irlap_frame.c

linux 内核源代码

/*********************************************************************
 *
 * Filename:      irlap_frame.c
 * Version:       1.0
 * Description:   Build and transmit IrLAP frames
 * Status:        Stable
 * Author:        Dag Brattli <[e-mail]>
 * Created at:    Tue Aug 19 10:27:26 1997
 * Modified at:   Wed Jan  5 08:59:04 2000
 * Modified by:   Dag Brattli <[e-mail]>
 *
 *     Copyright (c) 1998-2000 Dag Brattli <[e-mail]>,
 *     All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes <[e-mail]>
 *
 *     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/if.h>
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/irda.h>

#include <net/pkt_sched.h>
#include <net/sock.h>

#include <asm/byteorder.h>

#include <net/irda/irda.h>
#include <net/irda/irda_device.h>
#include <net/irda/irlap.h>
#include <net/irda/wrapper.h>
#include <net/irda/timer.h>
#include <net/irda/irlap_frame.h>
#include <net/irda/qos.h>

static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
			       int command);

/*
 * Function irlap_insert_info (self, skb)
 *
 *    Insert minimum turnaround time and speed information into the skb. We
 *    need to do this since it's per packet relevant information. Safe to
 *    have this function inlined since it's only called from one place
 */
static inline void irlap_insert_info(struct irlap_cb *self,
				     struct sk_buff *skb)
{
	struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;

	/*
	 * Insert MTT (min. turn time) and speed into skb, so that the
	 * device driver knows which settings to use
	 */
	cb->magic = LAP_MAGIC;
	cb->mtt = self->mtt_required;
	cb->next_speed = self->speed;

	/* Reset */
	self->mtt_required = 0;

	/*
	 * Delay equals negotiated BOFs count, plus the number of BOFs to
	 * force the negotiated minimum turnaround time
	 */
	cb->xbofs = self->bofs_count;
	cb->next_xbofs = self->next_bofs;
	cb->xbofs_delay = self->xbofs_delay;

	/* Reset XBOF's delay (used only for getting min turn time) */
	self->xbofs_delay = 0;
	/* Put the correct xbofs value for the next packet */
	self->bofs_count = self->next_bofs;
}

/*
 * Function irlap_queue_xmit (self, skb)
 *
 *    A little wrapper for dev_queue_xmit, so we can insert some common
 *    code into it.
 */
void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
{
	/* Some common init stuff */
	skb->dev = self->netdev;
	skb_reset_mac_header(skb);
	skb_reset_network_header(skb);
	skb_reset_transport_header(skb);
	skb->protocol = htons(ETH_P_IRDA);
	skb->priority = TC_PRIO_BESTEFFORT;

	irlap_insert_info(self, skb);

	if (unlikely(self->mode & IRDA_MODE_MONITOR)) {
		IRDA_DEBUG(3, "%s(): %s is in monitor mode\n", __FUNCTION__,
			   self->netdev->name);
		dev_kfree_skb(skb);
		return;
	}

	dev_queue_xmit(skb);
}

/*
 * Function irlap_send_snrm_cmd (void)
 *
 *    Transmits a connect SNRM command frame
 */
void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
{
	struct sk_buff *tx_skb;
	struct snrm_frame *frame;
	int ret;

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

	/* Allocate frame */
	tx_skb = alloc_skb(sizeof(struct snrm_frame) +
			   IRLAP_NEGOCIATION_PARAMS_LEN,
			   GFP_ATOMIC);
	if (!tx_skb)
		return;

	frame = (struct snrm_frame *) skb_put(tx_skb, 2);

	/* Insert connection address field */
	if (qos)
		frame->caddr = CMD_FRAME | CBROADCAST;
	else
		frame->caddr = CMD_FRAME | self->caddr;

	/* Insert control field */
	frame->control = SNRM_CMD | PF_BIT;

