swarm/pss: refactoring (#19110)

* swarm/pss: split pss and keystore

* swarm/pss: moved whisper to keystore

* swarm/pss: goimports fixed

(cherry picked from commit 12ca3b172a7e1b2b63ef2369e8dc37c75144c81f)

3 files changed, 293 insertions, 256 deletions

diff --git a/swarm/pss/keystore.go b/swarm/pss/keystore.go
new file mode 100644
index 000000000..510d21bcf
--- /dev/null
+++ b/swarm/pss/keystore.go
@@ -0,0 +1,281 @@
+// Copyright 2019 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 (
+	"crypto/ecdsa"
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/swarm/log"
+	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
+)
+
+type KeyStore struct {
+	w *whisper.Whisper // key and encryption backend
+
+	mx                       sync.RWMutex
+	pubKeyPool               map[string]map[Topic]*pssPeer // mapping of hex public keys to peer address by topic.
+	symKeyPool               map[string]map[Topic]*pssPeer // mapping of symkeyids to peer address by topic.
+	symKeyDecryptCache       []*string                     // fast lookup of symkeys recently used for decryption; last used is on top of stack
+	symKeyDecryptCacheCursor int                           // modular cursor pointing to last used, wraps on symKeyDecryptCache array
+}
+
+func loadKeyStore() *KeyStore {
+	return &KeyStore{
+		w: whisper.New(&whisper.DefaultConfig),
+
+		pubKeyPool:         make(map[string]map[Topic]*pssPeer),
+		symKeyPool:         make(map[string]map[Topic]*pssPeer),
+		symKeyDecryptCache: make([]*string, defaultSymKeyCacheCapacity),
+	}
+}
+
+func (ks *KeyStore) isSymKeyStored(key string) bool {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	var ok bool
+	_, ok = ks.symKeyPool[key]
+	return ok
+}
+
+func (ks *KeyStore) isPubKeyStored(key string) bool {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	var ok bool
+	_, ok = ks.pubKeyPool[key]
+	return ok
+}
+
+func (ks *KeyStore) getPeerSym(symkeyid string, topic Topic) (*pssPeer, bool) {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	psp, ok := ks.symKeyPool[symkeyid][topic]
+	return psp, ok
+}
+
+func (ks *KeyStore) getPeerPub(pubkeyid string, topic Topic) (*pssPeer, bool) {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	psp, ok := ks.pubKeyPool[pubkeyid][topic]
+	return psp, ok
+}
+
+// Links a peer ECDSA public key to a topic.
+// This is required for asymmetric message exchange on the given topic.
+// The value in `address` will be used as a routing hint for the public key / topic association.
+func (ks *KeyStore) SetPeerPublicKey(pubkey *ecdsa.PublicKey, topic Topic, address PssAddress) error {
+	if err := validateAddress(address); err != nil {
+		return err
+	}
+	pubkeybytes := crypto.FromECDSAPub(pubkey)
+	if len(pubkeybytes) == 0 {
+		return fmt.Errorf("invalid public key: %v", pubkey)
+	}
+	pubkeyid := common.ToHex(pubkeybytes)
+	psp := &pssPeer{
+		address: address,
+	}
+	ks.mx.Lock()
+	if _, ok := ks.pubKeyPool[pubkeyid]; !ok {
+		ks.pubKeyPool[pubkeyid] = make(map[Topic]*pssPeer)
+	}
+	ks.pubKeyPool[pubkeyid][topic] = psp
+	ks.mx.Unlock()
+	log.Trace("added pubkey", "pubkeyid", pubkeyid, "topic", topic, "address", address)
+	return nil
+}
+
+// adds a symmetric key to the pss key pool, and optionally adds the key to the
+// collection of keys used to attempt symmetric decryption of incoming messages
+func (ks *KeyStore) addSymmetricKeyToPool(keyid string, topic Topic, address PssAddress, addtocache bool, protected bool) {
+	psp := &pssPeer{
+		address:   address,
+		protected: protected,
+	}
+	ks.mx.Lock()
+	if _, ok := ks.symKeyPool[keyid]; !ok {
+		ks.symKeyPool[keyid] = make(map[Topic]*pssPeer)
+	}
+	ks.symKeyPool[keyid][topic] = psp
+	ks.mx.Unlock()
+	if addtocache {
+		ks.symKeyDecryptCacheCursor++
+		ks.symKeyDecryptCache[ks.symKeyDecryptCacheCursor%cap(ks.symKeyDecryptCache)] = &keyid
+	}
+}
+
