libxt_comment.c revision 18992db3bfdb3b695cae12b53434f560cbf8e2ae 
1/* Shared library add-on to iptables to add comment match support.
2 *
3 * ChangeLog
4 *     2003-05-13: Brad Fisher <brad@info-link.net>
5 *         Initial comment match
6 *     2004-05-12: Brad Fisher <brad@info-link.net>
7 *         Port to patch-o-matic-ng
8 */
9#include <stdio.h>
10#include <string.h>
11#include <stdlib.h>
12#include <getopt.h>
13
14#include <xtables.h>
15#include <linux/netfilter/xt_comment.h>
16
17/* Function which prints out usage message. */
18static void
19help(void)
20{
21	printf(
22		"COMMENT match options:\n"
23		"--comment COMMENT             Attach a comment to a rule\n\n"
24		);
25}
26
27static struct option opts[] = {
28	{ "comment", 1, 0, '1' },
29	{0}
30};
31
32static void
33parse_comment(const char *s, struct xt_comment_info *info)
34{
35	int slen = strlen(s);
36
37	if (slen >= XT_MAX_COMMENT_LEN) {
38		exit_error(PARAMETER_PROBLEM,
39			"COMMENT must be shorter than %i characters", XT_MAX_COMMENT_LEN);
40	}
41	strcpy((char *)info->comment, s);
42}
43
44/* Function which parses command options; returns true if it
45   ate an option */
46static int
47parse(int c, char **argv, int invert, unsigned int *flags,
48      const void *entry,
49      unsigned int *nfcache,
50      struct xt_entry_match **match)
51{
52	struct xt_comment_info *commentinfo = (struct xt_comment_info *)(*match)->data;
53
54	switch (c) {
55	case '1':
56		check_inverse(argv[optind-1], &invert, &optind, 0);
57		if (invert) {
58			exit_error(PARAMETER_PROBLEM,
59					"Sorry, you can't have an inverted comment");
60		}
61		parse_comment(argv[optind-1], commentinfo);
62		*flags = 1;
63		break;
64
65	default:
66		return 0;
67	}
68	return 1;
69}
70
71/* Final check; must have specified --comment. */
72static void
73final_check(unsigned int flags)
74{
75	if (!flags)
76		exit_error(PARAMETER_PROBLEM,
77			   "COMMENT match: You must specify `--comment'");
78}
79
80/* Prints out the matchinfo. */
81static void
82print(const void *ip,
83      const struct xt_entry_match *match,
84      int numeric)
85{
86	struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
87
88	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
89	printf("/* %s */ ", commentinfo->comment);
90}
91
92/* Saves the union ipt_matchinfo in parsable form to stdout. */
93static void
94save(const void *ip, const struct xt_entry_match *match)
95{
96	struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
97
98	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
99	printf("--comment \"%s\" ", commentinfo->comment);
100}
101
102static struct xtables_match comment = {
103	.family		= AF_INET,
104	.name		= "comment",
105	.version	= IPTABLES_VERSION,
106	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
107	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
108	.help		= &help,
109	.parse		= &parse,
110	.final_check	= &final_check,
111	.print 		= &print,
112	.save 		= &save,
113	.extra_opts	= opts
114};
115
116static struct xtables_match comment6 = {
117	.family		= AF_INET6,
118	.name		= "comment",
119	.version	= IPTABLES_VERSION,
120	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
121	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
122	.help		= &help,
123	.parse		= &parse,
124	.final_check	= &final_check,
125	.print 		= &print,
126	.save 		= &save,
127	.extra_opts	= opts
128};
129
130void _init(void)
131{
132	xtables_register_match(&comment);
133	xtables_register_match(&comment6);
134}
135