1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2008 Patrick McHardy <kaber@trash.net>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/types.h>
11 #include <linux/random.h>
12 #include <linux/ip.h>
13
14 #include <linux/netfilter.h>
15 #include <linux/export.h>
16 #include <net/secure_seq.h>
17 #include <net/netfilter/nf_nat.h>
18 #include <net/netfilter/nf_nat_core.h>
19 #include <net/netfilter/nf_nat_rule.h>
20 #include <net/netfilter/nf_nat_protocol.h>
21
nf_nat_proto_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)22 bool nf_nat_proto_in_range(const struct nf_conntrack_tuple *tuple,
23 enum nf_nat_manip_type maniptype,
24 const union nf_conntrack_man_proto *min,
25 const union nf_conntrack_man_proto *max)
26 {
27 __be16 port;
28
29 if (maniptype == NF_NAT_MANIP_SRC)
30 port = tuple->src.u.all;
31 else
32 port = tuple->dst.u.all;
33
34 return ntohs(port) >= ntohs(min->all) &&
35 ntohs(port) <= ntohs(max->all);
36 }
37 EXPORT_SYMBOL_GPL(nf_nat_proto_in_range);
38
nf_nat_proto_unique_tuple(struct nf_conntrack_tuple * tuple,const struct nf_nat_ipv4_range * range,enum nf_nat_manip_type maniptype,const struct nf_conn * ct,u_int16_t * rover)39 void nf_nat_proto_unique_tuple(struct nf_conntrack_tuple *tuple,
40 const struct nf_nat_ipv4_range *range,
41 enum nf_nat_manip_type maniptype,
42 const struct nf_conn *ct,
43 u_int16_t *rover)
44 {
45 unsigned int range_size, min, i;
46 __be16 *portptr;
47 u_int16_t off;
48
49 if (maniptype == NF_NAT_MANIP_SRC)
50 portptr = &tuple->src.u.all;
51 else
52 portptr = &tuple->dst.u.all;
53
54 /* If no range specified... */
55 if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
56 /* If it's dst rewrite, can't change port */
57 if (maniptype == NF_NAT_MANIP_DST)
58 return;
59
60 if (ntohs(*portptr) < 1024) {
61 /* Loose convention: >> 512 is credential passing */
62 if (ntohs(*portptr) < 512) {
63 min = 1;
64 range_size = 511 - min + 1;
65 } else {
66 min = 600;
67 range_size = 1023 - min + 1;
68 }
69 } else {
70 min = 1024;
71 range_size = 65535 - 1024 + 1;
72 }
73 } else {
74 min = ntohs(range->min.all);
75 range_size = ntohs(range->max.all) - min + 1;
76 }
77
78 if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
79 off = secure_ipv4_port_ephemeral(tuple->src.u3.ip, tuple->dst.u3.ip,
80 maniptype == NF_NAT_MANIP_SRC
81 ? tuple->dst.u.all
82 : tuple->src.u.all);
83 else
84 off = *rover;
85
86 for (i = 0; ; ++off) {
87 *portptr = htons(min + off % range_size);
88 if (++i != range_size && nf_nat_used_tuple(tuple, ct))
89 continue;
90 if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM))
91 *rover = off;
92 return;
93 }
94 return;
95 }
96 EXPORT_SYMBOL_GPL(nf_nat_proto_unique_tuple);
97
98 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
nf_nat_proto_nlattr_to_range(struct nlattr * tb[],struct nf_nat_ipv4_range * range)99 int nf_nat_proto_nlattr_to_range(struct nlattr *tb[],
100 struct nf_nat_ipv4_range *range)
101 {
102 if (tb[CTA_PROTONAT_PORT_MIN]) {
103 range->min.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
104 range->max.all = range->min.tcp.port;
105 range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
106 }
107 if (tb[CTA_PROTONAT_PORT_MAX]) {
108 range->max.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
109 range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
110 }
111 return 0;
112 }
113 EXPORT_SYMBOL_GPL(nf_nat_proto_nlattr_to_range);
114 #endif
115