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irlap_event.c
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/*********************************************************************
*
* Filename: irlap_event.c
* Version: 0.9
* Description: IrLAP state machine implementation
* Status: Experimental.
* Author: Dag Brattli <[email protected]>
* Created at: Sat Aug 16 00:59:29 1997
* Modified at: Sat Dec 25 21:07:57 1999
* Modified by: Dag Brattli <[email protected]>
*
* Copyright (c) 1998-2000 Dag Brattli <[email protected]>,
* Copyright (c) 1998 Thomas Davis <[email protected]>
* All Rights Reserved.
* Copyright (c) 2000-2003 Jean Tourrilhes <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* Neither Dag Brattli nor University of Tromsø admit liability nor
* provide warranty for any of this software. This material is
* provided "AS-IS" and at no charge.
*
********************************************************************/
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/skbuff.h>
#include <net/irda/irda.h>
#include <net/irda/irlap_event.h>
#include <net/irda/timer.h>
#include <net/irda/irlap.h>
#include <net/irda/irlap_frame.h>
#include <net/irda/qos.h>
#include <net/irda/parameters.h>
#include <net/irda/irlmp.h> /* irlmp_flow_indication(), ... */
#include <net/irda/irda_device.h>
#ifdef CONFIG_IRDA_FAST_RR
int sysctl_fast_poll_increase = 50;
#endif
static int irlap_state_ndm (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_query (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_reply (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_conn (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_setup (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_offline(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_xmit_p (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_pclose (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_nrm_p (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_reset_wait(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_reset (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_nrm_s (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_xmit_s (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_sclose (struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info);
static int irlap_state_reset_check(struct irlap_cb *, IRLAP_EVENT event,
struct sk_buff *, struct irlap_info *);
#ifdef CONFIG_IRDA_DEBUG
static const char *irlap_event[] = {
"DISCOVERY_REQUEST",
"CONNECT_REQUEST",
"CONNECT_RESPONSE",
"DISCONNECT_REQUEST",
"DATA_REQUEST",
"RESET_REQUEST",
"RESET_RESPONSE",
"SEND_I_CMD",
"SEND_UI_FRAME",
"RECV_DISCOVERY_XID_CMD",
"RECV_DISCOVERY_XID_RSP",
"RECV_SNRM_CMD",
"RECV_TEST_CMD",
"RECV_TEST_RSP",
"RECV_UA_RSP",
"RECV_DM_RSP",
"RECV_RD_RSP",
"RECV_I_CMD",
"RECV_I_RSP",
"RECV_UI_FRAME",
"RECV_FRMR_RSP",
"RECV_RR_CMD",
"RECV_RR_RSP",
"RECV_RNR_CMD",
"RECV_RNR_RSP",
"RECV_REJ_CMD",
"RECV_REJ_RSP",
"RECV_SREJ_CMD",
"RECV_SREJ_RSP",
"RECV_DISC_CMD",
"SLOT_TIMER_EXPIRED",
"QUERY_TIMER_EXPIRED",
"FINAL_TIMER_EXPIRED",
"POLL_TIMER_EXPIRED",
"DISCOVERY_TIMER_EXPIRED",
"WD_TIMER_EXPIRED",
"BACKOFF_TIMER_EXPIRED",
"MEDIA_BUSY_TIMER_EXPIRED",
};
#endif /* CONFIG_IRDA_DEBUG */
const char *irlap_state[] = {
"LAP_NDM",
"LAP_QUERY",
"LAP_REPLY",
"LAP_CONN",
"LAP_SETUP",
"LAP_OFFLINE",
"LAP_XMIT_P",
"LAP_PCLOSE",
"LAP_NRM_P",
"LAP_RESET_WAIT",
"LAP_RESET",
"LAP_NRM_S",
"LAP_XMIT_S",
"LAP_SCLOSE",
"LAP_RESET_CHECK",
};
static int (*state[])(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info) =
{
irlap_state_ndm,
irlap_state_query,
irlap_state_reply,
irlap_state_conn,
irlap_state_setup,
irlap_state_offline,
irlap_state_xmit_p,
irlap_state_pclose,
irlap_state_nrm_p,
irlap_state_reset_wait,
irlap_state_reset,
irlap_state_nrm_s,
irlap_state_xmit_s,
irlap_state_sclose,
irlap_state_reset_check,
};
/*
* Function irda_poll_timer_expired (data)
*
* Poll timer has expired. Normally we must now send a RR frame to the
* remote device
*/
static void irlap_poll_timer_expired(void *data)
{
struct irlap_cb *self = (struct irlap_cb *) data;
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
irlap_do_event(self, POLL_TIMER_EXPIRED, NULL, NULL);
}
/*
* Calculate and set time before we will have to send back the pf bit
* to the peer. Use in primary.
