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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#ifndef __LINUX_BPF_H__
#define __LINUX_BPF_H__
#include <linux/types.h>
#include <linux/bpf_common.h>
/* Extended instruction set based on top of classic BPF */
/* instruction classes */
#define BPF_JMP32 0x06 /* jmp mode in word width */
#define BPF_ALU64 0x07 /* alu mode in double word width */
/* ld/ldx fields */
#define BPF_DW 0x18 /* double word (64-bit) */
#define BPF_XADD 0xc0 /* exclusive add */
/* alu/jmp fields */
#define BPF_MOV 0xb0 /* mov reg to reg */
#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
/* change endianness of a register */
#define BPF_END 0xd0 /* flags for endianness conversion: */
#define BPF_TO_LE 0x00 /* convert to little-endian */
#define BPF_TO_BE 0x08 /* convert to big-endian */
#define BPF_FROM_LE BPF_TO_LE
#define BPF_FROM_BE BPF_TO_BE
/* jmp encodings */
#define BPF_JNE 0x50 /* jump != */
#define BPF_JLT 0xa0 /* LT is unsigned, '<' */
#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
#define BPF_JSLT 0xc0 /* SLT is signed, '<' */
#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
#define BPF_CALL 0x80 /* function call */
#define BPF_EXIT 0x90 /* function return */
/* Register numbers */
enum {
BPF_REG_0 = 0,
BPF_REG_1,
BPF_REG_2,
BPF_REG_3,
BPF_REG_4,
BPF_REG_5,
BPF_REG_6,
BPF_REG_7,
BPF_REG_8,
BPF_REG_9,
BPF_REG_10,
__MAX_BPF_REG,
};
/* BPF has 10 general purpose 64-bit registers and stack frame. */
#define MAX_BPF_REG __MAX_BPF_REG
struct bpf_insn {
__u8 code; /* opcode */
__u8 dst_reg:4; /* dest register */
__u8 src_reg:4; /* source register */
__s16 off; /* signed offset */
__s32 imm; /* signed immediate constant */
};
/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
struct bpf_lpm_trie_key {
__u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
__u8 data[0]; /* Arbitrary size */
};
struct bpf_cgroup_storage_key {
__u64 cgroup_inode_id; /* cgroup inode id */
__u32 attach_type; /* program attach type */
};
/* BPF syscall commands, see bpf(2) man-page for details. */
enum bpf_cmd {
BPF_MAP_CREATE,
BPF_MAP_LOOKUP_ELEM,
BPF_MAP_UPDATE_ELEM,
BPF_MAP_DELETE_ELEM,
BPF_MAP_GET_NEXT_KEY,
BPF_PROG_LOAD,
BPF_OBJ_PIN,
BPF_OBJ_GET,
BPF_PROG_ATTACH,
BPF_PROG_DETACH,
BPF_PROG_TEST_RUN,
BPF_PROG_GET_NEXT_ID,
BPF_MAP_GET_NEXT_ID,
BPF_PROG_GET_FD_BY_ID,
BPF_MAP_GET_FD_BY_ID,
BPF_OBJ_GET_INFO_BY_FD,
BPF_PROG_QUERY,
BPF_RAW_TRACEPOINT_OPEN,
BPF_BTF_LOAD,
BPF_BTF_GET_FD_BY_ID,
BPF_TASK_FD_QUERY,
BPF_MAP_LOOKUP_AND_DELETE_ELEM,
BPF_MAP_FREEZE,
BPF_BTF_GET_NEXT_ID,
};
enum bpf_map_type {
BPF_MAP_TYPE_UNSPEC,
BPF_MAP_TYPE_HASH,
BPF_MAP_TYPE_ARRAY,
BPF_MAP_TYPE_PROG_ARRAY,
BPF_MAP_TYPE_PERF_EVENT_ARRAY,
BPF_MAP_TYPE_PERCPU_HASH,
BPF_MAP_TYPE_PERCPU_ARRAY,
BPF_MAP_TYPE_STACK_TRACE,
BPF_MAP_TYPE_CGROUP_ARRAY,
BPF_MAP_TYPE_LRU_HASH,
BPF_MAP_TYPE_LRU_PERCPU_HASH,
BPF_MAP_TYPE_LPM_TRIE,
BPF_MAP_TYPE_ARRAY_OF_MAPS,
BPF_MAP_TYPE_HASH_OF_MAPS,
BPF_MAP_TYPE_DEVMAP,
BPF_MAP_TYPE_SOCKMAP,
BPF_MAP_TYPE_CPUMAP,
BPF_MAP_TYPE_XSKMAP,
BPF_MAP_TYPE_SOCKHASH,
BPF_MAP_TYPE_CGROUP_STORAGE,
BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
BPF_MAP_TYPE_QUEUE,
BPF_MAP_TYPE_STACK,
BPF_MAP_TYPE_SK_STORAGE,
BPF_MAP_TYPE_DEVMAP_HASH,
};
/* Note that tracing related programs such as
* BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
* are not subject to a stable API since kernel internal data
* structures can change from release to release and may
* therefore break existing tracing BPF programs. Tracing BPF
* programs correspond to /a/ specific kernel which is to be
* analyzed, and not /a/ specific kernel /and/ all future ones.
*/
enum bpf_prog_type {
BPF_PROG_TYPE_UNSPEC,
BPF_PROG_TYPE_SOCKET_FILTER,
BPF_PROG_TYPE_KPROBE,
BPF_PROG_TYPE_SCHED_CLS,
BPF_PROG_TYPE_SCHED_ACT,
BPF_PROG_TYPE_TRACEPOINT,
BPF_PROG_TYPE_XDP,
BPF_PROG_TYPE_PERF_EVENT,
BPF_PROG_TYPE_CGROUP_SKB,
BPF_PROG_TYPE_CGROUP_SOCK,
BPF_PROG_TYPE_LWT_IN,
BPF_PROG_TYPE_LWT_OUT,
BPF_PROG_TYPE_LWT_XMIT,
BPF_PROG_TYPE_SOCK_OPS,
BPF_PROG_TYPE_SK_SKB,
BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_PROG_TYPE_SK_MSG,
BPF_PROG_TYPE_RAW_TRACEPOINT,
BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_PROG_TYPE_LWT_SEG6LOCAL,
BPF_PROG_TYPE_LIRC_MODE2,
BPF_PROG_TYPE_SK_REUSEPORT,
BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
BPF_PROG_TYPE_CGROUP_SOCKOPT,
};
enum bpf_attach_type {
BPF_CGROUP_INET_INGRESS,
BPF_CGROUP_INET_EGRESS,
BPF_CGROUP_INET_SOCK_CREATE,
BPF_CGROUP_SOCK_OPS,
BPF_SK_SKB_STREAM_PARSER,
BPF_SK_SKB_STREAM_VERDICT,
BPF_CGROUP_DEVICE,
BPF_SK_MSG_VERDICT,
BPF_CGROUP_INET4_BIND,
BPF_CGROUP_INET6_BIND,
BPF_CGROUP_INET4_CONNECT,
BPF_CGROUP_INET6_CONNECT,
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_UDP4_SENDMSG,
BPF_CGROUP_UDP6_SENDMSG,
BPF_LIRC_MODE2,
BPF_FLOW_DISSECTOR,
BPF_CGROUP_SYSCTL,
BPF_CGROUP_UDP4_RECVMSG,
BPF_CGROUP_UDP6_RECVMSG,
BPF_CGROUP_GETSOCKOPT,
BPF_CGROUP_SETSOCKOPT,
__MAX_BPF_ATTACH_TYPE
};
#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
*
* NONE(default): No further bpf programs allowed in the subtree.
*
* BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
* the program in this cgroup yields to sub-cgroup program.
*
* BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
* that cgroup program gets run in addition to the program in this cgroup.
*
* Only one program is allowed to be attached to a cgroup with
* NONE or BPF_F_ALLOW_OVERRIDE flag.
* Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
* release old program and attach the new one. Attach flags has to match.
*
* Multiple programs are allowed to be attached to a cgroup with
* BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
* (those that were attached first, run first)
* The programs of sub-cgroup are executed first, then programs of
* this cgroup and then programs of parent cgroup.
* When children program makes decision (like picking TCP CA or sock bind)
* parent program has a chance to override it.
*
* A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
* A cgroup with NONE doesn't allow any programs in sub-cgroups.
* Ex1:
* cgrp1 (MULTI progs A, B) ->
* cgrp2 (OVERRIDE prog C) ->
* cgrp3 (MULTI prog D) ->
* cgrp4 (OVERRIDE prog E) ->
* cgrp5 (NONE prog F)
* the event in cgrp5 triggers execution of F,D,A,B in that order.
* if prog F is detached, the execution is E,D,A,B
* if prog F and D are detached, the execution is E,A,B
* if prog F, E and D are detached, the execution is C,A,B
*
* All eligible programs are executed regardless of return code from
* earlier programs.
*/
#define BPF_F_ALLOW_OVERRIDE (1U << 0)
#define BPF_F_ALLOW_MULTI (1U << 1)
/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
* verifier will perform strict alignment checking as if the kernel
* has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
* and NET_IP_ALIGN defined to 2.
*/
#define BPF_F_STRICT_ALIGNMENT (1U << 0)
/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
* verifier will allow any alignment whatsoever. On platforms
* with strict alignment requirements for loads ands stores (such
* as sparc and mips) the verifier validates that all loads and
* stores provably follow this requirement. This flag turns that
* checking and enforcement off.
*
* It is mostly used for testing when we want to validate the
* context and memory access aspects of the verifier, but because
* of an unaligned access the alignment check would trigger before
* the one we are interested in.
*/
#define BPF_F_ANY_ALIGNMENT (1U << 1)
/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
* Verifier does sub-register def/use analysis and identifies instructions whose
* def only matters for low 32-bit, high 32-bit is never referenced later
* through implicit zero extension. Therefore verifier notifies JIT back-ends
* that it is safe to ignore clearing high 32-bit for these instructions. This
* saves some back-ends a lot of code-gen. However such optimization is not
* necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
* hence hasn't used verifier's analysis result. But, we really want to have a
* way to be able to verify the correctness of the described optimization on
* x86_64 on which testsuites are frequently exercised.
*
* So, this flag is introduced. Once it is set, verifier will randomize high
* 32-bit for those instructions who has been identified as safe to ignore them.
* Then, if verifier is not doing correct analysis, such randomization will
* regress tests to expose bugs.
*/
#define BPF_F_TEST_RND_HI32 (1U << 2)
/* The verifier internal test flag. Behavior is undefined */
#define BPF_F_TEST_STATE_FREQ (1U << 3)
/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
* two extensions:
*
* insn[0].src_reg: BPF_PSEUDO_MAP_FD BPF_PSEUDO_MAP_VALUE
* insn[0].imm: map fd map fd
* insn[1].imm: 0 offset into value
* insn[0].off: 0 0
* insn[1].off: 0 0
* ldimm64 rewrite: address of map address of map[0]+offset
* verifier type: CONST_PTR_TO_MAP PTR_TO_MAP_VALUE
*/
#define BPF_PSEUDO_MAP_FD 1
#define BPF_PSEUDO_MAP_VALUE 2
/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
* offset to another bpf function
*/
#define BPF_PSEUDO_CALL 1
/* flags for BPF_MAP_UPDATE_ELEM command */
#define BPF_ANY 0 /* create new element or update existing */
#define BPF_NOEXIST 1 /* create new element if it didn't exist */
#define BPF_EXIST 2 /* update existing element */
#define BPF_F_LOCK 4 /* spin_lock-ed map_lookup/map_update */
/* flags for BPF_MAP_CREATE command */
#define BPF_F_NO_PREALLOC (1U << 0)
/* Instead of having one common LRU list in the
* BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
* which can scale and perform better.
* Note, the LRU nodes (including free nodes) cannot be moved
* across different LRU lists.
*/
#define BPF_F_NO_COMMON_LRU (1U << 1)
/* Specify numa node during map creation */
#define BPF_F_NUMA_NODE (1U << 2)
#define BPF_OBJ_NAME_LEN 16U
/* Flags for accessing BPF object from syscall side. */
#define BPF_F_RDONLY (1U << 3)
#define BPF_F_WRONLY (1U << 4)
/* Flag for stack_map, store build_id+offset instead of pointer */
#define BPF_F_STACK_BUILD_ID (1U << 5)
/* Zero-initialize hash function seed. This should only be used for testing. */
#define BPF_F_ZERO_SEED (1U << 6)
/* Flags for accessing BPF object from program side. */
#define BPF_F_RDONLY_PROG (1U << 7)
#define BPF_F_WRONLY_PROG (1U << 8)
/* Clone map from listener for newly accepted socket */
#define BPF_F_CLONE (1U << 9)
/* flags for BPF_PROG_QUERY */
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
enum bpf_stack_build_id_status {
/* user space need an empty entry to identify end of a trace */
BPF_STACK_BUILD_ID_EMPTY = 0,
/* with valid build_id and offset */
BPF_STACK_BUILD_ID_VALID = 1,
/* couldn't get build_id, fallback to ip */
BPF_STACK_BUILD_ID_IP = 2,
};
#define BPF_BUILD_ID_SIZE 20
struct bpf_stack_build_id {
__s32 status;
unsigned char build_id[BPF_BUILD_ID_SIZE];
union {
__u64 offset;
__u64 ip;
};
};
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */
__u32 key_size; /* size of key in bytes */
__u32 value_size; /* size of value in bytes */
__u32 max_entries; /* max number of entries in a map */
__u32 map_flags; /* BPF_MAP_CREATE related
* flags defined above.
