diff options
Diffstat (limited to 'package/etrax-tools/src/e100boot/libpcap-0.4/bpf/net/bpf_filter.c')
| -rw-r--r-- | package/etrax-tools/src/e100boot/libpcap-0.4/bpf/net/bpf_filter.c | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/package/etrax-tools/src/e100boot/libpcap-0.4/bpf/net/bpf_filter.c b/package/etrax-tools/src/e100boot/libpcap-0.4/bpf/net/bpf_filter.c new file mode 100644 index 000000000..d3dcc689a --- /dev/null +++ b/package/etrax-tools/src/e100boot/libpcap-0.4/bpf/net/bpf_filter.c @@ -0,0 +1,532 @@ +/*- + * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 + * 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. + * + * @(#)bpf.c 7.5 (Berkeley) 7/15/91 + */ + +#if !(defined(lint) || defined(KERNEL)) +static const char rcsid[] = + "@(#) $Header: /usr/local/cvs/linux/tools/build/e100boot/libpcap-0.4/bpf/net/bpf_filter.c,v 1.1 1999/08/26 10:07:57 johana Exp $ (LBL)"; +#endif + +#include <sys/param.h> +#include <sys/types.h> +#include <sys/time.h> +#include <net/bpf.h> + +#ifndef KERNEL +#include <stdlib.h> +#endif + +#define int32 bpf_int32 +#define u_int32 bpf_u_int32 + +#ifndef LBL_ALIGN +#if defined(sparc) || defined(mips) || defined(ibm032) || \ + defined(__alpha) || defined(__hpux) +#define LBL_ALIGN +#endif +#endif + +#ifndef LBL_ALIGN +#include <netinet/in.h> + +#define EXTRACT_SHORT(p) ((u_short)ntohs(*(u_short *)p)) +#define EXTRACT_LONG(p) (ntohl(*(u_int32 *)p)) +#else +#define EXTRACT_SHORT(p)\ + ((u_short)\ + ((u_short)*((u_char *)p+0)<<8|\ + (u_short)*((u_char *)p+1)<<0)) +#define EXTRACT_LONG(p)\ + ((u_int32)*((u_char *)p+0)<<24|\ + (u_int32)*((u_char *)p+1)<<16|\ + (u_int32)*((u_char *)p+2)<<8|\ + (u_int32)*((u_char *)p+3)<<0) +#endif + +#ifdef KERNEL +#include <sys/mbuf.h> +#define MINDEX(len, m, k) \ +{ \ + len = m->m_len; \ + while (k >= len) { \ + k -= len; \ + m = m->m_next; \ + if (m == 0) \ + return 0; \ + len = m->m_len; \ + } \ +} + +static int +m_xword(m, k, err) + register struct mbuf *m; + register int k, *err; +{ + register int len; + register u_char *cp, *np; + register struct mbuf *m0; + + MINDEX(len, m, k); + cp = mtod(m, u_char *) + k; + if (len - k >= 4) { + *err = 0; + return EXTRACT_LONG(cp); + } + m0 = m->m_next; + if (m0 == 0 || m0->m_len + len - k < 4) + goto bad; + *err = 0; + np = mtod(m0, u_char *); + 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 struct mbuf *m; + register int k, *err; +{ + register int len; + register u_char *cp; + register struct mbuf *m0; + + MINDEX(len, m, k); + cp = mtod(m, u_char *) + k; + if (len - k >= 2) { + *err = 0; + return EXTRACT_SHORT(cp); + } + m0 = m->m_next; + if (m0 == 0) + goto bad; + *err = 0; + return (cp[0] << 8) | mtod(m0, u_char *)[0]; + bad: + *err = 1; + return 0; +} +#endif + +/* + * 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 + */ +u_int +bpf_filter(pc, p, wirelen, buflen) + register struct bpf_insn *pc; + register u_char *p; + u_int wirelen; + register u_int buflen; +{ + register u_int32 A, X; + register int k; + int32 mem[BPF_MEMWORDS]; + + if (pc == 0) + /* + * No filter means accept all. + */ + return (u_int)-1; + A = 0; + X = 0; + --pc; + while (1) { + ++pc; + switch (pc->code) { + + default: +#ifdef KERNEL + return 0; +#else + abort(); +#endif + case BPF_RET|BPF_K: + return (u_int)pc->k; + + case BPF_RET|BPF_A: + return (u_int)A; + + case BPF_LD|BPF_W|BPF_ABS: + k = pc->k; + if (k + sizeof(int32) > buflen) { +#ifdef KERNEL + int merr; + + if (buflen != 0) + return 0; + A = m_xword((struct mbuf *)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) > buflen) { +#ifdef KERNEL + int merr; + + if (buflen != 0) + return 0; + A = m_xhalf((struct mbuf *)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 struct mbuf *m; + register int len; + + if (buflen != 0) + return 0; + m = (struct mbuf *)p; + MINDEX(len, m, k); + A = mtod(m, u_char *)[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(int32) > buflen) { +#ifdef KERNEL + int merr; + + if (buflen != 0) + return 0; + A = m_xword((struct mbuf *)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) > buflen) { +#ifdef KERNEL + int merr; + + if (buflen != 0) + return 0; + A = m_xhalf((struct mbuf *)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 struct mbuf *m; + register int len; + + if (buflen != 0) + return 0; + m = (struct mbuf *)p; + MINDEX(len, m, k); + A = mtod(m, u_char *)[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 struct mbuf *m; + register int len; + + if (buflen != 0) + return 0; + m = (struct mbuf *)p; + MINDEX(len, m, k); + X = (mtod(m, char *)[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 >= (unsigned)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 |