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      1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
      2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
      3  *
      4  * This program is free software; you can redistribute it and/or
      5  * modify it under the terms of version 2 of the GNU General Public
      6  * License as published by the Free Software Foundation.
      7  */
      8 #ifndef _UAPI__LINUX_BPF_H__
      9 #define _UAPI__LINUX_BPF_H__
     10 
     11 #include <linux/types.h>
     12 #include <linux/bpf_common.h>
     13 
     14 /* Extended instruction set based on top of classic BPF */
     15 
     16 /* instruction classes */
     17 #define BPF_ALU64	0x07	/* alu mode in double word width */
     18 
     19 /* ld/ldx fields */
     20 #define BPF_DW		0x18	/* double word (64-bit) */
     21 #define BPF_XADD	0xc0	/* exclusive add */
     22 
     23 /* alu/jmp fields */
     24 #define BPF_MOV		0xb0	/* mov reg to reg */
     25 #define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
     26 
     27 /* change endianness of a register */
     28 #define BPF_END		0xd0	/* flags for endianness conversion: */
     29 #define BPF_TO_LE	0x00	/* convert to little-endian */
     30 #define BPF_TO_BE	0x08	/* convert to big-endian */
     31 #define BPF_FROM_LE	BPF_TO_LE
     32 #define BPF_FROM_BE	BPF_TO_BE
     33 
     34 /* jmp encodings */
     35 #define BPF_JNE		0x50	/* jump != */
     36 #define BPF_JLT		0xa0	/* LT is unsigned, '<' */
     37 #define BPF_JLE		0xb0	/* LE is unsigned, '<=' */
     38 #define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
     39 #define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
     40 #define BPF_JSLT	0xc0	/* SLT is signed, '<' */
     41 #define BPF_JSLE	0xd0	/* SLE is signed, '<=' */
     42 #define BPF_CALL	0x80	/* function call */
     43 #define BPF_EXIT	0x90	/* function return */
     44 
     45 /* Register numbers */
     46 enum {
     47 	BPF_REG_0 = 0,
     48 	BPF_REG_1,
     49 	BPF_REG_2,
     50 	BPF_REG_3,
     51 	BPF_REG_4,
     52 	BPF_REG_5,
     53 	BPF_REG_6,
     54 	BPF_REG_7,
     55 	BPF_REG_8,
     56 	BPF_REG_9,
     57 	BPF_REG_10,
     58 	__MAX_BPF_REG,
     59 };
     60 
     61 /* BPF has 10 general purpose 64-bit registers and stack frame. */
     62 #define MAX_BPF_REG	__MAX_BPF_REG
     63 
     64 struct bpf_insn {
     65 	__u8	code;		/* opcode */
     66 	__u8	dst_reg:4;	/* dest register */
     67 	__u8	src_reg:4;	/* source register */
     68 	__s16	off;		/* signed offset */
     69 	__s32	imm;		/* signed immediate constant */
     70 };
     71 
     72 /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
     73 struct bpf_lpm_trie_key {
     74 	__u32	prefixlen;	/* up to 32 for AF_INET, 128 for AF_INET6 */
     75 	__u8	data[0];	/* Arbitrary size */
     76 };
     77 
     78 struct bpf_cgroup_storage_key {
     79 	__u64	cgroup_inode_id;	/* cgroup inode id */
     80 	__u32	attach_type;		/* program attach type */
     81 };
     82 
     83 /* BPF syscall commands, see bpf(2) man-page for details. */
     84 enum bpf_cmd {
     85 	BPF_MAP_CREATE,
     86 	BPF_MAP_LOOKUP_ELEM,
     87 	BPF_MAP_UPDATE_ELEM,
     88 	BPF_MAP_DELETE_ELEM,
     89 	BPF_MAP_GET_NEXT_KEY,
     90 	BPF_PROG_LOAD,
     91 	BPF_OBJ_PIN,
     92 	BPF_OBJ_GET,
     93 	BPF_PROG_ATTACH,
     94 	BPF_PROG_DETACH,
     95 	BPF_PROG_TEST_RUN,
     96 	BPF_PROG_GET_NEXT_ID,
     97 	BPF_MAP_GET_NEXT_ID,
     98 	BPF_PROG_GET_FD_BY_ID,
     99 	BPF_MAP_GET_FD_BY_ID,
    100 	BPF_OBJ_GET_INFO_BY_FD,
    101 	BPF_PROG_QUERY,
    102 	BPF_RAW_TRACEPOINT_OPEN,
    103 	BPF_BTF_LOAD,
    104 	BPF_BTF_GET_FD_BY_ID,
    105 	BPF_TASK_FD_QUERY,
    106 	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
    107 };
    108 
    109 enum bpf_map_type {
    110 	BPF_MAP_TYPE_UNSPEC,
    111 	BPF_MAP_TYPE_HASH,
    112 	BPF_MAP_TYPE_ARRAY,
    113 	BPF_MAP_TYPE_PROG_ARRAY,
    114 	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
    115 	BPF_MAP_TYPE_PERCPU_HASH,
    116 	BPF_MAP_TYPE_PERCPU_ARRAY,
    117 	BPF_MAP_TYPE_STACK_TRACE,
    118 	BPF_MAP_TYPE_CGROUP_ARRAY,
    119 	BPF_MAP_TYPE_LRU_HASH,
    120 	BPF_MAP_TYPE_LRU_PERCPU_HASH,
    121 	BPF_MAP_TYPE_LPM_TRIE,
    122 	BPF_MAP_TYPE_ARRAY_OF_MAPS,
    123 	BPF_MAP_TYPE_HASH_OF_MAPS,
    124 	BPF_MAP_TYPE_DEVMAP,
    125 	BPF_MAP_TYPE_SOCKMAP,
    126 	BPF_MAP_TYPE_CPUMAP,
    127 	BPF_MAP_TYPE_XSKMAP,
    128 	BPF_MAP_TYPE_SOCKHASH,
    129 	BPF_MAP_TYPE_CGROUP_STORAGE,
    130 	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
    131 	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
    132 	BPF_MAP_TYPE_QUEUE,
    133 	BPF_MAP_TYPE_STACK,
    134 };
    135 
    136 /* Note that tracing related programs such as
    137  * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
    138  * are not subject to a stable API since kernel internal data
    139  * structures can change from release to release and may
    140  * therefore break existing tracing BPF programs. Tracing BPF
    141  * programs correspond to /a/ specific kernel which is to be
    142  * analyzed, and not /a/ specific kernel /and/ all future ones.
    143  */
    144 enum bpf_prog_type {
    145 	BPF_PROG_TYPE_UNSPEC,
    146 	BPF_PROG_TYPE_SOCKET_FILTER,
    147 	BPF_PROG_TYPE_KPROBE,
    148 	BPF_PROG_TYPE_SCHED_CLS,
    149 	BPF_PROG_TYPE_SCHED_ACT,
    150 	BPF_PROG_TYPE_TRACEPOINT,
    151 	BPF_PROG_TYPE_XDP,
    152 	BPF_PROG_TYPE_PERF_EVENT,
    153 	BPF_PROG_TYPE_CGROUP_SKB,
    154 	BPF_PROG_TYPE_CGROUP_SOCK,
    155 	BPF_PROG_TYPE_LWT_IN,
    156 	BPF_PROG_TYPE_LWT_OUT,
    157 	BPF_PROG_TYPE_LWT_XMIT,
    158 	BPF_PROG_TYPE_SOCK_OPS,
    159 	BPF_PROG_TYPE_SK_SKB,
    160 	BPF_PROG_TYPE_CGROUP_DEVICE,
    161 	BPF_PROG_TYPE_SK_MSG,
    162 	BPF_PROG_TYPE_RAW_TRACEPOINT,
    163 	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
    164 	BPF_PROG_TYPE_LWT_SEG6LOCAL,
    165 	BPF_PROG_TYPE_LIRC_MODE2,
    166 	BPF_PROG_TYPE_SK_REUSEPORT,
    167 	BPF_PROG_TYPE_FLOW_DISSECTOR,
    168 };
    169 
    170 enum bpf_attach_type {
    171 	BPF_CGROUP_INET_INGRESS,
    172 	BPF_CGROUP_INET_EGRESS,
    173 	BPF_CGROUP_INET_SOCK_CREATE,
    174 	BPF_CGROUP_SOCK_OPS,
    175 	BPF_SK_SKB_STREAM_PARSER,
    176 	BPF_SK_SKB_STREAM_VERDICT,
    177 	BPF_CGROUP_DEVICE,
    178 	BPF_SK_MSG_VERDICT,
    179 	BPF_CGROUP_INET4_BIND,
    180 	BPF_CGROUP_INET6_BIND,
    181 	BPF_CGROUP_INET4_CONNECT,
    182 	BPF_CGROUP_INET6_CONNECT,
    183 	BPF_CGROUP_INET4_POST_BIND,
    184 	BPF_CGROUP_INET6_POST_BIND,
    185 	BPF_CGROUP_UDP4_SENDMSG,
    186 	BPF_CGROUP_UDP6_SENDMSG,
    187 	BPF_LIRC_MODE2,
    188 	BPF_FLOW_DISSECTOR,
    189 	__MAX_BPF_ATTACH_TYPE
    190 };
    191 
    192 #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
    193 
    194 /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
    195  *
    196  * NONE(default): No further bpf programs allowed in the subtree.
    197  *
    198  * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
    199  * the program in this cgroup yields to sub-cgroup program.
    200  *
    201  * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
    202  * that cgroup program gets run in addition to the program in this cgroup.
    203  *
    204  * Only one program is allowed to be attached to a cgroup with
    205  * NONE or BPF_F_ALLOW_OVERRIDE flag.
    206  * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
    207  * release old program and attach the new one. Attach flags has to match.
    208  *
    209  * Multiple programs are allowed to be attached to a cgroup with
    210  * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
    211  * (those that were attached first, run first)
    212  * The programs of sub-cgroup are executed first, then programs of
    213  * this cgroup and then programs of parent cgroup.
    214  * When children program makes decision (like picking TCP CA or sock bind)
    215  * parent program has a chance to override it.
    216  *
    217  * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
    218  * A cgroup with NONE doesn't allow any programs in sub-cgroups.
    219  * Ex1:
    220  * cgrp1 (MULTI progs A, B) ->
    221  *    cgrp2 (OVERRIDE prog C) ->
    222  *      cgrp3 (MULTI prog D) ->
    223  *        cgrp4 (OVERRIDE prog E) ->
    224  *          cgrp5 (NONE prog F)
    225  * the event in cgrp5 triggers execution of F,D,A,B in that order.
    226  * if prog F is detached, the execution is E,D,A,B
    227  * if prog F and D are detached, the execution is E,A,B
    228  * if prog F, E and D are detached, the execution is C,A,B
    229  *
    230  * All eligible programs are executed regardless of return code from
    231  * earlier programs.
    232  */
    233 #define BPF_F_ALLOW_OVERRIDE	(1U << 0)
    234 #define BPF_F_ALLOW_MULTI	(1U << 1)
    235 
    236 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
    237  * verifier will perform strict alignment checking as if the kernel
    238  * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
    239  * and NET_IP_ALIGN defined to 2.
    240  */
    241 #define BPF_F_STRICT_ALIGNMENT	(1U << 0)
    242 
    243 /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
    244  * verifier will allow any alignment whatsoever.  On platforms
    245  * with strict alignment requirements for loads ands stores (such
    246  * as sparc and mips) the verifier validates that all loads and
    247  * stores provably follow this requirement.  This flag turns that
    248  * checking and enforcement off.
    249  *
    250  * It is mostly used for testing when we want to validate the
    251  * context and memory access aspects of the verifier, but because
    252  * of an unaligned access the alignment check would trigger before
    253  * the one we are interested in.
    254  */
    255 #define BPF_F_ANY_ALIGNMENT	(1U << 1)
    256 
    257 /* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
    258 #define BPF_PSEUDO_MAP_FD	1
    259 
    260 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
    261  * offset to another bpf function
    262  */
    263 #define BPF_PSEUDO_CALL		1
    264 
    265 /* flags for BPF_MAP_UPDATE_ELEM command */
    266 #define BPF_ANY		0 /* create new element or update existing */
    267 #define BPF_NOEXIST	1 /* create new element if it didn't exist */
    268 #define BPF_EXIST	2 /* update existing element */
    269 
    270 /* flags for BPF_MAP_CREATE command */
    271 #define BPF_F_NO_PREALLOC	(1U << 0)
    272 /* Instead of having one common LRU list in the
    273  * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
    274  * which can scale and perform better.
    275  * Note, the LRU nodes (including free nodes) cannot be moved
    276  * across different LRU lists.
    277  */
    278 #define BPF_F_NO_COMMON_LRU	(1U << 1)
    279 /* Specify numa node during map creation */
    280 #define BPF_F_NUMA_NODE		(1U << 2)
    281 
    282 #define BPF_OBJ_NAME_LEN 16U
    283 
    284 /* Flags for accessing BPF object */
    285 #define BPF_F_RDONLY		(1U << 3)
    286 #define BPF_F_WRONLY		(1U << 4)
    287 
    288 /* Flag for stack_map, store build_id+offset instead of pointer */
    289 #define BPF_F_STACK_BUILD_ID	(1U << 5)
    290 
    291 /* Zero-initialize hash function seed. This should only be used for testing. */
    292 #define BPF_F_ZERO_SEED		(1U << 6)
    293 
    294 /* flags for BPF_PROG_QUERY */
    295 #define BPF_F_QUERY_EFFECTIVE	(1U << 0)
    296 
    297 enum bpf_stack_build_id_status {
    298 	/* user space need an empty entry to identify end of a trace */
    299 	BPF_STACK_BUILD_ID_EMPTY = 0,
    300 	/* with valid build_id and offset */
    301 	BPF_STACK_BUILD_ID_VALID = 1,
    302 	/* couldn't get build_id, fallback to ip */
    303 	BPF_STACK_BUILD_ID_IP = 2,
    304 };
    305 
    306 #define BPF_BUILD_ID_SIZE 20
    307 struct bpf_stack_build_id {
    308 	__s32		status;
    309 	unsigned char	build_id[BPF_BUILD_ID_SIZE];
    310 	union {
    311 		__u64	offset;
    312 		__u64	ip;
    313 	};
    314 };
    315 
    316 union bpf_attr {
    317 	struct { /* anonymous struct used by BPF_MAP_CREATE command */
    318 		__u32	map_type;	/* one of enum bpf_map_type */
    319 		__u32	key_size;	/* size of key in bytes */
    320 		__u32	value_size;	/* size of value in bytes */
    321 		__u32	max_entries;	/* max number of entries in a map */
    322 		__u32	map_flags;	/* BPF_MAP_CREATE related
    323 					 * flags defined above.
    324 					 */
    325 		__u32	inner_map_fd;	/* fd pointing to the inner map */
    326 		__u32	numa_node;	/* numa node (effective only if
    327 					 * BPF_F_NUMA_NODE is set).
    328 					 */
    329 		char	map_name[BPF_OBJ_NAME_LEN];
    330 		__u32	map_ifindex;	/* ifindex of netdev to create on */
    331 		__u32	btf_fd;		/* fd pointing to a BTF type data */
    332 		__u32	btf_key_type_id;	/* BTF type_id of the key */
    333 		__u32	btf_value_type_id;	/* BTF type_id of the value */
    334 	};
    335 
    336 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
    337 		__u32		map_fd;
    338 		__aligned_u64	key;
    339 		union {
    340 			__aligned_u64 value;
    341 			__aligned_u64 next_key;
    342 		};
    343 		__u64		flags;
    344 	};
    345 
    346 	struct { /* anonymous struct used by BPF_PROG_LOAD command */
    347 		__u32		prog_type;	/* one of enum bpf_prog_type */
    348 		__u32		insn_cnt;
    349 		__aligned_u64	insns;
    350 		__aligned_u64	license;
    351 		__u32		log_level;	/* verbosity level of verifier */
    352 		__u32		log_size;	/* size of user buffer */
    353 		__aligned_u64	log_buf;	/* user supplied buffer */
    354 		__u32		kern_version;	/* not used */
    355 		__u32		prog_flags;
    356 		char		prog_name[BPF_OBJ_NAME_LEN];
    357 		__u32		prog_ifindex;	/* ifindex of netdev to prep for */
    358 		/* For some prog types expected attach type must be known at
    359 		 * load time to verify attach type specific parts of prog
    360 		 * (context accesses, allowed helpers, etc).
    361 		 */
    362 		__u32		expected_attach_type;
    363 		__u32		prog_btf_fd;	/* fd pointing to BTF type data */
    364 		__u32		func_info_rec_size;	/* userspace bpf_func_info size */
    365 		__aligned_u64	func_info;	/* func info */
    366 		__u32		func_info_cnt;	/* number of bpf_func_info records */
    367 		__u32		line_info_rec_size;	/* userspace bpf_line_info size */
    368 		__aligned_u64	line_info;	/* line info */
    369 		__u32		line_info_cnt;	/* number of bpf_line_info records */
    370 	};
    371 
    372 	struct { /* anonymous struct used by BPF_OBJ_* commands */
    373 		__aligned_u64	pathname;
    374 		__u32		bpf_fd;
    375 		__u32		file_flags;
    376 	};
    377 
    378 	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
    379 		__u32		target_fd;	/* container object to attach to */
    380 		__u32		attach_bpf_fd;	/* eBPF program to attach */
    381 		__u32		attach_type;
    382 		__u32		attach_flags;
    383 	};
    384 
    385 	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
    386 		__u32		prog_fd;
    387 		__u32		retval;
    388 		__u32		data_size_in;	/* input: len of data_in */
    389 		__u32		data_size_out;	/* input/output: len of data_out
    390 						 *   returns ENOSPC if data_out
    391 						 *   is too small.
