/*

 * q_sfq.c		SFQ.

 *

 *		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:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <string.h>

#include <math.h>

#include "utils.h"

#include "tc_util.h"

#include "tc_red.h"

static void explain(void)

{

	fprintf(stderr,

		"Usage: ... sfq	[ limit NUMBER ] [ perturb SECS ] [ quantum BYTES ]\n"

		"		[ divisor NUMBER ] [ flows NUMBER] [ depth NUMBER ]\n"

		"		[ headdrop ]\n"

		"		[ redflowlimit BYTES ] [ min BYTES ] [ max BYTES ]\n"

		"		[ avpkt BYTES ] [ burst PACKETS ] [ probability P ]\n"

		"		[ ecn ] [ harddrop ]\n");

}

static int sfq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, const char *dev)

{

	int ok = 0, red = 0;

	struct tc_sfq_qopt_v1 opt = {};

	unsigned int burst = 0;

	int wlog;

	unsigned int avpkt = 1000;

	double probability = 0.02;

	while (argc > 0) {

		if (strcmp(*argv, "quantum") == 0) {

			NEXT_ARG();

			if (get_size(&opt.v0.quantum, *argv)) {

				fprintf(stderr, "Illegal \"limit\"\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "perturb") == 0) {

			NEXT_ARG();

			if (get_integer(&opt.v0.perturb_period, *argv, 0)) {

				fprintf(stderr, "Illegal \"perturb\"\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "limit") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.v0.limit, *argv, 0)) {

				fprintf(stderr, "Illegal \"limit\"\n");

				return -1;

			}

			if (opt.v0.limit < 2) {

				fprintf(stderr, "Illegal \"limit\", must be > 1\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "divisor") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.v0.divisor, *argv, 0)) {

				fprintf(stderr, "Illegal \"divisor\"\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "flows") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.v0.flows, *argv, 0)) {

				fprintf(stderr, "Illegal \"flows\"\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "depth") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.depth, *argv, 0)) {

				fprintf(stderr, "Illegal \"flows\"\n");

				return -1;

			}

			ok++;

		} else if (strcmp(*argv, "headdrop") == 0) {

			opt.headdrop = 1;

			ok++;

		} else if (strcmp(*argv, "redflowlimit") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.limit, *argv, 0)) {

				fprintf(stderr, "Illegal \"redflowlimit\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "min") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.qth_min, *argv, 0)) {

				fprintf(stderr, "Illegal \"min\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "max") == 0) {

			NEXT_ARG();

			if (get_u32(&opt.qth_max, *argv, 0)) {

				fprintf(stderr, "Illegal \"max\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "burst") == 0) {

			NEXT_ARG();

			if (get_unsigned(&burst, *argv, 0)) {

				fprintf(stderr, "Illegal \"burst\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "avpkt") == 0) {

			NEXT_ARG();

			if (get_size(&avpkt, *argv)) {

				fprintf(stderr, "Illegal \"avpkt\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "probability") == 0) {

			NEXT_ARG();

			if (sscanf(*argv, "%lg", &probability) != 1) {

				fprintf(stderr, "Illegal \"probability\"\n");

				return -1;

			}

			red++;

		} else if (strcmp(*argv, "ecn") == 0) {

			opt.flags |= TC_RED_ECN;

			red++;

		} else if (strcmp(*argv, "harddrop") == 0) {

			opt.flags |= TC_RED_HARDDROP;

			red++;

		} else if (strcmp(*argv, "help") == 0) {

			explain();

			return -1;

		} else {

			fprintf(stderr, "What is \"%s\"?\n", *argv);

			explain();

			return -1;

		}

		argc--; argv++;

	}

	if (red) {

		if (!opt.limit) {

			fprintf(stderr, "Required parameter (redflowlimit) is missing\n");

			return -1;

