From 6995afb6f1b01938e4a3ca0daf375dfe276181d5 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Wed, 11 Aug 2021 15:58:09 +0200
Subject: Implement blocking network.target and network-online.target

Add two services that will delay reaching the according targets, until
conditions we consider reasonable are reached.
For network.target that is finishing DHCP for the primary interface, for
network-online.target we want to see a default gateway or a proxy server
configured.
Both have a timeout of about 10 seconds for now; this might be increased
later on, if necessary.
---
 .../data/opt/openslx/scripts/udhcpc-openslx        | 37 ++++++----------------
 .../data/etc/systemd/system/network-dns.target     |  2 --
 .../data/etc/systemd/system/network-gateway.target |  2 --
 .../network-online.target.d/00-slx-targets.conf    |  4 ---
 .../network-online-slx-targets/module.build        | 12 -------
 .../modules/network-online-slx-targets/module.conf |  1 -
 .../data/etc/sysctl.d/90-openslx.conf              |  3 ++
 .../slx-wait-online.service                        |  1 +
 .../slx-wait-primary-dhcp.service                  |  1 +
 .../etc/systemd/system/slx-wait-online.service     |  7 ++++
 .../systemd/system/slx-wait-primary-dhcp.service   |  7 ++++
 .../data/opt/openslx/scripts/systemd-wait_online   | 21 ++++++++++++
 .../opt/openslx/scripts/systemd-wait_primary_dhcp  | 18 +++++++++++
 .../slx-network-configs-targets/module.build       | 12 +++++++
 .../slx-network-configs-targets/module.conf        |  1 +
 .../systemd/system/early-network-triggers.service  | 13 --------
 .../data/etc/systemd/system/network-dns.target     |  4 ---
 .../data/etc/systemd/system/network-gateway.target |  4 ---
 .../early-network-triggers.service                 |  1 -
 .../openslx/scripts/systemd-early_network_triggers | 33 -------------------
 core/targets/bwlp/slx-network-configs-targets      |  1 +
 core/targets/stage4/network-online-slx-targets     |  1 -
 22 files changed, 81 insertions(+), 105 deletions(-)
 delete mode 100644 core/modules/network-online-slx-targets/data/etc/systemd/system/network-dns.target
 delete mode 100644 core/modules/network-online-slx-targets/data/etc/systemd/system/network-gateway.target
 delete mode 100644 core/modules/network-online-slx-targets/data/etc/systemd/system/network-online.target.d/00-slx-targets.conf
 delete mode 100644 core/modules/network-online-slx-targets/module.build
 delete mode 100644 core/modules/network-online-slx-targets/module.conf
 create mode 100644 core/modules/slx-network-configs-targets/data/etc/sysctl.d/90-openslx.conf
 create mode 120000 core/modules/slx-network-configs-targets/data/etc/systemd/system/network-online.target.wants/slx-wait-online.service
 create mode 120000 core/modules/slx-network-configs-targets/data/etc/systemd/system/network.target.wants/slx-wait-primary-dhcp.service
 create mode 100644 core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-online.service
 create mode 100644 core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-primary-dhcp.service
 create mode 100755 core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_online
 create mode 100755 core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_primary_dhcp
 create mode 100644 core/modules/slx-network-configs-targets/module.build
 create mode 100644 core/modules/slx-network-configs-targets/module.conf
 delete mode 100644 core/rootfs/rootfs-stage32/data/etc/systemd/system/early-network-triggers.service
 delete mode 100644 core/rootfs/rootfs-stage32/data/etc/systemd/system/network-dns.target
 delete mode 100644 core/rootfs/rootfs-stage32/data/etc/systemd/system/network-gateway.target
 delete mode 120000 core/rootfs/rootfs-stage32/data/etc/systemd/system/sysinit.target.wants/early-network-triggers.service
 delete mode 100755 core/rootfs/rootfs-stage32/data/opt/openslx/scripts/systemd-early_network_triggers
 create mode 120000 core/targets/bwlp/slx-network-configs-targets
 delete mode 120000 core/targets/stage4/network-online-slx-targets

