tc/q_netem.c - maze/iproute2 - Git at Google

 /*
  * q_netem.c		NETEM.
  *
  *		This program is free software; you can redistribute 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.
  *
  * Authors:	Stephen Hemminger <shemminger@osdl.org>
  *
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <syslog.h>
 #include <fcntl.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <string.h>
 #include <errno.h>

 #include "utils.h"
 #include "tc_util.h"
 #include "tc_common.h"

 static void explain(void)
 {
 	fprintf(stderr,
 "Usage: ... netem [ limit PACKETS ] \n" \
 "                 [ delay TIME [ JITTER [CORRELATION]]]\n" \
 "                 [ distribution {uniform|normal|pareto|paretonormal} ]\n" \
 "                 [ drop PERCENT [CORRELATION]] \n" \
 "                 [ corrupt PERCENT [CORRELATION]] \n" \
 "                 [ duplicate PERCENT [CORRELATION]]\n" \
 "                 [ reorder PRECENT [CORRELATION] [ gap DISTANCE ]]\n");
 }

 static void explain1(const char *arg)
 {
 	fprintf(stderr, "Illegal \"%s\"\n", arg);
 }

 /* Upper bound on size of distribution
  *  really (TCA_BUF_MAX - other headers) / sizeof (__s16)
  */
 #define MAX_DIST	(16*1024)

 /*
  * Simplistic file parser for distrbution data.
  * Format is:
  *	# comment line(s)
  *	data0 data1 ...
  */
 static int get_distribution(const char *type, __s16 *data, int maxdata)
 {
 	FILE *f;
 	int n;
 	long x;
 	size_t len;
 	char *line = NULL;
 	char name[128];

 	snprintf(name, sizeof(name), "%s/%s.dist", get_tc_lib(), type);
 	if ((f = fopen(name, "r")) == NULL) {
 		fprintf(stderr, "No distribution data for %s (%s: %s)\n",
 			type, name, strerror(errno));
 		return -1;
 	}

 	n = 0;
 	while (getline(&line, &len, f) != -1) {
 		char *p, *endp;
 		if (*line == '\n' || *line == '#')
 			continue;

 		for (p = line; ; p = endp) {
 			x = strtol(p, &endp, 0);
 			if (endp == p)
 				break;

 			if (n >= maxdata) {
 				fprintf(stderr, "%s: too much data\n",
 					name);
 				n = -1;
 				goto error;
 			}
 			data[n++] = x;
 		}
 	}
  error:
 	free(line);
 	fclose(f);
 	return n;
 }

 static int isnumber(const char *arg)
 {
 	char *p;

 	return strtod(arg, &p) != 0 || p != arg;
 }

 #define NEXT_IS_NUMBER() (NEXT_ARG_OK() && isnumber(argv[1]))

 /* Adjust for the fact that psched_ticks aren't always usecs
    (based on kernel PSCHED_CLOCK configuration */
 static int get_ticks(__u32 *ticks, const char *str)
 {
 	unsigned t;

 	if(get_time(&t, str))
 		return -1;

 	if (tc_core_time2big(t)) {
 		fprintf(stderr, "Illegal %u time (too large)\n", t);
 		return -1;
 	}

 	*ticks = tc_core_time2tick(t);
 	return 0;
 }

 static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 			   struct nlmsghdr *n)
 {
 	size_t dist_size = 0;
 	struct rtattr *tail;
 	struct tc_netem_qopt opt;
 	struct tc_netem_corr cor;
 	struct tc_netem_reorder reorder;
 	struct tc_netem_corrupt corrupt;
 	__s16 *dist_data = NULL;
 	int present[__TCA_NETEM_MAX];

 	memset(&opt, 0, sizeof(opt));
 	opt.limit = 1000;
 	memset(&cor, 0, sizeof(cor));
 	memset(&reorder, 0, sizeof(reorder));
 	memset(&corrupt, 0, sizeof(corrupt));
 	memset(present, 0, sizeof(present));

