![Patrick McHardy](/assets/img/avatar_default.png)
Since conntrack currently allows to use masks for every bit of both helper and expectation tuples, we can't hash them and have to keep them on two global lists that are searched for every new connection. This patch removes the never used ability to use masks for the destination part of the expectation tuple and completely removes masks from helpers since the only reasonable choice is a full match on l3num, protonum and src.u.all. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
279 lines
7.6 KiB
C
279 lines
7.6 KiB
C
/* IRC extension for IP connection tracking, Version 1.21
|
|
* (C) 2000-2002 by Harald Welte <laforge@gnumonks.org>
|
|
* based on RR's ip_conntrack_ftp.c
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/in.h>
|
|
#include <linux/tcp.h>
|
|
#include <linux/netfilter.h>
|
|
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_expect.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <linux/netfilter/nf_conntrack_irc.h>
|
|
|
|
#define MAX_PORTS 8
|
|
static unsigned short ports[MAX_PORTS];
|
|
static int ports_c;
|
|
static unsigned int max_dcc_channels = 8;
|
|
static unsigned int dcc_timeout __read_mostly = 300;
|
|
/* This is slow, but it's simple. --RR */
|
|
static char *irc_buffer;
|
|
static DEFINE_SPINLOCK(irc_buffer_lock);
|
|
|
|
unsigned int (*nf_nat_irc_hook)(struct sk_buff **pskb,
|
|
enum ip_conntrack_info ctinfo,
|
|
unsigned int matchoff,
|
|
unsigned int matchlen,
|
|
struct nf_conntrack_expect *exp) __read_mostly;
|
|
EXPORT_SYMBOL_GPL(nf_nat_irc_hook);
|
|
|
|
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
|
|
MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("ip_conntrack_irc");
|
|
|
|
module_param_array(ports, ushort, &ports_c, 0400);
|
|
MODULE_PARM_DESC(ports, "port numbers of IRC servers");
|
|
module_param(max_dcc_channels, uint, 0400);
|
|
MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per "
|
|
"IRC session");
|
|
module_param(dcc_timeout, uint, 0400);
|
|
MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels");
|
|
|
|
static const char *dccprotos[] = {
|
|
"SEND ", "CHAT ", "MOVE ", "TSEND ", "SCHAT "
|
|
};
|
|
|
|
#define MINMATCHLEN 5
|
|
|
|
#if 0
|
|
#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s:" format, \
|
|
__FILE__, __FUNCTION__ , ## args)
|
|
#else
|
|
#define DEBUGP(format, args...)
|
|
#endif
|
|
|
|
/* tries to get the ip_addr and port out of a dcc command
|
|
* return value: -1 on failure, 0 on success
|
|
* data pointer to first byte of DCC command data
|
|
* data_end pointer to last byte of dcc command data
|
|
* ip returns parsed ip of dcc command
|
|
* port returns parsed port of dcc command
|
|
* ad_beg_p returns pointer to first byte of addr data
|
|
* ad_end_p returns pointer to last byte of addr data
|
|
*/
|
|
static int parse_dcc(char *data, char *data_end, u_int32_t *ip,
|
|
u_int16_t *port, char **ad_beg_p, char **ad_end_p)
|
|
{
|
|
/* at least 12: "AAAAAAAA P\1\n" */
|
|
while (*data++ != ' ')
|
|
if (data > data_end - 12)
|
|
return -1;
|
|
|
|
*ad_beg_p = data;
|
|
*ip = simple_strtoul(data, &data, 10);
|
|
|
|
/* skip blanks between ip and port */
|
|
while (*data == ' ') {
|
|
if (data >= data_end)
|
|
return -1;
|
|
data++;
|
|
}
|
|
|
|
*port = simple_strtoul(data, &data, 10);
|
|
*ad_end_p = data;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int help(struct sk_buff **pskb, unsigned int protoff,
|
|
struct nf_conn *ct, enum ip_conntrack_info ctinfo)
|
|
{
|
|
unsigned int dataoff;
|
|
struct tcphdr _tcph, *th;
|
|
char *data, *data_limit, *ib_ptr;
|
|
int dir = CTINFO2DIR(ctinfo);
|
|
struct nf_conntrack_expect *exp;
|
|
struct nf_conntrack_tuple *tuple;
|
|
u_int32_t dcc_ip;
|
|
u_int16_t dcc_port;
|
|
__be16 port;
|
|
int i, ret = NF_ACCEPT;
|
|
char *addr_beg_p, *addr_end_p;
|
|
typeof(nf_nat_irc_hook) nf_nat_irc;
|
|
|
|
/* If packet is coming from IRC server */
|
|
if (dir == IP_CT_DIR_REPLY)
|
|
return NF_ACCEPT;
|
|
|
|
/* Until there's been traffic both ways, don't look in packets. */
|
|
if (ctinfo != IP_CT_ESTABLISHED &&
|
|
ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY)
|
|
return NF_ACCEPT;
|
|
|
|
/* Not a full tcp header? */
|
|
th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
|
|
if (th == NULL)
