Bump golang.org/x/net from 0.37.0 to 0.38.0 (#42)

* Bump golang.org/x/net from 0.37.0 to 0.38.0

Bumps [golang.org/x/net](https://github.com/golang/net) from 0.37.0 to 0.38.0.
- [Commits](https://github.com/golang/net/compare/v0.37.0...v0.38.0)

---
updated-dependencies:
- dependency-name: golang.org/x/net
  dependency-version: 0.38.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update packages

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Daniel Carrillo <daniel.carrillo@gmail.com>

.github/workflows/codeql-analysis.yml

@@ -29,21 +29,18 @@ jobs:
       contents: read
       security-events: write
 
-    strategy:
-      fail-fast: false
-
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: install go
-      uses: actions/setup-go@v3
+      uses: actions/setup-go@v5
       with:
         go-version-file: go.mod
         cache: true
 
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
+      uses: github/codeql-action/init@v3
       with:
         languages: go
 
@@ -52,4 +49,4 @@ jobs:
        make build
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2
+      uses: github/codeql-action/analyze@v3

.github/workflows/main.yml

@@ -8,17 +8,19 @@ on:
       - '*'
   pull_request:
 
+concurrency: ${{ github.ref_name }}
+
 jobs:
   tests:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        make: ["lint", "test"]
+        make: ["lint", "unit-test", "integration-test"]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: install go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version-file: go.mod
 
@@ -33,11 +35,11 @@ jobs:
       matrix:
         goosarch: [linux-amd64]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: install go
-        uses: actions/setup-go@v3
+        uses: actions/setup-go@v5
         with:
           go-version-file: go.mod
           cache: true
@@ -61,7 +63,7 @@ jobs:
           sha256sum whatismyip-$RELEASE_VERSION-${{matrix.goosarch}}.tar.gz > whatismyip-$RELEASE_VERSION-${{matrix.goosarch}}.tar.gz.sha256
 
       - name: Release
-        uses: softprops/action-gh-release@v1
+        uses: softprops/action-gh-release@v2
         with:
           body_path: changelog.txt
           files: |

.gitignore

@@ -0,0 +1 @@
+whatismyip

.golangci.yaml

@@ -0,0 +1,64 @@
+version: "2"
+linters:
+  default: none
+  enable:
+    - ineffassign
+    - nakedret
+    - revive
+    - staticcheck
+    - unconvert
+    - unparam
+    - unused
+  settings:
+    revive:
+      confidence: 0.8
+      severity: warning
+      rules:
+        - name: blank-imports
+        - name: context-as-argument
+        - name: context-keys-type
+        - name: dot-imports
+        - name: error-return
+        - name: error-strings
+        - name: error-naming
+        - name: exported
+        - name: increment-decrement
+        - name: var-naming
+        - name: var-declaration
+        - name: package-comments
+        - name: range
+        - name: receiver-naming
+        - name: time-naming
+        - name: unexported-return
+        - name: indent-error-flow
+        - name: errorf
+        - name: empty-block
+        - name: superfluous-else
+        - name: unused-parameter
+        - name: unreachable-code
+        - name: redefines-builtin-id
+    staticcheck:
+      checks:
+        - all
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+issues:
+  max-same-issues: 0
+formatters:
+  enable:
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$

Dockerfile

@@ -1,22 +1,29 @@
-FROM golang:1.21-alpine as builder
+FROM golang:1.24-alpine AS builder
 
 ARG ARG_VERSION
-ENV VERSION $ARG_VERSION
+ENV VERSION=$ARG_VERSION
 
 WORKDIR /app
-
+COPY go.mod .
+COPY go.sum .
+RUN --mount=type=cache,target=/go/pkg/mod/ go mod download -x
 COPY . .
 
-RUN apk add make git upx && make build VERSION=$VERSION \
+FROM builder AS build-dev-app
+# hadolint ignore=DL3018
+RUN --mount=type=cache,target=/go/pkg/mod/ apk --no-cache add make && make build
+
+FROM builder AS build-prod-app
+# hadolint ignore=DL3018
+RUN apk --no-cache update && apk add --no-cache ca-certificates make upx \
+    && update-ca-certificates \
+    && make build \
     && upx --best --lzma whatismyip
 
-# Build final image
+FROM scratch AS dev
-FROM scratch
+COPY --from=build-dev-app /app/whatismyip /usr/bin/
-
+ENTRYPOINT ["whatismyip"]
-WORKDIR /app
+
-
+FROM scratch AS prod
-COPY --from=builder /app/whatismyip /usr/bin/
+COPY --from=build-prod-app /app/whatismyip /usr/bin/
-
-EXPOSE 8080
-
 ENTRYPOINT ["whatismyip"]

LICENSE

@@ -176,7 +176,7 @@
 
    END OF TERMS AND CONDITIONS
 
-   Copyright 2021 Daniel Carrillo
+   Copyright 2024 Daniel Carrillo
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

Makefile

@@ -5,44 +5,40 @@ DOCKER_URL ?= dcarrillo/whatismyip
 .PHONY: test
 test: unit-test integration-test
 
-.PHONY: unit-test
 unit-test:
-	go test -race -short -cover ./...
+	go test -count=1 -race -short -cover ./...
 
-.PHONY: integration-test
 integration-test:
-	go test ./integration-tests -v
+	go test -count=1 -v ./integration-tests
 
-.PHONY: install-tools
 install-tools:
 	@command golangci-lint > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
 		curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(GOPATH)/bin; \
 	fi
 
+	@command $(GOPATH)/revive > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
+		go get -u github.com/mgechev/revive; \
+	fi
+
 	@command $(GOPATH)/shadow > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
 		go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow@latest; \
 	fi
 
-	@command $(GOPATH)/golines > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
-		go install github.com/segmentio/golines@latest; \
-	fi
-.PHONY: lint
 lint: install-tools
 	gofmt -l . && test -z $$(gofmt -l .)
-	golines -l . && test -z $$(golines -l .)
 	golangci-lint run
 	shadow ./...
 
-.PHONY: build
 build:
 	CGO_ENABLED=0 go build -ldflags="-s -w -X 'github.com/dcarrillo/whatismyip/internal/core.Version=${VERSION}'" -o whatismyip ./cmd
 
-.PHONY: docker-build
+docker-build-dev:
-docker-build:
+	docker build --target=dev --build-arg=ARG_VERSION="${VERSION}" --tag ${DOCKER_URL}:${VERSION} .
-	docker build --build-arg=ARG_VERSION="${VERSION}" --tag ${DOCKER_URL}:${VERSION} .
 
-.PHONY: docker-push
+docker-build-prod:
-docker-push: docker-build
+	docker build --target=prod --build-arg=ARG_VERSION="${VERSION}" --tag ${DOCKER_URL}:${VERSION} .
+
+docker-push: docker-build-prod
 ifneq (,$(findstring devel-,$(VERSION)))
 	@echo "VERSION is set to ${VERSION}, I can't push devel builds"
 	exit 1
@@ -52,12 +48,17 @@ else
 	docker push ${DOCKER_URL}:latest
 endif
 
-.PHONY: docker-run
+docker-run: docker-build-dev
-docker-run: docker-build
 	docker run --tty --interactive --rm \
-	-v ${PWD}/test/GeoIP2-City-Test.mmdb:/tmp/GeoIP2-City-Test.mmdb:ro \
+		--publish 8080:8080/tcp \
-	-v ${PWD}/test/GeoLite2-ASN-Test.mmdb:/tmp/GeoLite2-ASN-Test.mmdb:ro -p 8080:8080 \
+		--publish 8081:8081/tcp \
+		--publish 8081:8081/udp \
+		--volume ${PWD}/test:/test \
 		${DOCKER_URL}:${VERSION} \
-		-geoip2-city /tmp/GeoIP2-City-Test.mmdb \
+		-geoip2-city /test/GeoIP2-City-Test.mmdb \
-		-geoip2-asn /tmp/GeoLite2-ASN-Test.mmdb \
+		-geoip2-asn /test/GeoLite2-ASN-Test.mmdb \
-		-trusted-header X-Real-IP
+		-trusted-header X-Real-PortReal-IP \
+		-tls-bind :8081 \
+		-tls-crt /test/server.pem \
+		-tls-key /test/server.key \
+		-enable-http3

README.md

@@ -9,11 +9,13 @@
 - [What is my IP address](#what-is-my-ip-address)
   - [Features](#features)
   - [Endpoints](#endpoints)
+  - [DNS discovery](#dns-discovery)
   - [Build](#build)
   - [Usage](#usage)
   - [Examples](#examples)
     - [Run a default TCP server](#run-a-default-tcp-server)
-        - [Run a TLS (HTTP/2) server only](#run-a-tls-http2-server-only)
+    - [Run a default TCP server with geo information enabled](#run-a-default-tco-server-with-geo-information-enabled)
+    - [Run a TLS (HTTP/2) and enable "what is my DNS" with geo information](#run-a-tls-http2-and-enable-what-is-my-dns-with-geo-information)
     - [Run an HTTP/3 server](#run-an-http3-server)
     - [Run a default TCP server with a custom template and trust a pair of custom headers set by an upstream proxy](#run-a-default-tcp-server-with-a-custom-template-and-trust-a-pair-of-custom-headers-set-by-an-upstream-proxy)
   - [Download](#download)
@@ -21,9 +23,14 @@
     - [Run a container locally using test databases](#run-a-container-locally-using-test-databases)
     - [From Docker Hub](#from-docker-hub)
 
-Just another "what is my IP address" service, including geolocation and headers information, written in go with high performance in mind, it uses [gin](https://github.com/gin-gonic/gin) which uses [httprouter](https://github.com/julienschmidt/httprouter) a lightweight high performance HTTP multiplexer.
+> [!NOTE]
+> Since version 3.0.0, geodb database is not mandatory, not adding the flags will disable the geo feature.
+> Since version 2.3.0, the application includes an optional client [DNS discovery](#dns-discovery)
 
-Take a look at [ifconfig.es](https://ifconfig.es) a live site using `whatismyip`
+Just another "what is my IP address" service, including geolocation, TCP open port checking, and headers information. Written in go with high performance in mind,
+it uses [gin](https://github.com/gin-gonic/gin) which uses [httprouter](https://github.com/julienschmidt/httprouter) a lightweight high performance HTTP multiplexer.
+
+Take a look at [ifconfig.es](https://ifconfig.es) a live site using `whatismyip` and the `DNS discovery` enabled.
 
