tailscale/net/socks5/tssocks/tssocks.go
Brad Fitzpatrick 3910c1edaf net/socks5/tssocks: add new package, move SOCKS5 glue out of tailscaled
Prep for #1970, #2264, #2268

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-06-28 11:34:50 -07:00

61 lines
1.6 KiB
Go

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tssocks is the glue between Tailscale and the net/socks5 package.
package tssocks
import (
"context"
"net"
"sync"
"inet.af/netaddr"
"tailscale.com/net/socks5"
"tailscale.com/net/tsaddr"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/wgengine"
"tailscale.com/wgengine/netstack"
)
// NewServer returns a new SOCKS5 server configured to dial out to
// Tailscale addresses.
//
// The returned server is not yet listening. The caller must call
// Serve with a listener.
//
// If ns is non-nil, it is used for dialing when needed.
func NewServer(logf logger.Logf, e wgengine.Engine, ns *netstack.Impl) *socks5.Server {
srv := &socks5.Server{
Logf: logf,
}
var (
mu sync.Mutex // guards the following field
dns netstack.DNSMap
)
e.AddNetworkMapCallback(func(nm *netmap.NetworkMap) {
mu.Lock()
defer mu.Unlock()
dns = netstack.DNSMapFromNetworkMap(nm)
})
useNetstackForIP := func(ip netaddr.IP) bool {
// TODO(bradfitz): this isn't exactly right.
// We should also support subnets when the
// prefs are configured as such.
return tsaddr.IsTailscaleIP(ip)
}
srv.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
ipp, err := dns.Resolve(ctx, addr)
if err != nil {
return nil, err
}
if ns != nil && useNetstackForIP(ipp.IP()) {
return ns.DialContextTCP(ctx, addr)
}
var d net.Dialer
return d.DialContext(ctx, network, ipp.String())
}
return srv
}