| 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/netfilter.h> |
| 13 | #include <linux/export.h> |
| 14 | |
| 15 | #include <net/netfilter/nf_nat.h> |
| 16 | #include <net/netfilter/nf_nat_core.h> |
| 17 | #include <net/netfilter/nf_nat_l3proto.h> |
| 18 | #include <net/netfilter/nf_nat_l4proto.h> |
| 19 | |
| 20 | bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple, |
| 21 | enum nf_nat_manip_type maniptype, |
| 22 | const union nf_conntrack_man_proto *min, |
| 23 | const union nf_conntrack_man_proto *max) |
| 24 | { |
| 25 | __be16 port; |
| 26 | |
| 27 | if (maniptype == NF_NAT_MANIP_SRC) |
| 28 | port = tuple->src.u.all; |
| 29 | else |
| 30 | port = tuple->dst.u.all; |
| 31 | |
| 32 | return ntohs(port) >= ntohs(min->all) && |
| 33 | ntohs(port) <= ntohs(max->all); |
| 34 | } |
| 35 | EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range); |
| 36 | |
| 37 | void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto, |
| 38 | struct nf_conntrack_tuple *tuple, |
| 39 | const struct nf_nat_range *range, |
| 40 | enum nf_nat_manip_type maniptype, |
| 41 | const struct nf_conn *ct, |
| 42 | u16 *rover) |
| 43 | { |
| 44 | unsigned int range_size, min, i; |
| 45 | __be16 *portptr; |
| 46 | u_int16_t off; |
| 47 | |
| 48 | if (maniptype == NF_NAT_MANIP_SRC) |
| 49 | portptr = &tuple->src.u.all; |
| 50 | else |
| 51 | portptr = &tuple->dst.u.all; |
| 52 | |
| 53 | /* If no range specified... */ |
| 54 | if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) { |
| 55 | /* If it's dst rewrite, can't change port */ |
| 56 | if (maniptype == NF_NAT_MANIP_DST) |
| 57 | return; |
| 58 | |
| 59 | if (ntohs(*portptr) < 1024) { |
| 60 | /* Loose convention: >> 512 is credential passing */ |
| 61 | if (ntohs(*portptr) < 512) { |
| 62 | min = 1; |
| 63 | range_size = 511 - min + 1; |
| 64 | } else { |
| 65 | min = 600; |
| 66 | range_size = 1023 - min + 1; |
| 67 | } |
| 68 | } else { |
| 69 | min = 1024; |
| 70 | range_size = 65535 - 1024 + 1; |
| 71 | } |
| 72 | } else { |
| 73 | min = ntohs(range->min_proto.all); |
| 74 | range_size = ntohs(range->max_proto.all) - min + 1; |
| 75 | } |
| 76 | |
| 77 | if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) { |
| 78 | off = l3proto->secure_port(tuple, maniptype == NF_NAT_MANIP_SRC |
| 79 | ? tuple->dst.u.all |
| 80 | : tuple->src.u.all); |
| 81 | } else if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) { |
| 82 | off = prandom_u32(); |
| 83 | } else { |
| 84 | off = *rover; |
| 85 | } |
| 86 | |
| 87 | for (i = 0; ; ++off) { |
| 88 | *portptr = htons(min + off % range_size); |
| 89 | if (++i != range_size && nf_nat_used_tuple(tuple, ct)) |
| 90 | continue; |
| 91 | if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) |
| 92 | *rover = off; |
| 93 | return; |
| 94 | } |
| 95 | } |
| 96 | EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple); |
| 97 | |
| 98 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| 99 | int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[], |
| 100 | struct nf_nat_range *range) |
| 101 | { |
| 102 | if (tb[CTA_PROTONAT_PORT_MIN]) { |
| 103 | range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]); |
| 104 | range->max_proto.all = range->min_proto.all; |
| 105 | range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; |
| 106 | } |
| 107 | if (tb[CTA_PROTONAT_PORT_MAX]) { |
| 108 | range->max_proto.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_l4proto_nlattr_to_range); |
| 114 | #endif |