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// 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 pss
import (
"encoding/json"
"fmt"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/swarm/storage"
whisper "github.com/ethereum/go-ethereum/whisper/whisperv5"
)
const (
defaultWhisperTTL = 6000
)
const (
pssControlSym = 1
pssControlRaw = 1 << 1
)
var (
topicHashMutex = sync.Mutex{}
topicHashFunc = storage.MakeHashFunc("SHA256")()
rawTopic = Topic{}
)
// Topic is the PSS encapsulation of the Whisper topic type
type Topic whisper.TopicType
func (t *Topic) String() string {
return hexutil.Encode(t[:])
}
// MarshalJSON implements the json.Marshaler interface
func (t Topic) MarshalJSON() (b []byte, err error) {
return json.Marshal(t.String())
}
// MarshalJSON implements the json.Marshaler interface
func (t *Topic) UnmarshalJSON(input []byte) error {
topicbytes, err := hexutil.Decode(string(input[1 : len(input)-1]))
if err != nil {
return err
}
copy(t[:], topicbytes)
return nil
}
// PssAddress is an alias for []byte. It represents a variable length address
type PssAddress []byte
// MarshalJSON implements the json.Marshaler interface
func (a PssAddress) MarshalJSON() ([]byte, error) {
return json.Marshal(hexutil.Encode(a[:]))
}
// UnmarshalJSON implements the json.Marshaler interface
func (a *PssAddress) UnmarshalJSON(input []byte) error {
b, err := hexutil.Decode(string(input[1 : len(input)-1]))
if err != nil {
return err
}
for _, bb := range b {
*a = append(*a, bb)
}
return nil
}
// holds the digest of a message used for caching
type pssDigest [digestLength]byte
// conceals bitwise operations on the control flags byte
type msgParams struct {
raw bool
sym bool
}
func newMsgParamsFromBytes(paramBytes []byte) *msgParams {
if len(paramBytes) != 1 {
return nil
}
return &msgParams{
raw: paramBytes[0]&pssControlRaw > 0,
sym: paramBytes[0]&pssControlSym > 0,
}
}
func (m *msgParams) Bytes() (paramBytes []byte) {
var b byte
if m.raw {
b |= pssControlRaw
}
if m.sym {
b |= pssControlSym
}
paramBytes = append(paramBytes, b)
return paramBytes
}
// PssMsg encapsulates messages transported over pss.
type PssMsg struct {
To []byte
Control []byte
Expire uint32
Payload *whisper.Envelope
}
func newPssMsg(param *msgParams) *PssMsg {
return &PssMsg{
Control: param.Bytes(),
}
}
// message is flagged as raw / external encryption
func (msg *PssMsg) isRaw() bool {
return msg.Control[0]&pssControlRaw > 0
}
// message is flagged as symmetrically encrypted
func (msg *PssMsg) isSym() bool {
return msg.Control[0]&pssControlSym > 0
}
// serializes the message for use in cache
func (msg *PssMsg) serialize() []byte {
rlpdata, _ := rlp.EncodeToBytes(struct {
To []byte
Payload *whisper.Envelope
}{
To: msg.To,
Payload: msg.Payload,
})
return rlpdata
}
// String representation of PssMsg
func (msg *PssMsg) String() string {
return fmt.Sprintf("PssMsg: Recipient: %x", common.ToHex(msg.To))
}
// Signature for a message handler function for a PssMsg
//
// Implementations of this type are passed to Pss.Register together with a topic,
type Handler func(msg []byte, p *p2p.Peer, asymmetric bool, keyid string) error
// the stateStore handles saving and loading PSS peers and their corresponding keys
// it is currently unimplemented
type stateStore struct {
values map[string][]byte
}
func newStateStore() *stateStore {
return &stateStore{values: make(map[string][]byte)}
}
func (store *stateStore) Load(key string) ([]byte, error) {
return nil, nil
}
func (store *stateStore) Save(key string, v []byte) error {
return nil
}
// BytesToTopic hashes an arbitrary length byte slice and truncates it to the length of a topic, using only the first bytes of the digest
func BytesToTopic(b []byte) Topic {
topicHashMutex.Lock()
defer topicHashMutex.Unlock()
topicHashFunc.Reset()
topicHashFunc.Write(b)
return Topic(whisper.BytesToTopic(topicHashFunc.Sum(nil)))
}
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