diff --git a/core/modules/dhcpc-busybox/data/opt/openslx/scripts/udhcpc-openslx b/core/modules/dhcpc-busybox/data/opt/openslx/scripts/udhcpc-openslx
index 05cded10..3e30da55 100755
--- a/core/modules/dhcpc-busybox/data/opt/openslx/scripts/udhcpc-openslx
+++ b/core/modules/dhcpc-busybox/data/opt/openslx/scripts/udhcpc-openslx
@@ -24,6 +24,7 @@ declare -rg primary="${SLX_BRIDGE:-br0}"
 
 declare -rg RESOLV_CONF="/opt/openslx/resolv.conf"
 declare -rg THIS_RESOLV="/run/network/${interface}.resolv"
+declare -rg flag="/run/network/primary-dhcp.flag"
 
 shopt -s extglob
 
@@ -94,15 +95,6 @@ check_env() {
 	fi
 }
 
-if [ ! -d /run ]; then
-	echo -n "Waiting for /run." >&2
-	while [ ! -d /run ]; do
-		echo -n "." >&2
-		usleep 500000
-	done
-	echo "" >&2
-fi
-
 mkdir -p "/run/network"
 
 case "$1" in
@@ -190,34 +182,31 @@ case "$1" in
 			fi
 			
 			# Only if network is not ready yet
-			if ! [ -e "/run/network/network-ready" ] || ! [ -e "/etc/hostname" ] || grep -q '^noname-' "/etc/hostname"; then
+			if ! [ -e "$flag" ]; then
 				# Update hostname
 				if [ -z "$dns_fqdn" ] && [ -n "$domain" ] && [ -n "$hostname" ]; then
 					# fallback to what the dhcp told us
 					dns_fqdn="${hostname}.${domain}"
 				fi
-				if [ -z "$dns_fqdn" ]; then
-					# only if there is no /etc/hostname, we fall back (far back, that is)
-					[ ! -s "/etc/hostname" ] && dns_fqdn="slx-client"
+				if [ -z "$dns_fqdn" ] && ! [ -s "/etc/hostname" ]; then
+					dns_fqdn="noname-${ip//./-}"
 				fi
 				# finally, if dns_fqdn was set to anything, apply it
 				if [ -n "$dns_fqdn" ]; then
 					dns_short="${dns_fqdn%%.*}"
 					echo "$dns_short" > "/proc/sys/kernel/hostname"
 					echo "$dns_short" > "/etc/hostname"
-					if grep '^SLX_HOSTNAME=' /opt/openslx/config 2>/dev/null; then
-						sed -i "s/^\(SLX_HOSTNAME=\).*$/\1'$dns_short'/" /opt/openslx/config
-					else
+					if [ -z "$SLX_HOSTNAME" ]; then
 						echo "# Config written by openslx-dhcp-script (1)" >> /opt/openslx/config
 						echo "SLX_HOSTNAME='$dns_short'" >> /opt/openslx/config
+					elif [ "$SLX_HOSTNAME" != "$dns_short" ]; then
+						sed -i "s/^\(SLX_HOSTNAME=\).*$/\1'$dns_short'/" /opt/openslx/config
 					fi
 				fi
 
 				# Update /etc/issue for proper spacing
 				/opt/openslx/scripts/openslx-create_issue
-				touch "/run/network/network-ready"
-				# Mark network target as reached
-				systemctl start network.target &
+				touch "$flag"
 			fi # end "network not ready yet"
 			# Remove any stray addresses; we expect the primary interface to only have one
 			# address supplied via DHCP. We do this after adding the new one, obviously.
@@ -253,18 +242,10 @@ case "$1" in
 		# Get rid of orphaned lines in /etc/hosts
 		sed -i -r '/^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+\s*$/d' /etc/hosts
 		
