// Copyright 2016 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 whisperv5
import (
"crypto/ecdsa"
"sync"
"github.com/ethereum/go-ethereum/common"
)
type Filter struct {
Src *ecdsa.PublicKey // Sender of the message
KeyAsym *ecdsa.PrivateKey // Private Key of recipient
KeySym []byte // Key associated with the Topic
Topics []TopicType // Topics to filter messages with
PoW float64 // Proof of work as described in the Whisper spec
AcceptP2P bool // Indicates whether this filter is interested in direct peer-to-peer messages
SymKeyHash common.Hash // The Keccak256Hash of the symmetric key, needed for optimization
Messages map[common.Hash]*ReceivedMessage
mutex sync.RWMutex
}
type Filters struct {
id int
watchers map[int]*Filter
whisper *Whisper
mutex sync.RWMutex
}
func NewFilters(w *Whisper) *Filters {
return &Filters{
watchers: make(map[int]*Filter),
whisper: w,
}
}
func (fs *Filters) Install(watcher *Filter) int {
if watcher.Messages == nil {
watcher.Messages = make(map[common.Hash]*ReceivedMessage)
}
fs.mutex.Lock()
defer fs.mutex.Unlock()
fs.watchers[fs.id] = watcher
ret := fs.id
fs.id++
return ret
}
func (fs *Filters) Uninstall(id int) {
fs.mutex.Lock()
defer fs.mutex.Unlock()
delete(fs.watchers, id)
}
func (fs *Filters) Get(i int) *Filter {
fs.mutex.RLock()
defer fs.mutex.RUnlock()
return fs.watchers[i]
}
func (fs *Filters) NotifyWatchers(env *Envelope, messageCode uint64) {
fs.mutex.RLock()
var msg *ReceivedMessage
for _, watcher := range fs.watchers {
if messageCode == p2pCode && !watcher.AcceptP2P {
continue
}
match := false
if msg != nil {
match = watcher.MatchMessage(msg)
} else {
match = watcher.MatchEnvelope(env)
if match {
msg = env.Open(watcher)
}
}
if match && msg != nil {
watcher.Trigger(msg)
}
}
fs.mutex.RUnlock() // we need to unlock before calling addDecryptedMessage
if msg != nil {
fs.whisper.addDecryptedMessage(msg)
}
}
func (f *Filter) expectsAsymmetricEncryption() bool {
return f.KeyAsym != nil
}
func (f *Filter) expectsSymmetricEncryption() bool {
return f.KeySym != nil
}
func (f *Filter) Trigger(msg *ReceivedMessage) {
f.mutex.Lock()
defer f.mutex.Unlock()
if _, exist := f.Messages[msg.EnvelopeHash]; !exist {
f.Messages[msg.EnvelopeHash] = msg
}
}
func (f *Filter) Retrieve() (all []*ReceivedMessage) {
f.mutex.Lock()
defer f.mutex.Unlock()
all = make([]*ReceivedMessage, 0, len(f.Messages))
for _, msg := range f.Messages {
all = append(all, msg)
}
f.Messages = make(map[common.Hash]*ReceivedMessage) // delete old messages
return all
}
func (f *Filter) MatchMessage(msg *ReceivedMessage) bool {
if f.PoW > 0 && msg.PoW < f.PoW {
return false
}
if f.Src != nil && !isPubKeyEqual(msg.Src, f.Src) {
return false
}
if f.expectsAsymmetricEncryption() && msg.isAsymmetricEncryption() {
// if Dst match, ignore the topic
return isPubKeyEqual(&f.KeyAsym.PublicKey, msg.Dst)
} else if f.expectsSymmetricEncryption() && msg.isSymmetricEncryption() {
// check if that both the key and the topic match
if f.SymKeyHash == msg.SymKeyHash {
for _, t := range f.Topics {
if t == msg.Topic {
return true
}
}
return false
}
}
return false
}
func (f *Filter) MatchEnvelope(envelope *Envelope) bool {
if f.PoW > 0 && envelope.pow < f.PoW {
return false
}
encryptionMethodMatch := false
if f.expectsAsymmetricEncryption() && envelope.isAsymmetric() {
encryptionMethodMatch = true
if f.Topics == nil {
// wildcard
return true
}
} else if f.expectsSymmetricEncryption() && envelope.IsSymmetric() {
encryptionMethodMatch = true
}
if encryptionMethodMatch {
for _, t := range f.Topics {
if t == envelope.Topic {
return true
}
}
}
return false
}
func isPubKeyEqual(a, b *ecdsa.PublicKey) bool {
if !ValidatePublicKey(a) {
return false
} else if !ValidatePublicKey(b) {
return false
}
// the Curve is always the same, just compare the points
return a.X.Cmp(b.X) == 0 && a.Y.Cmp(b.Y) == 0
}
