/*
 * VMware vSockets Driver
 *
 * Copyright (C) 2007-2013 VMware, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation version 2 and no later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#ifndef __AF_VSOCK_H__
#define __AF_VSOCK_H__

#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/vm_sockets.h>

#include "vsock_addr.h"

/* vsock-specific sock->sk_state constants */
#define VSOCK_SS_LISTEN 255

#define LAST_RESERVED_PORT 1023

#define vsock_sk(__sk)    ((struct vsock_sock *)__sk)
#define sk_vsock(__vsk)   (&(__vsk)->sk)

struct vsock_sock {
	/* sk must be the first member. */
	struct sock sk;
	struct sockaddr_vm local_addr;
	struct sockaddr_vm remote_addr;
	/* Links for the global tables of bound and connected sockets. */
	struct list_head bound_table;
	struct list_head connected_table;
	/* Accessed without the socket lock held. This means it can never be
	 * modified outsided of socket create or destruct.
	 */
	bool trusted;
	bool cached_peer_allow_dgram;	/* Dgram communication allowed to
					 * cached peer?
					 */
	u32 cached_peer;  /* Context ID of last dgram destination check. */
	const struct cred *owner;
	/* Rest are SOCK_STREAM only. */
	long connect_timeout;
	/* Listening socket that this came from. */
	struct sock *listener;
	/* Used for pending list and accept queue during connection handshake.
	 * The listening socket is the head for both lists.  Sockets created
	 * for connection requests are placed in the pending list until they
	 * are connected, at which point they are put in the accept queue list
	 * so they can be accepted in accept().  If accept() cannot accept the
	 * connection, it is marked as rejected so the cleanup function knows
	 * to clean up the socket.
	 */
	struct list_head pending_links;
	struct list_head accept_queue;
	bool rejected;
	struct delayed_work dwork;
	struct delayed_work close_work;
	bool close_work_scheduled;
	u32 peer_shutdown;
	bool sent_request;
	bool ignore_connecting_rst;

	/* Private to transport. */
	void *trans;
};

s64 vsock_stream_has_data(struct vsock_sock *vsk);
s64 vsock_stream_has_space(struct vsock_sock *vsk);
void vsock_pending_work(struct work_struct *work);
struct sock *__vsock_create(struct net *net,
			    struct socket *sock,
			    struct sock *parent,
			    gfp_t priority, unsigned short type, int kern);

/**** TRANSPORT ****/

struct vsock_transport_recv_notify_data {
	u64 data1; /* Transport-defined. */
	u64 data2; /* Transport-defined. */
	bool notify_on_block;
};

struct vsock_transport_send_notify_data {
	u64 data1; /* Transport-defined. */
	u64 data2; /* Transport-defined. */
};

struct vsock_transport {
	/* Initialize/tear-down socket. */
	int (*init)(struct vsock_sock *, struct vsock_sock *);
	void (*destruct)(struct vsock_sock *);
	void (*release)(struct vsock_sock *);

	/* Connections. */
	int (*connect)(struct vsock_sock *);

	/* DGRAM. */
	int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
	int (*dgram_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
			     size_t len, int flags);
	int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
			     struct msghdr *, size_t len);
	bool (*dgram_allow)(u32 cid, u32 port);

	/* STREAM. */
	/* TODO: stream_bind() */
	ssize_t (*stream_dequeue)(struct vsock_sock *, struct msghdr *,
				  size_t len, int flags);
	ssize_t (*stream_enqueue)(struct vsock_sock *, struct msghdr *,
				  size_t len);
	s64 (*stream_has_data)(struct vsock_sock *);
	s64 (*stream_has_space)(struct vsock_sock *);
	u64 (*stream_rcvhiwat)(struct vsock_sock *);
	bool (*stream_is_active)(struct vsock_sock *);
	bool (*stream_allow)(u32 cid, u32 port);

	/* Notification. */
	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
	int (*notify_poll_out)(struct vsock_sock *, size_t, bool *);
	int (*notify_recv_init)(struct vsock_sock *, size_t,
		struct vsock_transport_recv_notify_data *);
	int (*notify_recv_pre_block)(struct vsock_sock *, size_t,
		struct vsock_transport_recv_notify_data *);
	int (*notify_recv_pre_dequeue)(struct vsock_sock *, size_t,
		struct vsock_transport_recv_notify_data *);
	int (*notify_recv_post_dequeue)(struct vsock_sock *, size_t,
		ssize_t, bool, struct vsock_transport_recv_notify_data *);
	int (*notify_send_init)(struct vsock_sock *,
		struct vsock_transport_send_notify_data *);
	int (*notify_send_pre_block)(struct vsock_sock *,
		struct vsock_transport_send_notify_data *);
	int (*notify_send_pre_enqueue)(struct vsock_sock *,
		struct vsock_transport_send_notify_data *);
	int (*notify_send_post_enqueue)(struct vsock_sock *, ssize_t,
		struct vsock_transport_send_notify_data *);

	/* Shutdown. */
	int (*shutdown)(struct vsock_sock *, int);

	/* Buffer sizes. */
	void (*set_buffer_size)(struct vsock_sock *, u64);
	void (*set_min_buffer_size)(struct vsock_sock *, u64);
	void (*set_max_buffer_size)(struct vsock_sock *, u64);
	u64 (*get_buffer_size)(struct vsock_sock *);
	u64 (*get_min_buffer_size)(struct vsock_sock *);
	u64 (*get_max_buffer_size)(struct vsock_sock *);

	/* Addressing. */
	u32 (*get_local_cid)(void);
};

/**** CORE ****/

int __vsock_core_init(const struct vsock_transport *t, struct module *owner);
static inline int vsock_core_init(const struct vsock_transport *t)
{
	return __vsock_core_init(t, THIS_MODULE);
}
void vsock_core_exit(void);

/* The transport may downcast this to access transport-specific functions */
const struct vsock_transport *vsock_core_get_transport(void);

/**** UTILS ****/

void vsock_release_pending(struct sock *pending);
void vsock_add_pending(struct sock *listener, struct sock *pending);
void vsock_remove_pending(struct sock *listener, struct sock *pending);
void vsock_enqueue_accept(struct sock *listener, struct sock *connected);
void vsock_insert_connected(struct vsock_sock *vsk);
void vsock_remove_bound(struct vsock_sock *vsk);
void vsock_remove_connected(struct vsock_sock *vsk);
struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr);
struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
					 struct sockaddr_vm *dst);
void vsock_remove_sock(struct vsock_sock *vsk);
void vsock_for_each_connected_socket(void (*fn)(struct sock *sk));

#endif /* __AF_VSOCK_H__ */