bpf: Add xdp load and store helpers

Offering: HULK
hulk inclusion
category: feature
bugzilla: N/A

--------------------------------

Add sample helper to store bytes to XDP buffer and load bytes from XDP
buffer.
Signed-off-by: NXu Kuohai <xukuohai@huawei.com>

include/uapi/linux/bpf.h

@@ -4056,6 +4056,20 @@ union bpf_attr {
  *             Update tcp seq
  *     Return
  *             0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_store_bytes(struct xdp_buff *ctx, u32 offset, const void *from, u32 len)
+ *     Description
+ *             store *len* bytes from address *from* into xdp buffer *ctx*, at
+ *             *offset*
+ *     Return
+ *             0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_load_bytes(struct xdp_buff *ctx, u32 offset, void *to, u32 len)
+ *     Description
+ *             load *len* bytes to address *to* from xdp buffer *ctx*, at
+ *             *offset*
+ *     Return
+ *             0 on success, or a negative error in case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -4242,6 +4256,8 @@ union bpf_attr {
 	FN(sys_close),			\
 	FN(kallsyms_lookup_name),	\
 	FN(update_tcp_seq),		\
+	FN(xdp_store_bytes),		\
+	FN(xdp_load_bytes),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

net/core/filter.c

@@ -6287,6 +6287,50 @@ static const struct bpf_func_proto bpf_xdp_update_tcp_seq_proto = {
 	.arg5_type      = ARG_ANYTHING,
 };
 
+BPF_CALL_4(bpf_xdp_store_bytes, struct xdp_buff *, xdp, u32, offset,
+	   const void *, from, u32, len)
+{
+	if (unlikely(offset > xdp->data_end - xdp->data ||
+		     len > xdp->data_end - xdp->data - offset))
+		return -EINVAL;
+
+	memmove(xdp->data + offset, from, len);
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_xdp_store_bytes_proto = {
+	.func		= bpf_xdp_store_bytes,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_xdp_load_bytes, struct xdp_buff *, xdp, u32, offset,
+	   void *, to, u32, len)
+{
+	if (unlikely(offset > xdp->data_end - xdp->data ||
+		     len > xdp->data_end - xdp->data - offset))
+		return -EINVAL;
+
+	memmove(to, xdp->data + offset, len);
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_xdp_load_bytes_proto = {
+	.func		= bpf_xdp_load_bytes,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_5(bpf_sock_addr_skc_lookup_tcp, struct bpf_sock_addr_kern *, ctx,
 	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
 {
@@ -7376,6 +7420,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_tcp_gen_syncookie:
 		return &bpf_tcp_gen_syncookie_proto;
 #endif
+	case BPF_FUNC_xdp_store_bytes:
+		return &bpf_xdp_store_bytes_proto;
+	case BPF_FUNC_xdp_load_bytes:
+		return &bpf_xdp_load_bytes_proto;
 	default:
 		return bpf_sk_base_func_proto(func_id);
 	}

tools/include/uapi/linux/bpf.h

@@ -4766,6 +4766,20 @@ union bpf_attr {
  *             Update tcp seq
  *     Return
  *             0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_store_bytes(struct xdp_buff *ctx, u32 offset, const void *from, u32 len)
+ *     Description
+ *             store *len* bytes from address *from* into xdp buffer *ctx*, at
+ *             *offset*
+ *     Return
+ *             0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_load_bytes(struct xdp_buff *ctx, u32 offset, void *to, u32 len)
+ *     Description
+ *             load *len* bytes to address *to* from xdp buffer *ctx*, at
+ *             *offset*
+ *     Return
+ *             0 on success, or a negative error in case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -4952,6 +4966,8 @@ union bpf_attr {
 	FN(sys_close),			\
 	FN(kallsyms_lookup_name),	\
 	FN(update_tcp_seq),		\
+	FN(xdp_store_bytes),		\
+	FN(xdp_load_bytes),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper