imap: add timeout to tcp connect functions

Extract the tcp connection details and timeout the tcp connect functions
(net.ResolveTCPAddr and net.DialTCP). If timed out, ensure that the
connection is properly closed.

Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>
This commit is contained in:
Koni Marti 2022-04-30 01:08:58 +02:00 committed by Robin Jarry
parent b92efe4cd9
commit b29293d7b5
2 changed files with 188 additions and 120 deletions

178
worker/imap/connect.go Normal file
View file

@ -0,0 +1,178 @@
package imap
import (
"crypto/tls"
"fmt"
"net"
"time"
"git.sr.ht/~rjarry/aerc/lib"
"github.com/emersion/go-imap"
"github.com/emersion/go-imap/client"
)
// connect establishes a new tcp connection to the imap server, logs in and
// selects the default inbox. If no error is returned, the imap client will be
// in the imap.SelectedState.
func (w *IMAPWorker) connect() (*client.Client, error) {
var (
conn *net.TCPConn
err error
c *client.Client
)
conn, err = newTCPConn(w.config.addr, w.config.connection_timeout)
if conn == nil || err != nil {
return nil, err
}
if w.config.connection_timeout > 0 {
end := time.Now().Add(w.config.connection_timeout)
err = conn.SetDeadline(end)
if err != nil {
return nil, err
}
}
if w.config.keepalive_period > 0 {
err = w.setKeepaliveParameters(conn)
if err != nil {
return nil, err
}
}
serverName, _, _ := net.SplitHostPort(w.config.addr)
tlsConfig := &tls.Config{ServerName: serverName}
switch w.config.scheme {
case "imap":
c, err = client.New(conn)
if err != nil {
return nil, err
}
if !w.config.insecure {
if err = c.StartTLS(tlsConfig); err != nil {
return nil, err
}
}
case "imaps":
tlsConn := tls.Client(conn, tlsConfig)
c, err = client.New(tlsConn)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("Unknown IMAP scheme %s", w.config.scheme)
}
c.ErrorLog = w.worker.Logger
if w.config.user != nil {
username := w.config.user.Username()
password, hasPassword := w.config.user.Password()
if !hasPassword {
// TODO: ask password
}
if w.config.oauthBearer.Enabled {
if err := w.config.oauthBearer.Authenticate(
username, password, c); err != nil {
return nil, err
}
} else if err := c.Login(username, password); err != nil {
return nil, err
}
}
c.SetDebug(w.worker.Logger.Writer())
if _, err := c.Select(imap.InboxName, false); err != nil {
return nil, err
}
return c, nil
}
// newTCPConn establishes a new tcp connection. Timeout will ensure that the
// function does not hang when there is no connection. If there is a timeout,
// but a valid connection is eventually returned, ensure that it is properly
// closed.
func newTCPConn(addr string, timeout time.Duration) (*net.TCPConn, error) {
var errTCPTimeout = fmt.Errorf("tcp connection timeout")
type tcpConn struct {
conn *net.TCPConn
err error
}
done := make(chan tcpConn)
go func() {
addr, err := net.ResolveTCPAddr("tcp", addr)
if err != nil {
done <- tcpConn{nil, err}
return
}
newConn, err := net.DialTCP("tcp", nil, addr)
if err != nil {
done <- tcpConn{nil, err}
return
}
done <- tcpConn{newConn, nil}
return
}()
select {
case <-time.After(timeout):
go func() {
if tcpResult := <-done; tcpResult.conn != nil {
tcpResult.conn.Close()
}
}()
return nil, errTCPTimeout
case tcpResult := <-done:
if tcpResult.conn == nil || tcpResult.err != nil {
return nil, tcpResult.err
}
return tcpResult.conn, nil
}
}
// Set additional keepalive parameters.
// Uses new interfaces introduced in Go1.11, which let us get connection's file
// descriptor, without blocking, and therefore without uncontrolled spawning of
// threads (not goroutines, actual threads).
func (w *IMAPWorker) setKeepaliveParameters(conn *net.TCPConn) error {
err := conn.SetKeepAlive(true)
if err != nil {
return err
}
// Idle time before sending a keepalive probe
err = conn.SetKeepAlivePeriod(w.config.keepalive_period)
if err != nil {
return err
}
rawConn, e := conn.SyscallConn()
if e != nil {
return e
}
err = rawConn.Control(func(fdPtr uintptr) {
fd := int(fdPtr)
// Max number of probes before failure
err := lib.SetTcpKeepaliveProbes(fd, w.config.keepalive_probes)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive probes: %v\n", err)
}
// Wait time after an unsuccessful probe
err = lib.SetTcpKeepaliveInterval(fd, w.config.keepalive_interval)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive interval: %v\n", err)
}
})
return err
}

