/*
* 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 <stdio.h>
#include <errno.h>
#include <ipxe/http.h>
#include <ipxe/iobuf.h>
#include <ipxe/xfer.h>
#include <ipxe/uri.h>
#include <ipxe/timer.h>
#include <ipxe/profile.h>
#include <ipxe/fault.h>
#include <ipxe/pccrr.h>
#include <ipxe/peerblk.h>
/** @file
*
* Peer Content Caching and Retrieval (PeerDist) protocol block downloads
*
*/
/** PeerDist decryption chunksize
*
* This is a policy decision.
*/
#define PEERBLK_DECRYPT_CHUNKSIZE 2048
/** PeerDist maximum number of concurrent raw block downloads
*
* Raw block downloads are expensive if the origin server uses HTTPS,
* since each concurrent download will require local TLS resources
* (including potentially large received encrypted data buffers).
*
* Raw block downloads may also be prohibitively slow to initiate when
* the origin server is using HTTPS and client certificates. Origin
* servers for PeerDist downloads are likely to be running IIS, which
* has a bug that breaks session resumption and requires each
* connection to go through the full client certificate verification.
*
* Limit the total number of concurrent raw block downloads to
* ameliorate these problems.
*
* This is a policy decision.
*/
#define PEERBLK_RAW_MAX 2
/** PeerDist raw block download attempt initial progress timeout
*
* This is a policy decision.
*/
#define PEERBLK_RAW_OPEN_TIMEOUT ( 10 * TICKS_PER_SEC )
/** PeerDist raw block download attempt ongoing progress timeout
*
* This is a policy decision.
*/
#define PEERBLK_RAW_RX_TIMEOUT ( 15 * TICKS_PER_SEC )
/** PeerDist retrieval protocol block download attempt initial progress timeout
*
* This is a policy decision.
*/
#define PEERBLK_RETRIEVAL_OPEN_TIMEOUT ( 3 * TICKS_PER_SEC )
/** PeerDist retrieval protocol block download attempt ongoing progress timeout
*
* This is a policy decision.
*/
#define PEERBLK_RETRIEVAL_RX_TIMEOUT ( 5 * TICKS_PER_SEC )
/** PeerDist maximum number of full download attempt cycles
*
* This is the maximum number of times that we will try a full cycle
* of download attempts (i.e. a retrieval protocol download attempt
* from each discovered peer plus a raw download attempt from the
* origin server).
*
* This is a policy decision.
*/
#define PEERBLK_MAX_ATTEMPT_CYCLES 4
/** PeerDist block download profiler */
static struct profiler peerblk_download_profiler __profiler =
{ .name = "peerblk.download" };
/** PeerDist block download attempt success profiler */
static struct profiler peerblk_attempt_success_profiler __profiler =
{ .name = "peerblk.attempt.success" };
/** PeerDist block download attempt failure profiler */
static struct profiler peerblk_attempt_failure_profiler __profiler =
{ .name = "peerblk.attempt.failure" };
/** PeerDist block download attempt timeout profiler */
static struct profiler peerblk_attempt_timeout_profiler __profiler =
{ .name = "peerblk.attempt.timeout" };
/** PeerDist block download discovery success profiler */
static struct profiler peerblk_discovery_success_profiler __profiler =
{ .name = "peerblk.discovery.success" };
/** PeerDist block download discovery timeout profiler */
static struct profiler peerblk_discovery_timeout_profiler __profiler =
{ .name = "peerblk.discovery.timeout" };
static void peerblk_dequeue ( struct peerdist_block *peerblk );
/**
* Get profiling timestamp
*
* @ret timestamp Timestamp
*/
static inline __attribute__ (( always_inline )) unsigned long
peerblk_timestamp ( void ) {
if ( PROFILING ) {
return currticks();
} else {
return 0;
}
}
/**
* Free PeerDist block download
*
* @v refcnt Reference count
*/
static void peerblk_free ( struct refcnt *refcnt ) {
struct peerdist_block *peerblk =
container_of ( refcnt, struct peerdist_block, refcnt );
uri_put ( peerblk->uri );
free ( peerblk->cipherctx );
free ( peerblk );
}
/**
* Reset PeerDist block download attempt
*
* @v peerblk PeerDist block download
* @v rc Reason for reset
*/
static void peerblk_reset ( struct peerdist_block *peerblk, int rc ) {
/* Stop decryption process */
process_del ( &peerblk->process );
/* Stop timer */
stop_timer ( &peerblk->timer );
/* Abort any current download attempt */
intf_restart ( &peerblk->raw, rc );
intf_restart ( &peerblk->retrieval, rc );
/* Remove from download queue, if applicable */
if ( peerblk->queue )
peerblk_dequeue ( peerblk );
/* Empty received data buffer */
xferbuf_free ( &peerblk->buffer );
peerblk->pos = 0;
/* Reset digest and free cipher context */
digest_init ( peerblk->digest, peerblk->digestctx );
free ( peerblk->cipherctx );
peerblk->cipherctx = NULL;
peerblk->cipher = NULL;
/* Reset trim thresholds */
peerblk->start = ( peerblk->trim.start - peerblk->range.start );
peerblk->end = ( peerblk->trim.end - peerblk->range.start );
assert ( peerblk->start <= peerblk->end );
}
/**
* Close PeerDist block download
*
* @v peerblk PeerDist block download
* @v rc Reason for close
*/
static void peerblk_close ( struct peerdist_block *peerblk, int rc ) {
unsigned long now = peerblk_timestamp();
/* Profile overall block download */
profile_custom ( &peerblk_download_profiler,
( now - peerblk->started ) );
/* Reset download attempt */
peerblk_reset ( peerblk, rc );
/* Close discovery */
peerdisc_close ( &peerblk->discovery );
/* Shut down all interfaces */
intf_shutdown ( &peerblk->retrieval, rc );
intf_shutdown ( &peerblk->raw, rc );
intf_shutdown ( &peerblk->xfer, rc );
}
/**
* Calculate offset within overall download
*
* @v peerblk PeerDist block download
* @v pos Position within incoming data stream
* @ret offset Offset within overall download
*/
static inline __attribute__ (( always_inline )) size_t
peerblk_offset ( struct peerdist_block *peerblk, size_t pos ) {
return ( ( pos - peerblk->start ) + peerblk->offset );
}
/**
* Deliver download attempt data block
*
* @v peerblk PeerDist block download
* @v iobuf I/O buffer
* @v meta Original data transfer metadata
* @v pos Position within incoming data stream
* @ret rc Return status code
*/
static int peerblk_deliver ( struct peerdist_block *peerblk,
struct io_buffer *iobuf,
struct xfer_metadata *meta, size_t pos ) {
struct xfer_metadata xfer_meta;
size_t len = iob_len ( iobuf );
size_t start = pos;
size_t end = ( pos + len );
int rc;
/* Discard zero-length packets and packets which lie entirely
* outside the trimmed range.
