include/net/netfilter/nf_nat.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NF_NAT_H
   3 #define _NF_NAT_H
   4 #include <linux/netfilter_ipv4.h>
   5 #include <linux/netfilter/nf_nat.h>
   6 #include <net/netfilter/nf_conntrack_tuple.h>
   7
   8 enum nf_nat_manip_type {
   9         NF_NAT_MANIP_SRC,
  10         NF_NAT_MANIP_DST
  11 };
  12
  13 /* SRC manip occurs POST_ROUTING or LOCAL_IN */
  14 #define HOOK2MANIP(hooknum) ((hooknum) != NF_INET_POST_ROUTING && \
  15                              (hooknum) != NF_INET_LOCAL_IN)
  16
  17 #include <linux/list.h>
  18 #include <linux/netfilter/nf_conntrack_pptp.h>
  19 #include <net/netfilter/nf_conntrack_extend.h>
  20
  21 /* per conntrack: nat application helper private data */
  22 union nf_conntrack_nat_help {
  23         /* insert nat helper private data here */
  24 #if defined(CONFIG_NF_NAT_PPTP) || defined(CONFIG_NF_NAT_PPTP_MODULE)
  25         struct nf_nat_pptp nat_pptp_info;
  26 #endif
  27 };
  28
  29 struct nf_conn;
  30
  31 /* The structure embedded in the conntrack structure. */
  32 struct nf_conn_nat {
  33         union nf_conntrack_nat_help help;
  34 #if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
  35         int masq_index;
  36 #endif
  37 };
  38
  39 /* Set up the info structure to map into this range. */
  40 unsigned int nf_nat_setup_info(struct nf_conn *ct,
  41                                const struct nf_nat_range2 *range,
  42                                enum nf_nat_manip_type maniptype);
  43
  44 extern unsigned int nf_nat_alloc_null_binding(struct nf_conn *ct,
  45                                               unsigned int hooknum);
  46
  47 struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct);
  48
  49 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
  50 {
  51 #if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
  52         return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
  53 #else
  54         return NULL;
  55 #endif
  56 }
  57
  58 static inline bool nf_nat_oif_changed(unsigned int hooknum,
  59                                       enum ip_conntrack_info ctinfo,
  60                                       struct nf_conn_nat *nat,
  61                                       const struct net_device *out)
  62 {
  63 #if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
  64         return nat && nat->masq_index && hooknum == NF_INET_POST_ROUTING &&
  65                CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL &&
  66                nat->masq_index != out->ifindex;
  67 #else
  68         return false;
  69 #endif
  70 }
  71
  72 int nf_nat_register_fn(struct net *net, const struct nf_hook_ops *ops,
  73                        const struct nf_hook_ops *nat_ops, unsigned int ops_count);
  74 void nf_nat_unregister_fn(struct net *net, const struct nf_hook_ops *ops,
  75                           unsigned int ops_count);
  76 #endif