libip6t_LOG.c revision bf97128c7262f17a02fec41cdae75b472ba77f88 
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}
30
31static const struct option LOG_opts[] = {
32	{ .name = "log-level",        .has_arg = 1, .val = '!' },
33	{ .name = "log-prefix",       .has_arg = 1, .val = '#' },
34	{ .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
35	{ .name = "log-tcp-options",  .has_arg = 0, .val = '2' },
36	{ .name = "log-ip-options",   .has_arg = 0, .val = '3' },
37	{ .name = "log-uid",          .has_arg = 0, .val = '4' },
38	{ .name = NULL }
39};
40
41static void LOG_init(struct xt_entry_target *t)
42{
43	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
44
45	loginfo->level = LOG_DEFAULT_LEVEL;
46
47}
48
49struct ip6t_log_names {
50	const char *name;
51	unsigned int level;
52};
53
54static const struct ip6t_log_names ip6t_log_names[]
55= { { .name = "alert",   .level = LOG_ALERT },
56    { .name = "crit",    .level = LOG_CRIT },
57    { .name = "debug",   .level = LOG_DEBUG },
58    { .name = "emerg",   .level = LOG_EMERG },
59    { .name = "error",   .level = LOG_ERR },		/* DEPRECATED */
60    { .name = "info",    .level = LOG_INFO },
61    { .name = "notice",  .level = LOG_NOTICE },
62    { .name = "panic",   .level = LOG_EMERG },		/* DEPRECATED */
63    { .name = "warning", .level = LOG_WARNING }
64};
65
66static u_int8_t
67parse_level(const char *level)
68{
69	unsigned int lev = -1;
70	unsigned int set = 0;
71
72	if (!xtables_strtoui(level, NULL, &lev, 0, 7)) {
73		unsigned int i = 0;
74
75		for (i = 0; i < ARRAY_SIZE(ip6t_log_names); ++i)
76			if (strncasecmp(level, ip6t_log_names[i].name,
77					strlen(level)) == 0) {
78				if (set++)
79					xtables_error(PARAMETER_PROBLEM,
80						   "log-level `%s' ambiguous",
81						   level);
82				lev = ip6t_log_names[i].level;
83			}
84
85		if (!set)
86			xtables_error(PARAMETER_PROBLEM,
87				   "log-level `%s' unknown", level);
88	}
89
90	return lev;
91}
92
93#define IP6T_LOG_OPT_LEVEL 0x01
94#define IP6T_LOG_OPT_PREFIX 0x02
95#define IP6T_LOG_OPT_TCPSEQ 0x04
96#define IP6T_LOG_OPT_TCPOPT 0x08
97#define IP6T_LOG_OPT_IPOPT 0x10
98#define IP6T_LOG_OPT_UID 0x20
99
100static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
101                     const void *entry, struct xt_entry_target **target)
102{
103	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
104
105	switch (c) {
106	case '!':
107		if (*flags & IP6T_LOG_OPT_LEVEL)
108			xtables_error(PARAMETER_PROBLEM,
109				   "Can't specify --log-level twice");
110
111		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
112			xtables_error(PARAMETER_PROBLEM,
113				   "Unexpected `!' after --log-level");
114
115		loginfo->level = parse_level(optarg);
116		*flags |= IP6T_LOG_OPT_LEVEL;
117		break;
118
119	case '#':
120		if (*flags & IP6T_LOG_OPT_PREFIX)
121			xtables_error(PARAMETER_PROBLEM,
122				   "Can't specify --log-prefix twice");
123
124		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
125			xtables_error(PARAMETER_PROBLEM,
126				   "Unexpected `!' after --log-prefix");
127
128		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
129			xtables_error(PARAMETER_PROBLEM,
130				   "Maximum prefix length %u for --log-prefix",
131				   (unsigned int)sizeof(loginfo->prefix) - 1);
132
133		if (strlen(optarg) == 0)
134			xtables_error(PARAMETER_PROBLEM,
135				   "No prefix specified for --log-prefix");
136
137		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
138			xtables_error(PARAMETER_PROBLEM,
139				   "Newlines not allowed in --log-prefix");
