@@ -25,6 +25,8 @@ Config Initiator
#. Switch the serial line to using the n_gsm line discipline by using
``TIOCSETD`` ioctl.
+#. Configure the mux using ``GSMIOC_GETCONF_EXT``/``GSMIOC_SETCONF_EXT`` ioctl if needed.
+
#. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl.
#. Obtain base gsmtty number for the used serial port.
@@ -42,6 +44,7 @@ Config Initiator
int ldisc = N_GSM0710;
struct gsm_config c;
+ struct gsm_config_ext ce;
struct termios configuration;
uint32_t first;
@@ -62,6 +65,12 @@ Config Initiator
/* use n_gsm line discipline */
ioctl(fd, TIOCSETD, &ldisc);
+ /* get n_gsm extended configuration */
+ ioctl(fd, GSMIOC_GETCONF_EXT, &ce);
+ /* use keep-alive once every 5s for modem connection supervision */
+ ce.keep_alive = 500;
+ /* set the new extended configuration */
+ ioctl(fd, GSMIOC_SETCONF_EXT, &ce);
/* get n_gsm configuration */
ioctl(fd, GSMIOC_GETCONF, &c);
/* we are initiator and need encoding 0 (basic) */
@@ -106,6 +115,9 @@ Config Requester
#. Switch the serial line to using the *n_gsm* line discipline by using
``TIOCSETD`` ioctl.
+#. Configure the mux using ``GSMIOC_GETCONF_EXT``/``GSMIOC_SETCONF_EXT``
+ ioctl if needed.
+
#. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl.
#. Obtain base gsmtty number for the used serial port::
@@ -119,6 +131,7 @@ Config Requester
int ldisc = N_GSM0710;
struct gsm_config c;
+ struct gsm_config_ext ce;
struct termios configuration;
uint32_t first;
@@ -132,6 +145,12 @@ Config Requester
/* use n_gsm line discipline */
ioctl(fd, TIOCSETD, &ldisc);
+ /* get n_gsm extended configuration */
+ ioctl(fd, GSMIOC_GETCONF_EXT, &ce);
+ /* use keep-alive once every 5s for peer connection supervision */
+ ce.keep_alive = 500;
+ /* set the new extended configuration */
+ ioctl(fd, GSMIOC_SETCONF_EXT, &ce);
/* get n_gsm configuration */
ioctl(fd, GSMIOC_GETCONF, &c);
/* we are requester and need encoding 0 (basic) */
@@ -318,6 +318,11 @@ struct gsm_mux {
struct gsm_control *pending_cmd;/* Our current pending command */
spinlock_t control_lock; /* Protects the pending command */
+ /* Keep-alive */
+ struct timer_list ka_timer; /* Keep-alive response timer */
+ u8 ka_num; /* Keep-alive match pattern */
+ signed int ka_retries; /* Keep-alive retry counter, -1 if not yet initialized */
+
/* Configuration */
int adaption; /* 1 or 2 supported */
u8 ftype; /* UI or UIH */
@@ -325,6 +330,7 @@ struct gsm_mux {
unsigned int t3; /* Power wake-up timer in seconds. */
int n2; /* Retry count */
u8 k; /* Window size */
+ u32 keep_alive; /* Control channel keep-alive in 10ms */
/* Statistics (not currently exposed) */
unsigned long bad_fcs;
@@ -1903,11 +1909,13 @@ static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
const u8 *data, int clen)
{
struct gsm_control *ctrl;
+ struct gsm_dlci *dlci;
unsigned long flags;
spin_lock_irqsave(&gsm->control_lock, flags);
ctrl = gsm->pending_cmd;
+ dlci = gsm->dlci[0];
command |= 1;
/* Does the reply match our command */
if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
@@ -1922,6 +1930,53 @@ static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
/* Or did we receive the PN response to our PN command */
} else if (command == CMD_PN) {
gsm_control_negotiation(gsm, 0, data, clen);
+ /* Or did we receive the TEST response to our TEST command */
+ } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) {
+ gsm->ka_retries = -1; /* trigger new keep-alive message */
+ if (dlci && !dlci->dead)
+ mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100);
+ }
+ spin_unlock_irqrestore(&gsm->control_lock, flags);
+}
+
+/**
+ * gsm_control_keep_alive - check timeout or start keep-alive
+ * @t: timer contained in our gsm object
+ *
+ * Called off the keep-alive timer expiry signaling that our link
+ * partner is not responding anymore. Link will be closed.
+ * This is also called to startup our timer.
