sending message from client to server and vice versa - c

Question

I have the following code for client and server
#include <sys/types.h>
#include <netinet/in.h>
#include <inttypes.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
int socket_fd;
struct sockaddr_in dest;
struct hostent *hostptr;
struct { char head; u_long body; char tail; } msgbuf;
socket_fd = socket (AF_INET, SOCK_DGRAM, 0);
bzero((char *) &dest, sizeof(dest)); /* They say you must do this */
hostptr = gethostbyname(argv[1]);
dest.sin_family = (short) AF_INET;
bcopy(hostptr->h_addr, (char *)&dest.sin_addr,hostptr->h_length);
dest.sin_port = htons((u_short)0x3333);
msgbuf.head = '<';
msgbuf.body = htonl(getpid()); /* IMPORTANT! */
msgbuf.tail = '>';
sendto(socket_fd,&msgbuf,sizeof(msgbuf),0,(struct sockaddr *)&dest,
sizeof(dest));
return 0;
}
server:
#include <sys/types.h>
#include <netinet/in.h>
#include <inttypes.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#include <unistd.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
int socket_fd, cc, fsize;
struct sockaddr_in s_in, from;
struct { char head; u_long body; char tail;} msg;
socket_fd = socket (AF_INET, SOCK_DGRAM, 0);
bzero((char *) &s_in, sizeof(s_in)); /* They say you must do this */
s_in.sin_family = (short)AF_INET;
s_in.sin_addr.s_addr = htonl(INADDR_ANY); /* WILDCARD */
s_in.sin_port = htons((u_short)0x3333);
printsin( &s_in, "RECV_UDP", "Local socket is:");
fflush(stdout);
bind(socket_fd, (struct sockaddr *)&s_in, sizeof(s_in));
for(;;) {
fsize = sizeof(from);
cc = recvfrom(socket_fd,&msg,sizeof(msg),0,(struct sockaddr *)&from,&fsize);
//printsin( &from, "recv_udp: ", "Packet from:");
printf("Got data ::%c%ld%c\n",msg.head,(long) ntohl(msg.body),msg.tail);
fflush(stdout);
}
return 0;
}
I'm looking for a way to change this code so that:
1.The client will send my name to the server and then will receive the server response.
2.On the server side, the server will receive the client name (instead of the current msg structure) and will send back its name.
I'm assuming I should just put my name in the msgbuf.body like this
msgbuf.head = '<';
msgbuf.body = 'liana';
msgbuf.tail = '>';
and delete the
msgbuf.body = htonl(getpid()); line.
or maybe make a new string for my name like this string name="liana";
and put it in the msgbuf.body like this msgbuf.body=name;(???)
is this the right deriction?
for reciving the response of the server I assume it is the same way as it was done for the server
should I add to client something like this?
int socket_fd, cc, fsize; // the socket that we receive to
struct sockaddr_in s_in, from; // decleration of the server and sending
(to the server) struct
fflush(stdout);//to ensure that whatever you just wrote to a file/the console is indeed written out on disk/the console.
bind(socket_fd, (struct sockaddr *)&s_in, sizeof(s_in));// conecting
between
the socket and all the details we entered
for(;;) {//infinite loop
fsize = sizeof(from);//set the size of the socket we resive to
cc = recvfrom(socket_fd,&msg,sizeof(msg),0,(struct sockaddr
*)&from,&fsize);//recive massage using UDP protocol
printf("Got data ::%c%ld%c\n",msg.head,(long) ntohl(msg.body),msg.tail);
//print the whole massage
fflush(stdout);//to ensure that whatever you just wrote to a file/the
console is indeed written out on disk/the console.
}
and just leave it like this without changing anything?
**how can I make the server receive the my name (instead of the current msg
structure)and send it back?
should I send it back using the
sendto(socket_fd,&msgbuf,sizeof(msgbuf),0,(struct sockaddr *)&dest,
sizeof(dest));
line?
**if I cant use the structure anymore how should i change this line?****
any help whould be appreciated,I'm kind of new to C and never worked with the client/server model