 	while (argc > 0) {
 		if (matches(*argv, "limit") == 0) {
 			NEXT_ARG();
 			if (get_size(&opt.limit, *argv)) {
 				explain1("limit");
 				return -1;
 			}
 		} else if (matches(*argv, "latency") == 0 ||
 			   matches(*argv, "delay") == 0) {
 			NEXT_ARG();
 			if (get_ticks(&opt.latency, *argv)) {
 				explain1("latency");
 				return -1;
 			}

 			if (NEXT_IS_NUMBER()) {
 				NEXT_ARG();
 				if (get_ticks(&opt.jitter, *argv)) {
 					explain1("latency");
 					return -1;
 				}

 				if (NEXT_IS_NUMBER()) {
 					NEXT_ARG();
 					++present[TCA_NETEM_CORR];
 					if (get_percent(&cor.delay_corr,							*argv)) {
 						explain1("latency");
 						return -1;
 					}
 				}
 			}
 		} else if (matches(*argv, "loss") == 0 ||
 			   matches(*argv, "drop") == 0) {
 			NEXT_ARG();
 			if (get_percent(&opt.loss, *argv)) {
 				explain1("loss");
 				return -1;
 			}
 			if (NEXT_IS_NUMBER()) {
 				NEXT_ARG();
 				++present[TCA_NETEM_CORR];
 				if (get_percent(&cor.loss_corr, *argv)) {
 					explain1("loss");
 					return -1;
 				}
 			}
 		} else if (matches(*argv, "reorder") == 0) {
 			NEXT_ARG();
 			present[TCA_NETEM_REORDER] = 1;
 			if (get_percent(&reorder.probability, *argv)) {
 				explain1("reorder");
 				return -1;
 			}
 			if (NEXT_IS_NUMBER()) {
 				NEXT_ARG();
 				++present[TCA_NETEM_CORR];
 				if (get_percent(&reorder.correlation, *argv)) {
 					explain1("reorder");
 					return -1;
 				}
 			}
 		} else if (matches(*argv, "corrupt") == 0) {
 			NEXT_ARG();
 			present[TCA_NETEM_CORRUPT] = 1;
 			if (get_percent(&corrupt.probability, *argv)) {
 				explain1("corrupt");
 				return -1;
 			}
 			if (NEXT_IS_NUMBER()) {
 				NEXT_ARG();
 				++present[TCA_NETEM_CORR];
 				if (get_percent(&corrupt.correlation, *argv)) {
 					explain1("corrupt");
 					return -1;
 				}
 			}
 		} else if (matches(*argv, "gap") == 0) {
 			NEXT_ARG();
 			if (get_u32(&opt.gap, *argv, 0)) {
 				explain1("gap");
 				return -1;
 			}
 		} else if (matches(*argv, "duplicate") == 0) {
 			NEXT_ARG();
 			if (get_percent(&opt.duplicate, *argv)) {
 				explain1("duplicate");
 				return -1;
 			}
 			if (NEXT_IS_NUMBER()) {
 				NEXT_ARG();
 				if (get_percent(&cor.dup_corr, *argv)) {
 					explain1("duplicate");
 					return -1;
 				}
 			}
 		} else if (matches(*argv, "distribution") == 0) {
 			NEXT_ARG();
 			dist_data = calloc(sizeof(dist_data[0]), MAX_DIST);
 			dist_size = get_distribution(*argv, dist_data, MAX_DIST);
 			if (dist_size <= 0) {
 				free(dist_data);
 				return -1;
 			}
 		} else if (strcmp(*argv, "help") == 0) {
 			explain();
 			return -1;
 		} else {
 			fprintf(stderr, "What is \"%s\"?\n", *argv);
 			explain();
 			return -1;
 		}
 		argc--; argv++;
 	}

 	tail = NLMSG_TAIL(n);

 	if (reorder.probability) {
 		if (opt.latency == 0) {
 			fprintf(stderr, "reordering not possible without specifying some delay\n");
 		}
 		if (opt.gap == 0)
 			opt.gap = 1;
 	} else if (opt.gap > 0) {
 		fprintf(stderr, "gap specified without reorder probability\n");
 		explain();
 		return -1;
 	}

 	if (dist_data && (opt.latency == 0 || opt.jitter == 0)) {
 		fprintf(stderr, "distribution specified but no latency and jitter values\n");
 		explain();
 		return -1;
 	}

