xref: /openbmc/linux/include/net/netfilter/nf_conntrack.h (revision c900529f3d9161bfde5cca0754f83b4d3c3e0220)
1  /* SPDX-License-Identifier: GPL-2.0 */
2  /*
3   * Connection state tracking for netfilter.  This is separated from,
4   * but required by, the (future) NAT layer; it can also be used by an iptables
5   * extension.
6   *
7   * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
8   *	- generalize L3 protocol dependent part.
9   *
10   * Derived from include/linux/netfiter_ipv4/ip_conntrack.h
11   */
12  
13  #ifndef _NF_CONNTRACK_H
14  #define _NF_CONNTRACK_H
15  
16  #include <linux/bitops.h>
17  #include <linux/compiler.h>
18  
19  #include <linux/netfilter/nf_conntrack_common.h>
20  #include <linux/netfilter/nf_conntrack_tcp.h>
21  #include <linux/netfilter/nf_conntrack_dccp.h>
22  #include <linux/netfilter/nf_conntrack_sctp.h>
23  #include <linux/netfilter/nf_conntrack_proto_gre.h>
24  
25  #include <net/netfilter/nf_conntrack_tuple.h>
26  
27  struct nf_ct_udp {
28  	unsigned long	stream_ts;
29  };
30  
31  /* per conntrack: protocol private data */
32  union nf_conntrack_proto {
33  	/* insert conntrack proto private data here */
34  	struct nf_ct_dccp dccp;
35  	struct ip_ct_sctp sctp;
36  	struct ip_ct_tcp tcp;
37  	struct nf_ct_udp udp;
38  	struct nf_ct_gre gre;
39  	unsigned int tmpl_padto;
40  };
41  
42  union nf_conntrack_expect_proto {
43  	/* insert expect proto private data here */
44  };
45  
46  struct nf_conntrack_net_ecache {
47  	struct delayed_work dwork;
48  	spinlock_t dying_lock;
49  	struct hlist_nulls_head dying_list;
50  };
51  
52  struct nf_conntrack_net {
53  	/* only used when new connection is allocated: */
54  	atomic_t count;
55  	unsigned int expect_count;
56  
57  	/* only used from work queues, configuration plane, and so on: */
58  	unsigned int users4;
59  	unsigned int users6;
60  	unsigned int users_bridge;
61  #ifdef CONFIG_SYSCTL
62  	struct ctl_table_header	*sysctl_header;
63  #endif
64  #ifdef CONFIG_NF_CONNTRACK_EVENTS
65  	struct nf_conntrack_net_ecache ecache;
66  #endif
67  };
68  
69  #include <linux/types.h>
70  #include <linux/skbuff.h>
71  
72  #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
73  #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
74  
75  struct nf_conn {
76  	/* Usage count in here is 1 for hash table, 1 per skb,
77  	 * plus 1 for any connection(s) we are `master' for
78  	 *
79  	 * Hint, SKB address this struct and refcnt via skb->_nfct and
80  	 * helpers nf_conntrack_get() and nf_conntrack_put().
81  	 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
82  	 * except that the latter uses internal indirection and does not
83  	 * result in a conntrack module dependency.
84  	 * beware nf_ct_get() is different and don't inc refcnt.
85  	 */
86  	struct nf_conntrack ct_general;
87  
88  	spinlock_t	lock;
89  	/* jiffies32 when this ct is considered dead */
90  	u32 timeout;
91  
92  #ifdef CONFIG_NF_CONNTRACK_ZONES
93  	struct nf_conntrack_zone zone;
94  #endif
95  	/* XXX should I move this to the tail ? - Y.K */
96  	/* These are my tuples; original and reply */
97  	struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
98  
99  	/* Have we seen traffic both ways yet? (bitset) */
100  	unsigned long status;
101  
102  	possible_net_t ct_net;
103  
104  #if IS_ENABLED(CONFIG_NF_NAT)
105  	struct hlist_node	nat_bysource;
106  #endif
107  	/* all members below initialized via memset */
108  	struct { } __nfct_init_offset;
109  
110  	/* If we were expected by an expectation, this will be it */
111  	struct nf_conn *master;
112  
113  #if defined(CONFIG_NF_CONNTRACK_MARK)
114  	u_int32_t mark;
115  #endif
116  
117  #ifdef CONFIG_NF_CONNTRACK_SECMARK
118  	u_int32_t secmark;
119  #endif
120  
121  	/* Extensions */
122  	struct nf_ct_ext *ext;
123  
124  	/* Storage reserved for other modules, must be the last member */
125  	union nf_conntrack_proto proto;
126  };
127  
128  static inline struct nf_conn *
nf_ct_to_nf_conn(const struct nf_conntrack * nfct)129  nf_ct_to_nf_conn(const struct nf_conntrack *nfct)
130  {
131  	return container_of(nfct, struct nf_conn, ct_general);
132  }
133  
134  static inline struct nf_conn *
nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash * hash)135  nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
136  {
137  	return container_of(hash, struct nf_conn,
138  			    tuplehash[hash->tuple.dst.dir]);
139  }
140  
