send.h

   1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file send.h Sender-related defines and structures. */
   4
   5 /**
   6  * A little preprocessor fu helps to create the sender_subcommand enumeration
   7  * below and the list of sender name strings without duplicating the commands.
   8  */
   9 #define SENDER_SUBCOMMANDS \
  10         SENDER_SUBCOMMAND(add) /**< Add a target (udp only). */ \
  11         SENDER_SUBCOMMAND(delete) /**< Delete a target (udp only). */ \
  12         SENDER_SUBCOMMAND(allow) /**< Allow connections from given IP address(es). */ \
  13         SENDER_SUBCOMMAND(deny) /**< Deny connections from given IP address(es). */ \
  14         SENDER_SUBCOMMAND(on) /**< Activate the sender. */ \
  15         SENDER_SUBCOMMAND(off) /**< Deactivate the sender. */ \
  16
  17 /** Concatenate "SENDER_" and the given arg and append a comma. */
  18 #define SENDER_SUBCOMMAND(_name) SENDER_ ## _name,
  19
  20 /**
  21  * Each sender subcommand gets an SENDER_xxx identifier. The identifier is
  22  * passed from the sender command handler to the server process via shared
  23  * memory.
  24  */
  25 enum sender_subcommand {
  26         SENDER_SUBCOMMANDS /**< List of SENDER_xxx identifiers. */
  27         NUM_SENDER_CMDS /**< Used as array size in struct \ref sender. */
  28 };
  29
  30 #undef SENDER_SUBCOMMAND
  31
  32 /**
  33  * Redefine it to expand to the stringified name of the sender so that
  34  * SENDER_SUBCOMMANDS above now expands to the comma-separated list of sender
  35  * name strings. This is used in command.c to define and initialize an array of
  36  * char pointers.
  37  */
  38 #define SENDER_SUBCOMMAND(_name) #_name,
  39
  40 /**
  41  * Describes one supported sender of para_server.
  42  *
  43  * \sa \ref http_send.c \ref udp_send.c, \ref dccp_send.c.
  44  */
  45 struct sender {
  46         /** The name of the sender. */
  47         const char *name;
  48         /**
  49          * Parse the command line options and initialize this sender (e.g.,
  50          * initialize target or access control lists, listen on a network
  51          * socket, etc.).
  52          */
  53         void (*init)(void);
  54         /**
  55          * Return the help text of this sender.
  56          *
  57          * The result must be dynamically allocated and is freed by the caller.
  58          */
  59         char* (*help)(void);
  60         /**
  61          * Return current status info about this sender.
  62          *
  63          * The result must be dynamically allocated and is freed by the caller.
  64          */
  65         char* (*status)(void);
  66         /**
  67          * The send-hook.
  68          *
  69          * It gets called whenever para_server is playing and the current
  70          * audio format handler indicates that another chunk of data should
  71          * be sent now. The two parameters \a current_chunk and \a chunks_sent
  72          * only differ if the stream was repositioned by the \a ff or \a jmp
  73          * command. Of course, \a buf is a pointer to the chunk of data which
  74          * should be sent, and \a len is the length of this buffer.
  75          */
  76         void (*send)(long unsigned current_chunk, long unsigned chunks_sent,
  77                 const char *buf, size_t len, const char *header_buf,
  78                 size_t header_len);
  79         /**
  80          * Add file descriptors to fd_sets.
  81          *
  82          * The pre_select function of each supported sender is called just before
  83          * para_server enters its main select loop. Each sender may add its own
  84          * file descriptors to the \a rfds or the \a wfds set.
  85          *
  86          * If a file descriptor was added, \a max_fileno must be increased by
  87          * this function, if necessary.
  88          *
  89          * \sa select(2).
  90          */
  91         void (*pre_select)(int *max_fileno, fd_set *rfds, fd_set *wfds);
  92         /**
  93          * Handle the file descriptors which are ready for I/O.
  94          *
  95          * If the pre_select hook added one ore more file descriptors to the
  96          * read or write set, this is the hook to check the result and do any
  97          * I/O on those descriptors which are ready for reading/writing.
  98          */
  99         void (*post_select)(fd_set *rfds, fd_set *wfds);
 100         /**
 101          * Terminate all connected clients.
 102          *
 103          * This is called e.g. if the stop command was executed. It should make
 104          * the clients aware of the end-of-file condition.
 105          */
 106         void (*shutdown_clients)(void);
 107         /** Dellocate all resources. Only called on exit. */
 108         void (*shutdown)(void);
 109         /**
 110          * Array of function pointers for the sender subcommands.
 111          *
 112          * Each sender may implement any subset of the sender commands by
 113          * filling in the appropriate function pointer in the array. A \p NULL
 114          * pointer means this command is not implemented by this sender.
