From 1bed8dab31d3b333416c7c7a361318def24f7d35 Mon Sep 17 00:00:00 2001
From: Sean Khan <datapronix@protonmail.com>
Date: Tue, 8 Apr 2025 12:53:42 -0400
Subject: [PATCH] nss-ecm: Improve ECM module configuration handling

This commit fixes two issues with how ECM module options are configured:

1. `/etc/modules.conf` was modified on every ECM start/restart,
   even when no changes were needed.

2. If any other ECM parameters were set in `/etc/modules.conf` it would
   overwrite them as the entire line was replaced.

The solution extracts configuration logic into a dedicated function that
only modifies what's necessary, properly handling all cases (updating existing
parameters, appending to existing options, or creating new options).

Signed-off-by: Sean Khan <datapronix@protonmail.com>
---
 qca-nss-ecm/files/qca-nss-ecm.init | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/qca-nss-ecm/files/qca-nss-ecm.init b/qca-nss-ecm/files/qca-nss-ecm.init
index b27ff2c..8bc7977 100644
--- a/qca-nss-ecm/files/qca-nss-ecm.init
+++ b/qca-nss-ecm/files/qca-nss-ecm.init
@@ -92,13 +92,30 @@ enable_bridge_filtering() {
   fi
 }
 
+set_front_end() {
+  local get_front_end_mode=${1:-0}
+  local module_conf=/etc/modules.conf
+  [ ! -r "$module_conf" ] && touch "$module_conf"
+  # If "options ecm" exists, modify or append front_end_selection
+  if grep -q "^options ecm" "$module_conf"; then
+    if grep -q "front_end_selection=" "$module_conf"; then
+      sed -i -E "s/(options ecm.*)front_end_selection=[0-9]+/\1front_end_selection=$get_front_end_mode/" "$module_conf"
+    else
+      # Append front_end_selection if missing
+      sed -i -E "s/^(options ecm.*)/\1 front_end_selection=$get_front_end_mode/" "$module_conf"
+    fi
+  else
+    # Add new "options ecm" line
+    echo "options ecm front_end_selection=$get_front_end_mode" >> "$module_conf"
+  fi
+}
+
 load_ecm() {
   [ -d /sys/module/ecm ] || {
     local get_front_end_mode
     get_front_end_mode="$(get_front_end_mode)"
     modinfo ecm | awk '/depends/{gsub(",","\n",$NF);print $NF}' | xargs -r -n 1 modprobe
-    touch /etc/modules.conf
-    grep -q "options ecm" /etc/modules.conf || echo "options ecm front_end_selection=$get_front_end_mode" >> /etc/modules.conf
+    set_front_end $get_front_end_mode
     modprobe ecm
     echo 1 > /sys/kernel/debug/ecm/ecm_classifier_default/accel_delay_pkts
   }