[c++]udp的echo 程序

tcp的echo 程序很多，udp 很难找。
我把收集到的源码 发布出来。
linux 服务器
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define SERVER_PORT 8888
#define MAX_MSG_SIZE 1024

void udps_respon(int sockfd) {
    struct sockaddr_in addr;
    unsigned int addrlen;
    int n;
    char msg[MAX_MSG_SIZE];
     char show[MAX_MSG_SIZE+100];
    while(1) {
    // 从网络上读,写到网络上去
        // 初始化addr长度!
        addrlen = sizeof(addr);
        if((n = recvfrom(sockfd,msg,MAX_MSG_SIZE,0,
            (struct sockaddr *)&addr,&addrlen)) < 0) {
            fprintf(stderr,"Recveive packahe error:%s",
                strerror(errno));
            continue;
        }
        msg[n] ='/0';//原来是msg[n-1] ='/0';
        // 显示服务器端已经收到了信息
        snprintf(show,MAX_MSG_SIZE+100,"I have received %s from %sn",msg,
            inet_ntoa(addr.sin_addr));
        sendto(sockfd,msg,n,0,(struct sockaddr *)&addr,addrlen);
                printf("%s",show);
    }
}

int main(void) {
    int sockfd;
    struct sockaddr_in addr;
    sockfd = socket(AF_INET,SOCK_DGRAM,0);
    if(sockfd < 0) {
        fprintf(stderr,"Socket Error:%sn",strerror(errno));
        exit(1);
    }

    bzero(&addr,sizeof(struct sockaddr_in));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    addr.sin_port = htons(SERVER_PORT);

    if(bind(sockfd,(struct sockaddr *)&addr,
        sizeof(struct sockaddr_in)) < 0) {
        fprintf(stderr,"Bind Error:%sn",strerror(errno));
        exit(1);
    }

    udps_respon(sockfd);
    close(sockfd);
    exit(1);
}

c++ 源码

#include
#include
#include
#include
#include
#include

using namespace std;

int main(int argc, char *argv[])
{
    int s;
    char buffer[10];
   
    s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s < 0)
    {
        cout << "socket() error!" << endl;
    }
   
    sockaddr_in addr;
    bzero(&addr, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(5555);
   
    if (bind(s, (sockaddr*)(&addr), sizeof(addr)))
    {
        cout << "bind() error!" << endl;
    }
   
    while (1)
    {
        int recvSize;
        sockaddr_in recvAddr;
        socklen_t recvAddrLen = sizeof(recvAddr);
        bzero(&recvAddr, sizeof(recvAddr));
       
        recvSize = recvfrom(s, buffer, sizeof(buffer), 0, (sockaddr*)(&recvAddr), &recvAddrLen);
        if (recvSize < 0)
        {
            cout << "recvfrom() error!" << endl;
            continue;
        }
       
        int sendSize;
        sendSize = sendto(s, buffer, sizeof(buffer), 0, (sockaddr*)(&recvAddr), sizeof(recvAddr));
        if (sendSize < 0)
        {
            cout << "sendto() error!" << endl;
            continue;
        }
       
        cout << buffer << endl;
    }
    return EXIT_SUCCESS;
}
linux 客户端  可以移植到windows下
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define MAX_BUF_SIZE 1024

void udpc_request(int sockfd,const struct sockaddr_in *addr,int len) {
    char buffer[MAX_BUF_SIZE];
    int n;

    while(1) {
    // 从键盘读入,写到服务端
        fgets(buffer,MAX_BUF_SIZE,stdin);
        sendto(sockfd,buffer,strlen(buffer),0,(struct sockaddr *)addr,len);
        bzero(buffer,MAX_BUF_SIZE);
        // 从网络上读,写到屏幕上
        n = recvfrom(sockfd,buffer,MAX_BUF_SIZE,0,NULL,NULL);
        msg[n] ='/0';//原来是msg[n-1] ='/0';

        fprintf(stdout,"I received %s from server.n",buffer);
    }
}

int main(int argc,char **argv) {
    int sockfd,port;
    struct sockaddr_in addr;

    if(argc != 3)  {
        fprintf(stderr,"Usage:%s server_ip server_portn",argv[0]);
        exit(1);
    }
    if((port = atoi(argv[2])) < 0) {
        fprintf(stderr,"Usage:%s server_ip server_portn",argv[0]);
        exit(1);
    }
   
    sockfd = socket(AF_INET,SOCK_DGRAM,0);
    if(sockfd < 0) {
        fprintf(stderr,"Socket Error:%sn",strerror(errno));
        exit(1);
    }
    // 填充服务端的资料
    bzero(&addr,sizeof(struct sockaddr_in));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    if(inet_aton(argv[1],&addr.sin_addr) < 0) {
        fprintf(stderr,"IP error:%sn",strerror(errno));
        exit(1);
    }
    udpc_request(sockfd,&addr,sizeof(struct sockaddr_in));
    close(sockfd);
    exit(0);
}
c#的客户端
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace DefaultNamespace
{
 ///

 /// Description of Class1.
 ///

 public class UdpEchoClient
 {
  private static readonly int BUF_SIZE=2048;
 
  public static void Main(){
   Socket clientSocket=new Socket(AddressFamily.InterNetwork,
                                  SocketType.Dgram,
                                  ProtocolType.Udp
                                  );
   clientSocket.SetSocketOption(SocketOptionLevel.Socket,
                                 SocketOptionName.ReceiveTimeout,
                                 3000
                                 );
   EndPoint serverEndPoint=new IPEndPoint(IPAddress.Parse("127.0.0.1"),
                                          8004
                                          );
   Console.WriteLine("echo client start");
   while(true){
    string input=Console.ReadLine();
    if("exit"==input.ToLower()){
     clientSocket.Close();
     Console.WriteLine("echo client stop.");
     break;
    }
    byte[] buf=Encoding.ASCII.GetBytes(input);
    clientSocket.SendTo(buf,SocketFlags.None,serverEndPoint);
    buf=new byte[BUF_SIZE];
    EndPoint remoteEndPoint=new IPEndPoint(IPAddress.Any,0);
    try{
     int receive=clientSocket.ReceiveFrom(buf,ref remoteEndPoint);
     string strReceive=Encoding.ASCII.GetString(buf,0,receive);
     Console.WriteLine("echoed from server: {0} message:{1}",remoteEndPoint,strReceive);
    }catch(SocketException e){
     Console.WriteLine(e.Message);
    }
   }//while
  }
 }
}
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