[linux.git] / tools / net / bpf_exp.y

/*
 * BPF asm code parser
 *
 * This program is free software; you can distribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License,
 * or (at your option) any later version.
 *
 * Syntax kept close to:
 *
 * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
 * architecture for user-level packet capture. In Proceedings of the
 * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
 * Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
 * CA, USA, 2-2.
 *
 * Copyright 2013 Daniel Borkmann <[email protected]>
 * Licensed under the GNU General Public License, version 2.0 (GPLv2)
 */

%{

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <linux/filter.h>

#include "bpf_exp.yacc.h"

enum jmp_type { JTL, JFL, JKL };

extern FILE *yyin;
extern int yylineno;
extern int yylex(void);
extern void yyerror(const char *str);

extern void bpf_asm_compile(FILE *fp, bool cstyle);
static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k);
static void bpf_set_curr_label(char *label);
static void bpf_set_jmp_label(char *label, enum jmp_type type);

%}

%union {
	char *label;
	uint32_t number;
}

%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
%token OP_LDXI

%token K_PKT_LEN

%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'

%token extension number label

%type <label> label
%type <number> extension
%type <number> number

%%

prog
	: line
	| prog line
	;

line
	: instr
	| labelled_instr
	;

labelled_instr
	: labelled instr
	;

instr
	: ldb
	| ldh
	| ld
	| ldi
	| ldx
	| ldxi
	| st
	| stx
	| jmp
	| jeq
	| jneq
	| jlt
	| jle
	| jgt
	| jge
	| jset
	| add
	| sub
	| mul
	| div
	| mod
	| neg
	| and
	| or
	| xor
	| lsh
	| rsh
	| ret
	| tax
	| txa
	;

labelled
	: label ':' { bpf_set_curr_label($1); }
	;

ldb
	: OP_LDB '[' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
	| OP_LDB '[' '%' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $6); }
	| OP_LDB '[' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
	| OP_LDB extension {
		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
				   SKF_AD_OFF + $2); }
	;

ldh
	: OP_LDH '[' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
	| OP_LDH '[' '%' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $6); }
	| OP_LDH '[' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
	| OP_LDH extension {
		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
				   SKF_AD_OFF + $2); }
	;

ldi
	: OP_LDI '#' number {
		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
	| OP_LDI number {
		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); }
	;

ld
	: OP_LD '#' number {
		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
	| OP_LD K_PKT_LEN {
		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); }
	| OP_LD extension {
		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
				   SKF_AD_OFF + $2); }
	| OP_LD 'M' '[' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
	| OP_LD '[' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
	| OP_LD '[' '%' 'x' '+' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $6); }
	| OP_LD '[' number ']' {
		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
	;

ldxi
	: OP_LDXI '#' number {
		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
	| OP_LDXI number {
		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); }
	;

ldx
	: OP_LDX '#' number {
		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
	| OP_LDX K_PKT_LEN {
		bpf_set_curr_instr(BPF_LDX | BPF_W | BPF_LEN, 0, 0, 0); }
	| OP_LDX 'M' '[' number ']' {
		bpf_set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
	| OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
		if ($2 != 4 || $9 != 0xf) {
			fprintf(stderr, "ldxb offset not supported!\n");
			exit(0);
		} else {
			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
	| OP_LDX number '*' '(' '[' number ']' '&' number ')' {
		if ($2 != 4 || $9 != 0xf) {
			fprintf(stderr, "ldxb offset not supported!\n");
			exit(0);
		} else {
			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
	;

st
	: OP_ST 'M' '[' number ']' {
		bpf_set_curr_instr(BPF_ST, 0, 0, $4); }
	;

stx
	: OP_STX 'M' '[' number ']' {
		bpf_set_curr_instr(BPF_STX, 0, 0, $4); }
	;

jmp
	: OP_JMP label {
		bpf_set_jmp_label($2, JKL);
		bpf_set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
	;

jeq
	: OP_JEQ '#' number ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
	| OP_JEQ 'x' ',' label ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_jmp_label($6, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	| OP_JEQ '%' 'x' ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	| OP_JEQ '#' number ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
	| OP_JEQ 'x' ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	| OP_JEQ '%' 'x' ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	;

jneq
	: OP_JNEQ '#' number ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
	| OP_JNEQ 'x' ',' label {
		bpf_set_jmp_label($4, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	| OP_JNEQ '%' 'x' ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
	;

jlt
	: OP_JLT '#' number ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
	| OP_JLT 'x' ',' label {
		bpf_set_jmp_label($4, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	| OP_JLT '%' 'x' ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	;

jle
	: OP_JLE '#' number ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
	| OP_JLE 'x' ',' label {
		bpf_set_jmp_label($4, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	| OP_JLE '%' 'x' ',' label {
		bpf_set_jmp_label($5, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	;