    392 						 */
    393 		__aligned_u64	data_in;
    394 		__aligned_u64	data_out;
    395 		__u32		repeat;
    396 		__u32		duration;
    397 	} test;
    398 
    399 	struct { /* anonymous struct used by BPF_*_GET_*_ID */
    400 		union {
    401 			__u32		start_id;
    402 			__u32		prog_id;
    403 			__u32		map_id;
    404 			__u32		btf_id;
    405 		};
    406 		__u32		next_id;
    407 		__u32		open_flags;
    408 	};
    409 
    410 	struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
    411 		__u32		bpf_fd;
    412 		__u32		info_len;
    413 		__aligned_u64	info;
    414 	} info;
    415 
    416 	struct { /* anonymous struct used by BPF_PROG_QUERY command */
    417 		__u32		target_fd;	/* container object to query */
    418 		__u32		attach_type;
    419 		__u32		query_flags;
    420 		__u32		attach_flags;
    421 		__aligned_u64	prog_ids;
    422 		__u32		prog_cnt;
    423 	} query;
    424 
    425 	struct {
    426 		__u64 name;
    427 		__u32 prog_fd;
    428 	} raw_tracepoint;
    429 
    430 	struct { /* anonymous struct for BPF_BTF_LOAD */
    431 		__aligned_u64	btf;
    432 		__aligned_u64	btf_log_buf;
    433 		__u32		btf_size;
    434 		__u32		btf_log_size;
    435 		__u32		btf_log_level;
    436 	};
    437 
    438 	struct {
    439 		__u32		pid;		/* input: pid */
    440 		__u32		fd;		/* input: fd */
    441 		__u32		flags;		/* input: flags */
    442 		__u32		buf_len;	/* input/output: buf len */
    443 		__aligned_u64	buf;		/* input/output:
    444 						 *   tp_name for tracepoint
    445 						 *   symbol for kprobe
    446 						 *   filename for uprobe
    447 						 */
    448 		__u32		prog_id;	/* output: prod_id */
    449 		__u32		fd_type;	/* output: BPF_FD_TYPE_* */
    450 		__u64		probe_offset;	/* output: probe_offset */
    451 		__u64		probe_addr;	/* output: probe_addr */
    452 	} task_fd_query;
    453 } __attribute__((aligned(8)));
    454 
    455 /* The description below is an attempt at providing documentation to eBPF
    456  * developers about the multiple available eBPF helper functions. It can be
    457  * parsed and used to produce a manual page. The workflow is the following,
    458  * and requires the rst2man utility:
    459  *
    460  *     $ ./scripts/bpf_helpers_doc.py \
    461  *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
    462  *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
    463  *     $ man /tmp/bpf-helpers.7
    464  *
    465  * Note that in order to produce this external documentation, some RST
    466  * formatting is used in the descriptions to get "bold" and "italics" in
    467  * manual pages. Also note that the few trailing white spaces are
    468  * intentional, removing them would break paragraphs for rst2man.
    469  *
    470  * Start of BPF helper function descriptions:
    471  *
    472  * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
    473  * 	Description
    474  * 		Perform a lookup in *map* for an entry associated to *key*.
    475  * 	Return
    476  * 		Map value associated to *key*, or **NULL** if no entry was
    477  * 		found.
    478  *
    479  * int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
    480  * 	Description
    481  * 		Add or update the value of the entry associated to *key* in
    482  * 		*map* with *value*. *flags* is one of:
    483  *
    484  * 		**BPF_NOEXIST**
    485  * 			The entry for *key* must not exist in the map.
    486  * 		**BPF_EXIST**
    487  * 			The entry for *key* must already exist in the map.
    488  * 		**BPF_ANY**
    489  * 			No condition on the existence of the entry for *key*.
    490  *
    491  * 		Flag value **BPF_NOEXIST** cannot be used for maps of types
    492  * 		**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
    493  * 		elements always exist), the helper would return an error.
    494  * 	Return
    495  * 		0 on success, or a negative error in case of failure.
    496  *
    497  * int bpf_map_delete_elem(struct bpf_map *map, const void *key)
    498  * 	Description
    499  * 		Delete entry with *key* from *map*.
    500  * 	Return
    501  * 		0 on success, or a negative error in case of failure.
    502  *
    503  * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
    504  * 	Description
    505  * 		Push an element *value* in *map*. *flags* is one of:
    506  *
    507  * 		**BPF_EXIST**
    508  * 		If the queue/stack is full, the oldest element is removed to
    509  * 		make room for this.
    510  * 	Return
    511  * 		0 on success, or a negative error in case of failure.
    512  *
    513  * int bpf_probe_read(void *dst, u32 size, const void *src)
    514  * 	Description
    515  * 		For tracing programs, safely attempt to read *size* bytes from
    516  * 		address *src* and store the data in *dst*.
    517  * 	Return
    518  * 		0 on success, or a negative error in case of failure.
    519  *
    520  * u64 bpf_ktime_get_ns(void)
    521  * 	Description
    522  * 		Return the time elapsed since system boot, in nanoseconds.
    523  * 	Return
    524  * 		Current *ktime*.
    525  *
    526  * int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
    527  * 	Description
    528  * 		This helper is a "printk()-like" facility for debugging. It
    529  * 		prints a message defined by format *fmt* (of size *fmt_size*)
    530  * 		to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
    531  * 		available. It can take up to three additional **u64**
    532  * 		arguments (as an eBPF helpers, the total number of arguments is
    533  * 		limited to five).
    534  *
    535  * 		Each time the helper is called, it appends a line to the trace.
    536  * 		The format of the trace is customizable, and the exact output
    537  * 		one will get depends on the options set in
    538  * 		*\/sys/kernel/debug/tracing/trace_options* (see also the
    539  * 		*README* file under the same directory). However, it usually
    540  * 		defaults to something like:
    541  *
    542  * 		::
    543  *
    544  * 			telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
    545  *
    546  * 		In the above:
    547  *
    548  * 			* ``telnet`` is the name of the current task.
    549  * 			* ``470`` is the PID of the current task.
    550  * 			* ``001`` is the CPU number on which the task is
    551  * 			  running.
    552  * 			* In ``.N..``, each character refers to a set of
    553  * 			  options (whether irqs are enabled, scheduling
    554  * 			  options, whether hard/softirqs are running, level of
    555  * 			  preempt_disabled respectively). **N** means that
    556  * 			  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
    557  * 			  are set.
    558  * 			* ``419421.045894`` is a timestamp.
    559  * 			* ``0x00000001`` is a fake value used by BPF for the
    560  * 			  instruction pointer register.
    561  * 			* ``<formatted msg>`` is the message formatted with
    562  * 			  *fmt*.
    563  *
    564  * 		The conversion specifiers supported by *fmt* are similar, but
    565  * 		more limited than for printk(). They are **%d**, **%i**,
    566  * 		**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
    567  * 		**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
    568  * 		of field, padding with zeroes, etc.) is available, and the
    569  * 		helper will return **-EINVAL** (but print nothing) if it
    570  * 		encounters an unknown specifier.
    571  *
    572  * 		Also, note that **bpf_trace_printk**\ () is slow, and should
    573  * 		only be used for debugging purposes. For this reason, a notice
    574  * 		bloc (spanning several lines) is printed to kernel logs and
    575  * 		states that the helper should not be used "for production use"
    576  * 		the first time this helper is used (or more precisely, when
    577  * 		**trace_printk**\ () buffers are allocated). For passing values
    578  * 		to user space, perf events should be preferred.
    579  * 	Return
    580  * 		The number of bytes written to the buffer, or a negative error
    581  * 		in case of failure.
    582  *
    583  * u32 bpf_get_prandom_u32(void)
    584  * 	Description
    585  * 		Get a pseudo-random number.
    586  *
    587  * 		From a security point of view, this helper uses its own
    588  * 		pseudo-random internal state, and cannot be used to infer the
    589  * 		seed of other random functions in the kernel. However, it is
    590  * 		essential to note that the generator used by the helper is not
    591  * 		cryptographically secure.
    592  * 	Return
    593  * 		A random 32-bit unsigned value.
    594  *
    595  * u32 bpf_get_smp_processor_id(void)
    596  * 	Description
    597  * 		Get the SMP (symmetric multiprocessing) processor id. Note that
    598  * 		all programs run with preemption disabled, which means that the
    599  * 		SMP processor id is stable during all the execution of the
    600  * 		program.
    601  * 	Return
    602  * 		The SMP id of the processor running the program.
    603  *
    604  * int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
    605  * 	Description
    606  * 		Store *len* bytes from address *from* into the packet
    607  * 		associated to *skb*, at *offset*. *flags* are a combination of
    608  * 		**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
    609  * 		checksum for the packet after storing the bytes) and
    610  * 		**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
    611  * 		**->swhash** and *skb*\ **->l4hash** to 0).
    612  *
    613  * 		A call to this helper is susceptible to change the underlaying
    614  * 		packet buffer. Therefore, at load time, all checks on pointers
    615  * 		previously done by the verifier are invalidated and must be
    616  * 		performed again, if the helper is used in combination with
    617  * 		direct packet access.
    618  * 	Return
    619  * 		0 on success, or a negative error in case of failure.
    620  *
    621  * int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
    622  * 	Description
    623  * 		Recompute the layer 3 (e.g. IP) checksum for the packet
    624  * 		associated to *skb*. Computation is incremental, so the helper
    625  * 		must know the former value of the header field that was
    626  * 		modified (*from*), the new value of this field (*to*), and the
    627  * 		number of bytes (2 or 4) for this field, stored in *size*.
    628  * 		Alternatively, it is possible to store the difference between
    629  * 		the previous and the new values of the header field in *to*, by
    630  * 		setting *from* and *size* to 0. For both methods, *offset*
    631  * 		indicates the location of the IP checksum within the packet.
    632  *
    633  * 		This helper works in combination with **bpf_csum_diff**\ (),
    634  * 		which does not update the checksum in-place, but offers more
    635  * 		flexibility and can handle sizes larger than 2 or 4 for the
    636  * 		checksum to update.
    637  *
    638  * 		A call to this helper is susceptible to change the underlaying
    639  * 		packet buffer. Therefore, at load time, all checks on pointers
    640  * 		previously done by the verifier are invalidated and must be
    641  * 		performed again, if the helper is used in combination with
    642  * 		direct packet access.
    643  * 	Return
    644  * 		0 on success, or a negative error in case of failure.
    645  *
    646  * int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
    647  * 	Description
    648  * 		Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
    649  * 		packet associated to *skb*. Computation is incremental, so the
    650  * 		helper must know the former value of the header field that was
    651  * 		modified (*from*), the new value of this field (*to*), and the
    652  * 		number of bytes (2 or 4) for this field, stored on the lowest
    653  * 		four bits of *flags*. Alternatively, it is possible to store
    654  * 		the difference between the previous and the new values of the
    655  * 		header field in *to*, by setting *from* and the four lowest
    656  * 		bits of *flags* to 0. For both methods, *offset* indicates the
    657  * 		location of the IP checksum within the packet. In addition to
    658  * 		the size of the field, *flags* can be added (bitwise OR) actual
    659  * 		flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
    660  * 		untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
    661  * 		for updates resulting in a null checksum the value is set to
    662  * 		**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
    663  * 		the checksum is to be computed against a pseudo-header.
    664  *
    665  * 		This helper works in combination with **bpf_csum_diff**\ (),
    666  * 		which does not update the checksum in-place, but offers more
    667  * 		flexibility and can handle sizes larger than 2 or 4 for the
    668  * 		checksum to update.
    669  *
    670  * 		A call to this helper is susceptible to change the underlaying
    671  * 		packet buffer. Therefore, at load time, all checks on pointers
    672  * 		previously done by the verifier are invalidated and must be
    673  * 		performed again, if the helper is used in combination with
    674  * 		direct packet access.
    675  * 	Return
    676  * 		0 on success, or a negative error in case of failure.
    677  *
    678  * int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
    679  * 	Description
    680  * 		This special helper is used to trigger a "tail call", or in
    681  * 		other words, to jump into another eBPF program. The same stack
    682  * 		frame is used (but values on stack and in registers for the
    683  * 		caller are not accessible to the callee). This mechanism allows
    684  * 		for program chaining, either for raising the maximum number of
    685  * 		available eBPF instructions, or to execute given programs in
    686  * 		conditional blocks. For security reasons, there is an upper
    687  * 		limit to the number of successive tail calls that can be
    688  * 		performed.
    689  *
    690  * 		Upon call of this helper, the program attempts to jump into a
    691  * 		program referenced at index *index* in *prog_array_map*, a
    692  * 		special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
    693  * 		*ctx*, a pointer to the context.
    694  *
    695  * 		If the call succeeds, the kernel immediately runs the first
    696  * 		instruction of the new program. This is not a function call,
    697  * 		and it never returns to the previous program. If the call
    698  * 		fails, then the helper has no effect, and the caller continues
    699  * 		to run its subsequent instructions. A call can fail if the
    700  * 		destination program for the jump does not exist (i.e. *index*
    701  * 		is superior to the number of entries in *prog_array_map*), or
    702  * 		if the maximum number of tail calls has been reached for this
    703  * 		chain of programs. This limit is defined in the kernel by the
    704  * 		macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
    705  * 		which is currently set to 32.
    706  * 	Return
    707  * 		0 on success, or a negative error in case of failure.
    708  *
    709  * int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
    710  * 	Description
    711  * 		Clone and redirect the packet associated to *skb* to another
    712  * 		net device of index *ifindex*. Both ingress and egress
    713  * 		interfaces can be used for redirection. The **BPF_F_INGRESS**
    714  * 		value in *flags* is used to make the distinction (ingress path
    715  * 		is selected if the flag is present, egress path otherwise).
    716  * 		This is the only flag supported for now.
    717  *
    718  * 		In comparison with **bpf_redirect**\ () helper,
    719  * 		**bpf_clone_redirect**\ () has the associated cost of
    720  * 		duplicating the packet buffer, but this can be executed out of
    721  * 		the eBPF program. Conversely, **bpf_redirect**\ () is more
    722  * 		efficient, but it is handled through an action code where the
    723  * 		redirection happens only after the eBPF program has returned.
    724  *
    725  * 		A call to this helper is susceptible to change the underlaying
    726  * 		packet buffer. Therefore, at load time, all checks on pointers
    727  * 		previously done by the verifier are invalidated and must be
    728  * 		performed again, if the helper is used in combination with
    729  * 		direct packet access.
    730  * 	Return
    731  * 		0 on success, or a negative error in case of failure.
    732  *
    733  * u64 bpf_get_current_pid_tgid(void)
    734  * 	Return
    735  * 		A 64-bit integer containing the current tgid and pid, and
    736  * 		created as such:
    737  * 		*current_task*\ **->tgid << 32 \|**
    738  * 		*current_task*\ **->pid**.
    739  *
    740  * u64 bpf_get_current_uid_gid(void)
    741  * 	Return
    742  * 		A 64-bit integer containing the current GID and UID, and
    743  * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
    744  *
    745  * int bpf_get_current_comm(char *buf, u32 size_of_buf)
    746  * 	Description
    747  * 		Copy the **comm** attribute of the current task into *buf* of
    748  * 		*size_of_buf*. The **comm** attribute contains the name of
    749  * 		the executable (excluding the path) for the current task. The
    750  * 		*size_of_buf* must be strictly positive. On success, the
    751  * 		helper makes sure that the *buf* is NUL-terminated. On failure,
    752  * 		it is filled with zeroes.
    753  * 	Return
    754  * 		0 on success, or a negative error in case of failure.
    755  *
    756  * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
    757  * 	Description
    758  * 		Retrieve the classid for the current task, i.e. for the net_cls
    759  * 		cgroup to which *skb* belongs.
    760  *
    761  * 		This helper can be used on TC egress path, but not on ingress.
    762  *
    763  * 		The net_cls cgroup provides an interface to tag network packets
    764  * 		based on a user-provided identifier for all traffic coming from
    765  * 		the tasks belonging to the related cgroup. See also the related
    766  * 		kernel documentation, available from the Linux sources in file
    767  * 		*Documentation/cgroup-v1/net_cls.txt*.
    768  *
    769  * 		The Linux kernel has two versions for cgroups: there are
    770  * 		cgroups v1 and cgroups v2. Both are available to users, who can
    771  * 		use a mixture of them, but note that the net_cls cgroup is for
    772  * 		cgroup v1 only. This makes it incompatible with BPF programs
    773  * 		run on cgroups, which is a cgroup-v2-only feature (a socket can
    774  * 		only hold data for one version of cgroups at a time).
