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GSOC2025IcmpSocket

2025-08-31T05:28:04Z

Aditya: /* Milestones */

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Back to [[Summer_Projects#Google_Summer_of_Code_2025 | GSoC 2025 projects]]

= Project Overview =

* '''Project Name:''' ICMP socket and generate/handle ICMP messages (host/net unreachable)
* '''Student:''' Aditya Ruhela
* '''Mentors:''' Tommaso Pecorella and Alberto Gallegos Ramonet
* '''Google page:'''
* '''Project Goals: Develop an ICMP socket according to LINUX implementation of ICMP SOCK_DGRAM. Currently, for sending ICMP packets, the application has to use a Raw socket. This results in having the user write all the code for adding the headers, the filtering, etc. The proposed ICMP socket aims to offload all this functionality from the user and provide the user with API's required for sending and receiving packets, filtering etc.'''
* '''Repo:''' https://gitlab.com/ADI-ROXX/ns-3-dev

= Milestones =
'''Phase 1: Fix the fragmentation issue in Raw sockets'''
[https://gitlab.com/nsnam/ns-3-dev/-/merge_requests/2486 Merge Request]
* '''Changes made:'''
** '''Forward assembled packets:''' In case of '''raw sockets''', forward the packet up to the '''application''' after the '''re-assembly''', not before that (existing implementation)
** '''Test cases:''' Wrote the test case for '''IPv4''' and '''IPv6 Raw sockets''' that ensure that only a single assembled packet is received. Also, included the test cases for '''Ping application''' with fragmentation.

'''Phase 2: Implementation of the ICMP socket'''
[https://gitlab.com/nsnam/ns-3-dev/-/merge_requests/2527 Merge Request]
* '''Changes'''
** '''ICMP error messages:''' Integrated support for sending '''ICMP Destination Unreachable''' messages from the '''IP layer''' upon packet drop.
** '''ICMP socket:''' Implemented a dedicated '''ICMP socket''', the '''LLD''' of which is similar to that of the '''UDP socket'''.
** '''Features:'''
*** '''ICMP handling:''' The responsibility for processing '''ICMP headers''' is completely offloaded from the application. The new socket no longer sends the '''ICMP header''' to the application (unlike raw sockets). Rather, it uses '''IcmpPacketInfoTag''' for the same.
*** '''New Packet Tag implemented:''' Introduced a new '''IcmpPacketInfoTag''' that stores '''metadata''' about the '''ICMP packet''' received to be sent up to the application.

** '''Tests:''' Added '''unit tests''' for validating ICMP functionality covering almost all of the '''ICMP types''' for received packet ('''echo reply, destination unreachable, time exceeded, etc.''')
** '''Ping application:''' Integrated the novel '''ICMP socket''' in the '''Ping application'''. Allowed for the user to choose whether to send packets via '''ICMP socket''' or via '''Raw Sockets'''.

* '''Limitations and proposed solutions'''
** '''SO_REUSEADDR:''' The novel '''ICMP socket''' does not allow for two sockets on the same node to be bound to the same '''identifier''' even if they are bound to different '''IP addresses'''. This can be solved by using a '''map(identifier -> List of ICMP sockets)''' instead of the current implementation '''map(identifier -> ICMP socket)'''.
** '''Identifier map in Protocol layer:''' The current '''LLD''' of the socket states to store the '''map of used identifiers''' in the '''protocol layer'''. This kind-of pollutes the '''ICMP protocol'''. To solve this, an '''unordered set''' can be stored in the '''IcmpSocketFactory''' object to store all the '''identifiers''' already used for a particular '''node'''.

GSOC2025IcmpSocket

2025-08-30T14:32:27Z