-/* From NetBSD: bpf_filter.c,v 1.12 1996/02/13 22:00:00 christos Exp */
-
-/*
- * Copyright (c) 1990, 1991, 1992, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from the Stanford/CMU enet packet filter,
- * (net/enet.c) distributed as part of 4.3BSD, and code contributed
- * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
- * Berkeley Laboratory.
- *
- * 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. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
- *
- * From: @(#)bpf_filter.c 8.1 (Berkeley) 6/10/93
- * $Id: bpf_filter.c,v 1.1 1996/04/04 02:45:45 paulus Exp $
- */
-
-#include <sys/param.h>
-#include <sys/types.h>
-#include <sys/stream.h>
-#include <net/ppp_defs.h>
-#include "ppp_mod.h"
-
-#ifdef SVR4
-#ifndef __GNUC__
-#include <sys/byteorder.h> /* for ntohl, etc. */
-#else
-/* make sure we don't get the gnu "fixed" one! */
-#include "/usr/include/sys/byteorder.h"
-#endif
-#endif
-
-#ifdef OSF1
-#include <net/net_globals.h>
-#endif
-#include <netinet/in.h>
-
-#ifdef AIX4
-#define _NETINET_IN_SYSTM_H_
-typedef u_long n_long;
-#else
-#include <netinet/in_systm.h>
-#endif
-
-#if !(defined(__i386__) || defined(__m68k__)) /* any others? */
-#define BPF_ALIGN
-#endif
-
-#ifndef BPF_ALIGN
-#define EXTRACT_SHORT(p) ((ushort)ntohs(*(ushort *)p))
-#define EXTRACT_LONG(p) (ntohl(*(uint *)p))
-#else
-#define EXTRACT_SHORT(p)\
- ((ushort)\
- ((ushort)*((u_char *)p+0)<<8|\
- (ushort)*((u_char *)p+1)<<0))
-#define EXTRACT_LONG(p)\
- ((uint)*((u_char *)p+0)<<24|\
- (uint)*((u_char *)p+1)<<16|\
- (uint)*((u_char *)p+2)<<8|\
- (uint)*((u_char *)p+3)<<0)
-#endif
-
-#ifdef _KERNEL
-#define MINDEX(len, m, k) \
-{ \
- len = m->b_wptr - m->b_rptr; \
- while (k >= len) { \
- k -= len; \
- m = m->b_cont; \
- if (m == 0) \
- return 0; \
- len = m->b_wptr - m->b_rptr; \
- } \
-}
-
-static int m_xword __P((mblk_t *, int, int *));
-static int m_xhalf __P((mblk_t *, int, int *));
-
-static int
-m_xword(m, k, err)
- register mblk_t *m;
- register int k, *err;
-{
- register int len;
- register uchar_t *cp, *np;
- register mblk_t *m0;
-
- MINDEX(len, m, k);
- cp = m->b_rptr + k;
- if (len - k >= 4) {
- *err = 0;
- return EXTRACT_LONG(cp);
- }
- m0 = m->b_cont;
- if (m0 == 0 || m0->b_wptr - m0->b_rptr + len - k < 4)
- goto bad;
- *err = 0;
- np = m0->b_rptr;
- switch (len - k) {
-
- case 1:
- return (cp[0] << 24) | (np[0] << 16) | (np[1] << 8) | np[2];
-
- case 2:
- return (cp[0] << 24) | (cp[1] << 16) | (np[0] << 8) | np[1];
-
- default:
- return (cp[0] << 24) | (cp[1] << 16) | (cp[2] << 8) | np[0];
- }
- bad:
- *err = 1;
- return 0;
-}
-
-static int
-m_xhalf(m, k, err)
- register mblk_t *m;
- register int k, *err;
-{
- register int len;
- register uchar_t *cp;
- register mblk_t *m0;
-
- MINDEX(len, m, k);
- cp = m->b_rptr + k;
- if (len - k >= 2) {
- *err = 0;
- return EXTRACT_SHORT(cp);
- }
- m0 = m->b_cont;
- if (m0 == 0)
- goto bad;
- *err = 0;
- return (cp[0] << 8) | m0->b_rptr[0];
- bad:
- *err = 1;
- return 0;
-}
-#endif
-
-#include <net/bpf.h>
-
-/*
- * Execute the filter program starting at pc on the packet p
- * wirelen is the length of the original packet
- * buflen is the amount of data present
- */
-uint
-bpf_filter(pc, p, wirelen, buflen)
- register struct bpf_insn *pc;
- register uchar_t *p;
- uint wirelen;
- register uint buflen;
-{
- register uint A = 0, X = 0;
- register int k;
- int mem[BPF_MEMWORDS];
-
- if (pc == 0)
- /*
- * No filter means accept all.
