some documentation

1 files changed, 256 insertions, 15 deletions

diff --git a/src/ats/gnunet-service-ats_addresses.h b/src/ats/gnunet-service-ats_addresses.h
index ddb011fce..82d42a6b1 100644
--- a/src/ats/gnunet-service-ats_addresses.h
+++ b/src/ats/gnunet-service-ats_addresses.h
@@ -32,6 +32,198 @@
 #include "gnunet_statistics_service.h"
 #include "ats.h"
 
+/**
+ * NOTE: Do not change this documentation. This documentation is based on
+ * gnunet.org:/vcs/fsnsg/ats-paper.git/tech-doku/ats-tech-guide.tex
+ * use build_txt.sh to generate plaintext output
+ *
+ *   1 ATS addresses : ATS address management
+ *
+ *    This ATS addresses ("addresses") component manages the addresses known to
+ *    ATS service and suggests addresses to transport service when it is
+ *    interested in address suggestion for a peer. ATS addresses also
+ *    instantiates the bandwidth assignment mechanism (solver), notifies it
+ *    about changes to addresses and forwards changes to bandwidth assignments
+ *    to transport, depending if transport is interested in this change.
+ *
+ *     1.1 Input data
+ *
+ *       1.1.1 Addresses
+ *
+ *    Addresses are added by specifying peer ID, plugin, address, address length
+ *    and session, if available. ATS information can be specified if available.
+ *
+ *       1.1.2 Networks
+ *
+ *    ATS specifies a fix set of networks an address can belong to. For each
+ *    network an inbound and outbound quota will be specified. The available
+ *    networks and addtional helper varaibles are defined in
+ *    gnunet_ats_service.h. At the moment 5 networks are defined:
+ *      * GNUNET_ATS_NET_UNSPECIFIED
+ *      * GNUNET_ATS_NET_LOOPBACK
+ *      * GNUNET_ATS_NET_LAN
+ *      * GNUNET_ATS_NET_WAN
+ *      * GNUNET_ATS_NET_WLAN
+ *
+ *    The total number of networks defined is stored in
+ *    GNUNET_ATS_NetworkTypeCount GNUNET_ATS_NetworkType can be used array
+ *    initializer for an int array, while GNUNET_ATS_NetworkType is an
+ *    initializer for a char array containing a string description of all
+ *    networks
+ *
+ *       1.1.3 Quotas
+ *
+ *    An inbound and outbound quota for each of the networks mentioned in 1.1.2
+ *    is loaded from ats configuration during initialization. This quota defines
+ *    to total amount of inbound and outbound traffic allowed for a specific
+ *    network. The configuration values used are in section ats:
+ *      * "NETWORK"_QUOTA_IN = <value>
+ *      * "NETWORK"_QUOTA_IN = <value>
+ *
+ *    You can specify quotas by setting the <value> to a:
+ *      * unrestricted: unlimited
+ *      * number of bytes: e.g. 10240
+ *      * fancy value: e.g. 64 Kib
+ *
+ *    unlimited is defined as GNUNET_ATS_MaxBandwidthString and equivalent to
+ *    the value GNUNET_ATS_MaxBandwidth Important predefined values for quotas
+ *    are:
+ *      * GNUNET_ATS_DefaultBandwidth: 65536
+ *      * GNUNET_ATS_MaxBandwidth: UINT32_MAX
+ *      * GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT: 1024
+ *
+ *    Details of loading quotas and default values will be described on
+ *
+ *       1.1.4 Preference values
+ *
+ *     1.2 Data structures used
+ *
+ *    Addresse uses struct ATS_Address for each address. The structs are stored
+ *    in a linked list and provides a pointer void *solver_information for the
+ *    solver to store address specific information. It provides the int values
+ *    active which is set to GNUNET_YES if the address is select for transport
+ *    use and used, representing that transport service is actively using this
+ *    address. Address information are stored in peer, addr, addr_len, plugin.
+ *
+ *     1.3 Initialization
+ *
+ *    During initialization a hashmap to store addresses is created. The quotas
+ *    for all networks defined for ATS are loaded from configuration. For each
+ *    network first the logic will check if the string
+ *    GNUNET_ATS_MaxBandwidthString is configured, if not it will try to convert
+ *    the configured value as a fancy size and if this fails it will try to use
+ *    it as a value_number. If no configuration value is found it will assign
+ *    GNUNET_ATS_DefaultBandwidth. The most important step is to load the
+ *    configured solver using configuration "[ats]:MODE". Current solvers are
+ *    MODE_SIMPLISTIC, MODE_MLP. Interaction is done using a solver API
+ *
+ *     1.4 Solver API
+ *
+ *    Solver functions:
+ *      * s_init: init the solver with required information
+ *      * s_add: add a new address
+ *      * s_update: update ATS values or session for an address
+ *      * s_get: get prefered address for a peer
+ *      * s_del: delete an address
+ *      * s_pref: change preference value for a peer
+ *      * s_done: shutdown solver
+ *
+ *    Callbacks: addresses provides a bandwidth_changed_cb callback to the
