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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 (
"encoding/hex"
"fmt"
"gnunet/crypto"
"gnunet/enums"
"gnunet/util"
"github.com/bfix/gospel/data"
)
//----------------------------------------------------------------------
// Query/Block interfaces for generic DHT handling
//----------------------------------------------------------------------
// DHT Query interface
type Query interface {
// Key returns the DHT key for a block
Key() *crypto.HashCode
// Type returns the requested block type
Type() uint16
// Flags returns the query flags
Flags() uint16
// Verify the integrity of a retrieved block (optional). Override in
// custom query types to implement block-specific integrity checks
// (see GNSQuery for example).
Verify(blk Block) error
// Decrypt block content (optional). Override in custom query types to
// implement block-specific encryption (see GNSQuery for example).
Decrypt(blk Block) error
// String returns the human-readable representation of a query
String() string
}
// DHT Block interface
type Block interface {
// Data returns the DHT block data (unstructured without type and
// expiration information.
Data() []byte
// Return the block type
Type() uint16
// Expire returns the block expiration
Expire() util.AbsoluteTime
// Verify the integrity of a block (optional). Override in custom query
// types to implement block-specific integrity checks (see GNSBlock for
// example). This verification is usually weaker than the verification
// method from a Query (see GNSBlock.Verify for explanation).
Verify() (bool, error)
// String returns the human-readable representation of a block
String() string
}
// Unwrap (raw) block to a specific block type
func Unwrap(blk Block, obj interface{}) error {
return data.Unmarshal(obj, blk.Data())
}
//----------------------------------------------------------------------
// Generic interface implementations without persistent attributes
//----------------------------------------------------------------------
// GenericQuery is the binary representation of a DHT key
type GenericQuery struct {
// Key for repository queries (local/remote)
key *crypto.HashCode
// block type requested
btype uint16
// query flags
flags uint16
// Params holds additional query parameters
Params util.ParameterSet
}
// Key interface method implementation
func (q *GenericQuery) Key() *crypto.HashCode {
return q.key
}
// Type returns the requested block type
func (q *GenericQuery) Type() uint16 {
return q.btype
}
// Flags returns the query flags
func (q *GenericQuery) Flags() uint16 {
return q.flags
}
// Verify interface method implementation
func (q *GenericQuery) Verify(b Block) error {
// no verification, no errors ;)
return nil
}
// Decrypt interface method implementation
func (q *GenericQuery) Decrypt(b Block) error {
// no decryption, no errors ;)
return nil
}
// String returns the human-readable representation of a block
func (q *GenericQuery) String() string {
return fmt.Sprintf("GenericQuery{btype=%d,key=%s}", q.btype, hex.EncodeToString(q.Key().Bits))
}
// NewGenericQuery creates a simple Query from hash code.
func NewGenericQuery(key []byte, btype enums.BlockType, flags uint16) *GenericQuery {
return &GenericQuery{
key: crypto.NewHashCode(key),
btype: uint16(btype),
flags: flags,
Params: make(util.ParameterSet),
}
}
//----------------------------------------------------------------------
// GenericBlock is the block in simple binary representation
type GenericBlock struct {
block []byte // block data
btype uint16 // block type
expire util.AbsoluteTime // expiration date
}
// Data interface method implementation
func (b *GenericBlock) Data() []byte {
return b.block
}
// Type returns the block type
func (b *GenericBlock) Type() uint16 {
return b.btype
}
// Expire returns the block expiration
func (b *GenericBlock) Expire() util.AbsoluteTime {
return b.expire
}
// String returns the human-readable representation of a block
func (b *GenericBlock) String() string {
return fmt.Sprintf("GenericBlock{type=%d,expires=%s,data=[%d]}",
b.btype, b.expire.String(), len(b.block))
}
// Verify interface method implementation
func (b *GenericBlock) Verify() (bool, error) {
// no verification, no errors ;)
return true, nil
}
// NewGenericBlock creates a Block from binary data.
func NewGenericBlock(buf []byte) *GenericBlock {
return &GenericBlock{
block: util.Clone(buf),
btype: uint16(enums.BLOCK_TYPE_ANY), // unknown block type
expire: util.AbsoluteTimeNever(), // never expires
}
}
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