From cfc0d34a584254a9ed76620951c810771aff6f3b Mon Sep 17 00:00:00 2001
From: Alexander Hunt <me@liz.coffee>
Date: Sun, 21 Jun 2026 12:43:31 -0700
Subject: STUFF

---
 utils/net.go | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'utils')

diff --git a/utils/net.go b/utils/net.go
index 76454bd..c69d90f 100644
--- a/utils/net.go
+++ b/utils/net.go
@@ -16,6 +16,13 @@ func (m *Mac) Format() string {
 		m.Addr[0], m.Addr[1], m.Addr[2], m.Addr[3], m.Addr[4], m.Addr[5])
 }
 
+// Compact renders the MAC as 12 lowercase hex digits with no separators, the
+// form used as a DNS label (e.g. aabbccddeeff).
+func (m *Mac) Compact() string {
+	return fmt.Sprintf("%02x%02x%02x%02x%02x%02x",
+		m.Addr[0], m.Addr[1], m.Addr[2], m.Addr[3], m.Addr[4], m.Addr[5])
+}
+
 // ParseMac reads a colon-separated hex MAC. It tolerates uppercase and the
 // zero-stripped octets macOS prints (e.g. "8:0:27:ab:cd:ef").
 func ParseMac(s string) (*Mac, error) {
@@ -32,6 +39,25 @@ func ParseMac(s string) (*Mac, error) {
 	return mac, nil
 }
 
+// ParseMacCompact reads the 12-hex-digit, separator-less form used as a DNS
+// label (e.g. aabbccddeeff) back into a Mac.
+func ParseMacCompact(s string) (*Mac, error) {
+	mac := &Mac{}
+	t := strings.TrimSpace(s)
+	if len(t) != 12 {
+		return nil, fmt.Errorf("invalid compact mac %q: want 12 hex digits, got %d", s, len(t))
+	}
+	n, err := fmt.Sscanf(t, "%2x%2x%2x%2x%2x%2x",
+		&mac.Addr[0], &mac.Addr[1], &mac.Addr[2], &mac.Addr[3], &mac.Addr[4], &mac.Addr[5])
+	if err != nil {
+		return nil, err
+	}
+	if n != 6 {
+		return nil, fmt.Errorf("invalid compact mac %q: parsed %d of 6 octets", s, n)
+	}
+	return mac, nil
+}
+
 // INet4 is an IPv4 address.
 type INet4 struct {
 	Addr [4]byte
-- 
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