/
utils.go
executable file
·273 lines (234 loc) · 8.04 KB
/
utils.go
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/*
* Copyright (c) 2015, Psiphon Inc.
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package psiphon
import (
"crypto/x509"
"encoding/base64"
std_errors "errors"
"fmt"
"net"
"os"
"runtime"
"runtime/debug"
"syscall"
"time"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/crypto/ssh"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/errors"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/quic"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/refraction"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/resolver"
"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/stacktrace"
)
// MakePsiphonUserAgent constructs a User-Agent value to use for web service
// requests made by the tunnel-core client. The User-Agent includes useful stats
// information; it is to be used only for HTTPS requests, where the header
// cannot be seen by an adversary.
func MakePsiphonUserAgent(config *Config) string {
userAgent := "psiphon-tunnel-core"
if config.ClientVersion != "" {
userAgent += fmt.Sprintf("/%s", config.ClientVersion)
}
if config.ClientPlatform != "" {
userAgent += fmt.Sprintf(" (%s)", config.ClientPlatform)
}
return userAgent
}
func DecodeCertificate(encodedCertificate string) (certificate *x509.Certificate, err error) {
derEncodedCertificate, err := base64.StdEncoding.DecodeString(encodedCertificate)
if err != nil {
return nil, errors.Trace(err)
}
certificate, err = x509.ParseCertificate(derEncodedCertificate)
if err != nil {
return nil, errors.Trace(err)
}
return certificate, nil
}
// TrimError removes the middle of over-long error message strings
func TrimError(err error) error {
const MAX_LEN = 100
message := fmt.Sprintf("%s", err)
if len(message) > MAX_LEN {
return std_errors.New(message[:MAX_LEN/2] + "..." + message[len(message)-MAX_LEN/2:])
}
return err
}
// IsAddressInUseError returns true when the err is due to EADDRINUSE/WSAEADDRINUSE.
func IsAddressInUseError(err error) bool {
if err, ok := err.(*net.OpError); ok {
if err, ok := err.Err.(*os.SyscallError); ok {
if err.Err == syscall.EADDRINUSE {
return true
}
// Special case for Windows, WSAEADDRINUSE (10048). In the case
// where the socket already bound to the port has set
// SO_EXCLUSIVEADDRUSE, the error will instead be WSAEACCES (10013).
if errno, ok := err.Err.(syscall.Errno); ok {
if int(errno) == 10048 || int(errno) == 10013 {
return true
}
}
}
}
return false
}
// SyncFileWriter wraps a file and exposes an io.Writer. At predefined
// steps, the file is synced (flushed to disk) while writing.
type SyncFileWriter struct {
file *os.File
step int
count int
}
// NewSyncFileWriter creates a SyncFileWriter.
func NewSyncFileWriter(file *os.File) *SyncFileWriter {
return &SyncFileWriter{
file: file,
step: 2 << 16,
count: 0}
}
// Write implements io.Writer with periodic file syncing.
func (writer *SyncFileWriter) Write(p []byte) (n int, err error) {
n, err = writer.file.Write(p)
if err != nil {
return
}
writer.count += n
if writer.count >= writer.step {
err = writer.file.Sync()
writer.count = 0
}
return
}
// emptyAddr implements the net.Addr interface. emptyAddr is intended to be
// used as a stub, when a net.Addr is required but not used.
type emptyAddr struct {
}
func (e *emptyAddr) String() string {
return ""
}
func (e *emptyAddr) Network() string {
return ""
}
// channelConn implements the net.Conn interface. channelConn allows use of
// SSH.Channels in contexts where a net.Conn is expected. Only Read/Write/Close
// are implemented and the remaining functions are stubs and expected to not
// be used.
type channelConn struct {
ssh.Channel
}
func newChannelConn(channel ssh.Channel) *channelConn {
return &channelConn{
Channel: channel,
}
}
func (conn *channelConn) LocalAddr() net.Addr {
return new(emptyAddr)
}
func (conn *channelConn) RemoteAddr() net.Addr {
return new(emptyAddr)
}
func (conn *channelConn) SetDeadline(_ time.Time) error {
return errors.TraceNew("unsupported")
}
func (conn *channelConn) SetReadDeadline(_ time.Time) error {
return errors.TraceNew("unsupported")
}
func (conn *channelConn) SetWriteDeadline(_ time.Time) error {
return errors.TraceNew("unsupported")
}
func emitMemoryMetrics() {
var memStats runtime.MemStats
runtime.ReadMemStats(&memStats)
NoticeInfo("Memory metrics at %s: goroutines %d | objects %d | alloc %s | inuse %s | sys %s | cumulative %d %s",
stacktrace.GetParentFunctionName(),
runtime.NumGoroutine(),
memStats.HeapObjects,
common.FormatByteCount(memStats.HeapAlloc),
common.FormatByteCount(memStats.HeapInuse+memStats.StackInuse+memStats.MSpanInuse+memStats.MCacheInuse),
common.FormatByteCount(memStats.Sys),
memStats.Mallocs,
common.FormatByteCount(memStats.TotalAlloc))
}
func emitDatastoreMetrics() {
NoticeInfo("Datastore metrics at %s: %s", stacktrace.GetParentFunctionName(), GetDataStoreMetrics())
}
func emitDNSMetrics(resolver *resolver.Resolver) {
NoticeInfo("DNS metrics at %s: %s", stacktrace.GetParentFunctionName(), resolver.GetMetrics())
}
func DoGarbageCollection() {
debug.SetGCPercent(5)
debug.FreeOSMemory()
}
// conditionallyEnabledComponents implements the
// protocol.ConditionallyEnabledComponents interface.
type conditionallyEnabledComponents struct {
}
func (c conditionallyEnabledComponents) QUICEnabled() bool {
return quic.Enabled()
}
func (c conditionallyEnabledComponents) RefractionNetworkingEnabled() bool {
return refraction.Enabled()
}
// FileMigration represents the action of moving a file, or directory, to a new
// location.
type FileMigration struct {
// Name is the name of the migration for logging because file paths are not
// logged as they may contain sensitive information.
Name string
// OldPath is the current location of the file.
OldPath string
// NewPath is the location that the file should be moved to.
NewPath string
// IsDir should be set to true if the file is a directory.
IsDir bool
}
// DoFileMigration performs the specified file move operation. An error will be
// returned and the operation will not performed if: a file is expected, but a
// directory is found; a directory is expected, but a file is found; or a file,
// or directory, already exists at the target path of the move operation.
// Note: an attempt is made to redact any file paths from the returned error.
func DoFileMigration(migration FileMigration) error {
// Prefix string added to any errors for debug purposes.
errPrefix := ""
if len(migration.Name) > 0 {
errPrefix = fmt.Sprintf("(%s) ", migration.Name)
}
if !common.FileExists(migration.OldPath) {
return errors.TraceNew(errPrefix + "old path does not exist")
}
info, err := os.Stat(migration.OldPath)
if err != nil {
return errors.Tracef(errPrefix+"error getting file info: %s", common.RedactFilePathsError(err, migration.OldPath))
}
if info.IsDir() != migration.IsDir {
if migration.IsDir {
return errors.TraceNew(errPrefix + "expected directory but found file")
}
return errors.TraceNew(errPrefix + "expected but found directory")
}
if common.FileExists(migration.NewPath) {
return errors.TraceNew(errPrefix + "file already exists, will not overwrite")
}
err = os.Rename(migration.OldPath, migration.NewPath)
if err != nil {
return errors.Tracef(errPrefix+"renaming file failed with error %s", common.RedactFilePathsError(err, migration.OldPath, migration.NewPath))
}
return nil
}