libipt_LOG.c revision 127647892c7cac85baf8da62ed21232baa60f1c9 
1/* Shared library add-on to iptables to add LOG support. */
2#include <stdio.h>
3#include <netdb.h>
4#include <string.h>
5#include <stdlib.h>
6#include <syslog.h>
7#include <getopt.h>
8#include <xtables.h>
9#include <linux/netfilter_ipv4/ipt_LOG.h>
10
11#define LOG_DEFAULT_LEVEL LOG_WARNING
12
13#ifndef IPT_LOG_UID /* Old kernel */
14#define IPT_LOG_UID	0x08	/* Log UID owning local socket */
15#undef  IPT_LOG_MASK
16#define IPT_LOG_MASK	0x0f
17#endif
18
19static void LOG_help(void)
20{
21	printf(
22"LOG target options:\n"
23" --log-level level		Level of logging (numeric or see syslog.conf)\n"
24" --log-prefix prefix		Prefix log messages with this prefix.\n\n"
25" --log-tcp-sequence		Log TCP sequence numbers.\n\n"
26" --log-tcp-options		Log TCP options.\n\n"
27" --log-ip-options		Log IP options.\n\n"
28" --log-uid			Log UID owning the local socket.\n\n"
29" --log-macdecode		Decode MAC addresses and protocol.\n\n");
30}
31
32static const struct option LOG_opts[] = {
33	{ .name = "log-level",        .has_arg = 1, .val = '!' },
34	{ .name = "log-prefix",       .has_arg = 1, .val = '#' },
35	{ .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
36	{ .name = "log-tcp-options",  .has_arg = 0, .val = '2' },
37	{ .name = "log-ip-options",   .has_arg = 0, .val = '3' },
38	{ .name = "log-uid",          .has_arg = 0, .val = '4' },
39	{ .name = "log-macdecode",    .has_arg = 0, .val = '5' },
40	{ .name = NULL }
41};
42
43static void LOG_init(struct xt_entry_target *t)
44{
45	struct ipt_log_info *loginfo = (struct ipt_log_info *)t->data;
46
47	loginfo->level = LOG_DEFAULT_LEVEL;
48
49}
50
51struct ipt_log_names {
52	const char *name;
53	unsigned int level;
54};
55
56static const struct ipt_log_names ipt_log_names[]
57= { { .name = "alert",   .level = LOG_ALERT },
58    { .name = "crit",    .level = LOG_CRIT },
59    { .name = "debug",   .level = LOG_DEBUG },
60    { .name = "emerg",   .level = LOG_EMERG },
61    { .name = "error",   .level = LOG_ERR },		/* DEPRECATED */
62    { .name = "info",    .level = LOG_INFO },
63    { .name = "notice",  .level = LOG_NOTICE },
64    { .name = "panic",   .level = LOG_EMERG },		/* DEPRECATED */
65    { .name = "warning", .level = LOG_WARNING }
66};
67
68static u_int8_t
69parse_level(const char *level)
70{
71	unsigned int lev = -1;
72	unsigned int set = 0;
73
74	if (!xtables_strtoui(level, NULL, &lev, 0, 7)) {
75		unsigned int i = 0;
76
77		for (i = 0; i < ARRAY_SIZE(ipt_log_names); ++i)
78			if (strncasecmp(level, ipt_log_names[i].name,
79					strlen(level)) == 0) {
80				if (set++)
81					xtables_error(PARAMETER_PROBLEM,
82						   "log-level `%s' ambiguous",
83						   level);
84				lev = ipt_log_names[i].level;
85			}
86
87		if (!set)
88			xtables_error(PARAMETER_PROBLEM,
89				   "log-level `%s' unknown", level);
90	}
91
92	return lev;
93}
94
95#define IPT_LOG_OPT_LEVEL 0x01
96#define IPT_LOG_OPT_PREFIX 0x02
97#define IPT_LOG_OPT_TCPSEQ 0x04
98#define IPT_LOG_OPT_TCPOPT 0x08
99#define IPT_LOG_OPT_IPOPT 0x10
100#define IPT_LOG_OPT_UID 0x20
101#define IPT_LOG_OPT_MACDECODE 0x40
102
103static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
104                     const void *entry, struct xt_entry_target **target)
105{
106	struct ipt_log_info *loginfo = (struct ipt_log_info *)(*target)->data;
107
108	switch (c) {
109	case '!':
110		if (*flags & IPT_LOG_OPT_LEVEL)
111			xtables_error(PARAMETER_PROBLEM,
112				   "Can't specify --log-level twice");
113
114		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
115			xtables_error(PARAMETER_PROBLEM,
116				   "Unexpected `!' after --log-level");
117
118		loginfo->level = parse_level(optarg);
119		*flags |= IPT_LOG_OPT_LEVEL;
120		break;
121
122	case '#':
123		if (*flags & IPT_LOG_OPT_PREFIX)
124			xtables_error(PARAMETER_PROBLEM,
125				   "Can't specify --log-prefix twice");
126
127		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
128			xtables_error(PARAMETER_PROBLEM,
129				   "Unexpected `!' after --log-prefix");
130
131		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
132			xtables_error(PARAMETER_PROBLEM,
133				   "Maximum prefix length %u for --log-prefix",
