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author | ethersphere <thesw@rm.eth> | 2018-06-20 20:06:27 +0800 |
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committer | ethersphere <thesw@rm.eth> | 2018-06-22 03:10:31 +0800 |
commit | e187711c6545487d4cac3701f0f506bb536234e2 (patch) | |
tree | d2f6150f70b84b36e49a449082aeda267b4b9046 /swarm/storage/hasherstore.go | |
parent | 574378edb50c907b532946a1d4654dbd6701b20a (diff) | |
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swarm: network rewrite merge
Diffstat (limited to 'swarm/storage/hasherstore.go')
-rw-r--r-- | swarm/storage/hasherstore.go | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/swarm/storage/hasherstore.go b/swarm/storage/hasherstore.go new file mode 100644 index 000000000..e659c3681 --- /dev/null +++ b/swarm/storage/hasherstore.go @@ -0,0 +1,229 @@ +// Copyright 2018 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 storage + +import ( + "fmt" + "sync" + + "github.com/ethereum/go-ethereum/crypto/sha3" + "github.com/ethereum/go-ethereum/swarm/storage/encryption" +) + +type chunkEncryption struct { + spanEncryption encryption.Encryption + dataEncryption encryption.Encryption +} + +type hasherStore struct { + store ChunkStore + hashFunc SwarmHasher + chunkEncryption *chunkEncryption + hashSize int // content hash size + refSize int64 // reference size (content hash + possibly encryption key) + wg *sync.WaitGroup + closed chan struct{} +} + +func newChunkEncryption(chunkSize, refSize int64) *chunkEncryption { + return &chunkEncryption{ + spanEncryption: encryption.New(0, uint32(chunkSize/refSize), sha3.NewKeccak256), + dataEncryption: encryption.New(int(chunkSize), 0, sha3.NewKeccak256), + } +} + +// NewHasherStore creates a hasherStore object, which implements Putter and Getter interfaces. +// With the HasherStore you can put and get chunk data (which is just []byte) into a ChunkStore +// and the hasherStore will take core of encryption/decryption of data if necessary +func NewHasherStore(chunkStore ChunkStore, hashFunc SwarmHasher, toEncrypt bool) *hasherStore { + var chunkEncryption *chunkEncryption + + hashSize := hashFunc().Size() + refSize := int64(hashSize) + if toEncrypt { + refSize += encryption.KeyLength + chunkEncryption = newChunkEncryption(DefaultChunkSize, refSize) + } + + return &hasherStore{ + store: chunkStore, + hashFunc: hashFunc, + chunkEncryption: chunkEncryption, + hashSize: hashSize, + refSize: refSize, + wg: &sync.WaitGroup{}, + closed: make(chan struct{}), + } +} + +// Put stores the chunkData into the ChunkStore of the hasherStore and returns the reference. +// If hasherStore has a chunkEncryption object, the data will be encrypted. +// Asynchronous function, the data will not necessarily be stored when it returns. +func (h *hasherStore) Put(chunkData ChunkData) (Reference, error) { + c := chunkData + size := chunkData.Size() + var encryptionKey encryption.Key + if h.chunkEncryption != nil { + var err error + c, encryptionKey, err = h.encryptChunkData(chunkData) + if err != nil { + return nil, err + } + } + chunk := h.createChunk(c, size) + + h.storeChunk(chunk) + + return Reference(append(chunk.Addr, encryptionKey...)), nil +} + +// Get returns data of the chunk with the given reference (retrieved from the ChunkStore of hasherStore). +// If the data is encrypted and the reference contains an encryption key, it will be decrypted before +// return. +func (h *hasherStore) Get(ref Reference) (ChunkData, error) { + key, encryptionKey, err := parseReference(ref, h.hashSize) + if