	/*
	 *  If we are establishing a connection then insert QoS parameters
	 */
	if (qos) {
		skb_put(tx_skb, 9); /* 25 left */
		frame->saddr = cpu_to_le32(self->saddr);
		frame->daddr = cpu_to_le32(self->daddr);

		frame->ncaddr = self->caddr;

		ret = irlap_insert_qos_negotiation_params(self, tx_skb);
		if (ret < 0) {
			dev_kfree_skb(tx_skb);
			return;
		}
	}
	irlap_queue_xmit(self, tx_skb);
}

/*
 * Function irlap_recv_snrm_cmd (skb, info)
 *
 *    Received SNRM (Set Normal Response Mode) command frame
 *
 */
static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
				struct irlap_info *info)
{
	struct snrm_frame *frame;

	if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
		frame = (struct snrm_frame *) skb->data;

		/* Copy the new connection address ignoring the C/R bit */
		info->caddr = frame->ncaddr & 0xFE;

		/* Check if the new connection address is valid */
		if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
			IRDA_DEBUG(3, "%s(), invalid connection address!\n",
				   __FUNCTION__);
			return;
		}

		/* Copy peer device address */
		info->daddr = le32_to_cpu(frame->saddr);
		info->saddr = le32_to_cpu(frame->daddr);

		/* Only accept if addressed directly to us */
		if (info->saddr != self->saddr) {
			IRDA_DEBUG(2, "%s(), not addressed to us!\n",
				   __FUNCTION__);
			return;
		}
		irlap_do_event(self, RECV_SNRM_CMD, skb, info);
	} else {
		/* Signal that this SNRM frame does not contain and I-field */
		irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
	}
}

/*
 * Function irlap_send_ua_response_frame (qos)
 *
 *    Send UA (Unnumbered Acknowledgement) frame
 *
 */
void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
{
	struct sk_buff *tx_skb;
	struct ua_frame *frame;
	int ret;

	IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

	/* Allocate frame */
	tx_skb = alloc_skb(sizeof(struct ua_frame) +
			   IRLAP_NEGOCIATION_PARAMS_LEN,
			   GFP_ATOMIC);
	if (!tx_skb)
		return;

	frame = (struct ua_frame *) skb_put(tx_skb, 10);

	/* Build UA response */
	frame->caddr = self->caddr;
	frame->control = UA_RSP | PF_BIT;

	frame->saddr = cpu_to_le32(self->saddr);
	frame->daddr = cpu_to_le32(self->daddr);

	/* Should we send QoS negotiation parameters? */
	if (qos) {
		ret = irlap_insert_qos_negotiation_params(self, tx_skb);
		if (ret < 0) {
			dev_kfree_skb(tx_skb);
			return;
		}
	}

	irlap_queue_xmit(self, tx_skb);
}


/*
 * Function irlap_send_dm_frame (void)
 *
 *    Send disconnected mode (DM) frame
 *
 */
void irlap_send_dm_frame( struct irlap_cb *self)
{
	struct sk_buff *tx_skb = NULL;
	struct dm_frame *frame;

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

	tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
	if (!tx_skb)
		return;

	frame = (struct dm_frame *)skb_put(tx_skb, 2);

	if (self->state == LAP_NDM)
		frame->caddr = CBROADCAST;
	else
		frame->caddr = self->caddr;

	frame->control = DM_RSP | PF_BIT;

	irlap_queue_xmit(self, tx_skb);
}

/*
 * Function irlap_send_disc_frame (void)
 *
 *    Send disconnect (DISC) frame
 *
 */
void irlap_send_disc_frame(struct irlap_cb *self)
{
	struct sk_buff *tx_skb = NULL;
	struct disc_frame *frame;

	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

	tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
	if (!tx_skb)
		return;

	frame = (struct disc_frame *)skb_put(tx_skb, 2);

	frame->caddr = self->caddr | CMD_FRAME;
	frame->control = DISC_CMD | PF_BIT;

	irlap_queue_xmit(self, tx_skb);
}

/*
 * Function irlap_send_discovery_xid_frame (S, s, command)
 *
 *    Build and transmit a XID (eXchange station IDentifier) discovery
 *    frame.
 */
void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
				    __u8 command, discovery_t *discovery)
{
	struct sk_buff *tx_skb = NULL;
	struct xid_frame *frame;
	__u32 bcast = BROADCAST;
	__u8 *info;

	IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
		   s, S, command);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
	IRDA_ASSERT(discovery != NULL, return;);

	tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
			   GFP_ATOMIC);
	if (!tx_skb)
		return;

	skb_put(tx_skb, 14);
	frame = (struct xid_frame *) tx_skb->data;

	if (command) {
		frame->caddr = CBROADCAST | CMD_FRAME;
		frame->control =  XID_CMD | PF_BIT;
	} else {
		frame->caddr = CBROADCAST;
		frame->control =  XID_RSP | PF_BIT;
	}
	frame->ident = XID_FORMAT;

	frame->saddr = cpu_to_le32(self->saddr);

	if (command)
		frame->daddr = cpu_to_le32(bcast);
	else
		frame->daddr = cpu_to_le32(discovery->data.daddr);

	switch (S) {
	case 1:
		frame->flags = 0x00;
		break;
	case 6:
		frame->flags = 0x01;
		break;
	case 8:
		frame->flags = 0x02;
		break;
	case 16:
		frame->flags = 0x03;
		break;
	default:
		frame->flags = 0x02;
		break;
	}

	frame->slotnr = s;
	frame->version = 0x00;

	/*
	 *  Provide info for final slot only in commands, and for all
	 *  responses. Send the second byte of the hint only if the
	 *  EXTENSION bit is set in the first byte.
	 */
	if (!command || (frame->slotnr == 0xff)) {
		int len;

		if (discovery->data.hints[0] & HINT_EXTENSION) {
			info = skb_put(tx_skb, 2);
			info[0] = discovery->data.hints[0];
			info[1] = discovery->data.hints[1];
		} else {
			info = skb_put(tx_skb, 1);
			info[0] = discovery->data.hints[0];
		}
		info = skb_put(tx_skb, 1);
		info[0] = discovery->data.charset;

		len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
		info = skb_put(tx_skb, len);
		memcpy(info, discovery->data.info, len);
	}
	irlap_queue_xmit(self, tx_skb);
}

/*
 * Function irlap_recv_discovery_xid_rsp (skb, info)
 *
 *    Received a XID discovery response
 *
 */
static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
					 struct sk_buff *skb,
					 struct irlap_info *info)
{
	struct xid_frame *xid;
	discovery_t *discovery = NULL;
	__u8 *discovery_info;
	char *text;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

	if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
		IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
		return;
	}

	xid = (struct xid_frame *) skb->data;

	info->daddr = le32_to_cpu(xid->saddr);
	info->saddr = le32_to_cpu(xid->daddr);

	/* Make sure frame is addressed to us */
	if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
		IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
			   __FUNCTION__);
		return;
	}

	if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
		IRDA_WARNING("%s: kmalloc failed!\n", __FUNCTION__);
		return;
	}

	discovery->data.daddr = info->daddr;
	discovery->data.saddr = self->saddr;
	discovery->timestamp = jiffies;

	IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
		   discovery->data.daddr);

	discovery_info = skb_pull(skb, sizeof(struct xid_frame));

	/* Get info returned from peer */
	discovery->data.hints[0] = discovery_info[0];
	if (discovery_info[0] & HINT_EXTENSION) {
		IRDA_DEBUG(4, "EXTENSION\n");
		discovery->data.hints[1] = discovery_info[1];
		discovery->data.charset = discovery_info[2];
		text = (char *) &discovery_info[3];
	} else {
		discovery->data.hints[1] = 0;
		discovery->data.charset = discovery_info[1];
		text = (char *) &discovery_info[2];
	}
	/*
	 *  Terminate info string, should be safe since this is where the
	 *  FCS bytes resides.
	 */
	skb->data[skb->len] = '\0';
	strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
	discovery->name_len = strlen(discovery->data.info);

	info->discovery = discovery;

	irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
}

/*
 * Function irlap_recv_discovery_xid_cmd (skb, info)
 *
 *    Received a XID discovery command
 *
 */