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/*-
* Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
* Copyright (C) 2005-2009 Jung-uk Kim <jkim@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Politecnico di Torino nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/i386/i386/bpf_jit_machdep.c 207081 2010-04-22 23:47:19Z jkim $");
#ifdef _KERNEL
#include "opt_bpf.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/malloc.h>
#include <net/if.h>
#else
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/param.h>
#endif
#include <sys/types.h>
#include <net/bpf.h>
#include <net/bpf_jitter.h>
#include <i386/i386/bpf_jit_machdep.h>
bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, size_t *);
/*
* Emit routine to update the jump table.
*/
static void
emit_length(bpf_bin_stream *stream, __unused u_int value, u_int len)
{
if (stream->refs != NULL)
(stream->refs)[stream->bpf_pc] += len;
stream->cur_ip += len;
}
/*
* Emit routine to output the actual binary code.
*/
static void
emit_code(bpf_bin_stream *stream, u_int value, u_int len)
{
switch (len) {
case 1:
stream->ibuf[stream->cur_ip] = (u_char)value;
stream->cur_ip++;
break;
case 2:
*((u_short *)(stream->ibuf + stream->cur_ip)) = (u_short)value;
stream->cur_ip += 2;
break;
case 4:
*((u_int *)(stream->ibuf + stream->cur_ip)) = value;
stream->cur_ip += 4;
break;
}
return;
}
/*
* Scan the filter program and find possible optimization.
*/
static int
bpf_jit_optimize(struct bpf_insn *prog, u_int nins)
{
int flags;
u_int i;
/* Do we return immediately? */
if (BPF_CLASS(prog[0].code) == BPF_RET)
return (BPF_JIT_FRET);
for (flags = 0, i = 0; i < nins; i++) {
switch (prog[i].code) {
case BPF_LD|BPF_W|BPF_ABS:
case BPF_LD|BPF_H|BPF_ABS:
case BPF_LD|BPF_B|BPF_ABS:
case BPF_LD|BPF_W|BPF_IND:
case BPF_LD|BPF_H|BPF_IND:
case BPF_LD|BPF_B|BPF_IND:
case BPF_LDX|BPF_MSH|BPF_B:
flags |= BPF_JIT_FPKT;
break;
case BPF_LD|BPF_MEM:
case BPF_LDX|BPF_MEM:
case BPF_ST:
case BPF_STX:
flags |= BPF_JIT_FMEM;
break;
case BPF_JMP|BPF_JA:
case BPF_JMP|BPF_JGT|BPF_K:
case BPF_JMP|BPF_JGE|BPF_K:
case BPF_JMP|BPF_JEQ|BPF_K:
case BPF_JMP|BPF_JSET|BPF_K:
case BPF_JMP|BPF_JGT|BPF_X:
case BPF_JMP|BPF_JGE|BPF_X:
case BPF_JMP|BPF_JEQ|BPF_X:
case BPF_JMP|BPF_JSET|BPF_X:
flags |= BPF_JIT_FJMP;
break;
case BPF_ALU|BPF_DIV|BPF_K:
flags |= BPF_JIT_FADK;
break;
}
if (flags == BPF_JIT_FLAG_ALL)
break;
}
return (flags);
}
/*
* Function that does the real stuff.
*/
bpf_filter_func
bpf_jit_compile(struct bpf_insn *prog, u_int nins, size_t *size)
{
bpf_bin_stream stream;
struct bpf_insn *ins;
int flags, fret, fpkt, fmem, fjmp, fadk;
int save_esp;
u_int i, pass;
/*
* NOTE: Do not modify the name of this variable, as it's used by
* the macros to emit code.
*/
emit_func emitm;
flags = bpf_jit_optimize(prog, nins);
fret = (flags & BPF_JIT_FRET) != 0;
fpkt = (flags & BPF_JIT_FPKT) != 0;
fmem = (flags & BPF_JIT_FMEM) != 0;
fjmp = (flags & BPF_JIT_FJMP) != 0;
fadk = (flags & BPF_JIT_FADK) != 0;
save_esp = (fpkt || fmem || fadk); /* Stack is used. */
if (fret)
nins = 1;
memset(&stream, 0, sizeof(stream));
/* Allocate the reference table for the jumps. */
if (fjmp) {
#ifdef _KERNEL
stream.refs = malloc((nins + 1) * sizeof(u_int), M_BPFJIT,
M_NOWAIT | M_ZERO);
#else
stream.refs = calloc(nins + 1, sizeof(u_int));
#endif
if (stream.refs == NULL)
return (NULL);
}
/*
* The first pass will emit the lengths of the instructions
* to create the reference table.
