From 52086c9f22d2e95a96e2a27c96fa4f184dca986e Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 1 Mar 2024 15:01:56 +0100
Subject: [slx-network] Get rid of rdns

---
 modules.d/slx-network/hooks/s3-copy-network-files.sh |  8 --------
 modules.d/slx-network/module-setup.sh                |  1 -
 modules.d/slx-network/scripts/udhcpc-trigger.stage4  | 11 ++++++++++-
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/modules.d/slx-network/hooks/s3-copy-network-files.sh b/modules.d/slx-network/hooks/s3-copy-network-files.sh
index 46f4ab38..0b8577c0 100755
--- a/modules.d/slx-network/hooks/s3-copy-network-files.sh
+++ b/modules.d/slx-network/hooks/s3-copy-network-files.sh
@@ -19,12 +19,4 @@ mkdir -p "${NEWROOT}/opt/openslx"
 mv "${NEWROOT}/etc/resolv.conf" "${NEWROOT}/opt/openslx/resolv.conf"
 ln -nfs "/opt/openslx/resolv.conf" "${NEWROOT}/etc/resolv.conf"
 
-# HACK: finally make sure we have rdns helper
-# This should be done more elegantly one day...
-rdns="$( command -p rdns )"
-if [ -n "$rdns" ]; then
-	mkdir -p "${NEWROOT}/opt/openslx/bin"
-	cp -f "$rdns" "${NEWROOT}/opt/openslx/bin"
-fi
-
 exit 0
diff --git a/modules.d/slx-network/module-setup.sh b/modules.d/slx-network/module-setup.sh
index d907da51..3684d161 100755
--- a/modules.d/slx-network/module-setup.sh
+++ b/modules.d/slx-network/module-setup.sh
@@ -27,7 +27,6 @@ install() {
 	inst "${moddir}/scripts/udhcpc-trigger.stage3" "/usr/local/bin/udhcpc-trigger"
 
 	# files for stage4, park them in /opt/openslx
-	gcc -o "${initdir}/usr/local/bin/rdns" "${moddir}/rdns.c"
 	inst "${moddir}/scripts/s3-setup-bootif-network.stage4" "/opt/openslx/scripts/s3-setup-bootif-network.stage4"
 	inst "${moddir}/scripts/udhcpc-trigger.stage4" "/opt/openslx/scripts/udhcpc-trigger.stage4"
 	inst "${moddir}/services/udhcpc-bootif-stage4.service" "/opt/openslx/services/udhcpc-bootif.service"
diff --git a/modules.d/slx-network/scripts/udhcpc-trigger.stage4 b/modules.d/slx-network/scripts/udhcpc-trigger.stage4
index c2ea566a..5c02190b 100755
--- a/modules.d/slx-network/scripts/udhcpc-trigger.stage4
+++ b/modules.d/slx-network/scripts/udhcpc-trigger.stage4
@@ -59,6 +59,15 @@ check_env() {
 	fi
 }
 
+reverse_lookup() {
+	[ -z "$1" ] && return
+	timeout 3 nslookup "$1" | awk '{
+		if ($2 == "name") { print gensub("\\.$", "", 1, $4); exit; }
+		if ($1 == "Name:") { ok = 1 }
+		if (ok && $1 == "Address") { print gensub("\\.$", "", 1, $4); exit; }
+	}'
+}
+
 case "$1" in
 	bound|renew)
 		check_env "$1"
@@ -74,7 +83,7 @@ case "$1" in
 		fi
 		
 		# get domain, hostname and thus fqdn from DNS
-		dns_fqdn=$(busybox timeout 3 rdns "$ip")
+		dns_fqdn=$( reverse_lookup "$ip" )
 		dns_short="${dns_fqdn%%.*}"
 		# check if it is fqdn
 		if [ "$dns_fqdn" == "$dns_short" ]; then
-- 
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