114 lines
2.4 KiB
Go
114 lines
2.4 KiB
Go
package v5
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import (
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"bytes"
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"sync"
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"github.com/metacubex/mihomo/common/cache"
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"github.com/metacubex/quic-go"
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)
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// MaxFragSize is a safe udp relay packet size
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// because tuicv5 support udp fragment so we unneeded to do a magic modify for quic-go to increase MaxDatagramFrameSize
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// it may not work fine in some platform
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var MaxFragSize = 1200 - PacketOverHead
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func fragWriteNative(quicConn quic.Connection, packet Packet, buf *bytes.Buffer, fragSize int) (err error) {
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fullPayload := packet.DATA
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off := 0
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fragID := uint8(0)
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fragCount := uint8((len(fullPayload) + fragSize - 1) / fragSize) // round up
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packet.FRAG_TOTAL = fragCount
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for off < len(fullPayload) {
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payloadSize := len(fullPayload) - off
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if payloadSize > fragSize {
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payloadSize = fragSize
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}
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frag := packet
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frag.FRAG_ID = fragID
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frag.SIZE = uint16(payloadSize)
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frag.DATA = fullPayload[off : off+payloadSize]
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off += payloadSize
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fragID++
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buf.Reset()
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err = frag.WriteTo(buf)
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if err != nil {
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return
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}
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data := buf.Bytes()
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err = quicConn.SendMessage(data)
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if err != nil {
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return
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}
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packet.ADDR.TYPE = AtypNone // avoid "fragment 2/2: address in non-first fragment"
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}
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return
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}
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type deFragger struct {
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lru *cache.LruCache[uint16, *packetBag]
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once sync.Once
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}
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type packetBag struct {
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frags []*Packet
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count uint8
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mutex sync.Mutex
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}
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func newPacketBag() *packetBag {
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return new(packetBag)
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}
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func (d *deFragger) init() {
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if d.lru == nil {
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d.lru = cache.New(
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cache.WithAge[uint16, *packetBag](10),
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cache.WithUpdateAgeOnGet[uint16, *packetBag](),
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)
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}
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}
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func (d *deFragger) Feed(m *Packet) *Packet {
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if m.FRAG_TOTAL <= 1 {
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return m
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}
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if m.FRAG_ID >= m.FRAG_TOTAL {
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// wtf is this?
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return nil
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}
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d.once.Do(d.init) // lazy init
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bag, _ := d.lru.GetOrStore(m.PKT_ID, newPacketBag)
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bag.mutex.Lock()
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defer bag.mutex.Unlock()
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if int(m.FRAG_TOTAL) != len(bag.frags) {
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// new message, clear previous state
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bag.frags = make([]*Packet, m.FRAG_TOTAL)
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bag.count = 1
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bag.frags[m.FRAG_ID] = m
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return nil
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}
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if bag.frags[m.FRAG_ID] != nil {
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return nil
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}
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bag.frags[m.FRAG_ID] = m
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bag.count++
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if int(bag.count) != len(bag.frags) {
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return nil
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}
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// all fragments received, assemble
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var data []byte
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for _, frag := range bag.frags {
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data = append(data, frag.DATA...)
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}
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p := *bag.frags[0] // recover from first fragment
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p.SIZE = uint16(len(data))
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p.DATA = data
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p.FRAG_ID = 0
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p.FRAG_TOTAL = 1
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bag.frags = nil
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d.lru.Delete(m.PKT_ID)
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return &p
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}
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