[GNUnet-SVN] r16391 - gnunet/src/transport

[gnunet]

Author: grothoff
Date: 2011-08-05 16:19:42 +0200 (Fri, 05 Aug 2011)
New Revision: 16391

Modified:
   gnunet/src/transport/gnunet-service-transport_validation.c
   gnunet/src/transport/gnunet-service-transport_validation.h
Log:
stuff

Modified: gnunet/src/transport/gnunet-service-transport_validation.c
===================================================================
--- gnunet/src/transport/gnunet-service-transport_validation.c  2011-08-05 
11:06:30 UTC (rev 16390)
+++ gnunet/src/transport/gnunet-service-transport_validation.c  2011-08-05 
14:19:42 UTC (rev 16391)
@@ -25,27 +25,351 @@
  */
 #include "platform.h"
 #include "gnunet-service-transport_validation.h"
+#include "gnunet-service-transport.h"
+#include "gnunet_hello_lib.h"
+#include "gnunet_peerinfo_service.h"
 
+/**
+ * How long until a HELLO verification attempt should time out?
+ * Must be rather small, otherwise a partially successful HELLO
+ * validation (some addresses working) might not be available
+ * before a client's request for a connection fails for good.
+ * Besides, if a single request to an address takes a long time,
+ * then the peer is unlikely worthwhile anyway.
+ */
+#define HELLO_VERIFICATION_TIMEOUT GNUNET_TIME_relative_multiply 
(GNUNET_TIME_UNIT_SECONDS, 15)
 
 /**
+ * How long is a PONG signature valid?  We'll recycle a signature until
+ * 1/4 of this time is remaining.  PONGs should expire so that if our
+ * external addresses change an adversary cannot replay them indefinitely.
+ * OTOH, we don't want to spend too much time generating PONG signatures,
+ * so they must have some lifetime to reduce our CPU usage.
+ */
+#define PONG_SIGNATURE_LIFETIME GNUNET_TIME_relative_multiply 
(GNUNET_TIME_UNIT_HOURS, 1)
+
+/**
+ * After how long do we expire an address in a HELLO that we just
+ * validated?  This value is also used for our own addresses when we
+ * create a HELLO.
+ */
+#define HELLO_ADDRESS_EXPIRATION GNUNET_TIME_relative_multiply 
(GNUNET_TIME_UNIT_HOURS, 12)
+
+
+/**
+ * How long before an existing address expires should we again try to
+ * validate it?  Must be (significantly) smaller than
+ * HELLO_ADDRESS_EXPIRATION.
+ */
+#define HELLO_REVALIDATION_START_TIME GNUNET_TIME_relative_multiply 
(GNUNET_TIME_UNIT_HOURS, 1)
+
+/**
+ * Size of the validation map hashmap.
+ */
+#define VALIDATION_MAP_SIZE 256
+
+
+/**
+ * Information about an address under validation
+ */
+struct ValidationEntry 
+{
+
+  /**
+   * Name of the transport.
+   */
+  char *transport_name;
+
+  /**
+   * The address, actually a pointer to the end
+   * of this struct.  Do not free!
+   */
+  const void *addr;
+
+  /**
+   * The identity of the peer.
+   */
+  struct GNUNET_PeerIdentity pid;
+
+  /**
+   * ID of task that will clean up this entry if nothing happens.
+   */
+  GNUNET_SCHEDULER_TaskIdentifier timeout_task;
+
+  /**
+   * At what time did we send the latest validation request?
+   */
+  struct GNUNET_TIME_Absolute send_time;
+
+  /**
+   * When did we last succeed with validating this address?
+   * FOREVER if the address has not been validated (we're currently checking)
+   * ZERO if the address was validated a long time ago (from PEERINFO)
+   * otherwise a time in the past if this process validated the address
+   */
+  struct GNUNET_TIME_Absolute last_validated_at;
+
+  /**
+   * How long until we can try to validate this address again?
+   * FOREVER if the address is for an unsupported plugin (from PEERINFO)
+   * ZERO if the address is considered valid (no validation needed)
+   * otherwise a time in the future if we're currently denying re-validation
+   */
+  struct GNUNET_TIME_Absolute validation_block;
+                                           
+  /**
+   * Challenge number we used.
+   */
+  uint32_t challenge;
+
+  /**
+   * Length of addr.
+   */
+  size_t addrlen;
+
+};
+
+
+/**
+ * Context of currently active requests to peerinfo
+ * for validation of HELLOs.
+ */
+struct CheckHelloValidatedContext
+{
+
+  /**
+   * This is a doubly-linked list.
+   */
+  struct CheckHelloValidatedContext *next;
+
+  /**
+   * This is a doubly-linked list.
+   */
+  struct CheckHelloValidatedContext *prev;
+
+  /**
+   * Hello that we are validating.
+   */
+  const struct GNUNET_HELLO_Message *hello;
+
+  /**
+   * Context for peerinfo iteration.
+   */
+  struct GNUNET_PEERINFO_IteratorContext *piter;
+
+};
+
+
+/**
+ * Head of linked list of HELLOs awaiting validation.
+ */
+static struct CheckHelloValidatedContext *chvc_head;
+
+/**
+ * Tail of linked list of HELLOs awaiting validation
+ */
+static struct CheckHelloValidatedContext *chvc_tail;
+
+/**
+ * Map of PeerIdentities to 'struct ValidationEntry*'s (addresses
+ * of the given peer that we are currently validating, have validated
+ * or are blocked from re-validation for a while).
+ */
+static struct GNUNET_CONTAINER_MultiHashMap *validation_map;
+
+
+/**
  * Start the validation subsystem.
  */
 void 
 GST_validation_start ()
 {
+  validation_map = GNUNET_CONTAINER_multihashmap_create (VALIDATION_MAP_SIZE);
 }
 
