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authormcr <mcr>1999-10-07 23:46:40 +0000
committermcr <mcr>1999-10-07 23:46:40 +0000
commitb11ddf8a9b0d30bf759abf01afcf2894e79857b1 (patch)
tree5e15f6638915dde6ec02702ea6a5a0974894d4d4 /bpf
Initial revision
Diffstat (limited to 'bpf')
-rw-r--r--bpf/net/bpf.h264
-rw-r--r--bpf/net/bpf_filter.c532
2 files changed, 796 insertions, 0 deletions
diff --git a/bpf/net/bpf.h b/bpf/net/bpf.h
new file mode 100644
index 0000000..8d5cd9f
--- /dev/null
+++ b/bpf/net/bpf.h
@@ -0,0 +1,264 @@
+/*-
+ * 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.h 7.1 (Berkeley) 5/7/91
+ *
+ * @(#) $Header: /tcpdump/master/libpcap/bpf/net/Attic/bpf.h,v 1.36 1999-10-07 23:46:41 mcr Exp $ (LBL)
+ */
+
+#ifndef BPF_MAJOR_VERSION
+
+/* BSD style release date */
+#define BPF_RELEASE 199606
+
+typedef int bpf_int32;
+typedef u_int bpf_u_int32;
+
+/*
+ * Alignment macros. BPF_WORDALIGN rounds up to the next
+ * even multiple of BPF_ALIGNMENT.
+ */
+#define BPF_ALIGNMENT sizeof(bpf_int32)
+#define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
+
+#define BPF_MAXINSNS 512
+#define BPF_MAXBUFSIZE 0x8000
+#define BPF_MINBUFSIZE 32
+
+/*
+ * Structure for BIOCSETF.
+ */
+struct bpf_program {
+ u_int bf_len;
+ struct bpf_insn *bf_insns;
+};
+
+/*
+ * Struct returned by BIOCGSTATS.
+ */
+struct bpf_stat {
+ u_int bs_recv; /* number of packets received */
+ u_int bs_drop; /* number of packets dropped */
+};
+
+/*
+ * Struct return by BIOCVERSION. This represents the version number of
+ * the filter language described by the instruction encodings below.
+ * bpf understands a program iff kernel_major == filter_major &&
+ * kernel_minor >= filter_minor, that is, if the value returned by the
+ * running kernel has the same major number and a minor number equal
+ * equal to or less than the filter being downloaded. Otherwise, the
+ * results are undefined, meaning an error may be returned or packets
+ * may be accepted haphazardly.
+ * It has nothing to do with the source code version.
+ */
+struct bpf_version {
+ u_short bv_major;
+ u_short bv_minor;
+};
+/* Current version number of filter architecture. */
+#define BPF_MAJOR_VERSION 1
+#define BPF_MINOR_VERSION 1
+
+/*
+ * BPF ioctls
+ *
+ * The first set is for compatibility with Sun's pcc style
+ * header files. If your using gcc, we assume that you
+ * have run fixincludes so the latter set should work.
+ */
+#if (defined(sun) || defined(ibm032)) && !defined(__GNUC__)
+#define BIOCGBLEN _IOR(B,102, u_int)
+#define BIOCSBLEN _IOWR(B,102, u_int)
+#define BIOCSETF _IOW(B,103, struct bpf_program)
+#define BIOCFLUSH _IO(B,104)
+#define BIOCPROMISC _IO(B,105)
+#define BIOCGDLT _IOR(B,106, u_int)
+#define BIOCGETIF _IOR(B,107, struct ifreq)
+#define BIOCSETIF _IOW(B,108, struct ifreq)
+#define BIOCSRTIMEOUT _IOW(B,109, struct timeval)
+#define BIOCGRTIMEOUT _IOR(B,110, struct timeval)
+#define BIOCGSTATS _IOR(B,111, struct bpf_stat)
+#define BIOCIMMEDIATE _IOW(B,112, u_int)
+#define BIOCVERSION _IOR(B,113, struct bpf_version)
+#define BIOCSTCPF _IOW(B,114, struct bpf_program)
+#define BIOCSUDPF _IOW(B,115, struct bpf_program)
+#else
+#define BIOCGBLEN _IOR('B',102, u_int)
+#define BIOCSBLEN _IOWR('B',102, u_int)
+#define BIOCSETF _IOW('B',103, struct bpf_program)
+#define BIOCFLUSH _IO('B',104)
+#define BIOCPROMISC _IO('B',105)
+#define BIOCGDLT _IOR('B',106, u_int)
+#define BIOCGETIF _IOR('B',107, struct ifreq)
+#define BIOCSETIF _IOW('B',108, struct ifreq)
+#define BIOCSRTIMEOUT _IOW('B',109, struct timeval)
+#define BIOCGRTIMEOUT _IOR('B',110, struct timeval)
+#define BIOCGSTATS _IOR('B',111, struct bpf_stat)
+#define BIOCIMMEDIATE _IOW('B',112, u_int)
+#define BIOCVERSION _IOR('B',113, struct bpf_version)
+#define BIOCSTCPF _IOW('B',114, struct bpf_program)
+#define BIOCSUDPF _IOW('B',115, struct bpf_program)
+#endif
+
+/*
+ * Structure prepended to each packet.