jgt
	: OP_JGT '#' number ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
	| OP_JGT 'x' ',' label ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_jmp_label($6, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	| OP_JGT '%' 'x' ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	| OP_JGT '#' number ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
	| OP_JGT 'x' ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	| OP_JGT '%' 'x' ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
	;

jge
	: OP_JGE '#' number ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
	| OP_JGE 'x' ',' label ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_jmp_label($6, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	| OP_JGE '%' 'x' ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	| OP_JGE '#' number ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
	| OP_JGE 'x' ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	| OP_JGE '%' 'x' ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
	;

jset
	: OP_JSET '#' number ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
	| OP_JSET 'x' ',' label ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_jmp_label($6, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
	| OP_JSET '%' 'x' ',' label ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_jmp_label($7, JFL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
	| OP_JSET '#' number ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
	| OP_JSET 'x' ',' label {
		bpf_set_jmp_label($4, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
	| OP_JSET '%' 'x' ',' label {
		bpf_set_jmp_label($5, JTL);
		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
	;

add
	: OP_ADD '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
	| OP_ADD 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
	| OP_ADD '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
	;

sub
	: OP_SUB '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
	| OP_SUB 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
	| OP_SUB '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
	;

mul
	: OP_MUL '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
	| OP_MUL 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
	| OP_MUL '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
	;

div
	: OP_DIV '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
	| OP_DIV 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
	| OP_DIV '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
	;

mod
	: OP_MOD '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
	| OP_MOD 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
	| OP_MOD '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
	;

neg
	: OP_NEG {
		bpf_set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
	;

and
	: OP_AND '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
	| OP_AND 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
	| OP_AND '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
	;

or
	: OP_OR '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
	| OP_OR 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
	| OP_OR '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
	;

xor
	: OP_XOR '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
	| OP_XOR 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
	| OP_XOR '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
	;

lsh
	: OP_LSH '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
	| OP_LSH 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
	| OP_LSH '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
	;

rsh
	: OP_RSH '#' number {
		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
	| OP_RSH 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
	| OP_RSH '%' 'x' {
		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
	;

ret
	: OP_RET 'a' {
		bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
	| OP_RET '%' 'a' {
		bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
	| OP_RET 'x' {
		bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
	| OP_RET '%' 'x' {
		bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
	| OP_RET '#' number {
		bpf_set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
	;

tax
	: OP_TAX {
		bpf_set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
	;

txa
	: OP_TXA {
		bpf_set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
	;

%%

static int curr_instr = 0;
static struct sock_filter out[BPF_MAXINSNS];
static char **labels, **labels_jt, **labels_jf, **labels_k;

static void bpf_assert_max(void)
{
	if (curr_instr >= BPF_MAXINSNS) {
		fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS);
		exit(0);
	}
}

static void bpf_set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf,
			       uint32_t k)
{
	bpf_assert_max();
	out[curr_instr].code = code;
	out[curr_instr].jt = jt;
	out[curr_instr].jf = jf;
	out[curr_instr].k = k;
	curr_instr++;
}

static void bpf_set_curr_label(char *label)
{
	bpf_assert_max();
	labels[curr_instr] = label;
}

static void bpf_set_jmp_label(char *label, enum jmp_type type)
{
	bpf_assert_max();
	switch (type) {
	case JTL:
		labels_jt[curr_instr] = label;
		break;
	case JFL:
		labels_jf[curr_instr] = label;
		break;
	case JKL:
		labels_k[curr_instr] = label;
		break;
	}
}

static int bpf_find_insns_offset(const char *label)
{
	int i, max = curr_instr, ret = -ENOENT;

	for (i = 0; i < max; i++) {
		if (labels[i] && !strcmp(label, labels[i])) {
			ret = i;
			break;
		}
	}

	if (ret == -ENOENT) {
		fprintf(stderr, "no such label \'%s\'!\n", label);
		exit(0);
	}

	return ret;
}

static void bpf_stage_1_insert_insns(void)
{
	yyparse();
}

static void bpf_reduce_k_jumps(void)
{
	int i;

	for (i = 0; i < curr_instr; i++) {
		if (labels_k[i]) {
			int off = bpf_find_insns_offset(labels_k[i]);
			out[i].k = (uint32_t) (off - i - 1);
		}
	}
}

static void bpf_reduce_jt_jumps(void)
{
	int i;

	for (i = 0; i < curr_instr; i++) {
		if (labels_jt[i]) {
			int off = bpf_find_insns_offset(labels_jt[i]);
			out[i].jt = (uint8_t) (off - i -1);
		}
	}
}

static void bpf_reduce_jf_jumps(void)
{
	int i;

	for (i = 0; i < curr_instr; i++) {
		if (labels_jf[i]) {
			int off = bpf_find_insns_offset(labels_jf[i]);
			out[i].jf = (uint8_t) (off - i - 1);
		}
	}
}

