strip.c

linux-2.6.15.6

	/* First make sure we're connected. */
	if (!strip_info || strip_info->magic != STRIP_MAGIC ||
	    !netif_running(strip_info->dev))
		return;

	if (strip_info->tx_left > 0) {
		int num_written =
		    tty->driver->write(tty, strip_info->tx_head,
				      strip_info->tx_left);
		strip_info->tx_left -= num_written;
		strip_info->tx_head += num_written;
#ifdef EXT_COUNTERS
		strip_info->tx_sbytes += num_written;
#endif
	} else {		/* Else start transmission of another packet */

		tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
		strip_unlock(strip_info);
	}
}

static __u8 *add_checksum(__u8 * buffer, __u8 * end)
{
	__u16 sum = 0;
	__u8 *p = buffer;
	while (p < end)
		sum += *p++;
	end[3] = hextable[sum & 0xF];
	sum >>= 4;
	end[2] = hextable[sum & 0xF];
	sum >>= 4;
	end[1] = hextable[sum & 0xF];
	sum >>= 4;
	end[0] = hextable[sum & 0xF];
	return (end + 4);
}

static unsigned char *strip_make_packet(unsigned char *buffer,
					struct strip *strip_info,
					struct sk_buff *skb)
{
	__u8 *ptr = buffer;
	__u8 *stuffstate = NULL;
	STRIP_Header *header = (STRIP_Header *) skb->data;
	MetricomAddress haddr = header->dst_addr;
	int len = skb->len - sizeof(STRIP_Header);
	MetricomKey key;

	/*HexDump("strip_make_packet", strip_info, skb->data, skb->data + skb->len); */

	if (header->protocol == htons(ETH_P_IP))
		key = SIP0Key;
	else if (header->protocol == htons(ETH_P_ARP))
		key = ARP0Key;
	else {
		printk(KERN_ERR
		       "%s: strip_make_packet: Unknown packet type 0x%04X\n",
		       strip_info->dev->name, ntohs(header->protocol));
		return (NULL);
	}

	if (len > strip_info->mtu) {
		printk(KERN_ERR
		       "%s: Dropping oversized transmit packet: %d bytes\n",
		       strip_info->dev->name, len);
		return (NULL);
	}

	/*
	 * If we're sending to ourselves, discard the packet.
	 * (Metricom radios choke if they try to send a packet to their own address.)
	 */
	if (!memcmp(haddr.c, strip_info->true_dev_addr.c, sizeof(haddr))) {
		printk(KERN_ERR "%s: Dropping packet addressed to self\n",
		       strip_info->dev->name);
		return (NULL);
	}

	/*
	 * If this is a broadcast packet, send it to our designated Metricom
	 * 'broadcast hub' radio (First byte of address being 0xFF means broadcast)
	 */
	if (haddr.c[0] == 0xFF) {
		u32 brd = 0;
		struct in_device *in_dev;

		rcu_read_lock();
		in_dev = __in_dev_get_rcu(strip_info->dev);
		if (in_dev == NULL) {
			rcu_read_unlock();
			return NULL;
		}
		if (in_dev->ifa_list)
			brd = in_dev->ifa_list->ifa_broadcast;
		rcu_read_unlock();

		/* arp_query returns 1 if it succeeds in looking up the address, 0 if it fails */
		if (!arp_query(haddr.c, brd, strip_info->dev)) {
			printk(KERN_ERR
			       "%s: Unable to send packet (no broadcast hub configured)\n",
			       strip_info->dev->name);
			return (NULL);
		}
		/*
		 * If we are the broadcast hub, don't bother sending to ourselves.
		 * (Metricom radios choke if they try to send a packet to their own address.)
		 */
		if (!memcmp
		    (haddr.c, strip_info->true_dev_addr.c, sizeof(haddr)))
			return (NULL);
	}

