| Algorithm Steps:
Step 1: start
Step 2: Read peer one’s IP, Port ID and peer two’s IP and port ID
Step 3: Create a socket with address family PF_INET type SOCK_DGRAM and default protocol.
Step 4: Initialize the socket and set its attribute set required port no.
Step 5: Connect to server using connect () function to initiate the request.
Step 6: If command line argument count equal to 4 then send the message to server.
Step 7: Receive the string from the server and print it at the console.
Step 8: stop.
C Program To Implement Peer to Peer connection using udp
include
#include
#include
#include
#include
#include
#include
#include
#define MAXBUF 1024
#define MY_PORT 9998
#define PEER_PORT 9999
#define MAXIP 16 /* XXX.XXX.XXX.XXX */
char buffer[MAXBUF];
/*--------------------------------------------------------------------*/
/* SetAddress */
/* */
/* Fill Addr with info from XXX.XXX.XXX.XXX:XXXXX format. */
/*--------------------------------------------------------------------*/
int SetAddress(char* Composite, struct sockaddr_in *Addr)
{ int i;
char IPAddress[MAXIP];
bzero(Addr, sizeof(*Addr));
Addr->sin_family = AF_INET;
for ( i = 0; Composite[i] != ':' && Composite[i] != 0 && i < MAXIP; i++ )
IPAddress[i] = Composite[i];
IPAddress[i] = 0;
if ( Composite[i] == ':' )
Addr->sin_port = htons(atoi(Composite+i+1));
else
Addr->sin_port = 0;
if ( *IPAddress == 0 )
{
Addr->sin_addr.s_addr = INADDR_ANY;
return 0;
}
else
return ( inet_aton(IPAddress, &Addr->sin_addr) == 0 );
}
/*--------------------------------------------------------------------*/
/* main */
/* */
/* Open socket, connect and receive messages */
/*--------------------------------------------------------------------*/
int main(int Count, char *Strings[])
{ int sd;
struct sockaddr_in addr;
if ( Count < 3 || Count > 4 )
{
printf("usage: coupled-peer []\n");
exit(0);
}
if ( (sd = socket(PF_INET, SOCK_DGRAM, 0)) < 0 )
{
perror("Socket");
exit(errno);
}
if ( SetAddress(Strings[1], &addr) != 0 )
{
perror(Strings[1]);
exit(errno);
}
if ( bind(sd, (struct sockaddr *)&addr, sizeof(addr)) != 0 )
{
perror("Bind");
exit(errno);
}
if ( SetAddress(Strings[2], &addr) != 0 )
{
perror(Strings[2]);
exit(errno);
}
if ( connect(sd, (struct sockaddr *)&addr, sizeof(addr)) != 0 )
{
perror("Connect");
exit(errno);
}
if ( Count == 4 )
send(sd, Strings[3], strlen(Strings[3]), 0);
while (1)
{ int bytes_read;
bzero(buffer, sizeof(buffer));
bytes_read = recv(sd, buffer, sizeof(buffer), 0);
if ( bytes_read > 0 )
{
printf("Msg: %s\n", buffer);
sleep(1);
send(sd, buffer, bytes_read, 0);
}
}
close(sd);
return 0;
}
SAMPLE INPUT OUTPUT:
$ gcc peer.c -o peer.exe
$ peer.exe 127.0.0.1:5000 127.0.0.1:5000 hai
Msg: hai
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