libxt_comment.c revision 8b7c64d6ba156a99008fcd810cba874c73294333 
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 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	{ "comment", 1, NULL, '1' },
27	{ .name = NULL }
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		exit_error(PARAMETER_PROBLEM,
37			"COMMENT must be shorter than %i characters", XT_MAX_COMMENT_LEN);
38	}
39	strcpy((char *)info->comment, s);
40}
41
42/* Function which parses command options; returns true if it
43   ate an option */
44static int
45comment_parse(int c, char **argv, int invert, unsigned int *flags,
46              const void *entry, struct xt_entry_match **match)
47{
48	struct xt_comment_info *commentinfo = (struct xt_comment_info *)(*match)->data;
49
50	switch (c) {
51	case '1':
52		check_inverse(argv[optind-1], &invert, &optind, 0);
53		if (invert) {
54			exit_error(PARAMETER_PROBLEM,
55					"Sorry, you can't have an inverted comment");
56		}
57		parse_comment(argv[optind-1], commentinfo);
58		*flags = 1;
59		break;
60
61	default:
62		return 0;
63	}
64	return 1;
65}
66
67/* Final check; must have specified --comment. */
68static void comment_check(unsigned int flags)
69{
70	if (!flags)
71		exit_error(PARAMETER_PROBLEM,
72			   "COMMENT match: You must specify `--comment'");
73}
74
75/* Prints out the matchinfo. */
76static void
77comment_print(const void *ip, const struct xt_entry_match *match, int numeric)
78{
79	struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
80
81	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
82	printf("/* %s */ ", commentinfo->comment);
83}
84
85/* Saves the union ipt_matchinfo in parsable form to stdout. */
86static void
87comment_save(const void *ip, const struct xt_entry_match *match)
88{
89	struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
90
91	commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
92	printf("--comment \"%s\" ", commentinfo->comment);
93}
94
95static struct xtables_match comment_match = {
96	.family		= AF_INET,
97	.name		= "comment",
98	.version	= XTABLES_VERSION,
99	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
100	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
101	.help		= comment_help,
102	.parse		= comment_parse,
103	.final_check	= comment_check,
104	.print 		= comment_print,
105	.save 		= comment_save,
106	.extra_opts	= comment_opts,
107};
108
109static struct xtables_match comment_match6 = {
110	.family		= AF_INET6,
111	.name		= "comment",
112	.version	= XTABLES_VERSION,
113	.size		= XT_ALIGN(sizeof(struct xt_comment_info)),
114	.userspacesize	= XT_ALIGN(sizeof(struct xt_comment_info)),
115	.help		= comment_help,
116	.parse		= comment_parse,
117	.final_check	= comment_check,
118	.print 		= comment_print,
119	.save 		= comment_save,
120	.extra_opts	= comment_opts,
121};
122
123void _init(void)
124{
125	xtables_register_match(&comment_match);
126	xtables_register_match(&comment_match6);
127}
128