    775  *
    776  * 		This helper is only available is the kernel was compiled with
    777  * 		the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
    778  * 		"**y**" or to "**m**".
    779  * 	Return
    780  * 		The classid, or 0 for the default unconfigured classid.
    781  *
    782  * int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
    783  * 	Description
    784  * 		Push a *vlan_tci* (VLAN tag control information) of protocol
    785  * 		*vlan_proto* to the packet associated to *skb*, then update
    786  * 		the checksum. Note that if *vlan_proto* is different from
    787  * 		**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
    788  * 		be **ETH_P_8021Q**.
    789  *
    790  * 		A call to this helper is susceptible to change the underlaying
    791  * 		packet buffer. Therefore, at load time, all checks on pointers
    792  * 		previously done by the verifier are invalidated and must be
    793  * 		performed again, if the helper is used in combination with
    794  * 		direct packet access.
    795  * 	Return
    796  * 		0 on success, or a negative error in case of failure.
    797  *
    798  * int bpf_skb_vlan_pop(struct sk_buff *skb)
    799  * 	Description
    800  * 		Pop a VLAN header from the packet associated to *skb*.
    801  *
    802  * 		A call to this helper is susceptible to change the underlaying
    803  * 		packet buffer. Therefore, at load time, all checks on pointers
    804  * 		previously done by the verifier are invalidated and must be
    805  * 		performed again, if the helper is used in combination with
    806  * 		direct packet access.
    807  * 	Return
    808  * 		0 on success, or a negative error in case of failure.
    809  *
    810  * int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
    811  * 	Description
    812  * 		Get tunnel metadata. This helper takes a pointer *key* to an
    813  * 		empty **struct bpf_tunnel_key** of **size**, that will be
    814  * 		filled with tunnel metadata for the packet associated to *skb*.
    815  * 		The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
    816  * 		indicates that the tunnel is based on IPv6 protocol instead of
    817  * 		IPv4.
    818  *
    819  * 		The **struct bpf_tunnel_key** is an object that generalizes the
    820  * 		principal parameters used by various tunneling protocols into a
    821  * 		single struct. This way, it can be used to easily make a
    822  * 		decision based on the contents of the encapsulation header,
    823  * 		"summarized" in this struct. In particular, it holds the IP
    824  * 		address of the remote end (IPv4 or IPv6, depending on the case)
    825  * 		in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
    826  * 		this struct exposes the *key*\ **->tunnel_id**, which is
    827  * 		generally mapped to a VNI (Virtual Network Identifier), making
    828  * 		it programmable together with the **bpf_skb_set_tunnel_key**\
    829  * 		() helper.
    830  *
    831  * 		Let's imagine that the following code is part of a program
    832  * 		attached to the TC ingress interface, on one end of a GRE
    833  * 		tunnel, and is supposed to filter out all messages coming from
    834  * 		remote ends with IPv4 address other than 10.0.0.1:
    835  *
    836  * 		::
    837  *
    838  * 			int ret;
    839  * 			struct bpf_tunnel_key key = {};
    840  *
    841  * 			ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
    842  * 			if (ret < 0)
    843  * 				return TC_ACT_SHOT;	// drop packet
    844  *
    845  * 			if (key.remote_ipv4 != 0x0a000001)
    846  * 				return TC_ACT_SHOT;	// drop packet
    847  *
    848  * 			return TC_ACT_OK;		// accept packet
    849  *
    850  * 		This interface can also be used with all encapsulation devices
    851  * 		that can operate in "collect metadata" mode: instead of having
    852  * 		one network device per specific configuration, the "collect
    853  * 		metadata" mode only requires a single device where the
    854  * 		configuration can be extracted from this helper.
    855  *
    856  * 		This can be used together with various tunnels such as VXLan,
    857  * 		Geneve, GRE or IP in IP (IPIP).
    858  * 	Return
    859  * 		0 on success, or a negative error in case of failure.
    860  *
    861  * int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
    862  * 	Description
    863  * 		Populate tunnel metadata for packet associated to *skb.* The
    864  * 		tunnel metadata is set to the contents of *key*, of *size*. The
    865  * 		*flags* can be set to a combination of the following values:
    866  *
    867  * 		**BPF_F_TUNINFO_IPV6**
    868  * 			Indicate that the tunnel is based on IPv6 protocol
    869  * 			instead of IPv4.
    870  * 		**BPF_F_ZERO_CSUM_TX**
    871  * 			For IPv4 packets, add a flag to tunnel metadata
    872  * 			indicating that checksum computation should be skipped
    873  * 			and checksum set to zeroes.
    874  * 		**BPF_F_DONT_FRAGMENT**
    875  * 			Add a flag to tunnel metadata indicating that the
    876  * 			packet should not be fragmented.
    877  * 		**BPF_F_SEQ_NUMBER**
    878  * 			Add a flag to tunnel metadata indicating that a
    879  * 			sequence number should be added to tunnel header before
    880  * 			sending the packet. This flag was added for GRE
    881  * 			encapsulation, but might be used with other protocols
    882  * 			as well in the future.
    883  *
    884  * 		Here is a typical usage on the transmit path:
    885  *
    886  * 		::
    887  *
    888  * 			struct bpf_tunnel_key key;
    889  * 			     populate key ...
    890  * 			bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
    891  * 			bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
    892  *
    893  * 		See also the description of the **bpf_skb_get_tunnel_key**\ ()
    894  * 		helper for additional information.
    895  * 	Return
    896  * 		0 on success, or a negative error in case of failure.
    897  *
    898  * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
    899  * 	Description
    900  * 		Read the value of a perf event counter. This helper relies on a
    901  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
    902  * 		the perf event counter is selected when *map* is updated with
    903  * 		perf event file descriptors. The *map* is an array whose size
    904  * 		is the number of available CPUs, and each cell contains a value
    905  * 		relative to one CPU. The value to retrieve is indicated by
    906  * 		*flags*, that contains the index of the CPU to look up, masked
    907  * 		with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
    908  * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
    909  * 		current CPU should be retrieved.
    910  *
    911  * 		Note that before Linux 4.13, only hardware perf event can be
    912  * 		retrieved.
    913  *
    914  * 		Also, be aware that the newer helper
    915  * 		**bpf_perf_event_read_value**\ () is recommended over
    916  * 		**bpf_perf_event_read**\ () in general. The latter has some ABI
    917  * 		quirks where error and counter value are used as a return code
    918  * 		(which is wrong to do since ranges may overlap). This issue is
    919  * 		fixed with **bpf_perf_event_read_value**\ (), which at the same
    920  * 		time provides more features over the **bpf_perf_event_read**\
    921  * 		() interface. Please refer to the description of
    922  * 		**bpf_perf_event_read_value**\ () for details.
    923  * 	Return
    924  * 		The value of the perf event counter read from the map, or a
    925  * 		negative error code in case of failure.
    926  *
    927  * int bpf_redirect(u32 ifindex, u64 flags)
    928  * 	Description
    929  * 		Redirect the packet to another net device of index *ifindex*.
    930  * 		This helper is somewhat similar to **bpf_clone_redirect**\
    931  * 		(), except that the packet is not cloned, which provides
    932  * 		increased performance.
    933  *
    934  * 		Except for XDP, both ingress and egress interfaces can be used
    935  * 		for redirection. The **BPF_F_INGRESS** value in *flags* is used
    936  * 		to make the distinction (ingress path is selected if the flag
    937  * 		is present, egress path otherwise). Currently, XDP only
    938  * 		supports redirection to the egress interface, and accepts no
    939  * 		flag at all.
    940  *
    941  * 		The same effect can be attained with the more generic
    942  * 		**bpf_redirect_map**\ (), which requires specific maps to be
    943  * 		used but offers better performance.
    944  * 	Return
    945  * 		For XDP, the helper returns **XDP_REDIRECT** on success or
    946  * 		**XDP_ABORTED** on error. For other program types, the values
    947  * 		are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
    948  * 		error.
    949  *
    950  * u32 bpf_get_route_realm(struct sk_buff *skb)
    951  * 	Description
    952  * 		Retrieve the realm or the route, that is to say the
    953  * 		**tclassid** field of the destination for the *skb*. The
    954  * 		indentifier retrieved is a user-provided tag, similar to the
    955  * 		one used with the net_cls cgroup (see description for
    956  * 		**bpf_get_cgroup_classid**\ () helper), but here this tag is
    957  * 		held by a route (a destination entry), not by a task.
    958  *
    959  * 		Retrieving this identifier works with the clsact TC egress hook
    960  * 		(see also **tc-bpf(8)**), or alternatively on conventional
    961  * 		classful egress qdiscs, but not on TC ingress path. In case of
    962  * 		clsact TC egress hook, this has the advantage that, internally,
    963  * 		the destination entry has not been dropped yet in the transmit
    964  * 		path. Therefore, the destination entry does not need to be
    965  * 		artificially held via **netif_keep_dst**\ () for a classful
    966  * 		qdisc until the *skb* is freed.
    967  *
    968  * 		This helper is available only if the kernel was compiled with
    969  * 		**CONFIG_IP_ROUTE_CLASSID** configuration option.
    970  * 	Return
    971  * 		The realm of the route for the packet associated to *skb*, or 0
    972  * 		if none was found.
    973  *
    974  * int bpf_perf_event_output(struct pt_reg *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
    975  * 	Description
    976  * 		Write raw *data* blob into a special BPF perf event held by
    977  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
    978  * 		event must have the following attributes: **PERF_SAMPLE_RAW**
    979  * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
    980  * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
    981  *
    982  * 		The *flags* are used to indicate the index in *map* for which
    983  * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
    984  * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
    985  * 		to indicate that the index of the current CPU core should be
    986  * 		used.
    987  *
    988  * 		The value to write, of *size*, is passed through eBPF stack and
    989  * 		pointed by *data*.
    990  *
    991  * 		The context of the program *ctx* needs also be passed to the
    992  * 		helper.
    993  *
    994  * 		On user space, a program willing to read the values needs to
    995  * 		call **perf_event_open**\ () on the perf event (either for
    996  * 		one or for all CPUs) and to store the file descriptor into the
    997  * 		*map*. This must be done before the eBPF program can send data
    998  * 		into it. An example is available in file
    999  * 		*samples/bpf/trace_output_user.c* in the Linux kernel source
   1000  * 		tree (the eBPF program counterpart is in
   1001  * 		*samples/bpf/trace_output_kern.c*).
   1002  *
   1003  * 		**bpf_perf_event_output**\ () achieves better performance
   1004  * 		than **bpf_trace_printk**\ () for sharing data with user
   1005  * 		space, and is much better suitable for streaming data from eBPF
   1006  * 		programs.
   1007  *
   1008  * 		Note that this helper is not restricted to tracing use cases
   1009  * 		and can be used with programs attached to TC or XDP as well,
   1010  * 		where it allows for passing data to user space listeners. Data
   1011  * 		can be:
   1012  *
   1013  * 		* Only custom structs,
   1014  * 		* Only the packet payload, or
   1015  * 		* A combination of both.
   1016  * 	Return
   1017  * 		0 on success, or a negative error in case of failure.
   1018  *
   1019  * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
   1020  * 	Description
   1021  * 		This helper was provided as an easy way to load data from a
   1022  * 		packet. It can be used to load *len* bytes from *offset* from
   1023  * 		the packet associated to *skb*, into the buffer pointed by
   1024  * 		*to*.
   1025  *
   1026  * 		Since Linux 4.7, usage of this helper has mostly been replaced
   1027  * 		by "direct packet access", enabling packet data to be
   1028  * 		manipulated with *skb*\ **->data** and *skb*\ **->data_end**
   1029  * 		pointing respectively to the first byte of packet data and to
   1030  * 		the byte after the last byte of packet data. However, it
   1031  * 		remains useful if one wishes to read large quantities of data
   1032  * 		at once from a packet into the eBPF stack.
   1033  * 	Return
   1034  * 		0 on success, or a negative error in case of failure.
   1035  *
   1036  * int bpf_get_stackid(struct pt_reg *ctx, struct bpf_map *map, u64 flags)
   1037  * 	Description
   1038  * 		Walk a user or a kernel stack and return its id. To achieve
   1039  * 		this, the helper needs *ctx*, which is a pointer to the context
   1040  * 		on which the tracing program is executed, and a pointer to a
   1041  * 		*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
   1042  *
   1043  * 		The last argument, *flags*, holds the number of stack frames to
   1044  * 		skip (from 0 to 255), masked with
   1045  * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
   1046  * 		a combination of the following flags:
   1047  *
   1048  * 		**BPF_F_USER_STACK**
   1049  * 			Collect a user space stack instead of a kernel stack.
   1050  * 		**BPF_F_FAST_STACK_CMP**
   1051  * 			Compare stacks by hash only.
   1052  * 		**BPF_F_REUSE_STACKID**
   1053  * 			If two different stacks hash into the same *stackid*,
   1054  * 			discard the old one.
   1055  *
   1056  * 		The stack id retrieved is a 32 bit long integer handle which
   1057  * 		can be further combined with other data (including other stack
   1058  * 		ids) and used as a key into maps. This can be useful for
   1059  * 		generating a variety of graphs (such as flame graphs or off-cpu
   1060  * 		graphs).
   1061  *
   1062  * 		For walking a stack, this helper is an improvement over
   1063  * 		**bpf_probe_read**\ (), which can be used with unrolled loops
   1064  * 		but is not efficient and consumes a lot of eBPF instructions.
   1065  * 		Instead, **bpf_get_stackid**\ () can collect up to
   1066  * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
   1067  * 		this limit can be controlled with the **sysctl** program, and
   1068  * 		that it should be manually increased in order to profile long
   1069  * 		user stacks (such as stacks for Java programs). To do so, use:
   1070  *
   1071  * 		::
   1072  *
   1073  * 			# sysctl kernel.perf_event_max_stack=<new value>
   1074  * 	Return
   1075  * 		The positive or null stack id on success, or a negative error
   1076  * 		in case of failure.
   1077  *
   1078  * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
   1079  * 	Description
   1080  * 		Compute a checksum difference, from the raw buffer pointed by
   1081  * 		*from*, of length *from_size* (that must be a multiple of 4),
   1082  * 		towards the raw buffer pointed by *to*, of size *to_size*
   1083  * 		(same remark). An optional *seed* can be added to the value
   1084  * 		(this can be cascaded, the seed may come from a previous call
   1085  * 		to the helper).
   1086  *
   1087  * 		This is flexible enough to be used in several ways:
   1088  *
   1089  * 		* With *from_size* == 0, *to_size* > 0 and *seed* set to
   1090  * 		  checksum, it can be used when pushing new data.
   1091  * 		* With *from_size* > 0, *to_size* == 0 and *seed* set to
   1092  * 		  checksum, it can be used when removing data from a packet.
   1093  * 		* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
   1094  * 		  can be used to compute a diff. Note that *from_size* and
   1095  * 		  *to_size* do not need to be equal.
   1096  *
   1097  * 		This helper can be used in combination with
   1098  * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
   1099  * 		which one can feed in the difference computed with
   1100  * 		**bpf_csum_diff**\ ().
   1101  * 	Return
   1102  * 		The checksum result, or a negative error code in case of
   1103  * 		failure.
   1104  *
   1105  * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
   1106  * 	Description
   1107  * 		Retrieve tunnel options metadata for the packet associated to
   1108  * 		*skb*, and store the raw tunnel option data to the buffer *opt*
   1109  * 		of *size*.
   1110  *
   1111  * 		This helper can be used with encapsulation devices that can
   1112  * 		operate in "collect metadata" mode (please refer to the related
   1113  * 		note in the description of **bpf_skb_get_tunnel_key**\ () for
   1114  * 		more details). A particular example where this can be used is
   1115  * 		in combination with the Geneve encapsulation protocol, where it
   1116  * 		allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
   1117  * 		and retrieving arbitrary TLVs (Type-Length-Value headers) from
   1118  * 		the eBPF program. This allows for full customization of these
   1119  * 		headers.
   1120  * 	Return
   1121  * 		The size of the option data retrieved.
   1122  *
   1123  * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
   1124  * 	Description
   1125  * 		Set tunnel options metadata for the packet associated to *skb*
   1126  * 		to the option data contained in the raw buffer *opt* of *size*.
   1127  *
   1128  * 		See also the description of the **bpf_skb_get_tunnel_opt**\ ()
   1129  * 		helper for additional information.
   1130  * 	Return
   1131  * 		0 on success, or a negative error in case of failure.
   1132  *
   1133  * int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
   1134  * 	Description
   1135  * 		Change the protocol of the *skb* to *proto*. Currently
   1136  * 		supported are transition from IPv4 to IPv6, and from IPv6 to
   1137  * 		IPv4. The helper takes care of the groundwork for the
   1138  * 		transition, including resizing the socket buffer. The eBPF
   1139  * 		program is expected to fill the new headers, if any, via
   1140  * 		**skb_store_bytes**\ () and to recompute the checksums with
   1141  * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
   1142  * 		(). The main case for this helper is to perform NAT64
   1143  * 		operations out of an eBPF program.
