include/net/netfilter/nf_nat.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NF_NAT_H
   3 #define _NF_NAT_H
   4
   5 #include <linux/list.h>
   6 #include <linux/netfilter_ipv4.h>
   7 #include <linux/netfilter/nf_conntrack_pptp.h>
   8 #include <net/netfilter/nf_conntrack.h>
   9 #include <net/netfilter/nf_conntrack_extend.h>
  10 #include <net/netfilter/nf_conntrack_tuple.h>
  11 #include <uapi/linux/netfilter/nf_nat.h>
  12
  13 enum nf_nat_manip_type {
  14         NF_NAT_MANIP_SRC,
  15         NF_NAT_MANIP_DST
  16 };
  17
  18 /* SRC manip occurs POST_ROUTING or LOCAL_IN */
  19 #define HOOK2MANIP(hooknum) ((hooknum) != NF_INET_POST_ROUTING && \
  20                              (hooknum) != NF_INET_LOCAL_IN)
  21
  22 /* per conntrack: nat application helper private data */
  23 union nf_conntrack_nat_help {
  24         /* insert nat helper private data here */
  25 #if IS_ENABLED(CONFIG_NF_NAT_PPTP)
  26         struct nf_nat_pptp nat_pptp_info;
  27 #endif
  28 };
  29
  30 /* The structure embedded in the conntrack structure. */
  31 struct nf_conn_nat {
  32         union nf_conntrack_nat_help help;
  33 #if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
  34         int masq_index;
  35 #endif
  36 };
  37
  38 /* Set up the info structure to map into this range. */
  39 unsigned int nf_nat_setup_info(struct nf_conn *ct,
  40                                const struct nf_nat_range2 *range,
  41                                enum nf_nat_manip_type maniptype);
  42
  43 extern unsigned int nf_nat_alloc_null_binding(struct nf_conn *ct,
  44                                               unsigned int hooknum);
  45
  46 struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct);
  47
  48 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
  49 {
  50 #if IS_ENABLED(CONFIG_NF_NAT)
  51         return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
  52 #else
  53         return NULL;
  54 #endif
  55 }
  56
  57 static inline bool nf_nat_oif_changed(unsigned int hooknum,
  58                                       enum ip_conntrack_info ctinfo,
  59                                       struct nf_conn_nat *nat,
  60                                       const struct net_device *out)
  61 {
  62 #if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
  63         return nat && nat->masq_index && hooknum == NF_INET_POST_ROUTING &&
  64                CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL &&
  65                nat->masq_index != out->ifindex;
  66 #else
  67         return false;
  68 #endif
  69 }
  70
  71 int nf_nat_register_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
  72                        const struct nf_hook_ops *nat_ops, unsigned int ops_count);
  73 void nf_nat_unregister_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
  74                           unsigned int ops_count);
  75
  76 unsigned int nf_nat_packet(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
  77                            unsigned int hooknum, struct sk_buff *skb);
  78
  79 unsigned int nf_nat_manip_pkt(struct sk_buff *skb, struct nf_conn *ct,
  80                               enum nf_nat_manip_type mtype,
  81                               enum ip_conntrack_dir dir);
  82 void nf_nat_csum_recalc(struct sk_buff *skb,
  83                         u8 nfproto, u8 proto, void *data, __sum16 *check,
  84                         int datalen, int oldlen);
  85
  86 int nf_nat_icmp_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
  87                                   enum ip_conntrack_info ctinfo,
  88                                   unsigned int hooknum);
  89
  90 int nf_nat_icmpv6_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
  91                                     enum ip_conntrack_info ctinfo,
  92                                     unsigned int hooknum, unsigned int hdrlen);
  93
  94 int nf_nat_ipv4_register_fn(struct net *net, const struct nf_hook_ops *ops);
  95 void nf_nat_ipv4_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
  96
  97 int nf_nat_ipv6_register_fn(struct net *net, const struct nf_hook_ops *ops);
  98 void nf_nat_ipv6_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
  99
 100 int nf_nat_inet_register_fn(struct net *net, const struct nf_hook_ops *ops);
 101 void nf_nat_inet_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
 102
 103 unsigned int
 104 nf_nat_inet_fn(void *priv, struct sk_buff *skb,
 105                const struct nf_hook_state *state);
 106
 107 int nf_xfrm_me_harder(struct net *n, struct sk_buff *s, unsigned int family);
 108
 109 static inline int nf_nat_initialized(struct nf_conn *ct,
 110                                      enum nf_nat_manip_type manip)
 111 {
 112         if (manip == NF_NAT_MANIP_SRC)
 113                 return ct->status & IPS_SRC_NAT_DONE;
 114         else
 115                 return ct->status & IPS_DST_NAT_DONE;
 116 }
 117 #endif