* Make sure that state is XMIT_P/XMIT_S when calling this function
* (and that nobody messed up with the state). - Jean II
*/
static void irlap_start_poll_timer(struct irlap_cb *self, int timeout)
{
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
#ifdef CONFIG_IRDA_FAST_RR
/*
* Send out the RR frames faster if our own transmit queue is empty, or
* if the peer is busy. The effect is a much faster conversation
*/
if (skb_queue_empty(&self->txq) || self->remote_busy) {
if (self->fast_RR == TRUE) {
/*
* Assert that the fast poll timer has not reached the
* normal poll timer yet
*/
if (self->fast_RR_timeout < timeout) {
/*
* FIXME: this should be a more configurable
* function
*/
self->fast_RR_timeout +=
(sysctl_fast_poll_increase * HZ/1000);
/* Use this fast(er) timeout instead */
timeout = self->fast_RR_timeout;
}
} else {
self->fast_RR = TRUE;
/* Start with just 0 ms */
self->fast_RR_timeout = 0;
timeout = 0;
}
} else
self->fast_RR = FALSE;
IRDA_DEBUG(3, "%s(), timeout=%d (%ld)\n", __func__, timeout, jiffies);
#endif /* CONFIG_IRDA_FAST_RR */
if (timeout == 0)
irlap_do_event(self, POLL_TIMER_EXPIRED, NULL, NULL);
else
irda_start_timer(&self->poll_timer, timeout, self,
irlap_poll_timer_expired);
}
/*
* Function irlap_do_event (event, skb, info)
*
* Rushes through the state machine without any delay. If state == XMIT
* then send queued data frames.
*/
void irlap_do_event(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
int ret;
if (!self || self->magic != LAP_MAGIC)
return;
IRDA_DEBUG(3, "%s(), event = %s, state = %s\n", __func__,
irlap_event[event], irlap_state[self->state]);
ret = (*state[self->state])(self, event, skb, info);
/*
* Check if there are any pending events that needs to be executed
*/
switch (self->state) {
case LAP_XMIT_P: /* FALLTHROUGH */
case LAP_XMIT_S:
/*
* We just received the pf bit and are at the beginning
* of a new LAP transmit window.
* Check if there are any queued data frames, and do not
* try to disconnect link if we send any data frames, since
* that will change the state away form XMIT
*/
IRDA_DEBUG(2, "%s() : queue len = %d\n", __func__,
skb_queue_len(&self->txq));
if (!skb_queue_empty(&self->txq)) {
/* Prevent race conditions with irlap_data_request() */
self->local_busy = TRUE;
/* Theory of operation.
* We send frames up to when we fill the window or
* reach line capacity. Those frames will queue up
* in the device queue, and the driver will slowly
* send them.
* After each frame that we send, we poll the higher
* layer for more data. It's the right time to do
* that because the link layer need to perform the mtt
* and then send the first frame, so we can afford
* to send a bit of time in kernel space.
* The explicit flow indication allow to minimise
* buffers (== lower latency), to avoid higher layer
* polling via timers (== less context switches) and
* to implement a crude scheduler - Jean II */
/* Try to send away all queued data frames */
while ((skb = skb_dequeue(&self->txq)) != NULL) {
/* Send one frame */
ret = (*state[self->state])(self, SEND_I_CMD,
skb, NULL);
/* Drop reference count.
