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|
package imap
import (
"crypto/tls"
"fmt"
"net"
"time"
"git.sr.ht/~rjarry/aerc/lib"
"git.sr.ht/~rjarry/aerc/logging"
"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 = logging.ErrorLogger()
if w.config.user != nil {
username := w.config.user.Username()
// TODO: 2nd parameter false if no password is set. ask for it
// if unset.
password, _ := w.config.user.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
}
}
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) {
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 {
logging.Errorf("cannot set tcp keepalive probes: %v", err)
}
// Wait time after an unsuccessful probe
err = lib.SetTcpKeepaliveInterval(fd, w.config.keepalive_interval)
if err != nil {
logging.Errorf("cannot set tcp keepalive interval: %v", err)
}
})
return err
}
|
