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linux/net/irda/irlmp_frame.c

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/*********************************************************************
*
* Filename: irlmp_frame.c
* Version: 0.9
* Description: IrLMP frame implementation
* Status: Experimental.
* Author: Dag Brattli <dagb@cs.uit.no>
* Created at: Tue Aug 19 02:09:59 1997
* Modified at: Mon Dec 13 13:41:12 1999
* Modified by: Dag Brattli <dagb@cs.uit.no>
*
* Copyright (c) 1998-1999 Dag Brattli <dagb@cs.uit.no>
* All Rights Reserved.
* Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
*
* 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/skbuff.h>
#include <linux/kernel.h>
#include <net/irda/irda.h>
#include <net/irda/irlap.h>
#include <net/irda/timer.h>
#include <net/irda/irlmp.h>
#include <net/irda/irlmp_frame.h>
#include <net/irda/discovery.h>
static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap,
__u8 slsap, int status, hashbin_t *);
inline void irlmp_send_data_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
int expedited, struct sk_buff *skb)
{
skb->data[0] = dlsap;
skb->data[1] = slsap;
if (expedited) {
IRDA_DEBUG(4, "%s(), sending expedited data\n", __func__);
irlap_data_request(self->irlap, skb, TRUE);
} else
irlap_data_request(self->irlap, skb, FALSE);
}
/*
* Function irlmp_send_lcf_pdu (dlsap, slsap, opcode,skb)
*
* Send Link Control Frame to IrLAP
*/
void irlmp_send_lcf_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
__u8 opcode, struct sk_buff *skb)
{
__u8 *frame;
IRDA_DEBUG(2, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
IRDA_ASSERT(skb != NULL, return;);
frame = skb->data;
frame[0] = dlsap | CONTROL_BIT;
frame[1] = slsap;
frame[2] = opcode;
if (opcode == DISCONNECT)
frame[3] = 0x01; /* Service user request */
else
frame[3] = 0x00; /* rsvd */
irlap_data_request(self->irlap, skb, FALSE);
}
/*
* Function irlmp_input (skb)
*
* Used by IrLAP to pass received data frames to IrLMP layer
*
*/
void irlmp_link_data_indication(struct lap_cb *self, struct sk_buff *skb,
int unreliable)
{
struct lsap_cb *lsap;
__u8 slsap_sel; /* Source (this) LSAP address */
__u8 dlsap_sel; /* Destination LSAP address */
__u8 *fp;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
IRDA_ASSERT(skb->len > 2, return;);
fp = skb->data;
/*
* The next statements may be confusing, but we do this so that
* destination LSAP of received frame is source LSAP in our view
*/
slsap_sel = fp[0] & LSAP_MASK;
dlsap_sel = fp[1];
/*
* Check if this is an incoming connection, since we must deal with
* it in a different way than other established connections.
*/
if ((fp[0] & CONTROL_BIT) && (fp[2] == CONNECT_CMD)) {
IRDA_DEBUG(3, "%s(), incoming connection, "
"source LSAP=%d, dest LSAP=%d\n",
__func__, slsap_sel, dlsap_sel);
/* Try to find LSAP among the unconnected LSAPs */
lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, CONNECT_CMD,
irlmp->unconnected_lsaps);
/* Maybe LSAP was already connected, so try one more time */
if (!lsap) {
IRDA_DEBUG(1, "%s(), incoming connection for LSAP already connected\n", __func__);
lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
self->lsaps);
}
} else
lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
self->lsaps);
if (lsap == NULL) {
IRDA_DEBUG(2, "IrLMP, Sorry, no LSAP for received frame!\n");
IRDA_DEBUG(2, "%s(), slsap_sel = %02x, dlsap_sel = %02x\n",
__func__, slsap_sel, dlsap_sel);
if (fp[0] & CONTROL_BIT) {
IRDA_DEBUG(2, "%s(), received control frame %02x\n",
__func__, fp[2]);
} else {
IRDA_DEBUG(2, "%s(), received data frame\n", __func__);
}
return;
}
/*
* Check if we received a control frame?
