source: dcc.h @ cc0ad0a

/********************************************************************\
* BitlBee -- An IRC to other IM-networks gateway                     *
*                                                                    *
* Copyright 2006 Marijn Kruisselbrink and others                     *
* Copyright 2007 Uli Meis <a.sporto+bee@gmail.com>                   *
\********************************************************************/

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

/*
 * DCC SEND
 *
 * Historically, DCC means send 1024 Bytes and wait for a 4 byte reply
 * acknowledging all transferred data. This is ridiculous for two reasons.  The
 * first being that TCP is a stream oriented protocol that doesn't care much
 * about your idea of a packet. The second reason being that TCP is a reliable
 * transfer protocol with its own sophisticated ACK mechanism, making DCCs ACK
 * mechanism look like a joke. For these reasons, DCCs requirements have
 * (hopefully) been relaxed in most implementations and this implementation
 * depends upon at least the following: The 1024 bytes need not be transferred
 * at once, i.e. packets can be smaller. A second relaxation has apparently
 * gotten the name "DCC SEND ahead" which basically means to not give a damn
 * about those DCC ACKs and just send data as you please. This behaviour is
 * enabled by default. Note that this also means that packets may be as large
 * as the maximum segment size.
 */

#ifndef _DCC_H
#define _DCC_H

/* Send an ACK after receiving this amount of data */
#define DCC_PACKET_SIZE 1024

/* Time in seconds that a DCC transfer can be stalled before being aborted.
 * By handling this here individual protocols don't have to think about this. */
#define DCC_MAX_STALL 120

typedef struct dcc_file_transfer {

        struct im_connection *ic;

        /*
         * Depending in the status of the file transfer, this is either the socket that is
         * being listened on for connections, or the socket over which the file transfer is
         * taking place.
         */
        int fd;

        /*
         * IDs returned by b_input_add for watch_ing over the above socket.
         */
        gint watch_in;   /* readable */
        gint watch_out;  /* writable */

        /* the progress watcher cancels any file transfer if nothing happens within DCC_MAX_STALL */
        gint progress_timeout;
        size_t progress_bytes_last;

        /*
         * The total amount of bytes that have been sent to the irc client.
         */
        size_t bytes_sent;

        /*
         * Handle the wonderful sadly-not-deprecated ACKs.
         */
        guint32 acked;
        int acked_len;

        /* imc's handle */
        file_transfer_t *ft;

        /* if we're receiving, this is the sender's socket address */
        struct sockaddr_storage saddr;

        /* set to true if the protocol has finished
         * (i.e. called imcb_file_finished)
         */
        int proto_finished;
} dcc_file_transfer_t;

file_transfer_t *dccs_send_start(struct im_connection *ic, irc_user_t *iu, const char *file_name, size_t file_size);
void dcc_canceled(file_transfer_t *file, char *reason);
gboolean dccs_send_write(file_transfer_t *file, char *data, unsigned int data_size);
file_transfer_t *dcc_request(struct im_connection *ic, char* const* ctcp);
void dcc_finish(file_transfer_t *file);
void dcc_close(file_transfer_t *file);
gboolean dccs_recv_start(file_transfer_t *ft);

#endif