+// Returns all recorded topic and address combination for a specific public key
+func (ks *KeyStore) GetPublickeyPeers(keyid string) (topic []Topic, address []PssAddress, err error) {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	for t, peer := range ks.pubKeyPool[keyid] {
+		topic = append(topic, t)
+		address = append(address, peer.address)
+	}
+	return topic, address, nil
+}
+
+func (ks *KeyStore) getPeerAddress(keyid string, topic Topic) (PssAddress, error) {
+	ks.mx.RLock()
+	defer ks.mx.RUnlock()
+	if peers, ok := ks.pubKeyPool[keyid]; ok {
+		if t, ok := peers[topic]; ok {
+			return t.address, nil
+		}
+	}
+	return nil, fmt.Errorf("peer with pubkey %s, topic %x not found", keyid, topic)
+}
+
+// Attempt to decrypt, validate and unpack a symmetrically encrypted message.
+// If successful, returns the unpacked whisper ReceivedMessage struct
+// encapsulating the decrypted message, and the whisper backend id
+// of the symmetric key used to decrypt the message.
+// It fails if decryption of the message fails or if the message is corrupted.
+func (ks *KeyStore) processSym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
+	metrics.GetOrRegisterCounter("pss.process.sym", nil).Inc(1)
+
+	for i := ks.symKeyDecryptCacheCursor; i > ks.symKeyDecryptCacheCursor-cap(ks.symKeyDecryptCache) && i > 0; i-- {
+		symkeyid := ks.symKeyDecryptCache[i%cap(ks.symKeyDecryptCache)]
+		symkey, err := ks.w.GetSymKey(*symkeyid)
+		if err != nil {
+			continue
+		}
+		recvmsg, err := envelope.OpenSymmetric(symkey)
+		if err != nil {
+			continue
+		}
+		if !recvmsg.ValidateAndParse() {
+			return nil, "", nil, errors.New("symmetrically encrypted message has invalid signature or is corrupt")
+		}
+		var from PssAddress
+		ks.mx.RLock()
+		if ks.symKeyPool[*symkeyid][Topic(envelope.Topic)] != nil {
+			from = ks.symKeyPool[*symkeyid][Topic(envelope.Topic)].address
+		}
+		ks.mx.RUnlock()
+		ks.symKeyDecryptCacheCursor++
+		ks.symKeyDecryptCache[ks.symKeyDecryptCacheCursor%cap(ks.symKeyDecryptCache)] = symkeyid
+		return recvmsg, *symkeyid, from, nil
+	}
+	return nil, "", nil, errors.New("could not decrypt message")
+}
+
+// Attempt to decrypt, validate and unpack an asymmetrically encrypted message.
+// If successful, returns the unpacked whisper ReceivedMessage struct
+// encapsulating the decrypted message, and the byte representation of
+// the public key used to decrypt the message.
+// It fails if decryption of message fails, or if the message is corrupted.
+func (ks *Pss) processAsym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
+	metrics.GetOrRegisterCounter("pss.process.asym", nil).Inc(1)
+
+	recvmsg, err := envelope.OpenAsymmetric(ks.privateKey)
+	if err != nil {
+		return nil, "", nil, fmt.Errorf("could not decrypt message: %s", err)
+	}
+	// check signature (if signed), strip padding
+	if !recvmsg.ValidateAndParse() {
+		return nil, "", nil, errors.New("invalid message")
+	}
+	pubkeyid := common.ToHex(crypto.FromECDSAPub(recvmsg.Src))
+	var from PssAddress
+	ks.mx.RLock()
+	if ks.pubKeyPool[pubkeyid][Topic(envelope.Topic)] != nil {
+		from = ks.pubKeyPool[pubkeyid][Topic(envelope.Topic)].address
+	}
+	ks.mx.RUnlock()
+	return recvmsg, pubkeyid, from, nil
+}
+
+// Symkey garbage collection
+// a key is removed if:
+// - it is not marked as protected
+// - it is not in the incoming decryption cache
+func (ks *Pss) cleanKeys() (count int) {
+	for keyid, peertopics := range ks.symKeyPool {
+		var expiredtopics []Topic
+		for topic, psp := range peertopics {
+			if psp.protected {
+				continue
+			}
+
+			var match bool
+			for i := ks.symKeyDecryptCacheCursor; i > ks.symKeyDecryptCacheCursor-cap(ks.symKeyDecryptCache) && i > 0; i-- {
+				cacheid := ks.symKeyDecryptCache[i%cap(ks.symKeyDecryptCache)]
+				if *cacheid == keyid {
+					match = true
+				}
+			}
+			if !match {
+				expiredtopics = append(expiredtopics, topic)
