// rawConnDial dials the underlying net.Conn + manet.Conns
func (d *Dialer) rawConnDial(ctx context.Context, raddr ma.Multiaddr, remote peer.ID) (manet.Conn, error) {
// before doing anything, check we're going to be able to dial.
// we may not support the given address.
if _, _, err := manet.DialArgs(raddr); err != nil {
return nil, err
}
if strings.HasPrefix(raddr.String(), "/ip4/0.0.0.0") {
log.Event(ctx, "connDialZeroAddr", lgbl.Dial("conn", d.LocalPeer, remote, nil, raddr))
return nil, fmt.Errorf("Attempted to connect to zero address: %s", raddr)
}
// get local addr to use.
laddr := pickLocalAddr(d.LocalAddrs, raddr)
logdial := lgbl.Dial("conn", d.LocalPeer, remote, laddr, raddr)
defer log.EventBegin(ctx, "connDialRawConn", logdial).Done()
// make a copy of the manet.Dialer, we may need to change its timeout.
madialer := d.Dialer
if laddr != nil && reuseportIsAvailable() {
// we're perhaps going to dial twice. half the timeout, so we can afford to.
// otherwise our context would expire right after the first dial.
madialer.Dialer.Timeout = (madialer.Dialer.Timeout / 2)
// dial using reuseport.Dialer, because we're probably reusing addrs.
// this is optimistic, as the reuseDial may fail to bind the port.
rpev := log.EventBegin(ctx, "connDialReusePort", logdial)
if nconn, retry, reuseErr := reuseDial(madialer.Dialer, laddr, raddr); reuseErr == nil {
// if it worked, wrap the raw net.Conn with our manet.Conn
logdial["reuseport"] = "success"
rpev.Done()
return manet.WrapNetConn(nconn)
} else if !retry {
// reuseDial is sure this is a legitimate dial failure, not a reuseport failure.
logdial["reuseport"] = "failure"
logdial["error"] = reuseErr
rpev.Done()
return nil, reuseErr
} else {
// this is a failure to reuse port. log it.
logdial["reuseport"] = "retry"
logdial["error"] = reuseErr
rpev.Done()
}
}
defer log.EventBegin(ctx, "connDialManet", logdial).Done()
return madialer.Dial(raddr)
}
// Dial connects to a peer.
//
// The idea is that the client of Swarm does not need to know what network
// the connection will happen over. Swarm can use whichever it choses.
// This allows us to use various transport protocols, do NAT traversal/relay,
// etc. to achive connection.
func (s *Swarm) Dial(ctx context.Context, p peer.ID) (*Conn, error) {
var logdial = lgbl.Dial("swarm", s.LocalPeer(), p, nil, nil)
if p == s.local {
log.Event(ctx, "swarmDialSelf", logdial)
return nil, ErrDialToSelf
}
return s.gatedDialAttempt(ctx, p)
}
// gatedDialAttempt is an attempt to dial a node. It is gated by the swarm's
// dial synchronization systems: dialsync and dialbackoff.
func (s *Swarm) gatedDialAttempt(ctx context.Context, p peer.ID) (*Conn, error) {
var logdial = lgbl.Dial("swarm", s.LocalPeer(), p, nil, nil)
defer log.EventBegin(ctx, "swarmDialAttemptSync", logdial).Done()
// check if we already have an open connection first
conn := s.bestConnectionToPeer(p)
if conn != nil {
return conn, nil
}
// check if there's an ongoing dial to this peer
if ok, wait := s.dsync.Lock(p); ok {
// ok, we have been charged to dial! let's do it.
// if it succeeds, dial will add the conn to the swarm itself.
defer log.EventBegin(ctx, "swarmDialAttemptStart", logdial).Done()
ctxT, cancel := context.WithTimeout(ctx, s.dialT)
conn, err := s.dial(ctxT, p)
cancel()
s.dsync.Unlock(p)
log.Debugf("dial end %s", conn)
if err != nil {
log.Event(ctx, "swarmDialBackoffAdd", logdial)
s.backf.AddBackoff(p) // let others know to backoff
// ok, we failed. try again. (if loop is done, our error is output)
return nil, fmt.Errorf("dial attempt failed: %s", err)
}
log.Event(ctx, "swarmDialBackoffClear", logdial)
s.backf.Clear(p) // okay, no longer need to backoff
return conn, nil
} else {
// we did not dial. we must wait for someone else to dial.
// check whether we should backoff first...
if s.backf.Backoff(p) {
log.Event(ctx, "swarmDialBackoff", logdial)
return nil, ErrDialBackoff
}
defer log.EventBegin(ctx, "swarmDialWait", logdial).Done()
select {
case <-wait: // wait for that other dial to finish.