err != nil { + return nil, err + } + toDecrypt := (encryptionKey != nil) + + chunk, err := h.store.Get(key) + if err != nil { + return nil, err + } + + chunkData := chunk.SData + if toDecrypt { + var err error + chunkData, err = h.decryptChunkData(chunkData, encryptionKey) + if err != nil { + return nil, err + } + } + return chunkData, nil +} + +// Close indicates that no more chunks will be put with the hasherStore, so the Wait +// function can return when all the previously put chunks has been stored. +func (h *hasherStore) Close() { + close(h.closed) +} + +// Wait returns when +// 1) the Close() function has been called and +// 2) all the chunks which has been Put has been stored +func (h *hasherStore) Wait() { + <-h.closed + h.wg.Wait() +} + +func (h *hasherStore) createHash(chunkData ChunkData) Address { + hasher := h.hashFunc() + hasher.ResetWithLength(chunkData[:8]) // 8 bytes of length + hasher.Write(chunkData[8:]) // minus 8 []byte length + return hasher.Sum(nil) +} + +func (h *hasherStore) createChunk(chunkData ChunkData, chunkSize int64) *Chunk { + hash := h.createHash(chunkData) + chunk := NewChunk(hash, nil) + chunk.SData = chunkData + chunk.Size = chunkSize + + return chunk +} + +func (h *hasherStore) encryptChunkData(chunkData ChunkData) (ChunkData, encryption.Key, error) { + if len(chunkData) < 8 { + return nil, nil, fmt.Errorf("Invalid ChunkData, min length 8 got %v", len(chunkData)) + } + + encryptionKey, err := encryption.GenerateRandomKey() + if err != nil { + return nil, nil, err + } + + encryptedSpan, err := h.chunkEncryption.spanEncryption.Encrypt(chunkData[:8], encryptionKey) + if err != nil { + return nil, nil, err + } + encryptedData, err := h.chunkEncryption.dataEncryption.Encrypt(chunkData[8:], encryptionKey) + if err != nil { + return nil, nil, err + } + c := make(ChunkData, len(encryptedSpan)+len(encryptedData)) + copy(c[:8], encryptedSpan) + copy(c[8:], encryptedData) + return c, encryptionKey, nil +} + +func (h *hasherStore) decryptChunkData(chunkData ChunkData, encryptionKey encryption.Key) (ChunkData, error) { + if len(chunkData) < 8 { + return nil, fmt.Errorf("Invalid ChunkData, min length 8 got %v", len(chunkData)) + } + + decryptedSpan, err := h.chunkEncryption.spanEncryption.Decrypt(chunkData[:8], encryptionKey) + if err != nil { + return nil, err + } + + decryptedData, err := h.chunkEncryption.dataEncryption.Decrypt(chunkData[8:], encryptionKey) + if err != nil { + return nil, err + } + + // removing extra bytes which were just added for padding + length := ChunkData(decryptedSpan).Size() + for length > DefaultChunkSize { + length = length + (DefaultChunkSize - 1) + length = length / DefaultChunkSize + length *= h.refSize + } + + c := make(ChunkData, length+8) + copy(c[:8], decryptedSpan) + copy(c[8:], decryptedData[:length]) + + return c[:length+8], nil +} + +func (h *hasherStore) RefSize() int64 { + return h.refSize +} + +func (h *hasherStore) storeChunk(chunk *Chunk) { + h.wg.Add(1) + go func() { + <-chunk.dbStoredC + h.wg.Done() + }() + h.store.Put(chunk) +} + +func parseReference(ref Reference, hashSize int) (Address, encryption.Key, error) { + encryptedKeyLength := hashSize + encryption.KeyLength + switch len(ref) { + case KeyLength: + return Address(ref), nil, nil + case encryptedKeyLength: + encKeyIdx := len(ref) - encryption.KeyLength + return Address(ref[:encKeyIdx]), encryption.Key(ref[encKeyIdx:]), nil + default: + return nil, nil, fmt.Errorf("Invalid reference length, expected %v or %v got %v", hashSize, encryptedKeyLength, len(ref)) + } + +} |