Revert "remove the strip driver"

This reverts commit 94d9842403f770239a656586442454b7a8f2df29.

Alan says it's not appropriate to remove this driver,
Adrian Bunk also agrees with this revert.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 2829 insertions, 0 deletions

diff --git a/drivers/net/wireless/Kconfig b/drivers/net/wireless/Kconfig
index d5b006f5b86..91fc2c765d9 100644
--- a/drivers/net/wireless/Kconfig
+++ b/drivers/net/wireless/Kconfig
@@ -14,6 +14,30 @@ config WLAN_PRE80211
 	  This option does not affect the kernel build, it only
 	  lets you choose drivers.
 
+config STRIP
+	tristate "STRIP (Metricom starmode radio IP)"
+	depends on INET && WLAN_PRE80211
+	select WIRELESS_EXT
+	---help---
+	  Say Y if you have a Metricom radio and intend to use Starmode Radio
+	  IP. STRIP is a radio protocol developed for the MosquitoNet project
+	  (on the WWW at <http://mosquitonet.stanford.edu/>) to send Internet
+	  traffic using Metricom radios.  Metricom radios are small, battery
+	  powered, 100kbit/sec packet radio transceivers, about the size and
+	  weight of a cellular telephone. (You may also have heard them called
+	  "Metricom modems" but we avoid the term "modem" because it misleads
+	  many people into thinking that you can plug a Metricom modem into a
+	  phone line and use it as a modem.)
+
+	  You can use STRIP on any Linux machine with a serial port, although
+	  it is obviously most useful for people with laptop computers. If you
+	  think you might get a Metricom radio in the future, there is no harm
+	  in saying Y to STRIP now, except that it makes the kernel a bit
+	  bigger.
+
+	  To compile this as a module, choose M here: the module will be
+	  called strip.
+
 config ARLAN
 	tristate "Aironet Arlan 655 & IC2200 DS support"
 	depends on ISA && !64BIT && WLAN_PRE80211
diff --git a/drivers/net/wireless/Makefile b/drivers/net/wireless/Makefile
index 2668934abbf..54a4f6f1db6 100644
--- a/drivers/net/wireless/Makefile
+++ b/drivers/net/wireless/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_IPW2100) += ipw2100.o
 
 obj-$(CONFIG_IPW2200) += ipw2200.o
 
+obj-$(CONFIG_STRIP) += strip.o
 obj-$(CONFIG_ARLAN) += arlan.o 
 
 arlan-objs := arlan-main.o arlan-proc.o
diff --git a/drivers/net/wireless/strip.c b/drivers/net/wireless/strip.c
new file mode 100644
index 00000000000..883af891ebf
--- /dev/null
+++ b/drivers/net/wireless/strip.c
@@ -0,0 +1,2804 @@
+/*
+ * Copyright 1996 The Board of Trustees of The Leland Stanford
+ * Junior University. All Rights Reserved.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies.  Stanford University
+ * makes no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without
+ * express or implied warranty.
+ *
+ * strip.c	This module implements Starmode Radio IP (STRIP)
+ *		for kernel-based devices like TTY.  It interfaces between a
+ *		raw TTY, and the kernel's INET protocol layers (via DDI).
+ *
+ * Version:	@(#)strip.c	1.3	July 1997
+ *
+ * Author:	Stuart Cheshire <cheshire@cs.stanford.edu>
+ *
+ * Fixes:	v0.9 12th Feb 1996 (SC)
+ *		New byte stuffing (2+6 run-length encoding)
+ *		New watchdog timer task
+ *		New Protocol key (SIP0)
+ *		
+ *		v0.9.1 3rd March 1996 (SC)
+ *		Changed to dynamic device allocation -- no more compile
+ *		time (or boot time) limit on the number of STRIP devices.
+ *		
+ *		v0.9.2 13th March 1996 (SC)
+ *		Uses arp cache lookups (but doesn't send arp packets yet)
+ *		
+ *		v0.9.3 17th April 1996 (SC)
+ *		Fixed bug where STR_ERROR flag was getting set unneccessarily
+ *		(causing otherwise good packets to be unneccessarily dropped)
+ *		
+ *		v0.9.4 27th April 1996 (SC)
+ *		First attempt at using "&COMMAND" Starmode AT commands
+ *		
+ *		v0.9.5 29th May 1996 (SC)
+ *		First attempt at sending (unicast) ARP packets
+ *		
+ *		v0.9.6 5th June 1996 (Elliot)
+ *		Put "message level" tags in every "printk" statement
+ *		
+ *		v0.9.7 13th June 1996 (laik)
+ *		Added support for the /proc fs
+ *
+ *              v0.9.8 July 1996 (Mema)
+ *              Added packet logging
+ *
+ *              v1.0 November 1996 (SC)
+ *              Fixed (severe) memory leaks in the /proc fs code
+ *              Fixed race conditions in the logging code
+ *
+ *              v1.1 January 1997 (SC)
+ *              Deleted packet logging (use tcpdump instead)
+ *              Added support for Metricom Firmware v204 features
+ *              (like message checksums)
+ *
+ *              v1.2 January 1997 (SC)
+ *              Put portables list back in
+ *
+ *              v1.3 July 1997 (SC)
+ *              Made STRIP driver set the radio's baud rate automatically.
+ *              It is no longer necessarily to manually set the radio's
+ *              rate permanently to 115200 -- the driver handles setting
+ *              the rate automatically.
+ */
+
+#ifdef MODULE
+static const char StripVersion[] = "1.3A-STUART.CHESHIRE-MODULAR";
+#else
+static const char StripVersion[] = "1.3A-STUART.CHESHIRE";
+#endif
+
+#define TICKLE_TIMERS 0
+#define EXT_COUNTERS 1
+
+
+/************************************************************************/
+/* Header files								*/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+# include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/in.h>
+#include <linux/tty.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/if_strip.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/serial.h>
+#include <linux/serialP.h>
+#include <linux/rcupdate.h>
+#include <net/arp.h>
+#include <net/net_namespace.h>
+
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/time.h>
+#include <linux/jiffies.h>
+
+/************************************************************************/
+/* Useful structures and definitions					*/
+
+/*
+ * A MetricomKey identifies the protocol being carried inside a Metricom
+ * Starmode packet.
+ */
+
+typedef union {
+	__u8 c[4];
+	__u32 l;
+} MetricomKey;
+
+/*
+ * An IP address can be viewed as four bytes in memory (which is what it is) or as
+ * a single 32-bit long (which is convenient for assignment, equality testing etc.)
+ */
+
+typedef union {
+	__u8 b[4];
+	__u32 l;
+} IPaddr;
+
+/*
+ * A MetricomAddressString is used to hold a printable representation of
+ * a Metricom address.
+ */
+
+typedef struct {
+	__u8 c[24];
+} MetricomAddressString;
+
+/* Encapsulation can expand packet of size x to 65/64x + 1
+ * Sent packet looks like "<CR>*<address>*<key><encaps payload><CR>"
+ *                           1 1   1-18  1  4         ?         1
+ * eg.                     <CR>*0000-1234*SIP0<encaps payload><CR>
+ * We allow 31 bytes for the stars, the key, the address and the <CR>s
+ */
+#define STRIP_ENCAP_SIZE(X) (32 + (X)*65L/64L)
+
+/*
+ * A STRIP_Header is never really sent over the radio, but making a dummy
+ * header for internal use within the kernel that looks like an Ethernet
+ * header makes certain other software happier. For example, tcpdump
+ * already understands Ethernet headers.
+ */
+
+typedef struct {
+	MetricomAddress dst_addr;	/* Destination address, e.g. "0000-1234"   */
+	MetricomAddress src_addr;	/* Source address, e.g. "0000-5678"        */
+	unsigned short protocol;	/* The protocol type, using Ethernet codes */
+} STRIP_Header;
+
+typedef struct {
+	char c[60];
+} MetricomNode;
+
+#define NODE_TABLE_SIZE 32
+typedef struct {
+	struct timeval timestamp;
+	int num_nodes;
+	MetricomNode node[NODE_TABLE_SIZE];
+} MetricomNodeTable;
+
+enum { FALSE = 0, TRUE = 1 };
+
+/*
+ * Holds the radio's firmware version.
+ */
+typedef struct {
+	char c[50];
+} FirmwareVersion;
+
+/*
+ * Holds the radio's serial number.
+ */
+typedef struct {
+	char c[18];
+} SerialNumber;
+
+/*
+ * Holds the radio's battery voltage.
+ */
+typedef struct {
+	char c[11];
+} BatteryVoltage;
+
+typedef struct {
+	char c[8];
+} char8;
+
+enum {
+	NoStructure = 0,	/* Really old firmware */
+	StructuredMessages = 1,	/* Parsable AT response msgs */
+	ChecksummedMessages = 2	/* Parsable AT response msgs with checksums */
+};
+
+struct strip {
+	int magic;
+	/*
+	 * These are pointers to the malloc()ed frame buffers.
+	 */
+
+	unsigned char *rx_buff;	/* buffer for received IP packet */
+	unsigned char *sx_buff;	/* buffer for received serial data */
+	int sx_count;		/* received serial data counter */
+	int sx_size;		/* Serial buffer size           */
+	unsigned char *tx_buff;	/* transmitter buffer           */
+	unsigned char *tx_head;	/* pointer to next byte to XMIT */
+	int tx_left;		/* bytes left in XMIT queue     */
+	int tx_size;		/* Serial buffer size           */
+
+	/*
+	 * STRIP interface statistics.
+	 */
+
+	unsigned long rx_packets;	/* inbound frames counter       */
+	unsigned long tx_packets;	/* outbound frames counter      */
+	unsigned long rx_errors;	/* Parity, etc. errors          */
+	unsigned long tx_errors;	/* Planned stuff                */
+	unsigned long rx_dropped;	/* No memory for skb            */
+	unsigned long tx_dropped;	/* When MTU change              */
+	unsigned long rx_over_errors;	/* Frame bigger then STRIP buf. */
+
+	unsigned long pps_timer;	/* Timer to determine pps       */
+	unsigned long rx_pps_count;	/* Counter to determine pps     */
+	unsigned long tx_pps_count;	/* Counter to determine pps     */
+	unsigned long sx_pps_count;	/* Counter to determine pps     */
+	unsigned long rx_average_pps;	/* rx packets per second * 8    */
+	unsigned long tx_average_pps;	/* tx packets per second * 8    */
+	unsigned long sx_average_pps;	/* sent packets per second * 8  */
+
+#ifdef EXT_COUNTERS
+	unsigned long rx_bytes;		/* total received bytes */
+	unsigned long tx_bytes;		/* total received bytes */
+	unsigned long rx_rbytes;	/* bytes thru radio i/f */
+	unsigned long tx_rbytes;	/* bytes thru radio i/f */
+	unsigned long rx_sbytes;	/* tot bytes thru serial i/f */
+	unsigned long tx_sbytes;	/* tot bytes thru serial i/f */
+	unsigned long rx_ebytes;	/* tot stat/err bytes */
+	unsigned long tx_ebytes;	/* tot stat/err bytes */
+#endif
+
+	/*
+	 * Internal variables.
