99 lines
1.8 KiB
Go
99 lines
1.8 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
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*/
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package device
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import (
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"crypto/rand"
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"encoding/binary"
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"sync"
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)
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type IndexTableEntry struct {
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peer *Peer
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handshake *Handshake
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keypair *Keypair
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}
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type IndexTable struct {
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sync.RWMutex
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table map[uint32]IndexTableEntry
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}
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func randUint32() (uint32, error) {
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var integer [4]byte
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_, err := rand.Read(integer[:])
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// Arbitrary endianness; both are intrinsified by the Go compiler.
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return binary.LittleEndian.Uint32(integer[:]), err
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}
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func (table *IndexTable) Init() {
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table.Lock()
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defer table.Unlock()
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table.table = make(map[uint32]IndexTableEntry)
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}
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func (table *IndexTable) Delete(index uint32) {
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table.Lock()
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defer table.Unlock()
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delete(table.table, index)
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}
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func (table *IndexTable) SwapIndexForKeypair(index uint32, keypair *Keypair) {
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table.Lock()
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defer table.Unlock()
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entry, ok := table.table[index]
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if !ok {
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return
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}
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table.table[index] = IndexTableEntry{
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peer: entry.peer,
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keypair: keypair,
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handshake: nil,
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}
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}
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func (table *IndexTable) NewIndexForHandshake(peer *Peer, handshake *Handshake) (uint32, error) {
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for {
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// generate random index
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index, err := randUint32()
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if err != nil {
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return index, err
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}
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// check if index used
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table.RLock()
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_, ok := table.table[index]
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table.RUnlock()
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if ok {
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continue
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}
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// check again while locked
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table.Lock()
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_, found := table.table[index]
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if found {
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table.Unlock()
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continue
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}
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table.table[index] = IndexTableEntry{
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peer: peer,
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handshake: handshake,
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keypair: nil,
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}
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table.Unlock()
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return index, nil
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}
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}
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func (table *IndexTable) Lookup(id uint32) IndexTableEntry {
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table.RLock()
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defer table.RUnlock()
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return table.table[id]
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}
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