bpf_mptcp_ssk_cast

Signed-off-by: Geliang Tang <[email protected]>

include/uapi/linux/bpf.h

@@ -5795,6 +5795,12 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * void *bpf_mptcp_ssk_cast(void *sk)
+ *	Description
+ *		Dynamically cast a *sk* pointer to a *sock* pointer.
+ *	Return
+ *		*sk* if casting is valid, or **NULL** otherwise.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -6009,6 +6015,7 @@ union bpf_attr {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(mptcp_ssk_cast, 212, ##ctx)			\
 	/* */
 
 /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't

net/mptcp/bpf.c

@@ -281,6 +281,20 @@ static struct bpf_struct_ops bpf_mptcp_pm_ops = {
 
 /* MPTCP BPF packet scheduler */
 
+BPF_CALL_1(bpf_mptcp_ssk_cast, struct sock *, sk)
+{
+	BTF_TYPE_EMIT(struct sock);
+	return (unsigned long)sk;
+}
+
+static const struct bpf_func_proto bpf_mptcp_ssk_cast_proto = {
+	.func		= bpf_mptcp_ssk_cast,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_BTF_ID_OR_NULL,
+	.arg1_type	= ARG_ANYTHING,
+	.ret_btf_id	= &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+};
+
 static const struct bpf_func_proto *
 bpf_mptcp_sched_get_func_proto(enum bpf_func_id func_id,
 			       const struct bpf_prog *prog)
@@ -294,6 +308,8 @@ bpf_mptcp_sched_get_func_proto(enum bpf_func_id func_id,
 		return &bpf_skc_to_tcp6_sock_proto;
 	case BPF_FUNC_skc_to_tcp_sock:
 		return &bpf_skc_to_tcp_sock_proto;
+	case BPF_FUNC_mptcp_ssk_cast:
+		return &bpf_mptcp_ssk_cast_proto;
 	default:
 		return bpf_base_func_proto(func_id, prog);
 	}

tools/include/uapi/linux/bpf.h

@@ -5795,6 +5795,12 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * void *bpf_mptcp_ssk_cast(void *sk)
+ *	Description
+ *		Dynamically cast a *sk* pointer to a *sock* pointer.
+ *	Return
+ *		*sk* if casting is valid, or **NULL** otherwise.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -6009,6 +6015,7 @@ union bpf_attr {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(mptcp_ssk_cast, 212, ##ctx)			\
 	/* */
 
 /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't