-		# "dns ready" target
-		if [ -n "$dns" ] && [ ! -e "/run/network/dns-ready" ]; then
-			touch "/run/network/dns-ready"
+		if [ -n "$dns" ] && [ -z "$SLX_DNS" ]; then
 			# Write to openslx-config
 			echo "# Config written by openslx-dhcp-script (2)" >> /opt/openslx/config
 			echo "SLX_DNS='$dns'" >> /opt/openslx/config
-			systemctl start network-dns.target &
-		fi
-		# "default route exists" target
-		if [ -n "$router" ] && [ ! -e "/run/network/gateway-ready" ]; then
-			touch "/run/network/gateway-ready"
-			systemctl start network-gateway.target &
 		fi
 	;;
 	
diff --git a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-dns.target b/core/modules/network-online-slx-targets/data/etc/systemd/system/network-dns.target
deleted file mode 100644
index 8bc541ab..00000000
--- a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-dns.target
+++ /dev/null
@@ -1,2 +0,0 @@
-[Unit]
-Description=DNS Server available
diff --git a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-gateway.target b/core/modules/network-online-slx-targets/data/etc/systemd/system/network-gateway.target
deleted file mode 100644
index 11139162..00000000
--- a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-gateway.target
+++ /dev/null
@@ -1,2 +0,0 @@
-[Unit]
-Description=Default route configured
diff --git a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-online.target.d/00-slx-targets.conf b/core/modules/network-online-slx-targets/data/etc/systemd/system/network-online.target.d/00-slx-targets.conf
deleted file mode 100644
index 81208043..00000000
--- a/core/modules/network-online-slx-targets/data/etc/systemd/system/network-online.target.d/00-slx-targets.conf
+++ /dev/null
@@ -1,4 +0,0 @@
-[Unit]
-Wants=network-gateway.target network-dns.target network.target
-Before=network-gateway.target network-dns.target
-After=network.target
diff --git a/core/modules/network-online-slx-targets/module.build b/core/modules/network-online-slx-targets/module.build
deleted file mode 100644
index 241bcd5e..00000000
--- a/core/modules/network-online-slx-targets/module.build
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/bin/bash
-fetch_source() {
-	:
-}
-
-build() {
-	pinfo "Static module, nothing to build."
-}
-
-post_copy() {
-	:
-}
diff --git a/core/modules/network-online-slx-targets/module.conf b/core/modules/network-online-slx-targets/module.conf
deleted file mode 100644
index c01ade29..00000000
--- a/core/modules/network-online-slx-targets/module.conf
+++ /dev/null
@@ -1 +0,0 @@
-# Nothing
diff --git a/core/modules/slx-network-configs-targets/data/etc/sysctl.d/90-openslx.conf b/core/modules/slx-network-configs-targets/data/etc/sysctl.d/90-openslx.conf
new file mode 100644
index 00000000..04f988df
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/etc/sysctl.d/90-openslx.conf
@@ -0,0 +1,3 @@
+# Make sure ARP replies only go out on the matching interface
+net.ipv4.conf.all.arp_filter=1
+net.ipv4.conf.default.arp_filter=1
diff --git a/core/modules/slx-network-configs-targets/data/etc/systemd/system/network-online.target.wants/slx-wait-online.service b/core/modules/slx-network-configs-targets/data/etc/systemd/system/network-online.target.wants/slx-wait-online.service
new file mode 120000
index 00000000..8e346eac
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/etc/systemd/system/network-online.target.wants/slx-wait-online.service
@@ -0,0 +1 @@
+../slx-wait-online.service
\ No newline at end of file
diff --git a/core/modules/slx-network-configs-targets/data/etc/systemd/system/network.target.wants/slx-wait-primary-dhcp.service b/core/modules/slx-network-configs-targets/data/etc/systemd/system/network.target.wants/slx-wait-primary-dhcp.service