 	if (addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt)) < 0)
 		return -1;

 	if (present[TCA_NETEM_CORR] &&
 	    addattr_l(n, 1024, TCA_NETEM_CORR, &cor, sizeof(cor)) < 0)
 			return -1;

 	if (present[TCA_NETEM_REORDER] &&
 	    addattr_l(n, 1024, TCA_NETEM_REORDER, &reorder, sizeof(reorder)) < 0)
 		return -1;

 	if (present[TCA_NETEM_CORRUPT] &&
 	    addattr_l(n, 1024, TCA_NETEM_CORRUPT, &corrupt, sizeof(corrupt)) < 0)
 		return -1;

 	if (dist_data) {
 		if (addattr_l(n, MAX_DIST * sizeof(dist_data[0]),
 			      TCA_NETEM_DELAY_DIST,
 			      dist_data, dist_size * sizeof(dist_data[0])) < 0)
 			return -1;
 		free(dist_data);
 	}
 	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 	return 0;
 }

 static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 {
 	const struct tc_netem_corr *cor = NULL;
 	const struct tc_netem_reorder *reorder = NULL;
 	const struct tc_netem_corrupt *corrupt = NULL;
 	struct tc_netem_qopt qopt;
 	int len = RTA_PAYLOAD(opt) - sizeof(qopt);
 	SPRINT_BUF(b1);

 	if (opt == NULL)
 		return 0;

 	if (len < 0) {
 		fprintf(stderr, "options size error\n");
 		return -1;
 	}
 	memcpy(&qopt, RTA_DATA(opt), sizeof(qopt));

 	if (len > 0) {
 		struct rtattr *tb[TCA_NETEM_MAX+1];
 		parse_rtattr(tb, TCA_NETEM_MAX, RTA_DATA(opt) + sizeof(qopt),
 			     len);

 		if (tb[TCA_NETEM_CORR]) {
 			if (RTA_PAYLOAD(tb[TCA_NETEM_CORR]) < sizeof(*cor))
 				return -1;
 			cor = RTA_DATA(tb[TCA_NETEM_CORR]);
 		}
 		if (tb[TCA_NETEM_REORDER]) {
 			if (RTA_PAYLOAD(tb[TCA_NETEM_REORDER]) < sizeof(*reorder))
 				return -1;
 			reorder = RTA_DATA(tb[TCA_NETEM_REORDER]);
 		}
 		if (tb[TCA_NETEM_CORRUPT]) {
 			if (RTA_PAYLOAD(tb[TCA_NETEM_CORRUPT]) < sizeof(*corrupt))
 				return -1;
 			corrupt = RTA_DATA(tb[TCA_NETEM_CORRUPT]);
 		}
 	}

 	fprintf(f, "limit %d", qopt.limit);

 	if (qopt.latency) {
 		fprintf(f, " delay %s", sprint_ticks(qopt.latency, b1));

 		if (qopt.jitter) {
 			fprintf(f, "  %s", sprint_ticks(qopt.jitter, b1));
 			if (cor && cor->delay_corr)
 				fprintf(f, " %s", sprint_percent(cor->delay_corr, b1));
 		}
 	}

 	if (qopt.loss) {
 		fprintf(f, " loss %s", sprint_percent(qopt.loss, b1));
 		if (cor && cor->loss_corr)
 			fprintf(f, " %s", sprint_percent(cor->loss_corr, b1));
 	}

 	if (qopt.duplicate) {
 		fprintf(f, " duplicate %s",
 			sprint_percent(qopt.duplicate, b1));
 		if (cor && cor->dup_corr)
 			fprintf(f, " %s", sprint_percent(cor->dup_corr, b1));
 	}

 	if (reorder && reorder->probability) {
 		fprintf(f, " reorder %s",
 			sprint_percent(reorder->probability, b1));
 		if (reorder->correlation)
 			fprintf(f, " %s",
 				sprint_percent(reorder->correlation, b1));
 	}

 	if (corrupt && corrupt->probability) {
 		fprintf(f, " corrupt %s",
 			sprint_percent(corrupt->probability, b1));
 		if (corrupt->correlation)
 			fprintf(f, " %s",
 				sprint_percent(corrupt->correlation, b1));
 	}

