send.h

   1 /*
   2  * Copyright (C) 2005-2014 Andre Noll <maan@tuebingen.mpg.de>
   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_subcommand {
  11         SENDER_ADD, /**< Add a target (udp only). */
  12         SENDER_DELETE, /**< Delete a target (udp only). */
  13         SENDER_ALLOW, /**< Allow connections from given IP address(es). */
  14         SENDER_DENY, /**< Deny connections from given IP address(es). */
  15         SENDER_ON, /**< Activate the sender. */
  16         SENDER_OFF, /**< Deactivate the sender. */
  17         NUM_SENDER_CMDS /**< Used as array size in struct \ref sender. */
  18 };
  19
  20 /**
  21  * Describes one supported sender of para_server.
  22  *
  23  * \sa http_send.c udp_send.c, dccp_send.c.
  24  */
  25 struct sender {
  26         /** The name of the sender. */
  27         const char *name;
  28         /**
  29          * The init function of this sender.
  30          *
  31          * It must fill in all function pointers of \a s as well as the \a
  32          * client_cmds array, see below. It should also do all necessary
  33          * preparations to init this sending facility, for example it could
  34          * open a tcp port.
  35          */
  36         void (*init)(struct sender *s);
  37         /**
  38          * Return the help text of this sender.
  39          *
  40          * The result must be dynamically allocated and is freed by the caller.
  41          */
  42         char* (*help)(void);
  43         /**
  44          * Return current status info about this sender.
  45          *
  46          * The result must be dynamically allocated and is freed by the caller.
  47          */
  48         char* (*status)(void);
  49         /**
  50          * The send-hook.
  51          *
  52          * It gets called whenever para_server is playing and the current
  53          * audio format handler indicates that another chunk of data should
  54          * be sent now. The two parameters \a current_chunk and \a chunks_sent
  55          * only differ if the stream was repositioned by the \a ff or \a jmp
  56          * command. Of course, \a buf is a pointer to the chunk of data which
  57          * should be sent, and \a len is the length of this buffer.
  58          */
  59         void (*send)(long unsigned current_chunk, long unsigned chunks_sent,
  60                 const char *buf, size_t len, const char *header_buf,
  61                 size_t header_len);
  62         /**
  63          * Add file descriptors to fd_sets.
  64          *
  65          * The pre_select function of each supported sender is called just before
  66          * para_server enters its main select loop. Each sender may add its own
  67          * file descriptors to the \a rfds or the \a wfds set.
  68          *
  69          * If a file descriptor was added, \a max_fileno must be increased by
  70          * this function, if necessary.
  71          *
  72          * \sa select(2).
  73          */
  74         void (*pre_select)(int *max_fileno, fd_set *rfds, fd_set *wfds);
  75         /**
  76          * Handle the file descriptors which are ready for I/O.
  77          *
  78          * If the pre_select hook added one ore more file descriptors to the
  79          * read or write set, this is the hook to check the result and do any
  80          * I/O on those descriptors which are ready for reading/writing.
  81          */
  82         void (*post_select)(fd_set *rfds, fd_set *wfds);
  83         /**
  84          * Terminate all connected clients.
  85          *
  86          * This is called e.g. if the stop command was executed. It should make
  87          * the clients aware of the end-of-file condition.
  88          */
  89         void (*shutdown_clients)(void);
  90         /**
  91          * Array of function pointers for the sender subcommands.
  92          *
  93          * Each sender may implement any subset of the sender commands by
  94          * filling in the appropriate function pointer in the array. A \p NULL
  95          * pointer means this command is not implemented by this sender.
  96          */
  97         int (*client_cmds[NUM_SENDER_CMDS])(struct sender_command_data*);
  98         /**
  99          * Resolve target-specific URL string
 100          *
 101          * This method must be defined if the sender supports the add/delete
 102          * subcommands. It interprets a string specifying a target URL in a
 103          * sender-specific fashion (e.g. embedded FEC string). It can also
 104          * fill in sender-specific defaults if necessary.