static void bpf_stage_2_reduce_labels(void)
{
	bpf_reduce_k_jumps();
	bpf_reduce_jt_jumps();
	bpf_reduce_jf_jumps();
}

static void bpf_pretty_print_c(void)
{
	int i;

	for (i = 0; i < curr_instr; i++)
		printf("{ %#04x, %2u, %2u, %#010x },\n", out[i].code,
		       out[i].jt, out[i].jf, out[i].k);
}

static void bpf_pretty_print(void)
{
	int i;

	printf("%u,", curr_instr);
	for (i = 0; i < curr_instr; i++)
		printf("%u %u %u %u,", out[i].code,
		       out[i].jt, out[i].jf, out[i].k);
	printf("\n");
}

static void bpf_init(void)
{
	memset(out, 0, sizeof(out));

	labels = calloc(BPF_MAXINSNS, sizeof(*labels));
	assert(labels);
	labels_jt = calloc(BPF_MAXINSNS, sizeof(*labels_jt));
	assert(labels_jt);
	labels_jf = calloc(BPF_MAXINSNS, sizeof(*labels_jf));
	assert(labels_jf);
	labels_k = calloc(BPF_MAXINSNS, sizeof(*labels_k));
	assert(labels_k);
}

static void bpf_destroy_labels(void)
{
	int i;

	for (i = 0; i < curr_instr; i++) {
		free(labels_jf[i]);
		free(labels_jt[i]);
		free(labels_k[i]);
		free(labels[i]);
	}
}

static void bpf_destroy(void)
{
	bpf_destroy_labels();
	free(labels_jt);
	free(labels_jf);
	free(labels_k);
	free(labels);
}

void bpf_asm_compile(FILE *fp, bool cstyle)
{
	yyin = fp;

	bpf_init();
	bpf_stage_1_insert_insns();
	bpf_stage_2_reduce_labels();
	bpf_destroy();

	if (cstyle)
		bpf_pretty_print_c();
	else
		bpf_pretty_print();

