T5286: drop XDP support for ethernet and bonding interfaces

... this is a step towards a new and better implementation that will utilize
VPP.

1 files changed, 0 insertions, 3278 deletions

diff --git a/src/xdp/include/linux/bpf.h b/src/xdp/include/linux/bpf.h
deleted file mode 100644
index 161a93809..000000000
--- a/src/xdp/include/linux/bpf.h
+++ /dev/null
@@ -1,3278 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- */
-#ifndef _UAPI__LINUX_BPF_H__
-#define _UAPI__LINUX_BPF_H__
-
-#include <linux/types.h>
-#include <linux/bpf_common.h>
-
-/* Extended instruction set based on top of classic BPF */
-
-/* instruction classes */
-#define BPF_JMP32	0x06	/* jmp mode in word width */
-#define BPF_ALU64	0x07	/* alu mode in double word width */
-
-/* ld/ldx fields */
-#define BPF_DW		0x18	/* double word (64-bit) */
-#define BPF_XADD	0xc0	/* exclusive add */
-
-/* alu/jmp fields */
-#define BPF_MOV		0xb0	/* mov reg to reg */
-#define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
-
-/* change endianness of a register */
-#define BPF_END		0xd0	/* flags for endianness conversion: */
-#define BPF_TO_LE	0x00	/* convert to little-endian */
-#define BPF_TO_BE	0x08	/* convert to big-endian */
-#define BPF_FROM_LE	BPF_TO_LE
-#define BPF_FROM_BE	BPF_TO_BE
-
-/* jmp encodings */
-#define BPF_JNE		0x50	/* jump != */
-#define BPF_JLT		0xa0	/* LT is unsigned, '<' */
-#define BPF_JLE		0xb0	/* LE is unsigned, '<=' */
-#define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
-#define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
-#define BPF_JSLT	0xc0	/* SLT is signed, '<' */
-#define BPF_JSLE	0xd0	/* SLE is signed, '<=' */
-#define BPF_CALL	0x80	/* function call */
-#define BPF_EXIT	0x90	/* function return */
-
-/* Register numbers */
-enum {
-	BPF_REG_0 = 0,
-	BPF_REG_1,
-	BPF_REG_2,
-	BPF_REG_3,
-	BPF_REG_4,
-	BPF_REG_5,
-	BPF_REG_6,
-	BPF_REG_7,
-	BPF_REG_8,
-	BPF_REG_9,
-	BPF_REG_10,
-	__MAX_BPF_REG,
-};
-
-/* BPF has 10 general purpose 64-bit registers and stack frame. */
-#define MAX_BPF_REG	__MAX_BPF_REG
-
-struct bpf_insn {
-	__u8	code;		/* opcode */
-	__u8	dst_reg:4;	/* dest register */
-	__u8	src_reg:4;	/* source register */
-	__s16	off;		/* signed offset */
-	__s32	imm;		/* signed immediate constant */
-};
-
-/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
-struct bpf_lpm_trie_key {
-	__u32	prefixlen;	/* up to 32 for AF_INET, 128 for AF_INET6 */
-	__u8	data[0];	/* Arbitrary size */
-};
-
-struct bpf_cgroup_storage_key {
-	__u64	cgroup_inode_id;	/* cgroup inode id */
-	__u32	attach_type;		/* program attach type */
-};
-
-/* BPF syscall commands, see bpf(2) man-page for details. */
-enum bpf_cmd {
-	BPF_MAP_CREATE,
-	BPF_MAP_LOOKUP_ELEM,
-	BPF_MAP_UPDATE_ELEM,
-	BPF_MAP_DELETE_ELEM,
-	BPF_MAP_GET_NEXT_KEY,
-	BPF_PROG_LOAD,
-	BPF_OBJ_PIN,
-	BPF_OBJ_GET,
-	BPF_PROG_ATTACH,
-	BPF_PROG_DETACH,
-	BPF_PROG_TEST_RUN,
-	BPF_PROG_GET_NEXT_ID,
-	BPF_MAP_GET_NEXT_ID,
-	BPF_PROG_GET_FD_BY_ID,
-	BPF_MAP_GET_FD_BY_ID,
-	BPF_OBJ_GET_INFO_BY_FD,
-	BPF_PROG_QUERY,
-	BPF_RAW_TRACEPOINT_OPEN,
-	BPF_BTF_LOAD,
-	BPF_BTF_GET_FD_BY_ID,
-	BPF_TASK_FD_QUERY,
-	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
-};
-
-enum bpf_map_type {
-	BPF_MAP_TYPE_UNSPEC,
-	BPF_MAP_TYPE_HASH,
-	BPF_MAP_TYPE_ARRAY,
-	BPF_MAP_TYPE_PROG_ARRAY,
-	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
-	BPF_MAP_TYPE_PERCPU_HASH,
-	BPF_MAP_TYPE_PERCPU_ARRAY,
-	BPF_MAP_TYPE_STACK_TRACE,
-	BPF_MAP_TYPE_CGROUP_ARRAY,
-	BPF_MAP_TYPE_LRU_HASH,
-	BPF_MAP_TYPE_LRU_PERCPU_HASH,
-	BPF_MAP_TYPE_LPM_TRIE,
-	BPF_MAP_TYPE_ARRAY_OF_MAPS,
-	BPF_MAP_TYPE_HASH_OF_MAPS,
-	BPF_MAP_TYPE_DEVMAP,
-	BPF_MAP_TYPE_SOCKMAP,
-	BPF_MAP_TYPE_CPUMAP,
-	BPF_MAP_TYPE_XSKMAP,
-	BPF_MAP_TYPE_SOCKHASH,
-	BPF_MAP_TYPE_CGROUP_STORAGE,
-	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
-	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
-	BPF_MAP_TYPE_QUEUE,
-	BPF_MAP_TYPE_STACK,
-};
-
-/* Note that tracing related programs such as
- * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
- * are not subject to a stable API since kernel internal data
- * structures can change from release to release and may
- * therefore break existing tracing BPF programs. Tracing BPF
- * programs correspond to /a/ specific kernel which is to be
- * analyzed, and not /a/ specific kernel /and/ all future ones.
- */
-enum bpf_prog_type {
-	BPF_PROG_TYPE_UNSPEC,
-	BPF_PROG_TYPE_SOCKET_FILTER,
-	BPF_PROG_TYPE_KPROBE,
-	BPF_PROG_TYPE_SCHED_CLS,
-	BPF_PROG_TYPE_SCHED_ACT,
-	BPF_PROG_TYPE_TRACEPOINT,
-	BPF_PROG_TYPE_XDP,
-	BPF_PROG_TYPE_PERF_EVENT,
-	BPF_PROG_TYPE_CGROUP_SKB,
-	BPF_PROG_TYPE_CGROUP_SOCK,
-	BPF_PROG_TYPE_LWT_IN,
-	BPF_PROG_TYPE_LWT_OUT,
-	BPF_PROG_TYPE_LWT_XMIT,
-	BPF_PROG_TYPE_SOCK_OPS,
-	BPF_PROG_TYPE_SK_SKB,
-	BPF_PROG_TYPE_CGROUP_DEVICE,
-	BPF_PROG_TYPE_SK_MSG,
-	BPF_PROG_TYPE_RAW_TRACEPOINT,
-	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-	BPF_PROG_TYPE_LWT_SEG6LOCAL,
-	BPF_PROG_TYPE_LIRC_MODE2,
-	BPF_PROG_TYPE_SK_REUSEPORT,
-	BPF_PROG_TYPE_FLOW_DISSECTOR,
-};
-
-enum bpf_attach_type {
-	BPF_CGROUP_INET_INGRESS,
-	BPF_CGROUP_INET_EGRESS,
-	BPF_CGROUP_INET_SOCK_CREATE,
-	BPF_CGROUP_SOCK_OPS,
-	BPF_SK_SKB_STREAM_PARSER,
-	BPF_SK_SKB_STREAM_VERDICT,
-	BPF_CGROUP_DEVICE,
-	BPF_SK_MSG_VERDICT,
-	BPF_CGROUP_INET4_BIND,
-	BPF_CGROUP_INET6_BIND,
-	BPF_CGROUP_INET4_CONNECT,
-	BPF_CGROUP_INET6_CONNECT,
-	BPF_CGROUP_INET4_POST_BIND,
-	BPF_CGROUP_INET6_POST_BIND,
-	BPF_CGROUP_UDP4_SENDMSG,
-	BPF_CGROUP_UDP6_SENDMSG,
-	BPF_LIRC_MODE2,
-	BPF_FLOW_DISSECTOR,
-	__MAX_BPF_ATTACH_TYPE
-};
-
-#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
-
-/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
- *
- * NONE(default): No further bpf programs allowed in the subtree.
- *
- * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
- * the program in this cgroup yields to sub-cgroup program.
- *
- * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
- * that cgroup program gets run in addition to the program in this cgroup.
- *
- * Only one program is allowed to be attached to a cgroup with
- * NONE or BPF_F_ALLOW_OVERRIDE flag.
- * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
- * release old program and attach the new one. Attach flags has to match.
- *
- * Multiple programs are allowed to be attached to a cgroup with
- * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
- * (those that were attached first, run first)
- * The programs of sub-cgroup are executed first, then programs of
- * this cgroup and then programs of parent cgroup.
- * When children program makes decision (like picking TCP CA or sock bind)
- * parent program has a chance to override it.
- *
- * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
- * A cgroup with NONE doesn't allow any programs in sub-cgroups.
- * Ex1:
- * cgrp1 (MULTI progs A, B) ->
- *    cgrp2 (OVERRIDE prog C) ->
- *      cgrp3 (MULTI prog D) ->
- *        cgrp4 (OVERRIDE prog E) ->
- *          cgrp5 (NONE prog F)
- * the event in cgrp5 triggers execution of F,D,A,B in that order.
- * if prog F is detached, the execution is E,D,A,B
- * if prog F and D are detached, the execution is E,A,B
- * if prog F, E and D are detached, the execution is C,A,B
- *
- * All eligible programs are executed regardless of return code from
- * earlier programs.
- */
-#define BPF_F_ALLOW_OVERRIDE	(1U << 0)
-#define BPF_F_ALLOW_MULTI	(1U << 1)
-
-/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
- * verifier will perform strict alignment checking as if the kernel
- * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
- * and NET_IP_ALIGN defined to 2.
- */
-#define BPF_F_STRICT_ALIGNMENT	(1U << 0)
-
-/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
- * verifier will allow any alignment whatsoever.  On platforms
- * with strict alignment requirements for loads ands stores (such
- * as sparc and mips) the verifier validates that all loads and
- * stores provably follow this requirement.  This flag turns that
- * checking and enforcement off.
- *
- * It is mostly used for testing when we want to validate the
- * context and memory access aspects of the verifier, but because
- * of an unaligned access the alignment check would trigger before
- * the one we are interested in.
- */
-#define BPF_F_ANY_ALIGNMENT	(1U << 1)
-
-/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
-#define BPF_PSEUDO_MAP_FD	1
-
-/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
- * offset to another bpf function
- */
-#define BPF_PSEUDO_CALL		1
-
-/* flags for BPF_MAP_UPDATE_ELEM command */
-#define BPF_ANY		0 /* create new element or update existing */
-#define BPF_NOEXIST	1 /* create new element if it didn't exist */
-#define BPF_EXIST	2 /* update existing element */
-#define BPF_F_LOCK	4 /* spin_lock-ed map_lookup/map_update */
-
-/* flags for BPF_MAP_CREATE command */
-#define BPF_F_NO_PREALLOC	(1U << 0)
-/* Instead of having one common LRU list in the
- * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
- * which can scale and perform better.
- * Note, the LRU nodes (including free nodes) cannot be moved
- * across different LRU lists.
- */
-#define BPF_F_NO_COMMON_LRU	(1U << 1)
-/* Specify numa node during map creation */
-#define BPF_F_NUMA_NODE		(1U << 2)
-
-#define BPF_OBJ_NAME_LEN 16U
-
-/* Flags for accessing BPF object */
-#define BPF_F_RDONLY		(1U << 3)
-#define BPF_F_WRONLY		(1U << 4)
-
-/* Flag for stack_map, store build_id+offset instead of pointer */
-#define BPF_F_STACK_BUILD_ID	(1U << 5)
-
-/* Zero-initialize hash function seed. This should only be used for testing. */
-#define BPF_F_ZERO_SEED		(1U << 6)
-
-/* flags for BPF_PROG_QUERY */
-#define BPF_F_QUERY_EFFECTIVE	(1U << 0)
-
-enum bpf_stack_build_id_status {
-	/* user space need an empty entry to identify end of a trace */
-	BPF_STACK_BUILD_ID_EMPTY = 0,
-	/* with valid build_id and offset */
-	BPF_STACK_BUILD_ID_VALID = 1,
-	/* couldn't get build_id, fallback to ip */
-	BPF_STACK_BUILD_ID_IP = 2,
-};
-
-#define BPF_BUILD_ID_SIZE 20
-struct bpf_stack_build_id {
-	__s32		status;
-	unsigned char	build_id[BPF_BUILD_ID_SIZE];
-	union {
-		__u64	offset;
-		__u64	ip;
-	};
-};
-
-union bpf_attr {
-	struct { /* anonymous struct used by BPF_MAP_CREATE command */
-		__u32	map_type;	/* one of enum bpf_map_type */
-		__u32	key_size;	/* size of key in bytes */
-		__u32	value_size;	/* size of value in bytes */
-		__u32	max_entries;	/* max number of entries in a map */
-		__u32	map_flags;	/* BPF_MAP_CREATE related
-					 * flags defined above.
-					 */
-		__u32	inner_map_fd;	/* fd pointing to the inner map */
-		__u32	numa_node;	/* numa node (effective only if
-					 * BPF_F_NUMA_NODE is set).
-					 */
-		char	map_name[BPF_OBJ_NAME_LEN];
-		__u32	map_ifindex;	/* ifindex of netdev to create on */
-		__u32	btf_fd;		/* fd pointing to a BTF type data */
-		__u32	btf_key_type_id;	/* BTF type_id of the key */
-		__u32	btf_value_type_id;	/* BTF type_id of the value */
-	};
-
-	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
-		__u32		map_fd;
-		__aligned_u64	key;
-		union {
-			__aligned_u64 value;
-			__aligned_u64 next_key;
-		};
-		__u64		flags;
-	};
-
-	struct { /* anonymous struct used by BPF_PROG_LOAD command */
-		__u32		prog_type;	/* one of enum bpf_prog_type */
-		__u32		insn_cnt;
-		__aligned_u64	insns;
-		__aligned_u64	license;
-		__u32		log_level;	/* verbosity level of verifier */
-		__u32		log_size;	/* size of user buffer */
-		__aligned_u64	log_buf;	/* user supplied buffer */
-		__u32		kern_version;	/* not used */
-		__u32		prog_flags;
-		char		prog_name[BPF_OBJ_NAME_LEN];
-		__u32		prog_ifindex;	/* ifindex of netdev to prep for */
-		/* For some prog types expected attach type must be known at
-		 * load time to verify attach type specific parts of prog
-		 * (context accesses, allowed helpers, etc).
