include/net/netfilter/nf_conntrack_ecache.h

   1 /*
   2  * connection tracking event cache.
   3  */
   4
   5 #ifndef _NF_CONNTRACK_ECACHE_H
   6 #define _NF_CONNTRACK_ECACHE_H
   7 #include <net/netfilter/nf_conntrack.h>
   8
   9 #include <net/net_namespace.h>
  10 #include <net/netfilter/nf_conntrack_expect.h>
  11 #include <linux/netfilter/nf_conntrack_common.h>
  12 #include <linux/netfilter/nf_conntrack_tuple_common.h>
  13 #include <net/netfilter/nf_conntrack_extend.h>
  14
  15 struct nf_conntrack_ecache {
  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 pid;                /* netlink pid of destroyer */
  21 };
  22
  23 static inline struct nf_conntrack_ecache *
  24 nf_ct_ecache_find(const struct nf_conn *ct)
  25 {
  26 #ifdef CONFIG_NF_CONNTRACK_EVENTS
  27         return nf_ct_ext_find(ct, NF_CT_EXT_ECACHE);
  28 #else
  29         return NULL;
  30 #endif
  31 }
  32
  33 static inline struct nf_conntrack_ecache *
  34 nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
  35 {
  36 #ifdef CONFIG_NF_CONNTRACK_EVENTS
  37         struct net *net = nf_ct_net(ct);
  38         struct nf_conntrack_ecache *e;
  39
  40         if (!ctmask && !expmask && net->ct.sysctl_events) {
  41                 ctmask = ~0;
  42                 expmask = ~0;
  43         }
  44         if (!ctmask && !expmask)
  45                 return NULL;
  46
  47         e = nf_ct_ext_add(ct, NF_CT_EXT_ECACHE, gfp);
  48         if (e) {
  49                 e->ctmask  = ctmask;
  50                 e->expmask = expmask;
  51         }
  52         return e;
  53 #else
  54         return NULL;
  55 #endif
  56 };
  57
  58 #ifdef CONFIG_NF_CONNTRACK_EVENTS
  59 /* This structure is passed to event handler */
  60 struct nf_ct_event {
  61         struct nf_conn *ct;
  62         u32 pid;
  63         int report;
  64 };
  65
  66 struct nf_ct_event_notifier {
  67         int (*fcn)(unsigned int events, struct nf_ct_event *item);
  68 };
  69
  70 extern struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb;
  71 extern int nf_conntrack_register_notifier(struct nf_ct_event_notifier *nb);
  72 extern void nf_conntrack_unregister_notifier(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 nf_conntrack_ecache *e;
  80
  81         if (nf_conntrack_event_cb == NULL)
  82                 return;
  83
  84         e = nf_ct_ecache_find(ct);
  85         if (e == NULL)
  86                 return;
  87
  88         if (!(e->ctmask & (1 << event)))
  89                 return;
  90
  91         set_bit(event, &e->cache);
  92 }
  93
  94 static inline int
  95 nf_conntrack_eventmask_report(unsigned int eventmask,
  96                               struct nf_conn *ct,
  97                               u32 pid,
  98                               int report)
  99 {
 100         int ret = 0;
 101         struct nf_ct_event_notifier *notify;
 102         struct nf_conntrack_ecache *e;
 103
 104         rcu_read_lock();
 105         notify = rcu_dereference(nf_conntrack_event_cb);
 106         if (notify == NULL)
 107                 goto out_unlock;
 108
 109         e = nf_ct_ecache_find(ct);
 110         if (e == NULL)
 111                 goto out_unlock;
 112
 113         if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
 114                 struct nf_ct_event item = {
 115                         .ct     = ct,
 116                         .pid    = e->pid ? e->pid : pid,
 117                         .report = report
 118                 };
 119                 /* This is a resent of a destroy event? If so, skip missed */
 120                 unsigned long missed = e->pid ? 0 : e->missed;
 121
 122                 if (!((eventmask | missed) & e->ctmask))
 123                         goto out_unlock;
 124
 125                 ret = notify->fcn(eventmask | missed, &item);
 126                 if (unlikely(ret < 0 || missed)) {
 127                         spin_lock_bh(&ct->lock);
 128                         if (ret < 0) {
 129                                 /* This is a destroy event that has been
 130                                  * triggered by a process, we store the PID
 131                                  * to include it in the retransmission. */
 132                                 if (eventmask & (1 << IPCT_DESTROY) &&
 133                                     e->pid == 0 && pid != 0)