nf_ct_l3num(const struct nf_conn * ct)141  static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
142  {
143  	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
144  }
145  
nf_ct_protonum(const struct nf_conn * ct)146  static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
147  {
148  	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
149  }
150  
151  #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
152  
153  /* get master conntrack via master expectation */
154  #define master_ct(conntr) (conntr->master)
155  
156  extern struct net init_net;
157  
nf_ct_net(const struct nf_conn * ct)158  static inline struct net *nf_ct_net(const struct nf_conn *ct)
159  {
160  	return read_pnet(&ct->ct_net);
161  }
162  
163  /* Alter reply tuple (maybe alter helper). */
164  void nf_conntrack_alter_reply(struct nf_conn *ct,
165  			      const struct nf_conntrack_tuple *newreply);
166  
167  /* Is this tuple taken? (ignoring any belonging to the given
168     conntrack). */
169  int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
170  			     const struct nf_conn *ignored_conntrack);
171  
172  /* Return conntrack_info and tuple hash for given skb. */
173  static inline struct nf_conn *
nf_ct_get(const struct sk_buff * skb,enum ip_conntrack_info * ctinfo)174  nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
175  {
176  	unsigned long nfct = skb_get_nfct(skb);
177  
178  	*ctinfo = nfct & NFCT_INFOMASK;
179  	return (struct nf_conn *)(nfct & NFCT_PTRMASK);
180  }
181  
182  void nf_ct_destroy(struct nf_conntrack *nfct);
183  
184  void nf_conntrack_tcp_set_closing(struct nf_conn *ct);
185  
186  /* decrement reference count on a conntrack */
nf_ct_put(struct nf_conn * ct)187  static inline void nf_ct_put(struct nf_conn *ct)
188  {
189  	if (ct && refcount_dec_and_test(&ct->ct_general.use))
190  		nf_ct_destroy(&ct->ct_general);
191  }
192  
193  /* load module; enable/disable conntrack in this namespace */
194  int nf_ct_netns_get(struct net *net, u8 nfproto);
195  void nf_ct_netns_put(struct net *net, u8 nfproto);
196  
197  /*
198   * Allocate a hashtable of hlist_head (if nulls == 0),
199   * or hlist_nulls_head (if nulls == 1)
200   */
201  void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
202  
203  int nf_conntrack_hash_check_insert(struct nf_conn *ct);
204  bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
205  
206  bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
207  		       u_int16_t l3num, struct net *net,
208  		       struct nf_conntrack_tuple *tuple);
209  
210  void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
211  			  const struct sk_buff *skb,
212  			  u32 extra_jiffies, bool do_acct);
213  
214  /* Refresh conntrack for this many jiffies and do accounting */
nf_ct_refresh_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,u32 extra_jiffies)215  static inline void nf_ct_refresh_acct(struct nf_conn *ct,
216  				      enum ip_conntrack_info ctinfo,
217  				      const struct sk_buff *skb,
218  				      u32 extra_jiffies)
219  {
220  	__nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true);
221  }
222  
223  /* Refresh conntrack for this many jiffies */
nf_ct_refresh(struct nf_conn * ct,const struct sk_buff * skb,u32 extra_jiffies)224  static inline void nf_ct_refresh(struct nf_conn *ct,
225  				 const struct sk_buff *skb,
226  				 u32 extra_jiffies)
227  {
228  	__nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false);
229  }
230  
231  /* kill conntrack and do accounting */
232  bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
233  		     const struct sk_buff *skb);
234  
235  /* kill conntrack without accounting */
nf_ct_kill(struct nf_conn * ct)236  static inline bool nf_ct_kill(struct nf_conn *ct)
237  {
238  	return nf_ct_delete(ct, 0, 0);
239  }
240  
241  struct nf_ct_iter_data {
242  	struct net *net;
243  	void *data;
244  	u32 portid;
245  	int report;
246  };
247  
248  /* Iterate over all conntracks: if iter returns true, it's deleted. */
249  void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
250  			       const struct nf_ct_iter_data *iter_data);
251  
252  /* also set unconfirmed conntracks as dying. Only use in module exit path. */
253  void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
254  			   void *data);
255  
256  struct nf_conntrack_zone;
257  
258  void nf_conntrack_free(struct nf_conn *ct);
259  struct nf_conn *nf_conntrack_alloc(struct net *net,
260  				   const struct nf_conntrack_zone *zone,
