path: root/consensus/clique/snapshot_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 clique

import (
    "bytes"
    "crypto/ecdsa"
    "math/big"
    "testing"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/rawdb"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/params"
)

type testerVote struct {
    signer string
    voted  string
    auth   bool
}

// testerAccountPool is a pool to maintain currently active tester accounts,
// mapped from textual names used in the tests below to actual Ethereum private
// keys capable of signing transactions.
type testerAccountPool struct {
    accounts map[string]*ecdsa.PrivateKey
}

func newTesterAccountPool() *testerAccountPool {
    return &testerAccountPool{
        accounts: make(map[string]*ecdsa.PrivateKey),
    }
}

func (ap *testerAccountPool) sign(header *types.Header, signer string) {
    // Ensure we have a persistent key for the signer
    if ap.accounts[signer] == nil {
        ap.accounts[signer], _ = crypto.GenerateKey()
    }
    // Sign the header and embed the signature in extra data
    sig, _ := crypto.Sign(sigHash(header).Bytes(), ap.accounts[signer])
    copy(header.Extra[len(header.Extra)-65:], sig)
}

func (ap *testerAccountPool) address(account string) common.Address {
    // Ensure we have a persistent key for the account
    if ap.accounts[account] == nil {
        ap.accounts[account], _ = crypto.GenerateKey()
    }
    // Resolve and return the Ethereum address
    return crypto.PubkeyToAddress(ap.accounts[account].PublicKey)
}

// testerChainReader implements consensus.ChainReader to access the genesis
// block. All other methods and requests will panic.
type testerChainReader struct {
    db ethdb.Database
}

func (r *testerChainReader) Config() *params.ChainConfig                 { return params.AllCliqueProtocolChanges }
func (r *testerChainReader) CurrentHeader() *types.Header                { panic("not supported") }
func (r *testerChainReader) GetHeader(common.Hash, uint64) *types.Header { panic("not supported") }
func (r *testerChainReader) GetBlock(common.Hash, uint64) *types.Block   { panic("not supported") }
func (r *testerChainReader) GetHeaderByHash(common.Hash) *types.Header   { panic("not supported") }
func (r *testerChainReader) GetHeaderByNumber(number uint64) *types.Header {
    if number == 0 {
        return rawdb.ReadHeader(r.db, rawdb.ReadCanonicalHash(r.db, 0), 0)
    }
    panic("not supported")
}