	*ptr++ = 0x0D;
	*ptr++ = '*';
	*ptr++ = hextable[haddr.c[2] >> 4];
	*ptr++ = hextable[haddr.c[2] & 0xF];
	*ptr++ = hextable[haddr.c[3] >> 4];
	*ptr++ = hextable[haddr.c[3] & 0xF];
	*ptr++ = '-';
	*ptr++ = hextable[haddr.c[4] >> 4];
	*ptr++ = hextable[haddr.c[4] & 0xF];
	*ptr++ = hextable[haddr.c[5] >> 4];
	*ptr++ = hextable[haddr.c[5] & 0xF];
	*ptr++ = '*';
	*ptr++ = key.c[0];
	*ptr++ = key.c[1];
	*ptr++ = key.c[2];
	*ptr++ = key.c[3];

	ptr =
	    StuffData(skb->data + sizeof(STRIP_Header), len, ptr,
		      &stuffstate);

	if (strip_info->firmware_level >= ChecksummedMessages)
		ptr = add_checksum(buffer + 1, ptr);

	*ptr++ = 0x0D;
	return (ptr);
}

static void strip_send(struct strip *strip_info, struct sk_buff *skb)
{
	MetricomAddress haddr;
	unsigned char *ptr = strip_info->tx_buff;
	int doreset = (long) jiffies - strip_info->watchdog_doreset >= 0;
	int doprobe = (long) jiffies - strip_info->watchdog_doprobe >= 0
	    && !doreset;
	u32 addr, brd;

	/*
	 * 1. If we have a packet, encapsulate it and put it in the buffer
	 */
	if (skb) {
		char *newptr = strip_make_packet(ptr, strip_info, skb);
		strip_info->tx_pps_count++;
		if (!newptr)
			strip_info->tx_dropped++;
		else {
			ptr = newptr;
			strip_info->sx_pps_count++;
			strip_info->tx_packets++;	/* Count another successful packet */
#ifdef EXT_COUNTERS
			strip_info->tx_bytes += skb->len;
			strip_info->tx_rbytes += ptr - strip_info->tx_buff;
#endif
			/*DumpData("Sending:", strip_info, strip_info->tx_buff, ptr); */
			/*HexDump("Sending", strip_info, strip_info->tx_buff, ptr); */
		}
	}

	/*
	 * 2. If it is time for another tickle, tack it on, after the packet
	 */
	if (doprobe) {
		StringDescriptor ts = CommandString[strip_info->next_command];
#if TICKLE_TIMERS
		{
			struct timeval tv;
			do_gettimeofday(&tv);
			printk(KERN_INFO "**** Sending tickle string %d      at %02d.%06d\n",
			       strip_info->next_command, tv.tv_sec % 100,
			       tv.tv_usec);
		}
#endif
		if (ptr == strip_info->tx_buff)
			*ptr++ = 0x0D;

		*ptr++ = '*';	/* First send "**" to provoke an error message */
		*ptr++ = '*';

		/* Then add the command */
		memcpy(ptr, ts.string, ts.length);

		/* Add a checksum ? */
		if (strip_info->firmware_level < ChecksummedMessages)
			ptr += ts.length;
		else
			ptr = add_checksum(ptr, ptr + ts.length);

		*ptr++ = 0x0D;	/* Terminate the command with a <CR> */

		/* Cycle to next periodic command? */
		if (strip_info->firmware_level >= StructuredMessages)
			if (++strip_info->next_command >=
			    ARRAY_SIZE(CommandString))
				strip_info->next_command = 0;
#ifdef EXT_COUNTERS
		strip_info->tx_ebytes += ts.length;
#endif
		strip_info->watchdog_doprobe = jiffies + 10 * HZ;
		strip_info->watchdog_doreset = jiffies + 1 * HZ;
		/*printk(KERN_INFO "%s: Routine radio test.\n", strip_info->dev->name); */
	}

