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tailscale/net/packet/packet_test.go

723 lines
20 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package packet
import (
"bytes"
"encoding/binary"
"encoding/hex"
"net/netip"
"reflect"
"strings"
"testing"
"unicode"
"tailscale.com/tstest"
"tailscale.com/types/ipproto"
"tailscale.com/util/must"
)
const (
Unknown = ipproto.Unknown
TCP = ipproto.TCP
UDP = ipproto.UDP
SCTP = ipproto.SCTP
IGMP = ipproto.IGMP
ICMPv4 = ipproto.ICMPv4
ICMPv6 = ipproto.ICMPv6
TSMP = ipproto.TSMP
Fragment = ipproto.Fragment
)
func fullHeaderChecksumV4(b []byte) uint16 {
s := uint32(0)
for i := 0; i < len(b); i += 2 {
if i == 10 {
// Skip checksum field.
continue
}
s += uint32(binary.BigEndian.Uint16(b[i : i+2]))
}
for s>>16 > 0 {
s = s&0xFFFF + s>>16
}
return ^uint16(s)
}
func TestHeaderChecksums(t *testing.T) {
// This is not a good enough test, because it doesn't
// check the various packet types or the many edge cases
// of the checksum algorithm. But it's a start.
tests := []struct {
name string
packet []byte
}{
{
name: "ICMPv4",
packet: []byte{
0x45, 0x00, 0x00, 0x54, 0xb7, 0x96, 0x40, 0x00, 0x40, 0x01, 0x7a, 0x06, 0x64, 0x7f, 0x3f, 0x4c, 0x64, 0x40, 0x01, 0x01, 0x08, 0x00, 0x47, 0x1a, 0x00, 0x11, 0x01, 0xac, 0xcc, 0xf5, 0x95, 0x63, 0x00, 0x00, 0x00, 0x00, 0x8d, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
},
},
{
name: "TLS",
packet: []byte{
0x45, 0x00, 0x00, 0x3c, 0x54, 0x29, 0x40, 0x00, 0x40, 0x06, 0xb1, 0xac, 0x64, 0x42, 0xd4, 0x33, 0x64, 0x61, 0x98, 0x0f, 0xb1, 0x94, 0x01, 0xbb, 0x0a, 0x51, 0xce, 0x7c, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x02, 0xfb, 0xe0, 0x38, 0xf6, 0x00, 0x00, 0x02, 0x04, 0x04, 0xd8, 0x04, 0x02, 0x08, 0x0a, 0x86, 0x2b, 0xcc, 0xd5, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x03, 0x07,
},
},
{
name: "DNS",
packet: []byte{
0x45, 0x00, 0x00, 0x74, 0xe2, 0x85, 0x00, 0x00, 0x40, 0x11, 0x96, 0xb5, 0x64, 0x64, 0x64, 0x64, 0x64, 0x42, 0xd4, 0x33, 0x00, 0x35, 0xec, 0x55, 0x00, 0x60, 0xd9, 0x19, 0xed, 0xfd, 0x81, 0x80, 0x00, 0x01, 0x00, 0x02, 0x00, 0x00, 0x00, 0x01, 0x08, 0x63, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x73, 0x34, 0x06, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x03, 0x63, 0x6f, 0x6d, 0x00, 0x00, 0x01, 0x00, 0x01, 0xc0, 0x0c, 0x00, 0x05, 0x00, 0x01, 0x00, 0x00, 0x01, 0x1e, 0x00, 0x0c, 0x07, 0x63, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x73, 0x01, 0x6c, 0xc0, 0x15, 0xc0, 0x31, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x01, 0x1e, 0x00, 0x04, 0x8e, 0xfa, 0xbd, 0xce, 0x00, 0x00, 0x29, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
},
},
}
var p Parsed
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
p.Decode(tt.packet)
t.Log(p.String())
p.UpdateSrcAddr(netip.MustParseAddr("100.64.0.1"))
got := binary.BigEndian.Uint16(tt.packet[10:12])
want := fullHeaderChecksumV4(tt.packet[:20])
if got != want {
t.Fatalf("got %x want %x", got, want)
}
p.UpdateDstAddr(netip.MustParseAddr("100.64.0.2"))