+	 */
+
+	struct list_head  list;		/* Linked list of devices */
+
+	int discard;			/* Set if serial error          */
+	int working;			/* Is radio working correctly?  */
+	int firmware_level;		/* Message structuring level    */
+	int next_command;		/* Next periodic command        */
+	unsigned int user_baud;		/* The user-selected baud rate  */
+	int mtu;			/* Our mtu (to spot changes!)   */
+	long watchdog_doprobe;		/* Next time to test the radio  */
+	long watchdog_doreset;		/* Time to do next reset        */
+	long gratuitous_arp;		/* Time to send next ARP refresh */
+	long arp_interval;		/* Next ARP interval            */
+	struct timer_list idle_timer;	/* For periodic wakeup calls    */
+	MetricomAddress true_dev_addr;	/* True address of radio        */
+	int manual_dev_addr;		/* Hack: See note below         */
+
+	FirmwareVersion firmware_version;	/* The radio's firmware version */
+	SerialNumber serial_number;	/* The radio's serial number    */
+	BatteryVoltage battery_voltage;	/* The radio's battery voltage  */
+
+	/*
+	 * Other useful structures.
+	 */
+
+	struct tty_struct *tty;		/* ptr to TTY structure         */
+	struct net_device *dev;		/* Our device structure         */
+
+	/*
+	 * Neighbour radio records
+	 */
+
+	MetricomNodeTable portables;
+	MetricomNodeTable poletops;
+};
+
+/*
+ * Note: manual_dev_addr hack
+ * 
+ * It is not possible to change the hardware address of a Metricom radio,
+ * or to send packets with a user-specified hardware source address, thus
+ * trying to manually set a hardware source address is a questionable
+ * thing to do.  However, if the user *does* manually set the hardware
+ * source address of a STRIP interface, then the kernel will believe it,
+ * and use it in certain places. For example, the hardware address listed
+ * by ifconfig will be the manual address, not the true one.
+ * (Both addresses are listed in /proc/net/strip.)
+ * Also, ARP packets will be sent out giving the user-specified address as
+ * the source address, not the real address. This is dangerous, because
+ * it means you won't receive any replies -- the ARP replies will go to
+ * the specified address, which will be some other radio. The case where
+ * this is useful is when that other radio is also connected to the same
+ * machine. This allows you to connect a pair of radios to one machine,
+ * and to use one exclusively for inbound traffic, and the other
+ * exclusively for outbound traffic. Pretty neat, huh?
+ * 
+ * Here's the full procedure to set this up:
+ * 
+ * 1. "slattach" two interfaces, e.g. st0 for outgoing packets,
+ *    and st1 for incoming packets
+ * 
+ * 2. "ifconfig" st0 (outbound radio) to have the hardware address
+ *    which is the real hardware address of st1 (inbound radio).
+ *    Now when it sends out packets, it will masquerade as st1, and
+ *    replies will be sent to that radio, which is exactly what we want.
+ * 
+ * 3. Set the route table entry ("route add default ..." or
+ *    "route add -net ...", as appropriate) to send packets via the st0
+ *    interface (outbound radio). Do not add any route which sends packets
+ *    out via the st1 interface -- that radio is for inbound traffic only.
+ * 
+ * 4. "ifconfig" st1 (inbound radio) to have hardware address zero.
+ *    This tells the STRIP driver to "shut down" that interface and not
+ *    send any packets through it. In particular, it stops sending the
+ *    periodic gratuitous ARP packets that a STRIP interface normally sends.
+ *    Also, when packets arrive on that interface, it will search the
+ *    interface list to see if there is another interface who's manual
+ *    hardware address matches its own real address (i.e. st0 in this
+ *    example) and if so it will transfer ownership of the skbuff to
+ *    that interface, so that it looks to the kernel as if the packet
+ *    arrived on that interface. This is necessary because when the
+ *    kernel sends an ARP packet on st0, it expects to get a reply on
+ *    st0, and if it sees the reply come from st1 then it will ignore
+ *    it (to be accurate, it puts the entry in the ARP table, but
+ *    labelled in such a way that st0 can't use it).
+ * 
+ * Thanks to Petros Maniatis for coming up with the idea of splitting
+ * inbound and outbound traffic between two interfaces, which turned
+ * out to be really easy to implement, even if it is a bit of a hack.
+ * 
+ * Having set a manual address on an interface, you can restore it
+ * to automatic operation (where the address is automatically kept
+ * consistent with the real address of the radio) by setting a manual
+ * address of all ones, e.g. "ifconfig st0 hw strip FFFFFFFFFFFF"
+ * This 'turns off' manual override mode for the device address.
+ * 
+ * Note: The IEEE 802 headers reported in tcpdump will show the *real*
+ * radio addresses the packets were sent and received from, so that you
+ * can see what is really going on with packets, and which interfaces
+ * they are really going through.
+ */
+
+
+/************************************************************************/
+/* Constants								*/
+
+/*
+ * CommandString1 works on all radios
+ * Other CommandStrings are only used with firmware that provides structured responses.
+ * 
+ * ats319=1 Enables Info message for node additions and deletions
+ * ats319=2 Enables Info message for a new best node
+ * ats319=4 Enables checksums
+ * ats319=8 Enables ACK messages
+ */
+
+static const int MaxCommandStringLength = 32;
+static const int CompatibilityCommand = 1;
+
+static const char CommandString0[] = "*&COMMAND*ATS319=7";	/* Turn on checksums & info messages */
+static const char CommandString1[] = "*&COMMAND*ATS305?";	/* Query radio name */
+static const char CommandString2[] = "*&COMMAND*ATS325?";	/* Query battery voltage */
+static const char CommandString3[] = "*&COMMAND*ATS300?";	/* Query version information */
+static const char CommandString4[] = "*&COMMAND*ATS311?";	/* Query poletop list */
+static const char CommandString5[] = "*&COMMAND*AT~LA";		/* Query portables list */
+typedef struct {
+	const char *string;
+	long length;
+} StringDescriptor;
+
+static const StringDescriptor CommandString[] = {
+	{CommandString0, sizeof(CommandString0) - 1},
+	{CommandString1, sizeof(CommandString1) - 1},
+	{CommandString2, sizeof(CommandString2) - 1},
+	{CommandString3, sizeof(CommandString3) - 1},
+	{CommandString4, sizeof(CommandString4) - 1},
+	{CommandString5, sizeof(CommandString5) - 1}
+};
+
+#define GOT_ALL_RADIO_INFO(S)      \
+    ((S)->firmware_version.c[0] && \
+     (S)->battery_voltage.c[0]  && \
+     memcmp(&(S)->true_dev_addr, zero_address.c, sizeof(zero_address)))
+
+static const char hextable[16] = "0123456789ABCDEF";
+
+static const MetricomAddress zero_address;
+static const MetricomAddress broadcast_address =
+    { {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF} };
+
+static const MetricomKey SIP0Key = { "SIP0" };
+static const MetricomKey ARP0Key = { "ARP0" };
+static const MetricomKey ATR_Key = { "ATR " };
+static const MetricomKey ACK_Key = { "ACK_" };
+static const MetricomKey INF_Key = { "INF_" };
+static const MetricomKey ERR_Key = { "ERR_" };
+
+static const long MaxARPInterval = 60 * HZ;	/* One minute */
+
+/*
+ * Maximum Starmode packet length is 1183 bytes. Allowing 4 bytes for
+ * protocol key, 4 bytes for checksum, one byte for CR, and 65/64 expansion
+ * for STRIP encoding, that translates to a maximum payload MTU of 1155.
+ * Note: A standard NFS 1K data packet is a total of 0x480 (1152) bytes
+ * long, including IP header, UDP header, and NFS header. Setting the STRIP
+ * MTU to 1152 allows us to send default sized NFS packets without fragmentation.
+ */
+static const unsigned short MAX_SEND_MTU = 1152;
+static const unsigned short MAX_RECV_MTU = 1500;	/* Hoping for Ethernet sized packets in the future! */
+static const unsigned short DEFAULT_STRIP_MTU = 1152;
+static const int STRIP_MAGIC = 0x5303;
+static const long LongTime = 0x7FFFFFFF;
+
+/************************************************************************/
+/* Global variables							*/
+
+static LIST_HEAD(strip_list);
+static DEFINE_SPINLOCK(strip_lock);
+
+/************************************************************************/
+/* Macros								*/
+
+/* Returns TRUE if text T begins with prefix P */
+#define has_prefix(T,L,P) (((L) >= sizeof(P)-1) && !strncmp((T), (P), sizeof(P)-1))
+
+/* Returns TRUE if text T of length L is equal to string S */
+#define text_equal(T,L,S) (((L) == sizeof(S)-1) && !strncmp((T), (S), sizeof(S)-1))
+
+#define READHEX(X) ((X)>='0' && (X)<='9' ? (X)-'0' :      \
+                    (X)>='a' && (X)<='f' ? (X)-'a'+10 :   \
+                    (X)>='A' && (X)<='F' ? (X)-'A'+10 : 0 )
+
+#define READHEX16(X) ((__u16)(READHEX(X)))
+
+#define READDEC(X) ((X)>='0' && (X)<='9' ? (X)-'0' : 0)
+
+#define ARRAY_END(X) (&((X)[ARRAY_SIZE(X)]))
+
+#define JIFFIE_TO_SEC(X) ((X) / HZ)
+
+
+/************************************************************************/
+/* Utility routines							*/
+
+static int arp_query(unsigned char *haddr, u32 paddr,
+		     struct net_device *dev)
+{
+	struct neighbour *neighbor_entry;
+	int ret = 0;
+
+	neighbor_entry = neigh_lookup(&arp_tbl, &paddr, dev);
+
+	if (neighbor_entry != NULL) {
+		neighbor_entry->used = jiffies;
+		if (neighbor_entry->nud_state & NUD_VALID) {
+			memcpy(haddr, neighbor_entry->ha, dev->addr_len);
+			ret = 1;
+		}
+		neigh_release(neighbor_entry);
+	}
+	return ret;
+}
+
+static void DumpData(char *msg, struct strip *strip_info, __u8 * ptr,
+		     __u8 * end)
+{
+	static const int MAX_DumpData = 80;
+	__u8 pkt_text[MAX_DumpData], *p = pkt_text;
+
+	*p++ = '\"';
+
+	while (ptr < end && p < &pkt_text[MAX_DumpData - 4]) {
+		if (*ptr == '\\') {
+			*p++ = '\\';
+			*p++ = '\\';
+		} else {
+			if (*ptr >= 32 && *ptr <= 126) {
+				*p++ = *ptr;
+			} else {
+				sprintf(p, "\\%02X", *ptr);
+				p += 3;
+			}
+		}
+		ptr++;
+	}
+
+	if (ptr == end)
+		*p++ = '\"';
+	*p++ = 0;
+
+	printk(KERN_INFO "%s: %-13s%s\n", strip_info->dev->name, msg, pkt_text);
+}
+
+
+/************************************************************************/
+/* Byte stuffing/unstuffing routines					*/
+
+/* Stuffing scheme:
+ * 00    Unused (reserved character)
+ * 01-3F Run of 2-64 different characters
+ * 40-7F Run of 1-64 different characters plus a single zero at the end
+ * 80-BF Run of 1-64 of the same character
+ * C0-FF Run of 1-64 zeroes (ASCII 0)
+ */
+
+typedef enum {
+	Stuff_Diff = 0x00,
+	Stuff_DiffZero = 0x40,
+	Stuff_Same = 0x80,
+	Stuff_Zero = 0xC0,
+	Stuff_NoCode = 0xFF,	/* Special code, meaning no code selected */
+
+	Stuff_CodeMask = 0xC0,
+	Stuff_CountMask = 0x3F,
+	Stuff_MaxCount = 0x3F,
+	Stuff_Magic = 0x0D	/* The value we are eliminating */
+} StuffingCode;
+
+/* StuffData encodes the data starting at "src" for "length" bytes.
