les: light client protocol and API

les/protocol.go

@@ -0,0 +1,198 @@
+// Copyright 2015 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 les implements the Light Ethereum Subprotocol.
+package les
+
+import (
+	"fmt"
+	"io"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// Constants to match up protocol versions and messages
+const (
+	lpv1 = 1
+)
+
+// Supported versions of the les protocol (first is primary).
+var ProtocolVersions = []uint{lpv1}
+
+// Number of implemented message corresponding to different protocol versions.
+var ProtocolLengths = []uint64{15}
+
+const (
+	NetworkId          = 1
+	ProtocolMaxMsgSize = 10 * 1024 * 1024 // Maximum cap on the size of a protocol message
+)
+
+// les protocol message codes
+const (
+	// Protocol messages belonging to LPV1
+	StatusMsg          = 0x00
+	AnnounceMsg        = 0x01
+	GetBlockHeadersMsg = 0x02
+	BlockHeadersMsg    = 0x03
+	GetBlockBodiesMsg  = 0x04
+	BlockBodiesMsg     = 0x05
+	GetReceiptsMsg     = 0x06
+	ReceiptsMsg        = 0x07
+	GetProofsMsg       = 0x08
+	ProofsMsg          = 0x09
+	GetCodeMsg         = 0x0a
+	CodeMsg            = 0x0b
+	SendTxMsg          = 0x0c
+	GetHeaderProofsMsg = 0x0d
+	HeaderProofsMsg    = 0x0e
+)
+
+type errCode int
+
+const (
+	ErrMsgTooLarge = iota
+	ErrDecode
+	ErrInvalidMsgCode
+	ErrProtocolVersionMismatch
+	ErrNetworkIdMismatch
+	ErrGenesisBlockMismatch
+	ErrNoStatusMsg
+	ErrExtraStatusMsg
+	ErrSuspendedPeer
+	ErrUselessPeer
+	ErrRequestRejected
+	ErrUnexpectedResponse
+	ErrInvalidResponse
+	ErrTooManyTimeouts
+	ErrHandshakeMissingKey
+)
+
+func (e errCode) String() string {
+	return errorToString[int(e)]
+}
+
+// XXX change once legacy code is out
+var errorToString = map[int]string{
+	ErrMsgTooLarge:             "Message too long",
+	ErrDecode:                  "Invalid message",
+	ErrInvalidMsgCode:          "Invalid message code",
+	ErrProtocolVersionMismatch: "Protocol version mismatch",
+	ErrNetworkIdMismatch:       "NetworkId mismatch",
+	ErrGenesisBlockMismatch:    "Genesis block mismatch",
+	ErrNoStatusMsg:             "No status message",
+	ErrExtraStatusMsg:          "Extra status message",
+	ErrSuspendedPeer:           "Suspended peer",
+	ErrRequestRejected:         "Request rejected",
+	ErrUnexpectedResponse:      "Unexpected response",
+	ErrInvalidResponse:         "Invalid response",
+	ErrTooManyTimeouts:         "Too many request timeouts",
+	ErrHandshakeMissingKey:     "Key missing from handshake message",
+}
+
+type chainManager interface {
+	GetBlockHashesFromHash(hash common.Hash, amount uint64) (hashes []common.Hash)
+	GetBlock(hash common.Hash) (block *types.Block)
+	Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash)
+}
+
+// announceData is the network packet for the block announcements.
+type announceData struct {
+	Hash       common.Hash // Hash of one particular block being announced
+	Number     uint64      // Number of one particular block being announced
+	Td         *big.Int    // Total difficulty of one particular block being announced
+	ReorgDepth uint64
+	Update     keyValueList
+
+	haveHeaders uint64 // we have the headers of the remote peer's chain up to this number
+	headKnown   bool
+	requested   bool
+	next        *announceData
+}
+
+type blockInfo struct {
+	Hash   common.Hash // Hash of one particular block being announced
+	Number uint64      // Number of one particular block being announced
+	Td     *big.Int    // Total difficulty of one particular block being announced
+}
+
+// getBlockHashesData is the network packet for the hash based hash retrieval.
+type getBlockHashesData struct {
+	Hash   common.Hash
+	Amount uint64
+}
+
+// getBlockHeadersData represents a block header query.
+type getBlockHeadersData struct {
+	Origin  hashOrNumber // Block from which to retrieve headers
+	Amount  uint64       // Maximum number of headers to retrieve
+	Skip    uint64       // Blocks to skip between consecutive headers
+	Reverse bool         // Query direction (false = rising towards latest, true = falling towards genesis)
+}
+
+// hashOrNumber is a combined field for specifying an origin block.
+type hashOrNumber struct {
+	Hash   common.Hash // Block hash from which to retrieve headers (excludes Number)
+	Number uint64      // Block hash from which to retrieve headers (excludes Hash)
+}
+
+// EncodeRLP is a specialized encoder for hashOrNumber to encode only one of the
+// two contained union fields.
+func (hn *hashOrNumber) EncodeRLP(w io.Writer) error {
+	if hn.Hash == (common.Hash{}) {
+		return rlp.Encode(w, hn.Number)
+	}
+	if hn.Number != 0 {
+		return fmt.Errorf("both origin hash (%x) and number (%d) provided", hn.Hash, hn.Number)
+	}
+	return rlp.Encode(w, hn.Hash)
+}
+
+// DecodeRLP is a specialized decoder for hashOrNumber to decode the contents
+// into either a block hash or a block number.
+func (hn *hashOrNumber) DecodeRLP(s *rlp.Stream) error {
+	_, size, _ := s.Kind()
+	origin, err := s.Raw()
+	if err == nil {
+		switch {
+		case size == 32:
+			err = rlp.DecodeBytes(origin, &hn.Hash)
+		case size <= 8:
+			err = rlp.DecodeBytes(origin, &hn.Number)
+		default:
+			err = fmt.Errorf("invalid input size %d for origin", size)
+		}
+	}
+	return err
+}
+
+// newBlockData is the network packet for the block propagation message.
+type newBlockData struct {
+	Block *types.Block
+	TD    *big.Int
+}
+
+// blockBodiesData is the network packet for block content distribution.
+type blockBodiesData []*types.Body
+
+// CodeData is the network response packet for a node data retrieval.
+type CodeData []struct {
+	Value []byte
+}
+
+type proofsData [][]rlp.RawValue