );
+        m_enr, m_netConfig.discovery, m_netConfig.allowLocalDiscovery);
 
     // Don't set an event handler if we don't have capabilities, because no capabilities
     // means there's no host state to update in response to node table events

libp2p/NodeTable.cpp

@@ -32,9 +32,10 @@ inline bool operator==(weak_ptr<NodeEntry> const& _weak, shared_ptr<NodeEntry> c
 }
 
 NodeTable::NodeTable(ba::io_service& _io, KeyPair const& _alias, NodeIPEndpoint const& _endpoint,
-    bool _enabled, bool _allowLocalDiscovery)
+    ENR const& _enr, bool _enabled, bool _allowLocalDiscovery)
   : m_hostNodeID{_alias.pub()},
     m_hostNodeEndpoint{_endpoint},
+    m_hostENR{_enr},
     m_secret{_alias.secret()},
     m_socket{make_shared<NodeSocket>(
         _io, static_cast<UDPSocketEvents&>(*this), (bi::udp::endpoint)m_hostNodeEndpoint)},
@@ -220,7 +221,7 @@ void NodeTable::doDiscoveryRound(
             }
 
             FindNode p(nodeEntry->endpoint(), _node);
-            p.ts = nextRequestExpirationTime();
+            p.timestamp = nextRequestExpirationTime();
             p.sign(m_secret);
             m_sentFindNodes.emplace_back(nodeEntry->id(), chrono::steady_clock::now());
             LOG(m_logger) << p.typeName() << " to " << nodeEntry->node << " (target: " << _node
@@ -302,7 +303,8 @@ void NodeTable::ping(Node const& _node, shared_ptr<NodeEntry> _replacementNodeEn
     }
 
     PingNode p{m_hostNodeEndpoint, _node.endpoint};
-    p.ts = nextRequestExpirationTime();
+    p.timestamp = nextRequestExpirationTime();
+    p.seq = m_hostENR.sequenceNumber();
     auto const pingHash = p.sign(m_secret);
     LOG(m_logger) << p.typeName() << " to " << _node;
     m_socket->send(p);
@@ -454,6 +456,14 @@ void NodeTable::onPacketReceived(
         case PingNode::type:
             sourceNodeEntry = handlePingNode(_from, *packet);
             break;
+
+        case ENRRequest::type:
+            sourceNodeEntry = handleENRRequest(_from, *packet);
+            break;
+
+        case ENRResponse::type:
+            sourceNodeEntry = handleENRResponse(_from, *packet);
+            break;
         }
 
         if (sourceNodeEntry)
@@ -608,7 +618,7 @@ std::shared_ptr<NodeEntry> NodeTable::handleFindNode(
     for (unsigned offset = 0; offset < nearest.size(); offset += nlimit)
     {
         Neighbours out(_from, nearest, offset, nlimit);
-        out.ts = nextRequestExpirationTime();
+        out.timestamp = nextRequestExpirationTime();
         LOG(m_logger) << out.typeName() << " to " << in.sourceid << "@" << _from;
         out.sign(m_secret);
         if (out.data.size() > 1280)
@@ -631,8 +641,9 @@ std::shared_ptr<NodeEntry> NodeTable::handlePingNode(
     // Send PONG response.
     Pong p(sourceEndpoint);
     LOG(m_logger) << p.typeName() << " to " << in.sourceid << "@" << _from;
-    p.ts = nextRequestExpirationTime();
+    p.timestamp = nextRequestExpirationTime();
     p.echo = in.echo;
+    p.seq = m_hostENR.sequenceNumber();
     p.sign(m_secret);
     m_socket->send(p);
 
@@ -647,6 +658,69 @@ std::shared_ptr<NodeEntry> NodeTable::handlePingNode(
     return sourceNodeEntry;
 }
 
+std::shared_ptr<NodeEntry> NodeTable::handleENRRequest(
+    bi::udp::endpoint const& _from, DiscoveryDatagram const& _packet)
+{
+    std::shared_ptr<NodeEntry> sourceNodeEntry = nodeEntry(_packet.sourceid);
+    if (!sourceNodeEntry)
+    {
+        LOG(m_logger) << "Source node (" << _packet.sourceid << "@" << _from
+                      << ") not found in node table. Ignoring ENRRequest request.";
+        return {};
+    }
+    if (sourceNodeEntry->endpoint() != _from)
+    {
+        LOG(m_logger) << "ENRRequest packet from unexpected endpoint " << _from << " instead of "
+                      << sourceNodeEntry->endpoint();
+        return {};
+    }
+    if (!sourceNodeEntry->lastPongReceivedTime)
+    {
+        LOG(m_logger) << "Unexpected ENRRequest packet! Endpoint proof hasn't been performed yet.";
+        return {};
+    }
+    if (!sourceNodeEntry->hasValidEndpointProof())
+    {
+        LOG(m_logger) << "Unexpected ENRRequest packet! Endpoint proof has expired.";
+        return {};
+    }
+
+    auto const& in = dynamic_cast<ENRRequest const&>(_packet);
+
+    ENRResponse response{_from, m_hostENR};
+    LOG(m_logger) << response.typeName() << " to " << in.sourceid << "@" << _from;
+    response.timestamp = nextRequestExpirationTime();
+    response.echo = in.echo;
+    response.sign(m_secret);
+    m_socket->send(response);
+
+    return sourceNodeEntry;
+}
+
+std::shared_ptr<NodeEntry> NodeTable::handleENRResponse(
+    bi::udp::endpoint const& _from, DiscoveryDatagram const& _packet)
+{
+    std::shared_ptr<NodeEntry> sourceNodeEntry = nodeEntry(_packet.sourceid);
+    if (!sourceNodeEntry)
+    {
+        LOG(m_logger) << "Source node (" << _packet.sourceid << "@" << _from
+                      << ") not found in node table. Ignoring ENRResponse packet.";
+        return {};
+    }
+    if (sourceNodeEntry->endpoint() != _from)
+    {
+        LOG(m_logger) << "ENRResponse packet from unexpected endpoint " << _from << " instead of "
+                      << sourceNodeEntry->endpoint();
+        return {};
+    }
+
+    auto const& in = dynamic_cast<ENRResponse const&>(_packet);
+    LOG(m_logger) << "Received ENR: " << *in.enr;
+
+    return sourceNodeEntry;
+}
+
+
 void NodeTable::doDiscovery()
 {
     m_discoveryTimer->expires_from_now(c_bucketRefreshMs);
@@ -766,6 +840,12 @@ unique_ptr<DiscoveryDatagram> DiscoveryDatagram::interpretUDP(bi::udp::endpoint
     case Neighbours::type:
         decoded.reset(new Neighbours(_from, sourceid, echo));
         break;
+    case ENRRequest::type:
+        decoded.reset(new ENRRequest(_from, sourceid, echo));
+        break;
+    case ENRResponse::type:
+        decoded.reset(new ENRResponse(_from, sourceid, echo));
+        break;
     default:
         LOG(g_discoveryWarnLogger::get()) << "Invalid packet (unknown packet type) from "
                                           << _from.address().to_string() << ":" << _from.port();