 115          */
 116         int (*client_cmds[NUM_SENDER_CMDS])(struct sender_command_data*);
 117         /**
 118          * Resolve target-specific URL string
 119          *
 120          * This method must be defined if the sender supports the add/delete
 121          * subcommands. It interprets a string specifying a target URL in a
 122          * sender-specific fashion (e.g. embedded FEC string). It can also
 123          * fill in sender-specific defaults if necessary.
 124          */
 125         int (*resolve_target)(const char *, struct sender_command_data *);
 126 };
 127
 128 /** NULL-terminated list, defined in \ref vss.c. */
 129 extern const struct sender * const senders[];
 130 /** Iterate over all senders. */
 131 #define FOR_EACH_SENDER(_i) for ((_i) = 0; senders[(_i)]; (_i)++)
 132
 133 /** Describes one client, connected to a paraslash sender. */
 134 struct sender_client {
 135         /** The file descriptor of the client. */
 136         int fd;
 137         /** The socket "name" of the client. */
 138         char *name;
 139         /** The position of this client in the client list. */
 140         struct list_head node;
 141         /** Non-zero if audio file header has been sent. */
 142         int header_sent;
 143         /** The list of pending chunks for this client. */
 144         struct chunk_queue *cq;
 145         /** Data specific to the particular sender. */
 146         void *private_data;
 147 };
 148
 149 /**
 150  * Each paraslash sender may register arbitrary many clients to the virtual
 151  * streaming system, possibly with varying fec parameters. In order to do so,
 152  * it must allocate a \a fec_client_parms structure and pass it to \ref
 153  * vss_add_fec_client.
 154  *
 155  * Clients are automatically removed from that list by the vss if an error
 156  * occurs, or if the sender requests deletion of a client by calling \ref
 157  * vss_del_fec_client().
 158  */
 159
 160 /** FEC parameters requested by FEC clients. */
 161 struct fec_client_parms {
 162         /** Number of data slices plus redundant slices. */
 163         uint8_t slices_per_group;
 164         /** Number of slices minus number of redundant slices. */
 165         uint8_t data_slices_per_group;
 166         /** Whether the header must be sent periodically. */
 167         bool need_periodic_header;
 168         /**
 169          * Transport-layer initialisation for FEC support.
 170          *
 171          * This optional function serves (a) to make the transport layer
 172          * ready to send FEC slices and (b) to determine the Maximum
 173          * Packet Size (MPS) supported by the connection. The MPS value
 174          * determines the largest payload size. This value is used to
 175          * send FEC slices that are not larger than the path MTU, to avoid
 176          * fragmentation and to maximize packet utilization. The user can
 177          * alternatively specify a slice size of up to this value.
 178          */
 179         int (*init_fec)(struct sender_client *sc);
 180         /** Push out FEC-encoded packets */
 181         void (*send_fec)(struct sender_client *sc, char *buf, size_t len);
 182 };
 183
 184 /** Describes the current status of one paraslash sender. */
 185 struct sender_status {
 186         /** Number of sockets to listen on, size of the two arrays below. */
 187         unsigned num_listen_fds;
 188         /** Derived from --http-listen-address and --dccp-listen-address. */
 189         char **listen_addresses;
 190         /** Default TCP/DCCP port number for addresses w/o port. */
 191         int default_port;
 192         /** The socket fd(s) this sender is listening on. */
 193         int *listen_fds;
 194         /** The current number of simultaneous connections. */
 195         int num_clients;
 196         /** The maximal number of simultaneous connections. */
 197         int max_clients;
 198         /** Whether the access control list is a whitelist. */
 199         int default_deny;
 200         /** The whitelist/blacklist. */
 201         struct list_head acl;
 202         /** The list of connected clients. */
 203         struct list_head client_list;
 204 };
 205
 206 /** Iterate over all listening addresses of the http/dccp sender. */
 207 #define FOR_EACH_LISTEN_FD(_n, _ss) for (_n = 0; _n < (_ss)->num_listen_fds; _n++)
 208
 209 void shutdown_client(struct sender_client *sc, struct sender_status *ss);
 210 void shutdown_clients(struct sender_status *ss);
 211 void init_sender_status(struct sender_status *ss,
 212                 const struct lls_opt_result *acl_opt_result,
 213                 const struct lls_opt_result *listen_address_opt_result,
 214                 int default_port, int max_clients, int default_deny);
 215 void free_sender_status(const struct sender_status *ss);
 216 char *generic_sender_status(struct sender_status *ss, const char *name);
 217 void generic_com_allow(struct sender_command_data *scd,
 218                 struct sender_status *ss);
 219 void generic_com_deny(struct sender_command_data *scd,
 220                 struct sender_status *ss);
 221 void generic_com_on(struct sender_status *ss, unsigned protocol);
 222 void generic_acl_deplete(struct list_head *acl);
 223 void generic_com_off(struct sender_status *ss);
 224 char *generic_sender_help(void);
 225 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds);
 226 int send_queued_chunks(int fd, struct chunk_queue *cq);
 227 int parse_fec_url(const char *arg, struct sender_command_data *scd);