*/
if ( ( start >= peerblk->end ) || ( end <= peerblk->start ) ||
( len == 0 ) ) {
free_iob ( iobuf );
return 0;
}
/* Truncate data to within trimmed range */
if ( start < peerblk->start ) {
iob_pull ( iobuf, ( peerblk->start - start ) );
start = peerblk->start;
}
if ( end > peerblk->end ) {
iob_unput ( iobuf, ( end - peerblk->end ) );
end = peerblk->end;
}
/* Construct metadata */
memcpy ( &xfer_meta, meta, sizeof ( xfer_meta ) );
xfer_meta.flags |= XFER_FL_ABS_OFFSET;
xfer_meta.offset = peerblk_offset ( peerblk, start );
/* Deliver data */
if ( ( rc = xfer_deliver ( &peerblk->xfer, iob_disown ( iobuf ),
&xfer_meta ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not deliver data: %s\n",
peerblk, peerblk->segment, peerblk->block,
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Finish PeerDist block download attempt
*
* @v peerblk PeerDist block download
* @v rc Reason for close
*/
static void peerblk_done ( struct peerdist_block *peerblk, int rc ) {
struct digest_algorithm *digest = peerblk->digest;
struct peerdisc_segment *segment = peerblk->discovery.segment;
struct peerdisc_peer *head;
struct peerdisc_peer *peer;
uint8_t hash[digest->digestsize];
unsigned long now = peerblk_timestamp();
/* Check for errors on completion */
if ( rc != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d attempt failed: %s\n",
peerblk, peerblk->segment, peerblk->block,
strerror ( rc ) );
goto err;
}
/* Check digest */
digest_final ( digest, peerblk->digestctx, hash );
if ( memcmp ( hash, peerblk->hash, peerblk->digestsize ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d digest mismatch:\n",
peerblk, peerblk->segment, peerblk->block );
DBGC_HDA ( peerblk, 0, hash, peerblk->digestsize );
DBGC_HDA ( peerblk, 0, peerblk->hash, peerblk->digestsize );
rc = -EIO;
goto err;
}
/* Profile successful attempt */
profile_custom ( &peerblk_attempt_success_profiler,
( now - peerblk->attempted ) );
/* Report peer statistics */
head = list_entry ( &segment->peers, struct peerdisc_peer, list );
peer = ( ( peerblk->peer == head ) ? NULL : peerblk->peer );
peerdisc_stat ( &peerblk->xfer, peer, &segment->peers );
/* Close download */
peerblk_close ( peerblk, 0 );
return;
err:
/* Record failure reason and schedule a retry attempt */
profile_custom ( &peerblk_attempt_failure_profiler,
( now - peerblk->attempted ) );
peerblk_reset ( peerblk, rc );
peerblk->rc = rc;
start_timer_nodelay ( &peerblk->timer );
}
/******************************************************************************
*
* Raw block download attempts (using an HTTP range request)
*
******************************************************************************
*/
/**
* Open PeerDist raw block download attempt
*
* @v peerblk PeerDist block download
* @ret rc Return status code
*/
static int peerblk_raw_open ( struct peerdist_block *peerblk ) {
struct http_request_range range;
int rc;
DBGC2 ( peerblk, "PEERBLK %p %d.%d attempting raw range request\n",
peerblk, peerblk->segment, peerblk->block );
/* Construct HTTP range */
memset ( &range, 0, sizeof ( range ) );
range.start = peerblk->range.start;
range.len = ( peerblk->range.end - peerblk->range.start );
/* Initiate range request to retrieve block */
if ( ( rc = http_open ( &peerblk->raw, &http_get, peerblk->uri,
&range, NULL ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not create range "
"request: %s\n", peerblk, peerblk->segment,
peerblk->block, strerror ( rc ) );
return rc;
}
/* Annul HTTP connection (for testing) if applicable. Do not
* report as an immediate error, in order to test our ability
* to recover from a totally unresponsive HTTP server.
*/
if ( inject_fault ( PEERBLK_ANNUL_RATE ) )
intf_restart ( &peerblk->raw, 0 );
/* Start download attempt timer */
peerblk->rc = -ETIMEDOUT;
start_timer_fixed ( &peerblk->timer, PEERBLK_RAW_OPEN_TIMEOUT );
return 0;
}
/**
* Receive PeerDist raw data
*
* @v peerblk PeerDist block download
* @v iobuf I/O buffer
* @v meta Data transfer metadata
* @ret rc Return status code
*/
static int peerblk_raw_rx ( struct peerdist_block *peerblk,
struct io_buffer *iobuf,
struct xfer_metadata *meta ) {
size_t len = iob_len ( iobuf );
size_t pos = peerblk->pos;
size_t mid = ( ( peerblk->range.end - peerblk->range.start ) / 2 );
int rc;
/* Corrupt received data (for testing) if applicable */
inject_corruption ( PEERBLK_CORRUPT_RATE, iobuf->data, len );
/* Fail if data is delivered out of order, since the streaming
* digest requires strict ordering.
