--- /dev/null
+/*
+ * 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 );
+
+/******************************************************************************
+ *
+ * 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;
+ 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 );
+}
Code Review / kvmfornfv.git / blobdiff