/*
 * connection tracking event cache.
 */

#ifndef _NF_CONNTRACK_ECACHE_H
#define _NF_CONNTRACK_ECACHE_H
#include <net/netfilter/nf_conntrack.h>

#include <net/net_namespace.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/netfilter/nf_conntrack_tuple_common.h>
#include <net/netfilter/nf_conntrack_extend.h>

struct nf_conntrack_ecache {
        unsigned long cache;    /* bitops want long */
        unsigned long missed;   /* missed events */
        u16 ctmask;             /* bitmask of ct events to be delivered */
        u16 expmask;            /* bitmask of expect events to be delivered */
        u32 portid;             /* netlink portid of destroyer */
};

static inline struct nf_conntrack_ecache *
nf_ct_ecache_find(const struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        return nf_ct_ext_find(ct, NF_CT_EXT_ECACHE);
#else
        return NULL;
#endif
}

static inline struct nf_conntrack_ecache *
nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        struct net *net = nf_ct_net(ct);
        struct nf_conntrack_ecache *e;

        if (!ctmask && !expmask && net->ct.sysctl_events) {
                ctmask = ~0;
                expmask = ~0;
        }
        if (!ctmask && !expmask)
                return NULL;

        e = nf_ct_ext_add(ct, NF_CT_EXT_ECACHE, gfp);
        if (e) {
                e->ctmask  = ctmask;
                e->expmask = expmask;
        }
        return e;
#else
        return NULL;
#endif
};

#ifdef CONFIG_NF_CONNTRACK_EVENTS
/* This structure is passed to event handler */
struct nf_ct_event {
        struct nf_conn *ct;
        u32 portid;
        int report;
};

struct nf_ct_event_notifier {
        int (*fcn)(unsigned int events, struct nf_ct_event *item);
};

int nf_conntrack_register_notifier(struct net *net,
                                   struct nf_ct_event_notifier *nb);
void nf_conntrack_unregister_notifier(struct net *net,
                                      struct nf_ct_event_notifier *nb);

void nf_ct_deliver_cached_events(struct nf_conn *ct);

static inline void
nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
{
        struct net *net = nf_ct_net(ct);
        struct nf_conntrack_ecache *e;

        if (!rcu_access_pointer(net->ct.nf_conntrack_event_cb))
                return;

        e = nf_ct_ecache_find(ct);
        if (e == NULL)
                return;

        set_bit(event, &e->cache);
}

static inline int
nf_conntrack_eventmask_report(unsigned int eventmask,
                              struct nf_conn *ct,
                              u32 portid,
                              int report)
{
        int ret = 0;
        struct net *net = nf_ct_net(ct);
        struct nf_ct_event_notifier *notify;
        struct nf_conntrack_ecache *e;

        rcu_read_lock();
        notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
        if (notify == NULL)
                goto out_unlock;

        e = nf_ct_ecache_find(ct);
        if (e == NULL)
                goto out_unlock;

        if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
                struct nf_ct_event item = {
                        .ct     = ct,
                        .portid = e->portid ? e->portid : portid,
                        .report = report
                };
                /* This is a resent of a destroy event? If so, skip missed */
                unsigned long missed = e->portid ? 0 : e->missed;

                if (!((eventmask | missed) & e->ctmask))
                        goto out_unlock;

                ret = notify->fcn(eventmask | missed, &item);
                if (unlikely(ret < 0 || missed)) {
                        spin_lock_bh(&ct->lock);
                        if (ret < 0) {
                                /* This is a destroy event that has been
                                 * triggered by a process, we store the PORTID
                                 * to include it in the retransmission. */
                                if (eventmask & (1 << IPCT_DESTROY) &&
                                    e->portid == 0 && portid != 0)
                                        e->portid = portid;
                                else
                                        e->missed |= eventmask;
                        } else
                                e->missed &= ~missed;
                        spin_unlock_bh(&ct->lock);
                }
        }
out_unlock:
        rcu_read_unlock();
        return ret;
}

