1. socket()
2. bind()
3. accept()
4. listen()
5. connect()
6. close()

(10 points) For each of the arguments and return value in the socket() call below, briefly explain their meaning for the socket being opened.

int sock;
sock = socket(AF_INET, SOCK_STREAM, 0);

(10 points) For each of the arguments and return value in the connect() call below, briefly explain their meaning for the connection being established.

int res;
res = connect(sock, (struct sockaddr *) saddr_in, sizeof(saddr_in));

(10 points) Below is output from the hello_server program in the course notes. Why does the port change from client to server?

#> ./hello_server
Listening On: 127.0.0.1:1845
Connection From: 127.0.0.1:42555
Read from client: hello
Sending: Hello 127.0.0.1:42555
Go Navy! Beat Army
Closing socket

(10 points) Consider the code loop for handling client sockets: Can this program handle multiple clients simultaneously? That is, if multiple clients are connected, will the server be able to services all sockets when data is available? Explain.

char buf[BUF_SIZE];
int sockets[NUMSOCKS], i,n;
//iterate over all open sockets
for(i=0;i < NUMSOCKS; i++){
  if(i>0){
    //read from socket
    n = read(sockets[i], buf, BUF_SIZE);
    //socket closed
    if(n<0){
      close(sockets[i]);
      sockets[i] = -1;
    }

    //echo back
    write(sockets[i], buf, n);
  }
 }