Re: [Qemu-devel] [RFC 1/1] Add BPF support to qemu

[Murilo Opsfelder Araujo <muriloo@linux.ibm.com>]

On Tue, Jun 19, 2018 at 04:22:00PM +0300, Sameeh Jubran wrote:
> From: Sameeh Jubran <sjubran@redhat.com>
> 
> This commit introduces wrappers around BPF syscalls to qemu. The Berkeley
> Packet Filter (BPF) can be really usefull for packet filtering, tracing and
> monitoring with very minimal overhead.
> 
> Signed-off-by: Sameeh Jubran <sjubran@redhat.com>
> ---
>  MAINTAINERS                     |   7 +
>  bpf/Makefile.objs               |   1 +
>  bpf/bpf_syscall.c               |  98 ++++++
>  include/bpf/bpf_syscall.h       |  35 +++
>  linux-headers/linux/bpf.h       | 673 ++++++++++++++++++++++++++++++++++++++++
>  scripts/update-linux-headers.sh |   3 +-
>  6 files changed, 816 insertions(+), 1 deletion(-)
>  create mode 100644 bpf/Makefile.objs
>  create mode 100644 bpf/bpf_syscall.c
>  create mode 100644 include/bpf/bpf_syscall.h
>  create mode 100644 linux-headers/linux/bpf.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0fb5f38f9f..ce3cd39121 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2126,6 +2126,13 @@ F: hw/rdma/*
>  F: hw/rdma/vmw/*
>  F: docs/pvrdma.txt
>  
> +
> +BPF
> +M: Sameeh Jubran <sameeh@daynix.com>
> +S: Maintained
> +F: bpf/*
> +F: include/bpf*
> +
>  Build and test automation
>  -------------------------
>  Build and test automation
> diff --git a/bpf/Makefile.objs b/bpf/Makefile.objs
> new file mode 100644
> index 0000000000..fc38d9b5c9
> --- /dev/null
> +++ b/bpf/Makefile.objs
> @@ -0,0 +1 @@
> +common-obj-y += bpf_syscall.o

Why do we need to have this enabled by default?

IMO, this should be configurable.  For example, adding a new --enable-bpf to the
./configure script and accessing it via $(CONFIG_BPF) variable in Makefiles.  Or
something among these lines.

> diff --git a/bpf/bpf_syscall.c b/bpf/bpf_syscall.c
> new file mode 100644
> index 0000000000..efdcd57ae8
> --- /dev/null
> +++ b/bpf/bpf_syscall.c
> @@ -0,0 +1,98 @@
> +/*
> + * BPF syscalls
> + *
> + * Based on bpf-syscall.c from iovisor/ply
> + *
> + * Authors:
> + *  Sameeh Jubran <sameeh@daynix.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include <string.h>
> +#include <unistd.h>
> +#include <linux/bpf.h>
> +#include <linux/version.h>
> +#include <sys/syscall.h>
> +
> +#include "bpf/bpf_syscall.h"
> +
> +static __u64 ptr_to_u64(const void *ptr)
> +{
> +        return (__u64) (unsigned long) ptr;
> +}
> +
> +int bpf_prog_load(enum bpf_prog_type type, const struct bpf_insn *insns,
> +                int insn_cnt, const char *license, unsigned kern_version,
> +                int log_level, char *bpf_log_buf, unsigned log_buf_size)
> +{
> +    union bpf_attr attr;
> +
> +    /* required since the kernel checks that unused fields and pad
> +     * bytes are zeroed */
> +    memset(&attr, 0, sizeof(attr));
> +
> +    attr.kern_version = kern_version;
> +    attr.prog_type    = type;
> +    attr.insns        = ptr_to_u64(insns);
> +    attr.insn_cnt     = insn_cnt;
> +    attr.license      = ptr_to_u64(license);
> +    attr.log_buf      = ptr_to_u64(bpf_log_buf);
> +    attr.log_size     = log_buf_size;
> +    attr.log_level    = log_level;
> +
> +    return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
> +}
> +
> +int bpf_map_create(enum bpf_map_type type, int key_size, int val_size,
> +                int entries)
> +{
> +    union bpf_attr attr;
> +
> +    /* required since the kernel checks that unused fields and pad
> +     * bytes are zeroed */
> +    memset(&attr, 0, sizeof(attr));
> +
> +    attr.map_type = type;
> +    attr.key_size = key_size;
> +    attr.value_size = val_size;
> +    attr.max_entries = entries;
> +
> +    return syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));
> +}
> +
> +
> +static int bpf_map_operation(enum bpf_cmd cmd, int fd,
> +              void *key, void *val_or_next, int flags)
> +{
> +    union bpf_attr attr =  {
> +        .map_fd = fd,
> +        .key = ptr_to_u64(key),
> +        .value = ptr_to_u64(val_or_next),
> +        .flags = flags,
> +    };
> +
> +    return syscall(__NR_bpf, cmd, &attr, sizeof(attr));
> +}
> +
> +int bpf_map_lookup(int fd, void *key, void *val)
> +{
> +    return bpf_map_operation(BPF_MAP_LOOKUP_ELEM, fd, key, val, 0);
> +}
> +
