From 62fb4593f22e666b1fe3065be9d0c72a75dc91e4 Mon Sep 17 00:00:00 2001 From: Maciej Soltysiak Date: Sat, 3 May 2003 13:46:18 +0000 Subject: add random6 patch (Maciej Soltysiak) --- extensions/.random-test6 | 3 + extensions/libip6t_random.c | 152 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 155 insertions(+) create mode 100755 extensions/.random-test6 create mode 100644 extensions/libip6t_random.c (limited to 'extensions') diff --git a/extensions/.random-test6 b/extensions/.random-test6 new file mode 100755 index 00000000..25a431fd --- /dev/null +++ b/extensions/.random-test6 @@ -0,0 +1,3 @@ +#!/bin/sh +# True if random is applied. +[ -f $KERNEL_DIR/include/linux/netfilter_ipv6/ip6t_random.h ] && echo random diff --git a/extensions/libip6t_random.c b/extensions/libip6t_random.c new file mode 100644 index 00000000..5f151eac --- /dev/null +++ b/extensions/libip6t_random.c @@ -0,0 +1,152 @@ +/* + Shared library add-on to iptables to add match support for random match. + + This file is distributed under the terms of the GNU General Public + License (GPL). Copies of the GPL can be obtained from: + ftp://prep.ai.mit.edu/pub/gnu/GPL + + 2001-10-14 Fabrice MARIE : initial development. + 2003-04-30 Maciej Soltysiak : IPv6 port. +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * The kernel random routing returns numbers between 0 and 255. + * To ease the task of the user in choosing the probability + * of matching, we want him to be able to use percentages. + * Therefore we have to accept numbers in percentage here, + * turn them into number between 0 and 255 for the kernel module, + * and turn them back to percentages when we print/save + * the rule. + */ + + +/* Function which prints out usage message. */ +static void +help(void) +{ + printf( +"random v%s options:\n" +" [--average] percent The probability in percentage of the match\n" +" If ommited, a probability of 50%% percent is set.\n" +" Percentage must be within : 1 <= percent <= 99.\n\n", +IPTABLES_VERSION); +} + +static struct option opts[] = { + { "average", 1, 0, '1' }, + { 0 } +}; + +/* Initialize the target. */ +static void +init(struct ip6t_entry_match *m, unsigned int *nfcache) +{ + struct ip6t_rand_info *randinfo = (struct ip6t_rand_info *)(m)->data; + *nfcache |= NFC_UNKNOWN; + + /* We assign the average to be 50 which is our default value */ + /* 50 * 2.55 = 128 */ + randinfo->average = 128; +} + +#define IP6T_RAND_OPT_AVERAGE 0x01 + +/* Function which parses command options; returns true if it + ate an option */ +static int +parse(int c, char **argv, int invert, unsigned int *flags, + const struct ip6t_entry *entry, + unsigned int *nfcache, + struct ip6t_entry_match **match) +{ + struct ip6t_rand_info *randinfo = (struct ip6t_rand_info *)(*match)->data; + unsigned int num; + + switch (c) { + case '1': + /* check for common mistakes... */ + if (invert) + exit_error(PARAMETER_PROBLEM, + "Can't specify ! --average"); + if (*flags & IP6T_RAND_OPT_AVERAGE) + exit_error(PARAMETER_PROBLEM, + "Can't specify --average twice"); + + /* Remember, this function will interpret a leading 0 to be + Octal, a leading 0x to be hexdecimal... */ + if (string_to_number(optarg, 1, 99, &num) == -1 || num < 1) + exit_error(PARAMETER_PROBLEM, + "bad --average `%s', must be between 1 and 99", optarg); + + /* assign the values */ + randinfo->average = (int)(num * 2.55); + *flags |= IP6T_RAND_OPT_AVERAGE; + break; + default: + return 0; + } + return 1; +} + +/* Final check; nothing. */ +static void final_check(unsigned int flags) +{ +} + +/* Prints out the targinfo. */ +static void +print(const struct ip6t_ip6 *ip, + const struct ip6t_entry_match *match, + int numeric) +{ + const struct ip6t_rand_info *randinfo + = (const struct ip6t_rand_info *)match->data; + div_t result = div((randinfo->average*100), 255); + if (result.rem > 127) /* round up... */ + ++result.quot; + + printf(" random %u%% ", result.quot); +} + +/* Saves the union ip6t_targinfo in parsable form to stdout. */ +static void +save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match) +{ + const struct ip6t_rand_info *randinfo + = (const struct ip6t_rand_info *)match->data; + div_t result = div((randinfo->average *100), 255); + if (result.rem > 127) /* round up... */ + ++result.quot; + + printf("--average %u ", result.quot); +} + +struct ip6tables_match rand_match += { NULL, + "random", + IPTABLES_VERSION, + IP6T_ALIGN(sizeof(struct ip6t_rand_info)), + IP6T_ALIGN(sizeof(struct ip6t_rand_info)), + &help, + &init, + &parse, + &final_check, + &print, + &save, + opts +}; + +void _init(void) +{ + register_match6(&rand_match); +} -- cgit v1.2.3