refactoring publishing code

1 files changed, 381 insertions, 0 deletions

diff --git a/src/fs/fs_tree.c b/src/fs/fs_tree.c
new file mode 100644
index 000000000..5d6a4f1d9
--- /dev/null
+++ b/src/fs/fs_tree.c
@@ -0,0 +1,381 @@
+/*
+     This file is part of GNUnet.
+     (C) 2009 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 fs/fs_tree.c
+ * @brief Merkle-tree-ish-CHK file encoding for GNUnet
+ * @see http://gnunet.org/encoding.php3
+ * @author Krista Bennett
+ * @author Christian Grothoff
+ *
+ * TODO:
+ * - decide if this API should be made public (gnunet_fs_service.h)
+ *   or remain "internal" (but with exported symbols?)
+ */
+#include "platform.h"
+#include "fs_tree.h"
+
+
+/**
+ * Context for an ECRS-based file encoder that computes
+ * the Merkle-ish-CHK tree.
+ */
+struct GNUNET_FS_TreeEncoder
+{
+
+  /**
+   * Global FS context.
+   */
+  struct GNUNET_FS_Handle *h;
+  
+  /**
+   * Closure for all callbacks.
+   */
+  void *cls;
+
+  /**
+   * Function to call on encrypted blocks.
+   */
+  GNUNET_FS_TreeBlockProcessor proc;
+
+  /**
+   * Function to call with progress information.
+   */
+  GNUNET_FS_TreeProgressCallback progress;
+
+  /**
+   * Function to call to receive input data.
+   */
+  GNUNET_FS_DataReader reader;
+
+  /**
+   * Function to call once we're done with processing.
+   */
+  GNUNET_SCHEDULER_Task cont;
+  
+  /**
+   * Set to an error message (if we had an error).
+   */
+  char *emsg;
+
+  /**
+   * Set to the URI (upon successful completion)
+   */
+  struct GNUNET_FS_Uri *uri;
+  
+  /**
+   * Overall file size.
+   */
+  uint64_t size;
+
+  /**
+   * How far are we?
+   */
+  uint64_t publish_offset;
+
+  /**
+   * How deep are we?
+   */
+  unsigned int current_depth;
+
+  /**
+   * How deep is the tree?
+   */
+  unsigned int chk_tree_depth;
+
+  /**
+   * In-memory cache of the current CHK tree.
+   * This struct will contain the CHK values
+   * from the root to the currently processed
+   * node in the tree as identified by 
+   * "current_depth" and "publish_offset".
+   * The "chktree" will be initially NULL,
+   * then allocated to a sufficient number of
+   * entries for the size of the file and
+   * finally freed once the upload is complete.
+   */
+  struct ContentHashKey *chk_tree;
+
+};
+
+
+/**
+ * Compute the depth of the CHK tree.
+ *
+ * @param flen file length for which to compute the depth
+ * @return depth of the tree
+ */
+static unsigned int
+compute_depth (uint64_t flen)
+{
+  unsigned int treeDepth;
+  uint64_t fl;
+
+  treeDepth = 1;
+  fl = DBLOCK_SIZE;
+  while (fl < flen)
+    {
+      treeDepth++;
+      if (fl * CHK_PER_INODE < fl)
+        {
+          /* integer overflow, this is a HUGE file... */
+          return treeDepth;
+        }
+      fl = fl * CHK_PER_INODE;
+    }
+  return treeDepth;
+}
+
+
+/**
+ * Initialize a tree encoder.  This function will call "proc" and
+ * "progress" on each block in the tree.  Once all blocks have been
+ * processed, "cont" will be scheduled.  The "reader" will be called
+ * to obtain the (plaintext) blocks for the file.  Note that this
+ * function will not actually call "proc".  The client must
+ * call "GNUNET_FS_tree_encoder_next" to trigger encryption (and
+ * calling of "proc") for the each block.
