// Copyright (C) 2014 The Syncthing Authors. // // This Source Code Form is subject to the terms of the Mozilla Public // License, v. 2.0. If a copy of the MPL was not distributed with this file, // You can obtain one at https://mozilla.org/MPL/2.0/. package scanner import ( "bytes" "context" "crypto/rand" "fmt" origAdler32 "hash/adler32" mrand "math/rand" "testing" "testing/quick" rollingAdler32 "github.com/chmduquesne/rollinghash/adler32" "github.com/syncthing/syncthing/lib/protocol" "github.com/syncthing/syncthing/lib/sha256" ) var blocksTestData = []struct { data []byte blocksize int hash []string weakhash []uint32 }{ {[]byte(""), 1024, []string{ "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"}, []uint32{0}, }, {[]byte("contents"), 1024, []string{ "d1b2a59fbea7e20077af9f91b27e95e865061b270be03ff539ab3b73587882e8"}, []uint32{0x0f3a036f}, }, {[]byte("contents"), 9, []string{ "d1b2a59fbea7e20077af9f91b27e95e865061b270be03ff539ab3b73587882e8"}, []uint32{0x0f3a036f}, }, {[]byte("contents"), 8, []string{ "d1b2a59fbea7e20077af9f91b27e95e865061b270be03ff539ab3b73587882e8"}, []uint32{0x0f3a036f}, }, {[]byte("contents"), 7, []string{ "ed7002b439e9ac845f22357d822bac1444730fbdb6016d3ec9432297b9ec9f73", "043a718774c572bd8a25adbeb1bfcd5c0256ae11cecf9f9c3f925d0e52beaf89"}, []uint32{0x0bcb02fc, 0x00740074}, }, {[]byte("contents"), 3, []string{ "1143da2bc54c495c4be31d3868785d39ffdfd56df5668f0645d8f14d47647952", "e4432baa90819aaef51d2a7f8e148bf7e679610f3173752fabb4dcb2d0f418d3", "44ad63f60af0f6db6fdde6d5186ef78176367df261fa06be3079b6c80c8adba4"}, []uint32{0x02780141, 0x02970148, 0x015d00e8}, }, {[]byte("conconts"), 3, []string{ "1143da2bc54c495c4be31d3868785d39ffdfd56df5668f0645d8f14d47647952", "1143da2bc54c495c4be31d3868785d39ffdfd56df5668f0645d8f14d47647952", "44ad63f60af0f6db6fdde6d5186ef78176367df261fa06be3079b6c80c8adba4"}, []uint32{0x02780141, 0x02780141, 0x015d00e8}, }, {[]byte("contenten"), 3, []string{ "1143da2bc54c495c4be31d3868785d39ffdfd56df5668f0645d8f14d47647952", "e4432baa90819aaef51d2a7f8e148bf7e679610f3173752fabb4dcb2d0f418d3", "e4432baa90819aaef51d2a7f8e148bf7e679610f3173752fabb4dcb2d0f418d3"}, []uint32{0x02780141, 0x02970148, 0x02970148}, }, } func TestBlocks(t *testing.T) { for testNo, test := range blocksTestData { buf := bytes.NewBuffer(test.data) blocks, err := Blocks(context.TODO(), buf, test.blocksize, -1, nil, true) if err != nil { t.Fatal(err) } if l := len(blocks); l != len(test.hash) { t.Fatalf("%d: Incorrect number of blocks %d != %d", testNo, l, len(test.hash)) } else { i := 0 for off := int64(0); off < int64(len(test.data)); off += int64(test.blocksize) { if blocks[i].Offset != off { t.Errorf("%d/%d: Incorrect offset %d != %d", testNo, i, blocks[i].Offset, off) } bs := test.blocksize if rem := len(test.data) - int(off); bs > rem { bs = rem } if int(blocks[i].Size) != bs { t.Errorf("%d/%d: Incorrect length %d != %d", testNo, i, blocks[i].Size, bs) } if h := fmt.Sprintf("%x", blocks[i].Hash); h != test.hash[i] { t.Errorf("%d/%d: Incorrect block hash %q != %q", testNo, i, h, test.hash[i]) } if h := blocks[i].WeakHash; h != test.weakhash[i] { t.Errorf("%d/%d: Incorrect block weakhash 0x%08x != 0x%08x", testNo, i, h, test.weakhash[i]) } i++ } } } } func TestAdler32Variants(t *testing.T) { // Verify that the two adler32 functions give matching results for a few // different blocks of data. hf1 := origAdler32.New() hf2 := rollingAdler32.New() checkFn := func(data []byte) bool { hf1.Write(data) sum1 := hf1.Sum32() hf2.Write(data) sum2 := hf2.Sum32() hf1.Reset() hf2.Reset() return sum1 == sum2 } // protocol block sized data data := make([]byte, protocol.MinBlockSize) for i := 0; i < 5; i++ { rand.Read(data) if !checkFn(data) { t.Errorf("Hash mismatch on block sized data") } } // random small blocks if err := quick.Check(checkFn, nil); err != nil { t.Error(err) } // rolling should have the same result as the individual blocks // themselves. Which is not the same as the original non-rollind adler32 // blocks. windowSize := 128 hf3 := rollingAdler32.New() hf3.Write(data[:windowSize]) for i := windowSize; i < len(data); i++ { if i%windowSize == 0 { // let the reference function catch up hf2.Reset() hf2.Write(data[i-windowSize : i]) // verify that they are in sync with the rolling function sum2 := hf2.Sum32() sum3 := hf3.Sum32() t.Logf("At i=%d, sum2=%08x, sum3=%08x", i, sum2, sum3) if sum2 != sum3 { t.Errorf("Mismatch after roll; i=%d, sum2=%08x, sum3=%08x", i, sum2, sum3) break } } hf3.Roll(data[i]) } } func BenchmarkValidate(b *testing.B) { type block struct { data []byte hash [sha256.Size]byte weakhash uint32 } var blocks []block const blocksPerType = 100 r := mrand.New(mrand.NewSource(0x136bea689e851)) // Valid blocks. for i := 0; i < blocksPerType; i++ { var b block b.data = make([]byte, 128<<10) r.Read(b.data[:]) b.hash = sha256.Sum256(b.data[:]) b.weakhash = origAdler32.Checksum(b.data[:]) blocks = append(blocks, b) } // Blocks where the hash matches, but the weakhash doesn't. for i := 0; i < blocksPerType; i++ { var b block b.data = make([]byte, 128<<10) r.Read(b.data[:]) b.hash = sha256.Sum256(b.data[:]) b.weakhash = 1 // Zeros causes Validate to skip the weakhash. blocks = append(blocks, b) } b.ReportAllocs() b.ResetTimer() for i := 0; i < b.N; i++ { for _, b := range blocks { Validate(b.data[:], b.hash[:], b.weakhash) } } }