+ * It writes it to the buffer pointed to by "dst" (which must be at least
+ * as long as 1 + 65/64 of the input length). The output may be up to 1.6%
+ * larger than the input for pathological input, but will usually be smaller.
+ * StuffData returns the new value of the dst pointer as its result.
+ * "code_ptr_ptr" points to a "__u8 *" which is used to hold encoding state
+ * between calls, allowing an encoded packet to be incrementally built up
+ * from small parts. On the first call, the "__u8 *" pointed to should be
+ * initialized to NULL; between subsequent calls the calling routine should
+ * leave the value alone and simply pass it back unchanged so that the
+ * encoder can recover its current state.
+ */
+
+#define StuffData_FinishBlock(X) \
+(*code_ptr = (X) ^ Stuff_Magic, code = Stuff_NoCode)
+
+static __u8 *StuffData(__u8 * src, __u32 length, __u8 * dst,
+		       __u8 ** code_ptr_ptr)
+{
+	__u8 *end = src + length;
+	__u8 *code_ptr = *code_ptr_ptr;
+	__u8 code = Stuff_NoCode, count = 0;
+
+	if (!length)
+		return (dst);
+
+	if (code_ptr) {
+		/*
+		 * Recover state from last call, if applicable
+		 */
+		code = (*code_ptr ^ Stuff_Magic) & Stuff_CodeMask;
+		count = (*code_ptr ^ Stuff_Magic) & Stuff_CountMask;
+	}
+
+	while (src < end) {
+		switch (code) {
+			/* Stuff_NoCode: If no current code, select one */
+		case Stuff_NoCode:
+			/* Record where we're going to put this code */
+			code_ptr = dst++;
+			count = 0;	/* Reset the count (zero means one instance) */
+			/* Tentatively start a new block */
+			if (*src == 0) {
+				code = Stuff_Zero;
+				src++;
+			} else {
+				code = Stuff_Same;
+				*dst++ = *src++ ^ Stuff_Magic;
+			}
+			/* Note: We optimistically assume run of same -- */
+			/* which will be fixed later in Stuff_Same */
+			/* if it turns out not to be true. */
+			break;
+
+			/* Stuff_Zero: We already have at least one zero encoded */
+		case Stuff_Zero:
+			/* If another zero, count it, else finish this code block */
+			if (*src == 0) {
+				count++;
+				src++;
+			} else {
+				StuffData_FinishBlock(Stuff_Zero + count);
+			}
+			break;
+
+			/* Stuff_Same: We already have at least one byte encoded */
+		case Stuff_Same:
+			/* If another one the same, count it */
+			if ((*src ^ Stuff_Magic) == code_ptr[1]) {
+				count++;
+				src++;
+				break;
+			}
+			/* else, this byte does not match this block. */
+			/* If we already have two or more bytes encoded, finish this code block */
+			if (count) {
+				StuffData_FinishBlock(Stuff_Same + count);
+				break;
+			}
+			/* else, we only have one so far, so switch to Stuff_Diff code */
+			code = Stuff_Diff;
+			/* and fall through to Stuff_Diff case below
+			 * Note cunning cleverness here: case Stuff_Diff compares 
+			 * the current character with the previous two to see if it
+			 * has a run of three the same. Won't this be an error if
+			 * there aren't two previous characters stored to compare with?
+			 * No. Because we know the current character is *not* the same
+			 * as the previous one, the first test below will necessarily
+			 * fail and the send half of the "if" won't be executed.
+			 */
+
+			/* Stuff_Diff: We have at least two *different* bytes encoded */
+		case Stuff_Diff:
+			/* If this is a zero, must encode a Stuff_DiffZero, and begin a new block */
+			if (*src == 0) {
+				StuffData_FinishBlock(Stuff_DiffZero +
+						      count);
+			}
+			/* else, if we have three in a row, it is worth starting a Stuff_Same block */
+			else if ((*src ^ Stuff_Magic) == dst[-1]
+				 && dst[-1] == dst[-2]) {
+				/* Back off the last two characters we encoded */
+				code += count - 2;
+				/* Note: "Stuff_Diff + 0" is an illegal code */
+				if (code == Stuff_Diff + 0) {
+					code = Stuff_Same + 0;
+				}
+				StuffData_FinishBlock(code);
+				code_ptr = dst - 2;
+				/* dst[-1] already holds the correct value */
+				count = 2;	/* 2 means three bytes encoded */
+				code = Stuff_Same;
+			}
+			/* else, another different byte, so add it to the block */
+			else {
+				*dst++ = *src ^ Stuff_Magic;
+				count++;
+			}
+			src++;	/* Consume the byte */
+			break;
+		}
+		if (count == Stuff_MaxCount) {
+			StuffData_FinishBlock(code + count);
+		}
+	}
+	if (code == Stuff_NoCode) {
+		*code_ptr_ptr = NULL;
+	} else {
+		*code_ptr_ptr = code_ptr;
+		StuffData_FinishBlock(code + count);
+	}
+	return (dst);
+}
+
+/*
+ * UnStuffData decodes the data at "src", up to (but not including) "end".
+ * It writes the decoded data into the buffer pointed to by "dst", up to a
+ * maximum of "dst_length", and returns the new value of "src" so that a
+ * follow-on call can read more data, continuing from where the first left off.
+ * 
+ * There are three types of results:
+ * 1. The source data runs out before extracting "dst_length" bytes:
+ *    UnStuffData returns NULL to indicate failure.
+ * 2. The source data produces exactly "dst_length" bytes:
+ *    UnStuffData returns new_src = end to indicate that all bytes were consumed.
+ * 3. "dst_length" bytes are extracted, with more remaining.
+ *    UnStuffData returns new_src < end to indicate that there are more bytes
+ *    to be read.
+ * 
+ * Note: The decoding may be destructive, in that it may alter the source
+ * data in the process of decoding it (this is necessary to allow a follow-on
+ * call to resume correctly).
+ */
+
+static __u8 *UnStuffData(__u8 * src, __u8 * end, __u8 * dst,
+			 __u32 dst_length)
+{
+	__u8 *dst_end = dst + dst_length;
+	/* Sanity check */
+	if (!src || !end || !dst || !dst_length)
+		return (NULL);
+	while (src < end && dst < dst_end) {
+		int count = (*src ^ Stuff_Magic) & Stuff_CountMask;
+		switch ((*src ^ Stuff_Magic) & Stuff_CodeMask) {
+		case Stuff_Diff:
+			if (src + 1 + count >= end)
+				return (NULL);
+			do {
+				*dst++ = *++src ^ Stuff_Magic;
+			}
+			while (--count >= 0 && dst < dst_end);
+			if (count < 0)
+				src += 1;
+			else {
+				if (count == 0)
+					*src = Stuff_Same ^ Stuff_Magic;
+				else
+					*src =
+					    (Stuff_Diff +
+					     count) ^ Stuff_Magic;
+			}
+			break;
+		case Stuff_DiffZero:
+			if (src + 1 + count >= end)
+				return (NULL);
+			do {
+				*dst++ = *++src ^ Stuff_Magic;
+			}
+			while (--count >= 0 && dst < dst_end);
+			if (count < 0)
+				*src = Stuff_Zero ^ Stuff_Magic;
+			else
+				*src =
+				    (Stuff_DiffZero + count) ^ Stuff_Magic;
+			break;
+		case Stuff_Same:
+			if (src + 1 >= end)
+				return (NULL);
+			do {
+				*dst++ = src[1] ^ Stuff_Magic;
+			}
+			while (--count >= 0 && dst < dst_end);
+			if (count < 0)
+				src += 2;
+			else
+				*src = (Stuff_Same + count) ^ Stuff_Magic;
+			break;
+		case Stuff_Zero:
+			do {
+				*dst++ = 0;
+			}
+			while (--count >= 0 && dst < dst_end);
+			if (count < 0)
+				src += 1;
+			else
+				*src = (Stuff_Zero + count) ^ Stuff_Magic;
+			break;
+		}
+	}
+	if (dst < dst_end)
+		return (NULL);
+	else
+		return (src);
+}
+
+
+/************************************************************************/
+/* General routines for STRIP						*/
+
+/*
+ * set_baud sets the baud rate to the rate defined by baudcode
+ */
+static void set_baud(struct tty_struct *tty, speed_t baudrate)
+{
+	struct ktermios old_termios;
+
+	mutex_lock(&tty->termios_mutex);
+	old_termios =*(tty->termios);
+	tty_encode_baud_rate(tty, baudrate, baudrate);
+	tty->ops->set_termios(tty, &old_termios);
+	mutex_unlock(&tty->termios_mutex);
+}
+
+/*
+ * Convert a string to a Metricom Address.
+ */
+
+#define IS_RADIO_ADDRESS(p) (                                                 \
+  isdigit((p)[0]) && isdigit((p)[1]) && isdigit((p)[2]) && isdigit((p)[3]) && \
+  (p)[4] == '-' &&                                                            \
+  isdigit((p)[5]) && isdigit((p)[6]) && isdigit((p)[7]) && isdigit((p)[8])    )
+
+static int string_to_radio_address(MetricomAddress * addr, __u8 * p)
+{
+	if (!IS_RADIO_ADDRESS(p))
+		return (1);
+	addr->c[0] = 0;
+	addr->c[1] = 0;
+	addr->c[2] = READHEX(p[0]) << 4 | READHEX(p[1]);
+	addr->c[3] = READHEX(p[2]) << 4 | READHEX(p[3]);
+	addr->c[4] = READHEX(p[5]) << 4 | READHEX(p[6]);
+	addr->c[5] = READHEX(p[7]) << 4 | READHEX(p[8]);
+	return (0);
+}
+
+/*
+ * Convert a Metricom Address to a string.
+ */
+
+static __u8 *radio_address_to_string(const MetricomAddress * addr,
+				     MetricomAddressString * p)
+{
+	sprintf(p->c, "%02X%02X-%02X%02X", addr->c[2], addr->c[3],
+		addr->c[4], addr->c[5]);
+	return (p->c);
+}
+
+/*
+ * Note: Must make sure sx_size is big enough to receive a stuffed
+ * MAX_RECV_MTU packet. Additionally, we also want to ensure that it's
+ * big enough to receive a large radio neighbour list (currently 4K).
