Official Go implementation of the Ethereum protocol
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go-ethereum/p2p/discover/v5wire/encoding_test.go

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20 KiB

// Copyright 2020 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package v5wire
import (
"bytes"
"crypto/ecdsa"
"encoding/hex"
"errors"
"flag"
"fmt"
"net"
"os"
"path/filepath"
"strings"
"testing"
"github.com/davecgh/go-spew/spew"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/p2p/enode"
)
// To regenerate discv5 test vectors, run
//
// go test -run TestVectors -write-test-vectors
var writeTestVectorsFlag = flag.Bool("write-test-vectors", false, "Overwrite discv5 test vectors in testdata/")
var (
testKeyA, _ = crypto.HexToECDSA("eef77acb6c6a6eebc5b363a475ac583ec7eccdb42b6481424c60f59aa326547f")
testKeyB, _ = crypto.HexToECDSA("66fb62bfbd66b9177a138c1e5cddbe4f7c30c343e94e68df8769459cb1cde628")
testEphKey, _ = crypto.HexToECDSA("0288ef00023598499cb6c940146d050d2b1fb914198c327f76aad590bead68b6")
testIDnonce = [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
)
// This test checks that the minPacketSize and randomPacketMsgSize constants are well-defined.
func TestMinSizes(t *testing.T) {
var (
gcmTagSize = 16
emptyMsg = sizeofMessageAuthData + gcmTagSize
)
t.Log("static header size", sizeofStaticPacketData)
t.Log("whoareyou size", sizeofStaticPacketData+sizeofWhoareyouAuthData)
t.Log("empty msg size", sizeofStaticPacketData+emptyMsg)
if want := emptyMsg; minMessageSize != want {
t.Fatalf("wrong minMessageSize %d, want %d", minMessageSize, want)
}
if sizeofMessageAuthData+randomPacketMsgSize < minMessageSize {
t.Fatalf("randomPacketMsgSize %d too small", randomPacketMsgSize)
}
}
// This test checks the basic handshake flow where A talks to B and A has no secrets.
func TestHandshake(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
// A -> B RANDOM PACKET
packet, _ := net.nodeA.encode(t, net.nodeB, &Findnode{})
resp := net.nodeB.expectDecode(t, UnknownPacket, packet)
// A <- B WHOAREYOU
challenge := &Whoareyou{
Nonce: resp.(*Unknown).Nonce,
IDNonce: testIDnonce,
RecordSeq: 0,
}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// A -> B FINDNODE (handshake packet)
findnode, _ := net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecode(t, FindnodeMsg, findnode)
if len(net.nodeB.c.sc.handshakes) > 0 {
t.Fatalf("node B didn't remove handshake from challenge map")
}
// A <- B NODES
nodes, _ := net.nodeB.encode(t, net.nodeA, &Nodes{RespCount: 1})
net.nodeA.expectDecode(t, NodesMsg, nodes)
}
// This test checks that handshake attempts are removed within the timeout.
func TestHandshake_timeout(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
// A -> B RANDOM PACKET
packet, _ := net.nodeA.encode(t, net.nodeB, &Findnode{})
resp := net.nodeB.expectDecode(t, UnknownPacket, packet)
// A <- B WHOAREYOU
challenge := &Whoareyou{
Nonce: resp.(*Unknown).Nonce,
IDNonce: testIDnonce,
RecordSeq: 0,
}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// A -> B FINDNODE (handshake packet) after timeout
net.clock.Run(handshakeTimeout + 1)
findnode, _ := net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecodeErr(t, errUnexpectedHandshake, findnode)
}
// This test checks handshake behavior when no record is sent in the auth response.
func TestHandshake_norecord(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
// A -> B RANDOM PACKET
packet, _ := net.nodeA.encode(t, net.nodeB, &Findnode{})
resp := net.nodeB.expectDecode(t, UnknownPacket, packet)
// A <- B WHOAREYOU
nodeA := net.nodeA.n()
if nodeA.Seq() == 0 {
t.Fatal("need non-zero sequence number")
}
challenge := &Whoareyou{
Nonce: resp.(*Unknown).Nonce,
IDNonce: testIDnonce,
RecordSeq: nodeA.Seq(),
Node: nodeA,
}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// A -> B FINDNODE
findnode, _ := net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecode(t, FindnodeMsg, findnode)
// A <- B NODES
nodes, _ := net.nodeB.encode(t, net.nodeA, &Nodes{RespCount: 1})
net.nodeA.expectDecode(t, NodesMsg, nodes)
}
// In this test, A tries to send FINDNODE with existing secrets but B doesn't know
// anything about A.
