Hesham/wireguard-go
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conn: store IP_PKTINFO cmsg in StdNetendpoint src

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Replace the src storage inside StdNetEndpoint with a copy of the raw
control message buffer, to reduce allocation and perform less work on a
per-packet basis.

Signed-off-by: James Tucker <james@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
James Tucker 2023-04-18 22:29:55 -07:00 committed by Jason A. Donenfeld
parent b7cd547315
commit 25eb973e00
4 changed files with 128 additions and 98 deletions
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27
conn/bind_std.go
View File

@ -81,11 +81,10 @@ func NewStdNetBind() Bind {
type StdNetEndpoint struct {
// AddrPort is the endpoint destination.
netip.AddrPort
// src is the current sticky source address and interface index, if supported.
src struct {
netip.Addr
ifidx int32
}
// src is the current sticky source address and interface index, if
// supported. Typically this is a PKTINFO structure from/for control
// messages, see unix.PKTINFO for an example.
src []byte
}
var (
@ -104,21 +103,17 @@ func (*StdNetBind) ParseEndpoint(s string) (Endpoint, error) {
}
func (e *StdNetEndpoint) ClearSrc() {
e.src.ifidx = 0
e.src.Addr = netip.Addr{}
if e.src != nil {
// Truncate src, no need to reallocate.
e.src = e.src[:0]
}
}
func (e *StdNetEndpoint) DstIP() netip.Addr {
return e.AddrPort.Addr()
}
func (e *StdNetEndpoint) SrcIP() netip.Addr {
return e.src.Addr
}
func (e *StdNetEndpoint) SrcIfidx() int32 {
return e.src.ifidx
}
// See sticky_default,linux, etc for implementations of SrcIP and SrcIfidx.
func (e *StdNetEndpoint) DstToBytes() []byte {
b, _ := e.AddrPort.MarshalBinary()
@ -129,10 +124,6 @@ func (e *StdNetEndpoint) DstToString() string {
return e.AddrPort.String()
}
func (e *StdNetEndpoint) SrcToString() string {
return e.src.Addr.String()
}
func listenNet(network string, port int) (*net.UDPConn, int, error) {
conn, err := listenConfig().ListenPacket(context.Background(), network, ":"+strconv.Itoa(port))
if err != nil {

14
conn/sticky_default.go
View File

@ -7,6 +7,20 @@
package conn
import "net/netip"
func (e *StdNetEndpoint) SrcIP() netip.Addr {
return netip.Addr{}
}
func (e *StdNetEndpoint) SrcIfidx() int32 {
return 0
}
func (e *StdNetEndpoint) SrcToString() string {
return ""
}
// TODO: macOS, FreeBSD and other BSDs likely do support this feature set, but
// use alternatively named flags and need ports and require testing.