got = binary.BigEndian.Uint16(tt.packet[10:12])
want = fullHeaderChecksumV4(tt.packet[:20])
if got != want {
t.Fatalf("got %x want %x", got, want)
}
})
}
}
func mustIPPort(s string) netip.AddrPort {
ipp, err := netip.ParseAddrPort(s)
if err != nil {
panic(err)
}
return ipp
}
var icmp4RequestBuffer = []byte{
// IP header up to checksum
0x45, 0x00, 0x00, 0x27, 0xde, 0xad, 0x00, 0x00, 0x40, 0x01, 0x8c, 0x15,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
// ICMP header
0x08, 0x00, 0x7d, 0x22,
// "request_payload"
0x72, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var icmp4RequestDecode = Parsed{
b: icmp4RequestBuffer,
subofs: 20,
dataofs: 24,
length: len(icmp4RequestBuffer),
IPVersion: 4,
IPProto: ICMPv4,
Src: mustIPPort("1.2.3.4:0"),
Dst: mustIPPort("5.6.7.8:0"),
}
var icmp4ReplyBuffer = []byte{
0x45, 0x00, 0x00, 0x25, 0x21, 0x52, 0x00, 0x00, 0x40, 0x01, 0x49, 0x73,
// source IP
0x05, 0x06, 0x07, 0x08,
// destination IP
0x01, 0x02, 0x03, 0x04,
// ICMP header
0x00, 0x00, 0xe6, 0x9e,
// "reply_payload"
0x72, 0x65, 0x70, 0x6c, 0x79, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var icmp4ReplyDecode = Parsed{
b: icmp4ReplyBuffer,
subofs: 20,
dataofs: 24,
length: len(icmp4ReplyBuffer),
IPVersion: 4,
IPProto: ICMPv4,
Src: mustIPPort("1.2.3.4:0"),
Dst: mustIPPort("5.6.7.8:0"),
}
// ICMPv6 Router Solicitation
var icmp6PacketBuffer = []byte{
0x60, 0x00, 0x00, 0x00, 0x00, 0x08, 0x3a, 0xff,
0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xfb, 0x57, 0x1d, 0xea, 0x9c, 0x39, 0x8f, 0xb7,
0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02,
0x85, 0x00, 0x38, 0x04, 0x00, 0x00, 0x00, 0x00,
}
var icmp6PacketDecode = Parsed{
b: icmp6PacketBuffer,
subofs: 40,
dataofs: 44,
length: len(icmp6PacketBuffer),
IPVersion: 6,
IPProto: ICMPv6,
Src: mustIPPort("[fe80::fb57:1dea:9c39:8fb7]:0"),
Dst: mustIPPort("[ff02::2]:0"),
}
// This is a malformed IPv4 packet.
// Namely, the string "tcp_payload" follows the first byte of the IPv4 header.
var unknownPacketBuffer = []byte{
0x45, 0x74, 0x63, 0x70, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var unknownPacketDecode = Parsed{
b: unknownPacketBuffer,
IPVersion: 0,
IPProto: Unknown,
}
var tcp4PacketBuffer = []byte{
// IP header up to checksum
0x45, 0x00, 0x00, 0x37, 0xde, 0xad, 0x00, 0x00, 0x40, 0x06, 0x49, 0x5f,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
// TCP header with SYN, ACK set
0x00, 0x7b, 0x02, 0x37, 0x00, 0x00, 0x12, 0x34, 0x00, 0x00, 0x00, 0x00,
0x50, 0x12, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
// "request_payload"
0x72, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var tcp4PacketDecode = Parsed{
b: tcp4PacketBuffer,
subofs: 20,
dataofs: 40,
length: len(tcp4PacketBuffer),
IPVersion: 4,
IPProto: TCP,
Src: mustIPPort("1.2.3.4:123"),
Dst: mustIPPort("5.6.7.8:567"),
TCPFlags: TCPSynAck,
}
var tcp6RequestBuffer = []byte{
// IPv6 header up to hop limit
0x60, 0x06, 0xef, 0xcc, 0x00, 0x28, 0x06, 0x40,
// Src addr
0x20, 0x01, 0x05, 0x59, 0xbc, 0x13, 0x54, 0x00, 0x17, 0x49, 0x46, 0x28, 0x39, 0x34, 0x0e, 0x1b,
