552 lines
15 KiB
C
552 lines
15 KiB
C
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/*
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* Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <errno.h>
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#include <assert.h>
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#include <ipxe/xfer.h>
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#include <ipxe/iobuf.h>
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#include <ipxe/open.h>
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#include <ipxe/tcpip.h>
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#include <ipxe/uuid.h>
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#include <ipxe/base16.h>
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#include <ipxe/netdevice.h>
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#include <ipxe/timer.h>
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#include <ipxe/fault.h>
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#include <ipxe/pccrd.h>
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#include <ipxe/peerdisc.h>
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/** @file
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*
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* Peer Content Caching and Retrieval (PeerDist) protocol peer discovery
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*
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*/
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/** List of discovery segments */
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static LIST_HEAD ( peerdisc_segments );
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/** Number of repeated discovery attempts */
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#define PEERDISC_REPEAT_COUNT 2
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/** Time between repeated discovery attempts */
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#define PEERDISC_REPEAT_TIMEOUT ( 1 * TICKS_PER_SEC )
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/** Default discovery timeout (in seconds) */
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#define PEERDISC_DEFAULT_TIMEOUT_SECS 2
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/** Recommended discovery timeout (in seconds)
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*
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* We reduce the recommended discovery timeout whenever a segment
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* fails to discover any peers, and restore the default value whenever
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* a valid discovery reply is received. We continue to send discovery
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* requests even if the recommended timeout is reduced to zero.
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*
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* This strategy is intended to minimise discovery delays when no
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* peers are available on the network, while allowing downloads to
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* quickly switch back to using PeerDist acceleration if new peers
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* become available.
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*/
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unsigned int peerdisc_timeout_secs = PEERDISC_DEFAULT_TIMEOUT_SECS;
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static struct peerdisc_segment * peerdisc_find ( const char *id );
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static int peerdisc_discovered ( struct peerdisc_segment *segment,
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const char *location );
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/******************************************************************************
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*
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* Discovery sockets
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*
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******************************************************************************
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*/
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/**
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* Open all PeerDist discovery sockets
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*
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* @ret rc Return status code
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*/
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static int peerdisc_socket_open ( void ) {
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struct peerdisc_socket *socket;
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int rc;
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/* Open each socket */
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for_each_table_entry ( socket, PEERDISC_SOCKETS ) {
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if ( ( rc = xfer_open_socket ( &socket->xfer, SOCK_DGRAM,
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&socket->address.sa,
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NULL ) ) != 0 ) {
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DBGC ( socket, "PEERDISC %s could not open socket: "
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"%s\n", socket->name, strerror ( rc ) );
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goto err;
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}
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}
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return 0;
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err:
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for_each_table_entry_continue_reverse ( socket, PEERDISC_SOCKETS )
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intf_restart ( &socket->xfer, rc );
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return rc;
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}
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/**
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* Attempt to transmit PeerDist discovery requests on all sockets
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*
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* @v uuid Message UUID string
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* @v id Segment identifier string
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*/
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static void peerdisc_socket_tx ( const char *uuid, const char *id ) {
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struct peerdisc_socket *socket;
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struct net_device *netdev;
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struct xfer_metadata meta;
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union {
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struct sockaddr sa;
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struct sockaddr_tcpip st;
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} address;
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char *request;
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size_t len;
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int rc;
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/* Construct discovery request */
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request = peerdist_discovery_request ( uuid, id );
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if ( ! request )
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goto err_request;
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len = strlen ( request );
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/* Initialise data transfer metadata */
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memset ( &meta, 0, sizeof ( meta ) );
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meta.dest = &address.sa;
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/* Send message on each socket */
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for_each_table_entry ( socket, PEERDISC_SOCKETS ) {
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/* Initialise socket address */
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memcpy ( &address.sa, &socket->address.sa,
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sizeof ( address.sa ) );
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/* Send message on each open network device */
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for_each_netdev ( netdev ) {
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/* Skip unopened network devices */
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if ( ! netdev_is_open ( netdev ) )
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continue;
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address.st.st_scope_id = netdev->index;
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/* Discard request (for test purposes) if applicable */
