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internal/clouddetect/loader.go

@@ -0,0 +1,50 @@
+package clouddetect
+
+import (
+	"bufio"
+	"net"
+	"os"
+	"strings"
+)
+
+// LoadCIDRs reads the cloud_ranges.txt file and parses the CIDR blocks for each provider.
+// The file format is simple: a provider name followed by a colon, then one CIDR per line.
+// Blank lines and lines starting with '#' are ignored.
+func LoadCIDRs(filePath string) (map[string][]*net.IPNet, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	cidrs := make(map[string][]*net.IPNet)
+	var currentProvider string
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		// Provider header, e.g., "Cloudflare:"
+		if strings.HasSuffix(line, ":") {
+			currentProvider = strings.TrimSuffix(line, ":")
+			continue
+		}
+		// CIDR entry
+		if currentProvider == "" {
+			// Skip CIDR without a provider header.
+			continue
+		}
+		_, ipnet, err := net.ParseCIDR(line)
+		if err != nil {
+			// Invalid CIDR – skip it.
+			continue
+		}
+		cidrs[currentProvider] = append(cidrs[currentProvider], ipnet)
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+	return cidrs, nil
+}