peerdisc.h File Reference

Peer Content Caching and Retrieval (PeerDist) protocol peer discovery. More...

#include <stdint.h>
#include <ipxe/refcnt.h>
#include <ipxe/list.h>
#include <ipxe/tables.h>
#include <ipxe/retry.h>
#include <ipxe/socket.h>
#include <ipxe/interface.h>
#include <ipxe/pccrc.h>

Go to the source code of this file.

Data Structures
struct	peerdisc_socket
	A PeerDist discovery socket. More...
struct	peerdisc_segment
	A PeerDist discovery segment. More...
struct	peerdisc_peer
	A PeerDist discovery peer. More...
struct	peerdisc_client
	A PeerDist discovery client. More...
struct	peerdisc_client_operations
	PeerDist discovery client operations. More...

Macros
#define	PEERDISC_SOCKETS   __table ( struct peerdisc_socket, "peerdisc_sockets" )
	PeerDist discovery socket table. More...
#define	__peerdisc_socket   __table_entry ( PEERDISC_SOCKETS, 01 )
	Declare a PeerDist discovery socket. More...
#define	peerdisc_stat_TYPE(object_type)

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static void	peerdisc_init (struct peerdisc_client *peerdisc, struct peerdisc_client_operations *op)
	Initialise PeerDist discovery. More...
void	peerdisc_stat (struct interface *intf, struct peerdisc_peer *peer, struct list_head *peers)
	Report peer discovery statistics. More...
int	peerdisc_open (struct peerdisc_client *peerdisc, const void *id, size_t len)
	Open PeerDist discovery client. More...
void	peerdisc_close (struct peerdisc_client *peerdisc)
	Close PeerDist discovery client. More...

Variables
unsigned int	peerdisc_timeout_secs
	Recommended discovery timeout (in seconds) More...

Detailed Description

Peer Content Caching and Retrieval (PeerDist) protocol peer discovery.

Definition in file peerdisc.h.

Macro Definition Documentation

PEERDISC_SOCKETS

#define PEERDISC_SOCKETS   __table ( struct peerdisc_socket, "peerdisc_sockets" )

PeerDist discovery socket table.

Definition at line 36 of file peerdisc.h.

__peerdisc_socket

struct peerdisc_socket peerdisc_socket_ipv6 __peerdisc_socket   __table_entry ( PEERDISC_SOCKETS, 01 )

Declare a PeerDist discovery socket.

PeerDist discovery IPv6 socket.

Definition at line 39 of file peerdisc.h.

peerdisc_stat_TYPE

#define peerdisc_stat_TYPE

(

object_type

)

Value:

typeof ( void ( object_type, struct peerdisc_peer *peer,        \
                        struct list_head *peers ) )

Definition at line 114 of file peerdisc.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

peerdisc_init()

static void peerdisc_init ( struct peerdisc_client *  peerdisc, struct peerdisc_client_operations *  op  )

inlinestatic

Initialise PeerDist discovery.

Parameters

peerdisc	PeerDist discovery client
op	Discovery operations

Definition at line 104 of file peerdisc.h.

                                                        {

        peerdisc->op = op;
}

References peerdisc_client::op, and op.

Referenced by peerblk_open().

peerdisc_stat()

void peerdisc_stat	(	struct interface *	intf,
		struct peerdisc_peer *	peer,
		struct list_head *	peers
	)

Report peer discovery statistics.

Parameters

intf	Interface
peer	Selected peer (or NULL)
peers	List of available peers

Definition at line 100 of file peerdisc.c.

                                               {
        struct interface *dest;
        peerdisc_stat_TYPE ( void * ) *op =
                intf_get_dest_op ( intf, peerdisc_stat, &dest );
        void *object = intf_object ( dest );

        if ( op ) {
                op ( object, peer, peers );
        } else {
                /* Default is to do nothing */
        }

        intf_put ( dest );
}

References dest, interface::intf, intf_get_dest_op, intf_object(), intf_put(), op, peer, peerdisc_stat(), and peerdisc_stat_TYPE.

