geoipns

GeoIPNS

Make DNS queries to get the geolocation and ASN name of an IP address. You can read the original blog post about why this project exists here.

Usage

Make a TXT query for IP.geoipns to the server to get the location and ASN name of IP in an RFC 1464 compliant format. The model can be easily extended to store arbitrary data about IP subnets using the configuration file.

To build and run,

go get github.com/pulsejet/geoipns && cd $GOPATH/src/github.com/pulsejet/geoipns
dep ensure  # you may skip this step if deps are obtained automatically
go build
./getdata.sh  # write your custom script to get GeoIP data
./geoipns

To query,

$ dig +short @localhost -p5312 -tTXT 3.105.177.255.geoipns
"location=Sydney, NSW, AU"
"asn=Amazon.com, Inc."

Data Structure

Each subnet is stored as an IP range with start and end 128-bit IP addresses. All data points are stored together as an array sorted by the IP address, with a high/low boolean. The data structure is looked up using binary search to find the location of the queried IP address. If a low IP precedes the discovered location, the IP is contained in the corresponding range; if a high IP precedes then the IP is contained in the parent range (if existent). Each data point stores information about the complementary point and the parent range.

Example Data Structure

The following CSV (with proper configuration)

would produce the following data structure (note that all IP addresses are internally represented as 128-bit bytes slices)

Testing

Use go test -v ./... to run automated tests.

Benchmark

Testing GeoIPNS running on an LXC container limited to 4 vCPUs and 4GB RAM on a 24 x Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz machine with PHP7.3 on the same machine for 10000 randomized IPv4 requests gave the following results:

Average 433μs per GeoIPNS request (native DNS client + PHP, different container)
Average 229μs per GeoIPNS request (phpdns, different container)
Average 150μs per GeoIPNS request (singe-threaded C++, same container)
Average 94μs per GeoIPNS request (goroutines, same container)

Docker

Since the GeoLite database cannot be downloaded directly any more, you will have to write your own script replacing getdata.sh to download the GeoIP database as a CSV. The getdata.sh and Dockerfile files are kept in the repository for historical purposes only.

Two environment variables can be set:

• SUFFIX: the DNS suffix to listen on
• INTRANET_CSV_URL: a URL pointing to a CSV file with location entries other than GeoIP2 lite