*/
if ( ( rc = xfer_check_order ( meta, &peerblk->pos, len ) ) != 0 )
goto err;
/* Add data to digest */
digest_update ( peerblk->digest, peerblk->digestctx, iobuf->data, len );
/* Deliver data */
if ( ( rc = peerblk_deliver ( peerblk, iob_disown ( iobuf ), meta,
pos ) ) != 0 )
goto err;
/* Extend download attempt timer */
start_timer_fixed ( &peerblk->timer, PEERBLK_RAW_RX_TIMEOUT );
/* Stall download attempt (for testing) if applicable */
if ( ( pos < mid ) && ( ( pos + len ) >= mid ) &&
( ( rc = inject_fault ( PEERBLK_STALL_RATE ) ) != 0 ) ) {
intf_restart ( &peerblk->raw, rc );
}
return 0;
err:
free_iob ( iobuf );
peerblk_done ( peerblk, rc );
return rc;
}
/**
* Close PeerDist raw block download attempt
*
* @v peerblk PeerDist block download
* @v rc Reason for close
*/
static void peerblk_raw_close ( struct peerdist_block *peerblk, int rc ) {
/* Restart interface */
intf_restart ( &peerblk->raw, rc );
/* Fail immediately if we have an error */
if ( rc != 0 )
goto done;
/* Abort download attempt (for testing) if applicable */
if ( ( rc = inject_fault ( PEERBLK_ABORT_RATE ) ) != 0 )
goto done;
done:
/* Complete download attempt */
peerblk_done ( peerblk, rc );
}
/******************************************************************************
*
* Block download queue
*
******************************************************************************
*/
/**
* PeerDist block download queue process
*
* @v queue Block download queue
*/
static void peerblk_step ( struct peerdist_block_queue *queue ) {
struct peerdist_block *peerblk;
int rc;
/* Do nothing yet if we have too many open block downloads */
if ( queue->count >= queue->max )
return;
/* Do nothing unless there are queued block downloads */
peerblk = list_first_entry ( &queue->list, struct peerdist_block,
queued );
if ( ! peerblk )
return;
/* Reschedule queue process */
process_add ( &queue->process );
/* Remove block from queue */
list_del ( &peerblk->queued );
INIT_LIST_HEAD ( &peerblk->queued );
/* Attempt download */
if ( ( rc = queue->open ( peerblk ) ) != 0 ) {
peerblk_close ( peerblk, rc );
return;
}
/* Increment open block download count */
queue->count++;
}
/**
* Add block to download queue
*
* @v peerblk PeerDist block download
* @v queue Block download queue
*/
static void peerblk_enqueue ( struct peerdist_block *peerblk,
struct peerdist_block_queue *queue ) {
/* Sanity checks */
assert ( peerblk->queue == NULL );
assert ( list_empty ( &peerblk->queued ) );
/* Add block to queue */
peerblk->queue = queue;
list_add_tail ( &peerblk->queued, &queue->list );
/* Schedule queue process */
process_add ( &queue->process );
}
/**
* Remove block from download queue
*
* @v peerblk PeerDist block download
*/
static void peerblk_dequeue ( struct peerdist_block *peerblk ) {
struct peerdist_block_queue *queue = peerblk->queue;
/* Sanity checks */
assert ( queue != NULL );
/* Remove block from queue */
peerblk->queue = NULL;
if ( list_empty ( &peerblk->queued ) ) {
/* Open download: decrement count and reschedule queue */
queue->count--;
process_add ( &queue->process );
} else {
/* Queued download: remove from queue */
list_del ( &peerblk->queued );
INIT_LIST_HEAD ( &peerblk->queued );
}
}
/** PeerDist block download queue process descriptor */
static struct process_descriptor peerblk_queue_desc =
PROC_DESC_ONCE ( struct peerdist_block_queue, process, peerblk_step );
/** Raw block download queue */
static struct peerdist_block_queue peerblk_raw_queue = {
.process = PROC_INIT ( peerblk_raw_queue.process, &peerblk_queue_desc ),
.list = LIST_HEAD_INIT ( peerblk_raw_queue.list ),
.max = PEERBLK_RAW_MAX,
.open = peerblk_raw_open,
};
/******************************************************************************
*
* Retrieval protocol block download attempts (using HTTP POST)
*
******************************************************************************
*/
/**
* Construct PeerDist retrieval protocol URI
*
* @v location Peer location
* @ret uri Retrieval URI, or NULL on error
*/
static struct uri * peerblk_retrieval_uri ( const char *location ) {
char uri_string[ 7 /* "http://" */ + strlen ( location ) +
sizeof ( PEERDIST_MAGIC_PATH /* includes NUL */ ) ];
/* Construct URI string */
snprintf ( uri_string, sizeof ( uri_string ),
( "http://%s" PEERDIST_MAGIC_PATH ), location );
/* Parse URI string */
return parse_uri ( uri_string );
}
/**
* Open PeerDist retrieval protocol block download attempt
*
* @v peerblk PeerDist block download
* @v location Peer location
* @ret rc Return status code
*/
static int peerblk_retrieval_open ( struct peerdist_block *peerblk,
const char *location ) {
size_t digestsize = peerblk->digestsize;
peerdist_msg_getblks_t ( digestsize, 1, 0 ) req;
peerblk_msg_blk_t ( digestsize, 0, 0, 0 ) *rsp;
struct http_request_content content;
struct uri *uri;
int rc;
DBGC2 ( peerblk, "PEERBLK %p %d.%d attempting retrieval from %s\n",
peerblk, peerblk->segment, peerblk->block, location );
/* Construct block fetch request */
memset ( &req, 0, sizeof ( req ) );
req.getblks.hdr.version.raw = htonl ( PEERDIST_MSG_GETBLKS_VERSION );
req.getblks.hdr.type = htonl ( PEERDIST_MSG_GETBLKS_TYPE );
req.getblks.hdr.len = htonl ( sizeof ( req ) );
req.getblks.hdr.algorithm = htonl ( PEERDIST_MSG_AES_128_CBC );
req.segment.segment.digestsize = htonl ( digestsize );
memcpy ( req.segment.id, peerblk->id, digestsize );
req.ranges.ranges.count = htonl ( 1 );
req.ranges.range[0].first = htonl ( peerblk->block );
req.ranges.range[0].count = htonl ( 1 );
/* Construct POST request content */
memset ( &content, 0, sizeof ( content ) );
content.data = &req;
content.len = sizeof ( req );
/* Construct URI */
if ( ( uri = peerblk_retrieval_uri ( location ) ) == NULL ) {
rc = -ENOMEM;
goto err_uri;
}
/* Update trim thresholds */
peerblk->start += offsetof ( typeof ( *rsp ), msg.vrf );
peerblk->end += offsetof ( typeof ( *rsp ), msg.vrf );
/* Initiate HTTP POST to retrieve block */
if ( ( rc = http_open ( &peerblk->retrieval, &http_post, uri,
NULL, &content ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not create retrieval "
"request: %s\n", peerblk, peerblk->segment,
peerblk->block, strerror ( rc ) );
goto err_open;
}
/* Annul HTTP connection (for testing) if applicable. Do not
* report as an immediate error, in order to test our ability
* to recover from a totally unresponsive HTTP server.
