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// This file is part of gnunet-go, a GNUnet-implementation in Golang.
// Copyright (C) 2019-2022 Bernd Fix >Y<
//
// gnunet-go is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// gnunet-go is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: AGPL3.0-or-later
package transport
import (
"context"
"errors"
"gnunet/message"
"net"
)
// Error codes
var (
ErrConnectionNotOpened = errors.New("connection not opened")
ErrConnectionInterrupted = errors.New("connection interrupted")
)
//----------------------------------------------------------------------
// Connection is a net.Conn for GNUnet message exchange (send/receive)
type Connection struct {
conn net.Conn // associated connection
buf []byte // read/write buffer
}
// NewConnection creates a new connection from an existing net.Conn
// This is usually used by clients to connect to a service.
func NewConnection(ctx context.Context, conn net.Conn) *Connection {
return &Connection{
conn: conn,
buf: make([]byte, 65536),
}
}
// Close connection
func (s *Connection) Close() error {
if s.conn != nil {
rc := s.conn.Close()
s.conn = nil
return rc
}
return ErrConnectionNotOpened
}
// Send a GNUnet message over connection
func (s *Connection) Send(ctx context.Context, msg message.Message) error {
return WriteMessage(ctx, s.conn, msg)
}
// Receive GNUnet messages from socket.
func (s *Connection) Receive(ctx context.Context) (message.Message, error) {
return ReadMessage(ctx, s.conn, s.buf)
}
//----------------------------------------------------------------------
// ConnectionManager handles client connections on a net.Listener
type ConnectionManager struct {
listener net.Listener // reference to listener object
}
// NewConnectionManager creates a new net.Listener connection manager.
// Incoming connections from clients are dispatched to a handler channel.
func NewConnectionManager(ctx context.Context, listener net.Listener, hdlr chan *Connection) (cs *ConnectionManager, err error) {
// instantiate connection manager
cs = &ConnectionManager{
listener: listener,
}
// run watch dog for termination
go func() {
<-ctx.Done()
cs.listener.Close()
}()
// run go routine to handle channel requests from clients
go func() {
for {
conn, err := cs.listener.Accept()
if err != nil {
return
}
// handle connection
c := &Connection{
conn: conn,
buf: make([]byte, 65536),
}
hdlr <- c
}
}()
return cs, nil
}
// Close a connection manager (= stop the server)
func (s *ConnectionManager) Close() (err error) {
if s.listener != nil {
err = s.listener.Close()
s.listener = nil
}
return
}
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