tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy 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.

sd-ipv4ll: fix error path if sd-ipv4acd allocation fails Let's make sure the destructor cannot hit the n_ref == 0 case.

siphash24: let siphash24_finalize() and siphash24() return the result directly Rather than passing a pointer to return the result, return it directly from the function calls. Also, return the result in native endianess, and let the callers care about the conversion. For hash tables and bloom filters, we don't care, but in order to keep MAC addresses and DHCP client IDs stable, we explicitly convert to LE.

siphash24: change result argument to uint64_t Change the "out" parameter from uint8_t[8] to uint64_t. On architectures which enforce pointer alignment this fixes crashes when we previously cast an unaligned array to uint64_t*, and on others this should at least improve performance as the compiler now aligns these properly. This also simplifies the code in most cases by getting rid of typecasts. The only place which we can't change is struct duid's en.id, as that is _packed_ and public API, so we can't enforce alignment of the "id" field and have to use memcpy instead.

util-lib: split out allocation calls into alloc-util.[ch]

sd-*.h: clean up exported (or to-be-exported) header files 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.

util-lib: split our string related calls from util.[ch] into its own file string-util.[ch] 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.

sd-ipv4ll: allow initial address to be set explicitly This is useful in case the daemon is restarted and the state of the IPv4LL client should be serialized/deserialized.

sd-ipv4ll: fix namespacing Prefix all exported constants with SD_IPV4LL_* to avoid namespacing conflicts.

sd-ipv4acd: fix namespacing Prefix all exported constants with SD_IPV4ACD to prevent namespacing conflicts.

sd-ipv4ll: do not assert_return when seed == 0 Now that seed is an unsigned and not an array, we do not need to assert on it.

sd-ipv4acd: introduce new library split out from sd-ipv4ll This splits the Address Conflict Detection out of the Link Local library so that we can reuse it for DHCP and static addresses in the future. Implements RFC5227.

sd-ipv4ll: simplify conflict handling Use stop() and start() to drop some pulicate code.

sd-ipv4ll: rework callbacks Firstly, no longer distinguish between STOP and INIT states. Secondly, do not trigger STOP events when calls to sd_ipv4ll_*() fail. The caller is the one who would receive the event and will already know that the call to sd_ipv4ll_*() has failed, so it is redundant. STOP events will now only be triggered by calling sd_ipv4ll_stop() explicitly or by some internal error in the library triggered by receiving a packet or an expiring timeout (i.e., any error that would otherwise not be reported back to the consumer of the library). Lastly, follow CODING_STYLE and always return NULL on unref. Protect from objects being destroyed in callbacks accordingly.

sd-ipv4ll: don't allow changing MAC address whilst running This requires the caller to stop and restart the statemachine if they want to change the MAC address.

sd-ipv4ll: code cleanups Simplify timeout handling.

sd-ipv4ll: remove duplicate packet verification Most packets are filtered out by the BPF, so only check for the parts that may actually differ.

sd-ipv4ll: minor cleanups

sd-ipv4ll: split out on_conflict() from on_packet()

sd-ipv4ll: split run_state_machine() into on_packet() and on_timeout() Simplify the code a bit, no functional change.

sd-ipv4ll: filter out unwanted ARP packets in the kernel We currently process every ARP packet, but we should only care about the ones relating to our IP address. Also rename ipv4ll helpers to apr-utils.[ch], and rework the helpers a bit.

tree-wide: drop {} from one-line if blocks Patch via coccinelle.

network: get rid of more RefCnt usage A follow-up to 3733eec3e292e4ddb4cba5eb8d3bd8cbee7102d8

tree-wide: do not return error codes as bool

sd-event: make sure sd_event_now() cannot fail 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.

shared: add random-util.[ch]

refcnt: refcnt is unsigned, fix comparisons This does not make a difference, but the code was confusing.

sd-event: rename sd_event_source_set_name() to sd_event_source_get_name() To mirror the recent name change of the concept for sd_bus objects, follow the same logic for sd_event_source objects, too.

