libxt_NFLOG.c revision 7070b1f3c88a0c3d4e315c00cca61f05b0fbc882 
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	O_GROUP = 0,
13	O_PREFIX,
14	O_RANGE,
15	O_SIZE,
16	O_THRESHOLD,
17	F_RANGE = 1 << O_RANGE,
18	F_SIZE = 1 << O_SIZE,
19};
20
21#define s struct xt_nflog_info
22static const struct xt_option_entry NFLOG_opts[] = {
23	{.name = "nflog-group", .id = O_GROUP, .type = XTTYPE_UINT16,
24	 .flags = XTOPT_PUT, XTOPT_POINTER(s, group)},
25	{.name = "nflog-prefix", .id = O_PREFIX, .type = XTTYPE_STRING,
26	 .min = 1, .flags = XTOPT_PUT, XTOPT_POINTER(s, prefix)},
27	{.name = "nflog-range", .id = O_RANGE, .type = XTTYPE_UINT32,
28	 .excl = F_SIZE, .flags = XTOPT_PUT, XTOPT_POINTER(s, len)},
29	{.name = "nflog-size", .id = O_SIZE, .type = XTTYPE_UINT32,
30	 .excl = F_RANGE, .flags = XTOPT_PUT, XTOPT_POINTER(s, len)},
31	{.name = "nflog-threshold", .id = O_THRESHOLD, .type = XTTYPE_UINT16,
32	 .flags = XTOPT_PUT, XTOPT_POINTER(s, threshold)},
33	XTOPT_TABLEEND,
34};
35#undef s
36
37static void NFLOG_help(void)
38{
39	printf("NFLOG target options:\n"
40	       " --nflog-group NUM		NETLINK group used for logging\n"
41	       " --nflog-range NUM		This option has no effect, use --nflog-size\n"
42	       " --nflog-size NUM		Number of bytes to copy\n"
43	       " --nflog-threshold NUM		Message threshold of in-kernel queue\n"
44	       " --nflog-prefix STRING		Prefix string for log messages\n");
45}
46
47static void NFLOG_init(struct xt_entry_target *t)
48{
49	struct xt_nflog_info *info = (struct xt_nflog_info *)t->data;
50
51	info->threshold	= XT_NFLOG_DEFAULT_THRESHOLD;
52}
53
54static void NFLOG_parse(struct xt_option_call *cb)
55{
56	xtables_option_parse(cb);
57	switch (cb->entry->id) {
58	case O_PREFIX:
59		if (strchr(cb->arg, '\n') != NULL)
60			xtables_error(PARAMETER_PROBLEM,
61				   "Newlines not allowed in --log-prefix");
62		break;
63	}
64}
65
66static void NFLOG_check(struct xt_fcheck_call *cb)
67{
68	struct xt_nflog_info *info = cb->data;
69
70	if (cb->xflags & F_RANGE)
71		fprintf(stderr, "warn: --nflog-range has never worked and is no"
72			" longer supported, please use --nflog-size insted\n");
73
74	if (cb->xflags & F_SIZE)
75		info->flags |= XT_NFLOG_F_COPY_LEN;
76}
77
78static void nflog_print(const struct xt_nflog_info *info, char *prefix)
79{
80	if (info->prefix[0] != '\0') {
81		printf(" %snflog-prefix ", prefix);
82		xtables_save_string(info->prefix);
83	}
84	if (info->group)
85		printf(" %snflog-group %u", prefix, info->group);
86	if (info->len && info->flags & XT_NFLOG_F_COPY_LEN)
87		printf(" %snflog-size %u", prefix, info->len);
88	else if (info->len)
89		printf(" %snflog-range %u", prefix, info->len);
90	if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
91		printf(" %snflog-threshold %u", prefix, info->threshold);
92}
93
94static void NFLOG_print(const void *ip, const struct xt_entry_target *target,
95			int numeric)
96{
97	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
98
99	nflog_print(info, "");
100}
101
102static void NFLOG_save(const void *ip, const struct xt_entry_target *target)
103{
104	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
105
106	nflog_print(info, "--");
107}
108
109static void nflog_print_xlate(const struct xt_nflog_info *info,
110			      struct xt_xlate *xl)
111{
112	xt_xlate_add(xl, "log ");
113	if (info->prefix[0] != '\0')
114		xt_xlate_add(xl, "prefix \\\"%s\\\" ", info->prefix);
115	if (info->len)
116		xt_xlate_add(xl, "snaplen %u ", info->len);
117	if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
118		xt_xlate_add(xl, "queue-threshold %u ", info->threshold);
119	xt_xlate_add(xl, "group %u ", info->group);
120}
121
122static int NFLOG_xlate(const void *ip, const struct xt_entry_target *target,
123		       struct xt_xlate *xl, int numeric)
124{
125	const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
126
127	nflog_print_xlate(info, xl);
128
129	return 1;
130}
131
132static struct xtables_target nflog_target = {
133	.family		= NFPROTO_UNSPEC,
134	.name		= "NFLOG",
135	.version	= XTABLES_VERSION,
136	.size		= XT_ALIGN(sizeof(struct xt_nflog_info)),
137	.userspacesize	= XT_ALIGN(sizeof(struct xt_nflog_info)),
138	.help		= NFLOG_help,
139	.init		= NFLOG_init,
140	.x6_fcheck	= NFLOG_check,
141	.x6_parse	= NFLOG_parse,
142	.print		= NFLOG_print,
143	.save		= NFLOG_save,
144	.x6_options	= NFLOG_opts,
145	.xlate		= NFLOG_xlate,
146};
147
148void _init(void)
149{
150	xtables_register_target(&nflog_target);
151}
152