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if ( inject_fault ( PEERDISC_DISCARD_RATE ) )
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continue;
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/* Transmit request */
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if ( ( rc = xfer_deliver_raw_meta ( &socket->xfer,
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request, len,
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&meta ) ) != 0 ) {
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DBGC ( socket, "PEERDISC %s could not transmit "
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"via %s: %s\n", socket->name,
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netdev->name, strerror ( rc ) );
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/* Contine to try other net devices/sockets */
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continue;
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}
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}
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}
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free ( request );
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err_request:
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return;
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}
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/**
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* Handle received PeerDist discovery reply
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*
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* @v socket PeerDist discovery socket
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* @v iobuf I/O buffer
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* @v meta Data transfer metadata
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* @ret rc Return status code
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*/
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static int peerdisc_socket_rx ( struct peerdisc_socket *socket,
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struct io_buffer *iobuf,
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struct xfer_metadata *meta __unused ) {
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struct peerdist_discovery_reply reply;
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struct peerdisc_segment *segment;
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char *id;
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char *location;
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int rc;
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/* Discard reply (for test purposes) if applicable */
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if ( ( rc = inject_fault ( PEERDISC_DISCARD_RATE ) ) != 0 )
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goto err;
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/* Parse reply */
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if ( ( rc = peerdist_discovery_reply ( iobuf->data, iob_len ( iobuf ),
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&reply ) ) != 0 ) {
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DBGC ( socket, "PEERDISC %s could not parse reply: %s\n",
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socket->name, strerror ( rc ) );
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DBGC_HDA ( socket, 0, iobuf->data, iob_len ( iobuf ) );
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goto err;
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}
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/* Any kind of discovery reply indicates that there are active
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* peers on a local network, so restore the recommended
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* discovery timeout to its default value for future requests.
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*/
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if ( peerdisc_timeout_secs != PEERDISC_DEFAULT_TIMEOUT_SECS ) {
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DBGC ( socket, "PEERDISC %s restoring timeout to %d seconds\n",
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socket->name, PEERDISC_DEFAULT_TIMEOUT_SECS );
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}
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peerdisc_timeout_secs = PEERDISC_DEFAULT_TIMEOUT_SECS;
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/* Iterate over segment IDs */
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for ( id = reply.ids ; *id ; id += ( strlen ( id ) + 1 /* NUL */ ) ) {
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/* Find corresponding segment */
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segment = peerdisc_find ( id );
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if ( ! segment ) {
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DBGC ( socket, "PEERDISC %s ignoring reply for %s\n",
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socket->name, id );
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continue;
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}
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/* Report all discovered peer locations */
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for ( location = reply.locations ; *location ;
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location += ( strlen ( location ) + 1 /* NUL */ ) ) {
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/* Report discovered peer location */
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if ( ( rc = peerdisc_discovered ( segment,
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location ) ) != 0 )
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goto err;
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}
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}
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err:
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free_iob ( iobuf );
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return rc;
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}
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/**
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* Close all PeerDist discovery sockets
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*
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* @v rc Reason for close
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*/
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static void peerdisc_socket_close ( int rc ) {
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struct peerdisc_socket *socket;
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/* Close all sockets */
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for_each_table_entry ( socket, PEERDISC_SOCKETS )
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intf_restart ( &socket->xfer, rc );
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}
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/** PeerDist discovery socket interface operations */
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static struct interface_operation peerdisc_socket_operations[] = {
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INTF_OP ( xfer_deliver, struct peerdisc_socket *, peerdisc_socket_rx ),
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};
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/** PeerDist discovery socket interface descriptor */
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static struct interface_descriptor peerdisc_socket_desc =
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INTF_DESC ( struct peerdisc_socket, xfer, peerdisc_socket_operations );
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/** PeerDist discovery IPv4 socket */
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struct peerdisc_socket peerdisc_socket_ipv4 __peerdisc_socket = {
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.name = "IPv4",
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.address = {
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.sin = {
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.sin_family = AF_INET,
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.sin_port = htons ( PEERDIST_DISCOVERY_PORT ),
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.sin_addr.s_addr = htonl ( PEERDIST_DISCOVERY_IPV4 ),
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},
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},
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.xfer = INTF_INIT ( peerdisc_socket_desc ),
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};
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/** PeerDist discovery IPv6 socket */
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struct peerdisc_socket peerdisc_socket_ipv6 __peerdisc_socket = {
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.name = "IPv6",
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.address = {
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.sin6 = {
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.sin6_family = AF_INET6,