-		 */
-		__u32		expected_attach_type;
-		__u32		prog_btf_fd;	/* fd pointing to BTF type data */
-		__u32		func_info_rec_size;	/* userspace bpf_func_info size */
-		__aligned_u64	func_info;	/* func info */
-		__u32		func_info_cnt;	/* number of bpf_func_info records */
-		__u32		line_info_rec_size;	/* userspace bpf_line_info size */
-		__aligned_u64	line_info;	/* line info */
-		__u32		line_info_cnt;	/* number of bpf_line_info records */
-	};
-
-	struct { /* anonymous struct used by BPF_OBJ_* commands */
-		__aligned_u64	pathname;
-		__u32		bpf_fd;
-		__u32		file_flags;
-	};
-
-	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
-		__u32		target_fd;	/* container object to attach to */
-		__u32		attach_bpf_fd;	/* eBPF program to attach */
-		__u32		attach_type;
-		__u32		attach_flags;
-	};
-
-	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
-		__u32		prog_fd;
-		__u32		retval;
-		__u32		data_size_in;	/* input: len of data_in */
-		__u32		data_size_out;	/* input/output: len of data_out
-						 *   returns ENOSPC if data_out
-						 *   is too small.
-						 */
-		__aligned_u64	data_in;
-		__aligned_u64	data_out;
-		__u32		repeat;
-		__u32		duration;
-	} test;
-
-	struct { /* anonymous struct used by BPF_*_GET_*_ID */
-		union {
-			__u32		start_id;
-			__u32		prog_id;
-			__u32		map_id;
-			__u32		btf_id;
-		};
-		__u32		next_id;
-		__u32		open_flags;
-	};
-
-	struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
-		__u32		bpf_fd;
-		__u32		info_len;
-		__aligned_u64	info;
-	} info;
-
-	struct { /* anonymous struct used by BPF_PROG_QUERY command */
-		__u32		target_fd;	/* container object to query */
-		__u32		attach_type;
-		__u32		query_flags;
-		__u32		attach_flags;
-		__aligned_u64	prog_ids;
-		__u32		prog_cnt;
-	} query;
-
-	struct {
-		__u64 name;
-		__u32 prog_fd;
-	} raw_tracepoint;
-
-	struct { /* anonymous struct for BPF_BTF_LOAD */
-		__aligned_u64	btf;
-		__aligned_u64	btf_log_buf;
-		__u32		btf_size;
-		__u32		btf_log_size;
-		__u32		btf_log_level;
-	};
-
-	struct {
-		__u32		pid;		/* input: pid */
-		__u32		fd;		/* input: fd */
-		__u32		flags;		/* input: flags */
-		__u32		buf_len;	/* input/output: buf len */
-		__aligned_u64	buf;		/* input/output:
-						 *   tp_name for tracepoint
-						 *   symbol for kprobe
-						 *   filename for uprobe
-						 */
-		__u32		prog_id;	/* output: prod_id */
-		__u32		fd_type;	/* output: BPF_FD_TYPE_* */
-		__u64		probe_offset;	/* output: probe_offset */
-		__u64		probe_addr;	/* output: probe_addr */
-	} task_fd_query;
-} __attribute__((aligned(8)));
-
-/* The description below is an attempt at providing documentation to eBPF
- * developers about the multiple available eBPF helper functions. It can be
- * parsed and used to produce a manual page. The workflow is the following,
- * and requires the rst2man utility:
- *
- *     $ ./scripts/bpf_helpers_doc.py \
- *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
- *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
- *     $ man /tmp/bpf-helpers.7
- *
- * Note that in order to produce this external documentation, some RST
- * formatting is used in the descriptions to get "bold" and "italics" in
- * manual pages. Also note that the few trailing white spaces are
- * intentional, removing them would break paragraphs for rst2man.
- *
- * Start of BPF helper function descriptions:
- *
- * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
- * 	Description
- * 		Perform a lookup in *map* for an entry associated to *key*.
- * 	Return
- * 		Map value associated to *key*, or **NULL** if no entry was
- * 		found.
- *
- * int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
- * 	Description
- * 		Add or update the value of the entry associated to *key* in
- * 		*map* with *value*. *flags* is one of:
- *
- * 		**BPF_NOEXIST**
- * 			The entry for *key* must not exist in the map.
- * 		**BPF_EXIST**
- * 			The entry for *key* must already exist in the map.
- * 		**BPF_ANY**
- * 			No condition on the existence of the entry for *key*.
- *
- * 		Flag value **BPF_NOEXIST** cannot be used for maps of types
- * 		**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
- * 		elements always exist), the helper would return an error.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_map_delete_elem(struct bpf_map *map, const void *key)
- * 	Description
- * 		Delete entry with *key* from *map*.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_probe_read(void *dst, u32 size, const void *src)
- * 	Description
- * 		For tracing programs, safely attempt to read *size* bytes from
- * 		address *src* and store the data in *dst*.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * u64 bpf_ktime_get_ns(void)
- * 	Description
- * 		Return the time elapsed since system boot, in nanoseconds.
- * 	Return
- * 		Current *ktime*.
- *
- * int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
- * 	Description
- * 		This helper is a "printk()-like" facility for debugging. It
- * 		prints a message defined by format *fmt* (of size *fmt_size*)
- * 		to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
- * 		available. It can take up to three additional **u64**
- * 		arguments (as an eBPF helpers, the total number of arguments is
- * 		limited to five).
- *
- * 		Each time the helper is called, it appends a line to the trace.
- * 		The format of the trace is customizable, and the exact output
- * 		one will get depends on the options set in
- * 		*\/sys/kernel/debug/tracing/trace_options* (see also the
- * 		*README* file under the same directory). However, it usually
- * 		defaults to something like:
- *
- * 		::
- *
- * 			telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
- *
- * 		In the above:
- *
- * 			* ``telnet`` is the name of the current task.
- * 			* ``470`` is the PID of the current task.
- * 			* ``001`` is the CPU number on which the task is
- * 			  running.
- * 			* In ``.N..``, each character refers to a set of
- * 			  options (whether irqs are enabled, scheduling
- * 			  options, whether hard/softirqs are running, level of
- * 			  preempt_disabled respectively). **N** means that
- * 			  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
- * 			  are set.
- * 			* ``419421.045894`` is a timestamp.
- * 			* ``0x00000001`` is a fake value used by BPF for the
- * 			  instruction pointer register.
- * 			* ``<formatted msg>`` is the message formatted with
- * 			  *fmt*.
- *
- * 		The conversion specifiers supported by *fmt* are similar, but
- * 		more limited than for printk(). They are **%d**, **%i**,
- * 		**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
- * 		**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
- * 		of field, padding with zeroes, etc.) is available, and the
- * 		helper will return **-EINVAL** (but print nothing) if it
- * 		encounters an unknown specifier.
- *
- * 		Also, note that **bpf_trace_printk**\ () is slow, and should
- * 		only be used for debugging purposes. For this reason, a notice
- * 		bloc (spanning several lines) is printed to kernel logs and
- * 		states that the helper should not be used "for production use"
- * 		the first time this helper is used (or more precisely, when
- * 		**trace_printk**\ () buffers are allocated). For passing values
- * 		to user space, perf events should be preferred.
- * 	Return
- * 		The number of bytes written to the buffer, or a negative error
- * 		in case of failure.
- *
- * u32 bpf_get_prandom_u32(void)
- * 	Description
- * 		Get a pseudo-random number.
- *
- * 		From a security point of view, this helper uses its own
- * 		pseudo-random internal state, and cannot be used to infer the
- * 		seed of other random functions in the kernel. However, it is
- * 		essential to note that the generator used by the helper is not
- * 		cryptographically secure.
- * 	Return
- * 		A random 32-bit unsigned value.
- *
- * u32 bpf_get_smp_processor_id(void)
- * 	Description
- * 		Get the SMP (symmetric multiprocessing) processor id. Note that
- * 		all programs run with preemption disabled, which means that the
- * 		SMP processor id is stable during all the execution of the
- * 		program.
- * 	Return
- * 		The SMP id of the processor running the program.
- *
- * int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
- * 	Description
- * 		Store *len* bytes from address *from* into the packet
- * 		associated to *skb*, at *offset*. *flags* are a combination of
- * 		**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
- * 		checksum for the packet after storing the bytes) and
- * 		**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
- * 		**->swhash** and *skb*\ **->l4hash** to 0).
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
- * 	Description
- * 		Recompute the layer 3 (e.g. IP) checksum for the packet
- * 		associated to *skb*. Computation is incremental, so the helper
- * 		must know the former value of the header field that was
- * 		modified (*from*), the new value of this field (*to*), and the
- * 		number of bytes (2 or 4) for this field, stored in *size*.
- * 		Alternatively, it is possible to store the difference between
- * 		the previous and the new values of the header field in *to*, by
- * 		setting *from* and *size* to 0. For both methods, *offset*
- * 		indicates the location of the IP checksum within the packet.
- *
- * 		This helper works in combination with **bpf_csum_diff**\ (),
- * 		which does not update the checksum in-place, but offers more
- * 		flexibility and can handle sizes larger than 2 or 4 for the
- * 		checksum to update.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
- * 	Description
- * 		Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
- * 		packet associated to *skb*. Computation is incremental, so the
- * 		helper must know the former value of the header field that was
- * 		modified (*from*), the new value of this field (*to*), and the
- * 		number of bytes (2 or 4) for this field, stored on the lowest
- * 		four bits of *flags*. Alternatively, it is possible to store
- * 		the difference between the previous and the new values of the
- * 		header field in *to*, by setting *from* and the four lowest
- * 		bits of *flags* to 0. For both methods, *offset* indicates the
- * 		location of the IP checksum within the packet. In addition to
- * 		the size of the field, *flags* can be added (bitwise OR) actual
- * 		flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
- * 		untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
- * 		for updates resulting in a null checksum the value is set to
- * 		**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
- * 		the checksum is to be computed against a pseudo-header.
- *
- * 		This helper works in combination with **bpf_csum_diff**\ (),
- * 		which does not update the checksum in-place, but offers more
- * 		flexibility and can handle sizes larger than 2 or 4 for the
- * 		checksum to update.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
- * 	Description
- * 		This special helper is used to trigger a "tail call", or in
- * 		other words, to jump into another eBPF program. The same stack
- * 		frame is used (but values on stack and in registers for the
- * 		caller are not accessible to the callee). This mechanism allows
- * 		for program chaining, either for raising the maximum number of
- * 		available eBPF instructions, or to execute given programs in
- * 		conditional blocks. For security reasons, there is an upper
- * 		limit to the number of successive tail calls that can be
- * 		performed.
- *
- * 		Upon call of this helper, the program attempts to jump into a
- * 		program referenced at index *index* in *prog_array_map*, a
- * 		special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
- * 		*ctx*, a pointer to the context.
- *
- * 		If the call succeeds, the kernel immediately runs the first
- * 		instruction of the new program. This is not a function call,
- * 		and it never returns to the previous program. If the call
- * 		fails, then the helper has no effect, and the caller continues
- * 		to run its subsequent instructions. A call can fail if the
- * 		destination program for the jump does not exist (i.e. *index*
- * 		is superior to the number of entries in *prog_array_map*), or
- * 		if the maximum number of tail calls has been reached for this
- * 		chain of programs. This limit is defined in the kernel by the
- * 		macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
- * 		which is currently set to 32.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
- * 	Description
- * 		Clone and redirect the packet associated to *skb* to another
- * 		net device of index *ifindex*. Both ingress and egress
- * 		interfaces can be used for redirection. The **BPF_F_INGRESS**
- * 		value in *flags* is used to make the distinction (ingress path
- * 		is selected if the flag is present, egress path otherwise).
- * 		This is the only flag supported for now.
- *
- * 		In comparison with **bpf_redirect**\ () helper,
- * 		**bpf_clone_redirect**\ () has the associated cost of
- * 		duplicating the packet buffer, but this can be executed out of
- * 		the eBPF program. Conversely, **bpf_redirect**\ () is more
- * 		efficient, but it is handled through an action code where the
- * 		redirection happens only after the eBPF program has returned.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * u64 bpf_get_current_pid_tgid(void)
- * 	Return
- * 		A 64-bit integer containing the current tgid and pid, and
- * 		created as such:
- * 		*current_task*\ **->tgid << 32 \|**
- * 		*current_task*\ **->pid**.
- *
- * u64 bpf_get_current_uid_gid(void)
- * 	Return
- * 		A 64-bit integer containing the current GID and UID, and
- * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
- *
- * int bpf_get_current_comm(char *buf, u32 size_of_buf)
- * 	Description
- * 		Copy the **comm** attribute of the current task into *buf* of
- * 		*size_of_buf*. The **comm** attribute contains the name of
- * 		the executable (excluding the path) for the current task. The
- * 		*size_of_buf* must be strictly positive. On success, the
- * 		helper makes sure that the *buf* is NUL-terminated. On failure,
- * 		it is filled with zeroes.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
- * 	Description
- * 		Retrieve the classid for the current task, i.e. for the net_cls
- * 		cgroup to which *skb* belongs.
- *
- * 		This helper can be used on TC egress path, but not on ingress.
- *
- * 		The net_cls cgroup provides an interface to tag network packets
- * 		based on a user-provided identifier for all traffic coming from
- * 		the tasks belonging to the related cgroup. See also the related
- * 		kernel documentation, available from the Linux sources in file
- * 		*Documentation/cgroup-v1/net_cls.txt*.
- *
- * 		The Linux kernel has two versions for cgroups: there are
- * 		cgroups v1 and cgroups v2. Both are available to users, who can
- * 		use a mixture of them, but note that the net_cls cgroup is for
- * 		cgroup v1 only. This makes it incompatible with BPF programs
- * 		run on cgroups, which is a cgroup-v2-only feature (a socket can
- * 		only hold data for one version of cgroups at a time).
- *
- * 		This helper is only available is the kernel was compiled with
- * 		the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
- * 		"**y**" or to "**m**".
- * 	Return
- * 		The classid, or 0 for the default unconfigured classid.
- *
- * int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
- * 	Description
- * 		Push a *vlan_tci* (VLAN tag control information) of protocol
- * 		*vlan_proto* to the packet associated to *skb*, then update
- * 		the checksum. Note that if *vlan_proto* is different from
- * 		**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
- * 		be **ETH_P_8021Q**.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_vlan_pop(struct sk_buff *skb)
- * 	Description
- * 		Pop a VLAN header from the packet associated to *skb*.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
- * 	Description
- * 		Get tunnel metadata. This helper takes a pointer *key* to an
- * 		empty **struct bpf_tunnel_key** of **size**, that will be
- * 		filled with tunnel metadata for the packet associated to *skb*.