// Dst addr
0x26, 0x07, 0xf8, 0xb0, 0x40, 0x0a, 0x08, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x0e,
// TCP SYN segment, no payload
0xa4, 0x60, 0x00, 0x50, 0xf3, 0x82, 0xa1, 0x25, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x02, 0xfd, 0x20,
0xb1, 0xc6, 0x00, 0x00, 0x02, 0x04, 0x05, 0xa0, 0x04, 0x02, 0x08, 0x0a, 0xca, 0x76, 0xa6, 0x8e,
0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x03, 0x07,
}
var tcp6RequestDecode = Parsed{
b: tcp6RequestBuffer,
subofs: 40,
dataofs: len(tcp6RequestBuffer),
length: len(tcp6RequestBuffer),
IPVersion: 6,
IPProto: TCP,
Src: mustIPPort("[2001:559:bc13:5400:1749:4628:3934:e1b]:42080"),
Dst: mustIPPort("[2607:f8b0:400a:809::200e]:80"),
TCPFlags: TCPSyn,
}
var udp4RequestBuffer = []byte{
// IP header up to checksum
0x45, 0x00, 0x00, 0x2b, 0xde, 0xad, 0x00, 0x00, 0x40, 0x11, 0x8c, 0x01,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
// UDP header
0x00, 0x7b, 0x02, 0x37, 0x00, 0x17, 0x72, 0x1d,
// "request_payload"
0x72, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var udp4RequestDecode = Parsed{
b: udp4RequestBuffer,
subofs: 20,
dataofs: 28,
length: len(udp4RequestBuffer),
IPVersion: 4,
IPProto: UDP,
Src: mustIPPort("1.2.3.4:123"),
Dst: mustIPPort("5.6.7.8:567"),
}
var invalid4RequestBuffer = []byte{
// IP header up to checksum. IHL field points beyond end of packet.
0x4a, 0x00, 0x00, 0x14, 0xde, 0xad, 0x00, 0x00, 0x40, 0x11, 0x8c, 0x01,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
}
// Regression check for the IHL field pointing beyond the end of the
// packet.
var invalid4RequestDecode = Parsed{
b: invalid4RequestBuffer,
subofs: 40,
length: len(invalid4RequestBuffer),
IPVersion: 4,
IPProto: Unknown,
Src: mustIPPort("1.2.3.4:0"),
Dst: mustIPPort("5.6.7.8:0"),
}
var udp6RequestBuffer = []byte{
// IPv6 header up to hop limit
0x60, 0x0e, 0xc9, 0x67, 0x00, 0x29, 0x11, 0x40,
// Src addr
0x20, 0x01, 0x05, 0x59, 0xbc, 0x13, 0x54, 0x00, 0x17, 0x49, 0x46, 0x28, 0x39, 0x34, 0x0e, 0x1b,
// Dst addr
0x26, 0x07, 0xf8, 0xb0, 0x40, 0x0a, 0x08, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x0e,
// UDP header
0xd4, 0x04, 0x01, 0xbb, 0x00, 0x29, 0x96, 0x84,
// Payload
0x5c, 0x06, 0xae, 0x85, 0x02, 0xf5, 0xdb, 0x90, 0xe0, 0xe0, 0x93, 0xed, 0x9a, 0xd9, 0x92, 0x69, 0xbe, 0x36, 0x8a, 0x7d, 0xd7, 0xce, 0xd0, 0x8a, 0xf2, 0x51, 0x95, 0xff, 0xb6, 0x92, 0x70, 0x10, 0xd7,
}
var udp6RequestDecode = Parsed{
b: udp6RequestBuffer,
subofs: 40,
dataofs: 48,
length: len(udp6RequestBuffer),
IPVersion: 6,
IPProto: UDP,
Src: mustIPPort("[2001:559:bc13:5400:1749:4628:3934:e1b]:54276"),
Dst: mustIPPort("[2607:f8b0:400a:809::200e]:443"),
}
var udp4ReplyBuffer = []byte{
// IP header up to checksum
0x45, 0x00, 0x00, 0x29, 0x21, 0x52, 0x00, 0x00, 0x40, 0x11, 0x49, 0x5f,
// source IP
0x05, 0x06, 0x07, 0x08,
// destination IP
0x01, 0x02, 0x03, 0x04,
// UDP header
0x02, 0x37, 0x00, 0x7b, 0x00, 0x15, 0xd3, 0x9d,
// "reply_payload"
0x72, 0x65, 0x70, 0x6c, 0x79, 0x5f, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64,