+ */
+struct bpf_hdr {
+ struct timeval bh_tstamp; /* time stamp */
+ bpf_u_int32 bh_caplen; /* length of captured portion */
+ bpf_u_int32 bh_datalen; /* original length of packet */
+ u_short bh_hdrlen; /* length of bpf header (this struct
+ plus alignment padding) */
+};
+/*
+ * Because the structure above is not a multiple of 4 bytes, some compilers
+ * will insist on inserting padding; hence, sizeof(struct bpf_hdr) won't work.
+ * Only the kernel needs to know about it; applications use bh_hdrlen.
+ */
+#ifdef KERNEL
+#define SIZEOF_BPF_HDR 18
+#endif
+
+/*
+ * Data-link level type codes.
+ */
+#define DLT_NULL 0 /* no link-layer encapsulation */
+#define DLT_EN10MB 1 /* Ethernet (10Mb) */
+#define DLT_EN3MB 2 /* Experimental Ethernet (3Mb) */
+#define DLT_AX25 3 /* Amateur Radio AX.25 */
+#define DLT_PRONET 4 /* Proteon ProNET Token Ring */
+#define DLT_CHAOS 5 /* Chaos */
+#define DLT_IEEE802 6 /* IEEE 802 Networks */
+#define DLT_ARCNET 7 /* ARCNET */
+#define DLT_SLIP 8 /* Serial Line IP */
+#define DLT_PPP 9 /* Point-to-point Protocol */
+#define DLT_FDDI 10 /* FDDI */
+#define DLT_ATM_RFC1483 11 /* LLC/SNAP encapsulated atm */
+#define DLT_RAW 12 /* raw IP */
+#define DLT_SLIP_BSDOS 13 /* BSD/OS Serial Line IP */
+#define DLT_PPP_BSDOS 14 /* BSD/OS Point-to-point Protocol */
+
+/*
+ * The instruction encondings.
+ */
+/* instruction classes */
+#define BPF_CLASS(code) ((code) & 0x07)
+#define BPF_LD 0x00
+#define BPF_LDX 0x01
+#define BPF_ST 0x02
+#define BPF_STX 0x03
+#define BPF_ALU 0x04
+#define BPF_JMP 0x05
+#define BPF_RET 0x06
+#define BPF_MISC 0x07
+
+/* ld/ldx fields */
+#define BPF_SIZE(code) ((code) & 0x18)
+#define BPF_W 0x00
+#define BPF_H 0x08
+#define BPF_B 0x10
+#define BPF_MODE(code) ((code) & 0xe0)
+#define BPF_IMM 0x00
+#define BPF_ABS 0x20
+#define BPF_IND 0x40
+#define BPF_MEM 0x60
+#define BPF_LEN 0x80
+#define BPF_MSH 0xa0
+
+/* alu/jmp fields */
+#define BPF_OP(code) ((code) & 0xf0)
+#define BPF_ADD 0x00
+#define BPF_SUB 0x10
+#define BPF_MUL 0x20
+#define BPF_DIV 0x30
+#define BPF_OR 0x40
+#define BPF_AND 0x50
+#define BPF_LSH 0x60
+#define BPF_RSH 0x70
+#define BPF_NEG 0x80
+#define BPF_JA 0x00
+#define BPF_JEQ 0x10
+#define BPF_JGT 0x20
+#define BPF_JGE 0x30
+#define BPF_JSET 0x40
+#define BPF_SRC(code) ((code) & 0x08)
+#define BPF_K 0x00
+#define BPF_X 0x08
+
+/* ret - BPF_K and BPF_X also apply */
+#define BPF_RVAL(code) ((code) & 0x18)
+#define BPF_A 0x10
+
+/* misc */
+#define BPF_MISCOP(code) ((code) & 0xf8)
+#define BPF_TAX 0x00
+#define BPF_TXA 0x80
+
+/*
+ * The instruction data structure.
+ */
+struct bpf_insn {
+ u_short code;
+ u_char jt;
+ u_char jf;
+ bpf_int32 k;
+};
+
+/*
+ * Macros for insn array initializers.
+ */
+#define BPF_STMT(code, k) { (u_short)(code), 0, 0, k }
+#define BPF_JUMP(code, k, jt, jf) { (u_short)(code), jt, jf, k }
+
+#ifdef KERNEL
+extern u_int bpf_filter();
+extern void bpfattach();
+extern void bpf_tap();
+extern void bpf_mtap();
+#else
+#if __STDC__
+extern u_int bpf_filter(struct bpf_insn *, u_char *, u_int, u_int);
+#endif
+#endif
+
+/*
+ * Number of scratch memory words (for BPF_LD|BPF_MEM and BPF_ST).
+ */
+#define BPF_MEMWORDS 16
+
+#endif
diff --git a/bpf/net/bpf_filter.c b/bpf/net/bpf_filter.c
new file mode 100644
index 0000000..b82fcf5
--- /dev/null
+++ b/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: /tcpdump/master/libpcap/bpf/net/bpf_filter.c,v 1.33 1999-10-07 23:46:41 mcr 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