libip6t_LOG.c revision 73866357e4a7a0fdc1b293bf8863fee2bd56da9e 
1/* Shared library add-on to ip6tables to add LOG support. */
2#include <stdbool.h>
3#include <stdio.h>
4#include <netdb.h>
5#include <string.h>
6#include <stdlib.h>
7#include <syslog.h>
8#include <getopt.h>
9#include <xtables.h>
10#include <linux/netfilter_ipv6/ip6t_LOG.h>
11
12#ifndef IP6T_LOG_UID	/* Old kernel */
13#define IP6T_LOG_UID	0x08
14#undef  IP6T_LOG_MASK
15#define IP6T_LOG_MASK	0x0f
16#endif
17
18#define LOG_DEFAULT_LEVEL LOG_WARNING
19
20static void LOG_help(void)
21{
22	printf(
23"LOG target options:\n"
24" --log-level level		Level of logging (numeric or see syslog.conf)\n"
25" --log-prefix prefix		Prefix log messages with this prefix.\n"
26" --log-tcp-sequence		Log TCP sequence numbers.\n"
27" --log-tcp-options		Log TCP options.\n"
28" --log-ip-options		Log IP options.\n"
29" --log-uid			Log UID owning the local socket.\n"
30" --log-macdecode		Decode MAC addresses and protocol.\n");
31}
32
33static const struct option LOG_opts[] = {
34	{.name = "log-level",        .has_arg = true,  .val = '!'},
35	{.name = "log-prefix",       .has_arg = true,  .val = '#'},
36	{.name = "log-tcp-sequence", .has_arg = false, .val = '1'},
37	{.name = "log-tcp-options",  .has_arg = false, .val = '2'},
38	{.name = "log-ip-options",   .has_arg = false, .val = '3'},
39	{.name = "log-uid",          .has_arg = false, .val = '4'},
40	{.name = "log-macdecode",    .has_arg = false, .val = '5'},
41	XT_GETOPT_TABLEEND,
42};
43
44static void LOG_init(struct xt_entry_target *t)
45{
46	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
47
48	loginfo->level = LOG_DEFAULT_LEVEL;
49
50}
51
52struct ip6t_log_names {
53	const char *name;
54	unsigned int level;
55};
56
57static const struct ip6t_log_names ip6t_log_names[]
58= { { .name = "alert",   .level = LOG_ALERT },
59    { .name = "crit",    .level = LOG_CRIT },
60    { .name = "debug",   .level = LOG_DEBUG },
61    { .name = "emerg",   .level = LOG_EMERG },
62    { .name = "error",   .level = LOG_ERR },		/* DEPRECATED */
63    { .name = "info",    .level = LOG_INFO },
64    { .name = "notice",  .level = LOG_NOTICE },
65    { .name = "panic",   .level = LOG_EMERG },		/* DEPRECATED */
66    { .name = "warning", .level = LOG_WARNING }
67};
68
69static uint8_t
70parse_level(const char *level)
71{
72	unsigned int lev = -1;
73	unsigned int set = 0;
74
75	if (!xtables_strtoui(level, NULL, &lev, 0, 7)) {
76		unsigned int i = 0;
77
78		for (i = 0; i < ARRAY_SIZE(ip6t_log_names); ++i)
79			if (strncasecmp(level, ip6t_log_names[i].name,
80					strlen(level)) == 0) {
81				if (set++)
82					xtables_error(PARAMETER_PROBLEM,
83						   "log-level `%s' ambiguous",
84						   level);
85				lev = ip6t_log_names[i].level;
86			}
87
88		if (!set)
89			xtables_error(PARAMETER_PROBLEM,
90				   "log-level `%s' unknown", level);
91	}
92
93	return lev;
94}
95
96#define IP6T_LOG_OPT_LEVEL 0x01
97#define IP6T_LOG_OPT_PREFIX 0x02
98#define IP6T_LOG_OPT_TCPSEQ 0x04
99#define IP6T_LOG_OPT_TCPOPT 0x08
100#define IP6T_LOG_OPT_IPOPT 0x10
101#define IP6T_LOG_OPT_UID 0x20
102#define IP6T_LOG_OPT_MACDECODE 0x40
103
104static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
105                     const void *entry, struct xt_entry_target **target)
106{
107	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
108
109	switch (c) {
110	case '!':
111		if (*flags & IP6T_LOG_OPT_LEVEL)
112			xtables_error(PARAMETER_PROBLEM,
113				   "Can't specify --log-level twice");
114
115		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
116			xtables_error(PARAMETER_PROBLEM,
117				   "Unexpected `!' after --log-level");
118
119		loginfo->level = parse_level(optarg);
120		*flags |= IP6T_LOG_OPT_LEVEL;
121		break;
122
123	case '#':
124		if (*flags & IP6T_LOG_OPT_PREFIX)
125			xtables_error(PARAMETER_PROBLEM,
126				   "Can't specify --log-prefix twice");
127
128		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
129			xtables_error(PARAMETER_PROBLEM,
130				   "Unexpected `!' after --log-prefix");
131
132		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
133			xtables_error(PARAMETER_PROBLEM,
134				   "Maximum prefix length %u for --log-prefix",
