Add a small disassembler.
This commit is contained in:
christos
parent
049fba3c32
commit
a2855f0d2c
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@ -1,16 +1,18 @@
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# $NetBSD: Makefile,v 1.5 2012/01/08 21:34:21 rmind Exp $
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# $NetBSD: Makefile,v 1.6 2012/03/10 22:21:50 christos Exp $
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PROG= npfctl
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MAN= npfctl.8 npf.conf.5
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SRCS= npfctl.c npf_var.c npf_data.c npf_ncgen.c npf_build.c
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SRCS= npfctl.c npf_var.c npf_data.c npf_ncgen.c npf_build.c \
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npf_disassemble.c
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CPPFLAGS+= -I${.CURDIR}
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SRCS+= npf_scan.l npf_parse.y
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YHEADER= 1
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YFLAGS+= -v
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LDADD+= -lnpf -lprop -ly
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DPADD+= ${LIBNPF} ${LIBPROP}
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LDADD+= -lnpf -lprop -lutil -ly
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DPADD+= ${LIBNPF} ${LIBPROP} ${LIBUTIL}
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WARNS?= 4
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NOLINT= # disabled (note: deliberately)
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@ -0,0 +1,246 @@
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/* $NetBSD: npf_disassemble.c,v 1.1 2012/03/10 22:21:50 christos Exp $ */
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/*-
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* Copyright (c) 2012 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christos Zoulas.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: npf_disassemble.c,v 1.1 2012/03/10 22:21:50 christos Exp $");
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <err.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <util.h>
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#define NPF_OPCODES_STRINGS
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#include <net/npf_ncode.h>
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#include "npfctl.h"
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#define ADVANCE(n, rv) \
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do { \
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if (len < sizeof(*pc) * (n)) { \
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warnx("ran out of bytes"); \
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return rv; \
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} \
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pc += (n); \
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len -= sizeof(*pc) * (n); \
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} while (/*CONSTCOND*/0)
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static size_t
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npfctl_ncode_get_target(const uint32_t *pc, const uint32_t **t, size_t l)
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{
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for (size_t i = 0; i < l; i++)
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if (t[i] == pc)
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return i;
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return ~0;
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}
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static size_t
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npfctl_ncode_add_target(const uint32_t *pc, const uint32_t ***t, size_t *l,
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size_t *m)
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{
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size_t q = npfctl_ncode_get_target(pc, *t, *l);
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if (q != (size_t)~0)
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return q;
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if (*l <= *m) {
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*m += 10;
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*t = xrealloc(*t, *m * sizeof(**t));
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}
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q = *l;
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(*t)[(*l)++] = pc;
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return q;
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}
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static const char *
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npfctl_ncode_operand(char *buf, size_t bufsiz, uint8_t op, const uint32_t *st,
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const uint32_t **pcv, size_t *lenv, const uint32_t ***t, size_t *l,
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size_t *m)
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{
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const uint32_t *pc = *pcv;
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size_t len = *lenv;
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struct sockaddr_storage ss;
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switch (op) {
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case NPF_OPERAND_NONE:
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abort();
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case NPF_OPERAND_REGISTER:
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if (*pc & ~0x3) {
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warnx("Bad register operand 0x%x at offset %td",
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*pc, pc - st);
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return NULL;
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}
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snprintf(buf, bufsiz, "R%d", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_KEY:
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snprintf(buf, bufsiz, "key=<0x%x>", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_VALUE:
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snprintf(buf, bufsiz, "value=<0x%x>", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_SD:
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if (*pc & ~0x1) {
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warnx("Bad src/dst operand 0x%x at offset %td",
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*pc, pc - st);
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return NULL;
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}
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snprintf(buf, bufsiz, "%s", *pc == NPF_OPERAND_SD_SRC ?