 Get your public IP easily from the command line:
 
@@ -35,13 +42,22 @@ curl -6 ifconfig.es
 ::1
 ```
 
+Get the IP of your DNS provider:
+
+```bash
+curl -L dns.ifconfig.es
+2a04:e4c0:47::67 (Spain / OPENDNS)
+```
+
 ## Features
 
 - TLS and HTTP/2.
 - Experimental HTTP/3 support. HTTP/3 requires a TLS server running (`-tls-bind`), as HTTP/3 starts as a TLS connection that then gets upgraded to UDP. The UDP port is the same as the one used for the TLS server.
+- Beta DNS discovery: A best-effort approach to discovering the DNS server that is resolving the client's requests.
 - Can run behind a proxy by trusting a custom header (usually `X-Real-IP`) to figure out the source IP address. It also supports a custom header to resolve the client port, if the proxy can only add a header for the IP (for example a fixed header from CDNs) the client port is shown as unknown.
 - IPv4 and IPv6.
 - Geolocation info including ASN. This feature is possible thanks to [maxmind](https://dev.maxmind.com/geoip/geolite2-free-geolocation-data?lang=en) GeoLite2 databases. In order to use these databases, a license key is needed. Please visit Maxmind site for further instructions and get a free license.
+- Checking TCP open ports.
 - High performance.
 - Self-contained server that can reload GeoLite2 databases and/or SSL certificates without stop/start. The `hup` signal is honored.
 - HTML templates for the landing page.
@@ -66,10 +82,42 @@ curl -6 ifconfig.es
 - https://ifconfig.es/all
 - https://ifconfig.es/headers
   - https://ifconfig.es/<header_name>
+- https://ifconfig.es/scan/tcp/<port_number>
+- https://dns.ifconfig.es
+
+## DNS discovery
+
+The DNS discovery works by forcing the client to make a request to `<uuid>.dns.ifconfig.es` this DNS request is handled by a microdns server
+included in the `whatismyip` binary. In order to run the discovery server, a configuration file in the following form has to be created:
+
+```yaml
+---
+domain: dns.example.com
+redirect_port: ":8000"
+resource_records:
+  - "1800 IN SOA xns.example.com. hostmaster.example.com. 1 10000 2400 604800 1800"
+  - "3600 IN NS xns.example.com."
+ipv4:
+  - "127.0.0.2"
+ipv6:
+  - "aaa:aaa:aaa:aaaa::1"
+```
+
+The DNS authority for example.com has delegated the subdomain zone `dns.example.com` to the server running the `whatismyip` service.
+
+The client can request the URL `dns.example.com` by following the redirection `curl -L dns.example.com`.
+
+To avoid the redirection, you can provide a valid URL, for example, for the real [ifconfig.es](https://ifconfig.es):
+
+```bash
+curl $(uuidgen).dns.ifconfig.es
+
+curl $(cat /proc/sys/kernel/random/uuid).dns.ifconfig.es
+```
 
 ## Build
 
-Golang >= 1.19 is required.
+Golang >= 1.22 is required.
 
 `make build`
 
@@ -84,11 +132,13 @@ Usage of whatismyip:
   -enable-secure-headers
       Add sane security-related headers to every response
   -geoip2-asn string
-        Path to GeoIP2 ASN database
+      Path to GeoIP2 ASN database. Enables ASN information. (--geoip2-city becomes mandatory)
   -geoip2-city string
-        Path to GeoIP2 city database
+      Path to GeoIP2 city database. Enables geo information (--geoip2-asn becomes mandatory)
+  -resolver string
+      Path to the resolver configuration. It actually enables the resolver for DNS client discovery.
   -template string
-        Path to template file
+      Path to the template file
   -tls-bind string
       Listening address for TLS (see https://pkg.go.dev/net?#Listen)
   -tls-crt string
@@ -107,15 +157,22 @@ Usage of whatismyip:
 
 ### Run a default TCP server
 
+```bash
+./whatismyip
+```
+
+### Run a default TCP server with geo information enabled
+
 ```bash
 ./whatismyip -geoip2-city ./test/GeoIP2-City-Test.mmdb -geoip2-asn ./test/GeoLite2-ASN-Test.mmdb
 ```
 
-### Run a TLS (HTTP/2) server only
+### Run a TLS (HTTP/2) and enable "what is my DNS" with geo information
 
