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