/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * VMware vSockets Driver
 *
 * Copyright (C) 2007-2013 VMware, Inc. All rights reserved.
 */

#ifndef __AF_VSOCK_H__
#define __AF_VSOCK_H__

#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <net/netns/vsock.h>
#include <net/sock.h>
#include <uapi/linux/vm_sockets.h>

#include "vsock_addr.h"

#define LAST_RESERVED_PORT 1023

#define VSOCK_HASH_SIZE         251
extern struct list_head vsock_bind_table[VSOCK_HASH_SIZE + 1];
extern struct list_head vsock_connected_table[VSOCK_HASH_SIZE];
extern spinlock_t vsock_table_lock;

#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;
        const struct vsock_transport *transport;
        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 connect_work;
        struct delayed_work pending_work;
        struct delayed_work close_work;
        bool close_work_scheduled;
        u32 peer_shutdown;
        bool sent_request;
        bool ignore_connecting_rst;

        /* Protected by lock_sock(sk) */
        u64 buffer_size;
        u64 buffer_min_size;
        u64 buffer_max_size;

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

s64 vsock_connectible_has_data(struct vsock_sock *vsk);
s64 vsock_stream_has_data(struct vsock_sock *vsk);
s64 vsock_stream_has_space(struct vsock_sock *vsk);
struct sock *vsock_create_connected(struct sock *parent);
void vsock_data_ready(struct sock *sk);

/**** 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. */
};

/* Transport features flags */
/* Transport provides host->guest communication */
#define VSOCK_TRANSPORT_F_H2G           0x00000001
/* Transport provides guest->host communication */
#define VSOCK_TRANSPORT_F_G2H           0x00000002
/* Transport provides DGRAM communication */
#define VSOCK_TRANSPORT_F_DGRAM         0x00000004
/* Transport provides local (loopback) communication */
#define VSOCK_TRANSPORT_F_LOCAL         0x00000008

struct vsock_transport {
        struct module *module;

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

        /* Cancel all pending packets sent on vsock. */
        int (*cancel_pkt)(struct vsock_sock *vsk);

        /* 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)(struct vsock_sock *vsk, 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)(struct vsock_sock *vsk, u32 cid, u32 port);

        /* SEQ_PACKET. */
        ssize_t (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
                                     int flags);
        int (*seqpacket_enqueue)(struct vsock_sock *vsk, struct msghdr *msg,
                                 size_t len);
        bool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);
        u32 (*seqpacket_has_data)(struct vsock_sock *vsk);

        /* 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 *);
        /* sk_lock held by the caller */
        void (*notify_buffer_size)(struct vsock_sock *, u64 *);
        int (*notify_set_rcvlowat)(struct vsock_sock *vsk, int val);

        /* SIOCOUTQ ioctl */
        ssize_t (*unsent_bytes)(struct vsock_sock *vsk);

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

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

        /* Read a single skb */
        int (*read_skb)(struct vsock_sock *, skb_read_actor_t);

        /* Zero-copy. */
        bool (*msgzerocopy_allow)(void);
};

/**** CORE ****/

int vsock_core_register(const struct vsock_transport *t, int features);
void vsock_core_unregister(const struct vsock_transport *t);

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

/**** UTILS ****/

/* vsock_table_lock must be held */
static inline bool __vsock_in_bound_table(struct vsock_sock *vsk)
{
        return !list_empty(&vsk->bound_table);
}

/* vsock_table_lock must be held */
static inline bool __vsock_in_connected_table(struct vsock_sock *vsk)
{
        return !list_empty(&vsk->connected_table);
}

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);
struct sock *vsock_find_bound_socket_net(struct sockaddr_vm *addr,
                                         struct net *net);
struct sock *vsock_find_connected_socket_net(struct sockaddr_vm *src,
                                             struct sockaddr_vm *dst,
                                             struct net *net);
void vsock_remove_sock(struct vsock_sock *vsk);
void vsock_for_each_connected_socket(struct vsock_transport *transport,
                                     void (*fn)(struct sock *sk));
int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
bool vsock_find_cid(unsigned int cid);
void vsock_linger(struct sock *sk);

/**** TAP ****/

struct vsock_tap {
        struct net_device *dev;
        struct module *module;
        struct list_head list;
};

int vsock_add_tap(struct vsock_tap *vt);
int vsock_remove_tap(struct vsock_tap *vt);
void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
int __vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
                                int flags);
int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
                              int flags);
int __vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
                          size_t len, int flags);
int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
                        size_t len, int flags);

extern struct proto vsock_proto;
#ifdef CONFIG_BPF_SYSCALL
int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
void __init vsock_bpf_build_proto(void);
#else
static inline void __init vsock_bpf_build_proto(void)
{}
#endif

static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
{
        return t->msgzerocopy_allow && t->msgzerocopy_allow();
}

static inline enum vsock_net_mode vsock_net_mode(struct net *net)
{
        if (!net)
                return VSOCK_NET_MODE_GLOBAL;

        return READ_ONCE(net->vsock.mode);
}

static inline bool vsock_net_mode_global(struct vsock_sock *vsk)
{
        return vsock_net_mode(sock_net(sk_vsock(vsk))) == VSOCK_NET_MODE_GLOBAL;
}

static inline bool vsock_net_set_child_mode(struct net *net,
                                            enum vsock_net_mode mode)
{
        int new_locked = mode + 1;
        int old_locked = 0; /* unlocked */

        if (try_cmpxchg(&net->vsock.child_ns_mode_locked,
                        &old_locked, new_locked)) {
                WRITE_ONCE(net->vsock.child_ns_mode, mode);
                return true;
        }

        return old_locked == new_locked;
}

static inline enum vsock_net_mode vsock_net_child_mode(struct net *net)
{
        return READ_ONCE(net->vsock.child_ns_mode);
}

/* Return true if two namespaces pass the mode rules. Otherwise, return false.
 *
 * A NULL namespace is treated as VSOCK_NET_MODE_GLOBAL.
 *
 * Read more about modes in the comment header of net/vmw_vsock/af_vsock.c.
 */
static inline bool vsock_net_check_mode(struct net *ns0, struct net *ns1)
{
        enum vsock_net_mode mode0, mode1;

        /* Any vsocks within the same network namespace are always reachable,
         * regardless of the mode.
         */
        if (net_eq(ns0, ns1))
                return true;

        mode0 = vsock_net_mode(ns0);
        mode1 = vsock_net_mode(ns1);

        /* Different namespaces are only reachable if they are both
         * global mode.
         */
        return mode0 == VSOCK_NET_MODE_GLOBAL && mode0 == mode1;
}
#endif /* __AF_VSOCK_H__ */