all: new p2p node representation (#17643)

Package p2p/enode provides a generalized representation of p2p nodes
which can contain arbitrary information in key/value pairs. It is also
the new home for the node database. The "v4" identity scheme is also
moved here from p2p/enr to remove the dependency on Ethereum crypto from
that package.

Record signature handling is changed significantly. The identity scheme
registry is removed and acceptable schemes must be passed to any method
that needs identity. This means records must now be validated explicitly
after decoding.

The enode API is designed to make signature handling easy and safe: most
APIs around the codebase work with enode.Node, which is a wrapper around
a valid record. Going from enr.Record to enode.Node requires a valid
signature.

* p2p/discover: port to p2p/enode

This ports the discovery code to the new node representation in
p2p/enode. The wire protocol is unchanged, this can be considered a
refactoring change. The Kademlia table can now deal with nodes using an
arbitrary identity scheme. This requires a few incompatible API changes:

  - Table.Lookup is not available anymore. It used to take a public key
    as argument because v4 protocol requires one. Its replacement is
    LookupRandom.
  - Table.Resolve takes *enode.Node instead of NodeID. This is also for
    v4 protocol compatibility because nodes cannot be looked up by ID
    alone.
  - Types Node and NodeID are gone. Further commits in the series will be
    fixes all over the the codebase to deal with those removals.

* p2p: port to p2p/enode and discovery changes

This adapts package p2p to the changes in p2p/discover. All uses of
discover.Node and discover.NodeID are replaced by their equivalents from
p2p/enode.

New API is added to retrieve the enode.Node instance of a peer. The
behavior of Server.Self with discovery disabled is improved. It now
tries much harder to report a working IP address, falling back to
127.0.0.1 if no suitable address can be determined through other means.
These changes were needed for tests of other packages later in the
series.

* p2p/simulations, p2p/testing: port to p2p/enode

No surprises here, mostly replacements of discover.Node, discover.NodeID
with their new equivalents. The 'interesting' API changes are:

 - testing.ProtocolSession tracks complete nodes, not just their IDs.
 - adapters.NodeConfig has a new method to create a complete node.

These changes were needed to make swarm tests work.

Note that the NodeID change makes the code incompatible with old
simulation snapshots.

* whisper/whisperv5, whisper/whisperv6: port to p2p/enode

This port was easy because whisper uses []byte for node IDs and
URL strings in the API.

* eth: port to p2p/enode

Again, easy to port because eth uses strings for node IDs and doesn't
care about node information in any way.

* les: port to p2p/enode

Apart from replacing discover.NodeID with enode.ID, most changes are in
the server pool code. It now deals with complete nodes instead
of (Pubkey, IP, Port) triples. The database format is unchanged for now,
but we should probably change it to use the node database later.

* node: port to p2p/enode

This change simply replaces discover.Node and discover.NodeID with their
new equivalents.

* swarm/network: port to p2p/enode

Swarm has its own node address representation, BzzAddr, containing both
an overlay address (the hash of a secp256k1 public key) and an underlay
address (enode:// URL).

There are no changes to the BzzAddr format in this commit, but certain
operations such as creating a BzzAddr from a node ID are now impossible
because node IDs aren't public keys anymore.

Most swarm-related changes in the series remove uses of
NewAddrFromNodeID, replacing it with NewAddr which takes a complete node
as argument. ToOverlayAddr is removed because we can just use the node
ID directly.

1 files changed, 72 insertions, 50 deletions

diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
index 0ff47c5e4..45fcce282 100644
--- a/p2p/discover/udp.go
+++ b/p2p/discover/udp.go
@@ -27,6 +27,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -46,8 +47,9 @@ var (
 
 // Timeouts
 const (
-	respTimeout = 500 * time.Millisecond
-	expiration  = 20 * time.Second
+	respTimeout    = 500 * time.Millisecond
+	expiration     = 20 * time.Second
+	bondExpiration = 24 * time.Hour
 
 	ntpFailureThreshold = 32               // Continuous timeouts after which to check NTP
 	ntpWarningCooldown  = 10 * time.Minute // Minimum amount of time to pass before repeating NTP warning
@@ -87,7 +89,7 @@ type (
 
