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net/netfilter/nf_nat_proto_common.c
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/* (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, max, 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); 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 { 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 |