mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-12-22 18:17:52 -05:00
76 lines
1.5 KiB
Go
76 lines
1.5 KiB
Go
package kcp
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import (
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"hash/fnv"
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"github.com/v2ray/v2ray-core/common/alloc"
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"github.com/v2ray/v2ray-core/common/serial"
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)
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type Authenticator interface {
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HeaderSize() int
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// Encrypt encrypts the whole block in src into dst.
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// Dst and src may point at the same memory.
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Seal(buffer *alloc.Buffer)
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// Decrypt decrypts the whole block in src into dst.
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// Dst and src may point at the same memory.
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Open(buffer *alloc.Buffer) bool
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}
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type SimpleAuthenticator struct{}
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func NewSimpleAuthenticator() Authenticator {
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return &SimpleAuthenticator{}
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}
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func (this *SimpleAuthenticator) HeaderSize() int {
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return 6
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}
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func (this *SimpleAuthenticator) Seal(buffer *alloc.Buffer) {
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buffer.PrependUint16(uint16(buffer.Len()))
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fnvHash := fnv.New32a()
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fnvHash.Write(buffer.Value)
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buffer.SliceBack(4)
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fnvHash.Sum(buffer.Value[:0])
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len := buffer.Len()
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xtra := 4 - len%4
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if xtra != 0 {
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buffer.Slice(0, len+xtra)
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}
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xorfwd(buffer.Value)
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if xtra != 0 {
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buffer.Slice(0, len)
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}
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}
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func (this *SimpleAuthenticator) Open(buffer *alloc.Buffer) bool {
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len := buffer.Len()
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xtra := 4 - len%4
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if xtra != 0 {
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buffer.Slice(0, len+xtra)
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}
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xorbkd(buffer.Value)
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if xtra != 0 {
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buffer.Slice(0, len)
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}
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fnvHash := fnv.New32a()
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fnvHash.Write(buffer.Value[4:])
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if serial.BytesToUint32(buffer.Value[:4]) != fnvHash.Sum32() {
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return false
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}
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length := serial.BytesToUint16(buffer.Value[4:6])
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if buffer.Len()-6 != int(length) {
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return false
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}
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buffer.SliceFrom(6)
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return true
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}
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