135				   (unsigned int)sizeof(loginfo->prefix) - 1);
136
137		if (strlen(optarg) == 0)
138			xtables_error(PARAMETER_PROBLEM,
139				   "No prefix specified for --log-prefix");
140
141		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
142			xtables_error(PARAMETER_PROBLEM,
143				   "Newlines not allowed in --log-prefix");
144
145		strcpy(loginfo->prefix, optarg);
146		*flags |= IP6T_LOG_OPT_PREFIX;
147		break;
148
149	case '1':
150		if (*flags & IP6T_LOG_OPT_TCPSEQ)
151			xtables_error(PARAMETER_PROBLEM,
152				   "Can't specify --log-tcp-sequence "
153				   "twice");
154
155		loginfo->logflags |= IP6T_LOG_TCPSEQ;
156		*flags |= IP6T_LOG_OPT_TCPSEQ;
157		break;
158
159	case '2':
160		if (*flags & IP6T_LOG_OPT_TCPOPT)
161			xtables_error(PARAMETER_PROBLEM,
162				   "Can't specify --log-tcp-options twice");
163
164		loginfo->logflags |= IP6T_LOG_TCPOPT;
165		*flags |= IP6T_LOG_OPT_TCPOPT;
166		break;
167
168	case '3':
169		if (*flags & IP6T_LOG_OPT_IPOPT)
170			xtables_error(PARAMETER_PROBLEM,
171				   "Can't specify --log-ip-options twice");
172
173		loginfo->logflags |= IP6T_LOG_IPOPT;
174		*flags |= IP6T_LOG_OPT_IPOPT;
175		break;
176
177	case '4':
178		if (*flags & IP6T_LOG_OPT_UID)
179			xtables_error(PARAMETER_PROBLEM,
180				   "Can't specify --log-uid twice");
181
182		loginfo->logflags |= IP6T_LOG_UID;
183		*flags |= IP6T_LOG_OPT_UID;
184		break;
185
186	case '5':
187		if (*flags & IP6T_LOG_OPT_MACDECODE)
188			xtables_error(PARAMETER_PROBLEM,
189				      "Can't specify --log-macdecode twice");
190
191		loginfo->logflags |= IP6T_LOG_MACDECODE;
192		*flags |= IP6T_LOG_OPT_MACDECODE;
193		break;
194	}
195
196	return 1;
197}
198
199static void LOG_print(const void *ip, const struct xt_entry_target *target,
200                      int numeric)
201{
202	const struct ip6t_log_info *loginfo
203		= (const struct ip6t_log_info *)target->data;
204	unsigned int i = 0;
205
206	printf(" LOG");
207	if (numeric)
208		printf(" flags %u level %u",
209		       loginfo->logflags, loginfo->level);
210	else {
211		for (i = 0; i < ARRAY_SIZE(ip6t_log_names); ++i)
212			if (loginfo->level == ip6t_log_names[i].level) {
213				printf(" level %s", ip6t_log_names[i].name);
214				break;
215			}
216		if (i == ARRAY_SIZE(ip6t_log_names))
217			printf(" UNKNOWN level %u", loginfo->level);
218		if (loginfo->logflags & IP6T_LOG_TCPSEQ)
219			printf(" tcp-sequence");
220		if (loginfo->logflags & IP6T_LOG_TCPOPT)
221			printf(" tcp-options");
222		if (loginfo->logflags & IP6T_LOG_IPOPT)
223			printf(" ip-options");
224		if (loginfo->logflags & IP6T_LOG_UID)
225			printf(" uid");
226		if (loginfo->logflags & IP6T_LOG_MACDECODE)
227			printf(" macdecode");
228		if (loginfo->logflags & ~(IP6T_LOG_MASK))
229			printf(" unknown-flags");
230	}
231
232	if (strcmp(loginfo->prefix, "") != 0)
233		printf(" prefix \"%s\"", loginfo->prefix);
234}
235
236static void LOG_save(const void *ip, const struct xt_entry_target *target)
237{
238	const struct ip6t_log_info *loginfo
239		= (const struct ip6t_log_info *)target->data;
240
241	if (strcmp(loginfo->prefix, "") != 0)
242		printf(" --log-prefix \"%s\"", loginfo->prefix);
243
244	if (loginfo->level != LOG_DEFAULT_LEVEL)
245		printf(" --log-level %d", loginfo->level);
246
247	if (loginfo->logflags & IP6T_LOG_TCPSEQ)
248		printf(" --log-tcp-sequence");
249	if (loginfo->logflags & IP6T_LOG_TCPOPT)
250		printf(" --log-tcp-options");
251	if (loginfo->logflags & IP6T_LOG_IPOPT)
252		printf(" --log-ip-options");
253	if (loginfo->logflags & IP6T_LOG_UID)
254		printf(" --log-uid");
255	if (loginfo->logflags & IP6T_LOG_MACDECODE)
256		printf(" --log-macdecode");
257}
258
259static struct xtables_target log_tg6_reg = {
260    .name          = "LOG",
261    .version       = XTABLES_VERSION,
262    .family        = NFPROTO_IPV6,
263    .size          = XT_ALIGN(sizeof(struct ip6t_log_info)),
264    .userspacesize = XT_ALIGN(sizeof(struct ip6t_log_info)),
265    .help          = LOG_help,
266    .init          = LOG_init,
267    .parse         = LOG_parse,
268    .print         = LOG_print,
269    .save          = LOG_save,
270    .extra_opts    = LOG_opts,
271};
272
273void _init(void)
274{
275	xtables_register_target(&log_tg6_reg);
276}
277