	if (fp != stdin)
		fclose(yyin);
}

void yyerror(const char *str)
{
	fprintf(stderr, "error: %s at line %d\n", str, yylineno);
	exit(1);
}
Commit	Line	Data
3f356385 DB	1	/*
	2	* BPF asm code parser
	3	*
	4	* This program is free software; you can distribute it and/or modify
	5	* it under the terms of the GNU General Public License as published
	6	* by the Free Software Foundation; either version 2 of the License,
	7	* or (at your option) any later version.
	8	*
	9	* Syntax kept close to:
	10	*
	11	* Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
	12	* architecture for user-level packet capture. In Proceedings of the
	13	* USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
	14	* Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
	15	* CA, USA, 2-2.
	16	*
	17	* Copyright 2013 Daniel Borkmann <[email protected]>
	18	* Licensed under the GNU General Public License, version 2.0 (GPLv2)
	19	*/
	20
	21	%{
	22
	23	#include <stdio.h>
	24	#include <string.h>
	25	#include <stdint.h>
	26	#include <stdlib.h>
	27	#include <stdbool.h>
	28	#include <unistd.h>
	29	#include <errno.h>
	30	#include <assert.h>
	31	#include <linux/filter.h>
	32
	33	#include "bpf_exp.yacc.h"
	34
	35	enum jmp_type { JTL, JFL, JKL };
	36
	37	extern FILE *yyin;
b1d95ae5	38	extern int yylineno;
3f356385 DB	39	extern int yylex(void);
	40	extern void yyerror(const char *str);
	41
	42	extern void bpf_asm_compile(FILE *fp, bool cstyle);
	43	static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k);
d207cf4c DB	44	static void bpf_set_curr_label(char *label);
d207cf4c DB	45	static void bpf_set_jmp_label(char *label, enum jmp_type type);
3f356385 DB	46
	47	%}
	48
	49	%union {
	50	char *label;
	51	uint32_t number;
	52	}
	53
	54	%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
	55	%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
	56	%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
	57	%token OP_LDXI
	58
b1d95ae5	59	%token K_PKT_LEN
3f356385 DB	60
	61	%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'
	62
b1d95ae5	63	%token extension number label
3f356385 DB	64
3f356385 DB	65	%type <label> label
b1d95ae5	66	%type <number> extension
3f356385 DB	67	%type <number> number
	68
	69	%%
	70
	71	prog
	72	: line
	73	\| prog line
	74	;
	75
	76	line
	77	: instr
	78	\| labelled_instr
	79	;
	80
	81	labelled_instr
	82	: labelled instr
	83	;
	84
	85	instr
	86	: ldb
	87	\| ldh
	88	\| ld
	89	\| ldi
	90	\| ldx
	91	\| ldxi
	92	\| st
	93	\| stx
	94	\| jmp
	95	\| jeq
	96	\| jneq
	97	\| jlt
	98	\| jle
	99	\| jgt
	100	\| jge
	101	\| jset
	102	\| add
	103	\| sub
	104	\| mul
	105	\| div
	106	\| mod
	107	\| neg
	108	\| and
	109	\| or
	110	\| xor
	111	\| lsh
	112	\| rsh
	113	\| ret
	114	\| tax
	115	\| txa
	116	;
	117
	118	labelled
	119	: label ':' { bpf_set_curr_label($1); }
	120	;
	121
	122	ldb
	123	: OP_LDB '[' 'x' '+' number ']' {
	124	bpf_set_curr_instr(BPF_LD \| BPF_B \| BPF_IND, 0, 0, $5); }
	125	\| OP_LDB '[' '%' 'x' '+' number ']' {
	126	bpf_set_curr_instr(BPF_LD \| BPF_B \| BPF_IND, 0, 0, $6); }
	127	\| OP_LDB '[' number ']' {
	128	bpf_set_curr_instr(BPF_LD \| BPF_B \| BPF_ABS, 0, 0, $3); }
b1d95ae5	129	\| OP_LDB extension {
3f356385	130	bpf_set_curr_instr(BPF_LD \| BPF_B \| BPF_ABS, 0, 0,
b1d95ae5	131	SKF_AD_OFF + $2); }
3f356385 DB	132	;
	133
	134	ldh
	135	: OP_LDH '[' 'x' '+' number ']' {
	136	bpf_set_curr_instr(BPF_LD \| BPF_H \| BPF_IND, 0, 0, $5); }
	137	\| OP_LDH '[' '%' 'x' '+' number ']' {
	138	bpf_set_curr_instr(BPF_LD \| BPF_H \| BPF_IND, 0, 0, $6); }
	139	\| OP_LDH '[' number ']' {
	140	bpf_set_curr_instr(BPF_LD \| BPF_H \| BPF_ABS, 0, 0, $3); }
b1d95ae5	141	\| OP_LDH extension {
3f356385	142	bpf_set_curr_instr(BPF_LD \| BPF_H \| BPF_ABS, 0, 0,
b1d95ae5	143	SKF_AD_OFF + $2); }
3f356385 DB	144	;