+			}
+		}
+		for _, topic := range expiredtopics {
+			ks.mx.Lock()
+			delete(ks.symKeyPool[keyid], topic)
+			log.Trace("symkey cleanup deletion", "symkeyid", keyid, "topic", topic, "val", ks.symKeyPool[keyid])
+			ks.mx.Unlock()
+			count++
+		}
+	}
+	return count
+}
+
+// Automatically generate a new symkey for a topic and address hint
+func (ks *KeyStore) GenerateSymmetricKey(topic Topic, address PssAddress, addToCache bool) (string, error) {
+	keyid, err := ks.w.GenerateSymKey()
+	if err == nil {
+		ks.addSymmetricKeyToPool(keyid, topic, address, addToCache, false)
+	}
+	return keyid, err
+}
+
+// Returns a symmetric key byte sequence stored in the whisper backend by its unique id.
+// Passes on the error value from the whisper backend.
+func (ks *KeyStore) GetSymmetricKey(symkeyid string) ([]byte, error) {
+	return ks.w.GetSymKey(symkeyid)
+}
+
+// Links a peer symmetric key (arbitrary byte sequence) to a topic.
+//
+// This is required for symmetrically encrypted message exchange on the given topic.
+//
+// The key is stored in the whisper backend.
+//
+// If addtocache is set to true, the key will be added to the cache of keys
+// used to attempt symmetric decryption of incoming messages.
+//
+// Returns a string id that can be used to retrieve the key bytes
+// from the whisper backend (see pss.GetSymmetricKey())
+func (ks *KeyStore) SetSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool) (string, error) {
+	if err := validateAddress(address); err != nil {
+		return "", err
+	}
+	return ks.setSymmetricKey(key, topic, address, addtocache, true)
+}
+
+func (ks *KeyStore) setSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool, protected bool) (string, error) {
+	keyid, err := ks.w.AddSymKeyDirect(key)
+	if err == nil {
+		ks.addSymmetricKeyToPool(keyid, topic, address, addtocache, protected)
+	}
+	return keyid, err
+}
diff --git a/swarm/pss/protocol.go b/swarm/pss/protocol.go
index 5f47ee47d..7f186f615 100644
--- a/swarm/pss/protocol.go
+++ b/swarm/pss/protocol.go
@@ -228,7 +228,6 @@ func ToP2pMsg(msg []byte) (p2p.Msg, error) {
 // to link the peer to.
 // The key must exist in the pss store prior to adding the peer.
 func (p *Protocol) AddPeer(peer *p2p.Peer, topic Topic, asymmetric bool, key string) (p2p.MsgReadWriter, error) {
-	var ok bool
 	rw := &PssReadWriter{
 		Pss:   p.Pss,
 		rw:    make(chan p2p.Msg),
@@ -242,20 +241,14 @@ func (p *Protocol) AddPeer(peer *p2p.Peer, topic Topic, asymmetric bool, key str
 		rw.sendFunc = p.Pss.SendSym
 	}
 	if asymmetric {
-		p.Pss.pubKeyPoolMu.Lock()
-		_, ok = p.Pss.pubKeyPool[key]
-		p.Pss.pubKeyPoolMu.Unlock()
-		if !ok {
+		if !p.Pss.isPubKeyStored(key) {
 			return nil, fmt.Errorf("asym key does not exist: %s", key)
 		}
 		p.RWPoolMu.Lock()
 		p.pubKeyRWPool[key] = rw
 		p.RWPoolMu.Unlock()
 	} else {
-		p.Pss.symKeyPoolMu.Lock()
-		_, ok = p.Pss.symKeyPool[key]
-		p.Pss.symKeyPoolMu.Unlock()
-		if !ok {
+		if !p.Pss.isSymKeyStored(key) {
 			return nil, fmt.Errorf("symkey does not exist: %s", key)
 		}
 		p.RWPoolMu.Lock()
diff --git a/swarm/pss/pss.go b/swarm/pss/pss.go
index 4d5e4a61b..183aab04d 100644
--- a/swarm/pss/pss.go
+++ b/swarm/pss/pss.go
@@ -112,10 +112,11 @@ func (params *PssParams) WithPrivateKey(privatekey *ecdsa.PrivateKey) *PssParams
 //
 // Implements node.Service
 type Pss struct {
-	*network.Kademlia                   // we can get the Kademlia address from this
-	privateKey        *ecdsa.PrivateKey // pss can have it's own independent key
-	w                 *whisper.Whisper  // key and encryption backend
-	auxAPIs           []rpc.API         // builtins (handshake, test) can add APIs
+	*network.Kademlia // we can get the Kademlia address from this
+	*KeyStore
+
+	privateKey *ecdsa.PrivateKey // pss can have it's own independent key
+	auxAPIs    []rpc.API         // builtins (handshake, test) can add APIs
 
