Marc Boucher | e6869a8 | 2000-03-20 06:03:29 +0000 | [diff] [blame^] | 1 | /* Shared library add-on to iptables to add limit support. |
| 2 | * |
| 3 | * Jérôme de Vivie <devivie@info.enserb.u-bordeaux.fr> |
| 4 | * Hervé Eychenne <eychenne@info.enserb.u-bordeaux.fr> |
| 5 | */ |
| 6 | #include <stdio.h> |
| 7 | #include <string.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <getopt.h> |
| 10 | #include <iptables.h> |
| 11 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 12 | #include <linux/netfilter_ipv4/ipt_limit.h> |
| 13 | |
| 14 | #define IPT_LIMIT_AVG "3/hour" |
| 15 | #define IPT_LIMIT_BURST 5 |
| 16 | |
| 17 | /* Function which prints out usage message. */ |
| 18 | static void |
| 19 | help(void) |
| 20 | { |
| 21 | printf( |
| 22 | "limit v%s options:\n" |
| 23 | "--limit avg max average match rate: default "IPT_LIMIT_AVG"\n" |
| 24 | " [Packets per second unless followed by \n" |
| 25 | " /sec /minute /hour /day postfixes]\n" |
| 26 | "--limit-burst number number to match in a burst, default %u\n" |
| 27 | "\n", NETFILTER_VERSION, IPT_LIMIT_BURST); |
| 28 | } |
| 29 | |
| 30 | static struct option opts[] = { |
| 31 | { "limit", 1, 0, '%' }, |
| 32 | { "limit-burst", 1, 0, '$' }, |
| 33 | { 0 } |
| 34 | }; |
| 35 | |
| 36 | static |
| 37 | int parse_rate(const char *rate, u_int32_t *val) |
| 38 | { |
| 39 | const char *delim; |
| 40 | u_int32_t r; |
| 41 | u_int32_t mult = 1; /* Seconds by default. */ |
| 42 | |
| 43 | delim = strchr(rate, '/'); |
| 44 | if (delim) { |
| 45 | if (strlen(delim+1) == 0) |
| 46 | return 0; |
| 47 | |
| 48 | if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0) |
| 49 | mult = 1; |
| 50 | else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0) |
| 51 | mult = 60; |
| 52 | else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0) |
| 53 | mult = 60*60; |
| 54 | else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0) |
| 55 | mult = 24*60*60; |
| 56 | else |
| 57 | return 0; |
| 58 | } |
| 59 | r = atoi(rate); |
| 60 | if (!r) |
| 61 | return 0; |
| 62 | |
| 63 | /* This would get mapped to infinite (1/day is minimum they |
| 64 | can specify, so we're ok at that end). */ |
| 65 | if (r / mult > IPT_LIMIT_SCALE) |
| 66 | exit_error(PARAMETER_PROBLEM, "Rate too fast `%s'\n", rate); |
| 67 | |
| 68 | *val = IPT_LIMIT_SCALE * mult / r; |
| 69 | return 1; |
| 70 | } |
| 71 | |
| 72 | /* Initialize the match. */ |
| 73 | static void |
| 74 | init(struct ipt_entry_match *m, unsigned int *nfcache) |
| 75 | { |
| 76 | struct ipt_rateinfo *r = (struct ipt_rateinfo *)m->data; |
| 77 | |
| 78 | parse_rate(IPT_LIMIT_AVG, &r->avg); |
| 79 | r->burst = IPT_LIMIT_BURST; |
| 80 | |
| 81 | /* Can't cache this */ |
| 82 | *nfcache |= NFC_UNKNOWN; |
| 83 | } |
| 84 | |
| 85 | /* FIXME: handle overflow: |
| 86 | if (r->avg*r->burst/r->burst != r->avg) |
| 87 | exit_error(PARAMETER_PROBLEM, |
| 88 | "Sorry: burst too large for that avg rate.\n"); |
| 89 | */ |
| 90 | |
| 91 | /* Function which parses command options; returns true if it |
| 92 | ate an option */ |
