The entire project stands under the copyright of University Politehnica of Bucharest, PCOM 2023, being a graded assignment. The implementation uses Miniet for simulating the network in which the router operates. The implementation is targeted at constructing the dataplane of a router which is responsible with forwarding. The following components are implemented:
- Forwarding
- LPM (Longest Prefix Match)
- ARP
- ICMP
- Start Mininet topology:
sudo python3 topo.py
# topology is considered as follows:
host0 host2
\ /
router0 ------- router1
/ \
host1 host3
- Start router:
make run_router0
make run_router1
- Commands for clients:
ping, arping, netcat
Located and described in include dir.
- check Layer2 data <=> packet has router or broadcast as destination
- chech packet type: ARP / ICMP
- verfiy Checksum & TTL
- modify IP header (TTL & Checksum) and Ethernet header (detination & source)
- packet reconstruction:
ETH_HDR | IP_HDR | PAYLOAD=> sent to next hop
- initialize with parse_trie() which creates new nodes in trie for each entry in routing table
- address addition works on binary tree model
- representation: address "addr/len" = firest len bits in binary form of addr
- router can interpret REQUEST/REPLY
- REPLY: cache mac address recieved and send packets waiting for that address
- REQUEST: if router is destination, send ARP REPLY
- send ARP REQUEST if the mac address asociated with the destination ip of the packet recieved isnt's known and add packets with that target to a waiting list
- send ARP REPLY if router is target
- if router is destination of icmp, create and send icmp_reply()
- TIMEOUT if TTL < 2
- DESTINATION UNREACHABLE if destination can't be found in routing table