*/
if ( inject_fault ( PEERBLK_ANNUL_RATE ) )
intf_restart ( &peerblk->retrieval, 0 );
/* Start download attempt timer */
peerblk->rc = -ETIMEDOUT;
start_timer_fixed ( &peerblk->timer, PEERBLK_RETRIEVAL_OPEN_TIMEOUT );
err_open:
uri_put ( uri );
err_uri:
return rc;
}
/**
* Receive PeerDist retrieval protocol data
*
* @v peerblk PeerDist block download
* @v iobuf I/O buffer
* @v meta Data transfer metadata
* @ret rc Return status code
*/
static int peerblk_retrieval_rx ( struct peerdist_block *peerblk,
struct io_buffer *iobuf,
struct xfer_metadata *meta ) {
size_t len = iob_len ( iobuf );
size_t start;
size_t end;
size_t before;
size_t after;
size_t cut;
int rc;
/* Some genius at Microsoft thought it would be a great idea
* to place the AES-CBC initialisation vector *after* the
* encrypted data, thereby making it logically impossible to
* decrypt each packet as it arrives.
*
* To work around this mindless stupidity, we deliver the
* ciphertext as-is and later use xfer_buffer() to obtain
* access to the underlying data transfer buffer in order to
* perform the decryption.
*
* There will be some data both before and after the bytes
* corresponding to the trimmed plaintext: a MSG_BLK
* header/footer, some block padding for the AES-CBC cipher,
* and a possibly large quantity of unwanted ciphertext which
* is excluded from the trimmed content range. We store this
* data in a local data transfer buffer. If the amount of
* data to be stored is too large, we will fail allocation and
* so eventually fall back to using a range request (which
* does not require this kind of temporary storage
* allocation).
*/
/* Corrupt received data (for testing) if applicable */
inject_corruption ( PEERBLK_CORRUPT_RATE, iobuf->data, len );
/* Calculate start and end positions of this buffer */
start = peerblk->pos;
if ( meta->flags & XFER_FL_ABS_OFFSET )
start = 0;
start += meta->offset;
end = ( start + len );
/* Buffer any data before the trimmed content */
if ( ( start < peerblk->start ) && ( len > 0 ) ) {
/* Calculate length of data before the trimmed content */
before = ( peerblk->start - start );
if ( before > len )
before = len;
/* Buffer data before the trimmed content */
if ( ( rc = xferbuf_write ( &peerblk->buffer, start,
iobuf->data, before ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not buffer "
"data: %s\n", peerblk, peerblk->segment,
peerblk->block, strerror ( rc ) );
goto err;
}
}
/* Buffer any data after the trimmed content */
if ( ( end > peerblk->end ) && ( len > 0 ) ) {
/* Calculate length of data after the trimmed content */
after = ( end - peerblk->end );
if ( after > len )
after = len;
/* Buffer data after the trimmed content */
cut = ( peerblk->end - peerblk->start );
if ( ( rc = xferbuf_write ( &peerblk->buffer,
( end - after - cut ),
( iobuf->data + len - after ),
after ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not buffer "
"data: %s\n", peerblk, peerblk->segment,
peerblk->block, strerror ( rc ) );
goto err;
}
}
/* Deliver any remaining data */
if ( ( rc = peerblk_deliver ( peerblk, iob_disown ( iobuf ), meta,
start ) ) != 0 )
goto err;
/* Update position */
peerblk->pos = end;
/* Extend download attempt timer */
start_timer_fixed ( &peerblk->timer, PEERBLK_RETRIEVAL_RX_TIMEOUT );
/* Stall download attempt (for testing) if applicable */
if ( ( start < peerblk->end ) && ( end >= peerblk->end ) &&
( ( rc = inject_fault ( PEERBLK_STALL_RATE ) ) != 0 ) ) {
intf_restart ( &peerblk->retrieval, rc );
}
return 0;
err:
free_iob ( iobuf );
peerblk_done ( peerblk, rc );
return rc;
}
/**
* Parse retrieval protocol message header
*
* @v peerblk PeerDist block download
* @ret rc Return status code
*/
static int peerblk_parse_header ( struct peerdist_block *peerblk ) {
struct {
struct peerdist_msg_transport_header hdr;
struct peerdist_msg_header msg;
} __attribute__ (( packed )) *msg = peerblk->buffer.data;
struct cipher_algorithm *cipher;
size_t len = peerblk->buffer.len;
size_t keylen = 0;
int rc;
/* Check message length */
if ( len < sizeof ( *msg ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d message too short for header "
"(%zd bytes)\n", peerblk, peerblk->segment,
peerblk->block, len );
return -ERANGE;
}
/* Check message type */
if ( msg->msg.type != htonl ( PEERDIST_MSG_BLK_TYPE ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d unexpected message type "
"%#08x\n", peerblk, peerblk->segment, peerblk->block,
ntohl ( msg->msg.type ) );
return -EPROTO;
}
/* Determine cipher algorithm and key length */
cipher = &aes_cbc_algorithm;
switch ( msg->msg.algorithm ) {
case htonl ( PEERDIST_MSG_PLAINTEXT ) :
cipher = NULL;
break;
case htonl ( PEERDIST_MSG_AES_128_CBC ) :
keylen = ( 128 / 8 );
break;
case htonl ( PEERDIST_MSG_AES_192_CBC ) :
keylen = ( 192 / 8 );
break;
case htonl ( PEERDIST_MSG_AES_256_CBC ) :
keylen = ( 256 / 8 );
break;
default:
DBGC ( peerblk, "PEERBLK %p %d.%d unrecognised algorithm "
"%#08x\n", peerblk, peerblk->segment, peerblk->block,
ntohl ( msg->msg.algorithm ) );
return -ENOTSUP;
}
DBGC2 ( peerblk, "PEERBLK %p %d.%d using %s with %zd-bit key\n",
peerblk, peerblk->segment, peerblk->block,
( cipher ? cipher->name : "plaintext" ), ( 8 * keylen ) );
/* Sanity check key length against maximum secret length */
if ( keylen > peerblk->digestsize ) {
DBGC ( peerblk, "PEERBLK %p %d.%d %zd-byte secret too short "
"for %zd-bit key\n", peerblk, peerblk->segment,
peerblk->block, peerblk->digestsize, ( 8 * keylen ) );
return -EPROTO;
}
/* Allocate cipher context, if applicable. Freeing the cipher
* context (on error or otherwise) is handled by peerblk_reset().
