libipt_LOG.c revision 8115e5425721cd610b6390c3d4c24540773b0520 
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 <iptables.h>
9#include <linux/netfilter_ipv4/ip_tables.h>
10#include <linux/netfilter_ipv4/ipt_LOG.h>
11
12#define LOG_DEFAULT_LEVEL LOG_WARNING
13
14#ifndef IPT_LOG_UID /* Old kernel */
15#define IPT_LOG_UID	0x08	/* Log UID owning local socket */
16#undef  IPT_LOG_MASK
17#define IPT_LOG_MASK	0x0f
18#endif
19
20/* Function which prints out usage message. */
21static void
22help(void)
23{
24	printf(
25"LOG v%s options:\n"
26" --log-level level		Level of logging (numeric or see syslog.conf)\n"
27" --log-prefix prefix		Prefix log messages with this prefix.\n\n"
28" --log-tcp-sequence		Log TCP sequence numbers.\n\n"
29" --log-tcp-options		Log TCP options.\n\n"
30" --log-ip-options		Log IP options.\n\n"
31" --log-uid			Log UID owning the local socket.\n\n",
32IPTABLES_VERSION);
33}
34
35static struct option opts[] = {
36	{ .name = "log-level",        .has_arg = 1, .flag = 0, .val = '!' },
37	{ .name = "log-prefix",       .has_arg = 1, .flag = 0, .val = '#' },
38	{ .name = "log-tcp-sequence", .has_arg = 0, .flag = 0, .val = '1' },
39	{ .name = "log-tcp-options",  .has_arg = 0, .flag = 0, .val = '2' },
40	{ .name = "log-ip-options",   .has_arg = 0, .flag = 0, .val = '3' },
41	{ .name = "log-uid",          .has_arg = 0, .flag = 0, .val = '4' },
42	{ .name = 0 }
43};
44
45/* Initialize the target. */
46static void
47init(struct ipt_entry_target *t, unsigned int *nfcache)
48{
49	struct ipt_log_info *loginfo = (struct ipt_log_info *)t->data;
50
51	loginfo->level = LOG_DEFAULT_LEVEL;
52
53}
54
55struct ipt_log_names {
56	const char *name;
57	unsigned int level;
58};
59
60static struct ipt_log_names ipt_log_names[]
61= { { .name = "alert",   .level = LOG_ALERT },
62    { .name = "crit",    .level = LOG_CRIT },
63    { .name = "debug",   .level = LOG_DEBUG },
64    { .name = "emerg",   .level = LOG_EMERG },
65    { .name = "error",   .level = LOG_ERR },		/* DEPRECATED */
66    { .name = "info",    .level = LOG_INFO },
67    { .name = "notice",  .level = LOG_NOTICE },
68    { .name = "panic",   .level = LOG_EMERG },		/* DEPRECATED */
69    { .name = "warning", .level = LOG_WARNING }
70};
71
72static u_int8_t
73parse_level(const char *level)
74{
75	unsigned int lev = -1;
76	unsigned int set = 0;
77
78	if (string_to_number(level, 0, 7, &lev) == -1) {
79		unsigned int i = 0;
80
81		for (i = 0;
82		     i < sizeof(ipt_log_names) / sizeof(struct ipt_log_names);
83		     i++) {
84			if (strncasecmp(level, ipt_log_names[i].name,
85					strlen(level)) == 0) {
86				if (set++)
87					exit_error(PARAMETER_PROBLEM,
88						   "log-level `%s' ambiguous",
89						   level);
90				lev = ipt_log_names[i].level;
91			}
92		}
93
94		if (!set)
95			exit_error(PARAMETER_PROBLEM,
96				   "log-level `%s' unknown", level);
97	}
98
99	return (u_int8_t)lev;
100}
101
102#define IPT_LOG_OPT_LEVEL 0x01
103#define IPT_LOG_OPT_PREFIX 0x02
104#define IPT_LOG_OPT_TCPSEQ 0x04
105#define IPT_LOG_OPT_TCPOPT 0x08
106#define IPT_LOG_OPT_IPOPT 0x10
107#define IPT_LOG_OPT_UID 0x20
108
109/* Function which parses command options; returns true if it
110   ate an option */
111static int
112parse(int c, char **argv, int invert, unsigned int *flags,
113      const struct ipt_entry *entry,
114      struct ipt_entry_target **target)
115{
116	struct ipt_log_info *loginfo = (struct ipt_log_info *)(*target)->data;
117
118	switch (c) {
119	case '!':
120		if (*flags & IPT_LOG_OPT_LEVEL)
121			exit_error(PARAMETER_PROBLEM,
122				   "Can't specify --log-level twice");
123
124		if (check_inverse(optarg, &invert, NULL, 0))
125			exit_error(PARAMETER_PROBLEM,
126				   "Unexpected `!' after --log-level");
127
128		loginfo->level = parse_level(optarg);
129		*flags |= IPT_LOG_OPT_LEVEL;
130		break;
131
132	case '#':
133		if (*flags & IPT_LOG_OPT_PREFIX)
134			exit_error(PARAMETER_PROBLEM,
135				   "Can't specify --log-prefix twice");
136
137		if (check_inverse(optarg, &invert, NULL, 0))