 ```bash
 ./whatismyip -geoip2-city ./test/GeoIP2-City-Test.mmdb -geoip2-asn ./test/GeoLite2-ASN-Test.mmdb \
-             -bind "" -tls-bind :8081 -tls-crt ./test/server.pem -tls-key ./test/server.key
+             -bind "" -tls-bind :8081 -tls-crt ./test/server.pem -tls-key ./test/server.key \
+             -resolver ./test/resolver.yml
 ```
 
 ### Run an HTTP/3 server
@@ -134,7 +191,7 @@ Usage of whatismyip:
 
 ## Download
 
-Download the latest version from https://github.com/dcarrillo/whatismyip/releases
+Download the latest version from [github](https://github.com/dcarrillo/whatismyip/releases)
 
 ## Docker
 

cmd/whatismyip.go

@@ -4,34 +4,57 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"net/http"
 	"os"
+	"slices"
+	"time"
 
 	"github.com/dcarrillo/whatismyip/internal/httputils"
 	"github.com/dcarrillo/whatismyip/internal/setting"
+	"github.com/dcarrillo/whatismyip/resolver"
 	"github.com/dcarrillo/whatismyip/server"
+	"github.com/dcarrillo/whatismyip/service"
 	"github.com/gin-contrib/secure"
+	"github.com/patrickmn/go-cache"
 
-	"github.com/dcarrillo/whatismyip/models"
 	"github.com/dcarrillo/whatismyip/router"
 	"github.com/gin-gonic/gin"
 )
 
 func main() {
 	o, err := setting.Setup(os.Args[1:])
+	if err != nil {
 		if err == flag.ErrHelp || err == setting.ErrVersion {
 			fmt.Print(o)
 			os.Exit(0)
-	} else if err != nil {
+		}
 		fmt.Println(err)
 		os.Exit(1)
 	}
 
-	models.Setup(setting.App.GeodbPath.City, setting.App.GeodbPath.ASN)
+	servers := []server.Server{}
 	engine := setupEngine()
-	router.SetupTemplate(engine)
-	router.Setup(engine)
 
-	whatismyip := server.Setup(context.Background(), engine.Handler())
+	if setting.App.Resolver.Domain != "" {
+		store := cache.New(1*time.Minute, 10*time.Minute)
+		dnsEngine := resolver.Setup(store)
+		nameServer := server.NewDNSServer(context.Background(), dnsEngine.Handler())
+		servers = append(servers, nameServer)
+		engine.Use(router.GetDNSDiscoveryHandler(store, setting.App.Resolver.Domain, setting.App.Resolver.RedirectPort))
+	}
+
+	var geoSvc *service.Geo
+	if setting.App.GeodbPath.City != "" || setting.App.GeodbPath.ASN != "" {
+		if geoSvc, err = service.NewGeo(context.Background(), setting.App.GeodbPath.City, setting.App.GeodbPath.ASN); err != nil {
+			panic(err)
+		}
+	}
+
+	router.SetupTemplate(engine)
+	router.Setup(engine, geoSvc)
+	servers = slices.Concat(servers, setupHTTPServers(context.Background(), engine.Handler()))
+
+	whatismyip := server.Setup(servers, geoSvc)
 	whatismyip.Run()
 }
 
@@ -41,8 +64,7 @@ func setupEngine() *gin.Engine {
 		gin.SetMode(gin.ReleaseMode)
 	}
 	engine := gin.New()
-	engine.Use(gin.LoggerWithFormatter(httputils.GetLogFormatter))
+	engine.Use(gin.LoggerWithFormatter(httputils.GetLogFormatter), gin.Recovery())
-	engine.Use(gin.Recovery())
 	if setting.App.EnableSecureHeaders {
 		engine.Use(secure.New(secure.Config{
 			BrowserXssFilter:   true,
@@ -55,3 +77,23 @@ func setupEngine() *gin.Engine {
 
 	return engine
 }
+
+func setupHTTPServers(ctx context.Context, handler http.Handler) []server.Server {
+	var servers []server.Server
+
+	if setting.App.BindAddress != "" {
+		tcpServer := server.NewTCPServer(ctx, &handler)
+		servers = append(servers, tcpServer)
+	}
+
+	if setting.App.TLSAddress != "" {
+		tlsServer := server.NewTLSServer(ctx, &handler)
+		servers = append(servers, tlsServer)
+		if setting.App.EnableHTTP3 {
+			quicServer := server.NewQuicServer(ctx, tlsServer)
+			servers = append(servers, quicServer)
+		}
+	}
+
+	return servers
+}

go.mod

@@ -1,79 +1,100 @@
 module github.com/dcarrillo/whatismyip
 
-go 1.21.3
+go 1.24
 
 require (
-	github.com/gin-contrib/secure v0.0.1
+	github.com/docker/docker v28.0.4+incompatible
-	github.com/gin-gonic/gin v1.9.1
+	github.com/gin-contrib/secure v1.1.2
-	github.com/oschwald/maxminddb-golang v1.12.0
+	github.com/gin-gonic/gin v1.10.0
-	github.com/quic-go/quic-go v0.39.0
+	github.com/google/uuid v1.6.0
-	github.com/stretchr/testify v1.8.4
+	github.com/miekg/dns v1.1.65
-	github.com/testcontainers/testcontainers-go v0.13.0
+	github.com/oschwald/maxminddb-golang v1.13.1
-	golang.org/x/net v0.17.0
+	github.com/patrickmn/go-cache v2.1.0+incompatible
+	github.com/quic-go/quic-go v0.50.1
+	github.com/stretchr/testify v1.10.0
+	github.com/testcontainers/testcontainers-go v0.36.0
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
+	dario.cat/mergo v1.0.1 // indirect
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
-	github.com/Microsoft/go-winio v0.5.2 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
-	github.com/Microsoft/hcsshim v0.9.6 // indirect
+	github.com/bytedance/sonic v1.13.2 // indirect
-	github.com/bytedance/sonic v1.10.2 // indirect
+	github.com/bytedance/sonic/loader v0.2.4 // indirect
-	github.com/cenkalti/backoff/v4 v4.1.3 // indirect
+	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
-	github.com/chenzhuoyu/base64x v0.0.0-20230717121745-296ad89f973d // indirect
+	github.com/cloudwego/base64x v0.1.5 // indirect
-	github.com/chenzhuoyu/iasm v0.9.0 // indirect
+	github.com/containerd/log v0.1.0 // indirect
-	github.com/containerd/cgroups v1.0.4 // indirect
+	github.com/containerd/platforms v0.2.1 // indirect
-	github.com/containerd/containerd v1.6.18 // indirect
+	github.com/cpuguy83/dockercfg v0.3.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/docker/distribution v2.8.2+incompatible // indirect
+	github.com/distribution/reference v0.6.0 // indirect
-	github.com/docker/docker v20.10.24+incompatible // indirect
+	github.com/docker/go-connections v0.5.0 // indirect
-	github.com/docker/go-connections v0.4.0 // indirect
+	github.com/docker/go-units v0.5.0 // indirect
-	github.com/docker/go-units v0.4.0 // indirect
+	github.com/ebitengine/purego v0.8.2 // indirect
-	github.com/gabriel-vasile/mimetype v1.4.2 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
-	github.com/gin-contrib/sse v0.1.0 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.8 // indirect
+	github.com/gin-contrib/sse v1.1.0 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/go-ole/go-ole v1.2.6 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
-	github.com/go-playground/validator/v10 v10.15.5 // indirect
+	github.com/go-playground/validator/v10 v10.26.0 // indirect
-	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
+	github.com/go-task/slim-sprig/v3 v3.0.0 // indirect
-	github.com/goccy/go-json v0.10.2 // indirect
+	github.com/goccy/go-json v0.10.5 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
-	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/google/pprof v0.0.0-20250403155104-27863c87afa6 // indirect
-	github.com/golang/mock v1.6.0 // indirect
-	github.com/golang/protobuf v1.5.3 // indirect
-	github.com/google/pprof v0.0.0-20230926050212-f7f687d19a98 // indirect
-	github.com/google/uuid v1.3.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/klauspost/cpuid/v2 v2.2.5 // indirect
+	github.com/klauspost/compress v1.17.4 // indirect
-	github.com/leodido/go-urn v1.2.4 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
-	github.com/magiconair/properties v1.8.6 // indirect
+	github.com/leodido/go-urn v1.4.0 // indirect
-	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
-	github.com/moby/sys/mount v0.3.3 // indirect
+	github.com/magiconair/properties v1.8.9 // indirect
-	github.com/moby/sys/mountinfo v0.6.2 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/moby/term v0.0.0-20220808134915-39b0c02b01ae // indirect
+	github.com/moby/docker-image-spec v1.3.1 // indirect
+	github.com/moby/patternmatcher v0.6.0 // indirect
+	github.com/moby/sys/sequential v0.5.0 // indirect
+	github.com/moby/sys/user v0.1.0 // indirect
+	github.com/moby/sys/userns v0.1.0 // indirect
+	github.com/moby/term v0.5.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/morikuni/aec v1.0.0 // indirect
-	github.com/onsi/ginkgo/v2 v2.13.0 // indirect
+	github.com/onsi/ginkgo/v2 v2.23.4 // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
-	github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799 // indirect
+	github.com/opencontainers/image-spec v1.1.1 // indirect
-	github.com/opencontainers/runc v1.1.5 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
-	github.com/pelletier/go-toml/v2 v2.1.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/quic-go/qpack v0.4.0 // indirect
+	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
-	github.com/quic-go/qtls-go1-20 v0.3.4 // indirect
+	github.com/quic-go/qpack v0.5.1 // indirect
-	github.com/sirupsen/logrus v1.9.0 // indirect
+	github.com/shirou/gopsutil/v4 v4.25.1 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/tklauser/go-sysconf v0.3.12 // indirect
+	github.com/tklauser/numcpus v0.6.1 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
-	github.com/ugorji/go/codec v1.2.11 // indirect
+	github.com/ugorji/go/codec v1.2.12 // indirect
-	go.opencensus.io v0.23.0 // indirect
+	github.com/yusufpapurcu/wmi v1.2.4 // indirect
-	go.uber.org/mock v0.3.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
-	golang.org/x/arch v0.5.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
-	golang.org/x/crypto v0.14.0 // indirect
+	go.opentelemetry.io/otel v1.35.0 // indirect
-	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.35.0 // indirect
-	golang.org/x/mod v0.13.0 // indirect
+	go.opentelemetry.io/otel/metric v1.35.0 // indirect
-	golang.org/x/sys v0.13.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.35.0 // indirect
-	golang.org/x/text v0.13.0 // indirect
+	go.opentelemetry.io/otel/trace v1.35.0 // indirect
-	golang.org/x/tools v0.14.0 // indirect
+	go.opentelemetry.io/proto/otlp v1.5.0 // indirect
-	google.golang.org/genproto v0.0.0-20230110181048-76db0878b65f // indirect
+	go.uber.org/automaxprocs v1.6.0 // indirect
-	google.golang.org/grpc v1.53.0 // indirect
+	go.uber.org/mock v0.5.1 // indirect
-	google.golang.org/protobuf v1.31.0 // indirect
+	golang.org/x/arch v0.16.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	golang.org/x/crypto v0.37.0 // indirect
+	golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 // indirect
+	golang.org/x/mod v0.24.0 // indirect
+	golang.org/x/net v0.39.0 // indirect
+	golang.org/x/sync v0.13.0 // indirect
+	golang.org/x/sys v0.32.0 // indirect
+	golang.org/x/text v0.24.0 // indirect
+	golang.org/x/tools v0.32.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20250414145226-207652e42e2e // indirect