 	// sending and forwarding
 	fwdPool         map[string]*protocols.Peer // keep track of all peers sitting on the pssmsg routing layer
@@ -128,15 +129,6 @@ type Pss struct {
 	capstring       string
 	outbox          chan *PssMsg
 
-	// keys and peers
-	pubKeyPool                 map[string]map[Topic]*pssPeer // mapping of hex public keys to peer address by topic.
-	pubKeyPoolMu               sync.RWMutex
-	symKeyPool                 map[string]map[Topic]*pssPeer // mapping of symkeyids to peer address by topic.
-	symKeyPoolMu               sync.RWMutex
-	symKeyDecryptCache         []*string // fast lookup of symkeys recently used for decryption; last used is on top of stack
-	symKeyDecryptCacheCursor   int       // modular cursor pointing to last used, wraps on symKeyDecryptCache array
-	symKeyDecryptCacheCapacity int       // max amount of symkeys to keep.
-
 	// message handling
 	handlers         map[Topic]map[*handler]bool // topic and version based pss payload handlers. See pss.Handle()
 	handlersMu       sync.RWMutex
@@ -164,9 +156,10 @@ func NewPss(k *network.Kademlia, params *PssParams) (*Pss, error) {
 		Version: pssVersion,
 	}
 	ps := &Pss{
-		Kademlia:   k,
+		Kademlia: k,
+		KeyStore: loadKeyStore(),
+
 		privateKey: params.privateKey,
-		w:          whisper.New(&whisper.DefaultConfig),
 		quitC:      make(chan struct{}),
 
 		fwdPool:         make(map[string]*protocols.Peer),
@@ -177,11 +170,6 @@ func NewPss(k *network.Kademlia, params *PssParams) (*Pss, error) {
 		capstring:       cap.String(),
 		outbox:          make(chan *PssMsg, defaultOutboxCapacity),
 
