initial simple dns with block

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1758262103,
+        "narHash": "sha256-aBGl3XEOsjWw6W3AHiKibN7FeoG73dutQQEqnd/etR8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "12bd230118a1901a4a5d393f9f56b6ad7e571d01",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,29 @@
+{
+  description = "System";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
+  };
+
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      {
+        devShells = {
+          default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              go
+              gopls
+              codex
+            ];
+          };
+        };
+      }
+    );
+}

go.mod

@@ -0,0 +1,13 @@
+module git.yadunut.dev/yadunut/nutdns
+
+go 1.25.0
+
+require github.com/miekg/dns v1.1.68
+
+require (
+	golang.org/x/mod v0.24.0 // indirect
+	golang.org/x/net v0.40.0 // indirect
+	golang.org/x/sync v0.14.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+	golang.org/x/tools v0.33.0 // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/miekg/dns v1.1.68 h1:jsSRkNozw7G/mnmXULynzMNIsgY2dHC8LO6U6Ij2JEA=
+github.com/miekg/dns v1.1.68/go.mod h1:fujopn7TB3Pu3JM69XaawiU0wqjpL9/8xGop5UrTPps=
+golang.org/x/mod v0.24.0 h1:ZfthKaKaT4NrhGVZHO1/WDTwGES4De8KtWO0SIbNJMU=
+golang.org/x/mod v0.24.0/go.mod h1:IXM97Txy2VM4PJ3gI61r1YEk/gAj6zAHN3AdZt6S9Ww=
+golang.org/x/net v0.40.0 h1:79Xs7wF06Gbdcg4kdCCIQArK11Z1hr5POQ6+fIYHNuY=
+golang.org/x/net v0.40.0/go.mod h1:y0hY0exeL2Pku80/zKK7tpntoX23cqL3Oa6njdgRtds=
+golang.org/x/sync v0.14.0 h1:woo0S4Yywslg6hp4eUFjTVOyKt0RookbpAHG4c1HmhQ=
+golang.org/x/sync v0.14.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
+golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
+golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/tools v0.33.0 h1:4qz2S3zmRxbGIhDIAgjxvFutSvH5EfnsYrRBj0UI0bc=
+golang.org/x/tools v0.33.0/go.mod h1:CIJMaWEY88juyUfo7UbgPqbC8rU2OqfAV1h2Qp0oMYI=

main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"log"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+const upstream = "1.1.1.1:53"
+
+var blocklist = map[string]bool{
+	"x.com.": true,
+}
+
+func handleDNS(w dns.ResponseWriter, r *dns.Msg) {
+	m := new(dns.Msg)
+	m.SetReply(r)
+
+	c := new(dns.Client)
+	for _, q := range r.Question {
+		log.Printf("question: %s", q.Name)
+		if blocklist[strings.ToLower(q.Name)] {
+			res, err := dns.NewRR(q.Name + " 60 IN A 0.0.0.0")
+			if err != nil {
+				log.Fatal(err)
+			}
+			m.Answer = append(m.Answer, res)
+		} else {
+			req := new(dns.Msg)
+			req.Question = append(req.Question, q)
+			res, _, err := c.Exchange(req, upstream)
+			if err != nil {
+				log.Fatal(err)
+			}
+			m.Answer = append(m.Answer, res.Answer...)
+
+		}
+	}
+	w.WriteMsg(m)
+}
+
+func main() {
+
+	dns.HandleFunc(".", handleDNS)
+
+	server := &dns.Server{Addr: ":8053", Net: "udp"}
+	log.Println("Starting DNS Server on :53")
+	log.Fatal(server.ListenAndServe())
+}