backport: T4815: Fix various name server config issues

This is a backport of https://github.com/vyos/vyos-1x/pull/1656.

Note I also changed `ip-down.script.tmpl` to not wait for `systemctl
stop dhcp6c@$iface.service`, because that command is slow and pppd will
kill the ip-down script if it times out.

I didn't see `ip-down.script.tmpl` or its equivalent in the 1.4 branch.
Not sure if there is another mechanism to handle that functionality or
it is missed.

7 files changed, 47 insertions, 10 deletions

diff --git a/data/templates/pppoe/ip-down.script.tmpl b/data/templates/pppoe/ip-down.script.tmpl
index bac4155d6..c1d1132b3 100644
--- a/data/templates/pppoe/ip-down.script.tmpl
+++ b/data/templates/pppoe/ip-down.script.tmpl
@@ -33,6 +33,6 @@ vtysh -c "conf t" ${VRF_NAME} -c "no ipv6 route ::/0 {{ ifname }} ${VRF_NAME}"
 {% endif %}
 
 {% if dhcpv6_options is defined and dhcpv6_options.pd is defined %}
-# Stop wide dhcpv6 client
-systemctl stop dhcp6c@{{ ifname }}.service
+# Stop wide dhcpv6 client without blocking (by default the ip-down script can only run up to 5 seconds)
+systemctl stop --no-block dhcp6c@{{ ifname }}.service
 {% endif %}
diff --git a/debian/vyos-1x.postinst b/debian/vyos-1x.postinst
index d54f6c5af..6ff466c27 100644
--- a/debian/vyos-1x.postinst
+++ b/debian/vyos-1x.postinst
@@ -36,7 +36,7 @@ chsh -s /bin/sh proxy
 
 # Remove unwanted daemon files from /etc
 # conntackd
-DELETE="/etc/logrotate.d/conntrackd.distrib /etc/init.d/conntrackd /etc/default/conntrackd"
+DELETE="/etc/logrotate.d/conntrackd.distrib /etc/init.d/conntrackd /etc/default/conntrackd /etc/ppp/ip-up.d/0000usepeerdns /etc/ppp/ip-down.d/0000usepeerdns"
 for file in $DELETE; do
     if [ -f ${file} ]; then
         rm -f ${file}
diff --git a/src/etc/dhcp/dhclient-enter-hooks.d/04-vyos-resolvconf b/src/etc/dhcp/dhclient-enter-hooks.d/04-vyos-resolvconf
index b1902b585..518abeaec 100644
--- a/src/etc/dhcp/dhclient-enter-hooks.d/04-vyos-resolvconf
+++ b/src/etc/dhcp/dhclient-enter-hooks.d/04-vyos-resolvconf
@@ -33,8 +33,8 @@ if /usr/bin/systemctl -q is-active vyos-hostsd; then
         if [ -n "$new_dhcp6_name_servers" ]; then
             logmsg info "Deleting nameservers with tag \"dhcpv6-$interface\" via vyos-hostsd-client"
             $hostsd_client --delete-name-servers --tag "dhcpv6-$interface"
-            logmsg info "Adding nameservers \"$new_dhcpv6_name_servers\" with tag \"dhcpv6-$interface\" via vyos-hostsd-client"
-            $hostsd_client --add-name-servers $new_dhcpv6_name_servers --tag "dhcpv6-$interface"
+            logmsg info "Adding nameservers \"$new_dhcp6_name_servers\" with tag \"dhcpv6-$interface\" via vyos-hostsd-client"
+            $hostsd_client --add-name-servers $new_dhcp6_name_servers --tag "dhcpv6-$interface"
             hostsd_changes=y
         fi
 
diff --git a/src/etc/dhcp/dhclient-exit-hooks.d/01-vyos-cleanup b/src/etc/dhcp/dhclient-exit-hooks.d/01-vyos-cleanup
index eac860cd8..378f74741 100644
--- a/src/etc/dhcp/dhclient-exit-hooks.d/01-vyos-cleanup
+++ b/src/etc/dhcp/dhclient-exit-hooks.d/01-vyos-cleanup
@@ -8,7 +8,7 @@ hostsd_changes=
 /usr/bin/systemctl -q is-active vyos-hostsd
 hostsd_status=$?
 