View file

@ -1,9 +1,7 @@
package imap
import (
"crypto/tls"
"fmt"
"net"
"net/url"
"time"
@ -25,6 +23,7 @@ func init() {
var (
errUnsupported = fmt.Errorf("unsupported command")
errClientNotReady = fmt.Errorf("client not ready")
errNotConnected = fmt.Errorf("not connected")
errAlreadyConnected = fmt.Errorf("already connected")
)
@ -93,6 +92,15 @@ func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
var reterr error // will be returned at the end, needed to support idle
// when client is nil allow only certain messages to be handled
if w.client == nil {
switch msg.(type) {
case *types.Connect, *types.Reconnect, *types.Disconnect, *types.Configure:
default:
return errClientNotReady
}
}
// set connection timeout for calls to imap server
if w.client != nil {
w.client.Timeout = w.config.connection_timeout
@ -251,124 +259,6 @@ func (w *IMAPWorker) handleImapUpdate(update client.Update) {
}
}
func (w *IMAPWorker) connect() (*client.Client, error) {
var (
conn *net.TCPConn
c *client.Client
)
addr, err := net.ResolveTCPAddr("tcp", w.config.addr)
if err != nil {
return nil, err
}
conn, err = net.DialTCP("tcp", nil, addr)
if err != nil {
return nil, err
}
if w.config.connection_timeout > 0 {
end := time.Now().Add(w.config.connection_timeout)
err = conn.SetDeadline(end)
if err != nil {
return nil, err
}
}
if w.config.keepalive_period > 0 {
err = w.setKeepaliveParameters(conn)
if err != nil {
return nil, err
}
}
serverName, _, _ := net.SplitHostPort(w.config.addr)
tlsConfig := &tls.Config{ServerName: serverName}
switch w.config.scheme {
case "imap":
c, err = client.New(conn)
if err != nil {
return nil, err
}
if !w.config.insecure {
if err = c.StartTLS(tlsConfig); err != nil {
return nil, err
}
}
case "imaps":
tlsConn := tls.Client(conn, tlsConfig)
c, err = client.New(tlsConn)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("Unknown IMAP scheme %s", w.config.scheme)
}
c.ErrorLog = w.worker.Logger
if w.config.user != nil {
username := w.config.user.Username()
password, hasPassword := w.config.user.Password()
if !hasPassword {
// TODO: ask password
}
if w.config.oauthBearer.Enabled {
if err := w.config.oauthBearer.Authenticate(
username, password, c); err != nil {
return nil, err
}
} else if err := c.Login(username, password); err != nil {
return nil, err
}
}
c.SetDebug(w.worker.Logger.Writer())
if _, err := c.Select(imap.InboxName, false); err != nil {
return nil, err
}
return c, nil
}
// Set additional keepalive parameters.
// Uses new interfaces introduced in Go1.11, which let us get connection's file
// descriptor, without blocking, and therefore without uncontrolled spawning of
// threads (not goroutines, actual threads).
func (w *IMAPWorker) setKeepaliveParameters(conn *net.TCPConn) error {
err := conn.SetKeepAlive(true)
if err != nil {
return err
}
// Idle time before sending a keepalive probe
err = conn.SetKeepAlivePeriod(w.config.keepalive_period)
if err != nil {
return err
}
rawConn, e := conn.SyscallConn()
if e != nil {
return e
}
err = rawConn.Control(func(fdPtr uintptr) {
fd := int(fdPtr)
// Max number of probes before failure
err := lib.SetTcpKeepaliveProbes(fd, w.config.keepalive_probes)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive probes: %v\n", err)
}
// Wait time after an unsuccessful probe
err = lib.SetTcpKeepaliveInterval(fd, w.config.keepalive_interval)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive interval: %v\n", err)
}
})
return err
}
func (w *IMAPWorker) Run() {
for {
select {