Merge tag 'upstream/1.6.1'

Upstream version 1.6.1

extensions/libxt_DSCP.t

-:PREROUTING,INPUT,FORWARD,OUTPUT,POSTROUTING
-*mangle
--j DSCP --set-dscp 0;=;OK
--j DSCP --set-dscp 0x3f;=;OK
--j DSCP --set-dscp -1;;FAIL
--j DSCP --set-dscp 0x40;;FAIL
--j DSCP --set-dscp 0x3f --set-dscp-class CS0;;FAIL
--j DSCP --set-dscp-class CS0;-j DSCP --set-dscp 0x00;OK
--j DSCP --set-dscp-class BE;-j DSCP --set-dscp 0x00;OK
--j DSCP --set-dscp-class EF;-j DSCP --set-dscp 0x2e;OK
--j DSCP;;FAIL

extensions/libxt_HMARK.t

-:INPUT,FORWARD,OUTPUT
--j HMARK;;FAIL
--j HMARK --hmark-src-prefix 32 --hmark-rnd 0x00000004 --hmark-mod 42;=;OK
--j HMARK --hmark-src-prefix 32 --hmark-dst-prefix 32 --hmark-sport-mask 0xffff --hmark-dport-mask 0xffff --hmark-proto-mask 0xffff --hmark-rnd 0x00000004 --hmark-mod 42 --hmark-offset 1 --hmark-tuple ct;=;OK
--j HMARK --hmark-src-prefix 32 --hmark-dst-prefix 32 --hmark-spi-mask 0x00000004 --hmark-proto-mask 0xffff --hmark-rnd 0x00000004 --hmark-mod 42 --hmark-offset 1 --hmark-tuple ct;=;OK
--j HMARK --hmark-src-prefix 1 --hmark-dst-prefix 2 --hmark-sport-mask 0x0003 --hmark-dport-mask 0x0004 --hmark-proto-mask 0x05 --hmark-rnd 0x00000004 --hmark-mod 42 --hmark-offset 1 --hmark-tuple ct;=;OK
-# cannot mix in spi mask:
--j HMARK --hmark-src-prefix 32 --hmark-dst-prefix 32 --hmark-sport-mask 0xffff --hmark-dport-mask 0xffff --hmark-proto-mask 0xffff --hmark-rnd 0x00000004 --hmark-mod 42 --hmark-offset 1 --hmark-tuple ct --hmark-spi-mask 4;;FAIL

extensions/libxt_IDLETIMER.t

-:INPUT,FORWARD,OUTPUT
--j IDLETIMER --timeout;;FAIL
--j IDLETIMER --timeout 42;;FAIL
--j IDLETIMER --timeout 42 --label foo;=;OK

extensions/libxt_LED.t

-:INPUT,FORWARD,OUTPUT
--j LED;;FAIL
--j LED --led-trigger-id "foo";=;OK
--j LED --led-trigger-id "foo" --led-delay 42 --led-always-blink;=;OK

extensions/libxt_MARK.t

-:INPUT,FORWARD,OUTPUT
--j MARK --set-xmark 0xfeedcafe/0xfeedcafe;=;OK
--j MARK --set-xmark 0;=;OK
--j MARK --set-xmark 4294967295;-j MARK --set-xmark 0xffffffff;OK
--j MARK --set-xmark 4294967296;;FAIL
--j MARK --set-xmark -1;;FAIL
--j MARK;;FAIL

extensions/libxt_NFLOG.t

-:INPUT,FORWARD,OUTPUT
--j NFLOG --nflog-group 1;=;OK
--j NFLOG --nflog-group 65535;=;OK
--j NFLOG --nflog-group 65536;;FAIL
--j NFLOG --nflog-group 0;-j NFLOG;OK
--j NFLOG --nflog-range 1;=;OK
--j NFLOG --nflog-range 4294967295;=;OK
--j NFLOG --nflog-range 4294967296;;FAIL
--j NFLOG --nflog-range -1;;FAIL
--j NFLOG --nflog-size 0;=;OK
--j NFLOG --nflog-size 1;=;OK
--j NFLOG --nflog-size 4294967295;=;OK
--j NFLOG --nflog-size 4294967296;;FAIL
--j NFLOG --nflog-size -1;;FAIL
-# ERROR: cannot find: iptables -I INPUT -j NFLOG --nflog-prefix  xxxxxx [...]
-# -j NFLOG --nflog-prefix xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx;=;OK
-# ERROR: should fail: iptables -A INPUT -j NFLOG --nflog-prefix  xxxxxxx [...]
-#  -j NFLOG --nflog-prefix xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx;;FAIL
--j NFLOG --nflog-threshold 1;=;OK
-# ERROR: line 13 (should fail: iptables -A INPUT -j NFLOG --nflog-threshold 0
-# -j NFLOG --nflog-threshold 0;;FAIL
--j NFLOG --nflog-threshold 65535;=;OK
--j NFLOG --nflog-threshold 65536;;FAIL
--j NFLOG;=;OK

