tailscale/wgengine/netstack/gro/gro_test.go
Jordan Whited df6014f1d7
net/tstun,wgengine{/netstack/gro}: refactor and re-enable gVisor GRO for Linux (#13172)
In 2f27319baf we disabled GRO due to a
data race around concurrent calls to tstun.Wrapper.Write(). This commit
refactors GRO to be thread-safe, and re-enables it on Linux.

This refactor now carries a GRO type across tstun and netstack APIs
with a lifetime that is scoped to a single tstun.Wrapper.Write() call.

In 25f0a3fc8f we used build tags to
prevent importation of gVisor's GRO package on iOS as at the time we
believed it was contributing to additional memory usage on that
platform. It wasn't, so this commit simplifies and removes those
build tags.

Updates tailscale/corp#22353
Updates tailscale/corp#22125
Updates #6816

Signed-off-by: Jordan Whited <jordan@tailscale.com>
2024-08-20 15:22:19 -07:00

113 lines
3.1 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package gro
import (
"bytes"
"net/netip"
"testing"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
"tailscale.com/net/packet"
)
func Test_RXChecksumOffload(t *testing.T) {
payloadLen := 100
tcpFields := &header.TCPFields{
SrcPort: 1,
DstPort: 1,
SeqNum: 1,
AckNum: 1,
DataOffset: 20,
Flags: header.TCPFlagAck | header.TCPFlagPsh,
WindowSize: 3000,
}
tcp4 := make([]byte, 20+20+payloadLen)
ipv4H := header.IPv4(tcp4)
ipv4H.Encode(&header.IPv4Fields{
SrcAddr: tcpip.AddrFromSlice(netip.MustParseAddr("192.0.2.1").AsSlice()),
DstAddr: tcpip.AddrFromSlice(netip.MustParseAddr("192.0.2.2").AsSlice()),
Protocol: uint8(header.TCPProtocolNumber),
TTL: 64,
TotalLength: uint16(len(tcp4)),
})
ipv4H.SetChecksum(^ipv4H.CalculateChecksum())
tcpH := header.TCP(tcp4[20:])
tcpH.Encode(tcpFields)
pseudoCsum := header.PseudoHeaderChecksum(header.TCPProtocolNumber, ipv4H.SourceAddress(), ipv4H.DestinationAddress(), uint16(20+payloadLen))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
tcp6ExtHeader := make([]byte, 40+8+20+payloadLen)
ipv6H := header.IPv6(tcp6ExtHeader)
ipv6H.Encode(&header.IPv6Fields{
SrcAddr: tcpip.AddrFromSlice(netip.MustParseAddr("2001:db8::1").AsSlice()),
DstAddr: tcpip.AddrFromSlice(netip.MustParseAddr("2001:db8::2").AsSlice()),
TransportProtocol: 60, // really next header; destination options ext header
HopLimit: 64,
PayloadLength: uint16(8 + 20 + payloadLen),
})
tcp6ExtHeader[40] = uint8(header.TCPProtocolNumber) // next header
tcp6ExtHeader[41] = 0 // length of ext header in 8-octet units, exclusive of first 8 octets.
// 42-47 options and padding
tcpH = header.TCP(tcp6ExtHeader[48:])
tcpH.Encode(tcpFields)
pseudoCsum = header.PseudoHeaderChecksum(header.TCPProtocolNumber, ipv6H.SourceAddress(), ipv6H.DestinationAddress(), uint16(20+payloadLen))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
tcp4InvalidCsum := make([]byte, len(tcp4))
copy(tcp4InvalidCsum, tcp4)
at := 20 + 16
tcp4InvalidCsum[at] = ^tcp4InvalidCsum[at]
tcp6ExtHeaderInvalidCsum := make([]byte, len(tcp6ExtHeader))
copy(tcp6ExtHeaderInvalidCsum, tcp6ExtHeader)
at = 40 + 8 + 16
tcp6ExtHeaderInvalidCsum[at] = ^tcp6ExtHeaderInvalidCsum[at]
tests := []struct {
name string
input []byte
wantPB bool
}{
{
"tcp4 packet valid csum",
tcp4,
true,
},
{
"tcp6 with ext header valid csum",
tcp6ExtHeader,
true,
},
{
"tcp4 packet invalid csum",
tcp4InvalidCsum,
false,
},
{
"tcp6 with ext header invalid csum",
tcp6ExtHeaderInvalidCsum,
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
p := &packet.Parsed{}
p.Decode(tt.input)
got := RXChecksumOffload(p)
if tt.wantPB != (got != nil) {
t.Fatalf("wantPB = %v != (got != nil): %v", tt.wantPB, got != nil)
}
if tt.wantPB {
gotBuf := got.ToBuffer()
if !bytes.Equal(tt.input, gotBuf.Flatten()) {
t.Fatal("output packet unequal to input")
}
}
})
}
}