Adding support for DNS response IP sustitute

.gitignore

@@ -0,0 +1 @@
+_output/

Makefile

@@ -0,0 +1,37 @@
+# ==============================================================================
+# 定义全局 Makefile 变量方便后面引用
+PROJ_NAME = dnsproxy
+
+COMMON_SELF_DIR := $(dir $(lastword $(MAKEFILE_LIST)))
+# 项目根目录
+ROOT_DIR := $(abspath $(shell cd $(COMMON_SELF_DIR)/ && pwd -P))
+# 构建产物、临时文件存放目录
+OUTPUT_DIR := $(ROOT_DIR)/_output
+
+# ==============================================================================
+# 定义 Makefile all 伪目标，执行 `make` 时，会默认会执行 all 伪目标
+.PHONY: all
+all: add-copyright format build
+
+# ==============================================================================
+# 定义其他需要的伪目标
+
+.PHONY: build
+build: tidy # 编译源码，依赖 tidy 目标自动添加/移除依赖包.
+	@go build -v -o $(OUTPUT_DIR)/${PROJ_NAME} $(ROOT_DIR)/dnsproxy.go
+
+.PHONY: format
+format: # 格式化 Go 源码.
+	@gofmt -s -w ./
+
+.PHONY: tidy
+tidy: # 自动添加/移除依赖包.
+	@go mod tidy
+
+.PHONY: clean
+clean: # 清理构建产物、临时文件等.
+	@-rm -vrf $(OUTPUT_DIR)
+
+.PHONY: run
+run:
+	sudo $(OUTPUT_DIR)/${PROJ_NAME}

README-en.md

@@ -0,0 +1,55 @@
+## Proxy DNS query use TCP in go lang
+
+苦于本地DNS污染，连github.com这种都经常解析不了。最近愈发频繁，所以写了这个程序。
+
+- 采用多个dns地址轮询。
+- dns 请求时，默认 read/write 都为 100ms 超时，实测已经足够，更长时间会导致网页访问变慢。
+- 使用 TCP 做 DNS 解析，转发正常的 UDP 请求。
+- go-cache 做缓存，默认一小时失效，pure go，无需安装其它组件。
+
+另有使用 redis 做缓存的版本在 redis-cache 分支
+
+Dependencies：
+
+    go get github.com/miekg/dns
+    go get github.com/pmylund/go-cache
+
+跨平台编译后放到了我的 arm 开发板 pcDuino 上，现在又可以作为 DNS服务器 了 ^_^  
+Build for special platform:
+
+    GOOS=linux GOARCH=arm go build src/dnsproxy.go
+
+数台电脑，移动设备，平稳运行两天，正常解析。
+
+## Using
+
+Supported arguments, all these could use as commandline flags like `-xxx=xxx`：
+
+	dnss   = flag.String("dns", "192.168.2.1:53,8.8.8.8:53,8.8.4.4:53", "dns address, use `,` as sep")
+	local  = flag.String("local", ":53", "local listen address")
+	debug  = flag.Int("debug", 0, "debug level 0 1 2")
+	cache  = flag.Bool("cache", true, "enable go-cache")
+	expire = flag.Int64("expire", 3600, "default cache expire time")
+	ipv6   = flag.Bool("6", false, "skip ipv6 record query AAAA")
+	hostfile = flag.String("hostfile", "_output/host-file.txt, "host file for dns result intercept & substitute")
+
+`make build` to build the executable file: `dnsproxy`
+
+> [New Feature] To replace DNS response results using rules defined in the hostfile, you need to manually place the edited hostfile into the _output directory.
+
+`make run` to run
+
+Run manually：
+
+    sudo ./dnsproxy
+
+Set dns address，using `,` as the delimiter.
+
+    sudo ./dnsproxy -dns=x.x.x.x:53,x.x.x.x:53
+
+Using `-debug` flag could print the dns query log.
+
+    sudo ./dnsproxy -debug=1
+
+### Thanks
+Part of source code from [HERE](https://gist.github.com/mrluanma/3722792)

README.md

@@ -1,4 +1,4 @@
-##Proxy DNS query use TCP in go lang
+## Proxy DNS query use TCP in go lang
 
