peermux.c File Reference

Peer Content Caching and Retrieval (PeerDist) protocol multiplexer. More...

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ipxe/uri.h>
#include <ipxe/xferbuf.h>
#include <ipxe/job.h>
#include <ipxe/peerblk.h>
#include <ipxe/peermux.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static void	peermux_free (struct refcnt *refcnt)
	Free PeerDist download multiplexer. More...
static void	peermux_close (struct peerdist_multiplexer *peermux, int rc)
	Close PeerDist download multiplexer. More...
static int	peermux_progress (struct peerdist_multiplexer *peermux, struct job_progress *progress)
	Report progress of PeerDist download. More...
static int	peermux_info_deliver (struct peerdist_multiplexer *peermux, struct io_buffer *iobuf, struct xfer_metadata *meta)
	Receive content information. More...
static void	peermux_info_close (struct peerdist_multiplexer *peermux, int rc)
	Close content information interface. More...
static void	peermux_step (struct peerdist_multiplexer *peermux)
	Initiate multiplexed block download. More...
static int	peermux_block_deliver (struct peerdist_multiplexed_block *peermblk, struct io_buffer *iobuf, struct xfer_metadata *meta)
	Receive data from multiplexed block download. More...
static struct xfer_buffer *	peermux_block_buffer (struct peerdist_multiplexed_block *peermblk)
	Get multiplexed block download underlying data transfer buffer. More...
static void	peermux_block_stat (struct peerdist_multiplexed_block *peermblk, struct peerdisc_peer *peer, struct list_head *peers)
	Record peer discovery statistics. More...
static void	peermux_block_close (struct peerdist_multiplexed_block *peermblk, int rc)
	Close multiplexed block download. More...
int	peermux_filter (struct interface *xfer, struct interface *info, struct uri *uri)
	Add PeerDist content-encoding filter. More...

Variables
static struct interface_operation	peermux_xfer_operations []
	Data transfer interface operations. More...
static struct interface_descriptor	peermux_xfer_desc
	Data transfer interface descriptor. More...
static struct interface_operation	peermux_info_operations []
	Content information interface operations. More...
static struct interface_descriptor	peermux_info_desc
	Content information interface descriptor. More...
static struct interface_operation	peermux_block_operations []
	Block download data transfer interface operations. More...
static struct interface_descriptor	peermux_block_desc
	Block download data transfer interface descriptor. More...
static struct process_descriptor	peermux_process_desc
	Block download initiation process descriptor. More...

Detailed Description

Peer Content Caching and Retrieval (PeerDist) protocol multiplexer.

Definition in file peermux.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

peermux_free()

static void peermux_free ( struct refcnt *  refcnt )

static

Free PeerDist download multiplexer.

Parameters

refcnt

Reference count

Definition at line 47 of file peermux.c.

                                                   {
        struct peerdist_multiplexer *peermux =
                container_of ( refcnt, struct peerdist_multiplexer, refcnt );

        uri_put ( peermux->uri );
        xferbuf_free ( &peermux->buffer );
        free ( peermux );
}

References peerdist_multiplexer::buffer, container_of, free, peerdist_multiplexer::uri, uri_put(), and xferbuf_free().

Referenced by peermux_filter().

peermux_close()

static void peermux_close ( struct peerdist_multiplexer *  peermux, int  rc  )

static

Close PeerDist download multiplexer.

Parameters

peermux	PeerDist download multiplexer
rc	Reason for close

Definition at line 62 of file peermux.c.

                                                                           {
        unsigned int i;

        /* Stop block download initiation process */
        process_del ( &peermux->process );

        /* Shut down all block downloads */
        for ( i = 0 ; i < PEERMUX_MAX_BLOCKS ; i++ )
                intf_shutdown ( &peermux->block[i].xfer, rc );

        /* Shut down all other interfaces (which may be connected to
         * the same object).
         */
        intf_nullify ( &peermux->info ); /* avoid potential loops */
        intf_shutdown ( &peermux->xfer, rc );
        intf_shutdown ( &peermux->info, rc );
}

References peerdist_multiplexer::block, peerdist_multiplexer::info, intf_nullify(), intf_shutdown(), PEERMUX_MAX_BLOCKS, peerdist_multiplexer::process, process_del(), rc, peerdist_multiplexed_block::xfer, and peerdist_multiplexer::xfer.

