Implement a Simple Packet Filter in C

Implement a C program with a filter_packet() function.

Requirements:

• Define a simple packet structure containing protocol, src_ip, dst_ip, src_port, dst_port
• Implement filter_packet() that returns match or no-match based on criteria
• Support filtering by protocol (TCP=6, UDP=17, ICMP=1)
• Support filtering by destination port (e.g., 80 for HTTP)
• Create at least 4 sample packets with different protocols and ports
• Print match/no-match for each packet against each rule
• Show the logic in clear if/else or switch statements
• Document what a real BPF program would look like in the kernel

Success Criteria:

• filter_packet() correctly matches TCP port 80 and ICMP
• Both matched and unmatched packets are shown
• Rules are documented with comments
• Output contains the keywords: filter, match, packet, port