Merge upstream/main into feat/webui-compression

Resolve the conflicts against the 41 upstream commits since 52692d0:

- Makefile: keep the upstream parallel-build fixes (grouped html_data
  target with order-only deps, create_build_dir, crtbank, deterministic
  BUILD_DATE, atomic version.h write) and keep the minify + gzip
  pipeline (-z, html_min, .css/.ico in the html file list) on top.
- html: l2.js stays removed; port the upstream L2 fixes into the
  single-page main.js (walkL2() with empty-reply and 4096-entry cap
  handling, 3 retries on error).  The L2 poll now re-schedules itself
  after each walk and stops when the section is hidden.
- httpd/httpd.c merged cleanly (gzip Content-Encoding alongside the
  upstream GET walk bound and counters.json port check).
- doc/webui-compression.md: describe the upstream version.h write.

Verified: KP_9000_6XHML_X2 and PCB_K0402WS_V3 build sequentially and
with make -j8; all 8 embedded files decompress byte-identically;
httpd_sim serves main.js/index.html and the L2 JSON endpoint.

httpd/httpd.c

@@ -640,7 +640,7 @@ void httpd_appcall(void)
 		p += 4;
 		scan_header(p);
 		__xdata uint8_t *q = p;
-		while (!is_separator(*p))
+		while (*p && !is_separator(*p))
 			p++;
 		*p = '\0';
 		dbg_string_x(q);
@@ -664,7 +664,16 @@ void httpd_appcall(void)
 				parse_short(q + 15);
 				send_vlan(short_parsed);
 			} else if (is_word(q, "/counters.json")) {
-				send_counters(q[20]-'0');
+				/* The port is one raw character of the request line and
+				 * indexes a nine entry table, so bound it here instead
+				 * of trusting the client to have sent a digit. Anything
+				 * below '0' wraps well past eight, so the one test
+				 * covers both ends. */
+				uint8_t cport = q[20] - '0';
+				if (cport > 8)
+					send_bad_request();
+				else
+					send_counters(cport);
 			} else if (is_word(q, "/eee.json")) {
 				send_eee();
 			} else if (is_word(q, "/bandwidth.json")) {

httpd/page_impl.c

@@ -356,6 +356,7 @@ void send_l2(uint16_t idx)
 	 */
 	__xdata uint16_t entry = idx & 0xfff;
 	__xdata uint16_t first_entry = 0xffff; // An illegal entry index
+	__bit first = true;
 	char_to_html('[');
 	while (1) {
 		entries_left--;
@@ -369,9 +370,22 @@ void send_l2(uint16_t idx)
 		} while (sfr_data[3] & TBL_EXECUTE);
 
 		reg_read_m(RTL837x_L2_DATA_OUT_B);
-		if ((sfr_data[0] & 0x20)) {	// Check entry is valid
+		__bit valid = (sfr_data[0] & 0x20) != 0;
+		if (valid) {
+			/* separator + 74-byte worst-case entry + closing "]" */
+			if (slen + 76 > TCP_OUTBUF_SIZE)
+				break;
+			if (!first)
+				char_to_html(',');
+			first = false;
+
+			// VLAN, taken from the read above instead of reading the register twice
+			slen += strtox(outbuf + slen, "{\"vlan\":\"");
+			charhex_to_html(sfr_data[0] & 0x0f);
+			byte_to_html(sfr_data[1]);
+
 			// MAC
-			slen += strtox(outbuf + slen, "{\"mac\":\"");
+			slen += strtox(outbuf + slen, "\",\"mac\":\"");
 			byte_to_html(sfr_data[2]); char_to_html(':');
 			byte_to_html(sfr_data[3]); char_to_html(':');
 			port = (sfr_data[0] >> 6) & 0x3;
@@ -381,12 +395,6 @@ void send_l2(uint16_t idx)
 			byte_to_html(sfr_data[2]); char_to_html(':');
 			byte_to_html(sfr_data[3]);
 
-			// VLAN
-			slen += strtox(outbuf + slen, "\",\"vlan\":\"");
-			reg_read_m(RTL837x_L2_DATA_OUT_B);
-			charhex_to_html(sfr_data[0] & 0x0f);
-			byte_to_html(sfr_data[1]);
-
 			// type
 			reg_read_m(RTL837x_L2_DATA_OUT_C);
 			if (sfr_data[2] & 0x1)
@@ -396,32 +404,26 @@ void send_l2(uint16_t idx)
 
 			port |= (sfr_data[3] & 0x3) << 2;
 			itoa_html(port);
+		}
 
-			// Index
-			reg_read_m(RTL837x_TBL_DATA_0);
-			entry = (((uint16_t)sfr_data[2] & 0x0f) << 8) | sfr_data[3];
+		// Index
+		reg_read_m(RTL837x_TBL_DATA_0);
+		entry = (((uint16_t)sfr_data[2] & 0x0f) << 8) | sfr_data[3];
+		if (valid) {
 			slen += strtox(outbuf + slen, ",\"idx\":\"");
 			byte_to_html(entry >> 8);
 			byte_to_html(entry);
 			char_to_html('"');
 			char_to_html('}');
-			entry += 1; // We want the next entry following after the current entry
-		} else {
-			reg_read_m(RTL837x_TBL_DATA_0);
-			entry = (((uint16_t)sfr_data[2] & 0x0f) << 8) | sfr_data[3] + 1;
 		}
-		if (first_entry == 0xffff) {
-			char_to_html(',');
+		entry += 1; // We want the next entry following after the current entry
+
+		if (first_entry == 0xffff)
 			first_entry = entry;
-		} else {
-			if (first_entry == entry || !entries_left) {
-				char_to_html(']');
-				break;
-			} else {
-				char_to_html(',');
-			}
-		}
+		else if (first_entry == entry || !entries_left)
+			break;
 	}
+	char_to_html(']');
 }
 
 
@@ -518,8 +520,7 @@ void send_lag(void)
 		slen += strtox(outbuf + slen, "{\"lagNum\":");
 		itoa_html(l);
 		slen += strtox(outbuf + slen, ",\"members\":\"");
-		reg_read_m(RTL837X_TRK_MBR_CTRL_BASE + (l << 2));
-		uint16_t ports = ((uint16_t)sfr_data[2] << 8) | sfr_data[3];
+		uint16_t ports = port_lag_members_get(l);
 		for (uint8_t i = 0; i < 16; i++) {
 			bool_to_html(!!(ports & 0x8000));
 			ports <<= 1;