 
 /**
+ * Iterate over validation entries and free them.
+ *
+ * @param cls (unused)
+ * @param key peer identity (unused)
+ * @param value a 'struct ValidationEntry' to clean up
+ * @return GNUNET_YES (continue to iterate)
+ */
+static int
+cleanup_validation_entry (void *cls,
+                         const GNUNET_HashCode *key,
+                         void *value)
+{
+  struct ValidationEntry *ve = value;
+    
+  GNUNET_free (ve->transport_name);
+  if (GNUNET_SCHEDULER_NO_TASK != ve->timeout_task)
+    {
+      GNUNET_SCHEDULER_cancel (ve->timeout_task);
+      ve->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+  GNUNET_free (ve);
+  return GNUNET_OK;
+}
+
+
+/**
  * Stop the validation subsystem.
  */
 void
 GST_validation_stop ()
 {
+  struct CheckHelloValidatedContext *chvc;
+
+  GNUNET_CONTAINER_multihashmap_iterate (validation_map,
+                                        &cleanup_validation_entry,
+                                        NULL);
+  GNUNET_CONTAINER_multihashmap_destroy (validation_map);
+  validation_map = NULL;
+  while (NULL != (chvc = chvc_head))
+    {
+      GNUNET_CONTAINER_DLL_remove (chvc_head,
+                                  chvc_tail,
+                                  chvc);
+      GNUNET_PEERINFO_iterate_cancel (chvc->piter);      
+      GNUNET_free (chvc);
+    }
 }
 
