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package p2p
import (
"context"
"errors"
"fmt"
"net"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/p2p/conn"
)
const (
// defaultProtocol is the default protocol used for NodeAddress when
// a protocol isn't explicitly given as a URL scheme.
defaultProtocol Protocol = MConnProtocol
)
// Protocol identifies a transport protocol.
type Protocol string
// Transport is a connection-oriented mechanism for exchanging data with a peer.
type Transport interface {
// Protocols returns the protocols supported by the transport. The Router
// uses this to pick a transport for an Endpoint.
Protocols() []Protocol
// Endpoints returns the local endpoints the transport is listening on, if any.
//
// How to listen is transport-dependent, e.g. MConnTransport uses Listen() while
// MemoryTransport starts listening via MemoryNetwork.CreateTransport().
Endpoints() []Endpoint
// Accept waits for the next inbound connection on a listening endpoint, blocking
// until either a connection is available or the transport is closed. On closure,
// io.EOF is returned and further Accept calls are futile.
Accept() (Connection, error)
// Dial creates an outbound connection to an endpoint.
Dial(context.Context, Endpoint) (Connection, error)
// Close stops accepting new connections, but does not close active connections.
Close() error
// Stringer is used to display the transport, e.g. in logs.
//
// Without this, the logger may use reflection to access and display
// internal fields. These can be written to concurrently, which can trigger
// the race detector or even cause a panic.
fmt.Stringer
}
// Connection represents an established connection between two endpoints.
//
// FIXME: This is a temporary interface for backwards-compatibility with the
// current MConnection-protocol, which is message-oriented. It should be
// migrated to a byte-oriented multi-stream interface instead, which would allow
// e.g. adopting QUIC and making message framing, traffic scheduling, and node
// handshakes a Router concern shared across all transports. However, this
// requires MConnection protocol changes or a shim. For details, see:
// https://github.com/tendermint/spec/pull/227
//
// FIXME: The interface is currently very broad in order to accommodate
// MConnection behavior that the legacy P2P stack relies on. It should be
// cleaned up when the legacy stack is removed.
type Connection interface {
// Handshake executes a node handshake with the remote peer. It must be
// called immediately after the connection is established, and returns the
// remote peer's node info and public key. The caller is responsible for
// validation.
//
// FIXME: The handshake should really be the Router's responsibility, but
// that requires the connection interface to be byte-oriented rather than
// message-oriented (see comment above).
Handshake(context.Context, NodeInfo, crypto.PrivKey) (NodeInfo, crypto.PubKey, error)
// ReceiveMessage returns the next message received on the connection,
// blocking until one is available. Returns io.EOF if closed.
ReceiveMessage() (ChannelID, []byte, error)
// SendMessage sends a message on the connection. Returns io.EOF if closed.
//
// FIXME: For compatibility with the legacy P2P stack, it returns an
// additional boolean false if the message timed out waiting to be accepted
// into the send buffer. This should be removed.
SendMessage(ChannelID, []byte) (bool, error)
// TrySendMessage is a non-blocking version of SendMessage that returns
// immediately if the message buffer is full. It returns true if the message
// was accepted.
//
// FIXME: This method is here for backwards-compatibility with the legacy
// P2P stack and should be removed.
TrySendMessage(ChannelID, []byte) (bool, error)
// LocalEndpoint returns the local endpoint for the connection.
LocalEndpoint() Endpoint
// RemoteEndpoint returns the remote endpoint for the connection.
RemoteEndpoint() Endpoint
// Close closes the connection.
Close() error
// FlushClose flushes all pending sends and then closes the connection.
//
// FIXME: This only exists for backwards-compatibility with the current
// MConnection implementation. There should really be a separate Flush()
// method, but there is no easy way to synchronously flush pending data with
// the current MConnection code.
FlushClose() error
// Status returns the current connection status.
// FIXME: Only here for compatibility with the current Peer code.
Status() conn.ConnectionStatus
// Stringer is used to display the connection, e.g. in logs.
//
// Without this, the logger may use reflection to access and display
// internal fields. These can be written to concurrently, which can trigger
// the race detector or even cause a panic.
fmt.Stringer
}
// Endpoint represents a transport connection endpoint, either local or remote.
//
// Endpoints are not necessarily networked (see e.g. MemoryTransport) but all
// networked endpoints must use IP as the underlying transport protocol to allow
// e.g. IP address filtering. Either IP or Path (or both) must be set.
type Endpoint struct {
// Protocol specifies the transport protocol.
Protocol Protocol
// IP is an IP address (v4 or v6) to connect to. If set, this defines the
// endpoint as a networked endpoint.
IP net.IP
// Port is a network port (either TCP or UDP). If 0, a default port may be
// used depending on the protocol.
Port uint16
// Path is an optional transport-specific path or identifier.
Path string
}
// NodeAddress converts the endpoint into a NodeAddress for the given node ID.
func (e Endpoint) NodeAddress(nodeID NodeID) NodeAddress {
address := NodeAddress{
NodeID: nodeID,
Protocol: e.Protocol,
Path: e.Path,
}
if len(e.IP) > 0 {
address.Hostname = e.IP.String()
address.Port = e.Port
}
return address
}
// String formats the endpoint as a URL string.
func (e Endpoint) String() string {
// If this is a non-networked endpoint with a valid node ID as a path,
// assume that path is a node ID (to handle opaque URLs of the form
// scheme:id).
if e.IP == nil {
if nodeID, err := NewNodeID(e.Path); err == nil {
return e.NodeAddress(nodeID).String()
}
}
return e.NodeAddress("").String()
}
// Validate validates the endpoint.
func (e Endpoint) Validate() error {
switch {
case e.Protocol == "":
return errors.New("endpoint has no protocol")
case len(e.IP) > 0 && e.IP.To16() == nil:
return fmt.Errorf("invalid IP address %v", e.IP)
case e.Port > 0 && len(e.IP) == 0:
return fmt.Errorf("endpoint has port %v but no IP", e.Port)
case len(e.IP) == 0 && e.Path == "":
return errors.New("endpoint has neither path nor IP")
default:
return nil
}
}