[slx-network] Overhaul DHCP trigger, generation of resolv.conf, hosts

1 files changed, 70 insertions, 69 deletions

diff --git a/modules.d/slx-network/scripts/udhcpc-trigger.stage3 b/modules.d/slx-network/scripts/udhcpc-trigger.stage3
index 664600a6..fa771868 100755
--- a/modules.d/slx-network/scripts/udhcpc-trigger.stage3
+++ b/modules.d/slx-network/scripts/udhcpc-trigger.stage3
@@ -15,11 +15,15 @@ MAIN_NETIF="$SLX_PXE_NETIF"
 readonly MAIN_NETIF
 
 if [[ "$1" != "bound" && "$1" != "renew" ]] \
-	|| [ "$interface" != "${MAIN_NETIF}" ] \
-	|| [ -z "$ip" ]; then
+		|| [ "$interface" != "${MAIN_NETIF}" ] \
+		|| [ -z "$ip" ]; then
 	exit 0
 fi
 
+log() {
+	echo "${MAIN_NETIF}: $*"
+}
+
 ##
 ## CORE NETWORK CONFIGURATION
 ##
@@ -30,16 +34,16 @@ fi
 # objey the renew request by the client and hands out a new address
 if [ -n "$SLX_PXE_CLIENT_IP" ]; then
 	#...some address is already configured...
-	if [ "x${SLX_PXE_CLIENT_IP}" != "x${ip}" ]; then
+	if [ "${SLX_PXE_CLIENT_IP}" != "${ip}" ]; then
 		#...it's a different one, reconfigure...
-		echo "..reconfiguring '${SLX_PXE_CLIENT_IP}' to '${ip}'."
+		log "reconfiguring from '${SLX_PXE_CLIENT_IP}' to '${ip}'"
 		# remove default route and let it be added again below, as it might get lost when changing the primary address on the interface
-		ip route del default 2>/dev/null
-		ip addr del "$SLX_PXE_CLIENT_IP" dev "${interface}" 2>/dev/null
+		ip route del default
+		ip addr del "$SLX_PXE_CLIENT_IP" dev "${interface}"
 	fi
 else
 	#...no address configured yet, just add...
-	echo "..adding ${ip}.."
+	log "adding ${ip}"
 fi
 if ! ip addr show dev "${interface}" | grep -qF "inet ${ip}/"; then
 	ip addr add "${ip}/$(ipcalc -s -p "${ip}" "${subnet}" | sed s/.*=//)" dev "${interface}"
@@ -49,10 +53,10 @@ fi
 # Same procedure for default gateway
 if [ -n "$router" ]; then
 	if [ -n "$SLX_PXE_GATEWAY" ] && [ "$SLX_PXE_GATEWAY" != "$router" ]; then
-		echo "..reconfiguring default gw from '$SLX_PXE_GATEWAY' to '$router'."
-		ip route del default 2>/dev/null
+		log "reconfiguring default gw from '$SLX_PXE_GATEWAY' to '$router'"
+		ip route del default
 	fi
-	ip route add default via "$router"
+	ip route add default via "$router" dev "${MAIN_NETIF}"
 	echo "SLX_DHCP_GATEWAY='$router'" >> "$NETWORK_CONF"
 fi
 
@@ -67,9 +71,9 @@ reverse_lookup() {
 	[ -z "$dns" ] && return
 	[ -z "$1" ] && return
 	timeout 3 nslookup "$1" | awk '{
-		if ($2 == "name") { print $4; exit; }
+		if ($2 == "name") { print gensub("\.$", "", "", $4); exit; }
 		if ($1 == "Name:") { ok = 1 }
-		if (ok && $1 == "Address") { print $4; exit; }
+		if (ok && $1 == "Address") { print gensub("\.$", "", "", $4); exit; }
 	}'
 }
 
@@ -77,34 +81,61 @@ echo "# From DHCP in stage 3.1" >> "$NETWORK_CONF"
 
 # DNS/domain?
 if [ -n "$dns" ]; then
-	echo "..got DNS.."
+	log "DNS servers: $dns"
 	echo "SLX_DNS='$dns'" >> "$NETWORK_CONF"
+	for srv in $dns; do
+		echo "nameserver $srv" >> "/etc/resolv.conf"
+	done
+else
+	dns="$( < /etc/resolv.conf  awk '$1 == "nameserver" {printf "%s ", $2}' )"
 fi
-for srv in $dns; do
-	echo "nameserver $srv" >> "/etc/resolv.conf"
-done
 
 # always check DNS
-echo "Checking DNS record for this host..."
-[ -z "$fqdn" ] && fqdn="$(reverse_lookup "$ip")"
+log "checking reverse DNS record for this host"
+[ -n "$fqdn" ] && [[ "$fqdn" != *.* ]] && fqdn=
+[ -z "$fqdn" ] && fqdn="$( reverse_lookup "$ip" )"
 [ -z "$fqdn" ] && [ -n "$hostname" ] && [ -n "$domain" ] && fqdn="${hostname}.${domain}"
-# Otherwise, retry DNS one time
+
+# retry DNS one time
 if [ -z "$fqdn" ]; then
+	log "found no way to generate FQDN, trying reverse lookup one more time"
 	sleep 1
-	fqdn="$(reverse_lookup "$ip")"
+	fqdn="$( reverse_lookup "$ip" )"
+fi
+if [ -n "$fqdn" ]; then
+	fqdn_hostname="${fqdn%%.*}"
+	fqdn_domain="${fqdn#*.}"
 fi
-[ -n "$fqdn" ] && fqdn_hostname="${fqdn%%.*}"
 
