From: Christian Grothoff <christian@grothoff.org>
Date: Sat, 24 Apr 2010 13:46:07 +0000 (+0000)
Subject: blocklib
X-Git-Tag: initial-import-from-subversion-38251~22013
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=8d9525a642c6bd74a2903ccb6358da8ebb081864;p=oweals%2Fgnunet.git

blocklib
---

diff --git a/src/block/Makefile.am b/src/block/Makefile.am
new file mode 100644
index 000000000..b9585c260
--- /dev/null
+++ b/src/block/Makefile.am
@@ -0,0 +1,28 @@
+INCLUDES = -I$(top_srcdir)/src/include
+
+if MINGW
+  WINFLAGS = -Wl,--no-undefined -Wl,--export-all-symbols
+endif
+
+if USE_COVERAGE
+  AM_CFLAGS = --coverage
+endif
+
+lib_LTLIBRARIES = libgnunetblock.la
+
+libgnunetblock_la_SOURCES = \
+  block.c 
+libgnunetblock_la_LIBADD = \
+ $(top_builddir)/src/util/libgnunetutil.la  
+
+check_PROGRAMS = \
+ test_block
+
+#TESTS = $(check_PROGRAMS)
+
+test_block_SOURCES = \
+ test_block.c
+test_block_LDADD = \
+ $(top_builddir)/src/block/libgnunetblock.la \
+ $(top_builddir)/src/util/libgnunetutil.la  
+
diff --git a/src/block/block.c b/src/block/block.c
new file mode 100644
index 000000000..24dab7907
--- /dev/null
+++ b/src/block/block.c
@@ -0,0 +1,230 @@
+/*
+     This file is part of GNUnet.
+     (C) 2010 Christian Grothoff (and other contributing authors)
+
+     GNUnet 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, or (at your
+     option) any later version.
+
+     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file block/block.c
+ * @brief library for data block manipulation
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_signatures.h"
+#include "gnunet_block_lib.h"
+
+/**
+ * Check if the given KBlock is well-formed.
+ *
+ * @param kb the kblock data (or at least "dsize" bytes claiming to be one)
+ * @param dsize size of "kb" in bytes; check for < sizeof(struct KBlock)!
+ * @param query where to store the query that this block answers
+ * @return GNUNET_OK if this is actually a well-formed KBlock
+ */
+static int
+check_kblock (const struct KBlock *kb,
+	      size_t dsize,
+	      GNUNET_HashCode *query)
+{
+  if (dsize < sizeof (struct KBlock))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (dsize - sizeof (struct KBlock) !=
+      ntohl (kb->purpose.size) 
+      - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) 
+      - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) ) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
+				&kb->purpose,
+				&kb->signature,
+				&kb->keyspace)) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (query != NULL)
+    GNUNET_CRYPTO_hash (&kb->keyspace,
+			sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+			query);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Check if the given NBlock is well-formed.
+ *
+ * @param nb the nblock data (or at least "dsize" bytes claiming to be one)
+ * @param dsize size of "nb" in bytes; check for < sizeof(struct NBlock)!
+ * @param query where to store the query that this block answers
+ * @return GNUNET_OK if this is actually a well-formed NBlock
+ */
+static int
+check_nblock (const struct NBlock *nb,
+	      size_t dsize,
+	      GNUNET_HashCode *query)
+{
+  if (dsize < sizeof (struct NBlock))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (dsize - sizeof (struct NBlock) !=
+      ntohl (nb->ns_purpose.size) 
+      - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) 
+      - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) ) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (dsize !=
+      ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
+				&nb->ksk_purpose,
+				&nb->ksk_signature,
+				&nb->keyspace)) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
+				&nb->ns_purpose,
+				&nb->ns_signature,
+				&nb->subspace)) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (query != NULL)
+    GNUNET_CRYPTO_hash (&nb->keyspace,
+			sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+			query);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Check if the given SBlock is well-formed.
+ *
+ * @param sb the sblock data (or at least "dsize" bytes claiming to be one)
+ * @param dsize size of "kb" in bytes; check for < sizeof(struct SBlock)!