+	google.golang.org/protobuf v1.36.6 // indirect
 )

integration-tests/integration_test.go

@@ -4,61 +4,77 @@ import (
 	"context"
 	"crypto/tls"
 	"encoding/json"
+	"fmt"
 	"io"
-	"log"
+	"net"
 	"net/http"
-	"path/filepath"
-	"runtime"
 	"strings"
 	"testing"
 
+	validator "github.com/dcarrillo/whatismyip/internal/validator/uuid"
 	"github.com/dcarrillo/whatismyip/router"
-	"github.com/quic-go/quic-go"
+	"github.com/docker/docker/api/types"
 	"github.com/quic-go/quic-go/http3"
 	"github.com/stretchr/testify/assert"
-	"github.com/testcontainers/testcontainers-go"
+	"github.com/stretchr/testify/require"
+	tc "github.com/testcontainers/testcontainers-go"
 	"github.com/testcontainers/testcontainers-go/wait"
 )
 
-func buildContainer() testcontainers.ContainerRequest {
+func customDialContext() func(ctx context.Context, network, addr string) (net.Conn, error) {
-	_, filename, _, _ := runtime.Caller(0)
+	return func(ctx context.Context, network, addr string) (net.Conn, error) {
-	dir := filepath.Dir(filename)
+		dialer := &net.Dialer{
-
+			Resolver: &net.Resolver{
-	req := testcontainers.ContainerRequest{
+				PreferGo: true,
-		FromDockerfile: testcontainers.FromDockerfile{
+				Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
-			Context:    "../",
+					d := net.Dialer{}
-			Dockerfile: "Dockerfile",
+					return d.DialContext(ctx, "udp", "127.0.0.1:53531")
 				},
-		Cmd: []string{
-			"-geoip2-city", "/tmp/GeoIP2-City-Test.mmdb",
-			"-geoip2-asn", "/tmp/GeoLite2-ASN-Test.mmdb",
-			"-bind", ":8000",
-			"-tls-bind", ":8001",
-			"-tls-crt", "/tmp/server.pem",
-			"-tls-key", "/tmp/server.key",
-			"-trusted-header", "X-Real-IP",
-			"-enable-secure-headers",
-			"-enable-http3",
 			},
-		ExposedPorts: []string{"8000:8000", "8001:8001", "8001:8001/udp"},
-		WaitingFor: wait.ForHTTP("/geo").
-			WithTLS(true, &tls.Config{InsecureSkipVerify: true}).
-			WithPort("8001"),
-		Mounts: testcontainers.Mounts(
-			testcontainers.BindMount(
-				filepath.Join(dir, "/../test/GeoIP2-City-Test.mmdb"),
-				"/tmp/GeoIP2-City-Test.mmdb",
-			),
-			testcontainers.BindMount(
-				filepath.Join(dir, "/../test/GeoLite2-ASN-Test.mmdb"),
-				"/tmp/GeoLite2-ASN-Test.mmdb",
-			),
-			testcontainers.BindMount(filepath.Join(dir, "/../test/server.pem"), "/tmp/server.pem"),
-			testcontainers.BindMount(filepath.Join(dir, "/../test/server.key"), "/tmp/server.key"),
-		),
 		}
 
-	return req
+		return dialer.DialContext(ctx, network, addr)
+	}
+}
+
+func testWhatIsMyDNS(t *testing.T) {
+	t.Run("RequestDNSDiscovery", func(t *testing.T) {
+		http.DefaultTransport.(*http.Transport).DialContext = customDialContext()
+		req, err := http.NewRequest("GET", "http://localhost:8000", nil)
+		assert.NoError(t, err)
+		req.Host = "dns.example.com"
+		client := &http.Client{
+			CheckRedirect: func(_ *http.Request, _ []*http.Request) error {
+				return http.ErrUseLastResponse
+			},
+		}
+
+		resp, err := client.Do(req)
+		assert.NoError(t, err)
+		assert.Equal(t, http.StatusFound, resp.StatusCode)
+		u, err := resp.Location()
+		assert.NoError(t, err)
+		assert.True(t, validator.IsValid(strings.Split(u.Hostname(), ".")[0]))
+
+		for _, accept := range []string{"application/json", "*/*", "text/html"} {
+			req, err = http.NewRequest("GET", u.String(), nil)
+			req.Host = u.Hostname()
+			req.Header.Set("Accept", accept)
+			assert.NoError(t, err)
+			resp, err = client.Do(req)
+			assert.NoError(t, err)
+			assert.Equal(t, http.StatusOK, resp.StatusCode)
+			body, err := io.ReadAll(resp.Body)
+			assert.NoError(t, err)
+
+			if accept == "application/json" {
+				assert.NoError(t, json.Unmarshal(body, &router.DNSJSONResponse{}))
+			} else {
+				ip := strings.Split(string(body), " ")[0]
+				assert.True(t, net.ParseIP(ip) != nil)
+			}
+		}
+	})
 }
 
 func TestContainerIntegration(t *testing.T) {
@@ -67,22 +83,66 @@ func TestContainerIntegration(t *testing.T) {
 	}
 
 	ctx := context.Background()
-	container, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
+	c, err := tc.GenericContainer(ctx, tc.GenericContainerRequest{
-		ContainerRequest: buildContainer(),
+		ContainerRequest: tc.ContainerRequest{
+			FromDockerfile: tc.FromDockerfile{
+				Context:       "../",
+				Dockerfile:    "./test/Dockerfile",
+				PrintBuildLog: true,
+				KeepImage:     false,
+				BuildOptionsModifier: func(buildOptions *types.ImageBuildOptions) {
+					buildOptions.Target = "test"
+				},
+			},
+			ExposedPorts: []string{
+				"8000:8000",
+				"8001:8001",
+				"8001:8001/udp",
+				"53531:53/udp",
+			},
+			Cmd: []string{
+				"-geoip2-city", "/GeoIP2-City-Test.mmdb",
+				"-geoip2-asn", "/GeoLite2-ASN-Test.mmdb",
+				"-bind", ":8000",
+				"-tls-bind", ":8001",
+				"-tls-crt", "/server.pem",
+				"-tls-key", "/server.key",
+				"-trusted-header", "X-Real-IP",
+				"-enable-secure-headers",
+				"-enable-http3",
+				"-resolver", "/resolver.yml",
+			},
+			Files: []tc.ContainerFile{
+				{
+					HostFilePath:      "./../test/GeoIP2-City-Test.mmdb",
+					ContainerFilePath: "/GeoIP2-City-Test.mmdb",
+				},
+				{
+					HostFilePath:      "./../test/GeoLite2-ASN-Test.mmdb",
+					ContainerFilePath: "/GeoLite2-ASN-Test.mmdb",
+				},
+				{
+					HostFilePath:      "./../test/server.pem",
+					ContainerFilePath: "/server.pem",
+				},
+				{
+					HostFilePath:      "./../test/server.key",
+					ContainerFilePath: "/server.key",
+				},
+				{
+					HostFilePath:      "./../test/resolver.yml",
+					ContainerFilePath: "/resolver.yml",
+				},
+			},
+			WaitingFor: wait.ForLog("Starting QUIC server"),
+			AutoRemove: true,
+		},
 		Started: true,
 	})
-	if err != nil {
+	require.NoError(t, err)
-		log.Fatal(err)
+	t.Cleanup(func() { c.Terminate(ctx) })
-	}
-	defer func() {
-		err = container.Terminate(ctx)
-		if err != nil {
-			log.Fatal(err)
-		}
-	}()
 
 	http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
-
 	tests := []struct {
 		name string
 		url  string
@@ -105,9 +165,27 @@ func TestContainerIntegration(t *testing.T) {
 		},
 	}
 
+	testsPortScan := []struct {
+		name string
+		port int
+		want bool
+	}{
+		{
+			name: "RequestOpenPortScan",
+			port: 8000,
+			want: true,
+		},
+		{
+			name: "RequestClosedPortScan",
+			port: 65533,
+			want: false,
+		},
+	}
+
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			req, _ := http.NewRequest("GET", tt.url, nil)
+			req, err := http.NewRequest("GET", tt.url, nil)
+			assert.NoError(t, err)
 			req.Header.Set("Accept", "application/json")
 
 			var resp *http.Response
@@ -116,8 +194,10 @@ func TestContainerIntegration(t *testing.T) {
 				resp, body, err = doQuicRequest(req)
 			} else {
 				client := &http.Client{}
-				resp, _ = client.Do(req)
+				resp, err = client.Do(req)
+				assert.NoError(t, err)
 				body, err = io.ReadAll(resp.Body)
+				assert.NoError(t, err)
 				if strings.Contains(tt.url, "https://") {
 					assert.Equal(t, `h3=":8001"; ma=2592000`, resp.Header.Get("Alt-Svc"))
 				}
@@ -131,14 +211,35 @@ func TestContainerIntegration(t *testing.T) {
 			assert.Equal(t, "1; mode=block", resp.Header.Get("X-Xss-Protection"))
 		})
 	}
+
+	for _, tt := range testsPortScan {
+		t.Run(tt.name, func(t *testing.T) {
+			req, err := http.NewRequest("GET", fmt.Sprintf("http://localhost:8000/scan/tcp/%d", tt.port), nil)
+			assert.NoError(t, err)
+			req.Header.Set("Accept", "application/json")
+			req.Header.Set("X-Real-IP", "127.0.0.1")
+
+			client := &http.Client{}
+			resp, err := client.Do(req)
+			assert.NoError(t, err)
+			assert.Equal(t, 200, resp.StatusCode)
+
+			body, err := io.ReadAll(resp.Body)
+			assert.NoError(t, err)
+			j := router.JSONScanResponse{}
+			assert.NoError(t, json.Unmarshal(body, &j))
+			assert.Equal(t, tt.want, j.Reachable)
+		})
+	}
+
+	testWhatIsMyDNS(t)
 }
 
 func doQuicRequest(req *http.Request) (*http.Response, []byte, error) {
-	roundTripper := &http3.RoundTripper{
+	roundTripper := &http3.Transport{
 		TLSClientConfig: &tls.Config{
 			InsecureSkipVerify: true,
 		},
-		QuicConfig: &quic.Config{},
 	}
 	defer roundTripper.Close()
 

internal/httputils/http.go

@@ -63,7 +63,7 @@ func GetLogFormatter(param gin.LogFormatterParams) string {
 	)
 }
 
-func normalizeLog(log interface{}) interface{} {
+func normalizeLog(log any) any {
 	switch v := log.(type) {
 	case string:
 		if v == "" {

internal/setting/app.go

@@ -9,18 +9,29 @@ import (
 	"time"
 
 	"github.com/dcarrillo/whatismyip/internal/core"
+	"gopkg.in/yaml.v3"
 )
 
-type geodbPath struct {
+type geodbConf struct {
 	City  string
 	ASN   string
+	Token *string
 }
 type serverSettings struct {
 	ReadTimeout  time.Duration
 	WriteTimeout time.Duration
 }
+
+type resolver struct {
+	Domain          string   `yaml:"domain"`
+	ResourceRecords []string `yaml:"resource_records"`
+	RedirectPort    string   `yaml:"redirect_port,omitempty"`
+	Ipv4            []string `yaml:"ipv4,omitempty"`
+	Ipv6            []string `yaml:"ipv6,omitempty"`
+}
+
 type settings struct {
-	GeodbPath           geodbPath
+	GeodbPath           geodbConf
 	TemplatePath        string
 	BindAddress         string
 	TLSAddress          string
@@ -31,15 +42,14 @@ type settings struct {
 	EnableSecureHeaders bool
 	EnableHTTP3         bool
 	Server              serverSettings
+	Resolver            resolver
 	version             bool
 }
 
 const defaultAddress = ":8080"
 
-// ErrVersion is the custom error triggered when -version flag is passed
 var ErrVersion = errors.New("setting: version requested")
 
-// App is the var with the parsed settings
 var App = settings{
 	// hard-coded for the time being
 	Server: serverSettings{
@@ -48,15 +58,20 @@ var App = settings{
 	},
 }
 
-// Setup initializes the App object parsing the flags
 func Setup(args []string) (output string, err error) {
 	flags := flag.NewFlagSet("whatismyip", flag.ContinueOnError)
 	var buf bytes.Buffer
+	var resolverConf string
 	flags.SetOutput(&buf)
 
-	flags.StringVar(&App.GeodbPath.City, "geoip2-city", "", "Path to GeoIP2 city database")
+	flags.StringVar(&App.GeodbPath.City, "geoip2-city", "", "Path to GeoIP2 city database. Enables geo information (--geoip2-asn becomes mandatory)")
-	flags.StringVar(&App.GeodbPath.ASN, "geoip2-asn", "", "Path to GeoIP2 ASN database")
+	flags.StringVar(&App.GeodbPath.ASN, "geoip2-asn", "", "Path to GeoIP2 ASN database. Enables ASN information. (--geoip2-city becomes mandatory)")