*/
emitm = emit_length;
for (pass = 0; pass < 2; pass++) {
ins = prog;
/* Create the procedure header. */
if (save_esp) {
PUSH(EBP);
MOVrd(ESP, EBP);
}
if (fmem)
SUBib(BPF_MEMWORDS * sizeof(uint32_t), ESP);
if (save_esp)
PUSH(ESI);
if (fpkt) {
PUSH(EDI);
PUSH(EBX);
MOVodd(8, EBP, EBX);
MOVodd(16, EBP, EDI);
}
for (i = 0; i < nins; i++) {
stream.bpf_pc++;
switch (ins->code) {
default:
#ifdef _KERNEL
return (NULL);
#else
abort();
#endif
case BPF_RET|BPF_K:
MOVid(ins->k, EAX);
if (save_esp) {
if (fpkt) {
POP(EBX);
POP(EDI);
}
POP(ESI);
LEAVE();
}
RET();
break;
case BPF_RET|BPF_A:
if (save_esp) {
if (fpkt) {
POP(EBX);
POP(EDI);
}
POP(ESI);
LEAVE();
}
RET();
break;
case BPF_LD|BPF_W|BPF_ABS:
MOVid(ins->k, ESI);
CMPrd(EDI, ESI);
JAb(12);
MOVrd(EDI, ECX);
SUBrd(ESI, ECX);
CMPid(sizeof(int32_t), ECX);
JAEb(7);
ZEROrd(EAX);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
MOVobd(EBX, ESI, EAX);
BSWAP(EAX);
break;
case BPF_LD|BPF_H|BPF_ABS:
ZEROrd(EAX);
MOVid(ins->k, ESI);
CMPrd(EDI, ESI);
JAb(12);
MOVrd(EDI, ECX);
SUBrd(ESI, ECX);
CMPid(sizeof(int16_t), ECX);
JAEb(5);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
MOVobw(EBX, ESI, AX);
SWAP_AX();
break;
case BPF_LD|BPF_B|BPF_ABS:
ZEROrd(EAX);
MOVid(ins->k, ESI);
CMPrd(EDI, ESI);
JBb(5);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
MOVobb(EBX, ESI, AL);
break;
case BPF_LD|BPF_W|BPF_LEN:
if (save_esp)
MOVodd(12, EBP, EAX);
else {
MOVrd(ESP, ECX);
MOVodd(12, ECX, EAX);
}
break;
case BPF_LDX|BPF_W|BPF_LEN:
if (save_esp)
MOVodd(12, EBP, EDX);
else {
MOVrd(ESP, ECX);
MOVodd(12, ECX, EDX);
}
break;
case BPF_LD|BPF_W|BPF_IND:
CMPrd(EDI, EDX);
JAb(27);
MOVid(ins->k, ESI);
MOVrd(EDI, ECX);
SUBrd(EDX, ECX);
CMPrd(ESI, ECX);
JBb(14);
ADDrd(EDX, ESI);
MOVrd(EDI, ECX);
SUBrd(ESI, ECX);
CMPid(sizeof(int32_t), ECX);
JAEb(7);
ZEROrd(EAX);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
MOVobd(EBX, ESI, EAX);
BSWAP(EAX);
break;
case BPF_LD|BPF_H|BPF_IND:
ZEROrd(EAX);
CMPrd(EDI, EDX);
JAb(27);
MOVid(ins->k, ESI);
MOVrd(EDI, ECX);
SUBrd(EDX, ECX);
CMPrd(ESI, ECX);
JBb(14);
ADDrd(EDX, ESI);
MOVrd(EDI, ECX);
SUBrd(ESI, ECX);
CMPid(sizeof(int16_t), ECX);
JAEb(5);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
MOVobw(EBX, ESI, AX);
SWAP_AX();
break;
case BPF_LD|BPF_B|BPF_IND:
ZEROrd(EAX);
CMPrd(EDI, EDX);
JAEb(13);
MOVid(ins->k, ESI);
MOVrd(EDI, ECX);
SUBrd(EDX, ECX);
CMPrd(ESI, ECX);
JAb(5);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
ADDrd(EDX, ESI);
MOVobb(EBX, ESI, AL);
break;
case BPF_LDX|BPF_MSH|BPF_B:
MOVid(ins->k, ESI);
CMPrd(EDI, ESI);
JBb(7);
ZEROrd(EAX);
POP(EBX);
POP(EDI);
POP(ESI);
LEAVE();
RET();
ZEROrd(EDX);
MOVobb(EBX, ESI, DL);
ANDib(0x0f, DL);
SHLib(2, EDX);
break;
case BPF_LD|BPF_IMM:
MOVid(ins->k, EAX);
break;
case BPF_LDX|BPF_IMM:
MOVid(ins->k, EDX);
break;
case BPF_LD|BPF_MEM:
MOVrd(EBP, ECX);
MOVid(((int)ins->k - BPF_MEMWORDS) *
sizeof(uint32_t), ESI);
MOVobd(ECX, ESI, EAX);
break;
case BPF_LDX|BPF_MEM:
MOVrd(EBP, ECX);
MOVid(((int)ins->k - BPF_MEMWORDS) *
sizeof(uint32_t), ESI);
MOVobd(ECX, ESI, EDX);
break;
case BPF_ST:
/*
* XXX this command and the following could
* be optimized if the previous instruction
* was already of this type
*/
MOVrd(EBP, ECX);
MOVid(((int)ins->k - BPF_MEMWORDS) *
sizeof(uint32_t), ESI);
MOVomd(EAX, ECX, ESI);
break;
case BPF_STX:
MOVrd(EBP, ECX);
MOVid(((int)ins->k - BPF_MEMWORDS) *
sizeof(uint32_t), ESI);
MOVomd(EDX, ECX, ESI);
break;