	145
	146	ldi
	147	: OP_LDI '#' number {
	148	bpf_set_curr_instr(BPF_LD \| BPF_IMM, 0, 0, $3); }
	149	\| OP_LDI number {
	150	bpf_set_curr_instr(BPF_LD \| BPF_IMM, 0, 0, $2); }
	151	;
	152
	153	ld
	154	: OP_LD '#' number {
	155	bpf_set_curr_instr(BPF_LD \| BPF_IMM, 0, 0, $3); }
	156	\| OP_LD K_PKT_LEN {
	157	bpf_set_curr_instr(BPF_LD \| BPF_W \| BPF_LEN, 0, 0, 0); }
b1d95ae5	158	\| OP_LD extension {
27cd5452	159	bpf_set_curr_instr(BPF_LD \| BPF_W \| BPF_ABS, 0, 0,
b1d95ae5	160	SKF_AD_OFF + $2); }
3f356385 DB	161	\| OP_LD 'M' '[' number ']' {
	162	bpf_set_curr_instr(BPF_LD \| BPF_MEM, 0, 0, $4); }
	163	\| OP_LD '[' 'x' '+' number ']' {
	164	bpf_set_curr_instr(BPF_LD \| BPF_W \| BPF_IND, 0, 0, $5); }
	165	\| OP_LD '[' '%' 'x' '+' number ']' {
	166	bpf_set_curr_instr(BPF_LD \| BPF_W \| BPF_IND, 0, 0, $6); }
	167	\| OP_LD '[' number ']' {
	168	bpf_set_curr_instr(BPF_LD \| BPF_W \| BPF_ABS, 0, 0, $3); }
	169	;
	170
	171	ldxi
	172	: OP_LDXI '#' number {
	173	bpf_set_curr_instr(BPF_LDX \| BPF_IMM, 0, 0, $3); }
	174	\| OP_LDXI number {
	175	bpf_set_curr_instr(BPF_LDX \| BPF_IMM, 0, 0, $2); }
	176	;
	177
	178	ldx
	179	: OP_LDX '#' number {
	180	bpf_set_curr_instr(BPF_LDX \| BPF_IMM, 0, 0, $3); }
	181	\| OP_LDX K_PKT_LEN {
	182	bpf_set_curr_instr(BPF_LDX \| BPF_W \| BPF_LEN, 0, 0, 0); }
	183	\| OP_LDX 'M' '[' number ']' {
	184	bpf_set_curr_instr(BPF_LDX \| BPF_MEM, 0, 0, $4); }
	185	\| OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
	186	if ($2 != 4 \|\| $9 != 0xf) {
	187	fprintf(stderr, "ldxb offset not supported!\n");
	188	exit(0);
	189	} else {
	190	bpf_set_curr_instr(BPF_LDX \| BPF_MSH \| BPF_B, 0, 0, $6); } }
	191	\| OP_LDX number '*' '(' '[' number ']' '&' number ')' {
	192	if ($2 != 4 \|\| $9 != 0xf) {
	193	fprintf(stderr, "ldxb offset not supported!\n");
	194	exit(0);
	195	} else {
	196	bpf_set_curr_instr(BPF_LDX \| BPF_MSH \| BPF_B, 0, 0, $6); } }
	197	;
	198
	199	st
	200	: OP_ST 'M' '[' number ']' {
	201	bpf_set_curr_instr(BPF_ST, 0, 0, $4); }
	202	;
	203
	204	stx
	205	: OP_STX 'M' '[' number ']' {
	206	bpf_set_curr_instr(BPF_STX, 0, 0, $4); }
	207	;
	208
	209	jmp
	210	: OP_JMP label {
	211	bpf_set_jmp_label($2, JKL);
	212	bpf_set_curr_instr(BPF_JMP \| BPF_JA, 0, 0, 0); }
	213	;
	214
	215	jeq
	216	: OP_JEQ '#' number ',' label ',' label {
	217	bpf_set_jmp_label($5, JTL);
	218	bpf_set_jmp_label($7, JFL);
	219	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_K, 0, 0, $3); }
	220	\| OP_JEQ 'x' ',' label ',' label {
	221	bpf_set_jmp_label($4, JTL);
	222	bpf_set_jmp_label($6, JFL);
	223	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
	224	\| OP_JEQ '%' 'x' ',' label ',' label {
225	bpf_set_jmp_label($5, JTL);
226	bpf_set_jmp_label($7, JFL);
227	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
228	\| OP_JEQ '#' number ',' label {
229	bpf_set_jmp_label($5, JTL);
230	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_K, 0, 0, $3); }
231	\| OP_JEQ 'x' ',' label {
232	bpf_set_jmp_label($4, JTL);
233	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
234	\| OP_JEQ '%' 'x' ',' label {
235	bpf_set_jmp_label($5, JTL);
236	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
237	;
238
239	jneq
240	: OP_JNEQ '#' number ',' label {
241	bpf_set_jmp_label($5, JFL);
242	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_K, 0, 0, $3); }
243	\| OP_JNEQ 'x' ',' label {
244	bpf_set_jmp_label($4, JFL);
245	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
246	\| OP_JNEQ '%' 'x' ',' label {
247	bpf_set_jmp_label($5, JFL);
248	bpf_set_curr_instr(BPF_JMP \| BPF_JEQ \| BPF_X, 0, 0, 0); }
249	;
250
251	jlt
252	: OP_JLT '#' number ',' label {
253	bpf_set_jmp_label($5, JFL);
254	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_K, 0, 0, $3); }
