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| [root@lab103 udp]
package main
import (
"fmt"
"net"
"os"
"strconv"
"sync"
"time"
)
func startUDPFileServer(wg *sync.WaitGroup, host string, port int, bufferSize int, filePath string, targetSpeedMbps int) {
defer wg.Done()
addr := fmt.Sprintf("%s:%d", host, port)
udpAddr, err := net.ResolveUDPAddr("udp", addr)
if err != nil {
fmt.Printf("Failed to resolve address: %v\n", err)
return
}
conn, err := net.ListenUDP("udp", udpAddr)
if err != nil {
fmt.Printf("Failed to listen on %s: %v\n", addr, err)
return
}
defer conn.Close()
fmt.Printf("UDP File server started, listening on %s...\n", addr)
targetSpeedBps := targetSpeedMbps * 1024 * 1024
buffer := make([]byte, bufferSize)
for {
n, clientAddr, err := conn.ReadFromUDP(buffer)
if err != nil {
fmt.Printf("Error receiving data: %v\n", err)
continue
}
request := string(buffer[:n])
fmt.Printf("Received request from %v: %s\n", clientAddr, request)
if request == "GET" {
if _, err := os.Stat(filePath); os.IsNotExist(err) {
conn.WriteToUDP([]byte("FILE_NOT_FOUND"), clientAddr)
fmt.Println("File not found")
continue
}
file, err := os.Open(filePath)
if err != nil {
fmt.Printf("Failed to open file: %v\n", err)
continue
}
defer file.Close()
totalSent := 0
startTime := time.Now()
for {
n, err := file.Read(buffer)
if err != nil {
break
}
_, err = conn.WriteToUDP(buffer[:n], clientAddr)
if err != nil {
fmt.Printf("Error sending data: %v\n", err)
break
}
totalSent += n
// 控制发送速度
timeElapsed := time.Since(startTime).Seconds()
expectedTime := float64(totalSent) / float64(targetSpeedBps)
if timeElapsed < expectedTime {
time.Sleep(time.Duration(expectedTime-timeElapsed) * time.Second)
}
}
conn.WriteToUDP([]byte("END"), clientAddr)
fmt.Println("File sent successfully")
} else {
conn.WriteToUDP([]byte("INVALID_REQUEST"), clientAddr)
fmt.Println("Invalid request")
}
}
}
func runServersOnMultiplePorts(host string, startPort, endPort int, bufferSize int, filePath string, targetSpeedMbps int) {
var wg sync.WaitGroup
for port := startPort; port <= endPort; port++ {
wg.Add(1)
go startUDPFileServer(&wg, host, port, bufferSize, filePath, targetSpeedMbps)
}
wg.Wait()
}
func main() {
if len(os.Args) != 4 {
fmt.Println("Usage: go run server.go <host> <start_port> <end_port>")
return
}
host := os.Args[1]
startPort, err1 := strconv.Atoi(os.Args[2])
endPort, err2 := strconv.Atoi(os.Args[3])
if err1 != nil || err2 != nil {
fmt.Println("Invalid port number")
return
}
runServersOnMultiplePorts(host, startPort, endPort, 1024, "video.mp4", 2)
}
|
