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