-copied block-related functions from namestore to namecache

1 files changed, 738 insertions, 0 deletions

diff --git a/src/namecache/namecache_api.c b/src/namecache/namecache_api.c
new file mode 100644
index 000000000..a28ed7d53
--- /dev/null
+++ b/src/namecache/namecache_api.c
@@ -0,0 +1,738 @@
+/*
+     This file is part of GNUnet.
+     (C) 2010-2013 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 3, 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 namecache/namecache_api.c
+ * @brief API to access the NAMECACHE service
+ * @author Martin Schanzenbach
+ * @author Matthias Wachs
+ * @author Christian Grothoff
+ */
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_dnsparser_lib.h"
+#include "gnunet_arm_service.h"
+#include "gnunet_signatures.h"
+#include "gnunet_namecache_service.h"
+#include "gnunet_namestore_service.h"
+#include "namecache.h"
+
+
+#define LOG(kind,...) GNUNET_log_from (kind, "namecache-api",__VA_ARGS__)
+
+
+/**
+ * An QueueEntry used to store information for a pending
+ * NAMECACHE record operation
+ */
+struct GNUNET_NAMECACHE_QueueEntry
+{
+
+  /**
+   * Kept in a DLL.
+   */
+  struct GNUNET_NAMECACHE_QueueEntry *next;
+
+  /**
+   * Kept in a DLL.
+   */
+  struct GNUNET_NAMECACHE_QueueEntry *prev;
+
+  /**
+   * Main handle to access the namecache.
+   */
+  struct GNUNET_NAMECACHE_Handle *nsh;
+
+  /**
+   * Continuation to call
+   */
+  GNUNET_NAMECACHE_ContinuationWithStatus cont;
+
+  /**
+   * Closure for @e cont.
+   */
+  void *cont_cls;
+
+  /**
+   * Function to call with the blocks we get back; or NULL.
+   */
+  GNUNET_NAMESTORE_BlockProcessor block_proc;
+
+  /**
+   * Closure for @e block_proc.
+   */
+  void *block_proc_cls;
+
+  /**
+   * The operation id this zone iteration operation has
+   */
+  uint32_t op_id;
+
+};
+
+
+/**
+ * Message in linked list we should send to the service.  The
+ * actual binary message follows this struct.
+ */
+struct PendingMessage
+{
+
+  /**
+   * Kept in a DLL.
+   */
+  struct PendingMessage *next;
+
+  /**
+   * Kept in a DLL.
+   */
+  struct PendingMessage *prev;
+
+  /**
+   * Size of the message.
+   */
+  size_t size;
+
+};
+
+
+/**
+ * Connection to the NAMECACHE service.
+ */
+struct GNUNET_NAMECACHE_Handle
+{
+
+  /**
+   * Configuration to use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Socket (if available).
+   */
+  struct GNUNET_CLIENT_Connection *client;
+
+  /**
+   * Currently pending transmission request (or NULL).
+   */
+  struct GNUNET_CLIENT_TransmitHandle *th;
+
+  /**
+   * Head of linked list of pending messages to send to the service
+   */
+  struct PendingMessage *pending_head;
+
+  /**
+   * Tail of linked list of pending messages to send to the service
+   */
+  struct PendingMessage *pending_tail;
+
+  /**
+   * Head of pending namecache queue entries
+   */
+  struct GNUNET_NAMECACHE_QueueEntry *op_head;
+
+  /**
+   * Tail of pending namecache queue entries
+   */
+  struct GNUNET_NAMECACHE_QueueEntry *op_tail;
+
+  /**
+   * Reconnect task
+   */
+  GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
+
+  /**
+   * Delay introduced before we reconnect.
+   */
+  struct GNUNET_TIME_Relative reconnect_delay;
+
+  /**
+   * Should we reconnect to service due to some serious error?
+   */
+  int reconnect;
+
+  /**
+   * Did we start to receive yet?
+   */
+  int is_receiving;
+
+  /**
+   * The last operation id used for a NAMECACHE operation
+   */
+  uint32_t last_op_id_used;
+
+};
+
+
+/**
+ * Disconnect from service and then reconnect.
+ *
+ * @param h our handle
+ */
+static void
+force_reconnect (struct GNUNET_NAMECACHE_Handle *h);
+
+
+/**
+ * Handle an incoming message of type
+ * #GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE.