-		pubKeyPool:                 make(map[string]map[Topic]*pssPeer),
-		symKeyPool:                 make(map[string]map[Topic]*pssPeer),
-		symKeyDecryptCache:         make([]*string, params.SymKeyCacheCapacity),
-		symKeyDecryptCacheCapacity: params.SymKeyCacheCapacity,
-
 		handlers:         make(map[Topic]map[*handler]bool),
 		topicHandlerCaps: make(map[Topic]*handlerCaps),
 
@@ -520,227 +508,6 @@ func (p *Pss) isSelfPossibleRecipient(msg *PssMsg, prox bool) bool {
 }
 
 /////////////////////////////////////////////////////////////////////
-// SECTION: Encryption
-/////////////////////////////////////////////////////////////////////
-
-// Links a peer ECDSA public key to a topic
-//
-// This is required for asymmetric message exchange
-// on the given topic
-//
-// The value in `address` will be used as a routing hint for the
-// public key / topic association
-func (p *Pss) SetPeerPublicKey(pubkey *ecdsa.PublicKey, topic Topic, address PssAddress) error {
-	if err := validateAddress(address); err != nil {
-		return err
-	}
-	pubkeybytes := crypto.FromECDSAPub(pubkey)
-	if len(pubkeybytes) == 0 {
-		return fmt.Errorf("invalid public key: %v", pubkey)
-	}
-	pubkeyid := common.ToHex(pubkeybytes)
-	psp := &pssPeer{
-		address: address,
-	}
-	p.pubKeyPoolMu.Lock()
-	if _, ok := p.pubKeyPool[pubkeyid]; !ok {
-		p.pubKeyPool[pubkeyid] = make(map[Topic]*pssPeer)
-	}
-	p.pubKeyPool[pubkeyid][topic] = psp
-	p.pubKeyPoolMu.Unlock()
-	log.Trace("added pubkey", "pubkeyid", pubkeyid, "topic", topic, "address", address)
-	return nil
-}
-
-// Automatically generate a new symkey for a topic and address hint
-func (p *Pss) GenerateSymmetricKey(topic Topic, address PssAddress, addToCache bool) (string, error) {
-	keyid, err := p.w.GenerateSymKey()
-	if err != nil {
-		return "", err
-	}
-	p.addSymmetricKeyToPool(keyid, topic, address, addToCache, false)
-	return keyid, nil
-}
-
-// Links a peer symmetric key (arbitrary byte sequence) to a topic
-//
-// This is required for symmetrically encrypted message exchange
-// on the given topic
-//
-// The key is stored in the whisper backend.
-//
-// If addtocache is set to true, the key will be added to the cache of keys
-// used to attempt symmetric decryption of incoming messages.
-//
-// Returns a string id that can be used to retrieve the key bytes
-// from the whisper backend (see pss.GetSymmetricKey())
-func (p *Pss) SetSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool) (string, error) {
-	if err := validateAddress(address); err != nil {
-		return "", err
-	}
-	return p.setSymmetricKey(key, topic, address, addtocache, true)
-}
-
-func (p *Pss) setSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool, protected bool) (string, error) {
-	keyid, err := p.w.AddSymKeyDirect(key)
-	if err != nil {
-		return "", err
-	}
-	p.addSymmetricKeyToPool(keyid, topic, address, addtocache, protected)
-	return keyid, nil
-}
-
-// adds a symmetric key to the pss key pool, and optionally adds the key
-// to the collection of keys used to attempt symmetric decryption of
-// incoming messages
-func (p *Pss) addSymmetricKeyToPool(keyid string, topic Topic, address PssAddress, addtocache bool, protected bool) {
-	psp := &pssPeer{
-		address:   address,
-		protected: protected,
-	}
-	p.symKeyPoolMu.Lock()
-	if _, ok := p.symKeyPool[keyid]; !ok {
-		p.symKeyPool[keyid] = make(map[Topic]*pssPeer)
-	}
-	p.symKeyPool[keyid][topic] = psp
-	p.symKeyPoolMu.Unlock()
-	if addtocache {
-		p.symKeyDecryptCacheCursor++
-		p.symKeyDecryptCache[p.symKeyDecryptCacheCursor%cap(p.symKeyDecryptCache)] = &keyid
-	}
-	key, _ := p.GetSymmetricKey(keyid)
-	log.Trace("added symkey", "symkeyid", keyid, "symkey", common.ToHex(key), "topic", topic, "address", address, "cache", addtocache)
-}
-
-// Returns a symmetric key byte seqyence stored in the whisper backend
-// by its unique id
-//
-// Passes on the error value from the whisper backend
-func (p *Pss) GetSymmetricKey(symkeyid string) ([]byte, error) {
-	symkey, err := p.w.GetSymKey(symkeyid)
-	if err != nil {
-		return nil, err
-	}
-	return symkey, nil
-}
-
-// Returns all recorded topic and address combination for a specific public key