 苦于本地DNS污染，连github.com这种都经常解析不了。最近愈发频繁，所以写了这个程序。
 
@@ -20,7 +20,7 @@
 
 数台电脑，移动设备，平稳运行两天，正常解析。
 
-##使用方法
+## 使用方法
 
 支持的参数：
 
@@ -30,9 +30,15 @@
 	cache  = flag.Bool("cache", true, "enable go-cache")
 	expire = flag.Int64("expire", 3600, "default cache expire time")
 	ipv6   = flag.Bool("6", false, "skip ipv6 record query AAAA")
+	hostfile = flag.String("hostfile", "_output/host-file.txt, "host file for dns result intercept & substitute")
 
-build 生成 dnsproxy 文件后
-执行：
+`make build` 生成 dnsproxy 文件后  
+
+> 如要使用hostfile内规则替换DNS响应结果，需手动将编辑好的hostfile文件放入`_output`目录下  
+
+`make run`运行
+
+手动执行：
 
     sudo ./dnsproxy
 
@@ -44,5 +50,5 @@ build 生成 dnsproxy 文件后
 
     sudo ./dnsproxy -debug=1
 
-###Thanks
+### Thanks
 部分代码源自 [这里](https://gist.github.com/mrluanma/3722792)

dnsproxy.go

@@ -2,11 +2,10 @@ package main
 
 import (
 	"crypto/md5"
+	"dnsproxy/regex"
 	"encoding/hex"
 	"flag"
 	"fmt"
-	"github.com/miekg/dns"
-	"github.com/pmylund/go-cache"
 	"log"
 	"net"
 	"os"
@@ -17,17 +16,21 @@ import (
 	"strings"
 	"syscall"
 	"time"
+
+	"github.com/miekg/dns"
+	"github.com/pmylund/go-cache"
 )
 
 var (
-	dnss    = flag.String("dns", "192.168.2.1:53:udp,8.8.8.8:53:udp,8.8.4.4:53:udp,8.8.8.8:53:tcp,8.8.4.4:53:tcp", "dns address, use `,` as sep")
-	local   = flag.String("local", ":53", "local listen address")
-	debug   = flag.Int("debug", 0, "debug level 0 1 2")
-	encache = flag.Bool("cache", true, "enable go-cache")
-	expire  = flag.Int64("expire", 3600, "default cache expire seconds, -1 means use doamin ttl time")
-	file    = flag.String("file", filepath.Join(path.Dir(os.Args[0]), "cache.dat"), "cached file")
-	ipv6    = flag.Bool("6", false, "skip ipv6 record query AAAA")
-	timeout = flag.Int("timeout", 200, "read/write timeout")
+	dnss     = flag.String("dns", "127.0.0.53:53:udp,127.0.0.53:53:tcp", "dns address, use `,` as sep")
+	local    = flag.String("local", "127.0.0.1:53", "local listen address")
+	debug    = flag.Int("debug", 0, "debug level 0 1 2")
+	encache  = flag.Bool("cache", true, "enable go-cache")
+	expire   = flag.Int64("expire", 3600, "default cache expire seconds, -1 means use doamin ttl time")
+	file     = flag.String("file", filepath.Join(path.Dir(os.Args[0]), "cache.dat"), "cached file")
+	ipv6     = flag.Bool("6", false, "skip ipv6 record query AAAA")
+	timeout  = flag.Int("timeout", 200, "read/write timeout")
+	hostfile = flag.String("hostfile", filepath.Join(path.Dir(os.Args[0]), "host-file.txt"), "hosts with wildcard")
 
 	clientTCP *dns.Client
 	clientUDP *dns.Client
@@ -125,6 +128,8 @@ func init() {
 		log.Fatalln("dns address must be not empty")
 	}
 
+	regex.Init(*hostfile)
+
 	signal.Notify(saveSig, syscall.SIGINT, syscall.SIGHUP, syscall.SIGTERM, syscall.SIGQUIT)
 }
 
