/* 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>
#include <asm/local64.h>

enum nf_ct_ecache_state {
        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 */
#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
        local64_t timestamp;            /* event timestamp, in nanoseconds */
#endif
        u16 ctmask;                     /* bitmask of ct events to be delivered */
        u16 expmask;                    /* bitmask of expect events to be delivered */
        u32 missed;                     /* missed events */
        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 bool nf_ct_ecache_exist(const struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        return nf_ct_ext_exist(ct, NF_CT_EXT_ECACHE);
#else
        return false;
#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_exp_event {
        struct nf_conntrack_expect *exp;
        u32 portid;
        int report;
};

struct nf_ct_event_notifier {
        int (*ct_event)(unsigned int events, const struct nf_ct_event *item);
        int (*exp_event)(unsigned int events, const struct nf_exp_event *item);
};

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

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);

bool nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp);
#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;
}

static inline bool nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
{
        return false;
}
#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;

#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
        /* renew only if this is the first cached event, so that the
         * timestamp reflects the first, not the last, generated event.
         */
        if (local64_read(&e->timestamp) && READ_ONCE(e->cache) == 0)
                local64_set(&e->timestamp, ktime_get_real_ns());
#endif

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

static inline int
nf_conntrack_event(enum ip_conntrack_events event, struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
        if (nf_ct_ecache_exist(ct))
                return nf_conntrack_eventmask_report(1 << event, ct, 0, 0);
#endif
        return 0;
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS
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_work(struct net *net, enum nf_ct_ecache_state state);

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

struct nf_conntrack_net_ecache *nf_conn_pernet_ecache(const struct net *net);

static inline bool nf_conntrack_ecache_dwork_pending(const struct net *net)
{
        return net->ct.ecache_dwork_pending;
}
#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_work(struct net *net,
                                            enum nf_ct_ecache_state s)
{
}

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

static inline void nf_conntrack_ecache_pernet_fini(struct net *net)
{
}
static inline bool nf_conntrack_ecache_dwork_pending(const struct net *net) { return false; }
#endif /* CONFIG_NF_CONNTRACK_EVENTS */
#endif /*_NF_CONNTRACK_ECACHE_H*/