   1144  *
   1145  * 		Internally, the GSO type is marked as dodgy so that headers are
   1146  * 		checked and segments are recalculated by the GSO/GRO engine.
   1147  * 		The size for GSO target is adapted as well.
   1148  *
   1149  * 		All values for *flags* are reserved for future usage, and must
   1150  * 		be left at zero.
   1151  *
   1152  * 		A call to this helper is susceptible to change the underlaying
   1153  * 		packet buffer. Therefore, at load time, all checks on pointers
   1154  * 		previously done by the verifier are invalidated and must be
   1155  * 		performed again, if the helper is used in combination with
   1156  * 		direct packet access.
   1157  * 	Return
   1158  * 		0 on success, or a negative error in case of failure.
   1159  *
   1160  * int bpf_skb_change_type(struct sk_buff *skb, u32 type)
   1161  * 	Description
   1162  * 		Change the packet type for the packet associated to *skb*. This
   1163  * 		comes down to setting *skb*\ **->pkt_type** to *type*, except
   1164  * 		the eBPF program does not have a write access to *skb*\
   1165  * 		**->pkt_type** beside this helper. Using a helper here allows
   1166  * 		for graceful handling of errors.
   1167  *
   1168  * 		The major use case is to change incoming *skb*s to
   1169  * 		**PACKET_HOST** in a programmatic way instead of having to
   1170  * 		recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
   1171  * 		example.
   1172  *
   1173  * 		Note that *type* only allows certain values. At this time, they
   1174  * 		are:
   1175  *
   1176  * 		**PACKET_HOST**
   1177  * 			Packet is for us.
   1178  * 		**PACKET_BROADCAST**
   1179  * 			Send packet to all.
   1180  * 		**PACKET_MULTICAST**
   1181  * 			Send packet to group.
   1182  * 		**PACKET_OTHERHOST**
   1183  * 			Send packet to someone else.
   1184  * 	Return
   1185  * 		0 on success, or a negative error in case of failure.
   1186  *
   1187  * int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
   1188  * 	Description
   1189  * 		Check whether *skb* is a descendant of the cgroup2 held by
   1190  * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
   1191  * 	Return
   1192  * 		The return value depends on the result of the test, and can be:
   1193  *
   1194  * 		* 0, if the *skb* failed the cgroup2 descendant test.
   1195  * 		* 1, if the *skb* succeeded the cgroup2 descendant test.
   1196  * 		* A negative error code, if an error occurred.
   1197  *
   1198  * u32 bpf_get_hash_recalc(struct sk_buff *skb)
   1199  * 	Description
   1200  * 		Retrieve the hash of the packet, *skb*\ **->hash**. If it is
   1201  * 		not set, in particular if the hash was cleared due to mangling,
   1202  * 		recompute this hash. Later accesses to the hash can be done
   1203  * 		directly with *skb*\ **->hash**.
   1204  *
   1205  * 		Calling **bpf_set_hash_invalid**\ (), changing a packet
   1206  * 		prototype with **bpf_skb_change_proto**\ (), or calling
   1207  * 		**bpf_skb_store_bytes**\ () with the
   1208  * 		**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
   1209  * 		the hash and to trigger a new computation for the next call to
   1210  * 		**bpf_get_hash_recalc**\ ().
   1211  * 	Return
   1212  * 		The 32-bit hash.
   1213  *
   1214  * u64 bpf_get_current_task(void)
   1215  * 	Return
   1216  * 		A pointer to the current task struct.
   1217  *
   1218  * int bpf_probe_write_user(void *dst, const void *src, u32 len)
   1219  * 	Description
   1220  * 		Attempt in a safe way to write *len* bytes from the buffer
   1221  * 		*src* to *dst* in memory. It only works for threads that are in
   1222  * 		user context, and *dst* must be a valid user space address.
   1223  *
   1224  * 		This helper should not be used to implement any kind of
   1225  * 		security mechanism because of TOC-TOU attacks, but rather to
   1226  * 		debug, divert, and manipulate execution of semi-cooperative
   1227  * 		processes.
   1228  *
   1229  * 		Keep in mind that this feature is meant for experiments, and it
   1230  * 		has a risk of crashing the system and running programs.
   1231  * 		Therefore, when an eBPF program using this helper is attached,
   1232  * 		a warning including PID and process name is printed to kernel
   1233  * 		logs.
   1234  * 	Return
   1235  * 		0 on success, or a negative error in case of failure.
   1236  *
   1237  * int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
   1238  * 	Description
   1239  * 		Check whether the probe is being run is the context of a given
   1240  * 		subset of the cgroup2 hierarchy. The cgroup2 to test is held by
   1241  * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
   1242  * 	Return
   1243  * 		The return value depends on the result of the test, and can be:
   1244  *
   1245  * 		* 0, if the *skb* task belongs to the cgroup2.
   1246  * 		* 1, if the *skb* task does not belong to the cgroup2.
   1247  * 		* A negative error code, if an error occurred.
   1248  *
   1249  * int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
   1250  * 	Description
   1251  * 		Resize (trim or grow) the packet associated to *skb* to the
   1252  * 		new *len*. The *flags* are reserved for future usage, and must
   1253  * 		be left at zero.
   1254  *
   1255  * 		The basic idea is that the helper performs the needed work to
   1256  * 		change the size of the packet, then the eBPF program rewrites
   1257  * 		the rest via helpers like **bpf_skb_store_bytes**\ (),
   1258  * 		**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
   1259  * 		and others. This helper is a slow path utility intended for
   1260  * 		replies with control messages. And because it is targeted for
   1261  * 		slow path, the helper itself can afford to be slow: it
   1262  * 		implicitly linearizes, unclones and drops offloads from the
   1263  * 		*skb*.
   1264  *
   1265  * 		A call to this helper is susceptible to change the underlaying
   1266  * 		packet buffer. Therefore, at load time, all checks on pointers
   1267  * 		previously done by the verifier are invalidated and must be
   1268  * 		performed again, if the helper is used in combination with
   1269  * 		direct packet access.
   1270  * 	Return
   1271  * 		0 on success, or a negative error in case of failure.
   1272  *
   1273  * int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
   1274  * 	Description
   1275  * 		Pull in non-linear data in case the *skb* is non-linear and not
   1276  * 		all of *len* are part of the linear section. Make *len* bytes
   1277  * 		from *skb* readable and writable. If a zero value is passed for
   1278  * 		*len*, then the whole length of the *skb* is pulled.
   1279  *
   1280  * 		This helper is only needed for reading and writing with direct
   1281  * 		packet access.
   1282  *
   1283  * 		For direct packet access, testing that offsets to access
   1284  * 		are within packet boundaries (test on *skb*\ **->data_end**) is
   1285  * 		susceptible to fail if offsets are invalid, or if the requested
   1286  * 		data is in non-linear parts of the *skb*. On failure the
   1287  * 		program can just bail out, or in the case of a non-linear
   1288  * 		buffer, use a helper to make the data available. The
   1289  * 		**bpf_skb_load_bytes**\ () helper is a first solution to access
   1290  * 		the data. Another one consists in using **bpf_skb_pull_data**
   1291  * 		to pull in once the non-linear parts, then retesting and
   1292  * 		eventually access the data.
   1293  *
   1294  * 		At the same time, this also makes sure the *skb* is uncloned,
   1295  * 		which is a necessary condition for direct write. As this needs
   1296  * 		to be an invariant for the write part only, the verifier
   1297  * 		detects writes and adds a prologue that is calling
   1298  * 		**bpf_skb_pull_data()** to effectively unclone the *skb* from
   1299  * 		the very beginning in case it is indeed cloned.
   1300  *
   1301  * 		A call to this helper is susceptible to change the underlaying
   1302  * 		packet buffer. Therefore, at load time, all checks on pointers
   1303  * 		previously done by the verifier are invalidated and must be
   1304  * 		performed again, if the helper is used in combination with
   1305  * 		direct packet access.
   1306  * 	Return
   1307  * 		0 on success, or a negative error in case of failure.
   1308  *
   1309  * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
   1310  * 	Description
   1311  * 		Add the checksum *csum* into *skb*\ **->csum** in case the
   1312  * 		driver has supplied a checksum for the entire packet into that
   1313  * 		field. Return an error otherwise. This helper is intended to be
   1314  * 		used in combination with **bpf_csum_diff**\ (), in particular
   1315  * 		when the checksum needs to be updated after data has been
   1316  * 		written into the packet through direct packet access.
   1317  * 	Return
   1318  * 		The checksum on success, or a negative error code in case of
   1319  * 		failure.
   1320  *
   1321  * void bpf_set_hash_invalid(struct sk_buff *skb)
   1322  * 	Description
   1323  * 		Invalidate the current *skb*\ **->hash**. It can be used after
   1324  * 		mangling on headers through direct packet access, in order to
   1325  * 		indicate that the hash is outdated and to trigger a
   1326  * 		recalculation the next time the kernel tries to access this
   1327  * 		hash or when the **bpf_get_hash_recalc**\ () helper is called.
   1328  *
   1329  * int bpf_get_numa_node_id(void)
   1330  * 	Description
   1331  * 		Return the id of the current NUMA node. The primary use case
   1332  * 		for this helper is the selection of sockets for the local NUMA
   1333  * 		node, when the program is attached to sockets using the
   1334  * 		**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
   1335  * 		but the helper is also available to other eBPF program types,
   1336  * 		similarly to **bpf_get_smp_processor_id**\ ().
   1337  * 	Return
   1338  * 		The id of current NUMA node.
   1339  *
   1340  * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
   1341  * 	Description
   1342  * 		Grows headroom of packet associated to *skb* and adjusts the
   1343  * 		offset of the MAC header accordingly, adding *len* bytes of
   1344  * 		space. It automatically extends and reallocates memory as
   1345  * 		required.
   1346  *
   1347  * 		This helper can be used on a layer 3 *skb* to push a MAC header
   1348  * 		for redirection into a layer 2 device.
   1349  *
   1350  * 		All values for *flags* are reserved for future usage, and must
   1351  * 		be left at zero.
   1352  *
   1353  * 		A call to this helper is susceptible to change the underlaying
   1354  * 		packet buffer. Therefore, at load time, all checks on pointers
   1355  * 		previously done by the verifier are invalidated and must be
   1356  * 		performed again, if the helper is used in combination with
   1357  * 		direct packet access.
   1358  * 	Return
   1359  * 		0 on success, or a negative error in case of failure.
   1360  *
   1361  * int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
   1362  * 	Description
   1363  * 		Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
   1364  * 		it is possible to use a negative value for *delta*. This helper
   1365  * 		can be used to prepare the packet for pushing or popping
   1366  * 		headers.
   1367  *
   1368  * 		A call to this helper is susceptible to change the underlaying
   1369  * 		packet buffer. Therefore, at load time, all checks on pointers
   1370  * 		previously done by the verifier are invalidated and must be
   1371  * 		performed again, if the helper is used in combination with
   1372  * 		direct packet access.
   1373  * 	Return
   1374  * 		0 on success, or a negative error in case of failure.
   1375  *
   1376  * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
   1377  * 	Description
   1378  * 		Copy a NUL terminated string from an unsafe address
   1379  * 		*unsafe_ptr* to *dst*. The *size* should include the
   1380  * 		terminating NUL byte. In case the string length is smaller than
   1381  * 		*size*, the target is not padded with further NUL bytes. If the
   1382  * 		string length is larger than *size*, just *size*-1 bytes are
   1383  * 		copied and the last byte is set to NUL.
   1384  *
   1385  * 		On success, the length of the copied string is returned. This
   1386  * 		makes this helper useful in tracing programs for reading
   1387  * 		strings, and more importantly to get its length at runtime. See
   1388  * 		the following snippet:
   1389  *
   1390  * 		::
   1391  *
   1392  * 			SEC("kprobe/sys_open")
   1393  * 			void bpf_sys_open(struct pt_regs *ctx)
   1394  * 			{
   1395  * 			        char buf[PATHLEN]; // PATHLEN is defined to 256
   1396  * 			        int res = bpf_probe_read_str(buf, sizeof(buf),
   1397  * 				                             ctx->di);
   1398  *
   1399  * 				// Consume buf, for example push it to
   1400  * 				// userspace via bpf_perf_event_output(); we
   1401  * 				// can use res (the string length) as event
   1402  * 				// size, after checking its boundaries.
   1403  * 			}
   1404  *
   1405  * 		In comparison, using **bpf_probe_read()** helper here instead
   1406  * 		to read the string would require to estimate the length at
   1407  * 		compile time, and would often result in copying more memory
   1408  * 		than necessary.
   1409  *
   1410  * 		Another useful use case is when parsing individual process
   1411  * 		arguments or individual environment variables navigating
   1412  * 		*current*\ **->mm->arg_start** and *current*\
   1413  * 		**->mm->env_start**: using this helper and the return value,
   1414  * 		one can quickly iterate at the right offset of the memory area.
   1415  * 	Return
   1416  * 		On success, the strictly positive length of the string,
   1417  * 		including the trailing NUL character. On error, a negative
   1418  * 		value.
   1419  *
   1420  * u64 bpf_get_socket_cookie(struct sk_buff *skb)
   1421  * 	Description
   1422  * 		If the **struct sk_buff** pointed by *skb* has a known socket,
   1423  * 		retrieve the cookie (generated by the kernel) of this socket.
   1424  * 		If no cookie has been set yet, generate a new cookie. Once
   1425  * 		generated, the socket cookie remains stable for the life of the
   1426  * 		socket. This helper can be useful for monitoring per socket
   1427  * 		networking traffic statistics as it provides a unique socket
   1428  * 		identifier per namespace.
   1429  * 	Return
   1430  * 		A 8-byte long non-decreasing number on success, or 0 if the
   1431  * 		socket field is missing inside *skb*.
   1432  *
   1433  * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
   1434  * 	Description
   1435  * 		Equivalent to bpf_get_socket_cookie() helper that accepts
   1436  * 		*skb*, but gets socket from **struct bpf_sock_addr** contex.
   1437  * 	Return
   1438  * 		A 8-byte long non-decreasing number.
   1439  *
   1440  * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
   1441  * 	Description
   1442  * 		Equivalent to bpf_get_socket_cookie() helper that accepts
   1443  * 		*skb*, but gets socket from **struct bpf_sock_ops** contex.
   1444  * 	Return
   1445  * 		A 8-byte long non-decreasing number.
   1446  *
   1447  * u32 bpf_get_socket_uid(struct sk_buff *skb)
   1448  * 	Return
   1449  * 		The owner UID of the socket associated to *skb*. If the socket
   1450  * 		is **NULL**, or if it is not a full socket (i.e. if it is a
   1451  * 		time-wait or a request socket instead), **overflowuid** value
   1452  * 		is returned (note that **overflowuid** might also be the actual
   1453  * 		UID value for the socket).
   1454  *
   1455  * u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
   1456  * 	Description
   1457  * 		Set the full hash for *skb* (set the field *skb*\ **->hash**)
   1458  * 		to value *hash*.
   1459  * 	Return
   1460  * 		0
   1461  *
   1462  * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
   1463  * 	Description
   1464  * 		Emulate a call to **setsockopt()** on the socket associated to
   1465  * 		*bpf_socket*, which must be a full socket. The *level* at
   1466  * 		which the option resides and the name *optname* of the option
   1467  * 		must be specified, see **setsockopt(2)** for more information.
   1468  * 		The option value of length *optlen* is pointed by *optval*.
   1469  *
   1470  * 		This helper actually implements a subset of **setsockopt()**.
   1471  * 		It supports the following *level*\ s:
   1472  *
   1473  * 		* **SOL_SOCKET**, which supports the following *optname*\ s:
   1474  * 		  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
   1475  * 		  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
   1476  * 		* **IPPROTO_TCP**, which supports the following *optname*\ s:
   1477  * 		  **TCP_CONGESTION**, **TCP_BPF_IW**,
   1478  * 		  **TCP_BPF_SNDCWND_CLAMP**.
   1479  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
   1480  * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
   1481  * 	Return
   1482  * 		0 on success, or a negative error in case of failure.
   1483  *
   1484  * int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
   1485  * 	Description
   1486  * 		Grow or shrink the room for data in the packet associated to
   1487  * 		*skb* by *len_diff*, and according to the selected *mode*.
   1488  *
   1489  * 		There is a single supported mode at this time:
   1490  *
   1491  * 		* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
   1492  * 		  (room space is added or removed below the layer 3 header).
   1493  *
   1494  * 		All values for *flags* are reserved for future usage, and must
   1495  * 		be left at zero.
   1496  *
   1497  * 		A call to this helper is susceptible to change the underlaying
   1498  * 		packet buffer. Therefore, at load time, all checks on pointers
   1499  * 		previously done by the verifier are invalidated and must be
   1500  * 		performed again, if the helper is used in combination with
   1501  * 		direct packet access.
   1502  * 	Return
   1503  * 		0 on success, or a negative error in case of failure.