- */
- return (uint)-1;
- --pc;
- while (1) {
- ++pc;
- switch (pc->code) {
-
- default:
-#ifdef _KERNEL
- return 0;
-#else
- abort();
-#endif
- case BPF_RET|BPF_K:
- return (uint)pc->k;
-
- case BPF_RET|BPF_A:
- return (uint)A;
-
- case BPF_LD|BPF_W|BPF_ABS:
- k = pc->k;
- if (k + sizeof(int) > buflen) {
-#ifdef _KERNEL
- int merr;
-
- if (buflen != 0)
- return 0;
- A = m_xword((mblk_t *)p, k, &merr);
- if (merr != 0)
- return 0;
- continue;
-#else
- return 0;
-#endif
- }
- A = EXTRACT_LONG(&p[k]);
- continue;
-
- case BPF_LD|BPF_H|BPF_ABS:
- k = pc->k;
- if (k + sizeof(short int) > buflen) {
-#ifdef _KERNEL
- int merr;
-
- if (buflen != 0)
- return 0;
- A = m_xhalf((mblk_t *)p, k, &merr);
- continue;
-#else
- return 0;
-#endif
- }
- A = EXTRACT_SHORT(&p[k]);
- continue;
-
- case BPF_LD|BPF_B|BPF_ABS:
- k = pc->k;
- if (k >= buflen) {
-#ifdef _KERNEL
- register mblk_t *m;
- register int len;
-
- if (buflen != 0)
- return 0;
- m = (mblk_t *)p;
- MINDEX(len, m, k);
- A = m->b_rptr[k];
- continue;
-#else
- return 0;
-#endif
- }
- A = p[k];
- continue;
-
- case BPF_LD|BPF_W|BPF_LEN:
- A = wirelen;
- continue;
-
- case BPF_LDX|BPF_W|BPF_LEN:
- X = wirelen;
- continue;
-
- case BPF_LD|BPF_W|BPF_IND:
- k = X + pc->k;
- if (k + sizeof(int) > buflen) {
-#ifdef _KERNEL
- int merr;
-
- if (buflen != 0)
- return 0;
- A = m_xword((mblk_t *)p, k, &merr);
- if (merr != 0)
- return 0;
- continue;
-#else
- return 0;
-#endif
- }
- A = EXTRACT_LONG(&p[k]);
- continue;
-
- case BPF_LD|BPF_H|BPF_IND:
- k = X + pc->k;
- if (k + sizeof(short int) > buflen) {
-#ifdef _KERNEL
- int merr;
-
- if (buflen != 0)
- return 0;
- A = m_xhalf((mblk_t *)p, k, &merr);
- if (merr != 0)
- return 0;
- continue;
-#else
- return 0;
-#endif
- }
- A = EXTRACT_SHORT(&p[k]);
- continue;
-
- case BPF_LD|BPF_B|BPF_IND:
- k = X + pc->k;
- if (k >= buflen) {
-#ifdef _KERNEL
- register mblk_t *m;
- register int len;
-
- if (buflen != 0)
- return 0;
- m = (mblk_t *)p;
- MINDEX(len, m, k);
- A = m->b_rptr[k];
- continue;
-#else
- return 0;
-#endif
- }
- A = p[k];
- continue;
-
- case BPF_LDX|BPF_MSH|BPF_B:
- k = pc->k;
- if (k >= buflen) {
-#ifdef _KERNEL
- register mblk_t *m;
- register int len;
-
- if (buflen != 0)
- return 0;
- m = (mblk_t *)p;
- MINDEX(len, m, k);
- X = (m->b_rptr[k] & 0xf) << 2;
- continue;
-#else
- return 0;
-#endif
- }
- X = (p[pc->k] & 0xf) << 2;
- continue;
-
- case BPF_LD|BPF_IMM:
- A = pc->k;
- continue;
-
- case BPF_LDX|BPF_IMM:
- X = pc->k;
- continue;
-
- case BPF_LD|BPF_MEM:
- A = mem[pc->k];
- continue;
-
- case BPF_LDX|BPF_MEM:
- X = mem[pc->k];
- continue;
-
- case BPF_ST:
- mem[pc->k] = A;
- continue;
-
- case BPF_STX:
- mem[pc->k] = X;
- continue;
-
- case BPF_JMP|BPF_JA:
- pc += pc->k;
- continue;
-
- case BPF_JMP|BPF_JGT|BPF_K:
- pc += (A > pc->k) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JGE|BPF_K:
- pc += (A >= pc->k) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JEQ|BPF_K:
