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