tools: rename tools/net directory to tools/bpf

We currently only have BPF tools in the tools/net directory.
We are about to add more BPF tools there, not necessarily
networking related, rename the directory and related Makefile
targets to bpf.

Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 2656 insertions, 0 deletions

diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
new file mode 100644
index 000000000000..ddf888010652
--- /dev/null
+++ b/tools/bpf/Makefile
@@ -0,0 +1,35 @@
+prefix = /usr
+
+CC = gcc
+LEX = flex
+YACC = bison
+
+CFLAGS += -Wall -O2
+CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
+
+%.yacc.c: %.y
+	$(YACC) -o $@ -d $<
+
+%.lex.c: %.l
+	$(LEX) -o $@ $<
+
+all : bpf_jit_disasm bpf_dbg bpf_asm
+
+bpf_jit_disasm : CFLAGS += -DPACKAGE='bpf_jit_disasm'
+bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl
+bpf_jit_disasm : bpf_jit_disasm.o
+
+bpf_dbg : LDLIBS = -lreadline
+bpf_dbg : bpf_dbg.o
+
+bpf_asm : LDLIBS =
+bpf_asm : bpf_asm.o bpf_exp.yacc.o bpf_exp.lex.o
+bpf_exp.lex.o : bpf_exp.yacc.c
+
+clean :
+	rm -rf *.o bpf_jit_disasm bpf_dbg bpf_asm bpf_exp.yacc.* bpf_exp.lex.*
+
+install :
+	install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm
+	install bpf_dbg $(prefix)/bin/bpf_dbg
+	install bpf_asm $(prefix)/bin/bpf_asm
diff --git a/tools/bpf/bpf_asm.c b/tools/bpf/bpf_asm.c
new file mode 100644
index 000000000000..c15aef097b04
--- /dev/null
+++ b/tools/bpf/bpf_asm.c
@@ -0,0 +1,52 @@
+/*
+ * Minimal BPF assembler
+ *
+ * Instead of libpcap high-level filter expressions, it can be quite
+ * useful to define filters in low-level BPF assembler (that is kept
+ * close to Steven McCanne and Van Jacobson's original BPF paper).
+ * In particular for BPF JIT implementors, JIT security auditors, or
+ * just for defining BPF expressions that contain extensions which are
+ * not supported by compilers.
+ *
+ * How to get into it:
+ *
+ * 1) read Documentation/networking/filter.txt
+ * 2) Run `bpf_asm [-c] <filter-prog file>` to translate into binary
+ *    blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will
+ *    pretty print a C-like construct.
+ *
+ * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+extern void bpf_asm_compile(FILE *fp, bool cstyle);
+
+int main(int argc, char **argv)
+{
+	FILE *fp = stdin;
+	bool cstyle = false;
+	int i;
+
+	for (i = 1; i < argc; i++) {
+		if (!strncmp("-c", argv[i], 2)) {
+			cstyle = true;
+			continue;
+		}
+
+		fp = fopen(argv[i], "r");
+		if (!fp) {
+			fp = stdin;
+			continue;
+		}
+
+		break;
+	}
+
+	bpf_asm_compile(fp, cstyle);
+
+	return 0;
+}
diff --git a/tools/bpf/bpf_dbg.c b/tools/bpf/bpf_dbg.c
new file mode 100644
index 000000000000..4f254bcc4423
--- /dev/null
+++ b/tools/bpf/bpf_dbg.c
@@ -0,0 +1,1395 @@
+/*
+ * Minimal BPF debugger
+ *
+ * Minimal BPF debugger that mimics the kernel's engine (w/o extensions)
+ * and allows for single stepping through selected packets from a pcap
+ * with a provided user filter in order to facilitate verification of a
+ * BPF program. Besides others, this is useful to verify BPF programs
+ * before attaching to a live system, and can be used in socket filters,
+ * cls_bpf, xt_bpf, team driver and e.g. PTP code; in particular when a
+ * single more complex BPF program is being used. Reasons for a more
+ * complex BPF program are likely primarily to optimize execution time
+ * for making a verdict when multiple simple BPF programs are combined
+ * into one in order to prevent parsing same headers multiple times.
+ *
+ * More on how to debug BPF opcodes see Documentation/networking/filter.txt
+ * which is the main document on BPF. Mini howto for getting started:
+ *
+ *  1) `./bpf_dbg` to enter the shell (shell cmds denoted with '>'):
+ *  2) > load bpf 6,40 0 0 12,21 0 3 20... (output from `bpf_asm` or
+ *     `tcpdump -iem1 -ddd port 22 | tr '\n' ','` to load as filter)
+ *  3) > load pcap foo.pcap
+ *  4) > run <n>/disassemble/dump/quit (self-explanatory)
+ *  5) > breakpoint 2 (sets bp at loaded BPF insns 2, do `run` then;
+ *       multiple bps can be set, of course, a call to `breakpoint`
+ *       w/o args shows currently loaded bps, `breakpoint reset` for
+ *       resetting all breakpoints)
+ *  6) > select 3 (`run` etc will start from the 3rd packet in the pcap)
+ *  7) > step [-<n>, +<n>] (performs single stepping through the BPF)
+ *
+ * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <setjmp.h>
+#include <linux/filter.h>
+#include <linux/if_packet.h>
+#include <readline/readline.h>
+#include <readline/history.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <arpa/inet.h>
+#include <net/ethernet.h>
+
+#define TCPDUMP_MAGIC	0xa1b2c3d4
+
+#define BPF_LDX_B	(BPF_LDX | BPF_B)
+#define BPF_LDX_W	(BPF_LDX | BPF_W)
+#define BPF_JMP_JA	(BPF_JMP | BPF_JA)
+#define BPF_JMP_JEQ	(BPF_JMP | BPF_JEQ)
+#define BPF_JMP_JGT	(BPF_JMP | BPF_JGT)
+#define BPF_JMP_JGE	(BPF_JMP | BPF_JGE)
+#define BPF_JMP_JSET	(BPF_JMP | BPF_JSET)
+#define BPF_ALU_ADD	(BPF_ALU | BPF_ADD)
+#define BPF_ALU_SUB	(BPF_ALU | BPF_SUB)
+#define BPF_ALU_MUL	(BPF_ALU | BPF_MUL)
+#define BPF_ALU_DIV	(BPF_ALU | BPF_DIV)
+#define BPF_ALU_MOD	(BPF_ALU | BPF_MOD)
+#define BPF_ALU_NEG	(BPF_ALU | BPF_NEG)
+#define BPF_ALU_AND	(BPF_ALU | BPF_AND)
+#define BPF_ALU_OR	(BPF_ALU | BPF_OR)
+#define BPF_ALU_XOR	(BPF_ALU | BPF_XOR)
+#define BPF_ALU_LSH	(BPF_ALU | BPF_LSH)
+#define BPF_ALU_RSH	(BPF_ALU | BPF_RSH)
+#define BPF_MISC_TAX	(BPF_MISC | BPF_TAX)
+#define BPF_MISC_TXA	(BPF_MISC | BPF_TXA)
+#define BPF_LD_B	(BPF_LD | BPF_B)
+#define BPF_LD_H	(BPF_LD | BPF_H)
+#define BPF_LD_W	(BPF_LD | BPF_W)
+
+#ifndef array_size
+# define array_size(x)	(sizeof(x) / sizeof((x)[0]))
+#endif
+
+#ifndef __check_format_printf
+# define __check_format_printf(pos_fmtstr, pos_fmtargs) \
+	__attribute__ ((format (printf, (pos_fmtstr), (pos_fmtargs))))
+#endif
+
+enum {
+	CMD_OK,
+	CMD_ERR,
+	CMD_EX,
+};
+
+struct shell_cmd {
+	const char *name;
+	int (*func)(char *args);
+};
+
+struct pcap_filehdr {
+	uint32_t magic;
+	uint16_t version_major;
+	uint16_t version_minor;
+	int32_t  thiszone;
+	uint32_t sigfigs;
+	uint32_t snaplen;
+	uint32_t linktype;
+};
+
+struct pcap_timeval {
+	int32_t tv_sec;
+	int32_t tv_usec;
+};
+
+struct pcap_pkthdr {
+	struct pcap_timeval ts;
+	uint32_t caplen;
+	uint32_t len;
+};
+
+struct bpf_regs {
+	uint32_t A;
+	uint32_t X;
+	uint32_t M[BPF_MEMWORDS];
+	uint32_t R;
+	bool     Rs;
+	uint16_t Pc;
+};
+
+static struct sock_filter bpf_image[BPF_MAXINSNS + 1];
+static unsigned int bpf_prog_len;
+
+static int bpf_breakpoints[64];
+static struct bpf_regs bpf_regs[BPF_MAXINSNS + 1];
+static struct bpf_regs bpf_curr;
+static unsigned int bpf_regs_len;
+
+static int pcap_fd = -1;
+static unsigned int pcap_packet;
+static size_t pcap_map_size;
+static char *pcap_ptr_va_start, *pcap_ptr_va_curr;
+
+static const char * const op_table[] = {
+	[BPF_ST]	= "st",
+	[BPF_STX]	= "stx",
+	[BPF_LD_B]	= "ldb",
+	[BPF_LD_H]	= "ldh",
+	[BPF_LD_W]	= "ld",
+	[BPF_LDX]	= "ldx",
+	[BPF_LDX_B]	= "ldxb",
+	[BPF_JMP_JA]	= "ja",
+	[BPF_JMP_JEQ]	= "jeq",
+	[BPF_JMP_JGT]	= "jgt",
+	[BPF_JMP_JGE]	= "jge",
+	[BPF_JMP_JSET]	= "jset",
+	[BPF_ALU_ADD]	= "add",
+	[BPF_ALU_SUB]	= "sub",
+	[BPF_ALU_MUL]	= "mul",
+	[BPF_ALU_DIV]	= "div",
+	[BPF_ALU_MOD]	= "mod",
+	[BPF_ALU_NEG]	= "neg",
+	[BPF_ALU_AND]	= "and",
+	[BPF_ALU_OR]	= "or",
+	[BPF_ALU_XOR]	= "xor",
+	[BPF_ALU_LSH]	= "lsh",
+	[BPF_ALU_RSH]	= "rsh",
+	[BPF_MISC_TAX]	= "tax",
+	[BPF_MISC_TXA]	= "txa",
+	[BPF_RET]	= "ret",
+};
+
+static __check_format_printf(1, 2) int rl_printf(const char *fmt, ...)