*/
if (fp[0] & CONTROL_BIT) {
switch (fp[2]) {
case CONNECT_CMD:
lsap->lap = self;
irlmp_do_lsap_event(lsap, LM_CONNECT_INDICATION, skb);
break;
case CONNECT_CNF:
irlmp_do_lsap_event(lsap, LM_CONNECT_CONFIRM, skb);
break;
case DISCONNECT:
IRDA_DEBUG(4, "%s(), Disconnect indication!\n",
__func__);
irlmp_do_lsap_event(lsap, LM_DISCONNECT_INDICATION,
skb);
break;
case ACCESSMODE_CMD:
IRDA_DEBUG(0, "Access mode cmd not implemented!\n");
break;
case ACCESSMODE_CNF:
IRDA_DEBUG(0, "Access mode cnf not implemented!\n");
break;
default:
IRDA_DEBUG(0, "%s(), Unknown control frame %02x\n",
__func__, fp[2]);
break;
}
} else if (unreliable) {
/* Optimize and bypass the state machine if possible */
if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
irlmp_udata_indication(lsap, skb);
else
irlmp_do_lsap_event(lsap, LM_UDATA_INDICATION, skb);
} else {
/* Optimize and bypass the state machine if possible */
if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
irlmp_data_indication(lsap, skb);
else
irlmp_do_lsap_event(lsap, LM_DATA_INDICATION, skb);
}
}
/*
* Function irlmp_link_unitdata_indication (self, skb)
*
*
*
*/
#ifdef CONFIG_IRDA_ULTRA
void irlmp_link_unitdata_indication(struct lap_cb *self, struct sk_buff *skb)
{
struct lsap_cb *lsap;
__u8 slsap_sel; /* Source (this) LSAP address */
__u8 dlsap_sel; /* Destination LSAP address */
__u8 pid; /* Protocol identifier */
__u8 *fp;
unsigned long flags;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
IRDA_ASSERT(skb->len > 2, return;);
fp = skb->data;
/*
* The next statements may be confusing, but we do this so that
* destination LSAP of received frame is source LSAP in our view
*/
slsap_sel = fp[0] & LSAP_MASK;
dlsap_sel = fp[1];
pid = fp[2];
if (pid & 0x80) {
IRDA_DEBUG(0, "%s(), extension in PID not supp!\n",
__func__);
return;
}
/* Check if frame is addressed to the connectionless LSAP */
if ((slsap_sel != LSAP_CONNLESS) || (dlsap_sel != LSAP_CONNLESS)) {
IRDA_DEBUG(0, "%s(), dropping frame!\n", __func__);
return;
}
/* Search the connectionless LSAP */
spin_lock_irqsave(&irlmp->unconnected_lsaps->hb_spinlock, flags);
lsap = (struct lsap_cb *) hashbin_get_first(irlmp->unconnected_lsaps);
while (lsap != NULL) {
/*
* Check if source LSAP and dest LSAP selectors and PID match.
*/
if ((lsap->slsap_sel == slsap_sel) &&
(lsap->dlsap_sel == dlsap_sel) &&
(lsap->pid == pid))
{
break;
}
lsap = (struct lsap_cb *) hashbin_get_next(irlmp->unconnected_lsaps);
}
spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock, flags);
if (lsap)
irlmp_connless_data_indication(lsap, skb);
else {
IRDA_DEBUG(0, "%s(), found no matching LSAP!\n", __func__);
}
}
#endif /* CONFIG_IRDA_ULTRA */
/*
* Function irlmp_link_disconnect_indication (reason, userdata)
*
* IrLAP has disconnected
*
*/
void irlmp_link_disconnect_indication(struct lap_cb *lap,
struct irlap_cb *irlap,
LAP_REASON reason,
struct sk_buff *skb)
{
IRDA_DEBUG(2, "%s()\n", __func__);
IRDA_ASSERT(lap != NULL, return;);
IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);
lap->reason = reason;
lap->daddr = DEV_ADDR_ANY;
/* FIXME: must do something with the skb if any */
/*
* Inform station state machine
*/
irlmp_do_lap_event(lap, LM_LAP_DISCONNECT_INDICATION, NULL);
}
/*
* Function irlmp_link_connect_indication (qos)
*
* Incoming LAP connection!
*
*/
void irlmp_link_connect_indication(struct lap_cb *self, __u32 saddr,
__u32 daddr, struct qos_info *qos,
struct sk_buff *skb)
{
IRDA_DEBUG(4, "%s()\n", __func__);
/* Copy QoS settings for this session */
self->qos = qos;
/* Update destination device address */
self->daddr = daddr;
IRDA_ASSERT(self->saddr == saddr, return;);
irlmp_do_lap_event(self, LM_LAP_CONNECT_INDICATION, skb);
}
/*
* Function irlmp_link_connect_confirm (qos)
*
* LAP connection confirmed!
*
*/
void irlmp_link_connect_confirm(struct lap_cb *self, struct qos_info *qos,
struct sk_buff *skb)
{
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
IRDA_ASSERT(qos != NULL, return;);
/* Don't need use the skb for now */
/* Copy QoS settings for this session */
self->qos = qos;
irlmp_do_lap_event(self, LM_LAP_CONNECT_CONFIRM, NULL);
}
/*
* Function irlmp_link_discovery_indication (self, log)
*
* Device is discovering us
*
* It's not an answer to our own discoveries, just another device trying
* to perform discovery, but we don't want to miss the opportunity
* to exploit this information, because :
* o We may not actively perform discovery (just passive discovery)
* o This type of discovery is much more reliable. In some cases, it
* seem that less than 50% of our discoveries get an answer, while
* we always get ~100% of these.