@@ -157,7 +162,14 @@ func proxyServe(w dns.ResponseWriter, req *dns.Msg) {
 		query     []string
 		questions []dns.Question
 		used      string
+		reqName   string
 	)
+	if len(req.Question) > 0 {
+		for _, v := range req.Question {
+			// log.Printf("%s\t,Recv:%s", v.Name, v.String())
+			reqName = v.Name
+		}
+	}
 
 	defer func() {
 		if err := recover(); err != nil {
@@ -192,6 +204,13 @@ func proxyServe(w dns.ResponseWriter, req *dns.Msg) {
 
 	if ENCACHE {
 		if reply, ok := conn.Get(key); ok {
+			if DEBUG > 1 {
+				if ok {
+					log.Printf("Cache find [%s]", questions[0].Name)
+				} else {
+					log.Printf("Cache MISS [%s]", questions[0].Name)
+				}
+			}
 			data, _ = reply.([]byte)
 		}
 		if data != nil && len(data) > 0 {
@@ -234,6 +253,8 @@ func proxyServe(w dns.ResponseWriter, req *dns.Msg) {
 		}
 	}
 
+	substituteResponse(reqName, m)
+
 	if err == nil {
 		if DEBUG > 0 {
 			if tried {
@@ -260,12 +281,17 @@ func proxyServe(w dns.ResponseWriter, req *dns.Msg) {
 						}
 					}
 					conn.Set(key, data, time.Second*time.Duration(ttl))
+					// log.Printf("Cache Set [%s]", questions[0].Name)
 					m.Id = id
 					if DEBUG > 0 {
 						log.Printf("id: %5d cache: CACHED %v TTL %v\n", id, query, ttl)
 					}
 				}
+			} else {
+				log.Printf("Response write fail [%s]", questions[0].Name)
 			}
+		} else {
+			log.Printf("Response pack fail [%s]", questions[0].Name)
 		}
 	}
 
@@ -284,3 +310,32 @@ end:
 		fmt.Println("====================================================")
 	}
 }
+
+func substituteResponse(reqName string, m *dns.Msg) error {
+	if regex.MappingTree == nil || len(reqName) < 1 {
+		return nil
+	}
+	defer func() {
+		if err := recover(); err != nil {
+			log.Fatalln(err)
+		}
+	}()
+	// log.Printf("Begin replace [%s]", reqName)
+	// Check if the last character is a period
+	reqName = strings.TrimSuffix(reqName, ".")
+
+	ip := regex.MappingTree.FindReverse(reqName)
+	if ip == "" {
+		// log.Printf(" --- Replace not Found [%s]", reqName)
+		return nil
+	}
+	log.Printf("Do replace [%s] with IP [%s]", reqName, ip)
+	newResponse, err := dns.NewRR(reqName + " 3600 IN A " + ip)
+	if err != nil {
+		log.Printf(" --- Replace ERROR [%s]", reqName)
+		return err
+	}
+	m.Answer = make([]dns.RR, 1)
+	m.Answer[0] = newResponse
+	return nil
+}

go.mod

@@ -0,0 +1,15 @@
+module dnsproxy
+
+go 1.21.4
+
+require (
+	github.com/miekg/dns v1.1.57
+	github.com/pmylund/go-cache v2.1.0+incompatible
+)
+
+require (
+	golang.org/x/mod v0.12.0 // indirect
+	golang.org/x/net v0.17.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/tools v0.13.0 // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/miekg/dns v1.1.57 h1:Jzi7ApEIzwEPLHWRcafCN9LZSBbqQpxjt/wpgvg7wcM=
+github.com/miekg/dns v1.1.57/go.mod h1:uqRjCRUuEAA6qsOiJvDd+CFo/vW+y5WR6SNmHE55hZk=
+github.com/pmylund/go-cache v2.1.0+incompatible h1:n+7K51jLz6a3sCvff3BppuCAkixuDHuJ/C57Vw/XjTE=
+github.com/pmylund/go-cache v2.1.0+incompatible/go.mod h1:hmz95dGvINpbRZGsqPcd7B5xXY5+EKb5PpGhQY3NTHk=
+golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
+golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
+golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/tools v0.13.0 h1:Iey4qkscZuv0VvIt8E0neZjtPVQFSc870HQ448QgEmQ=
+golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=