mirror of
https://github.com/e1732a364fed/v2ray_simple.git
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138 lines
2.9 KiB
Go
138 lines
2.9 KiB
Go
package utils
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import (
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"io"
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"sync"
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"syscall"
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)
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var (
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// readv pool, 缓存 mr和buffers，进一步减轻内存分配负担
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readvPool sync.Pool
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)
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const (
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Readv_buffer_allocLen = 8
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ReadvSingleBufLen = 4096
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)
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func init() {
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readvPool = sync.Pool{
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New: newReadvMem,
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}
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//预先放进去两个
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readvPool.Put(newReadvMem())
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readvPool.Put(newReadvMem())
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}
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// 缓存 ReadvMem 以及对应分配的系统相关的 SystemReadver.
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// 使用 ReadvMem的最大好处就是 buffers 和 mr 都是不需要 释放的.
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//
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// 因为不需释放mr, 所以也就节省了多次 mr.Init 的开销.
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//
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// 该 ReadvMem 以及 readvPool 专门服务于 TryCopy 函数.
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type ReadvMem struct {
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Buffers [][]byte
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Mr SystemReadver
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}
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func allocReadvBuffers(mr SystemReadver, len int) [][]byte {
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bs := make([][]byte, len)
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for i := range bs {
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// 这里单独make，而不是从 其它pool中获取, 这样可以做到专用
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bs[i] = make([]byte, ReadvSingleBufLen)
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}
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mr.Init(bs, ReadvSingleBufLen)
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return bs
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}
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func newReadvMem() any {
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mr := GetReadVReader()
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return &ReadvMem{
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Mr: mr,
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Buffers: allocReadvBuffers(mr, Readv_buffer_allocLen),
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}
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}
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func Get_readvMem() *ReadvMem {
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return readvPool.Get().(*ReadvMem)
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}
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// 将创建好的rm放回 readvPool
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func Put_readvMem(rm *ReadvMem) {
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rm.Buffers = RecoverBuffers(rm.Buffers, Readv_buffer_allocLen, ReadvSingleBufLen)
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readvPool.Put(rm)
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}
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/*
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ReadvFrom 用于读端 为rawRead的情况，如 从socks5或direct读取 数据, 等裸协议的情况。
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rm可为nil，但不建议，因为提供非nil的readvMem 可以节省内存分配开销。
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返回错误时，会返回 原buffer 或 在函数内部新分配的buffer.
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本函数不负责 释放分配的内存. 因为有时需要重复利用缓存。
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TryCopy函数使用到了本函数 来进行readv相关操作。
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*/
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func ReadvFrom(rawReadConn syscall.RawConn, rm *ReadvMem) ([][]byte, error) {
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if rm == nil {
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rm = Get_readvMem()
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}
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allocedBuffers := rm.Buffers
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var nBytes uint32
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err := rawReadConn.Read(func(fd uintptr) bool {
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n, e := rm.Mr.Read(fd)
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if e != nil {
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return false
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}
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nBytes = n
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return true
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})
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if err != nil {
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return allocedBuffers, err
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}
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if nBytes == 0 {
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return allocedBuffers, io.EOF
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}
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nBuf := ShrinkBuffers(allocedBuffers, int(nBytes), ReadvSingleBufLen)
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return allocedBuffers[:nBuf], nil
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}
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/*
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// 依次试图使用 readv、ReadBuffers 以及 原始 Read 读取数据
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func ReadBuffersFrom(c io.Reader, rawReadConn syscall.RawConn, mr MultiReader) (buffers [][]byte, err error) {
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if rawReadConn != nil {
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readv_mem := Get_readvMem()
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//defer put_readvMem(readv_mem) //因为返回的buffers还需使用, 所以不能立刻放回 readv_mem
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buffers, err = ReadvFrom(rawReadConn, readv_mem)
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} else if mr != nil {
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return mr.ReadBuffers()
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} else {
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packet := GetPacket()
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var n int
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n, err = c.Read(packet)
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if err != nil {
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return
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}
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buffers = append(buffers, packet[:n])
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}
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return
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}
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*/
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