5.10TCP Client Server

1. Experiment 4-4:TCP Client Server

• Experimental Purpose:

Familiarity with TCP client server programming

?

• Experimental requirements:

1. Implement TCP Client Server Echo program

2, transmission information requirements are as follows

(1) Try to send or receive a packet in C language structure

(2) Run the server on the Development Board, the customer service side runs in Ubuntu 12.04, Packet Analysis TCP protocol

?

• Experimental steps:

1. Server-side

#include <stdlib.h>?

#include <stdio.h>?

#include <errno.h>?

#include <string.h>?

#include <netdb.h>?

#include <sys/types.h>?

#include <netinet/in.h>?

#include <sys/socket.h>?

?

#define PortNumber 3333//The port number of the server and the port number of the client must be equal

?

int main (int argc, char *argv[])?

{?

int sockfd,new_fd;?

struct sockaddr_in server_addr;?

struct sockaddr_in client_addr;?

int sin_size;?

int nbytes;

Char buffer[1024];

?

?

/* Start building SOCKFD descriptors on server side */?

if ((Sockfd=socket (af_inet,sock_stream,0)) ==-1)//Af_inet:ipv4; Sock_stream:tcp

{?

fprintf (stderr, "Socket error:%s\n\a", Strerror (errno));?

Exit (1);?

}?

?

/* Server-side populated sockaddr structure */?

Bzero (&server_addr,sizeof (struct sockaddr_in)); Initialize, set 0

server_addr.sin_family=af_inet;???????? Internet

Server_addr.sin_addr.s_addr=htonl (Inaddr_any);//(Convert Long data on this machine to long data on the network) and any host communication?//inaddr_any Represents data that can receive any IP address, which is bound to all IP

Server_addr.sin_port=htons (portnumber);???? (Convert short data on this machine to short data on the network) port number

?

/* Bundle SOCKFD Descriptor to IP address */?

if (bind (SOCKFD, struct sockaddr *) (&SERVER_ADDR), sizeof (struct sockaddr)) ==-1)?

{?

fprintf (stderr, "Bind error:%s\n\a", Strerror (errno));?

Exit (1);?

}?

?

/* Set the maximum number of clients allowed to connect */?

if (Listen (sockfd,5) ==-1)?

{?

fprintf (stderr, "Listen error:%s\n\a", Strerror (errno));?

Exit (1);?

}?

?

while (1)?

{?

/* Server blocked until client program establishes a connection */?

sin_size=sizeof (struct sockaddr_in);?

if ((New_fd=accept (SOCKFD, (struct sockaddr *) (&CLIENT_ADDR), &sin_size)) ==-1)?

{?

fprintf (stderr, "Accept error:%s\n\a", Strerror (errno));?

Exit (1);?

}?

fprintf (stderr, "Server get connection from%s\n", Inet_ntoa (CLIENT_ADDR.SIN_ADDR)); Converts a network address into a. String

?

if ((Nbytes=read (new_fd,buffer,1024)) ==-1)//Here can be written as if ((Nbytes=recv (new_fd,buffer,1024,0)) ==-1)?

{?

fprintf (stderr, "Read error:%s\n", Strerror (errno));?

Exit (1);?

}

buffer[nbytes]= ' + ';

printf ("Server received%s\n", buffer);

?

/* This communication is over.

Close (NEW_FD);?

/* Cycle the next one */?

}?

?

/* End communication */?

Close (SOCKFD);?

Exit (0);?

}?

?

???? 2. Send student information on client and receive echo result

#include <stdlib.h>?

#include <stdio.h>?

#include <errno.h>?

#include <string.h>?

#include <netdb.h>?

#include <sys/types.h>?

#include <netinet/in.h>?

#include <sys/socket.h>?

?

#define PortNumber 3333

?

int main (int argc, char *argv[])?

{?

int sockfd;?

Char buffer[1024];?

struct sockaddr_in server_addr;?

struct hostent *host;?

?

? ? ? ? /* Use hostname to query the host name */

if (argc!=2)?

{?

fprintf (stderr, "usage:%s hostname \a\n", argv[0]);?

Exit (1);?

}?

?

if ((Host=gethostbyname (argv[1))) ==null)?

{?

fprintf (stderr, "GetHostName error\n");?

Exit (1);?

}?

?

/* Client starts to build the SOCKFD descriptor */?

if ((Sockfd=socket (af_inet,sock_stream,0)) ==-1)//af_inet:internet; Sock_stream:tcp

{?

fprintf (stderr, "Socket error:%s\a\n", Strerror (errno));?

Exit (1);?

}?

?

/* Client program fills the data on the server * *?

Bzero (&server_addr,sizeof (SERVER_ADDR)); Initialize, set 0

server_addr.sin_family=af_inet;?????//IPV4

Server_addr.sin_port=htons (portnumber);//(Convert short data on this machine to short data on the network) port number

server_addr.sin_addr=* (struct in_addr *) host->h_addr); IP Address

?

/* Client Initiating connection request */?

if (Connect (SOCKFD, struct sockaddr *) (&SERVER_ADDR), sizeof (struct sockaddr)) ==-1)?

{?

fprintf (stderr, "Connect error:%s\a\n", Strerror (errno));?

Exit (1);?

}?

?

/* Connection succeeded */?

printf ("Please input char:\n");

?

/* Send data */

Fgets (Buffer,1024,stdin);?

Write (Sockfd,buffer,strlen (buffer)); This can be written as send (Sockfd,buffer,strlen (buffer), 0);

?

/* End communication */?

Close (SOCKFD);?

Exit (0);?

}?

?

?

?

3, the server receives information, display and Echo

?

???? 4. Cross-Compile the server and run it through NFS shared copy to the Development Board

?

5, compile the customer service side, directly on Ubuntu 12.04 run

?

6, the test client and server can transfer student information through TCP normally

?

?

?

?

?

?

?

IP for server and client:

?

Experiment Experience:

???? is a TCP type of connection-based communication, which implements a server-side: Development Board, and a client PC host. The exchange of information between the two. The above is my realization. The whole process was very smooth. Thank you.

5.10TCP Client Server