libxt_NFLOG.c revision 32b8e61e4e5bd405d9ad07bf9468498dfbb19f9e 
1#include <stdbool.h>
2#include <stdlib.h>
3#include <stdio.h>
4#include <string.h>
5#include <getopt.h>
6#include <xtables.h>
7
8#include <linux/netfilter/x_tables.h>
9#include <linux/netfilter/xt_NFLOG.h>
10
11enum {
12	NFLOG_GROUP	= 0x1,
13	NFLOG_PREFIX	= 0x2,
14	NFLOG_RANGE	= 0x4,
15	NFLOG_THRESHOLD	= 0x8,
16};
17
18static const struct option NFLOG_opts[] = {
19	{.name = "nflog-group",     .has_arg = true, .val = NFLOG_GROUP},
20	{.name = "nflog-prefix",    .has_arg = true, .val = NFLOG_PREFIX},
21	{.name = "nflog-range",     .has_arg = true, .val = NFLOG_RANGE},
22	{.name = "nflog-threshold", .has_arg = true, .val = NFLOG_THRESHOLD},
23	XT_GETOPT_TABLEEND,
24};
25
26static void NFLOG_help(void)
27{
28	printf("NFLOG target options:\n"
29	       " --nflog-group NUM		NETLINK group used for logging\n"
30	       " --nflog-range NUM		Number of byte to copy\n"
31	       " --nflog-threshold NUM		Message threshold of in-kernel queue\n"
32	       " --nflog-prefix STRING		Prefix string for log messages\n");
33}
34
35static void NFLOG_init(struct xt_entry_target *t)
36{
37	struct xt_nflog_info *info = (struct xt_nflog_info *)t->data;
38
39	info->group	= 0;
40	info->threshold	= XT_NFLOG_DEFAULT_THRESHOLD;
41}
42
43static int NFLOG_parse(int c, char **argv, int invert, unsigned int *flags,
44                       const void *entry, struct xt_entry_target **target)
45{
46	struct xt_nflog_info *info = (struct xt_nflog_info *)(*target)->data;
47	int n;
48	size_t length;
49
50	switch (c) {
51	case NFLOG_GROUP:
52		if (*flags & NFLOG_GROUP)
53			xtables_error(PARAMETER_PROBLEM,
54				   "Can't specify --nflog-group twice");
55		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
56			xtables_error(PARAMETER_PROBLEM,
57				   "Unexpected `!' after --nflog-group");
58
59		n = atoi(optarg);
60		if (n < 0)
61			xtables_error(PARAMETER_PROBLEM,
62				   "--nflog-group can not be negative");
63		info->group = n;
64		break;
65	case NFLOG_PREFIX:
66		if (*flags & NFLOG_PREFIX)
67			xtables_error(PARAMETER_PROBLEM,
68				   "Can't specify --nflog-prefix twice");
69		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
70			xtables_error(PARAMETER_PROBLEM,
71				   "Unexpected `!' after --nflog-prefix");
72
73		length = strlen(optarg);
74		if (length == 0)
75			xtables_error(PARAMETER_PROBLEM,
76				   "No prefix specified for --nflog-prefix");
77		if (length >= sizeof(info->prefix))
78			xtables_error(PARAMETER_PROBLEM,
79				   "--nflog-prefix too long, max %Zu characters",
80				   sizeof(info->prefix) - 1);
81		if (length != strlen(strtok(optarg, "\n")))
82			xtables_error(PARAMETER_PROBLEM,
83				   "Newlines are not allowed in --nflog-prefix");
84		strcpy(info->prefix, optarg);
85		break;
86	case NFLOG_RANGE:
87		if (*flags & NFLOG_RANGE)
88			xtables_error(PARAMETER_PROBLEM,
89				   "Can't specify --nflog-range twice");
90		n = atoi(optarg);
91		if (n < 0)
92			xtables_error(PARAMETER_PROBLEM,
93				   "Invalid --nflog-range, must be >= 0");
94		info->len = n;
95		break;
96	case NFLOG_THRESHOLD:
97		if (*flags & NFLOG_THRESHOLD)
98			xtables_error(PARAMETER_PROBLEM,
99				   "Can't specify --nflog-threshold twice");
100		n = atoi(optarg);
101		if (n < 1)
102			xtables_error(PARAMETER_PROBLEM,
103				   "Invalid --nflog-threshold, must be >= 1");
104		info->threshold = n;
105		break;
106	default:
107		return 0;
108	}
109	*flags |= c;
110	return 1;
111}
112
113static void nflog_print(const struct xt_nflog_info *info, char *prefix)
114{
115	if (info->prefix[0] != '\0') {
116		printf("%snflog-prefix ", prefix);
117		xtables_save_string(info->prefix);
118	}
119	if (info->group)
120		printf("%snflog-group %u ", prefix, info->group);
121	if (info->len)
122		printf("%snflog-range %u ", prefix, info->len);
123	if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
124		printf("%snflog-threshold %u ", prefix, info->threshold);
125}
126
127static void NFLOG_print(const void *ip, const struct xt_entry_target *target,
128                        int numeric)
129{
130	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
131
132	nflog_print(info, "");
133}
134
135static void NFLOG_save(const void *ip, const struct xt_entry_target *target)
136{
137	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
138
139	nflog_print(info, "--");
140}
141
142static struct xtables_target nflog_target = {
143	.family		= NFPROTO_UNSPEC,
144	.name		= "NFLOG",
145	.version	= XTABLES_VERSION,
146	.size		= XT_ALIGN(sizeof(struct xt_nflog_info)),
147	.userspacesize	= XT_ALIGN(sizeof(struct xt_nflog_info)),
148	.help		= NFLOG_help,
149	.init		= NFLOG_init,
150	.parse		= NFLOG_parse,
151	.print		= NFLOG_print,
152	.save		= NFLOG_save,
153	.extra_opts	= NFLOG_opts,
154};
155
156void _init(void)
157{
158	xtables_register_target(&nflog_target);
159}
160