1/* Shared library add-on to iptables to add limit support. 2 * 3 * J�r�me de Vivie <devivie@info.enserb.u-bordeaux.fr> 4 * Herv� Eychenne <rv@wallfire.org> 5 */ 6 7#include <stdio.h> 8#include <string.h> 9#include <stdlib.h> 10#include <getopt.h> 11#include <iptables.h> 12#include <stddef.h> 13#include <linux/netfilter_ipv4/ip_tables.h> 14/* For 64bit kernel / 32bit userspace */ 15#include "../include/linux/netfilter_ipv4/ipt_limit.h" 16 17#define IPT_LIMIT_AVG "3/hour" 18#define IPT_LIMIT_BURST 5 19 20/* Function which prints out usage message. */ 21static void 22help(void) 23{ 24 printf( 25"limit v%s options:\n" 26"--limit avg max average match rate: default "IPT_LIMIT_AVG"\n" 27" [Packets per second unless followed by \n" 28" /sec /minute /hour /day postfixes]\n" 29"--limit-burst number number to match in a burst, default %u\n" 30"\n", IPTABLES_VERSION, IPT_LIMIT_BURST); 31} 32 33static struct option opts[] = { 34 { "limit", 1, 0, '%' }, 35 { "limit-burst", 1, 0, '$' }, 36 { 0 } 37}; 38 39static 40int parse_rate(const char *rate, u_int32_t *val) 41{ 42 const char *delim; 43 u_int32_t r; 44 u_int32_t mult = 1; /* Seconds by default. */ 45 46 delim = strchr(rate, '/'); 47 if (delim) { 48 if (strlen(delim+1) == 0) 49 return 0; 50 51 if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0) 52 mult = 1; 53 else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0) 54 mult = 60; 55 else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0) 56 mult = 60*60; 57 else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0) 58 mult = 24*60*60; 59 else 60 return 0; 61 } 62 r = atoi(rate); 63 if (!r) 64 return 0; 65 66 /* This would get mapped to infinite (1/day is minimum they 67 can specify, so we're ok at that end). */ 68 if (r / mult > IPT_LIMIT_SCALE) 69 exit_error(PARAMETER_PROBLEM, "Rate too fast `%s'\n", rate); 70 71 *val = IPT_LIMIT_SCALE * mult / r; 72 return 1; 73} 74 75/* Initialize the match. */ 76static void 77init(struct ipt_entry_match *m, unsigned int *nfcache) 78{ 79 struct ipt_rateinfo *r = (struct ipt_rateinfo *)m->data; 80 81 parse_rate(IPT_LIMIT_AVG, &r->avg); 82 r->burst = IPT_LIMIT_BURST; 83 84} 85 86 87/* Function which parses command options; returns true if it 88 ate an option */ 89static int 90parse(int c, char **argv, int invert, unsigned int *flags, 91 const struct ipt_entry *entry, 92 unsigned int *nfcache, 93 struct ipt_entry_match **match) 94{ 95 struct ipt_rateinfo *r = (struct ipt_rateinfo *)(*match)->data; 96 unsigned int num; 97 98 switch(c) { 99 case '%': 100 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break; 101 if (!parse_rate(optarg, &r->avg)) 102 exit_error(PARAMETER_PROBLEM, 103 "bad rate `%s'", optarg); 104 break; 105 106 case '$': 107 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break; 108 if (string_to_number(optarg, 0, 10000, &num) == -1) 109 exit_error(PARAMETER_PROBLEM, 110 "bad --limit-burst `%s'", optarg); 111 r->burst = num; 112 break; 113 114 default: 115 return 0; 116 } 117 118 if (invert) 119 exit_error(PARAMETER_PROBLEM, 120 "limit does not support invert"); 121 122 return 1; 123} 124 125/* Final check; nothing. */ 126static void final_check(unsigned int flags) 127{ 128} 129 130static struct rates 131{ 132 const char *name; 133 u_int32_t mult; 134} rates[] = { { "day", IPT_LIMIT_SCALE*24*60*60 }, 135 { "hour", IPT_LIMIT_SCALE*60*60 }, 136 { "min", IPT_LIMIT_SCALE*60 }, 137 { "sec", IPT_LIMIT_SCALE } }; 138 139static void print_rate(u_int32_t period) 140{ 141 unsigned int i; 142 143 for (i = 1; i < sizeof(rates)/sizeof(struct rates); i++) { 144 if (period > rates[i].mult 145 || rates[i].mult/period < rates[i].mult%period) 146 break; 147 } 148 149 printf("%u/%s ", rates[i-1].mult / period, rates[i-1].name); 150} 151 152/* Prints out the matchinfo. */ 153static void 154print(const struct ipt_ip *ip, 155 const struct ipt_entry_match *match, 156 int numeric) 157{ 158 struct ipt_rateinfo *r = (struct ipt_rateinfo *)match->data; 159 printf("limit: avg "); print_rate(r->avg); 160 printf("burst %u ", r->burst); 161} 162 163static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match) 164{ 165 struct ipt_rateinfo *r = (struct ipt_rateinfo *)match->data; 166 167 printf("--limit "); print_rate(r->avg); 168 if (r->burst != IPT_LIMIT_BURST) 169 printf("--limit-burst %u ", r->burst); 170} 171 172static struct iptables_match limit = { 173 .next = NULL, 174 .name = "limit", 175 .version = IPTABLES_VERSION, 176 .size = IPT_ALIGN(sizeof(struct ipt_rateinfo)), 177 .userspacesize = offsetof(struct ipt_rateinfo, prev), 178 .help = &help, 179 .init = &init, 180 .parse = &parse, 181 .final_check = &final_check, 182 .print = &print, 183 .save = &save, 184 .extra_opts = opts 185}; 186 187void _init(void) 188{ 189 register_match(&limit); 190} 191