 134                                         e->pid = pid;
 135                                 else
 136                                         e->missed |= eventmask;
 137                         } else
 138                                 e->missed &= ~missed;
 139                         spin_unlock_bh(&ct->lock);
 140                 }
 141         }
 142 out_unlock:
 143         rcu_read_unlock();
 144         return ret;
 145 }
 146
 147 static inline int
 148 nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
 149                           u32 pid, int report)
 150 {
 151         return nf_conntrack_eventmask_report(1 << event, ct, pid, report);
 152 }
 153
 154 static inline int
 155 nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
 156 {
 157         return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
 158 }
 159
 160 struct nf_exp_event {
 161         struct nf_conntrack_expect *exp;
 162         u32 pid;
 163         int report;
 164 };
 165
 166 struct nf_exp_event_notifier {
 167         int (*fcn)(unsigned int events, struct nf_exp_event *item);
 168 };
 169
 170 extern struct nf_exp_event_notifier __rcu *nf_expect_event_cb;
 171 extern int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *nb);
 172 extern void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *nb);
 173
 174 static inline void
 175 nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
 176                           struct nf_conntrack_expect *exp,
 177                           u32 pid,
 178                           int report)
 179 {
 180         struct nf_exp_event_notifier *notify;
 181         struct nf_conntrack_ecache *e;
 182
 183         rcu_read_lock();
 184         notify = rcu_dereference(nf_expect_event_cb);
 185         if (notify == NULL)
 186                 goto out_unlock;
 187
 188         e = nf_ct_ecache_find(exp->master);
 189         if (e == NULL)
 190                 goto out_unlock;
 191
 192         if (e->expmask & (1 << event)) {
 193                 struct nf_exp_event item = {
 194                         .exp    = exp,
 195                         .pid    = pid,
 196                         .report = report
 197                 };
 198                 notify->fcn(1 << event, &item);
 199         }
 200 out_unlock:
 201         rcu_read_unlock();
 202 }
 203
 204 static inline void
 205 nf_ct_expect_event(enum ip_conntrack_expect_events event,
 206                    struct nf_conntrack_expect *exp)
 207 {
 208         nf_ct_expect_event_report(event, exp, 0, 0);
 209 }
 210
 211 extern int nf_conntrack_ecache_init(struct net *net);
 212 extern void nf_conntrack_ecache_fini(struct net *net);
 213
 214 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 215
 216 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
 217                                             struct nf_conn *ct) {}
 218 static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
 219                                                 struct nf_conn *ct,
 220                                                 u32 pid,
 221                                                 int report) { return 0; }
 222 static inline int nf_conntrack_event(enum ip_conntrack_events event,
 223                                      struct nf_conn *ct) { return 0; }
 224 static inline int nf_conntrack_event_report(enum ip_conntrack_events event,
 225                                             struct nf_conn *ct,
 226                                             u32 pid,
 227                                             int report) { return 0; }
 228 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
 229 static inline void nf_ct_expect_event(enum ip_conntrack_expect_events event,
 230                                       struct nf_conntrack_expect *exp) {}
 231 static inline void nf_ct_expect_event_report(enum ip_conntrack_expect_events e,
 232                                              struct nf_conntrack_expect *exp,
 233                                              u32 pid,
 234                                              int report) {}
 235
 236 static inline int nf_conntrack_ecache_init(struct net *net)
 237 {
 238         return 0;
 239 }
 240
 241 static inline void nf_conntrack_ecache_fini(struct net *net)
 242 {
 243 }
 244 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
 245
 246 #endif /*_NF_CONNTRACK_ECACHE_H*/
 247