Add basic DNS and DNS-over-TLS implementation

- add random and incremental DNS fallback strategy
- add option to handle DNS requests based on regex patterns
- made Makefiles plugin independent
- extended config
- set default plugins directory in Dockerfile

Dockerfile

@@ -32,6 +32,8 @@ RUN make CONTAINER=yes
 
 FROM scratch
 
+ENV INETMOCK_PLUGINS_DIRECTORY=/app/plugins/
+
 WORKDIR /app
 
 COPY --from=build /etc/passwd /etc/group /etc/

config.yaml

@@ -38,4 +38,38 @@ endpoints:
       certCachePath: /tmp/inetmock/
       target:
         ipAddress: 127.0.0.1
-        port: 80
+        port: 80
+  plainDns:
+    handler: dns_mock
+    listenAddress: 0.0.0.0
+    port: 53
+    options:
+      fallback:
+        strategy: incremental
+        args:
+          startIP: 10.0.0.0
+      rules:
+        - pattern: ".*\\.google\\.com"
+          response: 1.1.1.1
+        - pattern: ".*\\.reddit\\.com"
+          response: 2.2.2.2
+  dnsOverTlsDowngrade:
+    handler: tls_interceptor
+    listenAddress: 0.0.0.0
+    port: 853
+    options:
+      ecdsaCurve: P256
+      validity:
+        ca:
+          notBeforeRelative: 17520h
+          notAfterRelative: 17520h
+        domain:
+          notBeforeRelative: 168h
+          notAfterRelative: 168h
+      rootCaCert:
+        publicKey: ./ca.pem
+        privateKey: ./ca.key
+      certCachePath: /tmp/inetmock/
+      target:
+        ipAddress: 127.0.0.1
+        port: 53

go.mod

@@ -3,10 +3,10 @@ module github.com/baez90/inetmock
 go 1.13
 
 require (
+	github.com/miekg/dns v1.1.29
 	github.com/spf13/cobra v0.0.6
 	github.com/spf13/pflag v1.0.5
 	github.com/spf13/viper v1.4.0
 	go.uber.org/zap v1.14.1
-	golang.org/x/tools v0.0.0-20191127201027-ecd32218bd7f // indirect
 	gopkg.in/yaml.v2 v2.2.8 // indirect
 )

go.sum

@@ -60,6 +60,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/magiconair/properties v1.8.0 h1:LLgXmsheXeRoUOBOjtwPQCWIYqM/LU1ayDtDePerRcY=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
+github.com/miekg/dns v1.1.29 h1:xHBEhR+t5RzcFJjBLJlax2daXOrTYtr9z4WdKEfWFzg=
+github.com/miekg/dns v1.1.29/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
@@ -129,11 +131,14 @@ golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnf
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529 h1:iMGN4xG0cnqj3t+zOM8wUB0BiPKHEwSxEZCvzcbZuvk=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
+golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -141,10 +146,13 @@ golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190522155817-f3200d17e092/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478 h1:l5EDrHhldLYb3ZRHDUhXF7Om7MvYXnkV9/iQNo1lX6g=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -154,6 +162,8 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe h1:6fAMxZRR6sl1Uq8U61gxU+kPTs2tR8uOySCbBP7BN/M=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@@ -164,9 +174,10 @@ golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgw
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5 h1:hKsoRgsbwY1NafxrwTs+k64bikrLBkAgPir1TNCj3Zs=
 golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20191127201027-ecd32218bd7f h1:3MlESg/jvTr87F4ttA/q4B+uhe/q6qleC9/DP+IwQmY=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425 h1:VvQyQJN0tSuecqgcIxMWnnfG5kSmgy9KZR9sW3W5QeA=
-golang.org/x/tools v0.0.0-20191127201027-ecd32218bd7f/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=

