tailscale/wgengine/wgint/wgint.go
Brad Fitzpatrick 08b3f5f070 wgengine/wgint: add shady temporary package to get at wireguard internals
For #5451

Change-Id: I43482289e323ba9142a446d551ab7a94a467c43a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-08-29 10:03:51 -07:00

60 lines
1.7 KiB
Go

// Copyright (c) 2022 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 wgint provides somewhat shady access to wireguard-go
// internals that don't (yet) have public APIs.
package wgint
import (
"reflect"
"sync/atomic"
"unsafe"
"golang.zx2c4.com/wireguard/device"
)
var (
offHandshake = getPeerStatsOffset("lastHandshakeNano")
offRxBytes = getPeerStatsOffset("rxBytes")
offTxBytes = getPeerStatsOffset("txBytes")
)
func getPeerStatsOffset(name string) uintptr {
peerType := reflect.TypeOf(device.Peer{})
sf, ok := peerType.FieldByName("stats")
if !ok {
panic("no stats field in device.Peer")
}
if sf.Type.Kind() != reflect.Struct {
panic("stats field is not a struct")
}
base := sf.Offset
st := sf.Type
field, ok := st.FieldByName(name)
if !ok {
panic("no " + name + " field in device.Peer.stats")
}
if field.Type.Kind() != reflect.Int64 && field.Type.Kind() != reflect.Uint64 {
panic("unexpected kind of " + name + " field in device.Peer.stats")
}
return base + field.Offset
}
// PeerLastHandshakeNano returns the last handshake time in nanoseconds since the
// unix epoch.
func PeerLastHandshakeNano(peer *device.Peer) int64 {
return atomic.LoadInt64((*int64)(unsafe.Add(unsafe.Pointer(peer), offHandshake)))
}
// PeerRxBytes returns the number of bytes received from this peer.
func PeerRxBytes(peer *device.Peer) uint64 {
return atomic.LoadUint64((*uint64)(unsafe.Add(unsafe.Pointer(peer), offRxBytes)))
}
// PeerTxBytes returns the number of bytes sent to this peer.
func PeerTxBytes(peer *device.Peer) uint64 {
return atomic.LoadUint64((*uint64)(unsafe.Add(unsafe.Pointer(peer), offTxBytes)))
}