Referenced by peermux_block_close(), peermux_info_close(), peermux_info_deliver(), and peermux_step().

peermux_progress()

static int peermux_progress ( struct peerdist_multiplexer *  peermux, struct job_progress *  progress  )

static

Report progress of PeerDist download.

Parameters

peermux	PeerDist download multiplexer
progress	Progress report to fill in

Return values

ongoing_rc

Ongoing job status code (if known)

Definition at line 87 of file peermux.c.

                                                              {
        struct peerdist_statistics *stats = &peermux->stats;
        unsigned int percentage;

        /* Construct PeerDist status message */
        if ( stats->total ) {
                percentage = ( ( 100 * stats->local ) / stats->total );
                snprintf ( progress->message, sizeof ( progress->message ),
                           "%3d%% from %d peers", percentage, stats->peers );
        }

        return 0;
}

References peerdist_statistics::local, job_progress::message, peerdist_statistics::peers, snprintf(), peerdist_multiplexer::stats, and peerdist_statistics::total.

peermux_info_deliver()

static int peermux_info_deliver ( struct peerdist_multiplexer *  peermux, struct io_buffer *  iobuf, struct xfer_metadata *  meta  )

static

Receive content information.

Parameters

peermux	PeerDist download multiplexer
iobuf	I/O buffer
meta	Data transfer metadata

Return values

rc	Return status code

Definition at line 110 of file peermux.c.

                                                               {
        int rc;

        /* Add data to buffer */
        if ( ( rc = xferbuf_deliver ( &peermux->buffer, iobuf, meta ) ) != 0 )
                goto err;

        return 0;

 err:
        peermux_close ( peermux, rc );
        return rc;
}

References peerdist_multiplexer::buffer, meta, peermux_close(), rc, and xferbuf_deliver().

peermux_info_close()

static void peermux_info_close ( struct peerdist_multiplexer *  peermux, int  rc  )

static

Close content information interface.

Parameters

peermux	PeerDist download multiplexer
rc	Reason for close

Definition at line 132 of file peermux.c.

                                                                               {
        struct xfer_buffer *buffer = &peermux->buffer;
        struct peerdist_info *info = &peermux->cache.info;
        size_t len;

        /* Terminate download on error */
        if ( rc != 0 )
                goto err;

        /* Successfully closing the content information interface
         * indicates that the content information has been fully
         * received, and initiates the actual PeerDist download.
         */

        /* Shut down content information interface */
        intf_shutdown ( &peermux->info, rc );

        /* Parse content information */
        if ( ( rc = peerdist_info ( buffer->data, buffer->len, info ) ) != 0 ) {
                DBGC ( peermux, "PEERMUX %p could not parse content info: %s\n",
                       peermux, strerror ( rc ) );
                goto err;
        }

        /* Notify recipient of total download size */
        len = ( info->trim.end - info->trim.start );
        if ( ( rc = xfer_seek ( &peermux->xfer, len ) ) != 0 ) {
                DBGC ( peermux, "PEERMUX %p could not presize buffer: %s\n",
                       peermux, strerror ( rc ) );
                goto err;
        }
        xfer_seek ( &peermux->xfer, 0 );

        /* Start block download process */
        process_add ( &peermux->process );

        return;

 err:
        peermux_close ( peermux, rc );
}

References buffer, peerdist_multiplexer::buffer, peerdist_multiplexer::cache, DBGC, peerdist_multiplexer::info, info, peerdist_info_cache::info, intf_shutdown(), len, peermux_close(), peerdist_multiplexer::process, process_add(), rc, strerror(), peerdist_multiplexer::xfer, and xfer_seek().

peermux_step()

static void peermux_step ( struct peerdist_multiplexer *  peermux )

static

Initiate multiplexed block download.

Parameters

peermux

PeerDist download multiplexer

Definition at line 179 of file peermux.c.

