psiphon-tunnel-core/psiphon/common/net.go

/*
 * Copyright (c) 2016, Psiphon Inc.
 * All rights reserved.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package common

import (
	"net"
	"sync"
)

// Conns is a synchronized list of Conns that is used to coordinate
// interrupting a set of goroutines establishing connections, or
// close a set of open connections, etc.
// Once the list is closed, no more items may be added to the
// list (unless it is reset).
type Conns struct {
	mutex    sync.Mutex
	isClosed bool
	conns    map[net.Conn]bool
}

func (conns *Conns) Reset() {
	conns.mutex.Lock()
	defer conns.mutex.Unlock()
	conns.isClosed = false
	conns.conns = make(map[net.Conn]bool)
}

func (conns *Conns) Add(conn net.Conn) bool {
	conns.mutex.Lock()
	defer conns.mutex.Unlock()
	if conns.isClosed {
		return false
	}
	if conns.conns == nil {
		conns.conns = make(map[net.Conn]bool)
	}
	conns.conns[conn] = true
	return true
}

func (conns *Conns) Remove(conn net.Conn) {
	conns.mutex.Lock()
	defer conns.mutex.Unlock()
	delete(conns.conns, conn)
}

func (conns *Conns) CloseAll() {
	conns.mutex.Lock()
	defer conns.mutex.Unlock()
	conns.isClosed = true
	for conn, _ := range conns.conns {
		conn.Close()
	}
	conns.conns = make(map[net.Conn]bool)
}

// IPAddressFromAddr is a helper which extracts an IP address
// from a net.Addr or returns "" if there is no IP address.
func IPAddressFromAddr(addr net.Addr) string {
	ipAddress := ""
	if addr != nil {
		host, _, err := net.SplitHostPort(addr.String())
		if err == nil {
			ipAddress = host
		}
	}
	return ipAddress
}