diff options
Diffstat (limited to 'qemu/roms/ipxe/src/net/pccrd.c')
| -rw-r--r-- | qemu/roms/ipxe/src/net/pccrd.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/net/pccrd.c b/qemu/roms/ipxe/src/net/pccrd.c new file mode 100644 index 000000000..04b5dd86c --- /dev/null +++ b/qemu/roms/ipxe/src/net/pccrd.c @@ -0,0 +1,286 @@ +/* + * 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 <stddef.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <ctype.h> +#include <errno.h> +#include <assert.h> +#include <ipxe/pccrd.h> + +/** @file + * + * Peer Content Caching and Retrieval: Discovery Protocol [MS-PCCRD] + * + * This protocol manages to ingeniously combine the excessive + * verbosity of XML with a paucity of actual information. For + * example: even in version 2.0 of the protocol it is still not + * possible to discover which peers hold a specific block within a + * given segment. + * + * For added bonus points, version 1.0 of the protocol is specified to + * use a case-sensitive string comparison (for SHA2 digest values) but + * nothing specifies whether the strings in question should be in + * upper or lower case. There are example strings given in the + * specification, but the author skilfully manages to leave the issue + * unresolved by using the somewhat implausible digest value of + * "0200000000000000000000000000000000000000000000000000000000000000". + * + * Just in case you were thinking that the silver lining of the choice + * to use an XML-based protocol would be the ability to generate and + * process messages with standard tools, version 2.0 of the protocol + * places most of the critical information inside a Base64-encoded + * custom binary data structure. Within an XML element, naturally. + * + * I hereby announce this specification to be the 2015 winner of the + * prestigious "UEFI HII API" award for incompetent design. + */ + +/** Discovery request format */ +#define PEERDIST_DISCOVERY_REQUEST \ + "<?xml version=\"1.0\" encoding=\"utf-8\"?>" \ + "<soap:Envelope " \ + "xmlns:soap=\"http://www.w3.org/2003/05/soap-envelope\" " \ + "xmlns:wsa=\"http://schemas.xmlsoap.org/ws/2004/08/addressing\" " \ + "xmlns:wsd=\"http://schemas.xmlsoap.org/ws/2005/04/discovery\" " \ + "xmlns:PeerDist=\"http://schemas.microsoft.com/p2p/" \ + "2007/09/PeerDistributionDiscovery\">" \ + "<soap:Header>" \ + "<wsa:To>" \ + "urn:schemas-xmlsoap-org:ws:2005:04:discovery" \ + "</wsa:To>" \ + "<wsa:Action>" \ + "http://schemas.xmlsoap.org/ws/2005/04/discovery/Probe" \ + "</wsa:Action>" \ + "<wsa:MessageID>" \ + "urn:uuid:%s" \ + "</wsa:MessageID>" \ + "</soap:Header>" \ + "<soap:Body>" \ + "<wsd:Probe>" \ + "<wsd:Types>" \ + "PeerDist:PeerDistData" \ + "</wsd:Types>" \ + "<wsd:Scopes MatchBy=\"http://schemas.xmlsoap.org/ws/" \ + "2005/04/discovery/strcmp0\">" \ + "%s" \ + "</wsd:Scopes>" \ + "</wsd:Probe>" \ + "</soap:Body>" \ + "</soap:Envelope>" + +/** + * Construct discovery request + * + * @v uuid Message UUID string + * @v id Segment identifier string + * @ret request Discovery request, or NULL on failure + * + * The request is dynamically allocated; the caller must eventually + * free() the request. + */ +char * peerdist_discovery_request ( const char *uuid, const char *id ) { + char *request; + int len; + + /* Construct request */ + len = asprintf ( &request, PEERDIST_DISCOVERY_REQUEST, uuid, id ); + if ( len < 0 ) + return NULL; + + return request; +} + +/** + * Locate discovery reply tag + * + * @v data Reply data (not NUL-terminated) + * @v len Length of reply data + * @v tag XML tag + * @ret found Found tag (or NULL if not found) + */ +static char * peerdist_discovery_reply_tag ( char *data, size_t len, + const char *tag ) { + size_t tag_len = strlen ( tag ); + + /* Search, allowing for the fact that the reply data is not + * cleanly NUL-terminated and may contain embedded NULs due to + * earlier parsing. + */ + for ( ; len >= tag_len ; data++, len-- ) { + if ( strncmp ( data, tag, tag_len ) == 0 ) + return data; + } + return NULL; +} + +/** + * Locate discovery