* It will be increase as needed in
* irlap_send_data_xxx() */
kfree_skb(skb);
/* Poll the higher layers for one more frame */
irlmp_flow_indication(self->notify.instance,
FLOW_START);
if (ret == -EPROTO)
break; /* Try again later! */
}
/* Finished transmitting */
self->local_busy = FALSE;
} else if (self->disconnect_pending) {
self->disconnect_pending = FALSE;
ret = (*state[self->state])(self, DISCONNECT_REQUEST,
NULL, NULL);
}
break;
/* case LAP_NDM: */
/* case LAP_CONN: */
/* case LAP_RESET_WAIT: */
/* case LAP_RESET_CHECK: */
default:
break;
}
}
/*
* Function irlap_state_ndm (event, skb, frame)
*
* NDM (Normal Disconnected Mode) state
*
*/
static int irlap_state_ndm(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
discovery_t *discovery_rsp;
int ret = 0;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
switch (event) {
case CONNECT_REQUEST:
IRDA_ASSERT(self->netdev != NULL, return -1;);
if (self->media_busy) {
/* Note : this will never happen, because we test
* media busy in irlap_connect_request() and
* postpone the event... - Jean II */
IRDA_DEBUG(0, "%s(), CONNECT_REQUEST: media busy!\n",
__func__);
/* Always switch state before calling upper layers */
irlap_next_state(self, LAP_NDM);
irlap_disconnect_indication(self, LAP_MEDIA_BUSY);
} else {
irlap_send_snrm_frame(self, &self->qos_rx);
/* Start Final-bit timer */
irlap_start_final_timer(self, self->final_timeout);
self->retry_count = 0;
irlap_next_state(self, LAP_SETUP);
}
break;
case RECV_SNRM_CMD:
/* Check if the frame contains and I field */
if (info) {
self->daddr = info->daddr;
self->caddr = info->caddr;
irlap_next_state(self, LAP_CONN);
irlap_connect_indication(self, skb);
} else {
IRDA_DEBUG(0, "%s(), SNRM frame does not "
"contain an I field!\n", __func__);
}
break;
case DISCOVERY_REQUEST:
IRDA_ASSERT(info != NULL, return -1;);
if (self->media_busy) {
IRDA_DEBUG(1, "%s(), DISCOVERY_REQUEST: media busy!\n",
__func__);
/* irlap->log.condition = MEDIA_BUSY; */
/* This will make IrLMP try again */
irlap_discovery_confirm(self, NULL);
/* Note : the discovery log is not cleaned up here,
* it will be done in irlap_discovery_request()
* Jean II */
return 0;
}
self->S = info->S;
self->s = info->s;
irlap_send_discovery_xid_frame(self, info->S, info->s, TRUE,
info->discovery);
self->frame_sent = FALSE;
self->s++;
irlap_start_slot_timer(self, self->slot_timeout);
irlap_next_state(self, LAP_QUERY);
break;
case RECV_DISCOVERY_XID_CMD:
IRDA_ASSERT(info != NULL, return -1;);
/* Assert that this is not the final slot */
if (info->s <= info->S) {
self->slot = irlap_generate_rand_time_slot(info->S,
info->s);
if (self->slot == info->s) {
discovery_rsp = irlmp_get_discovery_response();
discovery_rsp->data.daddr = info->daddr;
irlap_send_discovery_xid_frame(self, info->S,
self->slot,
FALSE,
discovery_rsp);
self->frame_sent = TRUE;
} else
self->frame_sent = FALSE;
/*
* Go to reply state until end of discovery to
* inhibit our own transmissions. Set the timer
* to not stay forever there... Jean II
*/
irlap_start_query_timer(self, info->S, info->s);
irlap_next_state(self, LAP_REPLY);
} else {
/* This is the final slot. How is it possible ?
* This would happen is both discoveries are just slightly
* offset (if they are in sync, all packets are lost).
* Most often, all the discovery requests will be received
* in QUERY state (see my comment there), except for the
* last frame that will come here.
* The big trouble when it happen is that active discovery
* doesn't happen, because nobody answer the discoveries
* frame of the other guy, so the log shows up empty.
