1/* Shared library add-on to iptables to add recent matching support. */ 2#include <stdio.h> 3#include <netdb.h> 4#include <string.h> 5#include <stdlib.h> 6#include <getopt.h> 7 8#include <iptables.h> 9#include <linux/netfilter_ipv4/ipt_recent.h> 10 11/* Need these in order to not fail when compiling against an older kernel. */ 12#ifndef RECENT_NAME 13#define RECENT_NAME "ipt_recent" 14#endif /* RECENT_NAME */ 15 16#ifndef RECENT_VER 17#define RECENT_VER "unknown" 18#endif /* RECENT_VER */ 19 20#ifndef IPT_RECENT_NAME_LEN 21#define IPT_RECENT_NAME_LEN 200 22#endif /* IPT_RECENT_NAME_LEN */ 23 24/* Options for this module */ 25static struct option opts[] = { 26 { .name = "set", .has_arg = 0, .flag = 0, .val = 201 }, 27 { .name = "rcheck", .has_arg = 0, .flag = 0, .val = 202 }, 28 { .name = "update", .has_arg = 0, .flag = 0, .val = 203 }, 29 { .name = "seconds", .has_arg = 1, .flag = 0, .val = 204 }, 30 { .name = "hitcount", .has_arg = 1, .flag = 0, .val = 205 }, 31 { .name = "remove", .has_arg = 0, .flag = 0, .val = 206 }, 32 { .name = "rttl", .has_arg = 0, .flag = 0, .val = 207 }, 33 { .name = "name", .has_arg = 1, .flag = 0, .val = 208 }, 34 { .name = "rsource", .has_arg = 0, .flag = 0, .val = 209 }, 35 { .name = "rdest", .has_arg = 0, .flag = 0, .val = 210 }, 36 { .name = 0, .has_arg = 0, .flag = 0, .val = 0 } 37}; 38 39/* Function which prints out usage message. */ 40static void 41help(void) 42{ 43 printf( 44"recent v%s options:\n" 45"[!] --set Add source address to list, always matches.\n" 46"[!] --rcheck Match if source address in list.\n" 47"[!] --update Match if source address in list, also update last-seen time.\n" 48"[!] --remove Match if source address in list, also removes that address from list.\n" 49" --seconds seconds For check and update commands above.\n" 50" Specifies that the match will only occur if source address last seen within\n" 51" the last 'seconds' seconds.\n" 52" --hitcount hits For check and update commands above.\n" 53" Specifies that the match will only occur if source address seen hits times.\n" 54" May be used in conjunction with the seconds option.\n" 55" --rttl For check and update commands above.\n" 56" Specifies that the match will only occur if the source address and the TTL\n" 57" match between this packet and the one which was set.\n" 58" Useful if you have problems with people spoofing their source address in order\n" 59" to DoS you via this module.\n" 60" --name name Name of the recent list to be used. DEFAULT used if none given.\n" 61" --rsource Match/Save the source address of each packet in the recent list table (default).\n" 62" --rdest Match/Save the destination address of each packet in the recent list table.\n" 63RECENT_NAME " " RECENT_VER ": Stephen Frost <sfrost@snowman.net>. http://snowman.net/projects/ipt_recent/\n" 64, 65IPTABLES_VERSION); 66 67} 68 69/* Initialize the match. */ 70static void 71init(struct ipt_entry_match *match, unsigned int *nfcache) 72{ 73 struct ipt_recent_info *info = (struct ipt_recent_info *)(match)->data; 74 75 76 strncpy(info->name,"DEFAULT",IPT_RECENT_NAME_LEN); 77 /* eventhough IPT_RECENT_NAME_LEN is currently defined as 200, 78 * better be safe, than sorry */ 79 info->name[IPT_RECENT_NAME_LEN-1] = '\0'; 80 info->side = IPT_RECENT_SOURCE; 81} 82 83/* Function which parses command options; returns true if it 84 ate an option */ 85static int 86parse(int c, char **argv, int invert, unsigned int *flags, 87 const struct ipt_entry *entry, 88 unsigned int *nfcache, 89 struct ipt_entry_match **match) 90{ 91 struct ipt_recent_info *info = (struct ipt_recent_info *)(*match)->data; 92 switch (c) { 93 case 201: 94 if (*flags) exit_error(PARAMETER_PROBLEM, 95 "recent: only one of `--set', `--rcheck' " 96 "`--update' or `--remove' may be set"); 97 check_inverse(optarg, &invert, &optind, 0); 98 info->check_set |= IPT_RECENT_SET; 99 if (invert) info->invert = 1; 100 *flags = 1; 101 break; 102 103 case 202: 104 if (*flags) exit_error(PARAMETER_PROBLEM, 