2 GoVPN -- simple secure free software virtual private network daemon
3 Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 "golang.org/x/crypto/poly1305"
41 taps = make(map[string]*TAP)
44 // Return maximal acceptable TAP interface MTU. This is daemon's MTU
45 // minus nonce, MAC, packet size mark and Ethernet header sizes.
46 func TAPMaxMTU() int {
47 return MTU - poly1305.TagSize - NonceSize - PktSizeSize - EtherSize
50 func NewTAP(ifaceName string) (*TAP, error) {
51 maxIfacePktSize := TAPMaxMTU() + EtherSize
52 tapRaw, err := newTAPer(ifaceName)
59 buf0: make([]byte, maxIfacePktSize),
60 buf1: make([]byte, maxIfacePktSize),
61 Sink: make(chan []byte),
74 n, err = tap.dev.Read(buf)
76 panic("Reading TAP:" + err.Error())
84 func (t *TAP) Write(data []byte) (n int, err error) {
85 return t.dev.Write(data)
88 func TAPListen(ifaceName string) (*TAP, error) {
89 tap, exists := taps[ifaceName]
93 tap, err := NewTAP(ifaceName)