gcc 7 adds -Wimplicit-fallthrough=3 to -Wextra. There are a few ways
we could deal with that. After we take into account the need to stay compatible
with older versions of the compiler (and other compilers), I don't think adding
__attribute__((fallthrough)), even as a macro, is worth the trouble. It sticks
out too much, a comment is just as good. But gcc has some very specific
requiremnts how the comment should look. Adjust it the specific form that it
likes. I don't think the extra stuff we had in those comments was adding much
value.
(Note: the documentation seems to be wrong, and seems to describe a different
pattern from the one that is actually used. I guess either the docs or the code
will have to change before gcc 7 is finalized.)
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.
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.
According to recv(2) these should be the same, but that is not true.
Passing a buffer of length 0 to read is defined to be a noop according
to read(2), but passing a buffer of length 0 to recv will discard the
pending pacet.
We can easily hit this as we allocate our buffer size depending on
the size of the incoming packet (using FIONREAD). As pointed out in
issue #3299 simply sending an empty UDP packet to the DHCP client
port will trigger a busy loop in networkd as we are polling on the
socket but never discarding the empty packet.
This reverts ad5ae47a0d but fixes the
same issue.
Both versions of the code are changed to allow the caller to override
DUID using simple rules: duid type and value may be specified, in
which case the caller is responsible to providing the contents,
or just duid type may be specified as DUID_TYPE_EN, in which case we
we fill in the values. In the future more support for other types may
be added, e.g. DUID_TYPE_LLT.
There still remains and ugly discrepancy between dhcp4 and dhcp6 code:
dhcp6 has sd_dhcp6_client_set_duid and sd_dhcp6_client_set_iaid and
requires client->state to be DHCP6_STATE_STOPPED, while dhcp4 has
sd_dhcp_client_set_iaid_duid and will reconfigure the client if it
is not stopped. This commit doesn't touch that part.
This addresses #3127 § 2.
libsystemd-network provides the public function
sd_dhcp6_client_set_request_option() to enable the request of a given
DHCP option. However the enum defining such options is defined in the
internal header dhcp6-protocol.h. Move the enum definition to the
public header sd-dhcp6-client.h and properly namespace values.
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.
Exported header files should not include internal headers. Fix that.
Exported header files should not use the bool type. So far we opted to
stick to C89 for exported headers, and hence use "int" for bools in
them. Continue to do so.
Exported header files should have #include lines for everything they use
including inttypes.h and sys/types.h, so that they may be included in
any order.
Exported header files should have C++ guards, hence add them.
Exported header files should not use gcc extensions like #pragma once,
get rid of it.
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.
Prevent modifications to index, MAC address, DUID and Information
Request while the DHCPv6 client is running.
Require the DHCPv6 client to be stopped first instead of always
unconditionally restarting it if the caller calls
sd_dhcp6_client_start() more than once. With this change, handling
of for example incoming Router Advertisments becomes much easier.
Factor our common code to set/clear the client lease.
Resetting the lease involves canceling old timers.
Also, most importantly, when resetting the lease
in client_receive_advertise(), ensure to cancel
the timers too. It is not immediately clear, why
at that point no timers would be pending.
The lease-unref from sd_dhcp6_client_unref() can
be omited, because of the preceeding client_reset()
call.
In our API design, getter-functions don't ref objects. Calls like
foo_get_bar() will not ref 'bar'. We never do that and there is no real
reason to do it in single threaded APIs. If you need a ref-count, you
better take it yourself *BEFORE* doing anything else on the parent object
(as this might invalidate your pointer).
Right now, sd_dhcp?_get_lease() refs the lease it returns. A lot of
code-paths in systemd do not expect this and thus leak the lease
reference. Fix this by changing the API to not ref returned objects.
Although the SNTP option specified in RFC 4075 has been deprecated, some
servers are still sending NTP information with this option. Use the SNTP
information provided only if the NTP option is not present.
Update the test case as SNTP information is also requested.
Support DHCPv6 DNS search list option as specified in RFC 3646. This
option contains a list of DNS search domains encoded without compression
as specified in Section 8. of RFC 3315.
When the DHCPv6 client is started by the library user or stopped for
any reason, unref the DHCPv6 lease when resetting the DHCPv6 client
data structure. This makes the DHCPv6 client always start from a clean
state and not keep unnecessary an lease structure around when stopped.
If this is not done, a previously existing lease information can be
interpreted to be from another server when restarting DHCPv6.
Previously, if the event loop never ran before sd_event_now() would
fail. With this change it will instead fall back to invoking now(). This
way, the function cannot fail anymore, except for programming error when
invoking it with wrong parameters.
This takes into account the fact that many callers did not handle the
error condition correctly, and if the callers did, then they kept simply
invoking now() as fall back on their own. Hence let's shorten the code
using this call, and make things more robust, and let's just fall back
to now() internally.
Whether now() is used or the cache timestamp may still be detected via
the return value of sd_event_now(). If > 0 is returned, then the fall
back to now() was used, if == 0 is returned, then the cached value was
returned.
This patch also simplifies many of the invocations of sd_event_now():
the manual fall back to now() can be removed. Also, in cases where the
call is invoked withing void functions we can now protect the invocation
via assert_se(), acknowledging the fact that the call cannot fail
anymore except for programming errors with the parameters.
This change is inspired by #841.