case BPF_JMP|BPF_JA:
JUMP(ins->k);
break;
case BPF_JMP|BPF_JGT|BPF_K:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPid(ins->k, EAX);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_K:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPid(ins->k, EAX);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_K:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPid(ins->k, EAX);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_K:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
TESTid(ins->k, EAX);
JCC(JNE, JE);
break;
case BPF_JMP|BPF_JGT|BPF_X:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPrd(EDX, EAX);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_X:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPrd(EDX, EAX);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_X:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
CMPrd(EDX, EAX);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_X:
if (ins->jt == ins->jf) {
JUMP(ins->jt);
break;
}
TESTrd(EDX, EAX);
JCC(JNE, JE);
break;
case BPF_ALU|BPF_ADD|BPF_X:
ADDrd(EDX, EAX);
break;
case BPF_ALU|BPF_SUB|BPF_X:
SUBrd(EDX, EAX);
break;
case BPF_ALU|BPF_MUL|BPF_X:
MOVrd(EDX, ECX);
MULrd(EDX);
MOVrd(ECX, EDX);
break;
case BPF_ALU|BPF_DIV|BPF_X:
TESTrd(EDX, EDX);
if (save_esp) {
if (fpkt) {
JNEb(7);
ZEROrd(EAX);
POP(EBX);
POP(EDI);
} else {
JNEb(5);
ZEROrd(EAX);
}
POP(ESI);
LEAVE();
} else {
JNEb(3);
ZEROrd(EAX);
}
RET();
MOVrd(EDX, ECX);
ZEROrd(EDX);
DIVrd(ECX);
MOVrd(ECX, EDX);
break;
case BPF_ALU|BPF_AND|BPF_X:
ANDrd(EDX, EAX);
break;
case BPF_ALU|BPF_OR|BPF_X:
ORrd(EDX, EAX);
break;
case BPF_ALU|BPF_LSH|BPF_X:
MOVrd(EDX, ECX);
SHL_CLrb(EAX);
break;
case BPF_ALU|BPF_RSH|BPF_X:
MOVrd(EDX, ECX);
SHR_CLrb(EAX);
break;
case BPF_ALU|BPF_ADD|BPF_K:
ADD_EAXi(ins->k);
break;
case BPF_ALU|BPF_SUB|BPF_K:
SUB_EAXi(ins->k);
break;
case BPF_ALU|BPF_MUL|BPF_K:
MOVrd(EDX, ECX);
MOVid(ins->k, EDX);
MULrd(EDX);
MOVrd(ECX, EDX);
break;
case BPF_ALU|BPF_DIV|BPF_K:
MOVrd(EDX, ECX);
ZEROrd(EDX);
MOVid(ins->k, ESI);
DIVrd(ESI);
MOVrd(ECX, EDX);
break;
case BPF_ALU|BPF_AND|BPF_K:
ANDid(ins->k, EAX);
break;
case BPF_ALU|BPF_OR|BPF_K:
ORid(ins->k, EAX);
break;
case BPF_ALU|BPF_LSH|BPF_K:
SHLib((ins->k) & 0xff, EAX);
break;
case BPF_ALU|BPF_RSH|BPF_K:
SHRib((ins->k) & 0xff, EAX);
break;
case BPF_ALU|BPF_NEG:
NEGd(EAX);
break;
case BPF_MISC|BPF_TAX:
MOVrd(EAX, EDX);
break;
case BPF_MISC|BPF_TXA:
MOVrd(EDX, EAX);
break;
}
ins++;
}
if (pass > 0)
continue;
*size = stream.cur_ip;
#ifdef _KERNEL
stream.ibuf = malloc(*size, M_BPFJIT, M_NOWAIT);
if (stream.ibuf == NULL)
break;
#else
stream.ibuf = mmap(NULL, *size, PROT_READ | PROT_WRITE,
MAP_ANON, -1, 0);
if (stream.ibuf == MAP_FAILED) {
stream.ibuf = NULL;
break;
}
#endif
/*
* Modify the reference table to contain the offsets and
* not the lengths of the instructions.
*/
if (fjmp)
for (i = 1; i < nins + 1; i++)
stream.refs[i] += stream.refs[i - 1];
/* Reset the counters. */
stream.cur_ip = 0;
stream.bpf_pc = 0;
/* The second pass creates the actual code. */
emitm = emit_code;
}
/*
* The reference table is needed only during compilation,
* now we can free it.
*/
if (fjmp)
#ifdef _KERNEL
free(stream.refs, M_BPFJIT);
#else
free(stream.refs);
#endif
#ifndef _KERNEL
if (stream.ibuf != NULL &&
mprotect(stream.ibuf, *size, PROT_READ | PROT_EXEC) != 0) {
munmap(stream.ibuf, *size);
stream.ibuf = NULL;
}
#endif
return ((bpf_filter_func)stream.ibuf);
}