sdla_fr.c

讲述linux的初始化过程

				switch(err) {
				case FRRES_CIR_OVERFLOW:
				case FRRES_BUFFER_OVERFLOW:
                			setup_for_delayed_transmit(dev, data,
						len);
           				chan->drvstats_if_send.
						if_send_adptr_bfrs_full ++;
					break;	
				default:
					chan->drvstats_if_send.
						if_send_dlci_disconnected ++;
        				++chan->ifstats.tx_dropped;
        				++card->wandev.stats.tx_dropped;
					break;
				}
			} else {
				chan->drvstats_if_send.
					if_send_bfr_passed_to_adptr++;
				++chan->ifstats.tx_packets;
				++card->wandev.stats.tx_packets;
                                chan->ifstats.tx_bytes += len;
                                card->wandev.stats.tx_bytes += len;
			}
		}
	}

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

        clear_bit(0, (void*)&card->wandev.critical);

	s508_s514_unlock(card,&smp_flags);

        return (netif_queue_stopped(dev));
}



/*============================================================================
 * Setup so that a frame can be transmitted on the occurence of a transmit
 * interrupt.
 */
static void setup_for_delayed_transmit (struct net_device* dev, void* buf,
	unsigned len)
{
        fr_channel_t* chan = dev->priv;
        sdla_t* card = chan->card;
        fr508_flags_t* adptr_flags = card->flags;
        fr_dlci_interface_t* dlci_interface = chan->dlci_int_interface;

        if(chan->transmit_length) {
                printk(KERN_INFO "%s: Big mess in setup_for_del...\n",
				card->devname);
                return;
        }

	if(len > FR_MAX_NO_DATA_BYTES_IN_FRAME) {
		//FIXME: increment some statistic */
		return;
	}

        chan->transmit_length = len;
        memcpy(chan->transmit_buffer, buf, len);

        dlci_interface->gen_interrupt |= FR_INTR_TXRDY;
        dlci_interface->packet_length = len;
        adptr_flags->imask |= FR_INTR_TXRDY;

	card->u.f.tx_interrupts_pending ++;
}


/*============================================================================
 * Check to see if the packet to be transmitted contains a broadcast or
 * multicast source IP address.
 * Return 0 if not broadcast/multicast address, otherwise return 1.
 */

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;
        struct in_device *in_dev;
        fr_channel_t* chan = dev->priv;
 
        /* read the IP source address from the outgoing packet */
        src_ip_addr = *(u32 *)(skb->data + 14);

        /* read the IP broadcast address for the device */
        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;
        }

        /* 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);
                dev_kfree_skb(skb);
                ++ chan->ifstats.tx_dropped;
                return 1;
        }

        /* check if the IP Source Address is a Multicast address */
        if((chan->mc == WANOPT_NO) && (ntohl(src_ip_addr) >= 0xE0000001) &&
                (ntohl(src_ip_addr) <= 0xFFFFFFFE)) {
                printk(KERN_INFO
                        "%s: Multicast Source Address silently discarded\n",
                        card->devname);
                dev_kfree_skb(skb);
                ++ chan->ifstats.tx_dropped;
                return 1;
        }

        return 0;
}

/*============================================================================
 * Reply to UDP Management system.
 * Return nothing.
 */
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;

  
	fr_udp_pkt_t *fr_udp_pkt = (fr_udp_pkt_t *)data; 

	/* Set length of packet */
	len = sizeof(fr_encap_hdr_t)+
	      sizeof(ip_pkt_t)+ 
	      sizeof(udp_pkt_t)+
	      sizeof(wp_mgmt_t)+
	      sizeof(cblock_t)+
	      mbox_len;
 

	/* fill in UDP reply */
	fr_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)+
		     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);
	fr_udp_pkt->udp_pkt.udp_length = temp;
	 
	/* swap UDP ports */
	temp = fr_udp_pkt->udp_pkt.udp_src_port;
	fr_udp_pkt->udp_pkt.udp_src_port = 
			fr_udp_pkt->udp_pkt.udp_dst_port; 
	fr_udp_pkt->udp_pkt.udp_dst_port = temp;



