xsk: support BPF_EXIST and BPF_NOEXIST flags in XSKMAP
The XSKMAP did not honor the BPF_EXIST/BPF_NOEXIST flags when updating
an entry. This patch addresses that.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 16031d4..4cc28e2 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -226,8 +226,6 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
return -EINVAL;
if (unlikely(i >= m->map.max_entries))
return -E2BIG;
- if (unlikely(map_flags == BPF_NOEXIST))
- return -EEXIST;
sock = sockfd_lookup(fd, &err);
if (!sock)
@@ -257,6 +255,12 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
if (old_xs == xs) {
err = 0;
goto out;
+ } else if (old_xs && map_flags == BPF_NOEXIST) {
+ err = -EEXIST;
+ goto out;
+ } else if (!old_xs && map_flags == BPF_EXIST) {
+ err = -ENOENT;
+ goto out;
}
xsk_map_sock_add(xs, node);
WRITE_ONCE(*map_entry, xs);