1 files changed, 239 insertions, 0 deletions
diff --git a/whisper/whisperv6/filter.go b/whisper/whisperv6/filter.go
new file mode 100644
index 000000000..5cb371b7d
--- /dev/null
+++ b/whisper/whisperv6/filter.go
@@ -0,0 +1,239 @@
+// 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 whisperv6
+
+import (
+	"crypto/ecdsa"
+	"fmt"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+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     [][]byte          // Topics to filter messages with
+	PoW        float64           // Proof of work as described in the Whisper spec
+	AllowP2P   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 {
+	watchers map[string]*Filter
+	whisper  *Whisper
+	mutex    sync.RWMutex
+}
+
+func NewFilters(w *Whisper) *Filters {
+	return &Filters{
+		watchers: make(map[string]*Filter),
+		whisper:  w,
+	}
+}
+
+func (fs *Filters) Install(watcher *Filter) (string, error) {
+	if watcher.Messages == nil {
+		watcher.Messages = make(map[common.Hash]*ReceivedMessage)
+	}
+
+	id, err := GenerateRandomID()
+	if err != nil {
+		return "", err
+	}
+
+	fs.mutex.Lock()
+	defer fs.mutex.Unlock()
+
+	if fs.watchers[id] != nil {
+		return "", fmt.Errorf("failed to generate unique ID")
+	}
+
+	if watcher.expectsSymmetricEncryption() {
+		watcher.SymKeyHash = crypto.Keccak256Hash(watcher.KeySym)
+	}
+
+	fs.watchers[id] = watcher
+	return id, err
+}
+
+func (fs *Filters) Uninstall(id string) bool {
+	fs.mutex.Lock()
+	defer fs.mutex.Unlock()
+	if fs.watchers[id] != nil {
+		delete(fs.watchers, id)
+		return true
+	}
+	return false
+}
+
+func (fs *Filters) Get(id string) *Filter {
+	fs.mutex.RLock()
+	defer fs.mutex.RUnlock()
+	return fs.watchers[id]
+}
+
+func (fs *Filters) NotifyWatchers(env *Envelope, p2pMessage bool) {
+	var msg *ReceivedMessage
+
+	fs.mutex.RLock()
+	defer fs.mutex.RUnlock()
+
+	i := -1 // only used for logging info
+	for _, watcher := range fs.watchers {
+		i++
+		if p2pMessage && !watcher.AllowP2P {
+			log.Trace(fmt.Sprintf("msg [%x], filter [%d]: p2p messages are not allowed", env.Hash(), i))
+			continue
+		}
+
+		var match bool
+		if msg != nil {
+			match = watcher.MatchMessage(msg)
+		} else {
+			match = watcher.MatchEnvelope(env)
+			if match {
+				msg = env.Open(watcher)
+				if msg == nil {
+					log.Trace("processing message: failed to open", "message", env.Hash().Hex(), "filter", i)
+				}
+			} else {
+				log.Trace("processing message: does not match", "message", env.Hash().Hex(), "filter", i)
+			}
+		}
+
+		if match && msg != nil {
+			log.Trace("processing message: decrypted", "hash", env.Hash().Hex())
+			if watcher.Src == nil || IsPubKeyEqual(msg.Src, watcher.Src) {
+				watcher.Trigger(msg)
+			}
+		}
+	}
+}
+
+func (f *Filter) processEnvelope(env *Envelope) *ReceivedMessage {
+	if f.MatchEnvelope(env) {
+		msg := env.Open(f)
+		if msg != nil {
+			return msg
+		} else {
+			log.Trace("processing envelope: failed to open", "hash", env.Hash().Hex())
+		}
+	} else {
+		log.Trace("processing envelope: does not match", "hash", env.Hash().Hex())
+	}
+	return nil
+}
+
+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.expectsAsymmetricEncryption() && msg.isAsymmetricEncryption() {
+		return IsPubKeyEqual(&f.KeyAsym.PublicKey, msg.Dst) && f.MatchTopic(msg.Topic)
+	} else if f.expectsSymmetricEncryption() && msg.isSymmetricEncryption() {
+		return f.SymKeyHash == msg.SymKeyHash && f.MatchTopic(msg.Topic)
+	}
+	return false
+}
+
+func (f *Filter) MatchEnvelope(envelope *Envelope) bool {
+	if f.PoW > 0 && envelope.pow < f.PoW {
+		return false
+	}
+
+	if f.expectsAsymmetricEncryption() && envelope.isAsymmetric() {
+		return f.MatchTopic(envelope.Topic)
+	} else if f.expectsSymmetricEncryption() && envelope.IsSymmetric() {
+		return f.MatchTopic(envelope.Topic)
+	}
+	return false
+}
+
+func (f *Filter) MatchTopic(topic TopicType) bool {
+	if len(f.Topics) == 0 {
+		// any topic matches
+		return true
+	}
+
+	for _, bt := range f.Topics {
+		if matchSingleTopic(topic, bt) {
+			return true
+		}
+	}
+	return false
+}
+
+func matchSingleTopic(topic TopicType, bt []byte) bool {
+	if len(bt) > 4 {
+		bt = bt[:4]
+	}
+
+	for j, b := range bt {
+		if topic[j] != b {
+			return false
+		}
+	}
+	return true
+}
+
+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
+}