   1504  *
   1505  * int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
   1506  * 	Description
   1507  * 		Redirect the packet to the endpoint referenced by *map* at
   1508  * 		index *key*. Depending on its type, this *map* can contain
   1509  * 		references to net devices (for forwarding packets through other
   1510  * 		ports), or to CPUs (for redirecting XDP frames to another CPU;
   1511  * 		but this is only implemented for native XDP (with driver
   1512  * 		support) as of this writing).
   1513  *
   1514  * 		All values for *flags* are reserved for future usage, and must
   1515  * 		be left at zero.
   1516  *
   1517  * 		When used to redirect packets to net devices, this helper
   1518  * 		provides a high performance increase over **bpf_redirect**\ ().
   1519  * 		This is due to various implementation details of the underlying
   1520  * 		mechanisms, one of which is the fact that **bpf_redirect_map**\
   1521  * 		() tries to send packet as a "bulk" to the device.
   1522  * 	Return
   1523  * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
   1524  *
   1525  * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
   1526  * 	Description
   1527  * 		Redirect the packet to the socket referenced by *map* (of type
   1528  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
   1529  * 		egress interfaces can be used for redirection. The
   1530  * 		**BPF_F_INGRESS** value in *flags* is used to make the
   1531  * 		distinction (ingress path is selected if the flag is present,
   1532  * 		egress path otherwise). This is the only flag supported for now.
   1533  * 	Return
   1534  * 		**SK_PASS** on success, or **SK_DROP** on error.
   1535  *
   1536  * int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
   1537  * 	Description
   1538  * 		Add an entry to, or update a *map* referencing sockets. The
   1539  * 		*skops* is used as a new value for the entry associated to
   1540  * 		*key*. *flags* is one of:
   1541  *
   1542  * 		**BPF_NOEXIST**
   1543  * 			The entry for *key* must not exist in the map.
   1544  * 		**BPF_EXIST**
   1545  * 			The entry for *key* must already exist in the map.
   1546  * 		**BPF_ANY**
   1547  * 			No condition on the existence of the entry for *key*.
   1548  *
   1549  * 		If the *map* has eBPF programs (parser and verdict), those will
   1550  * 		be inherited by the socket being added. If the socket is
   1551  * 		already attached to eBPF programs, this results in an error.
   1552  * 	Return
   1553  * 		0 on success, or a negative error in case of failure.
   1554  *
   1555  * int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
   1556  * 	Description
   1557  * 		Adjust the address pointed by *xdp_md*\ **->data_meta** by
   1558  * 		*delta* (which can be positive or negative). Note that this
   1559  * 		operation modifies the address stored in *xdp_md*\ **->data**,
   1560  * 		so the latter must be loaded only after the helper has been
   1561  * 		called.
   1562  *
   1563  * 		The use of *xdp_md*\ **->data_meta** is optional and programs
   1564  * 		are not required to use it. The rationale is that when the
   1565  * 		packet is processed with XDP (e.g. as DoS filter), it is
   1566  * 		possible to push further meta data along with it before passing
   1567  * 		to the stack, and to give the guarantee that an ingress eBPF
   1568  * 		program attached as a TC classifier on the same device can pick
   1569  * 		this up for further post-processing. Since TC works with socket
   1570  * 		buffers, it remains possible to set from XDP the **mark** or
   1571  * 		**priority** pointers, or other pointers for the socket buffer.
   1572  * 		Having this scratch space generic and programmable allows for
   1573  * 		more flexibility as the user is free to store whatever meta
   1574  * 		data they need.
   1575  *
   1576  * 		A call to this helper is susceptible to change the underlaying
   1577  * 		packet buffer. Therefore, at load time, all checks on pointers
   1578  * 		previously done by the verifier are invalidated and must be
   1579  * 		performed again, if the helper is used in combination with
   1580  * 		direct packet access.
   1581  * 	Return
   1582  * 		0 on success, or a negative error in case of failure.
   1583  *
   1584  * int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
   1585  * 	Description
   1586  * 		Read the value of a perf event counter, and store it into *buf*
   1587  * 		of size *buf_size*. This helper relies on a *map* of type
   1588  * 		**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
   1589  * 		counter is selected when *map* is updated with perf event file
   1590  * 		descriptors. The *map* is an array whose size is the number of
   1591  * 		available CPUs, and each cell contains a value relative to one
   1592  * 		CPU. The value to retrieve is indicated by *flags*, that
   1593  * 		contains the index of the CPU to look up, masked with
   1594  * 		**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
   1595  * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
   1596  * 		current CPU should be retrieved.
   1597  *
   1598  * 		This helper behaves in a way close to
   1599  * 		**bpf_perf_event_read**\ () helper, save that instead of
   1600  * 		just returning the value observed, it fills the *buf*
   1601  * 		structure. This allows for additional data to be retrieved: in
   1602  * 		particular, the enabled and running times (in *buf*\
   1603  * 		**->enabled** and *buf*\ **->running**, respectively) are
   1604  * 		copied. In general, **bpf_perf_event_read_value**\ () is
   1605  * 		recommended over **bpf_perf_event_read**\ (), which has some
   1606  * 		ABI issues and provides fewer functionalities.
   1607  *
   1608  * 		These values are interesting, because hardware PMU (Performance
   1609  * 		Monitoring Unit) counters are limited resources. When there are
   1610  * 		more PMU based perf events opened than available counters,
   1611  * 		kernel will multiplex these events so each event gets certain
   1612  * 		percentage (but not all) of the PMU time. In case that
   1613  * 		multiplexing happens, the number of samples or counter value
   1614  * 		will not reflect the case compared to when no multiplexing
   1615  * 		occurs. This makes comparison between different runs difficult.
   1616  * 		Typically, the counter value should be normalized before
   1617  * 		comparing to other experiments. The usual normalization is done
   1618  * 		as follows.
   1619  *
   1620  * 		::
   1621  *
   1622  * 			normalized_counter = counter * t_enabled / t_running
   1623  *
   1624  * 		Where t_enabled is the time enabled for event and t_running is
   1625  * 		the time running for event since last normalization. The
   1626  * 		enabled and running times are accumulated since the perf event
   1627  * 		open. To achieve scaling factor between two invocations of an
   1628  * 		eBPF program, users can can use CPU id as the key (which is
   1629  * 		typical for perf array usage model) to remember the previous
   1630  * 		value and do the calculation inside the eBPF program.
   1631  * 	Return
   1632  * 		0 on success, or a negative error in case of failure.
   1633  *
   1634  * int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
   1635  * 	Description
   1636  * 		For en eBPF program attached to a perf event, retrieve the
   1637  * 		value of the event counter associated to *ctx* and store it in
   1638  * 		the structure pointed by *buf* and of size *buf_size*. Enabled
   1639  * 		and running times are also stored in the structure (see
   1640  * 		description of helper **bpf_perf_event_read_value**\ () for
   1641  * 		more details).
   1642  * 	Return
   1643  * 		0 on success, or a negative error in case of failure.
   1644  *
   1645  * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
   1646  * 	Description
   1647  * 		Emulate a call to **getsockopt()** on the socket associated to
   1648  * 		*bpf_socket*, which must be a full socket. The *level* at
   1649  * 		which the option resides and the name *optname* of the option
   1650  * 		must be specified, see **getsockopt(2)** for more information.
   1651  * 		The retrieved value is stored in the structure pointed by
   1652  * 		*opval* and of length *optlen*.
   1653  *
   1654  * 		This helper actually implements a subset of **getsockopt()**.
   1655  * 		It supports the following *level*\ s:
   1656  *
   1657  * 		* **IPPROTO_TCP**, which supports *optname*
   1658  * 		  **TCP_CONGESTION**.
   1659  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
   1660  * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
   1661  * 	Return
   1662  * 		0 on success, or a negative error in case of failure.
   1663  *
   1664  * int bpf_override_return(struct pt_reg *regs, u64 rc)
   1665  * 	Description
   1666  * 		Used for error injection, this helper uses kprobes to override
   1667  * 		the return value of the probed function, and to set it to *rc*.
   1668  * 		The first argument is the context *regs* on which the kprobe
   1669  * 		works.
   1670  *
   1671  * 		This helper works by setting setting the PC (program counter)
   1672  * 		to an override function which is run in place of the original
   1673  * 		probed function. This means the probed function is not run at
   1674  * 		all. The replacement function just returns with the required
   1675  * 		value.
   1676  *
   1677  * 		This helper has security implications, and thus is subject to
   1678  * 		restrictions. It is only available if the kernel was compiled
   1679  * 		with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
   1680  * 		option, and in this case it only works on functions tagged with
   1681  * 		**ALLOW_ERROR_INJECTION** in the kernel code.
   1682  *
   1683  * 		Also, the helper is only available for the architectures having
   1684  * 		the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
   1685  * 		x86 architecture is the only one to support this feature.
   1686  * 	Return
   1687  * 		0
   1688  *
   1689  * int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
   1690  * 	Description
   1691  * 		Attempt to set the value of the **bpf_sock_ops_cb_flags** field
   1692  * 		for the full TCP socket associated to *bpf_sock_ops* to
   1693  * 		*argval*.
   1694  *
   1695  * 		The primary use of this field is to determine if there should
   1696  * 		be calls to eBPF programs of type
   1697  * 		**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
   1698  * 		code. A program of the same type can change its value, per
   1699  * 		connection and as necessary, when the connection is
   1700  * 		established. This field is directly accessible for reading, but
   1701  * 		this helper must be used for updates in order to return an
   1702  * 		error if an eBPF program tries to set a callback that is not
   1703  * 		supported in the current kernel.
   1704  *
   1705  * 		The supported callback values that *argval* can combine are:
   1706  *
   1707  * 		* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
   1708  * 		* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
   1709  * 		* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
   1710  *
   1711  * 		Here are some examples of where one could call such eBPF
   1712  * 		program:
   1713  *
   1714  * 		* When RTO fires.
   1715  * 		* When a packet is retransmitted.
   1716  * 		* When the connection terminates.
   1717  * 		* When a packet is sent.
   1718  * 		* When a packet is received.
   1719  * 	Return
   1720  * 		Code **-EINVAL** if the socket is not a full TCP socket;
   1721  * 		otherwise, a positive number containing the bits that could not
   1722  * 		be set is returned (which comes down to 0 if all bits were set
   1723  * 		as required).
   1724  *
   1725  * int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
   1726  * 	Description
   1727  * 		This helper is used in programs implementing policies at the
   1728  * 		socket level. If the message *msg* is allowed to pass (i.e. if
   1729  * 		the verdict eBPF program returns **SK_PASS**), redirect it to
   1730  * 		the socket referenced by *map* (of type
   1731  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
   1732  * 		egress interfaces can be used for redirection. The
   1733  * 		**BPF_F_INGRESS** value in *flags* is used to make the
   1734  * 		distinction (ingress path is selected if the flag is present,
   1735  * 		egress path otherwise). This is the only flag supported for now.
   1736  * 	Return
   1737  * 		**SK_PASS** on success, or **SK_DROP** on error.
   1738  *
   1739  * int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
   1740  * 	Description
   1741  * 		For socket policies, apply the verdict of the eBPF program to
   1742  * 		the next *bytes* (number of bytes) of message *msg*.
   1743  *
   1744  * 		For example, this helper can be used in the following cases:
   1745  *
   1746  * 		* A single **sendmsg**\ () or **sendfile**\ () system call
   1747  * 		  contains multiple logical messages that the eBPF program is
   1748  * 		  supposed to read and for which it should apply a verdict.
   1749  * 		* An eBPF program only cares to read the first *bytes* of a
   1750  * 		  *msg*. If the message has a large payload, then setting up
   1751  * 		  and calling the eBPF program repeatedly for all bytes, even
   1752  * 		  though the verdict is already known, would create unnecessary
   1753  * 		  overhead.
   1754  *
   1755  * 		When called from within an eBPF program, the helper sets a
   1756  * 		counter internal to the BPF infrastructure, that is used to
   1757  * 		apply the last verdict to the next *bytes*. If *bytes* is
   1758  * 		smaller than the current data being processed from a
   1759  * 		**sendmsg**\ () or **sendfile**\ () system call, the first
   1760  * 		*bytes* will be sent and the eBPF program will be re-run with
   1761  * 		the pointer for start of data pointing to byte number *bytes*
   1762  * 		**+ 1**. If *bytes* is larger than the current data being
   1763  * 		processed, then the eBPF verdict will be applied to multiple
   1764  * 		**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
   1765  * 		consumed.
   1766  *
   1767  * 		Note that if a socket closes with the internal counter holding
   1768  * 		a non-zero value, this is not a problem because data is not
   1769  * 		being buffered for *bytes* and is sent as it is received.
   1770  * 	Return
   1771  * 		0
   1772  *
   1773  * int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
   1774  * 	Description
   1775  * 		For socket policies, prevent the execution of the verdict eBPF
   1776  * 		program for message *msg* until *bytes* (byte number) have been
   1777  * 		accumulated.
   1778  *
   1779  * 		This can be used when one needs a specific number of bytes
   1780  * 		before a verdict can be assigned, even if the data spans
   1781  * 		multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
   1782  * 		case would be a user calling **sendmsg**\ () repeatedly with
   1783  * 		1-byte long message segments. Obviously, this is bad for
   1784  * 		performance, but it is still valid. If the eBPF program needs
   1785  * 		*bytes* bytes to validate a header, this helper can be used to
   1786  * 		prevent the eBPF program to be called again until *bytes* have
   1787  * 		been accumulated.
   1788  * 	Return
   1789  * 		0
   1790  *
   1791  * int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
   1792  * 	Description
   1793  * 		For socket policies, pull in non-linear data from user space
   1794  * 		for *msg* and set pointers *msg*\ **->data** and *msg*\
   1795  * 		**->data_end** to *start* and *end* bytes offsets into *msg*,
   1796  * 		respectively.
   1797  *
   1798  * 		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
   1799  * 		*msg* it can only parse data that the (**data**, **data_end**)
   1800  * 		pointers have already consumed. For **sendmsg**\ () hooks this
   1801  * 		is likely the first scatterlist element. But for calls relying
   1802  * 		on the **sendpage** handler (e.g. **sendfile**\ ()) this will
   1803  * 		be the range (**0**, **0**) because the data is shared with
   1804  * 		user space and by default the objective is to avoid allowing
   1805  * 		user space to modify data while (or after) eBPF verdict is
   1806  * 		being decided. This helper can be used to pull in data and to
   1807  * 		set the start and end pointer to given values. Data will be
   1808  * 		copied if necessary (i.e. if data was not linear and if start
   1809  * 		and end pointers do not point to the same chunk).
   1810  *
   1811  * 		A call to this helper is susceptible to change the underlaying
   1812  * 		packet buffer. Therefore, at load time, all checks on pointers
   1813  * 		previously done by the verifier are invalidated and must be
   1814  * 		performed again, if the helper is used in combination with
   1815  * 		direct packet access.
   1816  *
   1817  * 		All values for *flags* are reserved for future usage, and must
   1818  * 		be left at zero.
   1819  * 	Return
   1820  * 		0 on success, or a negative error in case of failure.
   1821  *
   1822  * int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
   1823  * 	Description
   1824  * 		Bind the socket associated to *ctx* to the address pointed by
   1825  * 		*addr*, of length *addr_len*. This allows for making outgoing
   1826  * 		connection from the desired IP address, which can be useful for
   1827  * 		example when all processes inside a cgroup should use one
   1828  * 		single IP address on a host that has multiple IP configured.
   1829  *
   1830  * 		This helper works for IPv4 and IPv6, TCP and UDP sockets. The
   1831  * 		domain (*addr*\ **->sa_family**) must be **AF_INET** (or
   1832  * 		**AF_INET6**). Looking for a free port to bind to can be
   1833  * 		expensive, therefore binding to port is not permitted by the
   1834  * 		helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
   1835  * 		must be set to zero.
   1836  * 	Return
   1837  * 		0 on success, or a negative error in case of failure.
   1838  *
   1839  * int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
   1840  * 	Description
   1841  * 		Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
   1842  * 		only possible to shrink the packet as of this writing,
   1843  * 		therefore *delta* must be a negative integer.
   1844  *
   1845  * 		A call to this helper is susceptible to change the underlaying
   1846  * 		packet buffer. Therefore, at load time, all checks on pointers
   1847  * 		previously done by the verifier are invalidated and must be
   1848  * 		performed again, if the helper is used in combination with
   1849  * 		direct packet access.
   1850  * 	Return
   1851  * 		0 on success, or a negative error in case of failure.
   1852  *
   1853  * int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
   1854  * 	Description
   1855  * 		Retrieve the XFRM state (IP transform framework, see also
   1856  * 		**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
   1857  *
   1858  * 		The retrieved value is stored in the **struct bpf_xfrm_state**
   1859  * 		pointed by *xfrm_state* and of length *size*.
   1860  *
   1861  * 		All values for *flags* are reserved for future usage, and must
   1862  * 		be left at zero.
   1863  *
   1864  * 		This helper is available only if the kernel was compiled with
   1865  * 		**CONFIG_XFRM** configuration option.
   1866  * 	Return
   1867  * 		0 on success, or a negative error in case of failure.
   1868  *
   1869  * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
   1870  * 	Description
   1871  * 		Return a user or a kernel stack in bpf program provided buffer.