+ */
+
+static int allocate_buffers(struct strip *strip_info, int mtu)
+{
+	struct net_device *dev = strip_info->dev;
+	int sx_size = max_t(int, STRIP_ENCAP_SIZE(MAX_RECV_MTU), 4096);
+	int tx_size = STRIP_ENCAP_SIZE(mtu) + MaxCommandStringLength;
+	__u8 *r = kmalloc(MAX_RECV_MTU, GFP_ATOMIC);
+	__u8 *s = kmalloc(sx_size, GFP_ATOMIC);
+	__u8 *t = kmalloc(tx_size, GFP_ATOMIC);
+	if (r && s && t) {
+		strip_info->rx_buff = r;
+		strip_info->sx_buff = s;
+		strip_info->tx_buff = t;
+		strip_info->sx_size = sx_size;
+		strip_info->tx_size = tx_size;
+		strip_info->mtu = dev->mtu = mtu;
+		return (1);
+	}
+	kfree(r);
+	kfree(s);
+	kfree(t);
+	return (0);
+}
+
+/*
+ * MTU has been changed by the IP layer. 
+ * We could be in
+ * an upcall from the tty driver, or in an ip packet queue.
+ */
+static int strip_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct strip *strip_info = netdev_priv(dev);
+	int old_mtu = strip_info->mtu;
+	unsigned char *orbuff = strip_info->rx_buff;
+	unsigned char *osbuff = strip_info->sx_buff;
+	unsigned char *otbuff = strip_info->tx_buff;
+
+	if (new_mtu > MAX_SEND_MTU) {
+		printk(KERN_ERR
+		       "%s: MTU exceeds maximum allowable (%d), MTU change cancelled.\n",
+		       strip_info->dev->name, MAX_SEND_MTU);
+		return -EINVAL;
+	}
+
+	spin_lock_bh(&strip_lock);
+	if (!allocate_buffers(strip_info, new_mtu)) {
+		printk(KERN_ERR "%s: unable to grow strip buffers, MTU change cancelled.\n",
+		       strip_info->dev->name);
+		spin_unlock_bh(&strip_lock);
+		return -ENOMEM;
+	}
+
+	if (strip_info->sx_count) {
+		if (strip_info->sx_count <= strip_info->sx_size)
+			memcpy(strip_info->sx_buff, osbuff,
+			       strip_info->sx_count);
+		else {
+			strip_info->discard = strip_info->sx_count;
+			strip_info->rx_over_errors++;
+		}
+	}
+
+	if (strip_info->tx_left) {
+		if (strip_info->tx_left <= strip_info->tx_size)
+			memcpy(strip_info->tx_buff, strip_info->tx_head,
+			       strip_info->tx_left);
+		else {
+			strip_info->tx_left = 0;
+			strip_info->tx_dropped++;
+		}
+	}
+	strip_info->tx_head = strip_info->tx_buff;
+	spin_unlock_bh(&strip_lock);
+
+	printk(KERN_NOTICE "%s: strip MTU changed fom %d to %d.\n",
+	       strip_info->dev->name, old_mtu, strip_info->mtu);
+
+	kfree(orbuff);
+	kfree(osbuff);
+	kfree(otbuff);
+	return 0;
+}
+
+static void strip_unlock(struct strip *strip_info)
+{
+	/*
+	 * Set the timer to go off in one second.
+	 */
+	strip_info->idle_timer.expires = jiffies + 1 * HZ;
+	add_timer(&strip_info->idle_timer);
+	netif_wake_queue(strip_info->dev);
+}
+
+
+
+/*
+ * If the time is in the near future, time_delta prints the number of
+ * seconds to go into the buffer and returns the address of the buffer.
+ * If the time is not in the near future, it returns the address of the
+ * string "Not scheduled" The buffer must be long enough to contain the
+ * ascii representation of the number plus 9 charactes for the " seconds"
+ * and the null character.
+ */
+#ifdef CONFIG_PROC_FS
+static char *time_delta(char buffer[], long time)
+{
+	time -= jiffies;
+	if (time > LongTime / 2)
+		return ("Not scheduled");
+	if (time < 0)
+		time = 0;	/* Don't print negative times */
+	sprintf(buffer, "%ld seconds", time / HZ);
+	return (buffer);
+}
+
+/* get Nth element of the linked list */
+static struct strip *strip_get_idx(loff_t pos) 
+{
+	struct strip *str;
+	int i = 0;
+
+	list_for_each_entry_rcu(str, &strip_list, list) {
+		if (pos == i)
+			return str;
+		++i;
+	}
+	return NULL;
+}
+
+static void *strip_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	rcu_read_lock();
+	return *pos ? strip_get_idx(*pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *strip_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct list_head *l;
+	struct strip *s;
+
+	++*pos;
+	if (v == SEQ_START_TOKEN)
+		return strip_get_idx(1);
+
+	s = v;
+	l = &s->list;
+	list_for_each_continue_rcu(l, &strip_list) {
+		return list_entry(l, struct strip, list);
+	}
+	return NULL;
+}
+
+static void strip_seq_stop(struct seq_file *seq, void *v)
+{
+	rcu_read_unlock();
+}
+
+static void strip_seq_neighbours(struct seq_file *seq,
+			   const MetricomNodeTable * table,
+			   const char *title)
+{
+	/* We wrap this in a do/while loop, so if the table changes */
+	/* while we're reading it, we just go around and try again. */
+	struct timeval t;
+
+	do {
+		int i;
+		t = table->timestamp;
+		if (table->num_nodes)
+			seq_printf(seq, "\n %s\n", title);
+		for (i = 0; i < table->num_nodes; i++) {
+			MetricomNode node;
+
+			spin_lock_bh(&strip_lock);
+			node = table->node[i];
+			spin_unlock_bh(&strip_lock);
+			seq_printf(seq, "  %s\n", node.c);
+		}
+	} while (table->timestamp.tv_sec != t.tv_sec
+		 || table->timestamp.tv_usec != t.tv_usec);
+}
+
+/*
+ * This function prints radio status information via the seq_file
+ * interface.  The interface takes care of buffer size and over
+ * run issues. 
+ *
+ * The buffer in seq_file is PAGESIZE (4K) 
+ * so this routine should never print more or it will get truncated.
+ * With the maximum of 32 portables and 32 poletops
+ * reported, the routine outputs 3107 bytes into the buffer.
+ */
+static void strip_seq_status_info(struct seq_file *seq, 
+				  const struct strip *strip_info)
+{
+	char temp[32];
+	MetricomAddressString addr_string;
+
+	/* First, we must copy all of our data to a safe place, */
+	/* in case a serial interrupt comes in and changes it.  */
+	int tx_left = strip_info->tx_left;
+	unsigned long rx_average_pps = strip_info->rx_average_pps;
+	unsigned long tx_average_pps = strip_info->tx_average_pps;
+	unsigned long sx_average_pps = strip_info->sx_average_pps;
+	int working = strip_info->working;
+	int firmware_level = strip_info->firmware_level;
+	long watchdog_doprobe = strip_info->watchdog_doprobe;
+	long watchdog_doreset = strip_info->watchdog_doreset;
+	long gratuitous_arp = strip_info->gratuitous_arp;
+	long arp_interval = strip_info->arp_interval;
+	FirmwareVersion firmware_version = strip_info->firmware_version;
+	SerialNumber serial_number = strip_info->serial_number;
+	BatteryVoltage battery_voltage = strip_info->battery_voltage;
+	char *if_name = strip_info->dev->name;
+	MetricomAddress true_dev_addr = strip_info->true_dev_addr;
+	MetricomAddress dev_dev_addr =
+	    *(MetricomAddress *) strip_info->dev->dev_addr;
+	int manual_dev_addr = strip_info->manual_dev_addr;
+#ifdef EXT_COUNTERS
+	unsigned long rx_bytes = strip_info->rx_bytes;
+	unsigned long tx_bytes = strip_info->tx_bytes;
+	unsigned long rx_rbytes = strip_info->rx_rbytes;
+	unsigned long tx_rbytes = strip_info->tx_rbytes;
+	unsigned long rx_sbytes = strip_info->rx_sbytes;
+	unsigned long tx_sbytes = strip_info->tx_sbytes;
+	unsigned long rx_ebytes = strip_info->rx_ebytes;
+	unsigned long tx_ebytes = strip_info->tx_ebytes;
+#endif
+
+	seq_printf(seq, "\nInterface name\t\t%s\n", if_name);
+	seq_printf(seq, " Radio working:\t\t%s\n", working ? "Yes" : "No");
+	radio_address_to_string(&true_dev_addr, &addr_string);
+	seq_printf(seq, " Radio address:\t\t%s\n", addr_string.c);
+	if (manual_dev_addr) {
+		radio_address_to_string(&dev_dev_addr, &addr_string);
+		seq_printf(seq, " Device address:\t%s\n", addr_string.c);
+	}
+	seq_printf(seq, " Firmware version:\t%s", !working ? "Unknown" :
+		     !firmware_level ? "Should be upgraded" :
+		     firmware_version.c);
+	if (firmware_level >= ChecksummedMessages)
+		seq_printf(seq, " (Checksums Enabled)");
+	seq_printf(seq, "\n");
+	seq_printf(seq, " Serial number:\t\t%s\n", serial_number.c);
+	seq_printf(seq, " Battery voltage:\t%s\n", battery_voltage.c);
+	seq_printf(seq, " Transmit queue (bytes):%d\n", tx_left);
+	seq_printf(seq, " Receive packet rate:   %ld packets per second\n",
+		     rx_average_pps / 8);
+	seq_printf(seq, " Transmit packet rate:  %ld packets per second\n",
+		     tx_average_pps / 8);
+	seq_printf(seq, " Sent packet rate:      %ld packets per second\n",
+		     sx_average_pps / 8);
+	seq_printf(seq, " Next watchdog probe:\t%s\n",
+		     time_delta(temp, watchdog_doprobe));
+	seq_printf(seq, " Next watchdog reset:\t%s\n",
+		     time_delta(temp, watchdog_doreset));
+	seq_printf(seq, " Next gratuitous ARP:\t");
+
+	if (!memcmp
+	    (strip_info->dev->dev_addr, zero_address.c,
+	     sizeof(zero_address)))
+		seq_printf(seq, "Disabled\n");
+	else {
+		seq_printf(seq, "%s\n", time_delta(temp, gratuitous_arp));
+		seq_printf(seq, " Next ARP interval:\t%ld seconds\n",
+			     JIFFIE_TO_SEC(arp_interval));
+	}
+
+	if (working) {
+#ifdef EXT_COUNTERS
+		seq_printf(seq, "\n");
+		seq_printf(seq,
+			     " Total bytes:         \trx:\t%lu\ttx:\t%lu\n",
+			     rx_bytes, tx_bytes);
+		seq_printf(seq,
+			     "  thru radio:         \trx:\t%lu\ttx:\t%lu\n",
+			     rx_rbytes, tx_rbytes);
+		seq_printf(seq,
+			     "  thru serial port:   \trx:\t%lu\ttx:\t%lu\n",
+			     rx_sbytes, tx_sbytes);
+		seq_printf(seq,
+			     " Total stat/err bytes:\trx:\t%lu\ttx:\t%lu\n",
+			     rx_ebytes, tx_ebytes);
+#endif
+		strip_seq_neighbours(seq, &strip_info->poletops,
+					"Poletops:");
+		strip_seq_neighbours(seq, &strip_info->portables,
+					"Portables:");
+	}
+}
+
+/*
+ * This function is exports status information from the STRIP driver through
+ * the /proc file system.