 	// findnode is a query for nodes close to the given target.
 	findnode struct {
-		Target     NodeID // doesn't need to be an actual public key
+		Target     encPubkey
 		Expiration uint64
 		// Ignore additional fields (for forward compatibility).
 		Rest []rlp.RawValue `rlp:"tail"`
@@ -105,7 +107,7 @@ type (
 		IP  net.IP // len 4 for IPv4 or 16 for IPv6
 		UDP uint16 // for discovery protocol
 		TCP uint16 // for RLPx protocol
-		ID  NodeID
+		ID  encPubkey
 	}
 
 	rpcEndpoint struct {
@@ -123,7 +125,7 @@ func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
 	return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
 }
 
-func (t *udp) nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*Node, error) {
+func (t *udp) nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*node, error) {
 	if rn.UDP <= 1024 {
 		return nil, errors.New("low port")
 	}
@@ -133,17 +135,26 @@ func (t *udp) nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*Node, error) {
 	if t.netrestrict != nil && !t.netrestrict.Contains(rn.IP) {
 		return nil, errors.New("not contained in netrestrict whitelist")
 	}
-	n := NewNode(rn.ID, rn.IP, rn.UDP, rn.TCP)
-	err := n.validateComplete()
+	key, err := decodePubkey(rn.ID)
+	if err != nil {
+		return nil, err
+	}
+	n := wrapNode(enode.NewV4(key, rn.IP, int(rn.TCP), int(rn.UDP)))
+	err = n.ValidateComplete()
 	return n, err
 }
 
-func nodeToRPC(n *Node) rpcNode {
-	return rpcNode{ID: n.ID, IP: n.IP, UDP: n.UDP, TCP: n.TCP}
+func nodeToRPC(n *node) rpcNode {
+	var key ecdsa.PublicKey
+	var ekey encPubkey
+	if err := n.Load((*enode.Secp256k1)(&key)); err == nil {
+		ekey = encodePubkey(&key)
+	}
+	return rpcNode{ID: ekey, IP: n.IP(), UDP: uint16(n.UDP()), TCP: uint16(n.TCP())}
 }
 
 type packet interface {
-	handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error
+	handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error
 	name() string
 }
 
@@ -181,7 +192,7 @@ type udp struct {
 // to all the callback functions for that node.
 type pending struct {
 	// these fields must match in the reply.
-	from  NodeID
+	from  enode.ID
 	ptype byte
 
 	// time when the request must complete
@@ -199,7 +210,7 @@ type pending struct {
 }
 
 type reply struct {
-	from  NodeID
+	from  enode.ID
 	ptype byte
 	data  interface{}
 	// loop indicates whether there was
@@ -222,7 +233,7 @@ type Config struct {
 	AnnounceAddr *net.UDPAddr      // local address announced in the DHT
 	NodeDBPath   string            // if set, the node database is stored at this filesystem location
 	NetRestrict  *netutil.Netlist  // network whitelist
-	Bootnodes    []*Node           // list of bootstrap nodes
+	Bootnodes    []*enode.Node     // list of bootstrap nodes
 	Unhandled    chan<- ReadPacket // unhandled packets are sent on this channel
 }
 
@@ -237,6 +248,16 @@ func ListenUDP(c conn, cfg Config) (*Table, error) {
 }
 
 func newUDP(c conn, cfg Config) (*Table, *udp, error) {
+	realaddr := c.LocalAddr().(*net.UDPAddr)
+	if cfg.AnnounceAddr != nil {
+		realaddr = cfg.AnnounceAddr
+	}
+	self := enode.NewV4(&cfg.PrivateKey.PublicKey, realaddr.IP, realaddr.Port, realaddr.Port)
+	db, err := enode.OpenDB(cfg.NodeDBPath)
+	if err != nil {
+		return nil, nil, err
+	}
+
 	udp := &udp{
 		conn:        c,
 		priv:        cfg.PrivateKey,
@@ -245,13 +266,9 @@ func newUDP(c conn, cfg Config) (*Table, *udp, error) {
 		gotreply:    make(chan reply),
 		addpending:  make(chan *pending),
 	}
-	realaddr := c.LocalAddr().(*net.UDPAddr)
-	if cfg.AnnounceAddr != nil {
-		realaddr = cfg.AnnounceAddr
-	}
 	// TODO: separate TCP port
 	udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
-	tab, err := newTable(udp, PubkeyID(&cfg.PrivateKey.PublicKey), realaddr, cfg.NodeDBPath, cfg.Bootnodes)
+	tab, err := newTable(udp, self, db, cfg.Bootnodes)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -265,17 +282,18 @@ func newUDP(c conn, cfg Config) (*Table, *udp, error) {
 func (t *udp) close() {
 	close(t.closing)
 	t.conn.Close()
+	t.db.Close()
 	// TODO: wait for the loops to end.
 }
 
