[init/kexec/] More advanced network setup via KCL, could skip DHCP

If enough information if provided via KCL, we can skip the initial DHCP
request in stage 3.1. Currently we require IP address, subnet mask and
DNS server to skip DHCP. If we extend the boot server to supply a
fallback/default DNS server, we could even do without DNS which would
work in almost all cases.

kexec-reboot has been extended to make use of this feature, but can be
extended even more to provide up to date values from the current system
configuration. Currently, some of the values it provides to the new
kernel will be cached values from stage 3.1.
kexec-reboot also honors the ipxe menu id from the KCL if given, to
properly download the matching menu entry, which will take updates to
the entry into account (e.g. changed URLs to kernel/init).

6 files changed, 80 insertions, 46 deletions

diff --git a/core/rootfs/rootfs-stage31/data/inc/activate_sysconfig b/core/rootfs/rootfs-stage31/data/inc/activate_sysconfig
index 45f3832e..2d6015e1 100644
--- a/core/rootfs/rootfs-stage31/data/inc/activate_sysconfig
+++ b/core/rootfs/rootfs-stage31/data/inc/activate_sysconfig
@@ -42,11 +42,11 @@ merge_text_config() {
 	# write IP and SLX_SERVER configuration to $CONFIG
 cat >> "$CONFIG" <<HEREEND
 # IP Config written in stage31
-SLX_PXE_CLIENT_IP='$CLIENTIP'
+SLX_PXE_CLIENT_IP='$ip'
 SLX_PXE_SERVER_IP='$SERVERIP'
-SLX_PXE_GATEWAY='$GATEWAY'
-SLX_PXE_DNS='$DNS_SERVER'
-SLX_PXE_MAC='$BRIDGEMAC'
+SLX_PXE_GATEWAY='$router'
+SLX_PXE_DNS='$dns'
+SLX_PXE_MAC='$MAC'
 HEREEND
 	return 0
 }
diff --git a/core/rootfs/rootfs-stage31/data/inc/parse_kcl b/core/rootfs/rootfs-stage31/data/inc/parse_kcl
index 95f7daf5..ba2fea8f 100644
--- a/core/rootfs/rootfs-stage31/data/inc/parse_kcl
+++ b/core/rootfs/rootfs-stage31/data/inc/parse_kcl
@@ -5,26 +5,38 @@ getip () {
 }
 parse_ip () {
 	local IPINFO=$1
-	CLIENTIP="$(getip 1)"
+	export ip="$(getip 1)"
 	SERVERIP="$(getip 2)"
-	GATEWAY="$(getip 3)"
-	SUBNET_MASK="$(getip 4)"
-	BROADCAST_ADDRESS="$(ipcalc -s -b "$CLIENTIP" "$SUBNET_MASK" | sed s/.*=//)"
-	[ -z "$BROADCAST_ADDRESS" ] && BROADCAST_ADDRESS="255.255.255.255"
+	export router="$(getip 3)"
+	export subnet="$(getip 4)"
 	# we might have an idea of the dns server via preboot
-	DNS_SERVER="$(getip 5)"
+	export dns="$(getip 5)"
+}
+
+parse_ipv4 () {
+	local var arg
+	var="${1%%=*}"
+	case "$var" in
+		ip|router|dns|hostname|domain|search|if|ntpsrv|subnet) ;;
+		*) return ;;
+	esac
+	arg="$( printf "%s" "${1#*=}" | tr -d "\`'\n\r" )"
+	export "$var=${arg}"
 }
 
 # read kernel command line
 DEBUG=0
 SPLASH=0
-read KCL < "/proc/cmdline"
+read -r KCL < "/proc/cmdline"
 for opts in ${KCL}; do
 	case "${opts}" in
 		debug=*)
 			DEBUG=${opts#debug=}
 			DEBUG_SHELL=set
 			;;
+		ipv4.*)
+			parse_ipv4 "${opts#ipv4.}"
+			;;
 		ip=*)
 			# process IP info
 			parse_ip ${opts#ip=} ;;
@@ -36,9 +48,9 @@ for opts in ${KCL}; do
 		BOOTIF=*)
 			MAC="$( echo "$opts" | cut -b 11- | tr '-' ':' | tr '[A-Z]' '[a-z]' )" ;; # make mac lowercase for udev (see setup_network)
 		slxsrv=*)
-			SLX_KCL_SERVERS=$( echo "${opts#slxsrv=}" | tr ',' " " ) ;;
+			SLX_KCL_SERVERS="$( echo "${opts#slxsrv=}" | tr ',' " " )" ;;
 		slxbase=*)
-			SLX_BASE_PATH=${opts#slxbase=} ;;
+			SLX_BASE_PATH="${opts#slxbase=}" ;;
 		splash)
 			SPLASH=1 ;;
 		nvidia)
@@ -54,8 +66,15 @@ for opts in ${KCL}; do
 	esac
 done
 