255	\| OP_JLT 'x' ',' label {
256	bpf_set_jmp_label($4, JFL);
257	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
258	\| OP_JLT '%' 'x' ',' label {
259	bpf_set_jmp_label($5, JFL);
260	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
261	;
262
263	jle
264	: OP_JLE '#' number ',' label {
265	bpf_set_jmp_label($5, JFL);
266	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_K, 0, 0, $3); }
267	\| OP_JLE 'x' ',' label {
268	bpf_set_jmp_label($4, JFL);
269	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
270	\| OP_JLE '%' 'x' ',' label {
271	bpf_set_jmp_label($5, JFL);
272	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
273	;
274
275	jgt
276	: OP_JGT '#' number ',' label ',' label {
277	bpf_set_jmp_label($5, JTL);
278	bpf_set_jmp_label($7, JFL);
279	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_K, 0, 0, $3); }
280	\| OP_JGT 'x' ',' label ',' label {
281	bpf_set_jmp_label($4, JTL);
282	bpf_set_jmp_label($6, JFL);
283	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
284	\| OP_JGT '%' 'x' ',' label ',' label {
285	bpf_set_jmp_label($5, JTL);
286	bpf_set_jmp_label($7, JFL);
287	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
288	\| OP_JGT '#' number ',' label {
289	bpf_set_jmp_label($5, JTL);
290	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_K, 0, 0, $3); }
291	\| OP_JGT 'x' ',' label {
292	bpf_set_jmp_label($4, JTL);
293	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
294	\| OP_JGT '%' 'x' ',' label {
295	bpf_set_jmp_label($5, JTL);
296	bpf_set_curr_instr(BPF_JMP \| BPF_JGT \| BPF_X, 0, 0, 0); }
297	;
298
299	jge
300	: OP_JGE '#' number ',' label ',' label {
301	bpf_set_jmp_label($5, JTL);
302	bpf_set_jmp_label($7, JFL);
303	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_K, 0, 0, $3); }
304	\| OP_JGE 'x' ',' label ',' label {
305	bpf_set_jmp_label($4, JTL);
306	bpf_set_jmp_label($6, JFL);
307	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
308	\| OP_JGE '%' 'x' ',' label ',' label {
309	bpf_set_jmp_label($5, JTL);
310	bpf_set_jmp_label($7, JFL);
311	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
312	\| OP_JGE '#' number ',' label {
313	bpf_set_jmp_label($5, JTL);
314	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_K, 0, 0, $3); }
315	\| OP_JGE 'x' ',' label {
316	bpf_set_jmp_label($4, JTL);
317	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
318	\| OP_JGE '%' 'x' ',' label {
319	bpf_set_jmp_label($5, JTL);
320	bpf_set_curr_instr(BPF_JMP \| BPF_JGE \| BPF_X, 0, 0, 0); }
321	;
322
323	jset
324	: OP_JSET '#' number ',' label ',' label {
325	bpf_set_jmp_label($5, JTL);
326	bpf_set_jmp_label($7, JFL);
327	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_K, 0, 0, $3); }
328	\| OP_JSET 'x' ',' label ',' label {
329	bpf_set_jmp_label($4, JTL);
330	bpf_set_jmp_label($6, JFL);
331	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_X, 0, 0, 0); }
332	\| OP_JSET '%' 'x' ',' label ',' label {
333	bpf_set_jmp_label($5, JTL);
334	bpf_set_jmp_label($7, JFL);
335	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_X, 0, 0, 0); }
336	\| OP_JSET '#' number ',' label {
337	bpf_set_jmp_label($5, JTL);
338	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_K, 0, 0, $3); }
339	\| OP_JSET 'x' ',' label {
340	bpf_set_jmp_label($4, JTL);
341	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_X, 0, 0, 0); }
342	\| OP_JSET '%' 'x' ',' label {
343	bpf_set_jmp_label($5, JTL);
344	bpf_set_curr_instr(BPF_JMP \| BPF_JSET \| BPF_X, 0, 0, 0); }
345	;
346
347	add
348	: OP_ADD '#' number {
349	bpf_set_curr_instr(BPF_ALU \| BPF_ADD \| BPF_K, 0, 0, $3); }
350	\| OP_ADD 'x' {
351	bpf_set_curr_instr(BPF_ALU \| BPF_ADD \| BPF_X, 0, 0, 0); }
352	\| OP_ADD '%' 'x' {
353	bpf_set_curr_instr(BPF_ALU \| BPF_ADD \| BPF_X, 0, 0, 0); }
