FIX #68 #28

go.mod

@@ -5,10 +5,12 @@ go 1.25.0
 require (
 	github.com/coder/websocket v1.8.15
 	github.com/iniwex5/quectel-qmi-go v0.6.0
+	github.com/warthog618/sms v0.3.0
 	go.bug.st/serial v1.6.4
 	golang.org/x/crypto v0.52.0
 	golang.org/x/sys v0.47.0
 	golang.org/x/term v0.43.0
+	golang.org/x/text v0.41.0
 	howett.net/plist v1.0.1
 	modernc.org/sqlite v1.38.2
 )
@@ -21,7 +23,6 @@ require (
 	github.com/ncruces/go-strftime v0.1.9 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/stretchr/testify v1.10.0 // indirect
-	github.com/warthog618/sms v0.3.0 // indirect
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
 	modernc.org/libc v1.66.3 // indirect
 	modernc.org/mathutil v1.7.1 // indirect

go.sum

@@ -46,6 +46,8 @@ golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
 golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.43.0 h1:S4RLU2sB31O/NCl+zFN9Aru9A/Cq2aqKpTZJ6B+DwT4=
 golang.org/x/term v0.43.0/go.mod h1:lrhlHNdQJHO+1qVYiHfFKVuVioJIheAc3fBSMFYEIsk=
+golang.org/x/text v0.41.0 h1:vz/seA0lnX87Othu2f/0L24RcgrXD9/YFTSuGjj3rH8=
+golang.org/x/text v0.41.0/go.mod h1:jvf1O8ajNzZqhSrQBPbutR/EB83Cc0CFrezNQIwbb5M=
 golang.org/x/tools v0.34.0 h1:qIpSLOxeCYGg9TrcJokLBG4KFA6d795g0xkBkiESGlo=
 golang.org/x/tools v0.34.0/go.mod h1:pAP9OwEaY1CAW3HOmg3hLZC5Z0CCmzjAF2UQMSqNARg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/device/sms_pdu.go

@@ -8,7 +8,13 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 	"unicode/utf16"
+	"unicode/utf8"
+
+	"github.com/warthog618/sms/encoding/gsm7"
+	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/transform"
 )
 
 var gsm7DefaultAlphabet = [128]rune{
@@ -770,14 +776,19 @@ func readTPAddress(cursor *pduCursor) (string, error) {
 	var septetCount int
 	if toa&0x70 == 0x50 {
 		// 3GPP TS 23.040 §9.1.2.5: For alphanumeric addresses, the length field
-		// indicates the number of useful semi-octets (i.e. characters * 7 / 4, rounded up).
-		// The number of characters is (length * 4) / 7 and byte count is (length + 1) / 2.
-		// However, some non-standard sources specify length as the direct count of septets
-		// (e.g. length=4 for 4 chars, which needs 4 bytes instead of (4+1)/2=2 bytes).
-		if length >= 7 {
-			byteCount = (int(length) + 1) / 2
-			septetCount = int(length) * 4 / 7
-		} else {
+		// is a count of useful semi-octets, not a character count. In particular,
+		// a three-character sender such as "OKX" has length 6. Treating every
+		// short length as a septet count consumes PID/DCS bytes as part of the
+		// address and shifts the entire TPDU, producing plausible-looking GSM-7
+		// garbage instead of the message body.
+		byteCount = (int(length) + 1) / 2
+		septetCount = int(length) * 4 / 7
+
+		// A few legacy/non-standard sources do put the character count in this
+		// field. Retain compatibility only when the standard-sized value cannot
+		// be a valid zero-padded GSM-7 address; do not guess based on its length.
+		if byteCount == 0 || cursor.index+byteCount > len(cursor.data) ||
+			!hasZeroGSM7Padding(cursor.data[cursor.index:cursor.index+byteCount], septetCount) {
 			byteCount = (int(length)*7 + 7) / 8
 			septetCount = int(length)
 		}
@@ -798,6 +809,18 @@ func readTPAddress(cursor *pduCursor) (string, error) {
 	return decodeNumericAddress(value, int(length), toa), nil
 }
 
+func hasZeroGSM7Padding(data []byte, septetCount int) bool {
+	if septetCount <= 0 || septetCount*7 > len(data)*8 {
+		return false
+	}
+	for bit := septetCount * 7; bit < len(data)*8; bit++ {
+		if data[bit/8]&(byte(1)<<uint(bit%8)) != 0 {
+			return false
+		}
+	}
+	return true
+}
+
 func decodeNumericAddress(value []byte, digits int, toa byte) string {
 	var result strings.Builder
 	if toa&0x70 == 0x10 {
@@ -825,9 +848,9 @@ func decodeUserData(
 	udl int,
 	message *SMSMessage,
 ) error {
-	alphabet := dcs & 0x0c
+	alphabet := decodeSMSAlphabet(dcs)
 	expectedBytes := udl
-	if alphabet == 0 {
+	if alphabet == smsAlphabetGSM7 {
 		expectedBytes = (udl*7 + 7) / 8
 	}
 	if expectedBytes > len(data) {
@@ -848,8 +871,12 @@ func decodeUserData(
 		message.Concat = parseConcatHeader(data[1:headerBytes])
 	}
 