                                                                  {
        struct peerdist_info *info = &peermux->cache.info;
        struct peerdist_info_segment *segment = &peermux->cache.segment;
        struct peerdist_info_block *block = &peermux->cache.block;
        struct peerdist_multiplexed_block *peermblk;
        unsigned int next_segment;
        unsigned int next_block;
        int rc;

        /* Stop initiation process if all block downloads are busy */
        peermblk = list_first_entry ( &peermux->idle,
                                      struct peerdist_multiplexed_block, list );
        if ( ! peermblk ) {
                process_del ( &peermux->process );
                return;
        }

        /* Increment block index */
        next_block = ( block->index + 1 );

        /* Move to first/next segment, if applicable */
        if ( next_block >= segment->blocks ) {

                /* Reset block index */
                next_block = 0;

                /* Calculate segment index */
                next_segment = ( segment->info ? ( segment->index + 1 ) : 0 );

                /* If we have finished all segments and have no
                 * remaining block downloads, then we are finished.
                 */
                if ( next_segment >= info->segments ) {
                        process_del ( &peermux->process );
                        if ( list_empty ( &peermux->busy ) )
                                peermux_close ( peermux, 0 );
                        return;
                }

                /* Get content information segment */
                if ( ( rc = peerdist_info_segment ( info, segment,
                                                    next_segment ) ) != 0 ) {
                        DBGC ( peermux, "PEERMUX %p could not get segment %d "
                               "information: %s\n", peermux, next_segment,
                               strerror ( rc ) );
                        goto err;
                }
        }

        /* Get content information block */
        if ( ( rc = peerdist_info_block ( segment, block, next_block ) ) != 0 ){
                DBGC ( peermux, "PEERMUX %p could not get segment %d block "
                       "%d information: %s\n", peermux, segment->index,
                       next_block, strerror ( rc ) );
                goto err;
        }

        /* Ignore block if it lies entirely outside the trimmed range */
        if ( block->trim.start == block->trim.end ) {
                DBGC ( peermux, "PEERMUX %p skipping segment %d block %d\n",
                       peermux, segment->index, block->index );
                return;
        }

        /* Start downloading this block */
        if ( ( rc = peerblk_open ( &peermblk->xfer, peermux->uri,
                                   block ) ) != 0 ) {
                DBGC ( peermux, "PEERMUX %p could not start download for "
                       "segment %d block %d: %s\n", peermux, segment->index,
                       block->index, strerror ( rc ) );
                goto err;
        }

        /* Move to list of busy block downloads */
        list_del ( &peermblk->list );
        list_add_tail ( &peermblk->list, &peermux->busy );

        return;

 err:
        peermux_close ( peermux, rc );
}

References block, peerdist_info_cache::block, peerdist_multiplexer::busy, peerdist_multiplexer::cache, DBGC, peerdist_multiplexer::idle, info, peerdist_info_cache::info, peerdist_multiplexed_block::list, list_add_tail, list_del, list_empty, list_first_entry, peerblk_open(), peerdist_multiplexed_block::peermux, peermux_close(), peerdist_multiplexer::process, process_del(), rc, peerdist_info_cache::segment, segment, strerror(), peerdist_multiplexer::uri, and peerdist_multiplexed_block::xfer.

peermux_block_deliver()

static int peermux_block_deliver ( struct peerdist_multiplexed_block *  peermblk, struct io_buffer *  iobuf, struct xfer_metadata *  meta  )

static

Receive data from multiplexed block download.

Parameters

peermblk	PeerDist multiplexed block download
iobuf	I/O buffer
meta	Data transfer metadata

Return values

rc	Return status code

Definition at line 270 of file peermux.c.

                                                                {
        struct peerdist_multiplexer *peermux = peermblk->peermux;

        /* Sanity check: all block downloads must use absolute
         * positions for all deliveries, since they run concurrently.
         */
        assert ( meta->flags & XFER_FL_ABS_OFFSET );

        /* We can't use a simple passthrough interface descriptor,
         * since there are multiple block download interfaces.
         */
        return xfer_deliver ( &peermux->xfer, iob_disown ( iobuf ), meta );
}

References assert(), iob_disown, meta, peerdist_multiplexed_block::peermux, peerdist_multiplexer::xfer, xfer_deliver(), and XFER_FL_ABS_OFFSET.

peermux_block_buffer()

static struct xfer_buffer* peermux_block_buffer ( struct peerdist_multiplexed_block *  peermblk )

static

Get multiplexed block download underlying data transfer buffer.