*/
__u32 inner_map_fd; /* fd pointing to the inner map */
__u32 numa_node; /* numa node (effective only if
* BPF_F_NUMA_NODE is set).
*/
char map_name[BPF_OBJ_NAME_LEN];
__u32 map_ifindex; /* ifindex of netdev to create on */
__u32 btf_fd; /* fd pointing to a BTF type data */
__u32 btf_key_type_id; /* BTF type_id of the key */
__u32 btf_value_type_id; /* BTF type_id of the value */
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
__u32 map_fd;
__aligned_u64 key;
union {
__aligned_u64 value;
__aligned_u64 next_key;
};
__u64 flags;
};
struct { /* anonymous struct used by BPF_PROG_LOAD command */
__u32 prog_type; /* one of enum bpf_prog_type */
__u32 insn_cnt;
__aligned_u64 insns;
__aligned_u64 license;
__u32 log_level; /* verbosity level of verifier */
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied buffer */
__u32 kern_version; /* not used */
__u32 prog_flags;
char prog_name[BPF_OBJ_NAME_LEN];
__u32 prog_ifindex; /* ifindex of netdev to prep for */
/* For some prog types expected attach type must be known at
* load time to verify attach type specific parts of prog
* (context accesses, allowed helpers, etc).
*/
__u32 expected_attach_type;
__u32 prog_btf_fd; /* fd pointing to BTF type data */
__u32 func_info_rec_size; /* userspace bpf_func_info size */
__aligned_u64 func_info; /* func info */
__u32 func_info_cnt; /* number of bpf_func_info records */
__u32 line_info_rec_size; /* userspace bpf_line_info size */
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
__aligned_u64 pathname;
__u32 bpf_fd;
__u32 file_flags;
};
struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
__u32 target_fd; /* container object to attach to */
__u32 attach_bpf_fd; /* eBPF program to attach */
__u32 attach_type;
__u32 attach_flags;
};
struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
__u32 prog_fd;
__u32 retval;
__u32 data_size_in; /* input: len of data_in */
__u32 data_size_out; /* input/output: len of data_out
* returns ENOSPC if data_out
* is too small.
*/
__aligned_u64 data_in;
__aligned_u64 data_out;
__u32 repeat;
__u32 duration;
__u32 ctx_size_in; /* input: len of ctx_in */
__u32 ctx_size_out; /* input/output: len of ctx_out
* returns ENOSPC if ctx_out
* is too small.
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */
union {
__u32 start_id;
__u32 prog_id;
__u32 map_id;
__u32 btf_id;
};
__u32 next_id;
__u32 open_flags;
};
struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
__u32 bpf_fd;
__u32 info_len;
__aligned_u64 info;
} info;
struct { /* anonymous struct used by BPF_PROG_QUERY command */
__u32 target_fd; /* container object to query */
__u32 attach_type;
__u32 query_flags;
__u32 attach_flags;
__aligned_u64 prog_ids;
__u32 prog_cnt;
} query;
struct {
__u64 name;
__u32 prog_fd;
} raw_tracepoint;
struct { /* anonymous struct for BPF_BTF_LOAD */
__aligned_u64 btf;
__aligned_u64 btf_log_buf;
__u32 btf_size;
__u32 btf_log_size;
__u32 btf_log_level;
};
struct {
__u32 pid; /* input: pid */
__u32 fd; /* input: fd */
__u32 flags; /* input: flags */
__u32 buf_len; /* input/output: buf len */
__aligned_u64 buf; /* input/output:
* tp_name for tracepoint
* symbol for kprobe
* filename for uprobe
*/
__u32 prog_id; /* output: prod_id */
__u32 fd_type; /* output: BPF_FD_TYPE_* */
__u64 probe_offset; /* output: probe_offset */
__u64 probe_addr; /* output: probe_addr */
} task_fd_query;
} __attribute__((aligned(8)));
/* The description below is an attempt at providing documentation to eBPF
* developers about the multiple available eBPF helper functions. It can be
* parsed and used to produce a manual page. The workflow is the following,
* and requires the rst2man utility:
*
* $ ./scripts/bpf_helpers_doc.py \
* --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
* $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
* $ man /tmp/bpf-helpers.7
*
* Note that in order to produce this external documentation, some RST
* formatting is used in the descriptions to get "bold" and "italics" in
* manual pages. Also note that the few trailing white spaces are
* intentional, removing them would break paragraphs for rst2man.
*
* Start of BPF helper function descriptions:
*
* void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
* Description
* Perform a lookup in *map* for an entry associated to *key*.
* Return
* Map value associated to *key*, or **NULL** if no entry was
* found.
*
* int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
* Description
* Add or update the value of the entry associated to *key* in
* *map* with *value*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* Flag value **BPF_NOEXIST** cannot be used for maps of types
* **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
* elements always exist), the helper would return an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_map_delete_elem(struct bpf_map *map, const void *key)
* Description
* Delete entry with *key* from *map*.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_probe_read(void *dst, u32 size, const void *src)
* Description
* For tracing programs, safely attempt to read *size* bytes from
* address *src* and store the data in *dst*.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_ktime_get_ns(void)
* Description
* Return the time elapsed since system boot, in nanoseconds.
* Return
* Current *ktime*.
*
* int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
* Description
* This helper is a "printk()-like" facility for debugging. It
* prints a message defined by format *fmt* (of size *fmt_size*)
* to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
* available. It can take up to three additional **u64**
* arguments (as an eBPF helpers, the total number of arguments is
* limited to five).
*
* Each time the helper is called, it appends a line to the trace.
* Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
* open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
* The format of the trace is customizable, and the exact output
* one will get depends on the options set in
* *\/sys/kernel/debug/tracing/trace_options* (see also the
* *README* file under the same directory). However, it usually
* defaults to something like:
*
* ::
*
* telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
*
* In the above:
*
* * ``telnet`` is the name of the current task.
* * ``470`` is the PID of the current task.
* * ``001`` is the CPU number on which the task is
* running.
* * In ``.N..``, each character refers to a set of
* options (whether irqs are enabled, scheduling
* options, whether hard/softirqs are running, level of
* preempt_disabled respectively). **N** means that
* **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
* are set.
* * ``419421.045894`` is a timestamp.
* * ``0x00000001`` is a fake value used by BPF for the
* instruction pointer register.
* * ``<formatted msg>`` is the message formatted with
* *fmt*.
*
* The conversion specifiers supported by *fmt* are similar, but
* more limited than for printk(). They are **%d**, **%i**,
* **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
* **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
* of field, padding with zeroes, etc.) is available, and the
* helper will return **-EINVAL** (but print nothing) if it
* encounters an unknown specifier.
*
* Also, note that **bpf_trace_printk**\ () is slow, and should
* only be used for debugging purposes. For this reason, a notice
* bloc (spanning several lines) is printed to kernel logs and
* states that the helper should not be used "for production use"
* the first time this helper is used (or more precisely, when
* **trace_printk**\ () buffers are allocated). For passing values
* to user space, perf events should be preferred.
* Return
* The number of bytes written to the buffer, or a negative error
* in case of failure.
*
* u32 bpf_get_prandom_u32(void)
* Description
* Get a pseudo-random number.
*
* From a security point of view, this helper uses its own
* pseudo-random internal state, and cannot be used to infer the
* seed of other random functions in the kernel. However, it is
* essential to note that the generator used by the helper is not
* cryptographically secure.
* Return
* A random 32-bit unsigned value.
*
* u32 bpf_get_smp_processor_id(void)
* Description
* Get the SMP (symmetric multiprocessing) processor id. Note that
* all programs run with preemption disabled, which means that the
* SMP processor id is stable during all the execution of the
* program.
* Return
* The SMP id of the processor running the program.
*
* int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
* Description
* Store *len* bytes from address *from* into the packet
* associated to *skb*, at *offset*. *flags* are a combination of
* **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
* checksum for the packet after storing the bytes) and
* **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
* **->swhash** and *skb*\ **->l4hash** to 0).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
* Description
* Recompute the layer 3 (e.g. IP) checksum for the packet
* associated to *skb*. Computation is incremental, so the helper
* must know the former value of the header field that was
* modified (*from*), the new value of this field (*to*), and the
* number of bytes (2 or 4) for this field, stored in *size*.
* Alternatively, it is possible to store the difference between
* the previous and the new values of the header field in *to*, by
* setting *from* and *size* to 0. For both methods, *offset*
* indicates the location of the IP checksum within the packet.
*
* This helper works in combination with **bpf_csum_diff**\ (),
* which does not update the checksum in-place, but offers more
* flexibility and can handle sizes larger than 2 or 4 for the
* checksum to update.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
* Description
* Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
* packet associated to *skb*. Computation is incremental, so the
* helper must know the former value of the header field that was
* modified (*from*), the new value of this field (*to*), and the
* number of bytes (2 or 4) for this field, stored on the lowest
* four bits of *flags*. Alternatively, it is possible to store
* the difference between the previous and the new values of the
* header field in *to*, by setting *from* and the four lowest
* bits of *flags* to 0. For both methods, *offset* indicates the
* location of the IP checksum within the packet. In addition to
* the size of the field, *flags* can be added (bitwise OR) actual
* flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
* untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
* for updates resulting in a null checksum the value is set to
* **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
* the checksum is to be computed against a pseudo-header.
*
* This helper works in combination with **bpf_csum_diff**\ (),
* which does not update the checksum in-place, but offers more
* flexibility and can handle sizes larger than 2 or 4 for the
* checksum to update.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
* Description
* This special helper is used to trigger a "tail call", or in
* other words, to jump into another eBPF program. The same stack
* frame is used (but values on stack and in registers for the
* caller are not accessible to the callee). This mechanism allows
* for program chaining, either for raising the maximum number of
* available eBPF instructions, or to execute given programs in
* conditional blocks. For security reasons, there is an upper
* limit to the number of successive tail calls that can be
* performed.
*
* Upon call of this helper, the program attempts to jump into a
* program referenced at index *index* in *prog_array_map*, a
* special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
* *ctx*, a pointer to the context.
*
* If the call succeeds, the kernel immediately runs the first
* instruction of the new program. This is not a function call,
* and it never returns to the previous program. If the call
* fails, then the helper has no effect, and the caller continues
* to run its subsequent instructions. A call can fail if the
* destination program for the jump does not exist (i.e. *index*
* is superior to the number of entries in *prog_array_map*), or
* if the maximum number of tail calls has been reached for this
* chain of programs. This limit is defined in the kernel by the
* macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
* which is currently set to 32.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
* Description
* Clone and redirect the packet associated to *skb* to another
* net device of index *ifindex*. Both ingress and egress
* interfaces can be used for redirection. The **BPF_F_INGRESS**
* value in *flags* is used to make the distinction (ingress path
* is selected if the flag is present, egress path otherwise).
* This is the only flag supported for now.
*
* In comparison with **bpf_redirect**\ () helper,
* **bpf_clone_redirect**\ () has the associated cost of
* duplicating the packet buffer, but this can be executed out of
* the eBPF program. Conversely, **bpf_redirect**\ () is more
* efficient, but it is handled through an action code where the
* redirection happens only after the eBPF program has returned.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure. Positive
* error indicates a potential drop or congestion in the target
* device. The particular positive error codes are not defined.
*
* u64 bpf_get_current_pid_tgid(void)
* Return
* A 64-bit integer containing the current tgid and pid, and
* created as such:
* *current_task*\ **->tgid << 32 \|**
* *current_task*\ **->pid**.
*
* u64 bpf_get_current_uid_gid(void)
* Return
* A 64-bit integer containing the current GID and UID, and
* created as such: *current_gid* **<< 32 \|** *current_uid*.
*
* int bpf_get_current_comm(char *buf, u32 size_of_buf)
* Description
* Copy the **comm** attribute of the current task into *buf* of
* *size_of_buf*. The **comm** attribute contains the name of
* the executable (excluding the path) for the current task. The
* *size_of_buf* must be strictly positive. On success, the
* helper makes sure that the *buf* is NUL-terminated. On failure,
* it is filled with zeroes.
* Return
* 0 on success, or a negative error in case of failure.
*
* u32 bpf_get_cgroup_classid(struct sk_buff *skb)
* Description
* Retrieve the classid for the current task, i.e. for the net_cls
* cgroup to which *skb* belongs.
