gateway-dk-ask: use explicit xtables module list in build and packaging

Replace the libxt_*.c glob in the build step and libxt_qos*/libxt_QOS*
glob in the packaging step with a single explicit list of module names.
Both steps now reference the same ask_xtables_modules array, so adding
or removing a module requires updating only one place per function.

The packaging step now errors out if any expected .so is missing instead
of silently skipping it.

Also document why we don't use pkg-config for libxtables: these are
dlopen()-loaded extensions that don't link against libxtables.so and
use our local UAPI headers (xt_QOSMARK.h etc.) which aren't in
libxtables-dev.

Author: Tomaz Zaman

extensions/gateway-dk-ask.sh

@@ -272,18 +272,25 @@ function pre_customize_image__001_build_ask_userspace() {
 	cp "${ASK_CACHE_DIR}/${ASK_DPA_APP_DIR}/files/etc/cdx_sp.xml" "${SDCARD}/etc/"
 
 	# --- xtables extensions (standalone .so files, not patching iptables) ---
+	# Note: we don't use pkg-config for libxtables here. These are dlopen()-loaded
+	# extensions — they don't link against libxtables.so, they use symbols resolved
+	# from the iptables process that loads them. The -I./include picks up our local
+	# xt_QOSMARK.h etc. UAPI headers which aren't in libxtables-dev (they're our
+	# additions). Adding -lxtables would cause duplicate symbol issues at load time.
+	local ask_xtables_modules=(libxt_qosmark libxt_QOSMARK libxt_qosconnmark libxt_QOSCONNMARK)
 	display_alert "ASK extension" "building xtables extensions" "info"
 	cp -a "${ASK_CACHE_DIR}/iptables-extensions" "${SDCARD}/tmp/ask-userspace/iptables-extensions"
 	chroot_sdcard "cd /tmp/ask-userspace/iptables-extensions && \
-		for src in libxt_*.c; do \
-			name=\"\${src%.c}\"; \
+		for name in ${ask_xtables_modules[*]}; do \
 			gcc -shared -fPIC -O2 \
 				-D_init=\${name}_init \
 				-I./include \
-				-o \"\${name}.so\" \"\${src}\" || exit 1; \
+				-o \"\${name}.so\" \"\${name}.c\" || exit 1; \
 		done && \
 		install -d /usr/lib/${ASK_HOST_TRIPLET}/xtables && \
-		install -m 644 libxt_*.so /usr/lib/${ASK_HOST_TRIPLET}/xtables/" \
+		for name in ${ask_xtables_modules[*]}; do \
+			install -m 644 \"\${name}.so\" /usr/lib/${ASK_HOST_TRIPLET}/xtables/ || exit 1; \
+		done" \
 		|| exit_with_error "xtables extensions build failed"
 
 	# --- Patched system libraries (must be before CMM which depends on patched libnetfilter-conntrack) ---
@@ -376,11 +383,13 @@ function pre_customize_image__001_build_ask_userspace() {
 		done
 	done
 
-	# xtables extensions (QOSMARK/QOSCONNMARK)
+	# xtables extensions — use the same explicit list as the build step
+	local ask_xtables_modules=(libxt_qosmark libxt_QOSMARK libxt_qosconnmark libxt_QOSCONNMARK)
 	mkdir -p "${pkgdir}/usr/lib/${ASK_HOST_TRIPLET}/xtables"
-	for f in "${SDCARD}/usr/lib/${ASK_HOST_TRIPLET}/xtables/"libxt_qos*.so \
-	         "${SDCARD}/usr/lib/${ASK_HOST_TRIPLET}/xtables/"libxt_QOS*.so; do
-		[[ -f "$f" ]] && cp -a "$f" "${pkgdir}/usr/lib/${ASK_HOST_TRIPLET}/xtables/"
+	for name in "${ask_xtables_modules[@]}"; do
+		local src="${SDCARD}/usr/lib/${ASK_HOST_TRIPLET}/xtables/${name}.so"
+		[[ -f "${src}" ]] || exit_with_error "xtables extension missing" "${name}.so"
+		cp -a "${src}" "${pkgdir}/usr/lib/${ASK_HOST_TRIPLET}/xtables/"
 	done
 
 	# Version: kernel version + build date — allows bugfix rebuilds without kernel change