14.04.2026 Update

network/overlap.go

@@ -0,0 +1,87 @@
+package network
+
+import (
+	"fmt"
+	"net"
+)
+
+type SubnetOverlap struct {
+	Interface string `json:"interface"`
+	Subnet    string `json:"subnet"`
+	Label     string `json:"label,omitempty"`
+}
+
+func parseIPNet(ipStr, maskStr string) (*net.IPNet, error) {
+	ip := net.ParseIP(ipStr)
+	if ip == nil {
+		return nil, fmt.Errorf("invalid IP: %s", ipStr)
+	}
+	ip = ip.To4()
+	if ip == nil {
+		return nil, fmt.Errorf("invalid IPv4: %s", ipStr)
+	}
+
+	mask := ipMaskFromString(maskStr)
+	if mask == nil {
+		return nil, fmt.Errorf("invalid netmask: %s", maskStr)
+	}
+
+	return &net.IPNet{IP: ip.Mask(mask), Mask: mask}, nil
+}
+
+func ipMaskFromString(maskStr string) net.IPMask {
+	m := net.ParseIP(maskStr)
+	if m != nil {
+		if m4 := m.To4(); m4 != nil {
+			return net.IPMask(m4)
+		}
+	}
+	return nil
+}
+
+func subnetsOverlap(a, b *net.IPNet) bool {
+	return a.Contains(b.IP) || b.Contains(a.IP)
+}
+
+func CheckOverlap(newIP, newMask, excludeIface string, existing []SubnetOverlap) []SubnetOverlap {
+	newNet, err := parseIPNet(newIP, newMask)
+	if err != nil {
+		return nil
+	}
+
+	var result []SubnetOverlap
+	for _, s := range existing {
+		if s.Interface == excludeIface {
+			continue
+		}
+		parts, err := parseSubnetStr(s.Subnet)
+		if err != nil {
+			continue
+		}
+		existingNet, err := parseIPNet(parts[0], parts[1])
+		if err != nil {
+			continue
+		}
+		if subnetsOverlap(newNet, existingNet) {
+			result = append(result, s)
+		}
+	}
+	return result
+}
+
+func ParseSubnet(ipStr, maskStr string) (string, error) {
+	n, err := parseIPNet(ipStr, maskStr)
+	if err != nil {
+		return "", err
+	}
+	return n.String(), nil
+}
+
+func parseSubnetStr(s string) ([2]string, error) {
+	for i := len(s) - 1; i >= 0; i-- {
+		if s[i] == '/' {
+			return [2]string{s[:i], s[i+1:]}, nil
+		}
+	}
+	return [2]string{}, fmt.Errorf("invalid subnet format: %s", s)
+}