pkg/plugins/dns_mock/Makefile

@@ -0,0 +1,44 @@
+VERSION = $(shell git describe --dirty --tags --always)
+DIR = $(dir $(realpath $(firstword $(MAKEFILE_LIST))))
+PKGS = $(shell go list ./...)
+TEST_PKGS = $(shell find . -type f -name "*_test.go" -printf '%h\n' | sort -u)
+GOARGS = GOOS=linux GOARCH=amd64
+GO_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s"
+GO_CONTAINER_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s" -a -installsuffix cgo
+GO_DEBUG_BUILD_ARGS = -buildmode=plugin -gcflags "all=-N -l"
+PLUGIN_NAME = $(shell basename $(DIR)).so
+OUT_DIR = $(DIR)../../../plugins
+DEBUG_PORT = 2345
+
+.PHONY: deps format compile test cli-cover-report html-cover-report
+
+all: format compile test
+
+deps:
+	@go mod tidy
+	@go build -buildmode=plugin -v $(DIR)...
+
+format:
+	@go fmt $(PKGS)
+
+compile: deps
+	@mkdir -p $(OUT_DIR)
+ifdef DEBUG
+	@echo 'Compiling for debugging...'
+	@$(GOARGS) go build $(GO_DEBUG_BUILD_ARGS) -o $(OUT_DIR)/$(PLUGIN_NAME) $(DIR)
+else ifdef CONTAINER
+	@$(GOARGS) go build $(GO_CONTAINER_BUILD_ARGS) -o $(OUT_DIR)/$(PLUGIN_NAME) $(DIR)
+else
+	@$(GOARGS) go build $(GO_BUILD_ARGS) -o $(OUT_DIR)/$(PLUGIN_NAMEs) $(DIR)
+endif
+
+test:
+	@go test -coverprofile=./cov-raw.out -v $(TEST_PKGS)
+	@cat ./cov-raw.out | grep -v "generated" > ./cov.out
+	@rm -f $(DIR)$(PLUGIN_NAME)
+
+cli-cover-report:
+	@go tool cover -func=cov.out
+
+html-cover-report:
+	@go tool cover -html=cov.out -o .coverage.html

pkg/plugins/dns_mock/fallback.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"encoding/binary"
+	"github.com/spf13/viper"
+	"math"
+	"math/rand"
+	"net"
+	"unsafe"
+)
+
+const (
+	randomIPStrategyName      = "random"
+	incrementalIPStrategyName = "incremental"
+	startIPConfigKey          = "startIP"
+)
+
+var (
+	fallbackStrategies map[string]ResolverFactory
+)
+
+type ResolverFactory func(conf *viper.Viper) ResolverFallback
+
+func init() {
+	fallbackStrategies = make(map[string]ResolverFactory)
+	fallbackStrategies[incrementalIPStrategyName] = func(conf *viper.Viper) ResolverFallback {
+		return &incrementalIPFallback{
+			latestIp: ipToInt32(net.ParseIP(conf.GetString(startIPConfigKey))),
+		}
+	}
+	fallbackStrategies[randomIPStrategyName] = func(conf *viper.Viper) ResolverFallback {
+		return &randomIPFallback{}
+	}
+}
+
+func CreateResolverFallback(name string, config *viper.Viper) ResolverFallback {
+	if factory, ok := fallbackStrategies[name]; ok {
+		return factory(config)
+	} else {
+		return fallbackStrategies[randomIPStrategyName](config)
+	}
+}
+
+type ResolverFallback interface {
+	GetIP() net.IP
+}
+
+type incrementalIPFallback struct {
+	latestIp uint32
+}
+
+func (i *incrementalIPFallback) GetIP() net.IP {
+	if i.latestIp < math.MaxInt32 {
+		i.latestIp += 1
+	}
+	return uint32ToIP(i.latestIp)
+}
+
+type randomIPFallback struct {
+}
+
+func (randomIPFallback) GetIP() net.IP {
+	return uint32ToIP(uint32(rand.Int31()))
+}
+
+func uint32ToIP(i uint32) net.IP {
+	bytes := (*[4]byte)(unsafe.Pointer(&i))[:]
+	return net.IPv4(bytes[3], bytes[2], bytes[1], bytes[0])
+}
+
+func ipToInt32(ip net.IP) uint32 {
+	v4 := ip.To4()
+	result := binary.BigEndian.Uint32(v4)
+	return result
+}