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"SRC" : "DST");
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_REL_ADDRESS:
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snprintf(buf, bufsiz, "+%zu",
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npfctl_ncode_add_target(pc + *pc - 1, t, l, m));
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_NET_ADDRESS4: {
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struct sockaddr_in *sin = (void *)&ss;
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sin->sin_len = sizeof(*sin);
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sin->sin_family = AF_INET;
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sin->sin_port = 0;
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memcpy(&sin->sin_addr, pc, sizeof(sin->sin_addr));
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sockaddr_snprintf(buf, bufsiz, "%a", (struct sockaddr *)(void *)
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sin);
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ADVANCE(sizeof(sin->sin_addr) / sizeof(*pc), NULL);
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break;
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}
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case NPF_OPERAND_NET_ADDRESS6: {
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struct sockaddr_in6 *sin6 = (void *)&ss;
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sin6->sin6_len = sizeof(*sin6);
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sin6->sin6_family = AF_INET6;
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sin6->sin6_port = 0;
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memcpy(&sin6->sin6_addr, pc, sizeof(sin6->sin6_addr));
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sockaddr_snprintf(buf, bufsiz, "%a", (struct sockaddr *)(void *)
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sin6);
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ADVANCE(sizeof(sin6->sin6_addr) / sizeof(*pc), NULL);
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break;
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}
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case NPF_OPERAND_ETHER_TYPE:
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snprintf(buf, bufsiz, "ether=0x%x", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_SUBNET:
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snprintf(buf, bufsiz, "/%d", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_LENGTH:
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snprintf(buf, bufsiz, "length=%d", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_TABLE_ID:
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snprintf(buf, bufsiz, "id=%d", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_ICMP4_TYPE_CODE:
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snprintf(buf, bufsiz, "icmp=0x%x", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_TCP_FLAGS_MASK:
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snprintf(buf, bufsiz, "flmask=0x%x", *pc);
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ADVANCE(1, NULL);
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break;
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case NPF_OPERAND_PORT_RANGE:
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snprintf(buf, bufsiz, "%d-%d", (*pc >> 16), *pc & 0xffff);
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ADVANCE(1, NULL);
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break;
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default:
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warnx("invalid operand %d at offset %td", op, pc - st);
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return NULL;
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}
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*pcv = pc;
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*lenv = len;
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return buf;
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}
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int
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npfctl_ncode_disassemble(FILE *fp, const void *v, size_t len)
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{
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const uint32_t *pc = v;
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const uint32_t *st = v;
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const struct npf_instruction *ni;
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char buf[256];
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const uint32_t **targ;
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size_t tlen, mlen, target;
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targ = NULL;
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mlen = tlen = 0;
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while (len) {
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/* Get the opcode */
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if (*pc & ~0xff) {
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warnx("bad opcode 0x%x at offset (%td)", *pc,
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pc - st);
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return -1;
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}
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ni = &npf_instructions[*pc];
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if (ni->name == NULL) {
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warnx("invalid opcode 0x%x at offset (%td)", *pc,
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pc - st);
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return -1;
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}
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target = npfctl_ncode_get_target(pc, targ, tlen);
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if (target != (size_t)~0)
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printf("%zu:", target);
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fprintf(fp, "\t%s", ni->name);
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ADVANCE(1, -1);
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for (size_t i = 0; i < __arraycount(ni->op); i++) {
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const char *op;
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if (ni->op[i] == NPF_OPERAND_NONE)
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break;
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op = npfctl_ncode_operand(buf, sizeof(buf), ni->op[i],
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st, &pc, &len, &targ, &tlen, &mlen);
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if (op == NULL)
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return -1;
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fprintf(fp, "%s%s", i == 0 ? " " : ", ", op);
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}
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fprintf(fp, "\n");
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}
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return 0;
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}
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@ -1,4 +1,4 @@
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/* $NetBSD: npf_ncgen.c,v 1.7 2012/01/09 01:47:09 rmind Exp $ */
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/* $NetBSD: npf_ncgen.c,v 1.8 2012/03/10 22:21:50 christos Exp $ */
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/*-
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* Copyright (c) 2009-2012 The NetBSD Foundation, Inc.
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@ -34,7 +34,7 @@
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: npf_ncgen.c,v 1.7 2012/01/09 01:47:09 rmind Exp $");
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__RCSID("$NetBSD: npf_ncgen.c,v 1.8 2012/03/10 22:21:50 christos Exp $");
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#include <stdlib.h>
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#include <stddef.h>
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@ -388,10 +388,14 @@ npfctl_gennc_tcpfl(nc_ctx_t *ctx, uint8_t tf, uint8_t tf_mask)
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void
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npfctl_ncgen_print(const void *code, size_t len)
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{
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#if 0
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const uint32_t *op = code;
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while (len) {
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printf("\t> |0x%02x|\n", (u_int)*op++);
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len -= sizeof(*op);
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}
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#else
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npfctl_ncode_disassemble(stdout, code, len);
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#endif
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}
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@ -1,4 +1,4 @@
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/* $NetBSD: npfctl.h,v 1.12 2012/02/26 21:50:05 christos Exp $ */
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/* $NetBSD: npfctl.h,v 1.13 2012/03/10 22:21:50 christos Exp $ */
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/*-
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* Copyright (c) 2009-2012 The NetBSD Foundation, Inc.
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@ -154,5 +154,6 @@ void npfctl_build_rule(int, u_int, sa_family_t,
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void npfctl_build_nat(int, u_int, const filt_opts_t *,
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npfvar_t *, npfvar_t *);
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void npfctl_build_table(const char *, u_int, const char *);
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int npfctl_ncode_disassemble(FILE *, const void *, size_t);
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#endif
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