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/config.h>
26 #include <linux/module.h>
27 #include <linux/netfilter.h>
29 #include <net/checksum.h>
32 #include <linux/netfilter_ipv4/lockhelp.h>
33 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
34 #include <linux/netfilter_ipv4/ip_conntrack_irc.h>
35 #include <linux/moduleparam.h>
38 static int ports[MAX_PORTS];
40 static int max_dcc_channels = 8;
41 static unsigned int dcc_timeout = 300;
42 /* This is slow, but it's simple. --RR */
43 static char irc_buffer[65536];
44 static DECLARE_LOCK(irc_buffer_lock);
46 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
47 MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
48 MODULE_LICENSE("GPL");
49 module_param_array(ports, int, &ports_c, 0400);
50 MODULE_PARM_DESC(ports, "port numbers of IRC servers");
51 module_param(max_dcc_channels, int, 0400);
52 MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per IRC session");
53 module_param(dcc_timeout, int, 0400);
54 MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels");
56 static char *dccprotos[] = { "SEND ", "CHAT ", "MOVE ", "TSEND ", "SCHAT " };
59 struct module *ip_conntrack_irc = THIS_MODULE;
62 #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s:" format, \
63 __FILE__, __FUNCTION__ , ## args)
65 #define DEBUGP(format, args...)
68 static int parse_dcc(char *data, char *data_end, u_int32_t *ip,
69 u_int16_t *port, char **ad_beg_p, char **ad_end_p)
70 /* tries to get the ip_addr and port out of a dcc command
71 return value: -1 on failure, 0 on success
72 data pointer to first byte of DCC command data
73 data_end pointer to last byte of dcc command data
74 ip returns parsed ip of dcc command
75 port returns parsed port of dcc command
76 ad_beg_p returns pointer to first byte of addr data
77 ad_end_p returns pointer to last byte of addr data */
80 /* at least 12: "AAAAAAAA P\1\n" */
81 while (*data++ != ' ')
82 if (data > data_end - 12)
86 *ip = simple_strtoul(data, &data, 10);
88 /* skip blanks between ip and port */
89 while (*data == ' ') {
95 *port = simple_strtoul(data, &data, 10);
101 static int help(struct sk_buff *skb,
102 struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
104 unsigned int dataoff;
105 struct tcphdr _tcph, *th;
106 char *data, *data_limit, *ib_ptr;
107 int dir = CTINFO2DIR(ctinfo);
108 struct ip_conntrack_expect *exp;
109 struct ip_ct_irc_expect *exp_irc_info = NULL;
114 char *addr_beg_p, *addr_end_p;
118 /* If packet is coming from IRC server */
119 if (dir == IP_CT_DIR_REPLY)
122 /* Until there's been traffic both ways, don't look in packets. */
123 if (ctinfo != IP_CT_ESTABLISHED
124 && ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
125 DEBUGP("Conntrackinfo = %u\n", ctinfo);
129 /* Not a full tcp header? */
130 th = skb_header_pointer(skb, skb->nh.iph->ihl*4,
131 sizeof(_tcph), &_tcph);
136 dataoff = skb->nh.iph->ihl*4 + th->doff*4;
137 if (dataoff >= skb->len)
140 LOCK_BH(&irc_buffer_lock);
141 ib_ptr = skb_header_pointer(skb, dataoff,
142 skb->len - dataoff, irc_buffer);
143 BUG_ON(ib_ptr == NULL);
146 data_limit = ib_ptr + skb->len - dataoff;
148 /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
149 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
150 while (data < (data_limit - (19 + MINMATCHLEN))) {
151 if (memcmp(data, "\1DCC ", 5)) {
157 /* we have at least (19+MINMATCHLEN)-5 bytes valid data left */
159 DEBUGP("DCC found in master %u.%u.%u.%u:%u %u.%u.%u.%u:%u...\n",
160 NIPQUAD(iph->saddr), ntohs(th->source),
