我将以下缓冲区存储在二维字符缓冲区中：
char buff1[][3]= {{0xff , 0xfd, 0x18},{0xff , 0xfd, 0x1e},{0xff , 0xfd, 0x1d}}; // server side
char buff2[][3] = {{0xff,0xfc,0x1e},{0xff , 0xfc, 0x1d},{0xff , 0xfc, 0x18}}; // client side
当从服务器发送三个字符中的每一个时，我会收到相应的顺序响应 客户。我想知道，如果存储的缓冲区大小可变，应该做出哪些更改。 也就是说，如果buff1 [0] [0]是0xff，0xfd，0x18,0xff，0xfd，0x21，我仍然希望将消息分成3部分。 这是我需要的流程：
Server Sends ---> 0xff 0xfd 0x18
Client Responds ---->0xff 0xfc 0x18
Server sends ---> 0xff 0xfd 0x21
Client Responds ---> 0xff 0xfc 0x21
此外，我尝试使用套接字编程发送这些缓冲区，但是在发送前三个缓冲区后我得到了一个空的recbuff。以下是我的代码：
//client
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/telnet.h>
#include <unistd.h>
#include <netdb.h>
char buff2[][3] = {{0xff,0xfc,0x1e},{0xff , 0xfc, 0x1d},{0xff , 0xfc, 0x18}};
void read (int sock)
{
char buffer[256];
/* Now read server response */
memset(buffer, 0, sizeof(buffer));
int n = recv( sock, buffer, 255, 0 );
if (n < 0)
{
perror("ERROR reading from socket");
return;
}
printf("\n%d bytes received buffer is: %s", n, buffer);
}
void mwrite (int sock, char * buf, int size)
{
int n = send( sock, buf, size, 0 );
if (n < 0)
{
perror("ERROR writing to socket");
return;
}
printf("Bytes Sent: %d\n", n);
}
int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server1;
char buffer1[256];
if (argc < 3)
{
fprintf(stderr,"usage %s hostname port\n", argv[0]);
return(0);
}
portno = atoi(argv[2]);
/* Create a socket point */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
{
perror("ERROR opening socket");
return(1);
}
server1 = gethostbyname(argv[1]);
if (server1 == NULL)
{
fprintf(stderr,"ERROR no such host \n");
exit(0);
}
bzero((char *) &serv_addr , sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server1->h_addr, (char*)&serv_addr.sin_addr.s_addr, server1->h_length);
serv_addr.sin_port = htons( portno );
/*Connect to server*/
if (connect( sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr) ) < 0)
{
perror("ERROR connecting");
return(1);
}
printf("Recieving Buffer 1 from Server side");
bzero(buffer1,256);
int i =0;
while(i < 5)
{
n= read(sockfd,buffer1,sizeof(buffer1));
if(n<0)
printf("ERROR reading in socket %d len %d", n, sizeof(buffer1));
n= write(sockfd,buff2,sizeof(buff2));
if(n<0)
printf("ERROR writing in socket %d len %d", n, sizeof(buff2));
printf("\nSent Buffer2 (WON'T TERMINAL TYPE) from client side");
i++;
}
return(0);
}
服务器端：
//a simple echo server
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/telnet.h>
#include <unistd.h>
char buff1[][3]= {{0xff , 0xfd, 0x18},{0xff , 0xfd, 0x1e},{0xff , 0xfd, 0x1d}};
char recbuf[1024];
void mwrite (int sock, char * buf, int size)
{
int n = send( sock, buf, size, 0 );
if (n < 0)
{
perror("ERROR writing to socket");
return;
}
}
void read (int sock)
{
char buffer[256];
/* Now read client response */
memset(buffer, 0, sizeof(buffer));
int n = recv( sock, buffer, 255, 0 );
if (n < 0)
{
perror("ERROR reading from socket");
return;
}
for (int i = 0; i < n; i++)
printf("%2x ", buffer[i]);//printing ascii characters
printf("\n");
}
