libip6t_LOG.c revision 9ee386a1b6d7704b259460152c959ab0e79e02aa 
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 <ip6tables.h>
9#include <linux/netfilter_ipv6/ip6_tables.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
20/* Function which prints out usage message. */
21static void LOG_help(void)
22{
23	printf(
24"LOG v%s options:\n"
25" --log-level level		Level of logging (numeric or see syslog.conf)\n"
26" --log-prefix prefix		Prefix log messages with this prefix.\n\n"
27" --log-tcp-sequence		Log TCP sequence numbers.\n\n"
28" --log-tcp-options		Log TCP options.\n\n"
29" --log-ip-options		Log IP options.\n\n"
30" --log-uid			Log UID owning the local socket.\n\n",
31IPTABLES_VERSION);
32}
33
34static const struct option LOG_opts[] = {
35	{ .name = "log-level",        .has_arg = 1, .val = '!' },
36	{ .name = "log-prefix",       .has_arg = 1, .val = '#' },
37	{ .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
38	{ .name = "log-tcp-options",  .has_arg = 0, .val = '2' },
39	{ .name = "log-ip-options",   .has_arg = 0, .val = '3' },
40	{ .name = "log-uid",          .has_arg = 0, .val = '4' },
41	{ .name = NULL }
42};
43
44/* Initialize the target. */
45static void LOG_init(struct xt_entry_target *t)
46{
47	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
48
49	loginfo->level = LOG_DEFAULT_LEVEL;
50
51}
52
53struct ip6t_log_names {
54	const char *name;
55	unsigned int level;
56};
57
58static const struct ip6t_log_names ip6t_log_names[]
59= { { .name = "alert",   .level = LOG_ALERT },
60    { .name = "crit",    .level = LOG_CRIT },
61    { .name = "debug",   .level = LOG_DEBUG },
62    { .name = "emerg",   .level = LOG_EMERG },
63    { .name = "error",   .level = LOG_ERR },		/* DEPRECATED */
64    { .name = "info",    .level = LOG_INFO },
65    { .name = "notice",  .level = LOG_NOTICE },
66    { .name = "panic",   .level = LOG_EMERG },		/* DEPRECATED */
67    { .name = "warning", .level = LOG_WARNING }
68};
69
70static u_int8_t
71parse_level(const char *level)
72{
73	unsigned int lev = -1;
74	unsigned int set = 0;
75
76	if (string_to_number(level, 0, 7, &lev) == -1) {
77		unsigned int i = 0;
78
79		for (i = 0;
80		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
81		     i++) {
82			if (strncasecmp(level, ip6t_log_names[i].name,
83					strlen(level)) == 0) {
84				if (set++)
85					exit_error(PARAMETER_PROBLEM,
86						   "log-level `%s' ambiguous",
87						   level);
88				lev = ip6t_log_names[i].level;
89			}
90		}
91
92		if (!set)
93			exit_error(PARAMETER_PROBLEM,
94				   "log-level `%s' unknown", level);
95	}
96
97	return (u_int8_t)lev;
98}
99
100#define IP6T_LOG_OPT_LEVEL 0x01
101#define IP6T_LOG_OPT_PREFIX 0x02
102#define IP6T_LOG_OPT_TCPSEQ 0x04
103#define IP6T_LOG_OPT_TCPOPT 0x08
104#define IP6T_LOG_OPT_IPOPT 0x10
105#define IP6T_LOG_OPT_UID 0x20
106
107/* Function which parses command options; returns true if it
108   ate an option */
109static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
110                     const void *entry, struct xt_entry_target **target)
111{
112	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
113
114	switch (c) {
115	case '!':
116		if (*flags & IP6T_LOG_OPT_LEVEL)
117			exit_error(PARAMETER_PROBLEM,
118				   "Can't specify --log-level twice");
119
120		if (check_inverse(optarg, &invert, NULL, 0))
121			exit_error(PARAMETER_PROBLEM,
122				   "Unexpected `!' after --log-level");
123
124		loginfo->level = parse_level(optarg);