+ * @param query where to store the query that this block answers
+ * @return GNUNET_OK if this is actually a well-formed SBlock
+ */
+static int
+check_sblock (const struct SBlock *sb,
+	      size_t dsize,
+	      GNUNET_HashCode *query)
+{
+  if (dsize < sizeof (struct SBlock))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (dsize !=
+      ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
+				&sb->purpose,
+				&sb->signature,
+				&sb->subspace)) 
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  if (query != NULL)
+    *query = sb->identifier;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Check if the given block is well-formed (and of the given type).
+ *
+ * @param type type of the block
+ * @param block the block data (or at least "size" bytes claiming to be one)
+ * @param size size of "kb" in bytes; check that it is large enough
+ * @param query where to store the query that this block answers
+ * @return GNUNET_OK if this is actually a well-formed block,
+ *         GNUNET_NO if we could not determine the query,
+ *         GNUNET_SYSERR if the block is malformed
+ */
+int
+GNUNET_BLOCK_check_block (enum GNUNET_BLOCK_Type type,
+			  const void *block,
+			  size_t size,
+			  GNUNET_HashCode *query)
+{
+  /* first, validate! */
+  switch (type)
+    {
+    case GNUNET_BLOCK_TYPE_DBLOCK:
+    case GNUNET_BLOCK_TYPE_IBLOCK:
+      GNUNET_CRYPTO_hash (block, size, query);
+      break;
+    case GNUNET_BLOCK_TYPE_KBLOCK:
+      if (GNUNET_OK !=
+	  check_kblock (block,
+			size,
+			query))
+	return GNUNET_SYSERR;
+      break;
+    case GNUNET_BLOCK_TYPE_SBLOCK:
+      if (GNUNET_OK !=
+	  check_sblock (block,
+			size,
+			query))
+	return GNUNET_SYSERR;
+      break;
+    case GNUNET_BLOCK_TYPE_NBLOCK:
+      if (GNUNET_OK !=
+	  check_nblock (block,
+			size,
+			query))
+	return GNUNET_SYSERR;
+      return GNUNET_OK;
+    case GNUNET_BLOCK_TYPE_ONDEMAND:
+      if (size != sizeof (struct OnDemandBlock))
+	return GNUNET_SYSERR;
+      memset (query, 0, sizeof (GNUNET_HashCode));      
+      return GNUNET_NO;
+    default:
+      /* unknown block type */
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  return GNUNET_OK;
+}
+
+
+/* end of block.c */
diff --git a/src/block/test_block b/src/block/test_block
new file mode 100755
index 000000000..2b533cc6b
--- /dev/null
+++ b/src/block/test_block
@@ -0,0 +1,148 @@
+#! /bin/sh
+
+# test_block - temporary wrapper script for .libs/test_block
+# Generated by ltmain.sh (GNU libtool) 2.2.6b Debian-2.2.6b-2
+#
+# The test_block program cannot be directly executed until all the libtool
+# libraries that it depends on are installed.
+#
+# This wrapper script should never be moved out of the build directory.
+# If it is, it will not operate correctly.
