Forum Debian Users Gang

/* Shared library add-on to iptables to add connection rate tracking
 * support.
 *
 * Copyright (c) 2004 Nuutti Kotivuori <naked@iki.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 **/
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>
#include <linux/netfilter_ipv4/ipt_connrate.h>

/* Function which prints out usage message. */
static void
help(void)
{
    printf(
"connrate v%s options:\n"
" --connrate [!] [from]:[to]\n"
"                Match connection transfer rate in bytes\n"
"                per second. `inf' can be used for maximum\n"
"                expressible value.\n"
"\n", IPTABLES_VERSION);
}

static struct option opts[] = {
    { "connrate", 1, 0, '1' },
    {0}
};

static u_int32_t
parse_value(const char *arg, u_int32_t def)
{
    char *end;
    size_t len;
    u_int32_t value;

    len = strlen(arg);
    if(len == 0)
        return def;
    if(strcmp(arg, "inf") == 0)
        return 0xFFFFFFFF;
    value = strtoul(arg, &end, 0);
    if(*end != '\0')
        exit_error(PARAMETER_PROBLEM,
               "Bad value in range `%s'", arg);
    return value;
}

static void
parse_range(const char *arg, struct ipt_connrate_info *si)
{
    char *buffer;
    char *colon;

    buffer = strdup(arg);
    if ((colon = strchr(buffer, ':')) == NULL)
        exit_error(PARAMETER_PROBLEM, "Bad range `%s'", arg);
    *colon = '\0';
    si->from = parse_value(buffer, 0);
    si->to = parse_value(colon+1, 0xFFFFFFFF);
    if (si->from > si->to)
        exit_error(PARAMETER_PROBLEM, "%u should be less than %u", si->from,si->to);
    free(buffer);
}

#define CONNRATE_OPT 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 ipt_entry *entry,
      unsigned int *nfcache,
      struct ipt_entry_match **match)
{
    struct ipt_connrate_info *sinfo = (struct ipt_connrate_info *)(*match)->data;
    u_int32_t tmp;

    switch (c) {
    case '1':
        if (*flags & CONNRATE_OPT)
            exit_error(PARAMETER_PROBLEM,
                   "Only one `--connrate' allowed");
        check_inverse(optarg, &invert, &optind, 0);
        parse_range(argv[optind-1], sinfo);
        if (invert) {
            tmp = sinfo->from;
            sinfo->from = sinfo->to;
            sinfo->to = tmp;
        }
        *flags |= CONNRATE_OPT;
        break;

    default:
        return 0;
    }

    return 1;
}

static void final_check(unsigned int flags)
{
    if (!(flags & CONNRATE_OPT))
        exit_error(PARAMETER_PROBLEM,
               "connrate match: You must specify `--connrate'");
}

static void
print_value(u_int32_t value)
{
    if(value == 0xFFFFFFFF)
        printf("inf");
    else
        printf("%u", value);
}

static void
print_range(struct ipt_connrate_info *sinfo)
{
    if (sinfo->from > sinfo->to) {
        printf("! ");
        print_value(sinfo->to);
        printf(":");
        print_value(sinfo->from);
    } else {
        print_value(sinfo->from);
        printf(":");
        print_value(sinfo->to);
    }
}

/* Prints out the matchinfo. */
static void
print(const struct ipt_ip *ip,
      const struct ipt_entry_match *match,
      int numeric)
{
    struct ipt_connrate_info *sinfo = (struct ipt_connrate_info *)match->data;

    printf("connrate ");
    print_range(sinfo);
    printf(" ");
}

/* Saves the matchinfo in parsable form to stdout. */
static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
    struct ipt_connrate_info *sinfo = (struct ipt_connrate_info *)match->data;

    printf("--connrate ");
    print_range(sinfo);
    printf(" ");
}

static struct iptables_match state = { 
    .next         = NULL,
    .name        = "connrate",
    .version    = IPTABLES_VERSION,
    .size        = IPT_ALIGN(sizeof(struct ipt_connrate_info)),
    .userspacesize    = IPT_ALIGN(sizeof(struct ipt_connrate_info)),
    .help         = &help,
    .parse        = &parse,
    .final_check    = &final_check,
    .print        = &print,
    .save        = &save,
    .extra_opts    = opts
};

void _init(void)
{
    register_match(&state);
}