// Tests that voting is evaluated correctly for various simple and complex scenarios.
func TestVoting(t *testing.T) {
    // Define the various voting scenarios to test
    tests := []struct {
        epoch   uint64
        signers []string
        votes   []testerVote
        results []string
    }{
        {
            // Single signer, no votes cast
            signers: []string{"A"},
            votes:   []testerVote{{signer: "A"}},
            results: []string{"A"},
        }, {
            // Single signer, voting to add two others (only accept first, second needs 2 votes)
            signers: []string{"A"},
            votes: []testerVote{
                {signer: "A", voted: "B", auth: true},
                {signer: "B"},
                {signer: "A", voted: "C", auth: true},
            },
            results: []string{"A", "B"},
        }, {
            // Two signers, voting to add three others (only accept first two, third needs 3 votes already)
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: true},
                {signer: "B", voted: "C", auth: true},
                {signer: "A", voted: "D", auth: true},
                {signer: "B", voted: "D", auth: true},
                {signer: "C"},
                {signer: "A", voted: "E", auth: true},
                {signer: "B", voted: "E", auth: true},
            },
            results: []string{"A", "B", "C", "D"},
        }, {
            // Single signer, dropping itself (weird, but one less cornercase by explicitly allowing this)
            signers: []string{"A"},
            votes: []testerVote{
                {signer: "A", voted: "A", auth: false},
            },
            results: []string{},
        }, {
            // Two signers, actually needing mutual consent to drop either of them (not fulfilled)
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "B", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Two signers, actually needing mutual consent to drop either of them (fulfilled)
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "B", auth: false},
                {signer: "B", voted: "B", auth: false},
            },
            results: []string{"A"},
        }, {
            // Three signers, two of them deciding to drop the third
            signers: []string{"A", "B", "C"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B", voted: "C", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Four signers, consensus of two not being enough to drop anyone
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B", voted: "C", auth: false},
            },
            results: []string{"A", "B", "C", "D"},
        }, {
            // Four signers, consensus of three already being enough to drop someone
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "D", auth: false},
                {signer: "B", voted: "D", auth: false},
                {signer: "C", voted: "D", auth: false},
            },
            results: []string{"A", "B", "C"},
        }, {
            // Authorizations are counted once per signer per target
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: true},
                {signer: "B"},
                {signer: "A", voted: "C", auth: true},
                {signer: "B"},
                {signer: "A", voted: "C", auth: true},
            },
            results: []string{"A", "B"},
        }, {
            // Authorizing multiple accounts concurrently is permitted
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: true},
                {signer: "B"},
                {signer: "A", voted: "D", auth: true},
                {signer: "B"},
                {signer: "A"},
                {signer: "B", voted: "D", auth: true},
                {signer: "A"},
                {signer: "B", voted: "C", auth: true},
            },
            results: []string{"A", "B", "C", "D"},
        }, {
            // Deauthorizations are counted once per signer per target
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "B", auth: false},
                {signer: "B"},
                {signer: "A", voted: "B", auth: false},
                {signer: "B"},
                {signer: "A", voted: "B", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Deauthorizing multiple accounts concurrently is permitted
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B"},
                {signer: "C"},
                {signer: "A", voted: "D", auth: false},
                {signer: "B"},
                {signer: "C"},
                {signer: "A"},
                {signer: "B", voted: "D", auth: false},
                {signer: "C", voted: "D", auth: false},
                {signer: "A"},
                {signer: "B", voted: "C", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Votes from deauthorized signers are discarded immediately (deauth votes)
            signers: []string{"A", "B", "C"},
            votes: []testerVote{
                {signer: "C", voted: "B", auth: false},
                {signer: "A", voted: "C", auth: false},
                {signer: "B", voted: "C", auth: false},
                {signer: "A", voted: "B", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Votes from deauthorized signers are discarded immediately (auth votes)
            signers: []string{"A", "B", "C"},
            votes: []testerVote{
                {signer: "C", voted: "B", auth: false},
                {signer: "A", voted: "C", auth: false},
                {signer: "B", voted: "C", auth: false},
                {signer: "A", voted: "B", auth: false},
            },
            results: []string{"A", "B"},
        }, {
            // Cascading changes are not allowed, only the account being voted on may change
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B"},
                {signer: "C"},
                {signer: "A", voted: "D", auth: false},
                {signer: "B", voted: "C", auth: false},
                {signer: "C"},
                {signer: "A"},
                {signer: "B", voted: "D", auth: false},
                {signer: "C", voted: "D", auth: false},
            },
            results: []string{"A", "B", "C"},
        }, {
            // Changes reaching consensus out of bounds (via a deauth) execute on touch
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B"},
                {signer: "C"},
                {signer: "A", voted: "D", auth: false},
                {signer: "B", voted: "C", auth: false},
                {signer: "C"},
                {signer: "A"},
                {signer: "B", voted: "D", auth: false},
                {signer: "C", voted: "D", auth: false},
                {signer: "A"},
                {signer: "C", voted: "C", auth: true},
            },
            results: []string{"A", "B"},
        }, {
            // Changes reaching consensus out of bounds (via a deauth) may go out of consensus on first touch
            signers: []string{"A", "B", "C", "D"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: false},
                {signer: "B"},
                {signer: "C"},
                {signer: "A", voted: "D", auth: false},
                {signer: "B", voted: "C", auth: false},
                {signer: "C"},
                {signer: "A"},
                {signer: "B", voted: "D", auth: false},
                {signer: "C", voted: "D", auth: false},
                {signer: "A"},
                {signer: "B", voted: "C", auth: true},
            },
            results: []string{"A", "B", "C"},
        }, {
            // Ensure that pending votes don't survive authorization status changes. This
            // corner case can only appear if a signer is quickly added, removed and then
            // readded (or the inverse), while one of the original voters dropped. If a
            // past vote is left cached in the system somewhere, this will interfere with
            // the final signer outcome.
            signers: []string{"A", "B", "C", "D", "E"},
            votes: []testerVote{
                {signer: "A", voted: "F", auth: true}, // Authorize F, 3 votes needed
                {signer: "B", voted: "F", auth: true},
                {signer: "C", voted: "F", auth: true},
                {signer: "D", voted: "F", auth: false}, // Deauthorize F, 4 votes needed (leave A's previous vote "unchanged")
                {signer: "E", voted: "F", auth: false},
                {signer: "B", voted: "F", auth: false},
                {signer: "C", voted: "F", auth: false},
                {signer: "D", voted: "F", auth: true}, // Almost authorize F, 2/3 votes needed
                {signer: "E", voted: "F", auth: true},
                {signer: "B", voted: "A", auth: false}, // Deauthorize A, 3 votes needed
                {signer: "C", voted: "A", auth: false},
                {signer: "D", voted: "A", auth: false},
                {signer: "B", voted: "F", auth: true}, // Finish authorizing F, 3/3 votes needed
            },
            results: []string{"B", "C", "D", "E", "F"},
        }, {
            // Epoch transitions reset all votes to allow chain checkpointing
            epoch:   3,
            signers: []string{"A", "B"},
            votes: []testerVote{
                {signer: "A", voted: "C", auth: true},
                {signer: "B"},
                {signer: "A"}, // Checkpoint block, (don't vote here, it's validated outside of snapshots)
                {signer: "B", voted: "C", auth: true},
            },
            results: []string{"A", "B"},
        },
    }
    // Run through the scenarios and test them
    for i, tt := range tests {
        // Create the account pool and generate the initial set of signers
        accounts := newTesterAccountPool()

