[PATCH] bpf: Allow bpf_get_netns_cookie in BPF_PROG_TYPE_SOCK_OPS

[Xu Liu <liuxu623@gmail.com>]

We'd like to be able to identify netns from sockops hooks
to accelerate local process communication form different netns.

Signed-off-by: Xu Liu <liuxu623@gmail.com>
---
 net/core/filter.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index d70187ce851b..34938a537931 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4664,6 +4664,18 @@ static const struct bpf_func_proto bpf_get_netns_cookie_sock_addr_proto = {
 	.arg1_type	= ARG_PTR_TO_CTX_OR_NULL,
 };
 
+BPF_CALL_1(bpf_get_netns_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
+{
+	return __bpf_get_netns_cookie(ctx ? ctx->sk : NULL);
+}
+
+static const struct bpf_func_proto bpf_get_netns_cookie_sock_ops_proto = {
+	.func		= bpf_get_netns_cookie_sock_ops,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX_OR_NULL,
+};
+
 BPF_CALL_1(bpf_get_socket_uid, struct sk_buff *, skb)
 {
 	struct sock *sk = sk_to_full_sk(skb->sk);
@@ -7445,6 +7457,8 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_sk_storage_get_proto;
 	case BPF_FUNC_sk_storage_delete:
 		return &bpf_sk_storage_delete_proto;
+	case BPF_FUNC_get_netns_cookie:
+		return &bpf_get_netns_cookie_sock_ops_proto;
 #ifdef CONFIG_INET
 	case BPF_FUNC_load_hdr_opt:
 		return &bpf_sock_ops_load_hdr_opt_proto;
-- 
2.28.0