+	var header []byte
+	if headerBytes > 0 {
+		header = data[1:headerBytes]
+	}
 	switch alphabet {
-	case 0:
+	case smsAlphabetGSM7:
 		message.Encoding = SMSEncodingGSM7PDU
 		headerSeptets := 0
 		if headerBytes > 0 {
@@ -860,33 +887,228 @@ func decodeUserData(
 		if err != nil {
 			return err
 		}
-		text, err := decodeGSM7(septets)
+		text, err := decodeGSM7WithHeader(septets, header)
 		message.Text = text
 		return err
-	case 8:
+	case smsAlphabetUCS2:
 		message.Encoding = SMSEncodingUCS2PDU
 		payload := data[headerBytes:]
-		if len(payload)%2 != 0 {
-			return errors.New("UCS2 SMS has an odd byte count")
+		text, ok := decodeUTF16Bytes(payload)
+		if ok {
+			message.Text = text
+			return nil
 		}
-		units := make([]uint16, 0, len(payload)/2)
-		for index := 0; index < len(payload); index += 2 {
-			units = append(units, uint16(payload[index])<<8|uint16(payload[index+1]))
+		// Some gateways label UTF-8 or a local 8-bit character set as UCS-2.
+		// Only accept a fallback when it is unambiguously readable text.
+		if text, encoding, detected := decodeTextBytes(payload, header); detected {
+			message.Text = text
+			message.Encoding = encoding
+			return nil
 		}
-		message.Text = string(utf16.Decode(units))
-		return nil
+		return errors.New("UCS2 SMS has invalid UTF-16 data")
 	default:
-		// 8-bit (binary) user data has no portable text representation, so the
-		// raw payload bytes are rendered as uppercase hexadecimal after the user
-		// data header is stripped. This keeps the bubble non-empty and gives a
-		// faithful rendering of the delivered content rather than a blank "".
-		message.Encoding = SMSEncoding8BitPDU
 		payload := data[headerBytes:]
+		if text, encoding, detected := decodeTextBytes(payload, header); detected {
+			message.Text = text
+			message.Encoding = encoding
+			return nil
+		}
+		// Port-addressed or non-text 8-bit data remains hexadecimal, preserving
+		// binary SMS (WAP push, provisioning, SIM data) without lossy guessing.
+		message.Encoding = SMSEncoding8BitPDU
 		message.Text = strings.ToUpper(hex.EncodeToString(payload))
 		return nil
 	}
 }
 
