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-rw-r--r--worker/imap/connect.go178
1 files changed, 178 insertions, 0 deletions
diff --git a/worker/imap/connect.go b/worker/imap/connect.go
new file mode 100644
index 00000000..9cc394b4
--- /dev/null
+++ b/worker/imap/connect.go
@@ -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
+}