reply values + * + * @v data Reply data (not NUL-terminated, will be modified) + * @v len Length of reply data + * @v name XML tag name + * @ret values Tag values (or NULL if not found) + * + * The reply data is modified by adding NULs and moving characters as + * needed to produce a NUL-separated list of values, terminated with a + * zero-length string. + * + * This is not supposed to be a full XML parser; it's supposed to + * include just enough functionality to allow PeerDist discovery to + * work with existing implementations. + */ +static char * peerdist_discovery_reply_values ( char *data, size_t len, + const char *name ) { + char buf[ 2 /* "</" */ + strlen ( name ) + 1 /* ">" */ + 1 /* NUL */ ]; + char *open; + char *close; + char *start; + char *end; + char *in; + char *out; + char c; + + /* Locate opening tag */ + snprintf ( buf, sizeof ( buf ), "<%s>", name ); + open = peerdist_discovery_reply_tag ( data, len, buf ); + if ( ! open ) + return NULL; + start = ( open + strlen ( buf ) ); + len -= ( start - data ); + data = start; + + /* Locate closing tag */ + snprintf ( buf, sizeof ( buf ), "</%s>", name ); + close = peerdist_discovery_reply_tag ( data, len, buf ); + if ( ! close ) + return NULL; + assert ( close >= open ); + end = close; + + /* Strip initial whitespace, convert other whitespace + * sequences to single NULs, add terminating pair of NULs. + * This will probably overwrite part of the closing tag. + */ + for ( in = start, out = start ; in < end ; in++ ) { + c = *in; + if ( isspace ( c ) ) { + if ( ( out > start ) && ( out[-1] != '\0' ) ) + *(out++) = '\0'; + } else { + *(out++) = c; + } + } + *(out++) = '\0'; + *(out++) = '\0'; + assert ( out < ( close + strlen ( buf ) ) ); + + return start; +} + +/** + * Parse discovery reply + * + * @v data Reply data (not NUL-terminated, will be modified) + * @v len Length of reply data + * @v reply Discovery reply to fill in + * @ret rc Return status code + * + * The discovery reply includes pointers to strings within the + * modified reply data. + */ +int peerdist_discovery_reply ( char *data, size_t len, + struct peerdist_discovery_reply *reply ) { + static const struct peerdist_discovery_block_count zcount = { + .hex = "00000000", + }; + struct peerdist_discovery_block_count *count; + unsigned int max; + unsigned int i; + char *scopes; + char *xaddrs; + char *blockcount; + char *in; + char *out; + size_t skip; + + /* Find <wsd:Scopes> tag */ + scopes = peerdist_discovery_reply_values ( data, len, "wsd:Scopes" ); + if ( ! scopes ) { + DBGC ( reply, "PCCRD %p missing <wsd:Scopes> tag\n", reply ); + return -ENOENT; + } + + /* Find <wsd:XAddrs> tag */ + xaddrs = peerdist_discovery_reply_values ( data, len, "wsd:XAddrs" ); + if ( ! xaddrs ) { + DBGC ( reply, "PCCRD %p missing <wsd:XAddrs> tag\n", reply ); + return -ENOENT; + } + + /* Find <PeerDist:BlockCount> tag */ + blockcount = peerdist_discovery_reply_values ( data, len, + "PeerDist:BlockCount" ); + if ( ! blockcount ) { + DBGC ( reply, "PCCRD %p missing <PeerDist:BlockCount> tag\n", + reply ); + return -ENOENT; + } + + /* Determine maximum number of segments (according to number + * of entries in the block count list). + */ + max = ( strlen ( blockcount ) / sizeof ( *count ) ); + count = container_of ( blockcount, + struct peerdist_discovery_block_count, hex[0] ); + + /* Eliminate any segments with a zero block count */ + for ( i = 0, in = scopes, out = scopes ; *in ; i++, in += skip ) { + + /* Fail if we have overrun the maximum number of segments */ + if ( i >= max ) { + DBGC ( reply, "PCCRD %p too many segment IDs\n", + reply ); + return -EPROTO; + } + + /* Delete segment if block count is zero */ + skip = ( strlen ( in ) + 1 /* NUL */ ); + if ( memcmp ( count[i].hex, zcount.hex, + sizeof ( zcount.hex ) ) == 0 ) + continue; + strcpy ( out, in ); + out += skip; + } + out[0] = '\0'; /* Ensure list is terminated with a zero-length string */ + + /* Fill in discovery reply */ + reply->ids = scopes; + reply->locations = xaddrs; + + return 0; +} |