extensions/libxt_NFQUEUE.t

-:INPUT,FORWARD,OUTPUT
--j NFQUEUE;=;OK
--j NFQUEUE --queue-num 0;=;OK
--j NFQUEUE --queue-num 65535;=;OK
--j NFQUEUE --queue-num 65536;;FAIL
--j NFQUEUE --queue-num -1;;FAIL
-# it says "NFQUEUE: number of total queues is 0", overflow in NFQUEUE_parse_v1?
-# ERROR: cannot load: iptables -A INPUT -j NFQUEUE --queue-balance 0:65535
-# -j NFQUEUE --queue-balance 0:65535;=;OK
--j NFQUEUE --queue-balance 0:65536;;FAIL
--j NFQUEUE --queue-balance -1:65535;;FAIL
--j NFQUEUE --queue-num 10 --queue-bypass;=;OK
--j NFQUEUE --queue-balance 0:6 --queue-cpu-fanout --queue-bypass;-j NFQUEUE --queue-balance 0:6 --queue-bypass --queue-cpu-fanout;OK
--j NFQUEUE --queue-bypass --queue-balance 0:6 --queue-cpu-fanout;-j NFQUEUE --queue-balance 0:6 --queue-bypass --queue-cpu-fanout;OK
--j NFQUEUE --queue-balance 0:6 --queue-bypass;=;OK
--j NFQUEUE --queue-bypass;-j NFQUEUE --queue-num 0 --queue-bypass;OK

extensions/libxt_NOTRACK.t

-:PREROUTING,OUTPUT
-*raw
-# ERROR: cannot find: iptables -I PREROUTING -t raw -j NOTRACK
-#-j NOTRACK;=;OK

extensions/libxt_RATEEST.t

-:INPUT,FORWARD,OUTPUT
--j RATEEST --rateest-name RE1 --rateest-interval 250.0ms --rateest-ewmalog 500.0ms;=;OK

extensions/libxt_SET.t

-:INPUT,FORWARD,OUTPUT
-# fails: foo does not exist
--j SET --add-set foo src,dst;;FAIL

extensions/libxt_SYNPROXY.t

-:INPUT,FORWARD
--j SYNPROXY --sack-perm --timestamp --mss 1460 --wscale 9;;FAIL
--p tcp -m tcp --dport 42 -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 9 --mss 1460;=;OK

extensions/libxt_TCPMSS.t

-:FORWARD,OUTPUT,POSTROUTING
-*mangle
--j TCPMSS;;FAIL
--p tcp -j TCPMSS --set-mss 42;;FAIL
--p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j TCPMSS --set-mss 42;=;OK
--p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j TCPMSS --clamp-mss-to-pmtu;=;OK

extensions/libxt_TCPOPTSTRIP.t

-:PREROUTING,INPUT,FORWARD,OUTPUT,POSTROUTING
-*mangle
--j TCPOPTSTRIP;;FAIL
--p tcp -j TCPOPTSTRIP;=;OK
--p tcp -j TCPOPTSTRIP --strip-options 2,3,4,5,6,7;=;OK
--p tcp -j TCPOPTSTRIP --strip-options 0;;FAIL
--p tcp -j TCPOPTSTRIP --strip-options 1;;FAIL
--p tcp -j TCPOPTSTRIP --strip-options 1,2;;FAIL

extensions/libxt_TEE.t

-:INPUT,FORWARD,OUTPUT
--j TEE --gateway 1.1.1.1;=;OK
--j TEE ! --gateway 1.1.1.1;;FAIL
--j TEE;;FAIL

