At least bird's implementation of router advertisement does not
set MTU option by default (instead it supplies an option to the user).
In this case just leave MTU as it is.
When systemd-networkd is run on the same IPv6 enabled interface where
radvd is announcing prefixes, a route is being set up pointing to the
interface address. As this will fail with an invalid argument error,
the link is marked as failed and the following message like the
following will appear in in the logs:
systemd-networkd[21459]: eth1: Could not set NDisc route or address: Invalid argument
systemd-networkd[21459]: eth1: Failed
Should the interface be required by systemd-networkd-wait-online,
network-online.target will wait until its timeout hits thereby
significantly delaying system startup.
The fix is to check whether the gateway address obtained from NDisc
messages is equal to any of the interface addresses on the same link
and not set the NDisc route in that case.
Do not allocate objects of dynamic and potentially large size on the stack
to avoid both clang compilation errors and unpredictable runtime behavior
on exotic platforms. Use the heap for that instead.
While at it, refactor the code a bit. Access 's->domain' via
NDISC_DNSSL_DOMAIN(), and refrain from allocating 'x' independently, but
rather reuse 's' if we're dealing with a new entry to the set.
Fixes#3717
This reworks sd-ndisc and networkd substantially to support IPv6 RA much more
comprehensively. Since the API is extended quite a bit networkd has been ported
over too, and the patch is not as straight-forward as one could wish. The
rework includes:
- Support for DNSSL, RDNSS and RA routing options in sd-ndisc and networkd. Two
new configuration options have been added to networkd to make this
configurable.
- sd-ndisc now exposes an sd_ndisc_router object that encapsulates a full RA
message, and has direct, friendly acessor functions for the singleton RA
properties, as well as an iterative interface to iterate through known and
unsupported options. The router object may either be retrieved from the wire,
or generated from raw data. In many ways the sd-ndisc API now matches the
sd-lldp API, except that no implicit database of seen data is kept. (Note
that sd-ndisc actually had a half-written, but unused implementaiton of such
a store, which is removed now.)
- sd-ndisc will now collect the reception timestamps of RA, which is useful to
make sd_ndisc_router fully descriptive of what it covers.
Fixes: #1079
For it's silly and unnecessary. Although it was apparently mandated by RFC 2462 in [5.5.2. Absence of Router Advertisements], that has been changed in the same section of RFC 4862, which obsoleted the former RFC.
dhcp6_request_address() was merely a function to switch the DHCPv6 client from "stateless" mode to "stateful" mode. It was also a one-way switch. Also, to (re)start the client, we would need to repeat separate function calls.
In this patch, dhcp6_request_address() is made a general starter/manager of the DHCPv6 client. It now takes an extra parameter so we will be specifying which mode the DHCPv6 client should be started in. Also it will keep track of the current mode and compare with the newly requested mode, and only restart the client in case there is a difference between them.
This also makes sure that the DHCPv6 client will be (re)started accordingly as per the Router Advertisement flags.
A field "index" is not particularly precise and also might conflict with libc's
index() function definition. Also, pretty much everywhere else we call this
concept "ifindex", including in networkd, the primary user of these libraries.
Hence, let's fix this up and call this "ifindex" everywhere here too.
Fixup for #3304.
Only warn, and not return, because that's what sd_dhcp6_client_start()
does right below the call to sd_dhcp6_client_set_local_address().
Header files were organized in a way where the includer would add various
typedefs used by the includee before including it, resulting in a tangled
web of dependencies between files.
Replace this with the following logic:
networkd.h
/ \
networkd-link.h \
networkd-ipv4ll.h--\__\
networkd-fdb.h \
networkd-network.h netword-netdev-*.h
networkd-route.h \
networkd-netdev.h
If a pointer to a structure defined in a different header file is needed,
use a typedef line instead of including the whole header.
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
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.
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.
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.
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.
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
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.