 	if (qopt.gap)
 		fprintf(f, " gap %lu", (unsigned long)qopt.gap);

 	return 0;
 }

 struct qdisc_util netem_qdisc_util = {
 	.id	   	= "netem",
 	.parse_qopt	= netem_parse_opt,
 	.print_qopt	= netem_print_opt,
 };
	/*
	* q_netem.c NETEM.
	*
	* This program is free software; you can redistribute 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.
	*
	* Authors: Stephen Hemminger <shemminger@osdl.org>
	*
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <syslog.h>
	#include <fcntl.h>
	#include <sys/socket.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <string.h>
	#include <errno.h>

	#include "utils.h"
	#include "tc_util.h"
	#include "tc_common.h"

	static void explain(void)
	{
	fprintf(stderr,
	"Usage: ... netem [ limit PACKETS ] \n" \
	" [ delay TIME [ JITTER [CORRELATION]]]\n" \
	" [ distribution {uniform\|normal\|pareto\|paretonormal} ]\n" \
	" [ drop PERCENT [CORRELATION]] \n" \
	" [ corrupt PERCENT [CORRELATION]] \n" \
	" [ duplicate PERCENT [CORRELATION]]\n" \
	" [ reorder PRECENT [CORRELATION] [ gap DISTANCE ]]\n");
	}

	static void explain1(const char *arg)
	{
	fprintf(stderr, "Illegal \"%s\"\n", arg);
	}

	/* Upper bound on size of distribution
	* really (TCA_BUF_MAX - other headers) / sizeof (__s16)
	*/
	#define MAX_DIST (16*1024)

	/*
	* Simplistic file parser for distrbution data.
	* Format is:
	* # comment line(s)
	* data0 data1 ...
	*/
	static int get_distribution(const char type, __s16 data, int maxdata)
	{
	FILE *f;
	int n;
	long x;
	size_t len;
	char *line = NULL;
	char name[128];

	snprintf(name, sizeof(name), "%s/%s.dist", get_tc_lib(), type);
	if ((f = fopen(name, "r")) == NULL) {
	fprintf(stderr, "No distribution data for %s (%s: %s)\n",
	type, name, strerror(errno));
	return -1;
	}

	n = 0;
	while (getline(&line, &len, f) != -1) {
	char p, endp;
	if (line == '\n' \|\| line == '#')
	continue;

	for (p = line; ; p = endp) {
	x = strtol(p, &endp, 0);
	if (endp == p)
	break;

	if (n >= maxdata) {
	fprintf(stderr, "%s: too much data\n",
	name);
	n = -1;
	goto error;
	}
	data[n++] = x;
	}
	}
	error:
	free(line);
	fclose(f);
	return n;
	}

	static int isnumber(const char *arg)
	{
	char *p;

	return strtod(arg, &p) != 0 \|\| p != arg;
	}

	#define NEXT_IS_NUMBER() (NEXT_ARG_OK() && isnumber(argv[1]))

	/* Adjust for the fact that psched_ticks aren't always usecs
	(based on kernel PSCHED_CLOCK configuration */
	static int get_ticks(__u32 ticks, const char str)
	{
	unsigned t;

	if(get_time(&t, str))
	return -1;

	if (tc_core_time2big(t)) {
	fprintf(stderr, "Illegal %u time (too large)\n", t);
	return -1;
	}

	*ticks = tc_core_time2tick(t);
	return 0;
	}

	static int netem_parse_opt(struct qdisc_util qu, int argc, char *argv,
	struct nlmsghdr *n)
	{
	size_t dist_size = 0;
	struct rtattr *tail;
	struct tc_netem_qopt opt;
	struct tc_netem_corr cor;
	struct tc_netem_reorder reorder;
	struct tc_netem_corrupt corrupt;
	__s16 *dist_data = NULL;
	int present[__TCA_NETEM_MAX];

	memset(&opt, 0, sizeof(opt));
	opt.limit = 1000;
	memset(&cor, 0, sizeof(cor));
	memset(&reorder, 0, sizeof(reorder));
	memset(&corrupt, 0, sizeof(corrupt));
	memset(present, 0, sizeof(present));

	while (argc > 0) {
	if (matches(*argv, "limit") == 0) {
	NEXT_ARG();
	if (get_size(&opt.limit, *argv)) {
	explain1("limit");
	return -1;
	}
	} else if (matches(*argv, "latency") == 0 \|\|
	matches(*argv, "delay") == 0) {
	NEXT_ARG();
	if (get_ticks(&opt.latency, *argv)) {
	explain1("latency");
	return -1;
	}