*
* This helper can be used on TC egress path, but not on ingress.
*
* The net_cls cgroup provides an interface to tag network packets
* based on a user-provided identifier for all traffic coming from
* the tasks belonging to the related cgroup. See also the related
* kernel documentation, available from the Linux sources in file
* *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
*
* The Linux kernel has two versions for cgroups: there are
* cgroups v1 and cgroups v2. Both are available to users, who can
* use a mixture of them, but note that the net_cls cgroup is for
* cgroup v1 only. This makes it incompatible with BPF programs
* run on cgroups, which is a cgroup-v2-only feature (a socket can
* only hold data for one version of cgroups at a time).
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
* "**y**" or to "**m**".
* Return
* The classid, or 0 for the default unconfigured classid.
*
* int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
* Description
* Push a *vlan_tci* (VLAN tag control information) of protocol
* *vlan_proto* to the packet associated to *skb*, then update
* the checksum. Note that if *vlan_proto* is different from
* **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
* be **ETH_P_8021Q**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_vlan_pop(struct sk_buff *skb)
* Description
* Pop a VLAN header from the packet associated to *skb*.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
* Description
* Get tunnel metadata. This helper takes a pointer *key* to an
* empty **struct bpf_tunnel_key** of **size**, that will be
* filled with tunnel metadata for the packet associated to *skb*.
* The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
* indicates that the tunnel is based on IPv6 protocol instead of
* IPv4.
*
* The **struct bpf_tunnel_key** is an object that generalizes the
* principal parameters used by various tunneling protocols into a
* single struct. This way, it can be used to easily make a
* decision based on the contents of the encapsulation header,
* "summarized" in this struct. In particular, it holds the IP
* address of the remote end (IPv4 or IPv6, depending on the case)
* in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
* this struct exposes the *key*\ **->tunnel_id**, which is
* generally mapped to a VNI (Virtual Network Identifier), making
* it programmable together with the **bpf_skb_set_tunnel_key**\
* () helper.
*
* Let's imagine that the following code is part of a program
* attached to the TC ingress interface, on one end of a GRE
* tunnel, and is supposed to filter out all messages coming from
* remote ends with IPv4 address other than 10.0.0.1:
*
* ::
*
* int ret;
* struct bpf_tunnel_key key = {};
*
* ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
* if (ret < 0)
* return TC_ACT_SHOT; // drop packet
*
* if (key.remote_ipv4 != 0x0a000001)
* return TC_ACT_SHOT; // drop packet
*
* return TC_ACT_OK; // accept packet
*
* This interface can also be used with all encapsulation devices
* that can operate in "collect metadata" mode: instead of having
* one network device per specific configuration, the "collect
* metadata" mode only requires a single device where the
* configuration can be extracted from this helper.
*
* This can be used together with various tunnels such as VXLan,
* Geneve, GRE or IP in IP (IPIP).
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
* Description
* Populate tunnel metadata for packet associated to *skb.* The
* tunnel metadata is set to the contents of *key*, of *size*. The
* *flags* can be set to a combination of the following values:
*
* **BPF_F_TUNINFO_IPV6**
* Indicate that the tunnel is based on IPv6 protocol
* instead of IPv4.
* **BPF_F_ZERO_CSUM_TX**
* For IPv4 packets, add a flag to tunnel metadata
* indicating that checksum computation should be skipped
* and checksum set to zeroes.
* **BPF_F_DONT_FRAGMENT**
* Add a flag to tunnel metadata indicating that the
* packet should not be fragmented.
* **BPF_F_SEQ_NUMBER**
* Add a flag to tunnel metadata indicating that a
* sequence number should be added to tunnel header before
* sending the packet. This flag was added for GRE
* encapsulation, but might be used with other protocols
* as well in the future.
*
* Here is a typical usage on the transmit path:
*
* ::
*
* struct bpf_tunnel_key key;
* populate key ...
* bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
* bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
*
* See also the description of the **bpf_skb_get_tunnel_key**\ ()
* helper for additional information.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
* Description
* Read the value of a perf event counter. This helper relies on a
* *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
* the perf event counter is selected when *map* is updated with
* perf event file descriptors. The *map* is an array whose size
* is the number of available CPUs, and each cell contains a value
* relative to one CPU. The value to retrieve is indicated by
* *flags*, that contains the index of the CPU to look up, masked
* with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
* **BPF_F_CURRENT_CPU** to indicate that the value for the
* current CPU should be retrieved.
*
* Note that before Linux 4.13, only hardware perf event can be
* retrieved.
*
* Also, be aware that the newer helper
* **bpf_perf_event_read_value**\ () is recommended over
* **bpf_perf_event_read**\ () in general. The latter has some ABI
* quirks where error and counter value are used as a return code
* (which is wrong to do since ranges may overlap). This issue is
* fixed with **bpf_perf_event_read_value**\ (), which at the same
* time provides more features over the **bpf_perf_event_read**\
* () interface. Please refer to the description of
* **bpf_perf_event_read_value**\ () for details.
* Return
* The value of the perf event counter read from the map, or a
* negative error code in case of failure.
*
* int bpf_redirect(u32 ifindex, u64 flags)
* Description
* Redirect the packet to another net device of index *ifindex*.
* This helper is somewhat similar to **bpf_clone_redirect**\
* (), except that the packet is not cloned, which provides
* increased performance.
*
* Except for XDP, both ingress and egress interfaces can be used
* for redirection. The **BPF_F_INGRESS** value in *flags* is used
* to make the distinction (ingress path is selected if the flag
* is present, egress path otherwise). Currently, XDP only
* supports redirection to the egress interface, and accepts no
* flag at all.
*
* The same effect can be attained with the more generic
* **bpf_redirect_map**\ (), which requires specific maps to be
* used but offers better performance.
* Return
* For XDP, the helper returns **XDP_REDIRECT** on success or
* **XDP_ABORTED** on error. For other program types, the values
* are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
* error.
*
* u32 bpf_get_route_realm(struct sk_buff *skb)
* Description
* Retrieve the realm or the route, that is to say the
* **tclassid** field of the destination for the *skb*. The
* indentifier retrieved is a user-provided tag, similar to the
* one used with the net_cls cgroup (see description for
* **bpf_get_cgroup_classid**\ () helper), but here this tag is
* held by a route (a destination entry), not by a task.
*
* Retrieving this identifier works with the clsact TC egress hook
* (see also **tc-bpf(8)**), or alternatively on conventional
* classful egress qdiscs, but not on TC ingress path. In case of
* clsact TC egress hook, this has the advantage that, internally,
* the destination entry has not been dropped yet in the transmit
* path. Therefore, the destination entry does not need to be
* artificially held via **netif_keep_dst**\ () for a classful
* qdisc until the *skb* is freed.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_IP_ROUTE_CLASSID** configuration option.
* Return
* The realm of the route for the packet associated to *skb*, or 0
* if none was found.
*
* int bpf_perf_event_output(struct pt_regs *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
* Description
* Write raw *data* blob into a special BPF perf event held by
* *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
* event must have the following attributes: **PERF_SAMPLE_RAW**
* as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
* **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
*
* The *flags* are used to indicate the index in *map* for which
* the value must be put, masked with **BPF_F_INDEX_MASK**.
* Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
* to indicate that the index of the current CPU core should be
* used.
*
* The value to write, of *size*, is passed through eBPF stack and
* pointed by *data*.
*
* The context of the program *ctx* needs also be passed to the
* helper.
*
* On user space, a program willing to read the values needs to
* call **perf_event_open**\ () on the perf event (either for
* one or for all CPUs) and to store the file descriptor into the
* *map*. This must be done before the eBPF program can send data
* into it. An example is available in file
* *samples/bpf/trace_output_user.c* in the Linux kernel source
* tree (the eBPF program counterpart is in
* *samples/bpf/trace_output_kern.c*).
*
* **bpf_perf_event_output**\ () achieves better performance
* than **bpf_trace_printk**\ () for sharing data with user
* space, and is much better suitable for streaming data from eBPF
* programs.
*
* Note that this helper is not restricted to tracing use cases
* and can be used with programs attached to TC or XDP as well,
* where it allows for passing data to user space listeners. Data
* can be:
*
* * Only custom structs,
* * Only the packet payload, or
* * A combination of both.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
* Description
* This helper was provided as an easy way to load data from a
* packet. It can be used to load *len* bytes from *offset* from
* the packet associated to *skb*, into the buffer pointed by
* *to*.
*
* Since Linux 4.7, usage of this helper has mostly been replaced
* by "direct packet access", enabling packet data to be
* manipulated with *skb*\ **->data** and *skb*\ **->data_end**
* pointing respectively to the first byte of packet data and to
* the byte after the last byte of packet data. However, it
* remains useful if one wishes to read large quantities of data
* at once from a packet into the eBPF stack.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_get_stackid(struct pt_regs *ctx, struct bpf_map *map, u64 flags)
* Description
* Walk a user or a kernel stack and return its id. To achieve
* this, the helper needs *ctx*, which is a pointer to the context
* on which the tracing program is executed, and a pointer to a
* *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
*
* The last argument, *flags*, holds the number of stack frames to
* skip (from 0 to 255), masked with
* **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
* a combination of the following flags:
*
* **BPF_F_USER_STACK**
* Collect a user space stack instead of a kernel stack.
* **BPF_F_FAST_STACK_CMP**
* Compare stacks by hash only.
* **BPF_F_REUSE_STACKID**
* If two different stacks hash into the same *stackid*,
* discard the old one.
*
* The stack id retrieved is a 32 bit long integer handle which
* can be further combined with other data (including other stack
* ids) and used as a key into maps. This can be useful for
* generating a variety of graphs (such as flame graphs or off-cpu
* graphs).
*
* For walking a stack, this helper is an improvement over
* **bpf_probe_read**\ (), which can be used with unrolled loops
* but is not efficient and consumes a lot of eBPF instructions.
* Instead, **bpf_get_stackid**\ () can collect up to
* **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
* this limit can be controlled with the **sysctl** program, and
* that it should be manually increased in order to profile long
* user stacks (such as stacks for Java programs). To do so, use:
*
* ::
*
* # sysctl kernel.perf_event_max_stack=<new value>
* Return
* The positive or null stack id on success, or a negative error
* in case of failure.
*
* s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
* Description
* Compute a checksum difference, from the raw buffer pointed by
* *from*, of length *from_size* (that must be a multiple of 4),
* towards the raw buffer pointed by *to*, of size *to_size*
* (same remark). An optional *seed* can be added to the value
* (this can be cascaded, the seed may come from a previous call
* to the helper).
*
* This is flexible enough to be used in several ways:
*
* * With *from_size* == 0, *to_size* > 0 and *seed* set to
* checksum, it can be used when pushing new data.
* * With *from_size* > 0, *to_size* == 0 and *seed* set to
* checksum, it can be used when removing data from a packet.
* * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
* can be used to compute a diff. Note that *from_size* and
* *to_size* do not need to be equal.
*
* This helper can be used in combination with
* **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
* which one can feed in the difference computed with
* **bpf_csum_diff**\ ().
* Return
* The checksum result, or a negative error code in case of
* failure.
*
* int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
* Description
* Retrieve tunnel options metadata for the packet associated to
* *skb*, and store the raw tunnel option data to the buffer *opt*
* of *size*.
*
* This helper can be used with encapsulation devices that can
* operate in "collect metadata" mode (please refer to the related
* note in the description of **bpf_skb_get_tunnel_key**\ () for
* more details). A particular example where this can be used is
* in combination with the Geneve encapsulation protocol, where it
* allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
* and retrieving arbitrary TLVs (Type-Length-Value headers) from
* the eBPF program. This allows for full customization of these
* headers.
* Return
* The size of the option data retrieved.
*
* int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
* Description
* Set tunnel options metadata for the packet associated to *skb*
* to the option data contained in the raw buffer *opt* of *size*.
*
* See also the description of the **bpf_skb_get_tunnel_opt**\ ()
* helper for additional information.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
* Description
* Change the protocol of the *skb* to *proto*. Currently
* supported are transition from IPv4 to IPv6, and from IPv6 to
* IPv4. The helper takes care of the groundwork for the
* transition, including resizing the socket buffer. The eBPF
* program is expected to fill the new headers, if any, via
* **skb_store_bytes**\ () and to recompute the checksums with
* **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
* (). The main case for this helper is to perform NAT64
* operations out of an eBPF program.
*
* Internally, the GSO type is marked as dodgy so that headers are
* checked and segments are recalculated by the GSO/GRO engine.
* The size for GSO target is adapted as well.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_change_type(struct sk_buff *skb, u32 type)
* Description
* Change the packet type for the packet associated to *skb*. This
* comes down to setting *skb*\ **->pkt_type** to *type*, except
* the eBPF program does not have a write access to *skb*\
* **->pkt_type** beside this helper. Using a helper here allows
* for graceful handling of errors.
