path: root/eth/protocol.go

// Copyright 2014 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 eth

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 (
    eth61 = 61
    eth62 = 62
    eth63 = 63
)

// Supported versions of the eth protocol (first is primary).
var ProtocolVersions = []uint{eth63, eth62, eth61}

// Number of implemented message corresponding to different protocol versions.
var ProtocolLengths = []uint64{17, 8, 9}

const (
    NetworkId          = 1
    ProtocolMaxMsgSize = 10 * 1024 * 1024 // Maximum cap on the size of a protocol message
)

// eth protocol message codes
const (
    // Protocol messages belonging to eth/61
    StatusMsg                   = 0x00
    NewBlockHashesMsg           = 0x01
    TxMsg                       = 0x02
    GetBlockHashesMsg           = 0x03
    BlockHashesMsg              = 0x04
    GetBlocksMsg                = 0x05
    BlocksMsg                   = 0x06
    NewBlockMsg                 = 0x07
    GetBlockHashesFromNumberMsg = 0x08

    // Protocol messages belonging to eth/62 (new protocol from scratch)
    // StatusMsg          = 0x00 (uncomment after eth/61 deprecation)
    // NewBlockHashesMsg  = 0x01 (uncomment after eth/61 deprecation)
    // TxMsg              = 0x02 (uncomment after eth/61 deprecation)
    GetBlockHeadersMsg = 0x03
    BlockHeadersMsg    = 0x04
    GetBlockBodiesMsg  = 0x05
    BlockBodiesMsg     = 0x06
    //  NewBlockMsg       = 0x07 (uncomment after eth/61 deprecation)

    // Protocol messages belonging to eth/63
    GetNodeDataMsg = 0x0d
    NodeDataMsg    = 0x0e
    GetReceiptsMsg = 0x0f
    ReceiptsMsg    = 0x10
)

type errCode int

const (
    ErrMsgTooLarge = iota
    ErrDecode
    ErrInvalidMsgCode
    ErrProtocolVersionMismatch
    ErrNetworkIdMismatch
    ErrGenesisBlockMismatch
    ErrNoStatusMsg
    ErrExtraStatusMsg
    ErrSuspendedPeer
)

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",
}

type txPool interface {
    // AddTransactions should add the given transactions to the pool.
    AddTransactions([]*types.Transaction)

    // GetTransactions should return pending transactions.
    // The slice should be modifiable by the caller.
    GetTransactions() types.Transactions
}

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)
}

// statusData is the network packet for the status message.
type statusData struct {
    ProtocolVersion uint32
    NetworkId       uint32
    TD              *big.Int
    CurrentBlock    common.Hash
    GenesisBlock    common.Hash
}

// newBlockHashesData is the network packet for the block announcements.
type newBlockHashesData []struct {
    Hash   common.Hash // Hash of one particular block being announced
    Number uint64      // Number 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
}

// getBlockHashesFromNumberData is the network packet for the number based hash
// retrieval.
type getBlockHashesFromNumberData struct {
    Number uint64
    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
}

// blockBody represents the data content of a single block.
type blockBody struct {
    Transactions []*types.Transaction // Transactions contained within a block
    Uncles       []*types.Header      // Uncles contained within a block
}

// blockBodiesData is the network packet for block content distribution.
type blockBodiesData []*blockBody

// nodeDataData is the network response packet for a node data retrieval.
type nodeDataData []struct {
    Value []byte
}