libipt_ULOG.c revision 67f23b2b40e937b3a20b4de4aa7bad7d2768e68e 
1/* Shared library add-on to iptables to add ULOG support.
2 *
3 * (C) 2000 by Harald Welte <laforge@sunbeam.franken.de>
4 *
5 * This software is released under the terms of GNU GPL
6 *
7 * libipt_ULOG.c,v 1.3 2000/07/31 11:51:50 laforge Exp
8 */
9#include <stdio.h>
10#include <netdb.h>
11#include <string.h>
12#include <stdlib.h>
13#include <syslog.h>
14#include <getopt.h>
15#include <iptables.h>
16#include <linux/netfilter_ipv4/ip_tables.h>
17#include <linux/netfilter_ipv4/ipt_ULOG.h>
18
19#define ULOG_DEFAULT_NLGROUP 1
20
21
22void print_groups(unsigned int gmask)
23{
24	int b;
25	unsigned int test;
26
27	for (b = 31; b >= 0; b--) {
28		test = (1 << b);
29		if (gmask & test)
30			printf("%d ", b + 1);
31	}
32}
33
34/* Function which prints out usage message. */
35static void help(void)
36{
37	printf("ULOG v%s options:\n"
38	       " --ulog-nlgroup nlgroup		NETLINK group used for logging\n"
39	       " --ulog-cprange size		Bytes of each packet to be passed\n"
40	       " --ulog-prefix prefix		Prefix log messages with this prefix.\n\n",
41	       NETFILTER_VERSION);
42}
43
44static struct option opts[] = {
45	{"ulog-nlgroup", 1, 0, '!'},
46	{"ulog-prefix", 1, 0, '#'},
47	{"ulog-cprange", 1, 0, 'A'},
48	{0}
49};
50
51/* Initialize the target. */
52static void init(struct ipt_entry_target *t, unsigned int *nfcache)
53{
54	struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) t->data;
55
56	loginfo->nl_group = ULOG_DEFAULT_NLGROUP;
57
58	/* Can't cache this */
59	*nfcache |= NFC_UNKNOWN;
60}
61
62#define IPT_LOG_OPT_NLGROUP 0x01
63#define IPT_LOG_OPT_PREFIX 0x02
64#define IPT_LOG_OPT_CPRANGE 0x04
65
66/* Function which parses command options; returns true if it
67   ate an option */
68static int parse(int c, char **argv, int invert, unsigned int *flags,
69		 const struct ipt_entry *entry,
70		 struct ipt_entry_target **target)
71{
72	struct ipt_ulog_info *loginfo =
73	    (struct ipt_ulog_info *) (*target)->data;
74	int group_d;
75
76	switch (c) {
77	case '!':
78		if (*flags & IPT_LOG_OPT_NLGROUP)
79			exit_error(PARAMETER_PROBLEM,
80				   "Can't specify --ulog-nlgroup twice");
81
82		if (check_inverse(optarg, &invert))
83			exit_error(PARAMETER_PROBLEM,
84				   "Unexpected `!' after --ulog-nlgroup");
85		group_d = atoi(optarg);
86		if (group_d > 32 || group_d < 1)
87			exit_error(PARAMETER_PROBLEM,
88				   "--ulog-nlgroup has to be between 1 and 32");
89
90		loginfo->nl_group = (1 << (group_d - 1));
91
92		*flags |= IPT_LOG_OPT_NLGROUP;
93		break;
94
95	case '#':
96		if (*flags & IPT_LOG_OPT_PREFIX)
97			exit_error(PARAMETER_PROBLEM,
98				   "Can't specify --ulog-prefix twice");
99
100		if (check_inverse(optarg, &invert))
101			exit_error(PARAMETER_PROBLEM,
102				   "Unexpected `!' after --ulog-prefix");
103
104		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
105			exit_error(PARAMETER_PROBLEM,
106				   "Maximum prefix length %u for --ulog-prefix",
107				   sizeof(loginfo->prefix) - 1);
108
109		strcpy(loginfo->prefix, optarg);
110		*flags |= IPT_LOG_OPT_PREFIX;
111		break;
112	case 'A':
113		if (*flags & IPT_LOG_OPT_CPRANGE)
114			exit_error(PARAMETER_PROBLEM,
115				   "Can't specify --ulog-cprange twice");
116		if (atoi(optarg) < 0)
117			exit_error(PARAMETER_PROBLEM,
118				   "Negative copy range?");
119		loginfo->copy_range = atoi(optarg);
120		*flags |= IPT_LOG_OPT_CPRANGE;
121		break;
122	}
123	return 1;
124}
125
126/* Final check; nothing. */
127static void final_check(unsigned int flags)
128{
129}
130
131/* Saves the union ipt_targinfo in parsable form to stdout. */
132static void save(const struct ipt_ip *ip,
133		 const struct ipt_entry_target *target)
134{
135	const struct ipt_ulog_info *loginfo
136	    = (const struct ipt_ulog_info *) target->data;
137
138	if (strcmp(loginfo->prefix, "") != 0)
139		printf("--ulog-prefix %s ", loginfo->prefix);
140
141	if (loginfo->nl_group != ULOG_DEFAULT_NLGROUP) {
142		printf("--ulog-nlgroup ");
143		print_groups(loginfo->nl_group);
144		printf("\n");
145	}
146	if (loginfo->copy_range)
147		printf("--ulog-cprange %d", loginfo->copy_range);
148}
149
150/* Prints out the targinfo. */
151static void
152print(const struct ipt_ip *ip,
153      const struct ipt_entry_target *target, int numeric)
154{
155	const struct ipt_ulog_info *loginfo
156	    = (const struct ipt_ulog_info *) target->data;
157
158	printf("ULOG ");
159	printf("copy_range %d nlgroup ", loginfo->copy_range);
160	print_groups(loginfo->nl_group);
161	if (strcmp(loginfo->prefix, "") != 0)
162		printf("prefix `%s' ", loginfo->prefix);
163}
164
165struct iptables_target ulog = { NULL,
166	"ULOG",
167	NETFILTER_VERSION,
168	IPT_ALIGN(sizeof(struct ipt_ulog_info)),
169	IPT_ALIGN(sizeof(struct ipt_ulog_info)),
170	&help,
171	&init,
172	&parse,
173	&final_check,
174	&print,
175	&save,
176	opts
177};
178
179void _init(void)
180{
181	register_target(&ulog);
182}
183