contrib/ivshmem-client/ivshmem-client.h

   1 /*
   2  * Copyright 6WIND S.A., 2014
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or
   5  * (at your option) any later version.  See the COPYING file in the
   6  * top-level directory.
   7  */
   8
   9 #ifndef IVSHMEM_CLIENT_H
  10 #define IVSHMEM_CLIENT_H
  11
  12 /**
  13  * This file provides helper to implement an ivshmem client. It is used
  14  * on the host to ask QEMU to send an interrupt to an ivshmem PCI device in a
  15  * guest. QEMU also implements an ivshmem client similar to this one, they both
  16  * connect to an ivshmem server.
  17  *
  18  * A standalone ivshmem client based on this file is provided for debug/test
  19  * purposes.
  20  */
  21
  22 #include <sys/select.h>
  23
  24 #include "qemu/queue.h"
  25 #include "hw/misc/ivshmem.h"
  26
  27 /**
  28  * Maximum number of notification vectors supported by the client
  29  */
  30 #define IVSHMEM_CLIENT_MAX_VECTORS 64
  31
  32 /**
  33  * Structure storing a peer
  34  *
  35  * Each time a client connects to an ivshmem server, it is advertised to
  36  * all connected clients through the unix socket. When our ivshmem
  37  * client receives a notification, it creates a IvshmemClientPeer
  38  * structure to store the infos of this peer.
  39  *
  40  * This structure is also used to store the information of our own
  41  * client in (IvshmemClient)->local.
  42  */
  43 typedef struct IvshmemClientPeer {
  44     QTAILQ_ENTRY(IvshmemClientPeer) next;    /**< next in list*/
  45     int64_t id;                              /**< the id of the peer */
  46     int vectors[IVSHMEM_CLIENT_MAX_VECTORS]; /**< one fd per vector */
  47     unsigned vectors_count;                  /**< number of vectors */
  48 } IvshmemClientPeer;
  49
  50 typedef struct IvshmemClient IvshmemClient;
  51
  52 /**
  53  * Typedef of callback function used when our IvshmemClient receives a
  54  * notification from a peer.
  55  */
  56 typedef void (*IvshmemClientNotifCb)(
  57     const IvshmemClient *client,
  58     const IvshmemClientPeer *peer,
  59     unsigned vect, void *arg);
  60
  61 /**
  62  * Structure describing an ivshmem client
  63  *
  64  * This structure stores all information related to our client: the name
  65  * of the server unix socket, the list of peers advertised by the
  66  * server, our own client information, and a pointer the notification
  67  * callback function used when we receive a notification from a peer.
  68  */
  69 struct IvshmemClient {
  70     char unix_sock_path[PATH_MAX];      /**< path to unix sock */
  71     int sock_fd;                        /**< unix sock filedesc */
  72     int shm_fd;                         /**< shm file descriptor */
  73
  74     QTAILQ_HEAD(, IvshmemClientPeer) peer_list;    /**< list of peers */
  75     IvshmemClientPeer local;            /**< our own infos */
  76
  77     IvshmemClientNotifCb notif_cb;      /**< notification callback */
  78     void *notif_arg;                    /**< notification argument */
  79
  80     bool verbose;                       /**< true to enable debug */
  81 };
  82
  83 /**
  84  * Initialize an ivshmem client
  85  *
  86  * @client:         A pointer to an uninitialized IvshmemClient structure
  87  * @unix_sock_path: The pointer to the unix socket file name
  88  * @notif_cb:       If not NULL, the pointer to the function to be called when
  89  *                  our IvshmemClient receives a notification from a peer
  90  * @notif_arg:      Opaque pointer given as-is to the notification callback
  91  *                  function
  92  * @verbose:        True to enable debug
  93  *
  94  * Returns:         0 on success, or a negative value on error
  95  */
  96 int ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
  97                         IvshmemClientNotifCb notif_cb, void *notif_arg,
  98                         bool verbose);
  99
 100 /**
 101  * Connect to the server
 102  *
 103  * Connect to the server unix socket, and read the first initial
 104  * messages sent by the server, giving the ID of the client and the file
 105  * descriptor of the shared memory.
 106  *
 107  * @client: The ivshmem client
 108  *
 109  * Returns: 0 on success, or a negative value on error
 110  */
 111 int ivshmem_client_connect(IvshmemClient *client);
 112
 113 /**
 114  * Close connection to the server and free all peer structures
 115  *
 116  * @client: The ivshmem client
 117  */
 118 void ivshmem_client_close(IvshmemClient *client);
 119
 120 /**
 121  * Fill a fd_set with file descriptors to be monitored
 122  *
 123  * This function will fill a fd_set with all file descriptors
 124  * that must be polled (unix server socket and peers eventfd). The
 125  * function will not initialize the fd_set, it is up to the caller
 126  * to do this.
 127  *
 128  * @client: The ivshmem client
 129  * @fds:    The fd_set to be updated
 130  * @maxfd:  Must be set to the max file descriptor + 1 in fd_set. This value is
 131  *          updated if this function adds a greater fd in fd_set.
 132  */
 133 void ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds,
 134                             int *maxfd);
 135
 136 /**
 137  * Read and handle new messages
 138  *
 139  * Given a fd_set filled by select(), handle incoming messages from
 140  * server or peers.
 141  *
 142  * @client: The ivshmem client
 143  * @fds:    The fd_set containing the file descriptors to be checked. Note
 144  *          that file descriptors that are not related to our client are
 145  *          ignored.
 146  * @maxfd:  The maximum fd in fd_set, plus one.
 147  *
 148  * Returns: 0 on success, or a negative value on error
 149  */
 150 int ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd);
 151
 152 /**
 153  * Send a notification to a vector of a peer
 154  *
 155  * @client: The ivshmem client
 156  * @peer:   The peer to be notified
 157  * @vector: The number of the vector
 158  *
 159  * Returns: 0 on success, or a negative value on error
 160  */
 161 int ivshmem_client_notify(const IvshmemClient *client,
 162                           const IvshmemClientPeer *peer, unsigned vector);
 163
 164 /**
 165  * Send a notification to all vectors of a peer
 166  *
 167  * @client: The ivshmem client
 168  * @peer:   The peer to be notified
 169  *
 170  * Returns: 0 on success, or a negative value on error (at least one
 171  *          notification failed)
 172  */
 173 int ivshmem_client_notify_all_vects(const IvshmemClient *client,
 174                                     const IvshmemClientPeer *peer);
 175
 176 /**
 177  * Broadcat a notification to all vectors of all peers
 178  *
 179  * @client: The ivshmem client
 180  *
 181  * Returns: 0 on success, or a negative value on error (at least one
 182  *          notification failed)
 183  */
 184 int ivshmem_client_notify_broadcast(const IvshmemClient *client);
 185
 186 /**
 187  * Search a peer from its identifier
 188  *
 189  * Return the peer structure from its peer_id. If the given peer_id is
 190  * the local id, the function returns the local peer structure.
 191  *
 192  * @client:  The ivshmem client
 193  * @peer_id: The identifier of the peer structure
 194  *
 195  * Returns:  The peer structure, or NULL if not found
 196  */
 197 IvshmemClientPeer *
 198 ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id);
 199
 200 /**
 201  * Dump information of this ivshmem client on stdout
 202  *
 203  * Dump the id and the vectors of the given ivshmem client and the list
 204  * of its peers and their vectors on stdout.
 205  *
 206  * @client: The ivshmem client
 207  */
 208 void ivshmem_client_dump(const IvshmemClient *client);
 209
 210 #endif /* IVSHMEM_CLIENT_H */