-	flags.StringVar(&App.TemplatePath, "template", "", "Path to template file")
+	flags.StringVar(&App.TemplatePath, "template", "", "Path to the template file")
+	flags.StringVar(
+		&resolverConf,
+		"resolver",
+		"",
+		"Path to the resolver configuration. It actually enables the resolver for DNS client discovery.")
 	flags.StringVar(
 		&App.BindAddress,
 		"bind",
@@ -106,12 +121,12 @@ func Setup(args []string) (output string, err error) {
 		return fmt.Sprintf("whatismyip version %s", core.Version), ErrVersion
 	}
 
-	if App.TrustedPortHeader != "" && App.TrustedHeader == "" {
+	if (App.GeodbPath.City != "" && App.GeodbPath.ASN == "") || (App.GeodbPath.City == "" && App.GeodbPath.ASN != "") {
-		return "", fmt.Errorf("truster-header is mandatory when truster-port-header is set")
+		return "", fmt.Errorf("both --geoip2-city and --geoip2-asn are mandatory to enable geo information")
 	}
 
-	if App.GeodbPath.City == "" || App.GeodbPath.ASN == "" {
+	if App.TrustedPortHeader != "" && App.TrustedHeader == "" {
-		return "", fmt.Errorf("geoip2-city and geoip2-asn parameters are mandatory")
+		return "", fmt.Errorf("truster-header is mandatory when truster-port-header is set")
 	}
 
 	if (App.TLSAddress != "") && (App.TLSCrtPath == "" || App.TLSKeyPath == "") {
@@ -132,5 +147,21 @@ func Setup(args []string) (output string, err error) {
 		}
 	}
 
+	if resolverConf != "" {
+		var err error
+		App.Resolver, err = readYAML(resolverConf)
+		if err != nil {
+			return "", fmt.Errorf("error reading resolver configuration %w", err)
+		}
+	}
+
 	return buf.String(), nil
 }
+
+func readYAML(path string) (resolver resolver, err error) {
+	yamlFile, err := os.ReadFile(path)
+	if err != nil {
+		return resolver, err
+	}
+	return resolver, yaml.Unmarshal(yamlFile, &resolver)
+}

internal/setting/app_test.go

@@ -12,44 +12,43 @@ import (
 )
 
 func TestParseMandatoryFlags(t *testing.T) {
-	var mandatoryFlags = []struct {
+	mandatoryFlags := []struct {
 		args []string
 	}{
-		{
-			[]string{},
-		},
-		{
-			[]string{"-geoip2-city", "/city-path"},
-		},
-		{
-			[]string{"-geoip2-asn", "/asn-path"},
-		},
 		{
 			[]string{
-				"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path", "-tls-bind", ":9000",
+				"-geoip2-city", "my-city-path",
 			},
 		},
 		{
 			[]string{
-				"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path", "-tls-bind", ":9000",
+				"-geoip2-asn", "my-asn-path",
-				"-tls-crt", "/crt-path",
+			},
+		},
+
+		{
+			[]string{
+				"-tls-bind", ":9000",
 			},
 		},
 		{
 			[]string{
-				"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path", "-tls-bind", ":9000",
+				"-tls-bind", ":9000", "-tls-crt", "/crt-path",
-				"-tls-key", "/key-path",
 			},
 		},
 		{
 			[]string{
-				"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path", "-enable-http3",
+				"-tls-bind", ":9000", "-tls-key", "/key-path",
 			},
 		},
 		{
 			[]string{
-				"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path", "-bind", ":8000",
+				"-enable-http3",
-				"-trusted-port-header", "port-header",
+			},
+		},
+		{
+			[]string{
+				"-bind", ":8000", "-trusted-port-header", "port-header",
 			},
 		},
 	}
@@ -57,24 +56,20 @@ func TestParseMandatoryFlags(t *testing.T) {
 	for _, tt := range mandatoryFlags {
 		t.Run(strings.Join(tt.args, " "), func(t *testing.T) {
 			_, err := Setup(tt.args)
-			require.NotNil(t, err)
+			require.Error(t, err)
 			assert.Contains(t, err.Error(), "mandatory")
 		})
 	}
 }
 
 func TestParseFlags(t *testing.T) {
-	var flags = []struct {
+	flags := []struct {
 		args []string
 		conf settings
 	}{
 		{
-			[]string{"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path"},
+			[]string{},
 			settings{
-				GeodbPath: geodbPath{
-					City: "/city-path",
-					ASN:  "/asn-path",
-				},
 				BindAddress: ":8080",
 				Server: serverSettings{
 					ReadTimeout:  10 * time.Second,
@@ -85,7 +80,7 @@ func TestParseFlags(t *testing.T) {
 		{
 			[]string{"-bind", ":8001", "-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path"},
 			settings{
-				GeodbPath: geodbPath{
+				GeodbPath: geodbConf{
 					City: "/city-path",
 					ASN:  "/asn-path",
 				},
@@ -102,7 +97,7 @@ func TestParseFlags(t *testing.T) {
 				"-tls-crt", "/crt-path", "-tls-key", "/key-path",
 			},
 			settings{
-				GeodbPath: geodbPath{
+				GeodbPath: geodbConf{
 					City: "/city-path",
 					ASN:  "/asn-path",
 				},
@@ -122,7 +117,7 @@ func TestParseFlags(t *testing.T) {
 				"-trusted-header", "header", "-trusted-port-header", "port-header",
 			},
 			settings{
-				GeodbPath: geodbPath{
+				GeodbPath: geodbConf{
 					City: "/city-path",
 					ASN:  "/asn-path",
 				},
@@ -141,7 +136,7 @@ func TestParseFlags(t *testing.T) {
 				"-trusted-header", "header", "-enable-secure-headers",
 			},
 			settings{
-				GeodbPath: geodbPath{
+				GeodbPath: geodbConf{
 					City: "/city-path",
 					ASN:  "/asn-path",
 				},
@@ -166,7 +161,7 @@ func TestParseFlags(t *testing.T) {
 }
 
 func TestParseFlagsUsage(t *testing.T) {
-	var usageArgs = []string{"-help", "-h", "--help"}
+	usageArgs := []string{"-help", "-h", "--help"}
 
 	for _, arg := range usageArgs {
 		t.Run(arg, func(t *testing.T) {
@@ -184,19 +179,28 @@ func TestParseFlagVersion(t *testing.T) {
 }
 
 func TestParseFlagTemplate(t *testing.T) {
-	flags := []string{
+	testCases := []struct {
-		"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path",
+		name   string
-		"-template", "/template-path",
+		flags  []string
+		errMsg string
+	}{
+		{
+			name:   "Invalid template path",
+			flags:  []string{"-template", "/template-path"},
+			errMsg: "no such file or directory",
+		},
+		{
+			name:   "Template path is a directory",
+			flags:  []string{"-template", "/"},
+			errMsg: "must be a file",
+		},
 	}
-	_, err := Setup(flags)
-	assert.Error(t, err)
-	assert.Contains(t, err.Error(), "no such file or directory")
 
-	flags = []string{
+	for _, tc := range testCases {
-		"-geoip2-city", "/city-path", "-geoip2-asn", "/asn-path",
+		t.Run(tc.name, func(t *testing.T) {
-		"-template", "/",
+			_, err := Setup(tc.flags)
-	}
-	_, err = Setup(flags)
 			require.Error(t, err)
-	assert.Contains(t, err.Error(), "must be a file")
+			assert.Contains(t, err.Error(), tc.errMsg)
+		})
+	}
 }

internal/validator/uuid/uuid.go

@@ -0,0 +1,10 @@
+package uuid
+
+import (
+	"github.com/google/uuid"
+)
+
+func IsValid(u string) bool {
+	_, err := uuid.Parse(u)
+	return err == nil
+}

internal/validator/uuid/uuid_test.go

@@ -0,0 +1,37 @@
+package uuid
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsValid(t *testing.T) {
+	tests := []struct {
+		name string
+		u    string
+		want bool
+	}{
+		{
+			name: "Valid UUID",
+			u:    "3b241101-e2bb-4255-8caf-4136c566a964",
+			want: true,
+		},
+		{
+			name: "Invalid UUID",
+			u:    "invalid-uuid",
+			want: false,
+		},
+		{
+			name: "Empty string",
+			u:    "",
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.True(t, IsValid(tt.u) == tt.want)
+		})
+	}
+}

models/geo.go

@@ -1,13 +1,13 @@
 package models
 
 import (
+	"fmt"
 	"log"
 	"net"
 
 	"github.com/oschwald/maxminddb-golang"
 )
 
-// GeoRecord is the model for City database
 type GeoRecord struct {
 	Country struct {
 		ISOCode string            `maxminddb:"iso_code"`
@@ -26,52 +26,107 @@ type GeoRecord struct {
 	} `maxminddb:"postal"`
 }
 
-// ASNRecord is the model for ASN database
 type ASNRecord struct {
 	AutonomousSystemNumber       uint   `maxminddb:"autonomous_system_number"`
 	AutonomousSystemOrganization string `maxminddb:"autonomous_system_organization"`
 }
 
-type geodb struct {
+type GeoDB struct {
-	city *maxminddb.Reader
+	cityPath string
-	asn  *maxminddb.Reader
+	asnPath  string
+	City     *maxminddb.Reader
+	ASN      *maxminddb.Reader
 }
 
-var db geodb
+func Setup(cityPath string, asnPath string) (*GeoDB, error) {
+	city, asn, err := openDatabases(cityPath, asnPath)
+	if err != nil {
+		return nil, err
+	}
 
-func openMMDB(path string) *maxminddb.Reader {
+	return &GeoDB{
+		cityPath: cityPath,
+		asnPath:  asnPath,
+		City:     city,
+		ASN:      asn,
+	}, nil
+}
+
+func (db *GeoDB) CloseDBs() error {
+	var errs []error
+
+	if db.City != nil {
+		if err := db.City.Close(); err != nil {
+			errs = append(errs, fmt.Errorf("closing city db: %w", err))
+		}
+	}
+
+	if db.ASN != nil {
+		if err := db.ASN.Close(); err != nil {
+			errs = append(errs, fmt.Errorf("closing ASN db: %w", err))
+		}
+	}
+
+	if len(errs) > 0 {
+		return fmt.Errorf("errors closing databases: %s", errs)
+	}
+	return nil
+}
+
+func (db *GeoDB) Reload() error {
+	if err := db.CloseDBs(); err != nil {
+		return fmt.Errorf("closing existing connections: %w", err)
+	}
+
+	city, asn, err := openDatabases(db.cityPath, db.asnPath)
+	if err != nil {
+		return fmt.Errorf("opening new connections: %w", err)
+	}
+
+	db.City = city
+	db.ASN = asn
+	return nil
+}
+
+func (db *GeoDB) LookupCity(ip net.IP) (*GeoRecord, error) {
+	record := &GeoRecord{}
+	err := db.City.Lookup(ip, record)
+	if err != nil {
+		return nil, err
+	}
+
+	return record, nil
+}
+
+func (db *GeoDB) LookupASN(ip net.IP) (*ASNRecord, error) {
+	record := &ASNRecord{}
+	err := db.ASN.Lookup(ip, record)
+	if err != nil {
+		return nil, err
+	}
+	return record, nil
+}
+
+func openDatabases(cityPath, asnPath string) (*maxminddb.Reader, *maxminddb.Reader, error) {
+	city, err := openMMDB(cityPath)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	asn, err := openMMDB(asnPath)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return city, asn, nil
+}
+
+func openMMDB(path string) (*maxminddb.Reader, error) {
 	db, err := maxminddb.Open(path)
 	if err != nil {
-		log.Fatal(err)
+		return nil, err
 	}
 	log.Printf("Database %s has been loaded\n", path)
 
-	return db
+	return db, nil
-}
-
-// Setup opens all Geolite2 databases
-func Setup(cityPath string, asnPath string) {
-	db.city = openMMDB(cityPath)
-	db.asn = openMMDB(asnPath)
-}
-
-// CloseDBs unmaps from memory and frees resources to the filesystem
-func CloseDBs() {
-	log.Printf("Closing dbs...")
-	if err := db.city.Close(); err != nil {
-		log.Printf("Error closing city db: %s", err)
-	}
-	if err := db.asn.Close(); err != nil {
-		log.Printf("Error closing ASN db: %s", err)
-	}
-}
-
-// LookUp an IP and get city data
-func (record *GeoRecord) LookUp(ip net.IP) error {