125		*flags |= IP6T_LOG_OPT_LEVEL;
126		break;
127
128	case '#':
129		if (*flags & IP6T_LOG_OPT_PREFIX)
130			exit_error(PARAMETER_PROBLEM,
131				   "Can't specify --log-prefix twice");
132
133		if (check_inverse(optarg, &invert, NULL, 0))
134			exit_error(PARAMETER_PROBLEM,
135				   "Unexpected `!' after --log-prefix");
136
137		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
138			exit_error(PARAMETER_PROBLEM,
139				   "Maximum prefix length %u for --log-prefix",
140				   (unsigned int)sizeof(loginfo->prefix) - 1);
141
142		if (strlen(optarg) == 0)
143			exit_error(PARAMETER_PROBLEM,
144				   "No prefix specified for --log-prefix");
145
146		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
147			exit_error(PARAMETER_PROBLEM,
148				   "Newlines not allowed in --log-prefix");
149
150		strcpy(loginfo->prefix, optarg);
151		*flags |= IP6T_LOG_OPT_PREFIX;
152		break;
153
154	case '1':
155		if (*flags & IP6T_LOG_OPT_TCPSEQ)
156			exit_error(PARAMETER_PROBLEM,
157				   "Can't specify --log-tcp-sequence "
158				   "twice");
159
160		loginfo->logflags |= IP6T_LOG_TCPSEQ;
161		*flags |= IP6T_LOG_OPT_TCPSEQ;
162		break;
163
164	case '2':
165		if (*flags & IP6T_LOG_OPT_TCPOPT)
166			exit_error(PARAMETER_PROBLEM,
167				   "Can't specify --log-tcp-options twice");
168
169		loginfo->logflags |= IP6T_LOG_TCPOPT;
170		*flags |= IP6T_LOG_OPT_TCPOPT;
171		break;
172
173	case '3':
174		if (*flags & IP6T_LOG_OPT_IPOPT)
175			exit_error(PARAMETER_PROBLEM,
176				   "Can't specify --log-ip-options twice");
177
178		loginfo->logflags |= IP6T_LOG_IPOPT;
179		*flags |= IP6T_LOG_OPT_IPOPT;
180		break;
181
182	case '4':
183		if (*flags & IP6T_LOG_OPT_UID)
184			exit_error(PARAMETER_PROBLEM,
185				   "Can't specify --log-uid twice");
186
187		loginfo->logflags |= IP6T_LOG_UID;
188		*flags |= IP6T_LOG_OPT_UID;
189		break;
190
191	default:
192		return 0;
193	}
194
195	return 1;
196}
197
198/* Prints out the targinfo. */
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;
212		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
213		     i++) {
214			if (loginfo->level == ip6t_log_names[i].level) {
215				printf("level %s ", ip6t_log_names[i].name);
216				break;
217			}
218		}
219		if (i == sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names))
220			printf("UNKNOWN level %u ", loginfo->level);
221		if (loginfo->logflags & IP6T_LOG_TCPSEQ)
222			printf("tcp-sequence ");
223		if (loginfo->logflags & IP6T_LOG_TCPOPT)
224			printf("tcp-options ");
225		if (loginfo->logflags & IP6T_LOG_IPOPT)
226			printf("ip-options ");
227		if (loginfo->logflags & IP6T_LOG_UID)
228			printf("uid ");
229		if (loginfo->logflags & ~(IP6T_LOG_MASK))
230			printf("unknown-flags ");
231	}
232
233	if (strcmp(loginfo->prefix, "") != 0)
234		printf("prefix `%s' ", loginfo->prefix);
235}
236
237/* Saves the union ip6t_targinfo in parsable form to stdout. */
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}
258
259static struct ip6tables_target log_target6 = {
260    .name          = "LOG",
261    .version       = IPTABLES_VERSION,
262    .size          = IP6T_ALIGN(sizeof(struct ip6t_log_info)),
263    .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_log_info)),
264    .help          = LOG_help,
265    .init          = LOG_init,
266    .parse         = LOG_parse,
267    .print         = LOG_print,
268    .save          = LOG_save,
269    .extra_opts    = LOG_opts,
270};
271
272void _init(void)
273{
274	register_target6(&log_target6);
275}
276