/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright (c) Intel Corporation. All rights reserved.
 *   Copyright (c) 2020 Mellanox Technologies LTD. All rights reserved.
 */

/** \file
 * TCP socket abstraction layer
 */

#ifndef SPDK_SOCK_H
#define SPDK_SOCK_H

#include "spdk/stdinc.h"

#include "spdk/queue.h"
#include "spdk/json.h"
#include "spdk/assert.h"

#ifdef __cplusplus
extern "C" {
#endif

struct spdk_sock;
struct spdk_sock_group;

/**
 * Anywhere this struct is used, an iovec array is assumed to
 * immediately follow the last member in memory, without any
 * padding.
 *
 * A simpler implementation would be to place a 0-length array
 * of struct iovec at the end of this request. However, embedding
 * a structure that ends with a variable length array inside of
 * another structure is a GNU C extension and not standard.
 */
struct spdk_sock_request {
	/* When the request is completed, this callback will be called.
	 * On success, err will be:
	 *   - for writes: 0,
	 *   - for reads: number of bytes read.
	 * On failure: negative errno value.
	 */
	void	(*cb_fn)(void *cb_arg, int err);
	void				*cb_arg;

	/**
	 * These fields are used by the socket layer and should not be modified
	 */
	struct __sock_request_internal {
		TAILQ_ENTRY(spdk_sock_request)	link;
#ifdef DEBUG
		void				*curr_list;
#endif
		uint32_t			offset;

		/* Indicate if the whole req or part of it is sent with zerocopy */
		bool				is_zcopy;
	} internal;

	int				iovcnt;
	/* struct iovec			iov[]; */
};

#define SPDK_SOCK_REQUEST_IOV(req, i) ((struct iovec *)(((uint8_t *)req + sizeof(struct spdk_sock_request)) + (sizeof(struct iovec) * i)))

enum spdk_placement_mode {
	PLACEMENT_NONE,
	PLACEMENT_NAPI,
	PLACEMENT_CPU,
	PLACEMENT_MARK,
};

#define SPDK_TLS_VERSION_1_1 11
#define SPDK_TLS_VERSION_1_2 12
#define SPDK_TLS_VERSION_1_3 13

/**
 * SPDK socket implementation options.
 *
 * A pointer to this structure is used by spdk_sock_impl_get_opts() and spdk_sock_impl_set_opts()
 * to allow the user to request options for the socket module implementation.
 * Each socket module defines which options from this structure are applicable to the module.
 */
struct spdk_sock_impl_opts {
	/**
	 * Size of sock receive buffer. Used by posix and uring socket modules.
	 */
	uint32_t recv_buf_size;

	/**
	 * Size of sock send buffer. Used by posix and uring socket modules.
	 */
	uint32_t send_buf_size;

	/**
	 * Enable or disable receive pipe. Used by posix and uring socket modules.
	 */
	bool enable_recv_pipe;

	/**
	 * **Deprecated, please use enable_zerocopy_send_server or enable_zerocopy_send_client instead**
	 * Enable or disable use of zero copy flow on send. Used by posix socket module.
	 */
	bool enable_zerocopy_send;

	/**
	 * Enable or disable quick ACK. Used by posix and uring socket modules.
	 */
	bool enable_quickack;

	/**
	 * Enable or disable placement_id. Used by posix and uring socket modules.
	 * Valid values in the enum spdk_placement_mode.
	 */
	uint32_t enable_placement_id;

	/**
	 * Enable or disable use of zero copy flow on send for server sockets. Used by posix and uring socket modules.
	 */
	bool enable_zerocopy_send_server;

	/**
	 * Enable or disable use of zero copy flow on send for client sockets. Used by posix and uring socket modules.
	 */
	bool enable_zerocopy_send_client;

	/**
	 * Set zerocopy threshold in bytes. A consecutive sequence of requests' iovecs that fall below this
	 * threshold may be sent without zerocopy flag set.
	 */
	uint32_t zerocopy_threshold;

	/**
	 * TLS protocol version. Used by ssl socket module.
	 */
	uint32_t tls_version;

	/**
	 * Enable or disable kernel TLS. Used by ssl socket modules.
	 */
	bool enable_ktls;

	/**
	 * Set default PSK key. Used by ssl socket module.
	 */
	char *psk_key;

	/**
	 * Set default PSK identity. Used by ssl socket module.
	 */
	char *psk_identity;
};

