libxt_comment.c revision 32b8e61e4e5bd405d9ad07bf9468498dfbb19f9e 
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 <stdbool.h>
10#include <stdio.h>
11#include <string.h>
12#include <stdlib.h>
13#include <getopt.h>
14
15#include <xtables.h>
16#include <linux/netfilter/xt_comment.h>
17
18static void comment_help(void)
19{
20	printf(
21		"comment match options:\n"
22		"--comment COMMENT             Attach a comment to a rule\n");
23}
24
25static const struct option comment_opts[] = {
26	{.name = "comment", .has_arg = true, .val = '1'},
27	XT_GETOPT_TABLEEND,
28};
29
30static void
31parse_comment(const char *s, struct xt_comment_info *info)
32{
33	int slen = strlen(s);
34
35	if (slen >= XT_MAX_COMMENT_LEN) {
36		xtables_error(PARAMETER_PROBLEM,
37			"COMMENT must be shorter than %i characters", XT_MAX_COMMENT_LEN);
38	}
39	strcpy((char *)info->comment, s);
40}
41
42static int
43comment_parse(int c, char **argv, int invert, unsigned int *flags,
44              const void *entry, struct xt_entry_match **match)
45{
46	struct xt_comment_info *commentinfo = (struct xt_comment_info *)(*match)->data;
47
48	switch (c) {
49	case '1':
50		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
51		if (invert) {
52			xtables_error(PARAMETER_PROBLEM,
53					"Sorry, you can't have an inverted comment");
54		}
55		parse_comment(optarg, commentinfo);
56		*flags = 1;
57		break;
58
59	default:
60		return 0;
61	}
62	return 1;
63}
64
65static void comment_check(unsigned int flags)
66{
67	if (!flags)
68		xtables_error(PARAMETER_PROBLEM,
69			   "COMMENT match: You must specify `--comment'");
70}
71
72static void
73comment_print(const void *ip, const struct xt_entry_match *match, int numeric)
74{
75	struct xt_comment_info *commentinfo = (void *)match->data;
76
77	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
78	printf("/* %s */ ", commentinfo->comment);
79}
80
81/* Saves the union ipt_matchinfo in parsable form to stdout. */
82static void
83comment_save(const void *ip, const struct xt_entry_match *match)
84{
85	struct xt_comment_info *commentinfo = (void *)match->data;
86
87	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
88	printf("--comment ");
89	xtables_save_string((const char *)commentinfo->comment);
90}
91
92static struct xtables_match comment_match = {
93	.family		= NFPROTO_UNSPEC,
94	.name		= "comment",
95	.version	= XTABLES_VERSION,
96	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
97	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
98	.help		= comment_help,
99	.parse		= comment_parse,
100	.final_check	= comment_check,
101	.print 		= comment_print,
102	.save 		= comment_save,
103	.extra_opts	= comment_opts,
104};
105
106void _init(void)
107{
108	xtables_register_match(&comment_match);
109}
110