*
* The major use case is to change incoming *skb*s to
* **PACKET_HOST** in a programmatic way instead of having to
* recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
* example.
*
* Note that *type* only allows certain values. At this time, they
* are:
*
* **PACKET_HOST**
* Packet is for us.
* **PACKET_BROADCAST**
* Send packet to all.
* **PACKET_MULTICAST**
* Send packet to group.
* **PACKET_OTHERHOST**
* Send packet to someone else.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
* Description
* Check whether *skb* is a descendant of the cgroup2 held by
* *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
* Return
* The return value depends on the result of the test, and can be:
*
* * 0, if the *skb* failed the cgroup2 descendant test.
* * 1, if the *skb* succeeded the cgroup2 descendant test.
* * A negative error code, if an error occurred.
*
* u32 bpf_get_hash_recalc(struct sk_buff *skb)
* Description
* Retrieve the hash of the packet, *skb*\ **->hash**. If it is
* not set, in particular if the hash was cleared due to mangling,
* recompute this hash. Later accesses to the hash can be done
* directly with *skb*\ **->hash**.
*
* Calling **bpf_set_hash_invalid**\ (), changing a packet
* prototype with **bpf_skb_change_proto**\ (), or calling
* **bpf_skb_store_bytes**\ () with the
* **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
* the hash and to trigger a new computation for the next call to
* **bpf_get_hash_recalc**\ ().
* Return
* The 32-bit hash.
*
* u64 bpf_get_current_task(void)
* Return
* A pointer to the current task struct.
*
* int bpf_probe_write_user(void *dst, const void *src, u32 len)
* Description
* Attempt in a safe way to write *len* bytes from the buffer
* *src* to *dst* in memory. It only works for threads that are in
* user context, and *dst* must be a valid user space address.
*
* This helper should not be used to implement any kind of
* security mechanism because of TOC-TOU attacks, but rather to
* debug, divert, and manipulate execution of semi-cooperative
* processes.
*
* Keep in mind that this feature is meant for experiments, and it
* has a risk of crashing the system and running programs.
* Therefore, when an eBPF program using this helper is attached,
* a warning including PID and process name is printed to kernel
* logs.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
* Description
* Check whether the probe is being run is the context of a given
* subset of the cgroup2 hierarchy. The cgroup2 to test is held by
* *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
* Return
* The return value depends on the result of the test, and can be:
*
* * 1, if current task belongs to the cgroup2.
* * 0, if current task does not belong to the cgroup2.
* * A negative error code, if an error occurred.
*
* int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
* Description
* Resize (trim or grow) the packet associated to *skb* to the
* new *len*. The *flags* are reserved for future usage, and must
* be left at zero.
*
* The basic idea is that the helper performs the needed work to
* change the size of the packet, then the eBPF program rewrites
* the rest via helpers like **bpf_skb_store_bytes**\ (),
* **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
* and others. This helper is a slow path utility intended for
* replies with control messages. And because it is targeted for
* slow path, the helper itself can afford to be slow: it
* implicitly linearizes, unclones and drops offloads from the
* *skb*.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
* Description
* Pull in non-linear data in case the *skb* is non-linear and not
* all of *len* are part of the linear section. Make *len* bytes
* from *skb* readable and writable. If a zero value is passed for
* *len*, then the whole length of the *skb* is pulled.
*
* This helper is only needed for reading and writing with direct
* packet access.
*
* For direct packet access, testing that offsets to access
* are within packet boundaries (test on *skb*\ **->data_end**) is
* susceptible to fail if offsets are invalid, or if the requested
* data is in non-linear parts of the *skb*. On failure the
* program can just bail out, or in the case of a non-linear
* buffer, use a helper to make the data available. The
* **bpf_skb_load_bytes**\ () helper is a first solution to access
* the data. Another one consists in using **bpf_skb_pull_data**
* to pull in once the non-linear parts, then retesting and
* eventually access the data.
*
* At the same time, this also makes sure the *skb* is uncloned,
* which is a necessary condition for direct write. As this needs
* to be an invariant for the write part only, the verifier
* detects writes and adds a prologue that is calling
* **bpf_skb_pull_data()** to effectively unclone the *skb* from
* the very beginning in case it is indeed cloned.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
* Description
* Add the checksum *csum* into *skb*\ **->csum** in case the
* driver has supplied a checksum for the entire packet into that
* field. Return an error otherwise. This helper is intended to be
* used in combination with **bpf_csum_diff**\ (), in particular
* when the checksum needs to be updated after data has been
* written into the packet through direct packet access.
* Return
* The checksum on success, or a negative error code in case of
* failure.
*
* void bpf_set_hash_invalid(struct sk_buff *skb)
* Description
* Invalidate the current *skb*\ **->hash**. It can be used after
* mangling on headers through direct packet access, in order to
* indicate that the hash is outdated and to trigger a
* recalculation the next time the kernel tries to access this
* hash or when the **bpf_get_hash_recalc**\ () helper is called.
*
* int bpf_get_numa_node_id(void)
* Description
* Return the id of the current NUMA node. The primary use case
* for this helper is the selection of sockets for the local NUMA
* node, when the program is attached to sockets using the
* **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
* but the helper is also available to other eBPF program types,
* similarly to **bpf_get_smp_processor_id**\ ().
* Return
* The id of current NUMA node.
*
* int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
* Description
* Grows headroom of packet associated to *skb* and adjusts the
* offset of the MAC header accordingly, adding *len* bytes of
* space. It automatically extends and reallocates memory as
* required.
*
* This helper can be used on a layer 3 *skb* to push a MAC header
* for redirection into a layer 2 device.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
* it is possible to use a negative value for *delta*. This helper
* can be used to prepare the packet for pushing or popping
* headers.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
* Description
* Copy a NUL terminated string from an unsafe address
* *unsafe_ptr* to *dst*. The *size* should include the
* terminating NUL byte. In case the string length is smaller than
* *size*, the target is not padded with further NUL bytes. If the
* string length is larger than *size*, just *size*-1 bytes are
* copied and the last byte is set to NUL.
*
* On success, the length of the copied string is returned. This
* makes this helper useful in tracing programs for reading
* strings, and more importantly to get its length at runtime. See
* the following snippet:
*
* ::
*
* SEC("kprobe/sys_open")
* void bpf_sys_open(struct pt_regs *ctx)
* {
* char buf[PATHLEN]; // PATHLEN is defined to 256
* int res = bpf_probe_read_str(buf, sizeof(buf),
* ctx->di);
*
* // Consume buf, for example push it to
* // userspace via bpf_perf_event_output(); we
* // can use res (the string length) as event
* // size, after checking its boundaries.
* }
*
* In comparison, using **bpf_probe_read()** helper here instead
* to read the string would require to estimate the length at
* compile time, and would often result in copying more memory
* than necessary.
*
* Another useful use case is when parsing individual process
* arguments or individual environment variables navigating
* *current*\ **->mm->arg_start** and *current*\
* **->mm->env_start**: using this helper and the return value,
* one can quickly iterate at the right offset of the memory area.
* Return
* On success, the strictly positive length of the string,
* including the trailing NUL character. On error, a negative
* value.
*
* u64 bpf_get_socket_cookie(struct sk_buff *skb)
* Description
* If the **struct sk_buff** pointed by *skb* has a known socket,
* retrieve the cookie (generated by the kernel) of this socket.
* If no cookie has been set yet, generate a new cookie. Once
* generated, the socket cookie remains stable for the life of the
* socket. This helper can be useful for monitoring per socket
* networking traffic statistics as it provides a global socket
* identifier that can be assumed unique.
* Return
* A 8-byte long non-decreasing number on success, or 0 if the
* socket field is missing inside *skb*.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
* *skb*, but gets socket from **struct bpf_sock_addr** context.
* Return
* A 8-byte long non-decreasing number.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
* *skb*, but gets socket from **struct bpf_sock_ops** context.
* Return
* A 8-byte long non-decreasing number.
*
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Return
* The owner UID of the socket associated to *skb*. If the socket
* is **NULL**, or if it is not a full socket (i.e. if it is a
* time-wait or a request socket instead), **overflowuid** value
* is returned (note that **overflowuid** might also be the actual
* UID value for the socket).
*
* u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
* Description
* Set the full hash for *skb* (set the field *skb*\ **->hash**)
* to value *hash*.
* Return
* 0
*
* int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
* Description
* Emulate a call to **setsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
* which the option resides and the name *optname* of the option
* must be specified, see **setsockopt(2)** for more information.
* The option value of length *optlen* is pointed by *optval*.
*
* This helper actually implements a subset of **setsockopt()**.
* It supports the following *level*\ s:
*
* * **SOL_SOCKET**, which supports the following *optname*\ s:
* **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
* **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
* * **IPPROTO_TCP**, which supports the following *optname*\ s:
* **TCP_CONGESTION**, **TCP_BPF_IW**,
* **TCP_BPF_SNDCWND_CLAMP**.
* * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
* * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
* Description
* Grow or shrink the room for data in the packet associated to
* *skb* by *len_diff*, and according to the selected *mode*.
*
* There are two supported modes at this time:
*
* * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
* (room space is added or removed below the layer 2 header).
*
* * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
* (room space is added or removed below the layer 3 header).
*
* The following flags are supported at this time:
*
* * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
* Adjusting mss in this way is not allowed for datagrams.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
* Any new space is reserved to hold a tunnel header.
* Configure skb offsets and other fields accordingly.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
* **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
* Use with ENCAP_L3 flags to further specify the tunnel type.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
* Use with ENCAP_L3/L4 flags to further specify the tunnel
* type; *len* is the length of the inner MAC header.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
* Description
* Redirect the packet to the endpoint referenced by *map* at
* index *key*. Depending on its type, this *map* can contain
* references to net devices (for forwarding packets through other
* ports), or to CPUs (for redirecting XDP frames to another CPU;
* but this is only implemented for native XDP (with driver
* support) as of this writing).
*
* The lower two bits of *flags* are used as the return code if
* the map lookup fails. This is so that the return value can be
* one of the XDP program return codes up to XDP_TX, as chosen by
* the caller. Any higher bits in the *flags* argument must be
* unset.
*
* When used to redirect packets to net devices, this helper
* provides a high performance increase over **bpf_redirect**\ ().
* This is due to various implementation details of the underlying
* mechanisms, one of which is the fact that **bpf_redirect_map**\
* () tries to send packet as a "bulk" to the device.
* Return
* **XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
*
* int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
* Description
* Redirect the packet to the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
* Description
* Add an entry to, or update a *map* referencing sockets. The
* *skops* is used as a new value for the entry associated to
* *key*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* If the *map* has eBPF programs (parser and verdict), those will
* be inherited by the socket being added. If the socket is
* already attached to eBPF programs, this results in an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust the address pointed by *xdp_md*\ **->data_meta** by
* *delta* (which can be positive or negative). Note that this
* operation modifies the address stored in *xdp_md*\ **->data**,
* so the latter must be loaded only after the helper has been
* called.
*
* The use of *xdp_md*\ **->data_meta** is optional and programs
* are not required to use it. The rationale is that when the
* packet is processed with XDP (e.g. as DoS filter), it is
* possible to push further meta data along with it before passing
* to the stack, and to give the guarantee that an ingress eBPF
* program attached as a TC classifier on the same device can pick
* this up for further post-processing. Since TC works with socket
* buffers, it remains possible to set from XDP the **mark** or
* **priority** pointers, or other pointers for the socket buffer.
* Having this scratch space generic and programmable allows for
* more flexibility as the user is free to store whatever meta
* data they need.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
* Description
* Read the value of a perf event counter, and store it into *buf*
* of size *buf_size*. This helper relies on a *map* of type
* **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
* counter is selected when *map* is updated with perf event file
* descriptors. The *map* is an array whose size is the number of
* available CPUs, and each cell contains a value relative to one
* CPU. The value to retrieve is indicated by *flags*, that
* contains the index of the CPU to look up, masked with
* **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
* **BPF_F_CURRENT_CPU** to indicate that the value for the
* current CPU should be retrieved.
*
* This helper behaves in a way close to
* **bpf_perf_event_read**\ () helper, save that instead of
* just returning the value observed, it fills the *buf*
* structure. This allows for additional data to be retrieved: in
* particular, the enabled and running times (in *buf*\
* **->enabled** and *buf*\ **->running**, respectively) are
* copied. In general, **bpf_perf_event_read_value**\ () is
* recommended over **bpf_perf_event_read**\ (), which has some
* ABI issues and provides fewer functionalities.
*
* These values are interesting, because hardware PMU (Performance
* Monitoring Unit) counters are limited resources. When there are
* more PMU based perf events opened than available counters,
* kernel will multiplex these events so each event gets certain
* percentage (but not all) of the PMU time. In case that
* multiplexing happens, the number of samples or counter value
* will not reflect the case compared to when no multiplexing
* occurs. This makes comparison between different runs difficult.