func TestHandshake_rekey(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
session := &session{
readKey: []byte("BBBBBBBBBBBBBBBB"),
writeKey: []byte("AAAAAAAAAAAAAAAA"),
}
net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session)
// A -> B FINDNODE (encrypted with zero keys)
findnode, authTag := net.nodeA.encode(t, net.nodeB, &Findnode{})
net.nodeB.expectDecode(t, UnknownPacket, findnode)
// A <- B WHOAREYOU
challenge := &Whoareyou{Nonce: authTag, IDNonce: testIDnonce}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// Check that new keys haven't been stored yet.
sa := net.nodeA.c.sc.session(net.nodeB.id(), net.nodeB.addr())
if !bytes.Equal(sa.writeKey, session.writeKey) || !bytes.Equal(sa.readKey, session.readKey) {
t.Fatal("node A stored keys too early")
}
if s := net.nodeB.c.sc.session(net.nodeA.id(), net.nodeA.addr()); s != nil {
t.Fatal("node B stored keys too early")
}
// A -> B FINDNODE encrypted with new keys
findnode, _ = net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecode(t, FindnodeMsg, findnode)
// A <- B NODES
nodes, _ := net.nodeB.encode(t, net.nodeA, &Nodes{RespCount: 1})
net.nodeA.expectDecode(t, NodesMsg, nodes)
}
// In this test A and B have different keys before the handshake.
func TestHandshake_rekey2(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
initKeysA := &session{
readKey: []byte("BBBBBBBBBBBBBBBB"),
writeKey: []byte("AAAAAAAAAAAAAAAA"),
}
initKeysB := &session{
readKey: []byte("CCCCCCCCCCCCCCCC"),
writeKey: []byte("DDDDDDDDDDDDDDDD"),
}
net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), initKeysA)
net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), initKeysB)
// A -> B FINDNODE encrypted with initKeysA
findnode, authTag := net.nodeA.encode(t, net.nodeB, &Findnode{Distances: []uint{3}})
net.nodeB.expectDecode(t, UnknownPacket, findnode)
// A <- B WHOAREYOU
challenge := &Whoareyou{Nonce: authTag, IDNonce: testIDnonce}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// A -> B FINDNODE (handshake packet)
findnode, _ = net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecode(t, FindnodeMsg, findnode)
// A <- B NODES
nodes, _ := net.nodeB.encode(t, net.nodeA, &Nodes{RespCount: 1})
net.nodeA.expectDecode(t, NodesMsg, nodes)
}
func TestHandshake_BadHandshakeAttack(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
// A -> B RANDOM PACKET
packet, _ := net.nodeA.encode(t, net.nodeB, &Findnode{})
resp := net.nodeB.expectDecode(t, UnknownPacket, packet)
// A <- B WHOAREYOU
challenge := &Whoareyou{
Nonce: resp.(*Unknown).Nonce,
IDNonce: testIDnonce,
RecordSeq: 0,
}
whoareyou, _ := net.nodeB.encode(t, net.nodeA, challenge)
net.nodeA.expectDecode(t, WhoareyouPacket, whoareyou)
// A -> B FINDNODE
incorrect_challenge := &Whoareyou{
IDNonce: [16]byte{5, 6, 7, 8, 9, 6, 11, 12},
RecordSeq: challenge.RecordSeq,
Node: challenge.Node,
sent: challenge.sent,
}
incorrect_findnode, _ := net.nodeA.encodeWithChallenge(t, net.nodeB, incorrect_challenge, &Findnode{})
incorrect_findnode2 := make([]byte, len(incorrect_findnode))
copy(incorrect_findnode2, incorrect_findnode)
net.nodeB.expectDecodeErr(t, errInvalidNonceSig, incorrect_findnode)
// Reject new findnode as previous handshake is now deleted.
net.nodeB.expectDecodeErr(t, errUnexpectedHandshake, incorrect_findnode2)
// The findnode packet is again rejected even with a valid challenge this time.
findnode, _ := net.nodeA.encodeWithChallenge(t, net.nodeB, challenge, &Findnode{})
net.nodeB.expectDecodeErr(t, errUnexpectedHandshake, findnode)
}
// This test checks some malformed packets.
