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))
+	}
+
+}