> +int bpf_map_update(int fd, void *key, void *val, int flags)
> +{
> +    return bpf_map_operation(BPF_MAP_UPDATE_ELEM, fd, key, val, flags);
> +}
> +
> +int bpf_map_delete(int fd, void *key)
> +{
> +    return bpf_map_operation(BPF_MAP_DELETE_ELEM, fd, key, NULL, 0);
> +}
> +
> +int bpf_map_next(int fd, void *key, void *next_key)
> +{
> +    return bpf_map_operation(BPF_MAP_GET_NEXT_KEY, fd, key, next_key, 0);
> +}
> diff --git a/include/bpf/bpf_syscall.h b/include/bpf/bpf_syscall.h
> new file mode 100644
> index 0000000000..8d1f170343
> --- /dev/null
> +++ b/include/bpf/bpf_syscall.h
> @@ -0,0 +1,35 @@
> +/*
> + * BPF syscalls
> + *
> + * Based on bpf-syscall.h from iovisor/ply
> + *
> + * Authors:
> + *  Sameeh Jubran <sameeh@daynix.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#ifndef BPF_SYSCALL_H
> +#define BPF_SYSCALL_H
> +
> +#include <unistd.h>
> +
> +#include <linux/bpf.h>
> +#include <linux/perf_event.h>
> +#include <linux/version.h>
> +
> +int bpf_prog_load(enum bpf_prog_type type, const struct bpf_insn *insns,
> +                int insn_cnt, const char *license, unsigned kern_version,
> +                int log_level, char *bpf_log_buf, unsigned log_buf_size);
> +
> +int bpf_map_create(enum bpf_map_type type, int key_size, int val_size,
> +                int entries);
> +
> +int bpf_map_lookup(int fd, void *key, void *val);
> +int bpf_map_update(int fd, void *key, void *val, int flags);
> +int bpf_map_delete(int fd, void *key);
> +int bpf_map_next(int fd, void *key, void *next_key);
> +
> +#endif
> diff --git a/linux-headers/linux/bpf.h b/linux-headers/linux/bpf.h
> new file mode 100644
> index 0000000000..d322ca1519
> --- /dev/null
> +++ b/linux-headers/linux/bpf.h
> @@ -0,0 +1,673 @@
> +/* 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_ALU64	0x07	/* alu mode in double word width */
> +
> +/* ld/ldx fields */
> +#define BPF_DW		0x18	/* double word */
> +#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
> +
> +#define BPF_JNE		0x50	/* jump != */
> +#define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
> +#define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
> +#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 */
> +};
> +
> +/* 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,
> +};
> +
> +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,
> +};
> +
> +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,
> +};
> +
> +enum bpf_attach_type {
> +	BPF_CGROUP_INET_INGRESS,
> +	BPF_CGROUP_INET_EGRESS,
> +	BPF_CGROUP_INET_SOCK_CREATE,
> +	__MAX_BPF_ATTACH_TYPE
> +};
> +
> +#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
> +
> +/* If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command
> + * to the given target_fd cgroup the descendent cgroup will be able to
> + * override effective bpf program that was inherited from this cgroup
> + */
> +#define BPF_F_ALLOW_OVERRIDE	(1U << 0)
> +
> +/* 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)
> +
> +#define BPF_PSEUDO_MAP_FD	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_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)
> +
> +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;	/* prealloc or not */
> +		__u32	inner_map_fd;	/* fd pointing to the inner map */
> +	};
> +
> +	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;	/* checked when prog_type=kprobe */
> +		__u32		prog_flags;
> +	};
> +
> +	struct { /* anonymous struct used by BPF_OBJ_* commands */
> +		__aligned_u64	pathname;
> +		__u32		bpf_fd;
> +	};
> +
> +	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;
> +		__u32		data_size_out;
> +		__aligned_u64	data_in;
> +		__aligned_u64	data_out;
> +		__u32		repeat;
> +		__u32		duration;
> +	} test;
> +} __attribute__((aligned(8)));
> +
> +/* BPF helper function descriptions:
> + *
> + * void *bpf_map_lookup_elem(&map, &key)
> + *     Return: Map value or NULL
> + *
> + * int bpf_map_update_elem(&map, &key, &value, flags)
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_map_delete_elem(&map, &key)
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_probe_read(void *dst, int size, void *src)
> + *     Return: 0 on success or negative error
> + *
> + * u64 bpf_ktime_get_ns(void)
> + *     Return: current ktime
> + *
> + * int bpf_trace_printk(const char *fmt, int fmt_size, ...)