* What should we do ?
* Not much. It's too late to answer those discovery frames,
* so we just pass the info to IrLMP who will put it in the
* log (and post an event).
* Another cause would be devices that do discovery much
* slower than us, however the latest fixes should minimise
* those cases...
* Jean II
*/
IRDA_DEBUG(1, "%s(), Receiving final discovery request, missed the discovery slots :-(\n", __func__);
/* Last discovery request -> in the log */
irlap_discovery_indication(self, info->discovery);
}
break;
case MEDIA_BUSY_TIMER_EXPIRED:
/* A bunch of events may be postponed because the media is
* busy (usually immediately after we close a connection),
* or while we are doing discovery (state query/reply).
* In all those cases, the media busy flag will be cleared
* when it's OK for us to process those postponed events.
* This event is not mentioned in the state machines in the
* IrLAP spec. It's because they didn't consider Ultra and
* postponing connection request is optional.
* Jean II */
#ifdef CONFIG_IRDA_ULTRA
/* Send any pending Ultra frames if any */
if (!skb_queue_empty(&self->txq_ultra)) {
/* We don't send the frame, just post an event.
* Also, previously this code was in timer.c...
* Jean II */
ret = (*state[self->state])(self, SEND_UI_FRAME,
NULL, NULL);
}
#endif /* CONFIG_IRDA_ULTRA */
/* Check if we should try to connect.
* This code was previously in irlap_do_event() */
if (self->connect_pending) {
self->connect_pending = FALSE;
/* This one *should* not pend in this state, except
* if a socket try to connect and immediately
* disconnect. - clear - Jean II */
if (self->disconnect_pending)
irlap_disconnect_indication(self, LAP_DISC_INDICATION);
else
ret = (*state[self->state])(self,
CONNECT_REQUEST,
NULL, NULL);
self->disconnect_pending = FALSE;
}
/* Note : one way to test if this code works well (including
* media busy and small busy) is to create a user space
* application generating an Ultra packet every 3.05 sec (or
* 2.95 sec) and to see how it interact with discovery.
* It's fairly easy to check that no packet is lost, that the
* packets are postponed during discovery and that after
* discovery indication you have a 100ms "gap".
* As connection request and Ultra are now processed the same
* way, this avoid the tedious job of trying IrLAP connection
* in all those cases...
* Jean II */
break;
#ifdef CONFIG_IRDA_ULTRA
case SEND_UI_FRAME:
{
int i;
/* Only allowed to repeat an operation twice */
for (i=0; ((i<2) && (self->media_busy == FALSE)); i++) {
skb = skb_dequeue(&self->txq_ultra);
if (skb)
irlap_send_ui_frame(self, skb, CBROADCAST,
CMD_FRAME);
else
break;
/* irlap_send_ui_frame() won't increase skb reference
* count, so no dev_kfree_skb() - Jean II */
}
if (i == 2) {
/* Force us to listen 500 ms again */
irda_device_set_media_busy(self->netdev, TRUE);
}
break;
}
case RECV_UI_FRAME:
/* Only accept broadcast frames in NDM mode */
if (info->caddr != CBROADCAST) {
IRDA_DEBUG(0, "%s(), not a broadcast frame!\n",
__func__);
} else
irlap_unitdata_indication(self, skb);
break;
#endif /* CONFIG_IRDA_ULTRA */
case RECV_TEST_CMD:
/* Remove test frame header */
skb_pull(skb, sizeof(struct test_frame));
/*
* Send response. This skb will not be sent out again, and
* will only be used to send out the same info as the cmd
*/
irlap_send_test_frame(self, CBROADCAST, info->daddr, skb);
break;
case RECV_TEST_RSP:
IRDA_DEBUG(0, "%s() not implemented!\n", __func__);
break;
default:
IRDA_DEBUG(2, "%s(), Unknown event %s\n", __func__,
irlap_event[event]);
ret = -1;
break;
}
return ret;
}
/*
* Function irlap_state_query (event, skb, info)
*
* QUERY state
*
*/
static int irlap_state_query(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
int ret = 0;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
switch (event) {
case RECV_DISCOVERY_XID_RSP:
IRDA_ASSERT(info != NULL, return -1;);
IRDA_ASSERT(info->discovery != NULL, return -1;);
IRDA_DEBUG(4, "%s(), daddr=%08x\n", __func__,
info->discovery->data.daddr);
if (!self->discovery_log) {
IRDA_WARNING("%s: discovery log is gone! "
"maybe the discovery timeout has been set"
" too short?\n", __func__);
break;
}
hashbin_insert(self->discovery_log,
(irda_queue_t *) info->discovery,
info->discovery->data.daddr, NULL);
/* Keep state */
/* irlap_next_state(self, LAP_QUERY); */
break;
case RECV_DISCOVERY_XID_CMD:
/* Yes, it is possible to receive those frames in this mode.