   1872  * 		To achieve this, the helper needs *ctx*, which is a pointer
   1873  * 		to the context on which the tracing program is executed.
   1874  * 		To store the stacktrace, the bpf program provides *buf* with
   1875  * 		a nonnegative *size*.
   1876  *
   1877  * 		The last argument, *flags*, holds the number of stack frames to
   1878  * 		skip (from 0 to 255), masked with
   1879  * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
   1880  * 		the following flags:
   1881  *
   1882  * 		**BPF_F_USER_STACK**
   1883  * 			Collect a user space stack instead of a kernel stack.
   1884  * 		**BPF_F_USER_BUILD_ID**
   1885  * 			Collect buildid+offset instead of ips for user stack,
   1886  * 			only valid if **BPF_F_USER_STACK** is also specified.
   1887  *
   1888  * 		**bpf_get_stack**\ () can collect up to
   1889  * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
   1890  * 		to sufficient large buffer size. Note that
   1891  * 		this limit can be controlled with the **sysctl** program, and
   1892  * 		that it should be manually increased in order to profile long
   1893  * 		user stacks (such as stacks for Java programs). To do so, use:
   1894  *
   1895  * 		::
   1896  *
   1897  * 			# sysctl kernel.perf_event_max_stack=<new value>
   1898  * 	Return
   1899  * 		A non-negative value equal to or less than *size* on success,
   1900  * 		or a negative error in case of failure.
   1901  *
   1902  * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
   1903  * 	Description
   1904  * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
   1905  * 		it provides an easy way to load *len* bytes from *offset*
   1906  * 		from the packet associated to *skb*, into the buffer pointed
   1907  * 		by *to*. The difference to **bpf_skb_load_bytes**\ () is that
   1908  * 		a fifth argument *start_header* exists in order to select a
   1909  * 		base offset to start from. *start_header* can be one of:
   1910  *
   1911  * 		**BPF_HDR_START_MAC**
   1912  * 			Base offset to load data from is *skb*'s mac header.
   1913  * 		**BPF_HDR_START_NET**
   1914  * 			Base offset to load data from is *skb*'s network header.
   1915  *
   1916  * 		In general, "direct packet access" is the preferred method to
   1917  * 		access packet data, however, this helper is in particular useful
   1918  * 		in socket filters where *skb*\ **->data** does not always point
   1919  * 		to the start of the mac header and where "direct packet access"
   1920  * 		is not available.
   1921  * 	Return
   1922  * 		0 on success, or a negative error in case of failure.
   1923  *
   1924  * int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
   1925  *	Description
   1926  *		Do FIB lookup in kernel tables using parameters in *params*.
   1927  *		If lookup is successful and result shows packet is to be
   1928  *		forwarded, the neighbor tables are searched for the nexthop.
   1929  *		If successful (ie., FIB lookup shows forwarding and nexthop
   1930  *		is resolved), the nexthop address is returned in ipv4_dst
   1931  *		or ipv6_dst based on family, smac is set to mac address of
   1932  *		egress device, dmac is set to nexthop mac address, rt_metric
   1933  *		is set to metric from route (IPv4/IPv6 only), and ifindex
   1934  *		is set to the device index of the nexthop from the FIB lookup.
   1935  *
   1936  *		*plen* argument is the size of the passed in struct.
   1937  *		*flags* argument can be a combination of one or more of the
   1938  *		following values:
   1939  *
   1940  *		**BPF_FIB_LOOKUP_DIRECT**
   1941  *			Do a direct table lookup vs full lookup using FIB
   1942  *			rules.
   1943  *		**BPF_FIB_LOOKUP_OUTPUT**
   1944  *			Perform lookup from an egress perspective (default is
   1945  *			ingress).
   1946  *
   1947  *		*ctx* is either **struct xdp_md** for XDP programs or
   1948  *		**struct sk_buff** tc cls_act programs.
   1949  *	Return
   1950  *		* < 0 if any input argument is invalid
   1951  *		*   0 on success (packet is forwarded, nexthop neighbor exists)
   1952  *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
   1953  *		  packet is not forwarded or needs assist from full stack
   1954  *
   1955  * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
   1956  *	Description
   1957  *		Add an entry to, or update a sockhash *map* referencing sockets.
   1958  *		The *skops* is used as a new value for the entry associated to
   1959  *		*key*. *flags* is one of:
   1960  *
   1961  *		**BPF_NOEXIST**
   1962  *			The entry for *key* must not exist in the map.
   1963  *		**BPF_EXIST**
   1964  *			The entry for *key* must already exist in the map.
   1965  *		**BPF_ANY**
   1966  *			No condition on the existence of the entry for *key*.
   1967  *
   1968  *		If the *map* has eBPF programs (parser and verdict), those will
   1969  *		be inherited by the socket being added. If the socket is
   1970  *		already attached to eBPF programs, this results in an error.
   1971  *	Return
   1972  *		0 on success, or a negative error in case of failure.
   1973  *
   1974  * int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
   1975  *	Description
   1976  *		This helper is used in programs implementing policies at the
   1977  *		socket level. If the message *msg* is allowed to pass (i.e. if
   1978  *		the verdict eBPF program returns **SK_PASS**), redirect it to
   1979  *		the socket referenced by *map* (of type
   1980  *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
   1981  *		egress interfaces can be used for redirection. The
   1982  *		**BPF_F_INGRESS** value in *flags* is used to make the
   1983  *		distinction (ingress path is selected if the flag is present,
   1984  *		egress path otherwise). This is the only flag supported for now.
   1985  *	Return
   1986  *		**SK_PASS** on success, or **SK_DROP** on error.
   1987  *
   1988  * int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
   1989  *	Description
   1990  *		This helper is used in programs implementing policies at the
   1991  *		skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
   1992  *		if the verdeict eBPF program returns **SK_PASS**), redirect it
   1993  *		to the socket referenced by *map* (of type
   1994  *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
   1995  *		egress interfaces can be used for redirection. The
   1996  *		**BPF_F_INGRESS** value in *flags* is used to make the
   1997  *		distinction (ingress path is selected if the flag is present,
   1998  *		egress otherwise). This is the only flag supported for now.
   1999  *	Return
   2000  *		**SK_PASS** on success, or **SK_DROP** on error.
   2001  *
   2002  * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
   2003  *	Description
   2004  *		Encapsulate the packet associated to *skb* within a Layer 3
   2005  *		protocol header. This header is provided in the buffer at
   2006  *		address *hdr*, with *len* its size in bytes. *type* indicates
   2007  *		the protocol of the header and can be one of:
   2008  *
   2009  *		**BPF_LWT_ENCAP_SEG6**
   2010  *			IPv6 encapsulation with Segment Routing Header
   2011  *			(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
   2012  *			the IPv6 header is computed by the kernel.
   2013  *		**BPF_LWT_ENCAP_SEG6_INLINE**
   2014  *			Only works if *skb* contains an IPv6 packet. Insert a
   2015  *			Segment Routing Header (**struct ipv6_sr_hdr**) inside
   2016  *			the IPv6 header.
   2017  *
   2018  * 		A call to this helper is susceptible to change the underlaying
   2019  * 		packet buffer. Therefore, at load time, all checks on pointers
   2020  * 		previously done by the verifier are invalidated and must be
   2021  * 		performed again, if the helper is used in combination with
   2022  * 		direct packet access.
   2023  *	Return
   2024  * 		0 on success, or a negative error in case of failure.
   2025  *
   2026  * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
   2027  *	Description
   2028  *		Store *len* bytes from address *from* into the packet
   2029  *		associated to *skb*, at *offset*. Only the flags, tag and TLVs
   2030  *		inside the outermost IPv6 Segment Routing Header can be
   2031  *		modified through this helper.
   2032  *
   2033  * 		A call to this helper is susceptible to change the underlaying
   2034  * 		packet buffer. Therefore, at load time, all checks on pointers
   2035  * 		previously done by the verifier are invalidated and must be
   2036  * 		performed again, if the helper is used in combination with
   2037  * 		direct packet access.
   2038  *	Return
   2039  * 		0 on success, or a negative error in case of failure.
   2040  *
   2041  * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
   2042  *	Description
   2043  *		Adjust the size allocated to TLVs in the outermost IPv6
   2044  *		Segment Routing Header contained in the packet associated to
   2045  *		*skb*, at position *offset* by *delta* bytes. Only offsets
   2046  *		after the segments are accepted. *delta* can be as well
   2047  *		positive (growing) as negative (shrinking).
   2048  *
   2049  * 		A call to this helper is susceptible to change the underlaying
   2050  * 		packet buffer. Therefore, at load time, all checks on pointers
   2051  * 		previously done by the verifier are invalidated and must be
   2052  * 		performed again, if the helper is used in combination with
   2053  * 		direct packet access.
   2054  *	Return
   2055  * 		0 on success, or a negative error in case of failure.
   2056  *
   2057  * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
   2058  *	Description
   2059  *		Apply an IPv6 Segment Routing action of type *action* to the
   2060  *		packet associated to *skb*. Each action takes a parameter
   2061  *		contained at address *param*, and of length *param_len* bytes.
   2062  *		*action* can be one of:
   2063  *
   2064  *		**SEG6_LOCAL_ACTION_END_X**
   2065  *			End.X action: Endpoint with Layer-3 cross-connect.
   2066  *			Type of *param*: **struct in6_addr**.
   2067  *		**SEG6_LOCAL_ACTION_END_T**
   2068  *			End.T action: Endpoint with specific IPv6 table lookup.
   2069  *			Type of *param*: **int**.
   2070  *		**SEG6_LOCAL_ACTION_END_B6**
   2071  *			End.B6 action: Endpoint bound to an SRv6 policy.
   2072  *			Type of param: **struct ipv6_sr_hdr**.
   2073  *		**SEG6_LOCAL_ACTION_END_B6_ENCAP**
   2074  *			End.B6.Encap action: Endpoint bound to an SRv6
   2075  *			encapsulation policy.
   2076  *			Type of param: **struct ipv6_sr_hdr**.
   2077  *
   2078  * 		A call to this helper is susceptible to change the underlaying
   2079  * 		packet buffer. Therefore, at load time, all checks on pointers
   2080  * 		previously done by the verifier are invalidated and must be
   2081  * 		performed again, if the helper is used in combination with
   2082  * 		direct packet access.
   2083  *	Return
   2084  * 		0 on success, or a negative error in case of failure.
   2085  *
   2086  * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
   2087  *	Description
   2088  *		This helper is used in programs implementing IR decoding, to
   2089  *		report a successfully decoded key press with *scancode*,
   2090  *		*toggle* value in the given *protocol*. The scancode will be
   2091  *		translated to a keycode using the rc keymap, and reported as
   2092  *		an input key down event. After a period a key up event is
   2093  *		generated. This period can be extended by calling either
   2094  *		**bpf_rc_keydown**\ () again with the same values, or calling
   2095  *		**bpf_rc_repeat**\ ().
   2096  *
   2097  *		Some protocols include a toggle bit, in case the button	was
   2098  *		released and pressed again between consecutive scancodes.
   2099  *
   2100  *		The *ctx* should point to the lirc sample as passed into
   2101  *		the program.
   2102  *
   2103  *		The *protocol* is the decoded protocol number (see
   2104  *		**enum rc_proto** for some predefined values).
   2105  *
   2106  *		This helper is only available is the kernel was compiled with
   2107  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
   2108  *		"**y**".
   2109  *	Return
   2110  *		0
   2111  *
   2112  * int bpf_rc_repeat(void *ctx)
   2113  *	Description
   2114  *		This helper is used in programs implementing IR decoding, to
   2115  *		report a successfully decoded repeat key message. This delays
   2116  *		the generation of a key up event for previously generated
   2117  *		key down event.
   2118  *
   2119  *		Some IR protocols like NEC have a special IR message for
   2120  *		repeating last button, for when a button is held down.
   2121  *
   2122  *		The *ctx* should point to the lirc sample as passed into
   2123  *		the program.
   2124  *
   2125  *		This helper is only available is the kernel was compiled with
   2126  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
   2127  *		"**y**".
   2128  *	Return
   2129  *		0
   2130  *
   2131  * uint64_t bpf_skb_cgroup_id(struct sk_buff *skb)
   2132  * 	Description
   2133  * 		Return the cgroup v2 id of the socket associated with the *skb*.
   2134  * 		This is roughly similar to the **bpf_get_cgroup_classid**\ ()
   2135  * 		helper for cgroup v1 by providing a tag resp. identifier that
   2136  * 		can be matched on or used for map lookups e.g. to implement
   2137  * 		policy. The cgroup v2 id of a given path in the hierarchy is
   2138  * 		exposed in user space through the f_handle API in order to get
   2139  * 		to the same 64-bit id.
   2140  *
   2141  * 		This helper can be used on TC egress path, but not on ingress,
   2142  * 		and is available only if the kernel was compiled with the
   2143  * 		**CONFIG_SOCK_CGROUP_DATA** configuration option.
   2144  * 	Return
   2145  * 		The id is returned or 0 in case the id could not be retrieved.
   2146  *
   2147  * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
   2148  *	Description
   2149  *		Return id of cgroup v2 that is ancestor of cgroup associated
   2150  *		with the *skb* at the *ancestor_level*.  The root cgroup is at
   2151  *		*ancestor_level* zero and each step down the hierarchy
   2152  *		increments the level. If *ancestor_level* == level of cgroup
   2153  *		associated with *skb*, then return value will be same as that
   2154  *		of **bpf_skb_cgroup_id**\ ().
   2155  *
   2156  *		The helper is useful to implement policies based on cgroups
   2157  *		that are upper in hierarchy than immediate cgroup associated
   2158  *		with *skb*.
   2159  *
   2160  *		The format of returned id and helper limitations are same as in
   2161  *		**bpf_skb_cgroup_id**\ ().
   2162  *	Return
   2163  *		The id is returned or 0 in case the id could not be retrieved.
   2164  *
   2165  * u64 bpf_get_current_cgroup_id(void)
   2166  * 	Return
   2167  * 		A 64-bit integer containing the current cgroup id based
   2168  * 		on the cgroup within which the current task is running.
   2169  *
   2170  * void* get_local_storage(void *map, u64 flags)
   2171  *	Description
   2172  *		Get the pointer to the local storage area.
   2173  *		The type and the size of the local storage is defined
   2174  *		by the *map* argument.
   2175  *		The *flags* meaning is specific for each map type,
   2176  *		and has to be 0 for cgroup local storage.
   2177  *
   2178  *		Depending on the BPF program type, a local storage area
   2179  *		can be shared between multiple instances of the BPF program,
   2180  *		running simultaneously.
   2181  *
   2182  *		A user should care about the synchronization by himself.
   2183  *		For example, by using the **BPF_STX_XADD** instruction to alter
   2184  *		the shared data.
   2185  *	Return
   2186  *		A pointer to the local storage area.
   2187  *
   2188  * int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
   2189  *	Description
   2190  *		Select a **SO_REUSEPORT** socket from a
   2191  *		**BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
   2192  *		It checks the selected socket is matching the incoming
   2193  *		request in the socket buffer.
   2194  *	Return
   2195  *		0 on success, or a negative error in case of failure.
   2196  *
   2197  * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
   2198  *	Description
   2199  *		Look for TCP socket matching *tuple*, optionally in a child
   2200  *		network namespace *netns*. The return value must be checked,
   2201  *		and if non-**NULL**, released via **bpf_sk_release**\ ().
   2202  *
   2203  *		The *ctx* should point to the context of the program, such as
   2204  *		the skb or socket (depending on the hook in use). This is used
   2205  *		to determine the base network namespace for the lookup.
   2206  *
   2207  *		*tuple_size* must be one of:
   2208  *
   2209  *		**sizeof**\ (*tuple*\ **->ipv4**)
   2210  *			Look for an IPv4 socket.
   2211  *		**sizeof**\ (*tuple*\ **->ipv6**)
   2212  *			Look for an IPv6 socket.
   2213  *
   2214  *		If the *netns* is a negative signed 32-bit integer, then the
   2215  *		socket lookup table in the netns associated with the *ctx* will
   2216  *		will be used. For the TC hooks, this is the netns of the device
   2217  *		in the skb. For socket hooks, this is the netns of the socket.
   2218  *		If *netns* is any other signed 32-bit value greater than or
   2219  *		equal to zero then it specifies the ID of the netns relative to
   2220  *		the netns associated with the *ctx*. *netns* values beyond the
   2221  *		range of 32-bit integers are reserved for future use.
   2222  *
   2223  *		All values for *flags* are reserved for future usage, and must
   2224  *		be left at zero.
   2225  *
   2226  *		This helper is available only if the kernel was compiled with
   2227  *		**CONFIG_NET** configuration option.
   2228  *	Return
   2229  *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
   2230  *		For sockets with reuseport option, the **struct bpf_sock**
   2231  *		result is from **reuse->socks**\ [] using the hash of the tuple.
   2232  *
   2233  * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
   2234  *	Description
   2235  *		Look for UDP socket matching *tuple*, optionally in a child
   2236  *		network namespace *netns*. The return value must be checked,
   2237  *		and if non-**NULL**, released via **bpf_sk_release**\ ().