        signers := make([]common.Address, len(tt.signers))
        for j, signer := range tt.signers {
            signers[j] = accounts.address(signer)
        }
        for j := 0; j < len(signers); j++ {
            for k := j + 1; k < len(signers); k++ {
                if bytes.Compare(signers[j][:], signers[k][:]) > 0 {
                    signers[j], signers[k] = signers[k], signers[j]
                }
            }
        }
        // Create the genesis block with the initial set of signers
        genesis := &core.Genesis{
            ExtraData: make([]byte, extraVanity+common.AddressLength*len(signers)+extraSeal),
        }
        for j, signer := range signers {
            copy(genesis.ExtraData[extraVanity+j*common.AddressLength:], signer[:])
        }
        // Create a pristine blockchain with the genesis injected
        db, _ := ethdb.NewMemDatabase()
        genesis.Commit(db)

        // Assemble a chain of headers from the cast votes
        headers := make([]*types.Header, len(tt.votes))
        for j, vote := range tt.votes {
            headers[j] = &types.Header{
                Number:   big.NewInt(int64(j) + 1),
                Time:     big.NewInt(int64(j) * int64(blockPeriod)),
                Coinbase: accounts.address(vote.voted),
                Extra:    make([]byte, extraVanity+extraSeal),
            }
            if j > 0 {
                headers[j].ParentHash = headers[j-1].Hash()
            }
            if vote.auth {
                copy(headers[j].Nonce[:], nonceAuthVote)
            }
            accounts.sign(headers[j], vote.signer)
        }
        // Pass all the headers through clique and ensure tallying succeeds
        head := headers[len(headers)-1]

        snap, err := New(&params.CliqueConfig{Epoch: tt.epoch}, db).snapshot(&testerChainReader{db: db}, head.Number.Uint64(), head.Hash(), headers)
        if err != nil {
            t.Errorf("test %d: failed to create voting snapshot: %v", i, err)
            continue
        }
        // Verify the final list of signers against the expected ones
        signers = make([]common.Address, len(tt.results))
        for j, signer := range tt.results {
            signers[j] = accounts.address(signer)
        }
        for j := 0; j < len(signers); j++ {
            for k := j + 1; k < len(signers); k++ {
                if bytes.Compare(signers[j][:], signers[k][:]) > 0 {
                    signers[j], signers[k] = signers[k], signers[j]
                }
            }
        }
        result := snap.signers()
        if len(result) != len(signers) {
            t.Errorf("test %d: signers mismatch: have %x, want %x", i, result, signers)
            continue
        }
        for j := 0; j < len(result); j++ {
            if !bytes.Equal(result[j][:], signers[j][:]) {
                t.Errorf("test %d, signer %d: signer mismatch: have %x, want %x", i, j, result[j], signers[j])
            }
        }
    }
}