105 "recent: only one of `--set', `--rcheck' " 106 "`--update' or `--remove' may be set"); 107 check_inverse(optarg, &invert, &optind, 0); 108 info->check_set |= IPT_RECENT_CHECK; 109 if(invert) info->invert = 1; 110 *flags = 1; 111 break; 112 113 case 203: 114 if (*flags) exit_error(PARAMETER_PROBLEM, 115 "recent: only one of `--set', `--rcheck' " 116 "`--update' or `--remove' may be set"); 117 check_inverse(optarg, &invert, &optind, 0); 118 info->check_set |= IPT_RECENT_UPDATE; 119 if (invert) info->invert = 1; 120 *flags = 1; 121 break; 122 123 case 206: 124 if (*flags) exit_error(PARAMETER_PROBLEM, 125 "recent: only one of `--set', `--rcheck' " 126 "`--update' or `--remove' may be set"); 127 check_inverse(optarg, &invert, &optind, 0); 128 info->check_set |= IPT_RECENT_REMOVE; 129 if (invert) info->invert = 1; 130 *flags = 1; 131 break; 132 133 case 204: 134 info->seconds = atoi(optarg); 135 break; 136 137 case 205: 138 info->hit_count = atoi(optarg); 139 break; 140 141 case 207: 142 info->check_set |= IPT_RECENT_TTL; 143 break; 144 145 case 208: 146 strncpy(info->name,optarg,IPT_RECENT_NAME_LEN); 147 info->name[IPT_RECENT_NAME_LEN-1] = '\0'; 148 break; 149 150 case 209: 151 info->side = IPT_RECENT_SOURCE; 152 break; 153 154 case 210: 155 info->side = IPT_RECENT_DEST; 156 break; 157 158 default: 159 return 0; 160 } 161 162 return 1; 163} 164 165/* Final check; must have specified a specific option. */ 166static void 167final_check(unsigned int flags) 168{ 169 170 if (!flags) 171 exit_error(PARAMETER_PROBLEM, 172 "recent: you must specify one of `--set', `--rcheck' " 173 "`--update' or `--remove'"); 174} 175 176/* Prints out the matchinfo. */ 177static void 178print(const struct ipt_ip *ip, 179 const struct ipt_entry_match *match, 180 int numeric) 181{ 182 struct ipt_recent_info *info = (struct ipt_recent_info *)match->data; 183 184 if (info->invert) 185 fputc('!', stdout); 186 187 printf("recent: "); 188 if(info->check_set & IPT_RECENT_SET) printf("SET "); 189 if(info->check_set & IPT_RECENT_CHECK) printf("CHECK "); 190 if(info->check_set & IPT_RECENT_UPDATE) printf("UPDATE "); 191 if(info->check_set & IPT_RECENT_REMOVE) printf("REMOVE "); 192 if(info->seconds) printf("seconds: %d ",info->seconds); 193 if(info->hit_count) printf("hit_count: %d ",info->hit_count); 194 if(info->check_set & IPT_RECENT_TTL) printf("TTL-Match "); 195 if(info->name) printf("name: %s ",info->name); 196 if(info->side == IPT_RECENT_SOURCE) printf("side: source "); 197 if(info->side == IPT_RECENT_DEST) printf("side: dest"); 198} 199 200/* Saves the union ipt_matchinfo in parsable form to stdout. */ 201static void 202save(const struct ipt_ip *ip, const struct ipt_entry_match *match) 203{ 204 struct ipt_recent_info *info = (struct ipt_recent_info *)match->data; 205 206 if (info->invert) 207 printf("! "); 208 209 if(info->check_set & IPT_RECENT_SET) printf("--set "); 210 if(info->check_set & IPT_RECENT_CHECK) printf("--rcheck "); 211 if(info->check_set & IPT_RECENT_UPDATE) printf("--update "); 212 if(info->check_set & IPT_RECENT_REMOVE) printf("--remove "); 213 if(info->seconds) printf("--seconds %d ",info->seconds); 214 if(info->hit_count) printf("--hitcount %d ",info->hit_count); 215 if(info->check_set & IPT_RECENT_TTL) printf("--rttl "); 216 if(info->name) printf("--name %s ",info->name); 217 if(info->side == IPT_RECENT_SOURCE) printf("--rsource "); 218 if(info->side == IPT_RECENT_DEST) printf("--rdest "); 219} 220 221/* Structure for iptables to use to communicate with module */ 222static struct iptables_match recent = { 223 .next = NULL, 224 .name = "recent", 225 .version = IPTABLES_VERSION, 226 .size = IPT_ALIGN(sizeof(struct ipt_recent_info)), 227 .userspacesize = IPT_ALIGN(sizeof(struct ipt_recent_info)), 228 .help = &help, 229 .init = &init, 230 .parse = &parse, 231 .final_check = &final_check, 232 .print = &print, 233 .save = &save, 234 .extra_opts = opts 235}; 236 237void _init(void) 238{ 239 register_match(&recent); 240} 241