From 7761fa4b0cd6e5a0ba82fc12af639a7fc94e6884 Mon Sep 17 00:00:00 2001
From: Leopold <leopold@stumblestore.de>
Date: Fri, 25 Apr 2025 00:31:28 +0200
Subject: [PATCH] initial commit

---
 .woodpecker/build.yaml | 19 ++++++++++
 Containerfile          | 19 ++++++++++
 README.md              |  3 ++
 go.mod                 |  3 ++
 main.go                | 86 ++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 130 insertions(+)
 create mode 100644 .woodpecker/build.yaml
 create mode 100644 Containerfile
 create mode 100644 README.md
 create mode 100644 go.mod
 create mode 100644 main.go

diff --git a/.woodpecker/build.yaml b/.woodpecker/build.yaml
new file mode 100644
index 0000000..ba83203
--- /dev/null
+++ b/.woodpecker/build.yaml
@@ -0,0 +1,19 @@
+when:
+  - event: push
+    branch: main
+
+steps:
+- name: publish
+  image: woodpeckerci/plugin-kaniko
+  settings:
+    platforms: linux/amd64
+    repo: git.sakoma.wang/llamprecht/advent20xx
+    registry: git.sakoma.wang
+    tags: ${CI_COMMIT_SHA}
+    cache: true
+    username: llamprecht
+    build_args:
+    - COMMIT_SHA=${CI_COMMIT_SHA}
+    - COMMIT_AUTHOR_EMAIL=${CI_COMMIT_AUTHOR_EMAIL}
+    password:
+      from_secret: container_registry_token
diff --git a/Containerfile b/Containerfile
new file mode 100644
index 0000000..1ff8464
--- /dev/null
+++ b/Containerfile
@@ -0,0 +1,19 @@
+FROM golang:latest AS build
+
+WORKDIR /build
+
+COPY go.mod go.sum ./
+
+RUN go mod download
+
+COPY . .
+
+RUN go build -o /dynv6-update
+
+FROM scratch
+
+WORKDIR /app
+
+COPY --from=build /dynv6-update /app/dynv6-update
+
+CMD ["/app/dynv6-update"]
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..647d660
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+## dynv6-update
+
+A simple client to update the IPv6 Prefix using the dynv6 API
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..85e5c71
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.sakoma.wang/llamprecht/dynv6-update
+
+go 1.24.2
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..aaa2cd9
--- /dev/null
+++ b/main.go
@@ -0,0 +1,86 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"time"
+)
+
+type conf struct {
+	zone   string
+	token  string
+	server string
+}
+
+func main() {
+	conf, err := readConfigVars()
+	if err != nil {
+		log.Fatal(err)
+	}
+	lastIPv6 := ""
+	for {
+		time.Sleep(1 * time.Second)
+		if newIPv6, ok := checkForNewV6(lastIPv6); ok {
+			lastIPv6 = newIPv6
+			sendNewIP(conf)
+		}
+	}
+}
+
+func checkForNewV6(lastIPv6 string) (string, bool) {
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		log.Println(err)
+		return lastIPv6, false
+	}
+	currentIPv6 := ""
+	for _, inter := range interfaces {
+		addresses, err := inter.Addrs()
+		if err != nil {
+			log.Println(err)
+			return lastIPv6, false
+		}
+		for _, addr := range addresses {
+			if ip, ok := addr.(*net.IPNet); ok && !ip.IP.IsLoopback() {
+				if ip.IP.To4() == nil {
+					currentIPv6 = ip.IP.String()
+				}
+			}
+		}
+	}
+	if currentIPv6 != lastIPv6 {
+		return currentIPv6, true
+	}
+	return lastIPv6, false
+}
+
+func sendNewIP(config conf) error {
+	_, err := http.Get(fmt.Sprintf("https://ipv6.dynv6.com/api/update?ipv6prefix=auto&token=%s&zone=%s", config.token, config.zone))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func readConfigVars() (conf, error) {
+	var zone, token, server string
+	var present bool
+	if zone, present = os.LookupEnv("ZONE"); !present {
+		return conf{}, errors.New("No Zone Specified")
+	}
+	if token, present = os.LookupEnv("TOKEN"); !present {
+		return conf{}, errors.New("No Token Specified")
+	}
+	if server, present = os.LookupEnv("SERVER"); !present {
+		server = "ipv6.dynv6.com"
+	}
+	return conf{
+		zone:   zone,
+		token:  token,
+		server: server,
+	}, nil
+}