+ */
+static int strip_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_printf(seq, "strip_version: %s\n", StripVersion);
+	else
+		strip_seq_status_info(seq, (const struct strip *)v);
+	return 0;
+}
+
+
+static struct seq_operations strip_seq_ops = {
+	.start = strip_seq_start,
+	.next  = strip_seq_next,
+	.stop  = strip_seq_stop,
+	.show  = strip_seq_show,
+};
+
+static int strip_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &strip_seq_ops);
+}
+
+static const struct file_operations strip_seq_fops = {
+	.owner	 = THIS_MODULE,
+	.open    = strip_seq_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+#endif
+
+
+
+/************************************************************************/
+/* Sending routines							*/
+
+static void ResetRadio(struct strip *strip_info)
+{
+	struct tty_struct *tty = strip_info->tty;
+	static const char init[] = "ate0q1dt**starmode\r**";
+	StringDescriptor s = { init, sizeof(init) - 1 };
+
+	/* 
+	 * If the radio isn't working anymore,
+	 * we should clear the old status information.
+	 */
+	if (strip_info->working) {
+		printk(KERN_INFO "%s: No response: Resetting radio.\n",
+		       strip_info->dev->name);
+		strip_info->firmware_version.c[0] = '\0';
+		strip_info->serial_number.c[0] = '\0';
+		strip_info->battery_voltage.c[0] = '\0';
+		strip_info->portables.num_nodes = 0;
+		do_gettimeofday(&strip_info->portables.timestamp);
+		strip_info->poletops.num_nodes = 0;
+		do_gettimeofday(&strip_info->poletops.timestamp);
+	}
+
+	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 = 0;
+	strip_info->tx_average_pps = 0;
+	strip_info->sx_average_pps = 0;
+
+	/* Mark radio address as unknown */
+	*(MetricomAddress *) & strip_info->true_dev_addr = zero_address;
+	if (!strip_info->manual_dev_addr)
+		*(MetricomAddress *) strip_info->dev->dev_addr =
+		    zero_address;
+	strip_info->working = FALSE;
+	strip_info->firmware_level = NoStructure;
+	strip_info->next_command = CompatibilityCommand;
+	strip_info->watchdog_doprobe = jiffies + 10 * HZ;
+	strip_info->watchdog_doreset = jiffies + 1 * HZ;
+
+	/* If the user has selected a baud rate above 38.4 see what magic we have to do */
+	if (strip_info->user_baud > 38400) {
+		/*
+		 * Subtle stuff: Pay attention :-)
+		 * If the serial port is currently at the user's selected (>38.4) rate,
+		 * then we temporarily switch to 19.2 and issue the ATS304 command
+		 * to tell the radio to switch to the user's selected rate.
+		 * If the serial port is not currently at that rate, that means we just
+		 * issued the ATS304 command last time through, so this time we restore
+		 * the user's selected rate and issue the normal starmode reset string.
+		 */
+		if (strip_info->user_baud == tty_get_baud_rate(tty)) {
+			static const char b0[] = "ate0q1s304=57600\r";
+			static const char b1[] = "ate0q1s304=115200\r";
+			static const StringDescriptor baudstring[2] =
+			    { {b0, sizeof(b0) - 1}
+			, {b1, sizeof(b1) - 1}
+			};
+			set_baud(tty, 19200);
+			if (strip_info->user_baud == 57600)
+				s = baudstring[0];
+			else if (strip_info->user_baud == 115200)
+				s = baudstring[1];
+			else
+				s = baudstring[1];	/* For now */
+		} else
+			set_baud(tty, strip_info->user_baud);
+	}
+
+	tty->ops->write(tty, s.string, s.length);
+#ifdef EXT_COUNTERS
+	strip_info->tx_ebytes += s.length;
+#endif
+}
+
+/*
+ * Called by the driver when there's room for more data.  If we have
+ * more packets to send, we send them here.
+ */
+
+static void strip_write_some_more(struct tty_struct *tty)
+{
+	struct strip *strip_info = (struct strip *) tty->disc_data;
+
+	/* 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->ops->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) {
+		__be32 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;
+	__be32 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 (time_after(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, const void *daddr,
+			const 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							*/
+
+/*
+ * This function parses the response to the ATS300? command,
+ * extracting the radio version and serial number.
+ */
+static void get_radio_version(struct strip *strip_info, __u8 * ptr, __u8 * end)
+{
+	__u8 *p, *value_begin, *value_end;
+	int len;
+
+	/* Determine the beginning of the second line of the payload */
+	p = ptr;
+	while (p < end && *p != 10)
+		p++;
+	if (p >= end)
+		return;
+	p++;
+	value_begin = p;
+
+	/* Determine the end of line */
+	while (p < end && *p != 10)
+		p++;
+	if (p >= end)
+		return;
+	value_end = p;
+	p++;
+
+	len = value_end - value_begin;
+	len = min_t(int, len, sizeof(FirmwareVersion) - 1);
+	if (strip_info->firmware_version.c[0] == 0)
+		printk(KERN_INFO "%s: Radio Firmware: %.*s\n",
+		       strip_info->dev->name, len, value_begin);
+	sprintf(strip_info->firmware_version.c, "%.*s", len, value_begin);
+
+	/* Look for the first colon */
+	while (p < end && *p != ':')
+		p++;
+	if (p >= end)
+		return;
+	/* Skip over the space */
+	p += 2;
+	len = sizeof(SerialNumber) - 1;
+	if (p + len <= end) {
+		sprintf(strip_info->serial_number.c, "%.*s", len, p);
+	} else {
+		printk(KERN_DEBUG
+		       "STRIP: radio serial number shorter (%zd) than expected (%d)\n",
+		       end - p, len);
+	}
+}
+
+/*
+ * This function parses the response to the ATS325? command,
+ * extracting the radio battery voltage.
+ */
+static void get_radio_voltage(struct strip *strip_info, __u8 * ptr, __u8 * end)
+{
+	int len;
+
+	len = sizeof(BatteryVoltage) - 1;
+	if (ptr + len <= end) {
+		sprintf(strip_info->battery_voltage.c, "%.*s", len, ptr);
+	} else {
+		printk(KERN_DEBUG
+		       "STRIP: radio voltage string shorter (%zd) than expected (%d)\n",
+		       end - ptr, len);
+	}
+}
+
+/*
+ * This function parses the responses to the AT~LA and ATS311 commands,
+ * which list the radio's neighbours.
+ */
+static void get_radio_neighbours(MetricomNodeTable * table, __u8 * ptr, __u8 * end)
+{
+	table->num_nodes = 0;
+	while (ptr < end && table->num_nodes < NODE_TABLE_SIZE) {
+		MetricomNode *node = &table->node[table->num_nodes++];
+		char *dst = node->c, *limit = dst + sizeof(*node) - 1;
+		while (ptr < end && *ptr <= 32)
+			ptr++;
+		while (ptr < end && dst < limit && *ptr != 10)
+			*dst++ = *ptr++;
+		*dst++ = 0;
+		while (ptr < end && ptr[-1] != 10)
+			ptr++;
+	}
+	do_gettimeofday(&table->timestamp);
+}
+
+static int get_radio_address(struct strip *strip_info, __u8 * p)
+{
+	MetricomAddress addr;
+
+	if (string_to_radio_address(&addr, p))
+		return (1);
+
+	/* See if our radio address has changed */
+	if (memcmp(strip_info->true_dev_addr.c, addr.c, sizeof(addr))) {
+		MetricomAddressString addr_string;
+		radio_address_to_string(&addr, &addr_string);
+		printk(KERN_INFO "%s: Radio address = %s\n",
+		       strip_info->dev->name, addr_string.c);
+		strip_info->true_dev_addr = addr;
+		if (!strip_info->manual_dev_addr)
+			*(MetricomAddress *) strip_info->dev->dev_addr =
+			    addr;
+		/* Give the radio a few seconds to get its head straight, then send an arp */
+		strip_info->gratuitous_arp = jiffies + 15 * HZ;
+		strip_info->arp_interval = 1 * HZ;
+	}
+	return (0);
+}
+
+static int verify_checksum(struct strip *strip_info)
+{
+	__u8 *p = strip_info->sx_buff;
+	__u8 *end = strip_info->sx_buff + strip_info->sx_count - 4;
+	u_short sum =
+	    (READHEX16(end[0]) << 12) | (READHEX16(end[1]) << 8) |
+	    (READHEX16(end[2]) << 4) | (READHEX16(end[3]));
+	while (p < end)
+		sum -= *p++;
+	if (sum == 0 && strip_info->firmware_level == StructuredMessages) {
+		strip_info->firmware_level = ChecksummedMessages;
+		printk(KERN_INFO "%s: Radio provides message checksums\n",
+		       strip_info->dev->name);
+	}
+	return (sum == 0);
+}
+
+static void RecvErr(char *msg, struct strip *strip_info)
+{
+	__u8 *ptr = strip_info->sx_buff;
+	__u8 *end = strip_info->sx_buff + strip_info->sx_count;
+	DumpData(msg, strip_info, ptr, end);
+	strip_info->rx_errors++;
+}
+
+static void RecvErr_Message(struct strip *strip_info, __u8 * sendername,
+			    const __u8 * msg, u_long len)
+{
+	if (has_prefix(msg, len, "001")) {	/* Not in StarMode! */
+		RecvErr("Error Msg:", strip_info);
+		printk(KERN_INFO "%s: Radio %s is not in StarMode\n",
+		       strip_info->dev->name, sendername);
+	}
+
+	else if (has_prefix(msg, len, "002")) {	/* Remap handle */
+		/* We ignore "Remap handle" messages for now */
+	}
+
+	else if (has_prefix(msg, len, "003")) {	/* Can't resolve name */
+		RecvErr("Error Msg:", strip_info);
+		printk(KERN_INFO "%s: Destination radio name is unknown\n",
+		       strip_info->dev->name);
+	}
+
+	else if (has_prefix(msg, len, "004")) {	/* Name too small or missing */
+		strip_info->watchdog_doreset = jiffies + LongTime;
+#if TICKLE_TIMERS
+		{
+			struct timeval tv;
+			do_gettimeofday(&tv);
+			printk(KERN_INFO
+			       "**** Got ERR_004 response         at %02d.%06d\n",
+			       tv.tv_sec % 100, tv.tv_usec);
+		}
+#endif
+		if (!strip_info->working) {
+			strip_info->working = TRUE;
+			printk(KERN_INFO "%s: Radio now in starmode\n",
+			       strip_info->dev->name);
+			/*
+			 * If the radio has just entered a working state, we should do our first
+			 * probe ASAP, so that we find out our radio address etc. without delay.
+			 */
+			strip_info->watchdog_doprobe = jiffies;
+		}
+		if (strip_info->firmware_level == NoStructure && sendername) {
+			strip_info->firmware_level = StructuredMessages;
+			strip_info->next_command = 0;	/* Try to enable checksums ASAP */
+			printk(KERN_INFO
+			       "%s: Radio provides structured messages\n",
+			       strip_info->dev->name);
+		}
+		if (strip_info->firmware_level >= StructuredMessages) {
+			/*
+			 * If this message has a valid checksum on the end, then the call to verify_checksum
+			 * will elevate the firmware_level to ChecksummedMessages for us. (The actual return
+			 * code from verify_checksum is ignored here.)
