send.h

   1 /*
   2  * Copyright (C) 2005-2010 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file send.h Sender-related defines and structures. */
   8
   9 /** The sender subcommands. */
  10 enum {SENDER_ADD, SENDER_DELETE, SENDER_ALLOW, SENDER_DENY, SENDER_ON, SENDER_OFF, NUM_SENDER_CMDS};
  11
  12 /**
  13  * Each paraslash sender may register arbitrary many clients to the virtual
  14  * streaming system, possibly with varying fec parameters. In order to do so,
  15  * it must allocate a \a fec_client_parms structure and pass it to \ref
  16  * add_fec_client.
  17  *
  18  * Clients are automatically removed from that list by the vss if an error
  19  * occurs, or if the sender requests deletion of a client by calling \ref
  20  * vss_del_fec_client().
  21  */
  22 struct fec_client;
  23 struct sender_client;
  24
  25 /** FEC parameters requested by FEC clients. */
  26 struct fec_client_parms {
  27         /** Number of data slices plus redundant slices. */
  28         uint8_t slices_per_group;
  29         /** Number of slices minus number of redundant slices. */
  30         uint8_t data_slices_per_group;
  31         /** Maximal number of bytes per slice, initially zero. */
  32         uint16_t max_slice_bytes;
  33         /**
  34          * Transport-layer initialisation for FEC support.
  35          *
  36          * This optional function serves (a) to make the transport layer
  37          * ready to send FEC slices and (b) to determine the Maximum
  38          * Packet Size (MPS) supported by the connection. The MPS value
  39          * determines the largest payload size. This value is used to
  40          * send FEC slices that are not larger than the path MTU, to avoid
  41          * fragmentation and to maximize packet utilization. The user can
  42          * alternatively specify a slice size of up to this value.
  43          */
  44         int (*init_fec)(struct sender_client *sc);
  45         /** Push out FEC-encoded packets */
  46         int (*send_fec)(struct sender_client *sc, char *buf, size_t len);
  47 };
  48
  49 /**
  50  * Describes one supported sender of para_server.
  51  *
  52  * \sa http_send.c udp_send.c, dccp_send.c.
  53  */
  54 struct sender {
  55         /** The name of the sender. */
  56         const char *name;
  57         /**
  58          * The init function of this sender.
  59          *
  60          * It must fill in all function pointers of \a s as well as the \a
  61          * client_cmds array, see below. It should also do all necessary
  62          * preparations to init this sending facility, for example it could
  63          * open a tcp port.
  64          */
  65         void (*init)(struct sender *s);
  66         /**
  67          * Return the help text of this sender.
  68          *
  69          * The result must be dynamically allocated and is freed by the caller.
  70          */
  71         char* (*help)(void);
  72         /**
  73          * Return current status info about this sender.
  74          *
  75          * The result must be dynamically allocated and is freed by the caller.
  76          */
  77         char* (*info)(void);
  78         /**
  79          * The send-hook.
  80          *
  81          * It gets called whenever para_server is playing and the current
  82          * audio format handler indicates that another chunk of data should
  83          * be sent now. The two parameters \a current_chunk and \a chunks_sent
  84          * only differ if the stream was repositioned by the \a ff or \a jmp
  85          * command. Of course, \a buf is a pointer to the chunk of data which
  86          * should be sent, and \a len is the length of this buffer.
  87          */
  88         void (*send)(long unsigned current_chunk, long unsigned chunks_sent,
  89                 const char *buf, size_t len, const char *header_buf,
  90                 size_t header_len);
  91
  92         /**
  93          * Obtain the FEC parameters of a FEC client.
  94          *
  95          * This is called once by vss.c at the beginning of a stream. Senders
  96          * are supposed to set \a fcp to a struct which is suitable for the FEC
  97          * client identified by \a private_data.
  98          */
  99         int (*open)(void *client, struct fec_client_parms **fcp);
 100         /**
 101          * Send the next slice to a FEC client.
 102          *
 103          * Called by vss.c when the next slice should be sent to the FEC client
 104          * identified by \a private_data, the pointer which was previously
 105          * passed to vss_add_fec_target().