* Typically, the counter value should be normalized before
* comparing to other experiments. The usual normalization is done
* as follows.
*
* ::
*
* normalized_counter = counter * t_enabled / t_running
*
* Where t_enabled is the time enabled for event and t_running is
* the time running for event since last normalization. The
* enabled and running times are accumulated since the perf event
* open. To achieve scaling factor between two invocations of an
* eBPF program, users can can use CPU id as the key (which is
* typical for perf array usage model) to remember the previous
* value and do the calculation inside the eBPF program.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
* Description
* For en eBPF program attached to a perf event, retrieve the
* value of the event counter associated to *ctx* and store it in
* the structure pointed by *buf* and of size *buf_size*. Enabled
* and running times are also stored in the structure (see
* description of helper **bpf_perf_event_read_value**\ () for
* more details).
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
* Description
* Emulate a call to **getsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
* which the option resides and the name *optname* of the option
* must be specified, see **getsockopt(2)** for more information.
* The retrieved value is stored in the structure pointed by
* *opval* and of length *optlen*.
*
* This helper actually implements a subset of **getsockopt()**.
* It supports the following *level*\ s:
*
* * **IPPROTO_TCP**, which supports *optname*
* **TCP_CONGESTION**.
* * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
* * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_override_return(struct pt_regs *regs, u64 rc)
* Description
* Used for error injection, this helper uses kprobes to override
* the return value of the probed function, and to set it to *rc*.
* The first argument is the context *regs* on which the kprobe
* works.
*
* This helper works by setting setting the PC (program counter)
* to an override function which is run in place of the original
* probed function. This means the probed function is not run at
* all. The replacement function just returns with the required
* value.
*
* This helper has security implications, and thus is subject to
* restrictions. It is only available if the kernel was compiled
* with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
* option, and in this case it only works on functions tagged with
* **ALLOW_ERROR_INJECTION** in the kernel code.
*
* Also, the helper is only available for the architectures having
* the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
* x86 architecture is the only one to support this feature.
* Return
* 0
*
* int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
* Description
* Attempt to set the value of the **bpf_sock_ops_cb_flags** field
* for the full TCP socket associated to *bpf_sock_ops* to
* *argval*.
*
* The primary use of this field is to determine if there should
* be calls to eBPF programs of type
* **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
* code. A program of the same type can change its value, per
* connection and as necessary, when the connection is
* established. This field is directly accessible for reading, but
* this helper must be used for updates in order to return an
* error if an eBPF program tries to set a callback that is not
* supported in the current kernel.
*
* *argval* is a flag array which can combine these flags:
*
* * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
* * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
* * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
* * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
*
* Therefore, this function can be used to clear a callback flag by
* setting the appropriate bit to zero. e.g. to disable the RTO
* callback:
*
* **bpf_sock_ops_cb_flags_set(bpf_sock,**
* **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
*
* Here are some examples of where one could call such eBPF
* program:
*
* * When RTO fires.
* * When a packet is retransmitted.
* * When the connection terminates.
* * When a packet is sent.
* * When a packet is received.
* Return
* Code **-EINVAL** if the socket is not a full TCP socket;
* otherwise, a positive number containing the bits that could not
* be set is returned (which comes down to 0 if all bits were set
* as required).
*
* int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* socket level. If the message *msg* is allowed to pass (i.e. if
* the verdict eBPF program returns **SK_PASS**), redirect it to
* the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
* Description
* For socket policies, apply the verdict of the eBPF program to
* the next *bytes* (number of bytes) of message *msg*.
*
* For example, this helper can be used in the following cases:
*
* * A single **sendmsg**\ () or **sendfile**\ () system call
* contains multiple logical messages that the eBPF program is
* supposed to read and for which it should apply a verdict.
* * An eBPF program only cares to read the first *bytes* of a
* *msg*. If the message has a large payload, then setting up
* and calling the eBPF program repeatedly for all bytes, even
* though the verdict is already known, would create unnecessary
* overhead.
*
* When called from within an eBPF program, the helper sets a
* counter internal to the BPF infrastructure, that is used to
* apply the last verdict to the next *bytes*. If *bytes* is
* smaller than the current data being processed from a
* **sendmsg**\ () or **sendfile**\ () system call, the first
* *bytes* will be sent and the eBPF program will be re-run with
* the pointer for start of data pointing to byte number *bytes*
* **+ 1**. If *bytes* is larger than the current data being
* processed, then the eBPF verdict will be applied to multiple
* **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
* consumed.
*
* Note that if a socket closes with the internal counter holding
* a non-zero value, this is not a problem because data is not
* being buffered for *bytes* and is sent as it is received.
* Return
* 0
*
* int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
* Description
* For socket policies, prevent the execution of the verdict eBPF
* program for message *msg* until *bytes* (byte number) have been
* accumulated.
*
* This can be used when one needs a specific number of bytes
* before a verdict can be assigned, even if the data spans
* multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
* case would be a user calling **sendmsg**\ () repeatedly with
* 1-byte long message segments. Obviously, this is bad for
* performance, but it is still valid. If the eBPF program needs
* *bytes* bytes to validate a header, this helper can be used to
* prevent the eBPF program to be called again until *bytes* have
* been accumulated.
* Return
* 0
*
* int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
* Description
* For socket policies, pull in non-linear data from user space
* for *msg* and set pointers *msg*\ **->data** and *msg*\
* **->data_end** to *start* and *end* bytes offsets into *msg*,
* respectively.
*
* If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
* *msg* it can only parse data that the (**data**, **data_end**)
* pointers have already consumed. For **sendmsg**\ () hooks this
* is likely the first scatterlist element. But for calls relying
* on the **sendpage** handler (e.g. **sendfile**\ ()) this will
* be the range (**0**, **0**) because the data is shared with
* user space and by default the objective is to avoid allowing
* user space to modify data while (or after) eBPF verdict is
* being decided. This helper can be used to pull in data and to
* set the start and end pointer to given values. Data will be
* copied if necessary (i.e. if data was not linear and if start
* and end pointers do not point to the same chunk).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
* Description
* Bind the socket associated to *ctx* to the address pointed by
* *addr*, of length *addr_len*. This allows for making outgoing
* connection from the desired IP address, which can be useful for
* example when all processes inside a cgroup should use one
* single IP address on a host that has multiple IP configured.
*
* This helper works for IPv4 and IPv6, TCP and UDP sockets. The
* domain (*addr*\ **->sa_family**) must be **AF_INET** (or
* **AF_INET6**). Looking for a free port to bind to can be
* expensive, therefore binding to port is not permitted by the
* helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
* must be set to zero.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
* only possible to shrink the packet as of this writing,
* therefore *delta* must be a negative integer.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
* Description
* Retrieve the XFRM state (IP transform framework, see also
* **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
*
* The retrieved value is stored in the **struct bpf_xfrm_state**
* pointed by *xfrm_state* and of length *size*.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_XFRM** configuration option.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
* Description
* Return a user or a kernel stack in bpf program provided buffer.
* To achieve this, the helper needs *ctx*, which is a pointer
* to the context on which the tracing program is executed.
* To store the stacktrace, the bpf program provides *buf* with
* a nonnegative *size*.
*
* The last argument, *flags*, holds the number of stack frames to
* skip (from 0 to 255), masked with
* **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
* the following flags:
*
* **BPF_F_USER_STACK**
* Collect a user space stack instead of a kernel stack.
* **BPF_F_USER_BUILD_ID**
* Collect buildid+offset instead of ips for user stack,
* only valid if **BPF_F_USER_STACK** is also specified.
*
* **bpf_get_stack**\ () can collect up to
* **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
* to sufficient large buffer size. Note that
* this limit can be controlled with the **sysctl** program, and
* that it should be manually increased in order to profile long
* user stacks (such as stacks for Java programs). To do so, use:
*
* ::
*
* # sysctl kernel.perf_event_max_stack=<new value>
* Return
* A non-negative value equal to or less than *size* on success,
* or a negative error in case of failure.
*
* int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
* Description
* This helper is similar to **bpf_skb_load_bytes**\ () in that
* it provides an easy way to load *len* bytes from *offset*
* from the packet associated to *skb*, into the buffer pointed
* by *to*. The difference to **bpf_skb_load_bytes**\ () is that
* a fifth argument *start_header* exists in order to select a
* base offset to start from. *start_header* can be one of:
*
* **BPF_HDR_START_MAC**
* Base offset to load data from is *skb*'s mac header.
* **BPF_HDR_START_NET**
* Base offset to load data from is *skb*'s network header.
*
* In general, "direct packet access" is the preferred method to
* access packet data, however, this helper is in particular useful
* in socket filters where *skb*\ **->data** does not always point
* to the start of the mac header and where "direct packet access"
* is not available.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
* Description
* Do FIB lookup in kernel tables using parameters in *params*.
* If lookup is successful and result shows packet is to be
* forwarded, the neighbor tables are searched for the nexthop.
* If successful (ie., FIB lookup shows forwarding and nexthop
* is resolved), the nexthop address is returned in ipv4_dst
* or ipv6_dst based on family, smac is set to mac address of
* egress device, dmac is set to nexthop mac address, rt_metric
* is set to metric from route (IPv4/IPv6 only), and ifindex
* is set to the device index of the nexthop from the FIB lookup.
*
* *plen* argument is the size of the passed in struct.
* *flags* argument can be a combination of one or more of the
* following values:
*
* **BPF_FIB_LOOKUP_DIRECT**
* Do a direct table lookup vs full lookup using FIB
* rules.
* **BPF_FIB_LOOKUP_OUTPUT**
* Perform lookup from an egress perspective (default is
* ingress).
*
* *ctx* is either **struct xdp_md** for XDP programs or
* **struct sk_buff** tc cls_act programs.
* Return
* * < 0 if any input argument is invalid
* * 0 on success (packet is forwarded, nexthop neighbor exists)
* * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
* packet is not forwarded or needs assist from full stack
*
* int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
* Description
* Add an entry to, or update a sockhash *map* referencing sockets.
* The *skops* is used as a new value for the entry associated to
* *key*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* If the *map* has eBPF programs (parser and verdict), those will
* be inherited by the socket being added. If the socket is
* already attached to eBPF programs, this results in an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* socket level. If the message *msg* is allowed to pass (i.e. if
* the verdict eBPF program returns **SK_PASS**), redirect it to
* the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
* if the verdeict eBPF program returns **SK_PASS**), redirect it
* to the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
* Description
* Encapsulate the packet associated to *skb* within a Layer 3
* protocol header. This header is provided in the buffer at
* address *hdr*, with *len* its size in bytes. *type* indicates
* the protocol of the header and can be one of:
*
* **BPF_LWT_ENCAP_SEG6**
* IPv6 encapsulation with Segment Routing Header
* (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
* the IPv6 header is computed by the kernel.
* **BPF_LWT_ENCAP_SEG6_INLINE**
* Only works if *skb* contains an IPv6 packet. Insert a
* Segment Routing Header (**struct ipv6_sr_hdr**) inside
* the IPv6 header.
* **BPF_LWT_ENCAP_IP**
* IP encapsulation (GRE/GUE/IPIP/etc). The outer header
* must be IPv4 or IPv6, followed by zero or more
* additional headers, up to **LWT_BPF_MAX_HEADROOM**
* total bytes in all prepended headers. Please note that
* if **skb_is_gso**\ (*skb*) is true, no more than two
* headers can be prepended, and the inner header, if
* present, should be either GRE or UDP/GUE.
*
* **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
* of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
* be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
* **BPF_PROG_TYPE_LWT_XMIT**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
* Description
* Store *len* bytes from address *from* into the packet
* associated to *skb*, at *offset*. Only the flags, tag and TLVs
* inside the outermost IPv6 Segment Routing Header can be
* modified through this helper.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
* Description
* Adjust the size allocated to TLVs in the outermost IPv6
* Segment Routing Header contained in the packet associated to
* *skb*, at position *offset* by *delta* bytes. Only offsets
* after the segments are accepted. *delta* can be as well
* positive (growing) as negative (shrinking).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
* Description
* Apply an IPv6 Segment Routing action of type *action* to the
* packet associated to *skb*. Each action takes a parameter
* contained at address *param*, and of length *param_len* bytes.
* *action* can be one of:
*
* **SEG6_LOCAL_ACTION_END_X**
* End.X action: Endpoint with Layer-3 cross-connect.
* Type of *param*: **struct in6_addr**.
* **SEG6_LOCAL_ACTION_END_T**
* End.T action: Endpoint with specific IPv6 table lookup.
* Type of *param*: **int**.
* **SEG6_LOCAL_ACTION_END_B6**
* End.B6 action: Endpoint bound to an SRv6 policy.
* Type of *param*: **struct ipv6_sr_hdr**.
* **SEG6_LOCAL_ACTION_END_B6_ENCAP**
* End.B6.Encap action: Endpoint bound to an SRv6
* encapsulation policy.