- * 		The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
- * 		indicates that the tunnel is based on IPv6 protocol instead of
- * 		IPv4.
- *
- * 		The **struct bpf_tunnel_key** is an object that generalizes the
- * 		principal parameters used by various tunneling protocols into a
- * 		single struct. This way, it can be used to easily make a
- * 		decision based on the contents of the encapsulation header,
- * 		"summarized" in this struct. In particular, it holds the IP
- * 		address of the remote end (IPv4 or IPv6, depending on the case)
- * 		in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
- * 		this struct exposes the *key*\ **->tunnel_id**, which is
- * 		generally mapped to a VNI (Virtual Network Identifier), making
- * 		it programmable together with the **bpf_skb_set_tunnel_key**\
- * 		() helper.
- *
- * 		Let's imagine that the following code is part of a program
- * 		attached to the TC ingress interface, on one end of a GRE
- * 		tunnel, and is supposed to filter out all messages coming from
- * 		remote ends with IPv4 address other than 10.0.0.1:
- *
- * 		::
- *
- * 			int ret;
- * 			struct bpf_tunnel_key key = {};
- *
- * 			ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
- * 			if (ret < 0)
- * 				return TC_ACT_SHOT;	// drop packet
- *
- * 			if (key.remote_ipv4 != 0x0a000001)
- * 				return TC_ACT_SHOT;	// drop packet
- *
- * 			return TC_ACT_OK;		// accept packet
- *
- * 		This interface can also be used with all encapsulation devices
- * 		that can operate in "collect metadata" mode: instead of having
- * 		one network device per specific configuration, the "collect
- * 		metadata" mode only requires a single device where the
- * 		configuration can be extracted from this helper.
- *
- * 		This can be used together with various tunnels such as VXLan,
- * 		Geneve, GRE or IP in IP (IPIP).
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
- * 	Description
- * 		Populate tunnel metadata for packet associated to *skb.* The
- * 		tunnel metadata is set to the contents of *key*, of *size*. The
- * 		*flags* can be set to a combination of the following values:
- *
- * 		**BPF_F_TUNINFO_IPV6**
- * 			Indicate that the tunnel is based on IPv6 protocol
- * 			instead of IPv4.
- * 		**BPF_F_ZERO_CSUM_TX**
- * 			For IPv4 packets, add a flag to tunnel metadata
- * 			indicating that checksum computation should be skipped
- * 			and checksum set to zeroes.
- * 		**BPF_F_DONT_FRAGMENT**
- * 			Add a flag to tunnel metadata indicating that the
- * 			packet should not be fragmented.
- * 		**BPF_F_SEQ_NUMBER**
- * 			Add a flag to tunnel metadata indicating that a
- * 			sequence number should be added to tunnel header before
- * 			sending the packet. This flag was added for GRE
- * 			encapsulation, but might be used with other protocols
- * 			as well in the future.
- *
- * 		Here is a typical usage on the transmit path:
- *
- * 		::
- *
- * 			struct bpf_tunnel_key key;
- * 			     populate key ...
- * 			bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
- * 			bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
- *
- * 		See also the description of the **bpf_skb_get_tunnel_key**\ ()
- * 		helper for additional information.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
- * 	Description
- * 		Read the value of a perf event counter. This helper relies on a
- * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
- * 		the perf event counter is selected when *map* is updated with
- * 		perf event file descriptors. The *map* is an array whose size
- * 		is the number of available CPUs, and each cell contains a value
- * 		relative to one CPU. The value to retrieve is indicated by
- * 		*flags*, that contains the index of the CPU to look up, masked
- * 		with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
- * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
- * 		current CPU should be retrieved.
- *
- * 		Note that before Linux 4.13, only hardware perf event can be
- * 		retrieved.
- *
- * 		Also, be aware that the newer helper
- * 		**bpf_perf_event_read_value**\ () is recommended over
- * 		**bpf_perf_event_read**\ () in general. The latter has some ABI
- * 		quirks where error and counter value are used as a return code
- * 		(which is wrong to do since ranges may overlap). This issue is
- * 		fixed with **bpf_perf_event_read_value**\ (), which at the same
- * 		time provides more features over the **bpf_perf_event_read**\
- * 		() interface. Please refer to the description of
- * 		**bpf_perf_event_read_value**\ () for details.
- * 	Return
- * 		The value of the perf event counter read from the map, or a
- * 		negative error code in case of failure.
- *
- * int bpf_redirect(u32 ifindex, u64 flags)
- * 	Description
- * 		Redirect the packet to another net device of index *ifindex*.
- * 		This helper is somewhat similar to **bpf_clone_redirect**\
- * 		(), except that the packet is not cloned, which provides
- * 		increased performance.
- *
- * 		Except for XDP, both ingress and egress interfaces can be used
- * 		for redirection. The **BPF_F_INGRESS** value in *flags* is used
- * 		to make the distinction (ingress path is selected if the flag
- * 		is present, egress path otherwise). Currently, XDP only
- * 		supports redirection to the egress interface, and accepts no
- * 		flag at all.
- *
- * 		The same effect can be attained with the more generic
- * 		**bpf_redirect_map**\ (), which requires specific maps to be
- * 		used but offers better performance.
- * 	Return
- * 		For XDP, the helper returns **XDP_REDIRECT** on success or
- * 		**XDP_ABORTED** on error. For other program types, the values
- * 		are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
- * 		error.
- *
- * u32 bpf_get_route_realm(struct sk_buff *skb)
- * 	Description
- * 		Retrieve the realm or the route, that is to say the
- * 		**tclassid** field of the destination for the *skb*. The
- * 		indentifier retrieved is a user-provided tag, similar to the
- * 		one used with the net_cls cgroup (see description for
- * 		**bpf_get_cgroup_classid**\ () helper), but here this tag is
- * 		held by a route (a destination entry), not by a task.
- *
- * 		Retrieving this identifier works with the clsact TC egress hook
- * 		(see also **tc-bpf(8)**), or alternatively on conventional
- * 		classful egress qdiscs, but not on TC ingress path. In case of
- * 		clsact TC egress hook, this has the advantage that, internally,
- * 		the destination entry has not been dropped yet in the transmit
- * 		path. Therefore, the destination entry does not need to be
- * 		artificially held via **netif_keep_dst**\ () for a classful
- * 		qdisc until the *skb* is freed.
- *
- * 		This helper is available only if the kernel was compiled with
- * 		**CONFIG_IP_ROUTE_CLASSID** configuration option.
- * 	Return
- * 		The realm of the route for the packet associated to *skb*, or 0
- * 		if none was found.
- *
- * int bpf_perf_event_output(struct pt_reg *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
- * 	Description
- * 		Write raw *data* blob into a special BPF perf event held by
- * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
- * 		event must have the following attributes: **PERF_SAMPLE_RAW**
- * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
- * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
- *
- * 		The *flags* are used to indicate the index in *map* for which
- * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
- * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
- * 		to indicate that the index of the current CPU core should be
- * 		used.
- *
- * 		The value to write, of *size*, is passed through eBPF stack and
- * 		pointed by *data*.
- *
- * 		The context of the program *ctx* needs also be passed to the
- * 		helper.
- *
- * 		On user space, a program willing to read the values needs to
- * 		call **perf_event_open**\ () on the perf event (either for
- * 		one or for all CPUs) and to store the file descriptor into the
- * 		*map*. This must be done before the eBPF program can send data
- * 		into it. An example is available in file
- * 		*samples/bpf/trace_output_user.c* in the Linux kernel source
- * 		tree (the eBPF program counterpart is in
- * 		*samples/bpf/trace_output_kern.c*).
- *
- * 		**bpf_perf_event_output**\ () achieves better performance
- * 		than **bpf_trace_printk**\ () for sharing data with user
- * 		space, and is much better suitable for streaming data from eBPF
- * 		programs.
- *
- * 		Note that this helper is not restricted to tracing use cases
- * 		and can be used with programs attached to TC or XDP as well,
- * 		where it allows for passing data to user space listeners. Data
- * 		can be:
- *
- * 		* Only custom structs,
- * 		* Only the packet payload, or
- * 		* A combination of both.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
- * 	Description
- * 		This helper was provided as an easy way to load data from a
- * 		packet. It can be used to load *len* bytes from *offset* from
- * 		the packet associated to *skb*, into the buffer pointed by
- * 		*to*.
- *
- * 		Since Linux 4.7, usage of this helper has mostly been replaced
- * 		by "direct packet access", enabling packet data to be
- * 		manipulated with *skb*\ **->data** and *skb*\ **->data_end**
- * 		pointing respectively to the first byte of packet data and to
- * 		the byte after the last byte of packet data. However, it
- * 		remains useful if one wishes to read large quantities of data
- * 		at once from a packet into the eBPF stack.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_get_stackid(struct pt_reg *ctx, struct bpf_map *map, u64 flags)
- * 	Description
- * 		Walk a user or a kernel stack and return its id. To achieve
- * 		this, the helper needs *ctx*, which is a pointer to the context
- * 		on which the tracing program is executed, and a pointer to a
- * 		*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
- *
- * 		The last argument, *flags*, holds the number of stack frames to
- * 		skip (from 0 to 255), masked with
- * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
- * 		a combination of the following flags:
- *
- * 		**BPF_F_USER_STACK**
- * 			Collect a user space stack instead of a kernel stack.
- * 		**BPF_F_FAST_STACK_CMP**
- * 			Compare stacks by hash only.
- * 		**BPF_F_REUSE_STACKID**
- * 			If two different stacks hash into the same *stackid*,
- * 			discard the old one.
- *
- * 		The stack id retrieved is a 32 bit long integer handle which
- * 		can be further combined with other data (including other stack
- * 		ids) and used as a key into maps. This can be useful for
- * 		generating a variety of graphs (such as flame graphs or off-cpu
- * 		graphs).
- *
- * 		For walking a stack, this helper is an improvement over
- * 		**bpf_probe_read**\ (), which can be used with unrolled loops
- * 		but is not efficient and consumes a lot of eBPF instructions.
- * 		Instead, **bpf_get_stackid**\ () can collect up to
- * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
- * 		this limit can be controlled with the **sysctl** program, and
- * 		that it should be manually increased in order to profile long
- * 		user stacks (such as stacks for Java programs). To do so, use:
- *
- * 		::
- *
- * 			# sysctl kernel.perf_event_max_stack=<new value>
- * 	Return
- * 		The positive or null stack id on success, or a negative error
- * 		in case of failure.
- *
- * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
- * 	Description
- * 		Compute a checksum difference, from the raw buffer pointed by
- * 		*from*, of length *from_size* (that must be a multiple of 4),
- * 		towards the raw buffer pointed by *to*, of size *to_size*
- * 		(same remark). An optional *seed* can be added to the value
- * 		(this can be cascaded, the seed may come from a previous call
- * 		to the helper).
- *
- * 		This is flexible enough to be used in several ways:
- *
- * 		* With *from_size* == 0, *to_size* > 0 and *seed* set to
- * 		  checksum, it can be used when pushing new data.
- * 		* With *from_size* > 0, *to_size* == 0 and *seed* set to
- * 		  checksum, it can be used when removing data from a packet.
- * 		* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
- * 		  can be used to compute a diff. Note that *from_size* and
- * 		  *to_size* do not need to be equal.
- *
- * 		This helper can be used in combination with
- * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
- * 		which one can feed in the difference computed with
- * 		**bpf_csum_diff**\ ().
- * 	Return
- * 		The checksum result, or a negative error code in case of
- * 		failure.
- *
- * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
- * 	Description
- * 		Retrieve tunnel options metadata for the packet associated to
- * 		*skb*, and store the raw tunnel option data to the buffer *opt*
- * 		of *size*.
- *
- * 		This helper can be used with encapsulation devices that can
- * 		operate in "collect metadata" mode (please refer to the related
- * 		note in the description of **bpf_skb_get_tunnel_key**\ () for
- * 		more details). A particular example where this can be used is
- * 		in combination with the Geneve encapsulation protocol, where it
- * 		allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
- * 		and retrieving arbitrary TLVs (Type-Length-Value headers) from
- * 		the eBPF program. This allows for full customization of these
- * 		headers.
- * 	Return
- * 		The size of the option data retrieved.
- *
- * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
- * 	Description
- * 		Set tunnel options metadata for the packet associated to *skb*
- * 		to the option data contained in the raw buffer *opt* of *size*.
- *
- * 		See also the description of the **bpf_skb_get_tunnel_opt**\ ()
- * 		helper for additional information.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
- * 	Description
- * 		Change the protocol of the *skb* to *proto*. Currently
- * 		supported are transition from IPv4 to IPv6, and from IPv6 to
- * 		IPv4. The helper takes care of the groundwork for the
- * 		transition, including resizing the socket buffer. The eBPF
- * 		program is expected to fill the new headers, if any, via
- * 		**skb_store_bytes**\ () and to recompute the checksums with
- * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
- * 		(). The main case for this helper is to perform NAT64
- * 		operations out of an eBPF program.
- *
- * 		Internally, the GSO type is marked as dodgy so that headers are
- * 		checked and segments are recalculated by the GSO/GRO engine.
- * 		The size for GSO target is adapted as well.
- *
- * 		All values for *flags* are reserved for future usage, and must
- * 		be left at zero.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_change_type(struct sk_buff *skb, u32 type)
- * 	Description
- * 		Change the packet type for the packet associated to *skb*. This
- * 		comes down to setting *skb*\ **->pkt_type** to *type*, except
- * 		the eBPF program does not have a write access to *skb*\
- * 		**->pkt_type** beside this helper. Using a helper here allows
- * 		for graceful handling of errors.
- *
- * 		The major use case is to change incoming *skb*s to
- * 		**PACKET_HOST** in a programmatic way instead of having to
- * 		recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
- * 		example.
- *
- * 		Note that *type* only allows certain values. At this time, they
- * 		are:
- *
- * 		**PACKET_HOST**
- * 			Packet is for us.
- * 		**PACKET_BROADCAST**
- * 			Send packet to all.
- * 		**PACKET_MULTICAST**
- * 			Send packet to group.
- * 		**PACKET_OTHERHOST**
- * 			Send packet to someone else.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
- * 	Description
- * 		Check whether *skb* is a descendant of the cgroup2 held by
- * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
- * 	Return
- * 		The return value depends on the result of the test, and can be:
- *
- * 		* 0, if the *skb* failed the cgroup2 descendant test.
- * 		* 1, if the *skb* succeeded the cgroup2 descendant test.
- * 		* A negative error code, if an error occurred.
- *
- * u32 bpf_get_hash_recalc(struct sk_buff *skb)
- * 	Description
- * 		Retrieve the hash of the packet, *skb*\ **->hash**. If it is
- * 		not set, in particular if the hash was cleared due to mangling,
- * 		recompute this hash. Later accesses to the hash can be done
- * 		directly with *skb*\ **->hash**.
