[NETFILTER]: nf_conntrack/nf_nat: add IRC helper port
Add nf_conntrack port of the IRC conntrack/NAT helper. Since DCC doesn't
support IPv6 yet, the helper is still IPv4 only.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_irc.c b/net/ipv4/netfilter/nf_nat_irc.c
new file mode 100644
index 0000000..9b8c0da
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_irc.c
@@ -0,0 +1,101 @@
+/* IRC extension for TCP NAT alteration.
+ *
+ * (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2004 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ * based on a copy of RR's ip_nat_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/tcp.h>
+#include <linux/kernel.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <linux/netfilter/nf_conntrack_irc.h>
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("IRC (DCC) NAT helper");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ip_nat_irc");
+
+static unsigned int help(struct sk_buff **pskb,
+ enum ip_conntrack_info ctinfo,
+ unsigned int matchoff,
+ unsigned int matchlen,
+ struct nf_conntrack_expect *exp)
+{
+ char buffer[sizeof("4294967296 65635")];
+ u_int32_t ip;
+ u_int16_t port;
+ unsigned int ret;
+
+ DEBUGP("IRC_NAT: info (seq %u + %u) in %u\n",
+ expect->seq, exp_irc_info->len, ntohl(tcph->seq));
+
+ /* Reply comes from server. */
+ exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
+ exp->dir = IP_CT_DIR_REPLY;
+ exp->expectfn = nf_nat_follow_master;
+
+ /* Try to get same port: if not, try to change it. */
+ for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
+ exp->tuple.dst.u.tcp.port = htons(port);
+ if (nf_conntrack_expect_related(exp) == 0)
+ break;
+ }
+
+ if (port == 0)
+ return NF_DROP;
+
+ ip = ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip);
+ sprintf(buffer, "%u %u", ip, port);
+ DEBUGP("nf_nat_irc: inserting '%s' == %u.%u.%u.%u, port %u\n",
+ buffer, NIPQUAD(ip), port);
+
+ ret = nf_nat_mangle_tcp_packet(pskb, exp->master, ctinfo,
+ matchoff, matchlen, buffer,
+ strlen(buffer));
+ if (ret != NF_ACCEPT)
+ nf_conntrack_unexpect_related(exp);
+ return ret;
+}
+
+static void __exit nf_nat_irc_fini(void)
+{
+ rcu_assign_pointer(nf_nat_irc_hook, NULL);
+ synchronize_rcu();
+}
+
+static int __init nf_nat_irc_init(void)
+{
+ BUG_ON(rcu_dereference(nf_nat_irc_hook));
+ rcu_assign_pointer(nf_nat_irc_hook, help);
+ return 0;
+}
+
+/* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
+static int warn_set(const char *val, struct kernel_param *kp)
+{
+ printk(KERN_INFO KBUILD_MODNAME
+ ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
+ return 0;
+}
+module_param_call(ports, warn_set, NULL, NULL, 0);
+
+module_init(nf_nat_irc_init);
+module_exit(nf_nat_irc_fini);