libxt_NFLOG.c revision e88a7c2c7175742b58b6aa03f2b5aba2d80330a1 
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->threshold	= XT_NFLOG_DEFAULT_THRESHOLD;
40}
41
42static int NFLOG_parse(int c, char **argv, int invert, unsigned int *flags,
43                       const void *entry, struct xt_entry_target **target)
44{
45	struct xt_nflog_info *info = (struct xt_nflog_info *)(*target)->data;
46	int n;
47	size_t length;
48
49	switch (c) {
50	case NFLOG_GROUP:
51		if (*flags & NFLOG_GROUP)
52			xtables_error(PARAMETER_PROBLEM,
53				   "Can't specify --nflog-group twice");
54		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
55			xtables_error(PARAMETER_PROBLEM,
56				   "Unexpected `!' after --nflog-group");
57
58		n = atoi(optarg);
59		if (n < 0)
60			xtables_error(PARAMETER_PROBLEM,
61				   "--nflog-group can not be negative");
62		info->group = n;
63		break;
64	case NFLOG_PREFIX:
65		if (*flags & NFLOG_PREFIX)
66			xtables_error(PARAMETER_PROBLEM,
67				   "Can't specify --nflog-prefix twice");
68		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
69			xtables_error(PARAMETER_PROBLEM,
70				   "Unexpected `!' after --nflog-prefix");
71
72		length = strlen(optarg);
73		if (length == 0)
74			xtables_error(PARAMETER_PROBLEM,
75				   "No prefix specified for --nflog-prefix");
76		if (length >= sizeof(info->prefix))
77			xtables_error(PARAMETER_PROBLEM,
78				   "--nflog-prefix too long, max %Zu characters",
79				   sizeof(info->prefix) - 1);
80		if (length != strlen(strtok(optarg, "\n")))
81			xtables_error(PARAMETER_PROBLEM,
82				   "Newlines are not allowed in --nflog-prefix");
83		strcpy(info->prefix, optarg);
84		break;
85	case NFLOG_RANGE:
86		if (*flags & NFLOG_RANGE)
87			xtables_error(PARAMETER_PROBLEM,
88				   "Can't specify --nflog-range twice");
89		n = atoi(optarg);
90		if (n < 0)
91			xtables_error(PARAMETER_PROBLEM,
92				   "Invalid --nflog-range, must be >= 0");
93		info->len = n;
94		break;
95	case NFLOG_THRESHOLD:
96		if (*flags & NFLOG_THRESHOLD)
97			xtables_error(PARAMETER_PROBLEM,
98				   "Can't specify --nflog-threshold twice");
99		n = atoi(optarg);
100		if (n < 1)
101			xtables_error(PARAMETER_PROBLEM,
102				   "Invalid --nflog-threshold, must be >= 1");
103		info->threshold = n;
104		break;
105	}
106	*flags |= c;
107	return 1;
108}
109
110static void nflog_print(const struct xt_nflog_info *info, char *prefix)
111{
112	if (info->prefix[0] != '\0') {
113		printf(" %snflog-prefix ", prefix);
114		xtables_save_string(info->prefix);
115	}
116	if (info->group)
117		printf(" %snflog-group %u", prefix, info->group);
118	if (info->len)
119		printf(" %snflog-range %u", prefix, info->len);
120	if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
121		printf(" %snflog-threshold %u", prefix, info->threshold);
122}
123
124static void NFLOG_print(const void *ip, const struct xt_entry_target *target,
125                        int numeric)
126{
127	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
128
129	nflog_print(info, "");
130}
131
132static void NFLOG_save(const void *ip, const struct xt_entry_target *target)
133{
134	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
135
136	nflog_print(info, "--");
137}
138
139static struct xtables_target nflog_target = {
140	.family		= NFPROTO_UNSPEC,
141	.name		= "NFLOG",
142	.version	= XTABLES_VERSION,
143	.size		= XT_ALIGN(sizeof(struct xt_nflog_info)),
144	.userspacesize	= XT_ALIGN(sizeof(struct xt_nflog_info)),
145	.help		= NFLOG_help,
146	.init		= NFLOG_init,
147	.parse		= NFLOG_parse,
148	.print		= NFLOG_print,
149	.save		= NFLOG_save,
150	.extra_opts	= NFLOG_opts,
151};
152
153void _init(void)
154{
155	xtables_register_target(&nflog_target);
156}
157