}
var udp4ReplyDecode = Parsed{
b: udp4ReplyBuffer,
subofs: 20,
dataofs: 28,
length: len(udp4ReplyBuffer),
IPProto: UDP,
Src: mustIPPort("1.2.3.4:567"),
Dst: mustIPPort("5.6.7.8:123"),
}
// First TCP fragment of a packet with leading 24 bytes of 'a's
var tcp4MediumFragmentBuffer = []byte{
// IP header up to checksum
0x45, 0x20, 0x00, 0x4c, 0x2c, 0x62, 0x20, 0x00, 0x22, 0x06, 0x3a, 0x0f,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
// TCP header
0x00, 0x50, 0xf3, 0x8c, 0x58, 0xad, 0x60, 0x94, 0x25, 0xe4, 0x23, 0xa8, 0x80,
0x10, 0x01, 0xfd, 0xc6, 0x6e, 0x00, 0x00, 0x01, 0x01, 0x08, 0x0a, 0xff, 0x60,
0xfb, 0xfe, 0xba, 0x31, 0x78, 0x6a,
// data
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
}
var tcp4MediumFragmentDecode = Parsed{
b: tcp4MediumFragmentBuffer,
subofs: 20,
dataofs: 52,
length: len(tcp4MediumFragmentBuffer),
IPVersion: 4,
IPProto: TCP,
Src: mustIPPort("1.2.3.4:80"),
Dst: mustIPPort("5.6.7.8:62348"),
TCPFlags: 0x10,
}
var tcp4ShortFragmentBuffer = []byte{
// IP header up to checksum
0x45, 0x20, 0x00, 0x1e, 0x2c, 0x62, 0x20, 0x00, 0x22, 0x06, 0x3c, 0x4f,
// source IP
0x01, 0x02, 0x03, 0x04,
// destination IP
0x05, 0x06, 0x07, 0x08,
// partial TCP header
0x00, 0x50, 0xf3, 0x8c, 0x58, 0xad, 0x60, 0x94, 0x00, 0x00,
}
var tcp4ShortFragmentDecode = Parsed{
b: tcp4ShortFragmentBuffer,
subofs: 20,
dataofs: 0,
length: len(tcp4ShortFragmentBuffer),
// short fragments are rejected (marked unknown) to avoid header attacks as described in RFC 1858
IPProto: ipproto.Unknown,
IPVersion: 4,
Src: mustIPPort("1.2.3.4:0"),
Dst: mustIPPort("5.6.7.8:0"),
}
var igmpPacketBuffer = []byte{
// IP header up to checksum
0x46, 0xc0, 0x00, 0x20, 0x00, 0x00, 0x40, 0x00, 0x01, 0x02, 0x41, 0x22,
// source IP
0xc0, 0xa8, 0x01, 0x52,
// destination IP
0xe0, 0x00, 0x00, 0xfb,
// IGMP Membership Report
0x94, 0x04, 0x00, 0x00, 0x16, 0x00, 0x09, 0x04, 0xe0, 0x00, 0x00, 0xfb,
//0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}
var igmpPacketDecode = Parsed{
b: igmpPacketBuffer,
subofs: 24,
length: len(igmpPacketBuffer),
IPVersion: 4,
IPProto: IGMP,
Src: mustIPPort("192.168.1.82:0"),
Dst: mustIPPort("224.0.0.251:0"),
}
var ipv4TSMPBuffer = []byte{
// IPv4 header:
0x45, 0x00,
0x00, 0x1b, // 20 + 7 bytes total
0x00, 0x00, // ID
0x00, 0x00, // Fragment
0x40, // TTL
byte(TSMP),
0x5f, 0xc3, // header checksum (wrong here)
// source IP:
0x64, 0x5e, 0x0c, 0x0e,
// dest IP:
0x64, 0x4a, 0x46, 0x03,
byte(TSMPTypeRejectedConn),
byte(TCP),
byte(RejectedDueToACLs),
0x00, 123, // src port
0x00, 80, // dst port
}
var ipv4TSMPDecode = Parsed{
b: ipv4TSMPBuffer,
subofs: 20,
dataofs: 20,
length: 27,
IPVersion: 4,
IPProto: TSMP,
Src: mustIPPort("100.94.12.14:0"),
Dst: mustIPPort("100.74.70.3:0"),
}
// IPv4 SCTP
var sctpBuffer = []byte{
// IPv4 header:
0x45, 0x00,
0x00, 0x20, // 20 + 12 bytes total
0x00, 0x00, // ID
0x00, 0x00, // Fragment
0x40, // TTL
byte(SCTP),
// Checksum, unchecked:
1, 2,
// source IP:
0x64, 0x5e, 0x0c, 0x0e,