Parameters

peermblk

PeerDist multiplexed download block

Return values

xferbuf

Data transfer buffer, or NULL on error

Definition at line 293 of file peermux.c.

                                                                     {
        struct peerdist_multiplexer *peermux = peermblk->peermux;

        /* We can't use a simple passthrough interface descriptor,
         * since there are multiple block download interfaces.
         */
        return xfer_buffer ( &peermux->xfer );
}

References peerdist_multiplexed_block::peermux, peerdist_multiplexer::xfer, and xfer_buffer().

peermux_block_stat()

static void peermux_block_stat ( struct peerdist_multiplexed_block *  peermblk, struct peerdisc_peer *  peer, struct list_head *  peers  )

static

Record peer discovery statistics.

Parameters

peermblk	PeerDist multiplexed block download
peer	Selected peer (or NULL)
peers	List of available peers

Definition at line 309 of file peermux.c.

                                                           {
        struct peerdist_multiplexer *peermux = peermblk->peermux;
        struct peerdist_statistics *stats = &peermux->stats;
        struct peerdisc_peer *tmp;
        unsigned int count = 0;

        /* Record maximum number of available peers */
        list_for_each_entry ( tmp, peers, list )
                count++;
        if ( count > stats->peers )
                stats->peers = count;

        /* Update block counts */
        if ( peer )
                stats->local++;
        stats->total++;
        DBGC2 ( peermux, "PEERMUX %p downloaded %d/%d from %d peers\n",
                peermux, stats->local, stats->total, stats->peers );
}

References count, DBGC2, peerdisc_peer::list, list_for_each_entry, peerdist_statistics::local, peer, peerdist_multiplexed_block::peermux, peerdist_statistics::peers, peerdist_multiplexer::stats, tmp, and peerdist_statistics::total.

peermux_block_close()

static void peermux_block_close ( struct peerdist_multiplexed_block *  peermblk, int  rc  )

static

Close multiplexed block download.

Parameters

peermblk	PeerDist multiplexed block download
rc	Reason for close

Definition at line 337 of file peermux.c.

                                           {
        struct peerdist_multiplexer *peermux = peermblk->peermux;

        /* Move to list of idle downloads */
        list_del ( &peermblk->list );
        list_add_tail ( &peermblk->list, &peermux->idle );

        /* If any error occurred, terminate the whole multiplexer */
        if ( rc != 0 ) {
                peermux_close ( peermux, rc );
                return;
        }

        /* Restart data transfer interface */
        intf_restart ( &peermblk->xfer, rc );

        /* Restart block download initiation process */
        process_add ( &peermux->process );
}

References peerdist_multiplexer::idle, intf_restart(), peerdist_multiplexed_block::list, list_add_tail, list_del, peerdist_multiplexed_block::peermux, peermux_close(), peerdist_multiplexer::process, process_add(), rc, and peerdist_multiplexed_block::xfer.

peermux_filter()

int peermux_filter	(	struct interface *	xfer,
		struct interface *	info,
		struct uri *	uri
	)

Add PeerDist content-encoding filter.

Parameters

xfer	Data transfer interface
info	Content information interface
uri	Original URI

Return values

rc	Return status code

Definition at line 412 of file peermux.c.

                                       {
        struct peerdist_multiplexer *peermux;
        struct peerdist_multiplexed_block *peermblk;
        unsigned int i;

        /* Allocate and initialise structure */
        peermux = zalloc ( sizeof ( *peermux ) );
        if ( ! peermux )
                return -ENOMEM;
        ref_init ( &peermux->refcnt, peermux_free );
        intf_init ( &peermux->xfer, &peermux_xfer_desc, &peermux->refcnt );
        intf_init ( &peermux->info, &peermux_info_desc, &peermux->refcnt );
        peermux->uri = uri_get ( uri );
        xferbuf_umalloc_init ( &peermux->buffer );
        process_init_stopped ( &peermux->process, &peermux_process_desc,
                               &peermux->refcnt );
        INIT_LIST_HEAD ( &peermux->busy );
        INIT_LIST_HEAD ( &peermux->idle );
        for ( i = 0 ; i < PEERMUX_MAX_BLOCKS ; i++ ) {
                peermblk = &peermux->block[i];
                peermblk->peermux = peermux;
                list_add_tail ( &peermblk->list, &peermux->idle );
                intf_init ( &peermblk->xfer, &peermux_block_desc,
                            &peermux->refcnt );
        }