+ *
+ * @param h the global FS context
+ * @param size overall size of the file to encode
+ * @param cls closure for reader, proc, progress and cont
+ * @param reader function to call to read plaintext data
+ * @param proc function to call on each encrypted block
+ * @param progress function to call with progress information 
+ * @param cont function to call when done
+ */
+struct GNUNET_FS_TreeEncoder *
+GNUNET_FS_tree_encoder_create (struct GNUNET_FS_Handle *h,
+                               uint64_t size,
+                               void *cls,
+                               GNUNET_FS_DataReader reader,
+                               GNUNET_FS_TreeBlockProcessor proc,
+                               GNUNET_FS_TreeProgressCallback progress,
+                               GNUNET_SCHEDULER_Task cont)
+{
+  struct GNUNET_FS_TreeEncoder *te;
+  
+  te = GNUNET_malloc (sizeof (struct GNUNET_FS_TreeEncoder));
+  te->h = h;
+  te->size = size;
+  te->cls = cls;
+  te->reader = reader;
+  te->proc = proc;
+  te->progress = progress;
+  te->cont = cont;
+  te->chk_tree_depth = compute_depth (size);
+  te->current_depth = te->chk_tree_depth;
+  te->chk_tree = GNUNET_malloc (te->chk_tree_depth *
+                                CHK_PER_INODE *
+                                sizeof (struct ContentHashKey));
+  return te;
+}
+
+
+/**
+ * Compute the size of the current IBlock.
+ *
+ * @param height height of the IBlock in the tree (aka overall
+ *               number of tree levels minus depth); 0 == DBlock
+ * @param offset current offset in the overall file
+ * @return size of the corresponding IBlock
+ */
+static uint16_t 
+compute_iblock_size (unsigned int height,
+                     uint64_t offset)
+{
+  unsigned int ret;
+  unsigned int i;
+  uint64_t mod;
+  uint64_t bds;
+
+  GNUNET_assert (height > 0);
+  bds = DBLOCK_SIZE; /* number of bytes each CHK at level "i"
+                                  corresponds to */
+  for (i=0;i<height;i++)
+    bds *= CHK_PER_INODE;
+  mod = offset % bds;
+  if (0 == mod)
+    {
+      /* we were triggered at the end of a full block */
+      ret = CHK_PER_INODE;
+    }
+  else
+    {
+      /* we were triggered at the end of the file */
+      bds /= CHK_PER_INODE;
+      ret = mod / bds;
+      if (0 != mod % bds)
+        ret++; 
+    }
+  return (uint16_t) (ret * sizeof(struct ContentHashKey));
+}
+
+
+/**
+ * Compute the offset of the CHK for the
+ * current block in the IBlock above.
+ *
+ * @param height height of the IBlock in the tree (aka overall
+ *               number of tree levels minus depth); 0 == DBlock
+ * @param offset current offset in the overall file
+ * @return (array of CHKs') offset in the above IBlock
+ */
+static unsigned int
+compute_chk_offset (unsigned int height,
+                    uint64_t offset)
+{
+  uint64_t bds;
+  unsigned int ret;
+  unsigned int i;
+
+  bds = DBLOCK_SIZE; /* number of bytes each CHK at level "i"
+                                  corresponds to */
+  for (i=0;i<height;i++)
+    bds *= CHK_PER_INODE;
+  GNUNET_assert (0 == (offset % bds));
+  ret = offset / bds;
+  return ret % CHK_PER_INODE; 
+}
+
+
+/**
+ * Encrypt the next block of the file (and 
+ * call proc and progress accordingly; or 
+ * of course "cont" if we have already completed
+ * encoding of the entire file).
