sdla_chdlc.c

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	if(skb == NULL) {
		/* If we get here, some higher layer thinks we've missed an
		 * tx-done interrupt.
		 */
		printk(KERN_INFO "%s: interface %s got kicked!\n",
			card->devname, dev->name);
		netif_wake_queue(dev);
		return 0;
	}

   	if(ntohs(skb->protocol) != 0x16) {

		/* check the udp packet type */
		udp_type = udp_pkt_type(skb, card);
		if(udp_type == UDP_CPIPE_TYPE) {
                        if(store_udp_mgmt_pkt(UDP_PKT_FRM_STACK, card, skb, dev,
                                chdlc_priv_area))
	                	chdlc_int->interrupt_permission |=
					APP_INT_ON_TIMER;
			return 0;
		}

		/* check to see if the source IP address is a broadcast or */
		/* multicast IP address */
                if(chk_bcast_mcast_addr(card, dev, skb))
                        return 0;
        }

	/* Lock the 508 Card: SMP is supported */
      	if(card->hw.type != SDLA_S514){
		s508_lock(card,&smp_flags);
	} 

    	if(test_and_set_bit(0, (void*)&card->wandev.critical)) {
	
		printk(KERN_INFO "%s: Critical in if_send: %x\n",
					card->wandev.name,card->wandev.critical);
                ++card->wandev.stats.tx_dropped;
#ifdef LINUX_2_1
    		dev_kfree_skb(skb);
#else
                dev_kfree_skb(skb, FREE_WRITE);
#endif	
		if(card->hw.type != SDLA_S514){
			s508_unlock(card,&smp_flags);
		}
		return 0;
	}

	if(card->u.c.state != WAN_CONNECTED)
       		++card->wandev.stats.tx_dropped;

	else if(!skb->protocol)
        	++card->wandev.stats.tx_errors;

	else {
		void* data = skb->data;
		unsigned len = skb->len;
		unsigned char attr;

		/* If it's an API packet pull off the API
		 * header. Also check that the packet size
		 * is larger than the API header
	         */
		if (card->u.c.usedby == API){
			api_tx_hdr_t* api_tx_hdr;

			if (len <= sizeof(api_tx_hdr_t)){
#ifdef LINUX_2_1
 		               	dev_kfree_skb(skb);
#else
                		dev_kfree_skb(skb, FREE_WRITE);
#endif
				++card->wandev.stats.tx_dropped;
				clear_bit(0, (void*)&card->wandev.critical);
				if(card->hw.type != SDLA_S514){
					s508_unlock(card,&smp_flags);
				}
                		return 0;
			}
				
			api_tx_hdr = (api_tx_hdr_t *)data;
			attr = api_tx_hdr->attr;
			data += sizeof(api_tx_hdr_t);
			len -= sizeof(api_tx_hdr_t);
		}

		if(chdlc_send(card, data, len)) {
			netif_stop_queue(dev);
			chdlc_priv_area->tick_counter = jiffies;
			chdlc_int->interrupt_permission |= APP_INT_ON_TX_FRAME;
		}
		else {
			++card->wandev.stats.tx_packets;
                        card->wandev.stats.tx_bytes += len;
		}	
	}

	if (!netif_queue_stopped(dev))
		dev_kfree_skb(skb);

	clear_bit(0, (void*)&card->wandev.critical);
	if(card->hw.type != SDLA_S514){
		s508_unlock(card,&smp_flags);
	}
	return netif_queue_stopped(dev);
}


/*============================================================================
 * Check to see if the packet to be transmitted contains a broadcast or
 * multicast source IP address.
 */

static int chk_bcast_mcast_addr(sdla_t *card, struct net_device* dev,
				struct sk_buff *skb)
{
	u32 src_ip_addr;
        u32 broadcast_ip_addr = 0;
#ifdef LINUX_2_1
        struct in_device *in_dev;
#endif
        /* read the IP source address from the outgoing packet */
        src_ip_addr = *(u32 *)(skb->data + 12);

	/* read the IP broadcast address for the device */
#ifdef LINUX_2_1
        in_dev = dev->ip_ptr;
        if(in_dev != NULL) {
                struct in_ifaddr *ifa= in_dev->ifa_list;
                if(ifa != NULL)
                        broadcast_ip_addr = ifa->ifa_broadcast;
                else
                        return 0;
        }
#else
        broadcast_ip_addr = dev->pa_brdaddr;
#endif
 
        /* check if the IP Source Address is a Broadcast address */
        if((dev->flags & IFF_BROADCAST) && (src_ip_addr == broadcast_ip_addr)) {
                printk(KERN_INFO "%s: Broadcast Source Address silently discarded\n",
				card->devname);
#ifdef LINUX_2_1
                dev_kfree_skb(skb);
#else
                dev_kfree_skb(skb, FREE_WRITE);
#endif
                ++card->wandev.stats.tx_dropped;
                return 1;
        } 

