linux/tools
Kumar Kartikeya Dwivedi 8bbb77b7c7 libbpf: Add various netlink helpers
This change introduces a few helpers to wrap open coded attribute
preparation in netlink.c. It also adds a libbpf_netlink_send_recv() that
is useful to wrap send + recv handling in a generic way. Subsequent patch
will also use this function for sending and receiving a netlink response.
The libbpf_nl_get_link() helper has been removed instead, moving socket
creation into the newly named libbpf_netlink_send_recv().

Every nested attribute's closure must happen using the helper
nlattr_end_nested(), which sets its length properly. NLA_F_NESTED is
enforced using nlattr_begin_nested() helper. Other simple attributes
can be added directly.

The maxsz parameter corresponds to the size of the request structure
which is being filled in, so for instance with req being:

  struct {
	struct nlmsghdr nh;
	struct tcmsg t;
	char buf[4096];
  } req;

Then, maxsz should be sizeof(req).

This change also converts the open coded attribute preparation with these
helpers. Note that the only failure the internal call to nlattr_add()
could result in the nested helper would be -EMSGSIZE, hence that is what
we return to our caller.

The libbpf_netlink_send_recv() call takes care of opening the socket,
sending the netlink message, receiving the response, potentially invoking
callbacks, and return errors if any, and then finally close the socket.
This allows users to avoid identical socket setup code in different places.
The only user of libbpf_nl_get_link() has been converted to make use of it.
__bpf_set_link_xdp_fd_replace() has also been refactored to use it.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
[ Daniel: major patch cleanup ]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210512103451.989420-2-memxor@gmail.com
2021-05-17 17:48:36 +02:00
..
accounting
arch - turn the stack canary into a normal __percpu variable on 32-bit which 2021-04-27 17:45:09 -07:00
bootconfig tools/bootconfig: Add tracing_on support to helper scripts 2021-01-14 10:32:20 -05:00
bpf bpftool: Stop emitting static variables in BPF skeleton 2021-05-11 15:07:17 -07:00
build perf tools changes for v5.13: 1st batch 2021-05-01 12:22:38 -07:00
cgroup tools/cgroup/slabinfo.py: updated to work on current kernel 2021-04-23 14:42:40 -07:00
debugging tools: Fix a typo in kernel-chktaint 2021-04-08 11:41:22 -06:00
edid
firewire
firmware
gpio tools: gpio-utils: fix various kernel-doc warnings 2021-03-26 14:56:19 +01:00
hv
iio iio: event_monitor: Enable events before monitoring 2021-03-25 19:13:52 +00:00
include Merge branch 'akpm' (patches from Andrew) 2021-05-07 00:34:51 -07:00
io_uring
kvm/kvm_stat tools/kvm_stat: Add restart delay 2021-03-30 13:07:09 -04:00
laptop
leds
lib libbpf: Add various netlink helpers 2021-05-17 17:48:36 +02:00
memory-model doc: update rcu_dereference.rst reference 2021-04-06 14:45:04 +02:00
objtool Objtool updates in this cycle were: 2021-04-28 12:53:24 -07:00
pci
pcmcia
perf perf tools changes for v5.13: 1st batch 2021-05-01 12:22:38 -07:00
power Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2021-05-05 12:24:29 -07:00
scripts tools: disable -Wno-type-limits 2021-05-06 19:24:11 -07:00
spi spi: tools: make a symbolic link to the header file spi.h 2021-04-22 16:30:39 +01:00
testing selftests/bpf: Validate skeleton gen handles skipped fields 2021-05-13 17:23:57 -07:00
thermal/tmon tools: do not include scripts/Kbuild.include 2021-04-25 05:26:13 +09:00
time
tracing tools/latency-collector: Remove unneeded semicolon 2021-03-18 12:58:26 -04:00
usb treewide: remove editor modelines and cruft 2021-05-07 00:26:34 -07:00
virtio tools/virtio: add barrier for aarch64 2020-12-18 16:14:30 -05:00
vm
wmi
Makefile tracing/tools: Add the latency-collector to tools directory 2021-02-12 11:52:59 -05:00