/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_NETFILTER_H
#define __LINUX_NETFILTER_H

#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/if.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/static_key.h>
#include <linux/netfilter_defs.h>
#include <linux/netdevice.h>
#include <net/net_namespace.h>

#ifdef CONFIG_NETFILTER
static inline int NF_DROP_GETERR(int verdict)
{
        return -(verdict >> NF_VERDICT_QBITS);
}

static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
                                   const union nf_inet_addr *a2)
{
        return a1->all[0] == a2->all[0] &&
               a1->all[1] == a2->all[1] &&
               a1->all[2] == a2->all[2] &&
               a1->all[3] == a2->all[3];
}

static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
                                     union nf_inet_addr *result,
                                     const union nf_inet_addr *mask)
{
        result->all[0] = a1->all[0] & mask->all[0];
        result->all[1] = a1->all[1] & mask->all[1];
        result->all[2] = a1->all[2] & mask->all[2];
        result->all[3] = a1->all[3] & mask->all[3];
}

int netfilter_init(void);

struct sk_buff;

struct nf_hook_ops;

struct sock;

struct nf_hook_state {
        unsigned int hook;
        u_int8_t pf;
        struct net_device *in;
        struct net_device *out;
        struct sock *sk;
        struct net *net;
        int (*okfn)(struct net *, struct sock *, struct sk_buff *);
};

typedef unsigned int nf_hookfn(void *priv,
                               struct sk_buff *skb,
                               const struct nf_hook_state *state);
struct nf_hook_ops {
        /* User fills in from here down. */
        nf_hookfn               *hook;
        struct net_device       *dev;
        void                    *priv;
        u_int8_t                pf;
        unsigned int            hooknum;
        /* Hooks are ordered in ascending priority. */
        int                     priority;
};

struct nf_hook_entry {
        nf_hookfn                       *hook;
        void                            *priv;
};

struct nf_hook_entries_rcu_head {
        struct rcu_head head;
        void    *allocation;
};

struct nf_hook_entries {
        u16                             num_hook_entries;
        /* padding */
        struct nf_hook_entry            hooks[];

        /* trailer: pointers to original orig_ops of each hook,
         * followed by rcu_head and scratch space used for freeing
         * the structure via call_rcu.
         *
         *   This is not part of struct nf_hook_entry since its only
         *   needed in slow path (hook register/unregister):
         * const struct nf_hook_ops     *orig_ops[]
         *
         *   For the same reason, we store this at end -- its
         *   only needed when a hook is deleted, not during
         *   packet path processing:
         * struct nf_hook_entries_rcu_head     head
         */
};

static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
{
        unsigned int n = e->num_hook_entries;
        const void *hook_end;

        hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */

        return (struct nf_hook_ops **)hook_end;
}

static inline int
nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
                     struct nf_hook_state *state)
{
        return entry->hook(entry->priv, skb, state);
}

static inline void nf_hook_state_init(struct nf_hook_state *p,
                                      unsigned int hook,
                                      u_int8_t pf,
                                      struct net_device *indev,
                                      struct net_device *outdev,
                                      struct sock *sk,
                                      struct net *net,
                                      int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
        p->hook = hook;
        p->pf = pf;
        p->in = indev;
        p->out = outdev;
        p->sk = sk;
        p->net = net;
        p->okfn = okfn;
}



struct nf_sockopt_ops {
        struct list_head list;

        u_int8_t pf;

        /* Non-inclusive ranges: use 0/0/NULL to never get called. */
        int set_optmin;
        int set_optmax;
        int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
#ifdef CONFIG_COMPAT
        int (*compat_set)(struct sock *sk, int optval,
                        void __user *user, unsigned int len);
#endif
        int get_optmin;
        int get_optmax;
        int (*get)(struct sock *sk, int optval, void __user *user, int *len);
#ifdef CONFIG_COMPAT
        int (*compat_get)(struct sock *sk, int optval,
                        void __user *user, int *len);
#endif
        /* Use the module struct to lock set/get code in place */
        struct module *owner;
};

/* Function to register/unregister hook points. */
int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
                          unsigned int n);
void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
                             unsigned int n);

/* Functions to register get/setsockopt ranges (non-inclusive).  You
   need to check permissions yourself! */
int nf_register_sockopt(struct nf_sockopt_ops *reg);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg);

#ifdef HAVE_JUMP_LABEL
extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
#endif

int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
                 const struct nf_hook_entries *e, unsigned int i);

/**
 *      nf_hook - call a netfilter hook
 *
 *      Returns 1 if the hook has allowed the packet to pass.  The function
 *      okfn must be invoked by the caller in this case.  Any other return
 *      value indicates the packet has been consumed by the hook.
 */
static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
                          struct sock *sk, struct sk_buff *skb,
                          struct net_device *indev, struct net_device *outdev,
                          int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
        struct nf_hook_entries *hook_head = NULL;
        int ret = 1;