* Note that most often the last discovery request won't
* occur here but in NDM state (see my comment there).
* What should we do ?
* Not much. We are currently performing our own discovery,
* therefore we can't answer those frames. We don't want
* to change state either. We just pass the info to
* IrLMP who will put it in the log (and post an event).
* Jean II
*/
IRDA_ASSERT(info != NULL, return -1;);
IRDA_DEBUG(1, "%s(), Receiving discovery request (s = %d) while performing discovery :-(\n", __func__, info->s);
/* Last discovery request ? */
if (info->s == 0xff)
irlap_discovery_indication(self, info->discovery);
break;
case SLOT_TIMER_EXPIRED:
/*
* Wait a little longer if we detect an incoming frame. This
* is not mentioned in the spec, but is a good thing to do,
* since we want to work even with devices that violate the
* timing requirements.
*/
if (irda_device_is_receiving(self->netdev) && !self->add_wait) {
IRDA_DEBUG(2, "%s(), device is slow to answer, "
"waiting some more!\n", __func__);
irlap_start_slot_timer(self, msecs_to_jiffies(10));
self->add_wait = TRUE;
return ret;
}
self->add_wait = FALSE;
if (self->s < self->S) {
irlap_send_discovery_xid_frame(self, self->S,
self->s, TRUE,
self->discovery_cmd);
self->s++;
irlap_start_slot_timer(self, self->slot_timeout);
/* Keep state */
irlap_next_state(self, LAP_QUERY);
} else {
/* This is the final slot! */
irlap_send_discovery_xid_frame(self, self->S, 0xff,
TRUE,
self->discovery_cmd);
/* Always switch state before calling upper layers */
irlap_next_state(self, LAP_NDM);
/*
* We are now finished with the discovery procedure,
* so now we must return the results
*/
irlap_discovery_confirm(self, self->discovery_log);
/* IrLMP should now have taken care of the log */
self->discovery_log = NULL;
}
break;
default:
IRDA_DEBUG(2, "%s(), Unknown event %s\n", __func__,
irlap_event[event]);
ret = -1;
break;
}
return ret;
}
/*
* Function irlap_state_reply (self, event, skb, info)
*
* REPLY, we have received a XID discovery frame from a device and we
* are waiting for the right time slot to send a response XID frame
*
*/
static int irlap_state_reply(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
discovery_t *discovery_rsp;
int ret=0;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
switch (event) {
case QUERY_TIMER_EXPIRED:
IRDA_DEBUG(0, "%s(), QUERY_TIMER_EXPIRED <%ld>\n",
__func__, jiffies);
irlap_next_state(self, LAP_NDM);
break;
case RECV_DISCOVERY_XID_CMD:
IRDA_ASSERT(info != NULL, return -1;);
/* Last frame? */
if (info->s == 0xff) {
del_timer(&self->query_timer);
/* info->log.condition = REMOTE; */
/* Always switch state before calling upper layers */
irlap_next_state(self, LAP_NDM);
irlap_discovery_indication(self, info->discovery);
} else {
/* If it's our slot, send our reply */
if ((info->s >= self->slot) && (!self->frame_sent)) {
discovery_rsp = irlmp_get_discovery_response();
discovery_rsp->data.daddr = info->daddr;
irlap_send_discovery_xid_frame(self, info->S,
self->slot,
FALSE,
discovery_rsp);
self->frame_sent = TRUE;
}
/* Readjust our timer to accomodate devices
* doing faster or slower discovery than us...