extensions/libxt_TOS.t

-:PREROUTING,INPUT,FORWARD,OUTPUT,POSTROUTING
-*mangle
--j TOS --set-tos 0x1f;=;OK
--j TOS --set-tos 0x1f/0x1f;=;OK
-# maximum TOS is 0x1f (5 bits)
-# ERROR: should fail: iptables -A PREROUTING -t mangle -j TOS --set-tos 0xff
-# -j TOS --set-tos 0xff;;FAIL
--j TOS --set-tos Minimize-Delay;-j TOS --set-tos 0x10;OK
--j TOS --set-tos Maximize-Throughput;-j TOS --set-tos 0x08;OK
--j TOS --set-tos Maximize-Reliability;-j TOS --set-tos 0x04;OK
--j TOS --set-tos Minimize-Cost;-j TOS --set-tos 0x02;OK
--j TOS --set-tos Normal-Service;-j TOS --set-tos 0x00;OK
--j TOS --and-tos 0x12;-j TOS --set-tos 0x00/0xed;OK
--j TOS --or-tos 0x12;-j TOS --set-tos 0x12/0x12;OK
--j TOS --xor-tos 0x12;-j TOS --set-tos 0x12/0x00;OK
--j TOS;;FAIL

extensions/libxt_TPROXY.t

-:PREROUTING
-*mangle
--j TPROXY --on-port 12345 --on-ip 10.0.0.1 --tproxy-mark 0x23/0xff;;FAIL
--p udp -j TPROXY --on-port 12345 --on-ip 10.0.0.1 --tproxy-mark 0x23/0xff;=;OK
--p tcp -m tcp --dport 2342 -j TPROXY --on-port 12345 --on-ip 10.0.0.1 --tproxy-mark 0x23/0xff;=;OK

extensions/libxt_TRACE.t

-:PREROUTING,OUTPUT
-*raw
--j TRACE;=;OK

extensions/libxt_addrtype.t

-:INPUT,FORWARD,OUTPUT
--m addrtype;;FAIL
--m addrtype --src-type wrong;;FAIL
--m addrtype --src-type UNSPEC;=;OK
--m addrtype --dst-type UNSPEC;=;OK
--m addrtype --src-type LOCAL --dst-type LOCAL;=;OK
--m addrtype --dst-type UNSPEC;=;OK
--m addrtype --limit-iface-in;;FAIL
--m addrtype --limit-iface-out;;FAIL
--m addrtype --limit-iface-in --limit-iface-out;;FAIL
--m addrtype --src-type LOCAL --limit-iface-in --limit-iface-out;;FAIL
-:INPUT
--m addrtype --src-type LOCAL --limit-iface-in;=;OK
--m addrtype --dst-type LOCAL --limit-iface-in;=;OK
-:OUTPUT
--m addrtype --src-type LOCAL --limit-iface-out;=;OK
--m addrtype --dst-type LOCAL --limit-iface-out;=;OK

extensions/libxt_bpf.c

@@ -16,11 +16,17 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <xtables.h>
+#include "config.h"
+
+#ifdef HAVE_LINUX_BPF_H
+#include <linux/bpf.h>
+#endif
 
 #define BCODE_FILE_MAX_LEN_B	1024
 
 enum {
 	O_BCODE_STDIN = 0,
+	O_OBJ_PINNED = 1,
 };
 
 static void bpf_help(void)
@@ -28,7 +34,16 @@ static void bpf_help(void)
 	printf(
 "bpf match options:\n"
 "--bytecode <program>	: a bpf program as generated by\n"
-"  `nfbpf_compiler RAW <filter>`\n");
+"                         $(nfbpf_compile RAW '<filter>')\n");
+}
+
+static void bpf_help_v1(void)
+{
+	printf(
+"bpf match options:\n"
+"--bytecode <program>	        : a bpf program as generated by\n"
+"                                 $(nfbpf_compile RAW '<filter>')\n"
+"--object-pinned <bpf object>	: a path to a pinned BPF object in bpf fs\n");
 }
 
 static const struct xt_option_entry bpf_opts[] = {
@@ -36,23 +51,47 @@ static const struct xt_option_entry bpf_opts[] = {
 	XTOPT_TABLEEND,
 };
 