	/*
	 * 3. Set up the strip_info ready to send the data (if any).
	 */
	strip_info->tx_head = strip_info->tx_buff;
	strip_info->tx_left = ptr - strip_info->tx_buff;
	strip_info->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);

	/*
	 * 4. Debugging check to make sure we're not overflowing the buffer.
	 */
	if (strip_info->tx_size - strip_info->tx_left < 20)
		printk(KERN_ERR "%s: Sending%5d bytes;%5d bytes free.\n",
		       strip_info->dev->name, strip_info->tx_left,
		       strip_info->tx_size - strip_info->tx_left);

	/*
	 * 5. If watchdog has expired, reset the radio. Note: if there's data waiting in
	 * the buffer, strip_write_some_more will send it after the reset has finished
	 */
	if (doreset) {
		ResetRadio(strip_info);
		return;
	}

	if (1) {
		struct in_device *in_dev;

		brd = addr = 0;
		rcu_read_lock();
		in_dev = __in_dev_get_rcu(strip_info->dev);
		if (in_dev) {
			if (in_dev->ifa_list) {
				brd = in_dev->ifa_list->ifa_broadcast;
				addr = in_dev->ifa_list->ifa_local;
			}
		}
		rcu_read_unlock();
	}


	/*
	 * 6. If it is time for a periodic ARP, queue one up to be sent.
	 * We only do this if:
	 *  1. The radio is working
	 *  2. It's time to send another periodic ARP
	 *  3. We really know what our address is (and it is not manually set to zero)
	 *  4. We have a designated broadcast address configured
	 * If we queue up an ARP packet when we don't have a designated broadcast
	 * address configured, then the packet will just have to be discarded in
	 * strip_make_packet. This is not fatal, but it causes misleading information
	 * to be displayed in tcpdump. tcpdump will report that periodic APRs are
	 * being sent, when in fact they are not, because they are all being dropped
	 * in the strip_make_packet routine.
	 */
	if (strip_info->working
	    && (long) jiffies - strip_info->gratuitous_arp >= 0
	    && memcmp(strip_info->dev->dev_addr, zero_address.c,
		      sizeof(zero_address))
	    && arp_query(haddr.c, brd, strip_info->dev)) {
		/*printk(KERN_INFO "%s: Sending gratuitous ARP with interval %ld\n",
		   strip_info->dev->name, strip_info->arp_interval / HZ); */
		strip_info->gratuitous_arp =
		    jiffies + strip_info->arp_interval;
		strip_info->arp_interval *= 2;
		if (strip_info->arp_interval > MaxARPInterval)
			strip_info->arp_interval = MaxARPInterval;
		if (addr)
			arp_send(ARPOP_REPLY, ETH_P_ARP, addr,	/* Target address of ARP packet is our address */
				 strip_info->dev,	/* Device to send packet on */
				 addr,	/* Source IP address this ARP packet comes from */
				 NULL,	/* Destination HW address is NULL (broadcast it) */
				 strip_info->dev->dev_addr,	/* Source HW address is our HW address */
				 strip_info->dev->dev_addr);	/* Target HW address is our HW address (redundant) */
	}

	/*
	 * 7. All ready. Start the transmission
	 */
	strip_write_some_more(strip_info->tty);
}

/* Encapsulate a datagram and kick it into a TTY queue. */
static int strip_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct strip *strip_info = netdev_priv(dev);

	if (!netif_running(dev)) {
		printk(KERN_ERR "%s: xmit call when iface is down\n",
		       dev->name);
		return (1);
	}

	netif_stop_queue(dev);

	del_timer(&strip_info->idle_timer);


	if (jiffies - strip_info->pps_timer > HZ) {
		unsigned long t = jiffies - strip_info->pps_timer;
		unsigned long rx_pps_count = (strip_info->rx_pps_count * HZ * 8 + t / 2) / t;
		unsigned long tx_pps_count = (strip_info->tx_pps_count * HZ * 8 + t / 2) / t;
		unsigned long sx_pps_count = (strip_info->sx_pps_count * HZ * 8 + t / 2) / t;

