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

#ifndef __NET_PSP_H
#define __NET_PSP_H

#include <linux/mutex.h>
#include <linux/refcount.h>

struct netlink_ext_ack;

#define PSP_DEFAULT_UDP_PORT    1000

struct psphdr {
        u8      nexthdr;
        u8      hdrlen;
        u8      crypt_offset;
        u8      verfl;
        __be32  spi;
        __be64  iv;
        __be64  vc[]; /* optional */
};

#define PSP_ENCAP_HLEN (sizeof(struct udphdr) + sizeof(struct psphdr))

#define PSP_SPI_KEY_ID          GENMASK(30, 0)
#define PSP_SPI_KEY_PHASE       BIT(31)

#define PSPHDR_CRYPT_OFFSET     GENMASK(5, 0)

#define PSPHDR_VERFL_SAMPLE     BIT(7)
#define PSPHDR_VERFL_DROP       BIT(6)
#define PSPHDR_VERFL_VERSION    GENMASK(5, 2)
#define PSPHDR_VERFL_VIRT       BIT(1)
#define PSPHDR_VERFL_ONE        BIT(0)

#define PSP_HDRLEN_NOOPT        ((sizeof(struct psphdr) - 8) / 8)

/**
 * struct psp_dev_config - PSP device configuration
 * @versions: PSP versions enabled on the device
 */
struct psp_dev_config {
        u32 versions;
};

/**
 * struct psp_dev - PSP device struct
 * @main_netdev: original netdevice of this PSP device
 * @ops:        driver callbacks
 * @caps:       device capabilities
 * @drv_priv:   driver priv pointer
 * @lock:       instance lock, protects all fields
 * @refcnt:     reference count for the instance
 * @id:         instance id
 * @generation: current generation of the device key
 * @config:     current device configuration
 * @active_assocs:      list of registered associations
 * @prev_assocs:        associations which use old (but still usable)
 *                      device key
 * @stale_assocs:       associations which use a rotated out key
 *
 * @stats:      statistics maintained by the core
 * @stats.rotations:    See stats attr key-rotations
 * @stats.stales:       See stats attr stale-events
 *
 * @rcu:        RCU head for freeing the structure
 */
struct psp_dev {
        struct net_device *main_netdev;

        struct psp_dev_ops *ops;
        struct psp_dev_caps *caps;
        void *drv_priv;

        struct mutex lock;
        refcount_t refcnt;

        u32 id;

        u8 generation;

        struct psp_dev_config config;

        struct list_head active_assocs;
        struct list_head prev_assocs;
        struct list_head stale_assocs;

        struct {
                unsigned long rotations;
                unsigned long stales;
        } stats;

        struct rcu_head rcu;
};

#define PSP_GEN_VALID_MASK      0x7f

/**
 * struct psp_dev_caps - PSP device capabilities
 */
struct psp_dev_caps {
        /**
         * @versions: mask of supported PSP versions
         * Set this field to 0 to indicate PSP is not supported at all.
         */
        u32 versions;

        /**
         * @assoc_drv_spc: size of driver-specific state in Tx assoc
         * Determines the size of struct psp_assoc::drv_data
         */
        u32 assoc_drv_spc;
};

#define PSP_MAX_KEY     32

#define PSP_HDR_SIZE    16      /* We don't support optional fields, yet */
#define PSP_TRL_SIZE    16      /* AES-GCM/GMAC trailer size */

struct psp_skb_ext {
        __be32 spi;
        u16 dev_id;
        u8 generation;
        u8 version;
};

struct psp_key_parsed {
        __be32 spi;
        u8 key[PSP_MAX_KEY];
};

struct psp_assoc {
        struct psp_dev *psd;

        u16 dev_id;
        u8 generation;
        u8 version;
        u8 peer_tx;

        u32 upgrade_seq;

        struct psp_key_parsed tx;
        struct psp_key_parsed rx;

        refcount_t refcnt;
        struct rcu_head rcu;
        struct work_struct work;
        struct list_head assocs_list;

        u8 drv_data[] __aligned(8);
};

struct psp_dev_stats {
        union {
                struct {
                        u64 rx_packets;
                        u64 rx_bytes;
                        u64 rx_auth_fail;
                        u64 rx_error;
                        u64 rx_bad;
                        u64 tx_packets;
                        u64 tx_bytes;
                        u64 tx_error;
                };
                DECLARE_FLEX_ARRAY(u64, required);
        };
};

/**
 * struct psp_dev_ops - netdev driver facing PSP callbacks
 */
struct psp_dev_ops {
        /**
         * @set_config: set configuration of a PSP device
         * Driver can inspect @psd->config for the previous configuration.
         * Core will update @psd->config with @config on success.
         */
        int (*set_config)(struct psp_dev *psd, struct psp_dev_config *conf,
                          struct netlink_ext_ack *extack);

        /**
         * @key_rotate: rotate the device key
         */
        int (*key_rotate)(struct psp_dev *psd, struct netlink_ext_ack *extack);

        /**
         * @rx_spi_alloc: allocate an Rx SPI+key pair
         * Allocate an Rx SPI and resulting derived key.
         * This key should remain valid until key rotation.
         */
        int (*rx_spi_alloc)(struct psp_dev *psd, u32 version,
                            struct psp_key_parsed *assoc,
                            struct netlink_ext_ack *extack);

        /**
         * @tx_key_add: add a Tx key to the device
         * Install an association in the device. Core will allocate space
         * for the driver to use at drv_data.
         */
        int (*tx_key_add)(struct psp_dev *psd, struct psp_assoc *pas,
                          struct netlink_ext_ack *extack);
        /**
         * @tx_key_del: remove a Tx key from the device
         * Remove an association from the device.
         */
        void (*tx_key_del)(struct psp_dev *psd, struct psp_assoc *pas);

        /**
         * @get_stats: get statistics from the device
         * Stats required by the spec must be maintained and filled in.
         * Stats must be filled in member-by-member, never memset the struct.
         */
        void (*get_stats)(struct psp_dev *psd, struct psp_dev_stats *stats);
};

#endif /* __NET_PSP_H */