103
conn/sticky_linux.go
View File

@ -14,6 +14,37 @@ import (
"golang.org/x/sys/unix"
)
func (e *StdNetEndpoint) SrcIP() netip.Addr {
switch len(e.src) {
case unix.CmsgSpace(unix.SizeofInet4Pktinfo):
info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
return netip.AddrFrom4(info.Spec_dst)
case unix.CmsgSpace(unix.SizeofInet6Pktinfo):
info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
// TODO: set zone. in order to do so we need to check if the address is
// link local, and if it is perform a syscall to turn the ifindex into a
// zone string because netip uses string zones.
return netip.AddrFrom16(info.Addr)
}
return netip.Addr{}
}
func (e *StdNetEndpoint) SrcIfidx() int32 {
switch len(e.src) {
case unix.CmsgSpace(unix.SizeofInet4Pktinfo):
info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
return info.Ifindex
case unix.CmsgSpace(unix.SizeofInet6Pktinfo):
info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
return int32(info.Ifindex)
}
return 0
}
func (e *StdNetEndpoint) SrcToString() string {
return e.SrcIP().String()
}
// getSrcFromControl parses the control for PKTINFO and if found updates ep with
// the source information found.
func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
@ -35,81 +66,43 @@ func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
if hdr.Level == unix.IPPROTO_IP &&
hdr.Type == unix.IP_PKTINFO {
info := pktInfoFromBuf[unix.Inet4Pktinfo](data)
ep.src.Addr = netip.AddrFrom4(info.Spec_dst)
ep.src.ifidx = info.Ifindex
if ep.src == nil || cap(ep.src) < unix.CmsgSpace(unix.SizeofInet4Pktinfo) {
ep.src = make([]byte, 0, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
}
ep.src = ep.src[:unix.CmsgSpace(unix.SizeofInet4Pktinfo)]
hdrBuf := unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), unix.SizeofCmsghdr)
copy(ep.src, hdrBuf)
copy(ep.src[unix.CmsgLen(0):], data)
return
}
if hdr.Level == unix.IPPROTO_IPV6 &&
hdr.Type == unix.IPV6_PKTINFO {
info := pktInfoFromBuf[unix.Inet6Pktinfo](data)
ep.src.Addr = netip.AddrFrom16(info.Addr)
ep.src.ifidx = int32(info.Ifindex)
if ep.src == nil || cap(ep.src) < unix.CmsgSpace(unix.SizeofInet6Pktinfo) {
ep.src = make([]byte, 0, unix.CmsgSpace(unix.SizeofInet6Pktinfo))
}
ep.src = ep.src[:unix.CmsgSpace(unix.SizeofInet6Pktinfo)]
hdrBuf := unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), unix.SizeofCmsghdr)
copy(ep.src, hdrBuf)
copy(ep.src[unix.CmsgLen(0):], data)
return
}
}
}
// pktInfoFromBuf returns type T populated from the provided buf via copy(). It
// panics if buf is of insufficient size.
func pktInfoFromBuf[T unix.Inet4Pktinfo | unix.Inet6Pktinfo](buf []byte) (t T) {
size := int(unsafe.Sizeof(t))
if len(buf) < size {
panic("pktInfoFromBuf: buffer too small")
}
copy(unsafe.Slice((*byte)(unsafe.Pointer(&t)), size), buf)
return t
}
// setSrcControl sets an IP{V6}_PKTINFO in control based on the source address
// and source ifindex found in ep. control's len will be set to 0 in the event
// that ep is a default value.
func setSrcControl(control *[]byte, ep *StdNetEndpoint) {
*control = (*control)[:cap(*control)]
if len(*control) < int(unsafe.Sizeof(unix.Cmsghdr{})) {
*control = (*control)[:0]
if cap(*control) < len(ep.src) {
return
}
if ep.src.ifidx == 0 && !ep.SrcIP().IsValid() {
*control = (*control)[:0]
return
}
if len(*control) < srcControlSize {
*control = (*control)[:0]
return
}
hdr := (*unix.Cmsghdr)(unsafe.Pointer(&(*control)[0]))
if ep.SrcIP().Is4() {
hdr.Level = unix.IPPROTO_IP
hdr.Type = unix.IP_PKTINFO
hdr.SetLen(unix.CmsgLen(unix.SizeofInet4Pktinfo))
info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&(*control)[unix.SizeofCmsghdr]))
info.Ifindex = ep.src.ifidx
if ep.SrcIP().IsValid() {
info.Spec_dst = ep.SrcIP().As4()
}
*control = (*control)[:unix.CmsgSpace(unix.SizeofInet4Pktinfo)]
} else {
hdr.Level = unix.IPPROTO_IPV6
hdr.Type = unix.IPV6_PKTINFO
hdr.SetLen(unix.CmsgLen(unix.SizeofInet6Pktinfo))
info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&(*control)[unix.SizeofCmsghdr]))
info.Ifindex = uint32(ep.src.ifidx)
if ep.SrcIP().IsValid() {
info.Addr = ep.SrcIP().As16()
}
*control = (*control)[:unix.CmsgSpace(unix.SizeofInet6Pktinfo)]
}
*control = append(*control, ep.src...)
}
var srcControlSize = unix.CmsgSpace(unix.SizeofInet6Pktinfo)