 // ping sends a ping message to the given node and waits for a reply.
-func (t *udp) ping(toid NodeID, toaddr *net.UDPAddr) error {
+func (t *udp) ping(toid enode.ID, toaddr *net.UDPAddr) error {
 	return <-t.sendPing(toid, toaddr, nil)
 }
 
 // sendPing sends a ping message to the given node and invokes the callback
 // when the reply arrives.
-func (t *udp) sendPing(toid NodeID, toaddr *net.UDPAddr, callback func()) <-chan error {
+func (t *udp) sendPing(toid enode.ID, toaddr *net.UDPAddr, callback func()) <-chan error {
 	req := &ping{
 		Version:    4,
 		From:       t.ourEndpoint,
@@ -299,21 +317,21 @@ func (t *udp) sendPing(toid NodeID, toaddr *net.UDPAddr, callback func()) <-chan
 	return errc
 }
 
-func (t *udp) waitping(from NodeID) error {
+func (t *udp) waitping(from enode.ID) error {
 	return <-t.pending(from, pingPacket, func(interface{}) bool { return true })
 }
 
 // findnode sends a findnode request to the given node and waits until
 // the node has sent up to k neighbors.
-func (t *udp) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
+func (t *udp) findnode(toid enode.ID, toaddr *net.UDPAddr, target encPubkey) ([]*node, error) {
 	// If we haven't seen a ping from the destination node for a while, it won't remember
 	// our endpoint proof and reject findnode. Solicit a ping first.
-	if time.Since(t.db.lastPingReceived(toid)) > nodeDBNodeExpiration {
+	if time.Since(t.db.LastPingReceived(toid)) > bondExpiration {
 		t.ping(toid, toaddr)
 		t.waitping(toid)
 	}
 
-	nodes := make([]*Node, 0, bucketSize)
+	nodes := make([]*node, 0, bucketSize)
 	nreceived := 0
 	errc := t.pending(toid, neighborsPacket, func(r interface{}) bool {
 		reply := r.(*neighbors)
@@ -337,7 +355,7 @@ func (t *udp) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node
 
 // pending adds a reply callback to the pending reply queue.
 // see the documentation of type pending for a detailed explanation.
-func (t *udp) pending(id NodeID, ptype byte, callback func(interface{}) bool) <-chan error {
+func (t *udp) pending(id enode.ID, ptype byte, callback func(interface{}) bool) <-chan error {
 	ch := make(chan error, 1)
 	p := &pending{from: id, ptype: ptype, callback: callback, errc: ch}
 	select {
@@ -349,7 +367,7 @@ func (t *udp) pending(id NodeID, ptype byte, callback func(interface{}) bool) <-
 	return ch
 }
 
-func (t *udp) handleReply(from NodeID, ptype byte, req packet) bool {
+func (t *udp) handleReply(from enode.ID, ptype byte, req packet) bool {
 	matched := make(chan bool, 1)
 	select {
 	case t.gotreply <- reply{from, ptype, req, matched}:
@@ -563,19 +581,20 @@ func (t *udp) handlePacket(from *net.UDPAddr, buf []byte) error {
 	return err
 }
 
-func decodePacket(buf []byte) (packet, NodeID, []byte, error) {
+func decodePacket(buf []byte) (packet, encPubkey, []byte, error) {
 	if len(buf) < headSize+1 {
-		return nil, NodeID{}, nil, errPacketTooSmall
+		return nil, encPubkey{}, nil, errPacketTooSmall
 	}
 	hash, sig, sigdata := buf[:macSize], buf[macSize:headSize], buf[headSize:]
 	shouldhash := crypto.Keccak256(buf[macSize:])
 	if !bytes.Equal(hash, shouldhash) {
-		return nil, NodeID{}, nil, errBadHash
+		return nil, encPubkey{}, nil, errBadHash
 	}
-	fromID, err := recoverNodeID(crypto.Keccak256(buf[headSize:]), sig)
+	fromKey, err := recoverNodeKey(crypto.Keccak256(buf[headSize:]), sig)
 	if err != nil {
-		return nil, NodeID{}, hash, err
+		return nil, fromKey, hash, err
 	}
+
 	var req packet
 	switch ptype := sigdata[0]; ptype {
 	case pingPacket:
@@ -587,56 +606,59 @@ func decodePacket(buf []byte) (packet, NodeID, []byte, error) {
 	case neighborsPacket:
 		req = new(neighbors)
 	default:
-		return nil, fromID, hash, fmt.Errorf("unknown type: %d", ptype)
+		return nil, fromKey, hash, fmt.Errorf("unknown type: %d", ptype)
 	}
 	s := rlp.NewStream(bytes.NewReader(sigdata[1:]), 0)
 	err = s.Decode(req)
-	return req, fromID, hash, err
+	return req, fromKey, hash, err
 }
 