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+Xsed='/bin/sed -e 1s/^X//'
+sed_quote_subst='s/\([`"$\\]\)/\\\1/g'
+
+# Be Bourne compatible
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
+  emulate sh
+  NULLCMD=:
+  # Zsh 3.x and 4.x performs word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in *posix*) set -o posix;; esac
+fi
+BIN_SH=xpg4; export BIN_SH # for Tru64
+DUALCASE=1; export DUALCASE # for MKS sh
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+relink_command="(cd /home/grothoff/svn/gnunet/src/block; { test -z \"\${LIBRARY_PATH+set}\" || unset LIBRARY_PATH || { LIBRARY_PATH=; export LIBRARY_PATH; }; }; { test -z \"\${COMPILER_PATH+set}\" || unset COMPILER_PATH || { COMPILER_PATH=; export COMPILER_PATH; }; }; { test -z \"\${GCC_EXEC_PREFIX+set}\" || unset GCC_EXEC_PREFIX || { GCC_EXEC_PREFIX=; export GCC_EXEC_PREFIX; }; }; { test -z \"\${LD_RUN_PATH+set}\" || unset LD_RUN_PATH || { LD_RUN_PATH=; export LD_RUN_PATH; }; }; { test -z \"\${LD_LIBRARY_PATH+set}\" || unset LD_LIBRARY_PATH || { LD_LIBRARY_PATH=; export LD_LIBRARY_PATH; }; }; PATH=/home/grothoff/bin:/home/grothoff/private/software/prevent-linux-4.3.0/bin/:/home/grothoff/bin:/usr/local/bin:/usr/bin:/bin:/usr/games; export PATH; gcc -fno-strict-aliasing -Wall -g -O0 -o \$progdir/\$file test_block.o  -L/home/grothoff//lib ../../src/block/.libs/libgnunetblock.so ../../src/util/.libs/libgnunetutil.so -lm -ldl -Wl,-rpath -Wl,/home/grothoff/svn/gnunet/src/block/.libs -Wl,-rpath -Wl,/home/grothoff/svn/gnunet/src/util/.libs -Wl,-rpath -Wl,/home/grothoff/lib)"
+
+# This environment variable determines our operation mode.
+if test "$libtool_install_magic" = "%%%MAGIC variable%%%"; then
+  # install mode needs the following variables:
+  generated_by_libtool_version='2.2.6b'
+  notinst_deplibs=' ../../src/block/libgnunetblock.la ../../src/util/libgnunetutil.la'
+else
+  # When we are sourced in execute mode, $file and $ECHO are already set.
+  if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
+    ECHO="echo"
+    file="$0"
+    # Make sure echo works.
+    if test "X$1" = X--no-reexec; then
+      # Discard the --no-reexec flag, and continue.
+      shift
+    elif test "X`{ $ECHO '\t'; } 2>/dev/null`" = 'X\t'; then
+      # Yippee, $ECHO works!
+      :
+    else
+      # Restart under the correct shell, and then maybe $ECHO will work.
+      exec /bin/sh "$0" --no-reexec ${1+"$@"}
+    fi
+  fi
+
+  # Find the directory that this script lives in.
+  thisdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
+  test "x$thisdir" = "x$file" && thisdir=.
+
+  # Follow symbolic links until we get to the real thisdir.
+  file=`ls -ld "$file" | /bin/sed -n 's/.*-> //p'`
+  while test -n "$file"; do
+    destdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
+
+    # If there was a directory component, then change thisdir.
+    if test "x$destdir" != "x$file"; then
+      case "$destdir" in
+      [\\/]* | [A-Za-z]:[\\/]*) thisdir="$destdir" ;;
+      *) thisdir="$thisdir/$destdir" ;;
+      esac
+    fi
+
+    file=`$ECHO "X$file" | $Xsed -e 's%^.*/%%'`
+    file=`ls -ld "$thisdir/$file" | /bin/sed -n 's/.*-> //p'`
+  done
+
+
+  # Usually 'no', except on cygwin/mingw when embedded into
+  # the cwrapper.
+  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=no
+  if test "$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR" = "yes"; then
+    # special case for '.'
+    if test "$thisdir" = "."; then
+      thisdir=`pwd`
+    fi
+    # remove .libs from thisdir
+    case "$thisdir" in
+    *[\\/].libs ) thisdir=`$ECHO "X$thisdir" | $Xsed -e 's%[\\/][^\\/]*$%%'` ;;
+    .libs )   thisdir=. ;;
+    esac
+  fi
+
+  # Try to get the absolute directory name.
