Add a new configuration variable, ipv4_addrs_<ifn>, which adds one or

more IPv4 address from a ranged list in CIRD notation:

ipv4_addrs_ed0="192.168.0.1/24 192.168.1.1-5/28"

In the process move alias processing into new ipv4_up/down functions to
more toward a less IPv4 centric world.

Submitted by:	Philipp Wuensche <cryx dash freebsd at h3q dot com>

etc/defaults/rc.conf

@@ -154,6 +154,7 @@ ifconfig_lo0="inet 127.0.0.1"	# default loopback device configuration.
 #ifconfig_lo0_alias0="inet 127.0.0.254 netmask 0xffffffff" # Sample alias entry.
 #ifconfig_ed0_ipx="ipx 0x00010010"	# Sample IPX address family entry.
 #ifconfig_fxp0_name="net0"	# Change interface name from fxp0 to net0.
+#ipv4_addrs_fxp0="192.168.0.1/24 192.168.1.1-5/28" # example IPv4 address entry.
 #
 # If you have any sppp(4) interfaces above, you might also want to set
 # the following parameters.  Refer to spppcontrol(8) for their meaning.

etc/network.subr

@@ -198,6 +198,64 @@ wpaif()
 	return 1
 }
 
+# ipv4_up if
+#  add IPv4 addresses to the interface $if 
+ipv4_up()
+{
+	_if=$1
+	ifalias_up ${_if}
+	ipv4_addrs_common ${_if} alias
+}
+
+# ipv4_down if
+#  remove IPv4 addresses from the interface $if
+ipv4_down()
+{
+	_if=$1
+	ifalias_down ${_if}
+	ipv4_addrs_common ${_if} -alias
+}
+
+# ipv4_addrs_common if action
+#   Evaluate the ifconfig_if_ipv4 arguments for interface $if
+#   and use $action to add or remove IPv4 addresses from $if.
+ipv4_addrs_common()
+{  
+	_ret=1
+	_if=$1
+	_action=$2
+    
+	# get ipv4-addresses
+	eval cidr_addr=\${ipv4_addrs_${_if}}
+    
+	for _cidr in ${cidr_addr}; do
+		_ipaddr=${_cidr%%/*}
+		_netmask="/"${_cidr##*/}
+		_range=${_ipaddr##*.}
+		_ipnet=${_ipaddr%.*}
+		_iplow=${_range%-*}
+		_iphigh=${_range#*-}
+
+		# clear netmask when removing aliases
+		if [ "${_action}" = "-alias" ]; then
+			_netmask=""
+		fi
+        
+		_ipcount=${_iplow}
+		while [ "${_ipcount}" -le "${_iphigh}" ]; do
+			eval "ifconfig ${_if} ${_action} ${_ipnet}.${_ipcount}${_netmask}"
+			_ipcount=$((${_ipcount}+1))
+			_ret=0
+
+			# only the first ipaddr in a subnet need the real netmask
+			if [ "${_action}" != "-alias" ]; then
+				_netmask="/32"
+			fi
+		done
+	done
+	return $_ret
+}
+
 # ifalias_up if
 #	Configure aliases for network interface $if.
 #	It returns 0 if at least one alias was configured or

etc/rc.d/netif

@@ -150,7 +150,7 @@ ifn_start()
 
 	ifscript_up ${ifn} && cfg=0
 	ifconfig_up ${ifn} && cfg=0
-	ifalias_up ${ifn} && cfg=0
+	ipv4_up ${ifn} && cfg=0
 	ipx_up ${ifn} && cfg=0
 
 	return $cfg
@@ -165,7 +165,7 @@ ifn_stop()
 	[ -z "$ifn" ] && return 1
 
 	ipx_down ${ifn} && cfg=0
-	ifalias_down ${ifn} && cfg=0
+	ipv4_down ${ifn} && cfg=0
 	ifconfig_down ${ifn} && cfg=0
 	ifscript_down ${ifn} && cfg=0
 

share/man/man5/rc.conf.5

@@ -946,9 +946,26 @@ Such keywords are removed before passing the value to
 .Xr ifconfig 8
 while the order of the other arguments is preserved.
 .Pp
-It is also possible to add IP alias entries here in cases where
-multiple IP addresses registered against a single interface
-are desired.
+One can configure more than one IPv4 address with the
+.Va ipv4_addrs_ Ns Aq Ar interface
+variable.
+One or more IP addresses must be provided in Classless Inter-Domain
+Routing (CIDR) address notation, whose last byte can be a range like
+192.168.0.5-23/24.
+In this case the address 192.168.0.5 will be configured with the
+netmask /24 and the addresses 192.168.0.6 to 192.168.0.23 with
+the non-conflicting netmask /32 as explained in the ifconfig(8)
+alias section.
+With the interface in question being
+.Li ed0,
+an example could look like:
+.Bd -literal
+ipv4_addrs_ed0="192.168.0.1/24 192.168.1.1-5/28"
+.Ed
+.Pp
+It is also possible to add IP alias entries using
+.Xr ifconfig 8
+syntax.
 Assuming that the interface in question was
 .Li ed0 ,
 it might look
@@ -979,6 +996,9 @@ be added since the search would
 stop with the missing
 .Dq Li alias3
 entry.
+Due to this difficult to manage behavior, the
+.Va ifconfig_ Ns Ao Ar interface Ac Ns Va _alias Ns Aq Ar n
+form is deprecated.
 .Pp
 If the
 .Pa /etc/start_if. Ns Aq Ar interface