Question

1. Write a C program that prints the default TCP, UDP, and SCTP send and receive buffer sizes and run it on the systems to which you have access.

Answer 1

Solution

Code

#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <strings.h>
int main(int argc, char* argv[])
{
  
  
int socket_fd = socket(AF_INET, SOCK_STREAM, 0);

int receivebuffer;
int length = sizeof(receivebuffer);
int retu = getsockopt(socket_fd, SOL_SOCKET, SO_RCVBUF, &receivebuffer, &length);

int msg;
length = sizeof(msg);
getsockopt(socket_fd, IPPROTO_TCP, TCP_MAXSEG, &msg, &length);
printf("defaults: SO_RCVBUF: %d, TCP_MAXSEG: %d\n", receivebuffer, msg);

struct sockaddr_in serveraddress;
bzero(&serveraddress, sizeof(serveraddress));
serveraddress.sin_family = AF_INET;
serveraddress.sin_port = htons(13);
inet_pton(AF_INET, "127.0.0.1", &serveraddress.sin_addr);
connect(socket_fd, (struct sockaddr*)&serveraddress, sizeof(serveraddress));

length=sizeof(receivebuffer);
getsockopt(socket_fd, SOL_SOCKET, SO_RCVBUF, &receivebuffer, &length);
length = sizeof(msg);
getsockopt(socket_fd, IPPROTO_TCP, TCP_MAXSEG, &msg, &length);
printf("defaults: SO_RCVBUF: %d, TCP_MAXSEG: %d\n", receivebuffer, msg);
return 0;

}

Screenshot of the code

Output

---

all the best