+ *
+ * @param te tree encoder to use
+ */
+void GNUNET_FS_tree_encoder_next (struct GNUNET_FS_TreeEncoder * te)
+{
+  struct ContentHashKey *mychk;
+  const void *pt_block;
+  uint16_t pt_size;
+  char iob[DBLOCK_SIZE];
+  char enc[DBLOCK_SIZE];
+  struct GNUNET_CRYPTO_AesSessionKey sk;
+  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  unsigned int off;
+
+  if (te->current_depth == te->chk_tree_depth)
+    {
+      pt_size = GNUNET_MIN(DBLOCK_SIZE,
+                           te->size - te->publish_offset);
+      if (pt_size !=
+          te->reader (te->cls,
+                      te->publish_offset,
+                      pt_size,
+                      iob,
+                      &te->emsg))
+        {
+          GNUNET_SCHEDULER_add_continuation (te->h->sched,
+                                             GNUNET_NO,
+                                             te->cont,
+                                             te->cls,
+                                             GNUNET_SCHEDULER_REASON_TIMEOUT);
+          return;
+        }
+      pt_block = iob;
+    }
+  else
+    {
+      pt_size = compute_iblock_size (te->chk_tree_depth - te->current_depth,
+                                     te->publish_offset); 
+      pt_block = &te->chk_tree[te->current_depth *
+                               CHK_PER_INODE];
+    }
+  off = compute_chk_offset (te->chk_tree_depth - te->current_depth,
+                            te->publish_offset);
+  mychk = &te->chk_tree[(te->current_depth-1)*CHK_PER_INODE+off];
+  GNUNET_CRYPTO_hash (pt_block, pt_size, &mychk->key);
+  GNUNET_CRYPTO_hash_to_aes_key (&mychk->key, &sk, &iv);
+  GNUNET_CRYPTO_aes_encrypt (pt_block,
+                             pt_size,
+                             &sk,
+                             &iv,
+                             enc);
+  if (NULL != te->proc)
+    te->proc (te->cls,
+              &mychk->query,
+              te->publish_offset,
+              pt_size,
+              enc,
+              (te->current_depth == te->chk_tree_depth) 
+              ? GNUNET_DATASTORE_BLOCKTYPE_DBLOCK 
+              : GNUNET_DATASTORE_BLOCKTYPE_IBLOCK);
+  if (NULL != te->progress)
+    te->progress (te->cls,
+                  te->publish_offset,
+                  pt_block,
+                  pt_size,
+                  te->current_depth);
+  GNUNET_CRYPTO_hash (enc, pt_size, &mychk->query);
+  if (te->current_depth == te->chk_tree_depth) 
+    { 
+      te->publish_offset += pt_size;
+      if ( (te->publish_offset == te->size) ||
+           (0 == te->publish_offset % (CHK_PER_INODE * DBLOCK_SIZE) ) )
+        te->current_depth--;
+    }
+  else
+    {
+      if ( (off == CHK_PER_INODE) ||
+           (te->publish_offset == te->size) )
+        te->current_depth--;
+      else
+        te->current_depth = te->chk_tree_depth;
+    }
+  if (0 == te->current_depth)
+    {
+      te->uri = GNUNET_malloc (sizeof(struct GNUNET_FS_Uri));
+      te->uri->type = chk;
+      te->uri->data.chk.chk = te->chk_tree[0];
+      te->uri->data.chk.file_length = te->size;
+      GNUNET_SCHEDULER_add_continuation (te->h->sched,
+                                         GNUNET_NO,
+                                         te->cont,
+                                         te->cls,
+                                         GNUNET_SCHEDULER_REASON_PREREQ_DONE);
+    }
+}
+
+
+/**
+ * Clean up a tree encoder and return information
+ * about the resulting URI or an error message.
+ * 
+ * @param te the tree encoder to clean up
+ * @param uri set to the resulting URI (if encoding finished)
+ * @param emsg set to an error message (if an error occured
+ *        within the tree encoder; if this function is called
+ *        prior to completion and prior to an internal error,
+ *        both "*uri" and "*emsg" will be set to NULL).
+ */
+void GNUNET_FS_tree_encoder_finish (struct GNUNET_FS_TreeEncoder * te,
+                                    struct GNUNET_FS_Uri **uri,
+                                    char **emsg)
+{
+  *uri = te->uri;
+  *emsg = te->emsg;
+  GNUNET_free (te->chk_tree);
+  GNUNET_free (te);
+}
+
+/* end of fs_tree.c */