+			 */
+			verify_checksum(strip_info);
+			/*
+			 * If the radio has structured messages but we don't yet have all our information about it,
+			 * we should do probes without delay, until we have gathered all the information
+			 */
+			if (!GOT_ALL_RADIO_INFO(strip_info))
+				strip_info->watchdog_doprobe = jiffies;
+		}
+	}
+
+	else if (has_prefix(msg, len, "005"))	/* Bad count specification */
+		RecvErr("Error Msg:", strip_info);
+
+	else if (has_prefix(msg, len, "006"))	/* Header too big */
+		RecvErr("Error Msg:", strip_info);
+
+	else if (has_prefix(msg, len, "007")) {	/* Body too big */
+		RecvErr("Error Msg:", strip_info);
+		printk(KERN_ERR
+		       "%s: Error! Packet size too big for radio.\n",
+		       strip_info->dev->name);
+	}
+
+	else if (has_prefix(msg, len, "008")) {	/* Bad character in name */
+		RecvErr("Error Msg:", strip_info);
+		printk(KERN_ERR
+		       "%s: Radio name contains illegal character\n",
+		       strip_info->dev->name);
+	}
+
+	else if (has_prefix(msg, len, "009"))	/* No count or line terminator */
+		RecvErr("Error Msg:", strip_info);
+
+	else if (has_prefix(msg, len, "010"))	/* Invalid checksum */
+		RecvErr("Error Msg:", strip_info);
+
+	else if (has_prefix(msg, len, "011"))	/* Checksum didn't match */
+		RecvErr("Error Msg:", strip_info);
+
+	else if (has_prefix(msg, len, "012"))	/* Failed to transmit packet */
+		RecvErr("Error Msg:", strip_info);
+
+	else
+		RecvErr("Error Msg:", strip_info);
+}
+
+static void process_AT_response(struct strip *strip_info, __u8 * ptr,
+				__u8 * end)
+{
+	u_long len;
+	__u8 *p = ptr;
+	while (p < end && p[-1] != 10)
+		p++;		/* Skip past first newline character */
+	/* Now ptr points to the AT command, and p points to the text of the response. */
+	len = p - ptr;
+
+#if TICKLE_TIMERS
+	{
+		struct timeval tv;
+		do_gettimeofday(&tv);
+		printk(KERN_INFO "**** Got AT response %.7s      at %02d.%06d\n",
+		       ptr, tv.tv_sec % 100, tv.tv_usec);
+	}
+#endif
+
+	if (has_prefix(ptr, len, "ATS300?"))
+		get_radio_version(strip_info, p, end);
+	else if (has_prefix(ptr, len, "ATS305?"))
+		get_radio_address(strip_info, p);
+	else if (has_prefix(ptr, len, "ATS311?"))
+		get_radio_neighbours(&strip_info->poletops, p, end);
+	else if (has_prefix(ptr, len, "ATS319=7"))
+		verify_checksum(strip_info);
+	else if (has_prefix(ptr, len, "ATS325?"))
+		get_radio_voltage(strip_info, p, end);
+	else if (has_prefix(ptr, len, "AT~LA"))
+		get_radio_neighbours(&strip_info->portables, p, end);
+	else
+		RecvErr("Unknown AT Response:", strip_info);
+}
+
+static void process_ACK(struct strip *strip_info, __u8 * ptr, __u8 * end)
+{
+	/* Currently we don't do anything with ACKs from the radio */
+}
+
+static void process_Info(struct strip *strip_info, __u8 * ptr, __u8 * end)
+{
+	if (ptr + 16 > end)
+		RecvErr("Bad Info Msg:", strip_info);
+}
+
+static struct net_device *get_strip_dev(struct strip *strip_info)
+{
+	/* If our hardware address is *manually set* to zero, and we know our */
+	/* real radio hardware address, try to find another strip device that has been */
+	/* manually set to that address that we can 'transfer ownership' of this packet to  */
+	if (strip_info->manual_dev_addr &&
+	    !memcmp(strip_info->dev->dev_addr, zero_address.c,
+		    sizeof(zero_address))
+	    && memcmp(&strip_info->true_dev_addr, zero_address.c,
+		      sizeof(zero_address))) {
+		struct net_device *dev;
+		read_lock_bh(&dev_base_lock);
+		for_each_netdev(&init_net, dev) {
+			if (dev->type == strip_info->dev->type &&
+			    !memcmp(dev->dev_addr,
+				    &strip_info->true_dev_addr,
+				    sizeof(MetricomAddress))) {
+				printk(KERN_INFO
+				       "%s: Transferred packet ownership to %s.\n",
+				       strip_info->dev->name, dev->name);
+				read_unlock_bh(&dev_base_lock);
+				return (dev);
+			}
+		}
+		read_unlock_bh(&dev_base_lock);
+	}
+	return (strip_info->dev);
+}
+
+/*
+ * Send one completely decapsulated datagram to the next layer.
+ */
+
+static void deliver_packet(struct strip *strip_info, STRIP_Header * header,
+			   __u16 packetlen)
+{
+	struct sk_buff *skb = dev_alloc_skb(sizeof(STRIP_Header) + packetlen);
+	if (!skb) {
+		printk(KERN_ERR "%s: memory squeeze, dropping packet.\n",
+		       strip_info->dev->name);
+		strip_info->rx_dropped++;
+	} else {
+		memcpy(skb_put(skb, sizeof(STRIP_Header)), header,
+		       sizeof(STRIP_Header));
+		memcpy(skb_put(skb, packetlen), strip_info->rx_buff,
+		       packetlen);
+		skb->dev = get_strip_dev(strip_info);
+		skb->protocol = header->protocol;
+		skb_reset_mac_header(skb);
+
+		/* Having put a fake header on the front of the sk_buff for the */
+		/* benefit of tools like tcpdump, skb_pull now 'consumes' that  */
+		/* fake header before we hand the packet up to the next layer.  */
+		skb_pull(skb, sizeof(STRIP_Header));
+
+		/* Finally, hand the packet up to the next layer (e.g. IP or ARP, etc.) */
+		strip_info->rx_packets++;
+		strip_info->rx_pps_count++;
+#ifdef EXT_COUNTERS
+		strip_info->rx_bytes += packetlen;
+#endif
+		skb->dev->last_rx = jiffies;
+		netif_rx(skb);
+	}
+}
+
+static void process_IP_packet(struct strip *strip_info,
+			      STRIP_Header * header, __u8 * ptr,
+			      __u8 * end)
+{
+	__u16 packetlen;
+
+	/* Decode start of the IP packet header */
+	ptr = UnStuffData(ptr, end, strip_info->rx_buff, 4);
+	if (!ptr) {
+		RecvErr("IP Packet too short", strip_info);
+		return;
+	}
+
+	packetlen = ((__u16) strip_info->rx_buff[2] << 8) | strip_info->rx_buff[3];
+
+	if (packetlen > MAX_RECV_MTU) {
+		printk(KERN_INFO "%s: Dropping oversized received IP packet: %d bytes\n",
+		       strip_info->dev->name, packetlen);
+		strip_info->rx_dropped++;
+		return;
+	}
+
+	/*printk(KERN_INFO "%s: Got %d byte IP packet\n", strip_info->dev->name, packetlen); */
+
+	/* Decode remainder of the IP packet */
+	ptr =
+	    UnStuffData(ptr, end, strip_info->rx_buff + 4, packetlen - 4);
+	if (!ptr) {
+		RecvErr("IP Packet too short", strip_info);
+		return;
+	}
+
+	if (ptr < end) {
+		RecvErr("IP Packet too long", strip_info);
+		return;
+	}
+
+	header->protocol = htons(ETH_P_IP);
+
+	deliver_packet(strip_info, header, packetlen);
+}
+
+static void process_ARP_packet(struct strip *strip_info,
+			       STRIP_Header * header, __u8 * ptr,
+			       __u8 * end)
+{
+	__u16 packetlen;
+	struct arphdr *arphdr = (struct arphdr *) strip_info->rx_buff;
+
+	/* Decode start of the ARP packet */
+	ptr = UnStuffData(ptr, end, strip_info->rx_buff, 8);
+	if (!ptr) {
+		RecvErr("ARP Packet too short", strip_info);
+		return;
+	}
+
+	packetlen = 8 + (arphdr->ar_hln + arphdr->ar_pln) * 2;
+
+	if (packetlen > MAX_RECV_MTU) {
+		printk(KERN_INFO
+		       "%s: Dropping oversized received ARP packet: %d bytes\n",
+		       strip_info->dev->name, packetlen);
+		strip_info->rx_dropped++;
+		return;
+	}
+
+	/*printk(KERN_INFO "%s: Got %d byte ARP %s\n",
+	   strip_info->dev->name, packetlen,
+	   ntohs(arphdr->ar_op) == ARPOP_REQUEST ? "request" : "reply"); */
+
+	/* Decode remainder of the ARP packet */
+	ptr =
+	    UnStuffData(ptr, end, strip_info->rx_buff + 8, packetlen - 8);
+	if (!ptr) {
+		RecvErr("ARP Packet too short", strip_info);
+		return;
+	}
+
+	if (ptr < end) {
+		RecvErr("ARP Packet too long", strip_info);
+		return;
+	}
+
+	header->protocol = htons(ETH_P_ARP);
+
+	deliver_packet(strip_info, header, packetlen);
+}
+
+/*
+ * process_text_message processes a <CR>-terminated block of data received
+ * from the radio that doesn't begin with a '*' character. All normal
+ * Starmode communication messages with the radio begin with a '*',
+ * so any text that does not indicates a serial port error, a radio that
+ * is in Hayes command mode instead of Starmode, or a radio with really
+ * old firmware that doesn't frame its Starmode responses properly.
+ */
+static void process_text_message(struct strip *strip_info)
+{
+	__u8 *msg = strip_info->sx_buff;
+	int len = strip_info->sx_count;
+
+	/* Check for anything that looks like it might be our radio name */
+	/* (This is here for backwards compatibility with old firmware)  */
+	if (len == 9 && get_radio_address(strip_info, msg) == 0)
+		return;
+
+	if (text_equal(msg, len, "OK"))
+		return;		/* Ignore 'OK' responses from prior commands */
+	if (text_equal(msg, len, "ERROR"))
+		return;		/* Ignore 'ERROR' messages */
+	if (has_prefix(msg, len, "ate0q1"))
+		return;		/* Ignore character echo back from the radio */
+
+	/* Catch other error messages */
+	/* (This is here for backwards compatibility with old firmware) */
+	if (has_prefix(msg, len, "ERR_")) {
+		RecvErr_Message(strip_info, NULL, &msg[4], len - 4);
+		return;
+	}
+
+	RecvErr("No initial *", strip_info);
+}
+
+/*
+ * process_message processes a <CR>-terminated block of data received
+ * from the radio. If the radio is not in Starmode or has old firmware,
+ * it may be a line of text in response to an AT command. Ideally, with
+ * a current radio that's properly in Starmode, all data received should
+ * be properly framed and checksummed radio message blocks, containing
+ * either a starmode packet, or a other communication from the radio
+ * firmware, like "INF_" Info messages and &COMMAND responses.