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.sin6_port = htons ( PEERDIST_DISCOVERY_PORT ),
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.sin6_addr.s6_addr = PEERDIST_DISCOVERY_IPV6,
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},
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},
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.xfer = INTF_INIT ( peerdisc_socket_desc ),
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};
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/******************************************************************************
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*
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* Discovery segments
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*
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******************************************************************************
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*/
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/**
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* Free PeerDist discovery segment
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*
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* @v refcnt Reference count
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*/
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static void peerdisc_free ( struct refcnt *refcnt ) {
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struct peerdisc_segment *segment =
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container_of ( refcnt, struct peerdisc_segment, refcnt );
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struct peerdisc_peer *peer;
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struct peerdisc_peer *tmp;
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/* Free all discovered peers */
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list_for_each_entry_safe ( peer, tmp, &segment->peers, list ) {
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list_del ( &peer->list );
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free ( peer );
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}
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/* Free segment */
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free ( segment );
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}
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/**
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* Find PeerDist discovery segment
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*
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* @v id Segment ID
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* @ret segment PeerDist discovery segment, or NULL if not found
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*/
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static struct peerdisc_segment * peerdisc_find ( const char *id ) {
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struct peerdisc_segment *segment;
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/* Look for a matching segment */
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list_for_each_entry ( segment, &peerdisc_segments, list ) {
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if ( strcmp ( id, segment->id ) == 0 )
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return segment;
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}
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return NULL;
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}
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/**
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* Add discovered PeerDist peer
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*
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* @v segment PeerDist discovery segment
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* @v location Peer location
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* @ret rc Return status code
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*/
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static int peerdisc_discovered ( struct peerdisc_segment *segment,
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const char *location ) {
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struct peerdisc_peer *peer;
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struct peerdisc_client *peerdisc;
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struct peerdisc_client *tmp;
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/* Ignore duplicate peers */
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list_for_each_entry ( peer, &segment->peers, list ) {
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if ( strcmp ( peer->location, location ) == 0 ) {
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DBGC2 ( segment, "PEERDISC %p duplicate %s\n",
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segment, location );
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return 0;
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}
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}
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DBGC2 ( segment, "PEERDISC %p discovered %s\n", segment, location );
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/* Allocate and initialise structure */
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peer = zalloc ( sizeof ( *peer ) + strlen ( location ) + 1 /* NUL */ );
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if ( ! peer )
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return -ENOMEM;
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strcpy ( peer->location, location );
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/* Add to end of list of peers */
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list_add_tail ( &peer->list, &segment->peers );
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/* Notify all clients */
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list_for_each_entry_safe ( peerdisc, tmp, &segment->clients, list )
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peerdisc->op->discovered ( peerdisc );
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return 0;
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}
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/**
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* Handle discovery timer expiry
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*
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* @v timer Discovery timer
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* @v over Failure indicator
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*/
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static void peerdisc_expired ( struct retry_timer *timer, int over __unused ) {
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struct peerdisc_segment *segment =
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container_of ( timer, struct peerdisc_segment, timer );
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/* Attempt to transmit discovery requests */
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peerdisc_socket_tx ( segment->uuid, segment->id );
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/* Schedule next transmission, if applicable */
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if ( timer->count < PEERDISC_REPEAT_COUNT )
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start_timer_fixed ( &segment->timer, PEERDISC_REPEAT_TIMEOUT );
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}
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/**
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* Create PeerDist discovery segment
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*
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* @v id Segment ID
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* @ret segment PeerDist discovery segment, or NULL on error
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*/
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static struct peerdisc_segment * peerdisc_create ( const char *id ) {
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struct peerdisc_segment *segment;
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union {
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union uuid uuid;
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uint32_t dword[ sizeof ( union uuid ) / sizeof ( uint32_t ) ];
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} random_uuid;
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size_t uuid_len;
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size_t id_len;
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char *uuid;
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char *uuid_copy;
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char *id_copy;
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unsigned int i;
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/* Generate a random message UUID. This does not require high
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* quality randomness.
