Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add TTL matching support |
| 2 | * (C) 2000 by Harald Welte <laforge@gnumonks.org> |
| 3 | * |
Rusty Russell | 70f758d | 2004-12-22 04:26:53 +0000 | [diff] [blame] | 4 | * $Id$ |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 5 | * |
| 6 | * This program is released under the terms of GNU GPL */ |
| 7 | |
| 8 | #include <stdio.h> |
| 9 | #include <stdlib.h> |
| 10 | #include <string.h> |
| 11 | #include <getopt.h> |
Jan Engelhardt | 5d9678a | 2008-11-20 10:15:35 +0100 | [diff] [blame] | 12 | #include <xtables.h> |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 13 | |
| 14 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 15 | #include <linux/netfilter_ipv4/ipt_ttl.h> |
| 16 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 17 | static void ttl_help(void) |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 18 | { |
| 19 | printf( |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 20 | "ttl match options:\n" |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 21 | " --ttl-eq value Match time to live value\n" |
| 22 | " --ttl-lt value Match TTL < value\n" |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 23 | " --ttl-gt value Match TTL > value\n"); |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 24 | } |
| 25 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 26 | static int ttl_parse(int c, char **argv, int invert, unsigned int *flags, |
| 27 | const void *entry, struct xt_entry_match **match) |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 28 | { |
| 29 | struct ipt_ttl_info *info = (struct ipt_ttl_info *) (*match)->data; |
Harald Welte | efa8fc2 | 2005-07-19 22:03:49 +0000 | [diff] [blame] | 30 | unsigned int value; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 31 | |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 32 | check_inverse(optarg, &invert, &optind, 0); |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 33 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 34 | switch (c) { |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 35 | case '2': |
Jan Engelhardt | 5f2922c | 2009-01-27 18:43:01 +0100 | [diff] [blame] | 36 | if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX)) |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 37 | exit_error(PARAMETER_PROBLEM, |
| 38 | "ttl: Expected value between 0 and 255"); |
| 39 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 40 | if (invert) |
| 41 | info->mode = IPT_TTL_NE; |
| 42 | else |
| 43 | info->mode = IPT_TTL_EQ; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 44 | |
| 45 | /* is 0 allowed? */ |
| 46 | info->ttl = value; |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 47 | break; |
| 48 | case '3': |
Jan Engelhardt | 5f2922c | 2009-01-27 18:43:01 +0100 | [diff] [blame] | 49 | if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX)) |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 50 | exit_error(PARAMETER_PROBLEM, |
| 51 | "ttl: Expected value between 0 and 255"); |
| 52 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 53 | if (invert) |
| 54 | exit_error(PARAMETER_PROBLEM, |
| 55 | "ttl: unexpected `!'"); |
| 56 | |
| 57 | info->mode = IPT_TTL_LT; |
| 58 | info->ttl = value; |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 59 | break; |
| 60 | case '4': |
Jan Engelhardt | 5f2922c | 2009-01-27 18:43:01 +0100 | [diff] [blame] | 61 | if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX)) |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 62 | exit_error(PARAMETER_PROBLEM, |
| 63 | "ttl: Expected value between 0 and 255"); |
| 64 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 65 | if (invert) |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 66 | exit_error(PARAMETER_PROBLEM, |
| 67 | "ttl: unexpected `!'"); |
| 68 | |
| 69 | info->mode = IPT_TTL_GT; |
| 70 | info->ttl = value; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 71 | break; |
| 72 | default: |
| 73 | return 0; |
| 74 | |
| 75 | } |