* Jean II */
irlap_start_query_timer(self, info->S, info->s);
/* Keep state */
//irlap_next_state(self, LAP_REPLY);
}
break;
default:
IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __func__,
event, irlap_event[event]);
ret = -1;
break;
}
return ret;
}
/*
* Function irlap_state_conn (event, skb, info)
*
* CONN, we have received a SNRM command and is waiting for the upper
* layer to accept or refuse connection
*
*/
static int irlap_state_conn(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
int ret = 0;
IRDA_DEBUG(4, "%s(), event=%s\n", __func__, irlap_event[ event]);
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
switch (event) {
case CONNECT_RESPONSE:
skb_pull(skb, sizeof(struct snrm_frame));
IRDA_ASSERT(self->netdev != NULL, return -1;);
irlap_qos_negotiate(self, skb);
irlap_initiate_connection_state(self);
/*
* Applying the parameters now will make sure we change speed
* *after* we have sent the next frame
*/
irlap_apply_connection_parameters(self, FALSE);
/*
* Sending this frame will force a speed change after it has
* been sent (i.e. the frame will be sent at 9600).
*/
irlap_send_ua_response_frame(self, &self->qos_rx);
#if 0
/*
* We are allowed to send two frames, but this may increase
* the connect latency, so lets not do it for now.
*/
/* This is full of good intentions, but doesn't work in
* practice.
* After sending the first UA response, we switch the
* dongle to the negotiated speed, which is usually
* different than 9600 kb/s.
* From there, there is two solutions :
* 1) The other end has received the first UA response :
* it will set up the connection, move to state LAP_NRM_P,
* and will ignore and drop the second UA response.
* Actually, it's even worse : the other side will almost
* immediately send a RR that will likely collide with the
* UA response (depending on negotiated turnaround).
* 2) The other end has not received the first UA response,
* will stay at 9600 and will never see the second UA response.
* Jean II */
irlap_send_ua_response_frame(self, &self->qos_rx);
#endif
/*
* The WD-timer could be set to the duration of the P-timer
* for this case, but it is recommended to use twice the
* value (note 3 IrLAP p. 60).
*/
irlap_start_wd_timer(self, self->wd_timeout);
irlap_next_state(self, LAP_NRM_S);
break;
case RECV_DISCOVERY_XID_CMD:
IRDA_DEBUG(3, "%s(), event RECV_DISCOVER_XID_CMD!\n",
__func__);
irlap_next_state(self, LAP_NDM);
break;
case DISCONNECT_REQUEST:
IRDA_DEBUG(0, "%s(), Disconnect request!\n", __func__);
irlap_send_dm_frame(self);
irlap_next_state( self, LAP_NDM);
irlap_disconnect_indication(self, LAP_DISC_INDICATION);
break;
default:
IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __func__,
event, irlap_event[event]);
ret = -1;
break;
}
return ret;
}
/*
* Function irlap_state_setup (event, skb, frame)
*
* SETUP state, The local layer has transmitted a SNRM command frame to
* a remote peer layer and is awaiting a reply .
*
*/
static int irlap_state_setup(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
int ret = 0;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
switch (event) {
case FINAL_TIMER_EXPIRED:
if (self->retry_count < self->N3) {
/*
* Perform random backoff, Wait a random number of time units, minimum
* duration half the time taken to transmitt a SNRM frame, maximum duration
* 1.5 times the time taken to transmit a SNRM frame. So this time should
* between 15 msecs and 45 msecs.
*/
irlap_start_backoff_timer(self, msecs_to_jiffies(20 +
(jiffies % 30)));
} else {
/* Always switch state before calling upper layers */
irlap_next_state(self, LAP_NDM);
irlap_disconnect_indication(self, LAP_FOUND_NONE);
}
break;
case BACKOFF_TIMER_EXPIRED:
irlap_send_snrm_frame(self, &self->qos_rx);
irlap_start_final_timer(self, self->final_timeout);
self->retry_count++;
break;
case RECV_SNRM_CMD:
IRDA_DEBUG(4, "%s(), SNRM battle!\n", __func__);
IRDA_ASSERT(skb != NULL, return 0;);
IRDA_ASSERT(info != NULL, return 0;);
/*
* The device with the largest device address wins the battle
* (both have sent a SNRM command!)