-	return db.city.Lookup(ip, record)
-}
-
-// LookUp an IP and get ASN data
-func (record *ASNRecord) LookUp(ip net.IP) error {
-	return db.asn.Lookup(ip, record)
 }

models/geo_test.go

@@ -1,10 +1,12 @@
 package models
 
 import (
+	"fmt"
 	"net"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestModels(t *testing.T) {
@@ -59,19 +61,21 @@ func TestModels(t *testing.T) {
 		AutonomousSystemOrganization: "IP-Only",
 	}
 
-	Setup("../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
+	db, err := Setup("../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
-	defer CloseDBs()
+	require.NoError(t, err, fmt.Sprintf("Error setting up db: %s", err))
+	defer db.CloseDBs()
+	assert.NotNil(t, db.ASN)
+	assert.NotNil(t, db.City)
 
-	assert.NotNil(t, db.asn)
+	cityRecord, err := db.LookupCity(net.ParseIP("81.2.69.192"))
-	assert.NotNil(t, db.city)
+	require.NoError(t, err, fmt.Sprintf("Error looking up city: %s", err))
-
-	cityRecord := &GeoRecord{}
-	assert.Nil(t, cityRecord.LookUp(net.ParseIP("81.2.69.192")))
 	assert.Equal(t, expectedCity, cityRecord)
-	assert.Error(t, cityRecord.LookUp(net.ParseIP("error")))
+	_, err = db.LookupCity(net.ParseIP("error"))
+	assert.Error(t, err)
 
-	asnRecord := &ASNRecord{}
+	asnRecord, err := db.LookupASN(net.ParseIP("82.99.17.64"))
-	assert.Nil(t, asnRecord.LookUp(net.ParseIP("82.99.17.64")))
+	require.NoError(t, err, fmt.Sprintf("Error looking up asn: %s", err))
 	assert.Equal(t, expectedASN, asnRecord)
-	assert.Error(t, asnRecord.LookUp(net.ParseIP("error")))
+	_, err = db.LookupASN(net.ParseIP("error"))
+	assert.Error(t, err)
 }

resolver/setup.go

@@ -0,0 +1,165 @@
+package resolver
+
+import (
+	"log"
+	"net"
+	"strings"
+
+	"github.com/dcarrillo/whatismyip/internal/setting"
+	"github.com/dcarrillo/whatismyip/internal/validator/uuid"
+	"github.com/miekg/dns"
+	"github.com/patrickmn/go-cache"
+)
+
+type Resolver struct {
+	handler *dns.ServeMux
+	store   *cache.Cache
+	domain  string
+	rr      []string
+	ipv4    []net.IP
+	ipv6    []net.IP
+}
+
+func ensureDotSuffix(s string) string {
+	if !strings.HasSuffix(s, ".") {
+		return s + "."
+	}
+	return s
+}
+
+func Setup(store *cache.Cache) *Resolver {
+	var ipv4, ipv6 []net.IP
+	for _, ip := range setting.App.Resolver.Ipv4 {
+		ipv4 = append(ipv4, net.ParseIP(ip))
+	}
+	for _, ip := range setting.App.Resolver.Ipv6 {
+		ipv6 = append(ipv6, net.ParseIP(ip))
+	}
+
+	resolver := &Resolver{
+		handler: dns.NewServeMux(),
+		store:   store,
+		domain:  ensureDotSuffix(setting.App.Resolver.Domain),
+		rr:      setting.App.Resolver.ResourceRecords,
+		ipv4:    ipv4,
+		ipv6:    ipv6,
+	}
+	resolver.handler.HandleFunc(resolver.domain, resolver.resolve)
+	resolver.handler.HandleFunc(".", resolver.blackHole)
+
+	return resolver
+}
+
+func (rsv *Resolver) Handler() *dns.ServeMux {
+	return rsv.handler
+}
+
+func (rsv *Resolver) blackHole(w dns.ResponseWriter, r *dns.Msg) {
+	msg := startReply(r)
+	msg.SetRcode(r, dns.RcodeRefused)
+	w.WriteMsg(msg)
+	logger(w, r.Question[0], msg.Rcode)
+}
+
+func (rsv *Resolver) resolve(w dns.ResponseWriter, r *dns.Msg) {
+	msg := startReply(r)
+	q := r.Question[0]
+	ip, _, _ := net.SplitHostPort(w.RemoteAddr().String())
+
+	for _, res := range rsv.rr {
+		t := strings.Split(res, " ")[2]
+		if q.Qtype == dns.StringToType[t] {
+			brr, err := buildRR(rsv.domain + " " + res)
+			if err != nil {
+				msg.SetRcode(r, dns.RcodeServerFailure)
+				logger(w, q, msg.Rcode, err.Error())
+			} else {
+				msg.Answer = append(msg.Answer, brr)
+				logger(w, q, msg.Rcode)
+			}
+			w.WriteMsg(msg)
+			return
+		}
+	}
+
+	lowerName := strings.ToLower(q.Name) // lowercase because of dns-0x20
+	subDomain := strings.Split(lowerName, ".")[0]
+	switch {
+	case uuid.IsValid(subDomain):
+		msg.SetRcode(r, rsv.getIP(q, msg))
+		rsv.store.Add(subDomain, ip, cache.DefaultExpiration)
+	case lowerName == rsv.domain:
+		msg.SetRcode(r, rsv.getIP(q, msg))
+	default:
+		msg.SetRcode(r, dns.RcodeRefused)
+	}
+
+	w.WriteMsg(msg)
+	logger(w, q, msg.Rcode)
+}
+
+func (rsv *Resolver) getIP(question dns.Question, msg *dns.Msg) int {
+	if question.Qtype == dns.TypeA && len(rsv.ipv4) > 0 {
+		for _, ip := range rsv.ipv4 {
+			msg.Answer = append(msg.Answer, &dns.A{
+				Hdr: setHdr(question),
+				A:   ip,
+			})
+		}
+		return dns.RcodeSuccess
+	}
+
+	if question.Qtype == dns.TypeAAAA && len(rsv.ipv6) > 0 {
+		for _, ip := range rsv.ipv6 {
+			msg.Answer = append(msg.Answer, &dns.AAAA{
+				Hdr:  setHdr(question),
+				AAAA: ip,
+			})
+		}
+		return dns.RcodeSuccess
+	}
+
+	return dns.RcodeRefused
+}
+
+func buildRR(rrs string) (dns.RR, error) {
+	rr, err := dns.NewRR(rrs)
+	if err != nil {
+		return nil, err
+	}
+
+	return rr, nil
+}
+
+func setHdr(q dns.Question) dns.RR_Header {
+	return dns.RR_Header{
+		Name:   q.Name,
+		Rrtype: q.Qtype,
+		Class:  dns.ClassINET,
+		Ttl:    60,
+	}
+}
+
+func startReply(r *dns.Msg) *dns.Msg {
+	msg := new(dns.Msg)
+	msg.SetReply(r)
+	msg.Authoritative = true
+
+	return msg
+}
+
+func logger(w dns.ResponseWriter, q dns.Question, code int, err ...string) {
+	emsg := ""
+	if len(err) > 0 {
+		emsg = " - " + strings.Join(err, " ")
+	}
+	ip, _, _ := net.SplitHostPort(w.RemoteAddr().String())
+	log.Printf(
+		"DNS %s - %s - %s - %s%s",
+		ip,
+		dns.TypeToString[q.Qtype],
+		q.Name,
+		dns.RcodeToString[code],
+		emsg,
+	)
+}

router/dns.go

@@ -0,0 +1,97 @@
+package router
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+
+	validator "github.com/dcarrillo/whatismyip/internal/validator/uuid"
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/patrickmn/go-cache"
+)
+
+type DNSJSONResponse struct {
+	DNS dnsData `json:"dns"`
+}
+type dnsGeoData struct {
+	Country         string `json:"country,omitempty"`
+	AsnOrganization string `json:"provider,omitempty"`
+}
+
+type dnsData struct {
+	IP string `json:"ip"`
+	dnsGeoData
+}
+
+// TODO
+// Implement a proper vhost manager instead of using a middleware
+func GetDNSDiscoveryHandler(store *cache.Cache, domain string, redirectPort string) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		if !strings.HasSuffix(ctx.Request.Host, domain) {
+			ctx.Next()
+			return
+		}
+
+		if ctx.Request.Host == domain && ctx.Request.URL.Path == "/" {
+			ctx.Redirect(http.StatusFound, fmt.Sprintf("http://%s.%s%s", uuid.New().String(), domain, redirectPort))
+			ctx.Abort()
+			return
+		}
+
+		handleDNS(ctx, store)
+		ctx.Abort()
+	}
+}
+
+func handleDNS(ctx *gin.Context, store *cache.Cache) {
+	d := strings.Split(ctx.Request.Host, ".")[0]
+	if !validator.IsValid(d) {
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
+		return
+	}
+
+	v, found := store.Get(d)
+	if !found {
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
+		return
+	}
+
+	ipStr, ok := v.(string)
+	if !ok {
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
+		return
+	}
+
+	ip := net.ParseIP(ipStr)
+	if ip == nil {
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
+		return
+	}
+
+	geoResp := dnsGeoData{}
+	if geoSvc != nil {
+		cityRecord := geoSvc.LookUpCity(ip)
+		asnRecord := geoSvc.LookUpASN(ip)
+
+		geoResp = dnsGeoData{
+			Country:         cityRecord.Country.Names["en"],
+			AsnOrganization: asnRecord.AutonomousSystemOrganization,
+		}
+	}
+
+	j := DNSJSONResponse{
+		DNS: dnsData{
+			IP:         ipStr,
+			dnsGeoData: geoResp,
+		},
+	}
+
+	switch ctx.NegotiateFormat(gin.MIMEPlain, gin.MIMEHTML, gin.MIMEJSON) {
+	case gin.MIMEJSON:
+		ctx.JSON(http.StatusOK, j)
+	default:
+		ctx.String(http.StatusOK, fmt.Sprintf("%s (%s / %s)\n", j.DNS.IP, j.DNS.Country, j.DNS.AsnOrganization))
+	}
+}

router/dns_test.go

@@ -0,0 +1,153 @@
+package router
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+
+	validator "github.com/dcarrillo/whatismyip/internal/validator/uuid"
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/patrickmn/go-cache"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetDNSDiscoveryHandler(t *testing.T) {
+	store := cache.New(cache.NoExpiration, cache.NoExpiration)
+	handler := GetDNSDiscoveryHandler(store, domain, "")
+
+	t.Run("calls next if host does not have domain suffix", func(t *testing.T) {
+		req, _ := http.NewRequest("GET", "/", nil)
+		req.Header.Set(trustedHeader, testIP.ipv4)
+		req.Host = "example.com"
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = req
+		handler(c)
+		app.ServeHTTP(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Equal(t, testIP.ipv4+"\n", w.Body.String())
+	})
+
+	t.Run("return 404 if there is a path", func(t *testing.T) {
+		req, _ := http.NewRequest("GET", "/path", nil)
+		req.Host = domain
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = req
+		handler(c)
+		app.ServeHTTP(w, req)
+
+		assert.Equal(t, http.StatusNotFound, w.Code)
+	})
+
+	t.Run("redirects if host is domain", func(t *testing.T) {
+		req, _ := http.NewRequest("GET", "/", nil)
+		req.Host = domain
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = req
+		handler(c)
+
+		assert.Equal(t, http.StatusFound, w.Code)
+		r, err := url.Parse(w.Header().Get("Location"))
+		assert.NoError(t, err)
+		assert.True(t, validator.IsValid(strings.Split(r.Host, ".")[0]))
+		assert.Equal(t, domain, strings.Join(strings.Split(r.Host, ".")[1:], "."))
+	})
+}
+
+func TestHandleDNS(t *testing.T) {
+	store := cache.New(cache.NoExpiration, cache.NoExpiration)
+	u := uuid.New().String()
+
+	tests := []struct {
+		name      string
+		subDomain string
+		stored    any
+	}{
+		{
+			name:      "not found if the subdomain is not a valid uuid",
+			subDomain: "not-uuid",
+			stored:    "",
+		},
+		{
+			name:      "not found if the ip is not found in the store",
+			subDomain: u,
+			stored:    "",
+		},
+		{
+			name:      "not found if the ip is in store but is not valid",
+			subDomain: u,
+			stored:    "bogus",
+		},
+		{
+			name:      "not found if the store contains no string",
+			subDomain: u,
+			stored:    20,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req, _ := http.NewRequest("GET", "/", nil)
+			req.Host = tt.subDomain + "." + domain
+
+			if tt.stored != "" {
+				store.Add(tt.subDomain, tt.stored, cache.DefaultExpiration)
+			}
+
+			w := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(w)
+			c.Request = req
+			handleDNS(c, store)
+			assert.Equal(t, http.StatusNotFound, w.Code)
+		})
+	}
+}
+
+func TestAcceptDNSRequest(t *testing.T) {
+	store := cache.New(cache.NoExpiration, cache.NoExpiration)
