From 6a84778f2ca810f5fb5cb078e001494f08d9085f Mon Sep 17 00:00:00 2001 From: Jordan Whited Date: Mon, 2 Oct 2023 13:53:07 -0700 Subject: conn, device: use UDP GSO and GRO on Linux 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 Signed-off-by: Jordan Whited Signed-off-by: Jason A. Donenfeld --- conn/control_linux.go | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 conn/control_linux.go (limited to 'conn/control_linux.go') diff --git a/conn/control_linux.go b/conn/control_linux.go new file mode 100644 index 0000000..44a94e6 --- /dev/null +++ b/conn/control_linux.go @@ -0,0 +1,159 @@ +//go:build linux && !android + +/* SPDX-License-Identifier: MIT + * + * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved. + */ + +package conn + +import ( + "fmt" + "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...) +} + +const ( + sizeOfGSOData = 2 +) + +// getGSOSize parses control for UDP_GRO and if found returns its GSO size data. +func getGSOSize(control []byte) (int, error) { + var ( + hdr unix.Cmsghdr + data []byte + rem = control + err error + ) + + for len(rem) > unix.SizeofCmsghdr { + hdr, data, rem, err = unix.ParseOneSocketControlMessage(rem) + if err != nil { + return 0, fmt.Errorf("error parsing socket control message: %w", err) + } + if hdr.Level == unix.SOL_UDP && hdr.Type == unix.UDP_GRO && len(data) >= sizeOfGSOData { + var gso uint16 + copy(unsafe.Slice((*byte)(unsafe.Pointer(&gso)), sizeOfGSOData), data[:sizeOfGSOData]) + return int(gso), nil + } + } + return 0, nil +} + +// setGSOSize sets a UDP_SEGMENT in control based on gsoSize. It leaves existing +// data in control untouched. +func setGSOSize(control *[]byte, gsoSize uint16) { + existingLen := len(*control) + avail := cap(*control) - existingLen + space := unix.CmsgSpace(sizeOfGSOData) + if avail < space { + return + } + *control = (*control)[:cap(*control)] + gsoControl := (*control)[existingLen:] + hdr := (*unix.Cmsghdr)(unsafe.Pointer(&(gsoControl)[0])) + hdr.Level = unix.SOL_UDP + hdr.Type = unix.UDP_SEGMENT + hdr.SetLen(unix.CmsgLen(sizeOfGSOData)) + copy((gsoControl)[unix.SizeofCmsghdr:], unsafe.Slice((*byte)(unsafe.Pointer(&gsoSize)), sizeOfGSOData)) + *control = (*control)[:existingLen+space] +} + +// controlSize returns the recommended buffer size for pooling sticky and UDP +// offloading control data. +var controlSize = unix.CmsgSpace(unix.SizeofInet6Pktinfo) + unix.CmsgSpace(sizeOfGSOData) + +const StdNetSupportsStickySockets = true -- cgit v1.2.3