net

README

Network

The IPFS Network package handles all of the peer-to-peer networking. It connects to other hosts, it encrypts communications, it muxes messages between the network's client services and target hosts. It has multiple subcomponents:

• Conn - a connection to a single Peer
  • MultiConn - a set of connections to a single Peer
  • SecureConn - an encrypted (tls-like) connection
• Swarm - holds connections to Peers, multiplexes from/to each MultiConn
• Muxer - multiplexes between Services and Swarm. Handles Requet/Reply.
  • Service - connects between an outside client service and Network.
  • Handler - the client service part that handles requests

It looks a bit like this:


Documentation

Index

• Constants
• type Conn
• type ConnHandler
• type Connectedness
• type Dialer
• type Network
• type Notifiee
• type Stream
• type StreamHandler

Constants

const MessageSizeMax = 2 << 22 // 4MB

MessageSizeMax is a soft (recommended) maximum for network messages. One can write more, as the interface is a stream. But it is useful to bunch it up into multiple read/writes when the whole message is a single, large serialized object.

Types

type Conn

type Conn interface {
	conn.PeerConn

	// NewStream constructs a new Stream over this conn.
	NewStream() (Stream, error)
}

Conn is a connection to a remote peer. It multiplexes streams. Usually there is no need to use a Conn directly, but it may be useful to get information about the peer on the other side:

stream.Conn().RemotePeer()

type ConnHandler

type ConnHandler func(Conn)

ConnHandler is the type of function used to listen for connections opened by the remote side.

type Connectedness

type Connectedness int

Connectedness signals the capacity for a connection with a given node. It is used to signal to services and other peers whether a node is reachable.

const (
	// NotConnected means no connection to peer, and no extra information (default)
	NotConnected Connectedness = iota

	// Connected means has an open, live connection to peer
	Connected

	// CanConnect means recently connected to peer, terminated gracefully
	CanConnect

	// CannotConnect means recently attempted connecting but failed to connect.
	// (should signal "made effort, failed")
	CannotConnect
)

type Dialer

type Dialer interface {

	// Peerstore returns the internal peerstore
	// This is useful to tell the dialer about a new address for a peer.
	// Or use one of the public keys found out over the network.
	Peerstore() peer.Peerstore

	// LocalPeer returns the local peer associated with this network
	LocalPeer() peer.ID

	// DialPeer establishes a connection to a given peer
	DialPeer(context.Context, peer.ID) (Conn, error)

	// ClosePeer closes the connection to a given peer
	ClosePeer(peer.ID) error

	// Connectedness returns a state signaling connection capabilities
	Connectedness(peer.ID) Connectedness

	// Peers returns the peers connected
	Peers() []peer.ID

	// Conns returns the connections in this Netowrk
	Conns() []Conn

	// ConnsToPeer returns the connections in this Netowrk for given peer.
	ConnsToPeer(p peer.ID) []Conn

	// Notify/StopNotify register and unregister a notifiee for signals
	Notify(Notifiee)
	StopNotify(Notifiee)
}

Dialer represents a service that can dial out to peers (this is usually just a Network, but other services may not need the whole stack, and thus it becomes easier to mock)

type Network

type Network interface {
	Dialer
	io.Closer

	// SetStreamHandler sets the handler for new streams opened by the
	// remote side. This operation is threadsafe.
	SetStreamHandler(StreamHandler)

	// SetConnHandler sets the handler for new connections opened by the
	// remote side. This operation is threadsafe.
	SetConnHandler(ConnHandler)

	// NewStream returns a new stream to given peer p.
	// If there is no connection to p, attempts to create one.
	NewStream(peer.ID) (Stream, error)

	// Listen tells the network to start listening on given multiaddrs.
	Listen(...ma.Multiaddr) error

	// ListenAddresses returns a list of addresses at which this network listens.
	ListenAddresses() []ma.Multiaddr

	// InterfaceListenAddresses returns a list of addresses at which this network
	// listens. It expands "any interface" addresses (/ip4/0.0.0.0, /ip6/::) to
	// use the known local interfaces.
	InterfaceListenAddresses() ([]ma.Multiaddr, error)

	// Process returns the network's Process
	Process() goprocess.Process
}

Network is the interface used to connect to the outside world. It dials and listens for connections. it uses a Swarm to pool connnections (see swarm pkg, and peerstream.Swarm). Connections are encrypted with a TLS-like protocol.

type Notifiee

type Notifiee interface {
	Listen(Network, ma.Multiaddr)      // called when network starts listening on an addr
	ListenClose(Network, ma.Multiaddr) // called when network starts listening on an addr
	Connected(Network, Conn)           // called when a connection opened
	Disconnected(Network, Conn)        // called when a connection closed
	OpenedStream(Network, Stream)      // called when a stream opened
	ClosedStream(Network, Stream)      // called when a stream closed

}

Notifiee is an interface for an object wishing to receive notifications from a Network.

type Stream

type Stream interface {
	io.Reader
	io.Writer
	io.Closer

	// Conn returns the connection this stream is part of.
	Conn() Conn
}

Stream represents a bidirectional channel between two agents in the IPFS network. "agent" is as granular as desired, potentially being a "request -> reply" pair, or whole protocols. Streams are backed by SPDY streams underneath the hood.

type StreamHandler

type StreamHandler func(Stream)

StreamHandler is the type of function used to listen for streams opened by the remote side.