status-go/vendor/github.com/libp2p/go-libp2p-swarm/swarm.go

507 lines
12 KiB
Go

package swarm
import (
"context"
"errors"
"fmt"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/libp2p/go-libp2p-core/metrics"
"github.com/libp2p/go-libp2p-core/network"
"github.com/libp2p/go-libp2p-core/peer"
"github.com/libp2p/go-libp2p-core/peerstore"
"github.com/libp2p/go-libp2p-core/transport"
logging "github.com/ipfs/go-log"
"github.com/jbenet/goprocess"
goprocessctx "github.com/jbenet/goprocess/context"
filter "github.com/libp2p/go-maddr-filter"
mafilter "github.com/whyrusleeping/multiaddr-filter"
)
// DialTimeoutLocal is the maximum duration a Dial to local network address
// is allowed to take.
// This includes the time between dialing the raw network connection,
// protocol selection as well the handshake, if applicable.
var DialTimeoutLocal = 5 * time.Second
var log = logging.Logger("swarm2")
// ErrSwarmClosed is returned when one attempts to operate on a closed swarm.
var ErrSwarmClosed = errors.New("swarm closed")
// ErrAddrFiltered is returned when trying to register a connection to a
// filtered address. You shouldn't see this error unless some underlying
// transport is misbehaving.
var ErrAddrFiltered = errors.New("address filtered")
// Swarm is a connection muxer, allowing connections to other peers to
// be opened and closed, while still using the same Chan for all
// communication. The Chan sends/receives Messages, which note the
// destination or source Peer.
type Swarm struct {
// Close refcount. This allows us to fully wait for the swarm to be torn
// down before continuing.
refs sync.WaitGroup
local peer.ID
peers peerstore.Peerstore
conns struct {
sync.RWMutex
m map[peer.ID][]*Conn
}
listeners struct {
sync.RWMutex
m map[transport.Listener]struct{}
}
notifs struct {
sync.RWMutex
m map[network.Notifiee]struct{}
}
transports struct {
sync.RWMutex
m map[int]transport.Transport
}
// new connection and stream handlers
connh atomic.Value
streamh atomic.Value
// dialing helpers
dsync *DialSync
backf DialBackoff
limiter *dialLimiter
// filters for addresses that shouldnt be dialed (or accepted)
Filters *filter.Filters
proc goprocess.Process
ctx context.Context
bwc metrics.Reporter
}
// NewSwarm constructs a Swarm
func NewSwarm(ctx context.Context, local peer.ID, peers peerstore.Peerstore, bwc metrics.Reporter) *Swarm {
s := &Swarm{
local: local,
peers: peers,
bwc: bwc,
Filters: filter.NewFilters(),
}
s.conns.m = make(map[peer.ID][]*Conn)
s.listeners.m = make(map[transport.Listener]struct{})
s.transports.m = make(map[int]transport.Transport)
s.notifs.m = make(map[network.Notifiee]struct{})
s.dsync = NewDialSync(s.doDial)
s.limiter = newDialLimiter(s.dialAddr)
s.proc = goprocessctx.WithContextAndTeardown(ctx, s.teardown)
s.ctx = goprocessctx.OnClosingContext(s.proc)
return s
}
func (s *Swarm) teardown() error {
// Prevents new connections and/or listeners from being added to the swarm.
s.listeners.Lock()
listeners := s.listeners.m
s.listeners.m = nil
s.listeners.Unlock()
s.conns.Lock()
conns := s.conns.m
s.conns.m = nil
s.conns.Unlock()
// Lots of goroutines but we might as well do this in parallel. We want to shut down as fast as
// possible.
for l := range listeners {
go func(l transport.Listener) {
if err := l.Close(); err != nil {
log.Errorf("error when shutting down listener: %s", err)
}
}(l)
}
for _, cs := range conns {
for _, c := range cs {
go func(c *Conn) {
if err := c.Close(); err != nil {
log.Errorf("error when shutting down connection: %s", err)
}
}(c)
}
}
// Wait for everything to finish.
s.refs.Wait()
return nil
}
// AddAddrFilter adds a multiaddr filter to the set of filters the swarm will use to determine which
// addresses not to dial to.
func (s *Swarm) AddAddrFilter(f string) error {
m, err := mafilter.NewMask(f)
if err != nil {
return err
}
s.Filters.AddDialFilter(m)
return nil
}
// Process returns the Process of the swarm
func (s *Swarm) Process() goprocess.Process {
return s.proc
}
func (s *Swarm) addConn(tc transport.CapableConn, dir network.Direction) (*Conn, error) {
// The underlying transport (or the dialer) *should* filter it's own
// connections but we should double check anyways.