	/* add UDP pseudo header */
	temp = 0x1100;
	*((unsigned short *)
		(fr_udp_pkt->data+mbox_len+even_bound)) = temp;	
	temp = (udp_length<<8)|(udp_length>>8);
	*((unsigned short *)
		(fr_udp_pkt->data+mbox_len+even_bound+2)) = temp;
		 
	/* calculate UDP checksum */
	fr_udp_pkt->udp_pkt.udp_checksum = 0;

	fr_udp_pkt->udp_pkt.udp_checksum = 
		calc_checksum(&data[UDP_OFFSET+sizeof(fr_encap_hdr_t)],
			      udp_length+UDP_OFFSET);

	/* fill in IP length */
	ip_length = udp_length + sizeof(ip_pkt_t);
	temp = (ip_length<<8)|(ip_length>>8);
	fr_udp_pkt->ip_pkt.total_length = temp;
  
	/* swap IP addresses */
	ip_temp = fr_udp_pkt->ip_pkt.ip_src_address;
	fr_udp_pkt->ip_pkt.ip_src_address = 
				fr_udp_pkt->ip_pkt.ip_dst_address;
	fr_udp_pkt->ip_pkt.ip_dst_address = ip_temp;

		 
	/* fill in IP checksum */
	fr_udp_pkt->ip_pkt.hdr_checksum = 0;
	fr_udp_pkt->ip_pkt.hdr_checksum = 
		calc_checksum(&data[sizeof(fr_encap_hdr_t)],
		      	      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;	
}

/*
   If incoming is 0 (outgoing)- if the net numbers is ours make it 0
   if incoming is 1 - if the net number is 0 make it ours 

*/
static void switch_net_numbers(unsigned char *sendpacket, unsigned long network_number, unsigned char incoming)
{
	unsigned long pnetwork_number;

	pnetwork_number = (unsigned long)((sendpacket[14] << 24) + 
			  (sendpacket[15] << 16) + (sendpacket[16] << 8) + 
			  sendpacket[17]);

	if (!incoming) {
		/* If the destination network number is ours, make it 0 */
		if( pnetwork_number == network_number) {
			sendpacket[14] = sendpacket[15] = sendpacket[16] = 
					 sendpacket[17] = 0x00;
		}
	} else {
		/* If the incoming network is 0, make it ours */
		if( pnetwork_number == 0) {
			sendpacket[14] = (unsigned char)(network_number >> 24);
			sendpacket[15] = (unsigned char)((network_number & 
					 0x00FF0000) >> 16);
			sendpacket[16] = (unsigned char)((network_number & 
					 0x0000FF00) >> 8);
			sendpacket[17] = (unsigned char)(network_number & 
					 0x000000FF);
		}
	}


	pnetwork_number = (unsigned long)((sendpacket[26] << 24) + 
			  (sendpacket[27] << 16) + (sendpacket[28] << 8) + 
			  sendpacket[29]);

	if( !incoming ) {
		/* If the source network is ours, make it 0 */
		if( pnetwork_number == network_number) {
			sendpacket[26] = sendpacket[27] = sendpacket[28] = 
					 sendpacket[29] = 0x00;
		}
	} else {
		/* If the source network is 0, make it ours */
		if( pnetwork_number == 0 ) {
			sendpacket[26] = (unsigned char)(network_number >> 24);
			sendpacket[27] = (unsigned char)((network_number & 
					 0x00FF0000) >> 16);
			sendpacket[28] = (unsigned char)((network_number & 
					 0x0000FF00) >> 8);
			sendpacket[29] = (unsigned char)(network_number & 
					 0x000000FF);
		}
	}
} /* switch_net_numbers */

/*============================================================================
 * Get ethernet-style interface statistics.
 * Return a pointer to struct net_device_stats.
 */
static struct net_device_stats* if_stats (struct net_device* dev)
{
	fr_channel_t* chan = dev->priv;
	
	if(chan == NULL)
		return NULL;

	return &chan->ifstats;
}

/****** Interrupt Handlers **************************************************/

/*============================================================================
 * S508 frame relay interrupt service routine.
 */
static void fr_isr (sdla_t* card)
{
	fr508_flags_t* flags = card->flags;
	char *ptr = &flags->iflag;
	int i,err;
	fr_mbox_t* mbox = card->mbox;

