96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
package config
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import (
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"fmt"
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"os"
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"path"
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"strings"
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)
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const (
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leaseFileKey = "dhcp-leasefile"
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rangeKey = "dhcp-range"
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confFileKey = "conf-file"
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confDirKey = "conf-dir"
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)
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func tryParseLineOption(line, key string) (string, bool) {
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if !strings.HasPrefix(line, key) {
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return "", false
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}
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_, val, found := strings.Cut(line, "=")
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return val, found
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}
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type dnsmasqConfOptions struct {
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leaseFile string
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rangeStart string
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rangeEnd string
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}
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func defaultDNSMasqOptions() map[string]string {
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return map[string]string{
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confDirKey: "/etc/dnsmasq.d",
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confFileKey: "",
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leaseFileKey: "/var/lib/misc/dnsmasq.leases",
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rangeKey: "",
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}
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}
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func parseDNSMasqConfFile(content string, options map[string]string) {
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for _, l := range strings.Split(content, "\n") {
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for key := range options {
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newVal, found := tryParseLineOption(l, key)
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if found {
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options[key] = newVal
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}
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}
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}
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}
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func parseDNSMasqOptions(rootFileContent string) (dnsmasqConfOptions, error) {
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rawOptions := defaultDNSMasqOptions()
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// start with parsing the root file
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parseDNSMasqConfFile(rootFileContent, rawOptions)
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// get all additional conf files in the provided directory
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confDir := rawOptions[confDirKey]
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if confDir != "" {
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entries, err := os.ReadDir(confDir)
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if err != nil {
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return dnsmasqConfOptions{}, fmt.Errorf("failed to get list of additional config files: %w", err)
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}
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for _, e := range entries {
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if e.IsDir() || !strings.HasSuffix(e.Name(), ".conf") {
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continue
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}
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fileContent, err := os.ReadFile(path.Join(confDir, e.Name()))
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if err != nil {
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return dnsmasqConfOptions{}, fmt.Errorf("failed to read sub config file: %w", err)
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}
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parseDNSMasqConfFile(string(fileContent), rawOptions)
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}
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}
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// get any additional config file
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if additionalFile := rawOptions[confFileKey]; additionalFile != "" {
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filecontent, err := os.ReadFile(additionalFile)
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if err != nil {
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return dnsmasqConfOptions{}, fmt.Errorf("failed to read additional config file: %w", err)
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}
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parseDNSMasqConfFile(string(filecontent), rawOptions)
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}
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dhcpRange := strings.Split(rawOptions[rangeKey], ",")
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if len(dhcpRange) < 2 {
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return dnsmasqConfOptions{}, fmt.Errorf("invalid value for DHCP range: %s", rawOptions[rangeKey])
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}
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return dnsmasqConfOptions{
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leaseFile: rawOptions[leaseFileKey],
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rangeStart: dhcpRange[0],
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rangeEnd: dhcpRange[1],
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}, nil
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}
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