portal

Portal

⚠️ Under active development!

Portal is a domain name server written in Go. Portal is used by Void to answer (and block) DNS queries.

Features

• Recursion and Forwarding (Iterative in progress)
• Caching and auto renewing of RRs
• Filter engine (in progress)
• Custom RRs
• Structured logging
• Metrics collection
• ...

TODOs

General

• [WIP] How should we collect metrics / statistics which can be shown in the web interface of void?
• [TODO] Implement mechanism to return FORMERR when unpacking a message (prior to handling). Maybe move the unpacking into the handling func to be able to handle these kind of errors better and in a centralized place. (See OPT record)
• [TODO] Figure out a way to handle EDNS Options with access to some core components like cache, etc.

Caching

Partial lookup

We need to support lookup of partial domain names: We currently do the following:

• Check if we cached the whole domain name, e.g. example.com
• If we did, return requested RR

If we recursively resolve a domain name and encounter a NS record without any glue records we always start to resolve the domain name of the NS record from root (.). Instead we should lookup the cache if we have partial stored records of NS RRs.

Multiple records

A single node at domain-name should support multiple RRs at class and type. This feature comes with many implications:

• Which of these RRs do we return when looking up the node: All of them or only one? And if only one - which one?
• How do we calculate the Expiry / TTl when we return multiple RRs?
• More?

RFCs

• Finalize Master Files Parsing RFC 1035
• IN-ADDR.ARPA domain RFC 1035
• Message compression RFC 1035
• Implement functions RFC 5001
• Implement functions RFC 6975

RFS to implement

• RPZs DRAFT Vixie DNS RPZ
• LOC RR RFC 1876
• Incremental Zone Transfer in DNS RFC 1995

Supported RFCs

• Domain Names - Concepts and Facilities RFC 1034
• Domain Names - Implementation and Specification RFC 1035
• Serial Number Arithmetic RFC 1982
• Extension Mechanisms for DNS (EDNS(0)) RFC 6891

Usage

Standalone

To use the server as a standalone DNS server, follow these steps:

1. Clone the repository
2. Build the binary via go build
3. Run the binary with ./portal

Library

import (
    "fmt"
    "os"

    "github.com/go-void/portal/pkg/config"
    "github.com/go-void/portal/pkg/server"
)

func main() {
    // Setup config
    c, err := config.Read("path/to/config.toml")
    if err != nil {
        exit(err)
    }

    // Validate config
    err = c.Validate()
    if err != nil {
        exit(err)
    }

    // Create new server
    s := server.New(c)

    // Optionally provide custom implementations for different components via
    err = s.Configure()
    if err != nil {
        exit(err)
    }

    // Run the server
    err = s.Run()
    if err != nil {
        exit(err)
    }

    // This blocks until the server is shutdown
    s.Wait()
}

func exit(err error) {
    fmt.Println(err)
    os.Exit(1)
}