Change the default value of synchronous_dhclient to NO.

To preserve the existing behavior of etc/rc.d/netif, add code to wait
up to if_up_delay seconds (30 seconds by default) for a default route to
be configured if there are any dhcp interfaces.  This should be extended
to test that the interface is actually up.

X-MFC after:

etc/defaults/rc.conf

@@ -103,7 +103,7 @@ dhclient_flags=""		# Extra flags to pass to dhcp client.
 #dhclient_flags_fxp0=""		# Extra dhclient flags for fxp0 only
 background_dhclient="NO"	# Start dhcp client in the background.
 #background_dhclient_fxp0="YES"	# Start dhcp client on fxp0 in the background.
-synchronous_dhclient="YES"	# Start dhclient directly on configured
+synchronous_dhclient="NO"	# Start dhclient directly on configured
 				# interfaces during startup.
 wpa_supplicant_program="/usr/sbin/wpa_supplicant"
 wpa_supplicant_flags="-s"	# Extra flags to pass to wpa_supplicant
@@ -178,6 +178,7 @@ tcp_drop_synfin="NO"		# Set to YES to drop TCP packets with SYN+FIN
 icmp_drop_redirect="NO" 	# Set to YES to ignore ICMP REDIRECT packets
 icmp_log_redirect="NO"		# Set to YES to log ICMP REDIRECT packets
 network_interfaces="auto"	# List of network interfaces (or "auto").
+if_up_delay="30"		# Time to wait for interfaces to come up.
 cloned_interfaces=""		# List of cloned network interfaces to create.
 #cloned_interfaces="gif0 gif1 gif2 gif3" # Pre-cloning GENERIC config.
 ifconfig_lo0="inet 127.0.0.1"	# default loopback device configuration.

etc/network.subr

@@ -768,6 +768,29 @@ list_net_interfaces()
 	return 0
 }
 
+# get_default_if -address_family
+#	Get the interface of the default route for the given address family.
+#	The -address_family argument must be suitable passing to route(8).
+#
+get_default_if()
+{
+	routeget="`route -n get $1 default 2>/dev/null`"
+	oldifs="$IFS"
+	IFS="
+"
+	defif=
+	for line in $routeget ; do
+		case $line in
+		*interface:*)
+			defif=${line##*: }
+			;;
+		esac
+	done
+	IFS=${oldifs}
+
+	echo $defif
+}
+
 hexdigit()
 {
 	if [ $1 -lt 10 ]; then

etc/rc.d/netif

@@ -70,6 +70,29 @@ network_start()
 	# Configure the interface(s).
 	network_common ifn_start
 
+	if [ -z "$cmdifn" ]; then
+		dhcp_interfaces=`list_net_interfaces dhcp`
+		if [ -n "${dhcp_interfaces}" ]; then
+			delay=${if_up_delay}
+			while [ ${delay} -gt 0 ]; do
+				defif=`get_default_if -inet`
+				if [ -n "${defif}" ]; then
+					if [ ${delay} -ne ${if_up_delay} ]; then
+						echo "($defif)"
+					fi
+					break
+				fi
+				if [ ${delay} -eq ${if_up_delay} ]; then
+					echo -n "Waiting for an interface to come up: "
+				else
+					echo -n .
+				fi
+				sleep 1
+				delay=`expr $delay - 1`
+			done
+		fi
+	fi
+
 	if [ -f /etc/rc.d/ipfilter ] ; then
 		# Resync ipfilter
 		/etc/rc.d/ipfilter quietresync

share/man/man5/rc.conf.5

@@ -393,10 +393,10 @@ only.
 .It Va synchronous_dhclient
 .Pq Bt bool
 Set to
-.Dq Li NO
+.Dq Li YES
 to start
 .Xr dhclient 8
-only in response to interface events and not synchronously at startup.
+synchronously at startup.
 This behavior can be overridden on a per-interface basis by replacing
 the
 .Dq Li DHCP
@@ -406,6 +406,10 @@ variable with
 .Dq Li SYNCDHCP
 or
 .Dq Li NOSYNCDHCP .
+.It Va if_up_delay
+.Pq Vt int
+When set to a positive value, wait up to this long after configuring
+DHCP interfaces at startup to give the interfaces time to receive a lease.
 .It Va firewall_enable
 .Pq Vt bool
 Set to