+{
+	int ret;
+	va_list vl;
+
+	va_start(vl, fmt);
+	ret = vfprintf(rl_outstream, fmt, vl);
+	va_end(vl);
+
+	return ret;
+}
+
+static int matches(const char *cmd, const char *pattern)
+{
+	int len = strlen(cmd);
+
+	if (len > strlen(pattern))
+		return -1;
+
+	return memcmp(pattern, cmd, len);
+}
+
+static void hex_dump(const uint8_t *buf, size_t len)
+{
+	int i;
+
+	rl_printf("%3u: ", 0);
+	for (i = 0; i < len; i++) {
+		if (i && !(i % 16))
+			rl_printf("\n%3u: ", i);
+		rl_printf("%02x ", buf[i]);
+	}
+	rl_printf("\n");
+}
+
+static bool bpf_prog_loaded(void)
+{
+	if (bpf_prog_len == 0)
+		rl_printf("no bpf program loaded!\n");
+
+	return bpf_prog_len > 0;
+}
+
+static void bpf_disasm(const struct sock_filter f, unsigned int i)
+{
+	const char *op, *fmt;
+	int val = f.k;
+	char buf[256];
+
+	switch (f.code) {
+	case BPF_RET | BPF_K:
+		op = op_table[BPF_RET];
+		fmt = "#%#x";
+		break;
+	case BPF_RET | BPF_A:
+		op = op_table[BPF_RET];
+		fmt = "a";
+		break;
+	case BPF_RET | BPF_X:
+		op = op_table[BPF_RET];
+		fmt = "x";
+		break;
+	case BPF_MISC_TAX:
+		op = op_table[BPF_MISC_TAX];
+		fmt = "";
+		break;
+	case BPF_MISC_TXA:
+		op = op_table[BPF_MISC_TXA];
+		fmt = "";
+		break;
+	case BPF_ST:
+		op = op_table[BPF_ST];
+		fmt = "M[%d]";
+		break;
+	case BPF_STX:
+		op = op_table[BPF_STX];
+		fmt = "M[%d]";
+		break;
+	case BPF_LD_W | BPF_ABS:
+		op = op_table[BPF_LD_W];
+		fmt = "[%d]";
+		break;
+	case BPF_LD_H | BPF_ABS:
+		op = op_table[BPF_LD_H];
+		fmt = "[%d]";
+		break;
+	case BPF_LD_B | BPF_ABS:
+		op = op_table[BPF_LD_B];
+		fmt = "[%d]";
+		break;
+	case BPF_LD_W | BPF_LEN:
+		op = op_table[BPF_LD_W];
+		fmt = "#len";
+		break;
+	case BPF_LD_W | BPF_IND:
+		op = op_table[BPF_LD_W];
+		fmt = "[x+%d]";
+		break;
+	case BPF_LD_H | BPF_IND:
+		op = op_table[BPF_LD_H];
+		fmt = "[x+%d]";
+		break;
+	case BPF_LD_B | BPF_IND:
+		op = op_table[BPF_LD_B];
+		fmt = "[x+%d]";
+		break;
+	case BPF_LD | BPF_IMM:
+		op = op_table[BPF_LD_W];
+		fmt = "#%#x";
+		break;
+	case BPF_LDX | BPF_IMM:
+		op = op_table[BPF_LDX];
+		fmt = "#%#x";
+		break;
+	case BPF_LDX_B | BPF_MSH:
+		op = op_table[BPF_LDX_B];
+		fmt = "4*([%d]&0xf)";
+		break;
+	case BPF_LD | BPF_MEM:
+		op = op_table[BPF_LD_W];
+		fmt = "M[%d]";
+		break;
+	case BPF_LDX | BPF_MEM:
+		op = op_table[BPF_LDX];
+		fmt = "M[%d]";
+		break;
+	case BPF_JMP_JA:
+		op = op_table[BPF_JMP_JA];
+		fmt = "%d";
+		val = i + 1 + f.k;
+		break;
+	case BPF_JMP_JGT | BPF_X:
+		op = op_table[BPF_JMP_JGT];
+		fmt = "x";
+		break;
+	case BPF_JMP_JGT | BPF_K:
+		op = op_table[BPF_JMP_JGT];
+		fmt = "#%#x";
+		break;
+	case BPF_JMP_JGE | BPF_X:
+		op = op_table[BPF_JMP_JGE];
+		fmt = "x";
+		break;
+	case BPF_JMP_JGE | BPF_K:
+		op = op_table[BPF_JMP_JGE];
+		fmt = "#%#x";
+		break;
+	case BPF_JMP_JEQ | BPF_X:
+		op = op_table[BPF_JMP_JEQ];
+		fmt = "x";
+		break;
+	case BPF_JMP_JEQ | BPF_K:
+		op = op_table[BPF_JMP_JEQ];
+		fmt = "#%#x";
+		break;
+	case BPF_JMP_JSET | BPF_X:
+		op = op_table[BPF_JMP_JSET];
+		fmt = "x";
+		break;
+	case BPF_JMP_JSET | BPF_K:
+		op = op_table[BPF_JMP_JSET];
+		fmt = "#%#x";
+		break;
+	case BPF_ALU_NEG:
+		op = op_table[BPF_ALU_NEG];
+		fmt = "";
+		break;
+	case BPF_ALU_LSH | BPF_X:
+		op = op_table[BPF_ALU_LSH];
+		fmt = "x";
+		break;
+	case BPF_ALU_LSH | BPF_K:
+		op = op_table[BPF_ALU_LSH];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_RSH | BPF_X:
+		op = op_table[BPF_ALU_RSH];
+		fmt = "x";
+		break;
+	case BPF_ALU_RSH | BPF_K:
+		op = op_table[BPF_ALU_RSH];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_ADD | BPF_X:
+		op = op_table[BPF_ALU_ADD];
+		fmt = "x";
+		break;
+	case BPF_ALU_ADD | BPF_K:
+		op = op_table[BPF_ALU_ADD];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_SUB | BPF_X:
+		op = op_table[BPF_ALU_SUB];
+		fmt = "x";
+		break;
+	case BPF_ALU_SUB | BPF_K:
+		op = op_table[BPF_ALU_SUB];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_MUL | BPF_X:
+		op = op_table[BPF_ALU_MUL];
+		fmt = "x";
+		break;
+	case BPF_ALU_MUL | BPF_K:
+		op = op_table[BPF_ALU_MUL];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_DIV | BPF_X:
+		op = op_table[BPF_ALU_DIV];
+		fmt = "x";
+		break;
+	case BPF_ALU_DIV | BPF_K:
+		op = op_table[BPF_ALU_DIV];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_MOD | BPF_X:
+		op = op_table[BPF_ALU_MOD];
+		fmt = "x";
+		break;
+	case BPF_ALU_MOD | BPF_K:
+		op = op_table[BPF_ALU_MOD];
+		fmt = "#%d";
+		break;
+	case BPF_ALU_AND | BPF_X:
+		op = op_table[BPF_ALU_AND];
+		fmt = "x";
+		break;
+	case BPF_ALU_AND | BPF_K:
+		op = op_table[BPF_ALU_AND];
+		fmt = "#%#x";
+		break;
+	case BPF_ALU_OR | BPF_X:
+		op = op_table[BPF_ALU_OR];
+		fmt = "x";
+		break;
+	case BPF_ALU_OR | BPF_K:
+		op = op_table[BPF_ALU_OR];
+		fmt = "#%#x";
+		break;
+	case BPF_ALU_XOR | BPF_X:
+		op = op_table[BPF_ALU_XOR];
+		fmt = "x";
+		break;
+	case BPF_ALU_XOR | BPF_K:
+		op = op_table[BPF_ALU_XOR];
+		fmt = "#%#x";
+		break;
+	default:
+		op = "nosup";
+		fmt = "%#x";
+		val = f.code;
+		break;
+	}
+
+	memset(buf, 0, sizeof(buf));
+	snprintf(buf, sizeof(buf), fmt, val);
+	buf[sizeof(buf) - 1] = 0;
+
+	if ((BPF_CLASS(f.code) == BPF_JMP && BPF_OP(f.code) != BPF_JA))
+		rl_printf("l%d:\t%s %s, l%d, l%d\n", i, op, buf,
+			  i + 1 + f.jt, i + 1 + f.jf);
+	else
+		rl_printf("l%d:\t%s %s\n", i, op, buf);
+}
+
+static void bpf_dump_curr(struct bpf_regs *r, struct sock_filter *f)
+{
+	int i, m = 0;
+
+	rl_printf("pc:       [%u]\n", r->Pc);
+	rl_printf("code:     [%u] jt[%u] jf[%u] k[%u]\n",
+		  f->code, f->jt, f->jf, f->k);
+	rl_printf("curr:     ");
+	bpf_disasm(*f, r->Pc);
+
+	if (f->jt || f->jf) {
+		rl_printf("jt:       ");
+		bpf_disasm(*(f + f->jt + 1), r->Pc + f->jt + 1);
+		rl_printf("jf:       ");
+		bpf_disasm(*(f + f->jf + 1), r->Pc + f->jf + 1);
+	}
+
+	rl_printf("A:        [%#08x][%u]\n", r->A, r->A);
+	rl_printf("X:        [%#08x][%u]\n", r->X, r->X);
+	if (r->Rs)
+		rl_printf("ret:      [%#08x][%u]!\n", r->R, r->R);
+
+	for (i = 0; i < BPF_MEMWORDS; i++) {
+		if (r->M[i]) {
+			m++;
+			rl_printf("M[%d]: [%#08x][%u]\n", i, r->M[i], r->M[i]);
+		}
+	}
+	if (m == 0)
+		rl_printf("M[0,%d]:  [%#08x][%u]\n", BPF_MEMWORDS - 1, 0, 0);
+}
+
+static void bpf_dump_pkt(uint8_t *pkt, uint32_t pkt_caplen, uint32_t pkt_len)
+{
+	if (pkt_caplen != pkt_len)
+		rl_printf("cap: %u, len: %u\n", pkt_caplen, pkt_len);
+	else
+		rl_printf("len: %u\n", pkt_len);
+
+	hex_dump(pkt, pkt_caplen);
+}
+