+ *
+ * @param qe the respective entry in the message queue
+ * @param msg the message we received
+ * @param size the message size
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error and we did NOT notify the client
+ */
+static int
+handle_lookup_block_response (struct GNUNET_NAMECACHE_QueueEntry *qe,
+                              const struct LookupBlockResponseMessage *msg,
+                              size_t size)
+{
+  struct GNUNET_NAMESTORE_Block *block;
+  char buf[size + sizeof (struct GNUNET_NAMESTORE_Block)
+           - sizeof (struct LookupBlockResponseMessage)];
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received `%s'\n",
+       "LOOKUP_BLOCK_RESPONSE");
+  if (0 == GNUNET_TIME_absolute_ntoh (msg->expire).abs_value_us)
+  {
+    /* no match found */
+    if (NULL != qe->block_proc)
+      qe->block_proc (qe->block_proc_cls, NULL);
+    return GNUNET_OK;
+  }
+
+  block = (struct GNUNET_NAMESTORE_Block *) buf;
+  block->signature = msg->signature;
+  block->derived_key = msg->derived_key;
+  block->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_GNS_RECORD_SIGN);
+  block->purpose.size = htonl (size - sizeof (struct LookupBlockResponseMessage) +
+                               sizeof (struct GNUNET_TIME_AbsoluteNBO) +
+                               sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose));
+  block->expiration_time = msg->expire;
+  memcpy (&block[1],
+          &msg[1],
+          size - sizeof (struct LookupBlockResponseMessage));
+  if (GNUNET_OK !=
+      GNUNET_NAMESTORE_block_verify (block))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  if (NULL != qe->block_proc)
+    qe->block_proc (qe->block_proc_cls, block);
+  else
+    GNUNET_break (0);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Handle an incoming message of type
+ * #GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE
+ *
+ * @param qe the respective entry in the message queue
+ * @param msg the message we received
+ * @param size the message size
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error and we did NOT notify the client
+ */
+static int
+handle_block_cache_response (struct GNUNET_NAMECACHE_QueueEntry *qe,
+                            const struct BlockCacheResponseMessage *msg,
+                            size_t size)
+{
+  int res;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received `%s'\n",
+       "BLOCK_CACHE_RESPONSE");
+  res = ntohl (msg->op_result);
+  /* TODO: add actual error message from namecache to response... */
+  if (NULL != qe->cont)
+    qe->cont (qe->cont_cls,
+              res,
+              (GNUNET_OK == res) ?
+              NULL
+              : _("Namecache failed to cache block"));
+  return GNUNET_OK;
+}
+
+
+/**
+ * Handle incoming messages for record operations
+ *
+ * @param qe the respective zone iteration handle
+ * @param msg the message we received
+ * @param type the message type in host byte order
+ * @param size the message size
+ * @return #GNUNET_OK on success, #GNUNET_NO if we notified the client about
+ *         the error, #GNUNET_SYSERR on error and we did NOT notify the client
+ */
+static int
+manage_record_operations (struct GNUNET_NAMECACHE_QueueEntry *qe,
+                          const struct GNUNET_MessageHeader *msg,
+                          uint16_t type,
+                          size_t size)
+{
+  /* handle different message type */
+  switch (type)
+  {
+  case GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE:
+    if (size < sizeof (struct LookupBlockResponseMessage))
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+    return handle_lookup_block_response (qe, (const struct LookupBlockResponseMessage *) msg, size);
+  case GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE:
+    if (size != sizeof (struct BlockCacheResponseMessage))
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+    return handle_block_cache_response (qe, (const struct BlockCacheResponseMessage *) msg, size);
+  default:
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * Type of a function to call when we receive a message
+ * from the service.