161 NIPQUAD(iph->daddr), ntohs(th->dest));
163 for (i = 0; i < ARRAY_SIZE(dccprotos); i++) {
164 if (memcmp(data, dccprotos[i], strlen(dccprotos[i]))) {
169 DEBUGP("DCC %s detected\n", dccprotos[i]);
170 data += strlen(dccprotos[i]);
172 * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid
173 * data left (== 14/13 bytes) */
174 if (parse_dcc((char *)data, data_limit, &dcc_ip,
175 &dcc_port, &addr_beg_p, &addr_end_p)) {
176 /* unable to parse */
177 DEBUGP("unable to parse dcc command\n");
180 DEBUGP("DCC bound ip/port: %u.%u.%u.%u:%u\n",
181 HIPQUAD(dcc_ip), dcc_port);
183 /* dcc_ip can be the internal OR external (NAT'ed) IP
184 * Tiago Sousa <mirage@kaotik.org> */
185 if (ct->tuplehash[dir].tuple.src.ip != htonl(dcc_ip)
186 && ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip != htonl(dcc_ip)) {
189 "Forged DCC command from "
190 "%u.%u.%u.%u: %u.%u.%u.%u:%u\n",
191 NIPQUAD(ct->tuplehash[dir].tuple.src.ip),
192 HIPQUAD(dcc_ip), dcc_port);
197 exp = ip_conntrack_expect_alloc();
201 exp_irc_info = &exp->help.exp_irc_info;
203 /* save position of address in dcc string,
204 * necessary for NAT */
205 DEBUGP("tcph->seq = %u\n", th->seq);
206 exp->seq = ntohl(th->seq) + (addr_beg_p - ib_ptr);
207 exp_irc_info->len = (addr_end_p - addr_beg_p);
208 exp_irc_info->port = dcc_port;
209 DEBUGP("wrote info seq=%u (ofs=%u), len=%d\n",
210 exp->seq, (addr_end_p - _data), exp_irc_info->len);
212 exp->tuple = ((struct ip_conntrack_tuple)
214 { ct->tuplehash[dir].tuple.src.ip, { .tcp = { htons(dcc_port) } },
216 exp->mask = ((struct ip_conntrack_tuple)
218 { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFFFF }});
220 exp->expectfn = NULL;
222 DEBUGP("expect_related %u.%u.%u.%u:%u-%u.%u.%u.%u:%u\n",
223 NIPQUAD(exp->tuple.src.ip),
224 ntohs(exp->tuple.src.u.tcp.port),
225 NIPQUAD(exp->tuple.dst.ip),
226 ntohs(exp->tuple.dst.u.tcp.port));
228 ip_conntrack_expect_related(exp, ct);
231 } /* for .. NUM_DCCPROTO */
232 } /* while data < ... */
235 UNLOCK_BH(&irc_buffer_lock);
239 static struct ip_conntrack_helper irc_helpers[MAX_PORTS];
240 static char irc_names[MAX_PORTS][10];
242 static void fini(void);
244 static int __init init(void)
247 struct ip_conntrack_helper *hlpr;
250 if (max_dcc_channels < 1) {
251 printk("ip_conntrack_irc: max_dcc_channels must be a positive integer\n");
254 if (dcc_timeout < 0) {
255 printk("ip_conntrack_irc: dcc_timeout must be a positive integer\n");
259 /* If no port given, default to standard irc port */
261 ports[ports_c++] = IRC_PORT;
263 for (i = 0; i < ports_c; i++) {
264 hlpr = &irc_helpers[i];
265 hlpr->tuple.src.u.tcp.port = htons(ports[i]);
266 hlpr->tuple.dst.protonum = IPPROTO_TCP;
267 hlpr->mask.src.u.tcp.port = 0xFFFF;
268 hlpr->mask.dst.protonum = 0xFFFF;
269 hlpr->max_expected = max_dcc_channels;
270 hlpr->timeout = dcc_timeout;
271 hlpr->flags = IP_CT_HELPER_F_REUSE_EXPECT;
272 hlpr->me = ip_conntrack_irc;
275 tmpname = &irc_names[i][0];
276 if (ports[i] == IRC_PORT)
277 sprintf(tmpname, "irc");
279 sprintf(tmpname, "irc-%d", i);
280 hlpr->name = tmpname;
282 DEBUGP("port #%d: %d\n", i, ports[i]);
284 ret = ip_conntrack_helper_register(hlpr);
287 printk("ip_conntrack_irc: ERROR registering port %d\n",
296 /* This function is intentionally _NOT_ defined as __exit, because
297 * it is needed by the init function */
298 static void fini(void)
301 for (i = 0; i < ports_c; i++) {
302 DEBUGP("unregistering port %d\n",
304 ip_conntrack_helper_unregister(&irc_helpers[i]);
308 PROVIDES_CONNTRACK(irc);