	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	if (get_ticks(&opt.jitter, *argv)) {
	explain1("latency");
	return -1;
	}

	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	++present[TCA_NETEM_CORR];
	if (get_percent(&cor.delay_corr, *argv)) {
	explain1("latency");
	return -1;
	}
	}
	}
	} else if (matches(*argv, "loss") == 0 \|\|
	matches(*argv, "drop") == 0) {
	NEXT_ARG();
	if (get_percent(&opt.loss, *argv)) {
	explain1("loss");
	return -1;
	}
	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	++present[TCA_NETEM_CORR];
	if (get_percent(&cor.loss_corr, *argv)) {
	explain1("loss");
	return -1;
	}
	}
	} else if (matches(*argv, "reorder") == 0) {
	NEXT_ARG();
	present[TCA_NETEM_REORDER] = 1;
	if (get_percent(&reorder.probability, *argv)) {
	explain1("reorder");
	return -1;
	}
	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	++present[TCA_NETEM_CORR];
	if (get_percent(&reorder.correlation, *argv)) {
	explain1("reorder");
	return -1;
	}
	}
	} else if (matches(*argv, "corrupt") == 0) {
	NEXT_ARG();
	present[TCA_NETEM_CORRUPT] = 1;
	if (get_percent(&corrupt.probability, *argv)) {
	explain1("corrupt");
	return -1;
	}
	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	++present[TCA_NETEM_CORR];
	if (get_percent(&corrupt.correlation, *argv)) {
	explain1("corrupt");
	return -1;
	}
	}
	} else if (matches(*argv, "gap") == 0) {
	NEXT_ARG();
	if (get_u32(&opt.gap, *argv, 0)) {
	explain1("gap");
	return -1;
	}
	} else if (matches(*argv, "duplicate") == 0) {
	NEXT_ARG();
	if (get_percent(&opt.duplicate, *argv)) {
	explain1("duplicate");
	return -1;
	}
	if (NEXT_IS_NUMBER()) {
	NEXT_ARG();
	if (get_percent(&cor.dup_corr, *argv)) {
	explain1("duplicate");
	return -1;
	}
	}
	} else if (matches(*argv, "distribution") == 0) {
	NEXT_ARG();
	dist_data = calloc(sizeof(dist_data[0]), MAX_DIST);
	dist_size = get_distribution(*argv, dist_data, MAX_DIST);
	if (dist_size <= 0) {
	free(dist_data);
	return -1;
	}
	} else if (strcmp(*argv, "help") == 0) {
	explain();
	return -1;
	} else {
	fprintf(stderr, "What is \"%s\"?\n", *argv);
	explain();
	return -1;
	}
	argc--; argv++;
	}

	tail = NLMSG_TAIL(n);

	if (reorder.probability) {
	if (opt.latency == 0) {
	fprintf(stderr, "reordering not possible without specifying some delay\n");
	}
	if (opt.gap == 0)
	opt.gap = 1;
	} else if (opt.gap > 0) {
	fprintf(stderr, "gap specified without reorder probability\n");
	explain();
	return -1;
	}

	if (dist_data && (opt.latency == 0 \|\| opt.jitter == 0)) {
	fprintf(stderr, "distribution specified but no latency and jitter values\n");
	explain();
	return -1;
	}

	if (addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt)) < 0)
	return -1;

	if (present[TCA_NETEM_CORR] &&
	addattr_l(n, 1024, TCA_NETEM_CORR, &cor, sizeof(cor)) < 0)
	return -1;

