feat(settings): parse Wireguard settings from /gluetun/wireguard/wg0.conf (#1120)

internal/configuration/sources/files/wireguard.go

@@ -0,0 +1,111 @@
+package files
+
+import (
+	"fmt"
+	"net/netip"
+	"regexp"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+	"gopkg.in/ini.v1"
+)
+
+var (
+	regexINISectionNotExist = regexp.MustCompile(`^section ".+" does not exist$`)
+	regexINIKeyNotExist     = regexp.MustCompile(`key ".*" not exists$`)
+)
+
+func (s *Source) readWireguard() (wireguard settings.Wireguard, err error) {
+	fileStringPtr, err := ReadFromFile(s.wireguardConfigPath)
+	if err != nil {
+		return wireguard, fmt.Errorf("reading file: %w", err)
+	}
+
+	if fileStringPtr == nil {
+		return wireguard, nil
+	}
+
+	rawData := []byte(*fileStringPtr)
+	iniFile, err := ini.Load(rawData)
+	if err != nil {
+		return wireguard, fmt.Errorf("loading ini from reader: %w", err)
+	}
+
+	interfaceSection, err := iniFile.GetSection("Interface")
+	if err == nil {
+		err = parseWireguardInterfaceSection(interfaceSection, &wireguard)
+		if err != nil {
+			return wireguard, fmt.Errorf("parsing interface section: %w", err)
+		}
+	} else if !regexINISectionNotExist.MatchString(err.Error()) {
+		// can never happen
+		return wireguard, fmt.Errorf("getting interface section: %w", err)
+	}
+
+	return wireguard, nil
+}
+
+func parseWireguardInterfaceSection(interfaceSection *ini.Section,
+	wireguard *settings.Wireguard) (err error) {
+	wireguard.PrivateKey, err = parseINIWireguardKey(interfaceSection, "PrivateKey")
+	if err != nil {
+		return err // error is already wrapped correctly
+	}
+
+	wireguard.PreSharedKey, err = parseINIWireguardKey(interfaceSection, "PreSharedKey")
+	if err != nil {
+		return err // error is already wrapped correctly
+	}
+
+	wireguard.Addresses, err = parseINIWireguardAddress(interfaceSection)
+	if err != nil {
+		return err // error is already wrapped correctly
+	}
+
+	return nil
+}
+
+func parseINIWireguardKey(section *ini.Section, keyName string) (
+	key *string, err error) {
+	iniKey, err := section.GetKey(keyName)
+	if err != nil {
+		if regexINIKeyNotExist.MatchString(err.Error()) {
+			return nil, nil //nolint:nilnil
+		}
+		// can never happen
+		return nil, fmt.Errorf("getting %s key: %w", keyName, err)
+	}
+
+	key = new(string)
+	*key = iniKey.String()
+	_, err = wgtypes.ParseKey(*key)
+	if err != nil {
+		return nil, fmt.Errorf("parsing %s: %s: %w", keyName, *key, err)
+	}
+	return key, nil
+}
+
+func parseINIWireguardAddress(section *ini.Section) (
+	addresses []netip.Prefix, err error) {
+	addressKey, err := section.GetKey("Address")
+	if err != nil {
+		if regexINIKeyNotExist.MatchString(err.Error()) {
+			return nil, nil
+		}
+		// can never happen
+		return nil, fmt.Errorf("getting Address key: %w", err)
+	}
+
+	addressStrings := strings.Split(addressKey.String(), ",")
+	addresses = make([]netip.Prefix, len(addressStrings))
+	for i, addressString := range addressStrings {
+		addressString = strings.TrimSpace(addressString)
+		addresses[i], err = netip.ParsePrefix(addressString)
+		if err != nil {
+			return nil, fmt.Errorf("parsing address: %w", err)
+		}
+	}
+
+	return addresses, nil
+}