raddr := tc.RemoteMultiaddr()
if s.Filters.AddrBlocked(raddr) {
tc.Close()
return nil, ErrAddrFiltered
}
p := tc.RemotePeer()
// Add the public key.
if pk := tc.RemotePublicKey(); pk != nil {
s.peers.AddPubKey(p, pk)
}
// Clear any backoffs
s.backf.Clear(p)
// Finally, add the peer.
s.conns.Lock()
// Check if we're still online
if s.conns.m == nil {
s.conns.Unlock()
tc.Close()
return nil, ErrSwarmClosed
}
// Wrap and register the connection.
stat := network.Stat{Direction: dir}
c := &Conn{
conn: tc,
swarm: s,
stat: stat,
}
c.streams.m = make(map[*Stream]struct{})
s.conns.m[p] = append(s.conns.m[p], c)
// Add two swarm refs:
// * One will be decremented after the close notifications fire in Conn.doClose
// * The other will be decremented when Conn.start exits.
s.refs.Add(2)
// Take the notification lock before releasing the conns lock to block
// Disconnect notifications until after the Connect notifications done.
c.notifyLk.Lock()
s.conns.Unlock()
// We have a connection now. Cancel all other in-progress dials.
// This should be fast, no reason to wait till later.
s.dsync.CancelDial(p)
s.notifyAll(func(f network.Notifiee) {
f.Connected(s, c)
})
c.notifyLk.Unlock()
c.start()
// TODO: Get rid of this. We use it for identify but that happen much
// earlier (really, inside the transport and, if not then, during the
// notifications).
if h := s.ConnHandler(); h != nil {
go h(c)
}
return c, nil
}
// Peerstore returns this swarms internal Peerstore.
func (s *Swarm) Peerstore() peerstore.Peerstore {
return s.peers
}
// Context returns the context of the swarm
func (s *Swarm) Context() context.Context {
return s.ctx
}
// Close stops the Swarm.
func (s *Swarm) Close() error {
return s.proc.Close()
}
// TODO: We probably don't need the conn handlers.
// SetConnHandler assigns the handler for new connections.
// You will rarely use this. See SetStreamHandler
func (s *Swarm) SetConnHandler(handler network.ConnHandler) {
s.connh.Store(handler)
}
// ConnHandler gets the handler for new connections.
func (s *Swarm) ConnHandler() network.ConnHandler {
handler, _ := s.connh.Load().(network.ConnHandler)
return handler
}
// SetStreamHandler assigns the handler for new streams.
func (s *Swarm) SetStreamHandler(handler network.StreamHandler) {
s.streamh.Store(handler)
}
// StreamHandler gets the handler for new streams.
func (s *Swarm) StreamHandler() network.StreamHandler {
handler, _ := s.streamh.Load().(network.StreamHandler)
return handler
}
// NewStream creates a new stream on any available connection to peer, dialing
// if necessary.
func (s *Swarm) NewStream(ctx context.Context, p peer.ID) (network.Stream, error) {
log.Debugf("[%s] opening stream to peer [%s]", s.local, p)
// Algorithm:
// 1. Find the best connection, otherwise, dial.
// 2. Try opening a stream.
// 3. If the underlying connection is, in fact, closed, close the outer
// connection and try again. We do this in case we have a closed
// connection but don't notice it until we actually try to open a
// stream.
//
// Note: We only dial once.
//
// TODO: Try all connections even if we get an error opening a stream on
// a non-closed connection.
dials := 0
for {
c := s.bestConnToPeer(p)
if c == nil {
if nodial, _ := network.GetNoDial(ctx); nodial {
return nil, network.ErrNoConn
}
if dials >= DialAttempts {
return nil, errors.New("max dial attempts exceeded")
}
dials++
var err error
c, err = s.dialPeer(ctx, p)
if err != nil {
return nil, err
}
}
s, err := c.NewStream()
if err != nil {
if c.conn.IsClosed() {
continue
}
return nil, err
}
return s, nil
}
}
// ConnsToPeer returns all the live connections to peer.
func (s *Swarm) ConnsToPeer(p peer.ID) []network.Conn {
// TODO: Consider sorting the connection list best to worst. Currently,
// it's sorted oldest to newest.
s.conns.RLock()
defer s.conns.RUnlock()
conns := s.conns.m[p]
output := make([]network.Conn, len(conns))
for i, c := range conns {
output[i] = c
}
return output
}
// bestConnToPeer returns the best connection to peer.
func (s *Swarm) bestConnToPeer(p peer.ID) *Conn {
// Selects the best connection we have to the peer.