        /* check if the IP Source Address is a Multicast address */
        if((ntohl(src_ip_addr) >= 0xE0000001) &&
		(ntohl(src_ip_addr) <= 0xFFFFFFFE)) {
                printk(KERN_INFO "%s: Multicast Source Address silently discarded\n",
				card->devname);
#ifdef LINUX_2_1
                dev_kfree_skb(skb);
#else
                dev_kfree_skb(skb, FREE_WRITE);
#endif
                ++card->wandev.stats.tx_dropped;
                return 1;
        }

        return 0;
}


/*============================================================================
 * Reply to UDP Management system.
 * Return length of reply.
 */
static int reply_udp( unsigned char *data, unsigned int mbox_len )
{

	unsigned short len, udp_length, temp, ip_length;
	unsigned long ip_temp;
	int even_bound = 0;
  	chdlc_udp_pkt_t *c_udp_pkt = (chdlc_udp_pkt_t *)data;
	 
	/* Set length of packet */
	len = sizeof(ip_pkt_t)+ 
	      sizeof(udp_pkt_t)+
	      sizeof(wp_mgmt_t)+
	      sizeof(cblock_t)+
	      sizeof(trace_info_t)+ 
	      mbox_len;

	/* fill in UDP reply */
	c_udp_pkt->wp_mgmt.request_reply = UDPMGMT_REPLY;
   
	/* fill in UDP length */
	udp_length = sizeof(udp_pkt_t)+ 
		     sizeof(wp_mgmt_t)+
		     sizeof(cblock_t)+
	             sizeof(trace_info_t)+
		     mbox_len; 

 	/* put it on an even boundary */
	if ( udp_length & 0x0001 ) {
		udp_length += 1;
		len += 1;
		even_bound = 1;
	}  

	temp = (udp_length<<8)|(udp_length>>8);
	c_udp_pkt->udp_pkt.udp_length = temp;
		 
	/* swap UDP ports */
	temp = c_udp_pkt->udp_pkt.udp_src_port;
	c_udp_pkt->udp_pkt.udp_src_port = 
			c_udp_pkt->udp_pkt.udp_dst_port; 
	c_udp_pkt->udp_pkt.udp_dst_port = temp;

	/* add UDP pseudo header */
	temp = 0x1100;
	*((unsigned short *)(c_udp_pkt->data+mbox_len+even_bound)) = temp;	
	temp = (udp_length<<8)|(udp_length>>8);
	*((unsigned short *)(c_udp_pkt->data+mbox_len+even_bound+2)) = temp;

		 
	/* calculate UDP checksum */
	c_udp_pkt->udp_pkt.udp_checksum = 0;
	c_udp_pkt->udp_pkt.udp_checksum = calc_checksum(&data[UDP_OFFSET],udp_length+UDP_OFFSET);

	/* fill in IP length */
	ip_length = len;
	temp = (ip_length<<8)|(ip_length>>8);
	c_udp_pkt->ip_pkt.total_length = temp;
  
	/* swap IP addresses */
	ip_temp = c_udp_pkt->ip_pkt.ip_src_address;
	c_udp_pkt->ip_pkt.ip_src_address = c_udp_pkt->ip_pkt.ip_dst_address;
	c_udp_pkt->ip_pkt.ip_dst_address = ip_temp;

	/* fill in IP checksum */
	c_udp_pkt->ip_pkt.hdr_checksum = 0;
	c_udp_pkt->ip_pkt.hdr_checksum = calc_checksum(data,sizeof(ip_pkt_t));

	return len;

} /* reply_udp */

unsigned short calc_checksum (char *data, int len)
{
	unsigned short temp; 
	unsigned long sum=0;
	int i;

	for( i = 0; i <len; i+=2 ) {
		memcpy(&temp,&data[i],2);
		sum += (unsigned long)temp;
	}

	while (sum >> 16 ) {
		sum = (sum & 0xffffUL) + (sum >> 16);
	}

	temp = (unsigned short)sum;
	temp = ~temp;

	if( temp == 0 ) 
		temp = 0xffff;

	return temp;	
}


/*============================================================================
 * Get ethernet-style interface statistics.
 * Return a pointer to struct net_device_stats.
 */
#ifdef LINUX_2_1
static struct net_device_stats* if_stats (struct net_device* dev)
{
	sdla_t *my_card;
	chdlc_private_area_t* chdlc_priv_area = dev->priv;

