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conn, device: use UDP GSO and GRO on Linux

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StdNetBind probes for UDP GSO and GRO support at runtime. UDP GSO is
dependent on checksum offload support on the egress netdev. UDP GSO
will be disabled in the event sendmmsg() returns EIO, which is a strong
signal that the egress netdev does not support checksum offload.

The iperf3 results below demonstrate the effect of this commit between
two Linux computers with i5-12400 CPUs. There is roughly ~13us of round
trip latency between them.

The first result is from commit 052af4a without UDP GSO or GRO.

Starting Test: protocol: TCP, 1 streams, 131072 byte blocks
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-10.00  sec  9.85 GBytes  8.46 Gbits/sec  1139   3.01 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  9.85 GBytes  8.46 Gbits/sec  1139  sender
[  5]   0.00-10.04  sec  9.85 GBytes  8.42 Gbits/sec        receiver

The second result is with UDP GSO and GRO.

Starting Test: protocol: TCP, 1 streams, 131072 byte blocks
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-10.00  sec  12.3 GBytes  10.6 Gbits/sec  232   3.15 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  12.3 GBytes  10.6 Gbits/sec  232   sender
[  5]   0.00-10.04  sec  12.3 GBytes  10.6 Gbits/sec        receiver

Reviewed-by: Adrian Dewhurst <adrian@tailscale.com>
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jordan Whited
2023-10-02 13:53:07 -07:00
committed by Jason A. Donenfeld
parent 469159ecf7
commit 6a84778f2c
13 changed files with 672 additions and 146 deletions
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110
conn/sticky_linux.go
View File

@@ -1,110 +0,0 @@
//go:build linux && !android
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
*/
package conn
import (
"net/netip"
"unsafe"
"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) {
ep.ClearSrc()
var (
hdr unix.Cmsghdr
data []byte
rem []byte = control
err error
)
for len(rem) > unix.SizeofCmsghdr {
hdr, data, rem, err = unix.ParseOneSocketControlMessage(rem)
if err != nil {
return
}
if hdr.Level == unix.IPPROTO_IP &&
hdr.Type == unix.IP_PKTINFO {
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 {
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
}
}
}
// 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) {
if cap(*control) < len(ep.src) {
return
}
*control = (*control)[:0]
*control = append(*control, ep.src...)
}
var srcControlSize = unix.CmsgSpace(unix.SizeofInet6Pktinfo)
const StdNetSupportsStickySockets = true