261  				   const struct nf_conntrack_tuple *orig,
262  				   const struct nf_conntrack_tuple *repl,
263  				   gfp_t gfp);
264  
nf_ct_is_template(const struct nf_conn * ct)265  static inline int nf_ct_is_template(const struct nf_conn *ct)
266  {
267  	return test_bit(IPS_TEMPLATE_BIT, &ct->status);
268  }
269  
270  /* It's confirmed if it is, or has been in the hash table. */
nf_ct_is_confirmed(const struct nf_conn * ct)271  static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
272  {
273  	return test_bit(IPS_CONFIRMED_BIT, &ct->status);
274  }
275  
nf_ct_is_dying(const struct nf_conn * ct)276  static inline int nf_ct_is_dying(const struct nf_conn *ct)
277  {
278  	return test_bit(IPS_DYING_BIT, &ct->status);
279  }
280  
281  /* Packet is received from loopback */
nf_is_loopback_packet(const struct sk_buff * skb)282  static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
283  {
284  	return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
285  }
286  
287  #define nfct_time_stamp ((u32)(jiffies))
288  
289  /* jiffies until ct expires, 0 if already expired */
nf_ct_expires(const struct nf_conn * ct)290  static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
291  {
292  	s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
293  
294  	return max(timeout, 0);
295  }
296  
nf_ct_is_expired(const struct nf_conn * ct)297  static inline bool nf_ct_is_expired(const struct nf_conn *ct)
298  {
299  	return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
300  }
301  
302  /* use after obtaining a reference count */
nf_ct_should_gc(const struct nf_conn * ct)303  static inline bool nf_ct_should_gc(const struct nf_conn *ct)
304  {
305  	return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
306  	       !nf_ct_is_dying(ct);
307  }
308  
309  #define	NF_CT_DAY	(86400 * HZ)
310  
311  /* Set an arbitrary timeout large enough not to ever expire, this save
312   * us a check for the IPS_OFFLOAD_BIT from the packet path via
313   * nf_ct_is_expired().
314   */
nf_ct_offload_timeout(struct nf_conn * ct)315  static inline void nf_ct_offload_timeout(struct nf_conn *ct)
316  {
317  	if (nf_ct_expires(ct) < NF_CT_DAY / 2)
318  		WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY);
319  }
320  
321  struct kernel_param;
322  
323  int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
324  int nf_conntrack_hash_resize(unsigned int hashsize);
325  
326  extern struct hlist_nulls_head *nf_conntrack_hash;
327  extern unsigned int nf_conntrack_htable_size;
328  extern seqcount_spinlock_t nf_conntrack_generation;
329  extern unsigned int nf_conntrack_max;
330  
331  /* must be called with rcu read lock held */
332  static inline void
nf_conntrack_get_ht(struct hlist_nulls_head ** hash,unsigned int * hsize)333  nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
334  {
335  	struct hlist_nulls_head *hptr;
336  	unsigned int sequence, hsz;
337  
338  	do {
339  		sequence = read_seqcount_begin(&nf_conntrack_generation);
340  		hsz = nf_conntrack_htable_size;
341  		hptr = nf_conntrack_hash;
342  	} while (read_seqcount_retry(&nf_conntrack_generation, sequence));
343  
344  	*hash = hptr;
345  	*hsize = hsz;
346  }
347  
348  struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
349  				 const struct nf_conntrack_zone *zone,
350  				 gfp_t flags);
351  void nf_ct_tmpl_free(struct nf_conn *tmpl);
352  
353  u32 nf_ct_get_id(const struct nf_conn *ct);
354  u32 nf_conntrack_count(const struct net *net);
355  
356  static inline void
nf_ct_set(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info info)357  nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
358  {
359  	skb_set_nfct(skb, (unsigned long)ct | info);
360  }
361  
362  extern unsigned int nf_conntrack_net_id;
363  
nf_ct_pernet(const struct net * net)364  static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
365  {
366  	return net_generic(net, nf_conntrack_net_id);
367  }
368  
369  int nf_ct_skb_network_trim(struct sk_buff *skb, int family);
370  int nf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
371  			   u16 zone, u8 family, u8 *proto, u16 *mru);
372  
373  #define NF_CT_STAT_INC(net, count)	  __this_cpu_inc((net)->ct.stat->count)
374  #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
375  #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
376  
377  #define MODULE_ALIAS_NFCT_HELPER(helper) \
378          MODULE_ALIAS("nfct-helper-" helper)
379  
380  #endif /* _NF_CONNTRACK_H */
381