tls: add pcap capturing

x/tls/stringers_const.go

@@ -0,0 +1,122 @@
+package tls
+
+// StringConst methods name values as String does but always return a
+// compile-time constant, unlike String which formats an unrecognized value with
+// strconv. Wire values are attacker controlled, so decoders and logs on
+// embedded targets use StringConst and print the number alongside it.
+
+const (
+	// nameGREASE names the reserved values of RFC 8701, which carry no meaning.
+	nameGREASE = "GREASE"
+	// nameUnknown names a value this package does not recognize. Other RFCs may
+	// well define it: this is TLS 1.3 only.
+	nameUnknown = "unknown"
+)
+
+// StringConst returns the content type's name, or "unknown".
+func (v ContentType) StringConst() string {
+	switch v {
+	case ContentTypeInvalid, ContentTypeChangeCipherSpec, ContentTypeAlert,
+		ContentTypeHandshake, ContentTypeApplicationData:
+		return v.String()
+	}
+	return nameUnknown
+}
+
+// StringConst returns the handshake message type's name, or "unknown".
+func (v HandshakeType) StringConst() string {
+	switch v {
+	case HandshakeTypeClientHello, HandshakeTypeServerHello, HandshakeTypeNewSessionTicket,
+		HandshakeTypeEndOfEarlyData, HandshakeTypeEncryptedExtensions, HandshakeTypeCertificate,
+		HandshakeTypeCertificateRequest, HandshakeTypeCertificateVerify, HandshakeTypeFinished,
+		HandshakeTypeKeyUpdate, HandshakeTypeMessageHash:
+		return v.String()
+	}
+	return nameUnknown
+}
+
+// StringConst returns the extension type's name, "GREASE" or "unknown".
+func (v ExtensionType) StringConst() string {
+	switch v {
+	case ExtServerName, ExtMaxFragmentLength, ExtStatusRequest, ExtSupportedGroups,
+		ExtECPointFormats, ExtSignatureAlgorithms, ExtALPN, ExtSignedCertificateTimestamp,
+		ExtPadding, ExtExtendedMasterSecret, ExtCompressCertificate, ExtRecordSizeLimit,
+		ExtSessionTicket, ExtPreSharedKey, ExtEarlyData, ExtSupportedVersions, ExtCookie,
+		ExtPSKKeyExchangeModes, ExtCertificateAuthorities, ExtSignatureAlgorithmsCert,
+		ExtKeyShare, ExtApplicationSettings, ExtEncryptedClientHello, ExtRenegotiationInfo:
+		return v.String()
+	}
+	if IsGREASE(uint16(v)) {
+		return nameGREASE
+	}
+	return nameUnknown
+}
+
+// StringConst returns the alert level's name, or "unknown".
+func (v AlertLevel) StringConst() string {
+	switch v {
+	case AlertLevelWarning, AlertLevelFatal:
+		return v.String()
+	}
+	return nameUnknown
+}
+
+// StringConst returns the alert description's name, or "unknown".
+func (v AlertDescription) StringConst() string {
+	switch v {
+	case AlertCloseNotify, AlertUnexpectedMessage, AlertBadRecordMAC, AlertRecordOverflow,
+		AlertHandshakeFailure, AlertBadCertificate, AlertUnsupportedCertificate,
+		AlertCertificateRevoked, AlertCertificateExpired, AlertCertificateUnknown,
+		AlertIllegalParameter, AlertUnknownCA, AlertAccessDenied, AlertDecodeError,
+		AlertDecryptError, AlertProtocolVersion, AlertInsufficientSecurity,
+		AlertInternalError, AlertInappropriateFallback, AlertUserCanceled,
+		AlertMissingExtension, AlertUnsupportedExtension, AlertUnrecognizedName,
+		AlertBadCertificateStatusResponse, AlertUnknownPSKIdentity,
+		AlertCertificateRequired, AlertNoApplicationProtocol:
+		return v.String()
+	}
+	return nameUnknown
+}
+
+// StringConst returns the named group's name, "GREASE" or "unknown".
+func (v NamedGroup) StringConst() string {
+	switch v {
+	case GroupSECP256R1, GroupSECP384R1, GroupSECP521R1,
+		GroupX25519, GroupX448, GroupX25519MLKEM768:
+		return v.String()
+	}
+	if IsGREASE(uint16(v)) {
+		return nameGREASE
+	}
+	return nameUnknown
+}
+
+// StringConst returns the signature scheme's name, "GREASE" or "unknown".
+func (v SignatureScheme) StringConst() string {
+	switch v {
+	case SigRSAPKCS1SHA256, SigRSAPKCS1SHA384, SigRSAPKCS1SHA512,
+		SigECDSAP256SHA256, SigECDSAP384SHA384, SigECDSAP521SHA512,
+		SigRSAPSSRSAESHA256, SigRSAPSSRSAESHA384, SigRSAPSSRSAESHA512,
+		SigEd25519, SigRSAPSSPSSSHA256:
+		return v.String()
+	}
+	if IsGREASE(uint16(v)) {
+		return nameGREASE
+	}
+	return nameUnknown
+}
+
+// StringConst returns the cipher suite's name, "GREASE" or "unknown".
+// Every TLS 1.2 suite a browser still offers is undefined here: this package
+// implements TLS 1.3 only.
+func (v CipherSuite) StringConst() string {
+	switch v {
+	case SuiteAES128GCMSHA256, SuiteAES256GCMSHA384, SuiteChaCha20Poly1305SHA256,
+		SuiteAES128CCMSHA256, SuiteAES128CCM8SHA256:
+		return v.String()
+	}
+	if IsGREASE(uint16(v)) {
+		return nameGREASE
+	}
+	return nameUnknown
+}