netfilter: nf_nat: support IPv6 in IRC NAT helper

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

4 files changed, 100 insertions, 2 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index bf3e4649efb2..cabe4da0e191 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -390,6 +390,11 @@ config NF_NAT_FTP
 	depends on NF_CONNTRACK && NF_NAT
 	default NF_NAT && NF_CONNTRACK_FTP
 
+config NF_NAT_IRC
+	tristate
+	depends on NF_CONNTRACK && NF_NAT
+	default NF_NAT && NF_CONNTRACK_IRC
+
 config NF_NAT_SIP
 	tristate
 	depends on NF_CONNTRACK && NF_NAT
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 7d6d1a035f31..0dd792972cae 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_NF_NAT_PROTO_SCTP) += nf_nat_proto_sctp.o
 # NAT helpers
 obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o
 obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
+obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
 obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
 
 # transparent proxy support
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c
index 95d097cdb202..3b20aa77cfc8 100644
--- a/net/netfilter/nf_conntrack_irc.c
+++ b/net/netfilter/nf_conntrack_irc.c
@@ -205,8 +205,7 @@ static int help(struct sk_buff *skb, unsigned int protoff,
 					  IPPROTO_TCP, NULL, &port);
 
 			nf_nat_irc = rcu_dereference(nf_nat_irc_hook);
-			if (nf_nat_irc && nf_ct_l3num(ct) == NFPROTO_IPV4 &&
-			    ct->status & IPS_NAT_MASK)
+			if (nf_nat_irc && ct->status & IPS_NAT_MASK)
 				ret = nf_nat_irc(skb, ctinfo, protoff,
 						 addr_beg_p - ib_ptr,
 						 addr_end_p - addr_beg_p,
diff --git a/net/netfilter/nf_nat_irc.c b/net/netfilter/nf_nat_irc.c
new file mode 100644
index 000000000000..1fedee6e7fb6
--- /dev/null
+++ b/net/netfilter/nf_nat_irc.c
@@ -0,0 +1,93 @@
+/* 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_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <linux/netfilter/nf_conntrack_irc.h>
+
+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 *skb,
+			 enum ip_conntrack_info ctinfo,
+			 unsigned int protoff,
+			 unsigned int matchoff,
+			 unsigned int matchlen,
+			 struct nf_conntrack_expect *exp)
+{
+	char buffer[sizeof("4294967296 65635")];
+	u_int16_t port;
+	unsigned int ret;
+
+	/* 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++) {
+		int ret;
+
+		exp->tuple.dst.u.tcp.port = htons(port);
+		ret = nf_ct_expect_related(exp);
+		if (ret == 0)
+			break;
+		else if (ret != -EBUSY) {
+			port = 0;
+			break;
+		}
+	}
+
+	if (port == 0)
+		return NF_DROP;
+
+	ret = nf_nat_mangle_tcp_packet(skb, exp->master, ctinfo,
+				       protoff, matchoff, matchlen, buffer,
+				       strlen(buffer));
+	if (ret != NF_ACCEPT)
+		nf_ct_unexpect_related(exp);
+	return ret;
+}
+
+static void __exit nf_nat_irc_fini(void)
+{
+	RCU_INIT_POINTER(nf_nat_irc_hook, NULL);
+	synchronize_rcu();
+}
+
+static int __init nf_nat_irc_init(void)
+{
+	BUG_ON(nf_nat_irc_hook != NULL);
+	RCU_INIT_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);