-if [[ $reason =~ (EXPIRE|FAIL|RELEASE|STOP) ]]; then
+if [[ $reason =~ ^(EXPIRE|FAIL|RELEASE|STOP)$ ]]; then
     if [[ $hostsd_status -eq 0 ]]; then
         # delete search domains and nameservers via vyos-hostsd
         logmsg info "Deleting search domains with tag \"dhcp-$interface\" via vyos-hostsd-client"
@@ -96,7 +96,7 @@ if [[ $reason =~ (EXPIRE|FAIL|RELEASE|STOP) ]]; then
     fi
 fi
 
-if [[ $reason =~ (EXPIRE6|RELEASE6|STOP6) ]]; then
+if [[ $reason =~ ^(EXPIRE6|RELEASE6|STOP6)$ ]]; then
     if [[ $hostsd_status -eq 0 ]]; then
         # delete search domains and nameservers via vyos-hostsd
         logmsg info "Deleting search domains with tag \"dhcpv6-$interface\" via vyos-hostsd-client"
diff --git a/src/etc/dhcp/dhclient-exit-hooks.d/vyatta-dhclient-hook b/src/etc/dhcp/dhclient-exit-hooks.d/vyatta-dhclient-hook
index eeb8b0782..49bb18372 100644
--- a/src/etc/dhcp/dhclient-exit-hooks.d/vyatta-dhclient-hook
+++ b/src/etc/dhcp/dhclient-exit-hooks.d/vyatta-dhclient-hook
@@ -8,12 +8,12 @@
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
-# 
+#
 # This program is distributed in the hope that it will be useful, but
 # WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 # General Public License for more details.
-# 
+#
 # This code was originally developed by Vyatta, Inc.
 # Portions created by Vyatta are Copyright (C) 2006, 2007, 2008 Vyatta, Inc.
 # All Rights Reserved.
@@ -23,7 +23,7 @@
 RUN="yes"
 
 proto=""
-if [[ $reason =~ (REBOOT6|INIT6|EXPIRE6|RELEASE6|STOP6|INFORM6|BOUND6|REBIND6|DELEGATED6) ]]; then
+if [[ $reason =~ ^(REBOOT6|INIT6|EXPIRE6|RELEASE6|STOP6|INFORM6|BOUND6|REBIND6|DELEGATED6)$ ]]; then
         proto="v6"
 fi
 
diff --git a/src/etc/ppp/ip-down.d/98-vyos-pppoe-cleanup-nameservers b/src/etc/ppp/ip-down.d/98-vyos-pppoe-cleanup-nameservers
new file mode 100755
index 000000000..5157469f4
--- /dev/null
+++ b/src/etc/ppp/ip-down.d/98-vyos-pppoe-cleanup-nameservers
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+interface=$6
+if [ -z "$interface" ]; then
+    exit
+fi
+
+if ! /usr/bin/systemctl -q is-active vyos-hostsd; then
+    exit  # vyos-hostsd is not running
+fi
+
+hostsd_client="/usr/bin/vyos-hostsd-client"
+$hostsd_client --delete-name-servers --tag "dhcp-$interface"
+$hostsd_client --apply
diff --git a/src/etc/ppp/ip-up.d/98-vyos-pppoe-setup-nameservers b/src/etc/ppp/ip-up.d/98-vyos-pppoe-setup-nameservers
new file mode 100755
index 000000000..4affaeb5c
--- /dev/null
+++ b/src/etc/ppp/ip-up.d/98-vyos-pppoe-setup-nameservers
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+interface=$6
+if [ -z "$interface" ]; then
+    exit
+fi
+
+if ! /usr/bin/systemctl -q is-active vyos-hostsd; then
+    exit  # vyos-hostsd is not running
+fi
+
+hostsd_client="/usr/bin/vyos-hostsd-client"
+
+$hostsd_client --delete-name-servers --tag "dhcp-$interface"
+
+if [ "$USEPEERDNS" ] && [ -n "$DNS1" ]; then
+$hostsd_client --add-name-servers "$DNS1" --tag "dhcp-$interface"
+fi
+if [ "$USEPEERDNS" ] && [ -n "$DNS2" ]; then
+$hostsd_client --add-name-servers "$DNS2" --tag "dhcp-$interface"
+fi
+
+$hostsd_client --apply