+static void bpf_disasm_all(const struct sock_filter *f, unsigned int len)
+{
+	unsigned int i;
+
+	for (i = 0; i < len; i++)
+		bpf_disasm(f[i], i);
+}
+
+static void bpf_dump_all(const struct sock_filter *f, unsigned int len)
+{
+	unsigned int i;
+
+	rl_printf("/* { op, jt, jf, k }, */\n");
+	for (i = 0; i < len; i++)
+		rl_printf("{ %#04x, %2u, %2u, %#010x },\n",
+			  f[i].code, f[i].jt, f[i].jf, f[i].k);
+}
+
+static bool bpf_runnable(struct sock_filter *f, unsigned int len)
+{
+	int sock, ret, i;
+	struct sock_fprog bpf = {
+		.filter = f,
+		.len = len,
+	};
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock < 0) {
+		rl_printf("cannot open socket!\n");
+		return false;
+	}
+	ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf));
+	close(sock);
+	if (ret < 0) {
+		rl_printf("program not allowed to run by kernel!\n");
+		return false;
+	}
+	for (i = 0; i < len; i++) {
+		if (BPF_CLASS(f[i].code) == BPF_LD &&
+		    f[i].k > SKF_AD_OFF) {
+			rl_printf("extensions currently not supported!\n");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static void bpf_reset_breakpoints(void)
+{
+	int i;
+
+	for (i = 0; i < array_size(bpf_breakpoints); i++)
+		bpf_breakpoints[i] = -1;
+}
+
+static void bpf_set_breakpoints(unsigned int where)
+{
+	int i;
+	bool set = false;
+
+	for (i = 0; i < array_size(bpf_breakpoints); i++) {
+		if (bpf_breakpoints[i] == (int) where) {
+			rl_printf("breakpoint already set!\n");
+			set = true;
+			break;
+		}
+
+		if (bpf_breakpoints[i] == -1 && set == false) {
+			bpf_breakpoints[i] = where;
+			set = true;
+		}
+	}
+
+	if (!set)
+		rl_printf("too many breakpoints set, reset first!\n");
+}
+
+static void bpf_dump_breakpoints(void)
+{
+	int i;
+
+	rl_printf("breakpoints: ");
+
+	for (i = 0; i < array_size(bpf_breakpoints); i++) {
+		if (bpf_breakpoints[i] < 0)
+			continue;
+		rl_printf("%d ", bpf_breakpoints[i]);
+	}
+
+	rl_printf("\n");
+}
+
+static void bpf_reset(void)
+{
+	bpf_regs_len = 0;
+
+	memset(bpf_regs, 0, sizeof(bpf_regs));
+	memset(&bpf_curr, 0, sizeof(bpf_curr));
+}
+
+static void bpf_safe_regs(void)
+{
+	memcpy(&bpf_regs[bpf_regs_len++], &bpf_curr, sizeof(bpf_curr));
+}
+
+static bool bpf_restore_regs(int off)
+{
+	unsigned int index = bpf_regs_len - 1 + off;
+
+	if (index == 0) {
+		bpf_reset();
+		return true;
+	} else if (index < bpf_regs_len) {
+		memcpy(&bpf_curr, &bpf_regs[index], sizeof(bpf_curr));
+		bpf_regs_len = index;
+		return true;
+	} else {
+		rl_printf("reached bottom of register history stack!\n");
+		return false;
+	}
+}
+
+static uint32_t extract_u32(uint8_t *pkt, uint32_t off)
+{
+	uint32_t r;
+
+	memcpy(&r, &pkt[off], sizeof(r));
+
+	return ntohl(r);
+}
+
+static uint16_t extract_u16(uint8_t *pkt, uint32_t off)
+{
+	uint16_t r;
+
+	memcpy(&r, &pkt[off], sizeof(r));
+
+	return ntohs(r);
+}
+
+static uint8_t extract_u8(uint8_t *pkt, uint32_t off)
+{
+	return pkt[off];
+}
+
+static void set_return(struct bpf_regs *r)
+{
+	r->R = 0;
+	r->Rs = true;
+}
+
+static void bpf_single_step(struct bpf_regs *r, struct sock_filter *f,
+			    uint8_t *pkt, uint32_t pkt_caplen,
+			    uint32_t pkt_len)
+{
+	uint32_t K = f->k;
+	int d;
+
+	switch (f->code) {
+	case BPF_RET | BPF_K:
+		r->R = K;
+		r->Rs = true;
+		break;
+	case BPF_RET | BPF_A:
+		r->R = r->A;
+		r->Rs = true;
+		break;
+	case BPF_RET | BPF_X:
+		r->R = r->X;
+		r->Rs = true;
+		break;
+	case BPF_MISC_TAX:
+		r->X = r->A;
+		break;
+	case BPF_MISC_TXA:
+		r->A = r->X;
+		break;
+	case BPF_ST:
+		r->M[K] = r->A;
+		break;
+	case BPF_STX:
+		r->M[K] = r->X;
+		break;
+	case BPF_LD_W | BPF_ABS:
+		d = pkt_caplen - K;
+		if (d >= sizeof(uint32_t))
+			r->A = extract_u32(pkt, K);
+		else
+			set_return(r);
+		break;
+	case BPF_LD_H | BPF_ABS:
+		d = pkt_caplen - K;
+		if (d >= sizeof(uint16_t))
+			r->A = extract_u16(pkt, K);
+		else
+			set_return(r);
+		break;
+	case BPF_LD_B | BPF_ABS:
+		d = pkt_caplen - K;
+		if (d >= sizeof(uint8_t))
+			r->A = extract_u8(pkt, K);
+		else
+			set_return(r);
+		break;
+	case BPF_LD_W | BPF_IND:
+		d = pkt_caplen - (r->X + K);
+		if (d >= sizeof(uint32_t))
+			r->A = extract_u32(pkt, r->X + K);
+		break;
+	case BPF_LD_H | BPF_IND:
+		d = pkt_caplen - (r->X + K);
+		if (d >= sizeof(uint16_t))
+			r->A = extract_u16(pkt, r->X + K);
+		else
+			set_return(r);
+		break;
+	case BPF_LD_B | BPF_IND:
+		d = pkt_caplen - (r->X + K);
+		if (d >= sizeof(uint8_t))
+			r->A = extract_u8(pkt, r->X + K);
+		else
+			set_return(r);
+		break;
+	case BPF_LDX_B | BPF_MSH:
+		d = pkt_caplen - K;
+		if (d >= sizeof(uint8_t)) {
+			r->X = extract_u8(pkt, K);
+			r->X = (r->X & 0xf) << 2;
+		} else
+			set_return(r);
+		break;
+	case BPF_LD_W | BPF_LEN:
+		r->A = pkt_len;
+		break;
+	case BPF_LDX_W | BPF_LEN:
+		r->A = pkt_len;
+		break;
+	case BPF_LD | BPF_IMM:
+		r->A = K;
+		break;
+	case BPF_LDX | BPF_IMM:
+		r->X = K;
+		break;
+	case BPF_LD | BPF_MEM:
+		r->A = r->M[K];
+		break;
+	case BPF_LDX | BPF_MEM:
+		r->X = r->M[K];
+		break;
+	case BPF_JMP_JA:
+		r->Pc += K;
+		break;
+	case BPF_JMP_JGT | BPF_X:
+		r->Pc += r->A > r->X ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JGT | BPF_K:
+		r->Pc += r->A > K ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JGE | BPF_X:
+		r->Pc += r->A >= r->X ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JGE | BPF_K:
+		r->Pc += r->A >= K ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JEQ | BPF_X:
+		r->Pc += r->A == r->X ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JEQ | BPF_K:
+		r->Pc += r->A == K ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JSET | BPF_X:
+		r->Pc += r->A & r->X ? f->jt : f->jf;
+		break;
+	case BPF_JMP_JSET | BPF_K:
+		r->Pc += r->A & K ? f->jt : f->jf;
+		break;
+	case BPF_ALU_NEG:
+		r->A = -r->A;
+		break;
+	case BPF_ALU_LSH | BPF_X:
+		r->A <<= r->X;
+		break;
+	case BPF_ALU_LSH | BPF_K:
+		r->A <<= K;
+		break;
+	case BPF_ALU_RSH | BPF_X:
+		r->A >>= r->X;
+		break;
+	case BPF_ALU_RSH | BPF_K:
+		r->A >>= K;
+		break;
+	case BPF_ALU_ADD | BPF_X:
+		r->A += r->X;
+		break;
+	case BPF_ALU_ADD | BPF_K:
+		r->A += K;
+		break;
+	case BPF_ALU_SUB | BPF_X:
+		r->A -= r->X;
+		break;
+	case BPF_ALU_SUB | BPF_K:
+		r->A -= K;
+		break;
+	case BPF_ALU_MUL | BPF_X:
+		r->A *= r->X;
+		break;
+	case BPF_ALU_MUL | BPF_K:
+		r->A *= K;
+		break;
+	case BPF_ALU_DIV | BPF_X:
+	case BPF_ALU_MOD | BPF_X:
+		if (r->X == 0) {
+			set_return(r);
+			break;
+		}
+		goto do_div;
+	case BPF_ALU_DIV | BPF_K:
+	case BPF_ALU_MOD | BPF_K:
