packet_forward()

The goal of packet_forward() is to simulate sending a packet from a source node to a destination node, following the routing table entries that were loaded using get_route_info().

The packet will be forwarded step-by-step using each node’s next hop, until it reaches the final destination. Along the way, we also keep track of how many packets and bytes have been forwarded.

For example:

Forwarding packet: nodeA;nodeC;928
Node nodeA sends to node nodeB (cost: 8)
Node nodeB sends to node nodeC (cost: 3)
Node nodeC is the destination. Done forwarding for the packet.
Current packet size: 928 bytes  

How do we do this?

To simulate packet forwarding, we need to:

1. Parse the Packet String:

   • The input format is source;destination;size

   • Use sscanf() to extract all three values from the string.

2. Start from the Source Node:

   • Use find_node() to get the node where the packet begins.

3. Look for the Destination in the Source's Routing Table:

   • Go through the source node’s dest_list to find a route to the final destination.

4. Forward the Packet Step-by-Step:

   • For each hop:

     • Print the step (src sends to nextHop)

     • Increment packets_sent and bytes_sent

     • Move to the next node (using find_node() again)

   • Repeat until you reach the destination.

5. Print Completion Message

   • Confirm that the destination has been reached.

   • Show the final packet size.