| /* (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_range2 *range, |
| enum nf_nat_manip_type maniptype, |
| const struct nf_conn *ct) |
| { |
| unsigned int range_size, min, max, i, attempts; |
| __be16 *portptr; |
| u16 off; |
| static const unsigned int max_attempts = 128; |
| |
| 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); |
| max = ntohs(range->max_proto.all); |
| if (unlikely(max < min)) |
| swap(max, min); |
| range_size = max - 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 if (range->flags & NF_NAT_RANGE_PROTO_OFFSET) { |
| off = (ntohs(*portptr) - ntohs(range->base_proto.all)); |
| } else { |
| off = prandom_u32(); |
| } |
| |
| attempts = range_size; |
| if (attempts > max_attempts) |
| attempts = max_attempts; |
| |
| /* We are in softirq; doing a search of the entire range risks |
| * soft lockup when all tuples are already used. |
| * |
| * If we can't find any free port from first offset, pick a new |
| * one and try again, with ever smaller search window. |
| */ |
| another_round: |
| for (i = 0; i < attempts; i++, off++) { |
| *portptr = htons(min + off % range_size); |
| if (!nf_nat_used_tuple(tuple, ct)) |
| return; |
| } |
| |
| if (attempts >= range_size || attempts < 16) |
| return; |
| attempts /= 2; |
| off = prandom_u32(); |
| goto another_round; |
| } |
| 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_range2 *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 |