+		if (K == 0) {
+			set_return(r);
+			break;
+		}
+do_div:
+		switch (f->code) {
+		case BPF_ALU_DIV | BPF_X:
+			r->A /= r->X;
+			break;
+		case BPF_ALU_DIV | BPF_K:
+			r->A /= K;
+			break;
+		case BPF_ALU_MOD | BPF_X:
+			r->A %= r->X;
+			break;
+		case BPF_ALU_MOD | BPF_K:
+			r->A %= K;
+			break;
+		}
+		break;
+	case BPF_ALU_AND | BPF_X:
+		r->A &= r->X;
+		break;
+	case BPF_ALU_AND | BPF_K:
+		r->A &= K;
+		break;
+	case BPF_ALU_OR | BPF_X:
+		r->A |= r->X;
+		break;
+	case BPF_ALU_OR | BPF_K:
+		r->A |= K;
+		break;
+	case BPF_ALU_XOR | BPF_X:
+		r->A ^= r->X;
+		break;
+	case BPF_ALU_XOR | BPF_K:
+		r->A ^= K;
+		break;
+	}
+}
+
+static bool bpf_pc_has_breakpoint(uint16_t pc)
+{
+	int i;
+
+	for (i = 0; i < array_size(bpf_breakpoints); i++) {
+		if (bpf_breakpoints[i] < 0)
+			continue;
+		if (bpf_breakpoints[i] == pc)
+			return true;
+	}
+
+	return false;
+}
+
+static bool bpf_handle_breakpoint(struct bpf_regs *r, struct sock_filter *f,
+				  uint8_t *pkt, uint32_t pkt_caplen,
+				  uint32_t pkt_len)
+{
+	rl_printf("-- register dump --\n");
+	bpf_dump_curr(r, &f[r->Pc]);
+	rl_printf("-- packet dump --\n");
+	bpf_dump_pkt(pkt, pkt_caplen, pkt_len);
+	rl_printf("(breakpoint)\n");
+	return true;
+}
+
+static int bpf_run_all(struct sock_filter *f, uint16_t bpf_len, uint8_t *pkt,
+		       uint32_t pkt_caplen, uint32_t pkt_len)
+{
+	bool stop = false;
+
+	while (bpf_curr.Rs == false && stop == false) {
+		bpf_safe_regs();
+
+		if (bpf_pc_has_breakpoint(bpf_curr.Pc))
+			stop = bpf_handle_breakpoint(&bpf_curr, f, pkt,
+						     pkt_caplen, pkt_len);
+
+		bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen,
+				pkt_len);
+		bpf_curr.Pc++;
+	}
+
+	return stop ? -1 : bpf_curr.R;
+}
+
+static int bpf_run_stepping(struct sock_filter *f, uint16_t bpf_len,
+			    uint8_t *pkt, uint32_t pkt_caplen,
+			    uint32_t pkt_len, int next)
+{
+	bool stop = false;
+	int i = 1;
+
+	while (bpf_curr.Rs == false && stop == false) {
+		bpf_safe_regs();
+
+		if (i++ == next)
+			stop = bpf_handle_breakpoint(&bpf_curr, f, pkt,
+						     pkt_caplen, pkt_len);
+
+		bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen,
+				pkt_len);
+		bpf_curr.Pc++;
+	}
+
+	return stop ? -1 : bpf_curr.R;
+}
+
+static bool pcap_loaded(void)
+{
+	if (pcap_fd < 0)
+		rl_printf("no pcap file loaded!\n");
+
+	return pcap_fd >= 0;
+}
+
+static struct pcap_pkthdr *pcap_curr_pkt(void)
+{
+	return (void *) pcap_ptr_va_curr;
+}
+
+static bool pcap_next_pkt(void)
+{
+	struct pcap_pkthdr *hdr = pcap_curr_pkt();
+
+	if (pcap_ptr_va_curr + sizeof(*hdr) -
+	    pcap_ptr_va_start >= pcap_map_size)
+		return false;
+	if (hdr->caplen == 0 || hdr->len == 0 || hdr->caplen > hdr->len)
+		return false;
+	if (pcap_ptr_va_curr + sizeof(*hdr) + hdr->caplen -
+	    pcap_ptr_va_start >= pcap_map_size)
+		return false;
+
+	pcap_ptr_va_curr += (sizeof(*hdr) + hdr->caplen);
+	return true;
+}
+
+static void pcap_reset_pkt(void)
+{
+	pcap_ptr_va_curr = pcap_ptr_va_start + sizeof(struct pcap_filehdr);
+}
+
+static int try_load_pcap(const char *file)
+{
+	struct pcap_filehdr *hdr;
+	struct stat sb;
+	int ret;
+
+	pcap_fd = open(file, O_RDONLY);
+	if (pcap_fd < 0) {
+		rl_printf("cannot open pcap [%s]!\n", strerror(errno));
+		return CMD_ERR;
+	}
+
+	ret = fstat(pcap_fd, &sb);
+	if (ret < 0) {
+		rl_printf("cannot fstat pcap file!\n");
+		return CMD_ERR;
+	}
+
+	if (!S_ISREG(sb.st_mode)) {
+		rl_printf("not a regular pcap file, duh!\n");
+		return CMD_ERR;
+	}
+
+	pcap_map_size = sb.st_size;
+	if (pcap_map_size <= sizeof(struct pcap_filehdr)) {
+		rl_printf("pcap file too small!\n");
+		return CMD_ERR;
+	}
+
+	pcap_ptr_va_start = mmap(NULL, pcap_map_size, PROT_READ,
+				 MAP_SHARED | MAP_LOCKED, pcap_fd, 0);
+	if (pcap_ptr_va_start == MAP_FAILED) {
+		rl_printf("mmap of file failed!");
+		return CMD_ERR;
+	}
+
+	hdr = (void *) pcap_ptr_va_start;
+	if (hdr->magic != TCPDUMP_MAGIC) {
+		rl_printf("wrong pcap magic!\n");
+		return CMD_ERR;
+	}
+
+	pcap_reset_pkt();
+
+	return CMD_OK;
+
+}
+
+static void try_close_pcap(void)
+{
+	if (pcap_fd >= 0) {
+		munmap(pcap_ptr_va_start, pcap_map_size);
+		close(pcap_fd);
+
+		pcap_ptr_va_start = pcap_ptr_va_curr = NULL;
+		pcap_map_size = 0;
+		pcap_packet = 0;
+		pcap_fd = -1;
+	}
+}
+
+static int cmd_load_bpf(char *bpf_string)
+{
+	char sp, *token, separator = ',';
+	unsigned short bpf_len, i = 0;
+	struct sock_filter tmp;
+
+	bpf_prog_len = 0;
+	memset(bpf_image, 0, sizeof(bpf_image));
+
+	if (sscanf(bpf_string, "%hu%c", &bpf_len, &sp) != 2 ||
+	    sp != separator || bpf_len > BPF_MAXINSNS || bpf_len == 0) {
+		rl_printf("syntax error in head length encoding!\n");
+		return CMD_ERR;
+	}
+
+	token = bpf_string;
+	while ((token = strchr(token, separator)) && (++token)[0]) {
+		if (i >= bpf_len) {
+			rl_printf("program exceeds encoded length!\n");
+			return CMD_ERR;
+		}
+
+		if (sscanf(token, "%hu %hhu %hhu %u,",
+			   &tmp.code, &tmp.jt, &tmp.jf, &tmp.k) != 4) {
+			rl_printf("syntax error at instruction %d!\n", i);
+			return CMD_ERR;
+		}
+
+		bpf_image[i].code = tmp.code;
+		bpf_image[i].jt = tmp.jt;
+		bpf_image[i].jf = tmp.jf;
+		bpf_image[i].k = tmp.k;
+
+		i++;
+	}
+
+	if (i != bpf_len) {
+		rl_printf("syntax error exceeding encoded length!\n");
+		return CMD_ERR;
+	} else
+		bpf_prog_len = bpf_len;
+	if (!bpf_runnable(bpf_image, bpf_prog_len))
+		bpf_prog_len = 0;
+
+	return CMD_OK;
+}
+
+static int cmd_load_pcap(char *file)
+{
+	char *file_trim, *tmp;
+
+	file_trim = strtok_r(file, " ", &tmp);
+	if (file_trim == NULL)
+		return CMD_ERR;
+
+	try_close_pcap();
+
+	return try_load_pcap(file_trim);
+}
+
+static int cmd_load(char *arg)
+{
+	char *subcmd, *cont, *tmp = strdup(arg);
+	int ret = CMD_OK;
+
+	subcmd = strtok_r(tmp, " ", &cont);
+	if (subcmd == NULL)
+		goto out;
+	if (matches(subcmd, "bpf") == 0) {
+		bpf_reset();
+		bpf_reset_breakpoints();
+
+		ret = cmd_load_bpf(cont);
+	} else if (matches(subcmd, "pcap") == 0) {
+		ret = cmd_load_pcap(cont);
+	} else {
+out:
+		rl_printf("bpf <code>:  load bpf code\n");
+		rl_printf("pcap <file>: load pcap file\n");
+		ret = CMD_ERR;
+	}
+
+	free(tmp);
+	return ret;
+}
+
+static int cmd_step(char *num)
+{
+	struct pcap_pkthdr *hdr;
+	int steps, ret;
+
+	if (!bpf_prog_loaded() || !pcap_loaded())
+		return CMD_ERR;
+
+	steps = strtol(num, NULL, 10);
+	if (steps == 0 || strlen(num) == 0)
+		steps = 1;
+	if (steps < 0) {
+		if (!bpf_restore_regs(steps))
+			return CMD_ERR;
+		steps = 1;
+	}
+
