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// This file is part of gnunet-go, a GNUnet-implementation in Golang.
// Copyright (C) 2019-2022 Bernd Fix >Y<
//
// gnunet-go is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// gnunet-go 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
// Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: AGPL3.0-or-later
package blocks
import (
"gnunet/crypto"
"gnunet/enums"
)
// BlockHandler interface defines methods specific to block types.
type BlockHandler interface {
// Parse a block instance from binary data
ParseBlock(buf []byte) (Block, error)
// ValidateBlockQuery is used to evaluate the request for a block as part
// of DHT-P2P-GET processing. Here, the block payload is unknown, but if
// possible the XQuery and Key SHOULD be verified.
ValidateBlockQuery(key *crypto.HashCode, xquery []byte) bool
// ValidateBlockKey returns true if the block key is the same as the
// query key used to access the block.
ValidateBlockKey(b Block, key *crypto.HashCode) bool
// DeriveBlockKey is used to synthesize the block key from the block
// payload as part of PutMessage and ResultMessage processing. The special
// return value of 'nil' implies that this block type does not permit
// deriving the key from the block. A Key may be returned for a block that
// is ill-formed.
DeriveBlockKey(b Block) *crypto.HashCode
// ValidateBlockStoreRequest is used to evaluate a block payload as part of
// PutMessage and ResultMessage processing.
ValidateBlockStoreRequest(b Block) bool
// SetupResultFilter is used to setup an empty result filter. The arguments
// are the set of results that must be filtered at the initiator, and a
// MUTATOR value which MAY be used to deterministically re-randomize
// probabilistic data structures.
SetupResultFilter(filterSize int, mutator uint32) ResultFilter
// ParseResultFilter from binary data
ParseResultFilter(data []byte) ResultFilter
// FilterResult is used to filter results against specific queries. This
// function does not check the validity of the block itself or that it
// matches the given key, as this must have been checked earlier. Thus,
// locally stored blocks from previously observed ResultMessages and
// PutMessages use this function to perform filtering based on the request
// parameters of a particular GET operation. Possible values for the
// FilterEvaluationResult are defined above. If the main evaluation result
// is RF_MORE, the function also returns and updated result filter where
// the block is added to the set of filtered replies. An implementation is
// not expected to actually differentiate between the RF_DUPLICATE and
// RF_IRRELEVANT return values: in both cases the block is ignored for
// this query.
FilterResult(b Block, key *crypto.HashCode, rf ResultFilter, xQuery []byte) int
}
// BlockHandlers is a map of block query validation implementations
// for supported block types.
var BlockHandlers map[enums.BlockType]BlockHandler
// initializer function
func init() {
// create map instance
BlockHandlers = make(map[enums.BlockType]BlockHandler)
// add validation functions
BlockHandlers[enums.BLOCK_TYPE_DHT_HELLO] = new(HelloBlockHandler)
BlockHandlers[enums.BLOCK_TYPE_TEST] = new(TestBlockHandler)
}
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