*/
peerblk->cipher = cipher;
assert ( peerblk->cipherctx == NULL );
if ( cipher ) {
peerblk->cipherctx = malloc ( cipher->ctxsize );
if ( ! peerblk->cipherctx )
return -ENOMEM;
}
/* Initialise cipher, if applicable */
if ( cipher &&
( rc = cipher_setkey ( cipher, peerblk->cipherctx, peerblk->secret,
keylen ) ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d could not set key: %s\n",
peerblk, peerblk->segment, peerblk->block,
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Parse retrieval protocol message segment and block details
*
* @v peerblk PeerDist block download
* @v buf_len Length of buffered data to fill in
* @ret rc Return status code
*/
static int peerblk_parse_block ( struct peerdist_block *peerblk,
size_t *buf_len ) {
size_t digestsize = peerblk->digestsize;
peerblk_msg_blk_t ( digestsize, 0, 0, 0 ) *msg = peerblk->buffer.data;
size_t len = peerblk->buffer.len;
size_t data_len;
size_t total;
/* Check message length */
if ( len < offsetof ( typeof ( *msg ), msg.block.data ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d message too short for "
"zero-length data (%zd bytes)\n", peerblk,
peerblk->segment, peerblk->block, len );
return -ERANGE;
}
/* Check digest size */
if ( ntohl ( msg->msg.segment.segment.digestsize ) != digestsize ) {
DBGC ( peerblk, "PEERBLK %p %d.%d incorrect digest size %d\n",
peerblk, peerblk->segment, peerblk->block,
ntohl ( msg->msg.segment.segment.digestsize ) );
return -EPROTO;
}
/* Check segment ID */
if ( memcmp ( msg->msg.segment.id, peerblk->id, digestsize ) != 0 ) {
DBGC ( peerblk, "PEERBLK %p %d.%d segment ID mismatch\n",
peerblk, peerblk->segment, peerblk->block );
return -EPROTO;
}
/* Check block ID */
if ( ntohl ( msg->msg.index ) != peerblk->block ) {
DBGC ( peerblk, "PEERBLK %p %d.%d block ID mismatch (got %d)\n",
peerblk, peerblk->segment, peerblk->block,
ntohl ( msg->msg.index ) );
return -EPROTO;
}
/* Check for missing blocks */
data_len = be32_to_cpu ( msg->msg.block.block.len );
if ( ! data_len ) {
DBGC ( peerblk, "PEERBLK %p %d.%d block not found\n",
peerblk, peerblk->segment, peerblk->block );
return -ENOENT;
}
/* Check for underlength blocks */
if ( data_len < ( peerblk->range.end - peerblk->range.start ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d underlength block (%zd "
"bytes)\n", peerblk, peerblk->segment, peerblk->block,
data_len );
return -ERANGE;
}
/* Calculate buffered data length (i.e. excluding data which
* was delivered to the final data transfer buffer).