- *
- * 		Calling **bpf_set_hash_invalid**\ (), changing a packet
- * 		prototype with **bpf_skb_change_proto**\ (), or calling
- * 		**bpf_skb_store_bytes**\ () with the
- * 		**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
- * 		the hash and to trigger a new computation for the next call to
- * 		**bpf_get_hash_recalc**\ ().
- * 	Return
- * 		The 32-bit hash.
- *
- * u64 bpf_get_current_task(void)
- * 	Return
- * 		A pointer to the current task struct.
- *
- * int bpf_probe_write_user(void *dst, const void *src, u32 len)
- * 	Description
- * 		Attempt in a safe way to write *len* bytes from the buffer
- * 		*src* to *dst* in memory. It only works for threads that are in
- * 		user context, and *dst* must be a valid user space address.
- *
- * 		This helper should not be used to implement any kind of
- * 		security mechanism because of TOC-TOU attacks, but rather to
- * 		debug, divert, and manipulate execution of semi-cooperative
- * 		processes.
- *
- * 		Keep in mind that this feature is meant for experiments, and it
- * 		has a risk of crashing the system and running programs.
- * 		Therefore, when an eBPF program using this helper is attached,
- * 		a warning including PID and process name is printed to kernel
- * 		logs.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
- * 	Description
- * 		Check whether the probe is being run is the context of a given
- * 		subset of the cgroup2 hierarchy. The cgroup2 to test is held by
- * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
- * 	Return
- * 		The return value depends on the result of the test, and can be:
- *
- * 		* 0, if the *skb* task belongs to the cgroup2.
- * 		* 1, if the *skb* task does not belong to the cgroup2.
- * 		* A negative error code, if an error occurred.
- *
- * int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
- * 	Description
- * 		Resize (trim or grow) the packet associated to *skb* to the
- * 		new *len*. The *flags* are reserved for future usage, and must
- * 		be left at zero.
- *
- * 		The basic idea is that the helper performs the needed work to
- * 		change the size of the packet, then the eBPF program rewrites
- * 		the rest via helpers like **bpf_skb_store_bytes**\ (),
- * 		**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
- * 		and others. This helper is a slow path utility intended for
- * 		replies with control messages. And because it is targeted for
- * 		slow path, the helper itself can afford to be slow: it
- * 		implicitly linearizes, unclones and drops offloads from the
- * 		*skb*.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
- * 	Description
- * 		Pull in non-linear data in case the *skb* is non-linear and not
- * 		all of *len* are part of the linear section. Make *len* bytes
- * 		from *skb* readable and writable. If a zero value is passed for
- * 		*len*, then the whole length of the *skb* is pulled.
- *
- * 		This helper is only needed for reading and writing with direct
- * 		packet access.
- *
- * 		For direct packet access, testing that offsets to access
- * 		are within packet boundaries (test on *skb*\ **->data_end**) is
- * 		susceptible to fail if offsets are invalid, or if the requested
- * 		data is in non-linear parts of the *skb*. On failure the
- * 		program can just bail out, or in the case of a non-linear
- * 		buffer, use a helper to make the data available. The
- * 		**bpf_skb_load_bytes**\ () helper is a first solution to access
- * 		the data. Another one consists in using **bpf_skb_pull_data**
- * 		to pull in once the non-linear parts, then retesting and
- * 		eventually access the data.
- *
- * 		At the same time, this also makes sure the *skb* is uncloned,
- * 		which is a necessary condition for direct write. As this needs
- * 		to be an invariant for the write part only, the verifier
- * 		detects writes and adds a prologue that is calling
- * 		**bpf_skb_pull_data()** to effectively unclone the *skb* from
- * 		the very beginning in case it is indeed cloned.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
- * 	Description
- * 		Add the checksum *csum* into *skb*\ **->csum** in case the
- * 		driver has supplied a checksum for the entire packet into that
- * 		field. Return an error otherwise. This helper is intended to be
- * 		used in combination with **bpf_csum_diff**\ (), in particular
- * 		when the checksum needs to be updated after data has been
- * 		written into the packet through direct packet access.
- * 	Return
- * 		The checksum on success, or a negative error code in case of
- * 		failure.
- *
- * void bpf_set_hash_invalid(struct sk_buff *skb)
- * 	Description
- * 		Invalidate the current *skb*\ **->hash**. It can be used after
- * 		mangling on headers through direct packet access, in order to
- * 		indicate that the hash is outdated and to trigger a
- * 		recalculation the next time the kernel tries to access this
- * 		hash or when the **bpf_get_hash_recalc**\ () helper is called.
- *
- * int bpf_get_numa_node_id(void)
- * 	Description
- * 		Return the id of the current NUMA node. The primary use case
- * 		for this helper is the selection of sockets for the local NUMA
- * 		node, when the program is attached to sockets using the
- * 		**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
- * 		but the helper is also available to other eBPF program types,
- * 		similarly to **bpf_get_smp_processor_id**\ ().
- * 	Return
- * 		The id of current NUMA node.
- *
- * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
- * 	Description
- * 		Grows headroom of packet associated to *skb* and adjusts the
- * 		offset of the MAC header accordingly, adding *len* bytes of
- * 		space. It automatically extends and reallocates memory as
- * 		required.
- *
- * 		This helper can be used on a layer 3 *skb* to push a MAC header
- * 		for redirection into a layer 2 device.
- *
- * 		All values for *flags* are reserved for future usage, and must
- * 		be left at zero.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
- * 	Description
- * 		Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
- * 		it is possible to use a negative value for *delta*. This helper
- * 		can be used to prepare the packet for pushing or popping
- * 		headers.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
- * 	Description
- * 		Copy a NUL terminated string from an unsafe address
- * 		*unsafe_ptr* to *dst*. The *size* should include the
- * 		terminating NUL byte. In case the string length is smaller than
- * 		*size*, the target is not padded with further NUL bytes. If the
- * 		string length is larger than *size*, just *size*-1 bytes are
- * 		copied and the last byte is set to NUL.
- *
- * 		On success, the length of the copied string is returned. This
- * 		makes this helper useful in tracing programs for reading
- * 		strings, and more importantly to get its length at runtime. See
- * 		the following snippet:
- *
- * 		::
- *
- * 			SEC("kprobe/sys_open")
- * 			void bpf_sys_open(struct pt_regs *ctx)
- * 			{
- * 			        char buf[PATHLEN]; // PATHLEN is defined to 256
- * 			        int res = bpf_probe_read_str(buf, sizeof(buf),
- * 				                             ctx->di);
- *
- * 				// Consume buf, for example push it to
- * 				// userspace via bpf_perf_event_output(); we
- * 				// can use res (the string length) as event
- * 				// size, after checking its boundaries.
- * 			}
- *
- * 		In comparison, using **bpf_probe_read()** helper here instead
- * 		to read the string would require to estimate the length at
- * 		compile time, and would often result in copying more memory
- * 		than necessary.
- *
- * 		Another useful use case is when parsing individual process
- * 		arguments or individual environment variables navigating
- * 		*current*\ **->mm->arg_start** and *current*\
- * 		**->mm->env_start**: using this helper and the return value,
- * 		one can quickly iterate at the right offset of the memory area.
- * 	Return
- * 		On success, the strictly positive length of the string,
- * 		including the trailing NUL character. On error, a negative
- * 		value.
- *
- * u64 bpf_get_socket_cookie(struct sk_buff *skb)
- * 	Description
- * 		If the **struct sk_buff** pointed by *skb* has a known socket,
- * 		retrieve the cookie (generated by the kernel) of this socket.
- * 		If no cookie has been set yet, generate a new cookie. Once
- * 		generated, the socket cookie remains stable for the life of the
- * 		socket. This helper can be useful for monitoring per socket
- * 		networking traffic statistics as it provides a unique socket
- * 		identifier per namespace.
- * 	Return
- * 		A 8-byte long non-decreasing number on success, or 0 if the
- * 		socket field is missing inside *skb*.
- *
- * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
- * 	Description
- * 		Equivalent to bpf_get_socket_cookie() helper that accepts
- * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
- * 	Return
- * 		A 8-byte long non-decreasing number.
- *
- * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
- * 	Description
- * 		Equivalent to bpf_get_socket_cookie() helper that accepts
- * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
- * 	Return
- * 		A 8-byte long non-decreasing number.
- *
- * u32 bpf_get_socket_uid(struct sk_buff *skb)
- * 	Return
- * 		The owner UID of the socket associated to *skb*. If the socket
- * 		is **NULL**, or if it is not a full socket (i.e. if it is a
- * 		time-wait or a request socket instead), **overflowuid** value
- * 		is returned (note that **overflowuid** might also be the actual
- * 		UID value for the socket).
- *
- * u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
- * 	Description
- * 		Set the full hash for *skb* (set the field *skb*\ **->hash**)
- * 		to value *hash*.
- * 	Return
- * 		0
- *
- * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
- * 	Description
- * 		Emulate a call to **setsockopt()** on the socket associated to
- * 		*bpf_socket*, which must be a full socket. The *level* at
- * 		which the option resides and the name *optname* of the option
- * 		must be specified, see **setsockopt(2)** for more information.
- * 		The option value of length *optlen* is pointed by *optval*.
- *
- * 		This helper actually implements a subset of **setsockopt()**.
- * 		It supports the following *level*\ s:
- *
- * 		* **SOL_SOCKET**, which supports the following *optname*\ s:
- * 		  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
- * 		  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
- * 		* **IPPROTO_TCP**, which supports the following *optname*\ s:
- * 		  **TCP_CONGESTION**, **TCP_BPF_IW**,
- * 		  **TCP_BPF_SNDCWND_CLAMP**.
- * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
- * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
- * 	Description
- * 		Grow or shrink the room for data in the packet associated to
- * 		*skb* by *len_diff*, and according to the selected *mode*.
- *
- *		There are two supported modes at this time:
- *
- *		* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
- *		  (room space is added or removed below the layer 2 header).
- *
- * 		* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
- * 		  (room space is added or removed below the layer 3 header).
- *
- *		The following flags are supported at this time:
- *
- *		* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
- *		  Adjusting mss in this way is not allowed for datagrams.
- *
- *		* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 **:
- *		* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 **:
- *		  Any new space is reserved to hold a tunnel header.
- *		  Configure skb offsets and other fields accordingly.
- *
- *		* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE **:
- *		* **BPF_F_ADJ_ROOM_ENCAP_L4_UDP **:
- *		  Use with ENCAP_L3 flags to further specify the tunnel type.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
- * 	Description
- * 		Redirect the packet to the endpoint referenced by *map* at
- * 		index *key*. Depending on its type, this *map* can contain
- * 		references to net devices (for forwarding packets through other
- * 		ports), or to CPUs (for redirecting XDP frames to another CPU;
- * 		but this is only implemented for native XDP (with driver
- * 		support) as of this writing).
- *
- * 		All values for *flags* are reserved for future usage, and must
- * 		be left at zero.
- *
- * 		When used to redirect packets to net devices, this helper
- * 		provides a high performance increase over **bpf_redirect**\ ().
- * 		This is due to various implementation details of the underlying
- * 		mechanisms, one of which is the fact that **bpf_redirect_map**\
- * 		() tries to send packet as a "bulk" to the device.
- * 	Return
- * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
- *
- * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
- * 	Description
- * 		Redirect the packet to the socket referenced by *map* (of type
- * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
- * 		egress interfaces can be used for redirection. The
- * 		**BPF_F_INGRESS** value in *flags* is used to make the
- * 		distinction (ingress path is selected if the flag is present,
- * 		egress path otherwise). This is the only flag supported for now.
- * 	Return
- * 		**SK_PASS** on success, or **SK_DROP** on error.
- *
- * int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
- * 	Description
- * 		Add an entry to, or update a *map* referencing sockets. The
- * 		*skops* is used as a new value for the entry associated to
- * 		*key*. *flags* is one of:
- *
- * 		**BPF_NOEXIST**
- * 			The entry for *key* must not exist in the map.
- * 		**BPF_EXIST**
- * 			The entry for *key* must already exist in the map.
- * 		**BPF_ANY**
- * 			No condition on the existence of the entry for *key*.
- *
- * 		If the *map* has eBPF programs (parser and verdict), those will
- * 		be inherited by the socket being added. If the socket is
- * 		already attached to eBPF programs, this results in an error.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
- * 	Description
- * 		Adjust the address pointed by *xdp_md*\ **->data_meta** by
- * 		*delta* (which can be positive or negative). Note that this
- * 		operation modifies the address stored in *xdp_md*\ **->data**,
- * 		so the latter must be loaded only after the helper has been
- * 		called.
- *
- * 		The use of *xdp_md*\ **->data_meta** is optional and programs
- * 		are not required to use it. The rationale is that when the
- * 		packet is processed with XDP (e.g. as DoS filter), it is
- * 		possible to push further meta data along with it before passing
- * 		to the stack, and to give the guarantee that an ingress eBPF
- * 		program attached as a TC classifier on the same device can pick
- * 		this up for further post-processing. Since TC works with socket
- * 		buffers, it remains possible to set from XDP the **mark** or
- * 		**priority** pointers, or other pointers for the socket buffer.
- * 		Having this scratch space generic and programmable allows for
- * 		more flexibility as the user is free to store whatever meta
- * 		data they need.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
- * 	Description
- * 		Read the value of a perf event counter, and store it into *buf*
- * 		of size *buf_size*. This helper relies on a *map* of type
- * 		**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
- * 		counter is selected when *map* is updated with perf event file
- * 		descriptors. The *map* is an array whose size is the number of
- * 		available CPUs, and each cell contains a value relative to one
- * 		CPU. The value to retrieve is indicated by *flags*, that
- * 		contains the index of the CPU to look up, masked with
- * 		**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
- * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
- * 		current CPU should be retrieved.
- *
- * 		This helper behaves in a way close to
- * 		**bpf_perf_event_read**\ () helper, save that instead of
- * 		just returning the value observed, it fills the *buf*
- * 		structure. This allows for additional data to be retrieved: in
- * 		particular, the enabled and running times (in *buf*\
- * 		**->enabled** and *buf*\ **->running**, respectively) are
- * 		copied. In general, **bpf_perf_event_read_value**\ () is
- * 		recommended over **bpf_perf_event_read**\ (), which has some
- * 		ABI issues and provides fewer functionalities.
- *
- * 		These values are interesting, because hardware PMU (Performance
- * 		Monitoring Unit) counters are limited resources. When there are
- * 		more PMU based perf events opened than available counters,
- * 		kernel will multiplex these events so each event gets certain
- * 		percentage (but not all) of the PMU time. In case that
- * 		multiplexing happens, the number of samples or counter value
- * 		will not reflect the case compared to when no multiplexing
- * 		occurs. This makes comparison between different runs difficult.