pkg/plugins/dns_mock/fallback_test.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"net"
+	"reflect"
+	"testing"
+)
+
+func Test_randomIPFallback_GetIP(t *testing.T) {
+	ra := randomIPFallback{}
+	for i := 0; i < 1000; i++ {
+		if got := ra.GetIP(); reflect.DeepEqual(got, net.IP{}) {
+			t.Errorf("GetIP() = %v", got)
+		}
+	}
+}
+
+func Test_incrementalIPFallback_GetIP(t *testing.T) {
+	type fields struct {
+		latestIp uint32
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   []net.IP
+	}{
+		{
+			name: "Expect the next icremental IP",
+			fields: fields{
+				latestIp: 167772160,
+			},
+			want: []net.IP{
+				net.IPv4(10, 0, 0, 1),
+			},
+		},
+		{
+			name: "Expect a sequence of 5",
+			fields: fields{
+				latestIp: 167772160,
+			},
+			want: []net.IP{
+				net.IPv4(10, 0, 0, 1),
+				net.IPv4(10, 0, 0, 2),
+				net.IPv4(10, 0, 0, 3),
+				net.IPv4(10, 0, 0, 4),
+				net.IPv4(10, 0, 0, 5),
+			},
+		},
+		{
+			name: "Expect next block to be incremented",
+			fields: fields{
+				latestIp: 167772413,
+			},
+			want: []net.IP{
+				net.IPv4(10, 0, 0, 254),
+				net.IPv4(10, 0, 0, 255),
+				net.IPv4(10, 0, 1, 0),
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			i := &incrementalIPFallback{
+				latestIp: tt.fields.latestIp,
+			}
+			for k := 0; k < len(tt.want); k++ {
+				if got := i.GetIP(); !reflect.DeepEqual(got, tt.want[k]) {
+					t.Errorf("GetIP() = %v, want %v", got, tt.want[k])
+				}
+			}
+		})
+	}
+}
+
+func Test_ipToInt32(t *testing.T) {
+	type args struct {
+		ip net.IP
+	}
+	tests := []struct {
+		name string
+		args args
+		want uint32
+	}{
+		{
+			name: "Convert 188.193.106.113 to int",
+			args: args{
+				ip: net.ParseIP("188.193.106.113"),
+			},
+			want: 3166792305,
+		},
+		{
+			name: "Convert 192.168.178.10 to int",
+			args: args{
+				ip: net.ParseIP("192.168.178.10"),
+			},
+			want: 3232281098,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ipToInt32(tt.args.ip); got != tt.want {
+				t.Errorf("ipToInt32() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

pkg/plugins/dns_mock/init.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"github.com/baez90/inetmock/internal/plugins"
+	"github.com/baez90/inetmock/pkg/api"
+	"github.com/baez90/inetmock/pkg/logging"
+	"go.uber.org/zap"
+)
+
+const (
+	name = "dns_mock"
+)
+
+func init() {
+	logger, _ := logging.CreateLogger()
+	logger = logger.With(
+		zap.String("ProtocolHandler", name),
+	)
+
+	plugins.Registry().RegisterHandler(name, func() api.ProtocolHandler {
+		return &dnsHandler{
+			logger: logger,
+		}
+	})
+}

pkg/plugins/dns_mock/main.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"fmt"
+	"github.com/baez90/inetmock/internal/config"
+	"github.com/miekg/dns"
+	"go.uber.org/zap"
+	"sync"
+)
+
+type dnsHandler struct {
+	logger    *zap.Logger
+	dnsServer []*dns.Server
+}
+
+func (d *dnsHandler) Run(config config.HandlerConfig) {
+	options := loadFromConfig(config.Options())
+	addr := fmt.Sprintf("%s:%d", config.ListenAddress(), config.Port())
+
+	handler := &regexHandler{
+		fallback: options.Fallback,
+		logger:   d.logger,
+	}
+
+	for _, rule := range options.Rules {
+		d.logger.Info(
+			"register DNS rule",
+			zap.String("pattern", rule.pattern.String()),
+			zap.String("response", rule.response.String()),
+		)
+		handler.AddRule(rule)
+	}
+
+	d.logger = d.logger.With(
+		zap.String("address", addr),
+	)
+
+	d.dnsServer = []*dns.Server{
+		{
+			Addr:    addr,
+			Net:     "udp",
+			Handler: handler,
+		},
+		{
+			Addr:    addr,
+			Net:     "tcp",
+			Handler: handler,
+		},
+	}
+
+	for _, dnsServer := range d.dnsServer {
+		go d.startServer(dnsServer)
+	}
+}
+
+func (d *dnsHandler) startServer(dnsServer *dns.Server) {
+	if err := dnsServer.ListenAndServe(); err != nil {
+		d.logger.Error(
+			"failed to start DNS server listener",
+			zap.Error(err),
+		)
+	}
+}
+
+func (d *dnsHandler) Shutdown(wg *sync.WaitGroup) {
+	for _, dnsServer := range d.dnsServer {
+		if err := dnsServer.Shutdown(); err != nil {
+			d.logger.Error(
+				"failed to shutdown server",
+				zap.Error(err),
+			)
+		}
+	}
+	wg.Done()
+}

