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/*

 * Licensed under GNU GPL version 2 Copyright Magnus Boden <mb@ozaba.mine.nu>

 * Version: 0.0.7

 *

 * Thu 21 Mar 2002 Harald Welte <laforge@gnumonks.org>

 *      - port to newnat API

 *

 */

#include <linux/module.h>

#include <linux/ip.h>

#include <linux/udp.h>

#include <linux/netfilter.h>

#include <linux/netfilter_ipv4/ip_tables.h>

#include <linux/netfilter_ipv4/ip_conntrack_helper.h>

#include <linux/netfilter_ipv4/ip_conntrack_tftp.h>

MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");

MODULE_DESCRIPTION("Netfilter connection tracking module for tftp");

MODULE_LICENSE("GPL");

#define MAX_PORTS 8

static int ports[MAX_PORTS];

static int ports_c = 0;

#ifdef MODULE_PARM

MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_PORTS) "i");

MODULE_PARM_DESC(ports, "port numbers of tftp servers");

#endif

#if 0

#define DEBUGP(format, args...) printk(__FILE__ ":" __FUNCTION__ ": " \

                                       format, ## args)

#else

#define DEBUGP(format, args...)

#endif

static int tftp_help(const struct iphdr *iph, size_t len,

        struct ip_conntrack *ct,

        enum ip_conntrack_info ctinfo)

{

        struct udphdr *udph = (void *)iph + iph->ihl * 4;

        struct tftphdr *tftph = (void *)udph + 8;

        struct ip_conntrack_expect exp;

        switch (ntohs(tftph->opcode)) {

        /* RRQ and WRQ works the same way */

        case TFTP_OPCODE_READ:

        case TFTP_OPCODE_WRITE:

                DEBUGP("");

                DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);

                DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);

                memset(&exp, 0, sizeof(exp));

                exp.tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;

                exp.mask.src.ip = 0xffffffff;

                exp.mask.dst.ip = 0xffffffff;

                exp.mask.dst.u.udp.port = 0xffff;

                exp.mask.dst.protonum = 0xffff;

                exp.expectfn = NULL;

                DEBUGP("expect: ");

                DUMP_TUPLE(&exp.tuple);

                DUMP_TUPLE(&exp.mask);

                ip_conntrack_expect_related(ct, &exp);

                break;

        default:

                DEBUGP("Unknown opcode\n");

        }

        return NF_ACCEPT;

}

static struct ip_conntrack_helper tftp[MAX_PORTS];

static char tftp_names[MAX_PORTS][10];

static void fini(void)

{

        int i;

        for (i = 0 ; i < ports_c; i++) {

                DEBUGP("unregistering helper for port %d\n",

                        ports[i]);

                ip_conntrack_helper_unregister(&tftp[i]);

        }

}

static int __init init(void)

{

        int i, ret;

        char *tmpname;

        if (!ports[0])

                ports[0]=TFTP_PORT;

        for (i = 0 ; (i < MAX_PORTS) && ports[i] ; i++) {

                /* Create helper structure */

                tftp[i].tuple.dst.protonum = IPPROTO_UDP;

                tftp[i].tuple.src.u.udp.port = htons(ports[i]);

                tftp[i].mask.dst.protonum = 0xFFFF;

                tftp[i].mask.src.u.udp.port = 0xFFFF;

                tftp[i].max_expected = 1;

                tftp[i].timeout = 0;

                tftp[i].flags = IP_CT_HELPER_F_REUSE_EXPECT;

                tftp[i].me = THIS_MODULE;

                tftp[i].help = tftp_help;

                tmpname = &tftp_names[i][0];

                if (ports[i] == TFTP_PORT)

                        sprintf(tmpname, "tftp");

                else

                        sprintf(tmpname, "tftp-%d", i);

                tftp[i].name = tmpname;

                DEBUGP("port #%d: %d\n", i, ports[i]);

                ret=ip_conntrack_helper_register(&tftp[i]);

                if (ret) {

                        printk("ERROR registering helper for port %d\n",

                                ports[i]);

                        fini();

                        return(ret);

                }

                ports_c++;

        }

        return(0);

}

module_init(init);

module_exit(fini);