-static void bpf_parse_string(struct xt_option_call *cb, const char *bpf_program,
-			     const char separator)
+static const struct xt_option_entry bpf_opts_v1[] = {
+	{.name = "bytecode", .id = O_BCODE_STDIN, .type = XTTYPE_STRING},
+	{.name = "object-pinned" , .id = O_OBJ_PINNED, .type = XTTYPE_STRING,
+	 .flags = XTOPT_PUT, XTOPT_POINTER(struct xt_bpf_info_v1, path)},
+	XTOPT_TABLEEND,
+};
+
+static int bpf_obj_get(const char *filepath)
 {
-	struct xt_bpf_info *bi = (void *) cb->data;
+#if defined HAVE_LINUX_BPF_H && defined __NR_bpf
+	union bpf_attr attr;
+
+	memset(&attr, 0, sizeof(attr));
+	attr.pathname = (__u64) filepath;
+
+	return syscall(__NR_bpf, BPF_OBJ_GET, &attr, sizeof(attr));
+#else
+	xtables_error(OTHER_PROBLEM,
+		      "No bpf header, kernel headers too old?\n");
+	return -EINVAL;
+#endif
+}
+
+static void bpf_parse_string(struct sock_filter *pc, __u16 *lenp, __u16 len_max,
+			     const char *bpf_program)
+{
+	const char separator = ',';
 	const char *token;
 	char sp;
 	int i;
+	__u16 len;
 
 	/* parse head: length. */
-	if (sscanf(bpf_program, "%hu%c", &bi->bpf_program_num_elem, &sp) != 2 ||
+	if (sscanf(bpf_program, "%hu%c", &len, &sp) != 2 ||
 		   sp != separator)
 		xtables_error(PARAMETER_PROBLEM,
 			      "bpf: error parsing program length");
-	if (!bi->bpf_program_num_elem)
+	if (!len)
 		xtables_error(PARAMETER_PROBLEM,
 			      "bpf: illegal zero length program");
-	if (bi->bpf_program_num_elem > XT_BPF_MAX_NUM_INSTR)
+	if (len > len_max)
 		xtables_error(PARAMETER_PROBLEM,
 			      "bpf: number of instructions exceeds maximum");
 
@@ -60,62 +99,108 @@ static void bpf_parse_string(struct xt_option_call *cb, const char *bpf_program,
 	i = 0;
 	token = bpf_program;
 	while ((token = strchr(token, separator)) && (++token)[0]) {
-		if (i >= bi->bpf_program_num_elem)
+		if (i >= len)
 			xtables_error(PARAMETER_PROBLEM,
 				      "bpf: real program length exceeds"
 				      " the encoded length parameter");
 		if (sscanf(token, "%hu %hhu %hhu %u,",
-			   &bi->bpf_program[i].code,
-			   &bi->bpf_program[i].jt,
-			   &bi->bpf_program[i].jf,
-			   &bi->bpf_program[i].k) != 4)
+			   &pc->code, &pc->jt, &pc->jf, &pc->k) != 4)
 			xtables_error(PARAMETER_PROBLEM,
 				      "bpf: error at instr %d", i);
 		i++;
+		pc++;
 	}
 
-	if (i != bi->bpf_program_num_elem)
+	if (i != len)
 		xtables_error(PARAMETER_PROBLEM,
 			      "bpf: parsed program length is less than the"
 			      " encoded length parameter");
+
+	*lenp = len;
+}
+
+static void bpf_parse_obj_pinned(struct xt_bpf_info_v1 *bi,
+				 const char *filepath)
+{
+	bi->fd = bpf_obj_get(filepath);
+	if (bi->fd < 0)
+		xtables_error(PARAMETER_PROBLEM,
+			      "bpf: failed to get bpf object");
+
+	/* Cannot close bi->fd explicitly. Rely on exit */
+	if (fcntl(bi->fd, F_SETFD, FD_CLOEXEC) == -1) {
+		xtables_error(OTHER_PROBLEM,
+			      "Could not set close on exec: %s\n",
+			      strerror(errno));
+	}
 }
 
 static void bpf_parse(struct xt_option_call *cb)
 {
+	struct xt_bpf_info *bi = (void *) cb->data;
+
 	xtables_option_parse(cb);
 	switch (cb->entry->id) {
 	case O_BCODE_STDIN:
-		bpf_parse_string(cb, cb->arg, ',');
+		bpf_parse_string(bi->bpf_program, &bi->bpf_program_num_elem,
+				 ARRAY_SIZE(bi->bpf_program), cb->arg);
 		break;
 	default:
 		xtables_error(PARAMETER_PROBLEM, "bpf: unknown option");
 	}
 }
 