| 93 | static int |
| 94 | parse(int c, char **argv, int invert, unsigned int *flags, |
| 95 | const struct ipt_entry *entry, |
| 96 | unsigned int *nfcache, |
| 97 | struct ipt_entry_match **match) |
| 98 | { |
| 99 | struct ipt_rateinfo *r = (struct ipt_rateinfo *)(*match)->data; |
| 100 | int num; |
| 101 | |
| 102 | switch(c) { |
| 103 | case '%': |
| 104 | if (check_inverse(optarg, &invert)) |
| 105 | exit_error(PARAMETER_PROBLEM, |
| 106 | "Unexpected `!' after --limit"); |
| 107 | if (!parse_rate(optarg, &r->avg)) |
| 108 | exit_error(PARAMETER_PROBLEM, |
| 109 | "bad rate `%s'", optarg); |
| 110 | break; |
| 111 | |
| 112 | case '$': |
| 113 | if (check_inverse(optarg, &invert)) |
| 114 | exit_error(PARAMETER_PROBLEM, |
| 115 | "Unexpected `!' after --limit-burst"); |
| 116 | |
| 117 | num = string_to_number(optarg, 0, 10000); |
| 118 | if (num <= 0) |
| 119 | exit_error(PARAMETER_PROBLEM, |
| 120 | "bad --limit-burst `%s'", optarg); |
| 121 | r->burst = num; |
| 122 | break; |
| 123 | |
| 124 | default: |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | return 1; |
| 129 | } |
| 130 | |
| 131 | /* Final check; nothing. */ |
| 132 | static void final_check(unsigned int flags) |
| 133 | { |
| 134 | } |
| 135 | |
| 136 | static struct rates |
| 137 | { |
| 138 | const char *name; |
| 139 | u_int32_t mult; |
| 140 | } rates[] = { { "day", IPT_LIMIT_SCALE*24*60*60 }, |
| 141 | { "hour", IPT_LIMIT_SCALE*60*60 }, |
| 142 | { "min", IPT_LIMIT_SCALE*60 }, |
| 143 | { "sec", IPT_LIMIT_SCALE } }; |
| 144 | |
| 145 | static void print_rate(u_int32_t period) |
| 146 | { |
| 147 | unsigned int i; |
| 148 | |
| 149 | for (i = 1; i < sizeof(rates)/sizeof(struct rates); i++) { |
| 150 | if (period > rates[i].mult |
| 151 | || rates[i].mult % period != 0) |
| 152 | break; |
| 153 | } |
| 154 | |
| 155 | printf("%u/%s ", rates[i-1].mult / period, rates[i-1].name); |
| 156 | } |
| 157 | |
| 158 | /* Prints out the matchinfo. */ |
| 159 | static void |
| 160 | print(const struct ipt_ip *ip, |
| 161 | const struct ipt_entry_match *match, |
| 162 | int numeric) |
| 163 | { |
| 164 | struct ipt_rateinfo *r = (struct ipt_rateinfo *)match->data; |
| 165 | printf("limit: avg "); print_rate(r->avg); |
| 166 | printf("burst %u ", r->burst); |
| 167 | } |
| 168 | |
| 169 | /* FIXME: Make minimalist: only print rate if not default --RR */ |
| 170 | static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match) |
| 171 | { |
| 172 | struct ipt_rateinfo *r = (struct ipt_rateinfo *)match->data; |
| 173 | |
| 174 | printf("--limit "); print_rate(r->avg); |
| 175 | if (r->burst != IPT_LIMIT_BURST) |
| 176 | printf("--limit-burst %u ", r->burst); |
| 177 | } |
| 178 | |
| 179 | struct iptables_match limit |
| 180 | = { NULL, |
| 181 | "limit", |
| 182 | NETFILTER_VERSION, |
| 183 | sizeof(struct ipt_rateinfo), |
| 184 | &help, |
| 185 | &init, |
| 186 | &parse, |
| 187 | &final_check, |
| 188 | &print, |
| 189 | &save, |
| 190 | opts |
| 191 | }; |
| 192 | |
| 193 | void _init(void) |
| 194 | { |
| 195 | register_match(&limit); |
| 196 | } |