Milestone 2: Core DNS Engine & Packet Handling

[lopster568]

Overview

Implement the core DNS packet handling, interception, and forwarding engine. This forms the backbone of the entire system.

Acceptance Criteria

• DNS packet parser for UDP/TCP protocols
• DNS server implementation binding to port 53
• Transparent DNS query interception
• Transaction ID preservation and mapping
• Upstream resolver integration (Google DNS, Cloudflare, Quad9)
• Connection pooling for upstream resolvers
• Timeout and retry logic for upstream queries
• Performance target: <5ms latency overhead
• Support for both UDP (primary) and TCP fallback
• Basic query/response logging
• Unit tests for DNS packet handling
• Integration tests with real DNS queries

Technical Requirements

• Handle concurrent DNS queries efficiently
• Implement proper error handling for malformed packets
• Support IPv4 and IPv6 addresses
• Memory-efficient packet processing
• Graceful handling of upstream resolver failures

Performance Targets

• Process 1000+ queries per second
• Maintain <5ms additional latency
• Handle concurrent connections up to system limits
• Memory usage should scale linearly with concurrent requests

Definition of Done

• DNS server accepts queries on port 53 (UDP/TCP)
• Successfully forwards queries to upstream resolvers
• Preserves all DNS packet integrity
• Passes all unit and integration tests
• Performance benchmarks meet targets
• Code is properly documented

[lopster568]

Study Checklist:

• DNS Protocol & Packet Structure (RFC 1035 + EDNS0) – headers, sections, transaction IDs, flags, and extensions.
• UDP & TCP Socket Programming – binding to port 53, handling IPv4/IPv6, fallback from UDP → TCP.
• Binary Packet Parsing & Serialization – working with raw bytes, endianess, safe parsing of queries/responses.
• Upstream Resolver Integration & Failover – forwarding queries, timeout/retry logic, backup resolvers.
• Concurrency & Event-driven I/O – async I/O models, handling 1000+ QPS efficiently.
• Performance & Benchmarking – measuring latency (<5ms overhead), throughput testing (dnsperf, queryperf).
• Error Handling & Security Basics – malformed packet handling, avoiding open resolver risks, graceful failures.

[lopster568]

testing, performance benchmark can be done later. We are going to focus on the functionality as of now.

[lopster568]

🎃 Hacktoberfest 2025 - Issue Reopened!

Hi contributors! 👋

This issue has been reopened for Hacktoberfest 2025. While the core functionality of Milestone 2 has been implemented, there are important tasks remaining that need community contribution.

📋 Remaining Tasks

1. Performance Benchmarking & Optimization

   • Achieve <5ms latency overhead target
   • Performance profiling and optimization

2. Testing Infrastructure

   • Unit tests for DNS packet handling
   • Integration tests with real DNS queries
   • Test coverage for edge cases and error scenarios

✅ What's Already Done

• ✅ DNS packet parser for UDP/TCP protocols
• ✅ DNS server implementation binding to port 53
• ✅ Transparent DNS query interception
• ✅ Transaction ID preservation and mapping
• ✅ Upstream resolver integration (Google DNS, Cloudflare, Quad9)
• ✅ Connection pooling for upstream resolvers
• ✅ Timeout and retry logic for upstream queries
• ✅ Support for both UDP (primary) and TCP fallback
• ✅ Basic query/response logging

🚀 Getting Started

For Performance Testing:

• Review the DNS engine implementation in internal/dnsengine/
• Set up benchmarking tools (Go benchmarks, profiling)
• Identify bottlenecks and propose optimizations
• Document performance metrics and improvements

For Testing:

• Study the packet handling code
• Create comprehensive unit tests covering happy paths and edge cases
• Develop integration tests using real DNS scenarios
• Ensure tests work with CI/CD pipeline

🎯 Success Criteria

• Performance target of <5ms latency overhead achieved
• Comprehensive test coverage (>80%)
• All tests passing in CI/CD
• Documentation of testing approach and benchmarks

This is a great opportunity to contribute to DNS infrastructure and learn about performance optimization and testing strategies!

Feel free to ask questions below. Happy hacking! 🎉

#hacktoberfest