*/
if (info &&(info->daddr > self->saddr)) {
del_timer(&self->final_timer);
irlap_initiate_connection_state(self);
IRDA_ASSERT(self->netdev != NULL, return -1;);
skb_pull(skb, sizeof(struct snrm_frame));
irlap_qos_negotiate(self, skb);
/* Send UA frame and then change link settings */
irlap_apply_connection_parameters(self, FALSE);
irlap_send_ua_response_frame(self, &self->qos_rx);
irlap_next_state(self, LAP_NRM_S);
irlap_connect_confirm(self, skb);
/*
* The WD-timer could be set to the duration of the
* P-timer for this case, but it is recommended
* to use twice the value (note 3 IrLAP p. 60).
*/
irlap_start_wd_timer(self, self->wd_timeout);
} else {
/* We just ignore the other device! */
irlap_next_state(self, LAP_SETUP);
}
break;
case RECV_UA_RSP:
/* Stop F-timer */
del_timer(&self->final_timer);
/* Initiate connection state */
irlap_initiate_connection_state(self);
/* Negotiate connection parameters */
IRDA_ASSERT(skb->len > 10, return -1;);
skb_pull(skb, sizeof(struct ua_frame));
IRDA_ASSERT(self->netdev != NULL, return -1;);
irlap_qos_negotiate(self, skb);
/* Set the new link setting *now* (before the rr frame) */
irlap_apply_connection_parameters(self, TRUE);
self->retry_count = 0;
/* Wait for turnaround time to give a chance to the other
* device to be ready to receive us.
* Note : the time to switch speed is typically larger
* than the turnaround time, but as we don't have the other
* side speed switch time, that's our best guess...
* Jean II */
irlap_wait_min_turn_around(self, &self->qos_tx);
/* This frame will actually be sent at the new speed */
irlap_send_rr_frame(self, CMD_FRAME);
/* The timer is set to half the normal timer to quickly
* detect a failure to negociate the new connection
* parameters. IrLAP 6.11.3.2, note 3.
* Note that currently we don't process this failure
* properly, as we should do a quick disconnect.
* Jean II */
irlap_start_final_timer(self, self->final_timeout/2);
irlap_next_state(self, LAP_NRM_P);
irlap_connect_confirm(self, skb);
break;
case RECV_DM_RSP: /* FALLTHROUGH */
case RECV_DISC_CMD:
del_timer(&self->final_timer);
irlap_next_state(self, LAP_NDM);
irlap_disconnect_indication(self, LAP_DISC_INDICATION);
break;
default:
IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __func__,
event, irlap_event[event]);
ret = -1;
break;
}
return ret;
}
/*
* Function irlap_state_offline (self, event, skb, info)
*
* OFFLINE state, not used for now!
*
*/
static int irlap_state_offline(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
IRDA_DEBUG( 0, "%s(), Unknown event\n", __func__);
return -1;
}
/*
* Function irlap_state_xmit_p (self, event, skb, info)
*
* XMIT, Only the primary station has right to transmit, and we
* therefore do not expect to receive any transmissions from other
* stations.
*
*/
static int irlap_state_xmit_p(struct irlap_cb *self, IRLAP_EVENT event,
struct sk_buff *skb, struct irlap_info *info)
{
int ret = 0;
switch (event) {
case SEND_I_CMD:
/*
* Only send frame if send-window > 0.
*/
if ((self->window > 0) && (!self->remote_busy)) {
int nextfit;
#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
struct sk_buff *skb_next;
/* With DYNAMIC_WINDOW, we keep the window size
* maximum, and adapt on the packets we are sending.
* At 115k, we can send only 2 packets of 2048 bytes
* in a 500 ms turnaround. Without this option, we