/**
 * Spdk socket initialization options.
 *
 * A pointer to this structure will be used by spdk_sock_listen_ext() or spdk_sock_connect_ext() to
 * allow the user to request non-default options on the socket.
 */
struct spdk_sock_opts {
	/**
	 * The size of spdk_sock_opts according to the caller of this library is used for ABI
	 * compatibility.  The library uses this field to know how many fields in this
	 * structure are valid. And the library will populate any remaining fields with default values.
	 */
	size_t opts_size;

	/**
	 * The priority on the socket and default value is zero.
	 */
	int priority;

	/**
	 * Used to enable or disable zero copy on socket layer.
	 */
	bool zcopy;

	/* Hole at bytes 13-15. */
	uint8_t reserved13[3];

	/**
	 * Time in msec to wait ack until connection is closed forcefully.
	 */
	uint32_t ack_timeout;

	/* Hole at bytes 20-23. */
	uint8_t reserved[4];

	/**
	 * Socket implementation options.  If non-NULL, these will override those set by
	 * spdk_sock_impl_set_opts().  The library copies this structure internally, so the user can
	 * free it immediately after a spdk_sock_connect()/spdk_sock_listen() call.
	 */
	struct spdk_sock_impl_opts *impl_opts;

	/**
	 * Size of the impl_opts structure.
	 */
	size_t impl_opts_size;
} __attribute__((packed));
SPDK_STATIC_ASSERT(sizeof(struct spdk_sock_opts) == 40, "Incorrect size");

/**
 * Initialize the default value of opts.
 *
 * \param opts Data structure where SPDK will initialize the default sock options.
 * Users must set opts_size to sizeof(struct spdk_sock_opts).  This will ensure that the
 * libraryonly tries to fill as many fields as allocated by the caller. This allows ABI
 * compatibility with future versions of this library that may extend the spdk_sock_opts
 * structure.
 */
void spdk_sock_get_default_opts(struct spdk_sock_opts *opts);

/**
 * Get client and server addresses of the given socket.
 *
 * \param sock Socket to get address.
 * \param saddr A pointer to the buffer to hold the address of server.
 * \param slen Length of the buffer 'saddr'.
 * \param sport A pointer(May be NULL) to the buffer to hold the port info of server.
 * \param caddr A pointer to the buffer to hold the address of client.
 * \param clen Length of the buffer 'caddr'.
 * \param cport A pointer(May be NULL) to the buffer to hold the port info of server.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_getaddr(struct spdk_sock *sock, char *saddr, int slen, uint16_t *sport,
		      char *caddr, int clen, uint16_t *cport);

/**
 * Create a socket using the specific sock implementation, connect the socket
 * to the specified address and port (of the server), and then return the socket.
 * This function is used by client.
 *
 * \param ip IP address of the server.
 * \param port Port number of the server.
 * \param impl_name The sock_implementation to use, such as "posix". If impl_name is
 * specified, it will *only* try to connect on that impl. If it is NULL, it will try
 * all the sock implementations in order and uses the first sock implementation which
 * can connect.
 *
 * \return a pointer to the connected socket on success, or NULL on failure.
 */
struct spdk_sock *spdk_sock_connect(const char *ip, int port, const char *impl_name);

/**
 * Create a socket using the specific sock implementation, connect the socket
 * to the specified address and port (of the server), and then return the socket.
 * This function is used by client.
 *
 * \param ip IP address of the server.
 * \param port Port number of the server.
 * \param impl_name The sock_implementation to use, such as "posix". If impl_name is
 * specified, it will *only* try to connect on that impl. If it is NULL, it will try
 * all the sock implementations in order and uses the first sock implementation which
 * can connect.
 * \param opts The sock option pointer provided by the user which should not be NULL pointer.
 *
 * \return a pointer to the connected socket on success, or NULL on failure.
 */
struct spdk_sock *spdk_sock_connect_ext(const char *ip, int port, const char *impl_name,
					struct spdk_sock_opts *opts);

/**
 * Create a socket using the specific sock implementation, bind the socket to
 * the specified address and port and listen on the socket, and then return the socket.
 * This function is used by server.
 *
 * \param ip IP address to listen on.
 * \param port Port number.
 * \param impl_name The sock_implementation to use, such as "posix". If impl_name is
 * specified, it will *only* try to listen on that impl. If it is NULL, it will try
 * all the sock implementations in order and uses the first sock implementation which
 * can listen.
 *
 * \return a pointer to the listened socket on success, or NULL on failure.
 */
struct spdk_sock *spdk_sock_listen(const char *ip, int port, const char *impl_name);

