Merge ~smoser/ubuntu/+source/resolvconf:bug/1675571-add-rc-prog into ~usd-import-team/ubuntu/+source/resolvconf:ubuntu/devel

[Scott Moser]

allow setting of program name via dns-iface-name option in interfaces(5).

When ifupdown has multiple addresses for a given interface, integration
with resolvconf is broken. This is because resolvconf is called for each
stanza, but the scripts in /etc/network/if-*.d/ invoke
  resolvconf -a IFACE.PROG
or
  resolvconf -d IFACE.PROG
with IFACE being the interface name, and PROG set to ADDRFAM, where
ADDRFAM is only 'inet' or 'inet6'.

The solution here is to allow the author of interfaces(5) to provide
the program name via option 'dns-iface-name'.

As an example:
 auto eth0
 iface eth0 inet static
    address 138.197.98.102/20
    gateway 138.197.96.1
    dns-nameservers 8.8.8.8
    dns-iface-name public0

 iface eth0 inet static
    address 10.17.0.11/16
    dns-iface-name local

LP: #1675571

[Scott Moser (smoser)]

Since it is resolvconf that adds the dns-* entries to interfaces,
a.) this should be adjusted to just use that namespace (change resolvconf-prog to dns-program-name)
b.) need to document this in man/resolvconf.8

[Scott Moser (smoser)]

review: Needs Fixing

[Scott Moser (smoser)]

I addressed 'a' and 'b' above, but then realized that the dhclient script does not have access to the IF_* variables. so this does not work if any dhcp are used.

[Scott Moser (smoser)]

> I addressed 'a' and 'b' above, but then realized that the dhclient script does
> not have access to the IF_* variables. so this does not work if any dhcp are
> used.

Well, i was sort of right.
dhclient ends up using a resolvconf like the following
  ipv4: /sbin/resolvconf -a "${interface}.dhclient"
  ipv6: /sbin/resolvconf -a "${interface}.ip6.dhclient"

So it turns out that this will work. 'dhcp' or dhcpv6' stanzas will not overwrite any *non* dhcp stanzas, but you can't have 2 ipv4 or 2 ipv6 dhcp stanzas or *they* would fight.

[Scott Moser (smoser)]

review: Approve

[Scott Moser (smoser)]

The other option for this is to not require the ENI author to put these variables in, but instead have ifupdown provide a consistent value that resolvconf could use. But that would have to be made consistent across changes to the file, deletes of interfaces or adds of interfaces in any order.

Ie, this has to work for any ordering of eth1 and eth0 or their multiple stanzas inside an ENI.

ifup eth1
ifup eth0
ifdown eth0
# edit ENI, remove eth1
ifup down eth0

Unmerged commits

257b73e... by Scott Moser on 2017-03-28

update changelog

5a54f58... by Scott Moser on 2017-03-28

allow setting of program name via dns-iface-name option in interfaces(5).

When ifupdown has multiple addresses for a given interface, integration
with resolvconf is broken. This is because resolvconf is called for each
stanza, but the scripts in /etc/network/if-*.d/ invoke
  resolvconf -a IFACE.PROG
or
  resolvconf -d IFACE.PROG
with IFACE being the interface name, and PROG set to ADDRFAM, where
ADDRFAM is only 'inet' or 'inet6'.

The solution here is to allow the author of interfaces(5) to provide
the program name via option 'dns-iface-name'.

As an example:
 auto eth0
 iface eth0 inet static
    address 138.197.98.102/20
    gateway 138.197.96.1
    dns-nameservers 8.8.8.8
    dns-iface-name public0

 iface eth0 inet static
    address 10.17.0.11/16
    dns-iface-name local

LP: #1675571

diff --git a/debian/changelog b/debian/changelog
index c02f413..92e04ae 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,13 @@
+resolvconf (1.79ubuntu5) UNRELEASED; urgency=medium
+
+  * debian/resolvconf.*.if-{up,down}:
+    allow setting of program name through the dns-iface-name option in
+    interfaces(5).  This allows users or tools to author interfaces
+    so that multiple stanzas do not collide in their dns settings.
+    (LP: #1675571)
+
+ -- Scott Moser <[e-mail]>  Tue, 28 Mar 2017 12:26:54 -0400
+
 resolvconf (1.79ubuntu4) zesty; urgency=medium
 
   * debian/resolvconf.service: Add missing Wants=network-pre.target.
diff --git a/debian/resolvconf.000resolvconf.if-up b/debian/resolvconf.000resolvconf.if-up
index f799371..498c97e 100755
--- a/debian/resolvconf.000resolvconf.if-up
+++ b/debian/resolvconf.000resolvconf.if-up
@@ -7,10 +7,15 @@
 
