B&D's Networking Lab

8/7/2019 B&D's Networking Lab

1/14

NETWORKING LABASSIGNMENT

NAME:

UNIV. ROLL:

YEAR: 3

RD

STREAM : IT


2/14

IP configuration

In Windows:Steps:1.Start-> Connect to-> Show all network->selectconnection(lan/wireless)2. Rt click on that -> go to Properties3. Click on tcp/ip4 -> click on properties4. New window will pop up , Change ip,subnet,gateway,server address accordingly5. click on OK-> click on CLOSE

IN LINUX:

Command mode:# ifconfig eth0 netmask upEg. # ifconfig eth0 192.168.1.5 netmask 255.255.255.0 up

OR

GUI Mode:$ system-config-network

New window pop up Steps:1. Select the connection(eth0/eth1/wireless etc)2.Change the IP ,Subnet,Gateway , server address as requied3. Click on OK.


3/14

Socket Theory

Socket: An interface between an application process and

transport layerThe application process can send/receive messages

to/from another applicationprocess (local or remote)via a socket.

In Unix jargon, a socket is a file descriptor an integer associated with an openfile

Types of Sockets: Internet Sockets, unix sockets, X.25 sockets etc

Internet sockets characterized by IP Address (4 bytes) and port number (2bytes)

Types of Internet SocketsStream Sockets (SOCK_STREAM) - Connection oriented,

Rely on TCP toprovide reliable two-way connected communication

Datagram Sockets (SOCK_DGRAM) - Rely on UDP , Connection is unreliable

bind() - what port am I on?

Used to associate a socket with a port on the local machine. The port numberis used by the kernel to match an incoming packet to aprocess.

int bind(int sockfd, struct sockaddr *my_addr, int addrlen)sockfd is the socket descriptor returned by socket()my_addr is pointer to struct sockaddr that contains

information aboutyour IP address and port

addrlen is set to sizeof(struct sockaddr)returns -1 on errormy_addr.sin_port = 0; //choose an unused port at randommy_addr.sin_addr.s_addr = INADDR_ANY; //use my IP addrconnect() - Hello! Connects to a remote host


4/14

int connect(int sockfd, struct sockaddr *serv_addr, int addrlen)

sockfd is the socket descriptor returned by socket()serv_addr is pointer to struct sockaddr that contains

information ondestination IP address and portaddrlen is set to sizeof(struct sockaddr)returns -1 on errorAt times, you don't have to bind() when you are using

connect()send() and recv() - Let's talk!The two functions are for communicating over stream

sockets or connecteddatagram sockets.

int send(int sockfd, const void *msg, int len, int flags);sockfd is the socket descriptor you want to send data to

(returned bysocket() or got with accept())

msg is a pointer to the data you want to sendlen is the length of that data in bytesset flags to 0 for nowsent() returns the number of bytes actually sent (may be

less than the

number you told it to send) or -1 on errorsend() and recv() - Let's talk!int recv(int sockfd, void *buf, int len, int flags);sockfd is the socket descriptor to read frombuf is the buffer to read the information len is the

maximum length of the bufferset flags to 0 for nowrecv() returns the number of bytes actually read into the

buffer or -1 onerror

If recv() returns 0, the remote side has closed connection on you

close() - Bye Bye!int close(int sockfd);Closes connection corresponding to the socket descriptor

and frees the


5/14

socket descriptorWill prevent any more sends and recvssocket() -- Get the file descriptorint socket(int domain, int type, int protocol);

domain should be set to AF_INET

type can be SOCK_STREAM or SOCK_DGRAMset protocol to 0 to have socket choose the correct

protocol based on typesocket() returns a socket descriptor for use in later systemcalls or -1 on error.

Q. WAP to add 2 nos. in server passed by client and thenprint the result on client.

Server side

#include#include#include#include#include

int main(){int server_sockfd,client_sockfd;int server_len,client_len;

struct sockaddr_un server_address;struct sockaddr_un client_address;unlink("server_socket");server_sockfd=socket(AF_UNIX,SOCK_STREAM,0);server_address.sun_family=AF_UNIX;strcpy(server_address.sun_path,"server_socket");server_len=sizeof(server_address);bind(server_sockfd, (struct sockaddr

*)&server_address,server_len);listen(server_sockfd,5);

while(1)

{ char ch; int n1,n2,result;

system("clear");printf("Server Waiting...");client_len=sizeof(client_address);client_sockfd=accept(server_sockfd,(struct sockaddr

*)&client_address,


6/14

&client_len);read(client_sockfd,&n1,1);read(client_sockfd,&n2,1);

/* read(client_sockfd,&ch,1);*/result = n1 + n2;

write(client_sockfd,&result,1);close(client_sockfd);}

}

Output:

$ cc addserver.c -o ads.out$ ./ads.out

Client Side

#include#include#include#include#include

int main(){ int sockfd; int len; struct sockaddr_un address; int result,n1,n2; char ch;sockfd=socket(AF_UNIX,SOCK_STREAM,0);address.sun_family=AF_UNIX;strcpy(address.sun_path,"server_socket");len=sizeof(address);result=connect(sockfd, (struct sockaddr