/**
 * Create a socket using the specific sock implementation, bind the socket to
 * the specified address and port and listen on the socket, and then return the socket.
 * This function is used by server.
 *
 * \param ip IP address to listen on.
 * \param port Port number.
 * \param impl_name The sock_implementation to use, such as "posix". If impl_name is
 * specified, it will *only* try to listen on that impl. If it is NULL, it will try
 * all the sock implementations in order and uses the first sock implementation which
 * can listen.
 * \param opts The sock option pointer provided by the user, which should not be NULL pointer.
 *
 * \return a pointer to the listened socket on success, or NULL on failure.
 */
struct spdk_sock *spdk_sock_listen_ext(const char *ip, int port, const char *impl_name,
				       struct spdk_sock_opts *opts);

/**
 * Accept a new connection from a client on the specified socket and return a
 * socket structure which holds the connection.
 *
 * \param sock Listening socket.
 *
 * \return a pointer to the accepted socket on success, or NULL on failure.
 */
struct spdk_sock *spdk_sock_accept(struct spdk_sock *sock);

/**
 * Close a socket.
 *
 * \param sock Socket to close.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_close(struct spdk_sock **sock);

/**
 * Flush a socket from data gathered in previous writev_async calls.
 *
 * \param sock Socket to flush.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_flush(struct spdk_sock *sock);

/**
 * Receive a message from the given socket.
 *
 * \param sock Socket to receive message.
 * \param buf Pointer to a buffer to hold the data.
 * \param len Length of the buffer.
 *
 * \return the length of the received message on success, -1 on failure.
 */
ssize_t spdk_sock_recv(struct spdk_sock *sock, void *buf, size_t len);

/**
 * Write message to the given socket from the I/O vector array.
 *
 * \param sock Socket to write to.
 * \param iov I/O vector.
 * \param iovcnt Number of I/O vectors in the array.
 *
 * \return the length of written message on success, -1 on failure.
 */
ssize_t spdk_sock_writev(struct spdk_sock *sock, struct iovec *iov, int iovcnt);

/**
 * Write data to the given socket asynchronously, calling
 * the provided callback when the data has been written.
 *
 * \param sock Socket to write to.
 * \param req The write request to submit.
 */
void spdk_sock_writev_async(struct spdk_sock *sock, struct spdk_sock_request *req);

/**
 * Read message from the given socket to the I/O vector array.
 *
 * \param sock Socket to receive message.
 * \param iov I/O vector.
 * \param iovcnt Number of I/O vectors in the array.
 *
 * \return the length of the received message on success, -1 on failure.
 */
ssize_t spdk_sock_readv(struct spdk_sock *sock, struct iovec *iov, int iovcnt);

/**
 * Read message from the given socket asynchronously, calling the provided callback when the whole
 * buffer is filled or an error is encountered.  Only a single read request can be active at a time
 * (including synchronous reads).
 *
 * \param sock Socket to receive message.
 * \param req The read request to submit.
 */
void spdk_sock_readv_async(struct spdk_sock *sock, struct spdk_sock_request *req);

/**
 * Set the value used to specify the low water mark (in bytes) for this socket.
 *
 * \param sock Socket to set for.
 * \param nbytes Value for recvlowat.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_set_recvlowat(struct spdk_sock *sock, int nbytes);

/**
 * Set receive buffer size for the given socket.
 *
 * \param sock Socket to set buffer size for.
 * \param sz Buffer size in bytes.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_set_recvbuf(struct spdk_sock *sock, int sz);

/**
 * Set send buffer size for the given socket.
 *
 * \param sock Socket to set buffer size for.
 * \param sz Buffer size in bytes.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_set_sendbuf(struct spdk_sock *sock, int sz);

/**
 * Check whether the address of socket is ipv6.
 *
 * \param sock Socket to check.
 *
 * \return true if the address of socket is ipv6, or false otherwise.
 */
bool spdk_sock_is_ipv6(struct spdk_sock *sock);

/**
 * Check whether the address of socket is ipv4.
 *
 * \param sock Socket to check.
 *
 * \return true if the address of socket is ipv4, or false otherwise.
 */
bool spdk_sock_is_ipv4(struct spdk_sock *sock);

