swarm_conn.go

package swarm

import (
	"fmt"

	ic "github.com/libp2p/go-libp2p-crypto"
	iconn "github.com/libp2p/go-libp2p-interface-conn"
	inet "github.com/libp2p/go-libp2p-net"
	peer "github.com/libp2p/go-libp2p-peer"
	ps "github.com/libp2p/go-peerstream"
	ma "github.com/multiformats/go-multiaddr"
)

// Conn is a simple wrapper around a ps.Conn that also exposes
// some of the methods from the underlying conn.Conn.
// There's **five** "layers" to each connection:
//  * 0. the net.Conn - underlying net.Conn (TCP/UDP/UTP/etc)
//  * 1. the manet.Conn - provides multiaddr friendly Conn
//  * 2. the conn.Conn - provides Peer friendly Conn (inc Secure channel)
//  * 3. the peerstream.Conn - provides peerstream / spdysptream happiness
//  * 4. the Conn - abstracts everyting out, exposing only key parts of underlying layers
// (I know, this is kinda crazy. it's more historical than a good design. though the
// layers do build up pieces of functionality. and they're all just io.RW :) )
type Conn ps.Conn

// ConnHandler is called when new conns are opened from remote peers.
// See peerstream.ConnHandler
type ConnHandler func(*Conn)

func (c *Conn) StreamConn() *ps.Conn {
	return (*ps.Conn)(c)
}

func (c *Conn) RawConn() iconn.Conn {
	// righly panic if these things aren't true. it is an expected
	// invariant that these Conns are all of the typewe expect:
	// 		ps.Conn wrapping a conn.Conn
	// if we get something else it is programmer error.
	return (*ps.Conn)(c).NetConn().(iconn.Conn)
}

func (c *Conn) String() string {
	return fmt.Sprintf("<SwarmConn %s>", c.RawConn())
}

// LocalMultiaddr is the Multiaddr on this side
func (c *Conn) LocalMultiaddr() ma.Multiaddr {
	return c.RawConn().LocalMultiaddr()
}

// LocalPeer is the Peer on our side of the connection
func (c *Conn) LocalPeer() peer.ID {
	return c.RawConn().LocalPeer()
}

// RemoteMultiaddr is the Multiaddr on the remote side
func (c *Conn) RemoteMultiaddr() ma.Multiaddr {
	return c.RawConn().RemoteMultiaddr()
}

// RemotePeer is the Peer on the remote side
func (c *Conn) RemotePeer() peer.ID {
	return c.RawConn().RemotePeer()
}

// LocalPrivateKey is the public key of the peer on this side
func (c *Conn) LocalPrivateKey() ic.PrivKey {
	return c.RawConn().LocalPrivateKey()
}

// RemotePublicKey is the public key of the peer on the remote side
func (c *Conn) RemotePublicKey() ic.PubKey {
	return c.RawConn().RemotePublicKey()
}

// NewSwarmStream returns a new Stream from this connection
func (c *Conn) NewSwarmStream() (*Stream, error) {
	s, err := c.StreamConn().NewStream()
	return (*Stream)(s), err
}

// NewStream returns a new Stream from this connection
func (c *Conn) NewStream() (inet.Stream, error) {
	s, err := c.NewSwarmStream()
	return inet.Stream(s), err
}

// Close closes the underlying stream connection
func (c *Conn) Close() error {
	return c.StreamConn().Close()
}

func (c *Conn) GetStreams() ([]inet.Stream, error) {
	ss := c.StreamConn().Streams()
	out := make([]inet.Stream, len(ss))

	for i, s := range ss {
		out[i] = (*Stream)(s)
	}
	return out, nil
}

func wrapConn(psc *ps.Conn) (*Conn, error) {
	// grab the underlying connection.
	if _, ok := psc.NetConn().(iconn.Conn); !ok {
		// this should never happen. if we see it ocurring it means that we added
		// a Listener to the ps.Swarm that is NOT one of our net/conn.Listener.
		return nil, fmt.Errorf("swarm connHandler: invalid conn (not a conn.Conn): %s", psc)
	}
	return (*Conn)(psc), nil
}

// wrapConns returns a *Conn for all these ps.Conns
func wrapConns(conns1 []*ps.Conn) []*Conn {
	conns2 := make([]*Conn, len(conns1))
	for i, c1 := range conns1 {
		if c2, err := wrapConn(c1); err == nil {
			conns2[i] = c2
		}
	}
	return conns2
}