pkg/plugins/dns_mock/protocol_options.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"github.com/spf13/viper"
+	"net"
+	"regexp"
+)
+
+const (
+	rulesConfigKey            = "rules"
+	patternConfigKey          = "pattern"
+	responseConfigKey         = "response"
+	fallbackStrategyConfigKey = "fallback.strategy"
+	fallbackArgsConfigKey     = "fallback.args"
+)
+
+type resolverRule struct {
+	pattern  *regexp.Regexp
+	response net.IP
+}
+
+type dnsOptions struct {
+	Rules    []resolverRule
+	Fallback ResolverFallback
+}
+
+func loadFromConfig(config *viper.Viper) dnsOptions {
+	options := dnsOptions{}
+
+	anonRules := config.Get(rulesConfigKey).([]interface{})
+	for _, rule := range anonRules {
+		innerData := rule.(map[interface{}]interface{})
+		var err error
+		var compiledPattern *regexp.Regexp
+		var response net.IP
+		if compiledPattern, err = regexp.Compile(innerData[patternConfigKey].(string)); err != nil {
+			continue
+		}
+
+		if response = net.ParseIP(innerData[responseConfigKey].(string)); response == nil {
+			continue
+		}
+
+		options.Rules = append(options.Rules, resolverRule{
+			pattern:  compiledPattern,
+			response: response,
+		})
+	}
+
+	options.Fallback = CreateResolverFallback(
+		config.GetString(fallbackStrategyConfigKey),
+		config.Sub(fallbackArgsConfigKey),
+	)
+
+	return options
+}

pkg/plugins/dns_mock/regex_handler.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"github.com/miekg/dns"
+	"go.uber.org/zap"
+)
+
+type regexHandler struct {
+	routes   []resolverRule
+	fallback ResolverFallback
+	logger   *zap.Logger
+}
+
+func (r2 *regexHandler) AddRule(rule resolverRule) {
+	r2.routes = append(r2.routes, rule)
+}
+
+func (r2 regexHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	m := new(dns.Msg)
+	m.Compress = false
+	m.SetReply(r)
+
+	switch r.Opcode {
+	case dns.OpcodeQuery:
+		r2.handleQuery(m)
+	}
+	if err := w.WriteMsg(m); err != nil {
+		r2.logger.Error(
+			"Failed to write DNS response message",
+			zap.Error(err),
+		)
+	}
+}
+
+func (r2 regexHandler) handleQuery(m *dns.Msg) {
+	for _, q := range m.Question {
+		r2.logger.Info(
+			"handling question",
+			zap.String("question", q.Name),
+		)
+		switch q.Qtype {
+		case dns.TypeA:
+			for _, rule := range r2.routes {
+				if rule.pattern.MatchString(q.Name) {
+					m.Authoritative = true
+					answer := &dns.A{
+						Hdr: dns.RR_Header{
+							Name:   q.Name,
+							Rrtype: dns.TypeA,
+							Class:  dns.ClassINET,
+							Ttl:    60,
+						},
+						A: rule.response,
+					}
+					m.Answer = append(m.Answer, answer)
+					r2.logger.Info(
+						"matched DNS rule",
+						zap.String("pattern", rule.pattern.String()),
+						zap.String("response", rule.response.String()),
+					)
+					return
+				}
+			}
+			r2.handleFallbackForMessage(m, q)
+		}
+	}
+}
+
+func (r2 regexHandler) handleFallbackForMessage(m *dns.Msg, q dns.Question) {
+	fallbackIP := r2.fallback.GetIP()
+	answer := &dns.A{
+		Hdr: dns.RR_Header{
+			Name:   q.Name,
+			Rrtype: dns.TypeA,
+			Class:  dns.ClassINET,
+			Ttl:    60,
+		},
+		A: fallbackIP,
+	}
+	r2.logger.Info(
+		"Falling back to generated IP",
+		zap.String("response", fallbackIP.String()),
+	)
+	m.Authoritative = true
+	m.Answer = append(m.Answer, answer)
+}

