| /* |
| * Copyright (c) 2006-2013 Patrick McHardy <kaber@trash.net> |
| */ |
| |
| #include <math.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <xtables.h> |
| #include <linux/netfilter/xt_statistic.h> |
| |
| enum { |
| O_MODE = 0, |
| O_PROBABILITY, |
| O_EVERY, |
| O_PACKET, |
| F_PROBABILITY = 1 << O_PROBABILITY, |
| F_EVERY = 1 << O_EVERY, |
| F_PACKET = 1 << O_PACKET, |
| }; |
| |
| static void statistic_help(void) |
| { |
| printf( |
| "statistic match options:\n" |
| " --mode mode Match mode (random, nth)\n" |
| " random mode:\n" |
| "[!] --probability p Probability\n" |
| " nth mode:\n" |
| "[!] --every n Match every nth packet\n" |
| " --packet p Initial counter value (0 <= p <= n-1, default 0)\n"); |
| } |
| |
| #define s struct xt_statistic_info |
| static const struct xt_option_entry statistic_opts[] = { |
| {.name = "mode", .id = O_MODE, .type = XTTYPE_STRING, |
| .flags = XTOPT_MAND}, |
| {.name = "probability", .id = O_PROBABILITY, .type = XTTYPE_DOUBLE, |
| .flags = XTOPT_INVERT, .min = 0, .max = 1, |
| .excl = F_EVERY | F_PACKET}, |
| {.name = "every", .id = O_EVERY, .type = XTTYPE_UINT32, .min = 1, |
| .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, u.nth.every), |
| .excl = F_PROBABILITY, .also = F_PACKET}, |
| {.name = "packet", .id = O_PACKET, .type = XTTYPE_UINT32, |
| .flags = XTOPT_PUT, XTOPT_POINTER(s, u.nth.packet), |
| .excl = F_PROBABILITY, .also = F_EVERY}, |
| XTOPT_TABLEEND, |
| }; |
| #undef s |
| |
| static void statistic_parse(struct xt_option_call *cb) |
| { |
| struct xt_statistic_info *info = cb->data; |
| |
| if (cb->invert) |
| info->flags |= XT_STATISTIC_INVERT; |
| |
| xtables_option_parse(cb); |
| switch (cb->entry->id) { |
| case O_MODE: |
| if (strcmp(cb->arg, "random") == 0) |
| info->mode = XT_STATISTIC_MODE_RANDOM; |
| else if (strcmp(cb->arg, "nth") == 0) |
| info->mode = XT_STATISTIC_MODE_NTH; |
| else |
| xtables_error(PARAMETER_PROBLEM, "Bad mode \"%s\"", |
| cb->arg); |
| break; |
| case O_PROBABILITY: |
| info->u.random.probability = lround(0x80000000 * cb->val.dbl); |
| break; |
| case O_EVERY: |
| --info->u.nth.every; |
| break; |
| } |
| } |
| |
| static void statistic_check(struct xt_fcheck_call *cb) |
| { |
| struct xt_statistic_info *info = cb->data; |
| |
| if (info->mode == XT_STATISTIC_MODE_RANDOM && |
| !(cb->xflags & F_PROBABILITY)) |
| xtables_error(PARAMETER_PROBLEM, |
| "--probability must be specified when using " |
| "random mode"); |
| if (info->mode == XT_STATISTIC_MODE_NTH && |
| !(cb->xflags & (F_EVERY | F_PACKET))) |
| xtables_error(PARAMETER_PROBLEM, |
| "--every and --packet must be specified when " |
| "using nth mode"); |
| |
| /* at this point, info->u.nth.every have been decreased. */ |
| if (info->u.nth.packet > info->u.nth.every) |
| xtables_error(PARAMETER_PROBLEM, |
| "the --packet p must be 0 <= p <= n-1"); |
| |
| info->u.nth.count = info->u.nth.every - info->u.nth.packet; |
| } |
| |
| static void print_match(const struct xt_statistic_info *info, char *prefix) |
| { |
| switch (info->mode) { |
| case XT_STATISTIC_MODE_RANDOM: |
| printf(" %smode random%s %sprobability %.11f", prefix, |
| (info->flags & XT_STATISTIC_INVERT) ? " !" : "", |
| prefix, |
| 1.0 * info->u.random.probability / 0x80000000); |
| break; |
| case XT_STATISTIC_MODE_NTH: |
| printf(" %smode nth%s %severy %u", prefix, |
| (info->flags & XT_STATISTIC_INVERT) ? " !" : "", |
| prefix, |
| info->u.nth.every + 1); |
| if (info->u.nth.packet || *prefix) |
| printf(" %spacket %u", prefix, info->u.nth.packet); |
| break; |
| } |
| } |
| |
| static void |
| statistic_print(const void *ip, const struct xt_entry_match *match, int numeric) |
| { |
| const struct xt_statistic_info *info = (const void *)match->data; |
| |
| printf(" statistic"); |
| print_match(info, ""); |
| } |
| |
| static void statistic_save(const void *ip, const struct xt_entry_match *match) |
| { |
| const struct xt_statistic_info *info = (const void *)match->data; |
| |
| print_match(info, "--"); |
| } |
| |
| static int statistic_xlate(struct xt_xlate *xl, |
| const struct xt_xlate_mt_params *params) |
| { |
| const struct xt_statistic_info *info = |
| (struct xt_statistic_info *)params->match->data; |
| |
| switch (info->mode) { |
| case XT_STATISTIC_MODE_RANDOM: |
| return 0; |
| case XT_STATISTIC_MODE_NTH: |
| xt_xlate_add(xl, "numgen inc mod %u %s%u", |
| info->u.nth.every + 1, |
| info->flags & XT_STATISTIC_INVERT ? "!= " : "", |
| info->u.nth.packet); |
| break; |
| } |
| |
| return 1; |
| } |
| |
| static struct xtables_match statistic_match = { |
| .family = NFPROTO_UNSPEC, |
| .name = "statistic", |
| .version = XTABLES_VERSION, |
| .size = XT_ALIGN(sizeof(struct xt_statistic_info)), |
| .userspacesize = offsetof(struct xt_statistic_info, u.nth.count), |
| .help = statistic_help, |
| .x6_parse = statistic_parse, |
| .x6_fcheck = statistic_check, |
| .print = statistic_print, |
| .save = statistic_save, |
| .x6_options = statistic_opts, |
| .xlate = statistic_xlate, |
| }; |
| |
| void _init(void) |
| { |
| xtables_register_match(&statistic_match); |
| } |