scp80: advance the counter after every send and persist it to the preset (v2.1.9)

The counter only advanced when a PoR came back with status por_ok, so
PoR-less sends kept reusing the same counter (the card rejects a repeated
counter for replay protection). It now advances on every successful send
(and shows "CNTR -> ..." in the result line), and the new value is written
into the selected card preset via spCntrSyncPreset(). Manually edited
counters are persisted too (the field's onchange). New spNextCntr() helper
with carry tests; service worker v146.

frontend/index.html

@@ -18,7 +18,7 @@
 <div class="max-w-7xl mx-auto px-6 py-2">
 
 	<div class="flex items-center justify-between mb-3">
-		<h1 class="text-2xl font-bold text-heading">OTAMan <span id="slogan" class="text-sm font-normal text-gray-500 dark:text-slate-400 ml-2" data-l10n="SIM OTA with a Human Face">SIM OTA with a Human Face</span> <span class="text-xs text-gray-400 dark:text-slate-500 ml-1">v2.1.8</span></h1>
+		<h1 class="text-2xl font-bold text-heading">OTAMan <span id="slogan" class="text-sm font-normal text-gray-500 dark:text-slate-400 ml-2" data-l10n="SIM OTA with a Human Face">SIM OTA with a Human Face</span> <span class="text-xs text-gray-400 dark:text-slate-500 ml-1">v2.1.9</span></h1>
 		<div class="flex items-center gap-4">
 			<span id="state-indicator" class="flex items-center select-none" style="cursor:default" title="Connecting...">
 				<span id="state-indicator-dot" class="text-xs text-gray-400" title="Connecting...">●</span>
@@ -512,7 +512,7 @@
 				<label class="block mb-1 text-sm font-medium text-gray-700 dark:text-slate-300">Counter (5 bytes)</label>
 				<div class="flex gap-1 items-center">
 					<button type="button" onclick="spCntrAdjust(-1)" class="px-2.5 py-2 border border-gray-300 dark:border-slate-600 text-sm rounded hover:bg-gray-200 dark:bg-slate-700 dark:hover:bg-slate-600">−</button>
-					<input id="sp-cntr" oninput="spInvalidate()" class="font-mono border border-gray-300 dark:border-slate-600 text-sm rounded px-3 py-1.5 flex-1 dark:bg-slate-800" placeholder="0000000001" maxlength="10" value="0000000001">
+					<input id="sp-cntr" oninput="spInvalidate()" onchange="spCntrSyncPreset()" class="font-mono border border-gray-300 dark:border-slate-600 text-sm rounded px-3 py-1.5 flex-1 dark:bg-slate-800" placeholder="0000000001" maxlength="10" value="0000000001">
 					<button type="button" onclick="spCntrAdjust(1)" class="px-2.5 py-2 border border-gray-300 dark:border-slate-600 text-sm rounded hover:bg-gray-200 dark:bg-slate-700 dark:hover:bg-slate-600">+</button>
 				</div>
 			</div>
@@ -4761,6 +4761,25 @@ async function pysimApdu() {
 	pysimRefresh();
 }
 
+function spNextCntr(value) {
+	// The OTA counter must strictly increase for every secured packet sent
+	// (replay protection): increment the 5-byte counter, carries included.
+	const v = (parseInt((value || '').replace(/[^0-9a-fA-F]/g, ''), 16) || 0) >>> 0;
+	return ((v + 1) >>> 0).toString(16).toUpperCase().padStart(10, '0').slice(-10);
+}
+
+function spCntrSyncPreset() {
+	// Persist the counter into the selected card preset: the OTA counter is
+	// part of the card's state and must survive reloads.
+	const sel = document.getElementById('sp-card-sel');
+	const idx = sel ? parseInt(sel.value, 10) : NaN;
+	if (isNaN(idx) || !cards[idx]) return false;
+	cards[idx].cntr = document.getElementById('sp-cntr').value;
+	cardsSave();
+	cardsRender();
+	return true;
+}
+
 function spParams() {
 	return {
 		spi1: document.getElementById('sp-spi1').value,
@@ -4835,22 +4854,16 @@ async function pysimSendOta() {
 				porStatusEl.textContent = 'PoR: ' + por.response_status;
 				porStatusEl.classList.remove('hidden', okPor ? 'text-red-600' : 'text-green-600');
 				porStatusEl.classList.add(okPor ? 'text-green-600' : 'text-red-600');
-				if (okPor) {
-					// packet was accepted and executed - advance the counter so the
-					// same secured packet can never be sent twice (v1.9.6)
-					const cntrEl = document.getElementById('sp-cntr');
-					cntrEl.value = ((parseInt(cntrEl.value, 16) || 0) + 1)
-						.toString(16).toUpperCase().padStart(10, '0').slice(-10);
-					document.getElementById('sp-result').value = '';
-					// keep the selected card preset in sync with the new counter (v1.9.8)
-					const selIdx = parseInt(document.getElementById('sp-card-sel').value, 10);
-					if (!isNaN(selIdx) && cards[selIdx]) {
-						cards[selIdx].cntr = cntrEl.value;
-						cardsSave();
-						cardsRender();
-					}
-				}
 			}
+			// The counter advances after every successful send, PoR or not: the
+			// card rejects a repeated counter (replay protection) and the same
+			// secured packet must never be sent twice (v1.9.6, revised 2.1.9).
+			const cntrEl = document.getElementById('sp-cntr');
+			cntrEl.value = spNextCntr(cntrEl.value);
+			msg += ' | CNTR -> ' + cntrEl.value;
+			document.getElementById('sp-result').value = '';
+			// keep the selected card preset in sync with the new counter (v1.9.8)
+			spCntrSyncPreset();
 			sendResultEl.textContent = msg;
 			if (por && por.raw) {
 				const rawLine = document.createElement('div');

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'otaman-v145';
+const CACHE = 'otaman-v146';
 const URLS = [
   'index.html',
   'help.html',

frontend/tests/sp.test.js

@@ -28,7 +28,7 @@ function extractFunc(src, name) {
 
 const FNS = ['hexToBytes', 'bytesToHex', 'des3Keys', 'des3EncryptBlock', 'des3CbcEncrypt',
 	'xorBytes', 'zeroPad', 'cbcMac', 'aesCbcEncrypt', 'aesShiftLeft1', 'aesCmacSubkeys',
-	'aesCmac', 'genSp'];
+	'aesCmac', 'genSp', 'spNextCntr'];
 let code = '';
 for (const f of FNS) code += extractFunc(html, f) + '\n';
 
@@ -217,3 +217,15 @@ test('AES rejects 8-byte key', () => {
 	});
 	assert.strictEqual(err, 'Error: AES KIc key must be 16, 24, or 32 bytes');
 });
+
+test('spNextCntr increments with carry', () => {
+	assert.strictEqual(spNextCntr('0000000001'), '0000000002');
+	assert.strictEqual(spNextCntr('00000000FF'), '0000000100');
+	assert.strictEqual(spNextCntr('000000FFFF'), '0000010000');
+	assert.strictEqual(spNextCntr('0000ABCDEF'), '0000ABCDF0');
+});
+
+test('spNextCntr tolerates lower case and separators', () => {
+	assert.strictEqual(spNextCntr('00000000 0a'), '000000000B');
+	assert.strictEqual(spNextCntr(''), '0000000001');
+});