--- /dev/null
+/* 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_conntrack_expect_alloc(ct);
+ if (exp == NULL) {
+ ret = NF_DROP;
+ goto out;
+ }
+ tuple = &ct->tuplehash[!dir].tuple;
+ port = htons(dcc_port);
+ nf_conntrack_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_conntrack_expect_related(exp) != 0)
+ ret = NF_DROP;
+ nf_conntrack_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].mask.src.l3num = 0xFFFF;
+ irc[i].mask.src.u.tcp.port = htons(0xFFFF);
+ irc[i].mask.dst.protonum = 0xFF;
+ 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);
git://git.onelab.eu / linux-2.6.git / blobdiff