new file mode 120000
index 00000000..e7f32c14
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/etc/systemd/system/network.target.wants/slx-wait-primary-dhcp.service
@@ -0,0 +1 @@
+../slx-wait-primary-dhcp.service
\ No newline at end of file
diff --git a/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-online.service b/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-online.service
new file mode 100644
index 00000000..7765ebdd
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-online.service
@@ -0,0 +1,7 @@
+[Unit]
+Description=Wait until we are online, ie. a gateway or proxy is configured
+Before=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart=/opt/openslx/scripts/systemd-wait_online
diff --git a/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-primary-dhcp.service b/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-primary-dhcp.service
new file mode 100644
index 00000000..68dc13f7
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/etc/systemd/system/slx-wait-primary-dhcp.service
@@ -0,0 +1,7 @@
+[Unit]
+Description=Wait until DHCP for the primary NIC has finished
+Before=network.target
+
+[Service]
+Type=oneshot
+ExecStart=/opt/openslx/scripts/systemd-wait_primary_dhcp
diff --git a/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_online b/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_online
new file mode 100755
index 00000000..aaee9c32
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_online
@@ -0,0 +1,21 @@
+#!/bin/ash
+
+# Wait until we have a nameserver in resolv.conf
+# and we have a gateway configured
+
+w=0
+while ! grep -q ^nameserver /etc/resolv.conf && [ "$w" -lt 10 ]; do
+	let w++
+	sleep 1
+done
+
+# We don't consider a missing nameserver fatal, but a missing gateway, if no proxy is set
+. /etc/profile
+while [ -z "$http_proxy" ] && [ -z "$ALL_PROXY" ] && ! ip route show | grep -q ^default; do
+	[ "$w" -gt 12 ] && exit 1 # Give up - not online
+	let w++
+	sleep 1
+	. /etc/profile
+done
+
+exit 0
diff --git a/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_primary_dhcp b/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_primary_dhcp
new file mode 100755
index 00000000..3e452549
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/data/opt/openslx/scripts/systemd-wait_primary_dhcp
@@ -0,0 +1,18 @@
+#!/bin/ash
+
+flag="/run/network/primary-dhcp.flag"
+readonly flag
+w=0
+
+# Wait a maximum of 10 seconds for the flag file
+while ! [ -e "$flag" ] && [ "$w" -lt 10 ]; do
+	let w++
+	sleep 1
+done
+
+# Then touch it anyways, this will prevent the DHCP
+# trigger script from changing the hostname later on
+mkdir -p /run/network
+touch "$flag"
+
+exit 0
diff --git a/core/modules/slx-network-configs-targets/module.build b/core/modules/slx-network-configs-targets/module.build
new file mode 100644
index 00000000..241bcd5e
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/module.build
@@ -0,0 +1,12 @@
+#!/bin/bash
+fetch_source() {
+	:
+}
+
+build() {
+	pinfo "Static module, nothing to build."
+}
+
+post_copy() {
+	:
+}
diff --git a/core/modules/slx-network-configs-targets/module.conf b/core/modules/slx-network-configs-targets/module.conf
new file mode 100644
index 00000000..c01ade29
--- /dev/null
+++ b/core/modules/slx-network-configs-targets/module.conf
@@ -0,0 +1 @@
+# Nothing
diff --git a/core/rootfs/rootfs-stage32/data/etc/systemd/system/early-network-triggers.service b/core/rootfs/rootfs-stage32/data/etc/systemd/system/early-network-triggers.service
deleted file mode 100644
index 2c5d7769..00000000
--- a/core/rootfs/rootfs-stage32/data/etc/systemd/system/early-network-triggers.service
+++ /dev/null
@@ -1,13 +0,0 @@