	/* This flag prevents nesting of interrupts.  See sdla_isr() routine
         * in sdlamain.c. 
	 */
	card->in_isr = 1;
	
	++card->statistics.isr_entry;

	if(test_bit(1, (void*)&card->wandev.critical)) {
		card->wandev.critical = 0;
		flags->iflag = 0;
		card->in_isr = 0;
		return;
	}

        if(card->hw.type != SDLA_S514) {
		if (test_and_set_bit(0, (void*)&card->wandev.critical)) {
                        printk(KERN_INFO "%s: Critical while in ISR (0x%02X)\n",
                                card->devname, card->wandev.critical);
			++card->statistics.isr_already_critical;
			card->in_isr = 0;
			return;
		}
	}

	switch (flags->iflag) {

                case FR_INTR_RXRDY:  /* receive interrupt */
	    		++card->statistics.isr_rx;
          		rx_intr(card);
            		break;


                case FR_INTR_TXRDY:  /* transmit interrupt */
	    		++ card->statistics.isr_tx; 
			tx_intr(card); 
            		break;

                case FR_INTR_READY:
	    		Intr_test_counter++;
			++card->statistics.isr_intr_test;
	    		break;	

                case FR_INTR_DLC: /* Event interrupt occured */
			mbox->cmd.command = FR_READ_STATUS;
			mbox->cmd.length = 0;
			err = sdla_exec(mbox) ? mbox->cmd.result : CMD_TIMEOUT;
			if (err)
				fr_event(card, err, mbox);
			break;

                case FR_INTR_TIMER:  /* Timer interrupt */
			timer_intr(card);
			break;
	
		default:
	    		++card->statistics.isr_spurious;
            		spur_intr(card);
	    		printk(KERN_INFO "%s: Interrupt Type 0x%02X!\n", 
				card->devname, flags->iflag);
	    
			printk(KERN_INFO "%s: ID Bytes = ",card->devname);
 	    		for(i = 0; i < 8; i ++)
				printk(KERN_INFO "0x%02X ", *(ptr + 0x28 + i));
	   	 	printk(KERN_INFO "\n");	
            
			break;
    	}

	card->in_isr = 0;
	flags->iflag = 0;
        if(card->hw.type != SDLA_S514)
                clear_bit(0, (void*)&card->wandev.critical);
}



/*============================================================================
 * Receive interrupt handler.
 * When a receive interrupt occurs do the following:
 *	1- Find the structure for the dlci that the interrupt occured on
 *      2- If it doesn't exist then print appropriate msg and goto step 8. 
 * 	3- If it exist then copy data to a skb.
 * 	4- If skb contains Sangoma UDP data then process them
 *	5- If skb contains IPXWAN data then send IPXWAN reply packets
 *	6- If skb contains Inverse Arp data then send Inv Arp replies
 *	7- If skb contains any other data then decapsulate the packet and
 *	   send it to the stack.
 * 	8- Release the receive element and update receive pointers on the board 
 */
static void rx_intr (sdla_t* card)
{
	fr_rx_buf_ctl_t* frbuf = card->rxmb;
	fr508_flags_t* flags = card->flags;
	fr_channel_t* chan;
	char *ptr = &flags->iflag;
	struct sk_buff* skb;
	struct net_device* dev;
	void* buf;
	unsigned dlci, len, offs, len_incl_hdr;
	int i, udp_type;	

	if (frbuf->flag != 0x01) {

		printk(KERN_INFO 
			"%s: corrupted Rx buffer @ 0x%X, flag = 0x%02X!\n", 
			card->devname, (unsigned)frbuf, frbuf->flag);
      
		printk(KERN_INFO "%s: ID Bytes = ",card->devname);
 		for(i = 0; i < 8; i ++)
			printk(KERN_INFO "0x%02X ", *(ptr + 0x28 + i));
		printk(KERN_INFO "\n");
	
		++card->statistics.rx_intr_corrupt_rx_bfr;
		return;
	}

	len  = frbuf->length;
	dlci = frbuf->dlci;