+type smsAlphabet byte
+
+const (
+	smsAlphabetGSM7 smsAlphabet = iota
+	smsAlphabet8Bit
+	smsAlphabetUCS2
+	smsAlphabetUnknown
+)
+
+// decodeSMSAlphabet applies the complete 3GPP TS 23.038 DCS grouping rules.
+// A plain dcs&0x0c check is incorrect for message-waiting groups Cx/Dx/Ex and
+// reserved coding groups, and can silently select the wrong decoder.
+func decodeSMSAlphabet(dcs byte) smsAlphabet {
+	switch {
+	case dcs&0x80 == 0:
+		if dcs&0x20 != 0 { // GSM compression is not safely decodable here.
+			return smsAlphabetUnknown
+		}
+		switch (dcs >> 2) & 0x03 {
+		case 0:
+			return smsAlphabetGSM7
+		case 1:
+			return smsAlphabet8Bit
+		case 2:
+			return smsAlphabetUCS2
+		default:
+			return smsAlphabetUnknown
+		}
+	case dcs&0xe0 == 0xc0: // Cx and Dx message-waiting groups use GSM-7.
+		return smsAlphabetGSM7
+	case dcs&0xf0 == 0xe0: // Ex message-waiting group uses UCS-2.
+		return smsAlphabetUCS2
+	case dcs&0xf0 == 0xf0:
+		if dcs&0x04 != 0 {
+			return smsAlphabet8Bit
+		}
+		return smsAlphabetGSM7
+	default:
+		return smsAlphabetUnknown
+	}
+}
+
+func decodeGSM7WithHeader(septets, header []byte) (string, error) {
+	locking, hasLocking := userDataHeaderLanguage(header, 0x25)
+	shift, hasShift := userDataHeaderLanguage(header, 0x24)
+	if !hasLocking && !hasShift {
+		return decodeGSM7(septets)
+	}
+	options := make([]gsm7.DecoderOption, 0, 2)
+	if hasLocking {
+		options = append(options, gsm7.WithCharset(locking))
+	}
+	if hasShift {
+		options = append(options, gsm7.WithExtCharset(shift))
+	}
+	decoded, err := gsm7.Decode(septets, options...)
+	return string(decoded), err
+}
+
+func userDataHeaderLanguage(header []byte, identifier byte) (int, bool) {
+	for index := 0; index+1 < len(header); {
+		id := header[index]
+		length := int(header[index+1])
+		index += 2
+		if index+length > len(header) {
+			return 0, false
+		}
+		if id == identifier && length == 1 {
+			return int(header[index]), true
+		}
+		index += length
+	}
+	return 0, false
+}
+
+func decodeUTF16Bytes(payload []byte) (string, bool) {
+	if len(payload) == 0 {
+		return "", true
+	}
+	if len(payload)%2 != 0 {
+		return "", false
+	}
+	littleEndian := len(payload) >= 2 && payload[0] == 0xff && payload[1] == 0xfe
+	if (payload[0] == 0xfe && payload[1] == 0xff) || littleEndian {
+		payload = payload[2:]
+	}
+	units := make([]uint16, 0, len(payload)/2)
+	for index := 0; index < len(payload); index += 2 {
+		unit := uint16(payload[index])<<8 | uint16(payload[index+1])
+		if littleEndian {
+			unit = uint16(payload[index+1])<<8 | uint16(payload[index])
+		}
+		units = append(units, unit)
+	}
+	text := string(utf16.Decode(units))
+	return text, !strings.ContainsRune(text, unicode.ReplacementChar) && readableText(text)
+}
+
+func decodeTextBytes(payload, header []byte) (string, SMSEncoding, bool) {
+	if hasApplicationPortAddressing(header) || len(payload) == 0 {
+		return "", SMSEncoding8BitPDU, false
+	}
+	if len(payload) >= 2 && ((payload[0] == 0xfe && payload[1] == 0xff) ||
+		(payload[0] == 0xff && payload[1] == 0xfe)) {
+		if text, ok := decodeUTF16Bytes(payload); ok {
+			return text, SMSEncodingUCS2PDU, true
+		}
+	}
+	if utf8.Valid(payload) {
+		text := string(payload)
+		if readableText(text) {
+			return text, SMSEncodingUTF8PDU, true
+		}
+	}
+	if containsNonASCII(payload) {
+		decoded, _, err := transform.Bytes(simplifiedchinese.GB18030.NewDecoder(), payload)
+		text := string(decoded)
+		if err == nil && strings.ContainsFunc(text, func(character rune) bool {
+			return unicode.Is(unicode.Han, character)
+		}) && readableText(text) {
+			return text, SMSEncodingGB18030, true
+		}
+	}
+	if text, ok := decodeLatin1Text(payload); ok {
+		return text, SMSEncodingLatin1, true
+	}
+	return "", SMSEncoding8BitPDU, false
+}
+
+func readableText(text string) bool {
+	if text == "" {
+		return true
+	}
+	printable, total := 0, 0
+	for _, character := range text {
+		total++
+		if unicode.IsPrint(character) || character == '\n' || character == '\r' || character == '\t' {
+			printable++
+		}
+	}
+	return printable*100 >= total*90
+}
+
+func containsNonASCII(data []byte) bool {
+	for _, value := range data {
+		if value >= utf8.RuneSelf {
+			return true
+		}
+	}
+	return false
+}
+
+func decodeLatin1Text(payload []byte) (string, bool) {
+	characters := make([]rune, 0, len(payload))
+	ascii := 0
+	for _, value := range payload {
+		switch {
+		case value == '\n' || value == '\r' || value == '\t' || value >= 0x20 && value <= 0x7e:
+			ascii++
+		case value >= 0xa0:
+		default:
+			return "", false
+		}
+		characters = append(characters, rune(value))
+	}
+	if ascii == 0 || ascii*2 < len(payload) {
+		return "", false
+	}
+	text := string(characters)
+	return text, readableText(text)
+}
+
+func hasApplicationPortAddressing(header []byte) bool {
+	for index := 0; index+1 < len(header); {
+		identifier := header[index]
+		length := int(header[index+1])
+		index += 2
+		if index+length > len(header) {
+			return true
+		}
+		if (identifier == 0x04 && length == 2) || (identifier == 0x05 && length == 4) {
+			return true
+		}
+		index += length
+	}
+	return false
+}
+
 func parseConcatHeader(header []byte) *SMSConcatInfo {
 	for index := 0; index+1 < len(header); {
 		identifier := header[index]

internal/device/sms_pdu_test.go

@@ -1,6 +1,7 @@
 package device
 
 import (
+	"encoding/hex"
 	"errors"
 	"strings"
 	"testing"
@@ -323,6 +324,35 @@ func TestDecodeDeliverPDUWithAlphanumericSender(t *testing.T) {
 	}
 }
 
