wireguard-go/conn/sticky_linux.go
Jordan Whited 9e2f386022 conn, device, tun: implement vectorized I/O on Linux
Implement TCP offloading via TSO and GRO for the Linux tun.Device, which
is made possible by virtio extensions in the kernel's TUN driver.

Delete conn.LinuxSocketEndpoint in favor of a collapsed conn.StdNetBind.
conn.StdNetBind makes use of recvmmsg() and sendmmsg() on Linux. All
platforms now fall under conn.StdNetBind, except for Windows, which
remains in conn.WinRingBind, which still needs to be adjusted to handle
multiple packets.

Also refactor sticky sockets support to eventually be applicable on
platforms other than just Linux. However Linux remains the sole platform
that fully implements it for now.

Co-authored-by: James Tucker <james@tailscale.com>
Signed-off-by: James Tucker <james@tailscale.com>
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2023-03-10 14:52:17 +01:00

112 lines
2.6 KiB
Go

/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
*/
package conn
import (
"net/netip"
"unsafe"
"golang.org/x/sys/unix"
)
// getSrcFromControl parses the control for PKTINFO and if found updates ep with
// the source information found.
func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
ep.ClearSrc()
var (
hdr unix.Cmsghdr
data []byte
rem []byte = control
err error
)
for len(rem) > unix.SizeofCmsghdr {
hdr, data, rem, err = unix.ParseOneSocketControlMessage(control)
if err != nil {
return
}
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
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)
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 parses the control for PKTINFO and if found updates ep with
// the source information found.
func setSrcControl(control *[]byte, ep *StdNetEndpoint) {
*control = (*control)[:cap(*control)]
if len(*control) < int(unsafe.Sizeof(unix.Cmsghdr{})) {
*control = (*control)[:0]
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()
}
} else {
hdr.Level = unix.IPPROTO_IPV6
hdr.Type = unix.IPV6_PKTINFO
hdr.Len = unix.SizeofCmsghdr + 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)[:hdr.Len]
}
var srcControlSize = unix.CmsgLen(unix.SizeofInet6Pktinfo)