*/
*buf_len = ( data_len - ( peerblk->end - peerblk->start ) );
/* Describe data before the trimmed content */
peerblk->decrypt[PEERBLK_BEFORE].xferbuf = &peerblk->buffer;
peerblk->decrypt[PEERBLK_BEFORE].offset =
offsetof ( typeof ( *msg ), msg.block.data );
peerblk->decrypt[PEERBLK_BEFORE].len =
( peerblk->start -
offsetof ( typeof ( *msg ), msg.block.data ) );
total = peerblk->decrypt[PEERBLK_BEFORE].len;
/* Describe data within the trimmed content */
peerblk->decrypt[PEERBLK_DURING].offset =
peerblk_offset ( peerblk, peerblk->start );
peerblk->decrypt[PEERBLK_DURING].len =
( peerblk->end - peerblk->start );
total += peerblk->decrypt[PEERBLK_DURING].len;
/* Describe data after the trimmed content */
peerblk->decrypt[PEERBLK_AFTER].xferbuf = &peerblk->buffer;
peerblk->decrypt[PEERBLK_AFTER].offset = peerblk->start;
peerblk->decrypt[PEERBLK_AFTER].len =
( offsetof ( typeof ( *msg ), msg.block.data )
+ *buf_len - peerblk->start );
total += peerblk->decrypt[PEERBLK_AFTER].len;
/* Sanity check */
assert ( total == be32_to_cpu ( msg->msg.block.block.len ) );
/* Initialise cipher and digest lengths */
peerblk->cipher_remaining = total;
peerblk->digest_remaining =
( peerblk->range.end - peerblk->range.start );
assert ( peerblk->cipher_remaining >= peerblk->digest_remaining );
return 0;
}
/**
* Parse retrieval protocol message useless details
*
* @v peerblk PeerDist block download
* @v buf_len Length of buffered data
* @v vrf_len Length of uselessness to fill in
* @ret rc Return status code
*/
static int peerblk_parse_useless ( struct peerdist_block *peerblk,
size_t buf_len, size_t *vrf_len ) {
size_t digestsize = peerblk->digestsize;
peerblk_msg_blk_t ( digestsize, buf_len, 0, 0 ) *msg =
peerblk->buffer.data;
size_t len = peerblk->buffer.len;
/* Check message length */
if ( len < offsetof ( typeof ( *msg ), msg.vrf.data ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d message too short for "
"zero-length uselessness (%zd bytes)\n", peerblk,
peerblk->segment, peerblk->block, len );
return -ERANGE;
}
/* Extract length of uselessness */
*vrf_len = be32_to_cpu ( msg->msg.vrf.vrf.len );
return 0;
}
/**
* Parse retrieval protocol message initialisation vector details
*
* @v peerblk PeerDist block download
* @v buf_len Length of buffered data
* @v vrf_len Length of uselessness
* @ret rc Return status code
*/
static int peerblk_parse_iv ( struct peerdist_block *peerblk, size_t buf_len,
size_t vrf_len ) {
size_t digestsize = peerblk->digestsize;
size_t blksize = peerblk->cipher->blocksize;
peerblk_msg_blk_t ( digestsize, buf_len, vrf_len, blksize ) *msg =
peerblk->buffer.data;
size_t len = peerblk->buffer.len;
/* Check message length */
if ( len < sizeof ( *msg ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d message too short for "
"initialisation vector (%zd bytes)\n", peerblk,
peerblk->segment, peerblk->block, len );
return -ERANGE;
}
/* Check initialisation vector size */
if ( ntohl ( msg->msg.iv.iv.blksize ) != blksize ) {
DBGC ( peerblk, "PEERBLK %p %d.%d incorrect IV size %d\n",
peerblk, peerblk->segment, peerblk->block,
ntohl ( msg->msg.iv.iv.blksize ) );
return -EPROTO;
}
/* Set initialisation vector */
cipher_setiv ( peerblk->cipher, peerblk->cipherctx, msg->msg.iv.data,
blksize );
return 0;
}
/**
* Read from decryption buffers
*
* @v peerblk PeerDist block download
* @v data Data buffer
* @v len Length to read
* @ret rc Return status code
*/
static int peerblk_decrypt_read ( struct peerdist_block *peerblk,
void *data, size_t len ) {
struct peerdist_block_decrypt *decrypt = peerblk->decrypt;
size_t frag_len;
int rc;
/* Read from each decryption buffer in turn */
for ( ; len ; decrypt++, data += frag_len, len -= frag_len ) {
/* Calculate length to use from this buffer */
frag_len = decrypt->len;
if ( frag_len > len )
frag_len = len;
if ( ! frag_len )
continue;
/* Read from this buffer */
if ( ( rc = xferbuf_read ( decrypt->xferbuf, decrypt->offset,
data, frag_len ) ) != 0 )
return rc;
}
return 0;
}
/**
* Write to decryption buffers and update offsets and lengths
*
* @v peerblk PeerDist block download
* @v data Data buffer
* @v len Length to read
* @ret rc Return status code
*/
static int peerblk_decrypt_write ( struct peerdist_block *peerblk,
const void *data, size_t len ) {
struct peerdist_block_decrypt *decrypt = peerblk->decrypt;
size_t frag_len;
int rc;
/* Write to each decryption buffer in turn */
for ( ; len ; decrypt++, data += frag_len, len -= frag_len ) {
/* Calculate length to use from this buffer */
frag_len = decrypt->len;
if ( frag_len > len )
frag_len = len;
if ( ! frag_len )
continue;
/* Write to this buffer */
if ( ( rc = xferbuf_write ( decrypt->xferbuf, decrypt->offset,
data, frag_len ) ) != 0 )
return rc;
/* Update offset and length */
decrypt->offset += frag_len;
decrypt->len -= frag_len;
}
return 0;
}
/**
* Decrypt one chunk of PeerDist retrieval protocol data
*
* @v peerblk PeerDist block download
*/
static void peerblk_decrypt ( struct peerdist_block *peerblk ) {
struct cipher_algorithm *cipher = peerblk->cipher;
struct digest_algorithm *digest = peerblk->digest;
struct xfer_buffer *xferbuf;
size_t cipher_len;
size_t digest_len;
void *data;
int rc;
/* Sanity check */
assert ( ( PEERBLK_DECRYPT_CHUNKSIZE % cipher->blocksize ) == 0 );
/* Get the underlying data transfer buffer */
xferbuf = xfer_buffer ( &peerblk->xfer );
if ( ! xferbuf ) {
DBGC ( peerblk, "PEERBLK %p %d.%d has no underlying data "
"transfer buffer\n", peerblk, peerblk->segment,
peerblk->block );
rc = -ENOTSUP;
goto err_xfer_buffer;
}
peerblk->decrypt[PEERBLK_DURING].xferbuf = xferbuf;
/* Calculate cipher and digest lengths */
cipher_len = PEERBLK_DECRYPT_CHUNKSIZE;
if ( cipher_len > peerblk->cipher_remaining )
cipher_len = peerblk->cipher_remaining;
digest_len = cipher_len;
if ( digest_len > peerblk->digest_remaining )
