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 portid;             /* netlink portid of destroyer */
  21         struct timer_list timeout;
  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