+  absdir=`cd "$thisdir" && pwd`
+  test -n "$absdir" && thisdir="$absdir"
+
+  program=lt-'test_block'
+  progdir="$thisdir/.libs"
+
+  if test ! -f "$progdir/$program" ||
+     { file=`ls -1dt "$progdir/$program" "$progdir/../$program" 2>/dev/null | /bin/sed 1q`; \
+       test "X$file" != "X$progdir/$program"; }; then
+
+    file="$$-$program"
+
+    if test ! -d "$progdir"; then
+      mkdir "$progdir"
+    else
+      rm -f "$progdir/$file"
+    fi
+
+    # relink executable if necessary
+    if test -n "$relink_command"; then
+      if relink_command_output=`eval $relink_command 2>&1`; then :
+      else
+	echo "$relink_command_output" >&2
+	rm -f "$progdir/$file"
+	exit 1
+      fi
+    fi
+
+    mv -f "$progdir/$file" "$progdir/$program" 2>/dev/null ||
+    { rm -f "$progdir/$program";
+      mv -f "$progdir/$file" "$progdir/$program"; }
+    rm -f "$progdir/$file"
+  fi
+
+  if test -f "$progdir/$program"; then
+    if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
+      # Run the actual program with our arguments.
+
+      exec "$progdir/$program" ${1+"$@"}
+
+      $ECHO "$0: cannot exec $program $*" 1>&2
+      exit 1
+    fi
+  else
+    # The program doesn't exist.
+    $ECHO "$0: error: \`$progdir/$program' does not exist" 1>&2
+    $ECHO "This script is just a wrapper for $program." 1>&2
+    echo "See the libtool documentation for more information." 1>&2
+    exit 1
+  fi
+fi
diff --git a/src/block/test_block.c b/src/block/test_block.c
new file mode 100644
index 000000000..b8586982a
--- /dev/null
+++ b/src/block/test_block.c
@@ -0,0 +1,36 @@
+/*
+     This file is part of GNUnet
+     (C) 2010 Christian Grothoff (and other contributing authors)
+
+     GNUnet 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, or (at your
+     option) any later version.
+
+     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+/**
+ * @file block/test_block.c
+ * @brief test for block.c
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_block_lib.h"
+
+#define DEBUG GNUNET_NO
+
+#define VERBOSE GNUNET_NO
+
+int
+main (int argc, char *argv[])
+{
+  return 0;                     /* testcase passed */
+}
diff --git a/src/include/gnunet_block_lib.h b/src/include/gnunet_block_lib.h
new file mode 100644
index 000000000..513605eb2
--- /dev/null
+++ b/src/include/gnunet_block_lib.h
@@ -0,0 +1,249 @@
+/*
+     This file is part of GNUnet.
+     (C) 2010 Christian Grothoff (and other contributing authors)
+
+     GNUnet 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, or (at your
+     option) any later version.
+
+     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file include/gnunet_block_lib.h
+ * @brief library for data block manipulation
+ * @author Christian Grothoff
+ */
+#ifndef GNUNET_BLOCK_LIB_H
+#define GNUNET_BLOCK_LIB_H
+
+#include "gnunet_util_lib.h"
+#ifdef __cplusplus
+extern "C"
+{
+#if 0                           /* keep Emacsens' auto-indent happy */
+}
+#endif
+#endif
+
+/**
+ * Blocks in the datastore and the datacache must have a unique type.
+ */
+enum GNUNET_BLOCK_Type 
+  {
+    /**
+     * Any type of block, used as a wildcard when searching.  Should
+     * never be attached to a specific block.
+     */
+    GNUNET_BLOCK_TYPE_ANY = 0,
+
+    /**
+     * Data block (leaf) in the CHK tree.
+     */
+    GNUNET_BLOCK_TYPE_DBLOCK = 1,
+
+    /**
+     * Inner block in the CHK tree.
+     */
+    GNUNET_BLOCK_TYPE_IBLOCK = 2,
+
+    /**
+     * Type of a block representing a keyword search result.
+     */
+    GNUNET_BLOCK_TYPE_KBLOCK = 3,
+
+    /**
+     * Type of a block that is used to advertise content in a namespace.
+     */
+    GNUNET_BLOCK_TYPE_SBLOCK = 4,
+
+    /**
+     * Type of a block representing a block to be encoded on demand from disk.
+     * Should never appear on the network directly.
+     */
+    GNUNET_BLOCK_TYPE_ONDEMAND = 5,
+
+    /**
+     * Type of a block that is used to advertise a namespace.  
+     */
+    GNUNET_BLOCK_TYPE_NBLOCK = 6
+
+  };
+
+
+
+
+
+/**
+ * @brief keyword block (advertising data under a keyword)
+ */
+struct KBlock
+{
+
+  /**
+   * GNUNET_RSA_Signature using RSA-key generated from search keyword.