354	;
355
356	sub
357	: OP_SUB '#' number {
358	bpf_set_curr_instr(BPF_ALU \| BPF_SUB \| BPF_K, 0, 0, $3); }
359	\| OP_SUB 'x' {
360	bpf_set_curr_instr(BPF_ALU \| BPF_SUB \| BPF_X, 0, 0, 0); }
361	\| OP_SUB '%' 'x' {
362	bpf_set_curr_instr(BPF_ALU \| BPF_SUB \| BPF_X, 0, 0, 0); }
363	;
364
365	mul
366	: OP_MUL '#' number {
367	bpf_set_curr_instr(BPF_ALU \| BPF_MUL \| BPF_K, 0, 0, $3); }
368	\| OP_MUL 'x' {
369	bpf_set_curr_instr(BPF_ALU \| BPF_MUL \| BPF_X, 0, 0, 0); }
370	\| OP_MUL '%' 'x' {
371	bpf_set_curr_instr(BPF_ALU \| BPF_MUL \| BPF_X, 0, 0, 0); }
372	;
373
374	div
375	: OP_DIV '#' number {
376	bpf_set_curr_instr(BPF_ALU \| BPF_DIV \| BPF_K, 0, 0, $3); }
377	\| OP_DIV 'x' {
378	bpf_set_curr_instr(BPF_ALU \| BPF_DIV \| BPF_X, 0, 0, 0); }
379	\| OP_DIV '%' 'x' {
380	bpf_set_curr_instr(BPF_ALU \| BPF_DIV \| BPF_X, 0, 0, 0); }
381	;
382
383	mod
384	: OP_MOD '#' number {
385	bpf_set_curr_instr(BPF_ALU \| BPF_MOD \| BPF_K, 0, 0, $3); }
386	\| OP_MOD 'x' {
387	bpf_set_curr_instr(BPF_ALU \| BPF_MOD \| BPF_X, 0, 0, 0); }
388	\| OP_MOD '%' 'x' {
389	bpf_set_curr_instr(BPF_ALU \| BPF_MOD \| BPF_X, 0, 0, 0); }
390	;
391
392	neg
393	: OP_NEG {
394	bpf_set_curr_instr(BPF_ALU \| BPF_NEG, 0, 0, 0); }
395	;
396
397	and
398	: OP_AND '#' number {
399	bpf_set_curr_instr(BPF_ALU \| BPF_AND \| BPF_K, 0, 0, $3); }
400	\| OP_AND 'x' {
401	bpf_set_curr_instr(BPF_ALU \| BPF_AND \| BPF_X, 0, 0, 0); }
402	\| OP_AND '%' 'x' {
403	bpf_set_curr_instr(BPF_ALU \| BPF_AND \| BPF_X, 0, 0, 0); }
404	;
405
406	or
407	: OP_OR '#' number {
408	bpf_set_curr_instr(BPF_ALU \| BPF_OR \| BPF_K, 0, 0, $3); }
409	\| OP_OR 'x' {
410	bpf_set_curr_instr(BPF_ALU \| BPF_OR \| BPF_X, 0, 0, 0); }
411	\| OP_OR '%' 'x' {
412	bpf_set_curr_instr(BPF_ALU \| BPF_OR \| BPF_X, 0, 0, 0); }
413	;
414
415	xor
416	: OP_XOR '#' number {
417	bpf_set_curr_instr(BPF_ALU \| BPF_XOR \| BPF_K, 0, 0, $3); }
418	\| OP_XOR 'x' {
419	bpf_set_curr_instr(BPF_ALU \| BPF_XOR \| BPF_X, 0, 0, 0); }
420	\| OP_XOR '%' 'x' {
421	bpf_set_curr_instr(BPF_ALU \| BPF_XOR \| BPF_X, 0, 0, 0); }
422	;
423
424	lsh
425	: OP_LSH '#' number {
426	bpf_set_curr_instr(BPF_ALU \| BPF_LSH \| BPF_K, 0, 0, $3); }
427	\| OP_LSH 'x' {
428	bpf_set_curr_instr(BPF_ALU \| BPF_LSH \| BPF_X, 0, 0, 0); }
429	\| OP_LSH '%' 'x' {
430	bpf_set_curr_instr(BPF_ALU \| BPF_LSH \| BPF_X, 0, 0, 0); }
431	;
432
433	rsh
434	: OP_RSH '#' number {
435	bpf_set_curr_instr(BPF_ALU \| BPF_RSH \| BPF_K, 0, 0, $3); }
436	\| OP_RSH 'x' {
437	bpf_set_curr_instr(BPF_ALU \| BPF_RSH \| BPF_X, 0, 0, 0); }
438	\| OP_RSH '%' 'x' {
439	bpf_set_curr_instr(BPF_ALU \| BPF_RSH \| BPF_X, 0, 0, 0); }
440	;
441
442	ret
443	: OP_RET 'a' {
444	bpf_set_curr_instr(BPF_RET \| BPF_A, 0, 0, 0); }
445	\| OP_RET '%' 'a' {
446	bpf_set_curr_instr(BPF_RET \| BPF_A, 0, 0, 0); }
447	\| OP_RET 'x' {
448	bpf_set_curr_instr(BPF_RET \| BPF_X, 0, 0, 0); }
449	\| OP_RET '%' 'x' {
450	bpf_set_curr_instr(BPF_RET \| BPF_X, 0, 0, 0); }
451	\| OP_RET '#' number {
452	bpf_set_curr_instr(BPF_RET \| BPF_K, 0, 0, $3); }
453	;
454
455	tax
456	: OP_TAX {
457	bpf_set_curr_instr(BPF_MISC \| BPF_TAX, 0, 0, 0); }
458	;
459
460	txa
461	: OP_TXA {
462	bpf_set_curr_instr(BPF_MISC \| BPF_TXA, 0, 0, 0); }
463	;
464
465	%%
466
467	static int curr_instr = 0;
468	static struct sock_filter out[BPF_MAXINSNS];
d207cf4c	469	static char labels, labels_jt, labels_jf, labels_k;
3f356385 DB	470
	471	static void bpf_assert_max(void)
	472	{
	473	if (curr_instr >= BPF_MAXINSNS) {
	474	fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS);
	475	exit(0);
	476	}
	477	}
	478
	479	static void bpf_set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf,
	480	uint32_t k)
	481	{
	482	bpf_assert_max();
	483	out[curr_instr].code = code;
	484	out[curr_instr].jt = jt;
