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 int nf_conntrack_register_notifier(struct net *net, struct nf_ct_event_notifier *nb);
  71 extern void nf_conntrack_unregister_notifier(struct net *net, struct nf_ct_event_notifier *nb);
  72
  73 extern void nf_ct_deliver_cached_events(struct nf_conn *ct);
  74
  75 static inline void
  76 nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
  77 {
  78         struct net *net = nf_ct_net(ct);
  79         struct nf_conntrack_ecache *e;
  80
  81         if (net->ct.nf_conntrack_event_cb == NULL)
  82                 return;
  83
  84         e = nf_ct_ecache_find(ct);
  85         if (e == NULL)
  86                 return;
  87
  88         set_bit(event, &e->cache);
  89 }
  90
  91 static inline int
  92 nf_conntrack_eventmask_report(unsigned int eventmask,
  93                               struct nf_conn *ct,
  94                               u32 pid,
  95                               int report)
  96 {
  97         int ret = 0;
  98         struct net *net = nf_ct_net(ct);
  99         struct nf_ct_event_notifier *notify;
 100         struct nf_conntrack_ecache *e;
 101
 102         rcu_read_lock();
 103         notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
 104         if (notify == NULL)
 105                 goto out_unlock;
 106
 107         e = nf_ct_ecache_find(ct);
 108         if (e == NULL)
 109                 goto out_unlock;
 110
 111         if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
 112                 struct nf_ct_event item = {
 113                         .ct     = ct,
 114                         .pid    = e->pid ? e->pid : pid,
 115                         .report = report
 116                 };
 117                 /* This is a resent of a destroy event? If so, skip missed */
 118                 unsigned long missed = e->pid ? 0 : e->missed;
 119
 120                 if (!((eventmask | missed) & e->ctmask))
 121                         goto out_unlock;
 122
 123                 ret = notify->fcn(eventmask | missed, &item);
 124                 if (unlikely(ret < 0 || missed)) {
 125                         spin_lock_bh(&ct->lock);
 126                         if (ret < 0) {
 127                                 /* This is a destroy event that has been
 128                                  * triggered by a process, we store the PID
 129                                  * to include it in the retransmission. */
 130                                 if (eventmask & (1 << IPCT_DESTROY) &&
 131                                     e->pid == 0 && pid != 0)
 132                                         e->pid = pid;
 133                                 else
 134                                         e->missed |= eventmask;
 135                         } else
 136                                 e->missed &= ~missed;
 137                         spin_unlock_bh(&ct->lock);
 138                 }
 139         }
 140 out_unlock:
 141         rcu_read_unlock();
 142         return ret;
 143 }
 144
 145 static inline int
 146 nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
 147                           u32 pid, int report)
 148 {
 149         return nf_conntrack_eventmask_report(1 << event, ct, pid, report);
 150 }
 151
 152 static inline int
 153 nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
 154 {
 155         return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
 156 }
 157
 158 struct nf_exp_event {
 159         struct nf_conntrack_expect *exp;
 160         u32 pid;
 161         int report;
 162 };
 163
 164 struct nf_exp_event_notifier {
 165         int (*fcn)(unsigned int events, struct nf_exp_event *item);
 166 };
 167
 168 extern int nf_ct_expect_register_notifier(struct net *net, struct nf_exp_event_notifier *nb);
 169 extern void nf_ct_expect_unregister_notifier(struct net *net, struct nf_exp_event_notifier *nb);
 170
 171 static inline void
 172 nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
 173                           struct nf_conntrack_expect *exp,
 174                           u32 pid,
 175                           int report)
 176 {
 177         struct net *net = nf_ct_exp_net(exp);
 178         struct nf_exp_event_notifier *notify;
 179         struct nf_conntrack_ecache *e;
 180
 181         rcu_read_lock();
 182         notify = rcu_dereference(net->ct.nf_expect_event_cb);
 183         if (notify == NULL)
 184                 goto out_unlock;
 185
 186         e = nf_ct_ecache_find(exp->master);
 187         if (e == NULL)
 188                 goto out_unlock;
 189
 190         if (e->expmask & (1 << event)) {
 191                 struct nf_exp_event item = {
 192                         .exp    = exp,
 193                         .pid    = pid,
 194                         .report = report
 195                 };
 196                 notify->fcn(1 << event, &item);
 197         }
 198 out_unlock:
 199         rcu_read_unlock();
 200 }
 201
 202 static inline void
 203 nf_ct_expect_event(enum ip_conntrack_expect_events event,
 204                    struct nf_conntrack_expect *exp)
 205 {
 206         nf_ct_expect_event_report(event, exp, 0, 0);
 207 }
 208
 209 extern int nf_conntrack_ecache_init(struct net *net);
 210 extern void nf_conntrack_ecache_fini(struct net *net);
 211
 212 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 213
 214 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
 215                                             struct nf_conn *ct) {}
 216 static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
 217                                                 struct nf_conn *ct,
 218                                                 u32 pid,
 219                                                 int report) { return 0; }
 220 static inline int nf_conntrack_event(enum ip_conntrack_events event,
 221                                      struct nf_conn *ct) { return 0; }
 222 static inline int nf_conntrack_event_report(enum ip_conntrack_events event,
 223                                             struct nf_conn *ct,
 224                                             u32 pid,
 225                                             int report) { return 0; }
 226 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
 227 static inline void nf_ct_expect_event(enum ip_conntrack_expect_events event,
 228                                       struct nf_conntrack_expect *exp) {}
 229 static inline void nf_ct_expect_event_report(enum ip_conntrack_expect_events e,
 230                                              struct nf_conntrack_expect *exp,
 231                                              u32 pid,
 232                                              int report) {}
 233
 234 static inline int nf_conntrack_ecache_init(struct net *net)
 235 {
 236         return 0;
 237 }
 238
 239 static inline void nf_conntrack_ecache_fini(struct net *net)
 240 {
 241 }
 242 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
 243
 244 #endif /*_NF_CONNTRACK_ECACHE_H*/
 245