digest_len = peerblk->digest_remaining;
assert ( ( cipher_len & ( cipher->blocksize - 1 ) ) == 0 );
/* Allocate temporary data buffer */
data = malloc ( cipher_len );
if ( ! data ) {
rc = -ENOMEM;
goto err_alloc_data;
}
/* Read ciphertext */
if ( ( rc = peerblk_decrypt_read ( peerblk, data, cipher_len ) ) != 0 ){
DBGC ( peerblk, "PEERBLK %p %d.%d could not read ciphertext: "
"%s\n", peerblk, peerblk->segment, peerblk->block,
strerror ( rc ) );
goto err_read;
}
/* Decrypt data */
cipher_decrypt ( cipher, peerblk->cipherctx, data, data, cipher_len );
/* Add data to digest */
digest_update ( digest, peerblk->digestctx, data, digest_len );
/* Write plaintext */
if ( ( rc = peerblk_decrypt_write ( peerblk, data, cipher_len ) ) != 0){
DBGC ( peerblk, "PEERBLK %p %d.%d could not write plaintext: "
"%s\n", peerblk, peerblk->segment, peerblk->block,
strerror ( rc ) );
goto err_write;
}
/* Consume input */
peerblk->cipher_remaining -= cipher_len;
peerblk->digest_remaining -= digest_len;
/* Free temporary data buffer */
free ( data );
/* Continue processing until all input is consumed */
if ( peerblk->cipher_remaining )
return;
/* Complete download attempt */
peerblk_done ( peerblk, 0 );
return;
err_write:
err_read:
free ( data );
err_alloc_data:
err_xfer_buffer:
peerblk_done ( peerblk, rc );
}
/**
* Close PeerDist retrieval protocol block download attempt
*
* @v peerblk PeerDist block download
* @v rc Reason for close
*/
static void peerblk_retrieval_close ( struct peerdist_block *peerblk, int rc ) {
size_t buf_len;
size_t vrf_len;
/* Restart interface */
intf_restart ( &peerblk->retrieval, rc );
/* Fail immediately if we have an error */
if ( rc != 0 )
goto done;
/* Abort download attempt (for testing) if applicable */
if ( ( rc = inject_fault ( PEERBLK_ABORT_RATE ) ) != 0 )
goto done;
/* Parse message header */
if ( ( rc = peerblk_parse_header ( peerblk ) ) != 0 )
goto done;
/* Parse message segment and block details */
if ( ( rc = peerblk_parse_block ( peerblk, &buf_len ) ) != 0 )
goto done;
/* If the block was plaintext, then there is nothing more to do */
if ( ! peerblk->cipher )
goto done;
/* Parse message useless details */
if ( ( rc = peerblk_parse_useless ( peerblk, buf_len, &vrf_len ) ) != 0)
goto done;
/* Parse message initialisation vector details */
if ( ( rc = peerblk_parse_iv ( peerblk, buf_len, vrf_len ) ) != 0 )
goto done;
/* Fail if decryption length is not aligned to the cipher block size */
if ( peerblk->cipher_remaining & ( peerblk->cipher->blocksize - 1 ) ) {
DBGC ( peerblk, "PEERBLK %p %d.%d unaligned data length %zd\n",
peerblk, peerblk->segment, peerblk->block,
peerblk->cipher_remaining );
rc = -EPROTO;
goto done;
}
/* Stop the download attempt timer: there is no point in
* timing out while decrypting.
*/
stop_timer ( &peerblk->timer );
/* Start decryption process */
process_add ( &peerblk->process );
return;
done:
/* Complete download attempt */
peerblk_done ( peerblk, rc );
}
/******************************************************************************
*
* Retry policy
*
******************************************************************************
*/
/**
* Handle PeerDist retry timer expiry
*
* @v timer Retry timer
* @v over Failure indicator
*/
static void peerblk_expired ( struct retry_timer *timer, int over __unused ) {
struct peerdist_block *peerblk =
container_of ( timer, struct peerdist_block, timer );
struct peerdisc_segment *segment = peerblk->discovery.segment;
struct peerdisc_peer *head;
unsigned long now = peerblk_timestamp();
const char *location;
int rc;
/* Profile discovery timeout, if applicable */
if ( ( peerblk->peer == NULL ) && ( timer->timeout != 0 ) ) {
profile_custom ( &peerblk_discovery_timeout_profiler,
( now - peerblk->started ) );
DBGC ( peerblk, "PEERBLK %p %d.%d discovery timed out after "
"%ld ticks\n", peerblk, peerblk->segment,
peerblk->block, timer->timeout );
}
/* Profile download timeout, if applicable */
if ( ( peerblk->peer != NULL ) && ( timer->timeout != 0 ) ) {
profile_custom ( &peerblk_attempt_timeout_profiler,
( now - peerblk->attempted ) );
DBGC ( peerblk, "PEERBLK %p %d.%d timed out after %ld ticks\n",
peerblk, peerblk->segment, peerblk->block,
timer->timeout );
}
/* Abort any current download attempt */
peerblk_reset ( peerblk, -ETIMEDOUT );
/* Record attempt start time */
peerblk->attempted = now;
/* If we have exceeded our maximum number of attempt cycles
* (each cycle comprising a retrieval protocol download from
* each peer in the list followed by a raw download from the
* origin server), then abort the overall download.
*/
head = list_entry ( &segment->peers, struct peerdisc_peer, list );
if ( ( peerblk->peer == head ) &&
( ++peerblk->cycles >= PEERBLK_MAX_ATTEMPT_CYCLES ) ) {
rc = peerblk->rc;
assert ( rc != 0 );
goto err;
}
/* If we have not yet made any download attempts, then move to
* the start of the peer list.
*/
if ( peerblk->peer == NULL )
peerblk->peer = head;
/* Attempt retrieval protocol download from next usable peer */
list_for_each_entry_continue ( peerblk->peer, &segment->peers, list ) {
/* Attempt retrieval protocol download from this peer */
location = peerblk->peer->location;
if ( ( rc = peerblk_retrieval_open ( peerblk,
location ) ) != 0 ) {
/* Non-fatal: continue to try next peer */
continue;
}
/* Peer download started */
return;
}
/* Add to raw download queue */
peerblk_enqueue ( peerblk, &peerblk_raw_queue );
return;
err:
peerblk_close ( peerblk, rc );
}
/**
* Handle PeerDist peer discovery
*
* @v discovery PeerDist discovery client
*/
static void peerblk_discovered ( struct peerdisc_client *discovery ) {
struct peerdist_block *peerblk =
container_of ( discovery, struct peerdist_block, discovery );
unsigned long now = peerblk_timestamp();
/* Do nothing unless we are still waiting for the initial
* discovery timeout.
