mainloop: Add OC_CMD_PAUSE operation

This forces the connection to immediately drop, and
openconnect_mainloop() to return with status 1.  The caller may
re-invoke the mainloop when he wants to re-establish the connection,
assuming the idle/session timeouts have not expired.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>

cstp.c

@@ -569,6 +569,8 @@ int cstp_reconnect(struct openconnect_info *vpninfo)
 		poll_cmd_fd(vpninfo, interval);
 		if (vpninfo->got_cancel_cmd)
 			return -EINTR;
+		if (vpninfo->got_pause_cmd)
+			return 0;
 		timeout -= interval;
 		interval += vpninfo->reconnect_interval;
 		if (interval > RECONNECT_INTERVAL_MAX)
@@ -709,6 +711,9 @@ int cstp_mainloop(struct openconnect_info *vpninfo, int *timeout)
 	int len, ret;
 	int work_done = 0;
 
+	if (vpninfo->ssl_fd == -1)
+		goto do_reconnect;
+
 	/* FIXME: The poll() handling here is fairly simplistic. Actually,
 	   if the SSL connection stalls it could return a WANT_WRITE error
 	   on _either_ of the SSL_read() or SSL_write() calls. In that case,

mainloop.c

@@ -55,6 +55,7 @@ int queue_new_packet(struct pkt **q, void *buf, int len)
 }
 
 /* Return value:
+ *  = 0, when successfully paused (may call again)
  *  = -EINTR, if aborted locally via cmd_fd
  *  = -EPIPE, if the remote end explicitly terminated the session
  *  = -EPERM, if the gateway sent 401 Unauthorized (cookie expired)
@@ -86,7 +87,8 @@ int openconnect_mainloop(struct openconnect_info *vpninfo,
 			dtls_try_handshake(vpninfo);
 
 		if (vpninfo->dtls_attempt_period && !vpninfo->dtls_ssl && !vpninfo->new_dtls_ssl &&
-		    vpninfo->new_dtls_started + vpninfo->dtls_attempt_period < time(NULL)) {
+		    vpninfo->new_dtls_started + vpninfo->dtls_attempt_period < time(NULL) &&
+		    vpninfo->ssl_fd != -1) {
 			vpn_progress(vpninfo, PRG_TRACE, _("Attempt new DTLS connection\n"));
 			connect_dtls_socket(vpninfo);
 		}
@@ -115,6 +117,17 @@ int openconnect_mainloop(struct openconnect_info *vpninfo,
 			ret = -EINTR;
 			break;
 		}
+		if (vpninfo->got_pause_cmd) {
+			/* close all connections and wait for the user to call
+			   openconnect_mainloop() again */
+			openconnect_close_https(vpninfo, 0);
+			dtls_close(vpninfo, 1);
+			vpninfo->new_dtls_started = 0;
+
+			vpninfo->got_pause_cmd = 0;
+			vpn_progress(vpninfo, PRG_INFO, _("Caller paused the connection\n"));
+			return 0;
+		}
 
 		if (did_work)
 			continue;

openconnect-internal.h

@@ -299,6 +299,7 @@ struct openconnect_info {
 	int cmd_fd;
 	int cmd_fd_write;
 	int got_cancel_cmd;
+	int got_pause_cmd;
 
 	struct pkt *incoming_queue;
 	struct pkt *outgoing_queue;

openconnect.h

@@ -168,7 +168,8 @@ struct oc_auth_form {
 #define PRG_TRACE	3
 
 /* byte commands to write into the cmd_fd */
-#define OC_CMD_CANCEL	'x'
+#define OC_CMD_CANCEL		'x'
+#define OC_CMD_PAUSE		'p'
 
 #define RECONNECT_INTERVAL_MIN	10
 #define RECONNECT_INTERVAL_MAX	100

ssl.c

@@ -549,6 +549,9 @@ void check_cmd_fd(struct openconnect_info *vpninfo, fd_set *fds)
 	case OC_CMD_CANCEL:
 		vpninfo->got_cancel_cmd = 1;
 		break;
+	case OC_CMD_PAUSE:
+		vpninfo->got_pause_cmd = 1;
+		break;
 	}
 }