+func TestDecodeDeliverPDUWithShortStandardAlphanumericSender(t *testing.T) {
+	// TP-OA length is expressed in useful semi-octets. The three-character
+	// sender "OKX" therefore has length 6, even though it contains 3 septets.
+	// A previous short-address heuristic interpreted 6 as the character count
+	// and swallowed PID, DCS, and timestamp bytes into the sender address.
+	text := "Your OKX verification code is: 123456"
+	textSeptets, ok := encodeGSM7(text)
+	if !ok {
+		t.Fatal("test text is not GSM-7 encodable")
+	}
+	pdu := []byte{0x00, 0x04, 0x06, 0xd0}
+	pdu = append(pdu, packSeptets([]byte{'O', 'K', 'X'}, 0)...)
+	pdu = append(pdu,
+		0x00, 0x00, // PID and GSM-7 DCS.
+		0x62, 0x80, 0x20, 0x91, 0x40, 0x95, 0x00, // 2026-08-02 19:04:59 UTC.
+		byte(len(textSeptets)),
+	)
+	pdu = append(pdu, packSeptets(textSeptets, 0)...)
+
+	message, err := decodeSMSPDU(hex.EncodeToString(pdu))
+	if err != nil {
+		t.Fatalf("decode short alphanumeric sender: %v", err)
+	}
+	if message.From != "OKX" || message.Text != text ||
+		message.Encoding != SMSEncodingGSM7PDU || message.DataCodingScheme != 0 {
+		t.Fatalf("message = %#v", message)
+	}
+}
+
 func TestDecode8BitPDUShowsHexPayload(t *testing.T) {
 	// SMS-DELIVER with no SMSC, from +12345, DCS=0xF5 (8-bit data,
 	// alphabet bits 0x0c), UDL=3. User data bytes are 0xAA 0xBB 0xCC.
@@ -340,3 +370,87 @@ func TestDecode8BitPDUShowsHexPayload(t *testing.T) {
 		t.Fatalf("8-bit message = %#v", message)
 	}
 }
+
+func TestDecodeUserDataUnderstandsDCSGroups(t *testing.T) {
+	septets, ok := encodeGSM7("HELLO")
+	if !ok {
+		t.Fatal("encode GSM-7 test text")
+	}
+	packed := packSeptets(septets, 0)
+	for _, dcs := range []byte{0x00, 0xc8, 0xd0, 0xf0} {
+		message := SMSMessage{}
+		if err := decodeUserData(packed, 0, dcs, len(septets), &message); err != nil {
+			t.Fatalf("decode DCS 0x%02X: %v", dcs, err)
+		}
+		if message.Text != "HELLO" || message.Encoding != SMSEncodingGSM7PDU {
+			t.Fatalf("DCS 0x%02X message = %#v", dcs, message)
+		}
+	}
+
+	ucs2 := []byte{0x4f, 0x60, 0x59, 0x7d}
+	for _, dcs := range []byte{0x08, 0xe0} {
+		message := SMSMessage{}
+		if err := decodeUserData(ucs2, 0, dcs, len(ucs2), &message); err != nil {
+			t.Fatalf("decode DCS 0x%02X: %v", dcs, err)
+		}
+		if message.Text != "你好" || message.Encoding != SMSEncodingUCS2PDU {
+			t.Fatalf("DCS 0x%02X message = %#v", dcs, message)
+		}
+	}
+}
+
+func TestDecodeGSM7NationalLanguageTables(t *testing.T) {
+	// National language locking shift IEI 0x25, Turkish table 1. In that
+	// locking table septet 0x07 is the dotless i (ı), rather than default ì.
+	header := []byte{0x03, 0x25, 0x01, 0x01}
+	headerSeptets := (len(header)*8 + 6) / 7
+	data := packSeptets([]byte{0x07}, headerSeptets*7)
+	copy(data, header)
+
+	message := SMSMessage{}
+	if err := decodeUserData(data, 0x40, 0x00, headerSeptets+1, &message); err != nil {
+		t.Fatalf("decode Turkish locking table: %v", err)
+	}
+	if message.Text != "ı" || message.Encoding != SMSEncodingGSM7PDU {
+		t.Fatalf("message = %#v", message)
+	}
+}
+
+func TestDecode8BitTextEncodingsAndPreservesBinary(t *testing.T) {
+	tests := []struct {
+		name     string
+		payload  []byte
+		wantText string
+		encoding SMSEncoding
+	}{
+		{name: "UTF-8", payload: []byte("验证码 123456"), wantText: "验证码 123456", encoding: SMSEncodingUTF8PDU},
+		{name: "GB18030", payload: []byte{0xd1, 0xe9, 0xd6, 0xa4, 0xc2, 0xeb}, wantText: "验证码", encoding: SMSEncodingGB18030},
+		{name: "Latin-1", payload: []byte{'C', 'a', 'f', 0xe9}, wantText: "Café", encoding: SMSEncodingLatin1},
+		{name: "binary", payload: []byte{0xaa, 0xbb, 0xcc}, wantText: "AABBCC", encoding: SMSEncoding8BitPDU},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			message := SMSMessage{}
+			if err := decodeUserData(test.payload, 0, 0x04, len(test.payload), &message); err != nil {
+				t.Fatalf("decode: %v", err)
+			}
+			if message.Text != test.wantText || message.Encoding != test.encoding {
+				t.Fatalf("message = %#v", message)
+			}
+		})
+	}
+}
+
+func TestDecodePortAddressed8BitSMSRemainsBinary(t *testing.T) {
+	header := []byte{0x04, 0x04, 0x02, 0x0b, 0x84}
+	data := append(append([]byte(nil), header...), []byte("plain-looking payload")...)
+	message := SMSMessage{}
+	if err := decodeUserData(data, 0x40, 0x04, len(data), &message); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	payload := data[len(header):]
+	if message.Text != strings.ToUpper(hex.EncodeToString(payload)) ||
+		message.Encoding != SMSEncoding8BitPDU {
+		t.Fatalf("message = %#v", message)
+	}
+}

