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

internal/configuration/sources/files/wireguardselection.go

@@ -0,0 +1,83 @@
+package files
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/netip"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/govalid/port"
+	"gopkg.in/ini.v1"
+)
+
+var (
+	ErrEndpointHostNotIP = errors.New("endpoint host is not an IP")
+)
+
+func (s *Source) readWireguardSelection() (selection settings.WireguardSelection, err error) {
+	fileStringPtr, err := ReadFromFile(s.wireguardConfigPath)
+	if err != nil {
+		return selection, fmt.Errorf("reading file: %w", err)
+	}
+
+	if fileStringPtr == nil {
+		return selection, nil
+	}
+
+	rawData := []byte(*fileStringPtr)
+	iniFile, err := ini.Load(rawData)
+	if err != nil {
+		return selection, fmt.Errorf("loading ini from reader: %w", err)
+	}
+
+	peerSection, err := iniFile.GetSection("Peer")
+	if err == nil {
+		err = parseWireguardPeerSection(peerSection, &selection)
+		if err != nil {
+			return selection, fmt.Errorf("parsing peer section: %w", err)
+		}
+	} else if !regexINISectionNotExist.MatchString(err.Error()) {
+		// can never happen
+		return selection, fmt.Errorf("getting peer section: %w", err)
+	}
+
+	return selection, nil
+}
+
+func parseWireguardPeerSection(peerSection *ini.Section,
+	selection *settings.WireguardSelection) (err error) {
+	publicKeyPtr, err := parseINIWireguardKey(peerSection, "PublicKey")
+	if err != nil {
+		return err // error is already wrapped correctly
+	} else if publicKeyPtr != nil {
+		selection.PublicKey = *publicKeyPtr
+	}
+
+	endpointKey, err := peerSection.GetKey("Endpoint")
+	if err == nil {
+		endpoint := endpointKey.String()
+		host, portString, err := net.SplitHostPort(endpoint)
+		if err != nil {
+			return fmt.Errorf("splitting endpoint: %w", err)
+		}
+
+		ip, err := netip.ParseAddr(host)
+		if err != nil {
+			return fmt.Errorf("%w: %w", ErrEndpointHostNotIP, err)
+		}
+
+		endpointPort, err := port.Validate(portString)
+		if err != nil {
+			return fmt.Errorf("port from Endpoint key: %w", err)
+		}
+
+		selection.EndpointIP = ip
+		selection.EndpointPort = &endpointPort
+	} else if !regexINIKeyNotExist.MatchString(err.Error()) {
+		// can never happen
+		return fmt.Errorf("getting endpoint key: %w", err)
+	}
+
+	return nil
+}