+	hdr = pcap_curr_pkt();
+	ret = bpf_run_stepping(bpf_image, bpf_prog_len,
+			       (uint8_t *) hdr + sizeof(*hdr),
+			       hdr->caplen, hdr->len, steps);
+	if (ret >= 0 || bpf_curr.Rs) {
+		bpf_reset();
+		if (!pcap_next_pkt()) {
+			rl_printf("(going back to first packet)\n");
+			pcap_reset_pkt();
+		} else {
+			rl_printf("(next packet)\n");
+		}
+	}
+
+	return CMD_OK;
+}
+
+static int cmd_select(char *num)
+{
+	unsigned int which, i;
+	bool have_next = true;
+
+	if (!pcap_loaded() || strlen(num) == 0)
+		return CMD_ERR;
+
+	which = strtoul(num, NULL, 10);
+	if (which == 0) {
+		rl_printf("packet count starts with 1, clamping!\n");
+		which = 1;
+	}
+
+	pcap_reset_pkt();
+	bpf_reset();
+
+	for (i = 0; i < which && (have_next = pcap_next_pkt()); i++)
+		/* noop */;
+	if (!have_next || pcap_curr_pkt() == NULL) {
+		rl_printf("no packet #%u available!\n", which);
+		pcap_reset_pkt();
+		return CMD_ERR;
+	}
+
+	return CMD_OK;
+}
+
+static int cmd_breakpoint(char *subcmd)
+{
+	if (!bpf_prog_loaded())
+		return CMD_ERR;
+	if (strlen(subcmd) == 0)
+		bpf_dump_breakpoints();
+	else if (matches(subcmd, "reset") == 0)
+		bpf_reset_breakpoints();
+	else {
+		unsigned int where = strtoul(subcmd, NULL, 10);
+
+		if (where < bpf_prog_len) {
+			bpf_set_breakpoints(where);
+			rl_printf("breakpoint at: ");
+			bpf_disasm(bpf_image[where], where);
+		}
+	}
+
+	return CMD_OK;
+}
+
+static int cmd_run(char *num)
+{
+	static uint32_t pass, fail;
+	bool has_limit = true;
+	int pkts = 0, i = 0;
+
+	if (!bpf_prog_loaded() || !pcap_loaded())
+		return CMD_ERR;
+
+	pkts = strtol(num, NULL, 10);
+	if (pkts == 0 || strlen(num) == 0)
+		has_limit = false;
+
+	do {
+		struct pcap_pkthdr *hdr = pcap_curr_pkt();
+		int ret = bpf_run_all(bpf_image, bpf_prog_len,
+				      (uint8_t *) hdr + sizeof(*hdr),
+				      hdr->caplen, hdr->len);
+		if (ret > 0)
+			pass++;
+		else if (ret == 0)
+			fail++;
+		else
+			return CMD_OK;
+		bpf_reset();
+	} while (pcap_next_pkt() && (!has_limit || (has_limit && ++i < pkts)));
+
+	rl_printf("bpf passes:%u fails:%u\n", pass, fail);
+
+	pcap_reset_pkt();
+	bpf_reset();
+
+	pass = fail = 0;
+	return CMD_OK;
+}
+
+static int cmd_disassemble(char *line_string)
+{
+	bool single_line = false;
+	unsigned long line;
+
+	if (!bpf_prog_loaded())
+		return CMD_ERR;
+	if (strlen(line_string) > 0 &&
+	    (line = strtoul(line_string, NULL, 10)) < bpf_prog_len)
+		single_line = true;
+	if (single_line)
+		bpf_disasm(bpf_image[line], line);
+	else
+		bpf_disasm_all(bpf_image, bpf_prog_len);
+
+	return CMD_OK;
+}
+
+static int cmd_dump(char *dontcare)
+{
+	if (!bpf_prog_loaded())
+		return CMD_ERR;
+
+	bpf_dump_all(bpf_image, bpf_prog_len);
+
+	return CMD_OK;
+}
+
+static int cmd_quit(char *dontcare)
+{
+	return CMD_EX;
+}
+
+static const struct shell_cmd cmds[] = {
+	{ .name = "load", .func = cmd_load },
+	{ .name = "select", .func = cmd_select },
+	{ .name = "step", .func = cmd_step },
+	{ .name = "run", .func = cmd_run },
+	{ .name = "breakpoint", .func = cmd_breakpoint },
+	{ .name = "disassemble", .func = cmd_disassemble },
+	{ .name = "dump", .func = cmd_dump },
+	{ .name = "quit", .func = cmd_quit },
+};
+
+static int execf(char *arg)
+{
+	char *cmd, *cont, *tmp = strdup(arg);
+	int i, ret = 0, len;
+
+	cmd = strtok_r(tmp, " ", &cont);
+	if (cmd == NULL)
+		goto out;
+	len = strlen(cmd);
+	for (i = 0; i < array_size(cmds); i++) {
+		if (len != strlen(cmds[i].name))
+			continue;
+		if (strncmp(cmds[i].name, cmd, len) == 0) {
+			ret = cmds[i].func(cont);
+			break;
+		}
+	}
+out:
+	free(tmp);
+	return ret;
+}
+
+static char *shell_comp_gen(const char *buf, int state)
+{
+	static int list_index, len;
+
+	if (!state) {
+		list_index = 0;
+		len = strlen(buf);
+	}
+
+	for (; list_index < array_size(cmds); ) {
+		const char *name = cmds[list_index].name;
+
+		list_index++;
+		if (strncmp(name, buf, len) == 0)
+			return strdup(name);
+	}
+
+	return NULL;
+}
+
+static char **shell_completion(const char *buf, int start, int end)
+{
+	char **matches = NULL;
+
+	if (start == 0)
+		matches = rl_completion_matches(buf, shell_comp_gen);
+
+	return matches;
+}
+
+static void intr_shell(int sig)
+{
+	if (rl_end)
+		rl_kill_line(-1, 0);
+
+	rl_crlf();
+	rl_refresh_line(0, 0);
+	rl_free_line_state();
+}
+
+static void init_shell(FILE *fin, FILE *fout)
+{
+	char file[128];
+
+	snprintf(file, sizeof(file), "%s/.bpf_dbg_history", getenv("HOME"));
+	read_history(file);
+
+	rl_instream = fin;
+	rl_outstream = fout;
+
+	rl_readline_name = "bpf_dbg";
+	rl_terminal_name = getenv("TERM");
+
+	rl_catch_signals = 0;
+	rl_catch_sigwinch = 1;
+
+	rl_attempted_completion_function = shell_completion;
+
+	rl_bind_key('\t', rl_complete);
+
+	rl_bind_key_in_map('\t', rl_complete, emacs_meta_keymap);
+	rl_bind_key_in_map('\033', rl_complete, emacs_meta_keymap);
+
+	snprintf(file, sizeof(file), "%s/.bpf_dbg_init", getenv("HOME"));
+	rl_read_init_file(file);
+
+	rl_prep_terminal(0);
+	rl_set_signals();
+
+	signal(SIGINT, intr_shell);
+}
+
+static void exit_shell(FILE *fin, FILE *fout)
+{
+	char file[128];
+
+	snprintf(file, sizeof(file), "%s/.bpf_dbg_history", getenv("HOME"));
+	write_history(file);
+
+	clear_history();
+	rl_deprep_terminal();
+
+	try_close_pcap();
+
+	if (fin != stdin)
+		fclose(fin);
+	if (fout != stdout)
+		fclose(fout);
+}
+
+static int run_shell_loop(FILE *fin, FILE *fout)
+{
+	char *buf;
+
+	init_shell(fin, fout);
+
+	while ((buf = readline("> ")) != NULL) {
+		int ret = execf(buf);
+		if (ret == CMD_EX)
+			break;
+		if (ret == CMD_OK && strlen(buf) > 0)
+			add_history(buf);
+
+		free(buf);
+	}
+
+	exit_shell(fin, fout);
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	FILE *fin = NULL, *fout = NULL;
+
+	if (argc >= 2)
+		fin = fopen(argv[1], "r");
+	if (argc >= 3)
+		fout = fopen(argv[2], "w");
+
+	return run_shell_loop(fin ? : stdin, fout ? : stdout);
+}
diff --git a/tools/bpf/bpf_exp.l b/tools/bpf/bpf_exp.l
new file mode 100644
index 000000000000..bd83149e7be0
--- /dev/null
+++ b/tools/bpf/bpf_exp.l
@@ -0,0 +1,198 @@
+/*
+ * BPF asm code lexer
+ *
+ * This program is free software; you can distribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * Syntax kept close to:
+ *
+ * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
+ * architecture for user-level packet capture. In Proceedings of the
+ * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
+ * Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
+ * CA, USA, 2-2.
