mirror of https://github.com/fatedier/frp
86 lines
2.1 KiB
Go
86 lines
2.1 KiB
Go
// Copyright 2025 The frp Authors
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package vnet
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"net"
|
|
"os/exec"
|
|
|
|
"golang.zx2c4.com/wireguard/tun"
|
|
)
|
|
|
|
const (
|
|
defaultTunName = "utun"
|
|
defaultMTU = 1420
|
|
)
|
|
|
|
func openTun(_ context.Context, addr string) (tun.Device, error) {
|
|
dev, err := tun.CreateTUN(defaultTunName, defaultMTU)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
name, err := dev.Name()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
ip, ipNet, err := net.ParseCIDR(addr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Calculate a peer IP for the point-to-point tunnel
|
|
peerIP := generatePeerIP(ip)
|
|
|
|
// Configure the interface with proper point-to-point addressing
|
|
if err = exec.Command("ifconfig", name, "inet", ip.String(), peerIP.String(), "mtu", fmt.Sprint(defaultMTU), "up").Run(); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Add default route for the tunnel subnet
|
|
routes := []net.IPNet{*ipNet}
|
|
if err = addRoutes(name, routes); err != nil {
|
|
return nil, err
|
|
}
|
|
return dev, nil
|
|
}
|
|
|
|
// generatePeerIP creates a peer IP for the point-to-point tunnel
|
|
// by incrementing the last octet of the IP
|
|
func generatePeerIP(ip net.IP) net.IP {
|
|
// Make a copy to avoid modifying the original
|
|
peerIP := make(net.IP, len(ip))
|
|
copy(peerIP, ip)
|
|
|
|
// Increment the last octet
|
|
peerIP[len(peerIP)-1]++
|
|
|
|
return peerIP
|
|
}
|
|
|
|
// addRoutes configures system routes for the TUN interface
|
|
func addRoutes(ifName string, routes []net.IPNet) error {
|
|
for _, route := range routes {
|
|
routeStr := route.String()
|
|
if err := exec.Command("route", "add", "-net", routeStr, "-interface", ifName).Run(); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|