Andrej’s notes

A new version of ifupdown has been uploaded to experimental yesterday, which brings some important changes.

First of all, now it's possible to specify default values for various interface configuration options. This eliminates the need of hard coding of them in C source, as Ubuntu has been doing for some time. End users are not affected by this change at all, of course.

Second, now ifup behaves differently when it's called with --all option. Previously, that was causing all interfaces marked as 'auto' to be brought up. Now, it does exactly the same if --allow option isn't used. Otherwise, it brings up the interfaces which are declared to belong to a specified class using allow-* directive. In other words, 'auto' directive indeed declares interface as belonging to a class 'auto', and the default class for ifupdown is also 'auto', so when user runs ifup -a only those interfaces are brought up.

Also, when called with --all, both ifup and ifdown now also call hook scripts before doing anything and just after that. Specifically, before bringing interfaces up, it calls pre-up scripts with a special interface name and a special address family (which can't happen otherwise), and calls post-up scripts after doing everything it needs. Same happens with ifdown, but it calls different scripts, of course. This feature helps to avoid manual parsing of /etc/network/interfaces and /run/network/ifstate as mountnfs script did (and still does), for example. In theory, exactly none of the existing scripts should be broken by this change. At least, I couldn't find any of distribution-supplied scripts which could break. Also, Network Manager already uses similar approach, so if anything can break, it's been broken for a long time already.

One more change is related to the initscript. /etc/init.d/ifupdown is no more. However, ifupdown now provides /etc/init.d/networking instead of netbase. This means, the next version of netbase needs to drop it, and also setting up Breaks relationship would be cool. The script itself has been changed a bit. Apart from other things, now it supports reload command properly, grabbing the current interfaces state and bringing those interfaces back up. Also, start command now tries to bring up interfaces which are specified with 'allow-hotplug' if they can be brought up.

Cool news for Ubuntu maintainers and everyone else interested: now ifupdown supports ifquery interface previously available in Ubuntu only. It has some bugs fixed, and now seems to work properly with mappings and already-up interfaces.

Finally, /run transition has almost finished, so please if you opened any related bugs, please test and report if they still need fixing.

Also, this version (with one more bug discovered while preparing this post fixed) is going to be upload to unstable as soon as enough people test it to be sure it's not going to Break Everything At All. In that upload, I plan to temporarily unapply a controversial patch already discussed on debian-devel@ which changed the processing of hook scripts' return values.

Please do test and report any bugs you find.

And, of course, a short summary of the changes:

• Prefer isc-dhcp-client to dhcp3-client (also closes: #422885).
• Let dhclient fail when no lease can be acquired (Closes: #420784).
• Raise command-line options priority over /etc/network/interfaces (Closes: #657743).
• Prevent aliases and VLANs from putting the main interface down (Closes: #656270).
• Make iproute2 calculate the broadcast address (LP: #924880).
• Shut udhcpc down correctly (Closes: #338348).
• Update the rules according to /run migration.
• Pass hardening flags from dpkg-buildflags (Closes: #661243).
• Implement ifquery interface (Closes: #568479).
  • Make ifquery process mappings (LP: #850166).
  • Ensure ifquery always has no_act turned on.
• Change --all behaviour:
  • If ifup or ifquery is called with the --all option, if doesn't just bring up all interfaces marked as "auto", but all interfaces of a specified class, "auto" by default. For the most uses, this doesn't change anything, but lets all the interfaces of a specific class to be brought up or queried.
• Support cross-compilation, move Debian-specific things out of the Makefile (Closes: #666084).
• Take networking init script over from netbase package.
  • Add reload action which reconfigures all interfaces currently configured.
  • Add LSB Description field.
  • Remove /usr from PATH.
  • Merge ifupdown initscript in.
  • Improve warning messages.
  • Don't use redirection hacks when parsing /proc/mounts and /proc/swap.
  • Document all supported subcommands.
  • On start, try to configure hotplug interfaces if they seem to be ready. Ignore errors if they fail to configure for some reason (for example, if the interface happens to be renamed by udev before it's fully configured).
  • Override Lintian's false positives.
• Remove /etc/default/ifupdown.
• Call hook scripts when processing all interfaces:
  • If ifupdown is called with the --all option, before or after doing anything to the interfaces, it calls all the hook scripts (pre-up or down) with IFACE set to "--all", LOGICAL set to the current class specified by the --allow option (or "auto" if it's not set), ADDRFAM="meta" and METHOD="none".
• Fix IPv6 issue on kFreeBSD.
• Update test suite.
• Improve manual pages.
• Bump Standards-Version to 3.9.3.
• Also closes: #535226:
  • In 0.7~alpha5, "auto" method has been added.

Also posted to debian-devel@ maillist.