Merge branch 'AlexD/lab03' into 'master'

Lab 3 completed also part of lab 2 is here

See merge request !1

lab3/recv.c

@@ -23,28 +23,80 @@ int main(int argc,char** argv) {
 	init(HOST,PORT);
 
 	struct l3_msg t;
+	
+	int output_file = open("recv.data", O_WRONLY | O_APPEND);
+	
+	while (1)
+	{
+		/* Receive the frame from the link */
+		int len = link_recv(&t, sizeof(struct l3_msg));
+		DIE(len < 0, "Receive message");
 
-	/* Receive the frame from the link */
-	int len = link_recv(&t, sizeof(struct l3_msg));
-	DIE(len < 0, "Receive message");
+		/* We have to convert it to host order */
+		uint32_t recv_sum = ntohl(t.hdr.sum);
+		t.hdr.sum = 0;
+		int sum_ok = (simple_csum((void *) &t, sizeof(struct l3_msg)) == recv_sum);
+		/* TODO 2: Change to crc32 */
 
-	/* We have to convert it to host order */
-	uint32_t recv_sum = ntohl(t.hdr.sum);
-	t.hdr.sum = 0;
-	int sum_ok = (simple_csum((void *) &t, sizeof(struct l3_msg)) == recv_sum);
-	/* TODO 2: Change to crc32 */
+		/* Since we are sending messages with a payload of 1500 - sizeof(header), most of the times the bytes from
+		* 30 - 1500 will be corrupted and thus when we are printing or string message "Hello world" we see no probems.
+		* This will be visible when we will be sending a file */
 
-	/* Since we are sending messages with a payload of 1500 - sizeof(header), most of the times the bytes from
-	 * 30 - 1500 will be corrupted and thus when we are printing or string message "Hello world" we see no probems.
-	 * This will be visible when we will be sending a file */
+		printf("[RECV] len=%d; sum(%s)=0x%04hx; payload=\"%s\";\n", t.hdr.len, sum_ok ? "GOOD" : "BAD", recv_sum, t.payload);
 
-	printf("[RECV] len=%d; sum(%s)=0x%04hx; payload=\"%s\";\n", t.hdr.len, sum_ok ? "GOOD" : "BAD", recv_sum, t.payload);
+		/* TODO 3.1: In a loop, recv a frame and check if the CRC is good */
+		if (sum_ok == 0)
+		{
+			/* TODO 3.2: If the crc is bad, send a NACK frame */
+		
+			printf("Frame is busted\n");
+			
+			/* Look in common.h for the definition of l3_msg */
+			struct l3_msg nack;
 
-	/* TODO 3.1: In a loop, recv a frame and check if the CRC is good */
+			/* We set the payload */
+			sprintf(nack.payload, "nnnnnnnn");
+			nack.hdr.len = strlen(nack.payload) + 1;
 
-	/* TODO 3.2: If the crc is bad, send a NACK frame */
+			/* Add the checksum */
+			/* Note that we compute the checksum for both header and data. Thus
+			* we set the checksum equal to 0 when computing it */
+			nack.hdr.sum = 0;
+
+			/* Since sum is on 32 bits, we have to convert it to network order */
+			nack.hdr.sum = htonl(simple_csum((void *) &nack, sizeof(struct l3_msg)));
+
+			/* Send the message */
+			link_send(&nack, sizeof(struct l3_msg));
+
+		} else {
+			/* TODO 3.2: Otherwise, write the frame payload to a file recv.data */
+			printf("Good frame\n");
+
+
+			write(output_file, t.payload, strlen(t.payload));
+			/* Look in common.h for the definition of l3_msg */
+			struct l3_msg ack;
+
+			/* We set the payload */
+			sprintf(ack.payload, "aaaaaaaa");
+			ack.hdr.len = strlen(ack.payload) + 1;
+
+			/* Add the checksum */
+			/* Note that we compute the checksum for both header and data. Thus
+			* we set the checksum equal to 0 when computing it */
+			ack.hdr.sum = 0;
+
+			/* Since sum is on 32 bits, we have to convert it to network order */
+			ack.hdr.sum = htonl(simple_csum((void *) &ack, sizeof(struct l3_msg)));
+
+			/* Send the message */
+			link_send(&ack, sizeof(struct l3_msg));
+			break;
+		}
+	}
+	
 
-	/* TODO 3.2: Otherwise, write the frame payload to a file recv.data */
 
 	/* TODO 3.3: Adjust the corruption rate */
 

lab3/send.c

@@ -20,29 +20,47 @@ int main(int argc,char** argv) {
 	/* Look in common.h for the definition of l3_msg */
 	struct l3_msg t;
 
-	/* We set the payload */
-	sprintf(t.payload, "Hello my World of PC!");
-	t.hdr.len = strlen(t.payload) + 1;
+	while (1)
+	{
+		/* We set the payload */
+		sprintf(t.payload, "Hello my World of PC!");
+		t.hdr.len = strlen(t.payload) + 1;
 
-	/* Add the checksum */
-	/* Note that we compute the checksum for both header and data. Thus
-	 * we set the checksum equal to 0 when computing it */
-	t.hdr.sum = 0;
+		/* Add the checksum */
+		/* Note that we compute the checksum for both header and data. Thus
+		* we set the checksum equal to 0 when computing it */
+		t.hdr.sum = 0;
 
-	/* Since sum is on 32 bits, we have to convert it to network order */
-	t.hdr.sum = htonl(simple_csum((void *) &t, sizeof(struct l3_msg)));
+		/* Since sum is on 32 bits, we have to convert it to network order */
+		t.hdr.sum = htonl(simple_csum((void *) &t, sizeof(struct l3_msg)));
 
-	/* TODO 2.0: Call crc32 function */
+		/* TODO 2.0: Call crc32 function */
 
-	/* Send the message */
-	link_send(&t, sizeof(struct l3_msg));
+		/* Send the message */
 
-	/* TODO 3.1: Receive the confirmation */
+		link_send(&t, sizeof(struct l3_msg));
 
-	/* TODO 3.2: If we received a NACK, retransmit the previous frame */
+		/* TODO 3.1: Receive the confirmation */
+		struct l3_msg response;
+		int len_resp = link_recv(&response, sizeof(struct l3_msg));
+		DIE(len_resp < 0, "Receive message");
 
-	/* TODO 3.3: Update this to read the content of a file and send it as
-	 * chunks of that file given a MTU of 1500 bytes */
+		/* We have to convert it to host order */
+		uint32_t recv_sum_resp = ntohl(response.hdr.sum);
+		response.hdr.sum = 0;
+		int sum_ok_resp = (simple_csum((void *) &response, sizeof(struct l3_msg)) == recv_sum_resp);
+		/* TODO 2: Change to crc32 */
+
+		/* TODO 3.2: If we received a NACK, retransmit the previous frame */
+		if (strchr(response.payload, 'n'))
+		{
+			link_send(&t, sizeof(struct l3_msg));
+		} else break;
+		
+		/* TODO 3.3: Update this to read the content of a file and send it as
+		* chunks of that file given a MTU of 1500 bytes */
+	}
+	
 
 	return 0;
 }