1 /* IRC extension for IP connection tracking, Version 1.21
2 * (C) 2000-2002 by Harald Welte <laforge@gnumonks.org>
3 * based on RR's ip_conntrack_ftp.c
5 * ip_conntrack_irc.c,v 1.21 2002/02/05 14:49:26 laforge Exp
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
13 * insmod ip_conntrack_irc.o ports=port1,port2,...port<MAX_PORTS>
14 * max_dcc_channels=n dcc_timeout=secs
16 * please give the ports of all IRC servers You wish to connect to.
17 * If You don't specify ports, the default will be port 6667.
18 * With max_dcc_channels you can define the maximum number of not
19 * yet answered DCC channels per IRC session (default 8).
20 * With dcc_timeout you can specify how long the system waits for
21 * an expected DCC channel (default 300 seconds).
25 #include <linux/module.h>
26 #include <linux/netfilter.h>
28 #include <net/checksum.h>
31 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
32 #include <linux/netfilter_ipv4/ip_conntrack_irc.h>
33 #include <linux/moduleparam.h>
36 static unsigned short ports
[MAX_PORTS
];
38 static unsigned int max_dcc_channels
= 8;
39 static unsigned int dcc_timeout
= 300;
40 /* This is slow, but it's simple. --RR */
41 static char *irc_buffer
;
42 static DEFINE_SPINLOCK(irc_buffer_lock
);
44 unsigned int (*ip_nat_irc_hook
)(struct sk_buff
**pskb
,
45 enum ip_conntrack_info ctinfo
,
46 unsigned int matchoff
,
47 unsigned int matchlen
,
48 struct ip_conntrack_expect
*exp
);
49 EXPORT_SYMBOL_GPL(ip_nat_irc_hook
);
51 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
52 MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
53 MODULE_LICENSE("GPL");
54 module_param_array(ports
, ushort
, &ports_c
, 0400);
55 MODULE_PARM_DESC(ports
, "port numbers of IRC servers");
56 module_param(max_dcc_channels
, uint
, 0400);
57 MODULE_PARM_DESC(max_dcc_channels
, "max number of expected DCC channels per IRC session");
58 module_param(dcc_timeout
, uint
, 0400);
59 MODULE_PARM_DESC(dcc_timeout
, "timeout on for unestablished DCC channels");
61 static const char *dccprotos
[] = { "SEND ", "CHAT ", "MOVE ", "TSEND ", "SCHAT " };
65 #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s:" format, \
66 __FILE__, __FUNCTION__ , ## args)
68 #define DEBUGP(format, args...)
71 static int parse_dcc(char *data
, char *data_end
, u_int32_t
*ip
,
72 u_int16_t
*port
, char **ad_beg_p
, char **ad_end_p
)
73 /* tries to get the ip_addr and port out of a dcc command
74 return value: -1 on failure, 0 on success
75 data pointer to first byte of DCC command data
76 data_end pointer to last byte of dcc command data
77 ip returns parsed ip of dcc command
78 port returns parsed port of dcc command
79 ad_beg_p returns pointer to first byte of addr data
80 ad_end_p returns pointer to last byte of addr data */
83 /* at least 12: "AAAAAAAA P\1\n" */
84 while (*data
++ != ' ')
85 if (data
> data_end
- 12)
89 *ip
= simple_strtoul(data
, &data
, 10);
91 /* skip blanks between ip and port */
92 while (*data
== ' ') {
98 *port
= simple_strtoul(data
, &data
, 10);
104 static int help(struct sk_buff
**pskb
,
105 struct ip_conntrack
*ct
, enum ip_conntrack_info ctinfo
)
107 unsigned int dataoff
;
108 struct tcphdr _tcph
, *th
;
109 char *data
, *data_limit
, *ib_ptr
;
110 int dir
= CTINFO2DIR(ctinfo
);
111 struct ip_conntrack_expect
*exp
;
115 int i
, ret
= NF_ACCEPT
;
116 char *addr_beg_p
, *addr_end_p
;
117 typeof(ip_nat_irc_hook
) ip_nat_irc
;
121 /* If packet is coming from IRC server */
122 if (dir
== IP_CT_DIR_REPLY
)
125 /* Until there's been traffic both ways, don't look in packets. */
126 if (ctinfo
!= IP_CT_ESTABLISHED
127 && ctinfo
!= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
) {
128 DEBUGP("Conntrackinfo = %u\n", ctinfo
);
132 /* Not a full tcp header? */
133 th
= skb_header_pointer(*pskb
, (*pskb
)->nh
.iph
->ihl
*4,
134 sizeof(_tcph
), &_tcph
);
139 dataoff
= (*pskb
)->nh
.iph
->ihl
*4 + th
->doff
*4;
140 if (dataoff
>= (*pskb
)->len
)
143 spin_lock_bh(&irc_buffer_lock
);
144 ib_ptr
= skb_header_pointer(*pskb
, dataoff
,
145 (*pskb
)->len
- dataoff