+ */
+static void process_message(struct strip *strip_info)
+{
+	STRIP_Header header = { zero_address, zero_address, 0 };
+	__u8 *ptr = strip_info->sx_buff;
+	__u8 *end = strip_info->sx_buff + strip_info->sx_count;
+	__u8 sendername[32], *sptr = sendername;
+	MetricomKey key;
+
+	/*HexDump("Receiving", strip_info, ptr, end); */
+
+	/* Check for start of address marker, and then skip over it */
+	if (*ptr == '*')
+		ptr++;
+	else {
+		process_text_message(strip_info);
+		return;
+	}
+
+	/* Copy out the return address */
+	while (ptr < end && *ptr != '*'
+	       && sptr < ARRAY_END(sendername) - 1)
+		*sptr++ = *ptr++;
+	*sptr = 0;		/* Null terminate the sender name */
+
+	/* Check for end of address marker, and skip over it */
+	if (ptr >= end || *ptr != '*') {
+		RecvErr("No second *", strip_info);
+		return;
+	}
+	ptr++;			/* Skip the second '*' */
+
+	/* If the sender name is "&COMMAND", ignore this 'packet'       */
+	/* (This is here for backwards compatibility with old firmware) */
+	if (!strcmp(sendername, "&COMMAND")) {
+		strip_info->firmware_level = NoStructure;
+		strip_info->next_command = CompatibilityCommand;
+		return;
+	}
+
+	if (ptr + 4 > end) {
+		RecvErr("No proto key", strip_info);
+		return;
+	}
+
+	/* Get the protocol key out of the buffer */
+	key.c[0] = *ptr++;
+	key.c[1] = *ptr++;
+	key.c[2] = *ptr++;
+	key.c[3] = *ptr++;
+
+	/* If we're using checksums, verify the checksum at the end of the packet */
+	if (strip_info->firmware_level >= ChecksummedMessages) {
+		end -= 4;	/* Chop the last four bytes off the packet (they're the checksum) */
+		if (ptr > end) {
+			RecvErr("Missing Checksum", strip_info);
+			return;
+		}
+		if (!verify_checksum(strip_info)) {
+			RecvErr("Bad Checksum", strip_info);
+			return;
+		}
+	}
+
+	/*printk(KERN_INFO "%s: Got packet from \"%s\".\n", strip_info->dev->name, sendername); */
+
+	/*
+	 * Fill in (pseudo) source and destination addresses in the packet.
+	 * We assume that the destination address was our address (the radio does not
+	 * tell us this). If the radio supplies a source address, then we use it.
+	 */
+	header.dst_addr = strip_info->true_dev_addr;
+	string_to_radio_address(&header.src_addr, sendername);
+
+#ifdef EXT_COUNTERS
+	if (key.l == SIP0Key.l) {
+		strip_info->rx_rbytes += (end - ptr);
+		process_IP_packet(strip_info, &header, ptr, end);
+	} else if (key.l == ARP0Key.l) {
+		strip_info->rx_rbytes += (end - ptr);
+		process_ARP_packet(strip_info, &header, ptr, end);
+	} else if (key.l == ATR_Key.l) {
+		strip_info->rx_ebytes += (end - ptr);
+		process_AT_response(strip_info, ptr, end);
+	} else if (key.l == ACK_Key.l) {
+		strip_info->rx_ebytes += (end - ptr);
+		process_ACK(strip_info, ptr, end);
+	} else if (key.l == INF_Key.l) {
+		strip_info->rx_ebytes += (end - ptr);
+		process_Info(strip_info, ptr, end);
+	} else if (key.l == ERR_Key.l) {
+		strip_info->rx_ebytes += (end - ptr);
+		RecvErr_Message(strip_info, sendername, ptr, end - ptr);
+	} else
+		RecvErr("Unrecognized protocol key", strip_info);
+#else
+	if (key.l == SIP0Key.l)
+		process_IP_packet(strip_info, &header, ptr, end);
+	else if (key.l == ARP0Key.l)
+		process_ARP_packet(strip_info, &header, ptr, end);
+	else if (key.l == ATR_Key.l)
+		process_AT_response(strip_info, ptr, end);
+	else if (key.l == ACK_Key.l)
+		process_ACK(strip_info, ptr, end);
+	else if (key.l == INF_Key.l)
+		process_Info(strip_info, ptr, end);
+	else if (key.l == ERR_Key.l)
+		RecvErr_Message(strip_info, sendername, ptr, end - ptr);
+	else
+		RecvErr("Unrecognized protocol key", strip_info);
+#endif
+}
+
+#define TTYERROR(X) ((X) == TTY_BREAK   ? "Break"            : \
+                     (X) == TTY_FRAME   ? "Framing Error"    : \
+                     (X) == TTY_PARITY  ? "Parity Error"     : \
+                     (X) == TTY_OVERRUN ? "Hardware Overrun" : "Unknown Error")
+
+/*
+ * Handle the 'receiver data ready' interrupt.
+ * This function is called by the 'tty_io' module in the kernel when
+ * a block of STRIP data has been received, which can now be decapsulated
+ * and sent on to some IP layer for further processing.
+ */
+
+static void strip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
+		  char *fp, int count)
+{
+	struct strip *strip_info = (struct strip *) tty->disc_data;
+	const unsigned char *end = cp + count;
+
+	if (!strip_info || strip_info->magic != STRIP_MAGIC
+	    || !netif_running(strip_info->dev))
+		return;
+
+	spin_lock_bh(&strip_lock);
+#if 0
+	{
+		struct timeval tv;
+		do_gettimeofday(&tv);
+		printk(KERN_INFO
+		       "**** strip_receive_buf: %3d bytes at %02d.%06d\n",
+		       count, tv.tv_sec % 100, tv.tv_usec);
+	}
+#endif
+
+#ifdef EXT_COUNTERS
+	strip_info->rx_sbytes += count;
+#endif
+
+	/* Read the characters out of the buffer */
+	while (cp < end) {
+		if (fp && *fp)
+			printk(KERN_INFO "%s: %s on serial port\n",
+			       strip_info->dev->name, TTYERROR(*fp));
+		if (fp && *fp++ && !strip_info->discard) {	/* If there's a serial error, record it */
+			/* If we have some characters in the buffer, discard them */
+			strip_info->discard = strip_info->sx_count;
+			strip_info->rx_errors++;
+		}
+
+		/* Leading control characters (CR, NL, Tab, etc.) are ignored */
+		if (strip_info->sx_count > 0 || *cp >= ' ') {
+			if (*cp == 0x0D) {	/* If end of packet, decide what to do with it */
+				if (strip_info->sx_count > 3000)
+					printk(KERN_INFO
+					       "%s: Cut a %d byte packet (%zd bytes remaining)%s\n",
+					       strip_info->dev->name,
+					       strip_info->sx_count,
+					       end - cp - 1,
+					       strip_info->
+					       discard ? " (discarded)" :
+					       "");
+				if (strip_info->sx_count >
+				    strip_info->sx_size) {
+					strip_info->rx_over_errors++;
+					printk(KERN_INFO
+					       "%s: sx_buff overflow (%d bytes total)\n",
+					       strip_info->dev->name,
+					       strip_info->sx_count);
+				} else if (strip_info->discard)
+					printk(KERN_INFO
+					       "%s: Discarding bad packet (%d/%d)\n",
+					       strip_info->dev->name,
+					       strip_info->discard,
+					       strip_info->sx_count);
+				else
+					process_message(strip_info);
+				strip_info->discard = 0;
+				strip_info->sx_count = 0;
+			} else {
+				/* Make sure we have space in the buffer */
+				if (strip_info->sx_count <
+				    strip_info->sx_size)
+					strip_info->sx_buff[strip_info->
+							    sx_count] =
+					    *cp;
+				strip_info->sx_count++;
+			}
+		}
+		cp++;
+	}
+	spin_unlock_bh(&strip_lock);
+}
+
+
+/************************************************************************/
+/* General control routines						*/
+
+static int set_mac_address(struct strip *strip_info,
+			   MetricomAddress * addr)
+{
+	/*
+	 * We're using a manually specified address if the address is set
+	 * to anything other than all ones. Setting the address to all ones
+	 * disables manual mode and goes back to automatic address determination
+	 * (tracking the true address that the radio has).
+	 */
+	strip_info->manual_dev_addr =
+	    memcmp(addr->c, broadcast_address.c,
+		   sizeof(broadcast_address));
+	if (strip_info->manual_dev_addr)
+		*(MetricomAddress *) strip_info->dev->dev_addr = *addr;
+	else
+		*(MetricomAddress *) strip_info->dev->dev_addr =
+		    strip_info->true_dev_addr;
+	return 0;
+}
+
+static int strip_set_mac_address(struct net_device *dev, void *addr)
+{
+	struct strip *strip_info = netdev_priv(dev);
+	struct sockaddr *sa = addr;
+	printk(KERN_INFO "%s: strip_set_dev_mac_address called\n", dev->name);
+	set_mac_address(strip_info, (MetricomAddress *) sa->sa_data);
+	return 0;
+}
+
+static struct net_device_stats *strip_get_stats(struct net_device *dev)
+{
+	struct strip *strip_info = netdev_priv(dev);
+	static struct net_device_stats stats;
+
+	memset(&stats, 0, sizeof(struct net_device_stats));
+
+	stats.rx_packets = strip_info->rx_packets;
+	stats.tx_packets = strip_info->tx_packets;
+	stats.rx_dropped = strip_info->rx_dropped;
+	stats.tx_dropped = strip_info->tx_dropped;
+	stats.tx_errors = strip_info->tx_errors;
+	stats.rx_errors = strip_info->rx_errors;
+	stats.rx_over_errors = strip_info->rx_over_errors;
+	return (&stats);
+}
+
+
+/************************************************************************/
+/* Opening and closing							*/
+
+/*
+ * Here's the order things happen:
+ * When the user runs "slattach -p strip ..."
+ *  1. The TTY module calls strip_open;;
+ *  2. strip_open calls strip_alloc
+ *  3.                  strip_alloc calls register_netdev
+ *  4.                  register_netdev calls strip_dev_init
+ *  5. then strip_open finishes setting up the strip_info
+ *
+ * When the user runs "ifconfig st<x> up address netmask ..."
+ *  6. strip_open_low gets called
+ *
+ * When the user runs "ifconfig st<x> down"
+ *  7. strip_close_low gets called
+ *
+ * When the user kills the slattach process
+ *  8. strip_close gets called
+ *  9. strip_close calls dev_close
+ * 10. if the device is still up, then dev_close calls strip_close_low
+ * 11. strip_close calls strip_free
+ */
+
+/* Open the low-level part of the STRIP channel. Easy! */
+
+static int strip_open_low(struct net_device *dev)
+{
+	struct strip *strip_info = netdev_priv(dev);
+
+	if (strip_info->tty == NULL)
+		return (-ENODEV);
+
+	if (!allocate_buffers(strip_info, dev->mtu))
+		return (-ENOMEM);
+
+	strip_info->sx_count = 0;
+	strip_info->tx_left = 0;
+
+	strip_info->discard = 0;
+	strip_info->working = FALSE;
+	strip_info->firmware_level = NoStructure;
+	strip_info->next_command = CompatibilityCommand;
+	strip_info->user_baud = tty_get_baud_rate(strip_info->tty);
+
+	printk(KERN_INFO "%s: Initializing Radio.\n",
+	       strip_info->dev->name);
+	ResetRadio(strip_info);
+	strip_info->idle_timer.expires = jiffies + 1 * HZ;
+	add_timer(&strip_info->idle_timer);
+	netif_wake_queue(dev);
+	return (0);
+}
+
+
+/*
+ * Close the low-level part of the STRIP channel. Easy!
