plugeth/swarm/pss/client/client.go
Felix Lange 30cd5c1854
all: new p2p node representation (#17643)
Package p2p/enode provides a generalized representation of p2p nodes
which can contain arbitrary information in key/value pairs. It is also
the new home for the node database. The "v4" identity scheme is also
moved here from p2p/enr to remove the dependency on Ethereum crypto from
that package.

Record signature handling is changed significantly. The identity scheme
registry is removed and acceptable schemes must be passed to any method
that needs identity. This means records must now be validated explicitly
after decoding.

The enode API is designed to make signature handling easy and safe: most
APIs around the codebase work with enode.Node, which is a wrapper around
a valid record. Going from enr.Record to enode.Node requires a valid
signature.

* p2p/discover: port to p2p/enode

This ports the discovery code to the new node representation in
p2p/enode. The wire protocol is unchanged, this can be considered a
refactoring change. The Kademlia table can now deal with nodes using an
arbitrary identity scheme. This requires a few incompatible API changes:

  - Table.Lookup is not available anymore. It used to take a public key
    as argument because v4 protocol requires one. Its replacement is
    LookupRandom.
  - Table.Resolve takes *enode.Node instead of NodeID. This is also for
    v4 protocol compatibility because nodes cannot be looked up by ID
    alone.
  - Types Node and NodeID are gone. Further commits in the series will be
    fixes all over the the codebase to deal with those removals.

* p2p: port to p2p/enode and discovery changes

This adapts package p2p to the changes in p2p/discover. All uses of
discover.Node and discover.NodeID are replaced by their equivalents from
p2p/enode.

New API is added to retrieve the enode.Node instance of a peer. The
behavior of Server.Self with discovery disabled is improved. It now
tries much harder to report a working IP address, falling back to
127.0.0.1 if no suitable address can be determined through other means.
These changes were needed for tests of other packages later in the
series.

* p2p/simulations, p2p/testing: port to p2p/enode

No surprises here, mostly replacements of discover.Node, discover.NodeID
with their new equivalents. The 'interesting' API changes are:

 - testing.ProtocolSession tracks complete nodes, not just their IDs.
 - adapters.NodeConfig has a new method to create a complete node.

These changes were needed to make swarm tests work.

Note that the NodeID change makes the code incompatible with old
simulation snapshots.

* whisper/whisperv5, whisper/whisperv6: port to p2p/enode

This port was easy because whisper uses []byte for node IDs and
URL strings in the API.

* eth: port to p2p/enode

Again, easy to port because eth uses strings for node IDs and doesn't
care about node information in any way.

* les: port to p2p/enode

Apart from replacing discover.NodeID with enode.ID, most changes are in
the server pool code. It now deals with complete nodes instead
of (Pubkey, IP, Port) triples. The database format is unchanged for now,
but we should probably change it to use the node database later.

* node: port to p2p/enode

This change simply replaces discover.Node and discover.NodeID with their
new equivalents.

* swarm/network: port to p2p/enode

Swarm has its own node address representation, BzzAddr, containing both
an overlay address (the hash of a secp256k1 public key) and an underlay
address (enode:// URL).

There are no changes to the BzzAddr format in this commit, but certain
operations such as creating a BzzAddr from a node ID are now impossible
because node IDs aren't public keys anymore.

Most swarm-related changes in the series remove uses of
NewAddrFromNodeID, replacing it with NewAddr which takes a complete node
as argument. ToOverlayAddr is removed because we can just use the node
ID directly.
2018-09-25 00:59:00 +02:00

