This makes it more consistent with nettools' lease_to_ip4_config().
The benefit of having a self pointer, is that it provides the necessary
context for logging. Without it, these functions cannot correctly log.
At this point, it's clearer to get the necessary data directly from the
DHCP client instance, instead of having the caller passing them on
(redundantly).
For an IPv4 subnet mask we expect that all the leading bits are set (no
"holes"). But _nm_utils_ip4_netmask_to_prefix() does not enforce that,
and tries to make the best of it.
In face of a netmask with holes, normalize the mask.
We have two variants of the function: nm_utils_ip4_netmask_to_prefix()
and _nm_utils_ip4_netmask_to_prefix(). The former only exists because it
is public API in libnm. Internally, only use the latter.
This was working for internal plugin in the past, but broken by l3cfg
rework with 1.36. Re-add it. Not it also works with dhclient. For other
plugins, it's not really working, because we can't decline.
Now NMDhcpClient does ACD (using NML3Cfg) and abstracts that from
the caller (NMDevice).
It is complicated. Because there is state involved, meaning, we need
to remember the current state for ACD and react on and handle a
multitude of events. Getting this right, is non-trivial.
What we want is that if ACD fails, we decline the lease (and don't use
it).
https://bugzilla.redhat.com/show_bug.cgi?id=1713380
dhclient itself doesn't do ACD. However, it expects the dhclient-script
to exit with non-zero status, which causes dhclient to send a DECLINE.
`man dhclient-script`:
BOUND:
Before actually configuring the address, dhclient-script should
somehow ARP for it and exit with a nonzero status if it receives a
reply. In this case, the client will send a DHCPDECLINE message to
the server and acquire a different address. This may also be done in
the RENEW, REBIND, or REBOOT states, but is not required, and indeed may
not be desirable.
See also Fedora's dhclient-script ([1]).
https://gitlab.isc.org/isc-projects/dhcp/-/issues/67#note_9722633226f2d76/client/dhclient.c (L1652)
[1] a8f6fd046f/f/dhclient-script (_878)https://bugzilla.redhat.com/show_bug.cgi?id=1713380
- assign the result of NM_DHCP_CLIENT_GET_CLASS() to a local variable.
It feels nicer to only call the macro once. Of course, the macro
expands to plain pointer dereferences, so there is little difference
in terms of executed code.
- handle the default case with no virtual function first.
It's pretty pointless to log
<trace> [1653389116.6288] dhcp4 (br0): client event 7
<debug> [1653389116.6288] dhcp4 (br0): received OFFER of 192.168.121.110 from 192.168.121.1
where the obscure event #7 is only telling you that we are going
to log something. Handle logging events first.
In general, drop the "client event %d" message and make sure that all
code paths log something (useful), so we can see in the log that the
event was reached.
When we accept/decline a lease, then that only works if we are in state
GRANTED. n-dhcp4 API also requires us, to provide the exact lease, that
we were announced earlier.
As such, we need to make sure that we don't accept/decline in the wrong
state. That means, to keep track of what we are doing more carefully.
The functions _dhcp_client_accept()/_dhcp_client_decline() now take
a l3cd argument, the one that we announced earlier. And we check that it
still matches.
They are no longer used from outside, NMDhcpClient fully handles this.
Make them static and internal.
Also, decline is currently unused. It will be used soon, with ACD
support.
The same check is also for nettools' n-dhcp4 client. It's useful to
being able to rely on certain things, like that an DHCPv4 lease always
has exactly one address (not equal to 0.0.0.0).
The l3_cfg_notify_cb() handler is used for different purposes, and
different events will be considered.
Usually a switch statement is very nice for enums, especially if all
enum values should be handled (because the compiler can warn about
unhandled cases). In this case, not all events are supposed to be
handled. At this point, it seems nicer to just use an if block. It
better composes.
The compiler should be able to optimize both variants to the same
result. In any case, checking some integers for equality is in any case
going to be efficient.
As almost always, there is a point in keeping IPv4 and IPv6 implementations
similar. Behave different where there is an actual difference, at the bottom
of the stack.
Technically, g_warn_if_reached() may not be an assertion, according to
glib. However, there is G_DEBUG=fatal-warnings and we want to run with
that.
So this is an assertion to us. Also, logging to stderr/stdout is not a
useful thing to the daemon. Don't do this. Especially, since it depends
on user provided (untrusted) input.
Optimally we want stateless, pure code. Obviously, NMDhcpClient needs to
keep state to know what it's doing. However, we should well encapsulate
the state inside NMDhcpClient, and only accept events/notifications that
mutate the internal state according to certain rules.
Having a function public set_state(self, new_state) means that other
components (subclasses of NMDhcpClient) can directly mangle the state.
That means, you no longer need to only reason about the internal state
of NMDhcpClient (and the events/notifications/state-changes that it
implements). You also need to reason that other components take part of
maintaining that internal state.
Rename nm_dhcp_client_set_state() to nm_dhcp_client_notify(). Also, add
a new enum NMDhcpClientEventType with notification/event types.
In practice, this is only renaming. But naming is important, because it
suggests the reader how to think about the code.
The "noop" state is almost unused, however, nm_dhcp_set_state()
has a check "if (new_state >= NM_DHCP_STATE_TIMEOUT)", so the order
of the NOOP state matters.
Fix that by reordering.
Also, just return right away from NOOP.
NMDhcpState is very tied to events from dhclient. But most of these
states we don't care about, and NMDhcpClient definitely should abstract
and hide them.
We should repurpose NMDhcpState to simpler state. For that, first drop
the state from nm_dhcp_client_handle_event().
This is only the first step (which arguably makes the code more
complicated, because reason_to_state() gets spread out and the logic
happens more than once). That will be addressed next.
- return early to avoid nested block.
- use NM_STR_HAS_PREFIX() over g_str_has_prefix(), because that
can be inlined and only accepts a C literal as prefix argument.
- the code comment was unclear/wrong. If something comes from an environment
variables it is *NOT* UTF-8 safe. Also, we convert all non-ASCII characters,
not only non UTF-8 characters.
- as we already convert the string to ASCII, the check whether it's UTF-8
is bogus.
- using GString is unnecessary.
- use NM_IN_STRSET_ASCII_CASE().
- don't use else block after we return.
- don't accept the "iface" argument just for logging. The caller
can do the logging, if they wish.
Log messages when invalid DHCP options are found. For example:
<info> dhcp4 (eth0): error parsing DHCP option 6 (domain_name_servers): address 0.0.0.0 is ignored
<info> dhcp4 (eth0): error parsing DHCP option 12 (host_name): '.example.com' is not a valid DNS domain
<info> dhcp4 (eth0): error parsing DHCP option 26 (interface_mtu): value 60 is smaller than 68
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1225
Instead of logging the event-id, which is composed from options that
are already visible in the log, it's more interesting to log that the
lease was merged.