	my_card = chdlc_priv_area->card;
	return &my_card->wandev.stats; 
}
#else
static struct net_device_stats* if_stats (struct net_device* dev)
{
        sdla_t *my_card;
        chdlc_private_area_t* chdlc_priv_area = dev->priv;

        my_card = chdlc_priv_area->card;
        return &my_card->wandev.stats;
}
#endif

/****** Cisco HDLC Firmware Interface Functions *******************************/

/*============================================================================
 * Read firmware code version.
 *	Put code version as ASCII string in str. 
 */
static int chdlc_read_version (sdla_t* card, char* str)
{
	CHDLC_MAILBOX_STRUCT* mb = card->mbox;
	int len;
	char err;
	mb->buffer_length = 0;
	mb->command = READ_CHDLC_CODE_VERSION;
	err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;

	if(err != COMMAND_OK) {
		chdlc_error(card,err,mb);
	}
	else if (str) {  /* is not null */
		len = mb->buffer_length;
		memcpy(str, mb->data, len);
		str[len] = '\0';
	}
	return (err);
}

/*-----------------------------------------------------------------------------
 *  Configure CHDLC firmware.
 */
static int chdlc_configure (sdla_t* card, void* data)
{
	int err;
	CHDLC_MAILBOX_STRUCT *mailbox = card->mbox;
	int data_length = sizeof(CHDLC_CONFIGURATION_STRUCT);
	
	mailbox->buffer_length = data_length;  
	memcpy(mailbox->data, data, data_length);
	mailbox->command = SET_CHDLC_CONFIGURATION;
	err = sdla_exec(mailbox) ? mailbox->return_code : CMD_TIMEOUT;
	
	if (err != COMMAND_OK) chdlc_error (card, err, mailbox);
                           
	return err;
}


/*============================================================================
 * Set interrupt mode -- HDLC Version.
 */

static int chdlc_set_intr_mode (sdla_t* card, unsigned mode)
{
	CHDLC_MAILBOX_STRUCT* mb = card->mbox;
	CHDLC_INT_TRIGGERS_STRUCT* int_data =
		 (CHDLC_INT_TRIGGERS_STRUCT *)mb->data;
	int err;

	int_data->CHDLC_interrupt_triggers 	= mode;
	int_data->IRQ				= card->hw.irq;
	int_data->interrupt_timer               = 1;
   
	mb->buffer_length = sizeof(CHDLC_INT_TRIGGERS_STRUCT);
	mb->command = SET_CHDLC_INTERRUPT_TRIGGERS;
	err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
	if (err != COMMAND_OK)
		chdlc_error (card, err, mb);
	return err;
}


/*============================================================================
 * Enable communications.
 */

static int chdlc_comm_enable (sdla_t* card)
{
	int err;
	CHDLC_MAILBOX_STRUCT* mb = card->mbox;

	mb->buffer_length = 0;
	mb->command = ENABLE_CHDLC_COMMUNICATIONS;
	err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
	if (err != COMMAND_OK)
		chdlc_error(card, err, mb);
	return err;
}

/*============================================================================
 * Disable communications and Drop the Modem lines (DCD and RTS).
 */
static int chdlc_comm_disable (sdla_t* card)
{
	int err;
	CHDLC_MAILBOX_STRUCT* mb = card->mbox;

	mb->buffer_length = 0;
	mb->command = DISABLE_CHDLC_COMMUNICATIONS;
	err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
	if (err != COMMAND_OK)
		chdlc_error(card,err,mb);

	mb->command = SET_MODEM_STATUS;
	mb->buffer_length = 1;
	mb->data[0] = 0;
	err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
	if (err != COMMAND_OK)
		chdlc_error(card,err,mb);

	return err;
}

/*============================================================================
 * Read communication error statistics.
 */
static int chdlc_read_comm_err_stats (sdla_t* card)
{
        int err;
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;

        mb->buffer_length = 0;
        mb->command = READ_COMMS_ERROR_STATS;
        err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
        if (err != COMMAND_OK)
                chdlc_error(card,err,mb);
        return err;
}


/*============================================================================
 * Read CHDLC operational statistics.
 */
static int chdlc_read_op_stats (sdla_t* card)
{
        int err;
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;

        mb->buffer_length = 0;
        mb->command = READ_CHDLC_OPERATIONAL_STATS;
        err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
        if (err != COMMAND_OK)
                chdlc_error(card,err,mb);
        return err;
}


/*============================================================================
 * Update communications error and general packet statistics.
 */
static int update_comms_stats(sdla_t* card,
	chdlc_private_area_t* chdlc_priv_area)
{
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;
  	COMMS_ERROR_STATS_STRUCT* err_stats;
        CHDLC_OPERATIONAL_STATS_STRUCT *op_stats;