/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Generic netlink handshake service
 *
 * Author: Chuck Lever <chuck.lever@oracle.com>
 *
 * Copyright (c) 2023, Oracle and/or its affiliates.
 */

#ifndef _INTERNAL_HANDSHAKE_H
#define _INTERNAL_HANDSHAKE_H

/* Per-net namespace context */
struct handshake_net {
        spinlock_t              hn_lock;        /* protects next 3 fields */
        int                     hn_pending;
        int                     hn_pending_max;
        struct list_head        hn_requests;

        unsigned long           hn_flags;
};

enum hn_flags_bits {
        HANDSHAKE_F_NET_DRAINING,
};

struct handshake_proto;

/* One handshake request */
struct handshake_req {
        struct list_head                hr_list;
        struct rhash_head               hr_rhash;
        unsigned long                   hr_flags;
        const struct handshake_proto    *hr_proto;
        struct sock                     *hr_sk;
        void                            (*hr_odestruct)(struct sock *sk);

        /* Always the last field */
        char                            hr_priv[];
};

enum hr_flags_bits {
        HANDSHAKE_F_REQ_COMPLETED,
        HANDSHAKE_F_REQ_SESSION,
};

struct genl_info;

/* Invariants for all handshake requests for one transport layer
 * security protocol
 */
struct handshake_proto {
        int                     hp_handler_class;
        size_t                  hp_privsize;
        unsigned long           hp_flags;

        int                     (*hp_accept)(struct handshake_req *req,
                                             struct genl_info *info, int fd);
        void                    (*hp_done)(struct handshake_req *req,
                                           unsigned int status,
                                           struct genl_info *info);
        void                    (*hp_destroy)(struct handshake_req *req);
};

enum hp_flags_bits {
        HANDSHAKE_F_PROTO_NOTIFY,
};

/* alert.c */
int tls_alert_send(struct socket *sock, u8 level, u8 description);

/* netlink.c */
int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,
                          gfp_t flags);
struct nlmsghdr *handshake_genl_put(struct sk_buff *msg,
                                    struct genl_info *info);
struct handshake_net *handshake_pernet(struct net *net);

/* request.c */
struct handshake_req *handshake_req_alloc(const struct handshake_proto *proto,
                                          gfp_t flags);
int handshake_req_hash_init(void);
void handshake_req_hash_destroy(void);
void *handshake_req_private(struct handshake_req *req);
struct handshake_req *handshake_req_hash_lookup(struct sock *sk);
struct handshake_req *handshake_req_next(struct handshake_net *hn, int class);
int handshake_req_submit(struct socket *sock, struct handshake_req *req,
                         gfp_t flags);
void handshake_complete(struct handshake_req *req, unsigned int status,
                        struct genl_info *info);
bool handshake_req_cancel(struct sock *sk);

#endif /* _INTERNAL_HANDSHAKE_H */