-func (p *Pss) GetPublickeyPeers(keyid string) (topic []Topic, address []PssAddress, err error) {
-	p.pubKeyPoolMu.RLock()
-	defer p.pubKeyPoolMu.RUnlock()
-	for t, peer := range p.pubKeyPool[keyid] {
-		topic = append(topic, t)
-		address = append(address, peer.address)
-	}
-
-	return topic, address, nil
-}
-
-func (p *Pss) getPeerAddress(keyid string, topic Topic) (PssAddress, error) {
-	p.pubKeyPoolMu.RLock()
-	defer p.pubKeyPoolMu.RUnlock()
-	if peers, ok := p.pubKeyPool[keyid]; ok {
-		if t, ok := peers[topic]; ok {
-			return t.address, nil
-		}
-	}
-	return nil, fmt.Errorf("peer with pubkey %s, topic %x not found", keyid, topic)
-}
-
-// Attempt to decrypt, validate and unpack a
-// symmetrically encrypted message
-// If successful, returns the unpacked whisper ReceivedMessage struct
-// encapsulating the decrypted message, and the whisper backend id
-// of the symmetric key used to decrypt the message.
-// It fails if decryption of the message fails or if the message is corrupted
-func (p *Pss) processSym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
-	metrics.GetOrRegisterCounter("pss.process.sym", nil).Inc(1)
-
-	for i := p.symKeyDecryptCacheCursor; i > p.symKeyDecryptCacheCursor-cap(p.symKeyDecryptCache) && i > 0; i-- {
-		symkeyid := p.symKeyDecryptCache[i%cap(p.symKeyDecryptCache)]
-		symkey, err := p.w.GetSymKey(*symkeyid)
-		if err != nil {
-			continue
-		}
-		recvmsg, err := envelope.OpenSymmetric(symkey)
-		if err != nil {
-			continue
-		}
-		if !recvmsg.ValidateAndParse() {
-			return nil, "", nil, fmt.Errorf("symmetrically encrypted message has invalid signature or is corrupt")
-		}
-		p.symKeyPoolMu.Lock()
-		from := p.symKeyPool[*symkeyid][Topic(envelope.Topic)].address
-		p.symKeyPoolMu.Unlock()
-		p.symKeyDecryptCacheCursor++
-		p.symKeyDecryptCache[p.symKeyDecryptCacheCursor%cap(p.symKeyDecryptCache)] = symkeyid
-		return recvmsg, *symkeyid, from, nil
-	}
-	return nil, "", nil, fmt.Errorf("could not decrypt message")
-}
-
-// Attempt to decrypt, validate and unpack an
-// asymmetrically encrypted message
-// If successful, returns the unpacked whisper ReceivedMessage struct
-// encapsulating the decrypted message, and the byte representation of
-// the public key used to decrypt the message.
-// It fails if decryption of message fails, or if the message is corrupted
-func (p *Pss) processAsym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
-	metrics.GetOrRegisterCounter("pss.process.asym", nil).Inc(1)
-
-	recvmsg, err := envelope.OpenAsymmetric(p.privateKey)
-	if err != nil {
-		return nil, "", nil, fmt.Errorf("could not decrypt message: %s", err)
-	}
-	// check signature (if signed), strip padding
-	if !recvmsg.ValidateAndParse() {
-		return nil, "", nil, fmt.Errorf("invalid message")
-	}
-	pubkeyid := common.ToHex(crypto.FromECDSAPub(recvmsg.Src))
-	var from PssAddress
-	p.pubKeyPoolMu.Lock()
-	if p.pubKeyPool[pubkeyid][Topic(envelope.Topic)] != nil {
-		from = p.pubKeyPool[pubkeyid][Topic(envelope.Topic)].address
-	}
-	p.pubKeyPoolMu.Unlock()
-	return recvmsg, pubkeyid, from, nil
-}
-
-// Symkey garbage collection
-// a key is removed if:
-// - it is not marked as protected
-// - it is not in the incoming decryption cache
-func (p *Pss) cleanKeys() (count int) {
-	for keyid, peertopics := range p.symKeyPool {
-		var expiredtopics []Topic
-		for topic, psp := range peertopics {
-			if psp.protected {
-				continue
-			}
-
-			var match bool
-			for i := p.symKeyDecryptCacheCursor; i > p.symKeyDecryptCacheCursor-cap(p.symKeyDecryptCache) && i > 0; i-- {
-				cacheid := p.symKeyDecryptCache[i%cap(p.symKeyDecryptCache)]
-				if *cacheid == keyid {
-					match = true
-				}
-			}
-			if !match {
-				expiredtopics = append(expiredtopics, topic)
-			}
-		}
-		for _, topic := range expiredtopics {
-			p.symKeyPoolMu.Lock()
-			delete(p.symKeyPool[keyid], topic)
-			log.Trace("symkey cleanup deletion", "symkeyid", keyid, "topic", topic, "val", p.symKeyPool[keyid])
-			p.symKeyPoolMu.Unlock()
-			count++
-		}
-	}
-	return
-}
-
-/////////////////////////////////////////////////////////////////////
 // SECTION: Message sending
 /////////////////////////////////////////////////////////////////////
 
