libxt_comment.c revision bf97128c7262f17a02fec41cdae75b472ba77f88 
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
17static void comment_help(void)
18{
19	printf(
20		"comment match options:\n"
21		"--comment COMMENT             Attach a comment to a rule\n");
22}
23
24static const struct option comment_opts[] = {
25	{ "comment", 1, NULL, '1' },
26	{ .name = NULL }
27};
28
29static void
30parse_comment(const char *s, struct xt_comment_info *info)
31{
32	int slen = strlen(s);
33
34	if (slen >= XT_MAX_COMMENT_LEN) {
35		xtables_error(PARAMETER_PROBLEM,
36			"COMMENT must be shorter than %i characters", XT_MAX_COMMENT_LEN);
37	}
38	strcpy((char *)info->comment, s);
39}
40
41static int
42comment_parse(int c, char **argv, int invert, unsigned int *flags,
43              const void *entry, struct xt_entry_match **match)
44{
45	struct xt_comment_info *commentinfo = (struct xt_comment_info *)(*match)->data;
46
47	switch (c) {
48	case '1':
49		xtables_check_inverse(argv[optind-1], &invert, &optind, 0, argv);
50		if (invert) {
51			xtables_error(PARAMETER_PROBLEM,
52					"Sorry, you can't have an inverted comment");
53		}
54		parse_comment(argv[optind-1], commentinfo);
55		*flags = 1;
56		break;
57
58	default:
59		return 0;
60	}
61	return 1;
62}
63
64static void comment_check(unsigned int flags)
65{
66	if (!flags)
67		xtables_error(PARAMETER_PROBLEM,
68			   "COMMENT match: You must specify `--comment'");
69}
70
71static void
72comment_print(const void *ip, const struct xt_entry_match *match, int numeric)
73{
74	struct xt_comment_info *commentinfo = (void *)match->data;
75
76	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
77	printf("/* %s */ ", commentinfo->comment);
78}
79
80/* Saves the union ipt_matchinfo in parsable form to stdout. */
81static void
82comment_save(const void *ip, const struct xt_entry_match *match)
83{
84	struct xt_comment_info *commentinfo = (void *)match->data;
85
86	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
87	printf("--comment ");
88	xtables_save_string((const char *)commentinfo->comment);
89}
90
91static struct xtables_match comment_match = {
92	.family		= NFPROTO_UNSPEC,
93	.name		= "comment",
94	.version	= XTABLES_VERSION,
95	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
96	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
97	.help		= comment_help,
98	.parse		= comment_parse,
99	.final_check	= comment_check,
100	.print 		= comment_print,
101	.save 		= comment_save,
102	.extra_opts	= comment_opts,
103};
104
105void _init(void)
106{
107	xtables_register_match(&comment_match);
108}
109