From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 net/netfilter/nf_nat_proto_common.c | 114 ++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 net/netfilter/nf_nat_proto_common.c

(limited to 'net/netfilter/nf_nat_proto_common.c')

diff --git a/net/netfilter/nf_nat_proto_common.c b/net/netfilter/nf_nat_proto_common.c
new file mode 100644
index 000000000..fbce552a7
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_common.c
@@ -0,0 +1,114 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/random.h>
+#include <linux/netfilter.h>
+#include <linux/export.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
+			     enum nf_nat_manip_type maniptype,
+			     const union nf_conntrack_man_proto *min,
+			     const union nf_conntrack_man_proto *max)
+{
+	__be16 port;
+
+	if (maniptype == NF_NAT_MANIP_SRC)
+		port = tuple->src.u.all;
+	else
+		port = tuple->dst.u.all;
+
+	return ntohs(port) >= ntohs(min->all) &&
+	       ntohs(port) <= ntohs(max->all);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range);
+
+void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
+				 struct nf_conntrack_tuple *tuple,
+				 const struct nf_nat_range *range,
+				 enum nf_nat_manip_type maniptype,
+				 const struct nf_conn *ct,
+				 u16 *rover)
+{
+	unsigned int range_size, min, i;
+	__be16 *portptr;
+	u_int16_t off;
+
+	if (maniptype == NF_NAT_MANIP_SRC)
+		portptr = &tuple->src.u.all;
+	else
+		portptr = &tuple->dst.u.all;
+
+	/* If no range specified... */
+	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
+		/* If it's dst rewrite, can't change port */
+		if (maniptype == NF_NAT_MANIP_DST)
+			return;
+
+		if (ntohs(*portptr) < 1024) {
+			/* Loose convention: >> 512 is credential passing */
+			if (ntohs(*portptr) < 512) {
+				min = 1;
+				range_size = 511 - min + 1;
+			} else {
+				min = 600;
+				range_size = 1023 - min + 1;
+			}
+		} else {
+			min = 1024;
+			range_size = 65535 - 1024 + 1;
+		}
+	} else {
+		min = ntohs(range->min_proto.all);
+		range_size = ntohs(range->max_proto.all) - min + 1;
+	}
+
+	if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) {
+		off = l3proto->secure_port(tuple, maniptype == NF_NAT_MANIP_SRC
+						  ? tuple->dst.u.all
+						  : tuple->src.u.all);
+	} else if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) {
+		off = prandom_u32();
+	} else {
+		off = *rover;
+	}
+
+	for (i = 0; ; ++off) {
+		*portptr = htons(min + off % range_size);
+		if (++i != range_size && nf_nat_used_tuple(tuple, ct))
+			continue;
+		if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL))
+			*rover = off;
+		return;
+	}
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple);
+
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
+int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
+				   struct nf_nat_range *range)
+{
+	if (tb[CTA_PROTONAT_PORT_MIN]) {
+		range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
+		range->max_proto.all = range->min_proto.all;
+		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+	}
+	if (tb[CTA_PROTONAT_PORT_MAX]) {
+		range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
+		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_nlattr_to_range);
+#endif
-- 
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