1/* 2 * Copyright (c) 2006-2013 Patrick McHardy <kaber@trash.net> 3 */ 4 5#include <math.h> 6#include <stdio.h> 7#include <string.h> 8#include <xtables.h> 9#include <linux/netfilter/xt_statistic.h> 10 11enum { 12 O_MODE = 0, 13 O_PROBABILITY, 14 O_EVERY, 15 O_PACKET, 16 F_PROBABILITY = 1 << O_PROBABILITY, 17 F_EVERY = 1 << O_EVERY, 18 F_PACKET = 1 << O_PACKET, 19}; 20 21static void statistic_help(void) 22{ 23 printf( 24"statistic match options:\n" 25" --mode mode Match mode (random, nth)\n" 26" random mode:\n" 27"[!] --probability p Probability\n" 28" nth mode:\n" 29"[!] --every n Match every nth packet\n" 30" --packet p Initial counter value (0 <= p <= n-1, default 0)\n"); 31} 32 33#define s struct xt_statistic_info 34static const struct xt_option_entry statistic_opts[] = { 35 {.name = "mode", .id = O_MODE, .type = XTTYPE_STRING, 36 .flags = XTOPT_MAND}, 37 {.name = "probability", .id = O_PROBABILITY, .type = XTTYPE_DOUBLE, 38 .flags = XTOPT_INVERT, .min = 0, .max = 1, 39 .excl = F_EVERY | F_PACKET}, 40 {.name = "every", .id = O_EVERY, .type = XTTYPE_UINT32, .min = 1, 41 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, u.nth.every), 42 .excl = F_PROBABILITY, .also = F_PACKET}, 43 {.name = "packet", .id = O_PACKET, .type = XTTYPE_UINT32, 44 .flags = XTOPT_PUT, XTOPT_POINTER(s, u.nth.packet), 45 .excl = F_PROBABILITY, .also = F_EVERY}, 46 XTOPT_TABLEEND, 47}; 48#undef s 49 50static void statistic_parse(struct xt_option_call *cb) 51{ 52 struct xt_statistic_info *info = cb->data; 53 54 if (cb->invert) 55 info->flags |= XT_STATISTIC_INVERT; 56 57 xtables_option_parse(cb); 58 switch (cb->entry->id) { 59 case O_MODE: 60 if (strcmp(cb->arg, "random") == 0) 61 info->mode = XT_STATISTIC_MODE_RANDOM; 62 else if (strcmp(cb->arg, "nth") == 0) 63 info->mode = XT_STATISTIC_MODE_NTH; 64 else 65 xtables_error(PARAMETER_PROBLEM, "Bad mode \"%s\"", 66 cb->arg); 67 break; 68 case O_PROBABILITY: 69 info->u.random.probability = lround(0x80000000 * cb->val.dbl); 70 break; 71 case O_EVERY: 72 --info->u.nth.every; 73 break; 74 } 75} 76 77static void statistic_check(struct xt_fcheck_call *cb) 78{ 79 struct xt_statistic_info *info = cb->data; 80 81 if (info->mode == XT_STATISTIC_MODE_RANDOM && 82 !(cb->xflags & F_PROBABILITY)) 83 xtables_error(PARAMETER_PROBLEM, 84 "--probability must be specified when using " 85 "random mode"); 86 if (info->mode == XT_STATISTIC_MODE_NTH && 87 !(cb->xflags & (F_EVERY | F_PACKET))) 88 xtables_error(PARAMETER_PROBLEM, 89 "--every and --packet must be specified when " 90 "using nth mode"); 91 92 /* at this point, info->u.nth.every have been decreased. */ 93 if (info->u.nth.packet > info->u.nth.every) 94 xtables_error(PARAMETER_PROBLEM, 95 "the --packet p must be 0 <= p <= n-1"); 96 97 info->u.nth.count = info->u.nth.every - info->u.nth.packet; 98} 99 100static void print_match(const struct xt_statistic_info *info, char *prefix) 101{ 102 switch (info->mode) { 103 case XT_STATISTIC_MODE_RANDOM: 104 printf(" %smode random%s %sprobability %.11f", prefix, 105 (info->flags & XT_STATISTIC_INVERT) ? " !" : "", 106 prefix, 107 1.0 * info->u.random.probability / 0x80000000); 108 break; 109 case XT_STATISTIC_MODE_NTH: 110 printf(" %smode nth%s %severy %u", prefix, 111 (info->flags & XT_STATISTIC_INVERT) ? " !" : "", 112 prefix, 113 info->u.nth.every + 1); 114 if (info->u.nth.packet || *prefix) 115 printf(" %spacket %u", prefix, info->u.nth.packet); 116 break; 117 } 118} 119 120static void 121statistic_print(const void *ip, const struct xt_entry_match *match, int numeric) 122{ 123 const struct xt_statistic_info *info = (const void *)match->data; 124 125 printf(" statistic"); 126 print_match(info, ""); 127} 128 129static void statistic_save(const void *ip, const struct xt_entry_match *match) 130{ 131 const struct xt_statistic_info *info = (const void *)match->data; 132 133 print_match(info, "--"); 134} 135 136static struct xtables_match statistic_match = { 137 .family = NFPROTO_UNSPEC, 138 .name = "statistic", 139 .version = XTABLES_VERSION, 140 .size = XT_ALIGN(sizeof(struct xt_statistic_info)), 141 .userspacesize = offsetof(struct xt_statistic_info, u.nth.count), 142 .help = statistic_help, 143 .x6_parse = statistic_parse, 144 .x6_fcheck = statistic_check, 145 .print = statistic_print, 146 .save = statistic_save, 147 .x6_options = statistic_opts, 148}; 149 150void _init(void) 151{ 152 xtables_register_match(&statistic_match); 153} 154