	if (present[TCA_NETEM_REORDER] &&
	addattr_l(n, 1024, TCA_NETEM_REORDER, &reorder, sizeof(reorder)) < 0)
	return -1;

	if (present[TCA_NETEM_CORRUPT] &&
	addattr_l(n, 1024, TCA_NETEM_CORRUPT, &corrupt, sizeof(corrupt)) < 0)
	return -1;

	if (dist_data) {
	if (addattr_l(n, MAX_DIST * sizeof(dist_data[0]),
	TCA_NETEM_DELAY_DIST,
	dist_data, dist_size * sizeof(dist_data[0])) < 0)
	return -1;
	free(dist_data);
	}
	tail->rta_len = (void ) NLMSG_TAIL(n) - (void ) tail;
	return 0;
	}

	static int netem_print_opt(struct qdisc_util qu, FILE f, struct rtattr *opt)
	{
	const struct tc_netem_corr *cor = NULL;
	const struct tc_netem_reorder *reorder = NULL;
	const struct tc_netem_corrupt *corrupt = NULL;
	struct tc_netem_qopt qopt;
	int len = RTA_PAYLOAD(opt) - sizeof(qopt);
	SPRINT_BUF(b1);

	if (opt == NULL)
	return 0;

	if (len < 0) {
	fprintf(stderr, "options size error\n");
	return -1;
	}
	memcpy(&qopt, RTA_DATA(opt), sizeof(qopt));

	if (len > 0) {
	struct rtattr *tb[TCA_NETEM_MAX+1];
	parse_rtattr(tb, TCA_NETEM_MAX, RTA_DATA(opt) + sizeof(qopt),
	len);

	if (tb[TCA_NETEM_CORR]) {
	if (RTA_PAYLOAD(tb[TCA_NETEM_CORR]) < sizeof(*cor))
	return -1;
	cor = RTA_DATA(tb[TCA_NETEM_CORR]);
	}
	if (tb[TCA_NETEM_REORDER]) {
	if (RTA_PAYLOAD(tb[TCA_NETEM_REORDER]) < sizeof(*reorder))
	return -1;
	reorder = RTA_DATA(tb[TCA_NETEM_REORDER]);
	}
	if (tb[TCA_NETEM_CORRUPT]) {
	if (RTA_PAYLOAD(tb[TCA_NETEM_CORRUPT]) < sizeof(*corrupt))
	return -1;
	corrupt = RTA_DATA(tb[TCA_NETEM_CORRUPT]);
	}
	}

	fprintf(f, "limit %d", qopt.limit);

	if (qopt.latency) {
	fprintf(f, " delay %s", sprint_ticks(qopt.latency, b1));

	if (qopt.jitter) {
	fprintf(f, " %s", sprint_ticks(qopt.jitter, b1));
	if (cor && cor->delay_corr)
	fprintf(f, " %s", sprint_percent(cor->delay_corr, b1));
	}
	}

	if (qopt.loss) {
	fprintf(f, " loss %s", sprint_percent(qopt.loss, b1));
	if (cor && cor->loss_corr)
	fprintf(f, " %s", sprint_percent(cor->loss_corr, b1));
	}

	if (qopt.duplicate) {
	fprintf(f, " duplicate %s",
	sprint_percent(qopt.duplicate, b1));
	if (cor && cor->dup_corr)
	fprintf(f, " %s", sprint_percent(cor->dup_corr, b1));
	}

	if (reorder && reorder->probability) {
	fprintf(f, " reorder %s",
	sprint_percent(reorder->probability, b1));
	if (reorder->correlation)
	fprintf(f, " %s",
	sprint_percent(reorder->correlation, b1));
	}

	if (corrupt && corrupt->probability) {
	fprintf(f, " corrupt %s",
	sprint_percent(corrupt->probability, b1));
	if (corrupt->correlation)
	fprintf(f, " %s",
	sprint_percent(corrupt->correlation, b1));
	}

	if (qopt.gap)
	fprintf(f, " gap %lu", (unsigned long)qopt.gap);

	return 0;
	}

	struct qdisc_util netem_qdisc_util = {
	.id = "netem",
	.parse_qopt = netem_parse_opt,
	.print_qopt = netem_print_opt,
	};