        /* Attach to parent interfaces, mortalise self, and return */
        intf_plug_plug ( &peermux->xfer, xfer );
        intf_plug_plug ( &peermux->info, info );
        ref_put ( &peermux->refcnt );
        return 0;
}

References peerdist_multiplexer::block, peerdist_multiplexer::buffer, peerdist_multiplexer::busy, ENOMEM, peerdist_multiplexer::idle, peerdist_multiplexer::info, info, INIT_LIST_HEAD, intf_init(), intf_plug_plug(), peerdist_multiplexed_block::list, list_add_tail, peerdist_multiplexed_block::peermux, peermux_block_desc, peermux_free(), peermux_info_desc, PEERMUX_MAX_BLOCKS, peermux_process_desc, peermux_xfer_desc, peerdist_multiplexer::process, process_init_stopped(), ref_init, ref_put, peerdist_multiplexer::refcnt, peerdist_multiplexer::uri, uri_get(), peerdist_multiplexed_block::xfer, peerdist_multiplexer::xfer, xferbuf_umalloc_init(), and zalloc().

Referenced by http_peerdist_init().

Variable Documentation

peermux_xfer_operations

struct interface_operation peermux_xfer_operations[]

static

Initial value:

= {
        INTF_OP ( job_progress, struct peerdist_multiplexer *,
                  peermux_progress ),
        INTF_OP ( intf_close, struct peerdist_multiplexer *, peermux_close ),
}

Data transfer interface operations.

Definition at line 359 of file peermux.c.

peermux_xfer_desc

struct interface_descriptor peermux_xfer_desc

static

Initial value:

=
        INTF_DESC_PASSTHRU ( struct peerdist_multiplexer, xfer,
                             peermux_xfer_operations, info )

Data transfer interface descriptor.

Definition at line 366 of file peermux.c.

Referenced by peermux_filter().

peermux_info_operations

struct interface_operation peermux_info_operations[]

static

Initial value:

= {
        INTF_OP ( xfer_deliver, struct peerdist_multiplexer *,
                  peermux_info_deliver ),
        INTF_OP ( intf_close, struct peerdist_multiplexer *,
                  peermux_info_close ),
}

Content information interface operations.

Definition at line 371 of file peermux.c.

peermux_info_desc

struct interface_descriptor peermux_info_desc

static

Initial value:

=
        INTF_DESC_PASSTHRU ( struct peerdist_multiplexer, info,
                             peermux_info_operations, xfer )

Content information interface descriptor.

Definition at line 379 of file peermux.c.

Referenced by peermux_filter().

peermux_block_operations

struct interface_operation peermux_block_operations[]

static

Initial value:

= {
        INTF_OP ( xfer_deliver, struct peerdist_multiplexed_block *,
                  peermux_block_deliver ),
        INTF_OP ( xfer_buffer, struct peerdist_multiplexed_block *,
                  peermux_block_buffer ),
        INTF_OP ( peerdisc_stat, struct peerdist_multiplexed_block *,
                  peermux_block_stat ),
        INTF_OP ( intf_close, struct peerdist_multiplexed_block *,
                  peermux_block_close ),
}

Block download data transfer interface operations.

Definition at line 384 of file peermux.c.

peermux_block_desc

struct interface_descriptor peermux_block_desc

static

Initial value:

=
        INTF_DESC ( struct peerdist_multiplexed_block, xfer,
                    peermux_block_operations )

Block download data transfer interface descriptor.

Definition at line 396 of file peermux.c.

Referenced by peermux_filter().

peermux_process_desc

struct process_descriptor peermux_process_desc

static

Initial value:

=
        PROC_DESC ( struct peerdist_multiplexer, process, peermux_step )

Block download initiation process descriptor.

Definition at line 401 of file peermux.c.

Referenced by peermux_filter().