linux-stable/net/xdp
Björn Töpel ee75aef23a bpf, xdp: Restructure redirect actions
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.

Here, the map type and id are added to bpf_redirect_info, instead of
the actual map. Map type, map item/ifindex, and the map_id (if any) is
passed to xdp_do_redirect().

For ifindex-based redirect, used by the bpf_redirect() XDP BFP helper,
a special map type/id are used. Map type of UNSPEC together with map id
equal to INT_MAX has the special meaning of an ifindex based
redirect. Note that valid map ids are 1 inclusive, INT_MAX exclusive
([1,INT_MAX[).

In addition to making the code easier to follow, using explicit type
and id in bpf_redirect_info has a slight positive performance impact
by avoiding a pointer indirection for the map type lookup, and instead
use the cacheline for bpf_redirect_info.

Since the actual map is not passed via bpf_redirect_info anymore, the
map lookup is only done in the BPF helper. This means that the
bpf_clear_redirect_map() function can be removed. The actual map item
is RCU protected.

The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210308112907.559576-3-bjorn.topel@gmail.com
2021-03-10 01:06:34 +01:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile xsk: Introduce AF_XDP buffer allocation API 2020-05-21 17:31:26 -07:00
xdp_umem.c xsk: Fix umem cleanup bug at socket destruct 2020-11-20 15:52:39 +01:00
xdp_umem.h xsk: Fix umem cleanup bug at socket destruct 2020-11-20 15:52:39 +01:00
xsk.c xsk: Build skb by page (aka generic zerocopy xmit) 2021-02-25 00:56:43 +01:00
xsk.h xdp: Remove the functions xsk_map_inc and xsk_map_put 2020-11-27 23:00:51 +01:00
xsk_buff_pool.c xsk: Fold xp_assign_dev and __xp_assign_dev 2021-01-25 23:56:33 +01:00
xsk_diag.c xsk: Fix possible segfault in xsk umem diagnostics 2020-09-02 16:49:40 +02:00
xsk_queue.c xsk: Remove MEM_TYPE_ZERO_COPY and corresponding code 2020-05-21 17:31:27 -07:00
xsk_queue.h xsk: Update rings for load-acquire/store-release barriers 2021-03-08 08:52:05 -08:00
xskmap.c bpf, xdp: Restructure redirect actions 2021-03-10 01:06:34 +01:00