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https://github.com/mudler/edgevpn.git
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f5ea51d82e
As EdgeVPN can be used as library and it turns out to be quite useful, change license for follow up versions to Apache so can be used as a library easilier.
77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
/*
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Copyright © 2021-2022 Ettore Di Giacinto <mudler@mocaccino.org>
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package blockchain
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import (
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"time"
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)
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type DataString string
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// Block represents each 'item' in the blockchain
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type Block struct {
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Index int
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Timestamp string
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Storage map[string]map[string]Data
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Hash string
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PrevHash string
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}
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// Blockchain is a series of validated Blocks
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type Blockchain []Block
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// make sure block is valid by checking index, and comparing the hash of the previous block
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func (newBlock Block) IsValid(oldBlock Block) bool {
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if oldBlock.Index+1 != newBlock.Index {
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return false
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}
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if oldBlock.Hash != newBlock.PrevHash {
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return false
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}
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if newBlock.Checksum() != newBlock.Hash {
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return false
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}
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return true
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}
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// Checksum does SHA256 hashing of the block
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func (b Block) Checksum() string {
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record := fmt.Sprint(b.Index, b.Timestamp, b.Storage, b.PrevHash)
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h := sha256.New()
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h.Write([]byte(record))
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hashed := h.Sum(nil)
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return hex.EncodeToString(hashed)
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}
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// create a new block using previous block's hash
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func (oldBlock Block) NewBlock(s map[string]map[string]Data) Block {
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var newBlock Block
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t := time.Now().UTC()
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newBlock.Index = oldBlock.Index + 1
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newBlock.Timestamp = t.String()
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newBlock.Storage = s
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newBlock.PrevHash = oldBlock.Hash
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newBlock.Hash = newBlock.Checksum()
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return newBlock
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}
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