[PATCH v2 1/7] lldpd: fixed interface(s) parsing

[Paul Donald]

For interface type parameters, the man page documents patterns:
```
*,!eth*,!!eth1

uses all interfaces, except interfaces starting with "eth",
but including "eth1".
```

While we must check that interfaces exist, first strip any prefixed "!"
then pass the original string (with `!` prefix) again, to command lines.

* Renamed `_ifname` to `_l3dev`.
* Glob pattern `*` is also valid - pass those verbatim.

The net result is that now interface 'names' including globs '*' and '!'
inversions are included in the generated lldpd configs.

We must also `set -o noglob` and `set +o noglob` to disable and enable
globbing respectively, because when we pass `*` as an interface choice
everything goes to hell without them.

Tested extensively on: 22.03.6

Signed-off-by: Paul Donald <newtwen+github at gmail.com>
---
 .../network/services/lldpd/files/lldpd.init   | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/package/network/services/lldpd/files/lldpd.init b/package/network/services/lldpd/files/lldpd.init
index 67ee011ae2..fc53520c5b 100644
--- a/package/network/services/lldpd/files/lldpd.init
+++ b/package/network/services/lldpd/files/lldpd.init
@@ -76,18 +76,32 @@ get_config_restart_hash() {
 }
 
 get_config_cid_ifaces() {
+	set -o noglob
 	local _ifaces
 	config_get _ifaces 'config' "$2"
 
 	local _iface _ifnames=""
 	for _iface in $_ifaces; do
-		local _ifname=""
-		if network_get_device _ifname "$_iface" || [ -e "/sys/class/net/$_iface" ]; then
-			append _ifnames "${_ifname:-$_iface}" ","
+		local _l3dev=""
+		# save any "!" or "!!" prefix from the interface name
+		_suffix=${_iface##*"!"}
+		_prefix=${_iface%%"$_suffix"}
+
+		if network_get_device _l3dev "$_suffix" || [ -e "/sys/class/net/$_suffix" ]; then
+			# prepend the stripped "!" or "!!" prefix here if we had one
+			append _ifnames "$_prefix${_l3dev:-$_suffix}" ","
+		else
+			case $_iface in 
+				*"*"*)
+				# Append any interface names including a glob '*' pattern
+				append _ifnames "$_iface" ","
+				;;
+			esac
 		fi
 	done
 
 	export -n "${1}=$_ifnames"
+	set +o noglob
 }
 
 write_lldpd_conf()
-- 
2.44.0