alfred: Support interfaces IDs with more than two digits

Occationally /proc/net/if_inet6 contains interface IDs with
three digits. In this case, the regex in wait_for_ll_address()
does not work anymore and alfred is not starting.

This patch changes the evaluation so that fields are used instead
of the mere position by counting characters.

This is a backport from openwrt-routing and can be removed when
updating to OpenWRT 18.06, but not for newer versions of 17.01.

Fixes #98.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Tested-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Robert Langhgammer <rlanghammer@web.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>

build_patches/routing/0001-alfred-Support-interface-IDs-with-more-than-two-digi.patch

@@ -0,0 +1,35 @@
+From 135bc605b4cf91d40ac97f1129a6a5a950f3ff72 Mon Sep 17 00:00:00 2001
+From: Adrian Schmutzler <freifunk@adrianschmutzler.de>
+Date: Mon, 19 Mar 2018 14:16:54 +0100
+Subject: [PATCH] alfred: Support interface IDs with more than two digits
+
+Occationally /proc/net/if_inet6 contains interface IDs with
+three digits. In this case, the regex in wait_for_ll_address()
+does not work anymore and alfred is not starting.
+
+This patch changes the evaluation so that fields are used instead
+of the mere position by counting characters.
+
+Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
+---
+ alfred/files/alfred.init | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/alfred/files/alfred.init b/alfred/files/alfred.init
+index 4c9a9e19..82934368 100755
+--- a/alfred/files/alfred.init
++++ b/alfred/files/alfred.init
+@@ -46,11 +46,11 @@ wait_for_ll_address()
+ 	for i in $(seq $timeout); do
+ 		# We look for
+ 		# - the link-local address (starts with fe80)
+-		# - without tentative flag (bit 0x40 in the flags field; the first char of the flags field begins 38 columns after the fe80 prefix
++		# - without tentative flag (bit 0x40 in the flags field; the first char of the fifth field is evaluated)
+ 		# - on interface $iface
+ 		if awk '
+ 			BEGIN { RET=1 }
+-			/^fe80.{37} [012389ab]/ { if ($6 == "'"$iface"'") RET=0 }
++			$1 ~ /^fe80/ && $5 ~ /^[012389ab]/ && $6 == "'"$iface"'" { RET=0 }
+ 			END { exit RET }
+ 		' /proc/net/if_inet6; then
+ 			return

buildscript

@@ -38,7 +38,8 @@ GLUON_PKGS="kmod-batman-adv-legacy micrond simple-tc uradvd"
 #official openwrt routing packages
 ROUTING=(routing
          https://git.openwrt.org/feed/routing.git
-         d11075cd40a88602bf4ba2b275f72100ddcb4767) # lede-17.01
+         d11075cd40a88602bf4ba2b275f72100ddcb4767
+         "0001-alfred-Support-interface-IDs-with-more-than-two-digi.patch") # lede-17.01
 ROUTING_PKGS="kmod-batman-adv batctl alfred"
 
 FFF=(fff)