@@ -797,9 +564,7 @@ func (p *Pss) SendSym(symkeyid string, topic Topic, msg []byte) error {
 	if err != nil {
 		return fmt.Errorf("missing valid send symkey %s: %v", symkeyid, err)
 	}
-	p.symKeyPoolMu.Lock()
-	psp, ok := p.symKeyPool[symkeyid][topic]
-	p.symKeyPoolMu.Unlock()
+	psp, ok := p.getPeerSym(symkeyid, topic)
 	if !ok {
 		return fmt.Errorf("invalid topic '%s' for symkey '%s'", topic.String(), symkeyid)
 	}
@@ -813,9 +578,7 @@ func (p *Pss) SendAsym(pubkeyid string, topic Topic, msg []byte) error {
 	if _, err := crypto.UnmarshalPubkey(common.FromHex(pubkeyid)); err != nil {
 		return fmt.Errorf("Cannot unmarshal pubkey: %x", pubkeyid)
 	}
-	p.pubKeyPoolMu.Lock()
-	psp, ok := p.pubKeyPool[pubkeyid][topic]
-	p.pubKeyPoolMu.Unlock()
+	psp, ok := p.getPeerPub(pubkeyid, topic)
 	if !ok {
 		return fmt.Errorf("invalid topic '%s' for pubkey '%s'", topic.String(), pubkeyid)
 	}