lossy
v0.2.1
Paquete Go para simular ancho de banda, latencia y pérdida de paquetes para interfaces net.PacketConn y net.Conn.
Su uso principal es probar la solidez de aplicaciones y protocolos de red ejecutados sobre protocolos de transporte no confiables como UDP o IP. Como beneficio adicional, también se puede utilizar como limitador de ancho de banda saliente.
Lossy solo altera el lado de escritura de la conexión, el lado de lectura se mantiene como está.
package main
import (
"fmt"
"github.com/cevatbarisyilmaz/lossy"
"log"
"math/rand"
"net"
"time"
)
const packetSize = 64
func main () {
// Create two connection endpoints over UDP
packetConn , conn := createConnections ()
// Create a lossy packet connection
bandwidth := 1048 // 8 Kbit/s
minLatency := 100 * time . Millisecond
maxLatency := time . Second
packetLossRate := 0.33
headerOverhead := lossy . UDPv4MinHeaderOverhead
lossyPacketConn := lossy . NewPacketConn ( packetConn , bandwidth , minLatency , maxLatency , packetLossRate , headerOverhead )
// Write some packets via lossy
var bytesWritten int
const packetCount = 32
go func () {
for i := 0 ; i < packetCount ; i ++ {
packet := createPacket ()
_ , err := lossyPacketConn . WriteTo ( packet , conn . LocalAddr ())
if err != nil {
log . Fatal ( err )
}
bytesWritten += len ( packet ) + headerOverhead
}
fmt . Println ( "Sent" , packetCount , "packets with total size of" , bytesWritten , "bytes" )
baseTransmissionDuration := time . Duration ( float64 ( bytesWritten * int ( time . Second )) / float64 ( bandwidth ))
earliestCompletion := baseTransmissionDuration + minLatency
latestCompletion := baseTransmissionDuration + maxLatency
fmt . Println ( "Expected transmission duration is between" , earliestCompletion , "and" , latestCompletion )
}()
// Read packets at the other side
const timeout = 3 * time . Second
var packets , bytesRead int
startTime := time . Now ()
for {
_ = conn . SetReadDeadline ( time . Now (). Add ( timeout ))
buffer := make ([] byte , packetSize )
n , err := conn . Read ( buffer )
if err != nil {
break
}
bytesRead += n + headerOverhead
packets ++
}
dur := time . Now (). Sub ( startTime ) - timeout
fmt . Println ( "Received" , packets , "packets with total size of" , bytesRead , "bytes in" , dur )
// Close the connections
_ = lossyPacketConn . Close ()
_ = conn . Close ()
}
func createConnections () (net. PacketConn , net. Conn ) {
packetConn , err := net . ListenUDP ( "udp" , & net. UDPAddr {
IP : net . IPv4 ( 127 , 0 , 0 , 1 ),
Port : 0 ,
})
if err != nil {
log . Fatal ( err )
}
conn , err := net . DialUDP ( "udp" , nil , packetConn . LocalAddr ().( * net. UDPAddr ))
if err != nil {
log . Fatal ( err )
}
return packetConn , conn
}
func createPacket () [] byte {
packet := make ([] byte , packetSize )
rand . Read ( packet )
return packet
}
Producción
Sent 32 packets with total size of 2944 bytes
Expected transmission duration is between 2.909160305s and 3.809160305s
Received 23 packets with total size of 2116 bytes in 3.2507523s