   2238  *
   2239  *		The *ctx* should point to the context of the program, such as
   2240  *		the skb or socket (depending on the hook in use). This is used
   2241  *		to determine the base network namespace for the lookup.
   2242  *
   2243  *		*tuple_size* must be one of:
   2244  *
   2245  *		**sizeof**\ (*tuple*\ **->ipv4**)
   2246  *			Look for an IPv4 socket.
   2247  *		**sizeof**\ (*tuple*\ **->ipv6**)
   2248  *			Look for an IPv6 socket.
   2249  *
   2250  *		If the *netns* is a negative signed 32-bit integer, then the
   2251  *		socket lookup table in the netns associated with the *ctx* will
   2252  *		will be used. For the TC hooks, this is the netns of the device
   2253  *		in the skb. For socket hooks, this is the netns of the socket.
   2254  *		If *netns* is any other signed 32-bit value greater than or
   2255  *		equal to zero then it specifies the ID of the netns relative to
   2256  *		the netns associated with the *ctx*. *netns* values beyond the
   2257  *		range of 32-bit integers are reserved for future use.
   2258  *
   2259  *		All values for *flags* are reserved for future usage, and must
   2260  *		be left at zero.
   2261  *
   2262  *		This helper is available only if the kernel was compiled with
   2263  *		**CONFIG_NET** configuration option.
   2264  *	Return
   2265  *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
   2266  *		For sockets with reuseport option, the **struct bpf_sock**
   2267  *		result is from **reuse->socks**\ [] using the hash of the tuple.
   2268  *
   2269  * int bpf_sk_release(struct bpf_sock *sock)
   2270  *	Description
   2271  *		Release the reference held by *sock*. *sock* must be a
   2272  *		non-**NULL** pointer that was returned from
   2273  *		**bpf_sk_lookup_xxx**\ ().
   2274  *	Return
   2275  *		0 on success, or a negative error in case of failure.
   2276  *
   2277  * int bpf_map_pop_elem(struct bpf_map *map, void *value)
   2278  * 	Description
   2279  * 		Pop an element from *map*.
   2280  * 	Return
   2281  * 		0 on success, or a negative error in case of failure.
   2282  *
   2283  * int bpf_map_peek_elem(struct bpf_map *map, void *value)
   2284  * 	Description
   2285  * 		Get an element from *map* without removing it.
   2286  * 	Return
   2287  * 		0 on success, or a negative error in case of failure.
   2288  *
   2289  * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
   2290  *	Description
   2291  *		For socket policies, insert *len* bytes into *msg* at offset
   2292  *		*start*.
   2293  *
   2294  *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
   2295  *		*msg* it may want to insert metadata or options into the *msg*.
   2296  *		This can later be read and used by any of the lower layer BPF
   2297  *		hooks.
   2298  *
   2299  *		This helper may fail if under memory pressure (a malloc
   2300  *		fails) in these cases BPF programs will get an appropriate
   2301  *		error and BPF programs will need to handle them.
   2302  *	Return
   2303  *		0 on success, or a negative error in case of failure.
   2304  *
   2305  * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
   2306  *	Description
   2307  *		Will remove *pop* bytes from a *msg* starting at byte *start*.
   2308  *		This may result in **ENOMEM** errors under certain situations if
   2309  *		an allocation and copy are required due to a full ring buffer.
   2310  *		However, the helper will try to avoid doing the allocation
   2311  *		if possible. Other errors can occur if input parameters are
   2312  *		invalid either due to *start* byte not being valid part of *msg*
   2313  *		payload and/or *pop* value being to large.
   2314  *	Return
   2315  *		0 on success, or a negative error in case of failure.
   2316  *
   2317  * int bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
   2318  *	Description
   2319  *		This helper is used in programs implementing IR decoding, to
   2320  *		report a successfully decoded pointer movement.
   2321  *
   2322  *		The *ctx* should point to the lirc sample as passed into
   2323  *		the program.
   2324  *
   2325  *		This helper is only available is the kernel was compiled with
   2326  *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
   2327  *		"**y**".
   2328  *	Return
   2329  *		0
   2330  */
   2331 #define __BPF_FUNC_MAPPER(FN)		\
   2332 	FN(unspec),			\
   2333 	FN(map_lookup_elem),		\
   2334 	FN(map_update_elem),		\
   2335 	FN(map_delete_elem),		\
   2336 	FN(probe_read),			\
   2337 	FN(ktime_get_ns),		\
   2338 	FN(trace_printk),		\
   2339 	FN(get_prandom_u32),		\
   2340 	FN(get_smp_processor_id),	\
   2341 	FN(skb_store_bytes),		\
   2342 	FN(l3_csum_replace),		\
   2343 	FN(l4_csum_replace),		\
   2344 	FN(tail_call),			\
   2345 	FN(clone_redirect),		\
   2346 	FN(get_current_pid_tgid),	\
   2347 	FN(get_current_uid_gid),	\
   2348 	FN(get_current_comm),		\
   2349 	FN(get_cgroup_classid),		\
   2350 	FN(skb_vlan_push),		\
   2351 	FN(skb_vlan_pop),		\
   2352 	FN(skb_get_tunnel_key),		\
   2353 	FN(skb_set_tunnel_key),		\
   2354 	FN(perf_event_read),		\
   2355 	FN(redirect),			\
   2356 	FN(get_route_realm),		\
   2357 	FN(perf_event_output),		\
   2358 	FN(skb_load_bytes),		\
   2359 	FN(get_stackid),		\
   2360 	FN(csum_diff),			\
   2361 	FN(skb_get_tunnel_opt),		\
   2362 	FN(skb_set_tunnel_opt),		\
   2363 	FN(skb_change_proto),		\
   2364 	FN(skb_change_type),		\
   2365 	FN(skb_under_cgroup),		\
   2366 	FN(get_hash_recalc),		\
   2367 	FN(get_current_task),		\
   2368 	FN(probe_write_user),		\
   2369 	FN(current_task_under_cgroup),	\
   2370 	FN(skb_change_tail),		\
   2371 	FN(skb_pull_data),		\
   2372 	FN(csum_update),		\
   2373 	FN(set_hash_invalid),		\
   2374 	FN(get_numa_node_id),		\
   2375 	FN(skb_change_head),		\
   2376 	FN(xdp_adjust_head),		\
   2377 	FN(probe_read_str),		\
   2378 	FN(get_socket_cookie),		\
   2379 	FN(get_socket_uid),		\
   2380 	FN(set_hash),			\
   2381 	FN(setsockopt),			\
   2382 	FN(skb_adjust_room),		\
   2383 	FN(redirect_map),		\
   2384 	FN(sk_redirect_map),		\
   2385 	FN(sock_map_update),		\
   2386 	FN(xdp_adjust_meta),		\
   2387 	FN(perf_event_read_value),	\
   2388 	FN(perf_prog_read_value),	\
   2389 	FN(getsockopt),			\
   2390 	FN(override_return),		\
   2391 	FN(sock_ops_cb_flags_set),	\
   2392 	FN(msg_redirect_map),		\
   2393 	FN(msg_apply_bytes),		\
   2394 	FN(msg_cork_bytes),		\
   2395 	FN(msg_pull_data),		\
   2396 	FN(bind),			\
   2397 	FN(xdp_adjust_tail),		\
   2398 	FN(skb_get_xfrm_state),		\
   2399 	FN(get_stack),			\
   2400 	FN(skb_load_bytes_relative),	\
   2401 	FN(fib_lookup),			\
   2402 	FN(sock_hash_update),		\
   2403 	FN(msg_redirect_hash),		\
   2404 	FN(sk_redirect_hash),		\
   2405 	FN(lwt_push_encap),		\
   2406 	FN(lwt_seg6_store_bytes),	\
   2407 	FN(lwt_seg6_adjust_srh),	\
   2408 	FN(lwt_seg6_action),		\
   2409 	FN(rc_repeat),			\
   2410 	FN(rc_keydown),			\
   2411 	FN(skb_cgroup_id),		\
   2412 	FN(get_current_cgroup_id),	\
   2413 	FN(get_local_storage),		\
   2414 	FN(sk_select_reuseport),	\
   2415 	FN(skb_ancestor_cgroup_id),	\
   2416 	FN(sk_lookup_tcp),		\
   2417 	FN(sk_lookup_udp),		\
   2418 	FN(sk_release),			\
   2419 	FN(map_push_elem),		\
   2420 	FN(map_pop_elem),		\
   2421 	FN(map_peek_elem),		\
   2422 	FN(msg_push_data),		\
   2423 	FN(msg_pop_data),		\
   2424 	FN(rc_pointer_rel),
   2425 
   2426 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
   2427  * function eBPF program intends to call
   2428  */
   2429 #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
   2430 enum bpf_func_id {
   2431 	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
   2432 	__BPF_FUNC_MAX_ID,
   2433 };
   2434 #undef __BPF_ENUM_FN
   2435 
   2436 /* All flags used by eBPF helper functions, placed here. */
   2437 
   2438 /* BPF_FUNC_skb_store_bytes flags. */
   2439 #define BPF_F_RECOMPUTE_CSUM		(1ULL << 0)
   2440 #define BPF_F_INVALIDATE_HASH		(1ULL << 1)
   2441 
   2442 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
   2443  * First 4 bits are for passing the header field size.
   2444  */
   2445 #define BPF_F_HDR_FIELD_MASK		0xfULL
   2446 
   2447 /* BPF_FUNC_l4_csum_replace flags. */
   2448 #define BPF_F_PSEUDO_HDR		(1ULL << 4)
   2449 #define BPF_F_MARK_MANGLED_0		(1ULL << 5)
   2450 #define BPF_F_MARK_ENFORCE		(1ULL << 6)
   2451 
   2452 /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
   2453 #define BPF_F_INGRESS			(1ULL << 0)
   2454 
   2455 /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
   2456 #define BPF_F_TUNINFO_IPV6		(1ULL << 0)
   2457 
   2458 /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
   2459 #define BPF_F_SKIP_FIELD_MASK		0xffULL
   2460 #define BPF_F_USER_STACK		(1ULL << 8)
   2461 /* flags used by BPF_FUNC_get_stackid only. */
   2462 #define BPF_F_FAST_STACK_CMP		(1ULL << 9)
   2463 #define BPF_F_REUSE_STACKID		(1ULL << 10)
   2464 /* flags used by BPF_FUNC_get_stack only. */
   2465 #define BPF_F_USER_BUILD_ID		(1ULL << 11)
   2466 
   2467 /* BPF_FUNC_skb_set_tunnel_key flags. */
   2468 #define BPF_F_ZERO_CSUM_TX		(1ULL << 1)
   2469 #define BPF_F_DONT_FRAGMENT		(1ULL << 2)
   2470 #define BPF_F_SEQ_NUMBER		(1ULL << 3)
   2471 
   2472 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
   2473  * BPF_FUNC_perf_event_read_value flags.
   2474  */
   2475 #define BPF_F_INDEX_MASK		0xffffffffULL
   2476 #define BPF_F_CURRENT_CPU		BPF_F_INDEX_MASK
   2477 /* BPF_FUNC_perf_event_output for sk_buff input context. */
   2478 #define BPF_F_CTXLEN_MASK		(0xfffffULL << 32)
   2479 
   2480 /* Current network namespace */
   2481 #define BPF_F_CURRENT_NETNS		(-1L)
   2482 
   2483 /* Mode for BPF_FUNC_skb_adjust_room helper. */
   2484 enum bpf_adj_room_mode {
   2485 	BPF_ADJ_ROOM_NET,
   2486 };
   2487 
   2488 /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
   2489 enum bpf_hdr_start_off {
   2490 	BPF_HDR_START_MAC,
   2491 	BPF_HDR_START_NET,
   2492 };
   2493 
   2494 /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
   2495 enum bpf_lwt_encap_mode {
   2496 	BPF_LWT_ENCAP_SEG6,
   2497 	BPF_LWT_ENCAP_SEG6_INLINE
   2498 };
   2499 
   2500 #define __bpf_md_ptr(type, name)	\
   2501 union {					\
   2502 	type name;			\
   2503 	__u64 :64;			\
   2504 } __attribute__((aligned(8)))
   2505 
   2506 /* user accessible mirror of in-kernel sk_buff.
   2507  * new fields can only be added to the end of this structure
   2508  */
   2509 struct __sk_buff {
   2510 	__u32 len;
   2511 	__u32 pkt_type;
   2512 	__u32 mark;
   2513 	__u32 queue_mapping;
   2514 	__u32 protocol;
   2515 	__u32 vlan_present;
   2516 	__u32 vlan_tci;
   2517 	__u32 vlan_proto;
   2518 	__u32 priority;
   2519 	__u32 ingress_ifindex;
   2520 	__u32 ifindex;
   2521 	__u32 tc_index;
   2522 	__u32 cb[5];
   2523 	__u32 hash;
   2524 	__u32 tc_classid;
   2525 	__u32 data;
   2526 	__u32 data_end;
   2527 	__u32 napi_id;
   2528 
   2529 	/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
   2530 	__u32 family;
   2531 	__u32 remote_ip4;	/* Stored in network byte order */
   2532 	__u32 local_ip4;	/* Stored in network byte order */
   2533 	__u32 remote_ip6[4];	/* Stored in network byte order */
   2534 	__u32 local_ip6[4];	/* Stored in network byte order */
   2535 	__u32 remote_port;	/* Stored in network byte order */
   2536 	__u32 local_port;	/* stored in host byte order */
   2537 	/* ... here. */
   2538 
   2539 	__u32 data_meta;
   2540 	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
   2541 	__u64 tstamp;
   2542 	__u32 wire_len;
   2543 };
   2544 
   2545 struct bpf_tunnel_key {
   2546 	__u32 tunnel_id;
   2547 	union {
   2548 		__u32 remote_ipv4;
   2549 		__u32 remote_ipv6[4];
   2550 	};
   2551 	__u8 tunnel_tos;
   2552 	__u8 tunnel_ttl;
   2553 	__u16 tunnel_ext;	/* Padding, future use. */
   2554 	__u32 tunnel_label;
   2555 };
   2556 
   2557 /* user accessible mirror of in-kernel xfrm_state.
   2558  * new fields can only be added to the end of this structure
   2559  */
   2560 struct bpf_xfrm_state {
   2561 	__u32 reqid;
   2562 	__u32 spi;	/* Stored in network byte order */
   2563 	__u16 family;
   2564 	__u16 ext;	/* Padding, future use. */
   2565 	union {
   2566 		__u32 remote_ipv4;	/* Stored in network byte order */
   2567 		__u32 remote_ipv6[4];	/* Stored in network byte order */
   2568 	};
   2569 };
   2570 
   2571 /* Generic BPF return codes which all BPF program types may support.
   2572  * The values are binary compatible with their TC_ACT_* counter-part to
   2573  * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
   2574  * programs.
   2575  *
   2576  * XDP is handled seprately, see XDP_*.
   2577  */
   2578 enum bpf_ret_code {
   2579 	BPF_OK = 0,
   2580 	/* 1 reserved */
   2581 	BPF_DROP = 2,
   2582 	/* 3-6 reserved */
   2583 	BPF_REDIRECT = 7,
   2584 	/* >127 are reserved for prog type specific return codes */
   2585 };
   2586 
   2587 struct bpf_sock {
   2588 	__u32 bound_dev_if;
   2589 	__u32 family;
   2590 	__u32 type;
   2591 	__u32 protocol;
   2592 	__u32 mark;
   2593 	__u32 priority;
   2594 	__u32 src_ip4;		/* Allows 1,2,4-byte read.
   2595 				 * Stored in network byte order.
   2596 				 */
   2597 	__u32 src_ip6[4];	/* Allows 1,2,4-byte read.
   2598 				 * Stored in network byte order.
   2599 				 */
   2600 	__u32 src_port;		/* Allows 4-byte read.
   2601 				 * Stored in host byte order
   2602 				 */
   2603 };
   2604 
   2605 struct bpf_sock_tuple {
   2606 	union {
   2607 		struct {
   2608 			__be32 saddr;
   2609 			__be32 daddr;
   2610 			__be16 sport;
   2611 			__be16 dport;
   2612 		} ipv4;
   2613 		struct {
   2614 			__be32 saddr[4];
   2615 			__be32 daddr[4];
   2616 			__be16 sport;
   2617 			__be16 dport;
   2618 		} ipv6;
   2619 	};
   2620 };
   2621 
   2622 #define XDP_PACKET_HEADROOM 256
   2623 
   2624 /* User return codes for XDP prog type.