-static void bpf_print_code(const void *ip, const struct xt_entry_match *match)
+static void bpf_parse_v1(struct xt_option_call *cb)
 {
-	const struct xt_bpf_info *info = (void *) match->data;
-	int i;
+	struct xt_bpf_info_v1 *bi = (void *) cb->data;
+
+	xtables_option_parse(cb);
+	switch (cb->entry->id) {
+	case O_BCODE_STDIN:
+		bpf_parse_string(bi->bpf_program, &bi->bpf_program_num_elem,
+				 ARRAY_SIZE(bi->bpf_program), cb->arg);
+		bi->mode = XT_BPF_MODE_BYTECODE;
+		break;
+	case O_OBJ_PINNED:
+		bpf_parse_obj_pinned(bi, cb->arg);
+		bi->mode = XT_BPF_MODE_FD_PINNED;
+		break;
+	default:
+		xtables_error(PARAMETER_PROBLEM, "bpf: unknown option");
+	}
+}
 
-	for (i = 0; i < info->bpf_program_num_elem-1; i++)
-		printf("%hu %hhu %hhu %u,", info->bpf_program[i].code,
-					    info->bpf_program[i].jt,
-					    info->bpf_program[i].jf,
-					    info->bpf_program[i].k);
+static void bpf_print_code(const struct sock_filter *pc, __u16 len, char tail)
+{
+	for (; len; len--, pc++)
+		printf("%hu %hhu %hhu %u%c",
+		       pc->code, pc->jt, pc->jf, pc->k,
+		       len > 1 ? ',' : tail);
+}
 
-	printf("%hu %hhu %hhu %u", info->bpf_program[i].code,
-				    info->bpf_program[i].jt,
-				    info->bpf_program[i].jf,
-				    info->bpf_program[i].k);
+static void bpf_save_code(const struct sock_filter *pc, __u16 len)
+{
+	printf(" --bytecode \"%hu,", len);
+	bpf_print_code(pc, len, '\"');
 }
 
 static void bpf_save(const void *ip, const struct xt_entry_match *match)
 {
 	const struct xt_bpf_info *info = (void *) match->data;
 
-	printf(" --bytecode \"%hu,", info->bpf_program_num_elem);
-	bpf_print_code(ip, match);
-	printf("\"");
+	bpf_save_code(info->bpf_program, info->bpf_program_num_elem);
+}
+
+static void bpf_save_v1(const void *ip, const struct xt_entry_match *match)
+{
+	const struct xt_bpf_info_v1 *info = (void *) match->data;
+
+	if (info->mode == XT_BPF_MODE_BYTECODE)
+		bpf_save_code(info->bpf_program, info->bpf_program_num_elem);
+	else if (info->mode == XT_BPF_MODE_FD_PINNED)
+		printf(" --object-pinned %s", info->path);
+	else
+		xtables_error(OTHER_PROBLEM, "unknown bpf mode");
 }
 
 static void bpf_fcheck(struct xt_fcheck_call *cb)
@@ -125,28 +210,73 @@ static void bpf_fcheck(struct xt_fcheck_call *cb)
 			      "bpf: missing --bytecode parameter");
 }
 