static inline int
nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
                          u32 portid, int report)
{
        return nf_conntrack_eventmask_report(1 << event, ct, portid, report);
}

static inline int
nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
{
        return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
}

struct nf_exp_event {
        struct nf_conntrack_expect *exp;
        u32 portid;
        int report;
};

struct nf_exp_event_notifier {
        int (*fcn)(unsigned int events, struct nf_exp_event *item);
};

int nf_ct_expect_register_notifier(struct net *net,
                                   struct nf_exp_event_notifier *nb);
void nf_ct_expect_unregister_notifier(struct net *net,
                                      struct nf_exp_event_notifier *nb);

static inline void
nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
                          struct nf_conntrack_expect *exp,
                          u32 portid,
                          int report)
{
        struct net *net = nf_ct_exp_net(exp);
        struct nf_exp_event_notifier *notify;
        struct nf_conntrack_ecache *e;

        rcu_read_lock();
        notify = rcu_dereference(net->ct.nf_expect_event_cb);
        if (notify == NULL)
                goto out_unlock;

        e = nf_ct_ecache_find(exp->master);
        if (e == NULL)
                goto out_unlock;

        if (e->expmask & (1 << event)) {
                struct nf_exp_event item = {
                        .exp    = exp,
                        .portid = portid,
                        .report = report
                };
                notify->fcn(1 << event, &item);
        }
out_unlock:
        rcu_read_unlock();
}

static inline void
nf_ct_expect_event(enum ip_conntrack_expect_events event,
                   struct nf_conntrack_expect *exp)
{
        nf_ct_expect_event_report(event, exp, 0, 0);
}

int nf_conntrack_ecache_pernet_init(struct net *net);
void nf_conntrack_ecache_pernet_fini(struct net *net);

int nf_conntrack_ecache_init(void);
void nf_conntrack_ecache_fini(void);

static inline void nf_conntrack_ecache_delayed_work(struct net *net)
{
        if (!delayed_work_pending(&net->ct.ecache_dwork)) {
                schedule_delayed_work(&net->ct.ecache_dwork, HZ);
                net->ct.ecache_dwork_pending = true;
        }
}

static inline void nf_conntrack_ecache_work(struct net *net)
{
        if (net->ct.ecache_dwork_pending) {
                net->ct.ecache_dwork_pending = false;
                mod_delayed_work(system_wq, &net->ct.ecache_dwork, 0);
        }
}
#else /* CONFIG_NF_CONNTRACK_EVENTS */
static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
                                            struct nf_conn *ct) {}
static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
                                                struct nf_conn *ct,
                                                u32 portid,
                                                int report) { return 0; }
static inline int nf_conntrack_event(enum ip_conntrack_events event,
                                     struct nf_conn *ct) { return 0; }
static inline int nf_conntrack_event_report(enum ip_conntrack_events event,
                                            struct nf_conn *ct,
                                            u32 portid,
                                            int report) { return 0; }
static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
static inline void nf_ct_expect_event(enum ip_conntrack_expect_events event,
                                      struct nf_conntrack_expect *exp) {}
static inline void nf_ct_expect_event_report(enum ip_conntrack_expect_events e,
                                             struct nf_conntrack_expect *exp,
                                             u32 portid,
                                             int report) {}

static inline int nf_conntrack_ecache_pernet_init(struct net *net)
{
        return 0;
}

static inline void nf_conntrack_ecache_pernet_fini(struct net *net)
{
}

static inline int nf_conntrack_ecache_init(void)
{
        return 0;
}

static inline void nf_conntrack_ecache_fini(void)
{
}

static inline void nf_conntrack_ecache_delayed_work(struct net *net)
{
}

static inline void nf_conntrack_ecache_work(struct net *net)
{
}
#endif /* CONFIG_NF_CONNTRACK_EVENTS */

#endif /*_NF_CONNTRACK_ECACHE_H*/