-func (req *ping) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error {
+func (req *ping) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
 	if expired(req.Expiration) {
 		return errExpired
 	}
+	key, err := decodePubkey(fromKey)
+	if err != nil {
+		return fmt.Errorf("invalid public key: %v", err)
+	}
 	t.send(from, pongPacket, &pong{
 		To:         makeEndpoint(from, req.From.TCP),
 		ReplyTok:   mac,
 		Expiration: uint64(time.Now().Add(expiration).Unix()),
 	})
-	t.handleReply(fromID, pingPacket, req)
-
-	// Add the node to the table. Before doing so, ensure that we have a recent enough pong
-	// recorded in the database so their findnode requests will be accepted later.
-	n := NewNode(fromID, from.IP, uint16(from.Port), req.From.TCP)
-	if time.Since(t.db.lastPongReceived(fromID)) > nodeDBNodeExpiration {
-		t.sendPing(fromID, from, func() { t.addThroughPing(n) })
+	n := wrapNode(enode.NewV4(key, from.IP, int(req.From.TCP), from.Port))
+	t.handleReply(n.ID(), pingPacket, req)
+	if time.Since(t.db.LastPongReceived(n.ID())) > bondExpiration {
+		t.sendPing(n.ID(), from, func() { t.addThroughPing(n) })
 	} else {
 		t.addThroughPing(n)
 	}
-	t.db.updateLastPingReceived(fromID, time.Now())
+	t.db.UpdateLastPingReceived(n.ID(), time.Now())
 	return nil
 }
 
 func (req *ping) name() string { return "PING/v4" }
 
-func (req *pong) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error {
+func (req *pong) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
 	if expired(req.Expiration) {
 		return errExpired
 	}
+	fromID := fromKey.id()
 	if !t.handleReply(fromID, pongPacket, req) {
 		return errUnsolicitedReply
 	}
-	t.db.updateLastPongReceived(fromID, time.Now())
+	t.db.UpdateLastPongReceived(fromID, time.Now())
 	return nil
 }
 
 func (req *pong) name() string { return "PONG/v4" }
 
-func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error {
+func (req *findnode) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
 	if expired(req.Expiration) {
 		return errExpired
 	}
-	if !t.db.hasBond(fromID) {
+	fromID := fromKey.id()
+	if time.Since(t.db.LastPongReceived(fromID)) > bondExpiration {
 		// No endpoint proof pong exists, we don't process the packet. This prevents an
 		// attack vector where the discovery protocol could be used to amplify traffic in a
 		// DDOS attack. A malicious actor would send a findnode request with the IP address
@@ -645,7 +667,7 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 		// findnode) to the victim.
 		return errUnknownNode
 	}
-	target := crypto.Keccak256Hash(req.Target[:])
+	target := enode.ID(crypto.Keccak256Hash(req.Target[:]))
 	t.mutex.Lock()
 	closest := t.closest(target, bucketSize).entries
 	t.mutex.Unlock()
@@ -655,7 +677,7 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 	// Send neighbors in chunks with at most maxNeighbors per packet
 	// to stay below the 1280 byte limit.
 	for _, n := range closest {
-		if netutil.CheckRelayIP(from.IP, n.IP) == nil {
+		if netutil.CheckRelayIP(from.IP, n.IP()) == nil {
 			p.Nodes = append(p.Nodes, nodeToRPC(n))
 		}
 		if len(p.Nodes) == maxNeighbors {
@@ -672,11 +694,11 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 
 func (req *findnode) name() string { return "FINDNODE/v4" }
 
-func (req *neighbors) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error {
+func (req *neighbors) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
 	if expired(req.Expiration) {
 		return errExpired
 	}
-	if !t.handleReply(fromID, neighborsPacket, req) {
+	if !t.handleReply(fromKey.id(), neighborsPacket, req) {
 		return errUnsolicitedReply
 	}
 	return nil