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/* Amanda extension for IP connection tracking, Version 0.2
* (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
* based on HW's ip_conntrack_irc.c as well as other modules
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Module load syntax:
* insmod ip_conntrack_amanda.o [master_timeout=n]
*
* Where master_timeout is the timeout (in seconds) of the master
* connection (port 10080). This defaults to 5 minutes but if
* your clients take longer than 5 minutes to do their work
* before getting back to the Amanda server, you can increase
* this value.
*
*/
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/ip.h>
#include <linux/moduleparam.h>
#include <linux/udp.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
static unsigned int master_timeout = 300;
MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
MODULE_DESCRIPTION("Amanda connection tracking module");
MODULE_LICENSE("GPL");
module_param(master_timeout, int, 0600);
MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
static const char *conns[] = { "DATA ", "MESG ", "INDEX " };
/* This is slow, but it's simple. --RR */
static char *amanda_buffer;
static DEFINE_SPINLOCK(amanda_buffer_lock);
unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
unsigned int matchoff,
unsigned int matchlen,
struct ip_conntrack_expect *exp);
EXPORT_SYMBOL_GPL(ip_nat_amanda_hook);
static int help(struct sk_buff **pskb,
struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
{
struct ip_conntrack_expect *exp;
char *data, *data_limit, *tmp;
unsigned int dataoff, i;
u_int16_t port, len;
int ret = NF_ACCEPT;
/* Only look at packets from the Amanda server */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
return NF_ACCEPT;
/* increase the UDP timeout of the master connection as replies from
* Amanda clients to the server can be quite delayed */
ip_ct_refresh(ct, *pskb, master_timeout * HZ);
/* No data? */
dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
if (dataoff >= (*pskb)->len) {
if (net_ratelimit())
printk("amanda_help: skblen = %u\n", (*pskb)->len);
return NF_ACCEPT;
}
spin_lock_bh(&amanda_buffer_lock);
skb_copy_bits(*pskb, dataoff, amanda_buffer, (*pskb)->len - dataoff);
data = amanda_buffer;
data_limit = amanda_buffer + (*pskb)->len - dataoff;
*data_limit = '\0';
/* Search for the CONNECT string */
data = strstr(data, "CONNECT ");
if (!data)
goto out;
data += strlen("CONNECT ");
/* Only search first line. */
if ((tmp = strchr(data, '\n')))
*tmp = '\0';
for (i = 0; i < ARRAY_SIZE(conns); i++) {
char *match = strstr(data, conns[i]);
if (!match)
continue;
tmp = data = match + strlen(conns[i]);
port = simple_strtoul(data, &data, 10);
len = data - tmp;
if (port == 0 || len > 5)
break;
exp = ip_conntrack_expect_alloc(ct);
if (exp == NULL) {
ret = NF_DROP;
goto out;
}
exp->expectfn = NULL;
exp->flags = 0;
exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
exp->tuple.src.u.tcp.port = 0;
exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
exp->tuple.dst.protonum = IPPROTO_TCP;
exp->tuple.dst.u.tcp.port = htons(port);
exp->mask.src.ip = 0xFFFFFFFF;
exp->mask.src.u.tcp.port = 0;
exp->mask.dst.ip = 0xFFFFFFFF;
exp->mask.dst.protonum = 0xFF;
exp->mask.dst.u.tcp.port = 0xFFFF;
if (ip_nat_amanda_hook)
ret = ip_nat_amanda_hook(pskb, ctinfo,
tmp - amanda_buffer,
len, exp);
else if (ip_conntrack_expect_related(exp) != 0)
ret = NF_DROP;
ip_conntrack_expect_put(exp);
}
out:
spin_unlock_bh(&amanda_buffer_lock);
return ret;
}
static struct ip_conntrack_helper amanda_helper = {
.max_expected = ARRAY_SIZE(conns),
.timeout = 180,
.me = THIS_MODULE,
.help = help,
.name = "amanda",
.tuple = { .src = { .u = { __constant_htons(10080) } },
.dst = { .protonum = IPPROTO_UDP },
},
.mask = { .src = { .u = { 0xFFFF } },
.dst = { .protonum = 0xFF },
},
};
static void __exit fini(void)
{
ip_conntrack_helper_unregister(&amanda_helper);
kfree(amanda_buffer);
}
static int __init init(void)
{
int ret;
amanda_buffer = kmalloc(65536, GFP_KERNEL);
if (!amanda_buffer)
return -ENOMEM;
ret = ip_conntrack_helper_register(&amanda_helper);
if (ret < 0) {
kfree(amanda_buffer);
return ret;
}
return 0;
}
module_init(init);
module_exit(fini);
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