internal/device/types.go

@@ -146,6 +146,9 @@ const (
 	SMSEncodingGSM7Text SMSEncoding = "gsm7_text"
 	SMSEncodingGSM7PDU  SMSEncoding = "gsm7_pdu"
 	SMSEncodingUCS2PDU  SMSEncoding = "ucs2_pdu"
+	SMSEncodingUTF8PDU  SMSEncoding = "utf8_pdu"
+	SMSEncodingGB18030  SMSEncoding = "gb18030_pdu"
+	SMSEncodingLatin1   SMSEncoding = "latin1_pdu"
 	SMSEncoding8BitPDU  SMSEncoding = "8bit_pdu"
 	SMSEncodingUnknown  SMSEncoding = "unknown"
 )

internal/vowifi/carrier_ipcc.go

@@ -662,11 +662,9 @@ func inspectIgnoredCarrierFields(plists []ipccPlist, warnings *ipccWarningSet) {
 			case key == "media" && strings.Contains(strings.ToLower(strings.Join(keyPath, ".")), "imsconfig"):
 				warnings.add("device_media_overrides_ignored", "device-family media and codec overrides require hardware validation and were not imported", fullPath)
 			case key == "countryoforiginationformat":
-				warnings.add(
-					"country_of_origination_format_not_imported",
-					"CountryOfOriginationFormat was not imported because VoCat has no trusted runtime country source; a P-Access-Network-Info value must not be fabricated",
-					fullPath,
-				)
+				// PANI is access/session metadata, not a carrier location constant.
+				// The IMS runtime provides one globally and consistently across
+				// REGISTER, MESSAGE, RP-ACK and dialogs, so no profile field is needed.
 			case strings.Contains(key, "emergency") || strings.Contains(key, "e911"):
 				warnings.add("emergency_settings_ignored", "emergency-service settings are never imported", fullPath)
 			}

internal/vowifi/carrier_ipcc_test.go

@@ -82,7 +82,6 @@ func TestImportCarrierIPCCConvertsBinaryAndXMLPlistsSafely(t *testing.T) {
 		"entitlement_bypass_ignored",
 		"apn_settings_ignored",
 		"device_media_overrides_ignored",
-		"country_of_origination_format_not_imported",
 		"emergency_settings_ignored",
 	} {
 		if !hasIPCCWarning(result.Warnings, code) {

internal/vowifi/ims/call_runtime.go

@@ -799,16 +799,10 @@ func (session *Session) callOriginatingIdentitiesLocked(profile vowifi.CarrierPr
 }
 
 func (session *Session) pAccessNetworkInfo() string {
-	profile := vowifi.ResolveCarrierProfile(session.request.Identity)
-	node := strings.TrimSpace(profile.PANINode)
-	if node == "" {
-		node = "000000000000"
+	if session.paniResolved {
+		return ueProvidedPANI(session.pani)
 	}
-	value := "IEEE-802.11;i-wlan-node-id=" + node
-	if country := strings.ToUpper(strings.TrimSpace(profile.PANICountry)); country != "" {
-		value += ";country=" + country
-	}
-	return value + ";network-provided"
+	return sessionPAccessNetworkInfo(session.instanceID)
 }
 
 func (session *Session) callUserAgent() string {

internal/vowifi/ims/call_runtime_test.go

@@ -229,7 +229,7 @@ func TestOutgoingLocalNumberUsesIMSPhoneContextAndMMTelHeaders(t *testing.T) {
 		"P-Preferred-Identity: <tel:+447700900123>\r\n",
 		"P-Preferred-Service: " + mmtelServiceURN + "\r\n",
 		`Accept-Contact: *;+g.3gpp.icsi-ref="` + mmtelFeatureTag + `"` + "\r\n",
-		"P-Access-Network-Info: IEEE-802.11;i-wlan-node-id=000000000000;network-provided\r\n",
+		"P-Access-Network-Info: " + sessionPAccessNetworkInfo(session.instanceID) + "\r\n",
 		"User-Agent: VoCat Test\r\n",
 		"Accept: application/sdp\r\n",
 	} {