+   */
+  struct GNUNET_CRYPTO_RsaSignature signature;
+
+  /**
+   * What is being signed and why?
+   */
+  struct GNUNET_CRYPTO_RsaSignaturePurpose purpose;
+
+  /**
+   * Key generated (!) from the H(keyword) as the seed!
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded keyspace;
+
+  /* 0-terminated URI here */
+
+  /* variable-size Meta-Data follows here */
+
+};
+
+/**
+ * @brief namespace content block (advertising data under an identifier in a namespace)
+ */
+struct SBlock
+{
+
+  /**
+   * GNUNET_RSA_Signature using RSA-key of the namespace
+   */
+  struct GNUNET_CRYPTO_RsaSignature signature;
+
+  /**
+   * What is being signed and why?
+   */
+  struct GNUNET_CRYPTO_RsaSignaturePurpose purpose;
+
+  /**
+   * Hash of the hash of the human-readable identifier used for
+   * this entry (the hash of the human-readable identifier is
+   * used as the key for decryption; the xor of this identifier
+   * and the hash of the "keyspace" is the datastore-query hash).
+   */
+  GNUNET_HashCode identifier;
+
+  /**
+   * Public key of the namespace.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded subspace;
+
+  /* 0-terminated update-identifier here */
+
+  /* 0-terminated URI here (except for NBlocks) */
+
+  /* variable-size Meta-Data follows here */
+
+};
+
+
+/**
+ * @brief namespace advertisement block (advertising root of a namespace)
+ */
+struct NBlock
+{
+
+  /**
+   * GNUNET_RSA_Signature using RSA-key generated from search keyword.
+   */
+  struct GNUNET_CRYPTO_RsaSignature ksk_signature;
+
+  /**
+   * What is being signed and why?
+   */
+  struct GNUNET_CRYPTO_RsaSignaturePurpose ksk_purpose;
+
+  /**
+   * Key generated (!) from the H(keyword) as the seed!
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded keyspace;
+
+  /**
+   * GNUNET_RSA_Signature using RSA-key of the namespace
+   */
+  struct GNUNET_CRYPTO_RsaSignature ns_signature;
+
+  /**
+   * What is being signed and why?
+   */
+  struct GNUNET_CRYPTO_RsaSignaturePurpose ns_purpose;
+
+  /**
+   * Public key of the namespace.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded subspace;
+
+  /* from here on, data is encrypted with H(keyword) */
+
+  /* 0-terminated root identifier here */
+
+  /* variable-size Meta-Data follows here */
+
+};
+
+
+
+
+/**
+ * @brief index block (indexing a DBlock that 
+ *        can be obtained directly from reading
+ *        the plaintext file)
+ */
+struct OnDemandBlock
+{
+  /**
+   * Hash code of the entire content of the
+   * file that was indexed (used to uniquely
+   * identify the plaintext file).
+   */
+  GNUNET_HashCode file_id;
+
+  /**
+   * At which offset should we be able to find
+   * this on-demand encoded block? (in NBO)
+   */
+  uint64_t offset GNUNET_PACKED;
+
+};
+
+
+/**
+ * Check if the given block is well-formed (and of the given type).
+ *
+ * @param type type of the block
+ * @param block the block data (or at least "size" bytes claiming to be one)
+ * @param size size of "kb" in bytes; check that it is large enough
+ * @param query where to store the query that this block answers
+ * @return GNUNET_OK if this is actually a well-formed KBlock
+ *         GNUNET_NO if we could not determine the query,
+ *         GNUNET_SYSERR if the block is malformed
+ */
+int
+GNUNET_BLOCK_check_block (enum GNUNET_BLOCK_Type type,
+			  const void *block,
+			  size_t size,
+			  GNUNET_HashCode *query);
+
+
+#if 0                           /* keep Emacsens' auto-indent happy */
+{
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+
+/* ifndef GNUNET_BLOCK_LIB_H */
+#endif
+/* end of gnunet_block_lib.h */