 
+#if 0
 /**
+ * Address validation cleanup task (record no longer needed).
+ *
+ * @param cls the 'struct ValidationEntry'
+ * @param tc scheduler context (unused)
+ */
+static void
+timeout_hello_validation (void *cls, 
+                         const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct ValidationEntry *va = cls;
+
+  va->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  GNUNET_STATISTICS_update (GST_stats,
+                           gettext_noop ("# address records discarded"),
+                           1,
+                           GNUNET_NO);
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CONTAINER_multihashmap_remove (validation_map,
+                                                     &va->pid.hashPubKey,
+                                                     va));
+  GNUNET_free (va->transport_name);
+  GNUNET_free (va);
+}
+#endif
+
+
+/**
+ * Context for the validation entry match function.
+ */
+struct ValidationEntryMatchContext
+{
+  /**
+   * Where to store the result?
+   */
+  struct ValidationEntry *ve;
+  
+  /**
+   * Transport name we're looking for.
+   */
+  const char *transport_name;
+
+  /**
+   * Address we're interested in.
+   */
+  const char *addr;
+
+  /**
+   * Number of bytes in 'addr'.
+   */
+  size_t addrlen;
+};
+
+
+/**
+ * Iterate over validation entries until a matching one is found.
+ *
+ * @param cls the 'struct ValidationEntryMatchContext'
+ * @param key peer identity (unused)
+ * @param value a 'struct ValidationEntry' to match
+ * @return GNUNET_YES if the entry does not match,
+ *         GNUNET_NO if the entry does match
+ */
+static int
+validation_entry_match (void *cls,
+                       const GNUNET_HashCode *key,
+                       void *value)
+{
+  struct ValidationEntryMatchContext *vemc = cls;
+  struct ValidationEntry *ve = value;
+
+  if ( (ve->addrlen == vemc->addrlen) &&
+       (0 == memcmp (ve->addr, vemc->addr, ve->addrlen)) &&
+       (0 == strcmp (ve->transport_name, vemc->transport_name)) )
+    {
+      vemc->ve = ve;
+      return GNUNET_NO;
+    }
+  return GNUNET_YES;
+}
+
+
+/**
+ * Find a ValidationEntry entry for the given neighbour that matches
+ * the given address and transport.  If none exists, create one (but
+ * without starting any validation).
+ *
+ * @param neighbour which peer we care about
+ * @param tname name of the transport plugin
+ * @param session session to look for, NULL for 'any'; otherwise
+ *        can be used for the service to "learn" this session ID
+ *        if 'addr' matches
+ * @param addr binary address
+ * @param addrlen length of addr
+ * @return validation entry matching the given specifications
+ */
+static struct ValidationEntry *
+find_validation_entry (struct GNUNET_PeerIdentity *neighbour,
+                      const char *tname,
+                      const char *addr,
+                      size_t addrlen)
+{
+  struct ValidationEntryMatchContext vemc;
+  struct ValidationEntry *ve;
+
+  vemc.ve = NULL;
+  vemc.transport_name = tname;
+  vemc.addr = addr;
+  vemc.addrlen = addrlen;
+  GNUNET_CONTAINER_multihashmap_get_multiple (validation_map,
+                                             &neighbour->hashPubKey,
+                                             &validation_entry_match,
+                                             &vemc);
+  if (NULL != (ve = vemc.ve))
+    return ve;
+  ve = GNUNET_malloc (sizeof (struct ValidationEntry) + addrlen);
+  ve->transport_name = GNUNET_strdup (tname);
+  ve->addr = (void*) &ve[1];
+  ve->pid = *neighbour;
+  memcpy (&ve[1], addr, addrlen);
+  ve->addrlen = addrlen;
+  ve->last_validated_at = GNUNET_TIME_UNIT_FOREVER_ABS;
+  GNUNET_CONTAINER_multihashmap_put (validation_map,
+                                    &neighbour->hashPubKey,
+                                    ve,
+                                    
GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
+  return ve;
+}
+
+
+/**
  * We've received a PING.  If appropriate, generate a PONG.
  *
  * @param sender peer sending the PING
@@ -87,6 +411,37 @@
 
 
 /**
+ * Iterator callback to go over all addresses and try to validate them
+ * (unless blocked or already validated).
+ *
+ * @param cls pointer to the 'struct PeerIdentity' of the peer
+ * @param tname name of the transport
+ * @param expiration expiration time
+ * @param addr the address
+ * @param addrlen length of the address
+ * @return GNUNET_OK (keep the address)
+ */
+static int
+validate_address (void *cls,
+                 const char *tname,
+                 struct GNUNET_TIME_Absolute expiration,
+                 const void *addr, 
+                 uint16_t addrlen)
+{
+  struct GNUNET_PeerIdentity *pid = cls;
+  struct ValidationEntry *ve;
+  
+  if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value == 0)
+    return GNUNET_OK; /* expired */
+  ve = find_validation_entry (pid, tname, addr, addrlen);
+  // FIXME: check if validated/blocked, if not start validation...
+  ve++; // make compiler happy
+  return GNUNET_OK;
+}
+
+
+
+/**
  * We've received a HELLO, check which addresses are new and trigger
  * validation.
  *
@@ -95,6 +450,21 @@
 void
 GST_validation_handle_hello (const struct GNUNET_MessageHeader *hello)
 {
+  const struct GNUNET_HELLO_Message* hm = (const struct GNUNET_HELLO_Message*) 
hello;
+  struct GNUNET_PeerIdentity pid;
+
+  if (GNUNET_OK !=
+      GNUNET_HELLO_get_id (hm, &pid))    
+    {
+      /* malformed HELLO */
+      GNUNET_break (0);
+      return; 
+    }
+  GNUNET_assert (NULL ==
+                GNUNET_HELLO_iterate_addresses (hm,
+                                                GNUNET_NO,
+                                                &validate_address,
+                                                &pid));
 }
 
