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>
37 static int ports[MAX_PORTS];
39 static int max_dcc_channels = 8;
40 static unsigned int dcc_timeout = 300;
41 /* This is slow, but it's simple. --RR */
42 static char irc_buffer[65536];
44 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
45 MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
46 MODULE_LICENSE("GPL");
47 MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_PORTS) "i");
48 MODULE_PARM_DESC(ports, "port numbers of IRC servers");
49 MODULE_PARM(max_dcc_channels, "i");
50 MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per IRC session");
51 MODULE_PARM(dcc_timeout, "i");
52 MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels");
54 static char *dccprotos[] = { "SEND ", "CHAT ", "MOVE ", "TSEND ", "SCHAT " };
57 DECLARE_LOCK(ip_irc_lock);
58 struct module *ip_conntrack_irc = THIS_MODULE;
61 #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s:" format, \
62 __FILE__, __FUNCTION__ , ## args)
64 #define DEBUGP(format, args...)
67 int parse_dcc(char *data, char *data_end, u_int32_t * ip, u_int16_t * port,
68 char **ad_beg_p, char **ad_end_p)
69 /* tries to get the ip_addr and port out of a dcc command
70 return value: -1 on failure, 0 on success
71 data pointer to first byte of DCC command data
72 data_end pointer to last byte of dcc command data
73 ip returns parsed ip of dcc command
74 port returns parsed port of dcc command
75 ad_beg_p returns pointer to first byte of addr data
76 ad_end_p returns pointer to last byte of addr data */
79 /* at least 12: "AAAAAAAA P\1\n" */
80 while (*data++ != ' ')
81 if (data > data_end - 12)
85 *ip = simple_strtoul(data, &data, 10);
87 /* skip blanks between ip and port */
88 while (*data == ' ') {
94 *port = simple_strtoul(data, &data, 10);
100 static int help(struct sk_buff *skb,
101 struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
103 unsigned int dataoff;
105 char *data, *data_limit;
106 int dir = CTINFO2DIR(ctinfo);
107 struct ip_conntrack_expect *exp;
108 struct ip_ct_irc_expect *exp_irc_info = NULL;
113 char *addr_beg_p, *addr_end_p;
117 /* If packet is coming from IRC server */
118 if (dir == IP_CT_DIR_REPLY)
121 /* Until there's been traffic both ways, don't look in packets. */
122 if (ctinfo != IP_CT_ESTABLISHED
123 && ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
124 DEBUGP("Conntrackinfo = %u\n", ctinfo);
128 /* Not a full tcp header? */
129 if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &tcph, sizeof(tcph)) != 0)
133 dataoff = skb->nh.iph->ihl*4 + tcph.doff*4;
134 if (dataoff >= skb->len)
137 LOCK_BH(&ip_irc_lock);
138 skb_copy_bits(skb, dataoff, irc_buffer, skb->len - dataoff);
141 data_limit = irc_buffer + skb->len - dataoff;
143 /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
144 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
145 while (data < (data_limit - (19 + MINMATCHLEN))) {
146 if (memcmp(data, "\1DCC ", 5)) {
152 /* we have at least (19+MINMATCHLEN)-5 bytes valid data left */
154 DEBUGP("DCC found in master %u.%u.%u.%u:%u %u.%u.%u.%u:%u...\n",
155 NIPQUAD(iph->saddr), ntohs(tcph.source),
156 NIPQUAD(iph->daddr), ntohs(tcph.dest));
158 for (i = 0; i < ARRAY_SIZE(dccprotos); i++) {
159 if (memcmp(data, dccprotos[i], strlen(dccprotos[i]))) {
164 DEBUGP("DCC %s detected\n", dccprotos[i]);