*)&address,len); if(result==-1)

{perror("oops:client1");


7/14

exit(1);}

printf("\nEnter A Number:");scanf("%d",&n1);printf("\nEnter Another Number:");scanf("%d",&n2);fflush(stdin);

/*printf("\nEnter Operator(+,-,*,/ etc.):");scanf("%c",&ch);*/write(sockfd,&n1,1);write(sockfd,&n2,1);

/*write(sockfd,&ch,1);*/read(sockfd,&result,1);printf("\nResult, Addition of two numbers ::

%d",result);close(sockfd);exit(0);

}

output:$ cc addclient.c -o adc.out$ ./adc.outEnter A number: 12

Enter Another number:13Result , Addition of two numbers:: 25$


8/14

Q. WAP in C (socket programming) to make a chatapplication in which two Host(server & client) can passmessage to each other.

#include#include#include#include#include#include#includeint main()

{int server_sd,server_len,client_len,b,a,client_sd;struct sockaddr_in server_addr,client_addr;char ipadd[]={"10.10.76.116"};server_len=sizeof(server_addr);int port=5499;char recvmessg[20],sendmessg[20];server_sd=socket(AF_INET,SOCK_STREAM,0);if(server_sd>=0)printf("socket created successfully\n");

//server_len=sizeof(server_addr);server_addr.sin_family=AF_INET;server_addr.sin_port=htons(port);inet_aton(ipadd,(&server_addr.sin_addr));server_len=sizeof(server_addr);


9/14

b=bind(server_sd,(struct sockaddr*)&server_addr,server_len);

if(b>=0)printf("\nbinded successfully\n\n");listen(server_sd,5);client_len=sizeof(client_addr);a=accept(server_sd,(struct sockaddr

*)&client_addr,&client_len); while(1){

read(a,&recvmessg,20);printf("%s",recvmessg);

printf("\nEnter message for reply: ");gets(sendmessg);write(a,&sendmessg,20);

if(strcmp(recvmessg,"bye")==0){close(server_sd);exit(0);

}}

}

Out put:$cc chat_serv.c o chts.out$./chts.outsocket created successfullybinded successfullyhiEnter message for reply: hello

Wats upEnter message for reply: bye$

Client Side:

#include


10/14

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

int main(){int client_sd,client_len;char ipadd[]={"10.10.76.116"};int port=5499;

char recvmssg[20],sendmssg[20];struct sockaddr_in client_addr;client_sd=socket(AF_INET,SOCK_STREAM,0);if(client_sd>0)printf("socket created successfully");

client_len=sizeof(client_addr);client_addr.sin_family=AF_INET;client_addr.sin_port=htons(port);inet_aton(ipadd,(&client_addr.sin_addr));

connect(client_sd,(struct sockaddr*)&client_addr,client_len);while(1){

printf("\nenter the msg : ");gets(sendmssg);write(client_sd,&sendmssg,20);read(client_sd,&recvmssg,20);puts(recvmssg);

if(strcmp(recvmssg,"bye")==0){close(client_sd);exit(0);}


11/14

}}

Output:$ cc chat_cl.c o chtc.out$ ./chtc.outsocket created successfullyenter the msg : hihelloenter the msg : wats up$

Q. WAP in C (Socket Programming) in Which Client machine ask and

get the date and time from a server machine.

Server Side:

#include#include#include#include#include#include#include#include#include#include#include#include#includestruct sockaddr_in serv_addr,cli_addr;int sockfd,cli_addr_len,connfd,bb;

char buff[1024];time_t ticks;char serv_ip[]={"10.10.76.116"};unsignedshort serv_port=5045;int main(){bzero(&serv_addr,sizeof(serv_addr));


12/14

sockfd = socket(AF_INET,SOCK_STREAM,0);serv_addr.sin_family=AF_INET;serv_addr.sin_port=htons(serv_port);inet_aton(serv_ip,(&serv_addr.sin_addr));bind(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));listen(sockfd,5);cli_addr_len=sizeof(cli_addr);while(1){connfd= accept(sockfd,(structsockaddr*)&cli_addr,&cli_addr_len);ticks=time(NULL);snprintf(buff,(int)

(sizeof(buff)),"%.24s\r\n",ctime(&ticks));write(connfd,buff,(int)(sizeof(buff)));close(connfd);}}

Output:$ cc date_serv.c o dts.out$ ./ dts.out

Client Side:

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


13/14

#include#include#include#include

struct sockaddr_in serv_addr;int client_sd,r,w;int serv_port = 5045;char server_ip[]={"10.10.76.116"};char rcvmsg[1024];int main(int args,char **argv){bzero(&serv_addr,sizeof(serv_addr));if((client_sd=socket(AF_INET,SOCK_STREAM,0))


14/14

}

Output:$ cc date_clt.c o dtc.out$ ./dtc.outTCP ECHO CLINTrecieved msg :Sat Apr 16 21:39:30 2011$

Documents

B&D's Networking Lab