- * 		Typically, the counter value should be normalized before
- * 		comparing to other experiments. The usual normalization is done
- * 		as follows.
- *
- * 		::
- *
- * 			normalized_counter = counter * t_enabled / t_running
- *
- * 		Where t_enabled is the time enabled for event and t_running is
- * 		the time running for event since last normalization. The
- * 		enabled and running times are accumulated since the perf event
- * 		open. To achieve scaling factor between two invocations of an
- * 		eBPF program, users can can use CPU id as the key (which is
- * 		typical for perf array usage model) to remember the previous
- * 		value and do the calculation inside the eBPF program.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
- * 	Description
- * 		For en eBPF program attached to a perf event, retrieve the
- * 		value of the event counter associated to *ctx* and store it in
- * 		the structure pointed by *buf* and of size *buf_size*. Enabled
- * 		and running times are also stored in the structure (see
- * 		description of helper **bpf_perf_event_read_value**\ () for
- * 		more details).
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
- * 	Description
- * 		Emulate a call to **getsockopt()** on the socket associated to
- * 		*bpf_socket*, which must be a full socket. The *level* at
- * 		which the option resides and the name *optname* of the option
- * 		must be specified, see **getsockopt(2)** for more information.
- * 		The retrieved value is stored in the structure pointed by
- * 		*opval* and of length *optlen*.
- *
- * 		This helper actually implements a subset of **getsockopt()**.
- * 		It supports the following *level*\ s:
- *
- * 		* **IPPROTO_TCP**, which supports *optname*
- * 		  **TCP_CONGESTION**.
- * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
- * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_override_return(struct pt_reg *regs, u64 rc)
- * 	Description
- * 		Used for error injection, this helper uses kprobes to override
- * 		the return value of the probed function, and to set it to *rc*.
- * 		The first argument is the context *regs* on which the kprobe
- * 		works.
- *
- * 		This helper works by setting setting the PC (program counter)
- * 		to an override function which is run in place of the original
- * 		probed function. This means the probed function is not run at
- * 		all. The replacement function just returns with the required
- * 		value.
- *
- * 		This helper has security implications, and thus is subject to
- * 		restrictions. It is only available if the kernel was compiled
- * 		with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
- * 		option, and in this case it only works on functions tagged with
- * 		**ALLOW_ERROR_INJECTION** in the kernel code.
- *
- * 		Also, the helper is only available for the architectures having
- * 		the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
- * 		x86 architecture is the only one to support this feature.
- * 	Return
- * 		0
- *
- * int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
- * 	Description
- * 		Attempt to set the value of the **bpf_sock_ops_cb_flags** field
- * 		for the full TCP socket associated to *bpf_sock_ops* to
- * 		*argval*.
- *
- * 		The primary use of this field is to determine if there should
- * 		be calls to eBPF programs of type
- * 		**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
- * 		code. A program of the same type can change its value, per
- * 		connection and as necessary, when the connection is
- * 		established. This field is directly accessible for reading, but
- * 		this helper must be used for updates in order to return an
- * 		error if an eBPF program tries to set a callback that is not
- * 		supported in the current kernel.
- *
- * 		The supported callback values that *argval* can combine are:
- *
- * 		* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
- * 		* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
- * 		* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
- *
- * 		Here are some examples of where one could call such eBPF
- * 		program:
- *
- * 		* When RTO fires.
- * 		* When a packet is retransmitted.
- * 		* When the connection terminates.
- * 		* When a packet is sent.
- * 		* When a packet is received.
- * 	Return
- * 		Code **-EINVAL** if the socket is not a full TCP socket;
- * 		otherwise, a positive number containing the bits that could not
- * 		be set is returned (which comes down to 0 if all bits were set
- * 		as required).
- *
- * int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
- * 	Description
- * 		This helper is used in programs implementing policies at the
- * 		socket level. If the message *msg* is allowed to pass (i.e. if
- * 		the verdict eBPF program returns **SK_PASS**), redirect it to
- * 		the socket referenced by *map* (of type
- * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
- * 		egress interfaces can be used for redirection. The
- * 		**BPF_F_INGRESS** value in *flags* is used to make the
- * 		distinction (ingress path is selected if the flag is present,
- * 		egress path otherwise). This is the only flag supported for now.
- * 	Return
- * 		**SK_PASS** on success, or **SK_DROP** on error.
- *
- * int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
- * 	Description
- * 		For socket policies, apply the verdict of the eBPF program to
- * 		the next *bytes* (number of bytes) of message *msg*.
- *
- * 		For example, this helper can be used in the following cases:
- *
- * 		* A single **sendmsg**\ () or **sendfile**\ () system call
- * 		  contains multiple logical messages that the eBPF program is
- * 		  supposed to read and for which it should apply a verdict.
- * 		* An eBPF program only cares to read the first *bytes* of a
- * 		  *msg*. If the message has a large payload, then setting up
- * 		  and calling the eBPF program repeatedly for all bytes, even
- * 		  though the verdict is already known, would create unnecessary
- * 		  overhead.
- *
- * 		When called from within an eBPF program, the helper sets a
- * 		counter internal to the BPF infrastructure, that is used to
- * 		apply the last verdict to the next *bytes*. If *bytes* is
- * 		smaller than the current data being processed from a
- * 		**sendmsg**\ () or **sendfile**\ () system call, the first
- * 		*bytes* will be sent and the eBPF program will be re-run with
- * 		the pointer for start of data pointing to byte number *bytes*
- * 		**+ 1**. If *bytes* is larger than the current data being
- * 		processed, then the eBPF verdict will be applied to multiple
- * 		**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
- * 		consumed.
- *
- * 		Note that if a socket closes with the internal counter holding
- * 		a non-zero value, this is not a problem because data is not
- * 		being buffered for *bytes* and is sent as it is received.
- * 	Return
- * 		0
- *
- * int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
- * 	Description
- * 		For socket policies, prevent the execution of the verdict eBPF
- * 		program for message *msg* until *bytes* (byte number) have been
- * 		accumulated.
- *
- * 		This can be used when one needs a specific number of bytes
- * 		before a verdict can be assigned, even if the data spans
- * 		multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
- * 		case would be a user calling **sendmsg**\ () repeatedly with
- * 		1-byte long message segments. Obviously, this is bad for
- * 		performance, but it is still valid. If the eBPF program needs
- * 		*bytes* bytes to validate a header, this helper can be used to
- * 		prevent the eBPF program to be called again until *bytes* have
- * 		been accumulated.
- * 	Return
- * 		0
- *
- * int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
- * 	Description
- * 		For socket policies, pull in non-linear data from user space
- * 		for *msg* and set pointers *msg*\ **->data** and *msg*\
- * 		**->data_end** to *start* and *end* bytes offsets into *msg*,
- * 		respectively.
- *
- * 		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
- * 		*msg* it can only parse data that the (**data**, **data_end**)
- * 		pointers have already consumed. For **sendmsg**\ () hooks this
- * 		is likely the first scatterlist element. But for calls relying
- * 		on the **sendpage** handler (e.g. **sendfile**\ ()) this will
- * 		be the range (**0**, **0**) because the data is shared with
- * 		user space and by default the objective is to avoid allowing
- * 		user space to modify data while (or after) eBPF verdict is
- * 		being decided. This helper can be used to pull in data and to
- * 		set the start and end pointer to given values. Data will be
- * 		copied if necessary (i.e. if data was not linear and if start
- * 		and end pointers do not point to the same chunk).
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- *
- * 		All values for *flags* are reserved for future usage, and must
- * 		be left at zero.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
- * 	Description
- * 		Bind the socket associated to *ctx* to the address pointed by
- * 		*addr*, of length *addr_len*. This allows for making outgoing
- * 		connection from the desired IP address, which can be useful for
- * 		example when all processes inside a cgroup should use one
- * 		single IP address on a host that has multiple IP configured.
- *
- * 		This helper works for IPv4 and IPv6, TCP and UDP sockets. The
- * 		domain (*addr*\ **->sa_family**) must be **AF_INET** (or
- * 		**AF_INET6**). Looking for a free port to bind to can be
- * 		expensive, therefore binding to port is not permitted by the
- * 		helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
- * 		must be set to zero.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
- * 	Description
- * 		Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
- * 		only possible to shrink the packet as of this writing,
- * 		therefore *delta* must be a negative integer.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
- * 	Description
- * 		Retrieve the XFRM state (IP transform framework, see also
- * 		**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
- *
- * 		The retrieved value is stored in the **struct bpf_xfrm_state**
- * 		pointed by *xfrm_state* and of length *size*.
- *
- * 		All values for *flags* are reserved for future usage, and must
- * 		be left at zero.
- *
- * 		This helper is available only if the kernel was compiled with
- * 		**CONFIG_XFRM** configuration option.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
- * 	Description
- * 		Return a user or a kernel stack in bpf program provided buffer.
- * 		To achieve this, the helper needs *ctx*, which is a pointer
- * 		to the context on which the tracing program is executed.
- * 		To store the stacktrace, the bpf program provides *buf* with
- * 		a nonnegative *size*.
- *
- * 		The last argument, *flags*, holds the number of stack frames to
- * 		skip (from 0 to 255), masked with
- * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
- * 		the following flags:
- *
- * 		**BPF_F_USER_STACK**
- * 			Collect a user space stack instead of a kernel stack.
- * 		**BPF_F_USER_BUILD_ID**
- * 			Collect buildid+offset instead of ips for user stack,
- * 			only valid if **BPF_F_USER_STACK** is also specified.
- *
- * 		**bpf_get_stack**\ () can collect up to
- * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
- * 		to sufficient large buffer size. Note that
- * 		this limit can be controlled with the **sysctl** program, and
- * 		that it should be manually increased in order to profile long
- * 		user stacks (such as stacks for Java programs). To do so, use:
- *
- * 		::
- *
- * 			# sysctl kernel.perf_event_max_stack=<new value>
- * 	Return
- * 		A non-negative value equal to or less than *size* on success,
- * 		or a negative error in case of failure.
- *
- * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
- * 	Description
- * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
- * 		it provides an easy way to load *len* bytes from *offset*
- * 		from the packet associated to *skb*, into the buffer pointed
- * 		by *to*. The difference to **bpf_skb_load_bytes**\ () is that
- * 		a fifth argument *start_header* exists in order to select a
- * 		base offset to start from. *start_header* can be one of:
- *
- * 		**BPF_HDR_START_MAC**
- * 			Base offset to load data from is *skb*'s mac header.
- * 		**BPF_HDR_START_NET**
- * 			Base offset to load data from is *skb*'s network header.
- *
- * 		In general, "direct packet access" is the preferred method to
- * 		access packet data, however, this helper is in particular useful
- * 		in socket filters where *skb*\ **->data** does not always point
- * 		to the start of the mac header and where "direct packet access"
- * 		is not available.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
- *	Description
- *		Do FIB lookup in kernel tables using parameters in *params*.
- *		If lookup is successful and result shows packet is to be
- *		forwarded, the neighbor tables are searched for the nexthop.
- *		If successful (ie., FIB lookup shows forwarding and nexthop
- *		is resolved), the nexthop address is returned in ipv4_dst
- *		or ipv6_dst based on family, smac is set to mac address of
- *		egress device, dmac is set to nexthop mac address, rt_metric
- *		is set to metric from route (IPv4/IPv6 only), and ifindex
- *		is set to the device index of the nexthop from the FIB lookup.
- *
- *		*plen* argument is the size of the passed in struct.
- *		*flags* argument can be a combination of one or more of the
- *		following values:
- *
- *		**BPF_FIB_LOOKUP_DIRECT**
- *			Do a direct table lookup vs full lookup using FIB
- *			rules.
- *		**BPF_FIB_LOOKUP_OUTPUT**
- *			Perform lookup from an egress perspective (default is
- *			ingress).
- *
- *		*ctx* is either **struct xdp_md** for XDP programs or
- *		**struct sk_buff** tc cls_act programs.
- *	Return
- *		* < 0 if any input argument is invalid
- *		*   0 on success (packet is forwarded, nexthop neighbor exists)
- *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
- *		  packet is not forwarded or needs assist from full stack
- *
- * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
- *	Description
- *		Add an entry to, or update a sockhash *map* referencing sockets.
- *		The *skops* is used as a new value for the entry associated to
- *		*key*. *flags* is one of:
- *
- *		**BPF_NOEXIST**
- *			The entry for *key* must not exist in the map.
- *		**BPF_EXIST**
- *			The entry for *key* must already exist in the map.
- *		**BPF_ANY**
- *			No condition on the existence of the entry for *key*.
- *
- *		If the *map* has eBPF programs (parser and verdict), those will
- *		be inherited by the socket being added. If the socket is
- *		already attached to eBPF programs, this results in an error.
- *	Return
- *		0 on success, or a negative error in case of failure.
- *
- * int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
- *	Description
- *		This helper is used in programs implementing policies at the
- *		socket level. If the message *msg* is allowed to pass (i.e. if
- *		the verdict eBPF program returns **SK_PASS**), redirect it to
- *		the socket referenced by *map* (of type
- *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
- *		egress interfaces can be used for redirection. The
- *		**BPF_F_INGRESS** value in *flags* is used to make the
- *		distinction (ingress path is selected if the flag is present,
- *		egress path otherwise). This is the only flag supported for now.
- *	Return
- *		**SK_PASS** on success, or **SK_DROP** on error.
- *
- * int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
- *	Description
- *		This helper is used in programs implementing policies at the
- *		skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
- *		if the verdeict eBPF program returns **SK_PASS**), redirect it
- *		to the socket referenced by *map* (of type
- *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
- *		egress interfaces can be used for redirection. The
- *		**BPF_F_INGRESS** value in *flags* is used to make the
- *		distinction (ingress path is selected if the flag is present,
- *		egress otherwise). This is the only flag supported for now.
- *	Return
- *		**SK_PASS** on success, or **SK_DROP** on error.
- *
- * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
- *	Description
- *		Encapsulate the packet associated to *skb* within a Layer 3
- *		protocol header. This header is provided in the buffer at
- *		address *hdr*, with *len* its size in bytes. *type* indicates
- *		the protocol of the header and can be one of:
- *
- *		**BPF_LWT_ENCAP_SEG6**
- *			IPv6 encapsulation with Segment Routing Header
- *			(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
- *			the IPv6 header is computed by the kernel.
- *		**BPF_LWT_ENCAP_SEG6_INLINE**
- *			Only works if *skb* contains an IPv6 packet. Insert a
- *			Segment Routing Header (**struct ipv6_sr_hdr**) inside
- *			the IPv6 header.
