From 0603354acf21cc77a19b97ae3218ae65cef3d138 Mon Sep 17 00:00:00 2001
From: Marcin Krol <hawk@tld-linux.org>
Date: Tue, 21 May 2024 18:49:48 +0200
Subject: [PATCH] - PLD merge: wait for duplicated IPv6 address detection while
 interface configuration

---
 lib/ifup | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/ifup b/lib/ifup
index b8536af..be231ce 100755
--- a/lib/ifup
+++ b/lib/ifup
@@ -219,6 +219,19 @@ else
 	# IPv6 in use ?
 	if is_yes "$IPV6_NETWORKING" && [ -n "${IP6ADDR}" ]; then
 		ip addr add ${IP6ADDR} dev ${DEVICE} ${IP6ADDROPT}
+		timeout=0
+		while [ $timeout -le 20 ] && \
+		      if_state="`ip -o addr list dev ${DEVICE} to ${IP6ADDR}`" && \
+		      echo "$if_state" | grep -q tentative && \
+		      ! echo "$if_state" | grep -q dadfailed ; do
+			usleep 500000
+			timeout=$((timeout+1))
+		done
+		if ip -o addr list dev ${DEVICE} to ${IP6ADDR} | grep -q dadfailed ; then
+			ip addr del ${IP6ADDR} dev ${DEVICE}
+			nls '%s: Duplicated address detected: %s' "$DEVICE" "$IP6ADDR"
+			exit 1
+		fi
 		if [ -n "${IP6ADDRLABEL}" ]; then
 			ip addrlabel add prefix ${IP6ADDR} dev ${DEVICE} label ${IP6ADDRLABEL}
 		fi
-- 
2.46.0