// dest IP:
0x64, 0x4a, 0x46, 0x03,
// Src Port, Dest Port:
0x00, 0x7b, 0x01, 0xc8,
// Verification tag:
1, 2, 3, 4,
// Checksum: (unchecked)
5, 6, 7, 8,
}
var sctpDecode = Parsed{
b: sctpBuffer,
subofs: 20,
length: 20 + 12,
IPVersion: 4,
IPProto: SCTP,
Src: mustIPPort("100.94.12.14:123"),
Dst: mustIPPort("100.74.70.3:456"),
}
func TestParsedString(t *testing.T) {
tests := []struct {
name string
qdecode Parsed
want string
}{
{"tcp4", tcp4PacketDecode, "TCP{1.2.3.4:123 > 5.6.7.8:567}"},
{"tcp6", tcp6RequestDecode, "TCP{[2001:559:bc13:5400:1749:4628:3934:e1b]:42080 > [2607:f8b0:400a:809::200e]:80}"},
{"udp4", udp4RequestDecode, "UDP{1.2.3.4:123 > 5.6.7.8:567}"},
{"udp6", udp6RequestDecode, "UDP{[2001:559:bc13:5400:1749:4628:3934:e1b]:54276 > [2607:f8b0:400a:809::200e]:443}"},
{"icmp4", icmp4RequestDecode, "ICMPv4{1.2.3.4:0 > 5.6.7.8:0}"},
{"icmp6", icmp6PacketDecode, "ICMPv6{[fe80::fb57:1dea:9c39:8fb7]:0 > [ff02::2]:0}"},
{"igmp", igmpPacketDecode, "IGMP{192.168.1.82:0 > 224.0.0.251:0}"},
{"unknown", unknownPacketDecode, "Unknown{???}"},
{"ipv4_tsmp", ipv4TSMPDecode, "TSMP{100.94.12.14:0 > 100.74.70.3:0}"},
{"sctp", sctpDecode, "SCTP{100.94.12.14:123 > 100.74.70.3:456}"},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got := tt.qdecode.String()
if got != tt.want {
t.Errorf("got %q; want %q", got, tt.want)
}
})
}
err := tstest.MinAllocsPerRun(t, 1, func() {
sinkString = tests[0].qdecode.String()
})
if err != nil {
t.Error(err)
}
}
// mustHexDecode is like hex.DecodeString, but panics on error
// and ignores whitespace in s.
func mustHexDecode(s string) []byte {
return must.Get(hex.DecodeString(strings.Map(func(r rune) rune {
if unicode.IsSpace(r) {
return -1
}
return r
}, s)))
}
func TestDecode(t *testing.T) {
tests := []struct {
name string
buf []byte
want Parsed
}{
{"icmp4", icmp4RequestBuffer, icmp4RequestDecode},
{"icmp6", icmp6PacketBuffer, icmp6PacketDecode},
{"tcp4", tcp4PacketBuffer, tcp4PacketDecode},
{"tcp6", tcp6RequestBuffer, tcp6RequestDecode},
{"udp4", udp4RequestBuffer, udp4RequestDecode},
{"udp6", udp6RequestBuffer, udp6RequestDecode},
{"igmp", igmpPacketBuffer, igmpPacketDecode},
{"unknown", unknownPacketBuffer, unknownPacketDecode},
{"invalid4", invalid4RequestBuffer, invalid4RequestDecode},
{"ipv4_tsmp", ipv4TSMPBuffer, ipv4TSMPDecode},
{"ipv4_sctp", sctpBuffer, sctpDecode},
{"ipv4_frag", tcp4MediumFragmentBuffer, tcp4MediumFragmentDecode},
{"ipv4_fragtooshort", tcp4ShortFragmentBuffer, tcp4ShortFragmentDecode},
{"ip97", mustHexDecode("4500 0019 d186 4000 4061 751d 644a 4603 6449 e549 6865 6c6c 6f"), Parsed{
IPVersion: 4,
IPProto: 97,
Src: netip.MustParseAddrPort("100.74.70.3:0"),
Dst: netip.MustParseAddrPort("100.73.229.73:0"),
b: mustHexDecode("4500 0019 d186 4000 4061 751d 644a 4603 6449 e549 6865 6c6c 6f"),
length: 25,
subofs: 20,
}},
// This packet purports to use protocol 0xFF, which is verboten and
// used internally as a sentinel value for fragments. So test that
// we map packets using 0xFF to Unknown (0) instead.