 106          */
 107         int (*send_fec)(char *buf, size_t num_bytes, void *private_data);
 108         /**
 109          * Add file descriptors to fd_sets.
 110          *
 111          * The pre_select function of each supported sender is called just before
 112          * para_server enters its main select loop. Each sender may add its own
 113          * file descriptors to the \a rfds or the \a wfds set.
 114          *
 115          * If a file descriptor was added, \a max_fileno must be increased by
 116          * this function, if necessary.
 117          *
 118          * \sa select(2).
 119          */
 120         void (*pre_select)(int *max_fileno, fd_set *rfds, fd_set *wfds);
 121         /**
 122          * Handle the file descriptors which are ready for I/O.
 123          *
 124          * If the pre_select hook added one ore more file descriptors to the
 125          * read or write set, this is the hook to check the result and do any
 126          * I/O on those descriptors which are ready for reading/writing.
 127          */
 128         void (*post_select)(fd_set *rfds, fd_set *wfds);
 129         /**
 130          * Terminate all connected clients.
 131          *
 132          * This is called e.g. if the stop command was executed. It should make
 133          * the clients aware of the end-of-file condition.
 134          */
 135         void (*shutdown_clients)(void);
 136         /**
 137          * Array of function pointers for the sender subcommands.
 138          *
 139          * Each sender may implement any subset of the sender commands by
 140          * filling in the appropriate function pointer in the array. A \p NULL
 141          * pointer means this command is not implemented by this sender.
 142          */
 143         int (*client_cmds[NUM_SENDER_CMDS])(struct sender_command_data*);
 144 };
 145
 146 /** Describes one client, connected to a paraslash sender. */
 147 struct sender_client {
 148         /** The file descriptor of the client. */
 149         int fd;
 150         /** The socket "name" of the client. */
 151         char *name;
 152         /** The position of this client in the client list. */
 153         struct list_head node;
 154         /** Non-zero if audio file header has been sent. */
 155         int header_sent;
 156         /** The list of pending chunks for this client. */
 157         struct chunk_queue *cq;
 158         /** Data specific to the particular sender. */
 159         void *private_data;
 160 };
 161
 162 /** Describes the current status of one paraslash sender. */
 163 struct sender_status {
 164         /** The file descriptor of the socket this sender is listening on. */
 165         int listen_fd;
 166         /** The TCP/DCCP port used by this sender. */
 167         int port;
 168         /** The current number of simultaneous connections. */
 169         int num_clients;
 170         /** The maximal number of simultaneous connections. */
 171         int max_clients;
 172         /** Whether the access control list is a whitelist. */
 173         int default_deny;
 174         /** The whitelist/blacklist. */
 175         struct list_head acl;
 176         /** The list of connected clients. */
 177         struct list_head client_list;
 178 };
 179
 180 void shutdown_client(struct sender_client *sc, struct sender_status *ss);
 181 void shutdown_clients(struct sender_status *ss);
 182 void send_chunk(struct sender_client *sc, struct sender_status *ss,
 183                 size_t max_bytes_per_write, long unsigned current_chunk,
 184                 const char *buf, size_t len, const char *header_buf,
 185                 size_t header_len);
 186 void init_sender_status(struct sender_status *ss, char **access_arg, int num_access_args,
 187         int port, int max_clients, int default_deny);
 188 char *get_sender_info(struct sender_status *ss, const char *name);
 189
 190 void generic_com_allow(struct sender_command_data *scd,
 191                 struct sender_status *ss);
 192 void generic_com_deny(struct sender_command_data *scd,
 193                 struct sender_status *ss);
 194 int generic_com_on(struct sender_status *ss, unsigned protocol);
 195 void generic_com_off(struct sender_status *ss);
 196 char *generic_sender_help(void);
 197 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds);
 198 int send_queued_chunks(int fd, struct chunk_queue *cq,
 199                 size_t max_bytes_per_write);
 200 int parse_fec_url(const char *arg, struct sender_command_data *scd);