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

#include <linux/netlink.h>
#include <linux/capability.h>
#include <net/netlink.h>
#include <uapi/linux/netfilter/nfnetlink.h>

struct nfnl_info {
        struct net              *net;
        struct sock             *sk;
        const struct nlmsghdr   *nlh;
        const struct nfgenmsg   *nfmsg;
        struct netlink_ext_ack  *extack;
};

enum nfnl_callback_type {
        NFNL_CB_UNSPEC  = 0,
        NFNL_CB_MUTEX,
        NFNL_CB_RCU,
        NFNL_CB_BATCH,
};

struct nfnl_callback {
        int (*call)(struct sk_buff *skb, const struct nfnl_info *info,
                    const struct nlattr * const cda[]);
        const struct nla_policy *policy;
        enum nfnl_callback_type type;
        __u16                   attr_count;
};

enum nfnl_abort_action {
        NFNL_ABORT_NONE         = 0,
        NFNL_ABORT_AUTOLOAD,
        NFNL_ABORT_VALIDATE,
};

struct nfnetlink_subsystem {
        const char *name;
        __u8 subsys_id;                 /* nfnetlink subsystem ID */
        __u8 cb_count;                  /* number of callbacks */
        const struct nfnl_callback *cb; /* callback for individual types */
        struct module *owner;
        int (*commit)(struct net *net, struct sk_buff *skb);
        int (*abort)(struct net *net, struct sk_buff *skb,
                     enum nfnl_abort_action action);
        bool (*valid_genid)(struct net *net, u32 genid);
};

int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n);
int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n);

int nfnetlink_has_listeners(struct net *net, unsigned int group);
int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
                   unsigned int group, int echo, gfp_t flags);
int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error);
int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid);
void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
                         __u32 group, gfp_t allocation);

static inline u16 nfnl_msg_type(u8 subsys, u8 msg_type)
{
        return subsys << 8 | msg_type;
}

static inline void nfnl_fill_hdr(struct nlmsghdr *nlh, u8 family, u8 version,
                                 __be16 res_id)
{
        struct nfgenmsg *nfmsg;

        nfmsg = nlmsg_data(nlh);
        nfmsg->nfgen_family = family;
        nfmsg->version = version;
        nfmsg->res_id = res_id;
}

static inline struct nlmsghdr *nfnl_msg_put(struct sk_buff *skb, u32 portid,
                                            u32 seq, int type, int flags,
                                            u8 family, u8 version,
                                            __be16 res_id)
{
        struct nlmsghdr *nlh;

        nlh = nlmsg_put(skb, portid, seq, type, sizeof(struct nfgenmsg), flags);
        if (!nlh)
                return NULL;

        nfnl_fill_hdr(nlh, family, version, res_id);

        return nlh;
}

void nfnl_lock(__u8 subsys_id);
void nfnl_unlock(__u8 subsys_id);
#ifdef CONFIG_PROVE_LOCKING
bool lockdep_nfnl_is_held(__u8 subsys_id);
#else
static inline bool lockdep_nfnl_is_held(__u8 subsys_id)
{
        return true;
}
#endif /* CONFIG_PROVE_LOCKING */

#define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
        MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))

#endif  /* _NFNETLINK_H */