/**
 * Check whether the socket is currently connected.
 *
 * \param sock Socket to check
 *
 * \return true if the socket is connected or false otherwise.
 */
bool spdk_sock_is_connected(struct spdk_sock *sock);

/**
 * Callback function for spdk_sock_group_add_sock().
 *
 * \param arg Argument for the callback function.
 * \param group Socket group.
 * \param sock Socket.
 */
typedef void (*spdk_sock_cb)(void *arg, struct spdk_sock_group *group, struct spdk_sock *sock);

/**
 * Create a new socket group with user provided pointer
 *
 * \param ctx the context provided by user.
 * \return a pointer to the created group on success, or NULL on failure.
 */
struct spdk_sock_group *spdk_sock_group_create(void *ctx);

/**
 * Get the ctx of the sock group
 *
 * \param sock_group Socket group.
 * \return a pointer which is ctx of the sock_group.
 */
void *spdk_sock_group_get_ctx(struct spdk_sock_group *sock_group);


/**
 * Add a socket to the group.
 *
 * \param group Socket group.
 * \param sock Socket to add.
 * \param cb_fn Called when the operation completes.
 * \param cb_arg Argument passed to the callback function.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_group_add_sock(struct spdk_sock_group *group, struct spdk_sock *sock,
			     spdk_sock_cb cb_fn, void *cb_arg);

/**
 * Remove a socket from the group.
 *
 * \param group Socket group.
 * \param sock Socket to remove.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_group_remove_sock(struct spdk_sock_group *group, struct spdk_sock *sock);

/**
 * Poll incoming events for each registered socket.
 *
 * \param group Group to poll.
 *
 * \return the number of events on success, -1 on failure.
 */
int spdk_sock_group_poll(struct spdk_sock_group *group);

/**
 * Poll incoming events up to max_events for each registered socket.
 *
 * \param group Group to poll.
 * \param max_events Number of maximum events to poll for each socket.
 *
 * \return the number of events on success, -1 on failure.
 */
int spdk_sock_group_poll_count(struct spdk_sock_group *group, int max_events);

/**
 * Close all registered sockets of the group and then remove the group.
 *
 * \param group Group to close.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_sock_group_close(struct spdk_sock_group **group);

/**
 * Get the optimal sock group for this sock.
 *
 * \param sock The socket
 * \param group Returns the optimal sock group. If there is no optimal sock group, returns NULL.
 * \param hint When return is 0 and group is set to NULL, hint is used to set optimal sock group for the socket.
 *
 * \return 0 on success. Negated errno on failure.
 */
int spdk_sock_get_optimal_sock_group(struct spdk_sock *sock, struct spdk_sock_group **group,
				     struct spdk_sock_group *hint);

/**
 * Get current socket implementation options.
 *
 * \param impl_name The socket implementation to use, such as "posix".
 * \param opts Pointer to allocated spdk_sock_impl_opts structure that will be filled with actual values.
 * \param len On input specifies size of passed opts structure. On return it is set to actual size that was filled with values.
 *
 * \return 0 on success, -1 on failure. errno is set to indicate the reason of failure.
 */
int spdk_sock_impl_get_opts(const char *impl_name, struct spdk_sock_impl_opts *opts, size_t *len);

/**
 * Set socket implementation options.
 *
 * \param impl_name The socket implementation to use, such as "posix".
 * \param opts Pointer to allocated spdk_sock_impl_opts structure with new options values.
 * \param len Size of passed opts structure.
 *
 * \return 0 on success, -1 on failure. errno is set to indicate the reason of failure.
 */
int spdk_sock_impl_set_opts(const char *impl_name, const struct spdk_sock_impl_opts *opts,
			    size_t len);

/**
 * Set the given sock implementation to be used a default one.
 *
 * Note: passing a specific sock implementation name in some sock API functions
 * (such as @ref spdk_sock_connect, @ref spdk_sock_listen and etc) ignores the default value set by this function.
 *
 * \param impl_name The socket implementation to use, such as "posix".
 * \return 0 on success, -1 on failure. errno is set to indicate the reason of failure.
 */
int spdk_sock_set_default_impl(const char *impl_name);

/**
 * Write socket subsystem configuration into provided JSON context.
 *
 * \param w JSON write context
 */
void spdk_sock_write_config_json(struct spdk_json_write_ctx *w);

#ifdef __cplusplus
}
#endif

#endif /* SPDK_SOCK_H */