- *
- * 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
- *
- * ATS addresses : proportional solver
- *
- * The proportional solver ("proportional") distributes the available
- * bandwidth fair over all the addresses influenced by the
- * preference values. For each available network type an in- and
- * outbound quota is configured and the bandwidth available in
- * these networks is distributed over the addresses. The solver
- * first assigns every addresses the minimum amount of bandwidth
- * GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT and then distributes the
- * remaining bandwidth available according to the preference
- * values. For each peer only a single address gets bandwidth
- * assigned and only one address marked as active. The most
- * important functionality for the solver is implemented in: *
- * find_address_it is an hashmap iterator returning the prefered
- * address for an peer * update_quota_per_network distributes
- * available bandwidth for a network over active addresses
- *
- * Changes to addresses automatically have an impact on the the
- * bandwidth assigned to other addresses in the same network since
- * the solver distributes the remaining bandwidth over the
- * addresses in the network. When changes to the addresses occur,
- * the solver first performs the changes, like adding or deleting
- * addresses, and then updates bandwidth assignment for the
- * affected network. Bandwidth assignment is only recalculated on
- * demand when an address is requested by a client for a peer or
- * when the addresses available have changed or an address changed
- * the network it is located in. When the bandwidth assignment has
- * changed the callback is called with the new bandwidth
- * assignments. The bandwidth distribution for a network is
- * recalculated due to: * address suggestion requests * address
- * deletions * address switching networks during address update *
- * preference changes
- *
- * 3.1 Data structures used
- *
- * For each ATS network (e.g. WAN, LAN, loopback) a struct Network
- * is used to specify network related information as total adresses
- * and active addresses in this network and the configured in- and
- * outbound quota. Each network also contains a list of addresses
- * added to the solver located in this network. The proportional
- * solver uses the addresses' solver_information field to store the
- * proportional network it belongs to for each address.
- *
- * 3.2 Initializing
- *
- * When the proportional solver is initialized the solver creates a
- * new solver handle and initializes the network structures with
- * the quotas passed from addresses and returns the handle solver.
- *
- * 3.3 Adding an address
- *
- * When a new address is added to the solver using s_add, a lookup
- * for the network for this address is done and the address is
- * enqueued in in the linked list of the network.
- *
- * 3.4 Updating an address
- *
- * The main purpose of address updates is to update the ATS
- * information for addresse selection. Important for the proportional
- * solver is when an address switches network it is located
- * in. This is common because addresses added by transport's
- * validation mechanism are commonly located in
- * GNUNET_ATS_NET_UNSPECIFIED. Addresses in validation are located
- * in this network type and only if a connection is successful on
- * return of payload data transport switches to the real network
- * the address is located in. When an address changes networks it
- * is first of all removed from the old network using the solver
- * API function GAS_proportional_address_delete and the network in
- * the address struct is updated. A lookup for the respective new
- * proportional network is done and stored in the addresse's
- * solver_information field. Next the address is re-added to the
- * solver using the solver API function
- * GAS_proportional_address_add. If the address was marked as in
- * active, the solver checks if bandwidth is available in the
- * network and if yes sets the address to active and updates the
- * bandwidth distribution in this network. If no bandwidth is
- * available it sets the bandwidth for this address to 0 and tries
- * to suggest an alternative address. If an alternative address was
- * found, addresses' callback is called for this address.
- *
- * 3.5 Deleting an address
- *
- * When an address is removed from the solver, it removes the
- * respective address from the network and if the address was
- * marked as active, it updates the bandwidth distribution for this
- * network.
- *
- * 3.6 Requesting addresses
- *
- * When an address is requested for a peer the solver performs a
- * lookup for the peer entry in addresses address hashmap and
- * selects the best address. The selection of the most suitable
- * address is done in the find_address_it hashmap iterator
- * described in detail in section 3.7. If no address is returned,
- * no address can be suggested at the moment. If the address
- * returned is marked as active, the solver can return this
- * address. If the address is not marked as active, the solver
- * checks if another address belongign to this peer is marked as
- * active and marks the address as inactive, updates the bandwidth
- * for this address to 0, call the bandwidth changed callback for
- * this address due to the change and updates quota assignment for
- * the addresse's network. the now in-active address is belonging
- * to. The solver marks the new address as active and updates the
- * bandwidth assignment for this network.
- *
- * 3.7 Choosing addresses
- *
- * Choosing the best possible address for suggestion is done by
- * iterating over all addresses of a peer stored in addresses'
- * hashmap and using the hashmap iterator find_address_it to select
- * the best available address. Several checks are done when an
- * address is selected. First if this address is currently blocked
- * by addresses from being suggested. An address is blocked for the
- * duration of ATS_BLOCKING_DELTA when it is suggested to
- * transport. Next it is checked if at least
- * GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT bytes bandwidth is available
- * in the addresse's network, because suggesting an address without
- * bandwidth does not make sense. This also ensures that all active
- * addresses in this network get at least the minimum amount of
- * bandwidth assigned. In the next step the solver ensures that for
- * tcp connections inbound connections are prefered over outbound
- * connections. In the next stet the solver ensures that
- * connections are prefered in the following order: * connections
- * are already established and have bandwidth assigned *
- * connections with a shorter distance * connectes have a shorter
- * latency
- *
- * 3.8 Changing preferences
- *
- * 3.9 Shutdown
- *
- * During shutdown all network entries and aging processes are
- * destroyed and freed.
- *
- *
- * OLD DOCUMENTATION
- *
- * This solver assigns in and outbound bandwidth equally for all
- * addresses in specific network type (WAN, LAN) based on configured
- * in and outbound quota for this network.
- *
- * The solver is notified by addresses about changes to the addresses
- * and recalculates the bandwith assigned if required. The solver
- * notifies addresses by calling the GAS_bandwidth_changed_cb
- * callback.
- *
- * - Initialization
- *
- *
- *
- *
- * For each peer only a single is selected and marked as "active" in the address
- * struct.
- *
- * E.g.:
- *
- * You have the networks WAN and LAN and quotas
- * WAN_TOTAL_IN, WAN_TOTAL_OUT
- * LAN_TOTAL_IN, LAN_TOTAL_OUT
- *
- * If you have x addresses in the network segment LAN, the quotas are
- * QUOTA_PER_ADDRESS = LAN_TOTAL_OUT / x
- *
- * Quotas are automatically recalculated and reported back when addresses are
- * - requested
- *