diff options
| -rw-r--r-- | pow/ethash.go | 8 | ||||
| -rw-r--r-- | pow/ethash_algo.go | 37 | ||||
| -rw-r--r-- | pow/ethash_algo_go1.7.go | 47 | ||||
| -rw-r--r-- | pow/ethash_algo_go1.8.go | 57 | ||||
| -rw-r--r-- | pow/ethash_algo_go1.8_test.go | 46 | ||||
| -rw-r--r-- | pow/ethash_algo_test.go | 25 |
6 files changed, 157 insertions, 63 deletions
diff --git a/pow/ethash.go b/pow/ethash.go index 602f9324f..9dfeedb78 100644 --- a/pow/ethash.go +++ b/pow/ethash.go @@ -35,6 +35,7 @@ import ( ) var ( + ErrNonceOutOfRange = errors.New("nonce out of range") ErrInvalidDifficulty = errors.New("non-positive difficulty") ErrInvalidMixDigest = errors.New("invalid mix digest") ErrInvalidPoW = errors.New("pow difficulty invalid") @@ -174,13 +175,18 @@ func NewSharedEthash() PoW { // Verify implements PoW, checking whether the given block satisfies the PoW // difficulty requirements. func (ethash *Ethash) Verify(block Block) error { + // Sanity check that the block number is below the lookup table size (60M blocks) + number := block.NumberU64() + if number/epochLength >= uint64(len(cacheSizes)) { + // Go < 1.7 cannot calculate new cache/dataset sizes (no fast prime check) + return ErrNonceOutOfRange + } // Ensure twe have a valid difficulty for the block difficulty := block.Difficulty() if difficulty.Sign() <= 0 { return ErrInvalidDifficulty } // Recompute the digest and PoW value and verify against the block - number := block.NumberU64() cache := ethash.cache(number) size := datasetSize(number) diff --git a/pow/ethash_algo.go b/pow/ethash_algo.go index f6d05880a..d3fac8d5b 100644 --- a/pow/ethash_algo.go +++ b/pow/ethash_algo.go @@ -19,7 +19,6 @@ package pow import ( "encoding/binary" "io" - "math/big" "runtime" "sync" "sync/atomic" @@ -45,42 +44,6 @@ const ( loopAccesses = 64 // Number of accesses in hashimoto loop ) -// cacheSize calculates and returns the size of the ethash verification cache that -// belongs to a certain block number. The cache size grows linearly, however, we -// always take the highest prime below the linearly growing threshold in order to -// reduce the risk of accidental regularities leading to cyclic behavior. -func cacheSize(block uint64) uint64 { - // If we have a pre-generated value, use that - epoch := int(block / epochLength) - if epoch < len(cacheSizes) { - return cacheSizes[epoch] - } - // No known cache size, calculate manually (sanity branch only) - size := uint64(cacheInitBytes + cacheGrowthBytes*epoch - hashBytes) - for !new(big.Int).SetUint64(size / hashBytes).ProbablyPrime(1) { // Always accurate for n < 2^64 - size -= 2 * hashBytes - } - return size -} - -// datasetSize calculates and returns the size of the ethash mining dataset that -// belongs to a certain block number. The dataset size grows linearly, however, we -// always take the highest prime below the linearly growing threshold in order to -// reduce the risk of accidental regularities leading to cyclic behavior. -func datasetSize(block uint64) uint64 { - // If we have a pre-generated value, use that - epoch := int(block / epochLength) - if epoch < len(datasetSizes) { - return datasetSizes[epoch] - } - // No known dataset size, calculate manually (sanity branch only) - size := uint64(datasetInitBytes + datasetGrowthBytes*epoch - mixBytes) - for !new(big.Int).SetUint64(size / mixBytes).ProbablyPrime(1) { // Always accurate for n < 2^64 - size -= 2 * mixBytes - } - return size -} - // seedHash is the seed to use for generating a verification cache and the mining // dataset. func seedHash(block uint64) []byte { diff --git a/pow/ethash_algo_go1.7.go b/pow/ethash_algo_go1.7.go new file mode 100644 index 000000000..ce05b3bb0 --- /dev/null +++ b/pow/ethash_algo_go1.7.go @@ -0,0 +1,47 @@ +// 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/>. + +// +build !go1.8 + +package pow + +// cacheSize calculates and returns the size of the ethash verification cache that +// belongs to a certain block number. The cache size grows linearly, however, we +// always take the highest prime below the linearly growing threshold in order to +// reduce the risk of accidental regularities leading to cyclic behavior. +func cacheSize(block uint64) uint64 { + // If we have a pre-generated value, use that + epoch := int(block / epochLength) + if epoch < len(cacheSizes) { + return cacheSizes[epoch] + } + // We don't have a way to verify primes fast before Go 1.8 + panic("fast prime testing unsupported in Go < 1.8") +} + +// datasetSize calculates and returns the size of the ethash mining dataset that +// belongs to a certain block number. The dataset size grows linearly, however, we +// always take the highest prime below the linearly growing threshold in order to +// reduce the risk of accidental regularities