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 QTAILQ_HEAD(IvshmemClientPeerList, IvshmemClientPeer);
  50
  51 typedef struct IvshmemClientPeerList IvshmemClientPeerList;
  52 typedef struct IvshmemClient IvshmemClient;
  53
  54 /**
  55  * Typedef of callback function used when our IvshmemClient receives a
  56  * notification from a peer.
  57  */
  58 typedef void (*IvshmemClientNotifCb)(
  59     const IvshmemClient *client,
  60     const IvshmemClientPeer *peer,
  61     unsigned vect, void *arg);
  62
  63 /**
  64  * Structure describing an ivshmem client
  65  *
  66  * This structure stores all information related to our client: the name
  67  * of the server unix socket, the list of peers advertised by the
  68  * server, our own client information, and a pointer the notification
  69  * callback function used when we receive a notification from a peer.
  70  */
  71 struct IvshmemClient {
  72     char unix_sock_path[PATH_MAX];      /**< path to unix sock */
  73     int sock_fd;                        /**< unix sock filedesc */
  74     int shm_fd;                         /**< shm file descriptor */
  75
  76     IvshmemClientPeerList peer_list;    /**< list of peers */
  77     IvshmemClientPeer local;            /**< our own infos */
  78
  79     IvshmemClientNotifCb notif_cb;      /**< notification callback */
  80     void *notif_arg;                    /**< notification argument */
  81
  82     bool verbose;                       /**< true to enable debug */
  83 };
  84
  85 /**
  86  * Initialize an ivshmem client
  87  *
  88  * @client:         A pointer to an uninitialized IvshmemClient structure
  89  * @unix_sock_path: The pointer to the unix socket file name
  90  * @notif_cb:       If not NULL, the pointer to the function to be called when
  91  *                  our IvshmemClient receives a notification from a peer
  92  * @notif_arg:      Opaque pointer given as-is to the notification callback
  93  *                  function
  94  * @verbose:        True to enable debug
  95  *
  96  * Returns:         0 on success, or a negative value on error
  97  */
  98 int ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
  99                         IvshmemClientNotifCb notif_cb, void *notif_arg,
 100                         bool verbose);
 101
 102 /**
 103  * Connect to the server
 104  *
 105  * Connect to the server unix socket, and read the first initial
 106  * messages sent by the server, giving the ID of the client and the file
 107  * descriptor of the shared memory.
 108  *
 109  * @client: The ivshmem client
 110  *
 111  * Returns: 0 on success, or a negative value on error
 112  */
 113 int ivshmem_client_connect(IvshmemClient *client);
 114
 115 /**
 116  * Close connection to the server and free all peer structures
 117  *
 118  * @client: The ivshmem client
 119  */
 120 void ivshmem_client_close(IvshmemClient *client);
 121
 122 /**
 123  * Fill a fd_set with file descriptors to be monitored
 124  *
 125  * This function will fill a fd_set with all file descriptors
 126  * that must be polled (unix server socket and peers eventfd). The
 127  * function will not initialize the fd_set, it is up to the caller
 128  * to do this.
 129  *
 130  * @client: The ivshmem client
 131  * @fds:    The fd_set to be updated
 132  * @maxfd:  Must be set to the max file descriptor + 1 in fd_set. This value is
 133  *          updated if this function adds a greater fd in fd_set.
 134  */
 135 void ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds,
 136                             int *maxfd);
 137
 138 /**
 139  * Read and handle new messages
 140  *
 141  * Given a fd_set filled by select(), handle incoming messages from
 142  * server or peers.
 143  *
 144  * @client: The ivshmem client
 145  * @fds:    The fd_set containing the file descriptors to be checked. Note
 146  *          that file descriptors that are not related to our client are
 147  *          ignored.
 148  * @maxfd:  The maximum fd in fd_set, plus one.
 149  *
 150  * Returns: 0 on success, or a negative value on error
 151  */
 152 int ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd);
 153
 154 /**
 155  * Send a notification to a vector of a peer
 156  *
 157  * @client: The ivshmem client
 158  * @peer:   The peer to be notified
 159  * @vector: The number of the vector
 160  *
 161  * Returns: 0 on success, or a negative value on error
 162  */
 163 int ivshmem_client_notify(const IvshmemClient *client,
 164                           const IvshmemClientPeer *peer, unsigned vector);
 165
 166 /**
 167  * Send a notification to all vectors of a peer
 168  *
 169  * @client: The ivshmem client
 170  * @peer:   The peer to be notified
 171  *
 172  * Returns: 0 on success, or a negative value on error (at least one
 173  *          notification failed)
 174  */
 175 int ivshmem_client_notify_all_vects(const IvshmemClient *client,
 176                                     const IvshmemClientPeer *peer);
 177
 178 /**
 179  * Broadcat a notification to all vectors of all peers
 180  *
 181  * @client: The ivshmem client
 182  *
 183  * Returns: 0 on success, or a negative value on error (at least one
 184  *          notification failed)
 185  */
 186 int ivshmem_client_notify_broadcast(const IvshmemClient *client);
 187
 188 /**
 189  * Search a peer from its identifier
 190  *
 191  * Return the peer structure from its peer_id. If the given peer_id is
 192  * the local id, the function returns the local peer structure.
 193  *
 194  * @client:  The ivshmem client
 195  * @peer_id: The identifier of the peer structure
 196  *
 197  * Returns:  The peer structure, or NULL if not found
 198  */
 199 IvshmemClientPeer *
 200 ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id);
 201
 202 /**
 203  * Dump information of this ivshmem client on stdout
 204  *
 205  * Dump the id and the vectors of the given ivshmem client and the list
 206  * of its peers and their vectors on stdout.
 207  *
 208  * @client: The ivshmem client
 209  */
 210 void ivshmem_client_dump(const IvshmemClient *client);
 211
 212 #endif /* IVSHMEM_CLIENT_H */