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/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
*/
package tun
import (
"net/netip"
"testing"
"golang.org/x/sys/unix"
"golang.zx2c4.com/wireguard/conn"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
const (
offset = virtioNetHdrLen
)
var (
ip4PortA = netip.MustParseAddrPort("192.0.2.1:1")
ip4PortB = netip.MustParseAddrPort("192.0.2.2:1")
ip4PortC = netip.MustParseAddrPort("192.0.2.3:1")
ip6PortA = netip.MustParseAddrPort("[2001:db8::1]:1")
ip6PortB = netip.MustParseAddrPort("[2001:db8::2]:1")
ip6PortC = netip.MustParseAddrPort("[2001:db8::3]:1")
)
func tcp4Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
totalLen := 40 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv4H := header.IPv4(b[offset:])
srcAs4 := srcIPPort.Addr().As4()
dstAs4 := dstIPPort.Addr().As4()
ipv4H.Encode(&header.IPv4Fields{
SrcAddr: tcpip.Address(srcAs4[:]),
DstAddr: tcpip.Address(dstAs4[:]),
Protocol: unix.IPPROTO_TCP,
TTL: 64,
TotalLength: uint16(totalLen),
})
tcpH := header.TCP(b[offset+20:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
ipv4H.SetChecksum(^ipv4H.CalculateChecksum())
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv4H.SourceAddress(), ipv4H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func tcp6Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
totalLen := 60 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv6H := header.IPv6(b[offset:])
srcAs16 := srcIPPort.Addr().As16()
dstAs16 := dstIPPort.Addr().As16()
ipv6H.Encode(&header.IPv6Fields{
SrcAddr: tcpip.Address(srcAs16[:]),
DstAddr: tcpip.Address(dstAs16[:]),
TransportProtocol: unix.IPPROTO_TCP,
HopLimit: 64,
PayloadLength: uint16(segmentSize + 20),
})
tcpH := header.TCP(b[offset+40:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv6H.SourceAddress(), ipv6H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func Test_handleVirtioRead(t *testing.T) {
tests := []struct {
name string
hdr virtioNetHdr
pktIn []byte
wantLens []int
wantErr bool
}{
{
"tcp4",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV4,
gsoSize: 100,
hdrLen: 40,
csumStart: 20,
csumOffset: 16,
},
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{140, 140},
false,
},
{
"tcp6",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV6,
gsoSize: 100,
hdrLen: 60,
csumStart: 40,
csumOffset: 16,
},
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{160, 160},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
out := make([][]byte, conn.IdealBatchSize)
sizes := make([]int, conn.IdealBatchSize)
for i := range out {
out[i] = make([]byte, 65535)
}
tt.hdr.encode(tt.pktIn)
n, err := handleVirtioRead(tt.pktIn, out, sizes, offset)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if n != len(tt.wantLens) {
t.Fatalf("got %d packets, wanted %d", n, len(tt.wantLens))
}
for i := range tt.wantLens {
if tt.wantLens[i] != sizes[i] {
t.Fatalf("wantLens[%d]: %d != outSizes: %d", i, tt.wantLens[i], sizes[i])
}
}
})
}
}
func flipTCP4Checksum(b []byte) []byte {
at := virtioNetHdrLen + 20 + 16 // 20 byte ipv4 header; tcp csum offset is 16
b[at] ^= 0xFF
b[at+1] ^= 0xFF
return b
}
func Fuzz_handleGRO(f *testing.F) {
pkt0 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)
pkt1 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101)
pkt2 := tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201)
pkt3 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1)
pkt4 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101)
pkt5 := tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201)
f.Add(pkt0, pkt1, pkt2, pkt3, pkt4, pkt5, offset)
f.Fuzz(func(t *testing.T, pkt0, pkt1, pkt2, pkt3, pkt4, pkt5 []byte, offset int) {
pkts := [][]byte{pkt0, pkt1, pkt2, pkt3, pkt4, pkt5}
toWrite := make([]int, 0, len(pkts))
handleGRO(pkts, offset, newTCPGROTable(), newTCPGROTable(), &toWrite)
if len(toWrite) > len(pkts) {
t.Errorf("len(toWrite): %d > len(pkts): %d", len(toWrite), len(pkts))
}
seenWriteI := make(map[int]bool)
for _, writeI := range toWrite {
if writeI < 0 || writeI > len(pkts)-1 {
t.Errorf("toWrite value (%d) outside bounds of len(pkts): %d", writeI, len(pkts))
}
if seenWriteI[writeI] {
t.Errorf("duplicate toWrite value: %d", writeI)
}
seenWriteI[writeI] = true
}
})
}
func Test_handleGRO(t *testing.T) {
tests := []struct {
name string
pktsIn [][]byte
wantToWrite []int
wantLens []int
wantErr bool
}{
{
"multiple flows",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201), // v4 flow 2
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201), // v6 flow 2
},
[]int{0, 2, 3, 5},
[]int{240, 140, 260, 160},
false,
},
{
"PSH interleaved",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 301), // v4 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 201), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 301), // v6 flow 1
},
[]int{0, 2, 4, 6},
[]int{240, 240, 260, 260},
false,
},
{
"coalesceItemInvalidCSum",
[][]byte{
flipTCP4Checksum(tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
},
[]int{0, 1},
[]int{140, 240},
false,
},
{
"out of order",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
},
[]int{0},
[]int{340},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
toWrite := make([]int, 0, len(tt.pktsIn))
err := handleGRO(tt.pktsIn, offset, newTCPGROTable(), newTCPGROTable(), &toWrite)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if len(toWrite) != len(tt.wantToWrite) {
t.Fatalf("got %d packets, wanted %d", len(toWrite), len(tt.wantToWrite))
}
for i, pktI := range tt.wantToWrite {
if tt.wantToWrite[i] != toWrite[i] {
t.Fatalf("wantToWrite[%d]: %d != toWrite: %d", i, tt.wantToWrite[i], toWrite[i])
}
if tt.wantLens[i] != len(tt.pktsIn[pktI][offset:]) {
t.Errorf("wanted len %d packet at %d, got: %d", tt.wantLens[i], i, len(tt.pktsIn[pktI][offset:]))
}
}
})
}
}
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