Referenced by peerblk_done(), and peerdisc_stat().

peerdisc_open()

int peerdisc_open	(	struct peerdisc_client *	peerdisc,
		const void *	id,
		size_t	len
	)

Open PeerDist discovery client.

Parameters

peerdisc	PeerDist discovery client
id	Segment ID
len	Length of segment ID

Return values

rc	Return status code

Definition at line 559 of file peerdisc.c.

                                 {
        struct peerdisc_segment *segment;
        char id_string[ base16_encoded_len ( len ) + 1 /* NUL */ ];
        char *id_chr;
        int rc;

        /* Construct ID string */
        base16_encode ( id, len, id_string, sizeof ( id_string ) );
        for ( id_chr = id_string ; *id_chr ; id_chr++ )
                *id_chr = toupper ( *id_chr );

        /* Sanity check */
        assert ( peerdisc->segment == NULL );

        /* Open socket if this is the first segment */
        if ( list_empty ( &peerdisc_segments ) &&
             ( ( rc = peerdisc_socket_open() ) != 0 ) )
                return rc;

        /* Find or create segment */
        if ( ! ( ( segment = peerdisc_find ( id_string ) ) ||
                 ( segment = peerdisc_create ( id_string ) ) ) )
                return -ENOMEM;

        /* Add to list of clients */
        ref_get ( &segment->refcnt );
        peerdisc->segment = segment;
        list_add_tail ( &peerdisc->list, &segment->clients );

        return 0;
}

References assert(), base16_encoded_len(), ENOMEM, id_string, len, peerdisc_client::list, list_add_tail, list_empty, NULL, peerdisc_create(), peerdisc_find(), peerdisc_socket_open(), rc, ref_get, peerdisc_client::segment, segment, and toupper().

Referenced by peerblk_open().

peerdisc_close()

void peerdisc_close

(

struct peerdisc_client *

peerdisc

)

Close PeerDist discovery client.

Parameters

peerdisc

PeerDist discovery client

Definition at line 597 of file peerdisc.c.

                                                         {
        struct peerdisc_segment *segment = peerdisc->segment;

        /* Ignore if discovery is already closed */
        if ( ! segment )
                return;

        /* If no peers were discovered, reduce the recommended
         * discovery timeout to minimise delays on future requests.
         */
        if ( list_empty ( &segment->peers ) && peerdisc_timeout_secs ) {
                peerdisc_timeout_secs--;
                DBGC ( segment, "PEERDISC %p reducing timeout to %d "
                       "seconds\n", peerdisc, peerdisc_timeout_secs );
        }

        /* Remove from list of clients */
        peerdisc->segment = NULL;
        list_del ( &peerdisc->list );
        ref_put ( &segment->refcnt );

        /* If this was the last clients, destroy the segment */
        if ( list_empty ( &segment->clients ) )
                peerdisc_destroy ( segment );

        /* If there are no more segments, close the socket */
        if ( list_empty ( &peerdisc_segments ) )
                peerdisc_socket_close ( 0 );
}

References DBGC, peerdisc_client::list, list_del, list_empty, NULL, peerdisc_destroy(), peerdisc_socket_close(), peerdisc_timeout_secs, ref_put, peerdisc_client::segment, and segment.

Referenced by peerblk_close().

Variable Documentation

peerdisc_timeout_secs

unsigned int peerdisc_timeout_secs

Recommended discovery timeout (in seconds)

We reduce the recommended discovery timeout whenever a segment fails to discover any peers, and restore the default value whenever a valid discovery reply is received. We continue to send discovery requests even if the recommended timeout is reduced to zero.

This strategy is intended to minimise discovery delays when no peers are available on the network, while allowing downloads to quickly switch back to using PeerDist acceleration if new peers become available.

Definition at line 74 of file peerdisc.c.

Referenced by peerblk_open(), peerdisc_close(), and peerdisc_socket_rx().