+dns="${dns//,/ }"
+search="${search//,/ }"
+ntpsrv="${ntpsrv//,/ }"
+[ -z "$MAC" ] && MAC="${if//-/:}"
+
 # If slxsrv was not given on command line, just use the PXE server's address
 [ -z "$SLX_KCL_SERVERS" ] && [ -n "$SERVERIP" ] && SLX_KCL_SERVERS="$SERVERIP"
+# Reverse case
+[ -z "$SERVERIP" ] && SERVERIP="${SLX_KCL_SERVERS%% *}"
 # Now save to config file
 echo "SLX_KCL_SERVERS='$SLX_KCL_SERVERS'" >> "${FUTURE_ROOT}/opt/openslx/config"
 echo "SLX_BASE_PATH='$SLX_BASE_PATH'" >> "${FUTURE_ROOT}/opt/openslx/config"
diff --git a/core/rootfs/rootfs-stage31/data/inc/setup_network b/core/rootfs/rootfs-stage31/data/inc/setup_network
index 6b97fb18..e407d173 100644
--- a/core/rootfs/rootfs-stage31/data/inc/setup_network
+++ b/core/rootfs/rootfs-stage31/data/inc/setup_network
@@ -47,28 +47,24 @@ for LINE in $IP_OUT; do
 	IFMAC="$( echo "${LINE#*==}" | tr 'A-Z' 'a-z' )" # udev requires mac addesses to be lowercase (a-f), see http://www.debianhelp.co.uk/udev.htm
 	echo "${IFACE} = ${IFMAC}"
 
+	if [ -z "$MAC" ]; then
+		echo "No main MAC address given, trying first interface found..."
+		MAC="$IFMAC"
+	fi
+
 	if [ "x$IFMAC" == "x$MAC" ]; then
+		ip link set dev "$IFACE" up
 		brctl addbr "$BRIDGE" || drop_shell "Could not create bridge $BRIDGE"
 		brctl stp "$BRIDGE" 0
 		brctl setfd "$BRIDGE" 0.000000000001
 		ip link set addr "$IFMAC" "$BRIDGE" || drop_shell "Could not set mac of $BRIDGE"
-		ip link set dev "$IFACE" up
 		wait_for_iface "$IFACE" 8
 		brctl addif "$BRIDGE" "$IFACE" || drop_shell "Could not add $IFACE to $BRIDGE"
 
 		# save our variables for retry on fail
 		echo "IFACE=$IFACE" > /run/network.conf
 
-		# analyze ip information from the kernel command line and put parts
-		# of it into several variables
-		if [ -n "$CLIENTIP" ] ; then
-			# set static ip address
-			ip link set dev "$BRIDGE" up
-			ip addr add "$CLIENTIP/$(ipcalc -s -p "$CLIENTIP" "$SUBNET_MASK" | sed "s/.*=//")" broadcast "$BROADCAST_ADDRESS" dev "$BRIDGE"
-			[ -n "$GATEWAY" ] && ip route add default via "$GATEWAY" dev "$BRIDGE"
-		else
-			ip link set dev "$BRIDGE" up
-		fi
+		ip link set dev "$BRIDGE" up
 		# Ignore this device later on when systemd handles network interfaces (see hacked 99-systemd.rules in systemd data dir)
 		echo "SUBSYSTEM==\"net\", ACTION==\"add\", KERNEL==\"eth*\", ATTR{address}==\"$IFMAC\", TAG+=\"openslxignore\"" >> "${FUTURE_ROOT}/etc/udev/rules.d/01-ignore-boot-interface.rules"
 	else
@@ -90,14 +86,17 @@ done
 
 wait_for_iface "$BRIDGE" 5
 
+# See if we got all required attributes via KCL, in that case skip DHCP
+# TODO: Supply DNS servers in config from boot server, so we can even work witout it
+if [ -n "$ip" ] && [ -n "$router" ] && [ -n "$dns" ]; then
+	echo "Skipping DHCP since we have new style KCL"
+	interface="${BRIDGE}" /inc/udhcpc-trigger bound && return 0
+fi
+
 # udhcpc
 PARAM=
-if [ -n "$CLIENTIP" ]; then
-	PARAM="-r $CLIENTIP"
-	echo -n "$CLIENTIP" > "/run/firstip"
-fi
-if [ -n "$GATEWAY" ]; then
-	echo -n "$GATEWAY" > "/run/firstgw"
+if [ -n "$ip" ]; then
+	PARAM="-r ${ip%/*}"
 fi
 
 if [ "$USE_DHCP_UUID" = "yes" ]; then
@@ -109,15 +108,15 @@ if [ "$USE_DHCP_UUID" = "yes" ]; then
 fi
 