 105          */
 106         int (*resolve_target)(const char *, struct sender_command_data *);
 107 };
 108
 109 /** Describes one client, connected to a paraslash sender. */
 110 struct sender_client {
 111         /** The file descriptor of the client. */
 112         int fd;
 113         /** The socket "name" of the client. */
 114         char *name;
 115         /** The position of this client in the client list. */
 116         struct list_head node;
 117         /** Non-zero if audio file header has been sent. */
 118         int header_sent;
 119         /** The list of pending chunks for this client. */
 120         struct chunk_queue *cq;
 121         /** Data specific to the particular sender. */
 122         void *private_data;
 123 };
 124
 125 /**
 126  * Each paraslash sender may register arbitrary many clients to the virtual
 127  * streaming system, possibly with varying fec parameters. In order to do so,
 128  * it must allocate a \a fec_client_parms structure and pass it to \ref
 129  * vss_add_fec_client.
 130  *
 131  * Clients are automatically removed from that list by the vss if an error
 132  * occurs, or if the sender requests deletion of a client by calling \ref
 133  * vss_del_fec_client().
 134  */
 135
 136 /** FEC parameters requested by FEC clients. */
 137 struct fec_client_parms {
 138         /** Number of data slices plus redundant slices. */
 139         uint8_t slices_per_group;
 140         /** Number of slices minus number of redundant slices. */
 141         uint8_t data_slices_per_group;
 142         /** Whether the header must be sent periodically. */
 143         bool need_periodic_header;
 144         /**
 145          * Transport-layer initialisation for FEC support.
 146          *
 147          * This optional function serves (a) to make the transport layer
 148          * ready to send FEC slices and (b) to determine the Maximum
 149          * Packet Size (MPS) supported by the connection. The MPS value
 150          * determines the largest payload size. This value is used to
 151          * send FEC slices that are not larger than the path MTU, to avoid
 152          * fragmentation and to maximize packet utilization. The user can
 153          * alternatively specify a slice size of up to this value.
 154          */
 155         int (*init_fec)(struct sender_client *sc);
 156         /** Push out FEC-encoded packets */
 157         void (*send_fec)(struct sender_client *sc, char *buf, size_t len);
 158 };
 159
 160 /** Describes the current status of one paraslash sender. */
 161 struct sender_status {
 162         /** The file descriptor of the socket this sender is listening on. */
 163         int listen_fd;
 164         /** The TCP/DCCP port used by this sender. */
 165         int port;
 166         /** The current number of simultaneous connections. */
 167         int num_clients;
 168         /** The maximal number of simultaneous connections. */
 169         int max_clients;
 170         /** Whether the access control list is a whitelist. */
 171         int default_deny;
 172         /** The whitelist/blacklist. */
 173         struct list_head acl;
 174         /** The list of connected clients. */
 175         struct list_head client_list;
 176 };
 177
 178 void shutdown_client(struct sender_client *sc, struct sender_status *ss);
 179 void shutdown_clients(struct sender_status *ss);
 180 void init_sender_status(struct sender_status *ss, char **access_arg, int num_access_args,
 181         int port, int max_clients, int default_deny);
 182 char *generic_sender_status(struct sender_status *ss, const char *name);
 183
 184 void generic_com_allow(struct sender_command_data *scd,
 185                 struct sender_status *ss);
 186 void generic_com_deny(struct sender_command_data *scd,
 187                 struct sender_status *ss);
 188 int generic_com_on(struct sender_status *ss, unsigned protocol);
 189 void generic_com_off(struct sender_status *ss);
 190 char *generic_sender_help(void);
 191 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds);
 192 int send_queued_chunks(int fd, struct chunk_queue *cq);
 193 int parse_fec_url(const char *arg, struct sender_command_data *scd);