-# This will trigger network.target etc. at an early point,
-# if network setup happened in stage31 (dhcp...)
-[Unit]
-Description=Trigger network targets early
-DefaultDependencies=no
-Wants=systemd-tmpfiles-setup.service
-Before=sysinit.target
-After=systemd-tmpfiles-setup.service
-
-[Service]
-Type=oneshot
-ExecStart=/opt/openslx/scripts/systemd-early_network_triggers
-RemainAfterExit=yes
diff --git a/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-dns.target b/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-dns.target
deleted file mode 100644
index bc12cd1b..00000000
--- a/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-dns.target
+++ /dev/null
@@ -1,4 +0,0 @@
-[Unit]
-Description=DNS Server available
-ConditionPathExists=/run/network/dns-ready
-
diff --git a/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-gateway.target b/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-gateway.target
deleted file mode 100644
index 770eb697..00000000
--- a/core/rootfs/rootfs-stage32/data/etc/systemd/system/network-gateway.target
+++ /dev/null
@@ -1,4 +0,0 @@
-[Unit]
-Description=Default route configured
-ConditionPathExists=/run/network/gateway-ready
-
diff --git a/core/rootfs/rootfs-stage32/data/etc/systemd/system/sysinit.target.wants/early-network-triggers.service b/core/rootfs/rootfs-stage32/data/etc/systemd/system/sysinit.target.wants/early-network-triggers.service
deleted file mode 120000
index 8aec0a6d..00000000
--- a/core/rootfs/rootfs-stage32/data/etc/systemd/system/sysinit.target.wants/early-network-triggers.service
+++ /dev/null
@@ -1 +0,0 @@
-../early-network-triggers.service
\ No newline at end of file
diff --git a/core/rootfs/rootfs-stage32/data/opt/openslx/scripts/systemd-early_network_triggers b/core/rootfs/rootfs-stage32/data/opt/openslx/scripts/systemd-early_network_triggers
deleted file mode 100755
index 64ea853e..00000000
--- a/core/rootfs/rootfs-stage32/data/opt/openslx/scripts/systemd-early_network_triggers
+++ /dev/null
@@ -1,33 +0,0 @@
-#!/bin/ash
-
-# This script will trigger several network targets if
-# applicable at an early point.
-# This happens if dhcp/network setup was successful in stage31
-
-# Main interface
-BRIDGE="br0"
-
-if [ ! -e "/sys/class/net/${BRIDGE}/operstate" -o "x$(cat "/sys/class/net/${BRIDGE}/operstate")" == "xup" ] && [ -e "/opt/openslx/uniontmp/etc/hostname" -o -e "/etc/resolv.conf" ]; then
-	echo "Triggering network.target"
-	touch "/run/network/network-ready"
-	systemctl start network.target &
-fi
-
-if [ -s "/etc/resolv.conf" ] && grep -q "^nameserver" "/etc/resolv.conf"; then
-	echo "Triggering network-dns.target"
-	touch "/run/network/dns-ready"
-	systemctl start network-dns.target &
-fi
-
-if route -n | grep -q -E '^0\.0\.0\.0.*U.*G'; then
-	echo "Triggering network-gateway.target"
-	touch "/run/network/gateway-ready"
-	systemctl start network-gateway.target &
-fi
-
-# In case we have multiple NICs per subnet, don't send arp
-# replies on all NICs
-echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
-
-exit 0
-
diff --git a/core/targets/bwlp/slx-network-configs-targets b/core/targets/bwlp/slx-network-configs-targets
new file mode 120000
index 00000000..9aa45e71
--- /dev/null
+++ b/core/targets/bwlp/slx-network-configs-targets
@@ -0,0 +1 @@
+../../modules/slx-network-configs-targets
\ No newline at end of file
diff --git a/core/targets/stage4/network-online-slx-targets b/core/targets/stage4/network-online-slx-targets
deleted file mode 120000
index b022ecc2..00000000
--- a/core/targets/stage4/network-online-slx-targets
+++ /dev/null
@@ -1 +0,0 @@
-../../modules/network-online-slx-targets
\ No newline at end of file
-- 
cgit v1.2.3-55-g7522