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Address TXT records > 255 characters; make language more consistent; separate section for root records #162

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merged 9 commits into from
Apr 3, 2024
Merged

Address TXT records > 255 characters; make language more consistent; separate section for root records #162

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072e174
clarify text on root records
Apr 3, 2024
efb4be7
text consistency
Apr 3, 2024
4f52a0c
update test vector with long vector
Apr 3, 2024
e2a9268
Merge branch 'main' into issue-94
decentralgabe Apr 3, 2024
b3e1773
update test vectors
Apr 3, 2024
3f6057c
update readmes
Apr 3, 2024
6ae2a1e
pr comment
Apr 3, 2024
d1ceeb0
update go version
Apr 3, 2024
5db77ba
update go dep
Apr 3, 2024
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79 changes: 50 additions & 29 deletions impl/internal/did/did.go
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Original file line number Diff line number Diff line change
Expand Up @@ -268,7 +268,7 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{controllerTxt},
Txt: chunkTextRecord(controllerTxt),
}
records = append(records, &controllerAnswer)
}
Expand All @@ -287,7 +287,7 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{akaTxt},
Txt: chunkTextRecord(akaTxt),
}
records = append(records, &akaAnswer)
}
Expand All @@ -301,7 +301,7 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{string(gateway)},
Txt: chunkTextRecord(string(gateway)),
}
records = append(records, &gatewayAnswer)
}
Expand Down Expand Up @@ -347,14 +347,18 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
}
txtRecord += fmt.Sprintf(";c=%s", vm.Controller)
}

if len(txtRecord) > 255 {
return nil, fmt.Errorf("key value exceeds 255 characters")
}
keyRecord := dns.TXT{
Hdr: dns.RR_Header{
Name: fmt.Sprintf("_%s._did.", recordIdentifier),
Rrtype: dns.TypeTXT,
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{txtRecord},
Txt: chunkTextRecord(txtRecord),
}

records = append(records, &keyRecord)
Expand Down Expand Up @@ -386,16 +390,12 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{svcTxt},
Txt: chunkTextRecord(svcTxt),
}

records = append(records, &serviceRecord)
svcIDs = append(svcIDs, recordIdentifier)
}
// add services to the root record
if len(svcIDs) != 0 {
rootRecord = append(rootRecord, fmt.Sprintf("svc=%s", strings.Join(svcIDs, ",")))
}

// add verification relationships to the root record
var authIDs []string
Expand Down Expand Up @@ -438,6 +438,11 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
rootRecord = append(rootRecord, fmt.Sprintf("del=%s", strings.Join(capabilityDelegationIDs, ",")))
}

// add services to the root record
if len(svcIDs) != 0 {
rootRecord = append(rootRecord, fmt.Sprintf("svc=%s", strings.Join(svcIDs, ",")))
}

// add the root record
rootAnswer := dns.TXT{
Hdr: dns.RR_Header{
Expand All @@ -463,7 +468,7 @@ func (d DHT) ToDNSPacket(doc did.Document, types []TypeIndex, gateways []Authori
Class: dns.ClassINET,
Ttl: 7200,
},
Txt: []string{"id=" + strings.Join(typesStr, ",")},
Txt: chunkTextRecord("id=" + strings.Join(typesStr, ",")),
}
records = append(records, &typesAnswer)
}
Expand Down Expand Up @@ -524,18 +529,21 @@ func (d DHT) FromDNSPacket(msg *dns.Msg) (*did.Document, []TypeIndex, []Authorit
switch record := rr.(type) {
case *dns.TXT:
if strings.HasPrefix(record.Hdr.Name, "_cnt") {
controllers := strings.Split(record.Txt[0], ",")
unchunkedTextRecord := unchunkTextRecord(record.Txt)
controllers := strings.Split(unchunkedTextRecord, ",")
if len(controllers) == 1 {
doc.Controller = controllers[0]
} else {
doc.Controller = controllers
}
}
if strings.HasPrefix(record.Hdr.Name, "_aka") {
doc.AlsoKnownAs = strings.Split(record.Txt[0], ",")
unchunkedTextRecord := unchunkTextRecord(record.Txt)
doc.AlsoKnownAs = strings.Split(unchunkedTextRecord, ",")
}
if strings.HasPrefix(record.Hdr.Name, "_k") {
data := parseTxtData(strings.Join(record.Txt, ","))
unchunkedTextRecord := unchunkTextRecord(record.Txt)
data := parseTxtData(unchunkedTextRecord)
vmID := data["id"]
keyType := keyTypeLookUp(data["t"])
keyBase64URL := data["k"]
Expand Down Expand Up @@ -598,20 +606,15 @@ func (d DHT) FromDNSPacket(msg *dns.Msg) (*did.Document, []TypeIndex, []Authorit
// add to key lookup (e.g. "k1" -> "key1")
keyLookup[strings.Split(record.Hdr.Name, ".")[0][1:]] = vmID
} else if strings.HasPrefix(record.Hdr.Name, "_s") {
data := parseTxtData(strings.Join(record.Txt, ","))
unchunkedTextRecord := unchunkTextRecord(record.Txt)
data := parseTxtData(unchunkedTextRecord)
sID := data["id"]
serviceType := data["t"]
serviceEndpoint := data["se"]
var serviceEndpointValue any
if strings.Contains(serviceEndpoint, ",") {
serviceEndpointValue = strings.Split(serviceEndpoint, ",")
} else {
serviceEndpointValue = serviceEndpoint
}
service := did.Service{
ID: d.String() + "#" + sID,
Type: serviceType,
ServiceEndpoint: serviceEndpointValue,
ServiceEndpoint: strings.Split(serviceEndpoint, ","),
}
if data["sig"] != "" {
if strings.Contains(data["sig"], ",") {
Expand All @@ -630,10 +633,11 @@ func (d DHT) FromDNSPacket(msg *dns.Msg) (*did.Document, []TypeIndex, []Authorit
doc.Services = append(doc.Services, service)