+ *
+ * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+%{
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <linux/filter.h>
+
+#include "bpf_exp.yacc.h"
+
+extern void yyerror(const char *str);
+
+%}
+
+%option align
+%option ecs
+
+%option nounput
+%option noreject
+%option noinput
+%option noyywrap
+
+%option 8bit
+%option caseless
+%option yylineno
+
+%%
+
+"ldb"		{ return OP_LDB; }
+"ldh"		{ return OP_LDH; }
+"ld"		{ return OP_LD; }
+"ldi"		{ return OP_LDI; }
+"ldx"		{ return OP_LDX; }
+"ldxi"		{ return OP_LDXI; }
+"ldxb"		{ return OP_LDXB; }
+"st"		{ return OP_ST; }
+"stx"		{ return OP_STX; }
+"jmp"		{ return OP_JMP; }
+"ja"		{ return OP_JMP; }
+"jeq"		{ return OP_JEQ; }
+"jneq"		{ return OP_JNEQ; }
+"jne"		{ return OP_JNEQ; }
+"jlt"		{ return OP_JLT; }
+"jle"		{ return OP_JLE; }
+"jgt"		{ return OP_JGT; }
+"jge"		{ return OP_JGE; }
+"jset"		{ return OP_JSET; }
+"add"		{ return OP_ADD; }
+"sub"		{ return OP_SUB; }
+"mul"		{ return OP_MUL; }
+"div"		{ return OP_DIV; }
+"mod"		{ return OP_MOD; }
+"neg"		{ return OP_NEG; }
+"and"		{ return OP_AND; }
+"xor"		{ return OP_XOR; }
+"or"		{ return OP_OR; }
+"lsh"		{ return OP_LSH; }
+"rsh"		{ return OP_RSH; }
+"ret"		{ return OP_RET; }
+"tax"		{ return OP_TAX; }
+"txa"		{ return OP_TXA; }
+
+"#"?("len")	{ return K_PKT_LEN; }
+
+"#"?("proto")	{
+		yylval.number = SKF_AD_PROTOCOL;
+		return extension;
+	}
+"#"?("type")	{
+		yylval.number = SKF_AD_PKTTYPE;
+		return extension;
+	}
+"#"?("poff")	{
+		yylval.number = SKF_AD_PAY_OFFSET;
+		return extension;
+	}
+"#"?("ifidx")	{
+		yylval.number = SKF_AD_IFINDEX;
+		return extension;
+	}
+"#"?("nla")	{
+		yylval.number = SKF_AD_NLATTR;
+		return extension;
+	}
+"#"?("nlan")	{
+		yylval.number = SKF_AD_NLATTR_NEST;
+		return extension;
+	}
+"#"?("mark")	{
+		yylval.number = SKF_AD_MARK;
+		return extension;
+	}
+"#"?("queue")	{
+		yylval.number = SKF_AD_QUEUE;
+		return extension;
+	}
+"#"?("hatype")	{
+		yylval.number = SKF_AD_HATYPE;
+		return extension;
+	}
+"#"?("rxhash")	{
+		yylval.number = SKF_AD_RXHASH;
+		return extension;
+	}
+"#"?("cpu")	{
+		yylval.number = SKF_AD_CPU;
+		return extension;
+	}
+"#"?("vlan_tci") {
+		yylval.number = SKF_AD_VLAN_TAG;
+		return extension;
+	}
+"#"?("vlan_pr")	{
+		yylval.number = SKF_AD_VLAN_TAG_PRESENT;
+		return extension;
+	}
+"#"?("vlan_avail") {
+		yylval.number = SKF_AD_VLAN_TAG_PRESENT;
+		return extension;
+	}
+"#"?("vlan_tpid") {
+		yylval.number = SKF_AD_VLAN_TPID;
+		return extension;
+	}
+"#"?("rand")	{
+		yylval.number = SKF_AD_RANDOM;
+		return extension;
+	}
+
+":"		{ return ':'; }
+","		{ return ','; }
+"#"		{ return '#'; }
+"%"		{ return '%'; }
+"["		{ return '['; }
+"]"		{ return ']'; }
+"("		{ return '('; }
+")"		{ return ')'; }
+"x"		{ return 'x'; }
+"a"		{ return 'a'; }
+"+"		{ return '+'; }
+"M"		{ return 'M'; }
+"*"		{ return '*'; }
+"&"		{ return '&'; }
+
+([0][x][a-fA-F0-9]+) {
+			yylval.number = strtoul(yytext, NULL, 16);
+			return number;
+		}
+([0][b][0-1]+)	{
+			yylval.number = strtol(yytext + 2, NULL, 2);
+			return number;
+		}
+(([0])|([-+]?[1-9][0-9]*)) {
+			yylval.number = strtol(yytext, NULL, 10);
+			return number;
+		}
+([0][0-9]+)	{
+			yylval.number = strtol(yytext + 1, NULL, 8);
+			return number;
+		}
+[a-zA-Z_][a-zA-Z0-9_]+ {
+			yylval.label = strdup(yytext);
+			return label;
+		}
+
+"/*"([^\*]|\*[^/])*"*/"		{ /* NOP */ }
+";"[^\n]*			{ /* NOP */ }
+^#.*				{ /* NOP */ }
+[ \t]+				{ /* NOP */ }
+[ \n]+				{ /* NOP */ }
+
+.		{
+			printf("unknown character \'%s\'", yytext);
+			yyerror("lex unknown character");
+		}
+
+%%
diff --git a/tools/bpf/bpf_exp.y b/tools/bpf/bpf_exp.y
new file mode 100644
index 000000000000..56ba1de50784
--- /dev/null
+++ b/tools/bpf/bpf_exp.y
@@ -0,0 +1,656 @@
+/*
+ * BPF asm code parser
+ *
+ * This program is free software; you can distribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * Syntax kept close to:
+ *
+ * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
+ * architecture for user-level packet capture. In Proceedings of the
+ * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
+ * Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
+ * CA, USA, 2-2.