* o Make faster discovery, statistically divide time of discovery
* events by 2 (important for the latency aspect and user feel)
* o Even is we do active discovery, the other node might not
* answer our discoveries (ex: Palm). The Palm will just perform
* one active discovery and connect directly to us.
*
* However, when both devices discover each other, they might attempt to
* connect to each other following the discovery event, and it would create
* collisions on the medium (SNRM battle).
* The "fix" for that is to disable all connection requests in IrLAP
* for 100ms after a discovery indication by setting the media_busy flag.
* Previously, we used to postpone the event which was quite ugly. Now
* that IrLAP takes care of this problem, just pass the event up...
*
* Jean II
*/
void irlmp_link_discovery_indication(struct lap_cb *self,
discovery_t *discovery)
{
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
/* Add to main log, cleanup */
irlmp_add_discovery(irlmp->cachelog, discovery);
/* Just handle it the same way as a discovery confirm,
* bypass the LM_LAP state machine (see below) */
irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_PASSIVE);
}
/*
* Function irlmp_link_discovery_confirm (self, log)
*
* Called by IrLAP with a list of discoveries after the discovery
* request has been carried out. A NULL log is received if IrLAP
* was unable to carry out the discovery request
*
*/
void irlmp_link_discovery_confirm(struct lap_cb *self, hashbin_t *log)
{
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
/* Add to main log, cleanup */
irlmp_add_discovery_log(irlmp->cachelog, log);
/* Propagate event to various LSAPs registered for it.
* We bypass the LM_LAP state machine because
* 1) We do it regardless of the LM_LAP state
* 2) It doesn't affect the LM_LAP state
* 3) Faster, slimer, simpler, ...
* Jean II */
irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_ACTIVE);
}
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
static inline void irlmp_update_cache(struct lap_cb *lap,
struct lsap_cb *lsap)
{
/* Prevent concurrent read to get garbage */
lap->cache.valid = FALSE;
/* Update cache entry */
lap->cache.dlsap_sel = lsap->dlsap_sel;
lap->cache.slsap_sel = lsap->slsap_sel;
lap->cache.lsap = lsap;
lap->cache.valid = TRUE;
}
#endif
/*
* Function irlmp_find_handle (self, dlsap_sel, slsap_sel, status, queue)
*
* Find handle associated with destination and source LSAP
*
* Any IrDA connection (LSAP/TSAP) is uniquely identified by
* 3 parameters, the local lsap, the remote lsap and the remote address.
* We may initiate multiple connections to the same remote service
* (they will have different local lsap), a remote device may initiate
* multiple connections to the same local service (they will have
* different remote lsap), or multiple devices may connect to the same
* service and may use the same remote lsap (and they will have
* different remote address).
* So, where is the remote address ? Each LAP connection is made with
* a single remote device, so imply a specific remote address.
* Jean II
*/
static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap_sel,
__u8 slsap_sel, int status,
hashbin_t *queue)
{
struct lsap_cb *lsap;
unsigned long flags;
/*
* Optimize for the common case. We assume that the last frame
* received is in the same connection as the last one, so check in
* cache first to avoid the linear search
*/
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
if ((self->cache.valid) &&
(self->cache.slsap_sel == slsap_sel) &&
(self->cache.dlsap_sel == dlsap_sel))
{
return (self->cache.lsap);
}
#endif
spin_lock_irqsave(&queue->hb_spinlock, flags);
lsap = (struct lsap_cb *) hashbin_get_first(queue);
while (lsap != NULL) {
/*
* If this is an incoming connection, then the destination
* LSAP selector may have been specified as LM_ANY so that
* any client can connect. In that case we only need to check
* if the source LSAP (in our view!) match!
*/
if ((status == CONNECT_CMD) &&
(lsap->slsap_sel == slsap_sel) &&
(lsap->dlsap_sel == LSAP_ANY)) {
/* This is where the dest lsap sel is set on incoming
* lsaps */
lsap->dlsap_sel = dlsap_sel;
break;
}
/*
* Check if source LSAP and dest LSAP selectors match.
*/
if ((lsap->slsap_sel == slsap_sel) &&
(lsap->dlsap_sel == dlsap_sel))
break;
lsap = (struct lsap_cb *) hashbin_get_next(queue);
}
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
if(lsap)
irlmp_update_cache(self, lsap);
#endif
spin_unlock_irqrestore(&queue->hb_spinlock, flags);
/* Return what we've found or NULL */
return lsap;
}
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