 
@@ -103,10 +473,46 @@
  */
 struct GST_ValidationIteratorContext
 {
+  /**
+   * Function to call on each address.
+   */
+  GST_ValidationAddressCallback cb;
+
+  /**
+   * Closure for 'cb'.
+   */
+  void *cb_cls;
 };
 
 
 /**
+ * Call the callback in the closure for each validation entry.
+ *
+ * @param cls the 'struct GST_ValidationIteratorContext'
+ * @param key the peer's identity
+ * @param value the 'struct ValidationEntry'
+ * @return GNUNET_OK (continue to iterate)
+ */
+static int
+iterate_addresses (void *cls,
+                  const GNUNET_HashCode *key,
+                  void *value)
+{
+  struct GST_ValidationIteratorContext *vic = cls;
+  struct ValidationEntry *ve = value;
+
+  vic->cb (vic->cb_cls,
+          &ve->pid,
+          ve->last_validated_at,
+          ve->validation_block,
+          ve->transport_name,
+          ve->addr,
+          ve->addrlen);
+  return GNUNET_OK;
+}
+
+
+/**
  * Call the given function for each address for the given target.
  * Can either give a snapshot (synchronous API) or be continuous.
  *
@@ -124,7 +530,22 @@
                              GST_ValidationAddressCallback cb,
                              void *cb_cls)
 {
-  return NULL;
+  struct GST_ValidationIteratorContext *vic;
+
+  vic = GNUNET_malloc (sizeof (struct GST_ValidationIteratorContext));
+  vic->cb = cb;
+  vic->cb_cls = cb_cls;
+  GNUNET_CONTAINER_multihashmap_get_multiple (validation_map,
+                                             &target->hashPubKey,
+                                             &iterate_addresses,
+                                             vic);
+  if (GNUNET_YES == snapshot_only)
+    {
+      GNUNET_free (vic);
+      return NULL;
+    }
+  /* FIXME: install 'vic' somewhere */
+  return vic;
 }
 
 
@@ -136,7 +557,8 @@
 void
 GST_validation_get_addresses_cancel (struct GST_ValidationIteratorContext *ctx)
 {
-  GNUNET_break (0);
+  /* FIXME: remove 'vic' from DS */
+  GNUNET_free (ctx);
 }
 
 

Modified: gnunet/src/transport/gnunet-service-transport_validation.h
===================================================================
--- gnunet/src/transport/gnunet-service-transport_validation.h  2011-08-05 
11:06:30 UTC (rev 16390)
+++ gnunet/src/transport/gnunet-service-transport_validation.h  2011-08-05 
14:19:42 UTC (rev 16391)
@@ -105,10 +105,10 @@
  * @param target peer this change is about, never NULL
  * @param last_validated_at is FOREVER if the address has not been validated 
(we're currently checking)
  *                          is ZERO if the address was validated a long time 
ago (from PEERINFO)
- *                          is a time in the past if this process validated 
the address
+ *                          otherwise a time in the past if this process 
validated the address
  * @param validation_block  is FOREVER if the address is for an unsupported 
plugin (from PEERINFO)
  *                          is ZERO if the address is considered valid (no 
validation needed)
- *                          is a time in the future if we're currently denying 
re-validation
+ *                          otherwise a time in the future if we're currently 
denying re-validation
  * @param plugin_name name of the plugin
  * @param plugin_address binary address
  * @param plugin_address_len length of address