supress useless peers in discovery

p2p/discover/discfilter/discfilter.go

@@ -0,0 +1,44 @@
+package discfilter
+
+import (
+	lru "github.com/hashicorp/golang-lru"
+
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/enr"
+)
+
+var (
+	enabled    = false
+	dynamic, _ = lru.New(50000)
+)
+
+func Enable() {
+	enabled = true
+}
+
+func Ban(id enode.ID) {
+	if enabled {
+		dynamic.Add(id, struct{}{})
+	}
+}
+
+func BannedDynamic(id enode.ID) bool {
+	if !enabled {
+		return false
+	}
+	return dynamic.Contains(id)
+}
+
+func BannedStatic(rec *enr.Record) bool {
+	if !enabled {
+		return false
+	}
+	return rec.Has("eth") || rec.Has("eth2")
+}
+
+func Banned(id enode.ID, rec *enr.Record) bool {
+	if !enabled {
+		return false
+	}
+	return BannedStatic(rec) || BannedDynamic(id)
+}

p2p/discover/v4_udp.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/discover/discfilter"
 	"github.com/ethereum/go-ethereum/p2p/discover/v4wire"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
@@ -739,6 +740,10 @@ func (t *UDPv4) handleFindnode(h *packetHandlerV4, from *net.UDPAddr, fromID eno
 		if len(t.privateNodes) > 0 && containsEnode(t.privateNodes, &n.Node) {
 			continue
 		}
+		// Don't advertise the bots
+		if discfilter.Banned(n.ID(), n.Record()) {
+			continue
+		}
 		if netutil.CheckRelayIP(from.IP, n.IP()) == nil {
 			p.Nodes = append(p.Nodes, nodeToRPC(n))
 		}

p2p/discover/v5_udp.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common/mclock"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/discover/discfilter"
 	"github.com/ethereum/go-ethereum/p2p/discover/v5wire"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
@@ -824,6 +825,10 @@ func (t *UDPv5) collectTableNodes(rip net.IP, distances []uint, limit int) []*en
 			if len(t.privateNodes) > 0 && containsEnode(t.privateNodes, n) {
 				continue
 			}
+			// Don't advertise the bots
+			if discfilter.Banned(n.ID(), n.Record()) {
+				continue
+			}
 			// TODO livenessChecks > 1
 			if netutil.CheckRelayIP(rip, n.IP()) != nil {
 				continue

p2p/enode/idscheme.go

@@ -19,14 +19,14 @@ package enode
 import (
 	"crypto/ecdsa"
 	"fmt"
-	"github.com/ethereum/go-ethereum/core/forkid"
 	"io"
 
+	"golang.org/x/crypto/sha3"
+
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/p2p/enr"
 	"github.com/ethereum/go-ethereum/rlp"
-	"golang.org/x/crypto/sha3"
 )
 
 // List of known secure identity schemes.
@@ -63,12 +63,6 @@ func SignV4(r *enr.Record, privkey *ecdsa.PrivateKey) error {
 }
 
 func (V4ID) Verify(r *enr.Record, sig []byte) error {
-	var opera operaNodeEnrEntry
-	err := r.Load(&opera)
-	if err != nil {
-		return fmt.Errorf("invalid opera node; %s", err.Error())
-	}
-
 	var entry s256raw
 	if err := r.Load(&entry); err != nil {
 		return err
@@ -165,16 +159,3 @@ func SignNull(r *enr.Record, id ID) *Node {
 	}
 	return &Node{r: *r, id: id}
 }
-
-// operaNodeEnrEntry is the ENR entry which advertises `eth` protocol on the discovery.
-type operaNodeEnrEntry struct {
-	ForkID forkid.ID // Fork identifier per EIP-2124
-
-	// Ignore additional fields (for forward compatibility).
-	Rest []rlp.RawValue `rlp:"tail"`
-}
-
-// ENRKey implements enr.Entry.
-func (e operaNodeEnrEntry) ENRKey() string {
-	return "opera"
-}

p2p/enr/enr.go

@@ -126,6 +126,19 @@ func (r *Record) Load(e Entry) error {
 	return &KeyError{Key: e.ENRKey(), Err: errNotFound}
 }
 
+func (r *Record) Has(key string) bool {
+	i := sort.Search(len(r.pairs), func(i int) bool { return r.pairs[i].k >= key })
+	return i < len(r.pairs) && r.pairs[i].k == key
+}
+
+func (r *Record) String() string {
+	str := ""
+	for _, p := range r.pairs {
+		str += p.k + " "
+	}
+	return str
+}
+
 // Set adds or updates the given entry in the record. It panics if the value can't be
 // encoded. If the record is signed, Set increments the sequence number and invalidates
 // the sequence number.

p2p/server.go

@@ -23,6 +23,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"math/rand"
 	"net"
 	"sort"
 	"sync"
@@ -35,6 +36,7 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/discover"
+	"github.com/ethereum/go-ethereum/p2p/discover/discfilter"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
 	"github.com/ethereum/go-ethereum/p2p/nat"
@@ -843,6 +845,10 @@ func (srv *Server) postHandshakeChecks(peers map[enode.ID]*Peer, inboundCount in
 	case c.node.ID() == srv.localnode.ID():
 		return DiscSelf
 	default:
+		if !c.is(trustedConn) && discfilter.Banned(c.node.ID(), c.node.Record()) && rand.Intn(5) != 0 {
+			// rarely accept useless peers
+			return DiscTooManyPeers
+		}
 		return nil
 	}
 }