+ *
+ * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+%{
+
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+#include <linux/filter.h>
+
+#include "bpf_exp.yacc.h"
+
+enum jmp_type { JTL, JFL, JKL };
+
+extern FILE *yyin;
+extern int yylineno;
+extern int yylex(void);
+extern void yyerror(const char *str);
+
+extern void bpf_asm_compile(FILE *fp, bool cstyle);
+static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k);
+static void bpf_set_curr_label(char *label);
+static void bpf_set_jmp_label(char *label, enum jmp_type type);
+
+%}
+
+%union {
+	char *label;
+	uint32_t number;
+}
+
+%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
+%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
+%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
+%token OP_LDXI
+
+%token K_PKT_LEN
+
+%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'
+
+%token extension number label
+
+%type <label> label
+%type <number> extension
+%type <number> number
+
+%%
+
+prog
+	: line
+	| prog line
+	;
+
+line
+	: instr
+	| labelled_instr
+	;
+
+labelled_instr
+	: labelled instr
+	;
+
+instr
+	: ldb
+	| ldh
+	| ld
+	| ldi
+	| ldx
+	| ldxi
+	| st
+	| stx
+	| jmp
+	| jeq
+	| jneq
+	| jlt
+	| jle
+	| jgt
+	| jge
+	| jset
+	| add
+	| sub
+	| mul
+	| div
+	| mod
+	| neg
+	| and
+	| or
+	| xor
+	| lsh
+	| rsh
+	| ret
+	| tax
+	| txa
+	;
+
+labelled
+	: label ':' { bpf_set_curr_label($1); }
+	;
+
+ldb
+	: OP_LDB '[' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
+	| OP_LDB '[' '%' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $6); }
+	| OP_LDB '[' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
+	| OP_LDB extension {
+		bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
+				   SKF_AD_OFF + $2); }
+	;
+
+ldh
+	: OP_LDH '[' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
+	| OP_LDH '[' '%' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $6); }
+	| OP_LDH '[' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
+	| OP_LDH extension {
+		bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
+				   SKF_AD_OFF + $2); }
+	;
+
+ldi
+	: OP_LDI '#' number {
+		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
+	| OP_LDI number {
+		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); }
+	;
+
+ld
+	: OP_LD '#' number {
+		bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
+	| OP_LD K_PKT_LEN {
+		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); }
+	| OP_LD extension {
+		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
+				   SKF_AD_OFF + $2); }
+	| OP_LD 'M' '[' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
+	| OP_LD '[' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
+	| OP_LD '[' '%' 'x' '+' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $6); }
+	| OP_LD '[' number ']' {
+		bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
+	;
+
+ldxi
+	: OP_LDXI '#' number {
+		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
+	| OP_LDXI number {
+		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); }
+	;
+
+ldx
+	: OP_LDX '#' number {
+		bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
+	| OP_LDX K_PKT_LEN {
+		bpf_set_curr_instr(BPF_LDX | BPF_W | BPF_LEN, 0, 0, 0); }
+	| OP_LDX 'M' '[' number ']' {
+		bpf_set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
+	| OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
+		if ($2 != 4 || $9 != 0xf) {
+			fprintf(stderr, "ldxb offset not supported!\n");
+			exit(0);
+		} else {
+			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
+	| OP_LDX number '*' '(' '[' number ']' '&' number ')' {
+		if ($2 != 4 || $9 != 0xf) {
+			fprintf(stderr, "ldxb offset not supported!\n");
+			exit(0);
+		} else {
+			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
+	;
+
+st
+	: OP_ST 'M' '[' number ']' {
+		bpf_set_curr_instr(BPF_ST, 0, 0, $4); }
+	;
+
+stx
+	: OP_STX 'M' '[' number ']' {
+		bpf_set_curr_instr(BPF_STX, 0, 0, $4); }
+	;
+
+jmp
+	: OP_JMP label {
+		bpf_set_jmp_label($2, JKL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
+	;
+
+jeq
+	: OP_JEQ '#' number ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
+	| OP_JEQ 'x' ',' label ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_jmp_label($6, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JEQ '%' 'x' ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JEQ '#' number ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
+	| OP_JEQ 'x' ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JEQ '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	;
+
+jneq
+	: OP_JNEQ '#' number ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
+	| OP_JNEQ 'x' ',' label {
+		bpf_set_jmp_label($4, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JNEQ '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	;
+
+jlt
+	: OP_JLT '#' number ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
+	| OP_JLT 'x' ',' label {
+		bpf_set_jmp_label($4, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JLT '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	;
+
+jle
+	: OP_JLE '#' number ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
+	| OP_JLE 'x' ',' label {
+		bpf_set_jmp_label($4, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JLE '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	;
+
+jgt
+	: OP_JGT '#' number ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
+	| OP_JGT 'x' ',' label ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_jmp_label($6, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JGT '%' 'x' ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JGT '#' number ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
+	| OP_JGT 'x' ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JGT '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	;
+
+jge
+	: OP_JGE '#' number ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
+	| OP_JGE 'x' ',' label ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_jmp_label($6, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JGE '%' 'x' ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JGE '#' number ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
+	| OP_JGE 'x' ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JGE '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	;
+
+jset
+	: OP_JSET '#' number ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
+	| OP_JSET 'x' ',' label ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_jmp_label($6, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	| OP_JSET '%' 'x' ',' label ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_jmp_label($7, JFL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	| OP_JSET '#' number ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
+	| OP_JSET 'x' ',' label {
+		bpf_set_jmp_label($4, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	| OP_JSET '%' 'x' ',' label {
+		bpf_set_jmp_label($5, JTL);
+		bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	;
+
+add
+	: OP_ADD '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
+	| OP_ADD 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
+	| OP_ADD '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
+	;
+
+sub
+	: OP_SUB '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
+	| OP_SUB 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
+	| OP_SUB '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
+	;
+
+mul
+	: OP_MUL '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
+	| OP_MUL 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
+	| OP_MUL '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
+	;
+
+div
+	: OP_DIV '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
+	| OP_DIV 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
+	| OP_DIV '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
+	;
+
+mod
+	: OP_MOD '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
+	| OP_MOD 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
+	| OP_MOD '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
+	;
+
+neg
+	: OP_NEG {
+		bpf_set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
+	;
+
+and
+	: OP_AND '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
+	| OP_AND 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
+	| OP_AND '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
+	;
+
+or
+	: OP_OR '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
+	| OP_OR 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
+	| OP_OR '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
+	;
+
+xor
+	: OP_XOR '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
+	| OP_XOR 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
+	| OP_XOR '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
+	;
+
+lsh
+	: OP_LSH '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
+	| OP_LSH 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
+	| OP_LSH '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
+	;
+
+rsh
+	: OP_RSH '#' number {
+		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
+	| OP_RSH 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
+	| OP_RSH '%' 'x' {
+		bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
+	;
+
+ret
+	: OP_RET 'a' {
+		bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
+	| OP_RET '%' 'a' {
+		bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
+	| OP_RET 'x' {
+		bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
+	| OP_RET '%' 'x' {
+		bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
+	| OP_RET '#' number {
+		bpf_set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
+	;
+
+tax
+	: OP_TAX {
+		bpf_set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
+	;
+
+txa
+	: OP_TXA {
+		bpf_set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
+	;
+
+%%
+
+static int curr_instr = 0;
+static struct sock_filter out[BPF_MAXINSNS];
+static char **labels, **labels_jt, **labels_jf, **labels_k;
+
+static void bpf_assert_max(void)
+{
+	if (curr_instr >= BPF_MAXINSNS) {
+		fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS);
+		exit(0);
+	}
+}
+
+static void bpf_set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf,
+			       uint32_t k)
+{
+	bpf_assert_max();
+	out[curr_instr].code = code;
+	out[curr_instr].jt = jt;
+	out[curr_instr].jf = jf;
+	out[curr_instr].k = k;
+	curr_instr++;
+}
+
+static void bpf_set_curr_label(char *label)
+{
+	bpf_assert_max();
+	labels[curr_instr] = label;
+}
+
+static void bpf_set_jmp_label(char *label, enum jmp_type type)
+{
+	bpf_assert_max();
+	switch (type) {
+	case JTL:
+		labels_jt[curr_instr] = label;
+		break;
+	case JFL:
+		labels_jf[curr_instr] = label;
+		break;
+	case JKL:
+		labels_k[curr_instr] = label;
+		break;
+	}
+}
+
+static int bpf_find_insns_offset(const char *label)
+{
+	int i, max = curr_instr, ret = -ENOENT;
+
+	for (i = 0; i < max; i++) {
+		if (labels[i] && !strcmp(label, labels[i])) {
+			ret = i;
+			break;
+		}
+	}
+
+	if (ret == -ENOENT) {
+		fprintf(stderr, "no such label \'%s\'!\n", label);
+		exit(0);
+	}
+
+	return ret;
+}
+
+static void bpf_stage_1_insert_insns(void)
+{
+	yyparse();
+}
+
+static void bpf_reduce_k_jumps(void)
+{
+	int i;
+
+	for (i = 0; i < curr_instr; i++) {
+		if (labels_k[i]) {
+			int off = bpf_find_insns_offset(labels_k[i]);
+			out[i].k = (uint32_t) (off - i - 1);
+		}
+	}
+}
+
+static void bpf_reduce_jt_jumps(void)
+{
+	int i;
+
+	for (i = 0; i < curr_instr; i++) {
+		if (labels_jt[i]) {
+			int off = bpf_find_insns_offset(labels_jt[i]);
+			out[i].jt = (uint8_t) (off - i -1);
+		}
+	}
+}
+
+static void bpf_reduce_jf_jumps(void)
+{
+	int i;
+
+	for (i = 0; i < curr_instr; i++) {
+		if (labels_jf[i]) {
+			int off = bpf_find_insns_offset(labels_jf[i]);
+			out[i].jf = (uint8_t) (off - i - 1);
+		}
+	}
+}
+
+static void bpf_stage_2_reduce_labels(void)
+{
+	bpf_reduce_k_jumps();
+	bpf_reduce_jt_jumps();
+	bpf_reduce_jf_jumps();
+}
+
+static void bpf_pretty_print_c(void)
+{
+	int i;
+
+	for (i = 0; i < curr_instr; i++)
+		printf("{ %#04x, %2u, %2u, %#010x },\n", out[i].code,
+		       out[i].jt, out[i].jf, out[i].k);
+}
+
+static void bpf_pretty_print(void)
+{
+	int i;
+
+	printf("%u,", curr_instr);
+	for (i = 0; i < curr_instr; i++)
+		printf("%u %u %u %u,", out[i].code,
+		       out[i].jt, out[i].jf, out[i].k);
+	printf("\n");
+}
+
+static void bpf_init(void)
+{
+	memset(out, 0, sizeof(out));
+
+	labels = calloc(BPF_MAXINSNS, sizeof(*labels));
+	assert(labels);
+	labels_jt = calloc(BPF_MAXINSNS, sizeof(*labels_jt));
+	assert(labels_jt);
+	labels_jf = calloc(BPF_MAXINSNS, sizeof(*labels_jf));
+	assert(labels_jf);
+	labels_k = calloc(BPF_MAXINSNS, sizeof(*labels_k));
+	assert(labels_k);
+}
+
+static void bpf_destroy_labels(void)
+{
+	int i;
+
+	for (i = 0; i < curr_instr; i++) {
+		free(labels_jf[i]);
+		free(labels_jt[i]);
+		free(labels_k[i]);
+		free(labels[i]);
+	}
+}
+
+static void bpf_destroy(void)
+{
+	bpf_destroy_labels();
+	free(labels_jt);
+	free(labels_jf);
+	free(labels_k);
+	free(labels);
+}
+
+void bpf_asm_compile(FILE *fp, bool cstyle)
+{
+	yyin = fp;
+
+	bpf_init();
+	bpf_stage_1_insert_insns();
+	bpf_stage_2_reduce_labels();
+	bpf_destroy();
+
+	if (cstyle)
+		bpf_pretty_print_c();
+	else
+		bpf_pretty_print();
+
+	if (fp != stdin)
+		fclose(yyin);
+}
+
+void yyerror(const char *str)
+{
+	fprintf(stderr, "error: %s at line %d\n", str, yylineno);
+	exit(1);
+}
diff --git a/tools/bpf/bpf_jit_disasm.c b/tools/bpf/bpf_jit_disasm.c
new file mode 100644
index 000000000000..422d9abd666a
--- /dev/null
+++ b/tools/bpf/bpf_jit_disasm.c
@@ -0,0 +1,320 @@
+/*
+ * Minimal BPF JIT image disassembler
+ *
+ * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for
+ * debugging or verification purposes.
