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> |
| 12 | #include <iptables.h> |
| 13 | |
| 14 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 15 | #include <linux/netfilter_ipv4/ipt_ttl.h> |
| 16 | |
| 17 | static void help(void) |
| 18 | { |
| 19 | printf( |
| 20 | "TTL match v%s 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" |
| 23 | " --ttl-gt value Match TTL > value\n" |
Harald Welte | 80fe35d | 2002-05-29 13:08:15 +0000 | [diff] [blame] | 24 | , IPTABLES_VERSION); |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 25 | } |
| 26 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 27 | static int parse(int c, char **argv, int invert, unsigned int *flags, |
| 28 | const struct ipt_entry *entry, unsigned int *nfcache, |
| 29 | struct ipt_entry_match **match) |
| 30 | { |
| 31 | struct ipt_ttl_info *info = (struct ipt_ttl_info *) (*match)->data; |
Harald Welte | efa8fc2 | 2005-07-19 22:03:49 +0000 | [diff] [blame] | 32 | unsigned int value; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 33 | |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 34 | check_inverse(optarg, &invert, &optind, 0); |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 35 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 36 | switch (c) { |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 37 | case '2': |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 38 | if (string_to_number(optarg, 0, 255, &value) == -1) |
| 39 | exit_error(PARAMETER_PROBLEM, |
| 40 | "ttl: Expected value between 0 and 255"); |
| 41 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 42 | if (invert) |
| 43 | info->mode = IPT_TTL_NE; |
| 44 | else |
| 45 | info->mode = IPT_TTL_EQ; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 46 | |
| 47 | /* is 0 allowed? */ |
| 48 | info->ttl = value; |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 49 | break; |
| 50 | case '3': |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 51 | if (string_to_number(optarg, 0, 255, &value) == -1) |
| 52 | exit_error(PARAMETER_PROBLEM, |
| 53 | "ttl: Expected value between 0 and 255"); |
| 54 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 55 | if (invert) |
| 56 | exit_error(PARAMETER_PROBLEM, |
| 57 | "ttl: unexpected `!'"); |
| 58 | |
| 59 | info->mode = IPT_TTL_LT; |
| 60 | info->ttl = value; |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 61 | break; |
| 62 | case '4': |
Patrick McHardy | 6656e13 | 2005-11-18 17:59:56 +0000 | [diff] [blame] | 63 | if (string_to_number(optarg, 0, 255, &value) == -1) |
| 64 | exit_error(PARAMETER_PROBLEM, |
| 65 | "ttl: Expected value between 0 and 255"); |
| 66 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 67 | if (invert) |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 68 | exit_error(PARAMETER_PROBLEM, |
| 69 | "ttl: unexpected `!'"); |
| 70 | |
| 71 | info->mode = IPT_TTL_GT; |
| 72 | info->ttl = value; |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 73 | break; |
| 74 | default: |
| 75 | return 0; |
| 76 | |
| 77 | } |
| 78 | |
Phil Oester | 7defa34 | 2004-08-23 20:45:17 +0000 | [diff] [blame] | 79 | if (*flags) |
| 80 | exit_error(PARAMETER_PROBLEM, |
| 81 | "Can't specify TTL option twice"); |
| 82 | *flags = 1; |
| 83 | |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 84 | return 1; |
| 85 | } |
| 86 | |
| 87 | static void final_check(unsigned int flags) |
| 88 | { |
| 89 | if (!flags) |
| 90 | exit_error(PARAMETER_PROBLEM, |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 91 | "TTL match: You must specify one of " |
| 92 | "`--ttl-eq', `--ttl-lt', `--ttl-gt"); |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 93 | } |
| 94 | |
| 95 | static void print(const struct ipt_ip *ip, |
| 96 | const struct ipt_entry_match *match, |
| 97 | int numeric) |
| 98 | { |
| 99 | const struct ipt_ttl_info *info = |
| 100 | (struct ipt_ttl_info *) match->data; |
| 101 | |
| 102 | printf("TTL match "); |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 103 | switch (info->mode) { |
| 104 | case IPT_TTL_EQ: |
| 105 | printf("TTL == "); |
| 106 | break; |
| 107 | case IPT_TTL_NE: |
| 108 | printf("TTL != "); |
| 109 | break; |
| 110 | case IPT_TTL_LT: |
| 111 | printf("TTL < "); |
| 112 | break; |
| 113 | case IPT_TTL_GT: |
| 114 | printf("TTL > "); |
| 115 | break; |
| 116 | } |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 117 | printf("%u ", info->ttl); |
| 118 | } |
| 119 | |
| 120 | static void save(const struct ipt_ip *ip, |
| 121 | const struct ipt_entry_match *match) |
| 122 | { |
| 123 | const struct ipt_ttl_info *info = |
| 124 | (struct ipt_ttl_info *) match->data; |
| 125 | |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 126 | switch (info->mode) { |
| 127 | case IPT_TTL_EQ: |
| 128 | printf("--ttl-eq "); |
| 129 | break; |
| 130 | case IPT_TTL_NE: |
| 131 | printf("! --ttl-eq "); |
| 132 | break; |
| 133 | case IPT_TTL_LT: |
| 134 | printf("--ttl-lt "); |
| 135 | break; |
| 136 | case IPT_TTL_GT: |
| 137 | printf("--ttl-gt "); |
| 138 | break; |
| 139 | default: |
| 140 | /* error */ |
| 141 | break; |
| 142 | } |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 143 | printf("%u ", info->ttl); |
| 144 | } |
| 145 | |
| 146 | static struct option opts[] = { |
Harald Welte | 1441c42 | 2000-11-13 12:32:50 +0000 | [diff] [blame] | 147 | { "ttl", 1, 0, '2' }, |
| 148 | { "ttl-eq", 1, 0, '2'}, |
| 149 | { "ttl-lt", 1, 0, '3'}, |
| 150 | { "ttl-gt", 1, 0, '4'}, |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 151 | { 0 } |
| 152 | }; |
| 153 | |
Pablo Neira | 8caee8b | 2004-12-28 13:11:59 +0000 | [diff] [blame] | 154 | static struct iptables_match ttl = { |
| 155 | .next = NULL, |
| 156 | .name = "ttl", |
| 157 | .version = IPTABLES_VERSION, |
| 158 | .size = IPT_ALIGN(sizeof(struct ipt_ttl_info)), |
| 159 | .userspacesize = IPT_ALIGN(sizeof(struct ipt_ttl_info)), |
| 160 | .help = &help, |
Pablo Neira | 8caee8b | 2004-12-28 13:11:59 +0000 | [diff] [blame] | 161 | .parse = &parse, |
| 162 | .final_check = &final_check, |
| 163 | .print = &print, |
| 164 | .save = &save, |
| 165 | .extra_opts = opts |
Harald Welte | 703828f | 2000-10-04 15:27:07 +0000 | [diff] [blame] | 166 | }; |
| 167 | |
| 168 | |
| 169 | void _init(void) |
| 170 | { |
| 171 | register_match(&ttl); |
| 172 | } |