include: import linux/io_uring/bpf_filter.h from v7.3-rc2

We need it to register io_uring BPF filters for services.

src/include/uapi/linux/io_uring/bpf_filter.h

@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: (GPL-2.0 WITH Linux-syscall-note) OR MIT */
+/*
+ * Header file for the io_uring BPF filters.
+ */
+#ifndef LINUX_IO_URING_BPF_FILTER_H
+#define LINUX_IO_URING_BPF_FILTER_H
+
+#include <linux/types.h>
+
+/*
+ * Struct passed to filters.
+ */
+struct io_uring_bpf_ctx {
+	__u64	user_data;
+	__u8	opcode;
+	__u8	sqe_flags;
+	__u8	pdu_size;	/* size of aux data for filter */
+	__u8	pad[5];
+	union {
+		struct {
+			__u32	family;
+			__u32	type;
+			__u32	protocol;
+		} socket;
+		struct {
+			__u64	flags;
+			__u64	mode;
+			__u64	resolve;
+		} open;
+		/*
+		 * For CONNECT: fields are populated only when addr_len covers
+		 * them; unpopulated fields are zero from the caller-side memset
+		 * in io_uring_populate_bpf_ctx(). port and v4_addr are network
+		 * byte order. Filters may only issue BPF_LD|BPF_W|BPF_ABS at
+		 * 4-byte aligned offsets; load + mask for sub-word fields.
+		 */
+		struct {
+			__u32	family;	/* sa_family_t zero-extended */
+			__be16	port;
+			__u8	pad[2];
+			union {
+				__be32	v4_addr;
+				__u8	v6_addr[16];
+			};
+		} connect;
+	};
+};
+
+enum {
+	/*
+	 * If set, any currently unset opcode will have a deny filter attached
+	 */
+	IO_URING_BPF_FILTER_DENY_REST	= 1,
+	/*
+	 * If set, if kernel and application don't agree on pdu_size for
+	 * the given opcode, fail the registration of the filter.
+	 */
+	IO_URING_BPF_FILTER_SZ_STRICT	= 2,
+};
+
+struct io_uring_bpf_filter {
+	__u32	opcode;		/* io_uring opcode to filter */
+	__u32	flags;
+	__u32	filter_len;	/* number of BPF instructions */
+	__u8	pdu_size;	/* expected pdu size for opcode */
+	__u8	resv[3];
+	__u64	filter_ptr;	/* pointer to BPF filter */
+	__u64	resv2[5];
+};
+
+enum {
+	IO_URING_BPF_CMD_FILTER	= 1,
+};
+
+struct io_uring_bpf {
+	__u16	cmd_type;	/* IO_URING_BPF_* values */
+	__u16	cmd_flags;	/* none so far */
+	__u32	resv;
+	union {
+		struct io_uring_bpf_filter	filter;
+	};
+};
+
+#endif