+ *
+ * To get the disassembly of the JIT code, do the following:
+ *
+ *  1) `echo 2 > /proc/sys/net/core/bpf_jit_enable`
+ *  2) Load a BPF filter (e.g. `tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24`)
+ *  3) Run e.g. `bpf_jit_disasm -o` to read out the last JIT code
+ *
+ * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+#include <bfd.h>
+#include <dis-asm.h>
+#include <regex.h>
+#include <fcntl.h>
+#include <sys/klog.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#define CMD_ACTION_SIZE_BUFFER		10
+#define CMD_ACTION_READ_ALL		3
+
+static void get_exec_path(char *tpath, size_t size)
+{
+	char *path;
+	ssize_t len;
+
+	snprintf(tpath, size, "/proc/%d/exe", (int) getpid());
+	tpath[size - 1] = 0;
+
+	path = strdup(tpath);
+	assert(path);
+
+	len = readlink(path, tpath, size);
+	tpath[len] = 0;
+
+	free(path);
+}
+
+static void get_asm_insns(uint8_t *image, size_t len, int opcodes)
+{
+	int count, i, pc = 0;
+	char tpath[256];
+	struct disassemble_info info;
+	disassembler_ftype disassemble;
+	bfd *bfdf;
+
+	memset(tpath, 0, sizeof(tpath));
+	get_exec_path(tpath, sizeof(tpath));
+
+	bfdf = bfd_openr(tpath, NULL);
+	assert(bfdf);
+	assert(bfd_check_format(bfdf, bfd_object));
+
+	init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf);
+	info.arch = bfd_get_arch(bfdf);
+	info.mach = bfd_get_mach(bfdf);
+	info.buffer = image;
+	info.buffer_length = len;
+
+	disassemble_init_for_target(&info);
+
+	disassemble = disassembler(bfdf);
+	assert(disassemble);
+
+	do {
+		printf("%4x:\t", pc);
+
+		count = disassemble(pc, &info);
+
+		if (opcodes) {
+			printf("\n\t");
+			for (i = 0; i < count; ++i)
+				printf("%02x ", (uint8_t) image[pc + i]);
+		}
+		printf("\n");
+
+		pc += count;
+	} while(count > 0 && pc < len);
+
+	bfd_close(bfdf);
+}
+
+static char *get_klog_buff(unsigned int *klen)
+{
+	int ret, len;
+	char *buff;
+
+	len = klogctl(CMD_ACTION_SIZE_BUFFER, NULL, 0);
+	if (len < 0)
+		return NULL;
+
+	buff = malloc(len);
+	if (!buff)
+		return NULL;
+
+	ret = klogctl(CMD_ACTION_READ_ALL, buff, len);
+	if (ret < 0) {
+		free(buff);
+		return NULL;
+	}
+
+	*klen = ret;
+	return buff;
+}
+
+static char *get_flog_buff(const char *file, unsigned int *klen)
+{
+	int fd, ret, len;
+	struct stat fi;
+	char *buff;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	ret = fstat(fd, &fi);
+	if (ret < 0 || !S_ISREG(fi.st_mode))
+		goto out;
+
+	len = fi.st_size + 1;
+	buff = malloc(len);
+	if (!buff)
+		goto out;
+
+	memset(buff, 0, len);
+	ret = read(fd, buff, len - 1);
+	if (ret <= 0)
+		goto out_free;
+
+	close(fd);
+	*klen = ret;
+	return buff;
+out_free:
+	free(buff);
+out:
+	close(fd);
+	return NULL;
+}
+
+static char *get_log_buff(const char *file, unsigned int *klen)
+{
+	return file ? get_flog_buff(file, klen) : get_klog_buff(klen);
+}
+
+static void put_log_buff(char *buff)
+{
+	free(buff);
+}
+
+static uint8_t *get_last_jit_image(char *haystack, size_t hlen,
+				   unsigned int *ilen)
+{
+	char *ptr, *pptr, *tmp;
+	off_t off = 0;
+	int ret, flen, proglen, pass, ulen = 0;
+	regmatch_t pmatch[1];
+	unsigned long base;
+	regex_t regex;
+	uint8_t *image;
+
+	if (hlen == 0)
+		return NULL;
+
+	ret = regcomp(&regex, "flen=[[:alnum:]]+ proglen=[[:digit:]]+ "
+		      "pass=[[:digit:]]+ image=[[:xdigit:]]+", REG_EXTENDED);
+	assert(ret == 0);
+
+	ptr = haystack;
+	memset(pmatch, 0, sizeof(pmatch));
+
+	while (1) {
+		ret = regexec(&regex, ptr, 1, pmatch, 0);
+		if (ret == 0) {
+			ptr += pmatch[0].rm_eo;
+			off += pmatch[0].rm_eo;
+			assert(off < hlen);
+		} else
+			break;
+	}
+
+	ptr = haystack + off - (pmatch[0].rm_eo - pmatch[0].rm_so);
+	ret = sscanf(ptr, "flen=%d proglen=%d pass=%d image=%lx",
+		     &flen, &proglen, &pass, &base);
+	if (ret != 4) {
+		regfree(&regex);
+		return NULL;
+	}
+	if (proglen > 1000000) {
+		printf("proglen of %d too big, stopping\n", proglen);
+		return NULL;
+	}
+
+	image = malloc(proglen);
+	if (!image) {
+		printf("Out of memory\n");
+		return NULL;
+	}
+	memset(image, 0, proglen);
+
+	tmp = ptr = haystack + off;
+	while ((ptr = strtok(tmp, "\n")) != NULL && ulen < proglen) {
+		tmp = NULL;
+		if (!strstr(ptr, "JIT code"))
+			continue;
+		pptr = ptr;
+		while ((ptr = strstr(pptr, ":")))
+			pptr = ptr + 1;
+		ptr = pptr;
+		do {
+			image[ulen++] = (uint8_t) strtoul(pptr, &pptr, 16);
+			if (ptr == pptr) {
+				ulen--;
+				break;
+			}
+			if (ulen >= proglen)
+				break;
+			ptr = pptr;
+		} while (1);
+	}
+
+	assert(ulen == proglen);
+	printf("%d bytes emitted from JIT compiler (pass:%d, flen:%d)\n",
+	       proglen, pass, flen);
+	printf("%lx + <x>:\n", base);
+
+	regfree(&regex);
+	*ilen = ulen;
+	return image;
+}
+
+static void usage(void)
+{
+	printf("Usage: bpf_jit_disasm [...]\n");
+	printf("       -o          Also display related opcodes (default: off).\n");
+	printf("       -O <file>   Write binary image of code to file, don't disassemble to stdout.\n");
+	printf("       -f <file>   Read last image dump from file or stdin (default: klog).\n");
+	printf("       -h          Display this help.\n");
+}
+
+int main(int argc, char **argv)
+{
+	unsigned int len, klen, opt, opcodes = 0;
+	char *kbuff, *file = NULL;
+	char *ofile = NULL;
+	int ofd;
+	ssize_t nr;
+	uint8_t *pos;
+	uint8_t *image = NULL;
+
+	while ((opt = getopt(argc, argv, "of:O:")) != -1) {
+		switch (opt) {
+		case 'o':
+			opcodes = 1;
+			break;
+		case 'O':
+			ofile = optarg;
+			break;
+		case 'f':
+			file = optarg;
+			break;
+		default:
+			usage();
+			return -1;
+		}
+	}
+
+	bfd_init();
+
+	kbuff = get_log_buff(file, &klen);
+	if (!kbuff) {
+		fprintf(stderr, "Could not retrieve log buffer!\n");
+		return -1;
+	}
+
+	image = get_last_jit_image(kbuff, klen, &len);
+	if (!image) {
+		fprintf(stderr, "No JIT image found!\n");
+		goto done;
+	}
+	if (!ofile) {
+		get_asm_insns(image, len, opcodes);
+		goto done;
+	}
+
+	ofd = open(ofile, O_WRONLY | O_CREAT | O_TRUNC, DEFFILEMODE);
+	if (ofd < 0) {
+		fprintf(stderr, "Could not open file %s for writing: ", ofile);
+		perror(NULL);
+		goto done;
+	}
+	pos = image;
+	do {
+		nr = write(ofd, pos, len);
+		if (nr < 0) {
+			fprintf(stderr, "Could not write data to %s: ", ofile);
+			perror(NULL);
+			goto done;
+		}
+		len -= nr;
+		pos += nr;
+	} while (len);
+	close(ofd);
+
+done:
+	put_log_buff(kbuff);
+	free(image);
+	return 0;
+}