> + *     Return: length of buffer written or negative error
> + *
> + * u32 bpf_prandom_u32(void)
> + *     Return: random value
> + *
> + * u32 bpf_raw_smp_processor_id(void)
> + *     Return: SMP processor ID
> + *
> + * int bpf_skb_store_bytes(skb, offset, from, len, flags)
> + *     store bytes into packet
> + *     @skb: pointer to skb
> + *     @offset: offset within packet from skb->mac_header
> + *     @from: pointer where to copy bytes from
> + *     @len: number of bytes to store into packet
> + *     @flags: bit 0 - if true, recompute skb->csum
> + *             other bits - reserved
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_l3_csum_replace(skb, offset, from, to, flags)
> + *     recompute IP checksum
> + *     @skb: pointer to skb
> + *     @offset: offset within packet where IP checksum is located
> + *     @from: old value of header field
> + *     @to: new value of header field
> + *     @flags: bits 0-3 - size of header field
> + *             other bits - reserved
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_l4_csum_replace(skb, offset, from, to, flags)
> + *     recompute TCP/UDP checksum
> + *     @skb: pointer to skb
> + *     @offset: offset within packet where TCP/UDP checksum is located
> + *     @from: old value of header field
> + *     @to: new value of header field
> + *     @flags: bits 0-3 - size of header field
> + *             bit 4 - is pseudo header
> + *             other bits - reserved
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_tail_call(ctx, prog_array_map, index)
> + *     jump into another BPF program
> + *     @ctx: context pointer passed to next program
> + *     @prog_array_map: pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY
> + *     @index: index inside array that selects specific program to run
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_clone_redirect(skb, ifindex, flags)
> + *     redirect to another netdev
> + *     @skb: pointer to skb
> + *     @ifindex: ifindex of the net device
> + *     @flags: bit 0 - if set, redirect to ingress instead of egress
> + *             other bits - reserved
> + *     Return: 0 on success or negative error
> + *
> + * u64 bpf_get_current_pid_tgid(void)
> + *     Return: current->tgid << 32 | current->pid
> + *
> + * u64 bpf_get_current_uid_gid(void)
> + *     Return: current_gid << 32 | current_uid
> + *
> + * int bpf_get_current_comm(char *buf, int size_of_buf)
> + *     stores current->comm into buf
> + *     Return: 0 on success or negative error
> + *
> + * u32 bpf_get_cgroup_classid(skb)
> + *     retrieve a proc's classid
> + *     @skb: pointer to skb
> + *     Return: classid if != 0
> + *
> + * int bpf_skb_vlan_push(skb, vlan_proto, vlan_tci)
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_vlan_pop(skb)
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_get_tunnel_key(skb, key, size, flags)
> + * int bpf_skb_set_tunnel_key(skb, key, size, flags)
> + *     retrieve or populate tunnel metadata
> + *     @skb: pointer to skb
> + *     @key: pointer to 'struct bpf_tunnel_key'
> + *     @size: size of 'struct bpf_tunnel_key'
> + *     @flags: room for future extensions
> + *     Return: 0 on success or negative error
> + *
> + * u64 bpf_perf_event_read(&map, index)
> + *     Return: Number events read or error code
> + *
> + * int bpf_redirect(ifindex, flags)
> + *     redirect to another netdev
> + *     @ifindex: ifindex of the net device
> + *     @flags: bit 0 - if set, redirect to ingress instead of egress
> + *             other bits - reserved
> + *     Return: TC_ACT_REDIRECT
> + *
> + * u32 bpf_get_route_realm(skb)
> + *     retrieve a dst's tclassid
> + *     @skb: pointer to skb
> + *     Return: realm if != 0
> + *
> + * int bpf_perf_event_output(ctx, map, index, data, size)
> + *     output perf raw sample
> + *     @ctx: struct pt_regs*
> + *     @map: pointer to perf_event_array map
> + *     @index: index of event in the map
> + *     @data: data on stack to be output as raw data
> + *     @size: size of data
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_get_stackid(ctx, map, flags)
> + *     walk user or kernel stack and return id