} else if record.Hdr.Name == "_typ._did." {
if record.Txt[0] == "" || len(record.Txt) != 1 {
return nil, nil, nil, fmt.Errorf("invalid types record")
if record.Txt[0] == "" {
return nil, nil, nil, fmt.Errorf("types record is empty")
}
typesStr := strings.Split(strings.TrimPrefix(record.Txt[0], "id="), ",")
unchunkedTextRecord := unchunkTextRecord(record.Txt)
typesStr := strings.Split(strings.TrimPrefix(unchunkedTextRecord, "id="), ",")
for _, t := range typesStr {
tInt, err := strconv.Atoi(t)
if err != nil {
Expand All @@ -642,13 +646,14 @@ func (d DHT) FromDNSPacket(msg *dns.Msg) (*did.Document, []TypeIndex, []Authorit
types = append(types, TypeIndex(tInt))
}
} else if record.Hdr.Name == fmt.Sprintf("_did.%s.", suffix) && record.Hdr.Rrtype == dns.TypeNS {
if record.Txt[0] == "" || len(record.Txt) != 1 {
return nil, nil, nil, fmt.Errorf("invalid gateways record: %s", record.String())
if record.Txt[0] == "" {
return nil, nil, nil, fmt.Errorf("gateway record is empty")
}
gateways = append(gateways, AuthoritativeGateway(record.Txt[0]))
unchunkedTextRecord := unchunkTextRecord(record.Txt)
gateways = append(gateways, AuthoritativeGateway(unchunkedTextRecord))
} else if record.Hdr.Name == fmt.Sprintf("_did.%s.", suffix) && record.Hdr.Rrtype == dns.TypeTXT {
rootData := strings.Join(record.Txt, ";")
rootItems := strings.Split(rootData, ";")
unchunkedTextRecord := unchunkTextRecord(record.Txt)
rootItems := strings.Split(unchunkedTextRecord, ";")

seenVersion := false
for _, item := range rootItems {
Expand Down Expand Up @@ -792,3 +797,19 @@ func keyTypeForJWK(jwk jwx.PublicKeyJWK) int {
}
return -1
}

// chunkTextRecord splits a text record into chunks of 255 characters
func chunkTextRecord(record string) []string {
var chunks []string
for len(record) > 255 {
chunks = append(chunks, record[:255])
record = record[255:]
}
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TIL (thanks chad!) that len(str) returns the number of bytes. This may not be equivalent to the number of chars. For instance, len("£") returns 2.

Given the above, if you want to actually do this into 255 chars, then see the function below.

// SplitString255 splits a string into substrings of up to 255 characters.
func SplitString255(input string) []string {
	var chunks []string
	runeArray := []rune(input) // Convert to rune slice to properly handle multi-byte characters

	for len(runeArray) > 0 {
		if len(runeArray) <= 255 {
			chunks = append(chunks, string(runeArray))
			break
		}

		chunks = append(chunks, string(runeArray[:255]))
		runeArray = runeArray[255:]
	}

	return chunks
}

But the real question is whether the library should allow setting a value in a DID Document which contains values outside the ASCII range. I think the library should. And thus, I believe the value should be base64url encoded before doing chunking, so there are no issues with existing DNS systems. If you agree, then my suggestion doesn't matter, as all ASCII chars are 1-byte when encoded in UTF-8.