// TODO: Prefer some transports over others. Currently, we just select
// the newest non-closed connection with the most streams.
s.conns.RLock()
defer s.conns.RUnlock()
var best *Conn
bestLen := 0
for _, c := range s.conns.m[p] {
if c.conn.IsClosed() {
// We *will* garbage collect this soon anyways.
continue
}
c.streams.Lock()
cLen := len(c.streams.m)
c.streams.Unlock()
if cLen >= bestLen {
best = c
bestLen = cLen
}
}
return best
}
// Connectedness returns our "connectedness" state with the given peer.
//
// To check if we have an open connection, use `s.Connectedness(p) ==
// network.Connected`.
func (s *Swarm) Connectedness(p peer.ID) network.Connectedness {
if s.bestConnToPeer(p) != nil {
return network.Connected
}
return network.NotConnected
}
// Conns returns a slice of all connections.
func (s *Swarm) Conns() []network.Conn {
s.conns.RLock()
defer s.conns.RUnlock()
conns := make([]network.Conn, 0, len(s.conns.m))
for _, cs := range s.conns.m {
for _, c := range cs {
conns = append(conns, c)
}
}
return conns
}
// ClosePeer closes all connections to the given peer.
func (s *Swarm) ClosePeer(p peer.ID) error {
conns := s.ConnsToPeer(p)
switch len(conns) {
case 0:
return nil
case 1:
return conns[0].Close()
default:
errCh := make(chan error)
for _, c := range conns {
go func(c network.Conn) {
errCh <- c.Close()
}(c)
}
var errs []string
for _ = range conns {
err := <-errCh
if err != nil {
errs = append(errs, err.Error())
}
}
if len(errs) > 0 {
return fmt.Errorf("when disconnecting from peer %s: %s", p, strings.Join(errs, ", "))
}
return nil
}
}
// Peers returns a copy of the set of peers swarm is connected to.
func (s *Swarm) Peers() []peer.ID {
s.conns.RLock()
defer s.conns.RUnlock()
peers := make([]peer.ID, 0, len(s.conns.m))
for p := range s.conns.m {
peers = append(peers, p)
}
return peers
}
// LocalPeer returns the local peer swarm is associated to.
func (s *Swarm) LocalPeer() peer.ID {
return s.local
}
// Backoff returns the DialBackoff object for this swarm.
func (s *Swarm) Backoff() *DialBackoff {
return &s.backf
}
// notifyAll sends a signal to all Notifiees
func (s *Swarm) notifyAll(notify func(network.Notifiee)) {
var wg sync.WaitGroup
s.notifs.RLock()
wg.Add(len(s.notifs.m))
for f := range s.notifs.m {
go func(f network.Notifiee) {
defer wg.Done()
notify(f)
}(f)
}
wg.Wait()
s.notifs.RUnlock()
}
// Notify signs up Notifiee to receive signals when events happen
func (s *Swarm) Notify(f network.Notifiee) {
s.notifs.Lock()
s.notifs.m[f] = struct{}{}
s.notifs.Unlock()
}
// StopNotify unregisters Notifiee fromr receiving signals
func (s *Swarm) StopNotify(f network.Notifiee) {
s.notifs.Lock()
delete(s.notifs.m, f)
s.notifs.Unlock()
}
func (s *Swarm) removeConn(c *Conn) {
p := c.RemotePeer()
s.conns.Lock()
defer s.conns.Unlock()
cs := s.conns.m[p]
for i, ci := range cs {
if ci == c {
if len(cs) == 1 {
delete(s.conns.m, p)
} else {
// NOTE: We're intentionally preserving order.
// This way, connections to a peer are always
// sorted oldest to newest.
copy(cs[i:], cs[i+1:])
cs[len(cs)-1] = nil
s.conns.m[p] = cs[:len(cs)-1]
}
return
}
}
}
// String returns a string representation of Network.
func (s *Swarm) String() string {
return fmt.Sprintf("<Swarm %s>", s.LocalPeer())
}
// Swarm is a Network.
var _ network.Network = (*Swarm)(nil)
var _ transport.TransportNetwork = (*Swarm)(nil)