p2p, p2p/discover: add dial metrics (#27621)

This PR adds metrics for p2p dialing, which gives us visibility into the quality of the dial 
candidates  returned by our discovery methods.

eth/protocols/eth/handshake.go

@@ -17,12 +17,14 @@
 package eth
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/forkid"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/p2p"
 )
 
@@ -59,9 +61,11 @@ func (p *Peer) Handshake(network uint64, td *big.Int, head common.Hash, genesis
 		select {
 		case err := <-errc:
 			if err != nil {
+				markError(p, err)
 				return err
 			}
 		case <-timeout.C:
+			markError(p, p2p.DiscReadTimeout)
 			return p2p.DiscReadTimeout
 		}
 	}
@@ -105,3 +109,25 @@ func (p *Peer) readStatus(network uint64, status *StatusPacket, genesis common.H
 	}
 	return nil
 }
+
+// markError registers the error with the corresponding metric.
+func markError(p *Peer, err error) {
+	if !metrics.Enabled {
+		return
+	}
+	m := meters.get(p.Inbound())
+	switch errors.Unwrap(err) {
+	case errNetworkIDMismatch:
+		m.networkIDMismatch.Mark(1)
+	case errProtocolVersionMismatch:
+		m.protocolVersionMismatch.Mark(1)
+	case errGenesisMismatch:
+		m.genesisMismatch.Mark(1)
+	case errForkIDRejected:
+		m.forkidRejected.Mark(1)
+	case p2p.DiscReadTimeout:
+		m.timeoutError.Mark(1)
+	default:
+		m.peerError.Mark(1)
+	}
+}

eth/protocols/eth/metrics.go

@@ -0,0 +1,81 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package eth
+
+import "github.com/ethereum/go-ethereum/metrics"
+
+// meters stores ingress and egress handshake meters.
+var meters bidirectionalMeters
+
+// bidirectionalMeters stores ingress and egress handshake meters.
+type bidirectionalMeters struct {
+	ingress *hsMeters
+	egress  *hsMeters
+}
+
+// get returns the corresponding meter depending if ingress or egress is
+// desired.
+func (h *bidirectionalMeters) get(ingress bool) *hsMeters {
+	if ingress {
+		return h.ingress
+	}
+	return h.egress
+}
+
+// hsMeters is a collection of meters which track metrics related to the
+// eth subprotocol handshake.
+type hsMeters struct {
+	// peerError measures the number of errors related to incorrect peer
+	// behaviour, such as invalid message code, size, encoding, etc.
+	peerError metrics.Meter
+
+	// timeoutError measures the number of timeouts.
+	timeoutError metrics.Meter
+
+	// networkIDMismatch measures the number of network id mismatch errors.
+	networkIDMismatch metrics.Meter
+
+	// protocolVersionMismatch measures the number of differing protocol
+	// versions.
+	protocolVersionMismatch metrics.Meter
+
+	// genesisMismatch measures the number of differing genesises.
+	genesisMismatch metrics.Meter
+
+	// forkidRejected measures the number of differing forkids.
+	forkidRejected metrics.Meter
+}
+
+// newHandshakeMeters registers and returns handshake meters for the given
+// base.
+func newHandshakeMeters(base string) *hsMeters {
+	return &hsMeters{
+		peerError:               metrics.NewRegisteredMeter(base+"error/peer", nil),
+		timeoutError:            metrics.NewRegisteredMeter(base+"error/timeout", nil),
+		networkIDMismatch:       metrics.NewRegisteredMeter(base+"error/network", nil),
+		protocolVersionMismatch: metrics.NewRegisteredMeter(base+"error/version", nil),
+		genesisMismatch:         metrics.NewRegisteredMeter(base+"error/genesis", nil),
+		forkidRejected:          metrics.NewRegisteredMeter(base+"error/forkid", nil),
+	}
+}
+
+func init() {
+	meters = bidirectionalMeters{
+		ingress: newHandshakeMeters("eth/protocols/eth/ingress/handshake/"),
+		egress:  newHandshakeMeters("eth/protocols/eth/egress/handshake/"),
+	}
+}

eth/protocols/snap/metrics.go

@@ -0,0 +1,29 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package snap
+
+import (
+	metrics "github.com/ethereum/go-ethereum/metrics"
+)
+
+var (
+	ingressRegistrationErrorName = "eth/protocols/snap/ingress/registration/error"
+	egressRegistrationErrorName  = "eth/protocols/snap/egress/registration/error"
+
+	IngressRegistrationErrorMeter = metrics.NewRegisteredMeter(ingressRegistrationErrorName, nil)
+	EgressRegistrationErrorMeter  = metrics.NewRegisteredMeter(egressRegistrationErrorName, nil)
+)