+ */
+
+static void gsm_control_keep_alive(struct timer_list *t)
+{
+ struct gsm_mux *gsm = from_timer(gsm, t, ka_timer);
+ unsigned long flags;
+
+ spin_lock_irqsave(&gsm->control_lock, flags);
+ if (gsm->ka_num && gsm->ka_retries == 0) {
+ /* Keep-alive expired -> close the link */
+ if (debug & DBG_ERRORS)
+ pr_debug("%s keep-alive timed out\n", __func__);
+ spin_unlock_irqrestore(&gsm->control_lock, flags);
+ if (gsm->dlci[0])
+ gsm_dlci_begin_close(gsm->dlci[0]);
+ return;
+ } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) {
+ if (gsm->ka_retries > 0) {
+ /* T2 expired for keep-alive -> resend */
+ gsm->ka_retries--;
+ } else {
+ /* Start keep-alive timer */
+ gsm->ka_num++;
+ if (!gsm->ka_num)
+ gsm->ka_num++;
+ gsm->ka_retries = (signed int)gsm->n2;
+ }
+ gsm_control_command(gsm, CMD_TEST, &gsm->ka_num,
+ sizeof(gsm->ka_num));
+ mod_timer(&gsm->ka_timer,
+ jiffies + gsm->t2 * HZ / 100);
}
spin_unlock_irqrestore(&gsm->control_lock, flags);
}
@@ -2067,8 +2122,10 @@ static void gsm_dlci_close(struct gsm_dlci *dlci)
/* Ensure that gsmtty_open() can return. */
tty_port_set_initialized(&dlci->port, false);
wake_up_interruptible(&dlci->port.open_wait);
- } else
+ } else {
+ del_timer(&dlci->gsm->ka_timer);
dlci->gsm->dead = true;
+ }
/* A DLCI 0 close is a MUX termination so we need to kick that
back to userspace somehow */
gsm_dlci_data_kick(dlci);
@@ -2084,6 +2141,8 @@ static void gsm_dlci_close(struct gsm_dlci *dlci)
static void gsm_dlci_open(struct gsm_dlci *dlci)
{
+ struct gsm_mux *gsm = dlci->gsm;
+
/* Note that SABM UA .. SABM UA first UA lost can mean that we go
open -> open */
del_timer(&dlci->t1);
@@ -2093,8 +2152,15 @@ static void gsm_dlci_open(struct gsm_dlci *dlci)
if (debug & DBG_ERRORS)
pr_debug("DLCI %d goes open.\n", dlci->addr);
/* Send current modem state */
- if (dlci->addr)
+ if (dlci->addr) {
gsm_modem_update(dlci, 0);
+ } else {
+ /* Start keep-alive control */
+ gsm->ka_num = 0;
+ gsm->ka_retries = -1;
+ mod_timer(&gsm->ka_timer,
+ jiffies + gsm->keep_alive * HZ / 100);
+ }
gsm_dlci_data_kick(dlci);
wake_up(&dlci->gsm->event);
}
@@ -2847,6 +2913,7 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
/* Finish outstanding timers, making sure they are done */
del_timer_sync(&gsm->kick_timer);
del_timer_sync(&gsm->t2_timer);
+ del_timer_sync(&gsm->ka_timer);
/* Finish writing to ldisc */
flush_work(&gsm->tx_work);
@@ -2994,6 +3061,7 @@ static struct gsm_mux *gsm_alloc_mux(void)
INIT_LIST_HEAD(&gsm->tx_data_list);
timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
+ timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0);
INIT_WORK(&gsm->tx_work, gsmld_write_task);
init_waitqueue_head(&gsm->event);
spin_lock_init(&gsm->control_lock);
@@ -3010,6 +3078,7 @@ static struct gsm_mux *gsm_alloc_mux(void)
gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
gsm->mtu = 64;
gsm->dead = true; /* Avoid early tty opens */
+ gsm->keep_alive = 0; /* Disabled */
/* Store the instance to the mux array or abort if no space is
* available.
@@ -3145,6 +3214,29 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
return 0;
}
+static void gsm_copy_config_ext_values(struct gsm_mux *gsm,
+ struct gsm_config_ext *ce)
+{
+ memset(ce, 0, sizeof(*ce));
+ ce->keep_alive = gsm->keep_alive;
+}
+
+static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce)
+{
+ unsigned int i;
+
+ /*
+ * Check that userspace doesn't put stuff in here to prevent breakages
+ * in the future.
+ */
+ for (i = 0; i < ARRAY_SIZE(ce->reserved); i++)
+ if (ce->reserved[i])
+ return -EINVAL;
+
+ gsm->keep_alive = ce->keep_alive;
+ return 0;
+}
+
/**
* gsmld_output - write to link
* @gsm: our mux
@@ -3463,6 +3555,7 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
unsigned long arg)
{
struct gsm_config c;
+ struct gsm_config_ext ce;
struct gsm_mux *gsm = tty->disc_data;
unsigned int base;
@@ -3479,6 +3572,15 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
case GSMIOC_GETFIRST:
base = mux_num_to_base(gsm);
return put_user(base + 1, (__u32 __user *)arg);
+ case GSMIOC_GETCONF_EXT:
+ gsm_copy_config_ext_values(gsm, &ce);
+ if (copy_to_user((void __user *)arg, &ce, sizeof(ce)))
+ return -EFAULT;
+ return 0;
+ case GSMIOC_SETCONF_EXT:
+ if (copy_from_user(&ce, (void __user *)arg, sizeof(ce)))
+ return -EFAULT;
+ return gsm_config_ext(gsm, &ce);
default:
return n_tty_ioctl_helper(tty, cmd, arg);
}
@@ -39,4 +39,14 @@ struct gsm_netconfig {
/* get the base tty number for a configured gsmmux tty */
#define GSMIOC_GETFIRST _IOR('G', 4, __u32)
+struct gsm_config_ext {
+ __u32 keep_alive; /* Control channel keep-alive in 1/100th of a
+ * second (0 to disable)
+ */
+ __u32 reserved[7]; /* For future use, must be initialized to zero */
+};
+
+#define GSMIOC_GETCONF_EXT _IOR('G', 5, struct gsm_config_ext)
+#define GSMIOC_SETCONF_EXT _IOW('G', 6, struct gsm_config_ext)
+
#endif