+ *    solver which is called when bandwidth assigned to peer has changed
+ *
+ *     1.5 Shutdown
+ *
+ *    During shutdown all addresses are freed and the solver told to shutdown
+ *
+ *     1.6 Addresses and sessions
+ *
+ *    Addresses consist of the address itself and a numerical session. When a
+ *    new address without a session is added it has no session, so it gets
+ *    session 0 assigned. When an address with a session is added and an address
+ *    object with session 0 is found, this object is updated with the session
+ *    otherwise a new address object with this session assigned is created.
+ *
+ *       1.6.1 Terminology
+ *
+ *    Addresses a1,a2 with session s1, s2 are "exact" if:
+ *    (a1 == a2)&&(s1 == s2)
+ *    Addresses a1,a2 with session s1, s2 are "equivalent" if:
+ *    (a1 == a2)&&((s1 == s2)||(s1 == 0)||(s2 == 0)
+ *
+ *     1.7 Address management
+ *
+ *    Transport service notifies ATS about changes to the addresses known to
+ *    him.
+ *
+ *       1.7.1 Adding an address
+ *
+ *    When transport learns a new address it tells ATS and ATS is telling
+ *    addresses about it using GAS_address_add. If not known to addresses it
+ *    creates a new address object and calls solver's s_add. ATS information are
+ *    deserialized and solver is notified about the session and ATS information
+ *    using s_update.
+ *
+ *       1.7.2 Updating an address
+ *
+ *    Addresses does an lookup up for the existing address with the given
+ *    session. If disassembles included ATS information and notifies the solver
+ *    using s_update about the update.
+ *
+ *       1.7.3 Deleting an address
+ *
+ *    Addresses does an lookup for the exact address and session and if removes
+ *    this address. If session != 0 the session is set to 0 and the address is
+ *    kept. If session == 0, the addresses is removed.
+ *
+ *       1.7.4 Requesting an address suggestion
+ *
+ *    The address client issues a request address message to be notified about
+ *    address suggestions for a specific peer. Addresses asks the solver with
+ *    s_get. If no address is available, it will not send a response, otherwise
+ *    it will respond with the choosen address.
+ *
+ *       1.7.5 Address suggestions
+ *
+ *    Addresses will notify the client automatically on any bandwidth_changed_cb
+ *    by the solver if a address suggestion request is pending. If no address is
+ *    available it will not respond at all If the client is not interested
+ *    anymore, it has to cancel the address suggestion request.
+ *
+ *       1.7.6 Suggestions blocks and reset
+ *
+ *    After suggesting an address it is blocked for ATS_BLOCKING_DELTA sec. to
+ *    prevent the client from being thrashed. If the client requires immediately
+ *    it can reset this block using GAS_addresses_handle_backoff_reset.
+ *
+ *       1.7.7 Marking address in use
+ *
+ *    The client can notify addresses that it successfully uses an address and
+ *    wants this address to be kept by calling GSA_address_in_use. Adresses will
+ *    mark the address as used an notify the solver about the use.
+ *
+ *       1.7.8 Address lifecycle
+ *
+ *      * (add address)
+ *      * (updated address) || (address in use)
+ *      * (delete address)
+ *
+ *     1.8 Bandwidth assignment
+ *
+ *    The addresses are used to perform resource allocation operations. ATS
+ *    addresses takes care of instantiating the solver configured and notifies
+ *    the respective solver about address changes and receives changes to the
+ *    bandwidth assignment from the solver. The current bandwidth assignment is
+ *    sent to transport. The specific solvers will be described in the specific
+ *    section.
+ *
+ *     1.9 Changing peer preferences
+ *
+ *    The bandwidth assigned to a peer can be influenced by setting a preference
+ *    for a peer. The prefernce will be given to to the solver with s_pref which
+ *    has to take care of the preference value
+
+ */
+
 #define ATS_BLOCKING_DELTA GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 100)
 
 struct GAS_Addresses_Handle;
@@ -233,10 +425,14 @@ typedef void
 
 
 /**
- * Initialize address subsystem.
+ * Initialize address subsystem. The addresses subsystem manages the addresses
+ * known and current performance information. It has a solver component
+ * responsible for the resource allocation. It tells the solver about changes
+ * and receives updates when the solver changes the ressource allocation.
  *
  * @param cfg configuration to use
  * @param stats the statistics handle to use
+ * @return an address handle
  */
 struct GAS_Addresses_Handle *
 GAS_addresses_init (const struct GNUNET_CONFIGURATION_Handle *cfg,
@@ -244,22 +440,63 @@ GAS_addresses_init (const struct GNUNET_CONFIGURATION_Handle *cfg,
 