// see if it worked, OR we got an incoming dial in the meantime...
conn := s.bestConnectionToPeer(p)
if conn != nil {
return conn, nil
}
return nil, ErrDialFailed
case <-ctx.Done(): // or we may have to bail...
return nil, ctx.Err()
}
}
}
// newConn constructs a new connection
func newSingleConn(ctx context.Context, local, remote peer.ID, maconn manet.Conn) (Conn, error) {
ml := lgbl.Dial("conn", local, remote, maconn.LocalMultiaddr(), maconn.RemoteMultiaddr())
conn := &singleConn{
local: local,
remote: remote,
maconn: maconn,
msgrw: msgio.NewReadWriter(maconn),
event: log.EventBegin(ctx, "connLifetime", ml),
}
log.Debugf("newSingleConn %p: %v to %v", conn, local, remote)
return conn, nil
}
// dial is the actual swarm's dial logic, gated by Dial.
func (s *Swarm) dial(ctx context.Context, p peer.ID) (*Conn, error) {
var logdial = lgbl.Dial("swarm", s.LocalPeer(), p, nil, nil)
if p == s.local {
log.Event(ctx, "swarmDialDoDialSelf", logdial)
return nil, ErrDialToSelf
}
defer log.EventBegin(ctx, "swarmDialDo", logdial).Done()
logdial["dial"] = "failure" // start off with failure. set to "success" at the end.
sk := s.peers.PrivKey(s.local)
logdial["encrypted"] = (sk != nil) // log wether this will be an encrypted dial or not.
if sk == nil {
// fine for sk to be nil, just log.
log.Debug("Dial not given PrivateKey, so WILL NOT SECURE conn.")
}
// get our own addrs. try dialing out from our listener addresses (reusing ports)
// Note that using our peerstore's addresses here is incorrect, as that would
// include observed addresses. TODO: make peerstore's address book smarter.
localAddrs := s.ListenAddresses()
if len(localAddrs) == 0 {
log.Debug("Dialing out with no local addresses.")
}
// get remote peer addrs
remoteAddrs := s.peers.Addrs(p)
// make sure we can use the addresses.
remoteAddrs = addrutil.FilterUsableAddrs(remoteAddrs)
// drop out any addrs that would just dial ourselves. use ListenAddresses
// as that is a more authoritative view than localAddrs.
ila, _ := s.InterfaceListenAddresses()
remoteAddrs = addrutil.Subtract(remoteAddrs, ila)
remoteAddrs = addrutil.Subtract(remoteAddrs, s.peers.Addrs(s.local))
log.Debugf("%s swarm dialing %s -- local:%s remote:%s", s.local, p, s.ListenAddresses(), remoteAddrs)
if len(remoteAddrs) == 0 {
err := errors.New("peer has no addresses")
logdial["error"] = err
return nil, err
}
remoteAddrs = s.filterAddrs(remoteAddrs)
if len(remoteAddrs) == 0 {
err := errors.New("all adresses for peer have been filtered out")
logdial["error"] = err
return nil, err
}
// open connection to peer
d := &conn.Dialer{
Dialer: manet.Dialer{
Dialer: net.Dialer{
Timeout: s.dialT,
},
},
LocalPeer: s.local,
LocalAddrs: localAddrs,
PrivateKey: sk,
Wrapper: func(c manet.Conn) manet.Conn {
return mconn.WrapConn(s.bwc, c)
},
}
// try to get a connection to any addr
connC, err := s.dialAddrs(ctx, d, p, remoteAddrs)
if err != nil {
logdial["error"] = err
return nil, err
}
logdial["netconn"] = lgbl.NetConn(connC)
// ok try to setup the new connection.
defer log.EventBegin(ctx, "swarmDialDoSetup", logdial, lgbl.NetConn(connC)).Done()
swarmC, err := dialConnSetup(ctx, s, connC)
if err != nil {
logdial["error"] = err
connC.Close() // close the connection. didn't work out :(
return nil, err
}
logdial["dial"] = "success"
return swarmC, nil
}
// Dial connects to a peer over a particular address
// Ensures raddr is part of peer.Addresses()
// Example: d.DialAddr(ctx, peer.Addresses()[0], peer)
func (d *Dialer) Dial(ctx context.Context, raddr ma.Multiaddr, remote peer.ID) (Conn, error) {
logdial := lgbl.Dial("conn", d.LocalPeer, remote, nil, raddr)
logdial["encrypted"] = (d.PrivateKey != nil) // log wether this will be an encrypted dial or not.
defer log.EventBegin(ctx, "connDial", logdial).Done()
var connOut Conn
var errOut error
done := make(chan struct{})
// do it async to ensure we respect don contexteone
go func() {
defer func() {
select {
case done <- struct{}{}:
case <-ctx.Done():
}
}()
maconn, err := d.rawConnDial(ctx, raddr, remote)
if err != nil {
errOut = err
return
}
if d.Wrapper != nil {
maconn = d.Wrapper(maconn)
}
c, err := newSingleConn(ctx, d.LocalPeer, remote, maconn)
if err != nil {
maconn.Close()
errOut = err
return
}
if d.PrivateKey == nil || EncryptConnections == false {
log.Warning("dialer %s dialing INSECURELY %s at %s!", d, remote, raddr)
connOut = c
return
}
c2, err := newSecureConn(ctx, d.PrivateKey, c)
if err != nil {
errOut = err
c.Close()
return
}
connOut = c2
}()
select {
case <-ctx.Done():
logdial["error"] = ctx.Err()
logdial["dial"] = "failure"
return nil, ctx.Err()
case <-done:
// whew, finished.
}
if errOut != nil {
logdial["error"] = errOut
logdial["dial"] = "failure"
return nil, errOut
}
logdial["dial"] = "success"
return connOut, nil
}