internal/vowifi/ims/provider.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"context"
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/base64"
 	"encoding/hex"
 	"errors"
@@ -594,6 +595,8 @@ type Session struct {
 	callID             string
 	fromTag            string
 	instanceID         string
+	pani               string
+	paniResolved       bool
 	cseq               uint32
 	auth               *authenticationState
 	securityProposal   securityProposal
@@ -658,6 +661,8 @@ func newSession(
 		callID:             callToken + "@" + addressHost(connection.LocalAddr()),
 		fromTag:            fromTag,
 		instanceID:         "urn:uuid:" + instanceID,
+		pani:               resolveSessionPAccessNetworkInfo(request.Identity, "urn:uuid:"+instanceID),
+		paniResolved:       true,
 		cseq:               1,
 		refreshContext:     refreshContext,
 		refreshCancel:      refreshCancel,
@@ -997,11 +1002,10 @@ func (session *Session) buildRegister(
 	if value := strings.TrimSpace(registerOptions.PVisitedNetworkID); value != "" {
 		lines = append(lines, `P-Visited-Network-ID: "`+value+`"`)
 	}
-	// PANI carries access/location information and must not be fabricated.
-	// In particular, "network-provided" identifies a value inserted by a
-	// trusted network proxy, not one generated by this UE.  Send the header
-	// only when a carrier profile explicitly supplies a reviewed value.
-	if pani := optionalRegisterHeader(registerOptions.PAccessNetworkInfo); pani != "" {
+	// PANI describes this UE's access and is stable for the complete IMS
+	// session. The same UE-provided value is used by REGISTER, MESSAGE,
+	// RP-ACK and dialog requests; it never claims to be network-provided.
+	if pani := session.pAccessNetworkInfo(); pani != "" {
 		lines = append(lines, "P-Access-Network-Info: "+pani)
 	}
 	if value := strings.TrimSpace(registerOptions.CellularNetworkInfo); value != "" {
@@ -1045,13 +1049,6 @@ func (session *Session) buildRegister(
 	return []byte(strings.Join(lines, "\r\n")), nil
 }
 
-func optionalRegisterHeader(value *string) string {
-	if value == nil {
-		return ""
-	}
-	return strings.TrimSpace(*value)
-}
-
 func (session *Session) buildContact(contactAddress string, registerOptions vowifi.IMSRegisterOptions) string {
 	base := fmt.Sprintf("<sip:%s@%s;transport=%s>", session.identity.user, contactAddress, session.transport)
 	instanceID := session.instanceID
@@ -1079,6 +1076,58 @@ func (session *Session) buildContact(contactAddress string, registerOptions vowi
 	}
 }
 
+// sessionPAccessNetworkInfo creates a syntactically valid, locally
+// administered unicast WLAN node identifier from the already-random SIP
+// instance ID. It discloses neither a real BSSID nor subscriber identity, but
+// remains stable for every transaction belonging to this IMS registration.
+func sessionPAccessNetworkInfo(instanceID string) string {
+	instanceID = strings.TrimSpace(instanceID)
+	if instanceID == "" {
+		return ""
+	}
+	digest := sha256.Sum256([]byte(instanceID))
+	digest[0] = (digest[0] | 0x02) & 0xfe // locally administered, unicast
+	return "IEEE-802.11;i-wlan-node-id=" + hex.EncodeToString(digest[:6])
+}
+
+// resolveSessionPAccessNetworkInfo freezes the selected value when the IMS
+// session is created. This prevents a carrier-profile reload from changing
+// access identity between REGISTER, SMS MESSAGE and its RP-ACK.
+func resolveSessionPAccessNetworkInfo(identity vowifi.SIMIdentity, instanceID string) string {
+	profile := vowifi.ResolveCarrierProfile(identity)
+	if configured := profile.IMSRegisterOptions.PAccessNetworkInfo; configured != nil {
+		return ueProvidedPANI(*configured)
+	}
+
+	node := strings.ToLower(strings.TrimSpace(profile.PANINode))
+	if decoded, err := hex.DecodeString(node); err != nil || len(decoded) != 6 {
+		node = strings.TrimPrefix(sessionPAccessNetworkInfo(instanceID), "IEEE-802.11;i-wlan-node-id=")
+	}
+	if node == "" {
+		return ""
+	}
+	value := "IEEE-802.11;i-wlan-node-id=" + node
+	if country := strings.ToUpper(strings.TrimSpace(profile.PANICountry)); country != "" {
+		value += ";country=" + country
+	}
+	return value
+}
+
+// ueProvidedPANI removes the network-provided marker from a profile override.
+// RFC 7315 reserves that marker for a trusted proxy; a UE must not assert it.
+func ueProvidedPANI(value string) string {
+	parts := strings.Split(strings.TrimSpace(value), ";")
+	filtered := parts[:0]
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "" || strings.EqualFold(part, "network-provided") {
+			continue
+		}
+		filtered = append(filtered, part)
+	}
+	return strings.Join(filtered, ";")
+}
+
 func (session *Session) exchange(ctx context.Context, request []byte, cseq uint32) (*sipResponse, error) {
 	if err := ctx.Err(); err != nil {
 		return nil, err

internal/vowifi/ims/provider_test.go

@@ -3,6 +3,7 @@ package ims
 import (
 	"context"
 	"encoding/base64"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
@@ -361,6 +362,7 @@ func TestRefreshFailureRevokesRegistrationEvidence(t *testing.T) {
 