+ *
+ * @param cls the `struct GNUNET_NAMECACHE_SchedulingHandle`
+ * @param msg message received, NULL on timeout or fatal error
+ */
+static void
+process_namecache_message (void *cls,
+                           const struct GNUNET_MessageHeader *msg)
+{
+  struct GNUNET_NAMECACHE_Handle *h = cls;
+  const struct GNUNET_NAMECACHE_Header *gm;
+  struct GNUNET_NAMECACHE_QueueEntry *qe;
+  uint16_t size;
+  uint16_t type;
+  uint32_t r_id;
+  int ret;
+
+  if (NULL == msg)
+  {
+    force_reconnect (h);
+    return;
+  }
+  size = ntohs (msg->size);
+  type = ntohs (msg->type);
+  if (size < sizeof (struct GNUNET_NAMECACHE_Header))
+  {
+    GNUNET_break_op (0);
+    GNUNET_CLIENT_receive (h->client,
+                           &process_namecache_message, h,
+                           GNUNET_TIME_UNIT_FOREVER_REL);
+    return;
+  }
+  gm = (const struct GNUNET_NAMECACHE_Header *) msg;
+  r_id = ntohl (gm->r_id);
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received message type %u size %u op %u\n",
+       (unsigned int) type,
+       (unsigned int) size,
+       (unsigned int) r_id);
+
+  /* Is it a record related operation ? */
+  for (qe = h->op_head; qe != NULL; qe = qe->next)
+    if (qe->op_id == r_id)
+      break;
+  if (NULL != qe)
+  {
+    ret = manage_record_operations (qe, msg, type, size);
+    if (GNUNET_SYSERR == ret)
+    {
+      /* protocol error, need to reconnect */
+      h->reconnect = GNUNET_YES;
+    }
+    else
+    {
+      /* client was notified about success or failure, clean up 'qe' */
+      GNUNET_CONTAINER_DLL_remove (h->op_head,
+                                   h->op_tail,
+                                   qe);
+      GNUNET_free (qe);
+    }
+  }
+  if (GNUNET_YES == h->reconnect)
+  {
+    force_reconnect (h);
+    return;
+  }
+  GNUNET_CLIENT_receive (h->client, &process_namecache_message, h,
+                         GNUNET_TIME_UNIT_FOREVER_REL);
+}
+
+
+/**
+ * Transmit messages from the message queue to the service
+ * (if there are any, and if we are not already trying).
+ *
+ * @param h handle to use
+ */
+static void
+do_transmit (struct GNUNET_NAMECACHE_Handle *h);
+
+
+/**
+ * We can now transmit a message to NAMECACHE. Do it.
+ *
+ * @param cls the `struct GNUNET_NAMECACHE_Handle`
+ * @param size number of bytes we can transmit
+ * @param buf where to copy the messages
+ * @return number of bytes copied into @a buf
+ */
+static size_t
+transmit_message_to_namecache (void *cls,
+                               size_t size,
+                               void *buf)
+{
+  struct GNUNET_NAMECACHE_Handle *h = cls;
+  struct PendingMessage *p;
+  size_t ret;
+  char *cbuf;
+
+  h->th = NULL;
+  if ((0 == size) || (NULL == buf))
+  {
+    force_reconnect (h);
+    return 0;
+  }
+  ret = 0;
+  cbuf = buf;
+  while ( (NULL != (p = h->pending_head)) &&
+          (p->size <= size) )
+  {
+    memcpy (&cbuf[ret], &p[1], p->size);
+    ret += p->size;
+    size -= p->size;
+    GNUNET_CONTAINER_DLL_remove (h->pending_head,
+                                 h->pending_tail,
+                                 p);
+    if (GNUNET_NO == h->is_receiving)
+    {
+      h->is_receiving = GNUNET_YES;
+      GNUNET_CLIENT_receive (h->client,
+                             &process_namecache_message, h,
+                             GNUNET_TIME_UNIT_FOREVER_REL);
+    }
+    GNUNET_free (p);
+  }
+  do_transmit (h);
+  return ret;
+}
+
+
+/**
+ * Transmit messages from the message queue to the service
+ * (if there are any, and if we are not already trying).
+ *
+ * @param h handle to use
+ */
+static void
+do_transmit (struct GNUNET_NAMECACHE_Handle *h)
+{
+  struct PendingMessage *p;
+
+  if (NULL != h->th)
+    return; /* transmission request already pending */
+  if (NULL == (p = h->pending_head))
+    return; /* transmission queue empty */
+  if (NULL == h->client)
+    return;                     /* currently reconnecting */
+  h->th = GNUNET_CLIENT_notify_transmit_ready (h->client, p->size,
+                                               GNUNET_TIME_UNIT_FOREVER_REL,
+                                               GNUNET_NO, &transmit_message_to_namecache,
+                                               h);
+  GNUNET_break (NULL != h->th);
+}
+
+
+/**
+ * Reconnect to namecache service.