|
|
return NF_ACCEPT;
|
|
|
|
/* No data? */
|
|
dataoff = protoff + th->doff*4;
|
|
if (dataoff >= (*pskb)->len)
|
|
return NF_ACCEPT;
|
|
|
|
spin_lock_bh(&irc_buffer_lock);
|
|
ib_ptr = skb_header_pointer(*pskb, dataoff, (*pskb)->len - dataoff,
|
|
irc_buffer);
|
|
BUG_ON(ib_ptr == NULL);
|
|
|
|
data = ib_ptr;
|
|
data_limit = ib_ptr + (*pskb)->len - dataoff;
|
|
|
|
/* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
|
|
* 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
|
|
while (data < data_limit - (19 + MINMATCHLEN)) {
|
|
if (memcmp(data, "\1DCC ", 5)) {
|
|
data++;
|
|
continue;
|
|
}
|
|
data += 5;
|
|
/* we have at least (19+MINMATCHLEN)-5 bytes valid data left */
|
|
|
|
DEBUGP("DCC found in master %u.%u.%u.%u:%u %u.%u.%u.%u:%u...\n",
|
|
NIPQUAD(iph->saddr), ntohs(th->source),
|
|
NIPQUAD(iph->daddr), ntohs(th->dest));
|
|
|
|
for (i = 0; i < ARRAY_SIZE(dccprotos); i++) {
|
|
if (memcmp(data, dccprotos[i], strlen(dccprotos[i]))) {
|
|
/* no match */
|
|
continue;
|
|
}
|
|
data += strlen(dccprotos[i]);
|
|
DEBUGP("DCC %s detected\n", dccprotos[i]);
|
|
|
|
/* we have at least
|
|
* (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid
|
|
* data left (== 14/13 bytes) */
|
|
if (parse_dcc((char *)data, data_limit, &dcc_ip,
|
|
&dcc_port, &addr_beg_p, &addr_end_p)) {
|
|
DEBUGP("unable to parse dcc command\n");
|
|
continue;
|
|
}
|
|
DEBUGP("DCC bound ip/port: %u.%u.%u.%u:%u\n",
|
|
HIPQUAD(dcc_ip), dcc_port);
|
|
|
|
/* dcc_ip can be the internal OR external (NAT'ed) IP */
|
|
tuple = &ct->tuplehash[dir].tuple;
|
|
if (tuple->src.u3.ip != htonl(dcc_ip) &&
|
|
tuple->dst.u3.ip != htonl(dcc_ip)) {
|
|
if (net_ratelimit())
|
|
printk(KERN_WARNING
|
|
"Forged DCC command from "
|
|
"%u.%u.%u.%u: %u.%u.%u.%u:%u\n",
|
|
NIPQUAD(tuple->src.u3.ip),
|
|
HIPQUAD(dcc_ip), dcc_port);
|
|
continue;
|
|
}
|
|
|
|
exp = nf_ct_expect_alloc(ct);
|
|
if (exp == NULL) {
|
|
ret = NF_DROP;
|
|
goto out;
|
|
}
|
|
tuple = &ct->tuplehash[!dir].tuple;
|
|
port = htons(dcc_port);
|
|
nf_ct_expect_init(exp, tuple->src.l3num,
|
|
NULL, &tuple->dst.u3,
|
|
IPPROTO_TCP, NULL, &port);
|
|
|
|
nf_nat_irc = rcu_dereference(nf_nat_irc_hook);
|
|
if (nf_nat_irc && ct->status & IPS_NAT_MASK)
|
|
ret = nf_nat_irc(pskb, ctinfo,
|
|
addr_beg_p - ib_ptr,
|
|
addr_end_p - addr_beg_p,
|
|
exp);
|
|
else if (nf_ct_expect_related(exp) != 0)
|
|
ret = NF_DROP;
|
|
nf_ct_expect_put(exp);
|
|
goto out;
|
|
}
|
|
}
|
|
out:
|
|
spin_unlock_bh(&irc_buffer_lock);
|
|
return ret;
|
|
}
|
|
|
|
static struct nf_conntrack_helper irc[MAX_PORTS] __read_mostly;
|
|
static char irc_names[MAX_PORTS][sizeof("irc-65535")] __read_mostly;
|
|
|
|
static void nf_conntrack_irc_fini(void);
|
|
|
|
static int __init nf_conntrack_irc_init(void)
|
|
{
|
|
int i, ret;
|
|
char *tmpname;
|
|
|
|
if (max_dcc_channels < 1) {
|
|
printk("nf_ct_irc: max_dcc_channels must not be zero\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
irc_buffer = kmalloc(65536, GFP_KERNEL);
|
|
if (!irc_buffer)
|
|
return -ENOMEM;
|
|
|
|
/* If no port given, default to standard irc port */
|
|
if (ports_c == 0)
|
|
ports[ports_c++] = IRC_PORT;
|
|
|
|
for (i = 0; i < ports_c; i++) {
|
|
irc[i].tuple.src.l3num = AF_INET;
|
|
irc[i].tuple.src.u.tcp.port = htons(ports[i]);
|
|
irc[i].tuple.dst.protonum = IPPROTO_TCP;
|
|
irc[i].max_expected = max_dcc_channels;
|
|
irc[i].timeout = dcc_timeout;
|
|
irc[i].me = THIS_MODULE;
|
|
irc[i].help = help;
|
|
|
|
tmpname = &irc_names[i][0];
|
|
if (ports[i] == IRC_PORT)
|
|
sprintf(tmpname, "irc");
|
|
else
|
|
sprintf(tmpname, "irc-%u", i);
|
|
irc[i].name = tmpname;
|
|
|
|
ret = nf_conntrack_helper_register(&irc[i]);
|
|
if (ret) {
|
|
printk("nf_ct_irc: failed to register helper "
|
|
"for pf: %u port: %u\n",
|
|
irc[i].tuple.src.l3num, ports[i]);
|
|
nf_conntrack_irc_fini();
|
|
return ret;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* This function is intentionally _NOT_ defined as __exit, because
|
|
* it is needed by the init function */
|
|
static void nf_conntrack_irc_fini(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < ports_c; i++)
|
|
nf_conntrack_helper_unregister(&irc[i]);
|
|
kfree(irc_buffer);
|
|
}
|
|
|
|
module_init(nf_conntrack_irc_init);
|
|
module_exit(nf_conntrack_irc_fini);
|