 func serveRegistration(listener *net.UDPConn, nonce string, confirmSMS bool) error {
 	var callID string
+	var pani string
 	for step := 0; step < 4; step++ {
 		packet := make([]byte, 65535)
 		count, remote, err := listener.ReadFromUDP(packet)
@@ -377,7 +379,6 @@ func serveRegistration(listener *net.UDPConn, nonce string, confirmSMS bool) err
 		for _, forbidden := range []string{
 			"p-visited-network-id",
 			"p-preferred-identity",
-			"p-access-network-info",
 		} {
 			if headers[forbidden] != "" {
 				return fmt.Errorf(
@@ -387,6 +388,15 @@ func serveRegistration(listener *net.UDPConn, nonce string, confirmSMS bool) err
 				)
 			}
 		}
+		currentPANI := headers["p-access-network-info"]
+		if err := validateTestPANI(currentPANI); err != nil {
+			return fmt.Errorf("REGISTER PANI: %w", err)
+		}
+		if step == 0 {
+			pani = currentPANI
+		} else if currentPANI != pani {
+			return fmt.Errorf("REGISTER PANI changed from %q to %q", pani, currentPANI)
+		}
 		if !strings.Contains(headers["allow"], "MESSAGE") ||
 			!strings.Contains(string(packet[:count]), "Accept-Contact: *;+g.3gpp.smsip") {
 			return fmt.Errorf("REGISTER omitted SMS-over-IMS capability: Allow=%q", headers["allow"])
@@ -495,24 +505,43 @@ func serveRegistration(listener *net.UDPConn, nonce string, confirmSMS bool) err
 	return nil
 }
 
-func TestOptionalRegisterHeaderRequiresExplicitNonemptyValue(t *testing.T) {
-	explicit := "  IEEE-802.11;i-wlan-node-id=aabbccddeeff  "
-	empty := "  "
-	for _, test := range []struct {
-		name  string
-		value *string
-		want  string
-	}{
-		{name: "unspecified", value: nil, want: ""},
-		{name: "explicit omission", value: &empty, want: ""},
-		{name: "explicit value", value: &explicit, want: "IEEE-802.11;i-wlan-node-id=aabbccddeeff"},
-	} {
-		t.Run(test.name, func(t *testing.T) {
-			if got := optionalRegisterHeader(test.value); got != test.want {
-				t.Fatalf("optionalRegisterHeader() = %q, want %q", got, test.want)
-			}
-		})
+func TestSessionPAccessNetworkInfoIsStableAndUEProvided(t *testing.T) {
+	instanceID := "urn:uuid:00000000-0000-4000-8000-000000000001"
+	first := sessionPAccessNetworkInfo(instanceID)
+	second := sessionPAccessNetworkInfo(instanceID)
+	if first != second {
+		t.Fatalf("PANI changed for one SIP instance: %q != %q", first, second)
 	}
+	if err := validateTestPANI(first); err != nil {
+		t.Fatal(err)
+	}
+	if got := ueProvidedPANI(" IEEE-802.11;i-wlan-node-id=aabbccddeeff;network-provided "); got != "IEEE-802.11;i-wlan-node-id=aabbccddeeff" {
+		t.Fatalf("ueProvidedPANI() = %q", got)
+	}
+	if got := ueProvidedPANI("network-provided"); got != "" {
+		t.Fatalf("marker-only PANI = %q, want empty", got)
+	}
+	if got := (&Session{paniResolved: true}).pAccessNetworkInfo(); got != "" {
+		t.Fatalf("explicitly omitted session PANI = %q, want empty", got)
+	}
+}
+
+func validateTestPANI(value string) error {
+	const prefix = "IEEE-802.11;i-wlan-node-id="
+	if !strings.HasPrefix(value, prefix) {
+		return fmt.Errorf("value %q does not start with %q", value, prefix)
+	}
+	if strings.Contains(strings.ToLower(value), "network-provided") {
+		return fmt.Errorf("UE PANI incorrectly claims network-provided provenance: %q", value)
+	}
+	node, err := hex.DecodeString(strings.TrimPrefix(value, prefix))
+	if err != nil || len(node) != 6 {
+		return fmt.Errorf("i-wlan-node-id must be 12 hexadecimal digits: %q", value)
+	}
+	if node[0]&0x03 != 0x02 {
+		return fmt.Errorf("i-wlan-node-id must be a locally administered unicast identifier: %q", value)
+	}
+	return nil
 }
 
 func serveRefreshFailure(listener *net.UDPConn, nonce string) error {

internal/vowifi/ims/sms_runtime.go

@@ -56,6 +56,7 @@ type ReceivedSMS struct {
 	RawTPDU                string
 	DecodeError            string
 }
+
 // ReceivedSMSStatus is network delivery evidence for one submitted SMS part.
 type ReceivedSMSStatus struct {
 	DeviceID               string
@@ -1165,6 +1166,9 @@ func (session *Session) sendSIPMessageWith(
 		fmt.Sprintf("CSeq: %d MESSAGE", cseq),
 		"P-Preferred-Identity: <"+session.identity.public+">",
 	)
+	if pani := session.pAccessNetworkInfo(); pani != "" {
+		lines = append(lines, "P-Access-Network-Info: "+pani)
+	}
 	if acceptContactTag != "" {
 		lines = append(lines, "Accept-Contact: *;+g.3gpp."+acceptContactTag)
 	}

