Attempt 1, filled in some of the relevant sections.

echoserver/echoserver.c

@@ -16,7 +16,9 @@ int main(int argc, char **argv)
     bool quitFlag = true;
     int socketEchoFD;
     int clientEchoFD;
+    int reuseAddrOpt = 1;
     char message[BUFFER_SIZE];
+    int messageBytes;
     struct sockaddr_in serverAddr;
     struct sockaddr_storage clientAddr;
     socklen_t clientSize;
@@ -30,6 +32,9 @@ int main(int argc, char **argv)
         return -1;
     }
     // use the setsockopt function to make the socket accept different configurations
+    // allow for the reuse of the address/bind.
+    setsockopt(socketEchoFD, SOL_SOCKET, SO_REUSEADDR, &reuseAddrOpt, sizeof(reuseAddrOpt));
+    // also need to set the socket to non-blocking using setsockopt?
     // CODE HERE
     // bind the TCP socket to port 8888 / ECHOPORT
     serverAddr.sin_family = AF_INET;
@@ -82,7 +87,7 @@ int main(int argc, char **argv)
             return -1;
         }
         // grab the data from the client, save to message.
-        // NEW CODE HERE
+        messageBytes = recv(clientEchoFD, message, BUFFER_SIZE, MSG_WAITALL);
         // if "01189998811991197253\r\n" is received, then close the server.
         if (strcmp(message, "01189998811991197253\n") == 0 || strcmp(message, "01189998811991197253\r\n") == 0)
         {
@@ -92,6 +97,17 @@ int main(int argc, char **argv)
         }
         // otherwise, repeat/echo back the message to the client.
         // NEW CODE HERE
+        // make sure that the connection is still open before attempting to send.
+        if(messageBytes <= 0)
+        {
+            // this means that the connection is closed, or had another error.
+            return -1;
+        }
+        else
+        {
+            // send back the message over the clientEcho socket.
+            send(clientEchoFD, message, messageBytes, 0);
+        }
         // close the accepted listening socket since it is no longer needed.
         close(clientEchoFD);
     }