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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
*
* 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.
*
* 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>
#include <linux/moduleparam.h>
MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
MODULE_DESCRIPTION("tftp connection tracking helper");
MODULE_LICENSE("GPL");
#define MAX_PORTS 8
static int ports[MAX_PORTS];
static int ports_c;
module_param_array(ports, int, &ports_c, 0400);
MODULE_PARM_DESC(ports, "port numbers of tftp servers");
#if 0
#define DEBUGP(format, args...) printk("%s:%s:" format, \
__FILE__, __FUNCTION__ , ## args)
#else
#define DEBUGP(format, args...)
#endif
unsigned int (*ip_nat_tftp_hook)(struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
struct ip_conntrack_expect *exp);
EXPORT_SYMBOL_GPL(ip_nat_tftp_hook);
static int tftp_help(struct sk_buff **pskb,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo)
{
struct tftphdr _tftph, *tfh;
struct ip_conntrack_expect *exp;
unsigned int ret = NF_ACCEPT;
tfh = skb_header_pointer(*pskb,
(*pskb)->nh.iph->ihl*4+sizeof(struct udphdr),
sizeof(_tftph), &_tftph);
if (tfh == NULL)
return NF_ACCEPT;
switch (ntohs(tfh->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);
exp = ip_conntrack_expect_alloc();
if (exp == NULL)
return NF_DROP;
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 = 0xff;
exp->expectfn = NULL;
exp->master = ct;
DEBUGP("expect: ");
DUMP_TUPLE(&exp->tuple);
DUMP_TUPLE(&exp->mask);
if (ip_nat_tftp_hook)
ret = ip_nat_tftp_hook(pskb, ctinfo, exp);
else if (ip_conntrack_expect_related(exp) != 0) {
ip_conntrack_expect_free(exp);
ret = NF_DROP;
}
break;
case TFTP_OPCODE_DATA:
case TFTP_OPCODE_ACK:
DEBUGP("Data/ACK opcode\n");
break;
case TFTP_OPCODE_ERROR:
DEBUGP("Error opcode\n");
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_c == 0)
ports[ports_c++] = TFTP_PORT;
for (i = 0; i < ports_c; i++) {
/* Create helper structure */
memset(&tftp[i], 0, sizeof(struct ip_conntrack_helper));
tftp[i].tuple.dst.protonum = IPPROTO_UDP;
tftp[i].tuple.src.u.udp.port = htons(ports[i]);
tftp[i].mask.dst.protonum = 0xFF;
tftp[i].mask.src.u.udp.port = 0xFFFF;
tftp[i].max_expected = 1;
tftp[i].timeout = 5 * 60; /* 5 minutes */
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);
}
}
return(0);
}
module_init(init);
module_exit(fini);
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