From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sat, 27 Apr 2024 12:05:51 +0200
Subject: Adding upstream version 5.10.209.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 tools/bpf/bpf_exp.y | 666 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 666 insertions(+)
 create mode 100644 tools/bpf/bpf_exp.y

(limited to 'tools/bpf/bpf_exp.y')

diff --git a/tools/bpf/bpf_exp.y b/tools/bpf/bpf_exp.y
new file mode 100644
index 000000000..8d48e896b
--- /dev/null
+++ b/tools/bpf/bpf_exp.y
@@ -0,0 +1,666 @@
+/*
+ * 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 <borkmann@redhat.com>
+ * 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 uint8_t bpf_encode_jt_jf_offset(int off, int i)
+{
+	int delta = off - i - 1;
+
+	if (delta < 0 || delta > 255)
+		fprintf(stderr, "warning: insn #%d jumps to insn #%d, "
+				"which is out of range\n", i, off);
+	return (uint8_t) delta;
+}
+
+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 = bpf_encode_jt_jf_offset(off, i);
+		}
+	}
+}
+
+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 = bpf_encode_jt_jf_offset(off, i);
+		}
+	}
+}
+
+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);
+}
-- 
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