internal/vowifi/ims/sms_runtime_test.go

@@ -352,6 +352,10 @@ func serveInboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<- s
 	if err != nil {
 		return err
 	}
+	registerPANI := headers["p-access-network-info"]
+	if err := validateTestPANI(registerPANI); err != nil {
+		return fmt.Errorf("initial REGISTER PANI: %w", err)
+	}
 	callID := headers["call-id"]
 	if _, err = listener.WriteToUDP(testResponse(401, "Unauthorized", callID, headers["cseq"], []string{
 		`WWW-Authenticate: Digest realm="ims.mnc001.mcc001.3gppnetwork.org", nonce="` + nonce + `", algorithm=AKAv1-MD5, qop="auth"`,
@@ -366,6 +370,9 @@ func serveInboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<- s
 	if err != nil {
 		return err
 	}
+	if headers["p-access-network-info"] != registerPANI {
+		return errors.New("authenticated REGISTER changed PANI")
+	}
 	if _, err = listener.WriteToUDP(testResponse(200, "OK", callID, headers["cseq"], []string{
 		"Contact: " + headers["contact"] + ";expires=600",
 	}), remote); err != nil {
@@ -433,6 +440,9 @@ func serveInboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<- s
 		len(report.Request.Body) != 2 || report.Request.Body[0] != 0x02 || report.Request.Body[1] != 0x2a {
 		return fmt.Errorf("unexpected delivery report %#v", report.Request)
 	}
+	if report.Request.value("P-Access-Network-Info") != registerPANI {
+		return errors.New("inbound SMS RP-ACK did not reuse REGISTER PANI")
+	}
 	if _, err = listener.WriteToUDP(testResponse(200, "OK", report.Request.value("Call-ID"), report.Request.value("CSeq"), nil), remote); err != nil {
 		return err
 	}
@@ -449,6 +459,9 @@ func serveInboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<- s
 	if headers["expires"] != "0" {
 		return errors.New("expected deregistration")
 	}
+	if headers["p-access-network-info"] != registerPANI {
+		return errors.New("deregistration changed PANI")
+	}
 	_, err = listener.WriteToUDP(testResponse(200, "OK", callID, headers["cseq"], nil), remote)
 	return err
 }
@@ -463,6 +476,10 @@ func serveOutboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<-
 	if err != nil {
 		return err
 	}
+	registerPANI := headers["p-access-network-info"]
+	if err := validateTestPANI(registerPANI); err != nil {
+		return fmt.Errorf("initial REGISTER PANI: %w", err)
+	}
 	registerCallID := headers["call-id"]
 	if _, err = listener.WriteToUDP(testResponse(401, "Unauthorized", registerCallID, headers["cseq"], []string{
 		`WWW-Authenticate: Digest realm="ims.mnc001.mcc001.3gppnetwork.org", nonce="` + nonce + `", algorithm=AKAv1-MD5, qop="auth"`,
@@ -477,6 +494,9 @@ func serveOutboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<-
 	if err != nil {
 		return err
 	}
+	if headers["p-access-network-info"] != registerPANI {
+		return errors.New("authenticated REGISTER changed PANI")
+	}
 	if _, err = listener.WriteToUDP(testResponse(200, "OK", registerCallID, headers["cseq"], []string{
 		"Contact: " + headers["contact"] + ";expires=600",
 	}), remote); err != nil {
@@ -508,6 +528,9 @@ func serveOutboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<-
 		message.Request.value("Allow") != "MESSAGE" {
 		return fmt.Errorf("unexpected outbound MESSAGE %#v", message.Request)
 	}
+	if message.Request.value("P-Access-Network-Info") != registerPANI {
+		return errors.New("outbound SMS MESSAGE did not reuse REGISTER PANI")
+	}
 	rpdu, err := parseRPDU(message.Request.Body)
 	if err != nil || rpdu.messageType != 0 || len(rpdu.tpdu) != 0 {
 		// parseRPDU intentionally decodes only network-to-MS RP-DATA; inspect
@@ -573,6 +596,9 @@ func serveOutboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<-
 		len(statusACK.Request.Body) != 2 || statusACK.Request.Body[0] != 0x02 || statusACK.Request.Body[1] != 0x2b {
 		return fmt.Errorf("unexpected status RP-ACK %#v (%v)", statusACK.Request, err)
 	}
+	if statusACK.Request.value("P-Access-Network-Info") != registerPANI {
+		return errors.New("status-report RP-ACK did not reuse REGISTER PANI")
+	}
 	if _, err = listener.WriteToUDP(testResponse(200, "OK", statusACK.Request.value("Call-ID"), statusACK.Request.value("CSeq"), nil), remote); err != nil {
 		return err
 	}
@@ -589,6 +615,9 @@ func serveOutboundSMS(listener *net.UDPConn, nonce string, readyForClose chan<-
 	if headers["expires"] != "0" {
 		return errors.New("expected deregistration")
 	}
+	if headers["p-access-network-info"] != registerPANI {
+		return errors.New("deregistration changed PANI")
+	}
 	_, err = listener.WriteToUDP(testResponse(200, "OK", registerCallID, headers["cseq"], nil), remote)
 	return err
 }