From c533543d40247ce6ab6d34bcf94aa8ab174bfc7e Mon Sep 17 00:00:00 2001
From: Robby Workman <rworkman@slackware.com>
Date: Thu, 13 Jul 2017 14:24:05 -0500
Subject: rc.inet1.*: Added support for IP address aliases

This is accomplished with a new parameter in rc.inet1.conf:
  IPALIASES[$index]="space separated list of addresses"

The aliases are added with a /32 mask and a label of
${interface}:{$number} to remain compatible with net-tools.

IP address aliases are supported for both statically configured
interfaces and dhcp-configured interfaces, although they'll only
be configured for dhcp if the dhcpcd call succeeds.
  * note: I don't what happens if dhcpcd gets IPv4LL address
---
 rc.inet1      | 18 ++++++++++++++++++
 rc.inet1.conf |  5 +++++
 2 files changed, 23 insertions(+)

diff --git a/rc.inet1 b/rc.inet1
index 871b38d..091dcfe 100644
--- a/rc.inet1
+++ b/rc.inet1
@@ -200,6 +200,15 @@ if_up() {
         # 10 seconds should be a reasonable default DHCP timeout.  30 was too much.
         echo "/etc/rc.d/rc.inet1:  /sbin/dhcpcd -L -t ${DHCP_TIMEOUT[$i]:-10} ${DHCP_OPTIONS} ${1}" | $LOGGER
         /sbin/dhcpcd -L -t ${DHCP_TIMEOUT[$i]:-10} ${DHCP_OPTIONS} ${1}
+        # If the dhcpcd call succeeds, add extra IP addresses, if defined, to interface
+        if [ "$?" == "0" -a ! -z "${IPALIASES[$1]}" ]; then
+          num=0
+          for ipalias in $(echo ${IPALIASES[$i]}); do
+            /sbin/ip address add ${ipalias}/32 dev ${1} label ${1}:${num} ;
+            num=$(($num + 1))
+          done
+          unset num
+        fi
       else # bring up interface using a static IP address
         if [ ! "${IPADDR[$i]}" = "" ]; then # skip unconfigured interfaces
           # Determine broadcast address from the IP address and netmask:
@@ -211,6 +220,15 @@ if_up() {
           if /sbin/ip link show dev ${1} | grep -wq "state DOWN" ; then
             /sbin/ip link set dev ${1} up  # Bring up interface
           fi
+          # Add extra IP addresses, if defined, to interface
+          if [ ! -z "${IPALIASES[$i]}" ]; then
+            num=0
+            for ipalias in $(echo ${IPALIASES[$i]}); do
+              /sbin/ip address add ${ipalias}/32 dev ${1} label ${1}:${num} ;
+              num=$(($num + 1))
+            done
+            unset num
+          fi
         else
           if [ "$DEBUG_ETH_UP" = "yes" ]; then
             echo "/etc/rc.d/rc.inet1:  ${1} interface is not configured in /etc/rc.d/rc.inet1.conf" | $LOGGER
diff --git a/rc.inet1.conf b/rc.inet1.conf
index 93b3e6c..7fcc9bb 100644
--- a/rc.inet1.conf
+++ b/rc.inet1.conf
@@ -16,24 +16,28 @@
 # Config information for eth0:
 IPADDR[0]=""
 NETMASK[0]=""
+IPALIASES[0]=""
 USE_DHCP[0]=""
 DHCP_HOSTNAME[0]=""
 
 # Config information for eth1:
 IPADDR[1]=""
 NETMASK[1]=""
+IPALIASES[1]=""
 USE_DHCP[1]=""
 DHCP_HOSTNAME[1]=""
 
 # Config information for eth2:
 IPADDR[2]=""
 NETMASK[2]=""
+IPALIASES[2]=""
 USE_DHCP[2]=""
 DHCP_HOSTNAME[2]=""
 
 # Config information for eth3:
 IPADDR[3]=""
 NETMASK[3]=""
+IPALIASES[3]=""
 USE_DHCP[3]=""
 DHCP_HOSTNAME[3]=""
 
@@ -52,6 +56,7 @@ DEBUG_ETH_UP="no"
 #BRNICS[0]="eth0"
 #IPADDR[0]="192.168.0.1"
 #NETMASK[0]="255.255.255.0"
+#IPALIASES[0]=""
 #USE_DHCP[0]=""
 #DHCP_HOSTNAME[0]=""
 
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