, irc_buffer
);
146 BUG_ON(ib_ptr
== NULL
);
149 data_limit
= ib_ptr
+ (*pskb
)->len
- dataoff
;
151 /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
152 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
153 while (data
< (data_limit
- (19 + MINMATCHLEN
))) {
154 if (memcmp(data
, "\1DCC ", 5)) {
160 /* we have at least (19+MINMATCHLEN)-5 bytes valid data left */
162 DEBUGP("DCC found in master %u.%u.%u.%u:%u %u.%u.%u.%u:%u...\n",
163 NIPQUAD(iph
->saddr
), ntohs(th
->source
),
164 NIPQUAD(iph
->daddr
), ntohs(th
->dest
));
166 for (i
= 0; i
< ARRAY_SIZE(dccprotos
); i
++) {
167 if (memcmp(data
, dccprotos
[i
], strlen(dccprotos
[i
]))) {
172 DEBUGP("DCC %s detected\n", dccprotos
[i
]);
173 data
+= strlen(dccprotos
[i
]);
175 * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid
176 * data left (== 14/13 bytes) */
177 if (parse_dcc((char *)data
, data_limit
, &dcc_ip
,
178 &dcc_port
, &addr_beg_p
, &addr_end_p
)) {
179 /* unable to parse */
180 DEBUGP("unable to parse dcc command\n");
183 DEBUGP("DCC bound ip/port: %u.%u.%u.%u:%u\n",
184 HIPQUAD(dcc_ip
), dcc_port
);
186 /* dcc_ip can be the internal OR external (NAT'ed) IP
187 * Tiago Sousa <mirage@kaotik.org> */
188 if (ct
->tuplehash
[dir
].tuple
.src
.ip
!= htonl(dcc_ip
)
189 && ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.ip
!= htonl(dcc_ip
)) {
192 "Forged DCC command from "
193 "%u.%u.%u.%u: %u.%u.%u.%u:%u\n",
194 NIPQUAD(ct
->tuplehash
[dir
].tuple
.src
.ip
),
195 HIPQUAD(dcc_ip
), dcc_port
);
200 exp
= ip_conntrack_expect_alloc(ct
);
206 /* save position of address in dcc string,
207 * necessary for NAT */
208 DEBUGP("tcph->seq = %u\n", th
->seq
);
209 seq
= ntohl(th
->seq
) + (addr_beg_p
- ib_ptr
);
211 /* We refer to the reverse direction ("!dir")
212 * tuples here, because we're expecting
213 * something in the other * direction.
214 * Doesn't matter unless NAT is happening. */
215 exp
->tuple
= ((struct ip_conntrack_tuple
)
217 { ct
->tuplehash
[!dir
].tuple
.dst
.ip
,
218 { .tcp
= { htons(dcc_port
) } },
220 exp
->mask
= ((struct ip_conntrack_tuple
)
223 { .tcp
= { htons(0xFFFF) } }, 0xFF }});
224 exp
->expectfn
= NULL
;
226 ip_nat_irc
= rcu_dereference(ip_nat_irc_hook
);
228 ret
= ip_nat_irc(pskb
, ctinfo
,
230 addr_end_p
- addr_beg_p
,
232 else if (ip_conntrack_expect_related(exp
) != 0)
234 ip_conntrack_expect_put(exp
);
236 } /* for .. NUM_DCCPROTO */
237 } /* while data < ... */
240 spin_unlock_bh(&irc_buffer_lock
);
244 static struct ip_conntrack_helper irc_helpers
[MAX_PORTS
];
245 static char irc_names
[MAX_PORTS
][sizeof("irc-65535")];
247 static void ip_conntrack_irc_fini(void);
249 static int __init
ip_conntrack_irc_init(void)
252 struct ip_conntrack_helper
*hlpr
;
255 if (max_dcc_channels
< 1) {
256 printk("ip_conntrack_irc: max_dcc_channels must be a positive integer\n");
260 irc_buffer
= kmalloc(65536, GFP_KERNEL
);
264 /* If no port given, default to standard irc port */
266 ports
[ports_c
++] = IRC_PORT
;
268 for (i
= 0; i
< ports_c
; i
++) {
269 hlpr
= &irc_helpers
[i
];
270 hlpr
->tuple
.src
.u
.tcp
.port
= htons(ports
[i
]);
271 hlpr
->tuple
.dst
.protonum
= IPPROTO_TCP
;
272 hlpr
->mask
.src
.u
.tcp
.port
= htons(0xFFFF);
273 hlpr
->mask
.dst
.protonum
= 0xFF;
274 hlpr
->max_expected
= max_dcc_channels
;
275 hlpr
->timeout
= dcc_timeout
;
276 hlpr
->me
= THIS_MODULE
;
279 tmpname
= &irc_names
[i
][0];
280 if (ports
[i
] == IRC_PORT
)
281 sprintf(tmpname
, "irc");
283 sprintf(tmpname
, "irc-%d", i
);
284 hlpr
->name
= tmpname
;
286 DEBUGP("port #%d: %d\n", i
, ports
[i
]);
288 ret
= ip_conntrack_helper_register(hlpr
);
291 printk("ip_conntrack_irc: ERROR registering port %d\n",
293 ip_conntrack_irc_fini();
300 /* This function is intentionally _NOT_ defined as __exit, because
301 * it is needed by the init function */
302 static void ip_conntrack_irc_fini(void)
305 for (i
= 0; i
< ports_c
; i
++) {
306 DEBUGP("unregistering port %d\n",
308 ip_conntrack_helper_unregister(&irc_helpers
[i
]);
313 module_init(ip_conntrack_irc_init
);
314 module_exit(ip_conntrack_irc_fini
);