sd-ipv4ll: name the correct source

sd-event: name event sources used in libraries This should help in debugging failing event sources.

libsystemd-network: use CLOCK_BOOTTIME instead of CLOCK_MONOTONIC where possible The timeouts in the networking library (DHCP lease timeouts and similar) should not be affected by suspend. In the cases where CLOCK_BOOTTIME is not implemented, it is still safe to fallback to CLOCK_MONOTONIC, as the consumers of the library (i.e., networkd) _should_ renew the leases when coming out of suspend.

libnetworkd: add link local tests - Also only allow positive ifindex on both dhcp and ipv4ll [tomegun: the kernel always sets a positive ifindex, but some APIs accept ifindex=0 with various meanings, so we should protect against accidentally passing ifindex=0 along.]

sd-ipv4ll: Add an explicit stop state for IPv4LL Add an explicit stop state for IPv4LL so that the user can stop the IPv4LL client from the callback. When returning from the callback, check also the stop state in order to halt any further protocol processing.

sd-ipv4ll: Add reference counting for IPv4LL Similar to DHCP, the IPv4LL library user can decide to free the LL client any time the callback is called. Guard against freeing the LL client in the callback by introducing proper reference counting. Also update code using the IPv4LL library to properly handle a returned NULL from the notify and stop functions if the IPv4LL client was freed.

networkd: smooth transition from ipv4ll to dhcp address Currently when both ipv4ll and dhcp are enabled, ipv4ll address (if one has been claimed) is removed when dhcp address is aquired. This is not the best thing to do since there might be clients unaware of the removal trying to communicate. This patch provides a smooth transition between ipv4ll and dhcp. If ipv4ll address was claimed [1] before dhcp, address is marked as deprecated. Deprecated address is still a valid address and packets can be received on it but address cannot be selected as a source address. If dhcp lease cannot be extended, then ipv4ll address is marked as valid again. [1] If there is no collision, claiming IPv4LL takes between 4 to 7 seconds.

sd-event: rework API to support CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM, too

sd-ipv4ll/networkd: generate predictable addresses Increase the chance of using the same link local address between reboots. The pseudo random sequence of addresses we attempt is now seeded with data that is very likely to stay the same between reboots, but at the same time be unique to the specific machine/nic. First we try to use the ID_NET_NAME_* data from the udev db combined with the machin-id, which is guaranteed to be unique and persistent, if available. If that is not possible (e.g., in containers where we don't have access to the udev db) we fallback to using the MAC address of the interface, which is guaranteed to be unique, and likely to be persistent. [tomegun: three minor changes: - don't expose HASH_KEY in the siphash24 header - get rid of some compile-warnings (and some casts at the same time), by using uint8_t[8] rather than uint64_t in the api - added commit message]

sd-dhcp-client/sd-ipv4ll: allow mac address to be updated at any time If necessary, restart the clients to deal with a changing mac address at runtime. This will solve the problem of starting clients on bridges before they have received their final MAC address.

util: replace close_nointr_nofail() by a more useful safe_close() safe_close() automatically becomes a NOP when a negative fd is passed, and returns -1 unconditionally. This makes it easy to write lines like this: fd = safe_close(fd); Which will close an fd if it is open, and reset the fd variable correctly. By making use of this new scheme we can drop a > 200 lines of code that was required to test for non-negative fds or to reset the closed fd variable afterwards.

sd-network: IPv4 link-local support [v2] Implements IPv4LL with respect to RFC 3927 (http://tools.ietf.org/rfc/rfc3927.txt) and integrates it with networkd. Majority of the IPv4LL state machine is taken from avahi (http://avahi.org/) project's autoip. IPv4LL can be enabled by IPv4LL=yes under [Network] section of .network file. IPv4LL works independent of DHCP but if DHCP lease is aquired, then LL address will be dropped. [tomegun: removed a trailing newline and a compiler warning]