- *		**BPF_LWT_ENCAP_IP**
- *			IP encapsulation (GRE/GUE/IPIP/etc). The outer header
- *			must be IPv4 or IPv6, followed by zero or more
- *			additional headers, up to LWT_BPF_MAX_HEADROOM total
- *			bytes in all prepended headers. Please note that
- *			if skb_is_gso(skb) is true, no more than two headers
- *			can be prepended, and the inner header, if present,
- *			should be either GRE or UDP/GUE.
- *
- *		BPF_LWT_ENCAP_SEG6*** types can be called by bpf programs of
- *		type BPF_PROG_TYPE_LWT_IN; BPF_LWT_ENCAP_IP type can be called
- *		by bpf programs of types BPF_PROG_TYPE_LWT_IN and
- *		BPF_PROG_TYPE_LWT_XMIT.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- *	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
- *	Description
- *		Store *len* bytes from address *from* into the packet
- *		associated to *skb*, at *offset*. Only the flags, tag and TLVs
- *		inside the outermost IPv6 Segment Routing Header can be
- *		modified through this helper.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- *	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
- *	Description
- *		Adjust the size allocated to TLVs in the outermost IPv6
- *		Segment Routing Header contained in the packet associated to
- *		*skb*, at position *offset* by *delta* bytes. Only offsets
- *		after the segments are accepted. *delta* can be as well
- *		positive (growing) as negative (shrinking).
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- *	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
- *	Description
- *		Apply an IPv6 Segment Routing action of type *action* to the
- *		packet associated to *skb*. Each action takes a parameter
- *		contained at address *param*, and of length *param_len* bytes.
- *		*action* can be one of:
- *
- *		**SEG6_LOCAL_ACTION_END_X**
- *			End.X action: Endpoint with Layer-3 cross-connect.
- *			Type of *param*: **struct in6_addr**.
- *		**SEG6_LOCAL_ACTION_END_T**
- *			End.T action: Endpoint with specific IPv6 table lookup.
- *			Type of *param*: **int**.
- *		**SEG6_LOCAL_ACTION_END_B6**
- *			End.B6 action: Endpoint bound to an SRv6 policy.
- *			Type of param: **struct ipv6_sr_hdr**.
- *		**SEG6_LOCAL_ACTION_END_B6_ENCAP**
- *			End.B6.Encap action: Endpoint bound to an SRv6
- *			encapsulation policy.
- *			Type of param: **struct ipv6_sr_hdr**.
- *
- * 		A call to this helper is susceptible to change the underlaying
- * 		packet buffer. Therefore, at load time, all checks on pointers
- * 		previously done by the verifier are invalidated and must be
- * 		performed again, if the helper is used in combination with
- * 		direct packet access.
- *	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_rc_repeat(void *ctx)
- *	Description
- *		This helper is used in programs implementing IR decoding, to
- *		report a successfully decoded repeat key message. This delays
- *		the generation of a key up event for previously generated
- *		key down event.
- *
- *		Some IR protocols like NEC have a special IR message for
- *		repeating last button, for when a button is held down.
- *
- *		The *ctx* should point to the lirc sample as passed into
- *		the program.
- *
- *		This helper is only available is the kernel was compiled with
- *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
- *		"**y**".
- *	Return
- *		0
- *
- * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
- *	Description
- *		This helper is used in programs implementing IR decoding, to
- *		report a successfully decoded key press with *scancode*,
- *		*toggle* value in the given *protocol*. The scancode will be
- *		translated to a keycode using the rc keymap, and reported as
- *		an input key down event. After a period a key up event is
- *		generated. This period can be extended by calling either
- *		**bpf_rc_keydown**\ () again with the same values, or calling
- *		**bpf_rc_repeat**\ ().
- *
- *		Some protocols include a toggle bit, in case the button	was
- *		released and pressed again between consecutive scancodes.
- *
- *		The *ctx* should point to the lirc sample as passed into
- *		the program.
- *
- *		The *protocol* is the decoded protocol number (see
- *		**enum rc_proto** for some predefined values).
- *
- *		This helper is only available is the kernel was compiled with
- *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
- *		"**y**".
- *	Return
- *		0
- *
- * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
- * 	Description
- * 		Return the cgroup v2 id of the socket associated with the *skb*.
- * 		This is roughly similar to the **bpf_get_cgroup_classid**\ ()
- * 		helper for cgroup v1 by providing a tag resp. identifier that
- * 		can be matched on or used for map lookups e.g. to implement
- * 		policy. The cgroup v2 id of a given path in the hierarchy is
- * 		exposed in user space through the f_handle API in order to get
- * 		to the same 64-bit id.
- *
- * 		This helper can be used on TC egress path, but not on ingress,
- * 		and is available only if the kernel was compiled with the
- * 		**CONFIG_SOCK_CGROUP_DATA** configuration option.
- * 	Return
- * 		The id is returned or 0 in case the id could not be retrieved.
- *
- * u64 bpf_get_current_cgroup_id(void)
- * 	Return
- * 		A 64-bit integer containing the current cgroup id based
- * 		on the cgroup within which the current task is running.
- *
- * void *bpf_get_local_storage(void *map, u64 flags)
- *	Description
- *		Get the pointer to the local storage area.
- *		The type and the size of the local storage is defined
- *		by the *map* argument.
- *		The *flags* meaning is specific for each map type,
- *		and has to be 0 for cgroup local storage.
- *
- *		Depending on the BPF program type, a local storage area
- *		can be shared between multiple instances of the BPF program,
- *		running simultaneously.
- *
- *		A user should care about the synchronization by himself.
- *		For example, by using the **BPF_STX_XADD** instruction to alter
- *		the shared data.
- *	Return
- *		A pointer to the local storage area.
- *
- * int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
- *	Description
- *		Select a **SO_REUSEPORT** socket from a
- *		**BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
- *		It checks the selected socket is matching the incoming
- *		request in the socket buffer.
- *	Return
- *		0 on success, or a negative error in case of failure.
- *
- * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
- *	Description
- *		Return id of cgroup v2 that is ancestor of cgroup associated
- *		with the *skb* at the *ancestor_level*.  The root cgroup is at
- *		*ancestor_level* zero and each step down the hierarchy
- *		increments the level. If *ancestor_level* == level of cgroup
- *		associated with *skb*, then return value will be same as that
- *		of **bpf_skb_cgroup_id**\ ().
- *
- *		The helper is useful to implement policies based on cgroups
- *		that are upper in hierarchy than immediate cgroup associated
- *		with *skb*.
- *
- *		The format of returned id and helper limitations are same as in
- *		**bpf_skb_cgroup_id**\ ().
- *	Return
- *		The id is returned or 0 in case the id could not be retrieved.
- *
- * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
- *	Description
- *		Look for TCP socket matching *tuple*, optionally in a child
- *		network namespace *netns*. The return value must be checked,
- *		and if non-**NULL**, released via **bpf_sk_release**\ ().
- *
- *		The *ctx* should point to the context of the program, such as
- *		the skb or socket (depending on the hook in use). This is used
- *		to determine the base network namespace for the lookup.
- *
- *		*tuple_size* must be one of:
- *
- *		**sizeof**\ (*tuple*\ **->ipv4**)
- *			Look for an IPv4 socket.
- *		**sizeof**\ (*tuple*\ **->ipv6**)
- *			Look for an IPv6 socket.
- *
- *		If the *netns* is a negative signed 32-bit integer, then the
- *		socket lookup table in the netns associated with the *ctx* will
- *		will be used. For the TC hooks, this is the netns of the device
- *		in the skb. For socket hooks, this is the netns of the socket.
- *		If *netns* is any other signed 32-bit value greater than or
- *		equal to zero then it specifies the ID of the netns relative to
- *		the netns associated with the *ctx*. *netns* values beyond the
- *		range of 32-bit integers are reserved for future use.
- *
- *		All values for *flags* are reserved for future usage, and must
- *		be left at zero.
- *
- *		This helper is available only if the kernel was compiled with
- *		**CONFIG_NET** configuration option.
- *	Return
- *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
- *		For sockets with reuseport option, the **struct bpf_sock**
- *		result is from **reuse->socks**\ [] using the hash of the tuple.
- *
- * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
- *	Description
- *		Look for UDP socket matching *tuple*, optionally in a child
- *		network namespace *netns*. The return value must be checked,
- *		and if non-**NULL**, released via **bpf_sk_release**\ ().
- *
- *		The *ctx* should point to the context of the program, such as
- *		the skb or socket (depending on the hook in use). This is used
- *		to determine the base network namespace for the lookup.
- *
- *		*tuple_size* must be one of:
- *
- *		**sizeof**\ (*tuple*\ **->ipv4**)
- *			Look for an IPv4 socket.
- *		**sizeof**\ (*tuple*\ **->ipv6**)
- *			Look for an IPv6 socket.
- *
- *		If the *netns* is a negative signed 32-bit integer, then the
- *		socket lookup table in the netns associated with the *ctx* will
- *		will be used. For the TC hooks, this is the netns of the device
- *		in the skb. For socket hooks, this is the netns of the socket.
- *		If *netns* is any other signed 32-bit value greater than or
- *		equal to zero then it specifies the ID of the netns relative to
- *		the netns associated with the *ctx*. *netns* values beyond the
- *		range of 32-bit integers are reserved for future use.
- *
- *		All values for *flags* are reserved for future usage, and must
- *		be left at zero.
- *
- *		This helper is available only if the kernel was compiled with
- *		**CONFIG_NET** configuration option.
- *	Return
- *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
- *		For sockets with reuseport option, the **struct bpf_sock**
- *		result is from **reuse->socks**\ [] using the hash of the tuple.
- *
- * int bpf_sk_release(struct bpf_sock *sock)
- *	Description
- *		Release the reference held by *sock*. *sock* must be a
- *		non-**NULL** pointer that was returned from
- *		**bpf_sk_lookup_xxx**\ ().
- *	Return
- *		0 on success, or a negative error in case of failure.
- *
- * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
- * 	Description
- * 		Push an element *value* in *map*. *flags* is one of:
- *
- * 		**BPF_EXIST**
- * 			If the queue/stack is full, the oldest element is
- * 			removed to make room for this.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_map_pop_elem(struct bpf_map *map, void *value)
- * 	Description
- * 		Pop an element from *map*.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_map_peek_elem(struct bpf_map *map, void *value)
- * 	Description
- * 		Get an element from *map* without removing it.
- * 	Return
- * 		0 on success, or a negative error in case of failure.
- *
- * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
- *	Description
- *		For socket policies, insert *len* bytes into *msg* at offset
- *		*start*.
- *
- *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
- *		*msg* it may want to insert metadata or options into the *msg*.
- *		This can later be read and used by any of the lower layer BPF
- *		hooks.
- *
- *		This helper may fail if under memory pressure (a malloc
- *		fails) in these cases BPF programs will get an appropriate
- *		error and BPF programs will need to handle them.
- *	Return
- *		0 on success, or a negative error in case of failure.
- *
- * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
- *	Description
- *		Will remove *pop* bytes from a *msg* starting at byte *start*.
- *		This may result in **ENOMEM** errors under certain situations if
- *		an allocation and copy are required due to a full ring buffer.
- *		However, the helper will try to avoid doing the allocation
- *		if possible. Other errors can occur if input parameters are
- *		invalid either due to *start* byte not being valid part of *msg*
- *		payload and/or *pop* value being to large.
- *	Return
- *		0 on success, or a negative error in case of failure.
- *
- * int bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
- *	Description
- *		This helper is used in programs implementing IR decoding, to
- *		report a successfully decoded pointer movement.
- *
- *		The *ctx* should point to the lirc sample as passed into
- *		the program.
- *
- *		This helper is only available is the kernel was compiled with
- *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
- *		"**y**".
- *	Return
- *		0
- *
- * int bpf_spin_lock(struct bpf_spin_lock *lock)
- *	Description
- *		Acquire a spinlock represented by the pointer *lock*, which is
- *		stored as part of a value of a map. Taking the lock allows to
- *		safely update the rest of the fields in that value. The
- *		spinlock can (and must) later be released with a call to
- *		**bpf_spin_unlock**\ (\ *lock*\ ).
- *
- *		Spinlocks in BPF programs come with a number of restrictions
- *		and constraints:
- *
- *		* **bpf_spin_lock** objects are only allowed inside maps of
- *		  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
- *		  list could be extended in the future).
- *		* BTF description of the map is mandatory.
- *		* The BPF program can take ONE lock at a time, since taking two
- *		  or more could cause dead locks.
- *		* Only one **struct bpf_spin_lock** is allowed per map element.
- *		* When the lock is taken, calls (either BPF to BPF or helpers)
- *		  are not allowed.
- *		* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
- *		  allowed inside a spinlock-ed region.
- *		* The BPF program MUST call **bpf_spin_unlock**\ () to release
- *		  the lock, on all execution paths, before it returns.
- *		* The BPF program can access **struct bpf_spin_lock** only via
- *		  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
- *		  helpers. Loading or storing data into the **struct
- *		  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
- *		* To use the **bpf_spin_lock**\ () helper, the BTF description
- *		  of the map value must be a struct and have **struct
- *		  bpf_spin_lock** *anyname*\ **;** field at the top level.
- *		  Nested lock inside another struct is not allowed.
- *		* The **struct bpf_spin_lock** *lock* field in a map value must
- *		  be aligned on a multiple of 4 bytes in that value.
- *		* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
- *		  the **bpf_spin_lock** field to user space.
- *		* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
- *		  a BPF program, do not update the **bpf_spin_lock** field.
- *		* **bpf_spin_lock** cannot be on the stack or inside a
- *		  networking packet (it can only be inside of a map values).
- *		* **bpf_spin_lock** is available to root only.
- *		* Tracing programs and socket filter programs cannot use
- *		  **bpf_spin_lock**\ () due to insufficient preemption checks
- *		  (but this may change in the future).
- *		* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
- *	Return
- *		0
- *
- * int bpf_spin_unlock(struct bpf_spin_lock *lock)
- *	Description
- *		Release the *lock* previously locked by a call to
- *		**bpf_spin_lock**\ (\ *lock*\ ).
- *	Return
- *		0
- *
- * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
- *	Description
- *		This helper gets a **struct bpf_sock** pointer such
- *		that all the fields in this **bpf_sock** can be accessed.
- *	Return
- *		A **struct bpf_sock** pointer on success, or **NULL** in
- *		case of failure.
- *
- * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
- *	Description
- *		This helper gets a **struct bpf_tcp_sock** pointer from a
- *		**struct bpf_sock** pointer.
- *	Return
- *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
- *		case of failure.
- *
- * int bpf_skb_ecn_set_ce(struct sk_buf *skb)
- *	Description
- *		Set ECN (Explicit Congestion Notification) field of IP header
- *		to **CE** (Congestion Encountered) if current value is **ECT**
- *		(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
- *		and IPv4.
- *	Return
- *		1 if the **CE** flag is set (either by the current helper call
- *		or because it was already present), 0 if it is not set.
- *
- * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
- *	Description
- *		Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
- *		**bpf_sk_release**\ () is unnecessary and not allowed.