80
conn/sticky_linux_test.go
View File

@ -18,13 +18,47 @@ import (
"golang.org/x/sys/unix"
)
func setSrc(ep *StdNetEndpoint, addr netip.Addr, ifidx int32) {
var buf []byte
if addr.Is4() {
buf = make([]byte, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
hdr := unix.Cmsghdr{
Level: unix.IPPROTO_IP,
Type: unix.IP_PKTINFO,
}
hdr.SetLen(unix.CmsgLen(unix.SizeofInet4Pktinfo))
copy(buf, unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), int(unsafe.Sizeof(hdr))))
info := unix.Inet4Pktinfo{
Ifindex: ifidx,
Spec_dst: addr.As4(),
}
copy(buf[unix.CmsgLen(0):], unsafe.Slice((*byte)(unsafe.Pointer(&info)), unix.SizeofInet4Pktinfo))
} else {
buf = make([]byte, unix.CmsgSpace(unix.SizeofInet6Pktinfo))
hdr := unix.Cmsghdr{
Level: unix.IPPROTO_IPV6,
Type: unix.IPV6_PKTINFO,
}
hdr.SetLen(unix.CmsgLen(unix.SizeofInet6Pktinfo))
copy(buf, unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), int(unsafe.Sizeof(hdr))))
info := unix.Inet6Pktinfo{
Ifindex: uint32(ifidx),
Addr: addr.As16(),
}
copy(buf[unix.CmsgLen(0):], unsafe.Slice((*byte)(unsafe.Pointer(&info)), unix.SizeofInet6Pktinfo))
}
ep.src = buf
}
func Test_setSrcControl(t *testing.T) {
t.Run("IPv4", func(t *testing.T) {
ep := &StdNetEndpoint{
AddrPort: netip.MustParseAddrPort("127.0.0.1:1234"),
}
ep.src.Addr = netip.MustParseAddr("127.0.0.1")
ep.src.ifidx = 5
setSrc(ep, netip.MustParseAddr("127.0.0.1"), 5)
control := make([]byte, srcControlSize)
@ -53,8 +87,7 @@ func Test_setSrcControl(t *testing.T) {
ep := &StdNetEndpoint{
AddrPort: netip.MustParseAddrPort("[::1]:1234"),
}
ep.src.Addr = netip.MustParseAddr("::1")
ep.src.ifidx = 5
setSrc(ep, netip.MustParseAddr("::1"), 5)
control := make([]byte, srcControlSize)
@ -80,7 +113,7 @@ func Test_setSrcControl(t *testing.T) {
})
t.Run("ClearOnNoSrc", func(t *testing.T) {
control := make([]byte, srcControlSize)
control := make([]byte, unix.CmsgLen(0))
hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
hdr.Level = 1
hdr.Type = 2
@ -96,7 +129,7 @@ func Test_setSrcControl(t *testing.T) {
func Test_getSrcFromControl(t *testing.T) {
t.Run("IPv4", func(t *testing.T) {
control := make([]byte, srcControlSize)
control := make([]byte, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
hdr.Level = unix.IPPROTO_IP
hdr.Type = unix.IP_PKTINFO
@ -108,15 +141,15 @@ func Test_getSrcFromControl(t *testing.T) {
ep := &StdNetEndpoint{}
getSrcFromControl(control, ep)
if ep.src.Addr != netip.MustParseAddr("127.0.0.1") {
t.Errorf("unexpected address: %v", ep.src.Addr)
if ep.SrcIP() != netip.MustParseAddr("127.0.0.1") {
t.Errorf("unexpected address: %v", ep.SrcIP())
}
if ep.src.ifidx != 5 {
t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
if ep.SrcIfidx() != 5 {
t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
}
})
t.Run("IPv6", func(t *testing.T) {
control := make([]byte, srcControlSize)
control := make([]byte, unix.CmsgSpace(unix.SizeofInet6Pktinfo))
hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
hdr.Level = unix.IPPROTO_IPV6
hdr.Type = unix.IPV6_PKTINFO
@ -131,22 +164,21 @@ func Test_getSrcFromControl(t *testing.T) {
if ep.SrcIP() != netip.MustParseAddr("::1") {
t.Errorf("unexpected address: %v", ep.SrcIP())
}
if ep.src.ifidx != 5 {
t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
if ep.SrcIfidx() != 5 {
t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
}
})
t.Run("ClearOnEmpty", func(t *testing.T) {
control := make([]byte, srcControlSize)
var control []byte
ep := &StdNetEndpoint{}
ep.src.Addr = netip.MustParseAddr("::1")
ep.src.ifidx = 5
setSrc(ep, netip.MustParseAddr("::1"), 5)
getSrcFromControl(control, ep)
if ep.SrcIP().IsValid() {
t.Errorf("unexpected address: %v", ep.src.Addr)
t.Errorf("unexpected address: %v", ep.SrcIP())
}
if ep.src.ifidx != 0 {
t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
if ep.SrcIfidx() != 0 {
t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
}
})
t.Run("Multiple", func(t *testing.T) {
@ -154,7 +186,7 @@ func Test_getSrcFromControl(t *testing.T) {
zeroHdr := (*unix.Cmsghdr)(unsafe.Pointer(&zeroControl[0]))
zeroHdr.SetLen(unix.CmsgLen(0))
control := make([]byte, srcControlSize)
control := make([]byte, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
hdr.Level = unix.IPPROTO_IP
hdr.Type = unix.IP_PKTINFO
@ -170,11 +202,11 @@ func Test_getSrcFromControl(t *testing.T) {
ep := &StdNetEndpoint{}
getSrcFromControl(combined, ep)
if ep.src.Addr != netip.MustParseAddr("127.0.0.1") {
t.Errorf("unexpected address: %v", ep.src.Addr)
if ep.SrcIP() != netip.MustParseAddr("127.0.0.1") {
t.Errorf("unexpected address: %v", ep.SrcIP())
}
if ep.src.ifidx != 5 {
t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
if ep.SrcIfidx() != 5 {
t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
}
})
}