libip6t_LOG.c revision 127647892c7cac85baf8da62ed21232baa60f1c9 
1/* Shared library add-on to ip6tables 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_ipv6/ip6t_LOG.h>
10
11#ifndef IP6T_LOG_UID	/* Old kernel */
12#define IP6T_LOG_UID	0x08
13#undef  IP6T_LOG_MASK
14#define IP6T_LOG_MASK	0x0f
15#endif
16
17#define LOG_DEFAULT_LEVEL LOG_WARNING
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"
25" --log-tcp-sequence		Log TCP sequence numbers.\n"
26" --log-tcp-options		Log TCP options.\n"
27" --log-ip-options		Log IP options.\n"
28" --log-uid			Log UID owning the local socket.\n"
29" --log-macdecode		Decode MAC addresses and protocol.\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 ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
46
47	loginfo->level = LOG_DEFAULT_LEVEL;
48
49}
50
51struct ip6t_log_names {
52	const char *name;
53	unsigned int level;
54};
55
56static const struct ip6t_log_names ip6t_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(ip6t_log_names); ++i)
78			if (strncasecmp(level, ip6t_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 = ip6t_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 IP6T_LOG_OPT_LEVEL 0x01
96#define IP6T_LOG_OPT_PREFIX 0x02
97#define IP6T_LOG_OPT_TCPSEQ 0x04
98#define IP6T_LOG_OPT_TCPOPT 0x08
99#define IP6T_LOG_OPT_IPOPT 0x10
100#define IP6T_LOG_OPT_UID 0x20
101#define IP6T_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 ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
107
108	switch (c) {
109	case '!':
110		if (*flags & IP6T_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 |= IP6T_LOG_OPT_LEVEL;
120		break;
121
122	case '#':
123		if (*flags & IP6T_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 |= IP6T_LOG_OPT_PREFIX;
146		break;
147
148	case '1':
149		if (*flags & IP6T_LOG_OPT_TCPSEQ)
150			xtables_error(PARAMETER_PROBLEM,
151				   "Can't specify --log-tcp-sequence "
152				   "twice");
153
154		loginfo->logflags |= IP6T_LOG_TCPSEQ;
155		*flags |= IP6T_LOG_OPT_TCPSEQ;
156		break;
157
158	case '2':
159		if (*flags & IP6T_LOG_OPT_TCPOPT)
160			xtables_error(PARAMETER_PROBLEM,
161				   "Can't specify --log-tcp-options twice");
162
163		loginfo->logflags |= IP6T_LOG_TCPOPT;
164		*flags |= IP6T_LOG_OPT_TCPOPT;
165		break;
166
167	case '3':
168		if (*flags & IP6T_LOG_OPT_IPOPT)
169			xtables_error(PARAMETER_PROBLEM,
170				   "Can't specify --log-ip-options twice");
171
172		loginfo->logflags |= IP6T_LOG_IPOPT;
173		*flags |= IP6T_LOG_OPT_IPOPT;
174		break;
175
176	case '4':
177		if (*flags & IP6T_LOG_OPT_UID)
178			xtables_error(PARAMETER_PROBLEM,
179				   "Can't specify --log-uid twice");
180
181		loginfo->logflags |= IP6T_LOG_UID;
182		*flags |= IP6T_LOG_OPT_UID;
183		break;
184
185	case '5':
186		if (*flags & IP6T_LOG_OPT_MACDECODE)
187			xtables_error(PARAMETER_PROBLEM,
188				      "Can't specify --log-macdecode twice");
189
190		loginfo->logflags |= IP6T_LOG_MACDECODE;
191		*flags |= IP6T_LOG_OPT_MACDECODE;
192		break;
193
194	default:
195		return 0;
196	}
197
198	return 1;
199}
200
201static void LOG_print(const void *ip, const struct xt_entry_target *target,
202                      int numeric)
203{
204	const struct ip6t_log_info *loginfo
205		= (const struct ip6t_log_info *)target->data;
206	unsigned int i = 0;
207
208	printf("LOG ");
209	if (numeric)
210		printf("flags %u level %u ",
211		       loginfo->logflags, loginfo->level);
212	else {
213		for (i = 0; i < ARRAY_SIZE(ip6t_log_names); ++i)
214			if (loginfo->level == ip6t_log_names[i].level) {
215				printf("level %s ", ip6t_log_names[i].name);
216				break;
217			}
218		if (i == ARRAY_SIZE(ip6t_log_names))
219			printf("UNKNOWN level %u ", loginfo->level);
220		if (loginfo->logflags & IP6T_LOG_TCPSEQ)
221			printf("tcp-sequence ");
222		if (loginfo->logflags & IP6T_LOG_TCPOPT)
223			printf("tcp-options ");
224		if (loginfo->logflags & IP6T_LOG_IPOPT)
225			printf("ip-options ");
226		if (loginfo->logflags & IP6T_LOG_UID)
227			printf("uid ");
228		if (loginfo->logflags & IP6T_LOG_MACDECODE)
229			printf("macdecode ");
230		if (loginfo->logflags & ~(IP6T_LOG_MASK))
231			printf("unknown-flags ");
232	}
233
234	if (strcmp(loginfo->prefix, "") != 0)
235		printf("prefix `%s' ", loginfo->prefix);
236}
237
238static void LOG_save(const void *ip, const struct xt_entry_target *target)
239{
240	const struct ip6t_log_info *loginfo
241		= (const struct ip6t_log_info *)target->data;
242
243	if (strcmp(loginfo->prefix, "") != 0)
244		printf("--log-prefix \"%s\" ", loginfo->prefix);
245
246	if (loginfo->level != LOG_DEFAULT_LEVEL)
247		printf("--log-level %d ", loginfo->level);
248
249	if (loginfo->logflags & IP6T_LOG_TCPSEQ)
250		printf("--log-tcp-sequence ");
251	if (loginfo->logflags & IP6T_LOG_TCPOPT)
252		printf("--log-tcp-options ");
253	if (loginfo->logflags & IP6T_LOG_IPOPT)
254		printf("--log-ip-options ");
255	if (loginfo->logflags & IP6T_LOG_UID)
256		printf("--log-uid ");
257	if (loginfo->logflags & IP6T_LOG_MACDECODE)
258		printf("--log-macdecode ");
259}
260
261static struct xtables_target log_tg6_reg = {
262    .name          = "LOG",
263    .version       = XTABLES_VERSION,
264    .family        = NFPROTO_IPV6,
265    .size          = XT_ALIGN(sizeof(struct ip6t_log_info)),
266    .userspacesize = XT_ALIGN(sizeof(struct ip6t_log_info)),
267    .help          = LOG_help,
268    .init          = LOG_init,
269    .parse         = LOG_parse,
270    .print         = LOG_print,
271    .save          = LOG_save,
272    .extra_opts    = LOG_opts,
273};
274
275void _init(void)
276{
277	xtables_register_target(&log_tg6_reg);
278}
279