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doc: Update channel.c top comments from latest

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Signed-off-by: David Goulet <dgoulet@torproject.org>
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David Goulet 2017-11-22 15:34:51 -05:00
parent 04762be612
commit 428ee55e51
1 changed files with 22 additions and 11 deletions
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33
src/or/channel.c
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@ -5,9 +5,8 @@
* \file channel.c
*
* \brief OR/OP-to-OR channel abstraction layer. A channel's job is to
* transfer cells from Tor instance to Tor instance.
* Currently, there is only one implementation of the channel abstraction: in
* channeltls.c.
* transfer cells from Tor instance to Tor instance. Currently, there is only
* one implementation of the channel abstraction: in channeltls.c.
*
* Channels are a higher-level abstraction than or_connection_t: In general,
* any means that two Tor relays use to exchange cells, or any means that a
@ -24,16 +23,28 @@
* connection.
*
* Every channel implementation is responsible for being able to transmit
* cells that are added to it with channel_write_cell() and related functions,
* and to receive incoming cells with the channel_queue_cell() and related
* functions. See the channel_t documentation for more information.
* cells that are passed to it
*
* When new cells arrive on a channel, they are passed to cell handler
* functions, which can be set by channel_set_cell_handlers()
* functions. (Tor's cell handlers are in command.c.)
* For *inbound* cells, the entry point is: channel_process_cell(). It takes a
* cell and will pass it to the cell handler set by
* channel_set_cell_handlers(). Currently, this is passed back to the command
* subsystem which is command_process_cell().
*
* Tor flushes cells to channels from relay.c in
* channel_flush_from_first_active_circuit().
* NOTE: For now, the seperation between channels and specialized channels
* (like channeltls) is not that well defined. So the channeltls layer calls
* channel_process_cell() which originally comes from the connection subsytem.
* This should be hopefully be fixed with #23993.
*
* For *outbound* cells, the entry point is: channel_write_packed_cell().
* Only packed cells are dequeued from the circuit queue by the scheduler
* which uses channel_flush_from_first_active_circuit() to decide which cells
* to flush from which circuit on the channel. They are then passed down to
* the channel subsystem. This calls the low layer with the function pointer
* .write_packed_cell().
*
* Each specialized channel (currently only channeltls_t) MUST implement a
* series of function found in channel_t. See channel.h for more
* documentation.
**/
/*