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this is a great catch about bytes vs character sizes - thank you
I am opposed to b64 encoding because of size increases

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I am going to merge, but please feel free to open an issue to support non-ASCII characters.

chunks = append(chunks, record)
return chunks
}

// unchunkTextRecord joins chunks of a text record
func unchunkTextRecord(chunks []string) string {
return strings.Join(chunks, "")
}
31 changes: 21 additions & 10 deletions impl/internal/did/did_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -188,7 +188,7 @@ func TestToDNSPacket(t *testing.T) {
{
ID: "vcs",
Type: "VerifiableCredentialService",
ServiceEndpoint: "https://example.com/vc/",
ServiceEndpoint: []string{"https://example.com/vc/"},
Sig: []string{"1", "2"},
Enc: "3",
},
Expand Down Expand Up @@ -227,10 +227,10 @@ func TestToDNSPacket(t *testing.T) {

func TestVectors(t *testing.T) {
type testVectorDNSRecord struct {
Name string `json:"name"`
RecordType string `json:"type"`
TTL string `json:"ttl"`
Record string `json:"rdata"`
Name string `json:"name"`
RecordType string `json:"type"`
TTL string `json:"ttl"`
Record []string `json:"rdata"`
}

t.Run("test vector 1", func(t *testing.T) {
Expand Down Expand Up @@ -275,7 +275,7 @@ func TestVectors(t *testing.T) {
s := record.String()
if strings.Contains(s, expectedRecord.RecordType) &&
strings.Contains(s, expectedRecord.TTL) &&
strings.Contains(s, expectedRecord.Record) {
strings.Contains(s, strings.Join(expectedRecord.Record, "")) {
matchedRecords[i] = true // Mark as matched
break
}
Expand Down Expand Up @@ -370,7 +370,7 @@ func TestVectors(t *testing.T) {
s := record.String()
if strings.Contains(s, expectedRecord.RecordType) &&
strings.Contains(s, expectedRecord.TTL) &&
strings.Contains(s, expectedRecord.Record) {
strings.Contains(s, strings.Join(expectedRecord.Record, "")) {
matchedRecords[i] = true // Mark as matched
break
}
Expand Down Expand Up @@ -418,6 +418,13 @@ func TestVectors(t *testing.T) {
Purposes: []did.PublicKeyPurpose{did.KeyAgreement},
},
},
Services: []did.Service{
{
ID: "service-1",
Type: "TestLongService",
ServiceEndpoint: []string{"https://test-lllllllllllllllllllllllllllllllllllooooooooooooooooooooonnnnnnnnnnnnnnnnnnngggggggggggggggggggggggggggggggggggggsssssssssssssssssssssssssseeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrrvvvvvvvvvvvvvvvvvvvviiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiccccccccccccccccccccccccccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee.com/1"},
},
},
})
require.NoError(t, err)
require.NotEmpty(t, doc)
Expand All @@ -432,7 +439,6 @@ func TestVectors(t *testing.T) {
require.NoError(t, err)

assert.JSONEq(t, string(expectedDIDDocJSON), string(docJSON))

