⚡ GoDNS - High-Performance, RFC-Compliant Recursive DNS Resolver

A concurrent DNS protocol implementation in Go, featuring non-blocking I/O architecture, RFC1035-compliant message processing, and upstream resolver integration. The implementation demonstrates advanced protocol engineering patterns and distributed systems principles.

Protocol Architecture

Core Implementation Components

• UDP Transport Layer: Non-blocking datagram processing with concurrent goroutine dispatch
• DNS Protocol Layer: RFC1035-compliant message encoding/decoding with compression support
• Resource Record Handler: Polymorphic RR type processing with binary-safe implementations
• Query Propagation: Asynchronous upstream resolver integration with timeout semantics

Protocol Specifications

type DNSHeader struct {
    ID      uint16 // Transaction identifier
    Flags   uint16 // Control flags (QR|Opcode|AA|TC|RD|RA|Z|RCODE)
    QDCount uint16 // Question section cardinality
    ANCount uint16 // Answer section RR count
    NSCount uint16 // Authority section RR count
    ARCount uint16 // Additional section RR count
}

type DNSQuestion struct {
    Name  string  // Domain name sequence
    Type  uint16  // RR type identifier
    Class uint16  // Class identifier
}

type DNSRecord struct {
    Name     string  // Domain name sequence
    Type     uint16  // RR type identifier
    Class    uint16  // Class identifier
    TTL      uint32  // Time-to-live
    RDLength uint16  // RDATA length
    RData    []byte  // Resource data
}

Implementation Architecture

Protocol Processing Pipeline

Message Parser Implementation

• Binary-safe buffer management for DNS wire format
• Domain name label compression/decompression with pointer traversal
• Resource record serialization with length-prefixed encoding
• Transaction ID correlation for asynchronous responses

Network Stack Integration

• UDP socket multiplexing with Go runtime scheduler
• Concurrent query handling via goroutine dispatch
• Configurable upstream resolver interface
• Structured error propagation and logging

Binary Wire Format Specification

DNS Header Structure (96 bits)

Field	Bit Offset	Length	Semantic Definition
ID	0	16	Query identifier for transaction correlation
Flags	16	16	Protocol control bits
QDCOUNT	32	16	Question section cardinality
ANCOUNT	48	16	Answer section RR count
NSCOUNT	64	16	Authority section RR count
ARCOUNT	80	16	Additional section RR count

Message Compression Algorithm

• Label pointer detection with 2-bit discrimination
• Offset-based compression with 14-bit pointer space
• Recursive decompression with cycle detection
• Length-prefixed label encoding

Implementation Capabilities

Protocol Features

• RFC1035-compliant message processing
• Concurrent query handling
• Upstream resolver integration
• Error propagation and recovery
• Domain name compression support

Technical Architecture

• Non-blocking I/O operations
• Concurrent goroutine dispatch
• Binary-safe buffer handling
• Resource lifecycle management

Deployment Configuration

Prerequisites

• Go runtime environment (≥1.18)
• Privileged port binding capabilities
• Network stack access permissions

Binary Compilation

git clone https://github.com/sumitbhuia/GoDNS.git
cd GoDNS
go build -o godns main.go

Process Execution

sudo ./godns  # Requires privileged port binding

Default configuration establishes UDP listener on port 53 with upstream resolver at 8.8.8.8:53.

Protocol Enhancement Specifications

Planned Implementation Extensions

• TCP fallback for truncated responses
• EDNS0 (RFC6891) implementation
• Response cache with LRU eviction
• Extended RR type support
• Security protocol integration

RFC Specifications

Primary Protocol Documentation

• RFC 1035: DNS Implementation and Specification
• RFC 6891: Extension Mechanisms for DNS (EDNS(0))

Technical Proficiencies Demonstrated

• Protocol Engineering
• Distributed Systems Architecture
• Concurrent Programming Patterns
• Binary Protocol Implementation
• Network Stack Integration
• Resource Management
• Error Handling Methodologies

Implementation Contact Vector

📧 Electronic Mail: [email protected]
🐙 Version Control: sumitbhuia
💬 Communication Channel: @bhuia_sumit

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