 [ -x /sbin/resolvconf ] || exit 0
 
-case "$ADDRFAM" in
-  inet|inet6) : ;;
-  *) exit 0 ;;
-esac
+if [ -n "${IF_DNS_IFACE_NAME}" ]; then
+  IFACE_NAME="${IF_DNS_IFACE_NAME}"
+else
+  case "$ADDRFAM" in
+    inet|inet6) : ;;
+    *) exit 0 ;;
+  esac
+  IFACE_NAME="${IFACE}.${ADDRFAM}"
+fi
 
 R=""
 if [ "$IF_DNS_DOMAIN" ] ; then
@@ -43,5 +48,5 @@ for OPT in $IF_DNS_NAMESERVER ; do
 done
 IFS="$STANDARD_IFS"
 
-echo -n "$R" | /sbin/resolvconf -a "${IFACE}.${ADDRFAM}" || :
+echo -n "$R" | /sbin/resolvconf -a "${IFACE_NAME}" || :
 
diff --git a/debian/resolvconf.000resolvconf.ppp.ip-down b/debian/resolvconf.000resolvconf.ppp.ip-down
index 561ef41..a0458fd 100755
--- a/debian/resolvconf.000resolvconf.ppp.ip-down
+++ b/debian/resolvconf.000resolvconf.ppp.ip-down
@@ -17,5 +17,5 @@ case "$6" in
     ;;
 esac
 
-/sbin/resolvconf -d "${PPP_IFACE}.pppd"
+/sbin/resolvconf -d "${IF_DNS_IFACE_NAME:-${PPP_IFACE}.pppd}"
 
diff --git a/debian/resolvconf.000resolvconf.ppp.ip-up b/debian/resolvconf.000resolvconf.ppp.ip-up
index c83ea18..5090123 100755
--- a/debian/resolvconf.000resolvconf.ppp.ip-up
+++ b/debian/resolvconf.000resolvconf.ppp.ip-up
@@ -29,5 +29,5 @@ if [ "$DNS2" ] ; then
 "
 fi
 
-echo -n "$R" | /sbin/resolvconf -a "${PPP_IFACE}.pppd"
+echo -n "$R" | /sbin/resolvconf -a "${IF_DNS_IFACE_NAME:-${PPP_IFACE}.pppd}"
 
diff --git a/debian/resolvconf.resolvconf.if-down b/debian/resolvconf.resolvconf.if-down
index 66e3a9f..1883261 100755
--- a/debian/resolvconf.resolvconf.if-down
+++ b/debian/resolvconf.resolvconf.if-down
@@ -7,10 +7,15 @@
 
 [ -x /sbin/resolvconf ] || exit 0
 
-case "$ADDRFAM" in
-  inet|inet6) :      ;;
-  *)          exit 0 ;;
-esac
+if [ -n "${IF_DNS_IFACE_NAME}" ]; then
+  IFACE_NAME="${IF_DNS_IFACE_NAME}"
+else
+  case "$ADDRFAM" in
+    inet|inet6) :      ;;
+    *)          exit 0 ;;
+  esac
+  IFACE_NAME="${IFACE}.${ADDRFAM}"
+fi
 
-/sbin/resolvconf -d "${IFACE}.${ADDRFAM}" || :
+/sbin/resolvconf -d "${IFACE_NAME}" || :
 
diff --git a/man/resolvconf.8 b/man/resolvconf.8
index fd4b417..f29e7ce 100644
--- a/man/resolvconf.8
+++ b/man/resolvconf.8
@@ -114,6 +114,17 @@ option is also accepted and, unlike
 can be given multiple arguments,
 separated by spaces.
 .PP
+The
+.B dns-iface-name
+option controls what interface name will be given to resolvconf
+when it is invoked by the
+.IR ifup.d
+or
+.IR ifdown.d
+scripts.  No value is required.  The default depends
+on how the device is configured.  This is useful if you have multiple
+addresses configured for a single device with separate stanzas.
+.PP
 The 
 .B dns\-domain
 option is deprecated in favor of
@@ -130,6 +141,7 @@ The resulting stanza might look like the following example.
         dns\-nameserver 192.168.1.254
         dns\-nameserver 8.8.8.8
         dns\-search foo.org bar.com
+        dns\-iface\-name eth0.foobar
 .EE
 .PP
 N.B.: On a machine where resolvconf