 # save our variables for retry on fail ff.
-echo "CLIENTIP=$CLIENTIP" >> /run/network.conf
-echo "GATEWAY=$GATEWAY" >> /run/network.conf
+echo "ip=$ip" >> /run/network.conf
+echo "router=$router" >> /run/network.conf
 echo "BRIDGE=$BRIDGE" >> /run/network.conf
 echo "UID=$UID" >> /run/network.conf
 
-udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -t 5 -T 3 -A 4 -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE"
+udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -O dns -t 5 -T 3 -A 4 -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE"
 URET=$?
 # if these were empty before, udhcpc might have filled them in
-[ -z "$CLIENTIP" ] && CLIENTIP=$(cat /run/firstip)
-[ -z "$GATEWAY" ] && GATEWAY=$(cat /run/firstgw)
+[ -z "$ip" ] && ip=$(cat /run/firstip)
+[ -z "$router" ] && router=$(cat /run/firstgw)
 # udhcpc return value will be return value of this script
 return $URET
diff --git a/core/rootfs/rootfs-stage31/data/inc/setup_network_retry b/core/rootfs/rootfs-stage31/data/inc/setup_network_retry
index c1fff39d..449c0d8f 100644
--- a/core/rootfs/rootfs-stage31/data/inc/setup_network_retry
+++ b/core/rootfs/rootfs-stage31/data/inc/setup_network_retry
@@ -17,11 +17,11 @@ for i in 1 2 3 4 5 6 7 8; do
 	wait_for_iface "$IFACE" "$(( 15 + i * 2 ))"
 	retval=$?
 	ip link set dev "$BRIDGE" up
-	if [ "$retval" -eq 0 ] && [ "$i" -ge 4 ] && [ -n "$CLIENTIP" ] && [ -n "$GATEWAY" ]; then
+	if [ "$retval" -eq 0 ] && [ "$i" -ge 4 ] && [ -n "$ip" ] && [ -n "$router" ]; then
 		echo "....."
 		usleep 100000
 		echo "Checking if static IP config works...."
-		if ping -c1 -w2 "$GATEWAY" &> /dev/null || ping -c1 -w2 "$SERVERIP" &> /dev/null; then
+		if ping -c1 -w2 "$router" &> /dev/null || ping -c1 -w2 "${SLX_KCL_SERVERS%% *}" &> /dev/null; then
 			echo "apparently so."
 			echo "Trying to boot without DHCP config (DNS, Hostname, ...), YMMV!"
 			sleep 3
@@ -33,8 +33,8 @@ for i in 1 2 3 4 5 6 7 8; do
 	wait_for_iface "$BRIDGE" 10
 	usleep 100000
 
-	udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -t "$(( 2 + i / 2 ))" -T "$(( 4 + i ))" -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE" \
-		|| udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -t "$(( 2 + i / 2 ))" -T "$(( 4 + i ))" -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE"
+	udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -O dns -t "$(( 2 + i / 2 ))" -T "$(( 4 + i ))" -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE" \
+		|| udhcpc $PARAM -O hostname -O ntpsrv -O domain -O search -O dns -t "$(( 2 + i / 2 ))" -T "$(( 4 + i ))" -s "/inc/udhcpc-trigger" -f -n -q -i "$BRIDGE"
 	RET="$?"
 
 	if [ "$RET" -eq 0 ]; then
diff --git a/core/rootfs/rootfs-stage31/data/inc/udhcpc-trigger b/core/rootfs/rootfs-stage31/data/inc/udhcpc-trigger
index 795dd8a0..cc7454e7 100755
--- a/core/rootfs/rootfs-stage31/data/inc/udhcpc-trigger
+++ b/core/rootfs/rootfs-stage31/data/inc/udhcpc-trigger
@@ -1,13 +1,27 @@
 #!/bin/ash
 
-exec >> /run/stdout
 exec 2>> /run/stderr
 set -x
 
 if [ "x$1" != "xbound" -a "x$1" != "xrenew" ] || [ "x$interface" != "xbr0" ] || [ -z "$ip" ]; then
+	echo "Ignoring DHCP hook '$1' for interface '$interface' -> '$ip'"
 	exit 0
 fi
 