| 76 | |
Phil Oester | 7defa34 | 2004-08-23 20:45:17 +0000 | [diff] [blame] | 77 | if (*flags) |
| 78 | exit_error(PARAMETER_PROBLEM, |
| 79 | "Can't specify TTL option twice"); |
| 80 | *flags = 1; |
| 81 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 82 | return 1; |
| 83 | } |
| 84 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 85 | static void ttl_check(unsigned int flags) |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 86 | { |
| 87 | if (!flags) |
| 88 | exit_error(PARAMETER_PROBLEM, |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 89 | "TTL match: You must specify one of " |
| 90 | "`--ttl-eq', `--ttl-lt', `--ttl-gt"); |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 91 | } |
| 92 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 93 | static void ttl_print(const void *ip, const struct xt_entry_match *match, |
| 94 | int numeric) |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 95 | { |
| 96 | const struct ipt_ttl_info *info = |
| 97 | (struct ipt_ttl_info *) match->data; |
| 98 | |
| 99 | printf("TTL match "); |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 100 | switch (info->mode) { |
| 101 | case IPT_TTL_EQ: |
| 102 | printf("TTL == "); |
| 103 | break; |
| 104 | case IPT_TTL_NE: |
| 105 | printf("TTL != "); |
| 106 | break; |
| 107 | case IPT_TTL_LT: |
| 108 | printf("TTL < "); |
| 109 | break; |
| 110 | case IPT_TTL_GT: |
| 111 | printf("TTL > "); |
| 112 | break; |
| 113 | } |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 114 | printf("%u ", info->ttl); |
| 115 | } |
| 116 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 117 | static void ttl_save(const void *ip, const struct xt_entry_match *match) |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 118 | { |
| 119 | const struct ipt_ttl_info *info = |
| 120 | (struct ipt_ttl_info *) match->data; |
| 121 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 122 | switch (info->mode) { |
| 123 | case IPT_TTL_EQ: |
| 124 | printf("--ttl-eq "); |
| 125 | break; |
| 126 | case IPT_TTL_NE: |
| 127 | printf("! --ttl-eq "); |
| 128 | break; |
| 129 | case IPT_TTL_LT: |
| 130 | printf("--ttl-lt "); |
| 131 | break; |
| 132 | case IPT_TTL_GT: |
| 133 | printf("--ttl-gt "); |
| 134 | break; |
| 135 | default: |
| 136 | /* error */ |
| 137 | break; |
| 138 | } |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 139 | printf("%u ", info->ttl); |
| 140 | } |
| 141 | |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 142 | static const struct option ttl_opts[] = { |
Patrick McHardy | 500f483 | 2007-09-08 15:59:04 +0000 | [diff] [blame] | 143 | { "ttl", 1, NULL, '2' }, |
| 144 | { "ttl-eq", 1, NULL, '2'}, |
| 145 | { "ttl-lt", 1, NULL, '3'}, |
| 146 | { "ttl-gt", 1, NULL, '4'}, |
Max Kellermann | 9ee386a | 2008-01-29 13:48:05 +0000 | [diff] [blame] | 147 | { .name = NULL } |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 148 | }; |
| 149 | |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 150 | static struct xtables_match ttl_mt_reg = { |
Pablo Neira | 8caee8b | 2004-12-28 13:11:59 +0000 | [diff] [blame] | 151 | .name = "ttl", |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 152 | .version = XTABLES_VERSION, |
Jan Engelhardt | 03d9948 | 2008-11-18 12:27:54 +0100 | [diff] [blame] | 153 | .family = NFPROTO_IPV4, |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 154 | .size = XT_ALIGN(sizeof(struct ipt_ttl_info)), |
| 155 | .userspacesize = XT_ALIGN(sizeof(struct ipt_ttl_info)), |
Jan Engelhardt | 59d1640 | 2007-10-04 16:28:39 +0000 | [diff] [blame] | 156 | .help = ttl_help, |
| 157 | .parse = ttl_parse, |
| 158 | .final_check = ttl_check, |
| 159 | .print = ttl_print, |
| 160 | .save = ttl_save, |
| 161 | .extra_opts = ttl_opts, |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 162 | }; |
| 163 | |
| 164 | |
| 165 | void _init(void) |
| 166 | { |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 167 | xtables_register_match(&ttl_mt_reg); |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 168 | } |