{"bogus_proto_ff", mustHexDecode("4500 0019 d186 4000 40" + "FF" /* bogus FF */ + " 751d 644a 4603 6449 e549 6865 6c6c 6f"), Parsed{
IPVersion: 4,
IPProto: ipproto.Unknown, // 0, not bogus 0xFF
Src: netip.MustParseAddrPort("100.74.70.3:0"),
Dst: netip.MustParseAddrPort("100.73.229.73:0"),
b: mustHexDecode("4500 0019 d186 4000 40" + "FF" /* bogus FF */ + " 751d 644a 4603 6449 e549 6865 6c6c 6f"),
length: 25,
subofs: 20,
}},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var got Parsed
got.Decode(tt.buf)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("mismatch\n got: %s %#v\nwant: %s %#v", got.String(), got, tt.want.String(), tt.want)
}
})
}
err := tstest.MinAllocsPerRun(t, 0, func() {
var got Parsed
got.Decode(tests[0].buf)
})
if err != nil {
t.Error(err)
}
}
func BenchmarkDecode(b *testing.B) {
benches := []struct {
name string
buf []byte
}{
{"tcp4", tcp4PacketBuffer},
{"tcp6", tcp6RequestBuffer},
{"udp4", udp4RequestBuffer},
{"udp6", udp6RequestBuffer},
{"icmp4", icmp4RequestBuffer},
{"icmp6", icmp6PacketBuffer},
{"igmp", igmpPacketBuffer},
{"unknown", unknownPacketBuffer},
}
for _, bench := range benches {
b.Run(bench.name, func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
var p Parsed
p.Decode(bench.buf)
}
})
}
}
func TestMarshalRequest(t *testing.T) {
// Too small to hold our packets, but only barely.
var small [20]byte
var large [64]byte
icmpHeader := icmp4RequestDecode.ICMP4Header()
udpHeader := udp4RequestDecode.UDP4Header()
tests := []struct {
name string
header Header
want []byte
}{
{"icmp", &icmpHeader, icmp4RequestBuffer},
{"udp", &udpHeader, udp4RequestBuffer},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
err := tt.header.Marshal(small[:])
if err != errSmallBuffer {
t.Errorf("got err: nil; want: %s", errSmallBuffer)
}
dataOffset := tt.header.Len()
dataLength := copy(large[dataOffset:], []byte("request_payload"))
end := dataOffset + dataLength
err = tt.header.Marshal(large[:end])
if err != nil {
t.Errorf("got err: %s; want nil", err)
}
if !bytes.Equal(large[:end], tt.want) {
t.Errorf("got %x; want %x", large[:end], tt.want)
}
})
}
}
func TestMarshalResponse(t *testing.T) {
var buf [64]byte
icmpHeader := icmp4RequestDecode.ICMP4Header()
udpHeader := udp4RequestDecode.UDP4Header()
type HeaderToResponser interface {
Header
// ToResponse transforms the header into one for a response packet.
// For instance, this swaps the source and destination IPs.
ToResponse()
}
tests := []struct {
name string
header HeaderToResponser
want []byte
}{
{"icmp", &icmpHeader, icmp4ReplyBuffer},
{"udp", &udpHeader, udp4ReplyBuffer},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
tt.header.ToResponse()
dataOffset := tt.header.Len()
dataLength := copy(buf[dataOffset:], []byte("reply_payload"))
end := dataOffset + dataLength
err := tt.header.Marshal(buf[:end])
if err != nil {
t.Errorf("got err: %s; want nil", err)
}
if !bytes.Equal(buf[:end], tt.want) {
t.Errorf("got %x; want %x", buf[:end], tt.want)
}
})
}
}
var sinkString string
func BenchmarkString(b *testing.B) {
benches := []struct {
name string
buf []byte
}{
{"tcp4", tcp4PacketBuffer},
{"tcp6", tcp6RequestBuffer},
{"udp4", udp4RequestBuffer},
{"udp6", udp6RequestBuffer},
{"icmp4", icmp4RequestBuffer},
{"icmp6", icmp6PacketBuffer},
{"igmp", igmpPacketBuffer},
{"unknown", unknownPacketBuffer},
}
for _, bench := range benches {
b.Run(bench.name, func(b *testing.B) {
b.ReportAllocs()
var p Parsed
p.Decode(bench.buf)
b.ResetTimer()
for i := 0; i < b.N; i++ {
sinkString = p.String()
}
})
}
}