+ *
+ * @param h the handle to the NAMECACHE service
+ */
+static void
+reconnect (struct GNUNET_NAMECACHE_Handle *h)
+{
+  GNUNET_assert (NULL == h->client);
+  h->client = GNUNET_CLIENT_connect ("namecache", h->cfg);
+  GNUNET_assert (NULL != h->client);
+  do_transmit (h);
+}
+
+
+/**
+ * Re-establish the connection to the service.
+ *
+ * @param cls handle to use to re-connect.
+ * @param tc scheduler context
+ */
+static void
+reconnect_task (void *cls,
+                const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_NAMECACHE_Handle *h = cls;
+
+  h->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
+  reconnect (h);
+}
+
+
+/**
+ * Disconnect from service and then reconnect.
+ *
+ * @param h our handle
+ */
+static void
+force_reconnect (struct GNUNET_NAMECACHE_Handle *h)
+{
+  if (NULL != h->th)
+  {
+    GNUNET_CLIENT_notify_transmit_ready_cancel (h->th);
+    h->th = NULL;
+  }
+  h->reconnect = GNUNET_NO;
+  GNUNET_CLIENT_disconnect (h->client);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Reconnecting to namecache\n");
+  h->is_receiving = GNUNET_NO;
+  h->client = NULL;
+  h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
+  h->reconnect_task = GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
+                                                    &reconnect_task,
+                                                    h);
+}
+
+
+/**
+ * Get a fresh operation id to distinguish between namecache requests
+ *
+ * @param h the namecache handle
+ * @return next operation id to use
+ */
+static uint32_t
+get_op_id (struct GNUNET_NAMECACHE_Handle *h)
+{
+  return h->last_op_id_used++;
+}
+
+
+/**
+ * Initialize the connection with the NAMECACHE service.
+ *
+ * @param cfg configuration to use
+ * @return handle to the GNS service, or NULL on error
+ */
+struct GNUNET_NAMECACHE_Handle *
+GNUNET_NAMECACHE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_NAMECACHE_Handle *h;
+
+  h = GNUNET_new (struct GNUNET_NAMECACHE_Handle);
+  h->cfg = cfg;
+  h->reconnect_task = GNUNET_SCHEDULER_add_now (&reconnect_task, h);
+  h->last_op_id_used = 0;
+  return h;
+}
+
+
+/**
+ * Disconnect from the namecache service (and free associated
+ * resources).
+ *
+ * @param h handle to the namecache
+ */
+void
+GNUNET_NAMECACHE_disconnect (struct GNUNET_NAMECACHE_Handle *h)
+{
+  struct PendingMessage *p;
+  struct GNUNET_NAMECACHE_QueueEntry *q;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Cleaning up\n");
+  GNUNET_assert (NULL != h);
+  if (NULL != h->th)
+  {
+    GNUNET_CLIENT_notify_transmit_ready_cancel (h->th);
+    h->th = NULL;
+  }
+  while (NULL != (p = h->pending_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (h->pending_head, h->pending_tail, p);
+    GNUNET_free (p);
+  }
+  GNUNET_break (NULL == h->op_head);
+  while (NULL != (q = h->op_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (h->op_head, h->op_tail, q);
+    GNUNET_free (q);
+  }
+  if (NULL != h->client)
+  {
+    GNUNET_CLIENT_disconnect (h->client);
+    h->client = NULL;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != h->reconnect_task)
+  {
+    GNUNET_SCHEDULER_cancel (h->reconnect_task);
+    h->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  GNUNET_free (h);
+}
+
+
+/**
+ * Store an item in the namecache.  If the item is already present,
+ * it is replaced with the new record.
