bpf: Allow bpf_get_netns_cookie in BPF_PROG_TYPE_SK_MSG

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

Signed-off-by: Xu Liu <liuxu623@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210820071712.52852-2-liuxu623@gmail.com

diff --git a/net/core/filter.c b/net/core/filter.c
index 59b8f50..cfbd011 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4688,6 +4688,18 @@ static const struct bpf_func_proto bpf_get_netns_cookie_sock_ops_proto = {
        .arg1_type      = ARG_PTR_TO_CTX_OR_NULL,
 };
 
+BPF_CALL_1(bpf_get_netns_cookie_sk_msg, struct sk_msg *, ctx)
+{
+       return __bpf_get_netns_cookie(ctx ? ctx->sk : NULL);
+}
+
+static const struct bpf_func_proto bpf_get_netns_cookie_sk_msg_proto = {
+       .func           = bpf_get_netns_cookie_sk_msg,
+       .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);
@@ -7551,6 +7563,8 @@ sk_msg_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_sk_msg_proto;
 #ifdef CONFIG_CGROUPS
        case BPF_FUNC_get_current_cgroup_id:
                return &bpf_get_current_cgroup_id_proto;