		}

		/* Compute default min/max thresholds based on

		   Sally Floyd's recommendations:

		   http://www.icir.org/floyd/REDparameters.txt

		*/

		if (!opt.qth_max)

			opt.qth_max = opt.limit / 4;

		if (!opt.qth_min)

			opt.qth_min = opt.qth_max / 3;

		if (!burst)

			burst = (2 * opt.qth_min + opt.qth_max) / (3 * avpkt);

		if (opt.qth_max > opt.limit) {

			fprintf(stderr, "\"max\" is larger than \"limit\"\n");

			return -1;

		}

		if (opt.qth_min >= opt.qth_max) {

			fprintf(stderr, "\"min\" is not smaller than \"max\"\n");

			return -1;

		}

		wlog = tc_red_eval_ewma(opt.qth_min, burst, avpkt);

		if (wlog < 0) {

			fprintf(stderr, "SFQ: failed to calculate EWMA constant.\n");

			return -1;

		}

		if (wlog >= 10)

			fprintf(stderr, "SFQ: WARNING. Burst %u seems to be too large.\n", burst);

		opt.Wlog = wlog;

		wlog = tc_red_eval_P(opt.qth_min, opt.qth_max, probability);

		if (wlog < 0) {

			fprintf(stderr, "SFQ: failed to calculate probability.\n");

			return -1;

		}

		opt.Plog = wlog;

		opt.max_P = probability * pow(2, 32);

	}

	if (ok || red)

		addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));

	return 0;

}

static int sfq_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)

{

	struct tc_sfq_qopt *qopt;

	struct tc_sfq_qopt_v1 *qopt_ext = NULL;

	SPRINT_BUF(b1);

	SPRINT_BUF(b2);

	SPRINT_BUF(b3);

	if (opt == NULL)

		return 0;

	if (RTA_PAYLOAD(opt)  < sizeof(*qopt))

		return -1;

	if (RTA_PAYLOAD(opt) >= sizeof(*qopt_ext))

		qopt_ext = RTA_DATA(opt);

	qopt = RTA_DATA(opt);

	fprintf(f, "limit %up ", qopt->limit);

	fprintf(f, "quantum %s ", sprint_size(qopt->quantum, b1));

	if (qopt_ext && qopt_ext->depth)

		fprintf(f, "depth %u ", qopt_ext->depth);

	if (qopt_ext && qopt_ext->headdrop)

		fprintf(f, "headdrop ");

	if (show_details) {

		fprintf(f, "flows %u/%u ", qopt->flows, qopt->divisor);

	}

	fprintf(f, "divisor %u ", qopt->divisor);

	if (qopt->perturb_period)

		fprintf(f, "perturb %dsec ", qopt->perturb_period);

	if (qopt_ext && qopt_ext->qth_min) {

		fprintf(f, "\n ewma %u ", qopt_ext->Wlog);

		fprintf(f, "min %s max %s probability %g ",

			sprint_size(qopt_ext->qth_min, b2),

			sprint_size(qopt_ext->qth_max, b3),

			qopt_ext->max_P / pow(2, 32));

		tc_red_print_flags(qopt_ext->flags);

		if (show_stats) {

			fprintf(f, "\n prob_mark %u prob_mark_head %u prob_drop %u",

				qopt_ext->stats.prob_mark,

				qopt_ext->stats.prob_mark_head,

				qopt_ext->stats.prob_drop);

			fprintf(f, "\n forced_mark %u forced_mark_head %u forced_drop %u",

				qopt_ext->stats.forced_mark,

				qopt_ext->stats.forced_mark_head,

				qopt_ext->stats.forced_drop);

		}

	}

	return 0;

}

static int sfq_print_xstats(struct qdisc_util *qu, FILE *f,

			    struct rtattr *xstats)

{

	struct tc_sfq_xstats *st;

	if (xstats == NULL)

		return 0;

	if (RTA_PAYLOAD(xstats) < sizeof(*st))

		return -1;

	st = RTA_DATA(xstats);

	fprintf(f, " allot %d ", st->allot);

	fprintf(f, "\n");

	return 0;

}

struct qdisc_util sfq_qdisc_util = {

	.id		= "sfq",

	.parse_qopt	= sfq_parse_opt,

	.print_qopt	= sfq_print_opt,

	.print_xstats	= sfq_print_xstats,

};