- *	Return
- *		A **struct bpf_sock** pointer on success, or **NULL** in
- *		case of failure.
- *
- * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
- *	Description
- *		Look for TCP socket matching *tuple*, optionally in a child
- *		network namespace *netns*. The return value must be checked,
- *		and if non-**NULL**, released via **bpf_sk_release**\ ().
- *
- *		This function is identical to bpf_sk_lookup_tcp, except that it
- *		also returns timewait or request sockets. Use bpf_sk_fullsock
- *		or bpf_tcp_socket to access the full structure.
- *
- *		This helper is available only if the kernel was compiled with
- *		**CONFIG_NET** configuration option.
- *	Return
- *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
- *		For sockets with reuseport option, the **struct bpf_sock**
- *		result is from **reuse->socks**\ [] using the hash of the tuple.
- *
- * int bpf_tcp_check_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
- * 	Description
- * 		Check whether iph and th contain a valid SYN cookie ACK for
- * 		the listening socket in sk.
- *
- * 		iph points to the start of the IPv4 or IPv6 header, while
- * 		iph_len contains sizeof(struct iphdr) or sizeof(struct ip6hdr).
- *
- * 		th points to the start of the TCP header, while th_len contains
- * 		sizeof(struct tcphdr).
- *
- * 	Return
- * 		0 if iph and th are a valid SYN cookie ACK, or a negative error
- * 		otherwise.
- */
-#define __BPF_FUNC_MAPPER(FN)		\
-	FN(unspec),			\
-	FN(map_lookup_elem),		\
-	FN(map_update_elem),		\
-	FN(map_delete_elem),		\
-	FN(probe_read),			\
-	FN(ktime_get_ns),		\
-	FN(trace_printk),		\
-	FN(get_prandom_u32),		\
-	FN(get_smp_processor_id),	\
-	FN(skb_store_bytes),		\
-	FN(l3_csum_replace),		\
-	FN(l4_csum_replace),		\
-	FN(tail_call),			\
-	FN(clone_redirect),		\
-	FN(get_current_pid_tgid),	\
-	FN(get_current_uid_gid),	\
-	FN(get_current_comm),		\
-	FN(get_cgroup_classid),		\
-	FN(skb_vlan_push),		\
-	FN(skb_vlan_pop),		\
-	FN(skb_get_tunnel_key),		\
-	FN(skb_set_tunnel_key),		\
-	FN(perf_event_read),		\
-	FN(redirect),			\
-	FN(get_route_realm),		\
-	FN(perf_event_output),		\
-	FN(skb_load_bytes),		\
-	FN(get_stackid),		\
-	FN(csum_diff),			\
-	FN(skb_get_tunnel_opt),		\
-	FN(skb_set_tunnel_opt),		\
-	FN(skb_change_proto),		\
-	FN(skb_change_type),		\
-	FN(skb_under_cgroup),		\
-	FN(get_hash_recalc),		\
-	FN(get_current_task),		\
-	FN(probe_write_user),		\
-	FN(current_task_under_cgroup),	\
-	FN(skb_change_tail),		\
-	FN(skb_pull_data),		\
-	FN(csum_update),		\
-	FN(set_hash_invalid),		\
-	FN(get_numa_node_id),		\
-	FN(skb_change_head),		\
-	FN(xdp_adjust_head),		\
-	FN(probe_read_str),		\
-	FN(get_socket_cookie),		\
-	FN(get_socket_uid),		\
-	FN(set_hash),			\
-	FN(setsockopt),			\
-	FN(skb_adjust_room),		\
-	FN(redirect_map),		\
-	FN(sk_redirect_map),		\
-	FN(sock_map_update),		\
-	FN(xdp_adjust_meta),		\
-	FN(perf_event_read_value),	\
-	FN(perf_prog_read_value),	\
-	FN(getsockopt),			\
-	FN(override_return),		\
-	FN(sock_ops_cb_flags_set),	\
-	FN(msg_redirect_map),		\
-	FN(msg_apply_bytes),		\
-	FN(msg_cork_bytes),		\
-	FN(msg_pull_data),		\
-	FN(bind),			\
-	FN(xdp_adjust_tail),		\
-	FN(skb_get_xfrm_state),		\
-	FN(get_stack),			\
-	FN(skb_load_bytes_relative),	\
-	FN(fib_lookup),			\
-	FN(sock_hash_update),		\
-	FN(msg_redirect_hash),		\
-	FN(sk_redirect_hash),		\
-	FN(lwt_push_encap),		\
-	FN(lwt_seg6_store_bytes),	\
-	FN(lwt_seg6_adjust_srh),	\
-	FN(lwt_seg6_action),		\
-	FN(rc_repeat),			\
-	FN(rc_keydown),			\
-	FN(skb_cgroup_id),		\
-	FN(get_current_cgroup_id),	\
-	FN(get_local_storage),		\
-	FN(sk_select_reuseport),	\
-	FN(skb_ancestor_cgroup_id),	\
-	FN(sk_lookup_tcp),		\
-	FN(sk_lookup_udp),		\
-	FN(sk_release),			\
-	FN(map_push_elem),		\
-	FN(map_pop_elem),		\
-	FN(map_peek_elem),		\
-	FN(msg_push_data),		\
-	FN(msg_pop_data),		\
-	FN(rc_pointer_rel),		\
-	FN(spin_lock),			\
-	FN(spin_unlock),		\
-	FN(sk_fullsock),		\
-	FN(tcp_sock),			\
-	FN(skb_ecn_set_ce),		\
-	FN(get_listener_sock),		\
-	FN(skc_lookup_tcp),		\
-	FN(tcp_check_syncookie),
-
-/* integer value in 'imm' field of BPF_CALL instruction selects which helper
- * function eBPF program intends to call
- */
-#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
-enum bpf_func_id {
-	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
-	__BPF_FUNC_MAX_ID,
-};
-#undef __BPF_ENUM_FN
-
-/* All flags used by eBPF helper functions, placed here. */
-
-/* BPF_FUNC_skb_store_bytes flags. */
-#define BPF_F_RECOMPUTE_CSUM		(1ULL << 0)
-#define BPF_F_INVALIDATE_HASH		(1ULL << 1)
-
-/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
- * First 4 bits are for passing the header field size.
- */
-#define BPF_F_HDR_FIELD_MASK		0xfULL
-
-/* BPF_FUNC_l4_csum_replace flags. */
-#define BPF_F_PSEUDO_HDR		(1ULL << 4)
-#define BPF_F_MARK_MANGLED_0		(1ULL << 5)
-#define BPF_F_MARK_ENFORCE		(1ULL << 6)
-
-/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
-#define BPF_F_INGRESS			(1ULL << 0)
-
-/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
-#define BPF_F_TUNINFO_IPV6		(1ULL << 0)
-
-/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
-#define BPF_F_SKIP_FIELD_MASK		0xffULL
-#define BPF_F_USER_STACK		(1ULL << 8)
-/* flags used by BPF_FUNC_get_stackid only. */
-#define BPF_F_FAST_STACK_CMP		(1ULL << 9)
-#define BPF_F_REUSE_STACKID		(1ULL << 10)
-/* flags used by BPF_FUNC_get_stack only. */
-#define BPF_F_USER_BUILD_ID		(1ULL << 11)
-
-/* BPF_FUNC_skb_set_tunnel_key flags. */
-#define BPF_F_ZERO_CSUM_TX		(1ULL << 1)
-#define BPF_F_DONT_FRAGMENT		(1ULL << 2)
-#define BPF_F_SEQ_NUMBER		(1ULL << 3)
-
-/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
- * BPF_FUNC_perf_event_read_value flags.
- */
-#define BPF_F_INDEX_MASK		0xffffffffULL
-#define BPF_F_CURRENT_CPU		BPF_F_INDEX_MASK
-/* BPF_FUNC_perf_event_output for sk_buff input context. */
-#define BPF_F_CTXLEN_MASK		(0xfffffULL << 32)
-
-/* Current network namespace */
-#define BPF_F_CURRENT_NETNS		(-1L)
-
-/* BPF_FUNC_skb_adjust_room flags. */
-#define BPF_F_ADJ_ROOM_FIXED_GSO	(1ULL << 0)
-
-#define BPF_F_ADJ_ROOM_ENCAP_L3_IPV4	(1ULL << 1)
-#define BPF_F_ADJ_ROOM_ENCAP_L3_IPV6	(1ULL << 2)
-#define BPF_F_ADJ_ROOM_ENCAP_L4_GRE	(1ULL << 3)
-#define BPF_F_ADJ_ROOM_ENCAP_L4_UDP	(1ULL << 4)
-
-/* Mode for BPF_FUNC_skb_adjust_room helper. */
-enum bpf_adj_room_mode {
-	BPF_ADJ_ROOM_NET,
-	BPF_ADJ_ROOM_MAC,
-};
-
-/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
-enum bpf_hdr_start_off {
-	BPF_HDR_START_MAC,
-	BPF_HDR_START_NET,
-};
-
-/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
-enum bpf_lwt_encap_mode {
-	BPF_LWT_ENCAP_SEG6,
-	BPF_LWT_ENCAP_SEG6_INLINE,
-	BPF_LWT_ENCAP_IP,
-};
-
-#define __bpf_md_ptr(type, name)	\
-union {					\
-	type name;			\
-	__u64 :64;			\
-} __attribute__((aligned(8)))
-
-/* user accessible mirror of in-kernel sk_buff.
- * new fields can only be added to the end of this structure
- */
-struct __sk_buff {
-	__u32 len;
-	__u32 pkt_type;
-	__u32 mark;
-	__u32 queue_mapping;
-	__u32 protocol;
-	__u32 vlan_present;
-	__u32 vlan_tci;
-	__u32 vlan_proto;
-	__u32 priority;
-	__u32 ingress_ifindex;
-	__u32 ifindex;
-	__u32 tc_index;
-	__u32 cb[5];
-	__u32 hash;
-	__u32 tc_classid;
-	__u32 data;
-	__u32 data_end;
-	__u32 napi_id;
-
-	/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
-	__u32 family;
-	__u32 remote_ip4;	/* Stored in network byte order */
-	__u32 local_ip4;	/* Stored in network byte order */
-	__u32 remote_ip6[4];	/* Stored in network byte order */
-	__u32 local_ip6[4];	/* Stored in network byte order */
-	__u32 remote_port;	/* Stored in network byte order */
-	__u32 local_port;	/* stored in host byte order */
-	/* ... here. */
-
-	__u32 data_meta;
-	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
-	__u64 tstamp;
-	__u32 wire_len;
-	__u32 gso_segs;
-	__bpf_md_ptr(struct bpf_sock *, sk);
-};
-
-struct bpf_tunnel_key {
-	__u32 tunnel_id;
-	union {
-		__u32 remote_ipv4;
-		__u32 remote_ipv6[4];
-	};
-	__u8 tunnel_tos;
-	__u8 tunnel_ttl;
-	__u16 tunnel_ext;	/* Padding, future use. */
-	__u32 tunnel_label;
-};
-
-/* user accessible mirror of in-kernel xfrm_state.
- * new fields can only be added to the end of this structure
- */
-struct bpf_xfrm_state {
-	__u32 reqid;
-	__u32 spi;	/* Stored in network byte order */
-	__u16 family;
-	__u16 ext;	/* Padding, future use. */
-	union {
-		__u32 remote_ipv4;	/* Stored in network byte order */
-		__u32 remote_ipv6[4];	/* Stored in network byte order */
-	};
-};
-
-/* Generic BPF return codes which all BPF program types may support.
- * The values are binary compatible with their TC_ACT_* counter-part to
- * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
- * programs.
- *
- * XDP is handled seprately, see XDP_*.
- */
-enum bpf_ret_code {
-	BPF_OK = 0,
-	/* 1 reserved */
-	BPF_DROP = 2,
-	/* 3-6 reserved */
-	BPF_REDIRECT = 7,
-	/* >127 are reserved for prog type specific return codes.
-	 *
-	 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
-	 *    BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
-	 *    changed and should be routed based on its new L3 header.
-	 *    (This is an L3 redirect, as opposed to L2 redirect
-	 *    represented by BPF_REDIRECT above).
-	 */
-	BPF_LWT_REROUTE = 128,
-};
-
-struct bpf_sock {
-	__u32 bound_dev_if;
-	__u32 family;
-	__u32 type;
-	__u32 protocol;
-	__u32 mark;
-	__u32 priority;
-	/* IP address also allows 1 and 2 bytes access */
-	__u32 src_ip4;
-	__u32 src_ip6[4];
-	__u32 src_port;		/* host byte order */
-	__u32 dst_port;		/* network byte order */
-	__u32 dst_ip4;
-	__u32 dst_ip6[4];
-	__u32 state;
-};
-
-struct bpf_tcp_sock {
-	__u32 snd_cwnd;		/* Sending congestion window		*/
-	__u32 srtt_us;		/* smoothed round trip time << 3 in usecs */
-	__u32 rtt_min;
-	__u32 snd_ssthresh;	/* Slow start size threshold		*/
-	__u32 rcv_nxt;		/* What we want to receive next		*/
-	__u32 snd_nxt;		/* Next sequence we send		*/
-	__u32 snd_una;		/* First byte we want an ack for	*/
-	__u32 mss_cache;	/* Cached effective mss, not including SACKS */
-	__u32 ecn_flags;	/* ECN status bits.			*/
-	__u32 rate_delivered;	/* saved rate sample: packets delivered */
-	__u32 rate_interval_us;	/* saved rate sample: time elapsed */
-	__u32 packets_out;	/* Packets which are "in flight"	*/
-	__u32 retrans_out;	/* Retransmitted packets out		*/
-	__u32 total_retrans;	/* Total retransmits for entire connection */
-	__u32 segs_in;		/* RFC4898 tcpEStatsPerfSegsIn
-				 * total number of segments in.
-				 */
-	__u32 data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
-				 * total number of data segments in.
-				 */
-	__u32 segs_out;		/* RFC4898 tcpEStatsPerfSegsOut
-				 * The total number of segments sent.
-				 */
-	__u32 data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
-				 * total number of data segments sent.
-				 */
-	__u32 lost_out;		/* Lost packets			*/
-	__u32 sacked_out;	/* SACK'd packets			*/
-	__u64 bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
-				 * sum(delta(rcv_nxt)), or how many bytes
-				 * were acked.
-				 */
-	__u64 bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
-				 * sum(delta(snd_una)), or how many bytes
-				 * were acked.
-				 */
-};
-
-struct bpf_sock_tuple {
-	union {
-		struct {
-			__be32 saddr;
-			__be32 daddr;
-			__be16 sport;
-			__be16 dport;
-		} ipv4;
-		struct {
-			__be32 saddr[4];
-			__be32 daddr[4];
-			__be16 sport;
-			__be16 dport;
-		} ipv6;
-	};
-};
-
-#define XDP_PACKET_HEADROOM 256
-
-/* User return codes for XDP prog type.
