strip.c

linux和2410结合开发 用他可以生成2410所需的zImage文件

/*
 * 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 <[e-mail]>
 *
 * 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[] = "1.3-STUART.CHESHIRE-MODULAR";
#else
static const char StripVersion[] = "1.3-STUART.CHESHIRE";
#endif

#define TICKLE_TIMERS 0
#define EXT_COUNTERS 1


/************************************************************************/
/* Header files								*/

#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/init.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/segment.h>
#include <asm/bitops.h>

/*
 * isdigit() and isspace() use the ctype[] array, which is not available
 * to kernel modules.  If compiling as a module,  use  a local definition
 * of isdigit() and isspace() until  _ctype is added to ksyms.
 */
#ifdef MODULE
# define isdigit(c) ('0' <= (c) && (c)  <= '9')
# define isspace(c) ((c) == ' ' || (c)  == '\t')
#else
# include <linux/ctype.h>
#endif

#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/serial.h>
#include <linux/serialP.h>
#include <net/arp.h>

#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/time.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 */
} FirmwareLevel;

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 strip      *next;			/* The next struct in the list	*/
    struct strip     **referrer;		/* The pointer that points to us*/
    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