> + *     @ctx: struct pt_regs*
> + *     @map: pointer to stack_trace map
> + *     @flags: bits 0-7 - numer of stack frames to skip
> + *             bit 8 - collect user stack instead of kernel
> + *             bit 9 - compare stacks by hash only
> + *             bit 10 - if two different stacks hash into the same stackid
> + *                      discard old
> + *             other bits - reserved
> + *     Return: >= 0 stackid on success or negative error
> + *
> + * s64 bpf_csum_diff(from, from_size, to, to_size, seed)
> + *     calculate csum diff
> + *     @from: raw from buffer
> + *     @from_size: length of from buffer
> + *     @to: raw to buffer
> + *     @to_size: length of to buffer
> + *     @seed: optional seed
> + *     Return: csum result or negative error code
> + *
> + * int bpf_skb_get_tunnel_opt(skb, opt, size)
> + *     retrieve tunnel options metadata
> + *     @skb: pointer to skb
> + *     @opt: pointer to raw tunnel option data
> + *     @size: size of @opt
> + *     Return: option size
> + *
> + * int bpf_skb_set_tunnel_opt(skb, opt, size)
> + *     populate tunnel options metadata
> + *     @skb: pointer to skb
> + *     @opt: pointer to raw tunnel option data
> + *     @size: size of @opt
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_change_proto(skb, proto, flags)
> + *     Change protocol of the skb. Currently supported is v4 -> v6,
> + *     v6 -> v4 transitions. The helper will also resize the skb. eBPF
> + *     program is expected to fill the new headers via skb_store_bytes
> + *     and lX_csum_replace.
> + *     @skb: pointer to skb
> + *     @proto: new skb->protocol type
> + *     @flags: reserved
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_change_type(skb, type)
> + *     Change packet type of skb.
> + *     @skb: pointer to skb
> + *     @type: new skb->pkt_type type
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_under_cgroup(skb, map, index)
> + *     Check cgroup2 membership of skb
> + *     @skb: pointer to skb
> + *     @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
> + *     @index: index of the cgroup in the bpf_map
> + *     Return:
> + *       == 0 skb failed the cgroup2 descendant test
> + *       == 1 skb succeeded the cgroup2 descendant test
> + *        < 0 error
> + *
> + * u32 bpf_get_hash_recalc(skb)
> + *     Retrieve and possibly recalculate skb->hash.
> + *     @skb: pointer to skb
> + *     Return: hash
> + *
> + * u64 bpf_get_current_task(void)
> + *     Returns current task_struct
> + *     Return: current
> + *
> + * int bpf_probe_write_user(void *dst, void *src, int len)
> + *     safely attempt to write to a location
> + *     @dst: destination address in userspace
> + *     @src: source address on stack
> + *     @len: number of bytes to copy
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_current_task_under_cgroup(map, index)
> + *     Check cgroup2 membership of current task
> + *     @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
> + *     @index: index of the cgroup in the bpf_map
> + *     Return:
> + *       == 0 current failed the cgroup2 descendant test
> + *       == 1 current succeeded the cgroup2 descendant test
> + *        < 0 error
> + *
> + * int bpf_skb_change_tail(skb, len, flags)
> + *     The helper will resize the skb to the given new size, to be used f.e.
> + *     with control messages.
> + *     @skb: pointer to skb
> + *     @len: new skb length
> + *     @flags: reserved
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_skb_pull_data(skb, len)
> + *     The helper will pull in non-linear data in case the skb is non-linear
> + *     and not all of len are part of the linear section. Only needed for
> + *     read/write with direct packet access.
> + *     @skb: pointer to skb
> + *     @len: len to make read/writeable
> + *     Return: 0 on success or negative error
> + *
> + * s64 bpf_csum_update(skb, csum)
> + *     Adds csum into skb->csum in case of CHECKSUM_COMPLETE.
> + *     @skb: pointer to skb
> + *     @csum: csum to add
> + *     Return: csum on success or negative error
> + *
> + * void bpf_set_hash_invalid(skb)
> + *     Invalidate current skb->hash.