134				   (unsigned int)sizeof(loginfo->prefix) - 1);
135
136		if (strlen(optarg) == 0)
137			xtables_error(PARAMETER_PROBLEM,
138				   "No prefix specified for --log-prefix");
139
140		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
141			xtables_error(PARAMETER_PROBLEM,
142				   "Newlines not allowed in --log-prefix");
143
144		strcpy(loginfo->prefix, optarg);
145		*flags |= IPT_LOG_OPT_PREFIX;
146		break;
147
148	case '1':
149		if (*flags & IPT_LOG_OPT_TCPSEQ)
150			xtables_error(PARAMETER_PROBLEM,
151				   "Can't specify --log-tcp-sequence "
152				   "twice");
153
154		loginfo->logflags |= IPT_LOG_TCPSEQ;
155		*flags |= IPT_LOG_OPT_TCPSEQ;
156		break;
157
158	case '2':
159		if (*flags & IPT_LOG_OPT_TCPOPT)
160			xtables_error(PARAMETER_PROBLEM,
161				   "Can't specify --log-tcp-options twice");
162
163		loginfo->logflags |= IPT_LOG_TCPOPT;
164		*flags |= IPT_LOG_OPT_TCPOPT;
165		break;
166
167	case '3':
168		if (*flags & IPT_LOG_OPT_IPOPT)
169			xtables_error(PARAMETER_PROBLEM,
170				   "Can't specify --log-ip-options twice");
171
172		loginfo->logflags |= IPT_LOG_IPOPT;
173		*flags |= IPT_LOG_OPT_IPOPT;
174		break;
175
176	case '4':
177		if (*flags & IPT_LOG_OPT_UID)
178			xtables_error(PARAMETER_PROBLEM,
179				   "Can't specify --log-uid twice");
180
181		loginfo->logflags |= IPT_LOG_UID;
182		*flags |= IPT_LOG_OPT_UID;
183		break;
184
185	case '5':
186		if (*flags & IPT_LOG_OPT_MACDECODE)
187			xtables_error(PARAMETER_PROBLEM,
188				      "Can't specifiy --log-macdecode twice");
189
190		loginfo->logflags |= IPT_LOG_MACDECODE;
191		*flags |= IPT_LOG_OPT_MACDECODE;
192		break;
193	default:
194		return 0;
195	}
196
197	return 1;
198}
199
200static void LOG_print(const void *ip, const struct xt_entry_target *target,
201                      int numeric)
202{
203	const struct ipt_log_info *loginfo
204		= (const struct ipt_log_info *)target->data;
205	unsigned int i = 0;
206
207	printf("LOG ");
208	if (numeric)
209		printf("flags %u level %u ",
210		       loginfo->logflags, loginfo->level);
211	else {
212		for (i = 0; i < ARRAY_SIZE(ipt_log_names); ++i)
213			if (loginfo->level == ipt_log_names[i].level) {
214				printf("level %s ", ipt_log_names[i].name);
215				break;
216			}
217		if (i == ARRAY_SIZE(ipt_log_names))
218			printf("UNKNOWN level %u ", loginfo->level);
219		if (loginfo->logflags & IPT_LOG_TCPSEQ)
220			printf("tcp-sequence ");
221		if (loginfo->logflags & IPT_LOG_TCPOPT)
222			printf("tcp-options ");
223		if (loginfo->logflags & IPT_LOG_IPOPT)
224			printf("ip-options ");
225		if (loginfo->logflags & IPT_LOG_UID)
226			printf("uid ");
227		if (loginfo->logflags & IPT_LOG_MACDECODE)
228			printf("macdecode ");
229		if (loginfo->logflags & ~(IPT_LOG_MASK))
230			printf("unknown-flags ");
231	}
232
233	if (strcmp(loginfo->prefix, "") != 0)
234		printf("prefix `%s' ", loginfo->prefix);
235}
236
237static void LOG_save(const void *ip, const struct xt_entry_target *target)
238{
239	const struct ipt_log_info *loginfo
240		= (const struct ipt_log_info *)target->data;
241
242	if (strcmp(loginfo->prefix, "") != 0) {
243		printf("--log-prefix ");
244		xtables_save_string(loginfo->prefix);
245	}
246
247	if (loginfo->level != LOG_DEFAULT_LEVEL)
248		printf("--log-level %d ", loginfo->level);
249
250	if (loginfo->logflags & IPT_LOG_TCPSEQ)
251		printf("--log-tcp-sequence ");
252	if (loginfo->logflags & IPT_LOG_TCPOPT)
253		printf("--log-tcp-options ");
254	if (loginfo->logflags & IPT_LOG_IPOPT)
255		printf("--log-ip-options ");
256	if (loginfo->logflags & IPT_LOG_UID)
257		printf("--log-uid ");
258	if (loginfo->logflags & IPT_LOG_MACDECODE)
259		printf("--log-macdecode ");
260}
261
262static struct xtables_target log_tg_reg = {
263    .name          = "LOG",
264    .version       = XTABLES_VERSION,
265    .family        = NFPROTO_IPV4,
266    .size          = XT_ALIGN(sizeof(struct ipt_log_info)),
267    .userspacesize = XT_ALIGN(sizeof(struct ipt_log_info)),
268    .help          = LOG_help,
269    .init          = LOG_init,
270    .parse         = LOG_parse,
271    .print         = LOG_print,
272    .save          = LOG_save,
273    .extra_opts    = LOG_opts,
274};
275
276void _init(void)
277{
278	xtables_register_target(&log_tg_reg);
279}
280