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*/
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for ( i = 0 ; i < ( sizeof ( random_uuid.dword ) /
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sizeof ( random_uuid.dword[0] ) ) ; i++ )
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random_uuid.dword[i] = random();
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uuid = uuid_ntoa ( &random_uuid.uuid );
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/* Calculate string lengths */
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id_len = ( strlen ( id ) + 1 /* NUL */ );
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uuid_len = ( strlen ( uuid ) + 1 /* NUL */ );
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/* Allocate and initialise structure */
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segment = zalloc ( sizeof ( *segment ) + id_len + uuid_len );
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if ( ! segment )
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return NULL;
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id_copy = ( ( ( void * ) segment ) + sizeof ( *segment ) );
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memcpy ( id_copy, id, id_len );
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uuid_copy = ( ( ( void * ) id_copy ) + id_len );
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memcpy ( uuid_copy, uuid, uuid_len );
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ref_init ( &segment->refcnt, peerdisc_free );
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segment->id = id_copy;
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segment->uuid = uuid_copy;
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INIT_LIST_HEAD ( &segment->peers );
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INIT_LIST_HEAD ( &segment->clients );
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timer_init ( &segment->timer, peerdisc_expired, &segment->refcnt );
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DBGC2 ( segment, "PEERDISC %p discovering %s\n", segment, segment->id );
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/* Start discovery timer */
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start_timer_nodelay ( &segment->timer );
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/* Add to list of segments, transfer reference to list, and return */
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list_add_tail ( &segment->list, &peerdisc_segments );
|
||
|
return segment;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Destroy PeerDist discovery segment
|
||
|
*
|
||
|
* @v segment PeerDist discovery segment
|
||
|
*/
|
||
|
static void peerdisc_destroy ( struct peerdisc_segment *segment ) {
|
||
|
|
||
|
/* Sanity check */
|
||
|
assert ( list_empty ( &segment->clients ) );
|
||
|
|
||
|
/* Stop timer */
|
||
|
stop_timer ( &segment->timer );
|
||
|
|
||
|
/* Remove from list of segments and drop list's reference */
|
||
|
list_del ( &segment->list );
|
||
|
ref_put ( &segment->refcnt );
|
||
|
}
|
||
|
|
||
|
/******************************************************************************
|
||
|
*
|
||
|
* Discovery clients
|
||
|
*
|
||
|
******************************************************************************
|
||
|
*/
|
||
|
|
||
|
/**
|
||
|
* Open PeerDist discovery client
|
||
|
*
|
||
|
* @v peerdisc PeerDist discovery client
|
||
|
* @v id Segment ID
|
||
|
* @v len Length of segment ID
|
||
|
* @ret rc Return status code
|
||
|
*/
|
||
|
int peerdisc_open ( struct peerdisc_client *peerdisc, const void *id,
|
||
|
size_t len ) {
|
||
|
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;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Close PeerDist discovery client
|
||
|
*
|
||
|
* @v peerdisc PeerDist discovery client
|
||
|
*/
|
||
|
void peerdisc_close ( struct peerdisc_client *peerdisc ) {
|
||
|
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 );
|
||
|
}
|