From 86caf454f435e3b9d740acc837d376f22a61760d Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Fri, 13 Mar 2026 22:05:12 +0000
Subject: [PATCH] refactor: share device pair ipv4 parsing

---
 extensions/device-pair/index.ts | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/extensions/device-pair/index.ts b/extensions/device-pair/index.ts
index 825d1668ac0..7ba88842a7a 100644
--- a/extensions/device-pair/index.ts
+++ b/extensions/device-pair/index.ts
@@ -108,13 +108,21 @@ function resolveScheme(
   return cfg.gateway?.tls?.enabled === true ? "wss" : "ws";
 }
 
-function isPrivateIPv4(address: string): boolean {
+function parseIPv4Octets(address: string): [number, number, number, number] | null {
   const parts = address.split(".");
-  if (parts.length != 4) {
-    return false;
+  if (parts.length !== 4) {
+    return null;
   }
   const octets = parts.map((part) => Number.parseInt(part, 10));
   if (octets.some((value) => !Number.isFinite(value) || value < 0 || value > 255)) {
+    return null;
+  }
+  return octets as [number, number, number, number];
+}
+
+function isPrivateIPv4(address: string): boolean {
+  const octets = parseIPv4Octets(address);
+  if (!octets) {
     return false;
   }
   const [a, b] = octets;
@@ -131,12 +139,8 @@ function isPrivateIPv4(address: string): boolean {
 }
 
 function isTailnetIPv4(address: string): boolean {
-  const parts = address.split(".");
-  if (parts.length !== 4) {
-    return false;
-  }
-  const octets = parts.map((part) => Number.parseInt(part, 10));
-  if (octets.some((value) => !Number.isFinite(value) || value < 0 || value > 255)) {
+  const octets = parseIPv4Octets(address);
+  if (!octets) {
     return false;
   }
   const [a, b] = octets;