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Diffstat (limited to 'net/ipv4/netfilter/ip_conntrack_irc.c')
-rw-r--r--net/ipv4/netfilter/ip_conntrack_irc.c313
1 files changed, 313 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ip_conntrack_irc.c b/net/ipv4/netfilter/ip_conntrack_irc.c
new file mode 100644
index 00000000000..33cc7348b6e
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+++ b/net/ipv4/netfilter/ip_conntrack_irc.c
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+/* 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
+ *
+ * ip_conntrack_irc.c,v 1.21 2002/02/05 14:49:26 laforge Exp
+ *
+ * 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_irc.o ports=port1,port2,...port<MAX_PORTS>
+ * max_dcc_channels=n dcc_timeout=secs
+ *
+ * please give the ports of all IRC servers You wish to connect to.
+ * If You don't specify ports, the default will be port 6667.
+ * With max_dcc_channels you can define the maximum number of not
+ * yet answered DCC channels per IRC session (default 8).
+ * With dcc_timeout you can specify how long the system waits for
+ * an expected DCC channel (default 300 seconds).
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <net/checksum.h>
+#include <net/tcp.h>
+
+#include <linux/netfilter_ipv4/lockhelp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_irc.h>
+#include <linux/moduleparam.h>
+
+#define MAX_PORTS 8
+static int ports[MAX_PORTS];
+static int ports_c;
+static int max_dcc_channels = 8;
+static unsigned int dcc_timeout = 300;
+/* This is slow, but it's simple. --RR */
+static char irc_buffer[65536];
+static DECLARE_LOCK(irc_buffer_lock);
+
+unsigned int (*ip_nat_irc_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_irc_hook);
+
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
+MODULE_LICENSE("GPL");
+module_param_array(ports, int, &ports_c, 0400);
+MODULE_PARM_DESC(ports, "port numbers of IRC servers");
+module_param(max_dcc_channels, int, 0400);
+MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per IRC session");
+module_param(dcc_timeout, int, 0400);
+MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels");
+
+static 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
+
+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)
+/* 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 */
+{
+
+ /* 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,
+ struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
+{
+ unsigned int dataoff;
+ struct tcphdr _tcph, *th;
+ char *data, *data_limit, *ib_ptr;
+ int dir = CTINFO2DIR(ctinfo);
+ struct ip_conntrack_expect *exp;
+ u32 seq;
+ u_int32_t dcc_ip;
+ u_int16_t dcc_port;
+ int i, ret = NF_ACCEPT;
+ char *addr_beg_p, *addr_end_p;
+
+ DEBUGP("entered\n");
+
+ /* 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) {
+ DEBUGP("Conntrackinfo = %u\n", ctinfo);
+ return NF_ACCEPT;
+ }
+
+ /* Not a full tcp header? */
+ th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4,
+ sizeof(_tcph), &_tcph);
+ if (th == NULL)
+ return NF_ACCEPT;
+
+ /* No data? */
+ dataoff = (*pskb)->nh.iph->ihl*4 + th->doff*4;
+ if (dataoff >= (*pskb)->len)
+ return NF_ACCEPT;
+
+ 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;
+ }
+
+ DEBUGP("DCC %s detected\n", dccprotos[i]);
+ data += strlen(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)) {
+ /* unable to parse */
+ 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
+ * Tiago Sousa <mirage@kaotik.org> */
+ if (ct->tuplehash[dir].tuple.src.ip != htonl(dcc_ip)
+ && ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.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(ct->tuplehash[dir].tuple.src.ip),
+ HIPQUAD(dcc_ip), dcc_port);
+
+ continue;
+ }
+
+ exp = ip_conntrack_expect_alloc();
+ if (exp == NULL) {
+ ret = NF_DROP;
+ goto out;
+ }
+
+ /* save position of address in dcc string,
+ * necessary for NAT */
+ DEBUGP("tcph->seq = %u\n", th->seq);
+ seq = ntohl(th->seq) + (addr_beg_p - ib_ptr);
+
+ /* We refer to the reverse direction ("!dir")
+ * tuples here, because we're expecting
+ * something in the other * direction.
+ * Doesn't matter unless NAT is happening. */
+ exp->tuple = ((struct ip_conntrack_tuple)
+ { { 0, { 0 } },
+ { ct->tuplehash[!dir].tuple.dst.ip,
+ { .tcp = { htons(dcc_port) } },
+ IPPROTO_TCP }});
+ exp->mask = ((struct ip_conntrack_tuple)
+ { { 0, { 0 } },
+ { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFF }});
+ exp->expectfn = NULL;
+ exp->master = ct;
+ if (ip_nat_irc_hook)
+ ret = ip_nat_irc_hook(pskb, ctinfo,
+ addr_beg_p - ib_ptr,
+ addr_end_p - addr_beg_p,
+ exp);
+ else if (ip_conntrack_expect_related(exp) != 0) {
+ ip_conntrack_expect_free(exp);
+ ret = NF_DROP;
+ }
+ goto out;
+ } /* for .. NUM_DCCPROTO */
+ } /* while data < ... */
+
+ out:
+ UNLOCK_BH(&irc_buffer_lock);
+ return ret;
+}
+
+static struct ip_conntrack_helper irc_helpers[MAX_PORTS];
+static char irc_names[MAX_PORTS][10];
+
+static void fini(void);
+
+static int __init init(void)
+{
+ int i, ret;
+ struct ip_conntrack_helper *hlpr;
+ char *tmpname;
+
+ if (max_dcc_channels < 1) {
+ printk("ip_conntrack_irc: max_dcc_channels must be a positive integer\n");
+ return -EBUSY;
+ }
+ if (dcc_timeout < 0) {
+ printk("ip_conntrack_irc: dcc_timeout must be a positive integer\n");
+ return -EBUSY;
+ }
+
+ /* 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++) {
+ hlpr = &irc_helpers[i];
+ hlpr->tuple.src.u.tcp.port = htons(ports[i]);
+ hlpr->tuple.dst.protonum = IPPROTO_TCP;
+ hlpr->mask.src.u.tcp.port = 0xFFFF;
+ hlpr->mask.dst.protonum = 0xFF;
+ hlpr->max_expected = max_dcc_channels;
+ hlpr->timeout = dcc_timeout;
+ hlpr->me = THIS_MODULE;
+ hlpr->help = help;
+
+ tmpname = &irc_names[i][0];
+ if (ports[i] == IRC_PORT)
+ sprintf(tmpname, "irc");
+ else
+ sprintf(tmpname, "irc-%d", i);
+ hlpr->name = tmpname;
+
+ DEBUGP("port #%d: %d\n", i, ports[i]);
+
+ ret = ip_conntrack_helper_register(hlpr);
+
+ if (ret) {
+ printk("ip_conntrack_irc: ERROR registering port %d\n",
+ ports[i]);
+ fini();
+ return -EBUSY;
+ }
+ }
+ return 0;
+}
+
+/* This function is intentionally _NOT_ defined as __exit, because
+ * it is needed by the init function */
+static void fini(void)
+{
+ int i;
+ for (i = 0; i < ports_c; i++) {
+ DEBUGP("unregistering port %d\n",
+ ports[i]);
+ ip_conntrack_helper_unregister(&irc_helpers[i]);
+ }
+}
+
+module_init(init);
+module_exit(fini);