path: root/p2p/protocols/protocol_test.go

// Copyright 2017 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 protocols

import (
    "context"
    "errors"
    "fmt"
    "testing"
    "time"

    "github.com/ethereum/go-ethereum/p2p"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/p2p/simulations/adapters"
    p2ptest "github.com/ethereum/go-ethereum/p2p/testing"
)

// handshake message type
type hs0 struct {
    C uint
}

// message to kill/drop the peer with nodeID
type kill struct {
    C discover.NodeID
}

// message to drop connection
type drop struct {
}

/// protoHandshake represents module-independent aspects of the protocol and is
// the first message peers send and receive as part the initial exchange
type protoHandshake struct {
    Version   uint   // local and remote peer should have identical version
    NetworkID string // local and remote peer should have identical network id
}

// checkProtoHandshake verifies local and remote protoHandshakes match
func checkProtoHandshake(testVersion uint, testNetworkID string) func(interface{}) error {
    return func(rhs interface{}) error {
        remote := rhs.(*protoHandshake)
        if remote.NetworkID != testNetworkID {
            return fmt.Errorf("%s (!= %s)", remote.NetworkID, testNetworkID)
        }

        if remote.Version != testVersion {
            return fmt.Errorf("%d (!= %d)", remote.Version, testVersion)
        }
        return nil
    }
}

// newProtocol sets up a protocol
// the run function here demonstrates a typical protocol using peerPool, handshake
// and messages registered to handlers
func newProtocol(pp *p2ptest.TestPeerPool) func(*p2p.Peer, p2p.MsgReadWriter) error {
    spec := &Spec{
        Name:       "test",
        Version:    42,
        MaxMsgSize: 10 * 1024,
        Messages: []interface{}{
            protoHandshake{},
            hs0{},
            kill{},
            drop{},
        },
    }
    return func(p *p2p.Peer, rw p2p.MsgReadWriter) error {
        peer := NewPeer(p, rw, spec)

        // initiate one-off protohandshake and check validity
        ctx, cancel := context.WithTimeout(context.Background(), time.Second)
        defer cancel()
        phs := &protoHandshake{42, "420"}
        hsCheck := checkProtoHandshake(phs.Version, phs.NetworkID)
        _, err := peer.Handshake(ctx, phs, hsCheck)
        if err != nil {
            return err
        }

        lhs := &hs0{42}
        // module handshake demonstrating a simple repeatable exchange of same-type message
        hs, err := peer.Handshake(ctx, lhs, nil)
        if err != nil {
            return err
        }

        if rmhs := hs.(*hs0); rmhs.C > lhs.C {
            return fmt.Errorf("handshake mismatch remote %v > local %v", rmhs.C, lhs.C)
        }

        handle := func(msg interface{}) error {
            switch msg := msg.(type) {

            case *protoHandshake:
                return errors.New("duplicate handshake")

            case *hs0:
                rhs := msg
                if rhs.C > lhs.C {
                    return fmt.Errorf("handshake mismatch remote %v > local %v", rhs.C, lhs.C)
                }
                lhs.C += rhs.C
                return peer.Send(lhs)

            case *kill:
                // demonstrates use of peerPool, killing another peer connection as a response to a message
                id := msg.C
                pp.Get(id).Drop(errors.New("killed"))
                return nil

            case *drop:
                // for testing we can trigger self induced disconnect upon receiving drop message
                return errors.New("dropped")

            default:
                return fmt.Errorf("unknown message type: %T", msg)
            }
        }

        pp.Add(peer)
        defer pp.Remove(peer)
        return peer.Run(handle)
    }
}

func protocolTester(t *testing.T, pp *p2ptest.TestPeerPool) *p2ptest.ProtocolTester {
    conf := adapters.RandomNodeConfig()
    return p2ptest.NewProtocolTester(t, conf.ID, 2, newProtocol(pp))
}

func protoHandshakeExchange(id discover.NodeID, proto *protoHandshake) []p2ptest.Exchange {

    return []p2ptest.Exchange{
        {
            Expects: []p2ptest.Expect{
                {
                    Code: 0,
                    Msg:  &protoHandshake{42, "420"},
                    Peer: id,
                },
            },
        },
        {
            Triggers: []p2ptest.Trigger{
                {
                    Code: 0,
                    Msg:  proto,
                    Peer: id,
                },
            },
        },
    }
}

func runProtoHandshake(t *testing.T, proto *protoHandshake, errs ...error) {
    pp := p2ptest.NewTestPeerPool()
    s := protocolTester(t, pp)
    // TODO: make this more than one handshake
    id := s.IDs[0]
    if err := s.TestExchanges(protoHandshakeExchange(id, proto)...); err != nil {
        t.Fatal(err)
    }
    var disconnects []*p2ptest.Disconnect
    for i, err := range errs {
        disconnects = append(disconnects, &p2ptest.Disconnect{Peer: s.IDs[i], Error: err})
    }
    if err := s.TestDisconnected(disconnects...); err != nil {
        t.Fatal(err)
    }
}

func TestProtoHandshakeVersionMismatch(t *testing.T) {
    runProtoHandshake(t, &protoHandshake{41, "420"}, errorf(ErrHandshake, errorf(ErrHandler, "(msg code 0): 41 (!= 42)").Error()))
}

func TestProtoHandshakeNetworkIDMismatch(t *testing.T) {
    runProtoHandshake(t, &protoHandshake{42, "421"}, errorf(ErrHandshake, errorf(ErrHandler, "(msg code 0): 421 (!= 420)").Error()))
}

func TestProtoHandshakeSuccess(t *testing.T) {
    runProtoHandshake(t, &protoHandshake{42, "420"})
}