#ifdef HAVE_JUMP_LABEL
        if (__builtin_constant_p(pf) &&
            __builtin_constant_p(hook) &&
            !static_key_false(&nf_hooks_needed[pf][hook]))
                return 1;
#endif

        rcu_read_lock();
        switch (pf) {
        case NFPROTO_IPV4:
                hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
                break;
        case NFPROTO_IPV6:
                hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
                break;
        case NFPROTO_ARP:
#ifdef CONFIG_NETFILTER_FAMILY_ARP
                if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp)))
                        break;
                hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
#endif
                break;
        case NFPROTO_BRIDGE:
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
                hook_head = rcu_dereference(net->nf.hooks_bridge[hook]);
#endif
                break;
#if IS_ENABLED(CONFIG_DECNET)
        case NFPROTO_DECNET:
                hook_head = rcu_dereference(net->nf.hooks_decnet[hook]);
                break;
#endif
        default:
                WARN_ON_ONCE(1);
                break;
        }

        if (hook_head) {
                struct nf_hook_state state;

                nf_hook_state_init(&state, hook, pf, indev, outdev,
                                   sk, net, okfn);

                ret = nf_hook_slow(skb, &state, hook_head, 0);
        }
        rcu_read_unlock();

        return ret;
}

/* Activate hook; either okfn or kfree_skb called, unless a hook
   returns NF_STOLEN (in which case, it's up to the hook to deal with
   the consequences).

   Returns -ERRNO if packet dropped.  Zero means queued, stolen or
   accepted.
*/

/* RR:
   > I don't want nf_hook to return anything because people might forget
   > about async and trust the return value to mean "packet was ok".

   AK:
   Just document it clearly, then you can expect some sense from kernel
   coders :)
*/

static inline int
NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
             struct sk_buff *skb, struct net_device *in, struct net_device *out,
             int (*okfn)(struct net *, struct sock *, struct sk_buff *),
             bool cond)
{
        int ret;

        if (!cond ||
            ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
                ret = okfn(net, sk, skb);
        return ret;
}

static inline int
NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
        struct net_device *in, struct net_device *out,
        int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
        int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
        if (ret == 1)
                ret = okfn(net, sk, skb);
        return ret;
}

/* Call setsockopt() */
int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
                  unsigned int len);
int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
                  int *len);
#ifdef CONFIG_COMPAT
int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
                char __user *opt, unsigned int len);
int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
                char __user *opt, int *len);
#endif

/* Call this before modifying an existing packet: ensures it is
   modifiable and linear to the point you care about (writable_len).
   Returns true or false. */
int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);

struct flowi;
struct nf_queue_entry;

__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
                    unsigned int dataoff, u_int8_t protocol,
                    unsigned short family);

__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
                            unsigned int dataoff, unsigned int len,
                            u_int8_t protocol, unsigned short family);
int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
             bool strict, unsigned short family);
int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry);

#include <net/flow.h>

struct nf_conn;
enum nf_nat_manip_type;
struct nlattr;
enum ip_conntrack_dir;

struct nf_nat_hook {
        int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip,
                               const struct nlattr *attr);
        void (*decode_session)(struct sk_buff *skb, struct flowi *fl);
        unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct,
                                  enum nf_nat_manip_type mtype,
                                  enum ip_conntrack_dir dir);
};

extern struct nf_nat_hook __rcu *nf_nat_hook;

static inline void
nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
{
#ifdef CONFIG_NF_NAT_NEEDED
        struct nf_nat_hook *nat_hook;

        rcu_read_lock();
        nat_hook = rcu_dereference(nf_nat_hook);
        if (nat_hook && nat_hook->decode_session)
                nat_hook->decode_session(skb, fl);
        rcu_read_unlock();
#endif
}

#else /* !CONFIG_NETFILTER */
static inline int
NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
             struct sk_buff *skb, struct net_device *in, struct net_device *out,
             int (*okfn)(struct net *, struct sock *, struct sk_buff *),
             bool cond)
{
        return okfn(net, sk, skb);
}

static inline int
NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
        struct sk_buff *skb, struct net_device *in, struct net_device *out,
        int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
        return okfn(net, sk, skb);
}

static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
                          struct sock *sk, struct sk_buff *skb,
                          struct net_device *indev, struct net_device *outdev,
                          int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
        return 1;
}
struct flowi;
static inline void
nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
{
}
#endif /*CONFIG_NETFILTER*/

#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
#include <linux/netfilter/nf_conntrack_zones_common.h>

extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
struct nf_conntrack_tuple;
bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
                         const struct sk_buff *skb);
#else
static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
struct nf_conntrack_tuple;
static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
                                       const struct sk_buff *skb)
{
        return false;
}
#endif

struct nf_conn;
enum ip_conntrack_info;

struct nf_ct_hook {
        int (*update)(struct net *net, struct sk_buff *skb);
        void (*destroy)(struct nf_conntrack *);
        bool (*get_tuple_skb)(struct nf_conntrack_tuple *,
                              const struct sk_buff *);
};
extern struct nf_ct_hook __rcu *nf_ct_hook;

struct nlattr;

struct nfnl_ct_hook {
        struct nf_conn *(*get_ct)(const struct sk_buff *skb,
                                  enum ip_conntrack_info *ctinfo);
        size_t (*build_size)(const struct nf_conn *ct);
        int (*build)(struct sk_buff *skb, struct nf_conn *ct,
                     enum ip_conntrack_info ctinfo,
                     u_int16_t ct_attr, u_int16_t ct_info_attr);
        int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
        int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
                             u32 portid, u32 report);
        void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
                           enum ip_conntrack_info ctinfo, s32 off);
};
extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;

/**
 * nf_skb_duplicated - TEE target has sent a packet
 *
 * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 *
 * This is used by xtables TEE target to prevent the duplicated skb from
 * being duplicated again.
 */
DECLARE_PER_CPU(bool, nf_skb_duplicated);

#endif /*__LINUX_NETFILTER_H*/