* Type of *param*: **struct ipv6_sr_hdr**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_rc_repeat(void *ctx)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded repeat key message. This delays
* the generation of a key up event for previously generated
* key down event.
*
* Some IR protocols like NEC have a special IR message for
* repeating last button, for when a button is held down.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded key press with *scancode*,
* *toggle* value in the given *protocol*. The scancode will be
* translated to a keycode using the rc keymap, and reported as
* an input key down event. After a period a key up event is
* generated. This period can be extended by calling either
* **bpf_rc_keydown**\ () again with the same values, or calling
* **bpf_rc_repeat**\ ().
*
* Some protocols include a toggle bit, in case the button was
* released and pressed again between consecutive scancodes.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* The *protocol* is the decoded protocol number (see
* **enum rc_proto** for some predefined values).
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* u64 bpf_skb_cgroup_id(struct sk_buff *skb)
* Description
* Return the cgroup v2 id of the socket associated with the *skb*.
* This is roughly similar to the **bpf_get_cgroup_classid**\ ()
* helper for cgroup v1 by providing a tag resp. identifier that
* can be matched on or used for map lookups e.g. to implement
* policy. The cgroup v2 id of a given path in the hierarchy is
* exposed in user space through the f_handle API in order to get
* to the same 64-bit id.
*
* This helper can be used on TC egress path, but not on ingress,
* and is available only if the kernel was compiled with the
* **CONFIG_SOCK_CGROUP_DATA** configuration option.
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
* u64 bpf_get_current_cgroup_id(void)
* Return
* A 64-bit integer containing the current cgroup id based
* on the cgroup within which the current task is running.
*
* void *bpf_get_local_storage(void *map, u64 flags)
* Description
* Get the pointer to the local storage area.
* The type and the size of the local storage is defined
* by the *map* argument.
* The *flags* meaning is specific for each map type,
* and has to be 0 for cgroup local storage.
*
* Depending on the BPF program type, a local storage area
* can be shared between multiple instances of the BPF program,
* running simultaneously.
*
* A user should care about the synchronization by himself.
* For example, by using the **BPF_STX_XADD** instruction to alter
* the shared data.
* Return
* A pointer to the local storage area.
*
* int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
* Description
* Select a **SO_REUSEPORT** socket from a
* **BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
* It checks the selected socket is matching the incoming
* request in the socket buffer.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
* Description
* Return id of cgroup v2 that is ancestor of cgroup associated
* with the *skb* at the *ancestor_level*. The root cgroup is at
* *ancestor_level* zero and each step down the hierarchy
* increments the level. If *ancestor_level* == level of cgroup
* associated with *skb*, then return value will be same as that
* of **bpf_skb_cgroup_id**\ ().
*
* The helper is useful to implement policies based on cgroups
* that are upper in hierarchy than immediate cgroup associated
* with *skb*.
*
* The format of returned id and helper limitations are same as in
* **bpf_skb_cgroup_id**\ ().
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
* struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* The *ctx* should point to the context of the program, such as
* the skb or socket (depending on the hook in use). This is used
* to determine the base network namespace for the lookup.
*
* *tuple_size* must be one of:
*
* **sizeof**\ (*tuple*\ **->ipv4**)
* Look for an IPv4 socket.
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
* If the *netns* is a negative signed 32-bit integer, then the
* socket lookup table in the netns associated with the *ctx* will
* will be used. For the TC hooks, this is the netns of the device
* in the skb. For socket hooks, this is the netns of the socket.
* If *netns* is any other signed 32-bit value greater than or
* equal to zero then it specifies the ID of the netns relative to
* the netns associated with the *ctx*. *netns* values beyond the
* range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for UDP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* The *ctx* should point to the context of the program, such as
* the skb or socket (depending on the hook in use). This is used
* to determine the base network namespace for the lookup.
*
* *tuple_size* must be one of:
*
* **sizeof**\ (*tuple*\ **->ipv4**)
* Look for an IPv4 socket.
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
* If the *netns* is a negative signed 32-bit integer, then the
* socket lookup table in the netns associated with the *ctx* will
* will be used. For the TC hooks, this is the netns of the device
* in the skb. For socket hooks, this is the netns of the socket.
* If *netns* is any other signed 32-bit value greater than or
* equal to zero then it specifies the ID of the netns relative to
* the netns associated with the *ctx*. *netns* values beyond the
* range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* int bpf_sk_release(struct bpf_sock *sock)
* Description
* Release the reference held by *sock*. *sock* must be a
* non-**NULL** pointer that was returned from
* **bpf_sk_lookup_xxx**\ ().
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
* Description
* Push an element *value* in *map*. *flags* is one of:
*
* **BPF_EXIST**
* If the queue/stack is full, the oldest element is
* removed to make room for this.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_map_pop_elem(struct bpf_map *map, void *value)
* Description
* Pop an element from *map*.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_map_peek_elem(struct bpf_map *map, void *value)
* Description
* Get an element from *map* without removing it.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
* Description
* For socket policies, insert *len* bytes into *msg* at offset
* *start*.
*
* If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
* *msg* it may want to insert metadata or options into the *msg*.
* This can later be read and used by any of the lower layer BPF
* hooks.
*
* This helper may fail if under memory pressure (a malloc
* fails) in these cases BPF programs will get an appropriate
* error and BPF programs will need to handle them.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
* Description
* Will remove *pop* bytes from a *msg* starting at byte *start*.
* This may result in **ENOMEM** errors under certain situations if
* an allocation and copy are required due to a full ring buffer.
* However, the helper will try to avoid doing the allocation
* if possible. Other errors can occur if input parameters are
* invalid either due to *start* byte not being valid part of *msg*
* payload and/or *pop* value being to large.
* Return
* 0 on success, or a negative error in case of failure.
*
* int bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded pointer movement.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* int bpf_spin_lock(struct bpf_spin_lock *lock)
* Description
* Acquire a spinlock represented by the pointer *lock*, which is
* stored as part of a value of a map. Taking the lock allows to
* safely update the rest of the fields in that value. The
* spinlock can (and must) later be released with a call to
* **bpf_spin_unlock**\ (\ *lock*\ ).
*
* Spinlocks in BPF programs come with a number of restrictions
* and constraints:
*
* * **bpf_spin_lock** objects are only allowed inside maps of
* types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
* list could be extended in the future).
* * BTF description of the map is mandatory.
* * The BPF program can take ONE lock at a time, since taking two
* or more could cause dead locks.
* * Only one **struct bpf_spin_lock** is allowed per map element.
* * When the lock is taken, calls (either BPF to BPF or helpers)
* are not allowed.
* * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
* allowed inside a spinlock-ed region.
* * The BPF program MUST call **bpf_spin_unlock**\ () to release
* the lock, on all execution paths, before it returns.
* * The BPF program can access **struct bpf_spin_lock** only via
* the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
* helpers. Loading or storing data into the **struct
* bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
* * To use the **bpf_spin_lock**\ () helper, the BTF description
* of the map value must be a struct and have **struct
* bpf_spin_lock** *anyname*\ **;** field at the top level.
* Nested lock inside another struct is not allowed.
* * The **struct bpf_spin_lock** *lock* field in a map value must
* be aligned on a multiple of 4 bytes in that value.
* * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
* the **bpf_spin_lock** field to user space.
* * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
* a BPF program, do not update the **bpf_spin_lock** field.
* * **bpf_spin_lock** cannot be on the stack or inside a
* networking packet (it can only be inside of a map values).
* * **bpf_spin_lock** is available to root only.
* * Tracing programs and socket filter programs cannot use
* **bpf_spin_lock**\ () due to insufficient preemption checks
* (but this may change in the future).
* * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
* Return
* 0
*
* int bpf_spin_unlock(struct bpf_spin_lock *lock)
* Description
* Release the *lock* previously locked by a call to
* **bpf_spin_lock**\ (\ *lock*\ ).
* Return
* 0
*
* struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_sock** pointer such
* that all the fields in this **bpf_sock** can be accessed.
* Return
* A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_tcp_sock** pointer from a
* **struct bpf_sock** pointer.
* Return
* A **struct bpf_tcp_sock** pointer on success, or **NULL** in
* case of failure.
*
* int bpf_skb_ecn_set_ce(struct sk_buf *skb)
* Description
* Set ECN (Explicit Congestion Notification) field of IP header
* to **CE** (Congestion Encountered) if current value is **ECT**
* (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
* and IPv4.
* Return
* 1 if the **CE** flag is set (either by the current helper call
* or because it was already present), 0 if it is not set.
*
* struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
* Description
* Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
* **bpf_sk_release**\ () is unnecessary and not allowed.
* Return
* A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* This function is identical to **bpf_sk_lookup_tcp**\ (), except
* that it also returns timewait or request sockets. Use
* **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
* full structure.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* int bpf_tcp_check_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
* Description
* Check whether *iph* and *th* contain a valid SYN cookie ACK for
* the listening socket in *sk*.
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
* **sizeof**\ (**struct ip6hdr**).
*
* *th* points to the start of the TCP header, while *th_len*
* contains **sizeof**\ (**struct tcphdr**).
*
* Return
* 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
* error otherwise.
*
* int bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
* Description
* Get name of sysctl in /proc/sys/ and copy it into provided by
* program buffer *buf* of size *buf_len*.
*
* The buffer is always NUL terminated, unless it's zero-sized.
*
* If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
* copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
* only (e.g. "tcp_mem").
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* int bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
* Description
* Get current value of sysctl as it is presented in /proc/sys
* (incl. newline, etc), and copy it as a string into provided
* by program buffer *buf* of size *buf_len*.
*
* The whole value is copied, no matter what file position user
* space issued e.g. sys_read at.
*
* The buffer is always NUL terminated, unless it's zero-sized.
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* **-EINVAL** if current value was unavailable, e.g. because
* sysctl is uninitialized and read returns -EIO for it.
*
* int bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
* Description
* Get new value being written by user space to sysctl (before
* the actual write happens) and copy it as a string into
* provided by program buffer *buf* of size *buf_len*.
*
* User space may write new value at file position > 0.
*
* The buffer is always NUL terminated, unless it's zero-sized.
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* **-EINVAL** if sysctl is being read.
*
* int bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
* Description
* Override new value being written by user space to sysctl with
* value provided by program in buffer *buf* of size *buf_len*.
*
* *buf* should contain a string in same form as provided by user
* space on sysctl write.
*
* User space may write new value at file position > 0. To override
* the whole sysctl value file position should be set to zero.
* Return
* 0 on success.
*
* **-E2BIG** if the *buf_len* is too big.
*
* **-EINVAL** if sysctl is being read.
*
* int bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
* Description
* Convert the initial part of the string from buffer *buf* of
* size *buf_len* to a long integer according to the given base
* and save the result in *res*.
*
* The string may begin with an arbitrary amount of white space
* (as determined by **isspace**\ (3)) followed by a single
* optional '**-**' sign.
*
* Five least significant bits of *flags* encode base, other bits
* are currently unused.
*
* Base must be either 8, 10, 16 or 0 to detect it automatically
* similar to user space **strtol**\ (3).
* Return
* Number of characters consumed on success. Must be positive but
* no more than *buf_len*.
*
* **-EINVAL** if no valid digits were found or unsupported base
* was provided.
*
* **-ERANGE** if resulting value was out of range.
*
* int bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
* Description
* Convert the initial part of the string from buffer *buf* of
* size *buf_len* to an unsigned long integer according to the
* given base and save the result in *res*.
*
* The string may begin with an arbitrary amount of white space
* (as determined by **isspace**\ (3)).
*
* Five least significant bits of *flags* encode base, other bits
* are currently unused.
*
* Base must be either 8, 10, 16 or 0 to detect it automatically
* similar to user space **strtoul**\ (3).
* Return
* Number of characters consumed on success. Must be positive but
* no more than *buf_len*.
*
* **-EINVAL** if no valid digits were found or unsupported base
* was provided.
*
* **-ERANGE** if resulting value was out of range.
*
* void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags)
* Description
* Get a bpf-local-storage from a *sk*.
*
* Logically, it could be thought of getting the value from
* a *map* with *sk* as the **key**. From this
* perspective, the usage is not much different from
* **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
* helper enforces the key must be a full socket and the map must
* be a **BPF_MAP_TYPE_SK_STORAGE** also.
*
* Underneath, the value is stored locally at *sk* instead of
* the *map*. The *map* is used as the bpf-local-storage
* "type". The bpf-local-storage "type" (i.e. the *map*) is
* searched against all bpf-local-storages residing at *sk*.
*
* An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
* used such that a new bpf-local-storage will be
* created if one does not exist. *value* can be used
* together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
* the initial value of a bpf-local-storage. If *value* is
* **NULL**, the new bpf-local-storage will be zero initialized.
* Return
* A bpf-local-storage pointer is returned on success.
*
* **NULL** if not found or there was an error in adding
* a new bpf-local-storage.
*
* int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk)
* Description
* Delete a bpf-local-storage from a *sk*.
* Return
* 0 on success.