353 lines
9.6 KiB
Go

// 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/>.
// +build !noclient,!noprotocol
package client
import (
"context"
"errors"
"fmt"
"sync"
"time"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/protocols"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/rpc"
"github.com/ethereum/go-ethereum/swarm/log"
"github.com/ethereum/go-ethereum/swarm/pss"
)
const (
handshakeRetryTimeout = 1000
handshakeRetryCount = 3
)
// The pss client provides devp2p emulation over pss RPC API,
// giving access to pss methods from a different process
type Client struct {
BaseAddrHex string
// peers
peerPool map[pss.Topic]map[string]*pssRPCRW
protos map[pss.Topic]*p2p.Protocol
// rpc connections
rpc *rpc.Client
subs []*rpc.ClientSubscription
// channels
topicsC chan []byte
quitC chan struct{}
poolMu sync.Mutex
}
// implements p2p.MsgReadWriter
type pssRPCRW struct {
*Client
topic string
msgC chan []byte
addr pss.PssAddress
pubKeyId string
lastSeen time.Time
closed bool
}
func (c *Client) newpssRPCRW(pubkeyid string, addr pss.PssAddress, topicobj pss.Topic) (*pssRPCRW, error) {
topic := topicobj.String()
err := c.rpc.Call(nil, "pss_setPeerPublicKey", pubkeyid, topic, hexutil.Encode(addr[:]))
if err != nil {
return nil, fmt.Errorf("setpeer %s %s: %v", topic, pubkeyid, err)
}
return &pssRPCRW{
Client: c,
topic: topic,
msgC: make(chan []byte),
addr: addr,
pubKeyId: pubkeyid,
}, nil
}
func (rw *pssRPCRW) ReadMsg() (p2p.Msg, error) {
msg := <-rw.msgC
log.Trace("pssrpcrw read", "msg", msg)
pmsg, err := pss.ToP2pMsg(msg)
if err != nil {
return p2p.Msg{}, err
}
return pmsg, nil
}
// If only one message slot left
// then new is requested through handshake
// if buffer is empty, handshake request blocks until return
// after which pointer is changed to first new key in buffer
// will fail if:
// - any api calls fail
// - handshake retries are exhausted without reply,
// - send fails
func (rw *pssRPCRW) WriteMsg(msg p2p.Msg) error {
log.Trace("got writemsg pssclient", "msg", msg)
if rw.closed {
return fmt.Errorf("connection closed")
}
rlpdata := make([]byte, msg.Size)
msg.Payload.Read(rlpdata)
pmsg, err := rlp.EncodeToBytes(pss.ProtocolMsg{
Code: msg.Code,
Size: msg.Size,
Payload: rlpdata,
})
if err != nil {
return err
}
// Get the keys we have
var symkeyids []string
err = rw.Client.rpc.Call(&symkeyids, "pss_getHandshakeKeys", rw.pubKeyId, rw.topic, false, true)
if err != nil {
return err
}
// Check the capacity of the first key
var symkeycap uint16
if len(symkeyids) > 0 {
err = rw.Client.rpc.Call(&symkeycap, "pss_getHandshakeKeyCapacity", symkeyids[0])
if err != nil {
return err
}
}
err = rw.Client.rpc.Call(nil, "pss_sendSym", symkeyids[0], rw.topic, hexutil.Encode(pmsg))
if err != nil {
return err
}
// If this is the last message it is valid for, initiate new handshake
if symkeycap == 1 {
var retries int
var sync bool
// if it's the only remaining key, make sure we don't continue until we have new ones for further writes
if len(symkeyids) == 1 {
sync = true
}
// initiate handshake
_, err := rw.handshake(retries, sync, false)
if err != nil {
log.Warn("failing", "err", err)
return err
}
}
return nil
}
// retry and synchronicity wrapper for handshake api call
// returns first new symkeyid upon successful execution
func (rw *pssRPCRW) handshake(retries int, sync bool, flush bool) (string, error) {
var symkeyids []string
var i int
// request new keys
// if the key buffer was depleted, make this as a blocking call and try several times before giving up
for i = 0; i < 1+retries; i++ {
log.Debug("handshake attempt pssrpcrw", "pubkeyid", rw.pubKeyId, "topic", rw.topic, "sync", sync)
err := rw.Client.rpc.Call(&symkeyids, "pss_handshake", rw.pubKeyId, rw.topic, sync, flush)
if err == nil {
var keyid string
if sync {
keyid = symkeyids[0]
}
return keyid, nil
}
if i-1+retries > 1 {
time.Sleep(time.Millisecond * handshakeRetryTimeout)
}
}
return "", fmt.Errorf("handshake failed after %d attempts", i)
}
// Custom constructor
//
// Provides direct access to the rpc object
func NewClient(rpcurl string) (*Client, error) {
rpcclient, err := rpc.Dial(rpcurl)
if err != nil {
return nil, err
}
client, err := NewClientWithRPC(rpcclient)
if err != nil {
return nil, err
}