+ */
+
+static int strip_close_low(struct net_device *dev)
+{
+	struct strip *strip_info = netdev_priv(dev);
+
+	if (strip_info->tty == NULL)
+		return -EBUSY;
+	strip_info->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+
+	netif_stop_queue(dev);
+
+	/*
+	 * Free all STRIP frame buffers.
+	 */
+	kfree(strip_info->rx_buff);
+	strip_info->rx_buff = NULL;
+	kfree(strip_info->sx_buff);
+	strip_info->sx_buff = NULL;
+	kfree(strip_info->tx_buff);
+	strip_info->tx_buff = NULL;
+
+	del_timer(&strip_info->idle_timer);
+	return 0;
+}
+
+static const struct header_ops strip_header_ops = {
+	.create = strip_header,
+	.rebuild = strip_rebuild_header,
+};
+
+/*
+ * This routine is called by DDI when the
+ * (dynamically assigned) device is registered
+ */
+
+static void strip_dev_setup(struct net_device *dev)
+{
+	/*
+	 * Finish setting up the DEVICE info.
+	 */
+
+	dev->trans_start = 0;
+	dev->last_rx = 0;
+	dev->tx_queue_len = 30;	/* Drop after 30 frames queued */
+
+	dev->flags = 0;
+	dev->mtu = DEFAULT_STRIP_MTU;
+	dev->type = ARPHRD_METRICOM;	/* dtang */
+	dev->hard_header_len = sizeof(STRIP_Header);
+	/*
+	 *  dev->priv             Already holds a pointer to our struct strip
+	 */
+
+	*(MetricomAddress *) & dev->broadcast = broadcast_address;
+	dev->dev_addr[0] = 0;
+	dev->addr_len = sizeof(MetricomAddress);
+
+	/*
+	 * Pointers to interface service routines.
+	 */
+
+	dev->open = strip_open_low;
+	dev->stop = strip_close_low;
+	dev->hard_start_xmit = strip_xmit;
+	dev->header_ops = &strip_header_ops;
+
+	dev->set_mac_address = strip_set_mac_address;
+	dev->get_stats = strip_get_stats;
+	dev->change_mtu = strip_change_mtu;
+}
+
+/*
+ * Free a STRIP channel.
+ */
+
+static void strip_free(struct strip *strip_info)
+{
+	spin_lock_bh(&strip_lock);
+	list_del_rcu(&strip_info->list);
+	spin_unlock_bh(&strip_lock);
+
+	strip_info->magic = 0;
+
+	free_netdev(strip_info->dev);
+}
+
+
+/*
+ * Allocate a new free STRIP channel
+ */
+static struct strip *strip_alloc(void)
+{
+	struct list_head *n;
+	struct net_device *dev;
+	struct strip *strip_info;
+
+	dev = alloc_netdev(sizeof(struct strip), "st%d",
+			   strip_dev_setup);
+
+	if (!dev)
+		return NULL;	/* If no more memory, return */
+
+
+	strip_info = netdev_priv(dev);
+	strip_info->dev = dev;
+
+	strip_info->magic = STRIP_MAGIC;
+	strip_info->tty = NULL;
+
+	strip_info->gratuitous_arp = jiffies + LongTime;
+	strip_info->arp_interval = 0;
+	init_timer(&strip_info->idle_timer);
+	strip_info->idle_timer.data = (long) dev;
+	strip_info->idle_timer.function = strip_IdleTask;
+
+
+	spin_lock_bh(&strip_lock);
+ rescan:
+	/*
+	 * Search the list to find where to put our new entry
+	 * (and in the process decide what channel number it is
+	 * going to be)
+	 */
+	list_for_each(n, &strip_list) {
+		struct strip *s = hlist_entry(n, struct strip, list);
+
+		if (s->dev->base_addr == dev->base_addr) {
+			++dev->base_addr;
+			goto rescan;
+		}
+	}
+
+	sprintf(dev->name, "st%ld", dev->base_addr);
+
+	list_add_tail_rcu(&strip_info->list, &strip_list);
+	spin_unlock_bh(&strip_lock);
+
+	return strip_info;
+}
+
+/*
+ * Open the high-level part of the STRIP channel.
+ * This function is called by the TTY module when the
+ * STRIP line discipline is called for.  Because we are
+ * sure the tty line exists, we only have to link it to
+ * a free STRIP channel...
+ */
+
+static int strip_open(struct tty_struct *tty)
+{
+	struct strip *strip_info = (struct strip *) tty->disc_data;
+
+	/*
+	 * First make sure we're not already connected.
+	 */
+
+	if (strip_info && strip_info->magic == STRIP_MAGIC)
+		return -EEXIST;
+
+	/*
+	 * We need a write method.
+	 */
+
+	if (tty->ops->write == NULL || tty->ops->set_termios == NULL)
+		return -EOPNOTSUPP;
+
+	/*
+	 * OK.  Find a free STRIP channel to use.
+	 */
+	if ((strip_info = strip_alloc()) == NULL)
+		return -ENFILE;
+
+	/*
+	 * Register our newly created device so it can be ifconfig'd
+	 * strip_dev_init() will be called as a side-effect
+	 */
+
+	if (register_netdev(strip_info->dev) != 0) {
+		printk(KERN_ERR "strip: register_netdev() failed.\n");
+		strip_free(strip_info);
+		return -ENFILE;
+	}
+
+	strip_info->tty = tty;
+	tty->disc_data = strip_info;
+	tty->receive_room = 65536;
+
+	tty_driver_flush_buffer(tty);
+
+	/*
+	 * Restore default settings
+	 */
+
+	strip_info->dev->type = ARPHRD_METRICOM;	/* dtang */
+
+	/*
+	 * Set tty options
+	 */
+
+	tty->termios->c_iflag |= IGNBRK | IGNPAR;	/* Ignore breaks and parity errors. */
+	tty->termios->c_cflag |= CLOCAL;	/* Ignore modem control signals. */
+	tty->termios->c_cflag &= ~HUPCL;	/* Don't close on hup */
+
+	printk(KERN_INFO "STRIP: device \"%s\" activated\n",
+	       strip_info->dev->name);
+
+	/*
+	 * Done.  We have linked the TTY line to a channel.
+	 */
+	return (strip_info->dev->base_addr);
+}
+
+/*
+ * Close down a STRIP channel.
+ * This means flushing out any pending queues, and then restoring the
+ * TTY line discipline to what it was before it got hooked to STRIP
+ * (which usually is TTY again).
+ */
+
+static void strip_close(struct tty_struct *tty)
+{
+	struct strip *strip_info = (struct strip *) tty->disc_data;
+
+	/*
+	 * First make sure we're connected.
+	 */
+
+	if (!strip_info || strip_info->magic != STRIP_MAGIC)
+		return;
+
+	unregister_netdev(strip_info->dev);
+
+	tty->disc_data = NULL;
+	strip_info->tty = NULL;
+	printk(KERN_INFO "STRIP: device \"%s\" closed down\n",
+	       strip_info->dev->name);
+	strip_free(strip_info);
+	tty->disc_data = NULL;
+}
+
+
+/************************************************************************/
+/* Perform I/O control calls on an active STRIP channel.		*/
+
+static int strip_ioctl(struct tty_struct *tty, struct file *file,
+		       unsigned int cmd, unsigned long arg)
+{
+	struct strip *strip_info = (struct strip *) tty->disc_data;
+
+	/*
+	 * First make sure we're connected.
+	 */
+
+	if (!strip_info || strip_info->magic != STRIP_MAGIC)
+		return -EINVAL;
+
+	switch (cmd) {
+	case SIOCGIFNAME:
+		if(copy_to_user((void __user *) arg, strip_info->dev->name, strlen(strip_info->dev->name) + 1))
+			return -EFAULT;
+		break;
+	case SIOCSIFHWADDR:
+	{
+		MetricomAddress addr;
+		//printk(KERN_INFO "%s: SIOCSIFHWADDR\n", strip_info->dev->name);
+		if(copy_from_user(&addr, (void __user *) arg, sizeof(MetricomAddress)))
+			return -EFAULT;
+		return set_mac_address(strip_info, &addr);
+	}
+	default:
+		return tty_mode_ioctl(tty, file, cmd, arg);
+		break;
+	}
+	return 0;
+}
+
+
+/************************************************************************/
+/* Initialization							*/
+
+static struct tty_ldisc strip_ldisc = {
+	.magic = TTY_LDISC_MAGIC,
+	.name = "strip",
+	.owner = THIS_MODULE,
+	.open = strip_open,
+	.close = strip_close,
+	.ioctl = strip_ioctl,
+	.receive_buf = strip_receive_buf,
+	.write_wakeup = strip_write_some_more,
+};
+
+/*
+ * Initialize the STRIP driver.
+ * This routine is called at boot time, to bootstrap the multi-channel
+ * STRIP driver
+ */
+
+static char signon[] __initdata =
+    KERN_INFO "STRIP: Version %s (unlimited channels)\n";
+
+static int __init strip_init_driver(void)
+{
+	int status;
+
+	printk(signon, StripVersion);
+
+	
+	/*
+	 * Fill in our line protocol discipline, and register it
+	 */
+	if ((status = tty_register_ldisc(N_STRIP, &strip_ldisc)))
+		printk(KERN_ERR "STRIP: can't register line discipline (err = %d)\n",
+		       status);
+
+	/*
+	 * Register the status file with /proc
+	 */
+	proc_net_fops_create(&init_net, "strip", S_IFREG | S_IRUGO, &strip_seq_fops);
+
+	return status;
+}
+
+module_init(strip_init_driver);
+
+static const char signoff[] __exitdata =
+    KERN_INFO "STRIP: Module Unloaded\n";
+
+static void __exit strip_exit_driver(void)
+{
+	int i;
+	struct list_head *p,*n;
+
+	/* module ref count rules assure that all entries are unregistered */
+	list_for_each_safe(p, n, &strip_list) {
+		struct strip *s = list_entry(p, struct strip, list);
+		strip_free(s);
+	}
+
+	/* Unregister with the /proc/net file here. */
+	proc_net_remove(&init_net, "strip");
+
+	if ((i = tty_unregister_ldisc(N_STRIP)))
+		printk(KERN_ERR "STRIP: can't unregister line discipline (err = %d)\n", i);
+
+	printk(signoff);
+}
+
+module_exit(strip_exit_driver);
+
+MODULE_AUTHOR("Stuart Cheshire <cheshire@cs.stanford.edu>");
+MODULE_DESCRIPTION("Starmode Radio IP (STRIP) Device Driver");
+MODULE_LICENSE("Dual BSD/GPL");
+
+MODULE_SUPPORTED_DEVICE("Starmode Radio IP (STRIP) modem");