+
+	tests := []struct {
+		name   string
+		accept string
+		want   string
+	}{
+		{
+			name:   "returns json dns data",
+			accept: "application/json",
+			want:   jsonDNSIPv4,
+		},
+		{
+			name:   "return plan text dns data",
+			accept: "text/plain",
+			want:   plainDNSIPv4,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req, _ := http.NewRequest("GET", "/", nil)
+			u := uuid.New().String()
+			req.Host = u + "." + domain
+			req.Header.Add("Accept", tt.accept)
+
+			w := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(w)
+			c.Request = req
+
+			store.Add(u, testIP.ipv4, cache.DefaultExpiration)
+			handleDNS(c, store)
+
+			assert.Equal(t, http.StatusOK, w.Code)
+			assert.Equal(t, tt.want, w.Body.String())
+		})
+	}
+}

router/generic.go

@@ -7,26 +7,28 @@ import (
 
 	"github.com/dcarrillo/whatismyip/internal/httputils"
 	"github.com/dcarrillo/whatismyip/internal/setting"
-	"github.com/dcarrillo/whatismyip/service"
 	"github.com/gin-gonic/gin"
 )
 
-// JSONResponse maps data as json
+type GeoResponse struct {
+	Country         string  `json:"country,omitempty"`
+	CountryCode     string  `json:"country_code,omitempty"`
+	City            string  `json:"city,omitempty"`
+	Latitude        float64 `json:"latitude,omitempty"`
+	Longitude       float64 `json:"longitude,omitempty"`
+	PostalCode      string  `json:"postal_code,omitempty"`
+	TimeZone        string  `json:"time_zone,omitempty"`
+	ASN             uint    `json:"asn,omitempty"`
+	ASNOrganization string  `json:"asn_organization,omitempty"`
+}
+
 type JSONResponse struct {
 	IP         string      `json:"ip"`
 	IPVersion  byte        `json:"ip_version"`
 	ClientPort string      `json:"client_port"`
-	Country         string      `json:"country"`
-	CountryCode     string      `json:"country_code"`
-	City            string      `json:"city"`
-	Latitude        float64     `json:"latitude"`
-	Longitude       float64     `json:"longitude"`
-	PostalCode      string      `json:"postal_code"`
-	TimeZone        string      `json:"time_zone"`
-	ASN             uint        `json:"asn"`
-	ASNOrganization string      `json:"asn_organization"`
 	Host       string      `json:"host"`
 	Headers    http.Header `json:"headers"`
+	GeoResponse
 }
 
 func getRoot(ctx *gin.Context) {
@@ -67,16 +69,14 @@ func getClientPortAsString(ctx *gin.Context) {
 }
 
 func getAllAsString(ctx *gin.Context) {
-	output := "IP: " + ctx.ClientIP() + "\n"
+	ip := net.ParseIP(ctx.ClientIP())
+
+	output := "IP: " + ip.String() + "\n"
 	output += "Client Port: " + getClientPort(ctx) + "\n"
 
-	r := service.Geo{IP: net.ParseIP(ctx.ClientIP())}
+	if geoSvc != nil {
-	if record := r.LookUpCity(); record != nil {
+		output += geoCityRecordToString(geoSvc.LookUpCity(ip)) + "\n"
-		output += geoCityRecordToString(record) + "\n"
+		output += geoASNRecordToString(geoSvc.LookUpASN(ip)) + "\n"
-	}
-
-	if record := r.LookUpASN(); record != nil {
-		output += geoASNRecordToString(record) + "\n"
 	}
 
 	h := httputils.GetHeadersWithoutTrustedHeaders(ctx)
@@ -91,18 +91,19 @@ func getJSON(ctx *gin.Context) {
 }
 
 func jsonOutput(ctx *gin.Context) JSONResponse {
-	ip := service.Geo{IP: net.ParseIP(ctx.ClientIP())}
+	ip := net.ParseIP(ctx.ClientIP())
-	asnRecord := ip.LookUpASN()
+
-	cityRecord := ip.LookUpCity()
 	var version byte = 4
-	if p := net.ParseIP(ctx.ClientIP()).To4(); p == nil {
+	if p := ip.To4(); p == nil {
 		version = 6
 	}
 
-	return JSONResponse{
+	geoResp := GeoResponse{}
-		IP:              ctx.ClientIP(),
+	if geoSvc != nil {
-		IPVersion:       version,
+		cityRecord := geoSvc.LookUpCity(ip)
-		ClientPort:      getClientPort(ctx),
+		asnRecord := geoSvc.LookUpASN(ip)
+
+		geoResp = GeoResponse{
 			Country:         cityRecord.Country.Names["en"],
 			CountryCode:     cityRecord.Country.ISOCode,
 			City:            cityRecord.City.Names["en"],
@@ -112,7 +113,15 @@ func jsonOutput(ctx *gin.Context) JSONResponse {
 			TimeZone:        cityRecord.Location.TimeZone,
 			ASN:             asnRecord.AutonomousSystemNumber,
 			ASNOrganization: asnRecord.AutonomousSystemOrganization,
+		}
+	}
+
+	return JSONResponse{
+		IP:          ip.String(),
+		IPVersion:   version,
+		ClientPort:  getClientPort(ctx),
 		Host:        ctx.Request.Host,
 		Headers:     httputils.GetHeadersWithoutTrustedHeaders(ctx),
+		GeoResponse: geoResp,
 	}
 }

router/geo.go

@@ -8,7 +8,6 @@ import (
 	"strings"
 
 	"github.com/dcarrillo/whatismyip/models"
-	"github.com/dcarrillo/whatismyip/service"
 	"github.com/gin-gonic/gin"
 )
 
@@ -83,10 +82,13 @@ var asnOutput = map[string]asnDataFormatter{
 }
 
 func getGeoAsString(ctx *gin.Context) {
-	field := strings.ToLower(ctx.Params.ByName("field"))
+	if geoSvc == nil {
-	ip := service.Geo{IP: net.ParseIP(ctx.ClientIP())}
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
-	record := ip.LookUpCity()
+		return
+	}
 
+	field := strings.ToLower(ctx.Params.ByName("field"))
+	record := geoSvc.LookUpCity(net.ParseIP(ctx.ClientIP()))
 	if field == "" {
 		ctx.String(http.StatusOK, geoCityRecordToString(record))
 	} else if g, ok := geoOutput[field]; ok {
@@ -97,10 +99,12 @@ func getGeoAsString(ctx *gin.Context) {
 }
 
 func getASNAsString(ctx *gin.Context) {
+	if geoSvc == nil {
+		ctx.String(http.StatusNotFound, http.StatusText(http.StatusNotFound))
+		return
+	}
 	field := strings.ToLower(ctx.Params.ByName("field"))
-	ip := service.Geo{IP: net.ParseIP(ctx.ClientIP())}
+	record := geoSvc.LookUpASN(net.ParseIP(ctx.ClientIP()))
-	record := ip.LookUpASN()
-
 	if field == "" {
 		ctx.String(http.StatusOK, geoASNRecordToString(record))
 	} else if g, ok := asnOutput[field]; ok {

router/port_scanner.go

@@ -0,0 +1,54 @@
+package router
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"strconv"
+
+	"github.com/dcarrillo/whatismyip/service"
+	"github.com/gin-gonic/gin"
+)
+
+type JSONScanResponse struct {
+	IP        string `json:"ip"`
+	Port      int    `json:"port"`
+	Reachable bool   `json:"reachable"`
+	Reason    string `json:"reason"`
+}
+
+func scanTCPPort(ctx *gin.Context) {
+	port, err := strconv.Atoi(ctx.Params.ByName("port"))
+	if err == nil && (port < 1 || port > 65535) {
+		err = fmt.Errorf("%d is not a valid port number", port)
+	}
+	if err != nil {
+		ctx.JSON(http.StatusBadRequest, JSONScanResponse{
+			Reason: err.Error(),
+		})
+		return
+	}
+
+	add := net.TCPAddr{
+		IP:   net.ParseIP(ctx.ClientIP()),
+		Port: port,
+	}
+
+	scan := service.PortScanner{
+		Address: &add,
+	}
+
+	isOpen, err := scan.IsPortOpen()
+	reason := ""
+	if err != nil {
+		reason = err.Error()
+	}
+
+	response := JSONScanResponse{
+		IP:        ctx.ClientIP(),
+		Port:      port,
+		Reachable: isOpen,
+		Reason:    reason,
+	}
+	ctx.JSON(http.StatusOK, response)
+}

router/setup.go

@@ -5,10 +5,12 @@ import (
 	"log"
 
 	"github.com/dcarrillo/whatismyip/internal/setting"
+	"github.com/dcarrillo/whatismyip/service"
 	"github.com/gin-gonic/gin"
 )
 
-// SetupTemplate reads and parses a template from file
+var geoSvc *service.Geo
+
 func SetupTemplate(r *gin.Engine) {
 	if setting.App.TemplatePath == "" {
 		t, _ := template.New("home").Parse(home)
@@ -19,9 +21,10 @@ func SetupTemplate(r *gin.Engine) {
 	}
 }
 
-// Setup defines the endpoints
+func Setup(r *gin.Engine, geo *service.Geo) {
-func Setup(r *gin.Engine) {
+	geoSvc = geo
 	r.GET("/", getRoot)
+	r.GET("/scan/tcp/:port", scanTCPPort)
 	r.GET("/client-port", getClientPortAsString)
 	r.GET("/geo", getGeoAsString)
 	r.GET("/geo/:field", getGeoAsString)

router/setup_test.go

@@ -1,10 +1,11 @@
 package router
 
 import (
+	"context"
 	"os"
 	"testing"
 
-	"github.com/dcarrillo/whatismyip/models"
+	"github.com/dcarrillo/whatismyip/service"
 	"github.com/gin-gonic/gin"
 )
 
@@ -34,19 +35,23 @@ var (
 		text: "text/plain; charset=utf-8",
 		json: "application/json; charset=utf-8",
 	}
-	jsonIPv4 = `{"client_port":"1001","ip":"81.2.69.192","ip_version":4,"country":"United Kingdom","country_code":"GB","city":"London","latitude":51.5142,"longitude":-0.0931,"postal_code":"","time_zone":"Europe/London","asn":0,"asn_organization":"","host":"test", "headers": {}}`
+	jsonIPv4     = `{"client_port":"1001","ip":"81.2.69.192","ip_version":4,"country":"United Kingdom","country_code":"GB","city":"London","latitude":51.5142,"longitude":-0.0931,"time_zone":"Europe/London","host":"test", "headers": {}}`
-	jsonIPv6 = `{"asn":3352, "asn_organization":"TELEFONICA DE ESPANA", "city":"", "client_port":"1001", "country":"", "country_code":"", "host":"test", "ip":"2a02:9000::1", "ip_version":6, "latitude":0, "longitude":0, "postal_code":"", "time_zone":"", "headers": {}}`
+	jsonIPv6     = `{"asn":3352,"asn_organization":"TELEFONICA DE ESPANA","client_port":"1001","host":"test","ip":"2a02:9000::1","ip_version":6,"headers": {}}`
+	jsonDNSIPv4  = `{"dns":{"ip":"81.2.69.192","country":"United Kingdom"}}`
+	plainDNSIPv4 = "81.2.69.192 (United Kingdom / )\n"
 )
 
-const trustedHeader = "X-Real-IP"
+const (
-const trustedPortHeader = "X-Real-Port"
+	trustedHeader     = "X-Real-IP"
+	trustedPortHeader = "X-Real-Port"
+	domain            = "dns.example.com"
+)
 
 func TestMain(m *testing.M) {
 	app = gin.Default()
 	app.TrustedPlatform = trustedHeader
-	models.Setup("../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
+	svc, _ := service.NewGeo(context.Background(), "../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
-	Setup(app)
+	Setup(app, svc)
-	defer models.CloseDBs()
 
 	os.Exit(m.Run())
 }

router/templates_test.go

@@ -65,6 +65,9 @@ func TestDefaultTemplate(t *testing.T) {
 		IP:         "127.0.0.1",
 		IPVersion:  4,
 		ClientPort: "1000",
+		Host:       "localhost",
+		Headers:    req.Header,
+		GeoResponse: GeoResponse{
 			Country:         "A Country",
 			CountryCode:     "XX",
 			City:            "A City",
@@ -74,8 +77,7 @@ func TestDefaultTemplate(t *testing.T) {
 			TimeZone:        "My/Timezone",
 			ASN:             0,
 			ASNOrganization: "My ISP",
-		Host:            "localhost",
+		},
-		Headers:         req.Header,
 	}
 
 	buf := &bytes.Buffer{}

server/dns.go

@@ -0,0 +1,48 @@
+package server
+
+import (
+	"context"
+	"log"
+	"strconv"
+
+	"github.com/miekg/dns"
+)
+
+const port = 53
+
+type DNS struct {
+	server  *dns.Server
+	handler *dns.Handler
+	ctx     context.Context
+}
+
+func NewDNSServer(ctx context.Context, handler dns.Handler) *DNS {
+	return &DNS{
+		handler: &handler,
