It might very well return EAGAIN in case of packet checksum problems and
suchlike, hence let's better handle this nicely, the same way as we do it in
the other sd-network libraries for incoming datagrams.
Let's make sure the inline functions for retrieving TLV data actually carry TLV
in the name, so that we don#t assume they retrieve the whole, raw packet data.
Let's make sd-lldp a bit more like sd-ndisc ant the other APIs, and add proper
ref counting and a separate call for setting the ifindex.
This also adds a new lldp_reset() call we can use at various places to close
all fds. This is also similar to how sd-ndisc already does it.
It's a good idea to store away the recption time of LLDP packets in the
neighbor object, simply because the LLDP data only has a validity of a certain
amount of time.
Hence, let's record the timestamp when we receive the datagram and expose an
API for it. Also, automatically expire LLDP neighbors based on this new
timestamp.
Let's better check the size before we subtract. Also, let's change the size
argument to size_t, as it cannot be signed anyway.
Finally, use EBADMSG for indicating invalid packets, like we do everywhere
else.
There's no "client" object, in both cases. There's only "nd".
This wasn't noticed before, as the context object is currently not actually
used by the log macros.
Let's make the seed actually work as stable seed, and use siphash24 to generate
the series of addresses, instead of the opaque libc random_r().
This not only makes the seed truly work as stable, portable seed, but also
makes the code quite a bit shorter, and removes a couple of memory allocations.
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.
assert_return() should only be used to validate user-facing parameters and
state, assert() should be used for checking our own internal state and
parameters.
After all, it's actually used for resetting the state, not only for the initial
initialization.
While we are at it, also simplify the error path for
sd_ndisc_discovery_start().
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.
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Thomas Haller
John Paul Adrian Glaubitz