libxt_RATEEST.c revision 622abc73b097e7e778b432e422fd3c1f035bcfd3 
1#include <stdio.h>
2#include <string.h>
3#include <stdlib.h>
4#include <math.h>
5
6#include <xtables.h>
7#include <linux/netfilter/x_tables.h>
8#include <linux/netfilter/xt_RATEEST.h>
9
10struct rateest_tg_udata {
11	unsigned int interval;
12	unsigned int ewma_log;
13};
14
15static void
16RATEEST_help(void)
17{
18	printf(
19"RATEEST target options:\n"
20"  --rateest-name name		Rate estimator name\n"
21"  --rateest-interval sec	Rate measurement interval in seconds\n"
22"  --rateest-ewmalog value	Rate measurement averaging time constant\n");
23}
24
25enum {
26	O_NAME = 0,
27	O_INTERVAL,
28	O_EWMALOG,
29};
30
31#define s struct xt_rateest_target_info
32static const struct xt_option_entry RATEEST_opts[] = {
33	{.name = "rateest-name", .id = O_NAME, .type = XTTYPE_STRING,
34	 .flags = XTOPT_MAND | XTOPT_PUT, XTOPT_POINTER(s, name)},
35	{.name = "rateest-interval", .id = O_INTERVAL, .type = XTTYPE_STRING,
36	 .flags = XTOPT_MAND},
37	{.name = "rateest-ewmalog", .id = O_EWMALOG, .type = XTTYPE_STRING,
38	 .flags = XTOPT_MAND},
39	XTOPT_TABLEEND,
40};
41#undef s
42
43/* Copied from iproute */
44#define TIME_UNITS_PER_SEC	1000000
45
46static int
47RATEEST_get_time(unsigned int *time, const char *str)
48{
49	double t;
50	char *p;
51
52	t = strtod(str, &p);
53	if (p == str)
54		return -1;
55
56	if (*p) {
57		if (strcasecmp(p, "s") == 0 || strcasecmp(p, "sec")==0 ||
58		    strcasecmp(p, "secs")==0)
59			t *= TIME_UNITS_PER_SEC;
60		else if (strcasecmp(p, "ms") == 0 || strcasecmp(p, "msec")==0 ||
61			 strcasecmp(p, "msecs") == 0)
62			t *= TIME_UNITS_PER_SEC/1000;
63		else if (strcasecmp(p, "us") == 0 || strcasecmp(p, "usec")==0 ||
64			 strcasecmp(p, "usecs") == 0)
65			t *= TIME_UNITS_PER_SEC/1000000;
66		else
67			return -1;
68	}
69
70	*time = t;
71	return 0;
72}
73
74static void
75RATEEST_print_time(unsigned int time)
76{
77	double tmp = time;
78
79	if (tmp >= TIME_UNITS_PER_SEC)
80		printf(" %.1fs", tmp / TIME_UNITS_PER_SEC);
81	else if (tmp >= TIME_UNITS_PER_SEC/1000)
82		printf(" %.1fms", tmp / (TIME_UNITS_PER_SEC / 1000));
83	else
84		printf(" %uus", time);
85}
86
87static void RATEEST_parse(struct xt_option_call *cb)
88{
89	struct rateest_tg_udata *udata = cb->udata;
90
91	xtables_option_parse(cb);
92	switch (cb->entry->id) {
93	case O_INTERVAL:
94		if (RATEEST_get_time(&udata->interval, cb->arg) < 0)
95			xtables_error(PARAMETER_PROBLEM,
96				   "RATEEST: bad interval value \"%s\"",
97				   cb->arg);
98		break;
99	case O_EWMALOG:
100		if (RATEEST_get_time(&udata->ewma_log, cb->arg) < 0)
101			xtables_error(PARAMETER_PROBLEM,
102				   "RATEEST: bad ewmalog value \"%s\"",
103				   cb->arg);
104		break;
105	}
106}
107
108static void RATEEST_final_check(struct xt_fcheck_call *cb)
109{
110	struct xt_rateest_target_info *info = cb->data;
111	struct rateest_tg_udata *udata = cb->udata;
112
113	for (info->interval = 0; info->interval <= 5; info->interval++) {
114		if (udata->interval <= (1 << info->interval) * (TIME_UNITS_PER_SEC / 4))
115			break;
116	}
117
118	if (info->interval > 5)
119		xtables_error(PARAMETER_PROBLEM,
120			   "RATEEST: interval value is too large");
121	info->interval -= 2;
122
123	for (info->ewma_log = 1; info->ewma_log < 32; info->ewma_log++) {
124		double w = 1.0 - 1.0 / (1 << info->ewma_log);
125		if (udata->interval / (-log(w)) > udata->ewma_log)
126			break;
127	}
128	info->ewma_log--;
129
130	if (info->ewma_log == 0 || info->ewma_log >= 31)
131		xtables_error(PARAMETER_PROBLEM,
132			   "RATEEST: ewmalog value is out of range");
133}
134
135static void
136__RATEEST_print(const struct xt_entry_target *target, const char *prefix)
137{
138	const struct xt_rateest_target_info *info = (const void *)target->data;
139	unsigned int local_interval;
140	unsigned int local_ewma_log;
141
142	local_interval = (TIME_UNITS_PER_SEC << (info->interval + 2)) / 4;
143	local_ewma_log = local_interval * (1 << (info->ewma_log));
144
145	printf(" %sname %s", prefix, info->name);
146	printf(" %sinterval", prefix);
147	RATEEST_print_time(local_interval);
148	printf(" %sewmalog", prefix);
149	RATEEST_print_time(local_ewma_log);
150}
151
152static void
153RATEEST_print(const void *ip, const struct xt_entry_target *target,
154	      int numeric)
155{
156	__RATEEST_print(target, "");
157}
158
159static void
160RATEEST_save(const void *ip, const struct xt_entry_target *target)
161{
162	__RATEEST_print(target, "--rateest-");
163}
164
165static struct xtables_target rateest_tg_reg = {
166	.family		= NFPROTO_UNSPEC,
167	.name		= "RATEEST",
168	.version	= XTABLES_VERSION,
169	.size		= XT_ALIGN(sizeof(struct xt_rateest_target_info)),
170	.userspacesize	= offsetof(struct xt_rateest_target_info, est),
171	.help		= RATEEST_help,
172	.x6_parse	= RATEEST_parse,
173	.x6_fcheck	= RATEEST_final_check,
174	.print		= RATEEST_print,
175	.save		= RATEEST_save,
176	.x6_options	= RATEEST_opts,
177	.udata_size	= sizeof(struct rateest_tg_udata),
178};
179
180void _init(void)
181{
182	xtables_register_target(&rateest_tg_reg);
183}
184