pkg/plugins/http_mock/Makefile

@@ -6,7 +6,7 @@ GOARGS = GOOS=linux GOARCH=amd64
 GO_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s"
 GO_CONTAINER_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s" -a -installsuffix cgo
 GO_DEBUG_BUILD_ARGS = -buildmode=plugin -gcflags "all=-N -l"
-PLUGIN_NAME = http_mock.so
+PLUGIN_NAME = $(shell basename $(DIR)).so
 OUT_DIR = $(DIR)../../../plugins
 DEBUG_PORT = 2345
 

pkg/plugins/http_mock/init.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"github.com/baez90/inetmock/internal/plugins"
+	"github.com/baez90/inetmock/pkg/api"
+	"github.com/baez90/inetmock/pkg/logging"
+	"go.uber.org/zap"
+)
+
+func init() {
+	logger, _ := logging.CreateLogger()
+	logger = logger.With(
+		zap.String("ProtocolHandler", name),
+	)
+	plugins.Registry().RegisterHandler(name, func() api.ProtocolHandler {
+		return &httpHandler{
+			logger: logger,
+			router: &RegexpHandler{},
+		}
+	})
+}

pkg/plugins/http_mock/main.go

@@ -4,9 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"github.com/baez90/inetmock/internal/config"
-	"github.com/baez90/inetmock/internal/plugins"
-	"github.com/baez90/inetmock/pkg/api"
-	"github.com/baez90/inetmock/pkg/logging"
 	"github.com/baez90/inetmock/pkg/path"
 	"go.uber.org/zap"
 	"net/http"
@@ -19,13 +16,13 @@ const (
 	name = "http_mock"
 )
 
-type httpPlugin struct {
+type httpHandler struct {
 	logger *zap.Logger
 	router *RegexpHandler
 	server *http.Server
 }
 
-func (p *httpPlugin) Run(config config.HandlerConfig) {
+func (p *httpHandler) Run(config config.HandlerConfig) {
 	options := loadFromConfig(config.Options())
 	addr := fmt.Sprintf("%s:%d", config.ListenAddress(), config.Port())
 	p.server = &http.Server{Addr: addr, Handler: p.router}
@@ -40,7 +37,7 @@ func (p *httpPlugin) Run(config config.HandlerConfig) {
 	go p.startServer()
 }
 
-func (p *httpPlugin) Shutdown(wg *sync.WaitGroup) {
+func (p *httpHandler) Shutdown(wg *sync.WaitGroup) {
 	if err := p.server.Close(); err != nil {
 		p.logger.Error(
 			"failed to shutdown HTTP server",
@@ -51,7 +48,7 @@ func (p *httpPlugin) Shutdown(wg *sync.WaitGroup) {
 	wg.Done()
 }
 
-func (p *httpPlugin) startServer() {
+func (p *httpHandler) startServer() {
 	if err := p.server.ListenAndServe(); err != nil {
 		p.logger.Error(
 			"failed to start http listener",
@@ -60,7 +57,7 @@ func (p *httpPlugin) startServer() {
 	}
 }
 
-func (p *httpPlugin) setupRoute(rule targetRule) {
+func (p *httpHandler) setupRoute(rule targetRule) {
 	var compiled *regexp.Regexp
 	var err error
 	if compiled, err = regexp.Compile(rule.pattern); err != nil {
@@ -101,16 +98,3 @@ func createHandlerForTarget(logger *zap.Logger, targetPath string) http.Handler
 		http.ServeFile(writer, request, targetFilePath)
 	})
 }
-
-func init() {
-	logger, _ := logging.CreateLogger()
-	logger = logger.With(
-		zap.String("ProtocolHandler", name),
-	)
-	plugins.Registry().RegisterHandler(name, func() api.ProtocolHandler {
-		return &httpPlugin{
-			logger: logger,
-			router: &RegexpHandler{},
-		}
-	})
-}

pkg/plugins/tls_interceptor/Makefile

@@ -6,7 +6,7 @@ GOARGS = GOOS=linux GOARCH=amd64
 GO_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s"
 GO_CONTAINER_BUILD_ARGS = -buildmode=plugin -ldflags="-w -s" -a -installsuffix cgo
 GO_DEBUG_BUILD_ARGS = -buildmode=plugin -gcflags "all=-N -l"
-PLUGIN_NAME = tls_interceptor.so
+PLUGIN_NAME = $(shell basename $(DIR)).so
 OUT_DIR = $(DIR)../../../plugins
 DEBUG_PORT = 2345