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nf_conntrack_ecache.h
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1 /*
2  * connection tracking event cache.
3  */
4 
5 #ifndef _NF_CONNTRACK_ECACHE_H
6 #define _NF_CONNTRACK_ECACHE_H
8 
9 #include <net/net_namespace.h>
11 #include <linux/netfilter/nf_conntrack_common.h>
14 
16  unsigned long cache; /* bitops want long */
17  unsigned long missed; /* missed events */
18  u16 ctmask; /* bitmask of ct events to be delivered */
19  u16 expmask; /* bitmask of expect events to be delivered */
20  u32 portid; /* netlink portid of destroyer */
22 };
23 
24 static inline struct nf_conntrack_ecache *
25 nf_ct_ecache_find(const struct nf_conn *ct)
26 {
27 #ifdef CONFIG_NF_CONNTRACK_EVENTS
28  return nf_ct_ext_find(ct, NF_CT_EXT_ECACHE);
29 #else
30  return NULL;
31 #endif
32 }
33 
34 static inline struct nf_conntrack_ecache *
35 nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
36 {
37 #ifdef CONFIG_NF_CONNTRACK_EVENTS
38  struct net *net = nf_ct_net(ct);
39  struct nf_conntrack_ecache *e;
40 
41  if (!ctmask && !expmask && net->ct.sysctl_events) {
42  ctmask = ~0;
43  expmask = ~0;
44  }
45  if (!ctmask && !expmask)
46  return NULL;
47 
48  e = nf_ct_ext_add(ct, NF_CT_EXT_ECACHE, gfp);
49  if (e) {
50  e->ctmask = ctmask;
51  e->expmask = expmask;
52  }
53  return e;
54 #else
55  return NULL;
56 #endif
57 };
58 
59 #ifdef CONFIG_NF_CONNTRACK_EVENTS
60 /* This structure is passed to event handler */
61 struct nf_ct_event {
62  struct nf_conn *ct;
63  u32 portid;
64  int report;
65 };
66 
67 struct nf_ct_event_notifier {
68  int (*fcn)(unsigned int events, struct nf_ct_event *item);
69 };
70 
71 extern int nf_conntrack_register_notifier(struct net *net, struct nf_ct_event_notifier *nb);
72 extern void nf_conntrack_unregister_notifier(struct net *net, struct nf_ct_event_notifier *nb);
73 
74 extern void nf_ct_deliver_cached_events(struct nf_conn *ct);
75 
76 static inline void
77 nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
78 {
79  struct net *net = nf_ct_net(ct);
80  struct nf_conntrack_ecache *e;
81 
82  if (!rcu_access_pointer(net->ct.nf_conntrack_event_cb))
83  return;
84 
85  e = nf_ct_ecache_find(ct);
86  if (e == NULL)
87  return;
88 
89  set_bit(event, &e->cache);
90 }
91 
92 static inline int
93 nf_conntrack_eventmask_report(unsigned int eventmask,
94  struct nf_conn *ct,
95  u32 portid,
96  int report)
97 {
98  int ret = 0;
99  struct net *net = nf_ct_net(ct);
100  struct nf_ct_event_notifier *notify;
101  struct nf_conntrack_ecache *e;
102 
103  rcu_read_lock();
104  notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
105  if (notify == NULL)
106  goto out_unlock;
107 
108  e = nf_ct_ecache_find(ct);
109  if (e == NULL)
110  goto out_unlock;
111 
112  if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
113  struct nf_ct_event item = {
114  .ct = ct,
115  .portid = e->portid ? e->portid : portid,
116  .report = report
117  };
118  /* This is a resent of a destroy event? If so, skip missed */
119  unsigned long missed = e->portid ? 0 : e->missed;
120 
121  if (!((eventmask | missed) & e->ctmask))
122  goto out_unlock;
123 
124  ret = notify->fcn(eventmask | missed, &item);
125  if (unlikely(ret < 0 || missed)) {
126  spin_lock_bh(&ct->lock);
127  if (ret < 0) {
128  /* This is a destroy event that has been
129  * triggered by a process, we store the PORTID
130  * to include it in the retransmission. */
131  if (eventmask & (1 << IPCT_DESTROY) &&
132  e->portid == 0 && portid != 0)
133  e->portid = portid;
134  else
135  e->missed |= eventmask;
136  } else
137  e->missed &= ~missed;
138  spin_unlock_bh(&ct->lock);
139  }
140  }
141 out_unlock:
142  rcu_read_unlock();
143  return ret;
144 }
145 
146 static inline int
147 nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
148  u32 portid, int report)
149 {
150  return nf_conntrack_eventmask_report(1 << event, ct, portid, report);
151 }
152 
153 static inline int
154 nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
155 {
156  return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
157 }
158 
159 struct nf_exp_event {
160  struct nf_conntrack_expect *exp;
161  u32 portid;
162  int report;
163 };
164 
165 struct nf_exp_event_notifier {
166  int (*fcn)(unsigned int events, struct nf_exp_event *item);
167 };
168 
169 extern int nf_ct_expect_register_notifier(struct net *net, struct nf_exp_event_notifier *nb);
170 extern void nf_ct_expect_unregister_notifier(struct net *net, struct nf_exp_event_notifier *nb);
171 
172 static inline void
173 nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
174  struct nf_conntrack_expect *exp,
175  u32 portid,
176  int report)
177 {
178  struct net *net = nf_ct_exp_net(exp);
179  struct nf_exp_event_notifier *notify;
180  struct nf_conntrack_ecache *e;
181 
182  rcu_read_lock();
183  notify = rcu_dereference(net->ct.nf_expect_event_cb);
184  if (notify == NULL)
185  goto out_unlock;
186 
187  e = nf_ct_ecache_find(exp->master);
188  if (e == NULL)
189  goto out_unlock;
190 
191  if (e->expmask & (1 << event)) {
192  struct nf_exp_event item = {
193  .exp = exp,
194  .portid = portid,
195  .report = report
196  };
197  notify->fcn(1 << event, &item);
198  }
199 out_unlock:
200  rcu_read_unlock();
201 }
202 
203 static inline void
204 nf_ct_expect_event(enum ip_conntrack_expect_events event,
205  struct nf_conntrack_expect *exp)
206 {
207  nf_ct_expect_event_report(event, exp, 0, 0);
208 }
209 
210 extern int nf_conntrack_ecache_init(struct net *net);
211 extern void nf_conntrack_ecache_fini(struct net *net);
212 
213 #else /* CONFIG_NF_CONNTRACK_EVENTS */
214 
215 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
216  struct nf_conn *ct) {}
217 static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
218  struct nf_conn *ct,
219  u32 portid,
220  int report) { return 0; }
221 static inline int nf_conntrack_event(enum ip_conntrack_events event,
222  struct nf_conn *ct) { return 0; }
223 static inline int nf_conntrack_event_report(enum ip_conntrack_events event,
224  struct nf_conn *ct,
225  u32 portid,
226  int report) { return 0; }
227 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
228 static inline void nf_ct_expect_event(enum ip_conntrack_expect_events event,
229  struct nf_conntrack_expect *exp) {}
230 static inline void nf_ct_expect_event_report(enum ip_conntrack_expect_events e,
231  struct nf_conntrack_expect *exp,
232  u32 portid,
233  int report) {}
234 
235 static inline int nf_conntrack_ecache_init(struct net *net)
236 {
237  return 0;
238 }
239 
240 static inline void nf_conntrack_ecache_fini(struct net *net)
241 {
242 }
243 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
244 
245 #endif /*_NF_CONNTRACK_ECACHE_H*/
246