- pc += (A == pc->k) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JSET|BPF_K:
- pc += (A & pc->k) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JGT|BPF_X:
- pc += (A > X) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JGE|BPF_X:
- pc += (A >= X) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JEQ|BPF_X:
- pc += (A == X) ? pc->jt : pc->jf;
- continue;
-
- case BPF_JMP|BPF_JSET|BPF_X:
- pc += (A & X) ? pc->jt : pc->jf;
- continue;
-
- case BPF_ALU|BPF_ADD|BPF_X:
- A += X;
- continue;
-
- case BPF_ALU|BPF_SUB|BPF_X:
- A -= X;
- continue;
-
- case BPF_ALU|BPF_MUL|BPF_X:
- A *= X;
- continue;
-
- case BPF_ALU|BPF_DIV|BPF_X:
- if (X == 0)
- return 0;
- A /= X;
- continue;
-
- case BPF_ALU|BPF_AND|BPF_X:
- A &= X;
- continue;
-
- case BPF_ALU|BPF_OR|BPF_X:
- A |= X;
- continue;
-
- case BPF_ALU|BPF_LSH|BPF_X:
- A <<= X;
- continue;
-
- case BPF_ALU|BPF_RSH|BPF_X:
- A >>= X;
- continue;
-
- case BPF_ALU|BPF_ADD|BPF_K:
- A += pc->k;
- continue;
-
- case BPF_ALU|BPF_SUB|BPF_K:
- A -= pc->k;
- continue;
-
- case BPF_ALU|BPF_MUL|BPF_K:
- A *= pc->k;
- continue;
-
- case BPF_ALU|BPF_DIV|BPF_K:
- A /= pc->k;
- continue;
-
- case BPF_ALU|BPF_AND|BPF_K:
- A &= pc->k;
- continue;
-
- case BPF_ALU|BPF_OR|BPF_K:
- A |= pc->k;
- continue;
-
- case BPF_ALU|BPF_LSH|BPF_K:
- A <<= pc->k;
- continue;
-
- case BPF_ALU|BPF_RSH|BPF_K:
- A >>= pc->k;
- continue;
-
- case BPF_ALU|BPF_NEG:
- A = -A;
- continue;
-
- case BPF_MISC|BPF_TAX:
- X = A;
- continue;
-
- case BPF_MISC|BPF_TXA:
- A = X;
- continue;
- }
- }
-}
-
-#ifdef _KERNEL
-/*
- * Return true if the 'fcode' is a valid filter program.
- * The constraints are that each jump be forward and to a valid
- * code. The code must terminate with either an accept or reject.
- * 'valid' is an array for use by the routine (it must be at least
- * 'len' bytes long).
- *
- * The kernel needs to be able to verify an application's filter code.
- * Otherwise, a bogus program could easily crash the system.
- */
-int
-bpf_validate(f, len)
- struct bpf_insn *f;
- int len;
-{
- register int i;
- register struct bpf_insn *p;
-
- for (i = 0; i < len; ++i) {
- /*
- * Check that that jumps are forward, and within
- * the code block.
- */
- p = &f[i];
- if (BPF_CLASS(p->code) == BPF_JMP) {
- register int from = i + 1;
-
- if (BPF_OP(p->code) == BPF_JA) {
- if (from + p->k >= len)
- return 0;
- }
- else if (from + p->jt >= len || from + p->jf >= len)
- return 0;
- }
- /*
- * Check that memory operations use valid addresses.
- */
- if ((BPF_CLASS(p->code) == BPF_ST ||
- (BPF_CLASS(p->code) == BPF_LD &&
- (p->code & 0xe0) == BPF_MEM)) &&
- (p->k >= BPF_MEMWORDS || p->k < 0))
- return 0;
- /*
- * Check for constant division by 0.
- */
- if (p->code == (BPF_ALU|BPF_DIV|BPF_K) && p->k == 0)
- return 0;
- }
- return BPF_CLASS(f[len - 1].code) == BPF_RET;
-}
-#endif
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