165 data += strlen(dccprotos[i]);
167 * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid
168 * data left (== 14/13 bytes) */
169 if (parse_dcc((char *)data, data_limit, &dcc_ip,
170 &dcc_port, &addr_beg_p, &addr_end_p)) {
171 /* unable to parse */
172 DEBUGP("unable to parse dcc command\n");
175 DEBUGP("DCC bound ip/port: %u.%u.%u.%u:%u\n",
176 HIPQUAD(dcc_ip), dcc_port);
178 /* dcc_ip can be the internal OR external (NAT'ed) IP
179 * Tiago Sousa <mirage@kaotik.org> */
180 if (ct->tuplehash[dir].tuple.src.ip != htonl(dcc_ip)
181 && ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip != htonl(dcc_ip)) {
184 "Forged DCC command from "
185 "%u.%u.%u.%u: %u.%u.%u.%u:%u\n",
186 NIPQUAD(ct->tuplehash[dir].tuple.src.ip),
187 HIPQUAD(dcc_ip), dcc_port);
192 exp = ip_conntrack_expect_alloc();
196 exp_irc_info = &exp->help.exp_irc_info;
198 /* save position of address in dcc string,
199 * necessary for NAT */
200 DEBUGP("tcph->seq = %u\n", tcph.seq);
201 exp->seq = ntohl(tcph.seq) + (addr_beg_p - irc_buffer);
202 exp_irc_info->len = (addr_end_p - addr_beg_p);
203 exp_irc_info->port = dcc_port;
204 DEBUGP("wrote info seq=%u (ofs=%u), len=%d\n",
205 exp->seq, (addr_end_p - _data), exp_irc_info->len);
207 exp->tuple = ((struct ip_conntrack_tuple)
209 { ct->tuplehash[dir].tuple.src.ip, { .tcp = { htons(dcc_port) } },
211 exp->mask = ((struct ip_conntrack_tuple)
213 { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFFFF }});
215 exp->expectfn = NULL;
217 DEBUGP("expect_related %u.%u.%u.%u:%u-%u.%u.%u.%u:%u\n",
218 NIPQUAD(exp->tuple.src.ip),
219 ntohs(exp->tuple.src.u.tcp.port),
220 NIPQUAD(exp->tuple.dst.ip),
221 ntohs(exp->tuple.dst.u.tcp.port));
223 ip_conntrack_expect_related(exp, ct);
226 } /* for .. NUM_DCCPROTO */
227 } /* while data < ... */
230 UNLOCK_BH(&ip_irc_lock);
234 static struct ip_conntrack_helper irc_helpers[MAX_PORTS];
235 static char irc_names[MAX_PORTS][10];
237 static void fini(void);
239 static int __init init(void)
242 struct ip_conntrack_helper *hlpr;
245 if (max_dcc_channels < 1) {
246 printk("ip_conntrack_irc: max_dcc_channels must be a positive integer\n");
249 if (dcc_timeout < 0) {
250 printk("ip_conntrack_irc: dcc_timeout must be a positive integer\n");
254 /* If no port given, default to standard irc port */
258 for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
259 hlpr = &irc_helpers[i];
260 hlpr->tuple.src.u.tcp.port = htons(ports[i]);
261 hlpr->tuple.dst.protonum = IPPROTO_TCP;
262 hlpr->mask.src.u.tcp.port = 0xFFFF;
263 hlpr->mask.dst.protonum = 0xFFFF;
264 hlpr->max_expected = max_dcc_channels;
265 hlpr->timeout = dcc_timeout;
266 hlpr->flags = IP_CT_HELPER_F_REUSE_EXPECT;
267 hlpr->me = ip_conntrack_irc;
270 tmpname = &irc_names[i][0];
271 if (ports[i] == IRC_PORT)
272 sprintf(tmpname, "irc");
274 sprintf(tmpname, "irc-%d", i);
275 hlpr->name = tmpname;
277 DEBUGP("port #%d: %d\n", i, ports[i]);
279 ret = ip_conntrack_helper_register(hlpr);
282 printk("ip_conntrack_irc: ERROR registering port %d\n",
292 /* This function is intentionally _NOT_ defined as __exit, because
293 * it is needed by the init function */
294 static void fini(void)
297 for (i = 0; i < ports_c; i++) {
298 DEBUGP("unregistering port %d\n",
300 ip_conntrack_helper_unregister(&irc_helpers[i]);
304 PROVIDES_CONNTRACK(irc);
305 EXPORT_SYMBOL(ip_irc_lock);