didID := DHT(doc.ID)
packet, err := didID.ToDNSPacket(*doc, nil, []AuthoritativeGateway{"gateway1.example-did-dht-gateway.com."})
require.NoError(t, err)
Expand All @@ -452,8 +458,13 @@ func TestVectors(t *testing.T) {
if record.Header().Name == expectedRecord.Name {
s := record.String()
if strings.Contains(s, expectedRecord.RecordType) &&
strings.Contains(s, expectedRecord.TTL) &&
strings.Contains(s, expectedRecord.Record) {
strings.Contains(s, expectedRecord.TTL) {
// make sure all parts of the record are contained within s
for _, r := range expectedRecord.Record {
if !strings.Contains(s, r) {
break
}
}
matchedRecords[i] = true // Mark as matched
break
}
Expand Down
4 changes: 2 additions & 2 deletions impl/internal/did/testdata/vector-1-dns-records.json
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,12 @@
"name": "_did.cyuoqaf7itop8ohww4yn5ojg13qaq83r9zihgqntc5i9zwrfdfoo.",
"type": "TXT",
"ttl": "7200",
"rdata": "v=0;vm=k0;auth=k0;asm=k0;inv=k0;del=k0"
"rdata": ["v=0;vm=k0;auth=k0;asm=k0;inv=k0;del=k0"]
},
{
"name": "_k0._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "id=0;t=0;k=YCcHYL2sYNPDlKaALcEmll2HHyT968M4UWbr-9CFGWE"
"rdata": ["id=0;t=0;k=YCcHYL2sYNPDlKaALcEmll2HHyT968M4UWbr-9CFGWE"]
}
]
18 changes: 9 additions & 9 deletions impl/internal/did/testdata/vector-2-dns-records.json
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -3,54 +3,54 @@
"name": "_did.cyuoqaf7itop8ohww4yn5ojg13qaq83r9zihgqntc5i9zwrfdfoo.",
"type": "NS",
"ttl": "7200",
"rdata": "gateway1.example-did-dht-gateway.com."
"rdata": ["gateway1.example-did-dht-gateway.com."]
},
{
"name": "_did.cyuoqaf7itop8ohww4yn5ojg13qaq83r9zihgqntc5i9zwrfdfoo.",
"type": "NS",
"ttl": "7200",
"rdata": "gateway2.example-did-dht-gateway.com."
"rdata": ["gateway2.example-did-dht-gateway.com."]
},
{
"name": "_did.cyuoqaf7itop8ohww4yn5ojg13qaq83r9zihgqntc5i9zwrfdfoo.",
"type": "TXT",
"ttl": "7200",
"rdata": "v=0;vm=k0,k1;svc=s0;auth=k0;asm=k0,k1;inv=k0,k1;del=k0"
"rdata": ["v=0;vm=k0,k1;auth=k0;asm=k0,k1;inv=k0,k1;del=k0;svc=s0"]
},
{
"name": "_cnt._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "did:example:abcd"
"rdata": ["did:example:abcd"]
},
{
"name": "_aka._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "did:example:efgh,did:example:ijkl"
"rdata": ["did:example:efgh,did:example:ijkl"]
},
{
"name": "_k0._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "id=0;t=0;k=YCcHYL2sYNPDlKaALcEmll2HHyT968M4UWbr-9CFGWE"
"rdata": ["id=0;t=0;k=YCcHYL2sYNPDlKaALcEmll2HHyT968M4UWbr-9CFGWE"]
},
{
"name": "_k1._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "t=1;k=Atf6NCChxjWpnrfPt1WDVE4ipYVSvi4pXCq4SUjx0jT9"
"rdata": ["t=1;k=Atf6NCChxjWpnrfPt1WDVE4ipYVSvi4pXCq4SUjx0jT9"]
},
{
"name": "_s0._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "id=service-1;t=TestService;se=https://test-service.com/1,https://test-service.com/2"
"rdata": ["id=service-1;t=TestService;se=https://test-service.com/1,https://test-service.com/2"]
},
{
"name": "_typ._did.",
"type": "TXT",
"ttl": "7200",
"rdata": "id=1,2,3"
"rdata": ["id=1,2,3"]
}
]
23 changes: 15 additions & 8 deletions impl/internal/did/testdata/vector-3-did-document.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,23 +6,23 @@
"type": "JsonWebKey",
"controller": "did:dht:sr6jgmcc84xig18ix66qbiwnzeiumocaaybh13f5w97bfzus4pcy",
"publicKeyJwk": {
"kty": "OKP",
"crv": "Ed25519",
"x": "sTyTLYw-n1NI9X-84NaCuis1wZjAA8lku6f6Et5201g",
"kid": "0",
"alg": "Ed25519",
"kid": "0"
"crv": "Ed25519",
"kty": "OKP",
"x": "sTyTLYw-n1NI9X-84NaCuis1wZjAA8lku6f6Et5201g"
}
},
{
"id": "did:dht:sr6jgmcc84xig18ix66qbiwnzeiumocaaybh13f5w97bfzus4pcy#WVy5IWMa36AoyAXZDvPd5j9zxt2t-GjifDEV-DwgIdQ",
"type": "JsonWebKey",
"controller": "did:dht:sr6jgmcc84xig18ix66qbiwnzeiumocaaybh13f5w97bfzus4pcy",
"publicKeyJwk": {
"kty": "OKP",
"crv": "X25519",
"x": "3POE0_i2mGeZ2qiQCA3KcLfi1fZo0311CXFSIwt1nB4",
"kid": "WVy5IWMa36AoyAXZDvPd5j9zxt2t-GjifDEV-DwgIdQ",
"alg": "ECDH-ES+A128KW",
"kid": "WVy5IWMa36AoyAXZDvPd5j9zxt2t-GjifDEV-DwgIdQ"
"crv": "X25519",
"kty": "OKP",
"x": "3POE0_i2mGeZ2qiQCA3KcLfi1fZo0311CXFSIwt1nB4"
}
}
],
Expand All @@ -40,5 +40,12 @@
],
"capabilityDelegation": [
"did:dht:sr6jgmcc84xig18ix66qbiwnzeiumocaaybh13f5w97bfzus4pcy#0"
],
"service": [
{
"id": "did:dht:sr6jgmcc84xig18ix66qbiwnzeiumocaaybh13f5w97bfzus4pcy#service-1",
"type": "TestLongService",
"serviceEndpoint": ["https://test-lllllllllllllllllllllllllllllllllllooooooooooooooooooooonnnnnnnnnnnnnnnnnnngggggggggggggggggggggggggggggggggggggsssssssssssssssssssssssssseeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrrvvvvvvvvvvvvvvvvvvvviiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiccccccccccccccccccccccccccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee.com/1"]
}
]
}
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