return client, nil
}
// Main constructor
//
// The 'rpcclient' parameter allows passing a in-memory rpc client to act as the remote websocket RPC.
func NewClientWithRPC(rpcclient *rpc.Client) (*Client, error) {
client := newClient()
client.rpc = rpcclient
err := client.rpc.Call(&client.BaseAddrHex, "pss_baseAddr")
if err != nil {
return nil, fmt.Errorf("cannot get pss node baseaddress: %v", err)
}
return client, nil
}
func newClient() (client *Client) {
client = &Client{
quitC: make(chan struct{}),
peerPool: make(map[pss.Topic]map[string]*pssRPCRW),
protos: make(map[pss.Topic]*p2p.Protocol),
}
return
}
// Mounts a new devp2p protcool on the pss connection
//
// the protocol is aliased as a "pss topic"
// uses normal devp2p send and incoming message handler routines from the p2p/protocols package
//
// when an incoming message is received from a peer that is not yet known to the client,
// this peer object is instantiated, and the protocol is run on it.
func (c *Client) RunProtocol(ctx context.Context, proto *p2p.Protocol) error {
topicobj := pss.BytesToTopic([]byte(fmt.Sprintf("%s:%d", proto.Name, proto.Version)))
topichex := topicobj.String()
msgC := make(chan pss.APIMsg)
c.peerPool[topicobj] = make(map[string]*pssRPCRW)
sub, err := c.rpc.Subscribe(ctx, "pss", msgC, "receive", topichex)
if err != nil {
return fmt.Errorf("pss event subscription failed: %v", err)
}
c.subs = append(c.subs, sub)
err = c.rpc.Call(nil, "pss_addHandshake", topichex)
if err != nil {
return fmt.Errorf("pss handshake activation failed: %v", err)
}
// dispatch incoming messages
go func() {
for {
select {
case msg := <-msgC:
// we only allow sym msgs here
if msg.Asymmetric {
continue
}
// we get passed the symkeyid
// need the symkey itself to resolve to peer's pubkey
var pubkeyid string
err = c.rpc.Call(&pubkeyid, "pss_getHandshakePublicKey", msg.Key)
if err != nil || pubkeyid == "" {
log.Trace("proto err or no pubkey", "err", err, "symkeyid", msg.Key)
continue
}
// if we don't have the peer on this protocol already, create it
// this is more or less the same as AddPssPeer, less the handshake initiation
if c.peerPool[topicobj][pubkeyid] == nil {
var addrhex string
err := c.rpc.Call(&addrhex, "pss_getAddress", topichex, false, msg.Key)
if err != nil {
log.Trace(err.Error())
continue
}
addrbytes, err := hexutil.Decode(addrhex)
if err != nil {
log.Trace(err.Error())
break
}
addr := pss.PssAddress(addrbytes)
rw, err := c.newpssRPCRW(pubkeyid, addr, topicobj)
if err != nil {
break
}
c.peerPool[topicobj][pubkeyid] = rw
p := p2p.NewPeer(enode.ID{}, fmt.Sprintf("%v", addr), []p2p.Cap{})
go proto.Run(p, c.peerPool[topicobj][pubkeyid])
}
go func() {
c.peerPool[topicobj][pubkeyid].msgC <- msg.Msg
}()
case <-c.quitC:
return
}
}
}()
c.protos[topicobj] = proto
return nil
}
// Always call this to ensure that we exit cleanly
func (c *Client) Close() error {
for _, s := range c.subs {
s.Unsubscribe()
}
return nil
}
// Add a pss peer (public key) and run the protocol on it
//
// client.RunProtocol with matching topic must have been
// run prior to adding the peer, or this method will
// return an error.
//
// The key must exist in the key store of the pss node
// before the peer is added. The method will return an error
// if it is not.
func (c *Client) AddPssPeer(pubkeyid string, addr []byte, spec *protocols.Spec) error {
topic := pss.ProtocolTopic(spec)
if c.peerPool[topic] == nil {
return errors.New("addpeer on unset topic")
}
if c.peerPool[topic][pubkeyid] == nil {
rw, err := c.newpssRPCRW(pubkeyid, addr, topic)
if err != nil {
return err
}
_, err = rw.handshake(handshakeRetryCount, true, true)
if err != nil {
return err
}
c.poolMu.Lock()
c.peerPool[topic][pubkeyid] = rw
c.poolMu.Unlock()
p := p2p.NewPeer(enode.ID{}, fmt.Sprintf("%v", addr), []p2p.Cap{})
go c.protos[topic].Run(p, c.peerPool[topic][pubkeyid])
}
return nil
}
// Remove a pss peer
//
// TODO: underlying cleanup
func (c *Client) RemovePssPeer(pubkeyid string, spec *protocols.Spec) {
log.Debug("closing pss client peer", "pubkey", pubkeyid, "protoname", spec.Name, "protoversion", spec.Version)
c.poolMu.Lock()
defer c.poolMu.Unlock()
topic := pss.ProtocolTopic(spec)
c.peerPool[topic][pubkeyid].closed = true
delete(c.peerPool[topic], pubkeyid)
}