-if [ -z "$domain" ]; then
-	echo "Getting domain via DNS, as DHCP didn't supply one.."
-	domain="${fqdn#*.}"
+if [ -z "$hostname" ] && [ -n "$fqdn_hostname" ]; then
+	hostname="${fqdn_hostname}"
+	log "using hostname from DNS, as DHCP didn't supply one"
+fi
+if [ -z "$hostname" ] && [ -n "$SLX_PXE_HOSTNAME" ]; then
+	hostname="$SLX_PXE_HOSTNAME"
+	log "using hostname from KCL, as DHCP/DNS didn't supply one"
+fi
+if [ -z "$hostname" ]; then
+	hostname="noname-${ip//./-}"
+	log "got no hostname via DHCP, DNS or KCL, using fallback '$hostname'"
+fi
+if [ -z "$domain" ] && [ -n "$fqdn_domain" ]; then
+	domain="${fqdn_domain}"
+	log "using domain from DNS, as DHCP didn't supply one"
 fi
 
+domain="${domain%% *}" # in case domain is a list, some DHCP servers did that in the past instead of using search
+
+# Normalize to lowercase
+for var in hostname domain fqdn search fqdn_hostname fqdn_domain SLX_PXE_HOSTNAME; do
+	declare "$var"="${!var~~}"
+done
+
 # Add domain to list of search domains if not in there yet
 if [ -n "$domain" ] && [ -n "$search" ]; then
 	FOUND=no
 	for sd in $search; do
-		[ "x$sd" = "x$domain" ] && FOUND=yes
+		[ "$sd" = "$domain" ] && FOUND=yes
 	done
 	[ "$FOUND" = "no" ] && search="$domain $search"
 elif [ -n "$domain" ]; then
@@ -126,51 +157,21 @@ if [ -n "$ntpsrv" ]; then
 	echo "SLX_DHCP_NTP='$ntpsrv'" >> "$NETWORK_CONF"
 fi
 
-# Hostname
-if [ -n "$hostname" ]; then
-	if [ -n "$SLX_PXE_HOSTNAME" ] && [ "$hostname" != "$SLX_PXE_HOSTNAME" ]; then
-		echo "KCL and DHCP hostnames differ... assuming some KCL hack."
-		echo " -> Prefering KCL: '$SLX_PXE_HOSTNAME'."
-		hostname="$SLX_PXE_HOSTNAME"
-	fi
-	if [ -n "$fqdn_hostname" ] && [ "$hostname" != "$fqdn_hostname" ]; then
-		echo "DHCP hostname differs from DNS hostname."
-		echo " -> Prefering DNS: '$fqdn_hostname'."
-		hostname="$fqdn_hostname"
-	fi
-else
-	echo "No hostname specified in DHCP, checking DNS record."
-	# We ignore the corner case where DHCP didn't supply a hostname but
-	# there is a hardcoded one via KCL as it seems unlikely, log it nonetheless
-	if [ -n "$SLX_PXE_HOSTNAME" ]; then
-		echo "DHCP didn't supply a hostname but one was supplied by KCL?" \
-			"This seems strange but using KCL hostname anyways."
-		hostname="$SLX_PXE_HOSTNAME"
-	else
-		# regular fallback to DNS and noname-* if needed
-		if [ -n "$fqdn_hostname" ]; then
-			echo "Using DNS record hostname: '$fqdn_hostname'."
-			hostname="$fqdn_hostname"
-		else
-			# no fallback hostname from DNS, use IP address
-			hostname="noname-${ip//./-}"
-			fqdn="${hostname}.invalid"
-		fi
-		if [ -n "$domain" ]; then
-			fqdn="${hostname}.${domain%% *}" # in case domain is a list
-		fi
-	fi
-fi
+declare -a localnames=()
+[ -n "$fqdn" ] && localnames+=( "$fqdn" )
+[ -n "$hostname" ] && localnames+=( "$hostname" )
+[ -n "$fqdn_hostname" ] && [ "$hostname" != "$fqdn_hostname" ] && localnames+=( "$fqdn_hostname" )
+[ -n "$SLX_PXE_HOSTNAME" ] && [ "$hostname" != "$SLX_PXE_HOSTNAME" ] && localnames+=( "$SLX_PXE_HOSTNAME" )
 
-if [ -n "$hostname" ]; then
-	[ -z "$fqdn" ] && fqdn="$hostname"
-	echo "..setting hostname $hostname (fqdn: $fqdn).."
-	echo "$hostname" > "/proc/sys/kernel/hostname"
-	echo "$hostname" > "/etc/hostname"
-	echo "127.0.0.1 localhost" > "/etc/hosts"
-	echo "$ip $fqdn $hostname" >> "/etc/hosts"
-	echo "SLX_HOSTNAME='$hostname'" >> "$NETWORK_CONF"
-fi
+{
+echo "127.0.0.1 localhost"
+echo "127.0.1.1 ${localnames[*]}"
+} > "/etc/hosts"
+
+log "setting hostname $hostname, FQDN $fqdn"
+echo "$hostname" > "/proc/sys/kernel/hostname"
+echo "$hostname" > "/etc/hostname"
+echo "SLX_HOSTNAME='$hostname'" >> "$NETWORK_CONF"
 
 touch /.network
 set +x