document dnsd for others

4 files changed, 112 insertions, 19 deletions

diff --git a/cmd/dnsd/Dockerfile b/cmd/dnsd/Dockerfile
new file mode 100644
index 0000000..7cd22bf
--- /dev/null
+++ b/cmd/dnsd/Dockerfile
@@ -0,0 +1,11 @@
+ARG X_VERSION
+
+FROM xena/xperimental:$X_VERSION as build
+FROM xena/alpine
+
+ENV PORT 53
+ENV FORWARD_SERVER 1.1.1.1:53
+EXPOSE 53/udp
+
+COPY --from=build /usr/local/bin/dnsd /usr/local/bin/dnsd
+CMD /usr/local/bin/dnsd
diff --git a/cmd/dnsd/README.md b/cmd/dnsd/README.md
new file mode 100644
index 0000000..2855ae3
--- /dev/null
+++ b/cmd/dnsd/README.md
@@ -0,0 +1,87 @@
+# dnsd
+
+A custom DNS server for my network. DNS zone files are dynamically downloaded on
+startup and are continuously monitored for changes. When the DNS zone is changed,
+the service reloads it.
+
+I primarily use this to give myself a limited form of piHole DNS adblocking, as
+well as serving my [home network services](https://home.cetacean.club).
+
+This is related to my [WireGuard Site to Site VPN](https://christine.website/blog/site-to-site-wireguard-part-1-2019-04-02)
+project.
+
+## How to Configure `dnsd`
+
+`dnsd` relies on [RFC 1035](https://tools.ietf.org/html/rfc1035) zone files. This
+is a file that looks roughly like this:
+
+```rfc1035
+$TTL 60
+$ORIGIN pele.
+@       IN     SOA     oho.pele. some@email.address. (
+                       2019040601  ; serial number YYYYMMDDNN
+                       28800       ; Refresh
+                       7200        ; Retry
+                       864000      ; Expire
+                       60          ; Minimum DNS TTL
+                       )
+        IN     NS      oho.pele.
+        
+oho IN A 10.55.0.1
+1.0.55.10.in-addr.arpa. IN PTR oho.pele.
+
+;; apps
+prometheus IN CNAME oho.pele.
+grafana IN CNAME oho.pele.
+```
+
+Put this file in a publicly available place and then set its URL as a
+`-zone-file` in the command line configuration. This file will be monitored
+every minute for changes (via the proxy of the ETag of the HTTP responses).
+
+If you need to change the DNS forwarding server, set the value of the environment
+variable `FORWARD_SERVER` or the command line flag `-forward-server`.
+
+## Installation
+
+### Docker
+
+```console
+$ docker run --name dnsd -p 53:53/udp -dit --restart always xena/dnsd:1.0.2-5-g64aea8a \
+  dnsd -zone-url https://domain.hostname.tld/path/to/your.zone \
+       -zone-url https://domain.hostname.tld/path/to/adblock.zone \
+       -forward-server 1.1.1.1:53
+```
+
+### From Git with systemd
+
+```console
+$ go get -u -v github.com/Xe/x/cmd/dnsd@latest
+$ GOBIN=$(pwd) go install github.com/Xe/x/cmd/dnsd
+$ sudo cp dnsd /usr/local/bin/dnsd
+<edit dnsd.service as needed>
+$ sudo cp dnsd.service /etc/systemd/system/dnsd.service
+$ sudo systemctl daemon-reload
+$ sudo systemctl start dnsd
+$ sudo systemctl status dnsd
+$ sudo systemctl enable dnsd
+```
+
+## Testing
+
+```console
+$ dig @127.0.0.1 google.com
+$ dig @127.0.0.1 custom.domain
+```
+
+## Support
+
+If you need help with this, please [contact](https://christine.website/contact) me.
+This is fairly simplistic software. If you need anything more, I'd suggest using
+[CoreDNS](https://coredns.io) or similar.
+
+If you like this software, please consider donating on [Patreon](https://www.patreon.com/cadey)
+or [Ko-Fi](https://www.ko-fi.com/christinedodrill). I use this software daily on my personal
+network to service most of my devices.
+
+Thanks and be well.
diff --git a/cmd/dnsd/dnsd.service b/cmd/dnsd/dnsd.service
new file mode 100644
index 0000000..73add3d
--- /dev/null
+++ b/cmd/dnsd/dnsd.service
@@ -0,0 +1,12 @@
+[Unit]
+Description=dnsd
+
+[Service]
+Environment=PORT=53
+Environment=FORWARD_SERVER=1.1.1.1:53
+ExecStart=/usr/local/bin/dnsd -zone-file https://host.domain.tld/path/to/your.zone -zone-file https://host.domain.tld/path/to/adblock.zone
+Restart=always
+RestartSec=1s
+
+[Install]
+WantedBy=multi-user.target
diff --git a/cmd/dnsd/main.go b/cmd/dnsd/main.go
index 6e25be8..eefa518 100644
--- a/cmd/dnsd/main.go
+++ b/cmd/dnsd/main.go
@@ -6,11 +6,10 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"time"
 	"os/signal"
 	"syscall"
+	"time"
 
-	"go.chromium.org/luci/common/flag/stringmapflag"
 	"github.com/Xe/x/internal"
 	"github.com/miekg/dns"
 	"github.com/mmikulicic/stringlist"
@@ -20,8 +19,6 @@ var (
 	port   = flag.String("port", "53", "UDP port to listen on for DNS")
 	server = flag.String("forward-server", "1.1.1.1:53", "forward DNS server")
 
-	prefixes = new(stringmapflag.Value)
-
 	zoneURLs = stringlist.Flag("zone-url", "DNS zonefiles to load")
 )
 
@@ -30,10 +27,6 @@ var (
 		"https://xena.greedo.xeserv.us/files/akua.zone",
 		"https://xena.greedo.xeserv.us/files/adblock.zone",
 	}
-
-	defaultPrefixes = map[string]string {
-		"eq": "10.88.0.1:53",
-	}
 )
 
 func monitorURLs(urls []string) {
@@ -44,7 +37,7 @@ func monitorURLs(urls []string) {
 
 	for {
 		select {
-		case <- t.C:
+		case <-t.C:
 			for _, urli := range urls {
 				resp, err := http.Get(urli)
 				if err != nil {
@@ -67,18 +60,8 @@ func monitorURLs(urls []string) {
 }
 
 func main() {
-	flag.Var(prefixes, "prefix", "sets prefix=host:port to forward DNS requests to")
 	internal.HandleStartup()
 
-	if len(*prefixes) == 0 {
-		v := stringmapflag.Value(defaultPrefixes)
-		prefixes = &v
-	}
-
-	for k, v := range *prefixes {
-		log.Printf("conf: -prefix %s=%s", k, v)
-	}
-
 	if len(*zoneURLs) == 0 {
 		*zoneURLs = defaultZoneURLS
 	}