Document IPv4 Protocol - Value 5

[LSantha]

IPv4 Protocol

Document the IPv4 Protocol JNode concept in the wiki.

Value: 5

Concept Summary

IPv4 packet processing with fragment reassembly. The IPv4 protocol implementation handles packet routing, fragmentation, and reassembly, forming the foundation of JNode's network stack.

Key Files

• net/src/net/org/jnode/net/ipv4/IPv4Protocol.java
• net/src/net/org/jnode/net/ipv4/IPv4Header.java

Occurrences

~150 references in IPv4 package

Wiki Status

NOT documented

Bridges

Network layer, Fragmentation, Routing

Instructions

Skill to Use

Use the [[update-wiki|update-wiki skill]] (load with skill({ name: "update-wiki" })) for understanding JNode internals.

Context Research

Study IPv4Protocol.java to understand packet processing. Review IPv4Header.java for header parsing and construction. Research how fragmentation and reassembly work, and how routing decisions are made.

Update index.md

• Pages table: Add entry for IPv4-Protocol.md
• Concepts → Pages table: Add "IPv4 Protocol" mapping to [[IPv4-Protocol]]
• Source Path → Pages table: Add mappings for net/src/net/org/jnode/net/ipv4/
• Task Routing table: Add relevant task route(s)

Task Routing Suggestions

1. Network debugging: IPv4 is central to network operations
2. Routing issues: Understanding IPv4 routing is key
3. Packet processing: IPv4 handles packet fragmentation

Wiki Page Structure

# IPv4 Protocol

> IPv4 packet processing with fragment reassembly.

## Overview
2-3 paragraph explanation of IPv4 protocol implementation, packet processing, and how fragmentation/reassembly work.

## Key Components
| Class / File | Role |
|---|---|
| `net/src/net/org/jnode/net/ipv4/IPv4Protocol.java` | IPv4 protocol implementation |
| `net/src/net/org/jnode/net/ipv4/IPv4Header.java` | IPv4 header handling |

## How It Works
Explanation of how IPv4 packets are processed, how fragmentation works, and how reassembly is performed.

## Gotchas & Non-Obvious Behavior
- Fragment reassembly requires buffering
- TTL handling is critical for loop prevention
- Checksum validation must be careful

## Related Pages
- [[Network-Stack]]
- [[Network-Layer]]
- [[IPv6-Protocol]]

---

Related Concepts: IP, Fragmentation, Reassembly, Routing, Network layer

[LSantha]

/oc Please proceed with this task.

[opencode-agent]

Wiki page created and pushed: https://github.com/LSantha/jnode_ai/wiki/IPv4-Protocol

Issue #64 closed.

opencode session  |  github run

[LSantha]

/oc Please proceed with this task.

[opencode-agent]

The task is already complete - the IPv4 Protocol wiki page was created and pushed in a previous session, and issue #64 was closed.

opencode session  |  github run