+		ctx:     ctx,
+	}
+}
+
+func (d *DNS) Start() {
+	d.server = &dns.Server{
+		Addr:    ":" + strconv.Itoa(port),
+		Net:     "udp",
+		Handler: *d.handler,
+		// UDPSize:   65535,
+		// ReusePort: true,
+	}
+
+	log.Printf("Starting DNS server listening on :%d (udp)", port)
+	go func() {
+		if err := d.server.ListenAndServe(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+}
+
+func (d *DNS) Stop() {
+	log.Print("Stopping DNS server...")
+	if err := d.server.Shutdown(); err != nil {
+		log.Printf("DNS server forced to shutdown: %s", err)
+	}
+}

server/quic.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	"errors"
 	"log"
 	"net/http"
 
@@ -9,20 +10,20 @@ import (
 	"github.com/quic-go/quic-go/http3"
 )
 
-type QuicServer struct {
+type Quic struct {
 	server    *http3.Server
-	tlsServer *TLSServer
+	tlsServer *TLS
 	ctx       context.Context
 }
 
-func NewQuicServer(ctx context.Context, tlsServer *TLSServer) *QuicServer {
+func NewQuicServer(ctx context.Context, tlsServer *TLS) *Quic {
-	return &QuicServer{
+	return &Quic{
 		tlsServer: tlsServer,
 		ctx:       ctx,
 	}
 }
 
-func (q *QuicServer) Start() {
+func (q *Quic) Start() {
 	q.server = &http3.Server{
 		Addr:    setting.App.TLSAddress,
 		Handler: q.tlsServer.server.Handler,
@@ -30,7 +31,7 @@ func (q *QuicServer) Start() {
 
 	parentHandler := q.tlsServer.server.Handler
 	q.tlsServer.server.Handler = http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
-		if err := q.server.SetQuicHeaders(rw.Header()); err != nil {
+		if err := q.server.SetQUICHeaders(rw.Header()); err != nil {
 			log.Fatal(err)
 		}
 
@@ -40,15 +41,15 @@ func (q *QuicServer) Start() {
 	log.Printf("Starting QUIC server listening on %s (udp)", setting.App.TLSAddress)
 	go func() {
 		if err := q.server.ListenAndServeTLS(setting.App.TLSCrtPath, setting.App.TLSKeyPath); err != nil &&
-			err.Error() != "quic: Server closed" {
+			!errors.Is(err, http.ErrServerClosed) {
 			log.Fatal(err)
 		}
 	}()
 }
 
-func (q *QuicServer) Stop() {
+func (q *Quic) Stop() {
-	log.Printf("Stopping QUIC server...")
+	log.Print("Stopping QUIC server...")
 	if err := q.server.Close(); err != nil {
-		log.Printf("QUIC server forced to shutdown")
+		log.Print("QUIC server forced to shutdown")
 	}
 }

server/server.go

@@ -2,14 +2,11 @@ package server
 
 import (
 	"log"
-	"net/http"
 	"os"
 	"os/signal"
 	"syscall"
 
-	"github.com/dcarrillo/whatismyip/internal/setting"
+	"github.com/dcarrillo/whatismyip/service"
-	"github.com/dcarrillo/whatismyip/models"
-	"golang.org/x/net/context"
 )
 
 type Server interface {
@@ -17,80 +14,52 @@ type Server interface {
 	Stop()
 }
 
-type Factory struct {
+type Manager struct {
-	tcpServer  *TCPServer
+	servers []Server
-	tlsServer  *TLSServer
+	geoSvc  *service.Geo
-	quicServer *QuicServer
 }
 
-func Setup(ctx context.Context, handler http.Handler) *Factory {
+func Setup(servers []Server, geoSvc *service.Geo) *Manager {
-	var tcpServer *TCPServer
+	return &Manager{
-	var tlsServer *TLSServer
+		servers: servers,
-	var quicServer *QuicServer
+		geoSvc:  geoSvc,
-
-	if setting.App.BindAddress != "" {
-		tcpServer = NewTCPServer(ctx, &handler)
-	}
-
-	if setting.App.TLSAddress != "" {
-		tlsServer = NewTLSServer(ctx, &handler)
-		if setting.App.EnableHTTP3 {
-			quicServer = NewQuicServer(ctx, tlsServer)
-		}
-	}
-
-	return &Factory{
-		tcpServer:  tcpServer,
-		tlsServer:  tlsServer,
-		quicServer: quicServer,
 	}
 }
 
-func (f *Factory) Run() {
+func (m *Manager) Run() {
-	f.start()
+	m.start()
 
-	signalChan := make(chan os.Signal, 3)
+	signalChan := make(chan os.Signal, len(m.servers))
 	signal.Notify(signalChan, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
 	var s os.Signal
 	for {
 		s = <-signalChan
 
 		if s == syscall.SIGHUP {
-			f.stop()
+			m.stop()
-			models.CloseDBs()
+			if m.geoSvc != nil {
-			models.Setup(setting.App.GeodbPath.City, setting.App.GeodbPath.ASN)
+				m.geoSvc.Reload()
-			f.start()
+			}
+			m.start()
 		} else {
-			log.Printf("Shutting down...")
+			log.Print("Shutting down...")
-			f.stop()
+			if m.geoSvc != nil {
-			models.CloseDBs()
+				m.geoSvc.Shutdown()
+			}
+			m.stop()
 			break
 		}
 	}
 }
 
-func (f *Factory) start() {
+func (m *Manager) start() {
-	if f.tcpServer != nil {
+	for _, s := range m.servers {
-		f.tcpServer.Start()
+		s.Start()
-	}
-
-	if f.tlsServer != nil {
-		f.tlsServer.Start()
-		if f.quicServer != nil {
-			f.quicServer.Start()
-		}
 	}
 }
 
-func (f *Factory) stop() {
+func (m *Manager) stop() {
-	if f.tcpServer != nil {
+	for _, s := range m.servers {
-		f.tcpServer.Stop()
+		s.Stop()
-	}
-
-	if f.tlsServer != nil {
-		if f.quicServer != nil {
-			f.quicServer.Stop()
-		}
-		f.tlsServer.Stop()
 	}
 }

server/tcp.go

@@ -9,20 +9,20 @@ import (
 	"github.com/dcarrillo/whatismyip/internal/setting"
 )
 
-type TCPServer struct {
+type TCP struct {
 	server  *http.Server
 	handler *http.Handler
 	ctx     context.Context
 }
 
-func NewTCPServer(ctx context.Context, handler *http.Handler) *TCPServer {
+func NewTCPServer(ctx context.Context, handler *http.Handler) *TCP {
-	return &TCPServer{
+	return &TCP{
 		handler: handler,
 		ctx:     ctx,
 	}
 }
 
-func (t *TCPServer) Start() {
+func (t *TCP) Start() {
 	t.server = &http.Server{
 		Addr:         setting.App.BindAddress,
 		Handler:      *t.handler,
@@ -38,8 +38,8 @@ func (t *TCPServer) Start() {
 	}()
 }
 
-func (t *TCPServer) Stop() {
+func (t *TCP) Stop() {
-	log.Printf("Stopping TCP server...")
+	log.Print("Stopping TCP server...")
 	if err := t.server.Shutdown(t.ctx); err != nil {
 		log.Printf("TCP server forced to shutdown: %s", err)
 	}

server/tls.go

@@ -9,20 +9,20 @@ import (
 	"github.com/dcarrillo/whatismyip/internal/setting"
 )
 
-type TLSServer struct {
+type TLS struct {
 	server  *http.Server
 	handler *http.Handler
 	ctx     context.Context
 }
 
-func NewTLSServer(ctx context.Context, handler *http.Handler) *TLSServer {
+func NewTLSServer(ctx context.Context, handler *http.Handler) *TLS {
-	return &TLSServer{
+	return &TLS{
 		handler: handler,
 		ctx:     ctx,
 	}
 }
 
-func (t *TLSServer) Start() {
+func (t *TLS) Start() {
 	t.server = &http.Server{
 		Addr:         setting.App.TLSAddress,
 		Handler:      *t.handler,
@@ -39,8 +39,8 @@ func (t *TLSServer) Start() {
 	}()
 }
 
-func (t *TLSServer) Stop() {
+func (t *TLS) Stop() {
-	log.Printf("Stopping TLS server...")
+	log.Print("Stopping TLS server...")
 	if err := t.server.Shutdown(t.ctx); err != nil {
 		log.Printf("TLS server forced to shutdown: %s", err)
 	}

service/geo.go

@@ -1,37 +1,73 @@
 package service
 
 import (
+	"context"
 	"log"
 	"net"
+	"sync"
 
 	"github.com/dcarrillo/whatismyip/models"
 )
 
-// Geo defines a base type for lookups
 type Geo struct {
-	IP net.IP
+	ctx    context.Context
+	cancel context.CancelFunc
+	db     *models.GeoDB
+	mu     sync.RWMutex
 }
 
-// LookUpCity queries the database for city data related to the given IP
+func NewGeo(ctx context.Context, cityPath string, asnPath string) (*Geo, error) {
-func (g *Geo) LookUpCity() *models.GeoRecord {
+	ctx, cancel := context.WithCancel(ctx)
-	record := &models.GeoRecord{}
+
-	err := record.LookUp(g.IP)
+	db, err := models.Setup(cityPath, asnPath)
 	if err != nil {
-		log.Println(err)
+		cancel()
+		return nil, err
+	}
+
+	geo := &Geo{
+		ctx:    ctx,
+		cancel: cancel,
+		db:     db,
+	}
+
+	return geo, nil
+}
+
+func (g *Geo) LookUpCity(ip net.IP) *models.GeoRecord {
+	record, err := g.db.LookupCity(ip)
+	if err != nil {
+		log.Print(err)
 		return nil
 	}
 
 	return record
 }
 
-// LookUpASN queries the database for ASN data related to the given IP
+func (g *Geo) LookUpASN(ip net.IP) *models.ASNRecord {
-func (g *Geo) LookUpASN() *models.ASNRecord {
+	record, err := g.db.LookupASN(ip)
-	record := &models.ASNRecord{}
-	err := record.LookUp(g.IP)
 	if err != nil {
-		log.Println(err)
+		log.Print(err)
 		return nil
 	}
 
 	return record
 }
+
+func (g *Geo) Shutdown() {
+	g.cancel()
+	g.db.CloseDBs()
+}
+
+func (g *Geo) Reload() {
+	if err := g.ctx.Err(); err != nil {
+		log.Printf("Skipping reload, service is shutting down: %v", err)
+		return
+	}
+
+	g.mu.Lock()
+	defer g.mu.Unlock()
+
+	g.db.Reload()
+	log.Print("Geo database reloaded")
+}

service/geo_test.go

@@ -1,36 +1,33 @@
 package service
 
 import (
+	"context"
 	"net"
 	"os"
 	"testing"
 
-	"github.com/dcarrillo/whatismyip/models"
 	"github.com/stretchr/testify/assert"
 )
 
+var geoSvc *Geo
+
 func TestMain(m *testing.M) {
-	models.Setup("../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
+	geoSvc, _ = NewGeo(context.Background(), "../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
-	defer models.CloseDBs()
 	os.Exit(m.Run())
 }
 
 func TestCityLookup(t *testing.T) {
-	ip := Geo{IP: net.ParseIP("error")}
+	c := geoSvc.LookUpCity(net.ParseIP("error"))
-	c := ip.LookUpCity()
 	assert.Nil(t, c)
 
-	ip = Geo{IP: net.ParseIP("1.1.1.1")}
+	c = geoSvc.LookUpCity(net.ParseIP("1.1.1.1"))
-	c = ip.LookUpCity()
 	assert.NotNil(t, c)
 }
 
 func TestASNLookup(t *testing.T) {
-	ip := Geo{IP: net.ParseIP("error")}
+	a := geoSvc.LookUpASN(net.ParseIP("error"))
-	a := ip.LookUpASN()
 	assert.Nil(t, a)
 
-	ip = Geo{IP: net.ParseIP("1.1.1.1")}
+	a = geoSvc.LookUpASN(net.ParseIP("1.1.1.1"))
-	a = ip.LookUpASN()
 	assert.NotNil(t, a)
 }

service/port_scanner.go

@@ -0,0 +1,24 @@
+package service
+
+import (
+	"net"
+	"time"
+)
+
+const scannerTimeOut = 3 * time.Second
+
+type PortScanner struct {
+	Address net.Addr
+}
+
+func (p *PortScanner) IsPortOpen() (bool, error) {
+	conn, err := net.DialTimeout(p.Address.Network(), p.Address.String(), scannerTimeOut)
+	if err != nil {
+		return false, err
+	}
+	if conn != nil {
+		defer conn.Close()
+	}
+
+	return true, nil
+}

test/Dockerfile

@@ -0,0 +1,15 @@
+FROM golang:1.24-alpine AS builder
+
+ARG ARG_VERSION
+ENV VERSION=$ARG_VERSION
+
+WORKDIR /app
+COPY . .
+
+FROM builder AS build-test-app
+RUN CGO_ENABLED=0 \
+    go build -ldflags="-s -w" -o whatismyip ./cmd
+
+FROM scratch AS test
+COPY --from=build-test-app /app/whatismyip /usr/bin/
+ENTRYPOINT ["whatismyip"]

test/resolver.yml

@@ -0,0 +1,10 @@
+---
+domain: dns.example.com
+redirect_port: ":8000"
+resource_records:
+  - "1800 IN SOA xns.example.com. hostmaster.example.com. 1 10000 2400 604800 1800"
+  - "3600 IN NS xns.example.com."
+ipv4:
+  - "127.0.0.2"
+ipv6:
+  - "aaa:aaa:aaa:aaaa::1"