func moduleHandshakeExchange(id discover.NodeID, resp uint) []p2ptest.Exchange {

    return []p2ptest.Exchange{
        {
            Expects: []p2ptest.Expect{
                {
                    Code: 1,
                    Msg:  &hs0{42},
                    Peer: id,
                },
            },
        },
        {
            Triggers: []p2ptest.Trigger{
                {
                    Code: 1,
                    Msg:  &hs0{resp},
                    Peer: id,
                },
            },
        },
    }
}

func runModuleHandshake(t *testing.T, resp uint, errs ...error) {
    pp := p2ptest.NewTestPeerPool()
    s := protocolTester(t, pp)
    id := s.IDs[0]
    if err := s.TestExchanges(protoHandshakeExchange(id, &protoHandshake{42, "420"})...); err != nil {
        t.Fatal(err)
    }
    if err := s.TestExchanges(moduleHandshakeExchange(id, resp)...); err != nil {
        t.Fatal(err)
    }
    var disconnects []*p2ptest.Disconnect
    for i, err := range errs {
        disconnects = append(disconnects, &p2ptest.Disconnect{Peer: s.IDs[i], Error: err})
    }
    if err := s.TestDisconnected(disconnects...); err != nil {
        t.Fatal(err)
    }
}

func TestModuleHandshakeError(t *testing.T) {
    runModuleHandshake(t, 43, fmt.Errorf("handshake mismatch remote 43 > local 42"))
}

func TestModuleHandshakeSuccess(t *testing.T) {
    runModuleHandshake(t, 42)
}

// testing complex interactions over multiple peers, relaying, dropping
func testMultiPeerSetup(a, b discover.NodeID) []p2ptest.Exchange {

    return []p2ptest.Exchange{
        {
            Label: "primary handshake",
            Expects: []p2ptest.Expect{
                {
                    Code: 0,
                    Msg:  &protoHandshake{42, "420"},
                    Peer: a,
                },
                {
                    Code: 0,
                    Msg:  &protoHandshake{42, "420"},
                    Peer: b,
                },
            },
        },
        {
            Label: "module handshake",
            Triggers: []p2ptest.Trigger{
                {
                    Code: 0,
                    Msg:  &protoHandshake{42, "420"},
                    Peer: a,
                },
                {
                    Code: 0,
                    Msg:  &protoHandshake{42, "420"},
                    Peer: b,
                },
            },
            Expects: []p2ptest.Expect{
                {
                    Code: 1,
                    Msg:  &hs0{42},
                    Peer: a,
                },
                {
                    Code: 1,
                    Msg:  &hs0{42},
                    Peer: b,
                },
            },
        },

        {Label: "alternative module handshake", Triggers: []p2ptest.Trigger{{Code: 1, Msg: &hs0{41}, Peer: a},
            {Code: 1, Msg: &hs0{41}, Peer: b}}},
        {Label: "repeated module handshake", Triggers: []p2ptest.Trigger{{Code: 1, Msg: &hs0{1}, Peer: a}}},
        {Label: "receiving repeated module handshake", Expects: []p2ptest.Expect{{Code: 1, Msg: &hs0{43}, Peer: a}}}}
}

func runMultiplePeers(t *testing.T, peer int, errs ...error) {
    pp := p2ptest.NewTestPeerPool()
    s := protocolTester(t, pp)

    if err := s.TestExchanges(testMultiPeerSetup(s.IDs[0], s.IDs[1])...); err != nil {
        t.Fatal(err)
    }
    // after some exchanges of messages, we can test state changes
    // here this is simply demonstrated by the peerPool
    // after the handshake negotiations peers must be added to the pool
    // time.Sleep(1)
    tick := time.NewTicker(10 * time.Millisecond)
    timeout := time.NewTimer(1 * time.Second)
WAIT:
    for {
        select {
        case <-tick.C:
            if pp.Has(s.IDs[0]) {
                break WAIT
            }
        case <-timeout.C:
            t.Fatal("timeout")
        }
    }
    if !pp.Has(s.IDs[1]) {
        t.Fatalf("missing peer test-1: %v (%v)", pp, s.IDs)
    }

    // peer 0 sends kill request for peer with index <peer>
    err := s.TestExchanges(p2ptest.Exchange{
        Triggers: []p2ptest.Trigger{
            {
                Code: 2,
                Msg:  &kill{s.IDs[peer]},
                Peer: s.IDs[0],
            },
        },
    })

    if err != nil {
        t.Fatal(err)
    }

    // the peer not killed sends a drop request
    err = s.TestExchanges(p2ptest.Exchange{
        Triggers: []p2ptest.Trigger{
            {
                Code: 3,
                Msg:  &drop{},
                Peer: s.IDs[(peer+1)%2],
            },
        },
    })

    if err != nil {
        t.Fatal(err)
    }

    // check the actual discconnect errors on the individual peers
    var disconnects []*p2ptest.Disconnect
    for i, err := range errs {
        disconnects = append(disconnects, &p2ptest.Disconnect{Peer: s.IDs[i], Error: err})
    }
    if err := s.TestDisconnected(disconnects...); err != nil {
        t.Fatal(err)
    }
    // test if disconnected peers have been removed from peerPool
    if pp.Has(s.IDs[peer]) {
        t.Fatalf("peer test-%v not dropped: %v (%v)", peer, pp, s.IDs)
    }

}

func TestMultiplePeersDropSelf(t *testing.T) {
    runMultiplePeers(t, 0,
        fmt.Errorf("subprotocol error"),
        fmt.Errorf("Message handler error: (msg code 3): dropped"),
    )
}

func TestMultiplePeersDropOther(t *testing.T) {
    runMultiplePeers(t, 1,
        fmt.Errorf("Message handler error: (msg code 3): dropped"),
        fmt.Errorf("subprotocol error"),
    )
}