138			exit_error(PARAMETER_PROBLEM,
139				   "Unexpected `!' after --log-prefix");
140
141		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
142			exit_error(PARAMETER_PROBLEM,
143				   "Maximum prefix length %u for --log-prefix",
144				   (unsigned int)sizeof(loginfo->prefix) - 1);
145
146		strcpy(loginfo->prefix, optarg);
147		*flags |= IPT_LOG_OPT_PREFIX;
148		break;
149
150	case '1':
151		if (*flags & IPT_LOG_OPT_TCPSEQ)
152			exit_error(PARAMETER_PROBLEM,
153				   "Can't specify --log-tcp-sequence "
154				   "twice");
155
156		loginfo->logflags |= IPT_LOG_TCPSEQ;
157		*flags |= IPT_LOG_OPT_TCPSEQ;
158		break;
159
160	case '2':
161		if (*flags & IPT_LOG_OPT_TCPOPT)
162			exit_error(PARAMETER_PROBLEM,
163				   "Can't specify --log-tcp-options twice");
164
165		loginfo->logflags |= IPT_LOG_TCPOPT;
166		*flags |= IPT_LOG_OPT_TCPOPT;
167		break;
168
169	case '3':
170		if (*flags & IPT_LOG_OPT_IPOPT)
171			exit_error(PARAMETER_PROBLEM,
172				   "Can't specify --log-ip-options twice");
173
174		loginfo->logflags |= IPT_LOG_IPOPT;
175		*flags |= IPT_LOG_OPT_IPOPT;
176		break;
177
178	case '4':
179		if (*flags & IPT_LOG_OPT_UID)
180			exit_error(PARAMETER_PROBLEM,
181				   "Can't specify --log-uid twice");
182
183		loginfo->logflags |= IPT_LOG_UID;
184		*flags |= IPT_LOG_OPT_UID;
185		break;
186
187	default:
188		return 0;
189	}
190
191	return 1;
192}
193
194/* Final check; nothing. */
195static void final_check(unsigned int flags)
196{
197}
198
199/* Prints out the targinfo. */
200static void
201print(const struct ipt_ip *ip,
202      const struct ipt_entry_target *target,
203      int numeric)
204{
205	const struct ipt_log_info *loginfo
206		= (const struct ipt_log_info *)target->data;
207	unsigned int i = 0;
208
209	printf("LOG ");
210	if (numeric)
211		printf("flags %u level %u ",
212		       loginfo->logflags, loginfo->level);
213	else {
214		for (i = 0;
215		     i < sizeof(ipt_log_names) / sizeof(struct ipt_log_names);
216		     i++) {
217			if (loginfo->level == ipt_log_names[i].level) {
218				printf("level %s ", ipt_log_names[i].name);
219				break;
220			}
221		}
222		if (i == sizeof(ipt_log_names) / sizeof(struct ipt_log_names))
223			printf("UNKNOWN level %u ", loginfo->level);
224		if (loginfo->logflags & IPT_LOG_TCPSEQ)
225			printf("tcp-sequence ");
226		if (loginfo->logflags & IPT_LOG_TCPOPT)
227			printf("tcp-options ");
228		if (loginfo->logflags & IPT_LOG_IPOPT)
229			printf("ip-options ");
230		if (loginfo->logflags & IPT_LOG_UID)
231			printf("uid ");
232		if (loginfo->logflags & ~(IPT_LOG_MASK))
233			printf("unknown-flags ");
234	}
235
236	if (strcmp(loginfo->prefix, "") != 0)
237		printf("prefix `%s' ", loginfo->prefix);
238}
239
240/* Saves the union ipt_targinfo in parsable form to stdout. */
241static void
242save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
243{
244	const struct ipt_log_info *loginfo
245		= (const struct ipt_log_info *)target->data;
246
247	if (strcmp(loginfo->prefix, "") != 0)
248		printf("--log-prefix \"%s\" ", loginfo->prefix);
249
250	if (loginfo->level != LOG_DEFAULT_LEVEL)
251		printf("--log-level %d ", loginfo->level);
252
253	if (loginfo->logflags & IPT_LOG_TCPSEQ)
254		printf("--log-tcp-sequence ");
255	if (loginfo->logflags & IPT_LOG_TCPOPT)
256		printf("--log-tcp-options ");
257	if (loginfo->logflags & IPT_LOG_IPOPT)
258		printf("--log-ip-options ");
259	if (loginfo->logflags & IPT_LOG_UID)
260		printf("--log-uid ");
261}
262
263static
264struct iptables_target log
265= {
266    .name          = "LOG",
267    .version       = IPTABLES_VERSION,
268    .size          = IPT_ALIGN(sizeof(struct ipt_log_info)),
269    .userspacesize = IPT_ALIGN(sizeof(struct ipt_log_info)),
270    .help          = &help,
271    .init          = &init,
272    .parse         = &parse,
273    .final_check   = &final_check,
274    .print         = &print,
275    .save          = &save,
276    .extra_opts    = opts
277};
278
279void _init(void)
280{
281	register_target(&log);
282}
283