+if [ "$ip" != "${ip#*/}" ]; then # CIDR
+	cidr="$ip"
+	ip="${ip%/*}"
+elif [ -n "$mask" ]; then
+	cidr="$ip/$mask"
+else
+	if [ -z "$subnet" ]; then
+		echo "$1 event with missing subnet mask"
+		exit 1
+	fi
+	# Non-CIDR + mask
+	cidr="$ip/$( ipcalc -s -p "$ip" "$subnet" | sed 's/.*=//' )"
+fi
+
 # If we already got an IP from KCL, see if it differs, and remove first if so
 # We just try to prevent everything from breaking if the DHCP server doesn't
 # objey the renew request by the client and hands out a new address
@@ -21,14 +35,14 @@ if [ -s "/run/firstip" ]; then
 		ip route del default 2>/dev/null
 		rm -f -- "/run/firstgw"
 		ip addr del "${OLD}" dev "${interface}" 2>/dev/null
-		ip addr add "${ip}/$(ipcalc -s -p "${ip}" "${subnet}" | sed s/.*=//)" dev "${interface}"
+		ip addr add "${cidr}" dev "${interface}"
 	fi
 else
 	#...no address configured yet, just add...
 	echo "..adding ${ip}.."
-	ip addr add "${ip}/$(ipcalc -s -p "${ip}" "${subnet}" | sed s/.*=//)" dev "${interface}"
+	ip addr add "${cidr}" dev "${interface}"
 fi
-echo -n "$ip" > "/run/firstip"
+printf "%s" "$ip" > "/run/firstip"
 
 # Same procedure for default gateway
 if [ -n "${router}" ]; then
@@ -42,7 +56,7 @@ if [ -n "${router}" ]; then
 	else
 		ip route add default via "$router"
 	fi
-	echo -n "$router" > "/run/firstgw"
+	printf "%s" "$router" > "/run/firstgw"
 fi
 
 rm -f -- "/etc/resolv.conf"
@@ -56,7 +70,7 @@ fi
 for serv in $dns; do
 	echo "nameserver $serv" >> "/etc/resolv.conf"
 done
-if [ -z "$domain" ]; then
+if [ -z "$domain" ] && [ -n "$dns" ]; then
 	# try to get domain via reverse lookup if empty
 	echo "..trying to get domain via DNS, as DHCP didn't supply one.."
 	fqdn=$(timeout -t 3 nslookup "$ip" | grep -E "^Address +[0-9]+: +$ip " | head -n 1 | awk '{print $4}')
@@ -92,7 +106,7 @@ done
 if [ -z "$hostname" ]; then
 	# as with domain, if there's no hostname, try to get via DNS
 	echo "..trying to get hostname via DNS, as DHCP didn't supply one.."
-	[ -z "$fqdn" ] && fqdn=$(timeout -t 3 nslookup "$ip" | grep -E "^Address +[0-9]+: +$ip " | head -n 1 | awk '{print $4}')
+	[ -z "$fqdn" ] && [ -n "$dns" ] && fqdn=$(timeout -t 3 nslookup "$ip" | grep -E "^Address +[0-9]+: +$ip " | head -n 1 | awk '{print $4}')
 	hostname="${fqdn%%.*}"
 elif [ -n "$domain" ]; then
 	fqdn="${hostname}.${domain}"
@@ -111,3 +125,4 @@ if [ -n "$hostname" ]; then
 	echo "SLX_HOSTNAME='$hostname'" >> "/run/config"
 fi
 
+exit 0
diff --git a/core/rootfs/rootfs-stage31/data/init b/core/rootfs/rootfs-stage31/data/init
index c848493a..54102c8c 100755
--- a/core/rootfs/rootfs-stage31/data/init
+++ b/core/rootfs/rootfs-stage31/data/init
@@ -208,6 +208,7 @@ echo "Switching root...."
 echo "$bench_result" > "${FUTURE_ROOT}/opt/openslx/.benchmark"
 # Prepare environment (HOME is needed as a hack for nss_ldap with ssl and no caching)
 unset BOOT_IMAGE initrd KCL ip slxbase slxsrv IPINFO vga ip MAC BOOTIF DEBUG OLDPWD MUTED_OUTPUT GFX
+unset ip router dns hostname domain search if ntpsrv
 export HOME=/
 export init="/usr/lib/systemd/systemd"
 export recovery=