leading to cyclic behavior. +func datasetSize(block uint64) uint64 { + // If we have a pre-generated value, use that + epoch := int(block / epochLength) + if epoch < len(datasetSizes) { + return datasetSizes[epoch] + } + // We don't have a way to verify primes fast before Go 1.8 + panic("fast prime testing unsupported in Go < 1.8") +} diff --git a/pow/ethash_algo_go1.8.go b/pow/ethash_algo_go1.8.go new file mode 100644 index 000000000..cac96cd5e --- /dev/null +++ b/pow/ethash_algo_go1.8.go @@ -0,0 +1,57 @@ +// 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/>. + +// +build go1.8 + +package pow + +import "math/big" + +// cacheSize calculates and returns the size of the ethash verification cache that +// belongs to a certain block number. The cache size grows linearly, however, we +// always take the highest prime below the linearly growing threshold in order to +// reduce the risk of accidental regularities leading to cyclic behavior. +func cacheSize(block uint64) uint64 { + // If we have a pre-generated value, use that + epoch := int(block / epochLength) + if epoch < len(cacheSizes) { + return cacheSizes[epoch] + } + // No known cache size, calculate manually (sanity branch only) + size := uint64(cacheInitBytes + cacheGrowthBytes*uint64(epoch) - hashBytes) + for !new(big.Int).SetUint64(size / hashBytes).ProbablyPrime(1) { // Always accurate for n < 2^64 + size -= 2 * hashBytes + } + return size +} + +// datasetSize calculates and returns the size of the ethash mining dataset that +// belongs to a certain block number. The dataset size grows linearly, however, we +// always take the highest prime below the linearly growing threshold in order to +// reduce the risk of accidental regularities leading to cyclic behavior. +func datasetSize(block uint64) uint64 { + // If we have a pre-generated value, use that + epoch := int(block / epochLength) + if epoch < len(datasetSizes) { + return datasetSizes[epoch] + } + // No known dataset size, calculate manually (sanity branch only) + size := uint64(datasetInitBytes + datasetGrowthBytes*uint64(epoch) - mixBytes) + for !new(big.Int).SetUint64(size / mixBytes).ProbablyPrime(1) { // Always accurate for n < 2^64 + size -= 2 * mixBytes + } + return size +} diff --git a/pow/ethash_algo_go1.8_test.go b/pow/ethash_algo_go1.8_test.go new file mode 100644 index 000000000..57e0b0b7a --- /dev/null +++ b/pow/ethash_algo_go1.8_test.go @@ -0,0 +1,46 @@ +// 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/>. + +// +build go1.8 + +package pow + +import "testing" + +// Tests whether the dataset size calculator work correctly by cross checking the +// hard coded lookup table with the value generated by it. +func TestSizeCalculations(t *testing.T) { + var tests []uint64 + + // Verify all the cache sizes from the lookup table + defer func(sizes []uint64) { cacheSizes = sizes }(cacheSizes) + tests, cacheSizes = cacheSizes, []uint64{} + + for i, test := range tests { + if size := cacheSize(uint64(i*epochLength) + 1); size != test { + t.Errorf("cache %d: cache size mismatch: have %d, want %d", i, size, test) + } + } + // Verify all the dataset sizes from the lookup table + defer func(sizes []uint64) { datasetSizes = sizes }(datasetSizes) + tests, datasetSizes = datasetSizes, []uint64{} + + for i, test := range tests { + if size := datasetSize(uint64(i*epochLength) + 1); size != test { + t.Errorf("dataset %d: dataset size mismatch: have %d, want %d", i, size, test) + } + } +} diff --git a/pow/ethash_algo_test.go b/pow/ethash_algo_test.go index 253ddfa72..32e115db9 100644 --- a/pow/ethash_algo_test.go +++ b/pow/ethash_algo_test.go @@ -23,31 +23,6 @@ import ( "github.com/ethereum/go-ethereum/common/hexutil" ) -// Tests whether the dataset size calculator work correctly by cross checking the -// hard coded lookup table with the value generated by it. -func TestSizeCalculations(t *testing.T) { - var tests []uint64 - - // Verify all the cache sizes from the lookup table - defer func(sizes []uint64) { cacheSizes = sizes }(cacheSizes) - tests, cacheSizes = cacheSizes, []uint64{} - - for i, test := range tests { - if size := cacheSize(uint64(i*epochLength) + 1); size != test { - t.Errorf("cache %d: cache size mismatch: have %d, want %d", i, size, test) - } - } - // Verify all the dataset sizes from the lookup table - defer func(sizes []uint64) { datasetSizes = sizes }(datasetSizes) - tests, datasetSizes = datasetSizes, []uint64{} - - for i, test := range tests { - if size := datasetSize(uint64(i*epochLength) + 1); size != test { - t.Errorf("dataset %d: dataset size mismatch: have %d, want %d", i, size, test) - } - } -} - // Tests that verification caches can be correctly generated. func TestCacheGeneration(t *testing.T) { tests := []struct { |