140
141		strcpy(loginfo->prefix, optarg);
142		*flags |= IP6T_LOG_OPT_PREFIX;
143		break;
144
145	case '1':
146		if (*flags & IP6T_LOG_OPT_TCPSEQ)
147			xtables_error(PARAMETER_PROBLEM,
148				   "Can't specify --log-tcp-sequence "
149				   "twice");
150
151		loginfo->logflags |= IP6T_LOG_TCPSEQ;
152		*flags |= IP6T_LOG_OPT_TCPSEQ;
153		break;
154
155	case '2':
156		if (*flags & IP6T_LOG_OPT_TCPOPT)
157			xtables_error(PARAMETER_PROBLEM,
158				   "Can't specify --log-tcp-options twice");
159
160		loginfo->logflags |= IP6T_LOG_TCPOPT;
161		*flags |= IP6T_LOG_OPT_TCPOPT;
162		break;
163
164	case '3':
165		if (*flags & IP6T_LOG_OPT_IPOPT)
166			xtables_error(PARAMETER_PROBLEM,
167				   "Can't specify --log-ip-options twice");
168
169		loginfo->logflags |= IP6T_LOG_IPOPT;
170		*flags |= IP6T_LOG_OPT_IPOPT;
171		break;
172
173	case '4':
174		if (*flags & IP6T_LOG_OPT_UID)
175			xtables_error(PARAMETER_PROBLEM,
176				   "Can't specify --log-uid twice");
177
178		loginfo->logflags |= IP6T_LOG_UID;
179		*flags |= IP6T_LOG_OPT_UID;
180		break;
181
182	default:
183		return 0;
184	}
185
186	return 1;
187}
188
189static void LOG_print(const void *ip, const struct xt_entry_target *target,
190                      int numeric)
191{
192	const struct ip6t_log_info *loginfo
193		= (const struct ip6t_log_info *)target->data;
194	unsigned int i = 0;
195
196	printf("LOG ");
197	if (numeric)
198		printf("flags %u level %u ",
199		       loginfo->logflags, loginfo->level);
200	else {
201		for (i = 0; i < ARRAY_SIZE(ip6t_log_names); ++i)
202			if (loginfo->level == ip6t_log_names[i].level) {
203				printf("level %s ", ip6t_log_names[i].name);
204				break;
205			}
206		if (i == ARRAY_SIZE(ip6t_log_names))
207			printf("UNKNOWN level %u ", loginfo->level);
208		if (loginfo->logflags & IP6T_LOG_TCPSEQ)
209			printf("tcp-sequence ");
210		if (loginfo->logflags & IP6T_LOG_TCPOPT)
211			printf("tcp-options ");
212		if (loginfo->logflags & IP6T_LOG_IPOPT)
213			printf("ip-options ");
214		if (loginfo->logflags & IP6T_LOG_UID)
215			printf("uid ");
216		if (loginfo->logflags & ~(IP6T_LOG_MASK))
217			printf("unknown-flags ");
218	}
219
220	if (strcmp(loginfo->prefix, "") != 0)
221		printf("prefix `%s' ", loginfo->prefix);
222}
223
224static void LOG_save(const void *ip, const struct xt_entry_target *target)
225{
226	const struct ip6t_log_info *loginfo
227		= (const struct ip6t_log_info *)target->data;
228
229	if (strcmp(loginfo->prefix, "") != 0)
230		printf("--log-prefix \"%s\" ", loginfo->prefix);
231
232	if (loginfo->level != LOG_DEFAULT_LEVEL)
233		printf("--log-level %d ", loginfo->level);
234
235	if (loginfo->logflags & IP6T_LOG_TCPSEQ)
236		printf("--log-tcp-sequence ");
237	if (loginfo->logflags & IP6T_LOG_TCPOPT)
238		printf("--log-tcp-options ");
239	if (loginfo->logflags & IP6T_LOG_IPOPT)
240		printf("--log-ip-options ");
241	if (loginfo->logflags & IP6T_LOG_UID)
242		printf("--log-uid ");
243}
244
245static struct xtables_target log_tg6_reg = {
246    .name          = "LOG",
247    .version       = XTABLES_VERSION,
248    .family        = NFPROTO_IPV6,
249    .size          = XT_ALIGN(sizeof(struct ip6t_log_info)),
250    .userspacesize = XT_ALIGN(sizeof(struct ip6t_log_info)),
251    .help          = LOG_help,
252    .init          = LOG_init,
253    .parse         = LOG_parse,
254    .print         = LOG_print,
255    .save          = LOG_save,
256    .extra_opts    = LOG_opts,
257};
258
259void _init(void)
260{
261	xtables_register_target(&log_tg6_reg);
262}
263