Source: ../../bgp/route_table_deletion.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// Copyright (c) 2001-2005 International Computer Science Institute
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/bgp/route_table_deletion.hh,v 1.17 2005/03/25 02:52:46 pavlin Exp $
#ifndef __BGP_ROUTE_TABLE_DELETION_HH__
#define __BGP_ROUTE_TABLE_DELETION_HH__
#include "route_table_base.hh"
#include "peer_handler.hh"
#include "bgp_trie.hh"
class EventLoop;
/**
* @short DeletionTable is a temporary BGPRouteTable used to delete
* routes when a peer goes down
*
* When a peer goes down, all the routes stored in a RibIn need to be
* deleted. However, this can take some time, so it cannot occur in
* one atomic operation, so it must be done route-by-route as a
* background task. This is complicated by the fact that the peering
* may come back up while this background deletion is occuring, and
* new routes may appear. To handle the background deletion while
* keeping the RibIn simple, we simply create a new DeletionTable
* route table, plumb it in directly after the RibIn, and pass the
* RibIn's entire route trie to the DeletionTable. RibIn can now
* forget these routes ever existed, and DeletionTable can get on with
* the background deletion task, unplumbing and deleting itself when
* no routes remain.
*
* Care must be taken to ensure that the downstream routing tables see
* consistent information. For example, if there is a route for
* subnet X in the DeletionTable that has not yet been deleted, and an
* add_route for X comes downstream from rthe RibIn, then this would
* need to be propagated downstream as a replace_route.
*
* Note that if a peering flaps multiple times, multiple
* DeletionTables may be plumbed in, one after another, behind a
* RibInTable.
*/
template<class A>
class DeletionTable : public BGPRouteTable<A> {
public:
DeletionTable(string tablename,
Safi safi,
BgpTrie<A>* route_table,
const PeerHandler *peer,
uint32_t genid,
BGPRouteTable<A> *parent);
~DeletionTable();
int add_route(const InternalMessage<A> &rtmsg,
BGPRouteTable<A> *caller);
int replace_route(const InternalMessage<A> &old_rtmsg,
const InternalMessage<A> &new_rtmsg,
BGPRouteTable<A> *caller);
int delete_route(const InternalMessage<A> &rtmsg,
BGPRouteTable<A> *caller);
int route_dump(const InternalMessage<A> &rtmsg,
BGPRouteTable<A> *caller,
const PeerHandler *dump_peer);
int push(BGPRouteTable<A> *caller);
const SubnetRoute<A> *lookup_route(const IPNet<A> &net,
uint32_t& genid) const;
void route_used(const SubnetRoute<A>* route, bool in_use);
RouteTableType type() const { return DELETION_TABLE; }
string str() const;
/* mechanisms to implement flow control in the output plumbing */
void output_state(bool /*busy*/, BGPRouteTable<A> */*next_table*/) {
abort();
}
bool get_next_message(BGPRouteTable<A> */*next_table*/) {
abort();
return false;
}
void initiate_background_deletion();
/**
* @return the generation id.
*/
uint32_t genid() const {return _genid;}
private:
void unplumb_self();
void delete_next_chain();
EventLoop& eventloop() const {
return _peer->eventloop();
}
const PeerHandler *_peer;
uint32_t _genid;
BgpTrie<A>* _route_table;
typename BgpTrie<A>::PathmapType::const_iterator _del_sweep;
int _deleted, _chains;
XorpTimer _deletion_timer;
};
#endif // __BGP_ROUTE_TABLE_DELETION_HH__
Generated by: pavlin on possum.icir.org on Thu Mar 9 04:43:34 2006, using kdoc $.