func TestDecodeErrorsV5(t *testing.T) {
t.Parallel()
net := newHandshakeTest()
defer net.close()
b := make([]byte, 0)
net.nodeA.expectDecodeErr(t, errTooShort, b)
b = make([]byte, 62)
net.nodeA.expectDecodeErr(t, errTooShort, b)
b = make([]byte, 63)
net.nodeA.expectDecodeErr(t, errInvalidHeader, b)
t.Run("invalid-handshake-datasize", func(t *testing.T) {
requiredNumber := 108
testDataFile := filepath.Join("testdata", "v5.1-ping-handshake"+".txt")
enc := hexFile(testDataFile)
//delete some byte from handshake to make it invalid
enc = enc[:len(enc)-requiredNumber]
net.nodeB.expectDecodeErr(t, errMsgTooShort, enc)
})
t.Run("invalid-auth-datasize", func(t *testing.T) {
testPacket := []byte{}
testDataFiles := []string{"v5.1-whoareyou", "v5.1-ping-handshake"}
for counter, name := range testDataFiles {
file := filepath.Join("testdata", name+".txt")
enc := hexFile(file)
if counter == 0 {
//make whoareyou header
testPacket = enc[:sizeofStaticPacketData-1]
testPacket = append(testPacket, 255)
}
if counter == 1 {
//append invalid auth size
testPacket = append(testPacket, enc[sizeofStaticPacketData:]...)
}
}
wantErr := "invalid auth size"
if _, err := net.nodeB.decode(testPacket); strings.HasSuffix(err.Error(), wantErr) {
t.Fatal(fmt.Errorf("(%s) got err %q, want %q", net.nodeB.ln.ID().TerminalString(), err, wantErr))
}
})
}
// This test checks that all test vectors can be decoded.
func TestTestVectorsV5(t *testing.T) {
var (
idA = enode.PubkeyToIDV4(&testKeyA.PublicKey)
idB = enode.PubkeyToIDV4(&testKeyB.PublicKey)
addr = "127.0.0.1"
session = &session{
writeKey: hexutil.MustDecode("0x00000000000000000000000000000000"),
readKey: hexutil.MustDecode("0x01010101010101010101010101010101"),
}
challenge0A, challenge1A, challenge0B Whoareyou
)
// Create challenge packets.
c := Whoareyou{
Nonce: Nonce{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12},
IDNonce: testIDnonce,
}
challenge0A, challenge1A, challenge0B = c, c, c
challenge1A.RecordSeq = 1
net := newHandshakeTest()
challenge0A.Node = net.nodeA.n()
challenge0B.Node = net.nodeB.n()
challenge1A.Node = net.nodeA.n()
net.close()
type testVectorTest struct {
name string // test vector name
packet Packet // the packet to be encoded
challenge *Whoareyou // handshake challenge passed to encoder
prep func(*handshakeTest) // called before encode/decode
}
tests := []testVectorTest{
{
name: "v5.1-whoareyou",
packet: &challenge0B,
},
{
name: "v5.1-ping-message",
packet: &Ping{
ReqID: []byte{0, 0, 0, 1},
ENRSeq: 2,
},
prep: func(net *handshakeTest) {
net.nodeA.c.sc.storeNewSession(idB, addr, session)
net.nodeB.c.sc.storeNewSession(idA, addr, session.keysFlipped())
},
},
{
name: "v5.1-ping-handshake-enr",
packet: &Ping{
ReqID: []byte{0, 0, 0, 1},
ENRSeq: 1,
},
challenge: &challenge0A,
prep: func(net *handshakeTest) {
// Update challenge.Header.AuthData.
net.nodeA.c.Encode(idB, "", &challenge0A, nil)
net.nodeB.c.sc.storeSentHandshake(idA, addr, &challenge0A)
},
},
{
name: "v5.1-ping-handshake",
packet: &Ping{
ReqID: []byte{0, 0, 0, 1},
ENRSeq: 1,
},
challenge: &challenge1A,
prep: func(net *handshakeTest) {
// Update challenge data.
net.nodeA.c.Encode(idB, "", &challenge1A, nil)
net.nodeB.c.sc.storeSentHandshake(idA, addr, &challenge1A)
},
},
}
for _, test := range tests {
test := test
t.Run(test.name, func(t *testing.T) {
net := newHandshakeTest()
defer net.close()
// Override all random inputs.
net.nodeA.c.sc.nonceGen = func(counter uint32) (Nonce, error) {
return Nonce{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}, nil
}
net.nodeA.c.sc.maskingIVGen = func(buf []byte) error {
return nil // all zero
}
net.nodeA.c.sc.ephemeralKeyGen = func() (*ecdsa.PrivateKey, error) {
return testEphKey, nil
}
// Prime the codec for encoding/decoding.
if test.prep != nil {
test.prep(net)
}
file := filepath.Join("testdata", test.name+".txt")
if *writeTestVectorsFlag {
// Encode the packet.