		strip_info->pps_timer = jiffies;
		strip_info->rx_pps_count = 0;
		strip_info->tx_pps_count = 0;
		strip_info->sx_pps_count = 0;

		strip_info->rx_average_pps = (strip_info->rx_average_pps + rx_pps_count + 1) / 2;
		strip_info->tx_average_pps = (strip_info->tx_average_pps + tx_pps_count + 1) / 2;
		strip_info->sx_average_pps = (strip_info->sx_average_pps + sx_pps_count + 1) / 2;

		if (rx_pps_count / 8 >= 10)
			printk(KERN_INFO "%s: WARNING: Receiving %ld packets per second.\n",
			       strip_info->dev->name, rx_pps_count / 8);
		if (tx_pps_count / 8 >= 10)
			printk(KERN_INFO "%s: WARNING: Tx        %ld packets per second.\n",
			       strip_info->dev->name, tx_pps_count / 8);
		if (sx_pps_count / 8 >= 10)
			printk(KERN_INFO "%s: WARNING: Sending   %ld packets per second.\n",
			       strip_info->dev->name, sx_pps_count / 8);
	}

	spin_lock_bh(&strip_lock);

	strip_send(strip_info, skb);

	spin_unlock_bh(&strip_lock);

	if (skb)
		dev_kfree_skb(skb);
	return 0;
}

/*
 * IdleTask periodically calls strip_xmit, so even when we have no IP packets
 * to send for an extended period of time, the watchdog processing still gets
 * done to ensure that the radio stays in Starmode
 */

static void strip_IdleTask(unsigned long parameter)
{
	strip_xmit(NULL, (struct net_device *) parameter);
}

/*
 * Create the MAC header for an arbitrary protocol layer
 *
 * saddr!=NULL        means use this specific address (n/a for Metricom)
 * saddr==NULL        means use default device source address
 * daddr!=NULL        means use this destination address
 * daddr==NULL        means leave destination address alone
 *                 (e.g. unresolved arp -- kernel will call
 *                 rebuild_header later to fill in the address)
 */

static int strip_header(struct sk_buff *skb, struct net_device *dev,
			unsigned short type, void *daddr, void *saddr,
			unsigned len)
{
	struct strip *strip_info = netdev_priv(dev);
	STRIP_Header *header = (STRIP_Header *) skb_push(skb, sizeof(STRIP_Header));

	/*printk(KERN_INFO "%s: strip_header 0x%04X %s\n", dev->name, type,
	   type == ETH_P_IP ? "IP" : type == ETH_P_ARP ? "ARP" : ""); */

	header->src_addr = strip_info->true_dev_addr;
	header->protocol = htons(type);

	/*HexDump("strip_header", netdev_priv(dev), skb->data, skb->data + skb->len); */

	if (!daddr)
		return (-dev->hard_header_len);

	header->dst_addr = *(MetricomAddress *) daddr;
	return (dev->hard_header_len);
}

/*
 * Rebuild the MAC header. This is called after an ARP
 * (or in future other address resolution) has completed on this
 * sk_buff. We now let ARP fill in the other fields.
 * I think this should return zero if packet is ready to send,
 * or non-zero if it needs more time to do an address lookup
 */

static int strip_rebuild_header(struct sk_buff *skb)
{
#ifdef CONFIG_INET
	STRIP_Header *header = (STRIP_Header *) skb->data;

	/* Arp find returns zero if if knows the address, */
	/* or if it doesn't know the address it sends an ARP packet and returns non-zero */
	return arp_find(header->dst_addr.c, skb) ? 1 : 0;
#else
	return 0;
#endif
}


/************************************************************************/
/* Receiving routines							*/

static int strip_receive_room(struct tty_struct *tty)
{
	return 0x10000;		/* We can handle an infinite amount of data. :-) */