1/*
2 * Copyright (c) 2008-2013 Patrick McHardy <kaber@trash.net>
3 */
4
5#include <stdio.h>
6#include <string.h>
7#include <stdlib.h>
8#include <math.h>
9
10#include <xtables.h>
11#include <linux/netfilter/x_tables.h>
12#include <linux/netfilter/xt_RATEEST.h>
13
14struct rateest_tg_udata {
15	unsigned int interval;
16	unsigned int ewma_log;
17};
18
19static void
20RATEEST_help(void)
21{
22	printf(
23"RATEEST target options:\n"
24"  --rateest-name name		Rate estimator name\n"
25"  --rateest-interval sec	Rate measurement interval in seconds\n"
26"  --rateest-ewmalog value	Rate measurement averaging time constant\n");
27}
28
29enum {
30	O_NAME = 0,
31	O_INTERVAL,
32	O_EWMALOG,
33};
34
35#define s struct xt_rateest_target_info
36static const struct xt_option_entry RATEEST_opts[] = {
37	{.name = "rateest-name", .id = O_NAME, .type = XTTYPE_STRING,
38	 .flags = XTOPT_MAND | XTOPT_PUT, XTOPT_POINTER(s, name)},
39	{.name = "rateest-interval", .id = O_INTERVAL, .type = XTTYPE_STRING,
40	 .flags = XTOPT_MAND},
41	{.name = "rateest-ewmalog", .id = O_EWMALOG, .type = XTTYPE_STRING,
42	 .flags = XTOPT_MAND},
43	XTOPT_TABLEEND,
44};
45#undef s
46
47/* Copied from iproute */
48#define TIME_UNITS_PER_SEC	1000000
49
50static int
51RATEEST_get_time(unsigned int *time, const char *str)
52{
53	double t;
54	char *p;
55
56	t = strtod(str, &p);
57	if (p == str)
58		return -1;
59
60	if (*p) {
61		if (strcasecmp(p, "s") == 0 || strcasecmp(p, "sec")==0 ||
62		    strcasecmp(p, "secs")==0)
63			t *= TIME_UNITS_PER_SEC;
64		else if (strcasecmp(p, "ms") == 0 || strcasecmp(p, "msec")==0 ||
65			 strcasecmp(p, "msecs") == 0)
66			t *= TIME_UNITS_PER_SEC/1000;
67		else if (strcasecmp(p, "us") == 0 || strcasecmp(p, "usec")==0 ||
68			 strcasecmp(p, "usecs") == 0)
69			t *= TIME_UNITS_PER_SEC/1000000;
70		else
71			return -1;
72	}
73
74	*time = t;
75	return 0;
76}
77
78static void
79RATEEST_print_time(unsigned int time)
80{
81	double tmp = time;
82
83	if (tmp >= TIME_UNITS_PER_SEC)
84		printf(" %.1fs", tmp / TIME_UNITS_PER_SEC);
85	else if (tmp >= TIME_UNITS_PER_SEC/1000)
86		printf(" %.1fms", tmp / (TIME_UNITS_PER_SEC / 1000));
87	else
88		printf(" %uus", time);
89}
90
91static void RATEEST_parse(struct xt_option_call *cb)
92{
93	struct rateest_tg_udata *udata = cb->udata;
94
95	xtables_option_parse(cb);
96	switch (cb->entry->id) {
97	case O_INTERVAL:
98		if (RATEEST_get_time(&udata->interval, cb->arg) < 0)
99			xtables_error(PARAMETER_PROBLEM,
100				   "RATEEST: bad interval value \"%s\"",
101				   cb->arg);
102		break;
103	case O_EWMALOG:
104		if (RATEEST_get_time(&udata->ewma_log, cb->arg) < 0)
105			xtables_error(PARAMETER_PROBLEM,
106				   "RATEEST: bad ewmalog value \"%s\"",
107				   cb->arg);
108		break;
109	}
110}
111
112static void RATEEST_final_check(struct xt_fcheck_call *cb)
113{
114	struct xt_rateest_target_info *info = cb->data;
115	struct rateest_tg_udata *udata = cb->udata;
116
117	for (info->interval = 0; info->interval <= 5; info->interval++) {
118		if (udata->interval <= (1 << info->interval) * (TIME_UNITS_PER_SEC / 4))
119			break;
120	}
121
122	if (info->interval > 5)
123		xtables_error(PARAMETER_PROBLEM,
124			   "RATEEST: interval value is too large");
125	info->interval -= 2;
126
127	for (info->ewma_log = 1; info->ewma_log < 32; info->ewma_log++) {
128		double w = 1.0 - 1.0 / (1 << info->ewma_log);
129		if (udata->interval / (-log(w)) > udata->ewma_log)
130			break;
131	}
132	info->ewma_log--;
133
134	if (info->ewma_log == 0 || info->ewma_log >= 31)
135		xtables_error(PARAMETER_PROBLEM,
136			   "RATEEST: ewmalog value is out of range");
137}
138
139static void
140__RATEEST_print(const struct xt_entry_target *target, const char *prefix)
141{
142	const struct xt_rateest_target_info *info = (const void *)target->data;
143	unsigned int local_interval;
144	unsigned int local_ewma_log;
145
146	local_interval = (TIME_UNITS_PER_SEC << (info->interval + 2)) / 4;
147	local_ewma_log = local_interval * (1 << (info->ewma_log));
148
149	printf(" %sname %s", prefix, info->name);
150	printf(" %sinterval", prefix);
151	RATEEST_print_time(local_interval);
152	printf(" %sewmalog", prefix);
153	RATEEST_print_time(local_ewma_log);
154}
155
156static void
157RATEEST_print(const void *ip, const struct xt_entry_target *target,
158	      int numeric)
159{
160	__RATEEST_print(target, "");
161}
162
163static void
164RATEEST_save(const void *ip, const struct xt_entry_target *target)
165{
166	__RATEEST_print(target, "--rateest-");
167}
168
169static struct xtables_target rateest_tg_reg = {
170	.family		= NFPROTO_UNSPEC,
171	.name		= "RATEEST",
172	.version	= XTABLES_VERSION,
173	.size		= XT_ALIGN(sizeof(struct xt_rateest_target_info)),
174	.userspacesize	= offsetof(struct xt_rateest_target_info, est),
175	.help		= RATEEST_help,
176	.x6_parse	= RATEEST_parse,
177	.x6_fcheck	= RATEEST_final_check,
178	.print		= RATEEST_print,
179	.save		= RATEEST_save,
180	.x6_options	= RATEEST_opts,
181	.udata_size	= sizeof(struct rateest_tg_udata),
182};
183
184void _init(void)
185{
186	xtables_register_target(&rateest_tg_reg);
187}
188