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         set_bit(event, &e->cache);
  81 }
  82
  83 static inline int
  84 nf_conntrack_eventmask_report(unsigned int eventmask,
  85                               struct nf_conn *ct,
  86                               u32 pid,
  87                               int report)
  88 {
  89         int ret = 0;
  90         struct nf_ct_event_notifier *notify;
  91         struct nf_conntrack_ecache *e;
  92
  93         rcu_read_lock();
  94         notify = rcu_dereference(nf_conntrack_event_cb);
  95         if (notify == NULL)
  96                 goto out_unlock;
  97
  98         e = nf_ct_ecache_find(ct);
  99         if (e == NULL)
 100                 goto out_unlock;
 101
 102         if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
 103                 struct nf_ct_event item = {
 104                         .ct     = ct,
 105                         .pid    = e->pid ? e->pid : pid,
 106                         .report = report
 107                 };
 108                 /* This is a resent of a destroy event? If so, skip missed */
 109                 unsigned long missed = e->pid ? 0 : e->missed;
 110
 111                 if (!((eventmask | missed) & e->ctmask))
 112                         goto out_unlock;
 113
 114                 ret = notify->fcn(eventmask | missed, &item);
 115                 if (unlikely(ret < 0 || missed)) {
 116                         spin_lock_bh(&ct->lock);
 117                         if (ret < 0) {
 118                                 /* This is a destroy event that has been
 119                                  * triggered by a process, we store the PID
 120                                  * to include it in the retransmission. */
 121                                 if (eventmask & (1 << IPCT_DESTROY) &&
 122                                     e->pid == 0 && pid != 0)
 123                                         e->pid = pid;
 124                                 else
 125                                         e->missed |= eventmask;
 126                         } else
 127                                 e->missed &= ~missed;
 128                         spin_unlock_bh(&ct->lock);
 129                 }
 130         }
 131 out_unlock:
 132         rcu_read_unlock();
 133         return ret;
 134 }
 135
 136 static inline int
 137 nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
 138                           u32 pid, int report)
 139 {
 140         return nf_conntrack_eventmask_report(1 << event, ct, pid, report);
 141 }
 142
 143 static inline int
 144 nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
 145 {
 146         return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
 147 }
 148
 149 struct nf_exp_event {
 150         struct nf_conntrack_expect *exp;
 151         u32 pid;
 152         int report;
 153 };
 154
 155 struct nf_exp_event_notifier {
 156         int (*fcn)(unsigned int events, struct nf_exp_event *item);
 157 };
 158
 159 extern struct nf_exp_event_notifier *nf_expect_event_cb;
 160 extern int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *nb);
 161 extern void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *nb);
 162
 163 static inline void
 164 nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
 165                           struct nf_conntrack_expect *exp,
 166                           u32 pid,
 167                           int report)
 168 {
 169         struct nf_exp_event_notifier *notify;
 170         struct nf_conntrack_ecache *e;
 171
 172         rcu_read_lock();
 173         notify = rcu_dereference(nf_expect_event_cb);
 174         if (notify == NULL)
 175                 goto out_unlock;
 176
 177         e = nf_ct_ecache_find(exp->master);
 178         if (e == NULL)
 179                 goto out_unlock;
 180
 181         if (e->expmask & (1 << event)) {
 182                 struct nf_exp_event item = {
 183                         .exp    = exp,
 184                         .pid    = pid,
 185                         .report = report
 186                 };
 187                 notify->fcn(1 << event, &item);
 188         }
 189 out_unlock:
 190         rcu_read_unlock();
 191 }
 192
 193 static inline void
 194 nf_ct_expect_event(enum ip_conntrack_expect_events event,
 195                    struct nf_conntrack_expect *exp)
 196 {
 197         nf_ct_expect_event_report(event, exp, 0, 0);
 198 }
 199
 200 extern int nf_conntrack_ecache_init(struct net *net);
 201 extern void nf_conntrack_ecache_fini(struct net *net);
 202
 203 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 204
 205 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
 206                                             struct nf_conn *ct) {}
 207 static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
 208                                                 struct nf_conn *ct,
 209                                                 u32 pid,
 210                                                 int report) { return 0; }
 211 static inline int nf_conntrack_event(enum ip_conntrack_events event,
 212                                      struct nf_conn *ct) { return 0; }
 213 static inline int nf_conntrack_event_report(enum ip_conntrack_events event,
 214                                             struct nf_conn *ct,
 215                                             u32 pid,
 216                                             int report) { return 0; }
 217 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
 218 static inline void nf_ct_expect_event(enum ip_conntrack_expect_events event,
 219                                       struct nf_conntrack_expect *exp) {}
 220 static inline void nf_ct_expect_event_report(enum ip_conntrack_expect_events e,
 221                                              struct nf_conntrack_expect *exp,
 222                                              u32 pid,
 223                                              int report) {}
 224
 225 static inline int nf_conntrack_ecache_init(struct net *net)
 226 {
 227         return 0;
 228 }
 229
 230 static inline void nf_conntrack_ecache_fini(struct net *net)
 231 {
 232 }
 233 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
 234
 235 #endif /*_NF_CONNTRACK_ECACHE_H*/
 236