 /**
  * Shutdown address subsystem.
+ *
+ * @param the address handle to shutdown
  */
 void
 GAS_addresses_done (struct GAS_Addresses_Handle *handle);
 
+
+/**
+ * Add a new address for a peer.
+ *
+ * @param handle the address handle to use
+ * @param peer peer
+ * @param plugin_name transport plugin name
+ * @param plugin_addr plugin address
+ * @param plugin_addr_len length of the plugin address
+ * @param session_id session id, can be 0
+ * @param atsi performance information for this address
+ * @param atsi_count number of performance information contained
+ */
 void
-GAS_addresses_handle_backoff_reset (struct GAS_Addresses_Handle *handle,
-                                    const struct GNUNET_PeerIdentity *peer);
+GAS_addresses_add (struct GAS_Addresses_Handle *handle,
+                   const struct GNUNET_PeerIdentity *peer,
+                   const char *plugin_name,
+                   const void *plugin_addr,
+                   size_t plugin_addr_len,
+                   uint32_t session_id,
+                   const struct GNUNET_ATS_Information *atsi,
+                   uint32_t atsi_count);
+
 
 /**
- * This address is now used or not used anymore
+ * Notification about active use of an address.
+ * in_use == GNUNET_YES:
+ *      This address is used to maintain an active connection with a peer.
+ * in_use == GNUNET_NO:
+ *      This address is no longer used to maintain an active connection with a peer.
+ *
+ * Note: can only be called with in_use == GNUNET_NO if called with GNUNET_YES
+ * before
+ *
+ * @param handle the address handle to use
+ * @param peer peer
+ * @param plugin_name transport plugin name
+ * @param plugin_addr plugin address
+ * @param plugin_addr_len length of the plugin address
+ * @param session_id session id, can be 0
+ * @param in_use GNUNET_YES if GNUNET_NO
+ * @return GNUNET_SYSERR on failure (address unknown ...)
  */
 int
 GAS_addresses_in_use (struct GAS_Addresses_Handle *handle,
                       const struct GNUNET_PeerIdentity *peer,
-                      const char *plugin_name, const void *plugin_addr,
-                      size_t plugin_addr_len, uint32_t session_id, int in_use);
+                      const char *plugin_name,
+                      const void *plugin_addr,
+                      size_t plugin_addr_len,
+                      uint32_t session_id,
+                      int in_use);
 
 void
 GAS_addresses_update (struct GAS_Addresses_Handle *handle,
@@ -281,6 +518,10 @@ void
 GAS_addresses_destroy_all (struct GAS_Addresses_Handle *handle);
 
 
+void
+GAS_addresses_request_address (struct GAS_Addresses_Handle *handle,
+                               const struct GNUNET_PeerIdentity *peer);
+
 /**
  * Cancel address suggestions for a peer
  *
@@ -290,9 +531,16 @@ void
 GAS_addresses_request_address_cancel (struct GAS_Addresses_Handle *handle,
                                       const struct GNUNET_PeerIdentity *peer);
 
+
+
+
+/**
+ *
+ */
 void
-GAS_addresses_request_address (struct GAS_Addresses_Handle *handle,
-                               const struct GNUNET_PeerIdentity *peer);
+GAS_addresses_handle_backoff_reset (struct GAS_Addresses_Handle *handle,
+                                    const struct GNUNET_PeerIdentity *peer);
+
 
 void
 GAS_addresses_change_preference (struct GAS_Addresses_Handle *handle,
@@ -301,13 +549,6 @@ GAS_addresses_change_preference (struct GAS_Addresses_Handle *handle,
                                  enum GNUNET_ATS_PreferenceKind kind,
                                  float score);
 
-void
-GAS_addresses_add (struct GAS_Addresses_Handle *handle,
-                   const struct GNUNET_PeerIdentity *peer,
-                   const char *plugin_name, const void *plugin_addr,
-                   size_t plugin_addr_len, uint32_t session_id,
-                   const struct GNUNET_ATS_Information *atsi,
-                   uint32_t atsi_count);
 
 
 typedef void (*GNUNET_ATS_Peer_Iterator) (void *p_it_cls,