/* SPDX-License-Identifier: GPL-2.0 */
/*
 * 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>

enum nf_ct_ecache_state {
        NFCT_ECACHE_UNKNOWN,            /* destroy event not sent */
        NFCT_ECACHE_DESTROY_FAIL,       /* tried but failed to send destroy event */
        NFCT_ECACHE_DESTROY_SENT,       /* sent destroy event after failure */
};

struct nf_conntrack_ecache {
        unsigned long cache;            /* bitops want long */
        u16 missed;                     /* missed events */
        u16 ctmask;                     /* bitmask of ct events to be delivered */
        u16 expmask;                    /* bitmask of expect events to be delivered */
        enum nf_ct_ecache_state state:8;/* ecache state */
        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);
int nf_conntrack_eventmask_report(unsigned int eventmask, struct nf_conn *ct,
                                  u32 portid, int report);

#else

static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct)
{
}

static inline int nf_conntrack_eventmask_report(unsigned int eventmask,
                                                struct nf_conn *ct,
                                                u32 portid,
                                                int report)
{
        return 0;
}

#endif

static inline void
nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        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);
#endif
}

static inline int
nf_conntrack_event_report(enum ip_conntrack_events event, struct nf_conn *ct,
                          u32 portid, int report)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        const struct net *net = nf_ct_net(ct);

        if (!rcu_access_pointer(net->ct.nf_conntrack_event_cb))
                return 0;

        return nf_conntrack_eventmask_report(1 << event, ct, portid, report);
#else
        return 0;
#endif
}

static inline int
nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        const struct net *net = nf_ct_net(ct);

        if (!rcu_access_pointer(net->ct.nf_conntrack_event_cb))
                return 0;

        return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
#else
        return 0;
#endif
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS

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);

void nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
                               struct nf_conntrack_expect *exp,
                               u32 portid, int report);

void 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);

#else /* CONFIG_NF_CONNTRACK_EVENTS */

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 void nf_conntrack_ecache_pernet_init(struct net *net)
{
}

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)
{
}

#endif /* CONFIG_NF_CONNTRACK_EVENTS */

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

static inline void nf_conntrack_ecache_work(struct net *net)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        if (net->ct.ecache_dwork_pending) {
                net->ct.ecache_dwork_pending = false;
                mod_delayed_work(system_wq, &net->ct.ecache_dwork, 0);
        }
#endif
}

#endif /*_NF_CONNTRACK_ECACHE_H*/