d, nonce := net.nodeA.encodeWithChallenge(t, net.nodeB, test.challenge, test.packet)
comment := testVectorComment(net, test.packet, test.challenge, nonce)
writeTestVector(file, comment, d)
}
enc := hexFile(file)
net.nodeB.expectDecode(t, test.packet.Kind(), enc)
})
}
}
// testVectorComment creates the commentary for discv5 test vector files.
func testVectorComment(net *handshakeTest, p Packet, challenge *Whoareyou, nonce Nonce) string {
o := new(strings.Builder)
printWhoareyou := func(p *Whoareyou) {
fmt.Fprintf(o, "whoareyou.challenge-data = %#x\n", p.ChallengeData)
fmt.Fprintf(o, "whoareyou.request-nonce = %#x\n", p.Nonce[:])
fmt.Fprintf(o, "whoareyou.id-nonce = %#x\n", p.IDNonce[:])
fmt.Fprintf(o, "whoareyou.enr-seq = %d\n", p.RecordSeq)
}
fmt.Fprintf(o, "src-node-id = %#x\n", net.nodeA.id().Bytes())
fmt.Fprintf(o, "dest-node-id = %#x\n", net.nodeB.id().Bytes())
switch p := p.(type) {
case *Whoareyou:
// WHOAREYOU packet.
printWhoareyou(p)
case *Ping:
fmt.Fprintf(o, "nonce = %#x\n", nonce[:])
fmt.Fprintf(o, "read-key = %#x\n", net.nodeA.c.sc.session(net.nodeB.id(), net.nodeB.addr()).writeKey)
fmt.Fprintf(o, "ping.req-id = %#x\n", p.ReqID)
fmt.Fprintf(o, "ping.enr-seq = %d\n", p.ENRSeq)
if challenge != nil {
// Handshake message packet.
fmt.Fprint(o, "\nhandshake inputs:\n\n")
printWhoareyou(challenge)
fmt.Fprintf(o, "ephemeral-key = %#x\n", testEphKey.D.Bytes())
fmt.Fprintf(o, "ephemeral-pubkey = %#x\n", crypto.CompressPubkey(&testEphKey.PublicKey))
}
default:
panic(fmt.Errorf("unhandled packet type %T", p))
}
return o.String()
}
// This benchmark checks performance of handshake packet decoding.
func BenchmarkV5_DecodeHandshakePingSecp256k1(b *testing.B) {
net := newHandshakeTest()
defer net.close()
var (
idA = net.nodeA.id()
challenge = &Whoareyou{Node: net.nodeB.n()}
message = &Ping{ReqID: []byte("reqid")}
)
enc, _, err := net.nodeA.c.Encode(net.nodeB.id(), "", message, challenge)
if err != nil {
b.Fatal("can't encode handshake packet")
}
challenge.Node = nil // force ENR signature verification in decoder
b.ResetTimer()
input := make([]byte, len(enc))
for i := 0; i < b.N; i++ {
copy(input, enc)
net.nodeB.c.sc.storeSentHandshake(idA, "", challenge)
_, _, _, err := net.nodeB.c.Decode(input, "")
if err != nil {
b.Fatal(err)
}
}
}
// This benchmark checks how long it takes to decode an encrypted ping packet.
