1 /* Shared library add-on to iptables to add TTL matching support
2 * (C) 2000 by Harald Welte <laforge@gnumonks.org>
6 * This program is released under the terms of GNU GPL */
14 #include <linux/netfilter_ipv4/ipt_ttl.h>
16 static void ttl_help(void)
19 "ttl match options:\n"
20 " --ttl-eq value Match time to live value\n"
21 " --ttl-lt value Match TTL < value\n"
22 " --ttl-gt value Match TTL > value\n");
25 static int ttl_parse(int c, char **argv, int invert, unsigned int *flags,
26 const void *entry, struct xt_entry_match **match)
28 struct ipt_ttl_info *info = (struct ipt_ttl_info *) (*match)->data;
31 xtables_check_inverse(optarg, &invert, &optind, 0, argv);
35 if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
36 xtables_error(PARAMETER_PROBLEM,
37 "ttl: Expected value between 0 and 255");
40 info->mode = IPT_TTL_NE;
42 info->mode = IPT_TTL_EQ;
48 if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
49 xtables_error(PARAMETER_PROBLEM,
50 "ttl: Expected value between 0 and 255");
53 xtables_error(PARAMETER_PROBLEM,
54 "ttl: unexpected `!'");
56 info->mode = IPT_TTL_LT;
60 if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
61 xtables_error(PARAMETER_PROBLEM,
62 "ttl: Expected value between 0 and 255");
65 xtables_error(PARAMETER_PROBLEM,
66 "ttl: unexpected `!'");
68 info->mode = IPT_TTL_GT;
77 xtables_error(PARAMETER_PROBLEM,
78 "Can't specify TTL option twice");
84 static void ttl_check(unsigned int flags)
87 xtables_error(PARAMETER_PROBLEM,
88 "TTL match: You must specify one of "
89 "`--ttl-eq', `--ttl-lt', `--ttl-gt");
92 static void ttl_print(const void *ip, const struct xt_entry_match *match,
95 const struct ipt_ttl_info *info =
96 (struct ipt_ttl_info *) match->data;
113 printf("%u ", info->ttl);
116 static void ttl_save(const void *ip, const struct xt_entry_match *match)
118 const struct ipt_ttl_info *info =
119 (struct ipt_ttl_info *) match->data;
121 switch (info->mode) {
126 printf("! --ttl-eq ");
138 printf("%u ", info->ttl);
141 static const struct option ttl_opts[] = {
142 { "ttl", 1, NULL, '2' },
143 { "ttl-eq", 1, NULL, '2'},
144 { "ttl-lt", 1, NULL, '3'},
145 { "ttl-gt", 1, NULL, '4'},
149 static struct xtables_match ttl_mt_reg = {
151 .version = XTABLES_VERSION,
152 .family = NFPROTO_IPV4,
153 .size = XT_ALIGN(sizeof(struct ipt_ttl_info)),
154 .userspacesize = XT_ALIGN(sizeof(struct ipt_ttl_info)),
157 .final_check = ttl_check,
160 .extra_opts = ttl_opts,
166 xtables_register_match(&ttl_mt_reg);