- * A valid XDP program must return one of these defined values. All other
- * return codes are reserved for future use. Unknown return codes will
- * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
- */
-enum xdp_action {
-	XDP_ABORTED = 0,
-	XDP_DROP,
-	XDP_PASS,
-	XDP_TX,
-	XDP_REDIRECT,
-};
-
-/* user accessible metadata for XDP packet hook
- * new fields must be added to the end of this structure
- */
-struct xdp_md {
-	__u32 data;
-	__u32 data_end;
-	__u32 data_meta;
-	/* Below access go through struct xdp_rxq_info */
-	__u32 ingress_ifindex; /* rxq->dev->ifindex */
-	__u32 rx_queue_index;  /* rxq->queue_index  */
-};
-
-enum sk_action {
-	SK_DROP = 0,
-	SK_PASS,
-};
-
-/* user accessible metadata for SK_MSG packet hook, new fields must
- * be added to the end of this structure
- */
-struct sk_msg_md {
-	__bpf_md_ptr(void *, data);
-	__bpf_md_ptr(void *, data_end);
-
-	__u32 family;
-	__u32 remote_ip4;	/* Stored in network byte order */
-	__u32 local_ip4;	/* Stored in network byte order */
-	__u32 remote_ip6[4];	/* Stored in network byte order */
-	__u32 local_ip6[4];	/* Stored in network byte order */
-	__u32 remote_port;	/* Stored in network byte order */
-	__u32 local_port;	/* stored in host byte order */
-	__u32 size;		/* Total size of sk_msg */
-};
-
-struct sk_reuseport_md {
-	/*
-	 * Start of directly accessible data. It begins from
-	 * the tcp/udp header.
-	 */
-	__bpf_md_ptr(void *, data);
-	/* End of directly accessible data */
-	__bpf_md_ptr(void *, data_end);
-	/*
-	 * Total length of packet (starting from the tcp/udp header).
-	 * Note that the directly accessible bytes (data_end - data)
-	 * could be less than this "len".  Those bytes could be
-	 * indirectly read by a helper "bpf_skb_load_bytes()".
-	 */
-	__u32 len;
-	/*
-	 * Eth protocol in the mac header (network byte order). e.g.
-	 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
-	 */
-	__u32 eth_protocol;
-	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
-	__u32 bind_inany;	/* Is sock bound to an INANY address? */
-	__u32 hash;		/* A hash of the packet 4 tuples */
-};
-
-#define BPF_TAG_SIZE	8
-
-struct bpf_prog_info {
-	__u32 type;
-	__u32 id;
-	__u8  tag[BPF_TAG_SIZE];
-	__u32 jited_prog_len;
-	__u32 xlated_prog_len;
-	__aligned_u64 jited_prog_insns;
-	__aligned_u64 xlated_prog_insns;
-	__u64 load_time;	/* ns since boottime */
-	__u32 created_by_uid;
-	__u32 nr_map_ids;
-	__aligned_u64 map_ids;
-	char name[BPF_OBJ_NAME_LEN];
-	__u32 ifindex;
-	__u32 gpl_compatible:1;
-	__u64 netns_dev;
-	__u64 netns_ino;
-	__u32 nr_jited_ksyms;
-	__u32 nr_jited_func_lens;
-	__aligned_u64 jited_ksyms;
-	__aligned_u64 jited_func_lens;
-	__u32 btf_id;
-	__u32 func_info_rec_size;
-	__aligned_u64 func_info;
-	__u32 nr_func_info;
-	__u32 nr_line_info;
-	__aligned_u64 line_info;
-	__aligned_u64 jited_line_info;
-	__u32 nr_jited_line_info;
-	__u32 line_info_rec_size;
-	__u32 jited_line_info_rec_size;
-	__u32 nr_prog_tags;
-	__aligned_u64 prog_tags;
-	__u64 run_time_ns;
-	__u64 run_cnt;
-} __attribute__((aligned(8)));
-
-struct bpf_map_info {
-	__u32 type;
-	__u32 id;
-	__u32 key_size;
-	__u32 value_size;
-	__u32 max_entries;
-	__u32 map_flags;
-	char  name[BPF_OBJ_NAME_LEN];
-	__u32 ifindex;
-	__u32 :32;
-	__u64 netns_dev;
-	__u64 netns_ino;
-	__u32 btf_id;
-	__u32 btf_key_type_id;
-	__u32 btf_value_type_id;
-} __attribute__((aligned(8)));
-
-struct bpf_btf_info {
-	__aligned_u64 btf;
-	__u32 btf_size;
-	__u32 id;
-} __attribute__((aligned(8)));
-
-/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
- * by user and intended to be used by socket (e.g. to bind to, depends on
- * attach attach type).
- */
-struct bpf_sock_addr {
-	__u32 user_family;	/* Allows 4-byte read, but no write. */
-	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.
-				 * Stored in network byte order.
-				 */
-	__u32 user_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
-				 * Stored in network byte order.
-				 */
-	__u32 user_port;	/* Allows 4-byte read and write.
-				 * Stored in network byte order
-				 */
-	__u32 family;		/* Allows 4-byte read, but no write */
-	__u32 type;		/* Allows 4-byte read, but no write */
-	__u32 protocol;		/* Allows 4-byte read, but no write */
-	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read an 4-byte write.
-				 * Stored in network byte order.
-				 */
-	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
-				 * Stored in network byte order.
-				 */
-};
-
-/* User bpf_sock_ops struct to access socket values and specify request ops
- * and their replies.
- * Some of this fields are in network (bigendian) byte order and may need
- * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
- * New fields can only be added at the end of this structure
- */
-struct bpf_sock_ops {
-	__u32 op;
-	union {
-		__u32 args[4];		/* Optionally passed to bpf program */
-		__u32 reply;		/* Returned by bpf program	    */
-		__u32 replylong[4];	/* Optionally returned by bpf prog  */
-	};
-	__u32 family;
-	__u32 remote_ip4;	/* Stored in network byte order */
-	__u32 local_ip4;	/* Stored in network byte order */
-	__u32 remote_ip6[4];	/* Stored in network byte order */
-	__u32 local_ip6[4];	/* Stored in network byte order */
-	__u32 remote_port;	/* Stored in network byte order */
-	__u32 local_port;	/* stored in host byte order */
-	__u32 is_fullsock;	/* Some TCP fields are only valid if
-				 * there is a full socket. If not, the
-				 * fields read as zero.
-				 */
-	__u32 snd_cwnd;
-	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
-	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
-	__u32 state;
-	__u32 rtt_min;
-	__u32 snd_ssthresh;
-	__u32 rcv_nxt;
-	__u32 snd_nxt;
-	__u32 snd_una;
-	__u32 mss_cache;
-	__u32 ecn_flags;
-	__u32 rate_delivered;
-	__u32 rate_interval_us;
-	__u32 packets_out;
-	__u32 retrans_out;
-	__u32 total_retrans;
-	__u32 segs_in;
-	__u32 data_segs_in;
-	__u32 segs_out;
-	__u32 data_segs_out;
-	__u32 lost_out;
-	__u32 sacked_out;
-	__u32 sk_txhash;
-	__u64 bytes_received;
-	__u64 bytes_acked;
-};
-
-/* Definitions for bpf_sock_ops_cb_flags */
-#define BPF_SOCK_OPS_RTO_CB_FLAG	(1<<0)
-#define BPF_SOCK_OPS_RETRANS_CB_FLAG	(1<<1)
-#define BPF_SOCK_OPS_STATE_CB_FLAG	(1<<2)
-#define BPF_SOCK_OPS_ALL_CB_FLAGS       0x7		/* Mask of all currently
-							 * supported cb flags
-							 */
-
-/* List of known BPF sock_ops operators.
- * New entries can only be added at the end
- */
-enum {
-	BPF_SOCK_OPS_VOID,
-	BPF_SOCK_OPS_TIMEOUT_INIT,	/* Should return SYN-RTO value to use or
-					 * -1 if default value should be used
-					 */
-	BPF_SOCK_OPS_RWND_INIT,		/* Should return initial advertized
-					 * window (in packets) or -1 if default
-					 * value should be used
-					 */
-	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
-					 * active connection is initialized
-					 */
-	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
-						 * active connection is
-						 * established
-						 */
-	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
-						 * passive connection is
-						 * established
-						 */
-	BPF_SOCK_OPS_NEEDS_ECN,		/* If connection's congestion control
-					 * needs ECN
-					 */
-	BPF_SOCK_OPS_BASE_RTT,		/* Get base RTT. The correct value is
-					 * based on the path and may be
-					 * dependent on the congestion control
-					 * algorithm. In general it indicates
-					 * a congestion threshold. RTTs above
-					 * this indicate congestion
-					 */
-	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
-					 * Arg1: value of icsk_retransmits
-					 * Arg2: value of icsk_rto
-					 * Arg3: whether RTO has expired
-					 */
-	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
-					 * Arg1: sequence number of 1st byte
-					 * Arg2: # segments
-					 * Arg3: return value of
-					 *       tcp_transmit_skb (0 => success)
-					 */
-	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
-					 * Arg1: old_state
-					 * Arg2: new_state
-					 */
-	BPF_SOCK_OPS_TCP_LISTEN_CB,	/* Called on listen(2), right after
-					 * socket transition to LISTEN state.
-					 */
-};
-
-/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
- * changes between the TCP and BPF versions. Ideally this should never happen.
- * If it does, we need to add code to convert them before calling
- * the BPF sock_ops function.
- */
-enum {
-	BPF_TCP_ESTABLISHED = 1,
-	BPF_TCP_SYN_SENT,
-	BPF_TCP_SYN_RECV,
-	BPF_TCP_FIN_WAIT1,
-	BPF_TCP_FIN_WAIT2,
-	BPF_TCP_TIME_WAIT,
-	BPF_TCP_CLOSE,
-	BPF_TCP_CLOSE_WAIT,
-	BPF_TCP_LAST_ACK,
-	BPF_TCP_LISTEN,
-	BPF_TCP_CLOSING,	/* Now a valid state */
-	BPF_TCP_NEW_SYN_RECV,
-
-	BPF_TCP_MAX_STATES	/* Leave at the end! */
-};
-
-#define TCP_BPF_IW		1001	/* Set TCP initial congestion window */
-#define TCP_BPF_SNDCWND_CLAMP	1002	/* Set sndcwnd_clamp */
-
-struct bpf_perf_event_value {
-	__u64 counter;
-	__u64 enabled;
-	__u64 running;
-};
-
-#define BPF_DEVCG_ACC_MKNOD	(1ULL << 0)
-#define BPF_DEVCG_ACC_READ	(1ULL << 1)
-#define BPF_DEVCG_ACC_WRITE	(1ULL << 2)
-
-#define BPF_DEVCG_DEV_BLOCK	(1ULL << 0)
-#define BPF_DEVCG_DEV_CHAR	(1ULL << 1)
-
-struct bpf_cgroup_dev_ctx {
-	/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
-	__u32 access_type;
-	__u32 major;
-	__u32 minor;
-};
-
-struct bpf_raw_tracepoint_args {
-	__u64 args[0];
-};
-
-/* DIRECT:  Skip the FIB rules and go to FIB table associated with device
- * OUTPUT:  Do lookup from egress perspective; default is ingress
- */
-#define BPF_FIB_LOOKUP_DIRECT  BIT(0)
-#define BPF_FIB_LOOKUP_OUTPUT  BIT(1)
-
-enum {
-	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
-	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
-	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
-	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
-	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
-	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
-	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
-	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
-	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
-};
-
-struct bpf_fib_lookup {
-	/* input:  network family for lookup (AF_INET, AF_INET6)
-	 * output: network family of egress nexthop
-	 */
-	__u8	family;
-
-	/* set if lookup is to consider L4 data - e.g., FIB rules */
-	__u8	l4_protocol;
-	__be16	sport;
-	__be16	dport;
-
-	/* total length of packet from network header - used for MTU check */
-	__u16	tot_len;
-
-	/* input: L3 device index for lookup
-	 * output: device index from FIB lookup
-	 */
-	__u32	ifindex;
-
-	union {
-		/* inputs to lookup */
-		__u8	tos;		/* AF_INET  */
-		__be32	flowinfo;	/* AF_INET6, flow_label + priority */
-
-		/* output: metric of fib result (IPv4/IPv6 only) */
-		__u32	rt_metric;
-	};
-
-	union {
-		__be32		ipv4_src;
-		__u32		ipv6_src[4];  /* in6_addr; network order */
-	};
-
-	/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
-	 * network header. output: bpf_fib_lookup sets to gateway address
-	 * if FIB lookup returns gateway route
-	 */
-	union {
-		__be32		ipv4_dst;
-		__u32		ipv6_dst[4];  /* in6_addr; network order */
-	};
-
-	/* output */
-	__be16	h_vlan_proto;
-	__be16	h_vlan_TCI;
-	__u8	smac[6];     /* ETH_ALEN */
-	__u8	dmac[6];     /* ETH_ALEN */
-};
-
-enum bpf_task_fd_type {
-	BPF_FD_TYPE_RAW_TRACEPOINT,	/* tp name */
-	BPF_FD_TYPE_TRACEPOINT,		/* tp name */
-	BPF_FD_TYPE_KPROBE,		/* (symbol + offset) or addr */
-	BPF_FD_TYPE_KRETPROBE,		/* (symbol + offset) or addr */
-	BPF_FD_TYPE_UPROBE,		/* filename + offset */
-	BPF_FD_TYPE_URETPROBE,		/* filename + offset */
-};
-
-struct bpf_flow_keys {
-	__u16	nhoff;
-	__u16	thoff;
-	__u16	addr_proto;			/* ETH_P_* of valid addrs */
-	__u8	is_frag;
-	__u8	is_first_frag;
-	__u8	is_encap;
-	__u8	ip_proto;
-	__be16	n_proto;
-	__be16	sport;
-	__be16	dport;
-	union {
-		struct {
-			__be32	ipv4_src;
-			__be32	ipv4_dst;
-		};
-		struct {
-			__u32	ipv6_src[4];	/* in6_addr; network order */
-			__u32	ipv6_dst[4];	/* in6_addr; network order */
-		};
-	};
-};
-
-struct bpf_func_info {
-	__u32	insn_off;
-	__u32	type_id;
-};
-
-#define BPF_LINE_INFO_LINE_NUM(line_col)	((line_col) >> 10)
-#define BPF_LINE_INFO_LINE_COL(line_col)	((line_col) & 0x3ff)
-
-struct bpf_line_info {
-	__u32	insn_off;
-	__u32	file_name_off;
-	__u32	line_off;
-	__u32	line_col;
-};
-
-struct bpf_spin_lock {
-	__u32	val;
-};
-#endif /* _UAPI__LINUX_BPF_H__ */