   2625  * A valid XDP program must return one of these defined values. All other
   2626  * return codes are reserved for future use. Unknown return codes will
   2627  * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
   2628  */
   2629 enum xdp_action {
   2630 	XDP_ABORTED = 0,
   2631 	XDP_DROP,
   2632 	XDP_PASS,
   2633 	XDP_TX,
   2634 	XDP_REDIRECT,
   2635 };
   2636 
   2637 /* user accessible metadata for XDP packet hook
   2638  * new fields must be added to the end of this structure
   2639  */
   2640 struct xdp_md {
   2641 	__u32 data;
   2642 	__u32 data_end;
   2643 	__u32 data_meta;
   2644 	/* Below access go through struct xdp_rxq_info */
   2645 	__u32 ingress_ifindex; /* rxq->dev->ifindex */
   2646 	__u32 rx_queue_index;  /* rxq->queue_index  */
   2647 };
   2648 
   2649 enum sk_action {
   2650 	SK_DROP = 0,
   2651 	SK_PASS,
   2652 };
   2653 
   2654 /* user accessible metadata for SK_MSG packet hook, new fields must
   2655  * be added to the end of this structure
   2656  */
   2657 struct sk_msg_md {
   2658 	__bpf_md_ptr(void *, data);
   2659 	__bpf_md_ptr(void *, data_end);
   2660 
   2661 	__u32 family;
   2662 	__u32 remote_ip4;	/* Stored in network byte order */
   2663 	__u32 local_ip4;	/* Stored in network byte order */
   2664 	__u32 remote_ip6[4];	/* Stored in network byte order */
   2665 	__u32 local_ip6[4];	/* Stored in network byte order */
   2666 	__u32 remote_port;	/* Stored in network byte order */
   2667 	__u32 local_port;	/* stored in host byte order */
   2668 	__u32 size;		/* Total size of sk_msg */
   2669 };
   2670 
   2671 struct sk_reuseport_md {
   2672 	/*
   2673 	 * Start of directly accessible data. It begins from
   2674 	 * the tcp/udp header.
   2675 	 */
   2676 	__bpf_md_ptr(void *, data);
   2677 	/* End of directly accessible data */
   2678 	__bpf_md_ptr(void *, data_end);
   2679 	/*
   2680 	 * Total length of packet (starting from the tcp/udp header).
   2681 	 * Note that the directly accessible bytes (data_end - data)
   2682 	 * could be less than this "len".  Those bytes could be
   2683 	 * indirectly read by a helper "bpf_skb_load_bytes()".
   2684 	 */
   2685 	__u32 len;
   2686 	/*
   2687 	 * Eth protocol in the mac header (network byte order). e.g.
   2688 	 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
   2689 	 */
   2690 	__u32 eth_protocol;
   2691 	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
   2692 	__u32 bind_inany;	/* Is sock bound to an INANY address? */
   2693 	__u32 hash;		/* A hash of the packet 4 tuples */
   2694 };
   2695 
   2696 #define BPF_TAG_SIZE	8
   2697 
   2698 struct bpf_prog_info {
   2699 	__u32 type;
   2700 	__u32 id;
   2701 	__u8  tag[BPF_TAG_SIZE];
   2702 	__u32 jited_prog_len;
   2703 	__u32 xlated_prog_len;
   2704 	__aligned_u64 jited_prog_insns;
   2705 	__aligned_u64 xlated_prog_insns;
   2706 	__u64 load_time;	/* ns since boottime */
   2707 	__u32 created_by_uid;
   2708 	__u32 nr_map_ids;
   2709 	__aligned_u64 map_ids;
   2710 	char name[BPF_OBJ_NAME_LEN];
   2711 	__u32 ifindex;
   2712 	__u32 gpl_compatible:1;
   2713 	__u64 netns_dev;
   2714 	__u64 netns_ino;
   2715 	__u32 nr_jited_ksyms;
   2716 	__u32 nr_jited_func_lens;
   2717 	__aligned_u64 jited_ksyms;
   2718 	__aligned_u64 jited_func_lens;
   2719 	__u32 btf_id;
   2720 	__u32 func_info_rec_size;
   2721 	__aligned_u64 func_info;
   2722 	__u32 nr_func_info;
   2723 	__u32 nr_line_info;
   2724 	__aligned_u64 line_info;
   2725 	__aligned_u64 jited_line_info;
   2726 	__u32 nr_jited_line_info;
   2727 	__u32 line_info_rec_size;
   2728 	__u32 jited_line_info_rec_size;
   2729 	__u32 nr_prog_tags;
   2730 	__aligned_u64 prog_tags;
   2731 } __attribute__((aligned(8)));
   2732 
   2733 struct bpf_map_info {
   2734 	__u32 type;
   2735 	__u32 id;
   2736 	__u32 key_size;
   2737 	__u32 value_size;
   2738 	__u32 max_entries;
   2739 	__u32 map_flags;
   2740 	char  name[BPF_OBJ_NAME_LEN];
   2741 	__u32 ifindex;
   2742 	__u32 :32;
   2743 	__u64 netns_dev;
   2744 	__u64 netns_ino;
   2745 	__u32 btf_id;
   2746 	__u32 btf_key_type_id;
   2747 	__u32 btf_value_type_id;
   2748 } __attribute__((aligned(8)));
   2749 
   2750 struct bpf_btf_info {
   2751 	__aligned_u64 btf;
   2752 	__u32 btf_size;
   2753 	__u32 id;
   2754 } __attribute__((aligned(8)));
   2755 
   2756 /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
   2757  * by user and intended to be used by socket (e.g. to bind to, depends on
   2758  * attach attach type).
   2759  */
   2760 struct bpf_sock_addr {
   2761 	__u32 user_family;	/* Allows 4-byte read, but no write. */
   2762 	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.
   2763 				 * Stored in network byte order.
   2764 				 */
   2765 	__u32 user_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
   2766 				 * Stored in network byte order.
   2767 				 */
   2768 	__u32 user_port;	/* Allows 4-byte read and write.
   2769 				 * Stored in network byte order
   2770 				 */
   2771 	__u32 family;		/* Allows 4-byte read, but no write */
   2772 	__u32 type;		/* Allows 4-byte read, but no write */
   2773 	__u32 protocol;		/* Allows 4-byte read, but no write */
   2774 	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read an 4-byte write.
   2775 				 * Stored in network byte order.
   2776 				 */
   2777 	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
   2778 				 * Stored in network byte order.
   2779 				 */
   2780 };
   2781 
   2782 /* User bpf_sock_ops struct to access socket values and specify request ops
   2783  * and their replies.
   2784  * Some of this fields are in network (bigendian) byte order and may need
   2785  * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
   2786  * New fields can only be added at the end of this structure
   2787  */
   2788 struct bpf_sock_ops {
   2789 	__u32 op;
   2790 	union {
   2791 		__u32 args[4];		/* Optionally passed to bpf program */
   2792 		__u32 reply;		/* Returned by bpf program	    */
   2793 		__u32 replylong[4];	/* Optionally returned by bpf prog  */
   2794 	};
   2795 	__u32 family;
   2796 	__u32 remote_ip4;	/* Stored in network byte order */
   2797 	__u32 local_ip4;	/* Stored in network byte order */
   2798 	__u32 remote_ip6[4];	/* Stored in network byte order */
   2799 	__u32 local_ip6[4];	/* Stored in network byte order */
   2800 	__u32 remote_port;	/* Stored in network byte order */
   2801 	__u32 local_port;	/* stored in host byte order */
   2802 	__u32 is_fullsock;	/* Some TCP fields are only valid if
   2803 				 * there is a full socket. If not, the
   2804 				 * fields read as zero.
   2805 				 */
   2806 	__u32 snd_cwnd;
   2807 	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
   2808 	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
   2809 	__u32 state;
   2810 	__u32 rtt_min;
   2811 	__u32 snd_ssthresh;
   2812 	__u32 rcv_nxt;
   2813 	__u32 snd_nxt;
   2814 	__u32 snd_una;
   2815 	__u32 mss_cache;
   2816 	__u32 ecn_flags;
   2817 	__u32 rate_delivered;
   2818 	__u32 rate_interval_us;
   2819 	__u32 packets_out;
   2820 	__u32 retrans_out;
   2821 	__u32 total_retrans;
   2822 	__u32 segs_in;
   2823 	__u32 data_segs_in;
   2824 	__u32 segs_out;
   2825 	__u32 data_segs_out;
   2826 	__u32 lost_out;
   2827 	__u32 sacked_out;
   2828 	__u32 sk_txhash;
   2829 	__u64 bytes_received;
   2830 	__u64 bytes_acked;
   2831 };
   2832 
   2833 /* Definitions for bpf_sock_ops_cb_flags */
   2834 #define BPF_SOCK_OPS_RTO_CB_FLAG	(1<<0)
   2835 #define BPF_SOCK_OPS_RETRANS_CB_FLAG	(1<<1)
   2836 #define BPF_SOCK_OPS_STATE_CB_FLAG	(1<<2)
   2837 #define BPF_SOCK_OPS_ALL_CB_FLAGS       0x7		/* Mask of all currently
   2838 							 * supported cb flags
   2839 							 */
   2840 
   2841 /* List of known BPF sock_ops operators.
   2842  * New entries can only be added at the end
   2843  */
   2844 enum {
   2845 	BPF_SOCK_OPS_VOID,
   2846 	BPF_SOCK_OPS_TIMEOUT_INIT,	/* Should return SYN-RTO value to use or
   2847 					 * -1 if default value should be used
   2848 					 */
   2849 	BPF_SOCK_OPS_RWND_INIT,		/* Should return initial advertized
   2850 					 * window (in packets) or -1 if default
   2851 					 * value should be used
   2852 					 */
   2853 	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
   2854 					 * active connection is initialized
   2855 					 */
   2856 	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
   2857 						 * active connection is
   2858 						 * established
   2859 						 */
   2860 	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
   2861 						 * passive connection is
   2862 						 * established
   2863 						 */
   2864 	BPF_SOCK_OPS_NEEDS_ECN,		/* If connection's congestion control
   2865 					 * needs ECN
   2866 					 */
   2867 	BPF_SOCK_OPS_BASE_RTT,		/* Get base RTT. The correct value is
   2868 					 * based on the path and may be
   2869 					 * dependent on the congestion control
   2870 					 * algorithm. In general it indicates
   2871 					 * a congestion threshold. RTTs above
   2872 					 * this indicate congestion
   2873 					 */
   2874 	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
   2875 					 * Arg1: value of icsk_retransmits
   2876 					 * Arg2: value of icsk_rto
   2877 					 * Arg3: whether RTO has expired
   2878 					 */
   2879 	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
   2880 					 * Arg1: sequence number of 1st byte
   2881 					 * Arg2: # segments
   2882 					 * Arg3: return value of
   2883 					 *       tcp_transmit_skb (0 => success)
   2884 					 */
   2885 	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
   2886 					 * Arg1: old_state
   2887 					 * Arg2: new_state
   2888 					 */
   2889 	BPF_SOCK_OPS_TCP_LISTEN_CB,	/* Called on listen(2), right after
   2890 					 * socket transition to LISTEN state.
   2891 					 */
   2892 };
   2893 
   2894 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
   2895  * changes between the TCP and BPF versions. Ideally this should never happen.
   2896  * If it does, we need to add code to convert them before calling
   2897  * the BPF sock_ops function.
   2898  */
   2899 enum {
   2900 	BPF_TCP_ESTABLISHED = 1,
   2901 	BPF_TCP_SYN_SENT,
   2902 	BPF_TCP_SYN_RECV,
   2903 	BPF_TCP_FIN_WAIT1,
   2904 	BPF_TCP_FIN_WAIT2,
   2905 	BPF_TCP_TIME_WAIT,
   2906 	BPF_TCP_CLOSE,
   2907 	BPF_TCP_CLOSE_WAIT,
   2908 	BPF_TCP_LAST_ACK,
   2909 	BPF_TCP_LISTEN,
   2910 	BPF_TCP_CLOSING,	/* Now a valid state */
   2911 	BPF_TCP_NEW_SYN_RECV,
   2912 
   2913 	BPF_TCP_MAX_STATES	/* Leave at the end! */
   2914 };
   2915 
   2916 #define TCP_BPF_IW		1001	/* Set TCP initial congestion window */
   2917 #define TCP_BPF_SNDCWND_CLAMP	1002	/* Set sndcwnd_clamp */
   2918 
   2919 struct bpf_perf_event_value {
   2920 	__u64 counter;
   2921 	__u64 enabled;
   2922 	__u64 running;
   2923 };
   2924 
   2925 #define BPF_DEVCG_ACC_MKNOD	(1ULL << 0)
   2926 #define BPF_DEVCG_ACC_READ	(1ULL << 1)
   2927 #define BPF_DEVCG_ACC_WRITE	(1ULL << 2)
   2928 
   2929 #define BPF_DEVCG_DEV_BLOCK	(1ULL << 0)
   2930 #define BPF_DEVCG_DEV_CHAR	(1ULL << 1)
   2931 
   2932 struct bpf_cgroup_dev_ctx {
   2933 	/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
   2934 	__u32 access_type;
   2935 	__u32 major;
   2936 	__u32 minor;
   2937 };
   2938 
   2939 struct bpf_raw_tracepoint_args {
   2940 	__u64 args[0];
   2941 };
   2942 
   2943 /* DIRECT:  Skip the FIB rules and go to FIB table associated with device
   2944  * OUTPUT:  Do lookup from egress perspective; default is ingress
   2945  */
   2946 #define BPF_FIB_LOOKUP_DIRECT  BIT(0)
   2947 #define BPF_FIB_LOOKUP_OUTPUT  BIT(1)
   2948 
   2949 enum {
   2950 	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
   2951 	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
   2952 	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
   2953 	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
   2954 	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
   2955 	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
   2956 	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
   2957 	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
   2958 	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
   2959 };
   2960 
   2961 struct bpf_fib_lookup {
   2962 	/* input:  network family for lookup (AF_INET, AF_INET6)
   2963 	 * output: network family of egress nexthop
   2964 	 */
   2965 	__u8	family;
   2966 
   2967 	/* set if lookup is to consider L4 data - e.g., FIB rules */
   2968 	__u8	l4_protocol;
   2969 	__be16	sport;
   2970 	__be16	dport;
   2971 
   2972 	/* total length of packet from network header - used for MTU check */
   2973 	__u16	tot_len;
   2974 
   2975 	/* input: L3 device index for lookup
   2976 	 * output: device index from FIB lookup
   2977 	 */
   2978 	__u32	ifindex;
   2979 
   2980 	union {
   2981 		/* inputs to lookup */
   2982 		__u8	tos;		/* AF_INET  */
   2983 		__be32	flowinfo;	/* AF_INET6, flow_label + priority */
   2984 
   2985 		/* output: metric of fib result (IPv4/IPv6 only) */
   2986 		__u32	rt_metric;
   2987 	};
   2988 
   2989 	union {
   2990 		__be32		ipv4_src;
   2991 		__u32		ipv6_src[4];  /* in6_addr; network order */
   2992 	};
   2993 
   2994 	/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
   2995 	 * network header. output: bpf_fib_lookup sets to gateway address
   2996 	 * if FIB lookup returns gateway route
   2997 	 */
   2998 	union {
   2999 		__be32		ipv4_dst;
   3000 		__u32		ipv6_dst[4];  /* in6_addr; network order */
   3001 	};
   3002 
   3003 	/* output */
   3004 	__be16	h_vlan_proto;
   3005 	__be16	h_vlan_TCI;
   3006 	__u8	smac[6];     /* ETH_ALEN */
   3007 	__u8	dmac[6];     /* ETH_ALEN */
   3008 };
   3009 
   3010 enum bpf_task_fd_type {
   3011 	BPF_FD_TYPE_RAW_TRACEPOINT,	/* tp name */
   3012 	BPF_FD_TYPE_TRACEPOINT,		/* tp name */
   3013 	BPF_FD_TYPE_KPROBE,		/* (symbol + offset) or addr */
   3014 	BPF_FD_TYPE_KRETPROBE,		/* (symbol + offset) or addr */
   3015 	BPF_FD_TYPE_UPROBE,		/* filename + offset */
   3016 	BPF_FD_TYPE_URETPROBE,		/* filename + offset */
   3017 };
   3018 
   3019 struct bpf_flow_keys {
   3020 	__u16	nhoff;
   3021 	__u16	thoff;
   3022 	__u16	addr_proto;			/* ETH_P_* of valid addrs */
   3023 	__u8	is_frag;
   3024 	__u8	is_first_frag;
   3025 	__u8	is_encap;
   3026 	__u8	ip_proto;
   3027 	__be16	n_proto;
   3028 	__be16	sport;
   3029 	__be16	dport;
   3030 	union {
   3031 		struct {
   3032 			__be32	ipv4_src;
   3033 			__be32	ipv4_dst;
   3034 		};
   3035 		struct {
   3036 			__u32	ipv6_src[4];	/* in6_addr; network order */
   3037 			__u32	ipv6_dst[4];	/* in6_addr; network order */
   3038 		};
   3039 	};
   3040 };
   3041 
   3042 struct bpf_func_info {
   3043 	__u32	insn_off;
   3044 	__u32	type_id;
   3045 };
   3046 
   3047 #define BPF_LINE_INFO_LINE_NUM(line_col)	((line_col) >> 10)
   3048 #define BPF_LINE_INFO_LINE_COL(line_col)	((line_col) & 0x3ff)
   3049 
   3050 struct bpf_line_info {
   3051 	__u32	insn_off;
   3052 	__u32	file_name_off;
   3053 	__u32	line_off;
   3054 	__u32	line_col;
   3055 };
   3056 
   3057 #endif /* _UAPI__LINUX_BPF_H__ */
   3058