int main(int argc , char *argv[] )
{
int sockfd , newsockfd , portno;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
int n;
sockfd = socket(AF_INET , SOCK_STREAM , 0);
if (sockfd < 0 )
{
perror("Error opening socket ");
exit(1);
}
/* Initialize socket structure */
bzero((char *) &serv_addr , sizeof(serv_addr));
portno = atoi(argv[1]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY ;
serv_addr.sin_port = htons(portno);
/* Now bind the host address using client */
if(bind(sockfd, (struct sockaddr *) &serv_addr , sizeof(serv_addr)) <0)
{
perror("Error on binding");
exit(1);
}
if(listen(sockfd,5)<0)
{
perror("Error on listen");
exit(1);
}
int k = 1;
int count = 1;
clilen = sizeof(cli_addr);
newsockfd = accept(sockfd,(struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0)
{
perror("ERROR on accept");
exit(1);
}
printf("Server Sending (DO TERMINAL TYPE)\n");
while(1)
{int i = 0;
while ((n = write(newsockfd,buff1,sizeof(buff1)))>0)
{
printf("Server Sent query to Client %d:%hhX %hhX %hhX\n", k , buff1[count][0], buff1[count][1], buff1[count][2]);
n = read(newsockfd, recbuf , sizeof(recbuf));
printf("Value of n:%d\n",n);
printf("Size of RecBuf:%d\n",sizeof(recbuf));
printf("Server received response from Client: %hhX %hhX %hhX\n\n", recbuf[i+0], recbuf[i+1], recbuf[i+2]);
i = i+3 ;
k++;
count = k % 3;
}
if(n < 0)
{
perror("Error writing to socket");
exit(1);
}
}
close(sockfd);
return(0);
}
输出：
Client Side :
./single_client 127.0.0.1 5000
Recieving Buffer 1 from Server side
Sent Buffer2 (WON'T TERMINAL TYPE) from client side
Sent Buffer2 (WON'T TERMINAL TYPE) from client side
Sent Buffer2 (WON'T TERMINAL TYPE) from client side
Sent Buffer2 (WON'T TERMINAL TYPE) from client side
Sent Buffer2 (WON'T TERMINAL TYPE) from client side
Server Side :
./single_sample 5000
Server Sending (DO TERMINAL TYPE)
Server Sent query to Client 1:FF FD 1E
Value of n:9
Size of RecBuf:1024
Server received response from Client: FF FC 1E
Server Sent query to Client 2:FF FD 1D
Value of n:9
Size of RecBuf:1024
Server received response from Client: FF FC 1D
Server Sent query to Client 3:FF FD 18
Value of n:9
Size of RecBuf:1024
Server received response from Client: FF FC 18
Server Sent query to Client 4:FF FD 1E
Value of n:9
Size of RecBuf:1024
Server received response from Client: 0 0 0 // want FF FC 1E
Server Sent query to Client 5:FF FD 1D
Value of n:9
Size of RecBuf:1024
Server received response from Client: 0 0 0 // should get FF FC 1D
Server Sent query to Client 6:FF FD 18
Value of n:-1
Size of RecBuf:1024
Server received response from Client: 0 0 0 // should get FF FC 18
基本上在客户端的响应中我对所有回复都有0xff和0xfc常量，唯一的区别是第三个字符根据来自server的请求而改变。提前谢谢
答案 0 :(得分：0)
您的程序中存在许多问题。
首先，在两种尺寸中，您使用以下方式编写：
n = write(newsockfd,buff1,sizeof(buff1))
那是在每次写入时，当你说你只想发送3个
时，你会发送 9 个字符为了让你更难理解会发生什么，你在控制台上写下而不是你发送的内容，但是你应该发送的内容
因此，首先正确发送您要发送的3个字符（对于服务器）：
n = write(newsockfd, buff1[count], 3);
请显示您的所作所为！
一旦完成，就像你做客户端一样测试服务器端的参数（不是很难...），并显示客户端发生的事情。
最后，您应该尝试在最后或您的程序中使用graceful shutdown，但我必须承认它是套接字的更高级用法