	485	out[curr_instr].jf = jf;
	486	out[curr_instr].k = k;
	487	curr_instr++;
	488	}
	489
d207cf4c	490	static void bpf_set_curr_label(char *label)
3f356385 DB	491	{
3f356385 DB	492	bpf_assert_max();
d207cf4c	493	labels[curr_instr] = label;
3f356385 DB	494	}
3f356385 DB	495
d207cf4c	496	static void bpf_set_jmp_label(char *label, enum jmp_type type)
3f356385 DB	497	{
	498	bpf_assert_max();
	499	switch (type) {
	500	case JTL:
	501	labels_jt[curr_instr] = label;
	502	break;
	503	case JFL:
	504	labels_jf[curr_instr] = label;
	505	break;
	506	case JKL:
	507	labels_k[curr_instr] = label;
	508	break;
	509	}
	510	}
	511
	512	static int bpf_find_insns_offset(const char *label)
	513	{
	514	int i, max = curr_instr, ret = -ENOENT;
	515
	516	for (i = 0; i < max; i++) {
	517	if (labels[i] && !strcmp(label, labels[i])) {
	518	ret = i;
	519	break;
	520	}
	521	}
	522
	523	if (ret == -ENOENT) {
	524	fprintf(stderr, "no such label \'%s\'!\n", label);
	525	exit(0);
	526	}
	527
	528	return ret;
	529	}
	530
	531	static void bpf_stage_1_insert_insns(void)
	532	{
	533	yyparse();
	534	}
	535
	536	static void bpf_reduce_k_jumps(void)
	537	{
	538	int i;
	539
	540	for (i = 0; i < curr_instr; i++) {
	541	if (labels_k[i]) {
	542	int off = bpf_find_insns_offset(labels_k[i]);
	543	out[i].k = (uint32_t) (off - i - 1);
	544	}
	545	}
	546	}
	547
	548	static void bpf_reduce_jt_jumps(void)
	549	{
	550	int i;
	551
	552	for (i = 0; i < curr_instr; i++) {
	553	if (labels_jt[i]) {
	554	int off = bpf_find_insns_offset(labels_jt[i]);
	555	out[i].jt = (uint8_t) (off - i -1);
	556	}
	557	}
	558	}
	559
	560	static void bpf_reduce_jf_jumps(void)
561	{
562	int i;
563
564	for (i = 0; i < curr_instr; i++) {
565	if (labels_jf[i]) {
566	int off = bpf_find_insns_offset(labels_jf[i]);
567	out[i].jf = (uint8_t) (off - i - 1);
568	}
569	}
570	}
571
572	static void bpf_stage_2_reduce_labels(void)
573	{
574	bpf_reduce_k_jumps();
575	bpf_reduce_jt_jumps();
576	bpf_reduce_jf_jumps();
577	}
578
579	static void bpf_pretty_print_c(void)
580	{
581	int i;
582
583	for (i = 0; i < curr_instr; i++)
584	printf("{ %#04x, %2u, %2u, %#010x },\n", out[i].code,
585	out[i].jt, out[i].jf, out[i].k);
586	}
587
588	static void bpf_pretty_print(void)
589	{
590	int i;
591
592	printf("%u,", curr_instr);
593	for (i = 0; i < curr_instr; i++)
594	printf("%u %u %u %u,", out[i].code,
595	out[i].jt, out[i].jf, out[i].k);
596	printf("\n");
597	}
598
599	static void bpf_init(void)
600	{
601	memset(out, 0, sizeof(out));
602
603	labels = calloc(BPF_MAXINSNS, sizeof(*labels));
604	assert(labels);
605	labels_jt = calloc(BPF_MAXINSNS, sizeof(*labels_jt));
606	assert(labels_jt);
607	labels_jf = calloc(BPF_MAXINSNS, sizeof(*labels_jf));
608	assert(labels_jf);
609	labels_k = calloc(BPF_MAXINSNS, sizeof(*labels_k));
610	assert(labels_k);
611	}
612
d207cf4c DB	613	static void bpf_destroy_labels(void)
	614	{
	615	int i;
	616
	617	for (i = 0; i < curr_instr; i++) {
	618	free(labels_jf[i]);
	619	free(labels_jt[i]);
	620	free(labels_k[i]);
	621	free(labels[i]);
	622	}
	623	}
	624
3f356385 DB	625	static void bpf_destroy(void)
3f356385 DB	626	{
d207cf4c	627	bpf_destroy_labels();
3f356385 DB	628	free(labels_jt);
	629	free(labels_jf);
	630	free(labels_k);
d207cf4c	631	free(labels);
3f356385 DB	632	}
	633
	634	void bpf_asm_compile(FILE *fp, bool cstyle)
	635	{
	636	yyin = fp;
	637
	638	bpf_init();
	639	bpf_stage_1_insert_insns();
	640	bpf_stage_2_reduce_labels();
	641	bpf_destroy();
	642
	643	if (cstyle)
	644	bpf_pretty_print_c();
	645	else
	646	bpf_pretty_print();
	647
	648	if (fp != stdin)
	649	fclose(yyin);
	650	}
	651
	652	void yyerror(const char *str)
	653	{
b1d95ae5	654	fprintf(stderr, "error: %s at line %d\n", str, yylineno);
3f356385 DB	655	exit(1);
3f356385 DB	656	}