> + *     @skb: pointer to skb
> + *
> + * int bpf_get_numa_node_id()
> + *     Return: Id of current NUMA node.
> + *
> + * int bpf_skb_change_head()
> + *     Grows headroom of skb and adjusts MAC header offset accordingly.
> + *     Will extends/reallocae as required automatically.
> + *     May change skb data pointer and will thus invalidate any check
> + *     performed for direct packet access.
> + *     @skb: pointer to skb
> + *     @len: length of header to be pushed in front
> + *     @flags: Flags (unused for now)
> + *     Return: 0 on success or negative error
> + *
> + * int bpf_xdp_adjust_head(xdp_md, delta)
> + *     Adjust the xdp_md.data by delta
> + *     @xdp_md: pointer to xdp_md
> + *     @delta: An positive/negative integer to be added to xdp_md.data
> + *     Return: 0 on success or negative on error
> + *
> + * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
> + *     Copy a NUL terminated string from unsafe address. In case the string
> + *     length is smaller than size, the target is not padded with further NUL
> + *     bytes. In case the string length is larger than size, just count-1
> + *     bytes are copied and the last byte is set to NUL.
> + *     @dst: destination address
> + *     @size: maximum number of bytes to copy, including the trailing NUL
> + *     @unsafe_ptr: unsafe address
> + *     Return:
> + *       > 0 length of the string including the trailing NUL on success
> + *       < 0 error
> + *
> + * u64 bpf_get_socket_cookie(skb)
> + *     Get the cookie for the socket stored inside sk_buff.
> + *     @skb: pointer to skb
> + *     Return: 8 Bytes non-decreasing number on success or 0 if the socket
> + *     field is missing inside sk_buff
> + *
> + * u32 bpf_get_socket_uid(skb)
> + *     Get the owner uid of the socket stored inside sk_buff.
> + *     @skb: pointer to skb
> + *     Return: uid of the socket owner on success or overflowuid if failed.
> + */
> +#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),
> +
> +/* 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)
> +
> +/* BPF_FUNC_get_stackid flags. */
> +#define BPF_F_SKIP_FIELD_MASK		0xffULL
> +#define BPF_F_USER_STACK		(1ULL << 8)
> +#define BPF_F_FAST_STACK_CMP		(1ULL << 9)
> +#define BPF_F_REUSE_STACKID		(1ULL << 10)
> +
> +/* BPF_FUNC_skb_set_tunnel_key flags. */
> +#define BPF_F_ZERO_CSUM_TX		(1ULL << 1)
> +#define BPF_F_DONT_FRAGMENT		(1ULL << 2)
> +
> +/* BPF_FUNC_perf_event_output and BPF_FUNC_perf_event_read 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)
> +
> +/* 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;
> +};
> +
> +struct bpf_tunnel_key {
> +	__u32 tunnel_id;
> +	union {
> +		__u32 remote_ipv4;
> +		__u32 remote_ipv6[4];
> +	};
> +	__u8 tunnel_tos;
> +	__u8 tunnel_ttl;
> +	__u16 tunnel_ext;
> +	__u32 tunnel_label;
> +};
> +
> +/* 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 */
> +};
> +
> +struct bpf_sock {
> +	__u32 bound_dev_if;
> +	__u32 family;
> +	__u32 type;
> +	__u32 protocol;
> +};
> +
> +#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 drop.
> + */
> +enum xdp_action {
> +	XDP_ABORTED = 0,
> +	XDP_DROP,
> +	XDP_PASS,
> +	XDP_TX,
> +};
> +
> +/* 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;
> +};
> +
> +#endif /* __LINUX_BPF_H__ */
> diff --git a/scripts/update-linux-headers.sh b/scripts/update-linux-headers.sh
> index feb75390aa..616855bb6e 100755
> --- a/scripts/update-linux-headers.sh
> +++ b/scripts/update-linux-headers.sh
> @@ -126,7 +126,8 @@ done
>  rm -rf "$output/linux-headers/linux"
>  mkdir -p "$output/linux-headers/linux"
>  for header in kvm.h vfio.h vfio_ccw.h vhost.h \
> -              psci.h psp-sev.h userfaultfd.h; do
> +              psci.h psp-sev.h userfaultfd.h  \
> +              bpf.h; do
>      cp "$tmpdir/include/linux/$header" "$output/linux-headers/linux"
>  done
>  
> -- 
> 2.13.6
> 
> 

-- 
Murilo