Similar to free_and_replace. I think this should be uppercase to make it
clear that this is a macro. free_and_replace should probably be uppercased
too.
Don't reset the conflict counter when trying a new pseudo random
address, so that after trying 10 addresses the londer timeout is used in
accordance with the RFC
Fixes#14299.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
A bug exists where the conflict counter is cleared
regardless of whether or not the next probe attempt leads to
a successful address acquisition. This causes 'bursts' of
MAX_CONFLICTS probes followed by a delay of
RATE_LIMIT_INTERVAL instead of a single probe each
RATE_LIMIT_INTERVAL when beyond MAX_CONFLICTS.
The conflict counter should only be cleared after an
address is successfully acquired. This commit achieves that
goal.
From RFC3927:
A host should maintain a counter of the number of address
conflicts it has experienced in the process of trying to
acquire an address, and if the number of conflicts exceeds
MAX_CONFLICTS then the host MUST limit the rate at which it
probes for new addresses to no more than one new address per
RATE_LIMIT_INTERVAL. This is to prevent catastrophic ARP
storms in pathological failure cases, such as a rogue host
that answers all ARP probes, causing legitimate hosts to go
into an infinite loop attempting to select a usable address.
Signed-off-by: Jason Reeder <jasonreeder@gmail.com>
We try to stick to usec_t for encoding time information, do that here too. In
particular, get rid of "int" second specifications, since signed timespans are
a weird thing.
This state is active immediately after the state engine was started, but before
the first timer hits.
This way multiple _start() invocations on the same object are always detected
correctly.
This is much less confusing, since there's also sd_ipv4acd_stop(), which was
idfferent from ipv4acd_stop().
After renaming it, let's also use the funciton when destroying ipv4acd objects,
as the code is pretty much the same for that.
They are counters after all, and can never go below zero, hence don't pretend
with the chose type that they could.
Also, prefix their name with "n_", to indicate that they are counters.
These objects are only useful when multiple threads are involved, as they
operate with atomic operations. Given that our libraries are explicitly not
thread-safe don't make use of RefCnt here, and make things a bit simpler.
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.
This is a follow-up to cf447cb62d.
Let's generally follow the rule to not use read() on SOCK_DGRAM sockets, let's
always use recv() on that.
Also, don't abort IPV4ACD logic in case we read a short packet. Simply log and
ignore.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
