[PATCH bpf-next 2/8] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP

[Jakub Sitnicki <jakub@cloudflare.com>]

Don't require the kernel code, like BPF helpers, that needs access to
SOCKMAP map contents to live in the sock_map module. Expose the SOCKMAP
lookup operation to all kernel-land.

Lookup from BPF context is not whitelisted yet. While syscalls have a
dedicated lookup handler.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 net/core/sock_map.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e8460fdc597d..9f572d56e81a 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -273,7 +273,7 @@ static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
 
 static void *sock_map_lookup(struct bpf_map *map, void *key)
 {
-	return ERR_PTR(-EOPNOTSUPP);
+	return __sock_map_lookup_elem(map, *(u32 *)key);
 }
 
 static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
@@ -899,6 +899,11 @@ static void sock_hash_free(struct bpf_map *map)
 	kfree(htab);
 }
 
+static void *sock_hash_lookup(struct bpf_map *map, void *key)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 static void sock_hash_release_progs(struct bpf_map *map)
 {
 	psock_progs_drop(&container_of(map, struct bpf_htab, map)->progs);
@@ -978,7 +983,7 @@ const struct bpf_map_ops sock_hash_ops = {
 	.map_get_next_key	= sock_hash_get_next_key,
 	.map_update_elem	= sock_hash_update_elem,
 	.map_delete_elem	= sock_hash_delete_elem,
-	.map_lookup_elem	= sock_map_lookup,
+	.map_lookup_elem	= sock_hash_lookup,
 	.map_release_uref	= sock_hash_release_progs,
 	.map_check_btf		= map_check_no_btf,
 };
-- 
2.20.1