libxt_RATEEST.c revision 68818f746bf9c68de04a75fbe756bf2c73e0fb32 
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
10/* hack to pass raw values to final_check */
11static unsigned int interval;
12static unsigned int ewma_log;
13
14static void
15RATEEST_help(void)
16{
17	printf(
18"RATEEST target options:\n"
19"  --rateest-name name		Rate estimator name\n"
20"  --rateest-interval sec	Rate measurement interval in seconds\n"
21"  --rateest-ewmalog value	Rate measurement averaging time constant\n");
22}
23
24enum {
25	O_NAME = 0,
26	O_INTERVAL,
27	O_EWMALOG,
28};
29
30#define s struct xt_rateest_target_info
31static const struct xt_option_entry RATEEST_opts[] = {
32	{.name = "rateest-name", .id = O_NAME, .type = XTTYPE_STRING,
33	 .flags = XTOPT_MAND | XTOPT_PUT, XTOPT_POINTER(s, name)},
34	{.name = "rateest-interval", .id = O_INTERVAL, .type = XTTYPE_STRING,
35	 .flags = XTOPT_MAND},
36	{.name = "rateest-ewmalog", .id = O_EWMALOG, .type = XTTYPE_STRING,
37	 .flags = XTOPT_MAND},
38	XTOPT_TABLEEND,
39};
40#undef s
41
42/* Copied from iproute */
43#define TIME_UNITS_PER_SEC	1000000
44
45static int
46RATEEST_get_time(unsigned int *time, const char *str)
47{
48	double t;
49	char *p;
50
51	t = strtod(str, &p);
52	if (p == str)
53		return -1;
54
55	if (*p) {
56		if (strcasecmp(p, "s") == 0 || strcasecmp(p, "sec")==0 ||
57		    strcasecmp(p, "secs")==0)
58			t *= TIME_UNITS_PER_SEC;
59		else if (strcasecmp(p, "ms") == 0 || strcasecmp(p, "msec")==0 ||
60			 strcasecmp(p, "msecs") == 0)
61			t *= TIME_UNITS_PER_SEC/1000;
62		else if (strcasecmp(p, "us") == 0 || strcasecmp(p, "usec")==0 ||
63			 strcasecmp(p, "usecs") == 0)
64			t *= TIME_UNITS_PER_SEC/1000000;
65		else
66			return -1;
67	}
68
69	*time = t;
70	return 0;
71}
72
73static void
74RATEEST_print_time(unsigned int time)
75{
76	double tmp = time;
77
78	if (tmp >= TIME_UNITS_PER_SEC)
79		printf(" %.1fs", tmp / TIME_UNITS_PER_SEC);
80	else if (tmp >= TIME_UNITS_PER_SEC/1000)
81		printf(" %.1fms", tmp / (TIME_UNITS_PER_SEC / 1000));
82	else
83		printf(" %uus", time);
84}
85
86static void RATEEST_parse(struct xt_option_call *cb)
87{
88	xtables_option_parse(cb);
89	switch (cb->entry->id) {
90	case O_INTERVAL:
91		if (RATEEST_get_time(&interval, cb->arg) < 0)
92			xtables_error(PARAMETER_PROBLEM,
93				   "RATEEST: bad interval value \"%s\"",
94				   cb->arg);
95		break;
96	case O_EWMALOG:
97		if (RATEEST_get_time(&ewma_log, cb->arg) < 0)
98			xtables_error(PARAMETER_PROBLEM,
99				   "RATEEST: bad ewmalog value \"%s\"",
100				   cb->arg);
101		break;
102	}
103}
104
105static void RATEEST_final_check(struct xt_fcheck_call *cb)
106{
107	struct xt_rateest_target_info *info = cb->data;
108
109	for (info->interval = 0; info->interval <= 5; info->interval++) {
110		if (interval <= (1 << info->interval) * (TIME_UNITS_PER_SEC / 4))
111			break;
112	}
113
114	if (info->interval > 5)
115		xtables_error(PARAMETER_PROBLEM,
116			   "RATEEST: interval value is too large");
117	info->interval -= 2;
118
119	for (info->ewma_log = 1; info->ewma_log < 32; info->ewma_log++) {
120		double w = 1.0 - 1.0 / (1 << info->ewma_log);
121		if (interval / (-log(w)) > ewma_log)
122			break;
123	}
124	info->ewma_log--;
125
126	if (info->ewma_log == 0 || info->ewma_log >= 31)
127		xtables_error(PARAMETER_PROBLEM,
128			   "RATEEST: ewmalog value is out of range");
129}
130
131static void
132__RATEEST_print(const struct xt_entry_target *target, const char *prefix)
133{
134	const struct xt_rateest_target_info *info = (const void *)target->data;
135	unsigned int local_interval;
136	unsigned int local_ewma_log;
137
138	local_interval = (TIME_UNITS_PER_SEC << (info->interval + 2)) / 4;
139	local_ewma_log = local_interval * (1 << (info->ewma_log));
140
141	printf(" %sname %s", prefix, info->name);
142	printf(" %sinterval", prefix);
143	RATEEST_print_time(local_interval);
144	printf(" %sewmalog", prefix);
145	RATEEST_print_time(local_ewma_log);
146}
147
148static void
149RATEEST_print(const void *ip, const struct xt_entry_target *target,
150	      int numeric)
151{
152	__RATEEST_print(target, "");
153}
154
155static void
156RATEEST_save(const void *ip, const struct xt_entry_target *target)
157{
158	__RATEEST_print(target, "--rateest-");
159}
160
161static struct xtables_target rateest_tg_reg = {
162	.family		= NFPROTO_UNSPEC,
163	.name		= "RATEEST",
164	.version	= XTABLES_VERSION,
165	.size		= XT_ALIGN(sizeof(struct xt_rateest_target_info)),
166	.userspacesize	= XT_ALIGN(sizeof(struct xt_rateest_target_info)),
167	.help		= RATEEST_help,
168	.x6_parse	= RATEEST_parse,
169	.x6_fcheck	= RATEEST_final_check,
170	.print		= RATEEST_print,
171	.save		= RATEEST_save,
172	.x6_options	= RATEEST_opts,
173};
174
175void _init(void)
176{
177	xtables_register_target(&rateest_tg_reg);
178}
179