libip6t_LOG.c revision 8b7c64d6ba156a99008fcd810cba874c73294333 
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 target 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"
27" --log-tcp-sequence		Log TCP sequence numbers.\n"
28" --log-tcp-options		Log TCP options.\n"
29" --log-ip-options		Log IP options.\n"
30" --log-uid			Log UID owning the local socket.\n");
31}
32
33static const struct option LOG_opts[] = {
34	{ .name = "log-level",        .has_arg = 1, .val = '!' },
35	{ .name = "log-prefix",       .has_arg = 1, .val = '#' },
36	{ .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
37	{ .name = "log-tcp-options",  .has_arg = 0, .val = '2' },
38	{ .name = "log-ip-options",   .has_arg = 0, .val = '3' },
39	{ .name = "log-uid",          .has_arg = 0, .val = '4' },
40	{ .name = NULL }
41};
42
43/* Initialize the target. */
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 u_int8_t
70parse_level(const char *level)
71{
72	unsigned int lev = -1;
73	unsigned int set = 0;
74
75	if (string_to_number(level, 0, 7, &lev) == -1) {
76		unsigned int i = 0;
77
78		for (i = 0;
79		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
80		     i++) {
81			if (strncasecmp(level, ip6t_log_names[i].name,
82					strlen(level)) == 0) {
83				if (set++)
84					exit_error(PARAMETER_PROBLEM,
85						   "log-level `%s' ambiguous",
86						   level);
87				lev = ip6t_log_names[i].level;
88			}
89		}
90
91		if (!set)
92			exit_error(PARAMETER_PROBLEM,
93				   "log-level `%s' unknown", level);
94	}
95
96	return (u_int8_t)lev;
97}
98
99#define IP6T_LOG_OPT_LEVEL 0x01
100#define IP6T_LOG_OPT_PREFIX 0x02
101#define IP6T_LOG_OPT_TCPSEQ 0x04
102#define IP6T_LOG_OPT_TCPOPT 0x08
103#define IP6T_LOG_OPT_IPOPT 0x10
104#define IP6T_LOG_OPT_UID 0x20
105
106/* Function which parses command options; returns true if it
107   ate an option */
108static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
109                     const void *entry, struct xt_entry_target **target)
110{
111	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
112
113	switch (c) {
114	case '!':
115		if (*flags & IP6T_LOG_OPT_LEVEL)
116			exit_error(PARAMETER_PROBLEM,
117				   "Can't specify --log-level twice");
118
119		if (check_inverse(optarg, &invert, NULL, 0))
120			exit_error(PARAMETER_PROBLEM,
121				   "Unexpected `!' after --log-level");
122
123		loginfo->level = parse_level(optarg);
124		*flags |= IP6T_LOG_OPT_LEVEL;
125		break;
126
127	case '#':
128		if (*flags & IP6T_LOG_OPT_PREFIX)
129			exit_error(PARAMETER_PROBLEM,
130				   "Can't specify --log-prefix twice");
131
132		if (check_inverse(optarg, &invert, NULL, 0))
133			exit_error(PARAMETER_PROBLEM,
134				   "Unexpected `!' after --log-prefix");
135
136		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
137			exit_error(PARAMETER_PROBLEM,
138				   "Maximum prefix length %u for --log-prefix",
139				   (unsigned int)sizeof(loginfo->prefix) - 1);
140
141		if (strlen(optarg) == 0)
142			exit_error(PARAMETER_PROBLEM,
143				   "No prefix specified for --log-prefix");
144
145		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
146			exit_error(PARAMETER_PROBLEM,
147				   "Newlines not allowed in --log-prefix");
148
149		strcpy(loginfo->prefix, optarg);
150		*flags |= IP6T_LOG_OPT_PREFIX;
151		break;
152
153	case '1':
154		if (*flags & IP6T_LOG_OPT_TCPSEQ)
155			exit_error(PARAMETER_PROBLEM,
156				   "Can't specify --log-tcp-sequence "
157				   "twice");
158
159		loginfo->logflags |= IP6T_LOG_TCPSEQ;
160		*flags |= IP6T_LOG_OPT_TCPSEQ;
161		break;
162
163	case '2':
164		if (*flags & IP6T_LOG_OPT_TCPOPT)
165			exit_error(PARAMETER_PROBLEM,
166				   "Can't specify --log-tcp-options twice");
167
168		loginfo->logflags |= IP6T_LOG_TCPOPT;
169		*flags |= IP6T_LOG_OPT_TCPOPT;
170		break;
171
172	case '3':
173		if (*flags & IP6T_LOG_OPT_IPOPT)
174			exit_error(PARAMETER_PROBLEM,
175				   "Can't specify --log-ip-options twice");
176
177		loginfo->logflags |= IP6T_LOG_IPOPT;
178		*flags |= IP6T_LOG_OPT_IPOPT;
179		break;
180
181	case '4':
182		if (*flags & IP6T_LOG_OPT_UID)
183			exit_error(PARAMETER_PROBLEM,
184				   "Can't specify --log-uid twice");
185
186		loginfo->logflags |= IP6T_LOG_UID;
187		*flags |= IP6T_LOG_OPT_UID;
188		break;
189
190	default:
191		return 0;
192	}
193
194	return 1;
195}
196
197/* Prints out the targinfo. */
198static void LOG_print(const void *ip, const struct xt_entry_target *target,
199                      int numeric)
200{
201	const struct ip6t_log_info *loginfo
202		= (const struct ip6t_log_info *)target->data;
203	unsigned int i = 0;
204
205	printf("LOG ");
206	if (numeric)
207		printf("flags %u level %u ",
208		       loginfo->logflags, loginfo->level);
209	else {
210		for (i = 0;
211		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
212		     i++) {
213			if (loginfo->level == ip6t_log_names[i].level) {
214				printf("level %s ", ip6t_log_names[i].name);
215				break;
216			}
217		}
218		if (i == sizeof(ip6t_log_names) / sizeof(struct 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_MASK))
229			printf("unknown-flags ");
230	}
231
232	if (strcmp(loginfo->prefix, "") != 0)
233		printf("prefix `%s' ", loginfo->prefix);
234}
235
236/* Saves the union ip6t_targinfo in parsable form to stdout. */
237static void LOG_save(const void *ip, const struct xt_entry_target *target)
238{
239	const struct ip6t_log_info *loginfo
240		= (const struct ip6t_log_info *)target->data;
241
242	if (strcmp(loginfo->prefix, "") != 0)
243		printf("--log-prefix \"%s\" ", loginfo->prefix);
244
245	if (loginfo->level != LOG_DEFAULT_LEVEL)
246		printf("--log-level %d ", loginfo->level);
247
248	if (loginfo->logflags & IP6T_LOG_TCPSEQ)
249		printf("--log-tcp-sequence ");
250	if (loginfo->logflags & IP6T_LOG_TCPOPT)
251		printf("--log-tcp-options ");
252	if (loginfo->logflags & IP6T_LOG_IPOPT)
253		printf("--log-ip-options ");
254	if (loginfo->logflags & IP6T_LOG_UID)
255		printf("--log-uid ");
256}
257
258static struct xtables_target log_tg6_reg = {
259    .name          = "LOG",
260    .version       = XTABLES_VERSION,
261    .family        = PF_INET6,
262    .size          = XT_ALIGN(sizeof(struct ip6t_log_info)),
263    .userspacesize = XT_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	xtables_register_target(&log_tg6_reg);
275}
276