+ *
+ * @param h handle to the namecache
+ * @param block block to store
+ * @param cont continuation to call when done
+ * @param cont_cls closure for cont
+ * @return handle to abort the request
+ */
+struct GNUNET_NAMECACHE_QueueEntry *
+GNUNET_NAMECACHE_block_cache (struct GNUNET_NAMECACHE_Handle *h,
+                              const struct GNUNET_NAMESTORE_Block *block,
+                              GNUNET_NAMECACHE_ContinuationWithStatus cont,
+                              void *cont_cls)
+{
+  struct GNUNET_NAMECACHE_QueueEntry *qe;
+  struct PendingMessage *pe;
+  struct BlockCacheMessage *msg;
+  uint32_t rid;
+  size_t blen;
+  size_t msg_size;
+
+  GNUNET_assert (NULL != h);
+  blen = ntohl (block->purpose.size)
+    - sizeof (struct GNUNET_TIME_AbsoluteNBO)
+    - sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose);
+  rid = get_op_id (h);
+  qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
+  qe->nsh = h;
+  qe->cont = cont;
+  qe->cont_cls = cont_cls;
+  qe->op_id = rid;
+  GNUNET_CONTAINER_DLL_insert_tail (h->op_head, h->op_tail, qe);
+
+  /* setup msg */
+  msg_size = sizeof (struct BlockCacheMessage) + blen;
+  pe = GNUNET_malloc (sizeof (struct PendingMessage) + msg_size);
+  pe->size = msg_size;
+  msg = (struct BlockCacheMessage *) &pe[1];
+  msg->gns_header.header.type = htons (GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE);
+  msg->gns_header.header.size = htons (msg_size);
+  msg->gns_header.r_id = htonl (rid);
+  msg->expire = block->expiration_time;
+  msg->signature = block->signature;
+  msg->derived_key = block->derived_key;
+  memcpy (&msg[1], &block[1], blen);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Sending `%s' message with size %u and expiration %s\n",
+       "NAMECACHE_BLOCK_CACHE",
+       (unsigned int) msg_size,
+       GNUNET_STRINGS_absolute_time_to_string (GNUNET_TIME_absolute_ntoh (msg->expire)));
+  GNUNET_CONTAINER_DLL_insert_tail (h->pending_head, h->pending_tail, pe);
+  do_transmit (h);
+  return qe;
+}
+
+
+/**
+ * Get a result for a particular key from the namecache.  The processor
+ * will only be called once.
+ *
+ * @param h handle to the namecache
+ * @param derived_hash hash of zone key combined with name to lookup
+ * @param proc function to call on the matching block, or with
+ *        NULL if there is no matching block
+ * @param proc_cls closure for proc
+ * @return a handle that can be used to cancel
+ */
+struct GNUNET_NAMECACHE_QueueEntry *
+GNUNET_NAMECACHE_lookup_block (struct GNUNET_NAMECACHE_Handle *h,
+                               const struct GNUNET_HashCode *derived_hash,
+                               GNUNET_NAMESTORE_BlockProcessor proc, void *proc_cls)
+{
+  struct GNUNET_NAMECACHE_QueueEntry *qe;
+  struct PendingMessage *pe;
+  struct LookupBlockMessage *msg;
+  size_t msg_size;
+  uint32_t rid;
+
+  GNUNET_assert (NULL != h);
+  GNUNET_assert (NULL != derived_hash);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Looking for block under %s\n",
+       GNUNET_h2s (derived_hash));
+  rid = get_op_id(h);
+  qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
+  qe->nsh = h;
+  qe->block_proc = proc;
+  qe->block_proc_cls = proc_cls;
+  qe->op_id = rid;
+  GNUNET_CONTAINER_DLL_insert_tail (h->op_head, h->op_tail, qe);
+
+  msg_size = sizeof (struct LookupBlockMessage);
+  pe = GNUNET_malloc (sizeof (struct PendingMessage) + msg_size);
+  pe->size = msg_size;
+  msg = (struct LookupBlockMessage *) &pe[1];
+  msg->gns_header.header.type = htons (GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK);
+  msg->gns_header.header.size = htons (msg_size);
+  msg->gns_header.r_id = htonl (rid);
+  msg->query = *derived_hash;
+  GNUNET_CONTAINER_DLL_insert_tail (h->pending_head, h->pending_tail, pe);
+  do_transmit (h);
+  return qe;
+}
+
+
+/**
+ * Cancel a namecache operation.  The final callback from the
+ * operation must not have been done yet.
+ *
+ * @param qe operation to cancel
+ */
+void
+GNUNET_NAMECACHE_cancel (struct GNUNET_NAMECACHE_QueueEntry *qe)
+{
+  struct GNUNET_NAMECACHE_Handle *h = qe->nsh;
+
+  GNUNET_assert (NULL != qe);
+  GNUNET_CONTAINER_DLL_remove (h->op_head, h->op_tail, qe);
+  GNUNET_free(qe);
+}
+
+
+/* end of namecache_api.c */