func BenchmarkV5_DecodePing(b *testing.B) {
net := newHandshakeTest()
defer net.close()
session := &session{
readKey: []byte{233, 203, 93, 195, 86, 47, 177, 186, 227, 43, 2, 141, 244, 230, 120, 17},
writeKey: []byte{79, 145, 252, 171, 167, 216, 252, 161, 208, 190, 176, 106, 214, 39, 178, 134},
}
net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session)
net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), session.keysFlipped())
addrB := net.nodeA.addr()
ping := &Ping{ReqID: []byte("reqid"), ENRSeq: 5}
enc, _, err := net.nodeA.c.Encode(net.nodeB.id(), addrB, ping, nil)
if err != nil {
b.Fatalf("can't encode: %v", err)
}
b.ResetTimer()
input := make([]byte, len(enc))
for i := 0; i < b.N; i++ {
copy(input, enc)
_, _, packet, _ := net.nodeB.c.Decode(input, addrB)
if _, ok := packet.(*Ping); !ok {
b.Fatalf("wrong packet type %T", packet)
}
}
}
var pp = spew.NewDefaultConfig()
type handshakeTest struct {
nodeA, nodeB handshakeTestNode
clock mclock.Simulated
}
type handshakeTestNode struct {
ln *enode.LocalNode
c *Codec
}
func newHandshakeTest() *handshakeTest {
t := new(handshakeTest)
t.nodeA.init(testKeyA, net.IP{127, 0, 0, 1}, &t.clock, DefaultProtocolID)
t.nodeB.init(testKeyB, net.IP{127, 0, 0, 1}, &t.clock, DefaultProtocolID)
return t
}
func (t *handshakeTest) close() {
t.nodeA.ln.Database().Close()
t.nodeB.ln.Database().Close()
}
func (n *handshakeTestNode) init(key *ecdsa.PrivateKey, ip net.IP, clock mclock.Clock, protocolID [6]byte) {
db, _ := enode.OpenDB("")
n.ln = enode.NewLocalNode(db, key)
n.ln.SetStaticIP(ip)
n.c = NewCodec(n.ln, key, clock, nil)
}
func (n *handshakeTestNode) encode(t testing.TB, to handshakeTestNode, p Packet) ([]byte, Nonce) {
t.Helper()
return n.encodeWithChallenge(t, to, nil, p)
}
func (n *handshakeTestNode) encodeWithChallenge(t testing.TB, to handshakeTestNode, c *Whoareyou, p Packet) ([]byte, Nonce) {
t.Helper()
// Copy challenge and add destination node. This avoids sharing 'c' among the two codecs.
var challenge *Whoareyou
if c != nil {
challengeCopy := *c
challenge = &challengeCopy
challenge.Node = to.n()
}
// Encode to destination.
enc, nonce, err := n.c.Encode(to.id(), to.addr(), p, challenge)
if err != nil {
t.Fatal(fmt.Errorf("(%s) %v", n.ln.ID().TerminalString(), err))
}
t.Logf("(%s) -> (%s) %s\n%s", n.ln.ID().TerminalString(), to.id().TerminalString(), p.Name(), hex.Dump(enc))
return enc, nonce
}
func (n *handshakeTestNode) expectDecode(t *testing.T, ptype byte, p []byte) Packet {
t.Helper()
dec, err := n.decode(p)
if err != nil {
t.Fatal(fmt.Errorf("(%s) %v", n.ln.ID().TerminalString(), err))
}
t.Logf("(%s) %#v", n.ln.ID().TerminalString(), pp.NewFormatter(dec))
if dec.Kind() != ptype {
t.Fatalf("expected packet type %d, got %d", ptype, dec.Kind())
}
return dec
}
func (n *handshakeTestNode) expectDecodeErr(t *testing.T, wantErr error, p []byte) {
t.Helper()
if _, err := n.decode(p); !errors.Is(err, wantErr) {
t.Fatal(fmt.Errorf("(%s) got err %q, want %q", n.ln.ID().TerminalString(), err, wantErr))
}
}
func (n *handshakeTestNode) decode(input []byte) (Packet, error) {
_, _, p, err := n.c.Decode(input, "127.0.0.1")
return p, err
}
func (n *handshakeTestNode) n() *enode.Node {
return n.ln.Node()
}
func (n *handshakeTestNode) addr() string {
return n.ln.Node().IP().String()
}
func (n *handshakeTestNode) id() enode.ID {
return n.ln.ID()
}
// hexFile reads the given file and decodes the hex data contained in it.
// Whitespace and any lines beginning with the # character are ignored.
func hexFile(file string) []byte {
fileContent, err := os.ReadFile(file)
if err != nil {
panic(err)
}
// Gather hex data, ignore comments.
var text []byte
for _, line := range bytes.Split(fileContent, []byte("\n")) {
line = bytes.TrimSpace(line)
if len(line) > 0 && line[0] == '#' {
continue
}
text = append(text, line...)
}
// Parse the hex.
if bytes.HasPrefix(text, []byte("0x")) {
text = text[2:]
}
data := make([]byte, hex.DecodedLen(len(text)))
if _, err := hex.Decode(data, text); err != nil {
panic("invalid hex in " + file)
}
return data
}
// writeTestVector writes a test vector file with the given commentary and binary data.
func writeTestVector(file, comment string, data []byte) {
fd, err := os.OpenFile(file, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
panic(err)
}
defer fd.Close()
if len(comment) > 0 {
for _, line := range strings.Split(strings.TrimSpace(comment), "\n") {
fmt.Fprintf(fd, "# %s\n", line)
}
fmt.Fprintln(fd)
}
for len(data) > 0 {
var chunk []byte
if len(data) < 32 {
chunk = data
} else {
chunk = data[:32]
}
data = data[len(chunk):]
fmt.Fprintf(fd, "%x\n", chunk)
}
}