我是套接字编程的新手，我有一个试图连接到同一台计算机上的服务器的客户端。但是服务器在 bind 或 accept 之后卡在那里——因为 bind 似乎是正确的但没有输出。我知道服务器可以正常工作，因为另一个客户端可以很好地连接，而且客户端似乎已经做到了。是什么导致服务器看不到这个传入连接？我已经无计可施了。
而且我不习惯在 Mac 上编程，所以如果我犯了一些愚蠢的错误，非常感谢您的耐心等待。
我的代码如下:
server.cpp
using namespace std;
#include<iostream>
#include <netinet/in.h>
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#define PORT 8888
#define BACKLOG 20
//#define DEST_IP "127.0.0.1"
int process_conn_server(int s)
{
ssize_t size =0;
char buffer[1024];
for( ; ; )
{
size = read(s,buffer,1024);
if(size == 0)
{
return 0;
}
}
sprintf(buffer, "%d bytes altogether\n", (int)size);
write(s, buffer,strlen(buffer)+1);
return 0;
}
int main(int argc,char *argv[])
{
//cout<<"?";
int ss, sc, r, err;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
int opt=1;
pid_t pid;
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
server_addr.sin_port = htons(PORT);
ss = socket(AF_INET, SOCK_STREAM, 0);
if(ss<0)
{
cout<<"[process infro]socket error"<<endl;
return -1;
}
cout<<"[process infro]socket successful"<<endl;
r = setsockopt(ss, SOL_SOCKET,SO_REUSEADDR, (void*)&opt,sizeof(opt));
if (r == -1)
{
perror("setsockopt(listen)");
return 0;
}
cout<<"[process infro]sockopt successful"<<endl;
cout<<"?";
err = bind(ss, (struct sockaddr*) &server_addr, sizeof( server_addr));
cout<<"err";
if(err < 0)
{
cout<<"[process infro]bind error"<<endl;
return -1;
}
cout<<"[process infro]bind successful";
err=listen(ss, BACKLOG);
if(err <0)
{
cout<<"[process infro]listen error"<<endl;
return -1;
}
cout<<"[process infro]lisen successful";
for( ; ; )
{
int addrlen = sizeof(struct sockaddr);
sc = accept(ss, (struct sockaddr*)&client_addr, (socklen_t *)&addrlen);
if(sc < 0)
{
continue;
}
pid = fork();
if (pid == 0)
{
close(ss);
process_conn_server(sc);
}
else
{
close(sc);
}
}
//opt=0;
//setsockopt(ss,SOL_SOCKET,SO_REUSEADDR,(void*)&opt,sizeof(len));
}
客户端.cpp
using namespace std;
#include<iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <time.h>
#include <arpa/inet.h>
#include <fstream.h>
#define PORT 8888
#define DEST_IP "127.0.0.1"
void process_conn_client(int s)
{
ssize_t size = 0;
char buffer[1024];
//read from the file to be sent
fstream outfile("programm.txt",ios::in|ios::out);
if (outfile.fail())
{
printf("[process infro]cannot open the file to be sent\n");
return ;
}
printf("[process infro]successfully open the file to be sent\n");
while(!outfile.eof())
{
outfile.getline(buffer,1025,'\n');
write(s,buffer,1024);
size = read(s, buffer, 1024);
if(size = 0)
{
return ;
}
//write to the server
write(s,buffer,size);
//get response from the server
size=read(s,buffer,1024);
write(1,buffer,size);
}
outfile.close(); //关闭文件
}
int main(int argc,char *argv[])
{
int s;
struct sockaddr_in server_addr;
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = inet_addr(DEST_IP);
server_addr.sin_port = htons(PORT);
s = socket(AF_INET, SOCK_STREAM, 0);
if(s < 0)
{
cout<<"[process infro]socke error"<<endl;
return -1;
}
cout<<"[process infro] socket built successfully\n";
//inet_pton(AF_INET, argv[1], &server_addr.sin_addr);
connect(s, (struct sockaddr*)&server_addr, sizeof(struct sockaddr));
cout<<"[process infor] connected\n";
process_conn_client(s);
close(s);
return 0;
}
最佳答案
这可能是无关的....但它不适合评论...
在你的服务器中你这样做:
int process_conn_server(int s)
{
ssize_t size =0;
char buffer[1024];
for( ; ; )
{
//继续读直到read返回0
size = read(s,buffer,1024);
if(size == 0)
{
return 0;
}
}
sprintf(buffer, "%d bytes altogether\n", (int)size);
write(s, buffer,strlen(buffer)+1);
return 0;
}
在你的客户中你这样做:
void process_conn_client(int s)
{
ssize_t size = 0;
char buffer[1024];
//read from the file to be sent
fstream outfile("programm.txt",ios::in|ios::out);
if (outfile.fail())
{
printf("[process infro]cannot open the file to be sent\n");
return ;
}
printf("[process infro]successfully open the file to be sent\n");
while(!outfile.eof())
{
outfile.getline(buffer,1025,'\n');
//写入服务器？
write(s,buffer,1024);
//从服务器读取？
size = read(s, buffer, 1024);
if(size = 0)
{
return ;
}
//write to the server
write(s,buffer,size);
//get response from the server
size=read(s,buffer,1024);
write(1,buffer,size);
}
outfile.close();
}
由于您的变量名称，这有点难以理解，但看起来您的客户端假设您的服务器将针对接收到的每个数据 block 发回响应，但事实并非如此。您的服务器似乎没有将接受的套接字更改为非阻塞，因此它将阻塞读取调用，直到有一些数据要读取(它永远不会得到 0)...
您确定它在此之前失败了吗？你有一些示例输出吗？
此外，在您接受的调用中，您传递了 addrlen...
int addrlen = sizeof(struct sockaddr);
我认为这应该是:
int addrlen = sizeof(struct sockaddr_in); /* sizeof(client_addr) */
关于c++ - 套接字编程(服务器和客户端在同一台计算机上)连接有问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5662731/