+static void bpf_fcheck_v1(struct xt_fcheck_call *cb)
+{
+	const unsigned int bit_bcode = 1 << O_BCODE_STDIN;
+	const unsigned int bit_pinned = 1 << O_OBJ_PINNED;
+	unsigned int flags;
+
+	flags = cb->xflags & (bit_bcode | bit_pinned);
+	if (flags != bit_bcode && flags != bit_pinned)
+		xtables_error(PARAMETER_PROBLEM,
+			      "bpf: one of --bytecode or --pinned is required");
+}
+
 static void bpf_print(const void *ip, const struct xt_entry_match *match,
 		      int numeric)
 {
+	const struct xt_bpf_info *info = (void *) match->data;
+
+	printf("match bpf ");
+	bpf_print_code(info->bpf_program, info->bpf_program_num_elem, '\0');
+}
+
+static void bpf_print_v1(const void *ip, const struct xt_entry_match *match,
+			 int numeric)
+{
+	const struct xt_bpf_info_v1 *info = (void *) match->data;
+
 	printf("match bpf ");
-	return bpf_print_code(ip, match);
-}
-
-static struct xtables_match bpf_match = {
-	.family		= NFPROTO_UNSPEC,
-	.name		= "bpf",
-	.version	= XTABLES_VERSION,
-	.size		= XT_ALIGN(sizeof(struct xt_bpf_info)),
-	.userspacesize	= XT_ALIGN(offsetof(struct xt_bpf_info, filter)),
-	.help		= bpf_help,
-	.print		= bpf_print,
-	.save		= bpf_save,
-	.x6_parse	= bpf_parse,
-	.x6_fcheck	= bpf_fcheck,
-	.x6_options	= bpf_opts,
+	if (info->mode == XT_BPF_MODE_BYTECODE)
+		bpf_print_code(info->bpf_program, info->bpf_program_num_elem, '\0');
+	else if (info->mode == XT_BPF_MODE_FD_PINNED)
+		printf("pinned %s", info->path);
+	else
+		printf("unknown");
+}
+
+static struct xtables_match bpf_matches[] = {
+	{
+		.family		= NFPROTO_UNSPEC,
+		.name		= "bpf",
+		.version	= XTABLES_VERSION,
+		.revision	= 0,
+		.size		= XT_ALIGN(sizeof(struct xt_bpf_info)),
+		.userspacesize	= XT_ALIGN(offsetof(struct xt_bpf_info, filter)),
+		.help		= bpf_help,
+		.print		= bpf_print,
+		.save		= bpf_save,
+		.x6_parse	= bpf_parse,
+		.x6_fcheck	= bpf_fcheck,
+		.x6_options	= bpf_opts,
+	},
+	{
+		.family		= NFPROTO_UNSPEC,
+		.name		= "bpf",
+		.version	= XTABLES_VERSION,
+		.revision	= 1,
+		.size		= XT_ALIGN(sizeof(struct xt_bpf_info_v1)),
+		.userspacesize	= XT_ALIGN(offsetof(struct xt_bpf_info_v1, filter)),
+		.help		= bpf_help_v1,
+		.print		= bpf_print_v1,
+		.save		= bpf_save_v1,
+		.x6_parse	= bpf_parse_v1,
+		.x6_fcheck	= bpf_fcheck_v1,
+		.x6_options	= bpf_opts_v1,
+	},
 };
 
 void _init(void)
 {
-	xtables_register_match(&bpf_match);
+	xtables_register_matches(bpf_matches, ARRAY_SIZE(bpf_matches));
 }

extensions/libxt_bpf.man

-Match using Linux Socket Filter. Expects a BPF program in decimal format. This
-is the format generated by the \fBnfbpf_compile\fP utility.
+Match using Linux Socket Filter. Expects a path to an eBPF object or a cBPF
+program in decimal format.
+.TP
+\fB\-\-object\-pinned\fP \fIpath\fP
+Pass a path to a pinned eBPF object.
+.PP
+Applications load eBPF programs into the kernel with the bpf() system call and
+BPF_PROG_LOAD command and can pin them in a virtual filesystem with BPF_OBJ_PIN.
+To use a pinned object in iptables, mount the bpf filesystem using
+.IP
+mount \-t bpf bpf ${BPF_MOUNT}
+.PP
+then insert the filter in iptables by path:
+.IP
+iptables \-A OUTPUT \-m bpf \-\-object\-pinned ${BPF_MOUNT}/{PINNED_PATH} \-j ACCEPT
 .TP
 \fB\-\-bytecode\fP \fIcode\fP
-Pass the BPF byte code format (described in the example below).
+Pass the BPF byte code format as generated by the \fBnfbpf_compile\fP utility.
 .PP
 The code format is similar to the output of the tcpdump -ddd command: one line
 that stores the number of instructions, followed by one line for each