*/
if ( ( peerblk->peer != NULL ) || ( peerblk->timer.timeout == 0 ) )
return;
/* Schedule an immediate retry */
start_timer_nodelay ( &peerblk->timer );
/* Profile discovery success */
profile_custom ( &peerblk_discovery_success_profiler,
( now - peerblk->started ) );
}
/******************************************************************************
*
* Opener
*
******************************************************************************
*/
/** PeerDist block download data transfer interface operations */
static struct interface_operation peerblk_xfer_operations[] = {
INTF_OP ( intf_close, struct peerdist_block *, peerblk_close ),
};
/** PeerDist block download data transfer interface descriptor */
static struct interface_descriptor peerblk_xfer_desc =
INTF_DESC ( struct peerdist_block, xfer, peerblk_xfer_operations );
/** PeerDist block download raw data interface operations */
static struct interface_operation peerblk_raw_operations[] = {
INTF_OP ( xfer_deliver, struct peerdist_block *, peerblk_raw_rx ),
INTF_OP ( intf_close, struct peerdist_block *, peerblk_raw_close ),
};
/** PeerDist block download raw data interface descriptor */
static struct interface_descriptor peerblk_raw_desc =
INTF_DESC ( struct peerdist_block, raw, peerblk_raw_operations );
/** PeerDist block download retrieval protocol interface operations */
static struct interface_operation peerblk_retrieval_operations[] = {
INTF_OP ( xfer_deliver, struct peerdist_block *, peerblk_retrieval_rx ),
INTF_OP ( intf_close, struct peerdist_block *, peerblk_retrieval_close),
};
/** PeerDist block download retrieval protocol interface descriptor */
static struct interface_descriptor peerblk_retrieval_desc =
INTF_DESC ( struct peerdist_block, retrieval,
peerblk_retrieval_operations );
/** PeerDist block download decryption process descriptor */
static struct process_descriptor peerblk_process_desc =
PROC_DESC ( struct peerdist_block, process, peerblk_decrypt );
/** PeerDist block download discovery operations */
static struct peerdisc_client_operations peerblk_discovery_operations = {
.discovered = peerblk_discovered,
};
/**
* Open PeerDist block download
*
* @v xfer Data transfer interface
* @v uri Original URI
* @v info Content information block
* @ret rc Return status code
*/
int peerblk_open ( struct interface *xfer, struct uri *uri,
struct peerdist_info_block *block ) {
const struct peerdist_info_segment *segment = block->segment;
const struct peerdist_info *info = segment->info;
struct digest_algorithm *digest = info->digest;
struct peerdist_block *peerblk;
unsigned long timeout;
size_t digestsize;
int rc;
/* Allocate and initialise structure */
peerblk = zalloc ( sizeof ( *peerblk ) + digest->ctxsize );
if ( ! peerblk ) {
rc = -ENOMEM;
goto err_alloc;
}
ref_init ( &peerblk->refcnt, peerblk_free );
intf_init ( &peerblk->xfer, &peerblk_xfer_desc, &peerblk->refcnt );
intf_init ( &peerblk->raw, &peerblk_raw_desc, &peerblk->refcnt );
intf_init ( &peerblk->retrieval, &peerblk_retrieval_desc,
&peerblk->refcnt );
peerblk->uri = uri_get ( uri );
memcpy ( &peerblk->range, &block->range, sizeof ( peerblk->range ) );
memcpy ( &peerblk->trim, &block->trim, sizeof ( peerblk->trim ) );
peerblk->offset = ( block->trim.start - info->trim.start );
peerblk->digest = info->digest;
peerblk->digestsize = digestsize = info->digestsize;
peerblk->digestctx = ( ( ( void * ) peerblk ) + sizeof ( *peerblk ) );
peerblk->segment = segment->index;
memcpy ( peerblk->id, segment->id, sizeof ( peerblk->id ) );
memcpy ( peerblk->secret, segment->secret, sizeof ( peerblk->secret ) );
peerblk->block = block->index;
memcpy ( peerblk->hash, block->hash, sizeof ( peerblk->hash ) );
xferbuf_malloc_init ( &peerblk->buffer );
process_init_stopped ( &peerblk->process, &peerblk_process_desc,
&peerblk->refcnt );
peerdisc_init ( &peerblk->discovery, &peerblk_discovery_operations );
INIT_LIST_HEAD ( &peerblk->queued );
timer_init ( &peerblk->timer, peerblk_expired, &peerblk->refcnt );
DBGC2 ( peerblk, "PEERBLK %p %d.%d id %02x%02x%02x%02x%02x..."
"%02x%02x%02x [%08zx,%08zx)", peerblk, peerblk->segment,
peerblk->block, peerblk->id[0], peerblk->id[1], peerblk->id[2],
peerblk->id[3], peerblk->id[4], peerblk->id[ digestsize - 3 ],
peerblk->id[ digestsize - 2 ], peerblk->id[ digestsize - 1 ],
peerblk->range.start, peerblk->range.end );
if ( ( peerblk->trim.start != peerblk->range.start ) ||
( peerblk->trim.end != peerblk->range.end ) ) {
DBGC2 ( peerblk, " covers [%08zx,%08zx)",
peerblk->trim.start, peerblk->trim.end );
}
DBGC2 ( peerblk, "\n" );
/* Open discovery */
if ( ( rc = peerdisc_open ( &peerblk->discovery, peerblk->id,
peerblk->digestsize ) ) != 0 )
goto err_open_discovery;
/* Schedule a retry attempt either immediately (if we already
* have some peers) or after the discovery timeout.
*/
timeout = ( list_empty ( &peerblk->discovery.segment->peers ) ?
( peerdisc_timeout_secs * TICKS_PER_SEC ) : 0 );
start_timer_fixed ( &peerblk->timer, timeout );
/* Record start time */
peerblk->started = peerblk_timestamp();
/* Attach to parent interface, mortalise self, and return */
intf_plug_plug ( xfer, &peerblk->xfer );
ref_put ( &peerblk->refcnt );
return 0;
err_open_discovery:
peerblk_close ( peerblk, rc );
err_alloc:
return rc;
}