*
* **-ENOENT** if the bpf-local-storage cannot be found.
*
* int bpf_send_signal(u32 sig)
* Description
* Send signal *sig* to the current task.
* Return
* 0 on success or successfully queued.
*
* **-EBUSY** if work queue under nmi is full.
*
* **-EINVAL** if *sig* is invalid.
*
* **-EPERM** if no permission to send the *sig*.
*
* **-EAGAIN** if bpf program can try again.
*
* s64 bpf_tcp_gen_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
* Description
* Try to issue a SYN cookie for the packet with corresponding
* IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
* **sizeof**\ (**struct ip6hdr**).
*
* *th* points to the start of the TCP header, while *th_len*
* contains the length of the TCP header.
*
* Return
* On success, lower 32 bits hold the generated SYN cookie in
* followed by 16 bits which hold the MSS value for that cookie,
* and the top 16 bits are unused.
*
* On failure, the returned value is one of the following:
*
* **-EINVAL** SYN cookie cannot be issued due to error
*
* **-ENOENT** SYN cookie should not be issued (no SYN flood)
*
* **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
*
* **-EPROTONOSUPPORT** IP packet version is not 4 or 6
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
FN(map_lookup_elem), \
FN(map_update_elem), \
FN(map_delete_elem), \
FN(probe_read), \
FN(ktime_get_ns), \
FN(trace_printk), \
FN(get_prandom_u32), \
FN(get_smp_processor_id), \
FN(skb_store_bytes), \
FN(l3_csum_replace), \
FN(l4_csum_replace), \
FN(tail_call), \
FN(clone_redirect), \
FN(get_current_pid_tgid), \
FN(get_current_uid_gid), \
FN(get_current_comm), \
FN(get_cgroup_classid), \
FN(skb_vlan_push), \
FN(skb_vlan_pop), \
FN(skb_get_tunnel_key), \
FN(skb_set_tunnel_key), \
FN(perf_event_read), \
FN(redirect), \
FN(get_route_realm), \
FN(perf_event_output), \
FN(skb_load_bytes), \
FN(get_stackid), \
FN(csum_diff), \
FN(skb_get_tunnel_opt), \
FN(skb_set_tunnel_opt), \
FN(skb_change_proto), \
FN(skb_change_type), \
FN(skb_under_cgroup), \
FN(get_hash_recalc), \
FN(get_current_task), \
FN(probe_write_user), \
FN(current_task_under_cgroup), \
FN(skb_change_tail), \
FN(skb_pull_data), \
FN(csum_update), \
FN(set_hash_invalid), \
FN(get_numa_node_id), \
FN(skb_change_head), \
FN(xdp_adjust_head), \
FN(probe_read_str), \
FN(get_socket_cookie), \
FN(get_socket_uid), \
FN(set_hash), \
FN(setsockopt), \
FN(skb_adjust_room), \
FN(redirect_map), \
FN(sk_redirect_map), \
FN(sock_map_update), \
FN(xdp_adjust_meta), \
FN(perf_event_read_value), \
FN(perf_prog_read_value), \
FN(getsockopt), \
FN(override_return), \
FN(sock_ops_cb_flags_set), \
FN(msg_redirect_map), \
FN(msg_apply_bytes), \
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
FN(xdp_adjust_tail), \
FN(skb_get_xfrm_state), \
FN(get_stack), \
FN(skb_load_bytes_relative), \
FN(fib_lookup), \
FN(sock_hash_update), \
FN(msg_redirect_hash), \
FN(sk_redirect_hash), \
FN(lwt_push_encap), \
FN(lwt_seg6_store_bytes), \
FN(lwt_seg6_adjust_srh), \
FN(lwt_seg6_action), \
FN(rc_repeat), \
FN(rc_keydown), \
FN(skb_cgroup_id), \
FN(get_current_cgroup_id), \
FN(get_local_storage), \
FN(sk_select_reuseport), \
FN(skb_ancestor_cgroup_id), \
FN(sk_lookup_tcp), \
FN(sk_lookup_udp), \
FN(sk_release), \
FN(map_push_elem), \
FN(map_pop_elem), \
FN(map_peek_elem), \
FN(msg_push_data), \
FN(msg_pop_data), \
FN(rc_pointer_rel), \
FN(spin_lock), \
FN(spin_unlock), \
FN(sk_fullsock), \
FN(tcp_sock), \
FN(skb_ecn_set_ce), \
FN(get_listener_sock), \
FN(skc_lookup_tcp), \
FN(tcp_check_syncookie), \
FN(sysctl_get_name), \
FN(sysctl_get_current_value), \
FN(sysctl_get_new_value), \
FN(sysctl_set_new_value), \
FN(strtol), \
FN(strtoul), \
FN(sk_storage_get), \
FN(sk_storage_delete), \
FN(send_signal), \
FN(tcp_gen_syncookie),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
*/
#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
enum bpf_func_id {
__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
__BPF_FUNC_MAX_ID,
};
#undef __BPF_ENUM_FN
/* All flags used by eBPF helper functions, placed here. */
/* BPF_FUNC_skb_store_bytes flags. */
#define BPF_F_RECOMPUTE_CSUM (1ULL << 0)
#define BPF_F_INVALIDATE_HASH (1ULL << 1)
/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
* First 4 bits are for passing the header field size.
*/
#define BPF_F_HDR_FIELD_MASK 0xfULL
/* BPF_FUNC_l4_csum_replace flags. */
#define BPF_F_PSEUDO_HDR (1ULL << 4)
#define BPF_F_MARK_MANGLED_0 (1ULL << 5)
#define BPF_F_MARK_ENFORCE (1ULL << 6)
/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
#define BPF_F_INGRESS (1ULL << 0)
/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
#define BPF_F_TUNINFO_IPV6 (1ULL << 0)
/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
#define BPF_F_SKIP_FIELD_MASK 0xffULL
#define BPF_F_USER_STACK (1ULL << 8)
/* flags used by BPF_FUNC_get_stackid only. */
#define BPF_F_FAST_STACK_CMP (1ULL << 9)
#define BPF_F_REUSE_STACKID (1ULL << 10)
/* flags used by BPF_FUNC_get_stack only. */
#define BPF_F_USER_BUILD_ID (1ULL << 11)
/* BPF_FUNC_skb_set_tunnel_key flags. */
#define BPF_F_ZERO_CSUM_TX (1ULL << 1)
#define BPF_F_DONT_FRAGMENT (1ULL << 2)
#define BPF_F_SEQ_NUMBER (1ULL << 3)
/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
* BPF_FUNC_perf_event_read_value flags.
*/
#define BPF_F_INDEX_MASK 0xffffffffULL
#define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK
/* BPF_FUNC_perf_event_output for sk_buff input context. */
#define BPF_F_CTXLEN_MASK (0xfffffULL << 32)
/* Current network namespace */
#define BPF_F_CURRENT_NETNS (-1L)
/* BPF_FUNC_skb_adjust_room flags. */
#define BPF_F_ADJ_ROOM_FIXED_GSO (1ULL << 0)
#define BPF_ADJ_ROOM_ENCAP_L2_MASK 0xff
#define BPF_ADJ_ROOM_ENCAP_L2_SHIFT 56
#define BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 (1ULL << 1)
#define BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 (1ULL << 2)
#define BPF_F_ADJ_ROOM_ENCAP_L4_GRE (1ULL << 3)
#define BPF_F_ADJ_ROOM_ENCAP_L4_UDP (1ULL << 4)
#define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \
BPF_ADJ_ROOM_ENCAP_L2_MASK) \
<< BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
/* BPF_FUNC_sysctl_get_name flags. */
#define BPF_F_SYSCTL_BASE_NAME (1ULL << 0)
/* BPF_FUNC_sk_storage_get flags */
#define BPF_SK_STORAGE_GET_F_CREATE (1ULL << 0)
/* Mode for BPF_FUNC_skb_adjust_room helper. */
enum bpf_adj_room_mode {
BPF_ADJ_ROOM_NET,
BPF_ADJ_ROOM_MAC,
};
/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
enum bpf_hdr_start_off {
BPF_HDR_START_MAC,
BPF_HDR_START_NET,
};
/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
enum bpf_lwt_encap_mode {
BPF_LWT_ENCAP_SEG6,
BPF_LWT_ENCAP_SEG6_INLINE,
BPF_LWT_ENCAP_IP,
};
#define __bpf_md_ptr(type, name) \
union { \
type name; \
__u64 :64; \
} __attribute__((aligned(8)))
/* user accessible mirror of in-kernel sk_buff.
* new fields can only be added to the end of this structure
*/
struct __sk_buff {
__u32 len;
__u32 pkt_type;
__u32 mark;
__u32 queue_mapping;
__u32 protocol;
__u32 vlan_present;
__u32 vlan_tci;
__u32 vlan_proto;
__u32 priority;
__u32 ingress_ifindex;
__u32 ifindex;
__u32 tc_index;
__u32 cb[5];
__u32 hash;
__u32 tc_classid;
__u32 data;
__u32 data_end;
__u32 napi_id;
/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
__u32 family;
__u32 remote_ip4; /* Stored in network byte order */
__u32 local_ip4; /* Stored in network byte order */
__u32 remote_ip6[4]; /* Stored in network byte order */
__u32 local_ip6[4]; /* Stored in network byte order */
__u32 remote_port; /* Stored in network byte order */
__u32 local_port; /* stored in host byte order */
/* ... here. */
__u32 data_meta;
__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
__u64 tstamp;
__u32 wire_len;
__u32 gso_segs;
__bpf_md_ptr(struct bpf_sock *, sk);
};
struct bpf_tunnel_key {
__u32 tunnel_id;
union {
__u32 remote_ipv4;
__u32 remote_ipv6[4];
};
__u8 tunnel_tos;
__u8 tunnel_ttl;
__u16 tunnel_ext; /* Padding, future use. */
__u32 tunnel_label;
};
/* user accessible mirror of in-kernel xfrm_state.
* new fields can only be added to the end of this structure
*/
struct bpf_xfrm_state {
__u32 reqid;
__u32 spi; /* Stored in network byte order */
__u16 family;
__u16 ext; /* Padding, future use. */
union {
__u32 remote_ipv4; /* Stored in network byte order */
__u32 remote_ipv6[4]; /* Stored in network byte order */
};
};
/* Generic BPF return codes which all BPF program types may support.
* The values are binary compatible with their TC_ACT_* counter-part to
* provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
* programs.
*
* XDP is handled seprately, see XDP_*.
*/
enum bpf_ret_code {
BPF_OK = 0,
/* 1 reserved */
BPF_DROP = 2,
/* 3-6 reserved */
BPF_REDIRECT = 7,
/* >127 are reserved for prog type specific return codes.
*
* BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
* BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
* changed and should be routed based on its new L3 header.
* (This is an L3 redirect, as opposed to L2 redirect
* represented by BPF_REDIRECT above).
*/
BPF_LWT_REROUTE = 128,
};
struct bpf_sock {
__u32 bound_dev_if;
__u32 family;
__u32 type;
__u32 protocol;
__u32 mark;
__u32 priority;
/* IP address also allows 1 and 2 bytes access */
__u32 src_ip4;
__u32 src_ip6[4];
__u32 src_port; /* host byte order */
__be16 dst_port; /* network byte order */
__u16 :16; /* zero padding */
__u32 dst_ip4;
__u32 dst_ip6[4];
__u32 state;
};
struct bpf_tcp_sock {
__u32 snd_cwnd; /* Sending congestion window */
__u32 srtt_us; /* smoothed round trip time << 3 in usecs */
__u32 rtt_min;
__u32 snd_ssthresh; /* Slow start size threshold */
__u32 rcv_nxt; /* What we want to receive next */
__u32 snd_nxt; /* Next sequence we send */
__u32 snd_una; /* First byte we want an ack for */
__u32 mss_cache; /* Cached effective mss, not including SACKS */
__u32 ecn_flags; /* ECN status bits. */
__u32 rate_delivered; /* saved rate sample: packets delivered */
__u32 rate_interval_us; /* saved rate sample: time elapsed */
__u32 packets_out; /* Packets which are "in flight" */
__u32 retrans_out; /* Retransmitted packets out */
__u32 total_retrans; /* Total retransmits for entire connection */
__u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
* total number of segments in.
*/
__u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
* total number of data segments in.
*/
__u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
* The total number of segments sent.
*/
__u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
* total number of data segments sent.
*/
__u32 lost_out; /* Lost packets */
__u32 sacked_out; /* SACK'd packets */
__u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
* sum(delta(rcv_nxt)), or how many bytes
* were acked.
*/
__u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
* sum(delta(snd_una)), or how many bytes
* were acked.
