/* 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 */
};

/* 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,
};

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,
};

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,
};

#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)

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 */
	};

	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 */
	};

	struct { /* anonymous struct used by BPF_OBJ_* commands */
		__aligned_u64	pathname;
		__u32		bpf_fd;
	};
} __attribute__((aligned(8)));

/* integer value in 'imm' field of BPF_CALL instruction selects which helper
 * function eBPF program intends to call
 */
enum bpf_func_id {
	BPF_FUNC_unspec,
	BPF_FUNC_map_lookup_elem, /* void *map_lookup_elem(&map, &key) */
	BPF_FUNC_map_update_elem, /* int map_update_elem(&map, &key, &value, flags) */
	BPF_FUNC_map_delete_elem, /* int map_delete_elem(&map, &key) */
	BPF_FUNC_probe_read,      /* int bpf_probe_read(void *dst, int size, void *src) */
	BPF_FUNC_ktime_get_ns,    /* u64 bpf_ktime_get_ns(void) */
	BPF_FUNC_trace_printk,    /* int bpf_trace_printk(const char *fmt, int fmt_size, ...) */
	BPF_FUNC_get_prandom_u32, /* u32 prandom_u32(void) */
	BPF_FUNC_get_smp_processor_id, /* u32 raw_smp_processor_id(void) */

	/**
	 * 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
	 */
	BPF_FUNC_skb_store_bytes,

	/**
	 * 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
	 */
	BPF_FUNC_l3_csum_replace,

	/**
	 * 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
	 */
	BPF_FUNC_l4_csum_replace,

	/**
	 * 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
	 */
	BPF_FUNC_tail_call,

	/**
	 * 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
	 */
	BPF_FUNC_clone_redirect,

	/**
	 * u64 bpf_get_current_pid_tgid(void)
	 * Return: current->tgid << 32 | current->pid
	 */
	BPF_FUNC_get_current_pid_tgid,

	/**
	 * u64 bpf_get_current_uid_gid(void)
	 * Return: current_gid << 32 | current_uid
	 */
	BPF_FUNC_get_current_uid_gid,

	/**
	 * bpf_get_current_comm(char *buf, int size_of_buf)
	 * stores current->comm into buf
	 * Return: 0 on success
	 */
	BPF_FUNC_get_current_comm,

	/**
	 * bpf_get_cgroup_classid(skb) - retrieve a proc's classid
	 * @skb: pointer to skb
	 * Return: classid if != 0
	 */
	BPF_FUNC_get_cgroup_classid,
	BPF_FUNC_skb_vlan_push, /* bpf_skb_vlan_push(skb, vlan_proto, vlan_tci) */
	BPF_FUNC_skb_vlan_pop,  /* bpf_skb_vlan_pop(skb) */

	/**
	 * bpf_skb_[gs]et_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
	 * Retrun: 0 on success
	 */
	BPF_FUNC_skb_get_tunnel_key,
	BPF_FUNC_skb_set_tunnel_key,
	BPF_FUNC_perf_event_read,	/* u64 bpf_perf_event_read(&map, index) */
	/**
	 * 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
	 */
	BPF_FUNC_redirect,

	/**
	 * bpf_get_route_realm(skb) - retrieve a dst's tclassid
	 * @skb: pointer to skb
	 * Return: realm if != 0
	 */
	BPF_FUNC_get_route_realm,

	/**
	 * 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
	 */
	BPF_FUNC_perf_event_output,
	BPF_FUNC_skb_load_bytes,

	/**
	 * 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
	 */
	BPF_FUNC_get_stackid,

	/**
	 * 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
	 */
	BPF_FUNC_csum_diff,

	/**
	 * bpf_skb_[gs]et_tunnel_opt(skb, opt, size)
	 * retrieve or populate tunnel options metadata
	 * @skb: pointer to skb
	 * @opt: pointer to raw tunnel option data
	 * @size: size of @opt
	 * Return: 0 on success for set, option size for get
	 */
	BPF_FUNC_skb_get_tunnel_opt,
	BPF_FUNC_skb_set_tunnel_opt,
	__BPF_FUNC_MAX_ID,
};

/* 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)

/* 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)

/* 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;
};

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;
};

#endif /* __LINUX_BPF_H__ */
