tree-wide: remove Emacs lines from all files This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.

Fix IPv6PrivacyExtension (networkd-ndisc.c) This small addition fixes the issues #1982 and #2242. IPv6PrivacyExtension now works as expected even when a RA is received.

Revert "networkd: ndisc - revert to letting the kernel handle NDisc" This reverts commit 23f186494cf041107896fc4bd7fc5b8f921fd79f. The bug has now been fixed, so we can go back to managing this ourselves.

networkd: ndisc - revert to letting the kernel handle NDisc There is still a bug in the userspace version, so temporarily revert this. This is a work-around for issue #1866.

networkd: ndisc - consider configured on timeout Don't block indefinitely, when control has been passed on from NDisc to DHCPv6. In this case there is likely no IPv6 support on the local link, so otherwise this would block indefinitely.

networkd: ndisc - fix token support Fixes CID#1338680. Thanks to Thomas Andersen.

networkd: ndisc/dhcpv6 - handle starting running clients The clients may be triggered to be started repeatedly without being stopped first, simply swallow the error rather than failing the link.

networkd: ndisc - handle router advertisement in userspace Router Discovery is a core part of IPv6, which by default is handled by the kernel. However, the kernel implementation is meant as a fall-back, and to fully support the protocol a userspace implementation is desired. The protocol essentially listens for Router Advertisement packets from routers on the local link and use these to configure the client automatically. The four main pieces of information are: what kind (if any) of DHCPv6 configuration should be performed; a default gateway; the prefixes that should be considered to be on the local link; and the prefixes with which we can preform SLAAC in order to pick a global IPv6 address. A lot of additional information is also available, which we do not yet fully support, but which will eventually allow us to avoid the need for DHCPv6 in the common case. Short-term, the reason for wanting this is in userspace was the desire to fully track all the addresses on links we manage, and that is not possible for addresses managed by the kernel (as the kernel does not expose to us the fact that it manages these addresses). Moreover, we would like to support stable privacy addresses, which will soon be mandated and the legacy MAC-based global addresses deprecated, to do this well we need to handle the generation in userspace. Lastly, more long-term we wish to support more RA options than what the kernel exposes.

networkd: IPv6 router discovery - follow IPv6AcceptRouterAdvertisemnt= The previous behavior: When DHCPv6 was enabled, router discover was performed first, and then DHCPv6 was enabled only if the relevant flags were passed in the Router Advertisement message. Moreover, router discovery was performed even if AcceptRouterAdvertisements=false, moreover, even if router advertisements were accepted (by the kernel) the flags indicating that DHCPv6 should be performed were ignored. New behavior: If RouterAdvertisements are accepted, and either no routers are found, or an advertisement is received indicating DHCPv6 should be performed, the DHCPv6 client is started. Moreover, the DHCP option now truly enables the DHCPv6 client regardless of router discovery (though it will probably not be very useful to get a lease withotu any routes, this seems the more consistent approach). The recommended default setting should be to set DHCP=ipv4 and to leave IPv6AcceptRouterAdvertisements unset.

networkd: dhcp6 - split up configure() method Enabling address acquisition, configuring the client and starting the client are now split out. This to better handle the client being repeatedly enabled due to router advertisements.

sd-ndisc: introduce separate callbacks As the data passed is very different, we introduce four different callbacks: - Generic - router discovery timed out or state machine stopped - Router - router and link configuration received - Prefix onlink - configuration for an onlink prefix received - Prefix autonomous - configuration for to configure a SLAAC address for a prefix received

sd-ndisc: notify user on STOP Also, stop the state machine when we get into a broken state, rather than just notify the user.

util-lib: split our string related calls from util.[ch] into its own file string-util.[ch] There are more than enough calls doing string manipulations to deserve its own files, hence do something about it. This patch also sorts the #include blocks of all files that needed to be updated, according to the sorting suggestions from CODING_STYLE. Since pretty much every file needs our string manipulation functions this effectively means that most files have sorted #include blocks now. Also touches a few unrelated include files.

sd-ndisc: don't inform the caller of expired prefixes The caller should push any lifetime information into the kernel and let the kernel handle prefix expiration.

networkd: dhcp6 - do not handle prefix expiration This ressurects 47d45d3cde45d6545367570264e4e3636bc9e345. We now always use /128 prefixes, so there is no need for the DHCPv6 code to know about prefixes expiring.

networkd: ndisc - split out from dhcp6 code