*/
__u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
* total number of DSACK blocks received
*/
__u32 delivered; /* Total data packets delivered incl. rexmits */
__u32 delivered_ce; /* Like the above but only ECE marked packets */
__u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
};
struct bpf_sock_tuple {
union {
struct {
__be32 saddr;
__be32 daddr;
__be16 sport;
__be16 dport;
} ipv4;
struct {
__be32 saddr[4];
__be32 daddr[4];
__be16 sport;
__be16 dport;
} ipv6;
};
};
struct bpf_xdp_sock {
__u32 queue_id;
};
#define XDP_PACKET_HEADROOM 256
/* User return codes for XDP prog type.
* A valid XDP program must return one of these defined values. All other
* return codes are reserved for future use. Unknown return codes will
* result in packet drops and a warning via bpf_warn_invalid_xdp_action().
*/
enum xdp_action {
XDP_ABORTED = 0,
XDP_DROP,
XDP_PASS,
XDP_TX,
XDP_REDIRECT,
};
/* user accessible metadata for XDP packet hook
* new fields must be added to the end of this structure
*/
struct xdp_md {
__u32 data;
__u32 data_end;
__u32 data_meta;
/* Below access go through struct xdp_rxq_info */
__u32 ingress_ifindex; /* rxq->dev->ifindex */
__u32 rx_queue_index; /* rxq->queue_index */
};
enum sk_action {
SK_DROP = 0,
SK_PASS,
};
/* user accessible metadata for SK_MSG packet hook, new fields must
* be added to the end of this structure
*/
struct sk_msg_md {
__bpf_md_ptr(void *, data);
__bpf_md_ptr(void *, data_end);
__u32 family;
__u32 remote_ip4; /* Stored in network byte order */
__u32 local_ip4; /* Stored in network byte order */
__u32 remote_ip6[4]; /* Stored in network byte order */
__u32 local_ip6[4]; /* Stored in network byte order */
__u32 remote_port; /* Stored in network byte order */
__u32 local_port; /* stored in host byte order */
__u32 size; /* Total size of sk_msg */
};
struct sk_reuseport_md {
/*
* Start of directly accessible data. It begins from
* the tcp/udp header.
*/
__bpf_md_ptr(void *, data);
/* End of directly accessible data */
__bpf_md_ptr(void *, data_end);
/*
* Total length of packet (starting from the tcp/udp header).
* Note that the directly accessible bytes (data_end - data)
* could be less than this "len". Those bytes could be
* indirectly read by a helper "bpf_skb_load_bytes()".
*/
__u32 len;
/*
* Eth protocol in the mac header (network byte order). e.g.
* ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
*/
__u32 eth_protocol;
__u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
__u32 bind_inany; /* Is sock bound to an INANY address? */
__u32 hash; /* A hash of the packet 4 tuples */
};
#define BPF_TAG_SIZE 8
struct bpf_prog_info {
__u32 type;
__u32 id;
__u8 tag[BPF_TAG_SIZE];
__u32 jited_prog_len;
__u32 xlated_prog_len;
__aligned_u64 jited_prog_insns;
__aligned_u64 xlated_prog_insns;
__u64 load_time; /* ns since boottime */
__u32 created_by_uid;
__u32 nr_map_ids;
__aligned_u64 map_ids;
char name[BPF_OBJ_NAME_LEN];
__u32 ifindex;
__u32 gpl_compatible:1;
__u32 :31; /* alignment pad */
__u64 netns_dev;
__u64 netns_ino;
__u32 nr_jited_ksyms;
__u32 nr_jited_func_lens;
__aligned_u64 jited_ksyms;
__aligned_u64 jited_func_lens;
__u32 btf_id;
__u32 func_info_rec_size;
__aligned_u64 func_info;
__u32 nr_func_info;
__u32 nr_line_info;
__aligned_u64 line_info;
__aligned_u64 jited_line_info;
__u32 nr_jited_line_info;
__u32 line_info_rec_size;
__u32 jited_line_info_rec_size;
__u32 nr_prog_tags;
__aligned_u64 prog_tags;
__u64 run_time_ns;
__u64 run_cnt;
} __attribute__((aligned(8)));
struct bpf_map_info {
__u32 type;
__u32 id;
__u32 key_size;
__u32 value_size;
__u32 max_entries;
__u32 map_flags;
char name[BPF_OBJ_NAME_LEN];
__u32 ifindex;
__u32 :32;
__u64 netns_dev;
__u64 netns_ino;
__u32 btf_id;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
} __attribute__((aligned(8)));
struct bpf_btf_info {
__aligned_u64 btf;
__u32 btf_size;
__u32 id;
} __attribute__((aligned(8)));
/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
* by user and intended to be used by socket (e.g. to bind to, depends on
* attach attach type).
*/
struct bpf_sock_addr {
__u32 user_family; /* Allows 4-byte read, but no write. */
__u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
* Stored in network byte order.
*/
__u32 user_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
* Stored in network byte order.
*/
__u32 user_port; /* Allows 4-byte read and write.
* Stored in network byte order
*/
__u32 family; /* Allows 4-byte read, but no write */
__u32 type; /* Allows 4-byte read, but no write */
__u32 protocol; /* Allows 4-byte read, but no write */
__u32 msg_src_ip4; /* Allows 1,2,4-byte read and 4-byte write.
* Stored in network byte order.
*/
__u32 msg_src_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
* Stored in network byte order.
*/
__bpf_md_ptr(struct bpf_sock *, sk);
};
/* User bpf_sock_ops struct to access socket values and specify request ops
* and their replies.
* Some of this fields are in network (bigendian) byte order and may need
* to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
* New fields can only be added at the end of this structure
*/
struct bpf_sock_ops {
__u32 op;
union {
__u32 args[4]; /* Optionally passed to bpf program */
__u32 reply; /* Returned by bpf program */
__u32 replylong[4]; /* Optionally returned by bpf prog */
};
__u32 family;
__u32 remote_ip4; /* Stored in network byte order */
__u32 local_ip4; /* Stored in network byte order */
__u32 remote_ip6[4]; /* Stored in network byte order */
__u32 local_ip6[4]; /* Stored in network byte order */
__u32 remote_port; /* Stored in network byte order */
__u32 local_port; /* stored in host byte order */
__u32 is_fullsock; /* Some TCP fields are only valid if
* there is a full socket. If not, the
* fields read as zero.
*/
__u32 snd_cwnd;
__u32 srtt_us; /* Averaged RTT << 3 in usecs */
__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
__u32 state;
__u32 rtt_min;
__u32 snd_ssthresh;
__u32 rcv_nxt;
__u32 snd_nxt;
__u32 snd_una;
__u32 mss_cache;
__u32 ecn_flags;
__u32 rate_delivered;
__u32 rate_interval_us;
__u32 packets_out;
__u32 retrans_out;
__u32 total_retrans;
__u32 segs_in;
__u32 data_segs_in;
__u32 segs_out;
__u32 data_segs_out;
__u32 lost_out;
__u32 sacked_out;
__u32 sk_txhash;
__u64 bytes_received;
__u64 bytes_acked;
__bpf_md_ptr(struct bpf_sock *, sk);
};
/* Definitions for bpf_sock_ops_cb_flags */
#define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
#define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1)
#define BPF_SOCK_OPS_STATE_CB_FLAG (1<<2)
#define BPF_SOCK_OPS_RTT_CB_FLAG (1<<3)
#define BPF_SOCK_OPS_ALL_CB_FLAGS 0xF /* Mask of all currently
* supported cb flags
*/
/* List of known BPF sock_ops operators.
* New entries can only be added at the end
*/
enum {
BPF_SOCK_OPS_VOID,
BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
* -1 if default value should be used
*/
BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
* window (in packets) or -1 if default
* value should be used
*/
BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
* active connection is initialized
*/
BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
* active connection is
* established
*/
BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
* passive connection is
* established
*/
BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
* needs ECN
*/
BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
* based on the path and may be
* dependent on the congestion control
* algorithm. In general it indicates
* a congestion threshold. RTTs above
* this indicate congestion
*/
BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
* Arg1: value of icsk_retransmits
* Arg2: value of icsk_rto
* Arg3: whether RTO has expired
*/
BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
* Arg1: sequence number of 1st byte
* Arg2: # segments
* Arg3: return value of
* tcp_transmit_skb (0 => success)
*/
BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
* Arg1: old_state
* Arg2: new_state
*/
BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
* socket transition to LISTEN state.
*/
BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
*/
};
/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
* changes between the TCP and BPF versions. Ideally this should never happen.
* If it does, we need to add code to convert them before calling
* the BPF sock_ops function.
*/
enum {
BPF_TCP_ESTABLISHED = 1,
BPF_TCP_SYN_SENT,
BPF_TCP_SYN_RECV,
BPF_TCP_FIN_WAIT1,
BPF_TCP_FIN_WAIT2,
BPF_TCP_TIME_WAIT,
BPF_TCP_CLOSE,
BPF_TCP_CLOSE_WAIT,
BPF_TCP_LAST_ACK,
BPF_TCP_LISTEN,
BPF_TCP_CLOSING, /* Now a valid state */
BPF_TCP_NEW_SYN_RECV,
BPF_TCP_MAX_STATES /* Leave at the end! */
};
#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
#define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */
struct bpf_perf_event_value {
__u64 counter;
__u64 enabled;
__u64 running;
};
#define BPF_DEVCG_ACC_MKNOD (1ULL << 0)
#define BPF_DEVCG_ACC_READ (1ULL << 1)
#define BPF_DEVCG_ACC_WRITE (1ULL << 2)
#define BPF_DEVCG_DEV_BLOCK (1ULL << 0)
#define BPF_DEVCG_DEV_CHAR (1ULL << 1)
struct bpf_cgroup_dev_ctx {
/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
__u32 access_type;
__u32 major;
__u32 minor;
};
struct bpf_raw_tracepoint_args {
__u64 args[0];
};
/* DIRECT: Skip the FIB rules and go to FIB table associated with device
* OUTPUT: Do lookup from egress perspective; default is ingress
*/
#define BPF_FIB_LOOKUP_DIRECT (1U << 0)
#define BPF_FIB_LOOKUP_OUTPUT (1U << 1)
enum {
BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
};
struct bpf_fib_lookup {
/* input: network family for lookup (AF_INET, AF_INET6)
* output: network family of egress nexthop
*/
__u8 family;
/* set if lookup is to consider L4 data - e.g., FIB rules */
__u8 l4_protocol;
__be16 sport;
__be16 dport;
/* total length of packet from network header - used for MTU check */
__u16 tot_len;
/* input: L3 device index for lookup
* output: device index from FIB lookup
*/
__u32 ifindex;
union {
/* inputs to lookup */
__u8 tos; /* AF_INET */
__be32 flowinfo; /* AF_INET6, flow_label + priority */
/* output: metric of fib result (IPv4/IPv6 only) */
__u32 rt_metric;
};
union {
__be32 ipv4_src;
__u32 ipv6_src[4]; /* in6_addr; network order */
};
/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
* network header. output: bpf_fib_lookup sets to gateway address
* if FIB lookup returns gateway route
*/
union {
__be32 ipv4_dst;
__u32 ipv6_dst[4]; /* in6_addr; network order */
};
/* output */
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
__u8 smac[6]; /* ETH_ALEN */
__u8 dmac[6]; /* ETH_ALEN */
};
enum bpf_task_fd_type {
BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
BPF_FD_TYPE_TRACEPOINT, /* tp name */
BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
BPF_FD_TYPE_UPROBE, /* filename + offset */
BPF_FD_TYPE_URETPROBE, /* filename + offset */
};
#define BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG (1U << 0)
#define BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL (1U << 1)
#define BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP (1U << 2)
struct bpf_flow_keys {
__u16 nhoff;
__u16 thoff;
__u16 addr_proto; /* ETH_P_* of valid addrs */
__u8 is_frag;
__u8 is_first_frag;
__u8 is_encap;
__u8 ip_proto;
__be16 n_proto;
__be16 sport;
__be16 dport;
union {
struct {
__be32 ipv4_src;
__be32 ipv4_dst;
};
struct {
__u32 ipv6_src[4]; /* in6_addr; network order */
__u32 ipv6_dst[4]; /* in6_addr; network order */
};
};
__u32 flags;
__be32 flow_label;
};
struct bpf_func_info {
__u32 insn_off;
__u32 type_id;
};
#define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
#define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
struct bpf_line_info {
__u32 insn_off;
__u32 file_name_off;
__u32 line_off;
__u32 line_col;
};
struct bpf_spin_lock {
__u32 val;
};
struct bpf_sysctl {
__u32 write; /* Sysctl is being read (= 0) or written (= 1).
* Allows 1,2,4-byte read, but no write.
*/
__u32 file_pos; /* Sysctl file position to read from, write to.
* Allows 1,2,4-byte read an 4-byte write.
*/
};
struct bpf_sockopt {
__bpf_md_ptr(struct bpf_sock *, sk);
__bpf_md_ptr(void *, optval);
__bpf_md_ptr(void *, optval_end);
__s32 level;
__s32 optname;
__s32 optlen;
__s32 retval;
};
#endif /* __LINUX_BPF_H__ */
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