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
 13enum 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 */
 23union 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. */
 31struct 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. */
 39unsigned int nf_nat_setup_info(struct nf_conn *ct,
 40			       const struct nf_nat_range2 *range,
 41			       enum nf_nat_manip_type maniptype);
 42
 43extern unsigned int nf_nat_alloc_null_binding(struct nf_conn *ct,
 44					      unsigned int hooknum);
 45
 46struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct);
 47
 48static 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
 57static 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
 71int 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);
 73void nf_nat_unregister_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
 74			  unsigned int ops_count);
 75
 76unsigned int nf_nat_packet(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 77			   unsigned int hooknum, struct sk_buff *skb);
 78
 79unsigned 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);
 82void nf_nat_csum_recalc(struct sk_buff *skb,
 83			u8 nfproto, u8 proto, void *data, __sum16 *check,
 84			int datalen, int oldlen);
 85
 86int nf_nat_icmp_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
 87				  enum ip_conntrack_info ctinfo,
 88				  unsigned int hooknum);
 89
 90int 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
 94int nf_nat_ipv4_register_fn(struct net *net, const struct nf_hook_ops *ops);
 95void nf_nat_ipv4_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
 96
 97int nf_nat_ipv6_register_fn(struct net *net, const struct nf_hook_ops *ops);
 98void nf_nat_ipv6_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
 99
100int nf_nat_inet_register_fn(struct net *net, const struct nf_hook_ops *ops);
101void nf_nat_inet_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
102
103unsigned int
104nf_nat_inet_fn(void *priv, struct sk_buff *skb,
105	       const struct nf_hook_state *state);
106
107int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct,
108	      enum ip_conntrack_info ctinfo, int *action,
109	      const struct nf_nat_range2 *range, bool commit);
110
111static inline int nf_nat_initialized(const struct nf_conn *ct,
112				     enum nf_nat_manip_type manip)
113{
114	if (manip == NF_NAT_MANIP_SRC)
115		return ct->status & IPS_SRC_NAT_DONE;
116	else
117		return ct->status & IPS_DST_NAT_DONE;
118}
119#endif