af_wanpipe.c

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/*****************************************************************************
* af_wanpipe.c	WANPIPE(tm) Secure Socket Layer.
*
* Author:	Nenad Corbic	<[e-mail]>
*
* Copyright:	(c) 2000 Sangoma Technologies Inc.
*
*		This program is free software; you can redistribute it and/or
*		modify it under the terms of the GNU General Public License
*		as published by the Free Software Foundation; either version
*		2 of the License, or (at your option) any later version.
* ============================================================================
* Due Credit:
*               Wanpipe socket layer is based on Packet and 
*               the X25 socket layers. The above sockets were 
*               used for the specific use of Sangoma Technoloiges 
*               API programs. 
*               Packet socket Authors: Ross Biro, Fred N. van Kempen and 
*                                      Alan Cox.
*               X25 socket Author: Jonathan Naylor.
* ============================================================================
* Apr 25, 2000  Nenad Corbic     o Added the ability to send zero length packets.
* Mar 13, 2000  Nenad Corbic	 o Added a tx buffer check via ioctl call.
* Mar 06, 2000  Nenad Corbic     o Fixed the corrupt sock lcn problem.
*                                  Server and client applicaton can run
*                                  simultaneously without conflicts.
* Feb 29, 2000  Nenad Corbic     o Added support for PVC protocols, such as
*                                  CHDLC, Frame Relay and HDLC API.
* Jan 17, 2000 	Nenad Corbic	 o Initial version, based on AF_PACKET socket.
*			           X25API support only. 
*
******************************************************************************/

#include <linux/version.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/wireless.h>
#include <linux/kmod.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/wanpipe.h>
#include <linux/if_wanpipe.h>
#include <linux/pkt_sched.h>
#include <linux/tcp.h>
#include <linux/if_wanpipe_common.h>
#include <linux/sdla_x25.h>

#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif

#define SLOW_BACKOFF 0.1*HZ
#define FAST_BACKOFF 0.01*HZ

//#define PRINT_DEBUG
#ifdef PRINT_DEBUG
	#define DBG_PRINTK(format, a...) printk(format, ## a)
#else
	#define DBG_PRINTK(format, a...)
#endif      

#if defined(LINUX_2_1)
 #define dev_put(a)
 #define __sock_put(a)
 #define sock_hold(a)
 #define DECLARE_WAITQUEUE(a,b) \
		struct wait_queue a = { b, NULL }
#endif
		
/* SECURE SOCKET IMPLEMENTATION 
 * 
 *   TRANSMIT:
 *
 *      When the user sends a packet via send() system call
 *      the wanpipe_sendmsg() function is executed.  
 *      
 *      Each packet is enqueud into sk->write_queue transmit
 *      queue. When the packet is enqueued, a delayed transmit
 *      timer is triggerd which acts as a Bottom Half hander. 
 *
 *      wanpipe_delay_transmit() function (BH), dequeues packets
 *      from the sk->write_queue transmit queue and sends it 
 *      to the deriver via dev->hard_start_xmit(skb, dev) function.  
 *      Note, this function is actual a function pointer of if_send()
 *      routine in the wanpipe driver.
 *
 *      X25API GUARANTEED DELIVERY:
 *
 *         In order to provide 100% guaranteed packet delivery, 
 *         an atomic 'packet_sent' counter is implemented.  Counter 
 *         is incremented for each packet enqueued 
 *         into sk->write_queue.  Counter is decremented each
 *         time wanpipe_delayed_transmit() function successfuly 
 *         passes the packet to the driver. Before each send(), a poll
 *         routine checks the sock resources The maximum value of
 *         packet sent counter is 1, thus if one packet is queued, the
 *         application will block untill that packet is passed to the
 *         driver.
 *
 *   RECEIVE:
 *
 *      Wanpipe device drivers call the socket bottom half
 *      function, wanpipe_rcv() to queue the incoming packets
 *      into an AF_WANPIPE socket queue.  Based on wanpipe_rcv()
 *      return code, the driver knows whether the packet was
 *      sucessfully queued.  If the socket queue is full, 
 *      protocol flow control is used by the driver, if any, 
 *      to slow down the traffic untill the sock queue is free.
 *
 *      Every time a packet arrives into a socket queue the 
 *      socket wakes up processes which are waiting to receive
 *      data.
 *
 *      If the socket queue is full, the driver sets a block
 *      bit which signals the socket to kick the wanpipe driver
 *      bottom half hander when the socket queue is partialy
 *      empty. wanpipe_recvmsg() function performs this action.
 * 
 *      In case of x25api, packets will never be dropped, since
 *      flow control is available. 
 *      
 *      In case of streaming protocols like CHDLC, packets will 
 *      be dropped but the statistics will be generated. 
 */


/* The code below is used to test memory leaks. It prints out
 * a message every time kmalloc and kfree system calls get executed.
 * If the calls match there is no leak :)
 */

/***********FOR DEBUGGING PURPOSES*********************************************
#define KMEM_SAFETYZONE 8

static void * dbg_kmalloc(unsigned int size, int prio, int line) {
	void * v = kmalloc(size,prio);
	printk(KERN_INFO "line %d  kmalloc(%d,%d) = %p\n",line,size,prio,v);
	return v;
}
static void dbg_kfree(void * v, int line) {
	printk(KERN_INFO "line %d  kfree(%p)\n",line,v);
	kfree(v);
}

#define kmalloc(x,y) dbg_kmalloc(x,y,__LINE__)
#define kfree(x) dbg_kfree(x,__LINE__)
******************************************************************************/


/* List of all wanpipe sockets. */
struct sock * wanpipe_sklist = NULL;
static rwlock_t wanpipe_sklist_lock = RW_LOCK_UNLOCKED;

atomic_t wanpipe_socks_nr;
static unsigned long wanpipe_tx_critical=0;

#if 0
/* Private wanpipe socket structures. */
struct wanpipe_opt
{
	void   *mbox;		/* Mail box  */
	void   *card; 		/* Card bouded to */
	netdevice_t *dev;	/* Bounded device */
	unsigned short lcn;	/* Binded LCN */
	unsigned char  svc;	/* 0=pvc, 1=svc */
	unsigned char  timer;   /* flag for delayed transmit*/	
	struct timer_list tx_timer;
	unsigned poll_cnt;
	unsigned char force;	/* Used to force sock release */
	atomic_t packet_sent;   
};
#endif

static int sk_count=0;
extern struct proto_ops wanpipe_ops;
static unsigned long find_free_critical=0;

static void wanpipe_unlink_driver (struct sock *);
static void wanpipe_link_driver (netdevice_t *,struct sock *sk);
static void wanpipe_wakeup_driver(struct sock *sk);
static int execute_command(struct sock *, unsigned char, unsigned int);
static int check_dev (netdevice_t *, sdla_t *);
netdevice_t * wanpipe_find_free_dev (sdla_t *);
static void wanpipe_unlink_card (struct sock *);
static int wanpipe_link_card (struct sock *);
static struct sock *wanpipe_make_new(struct sock *);
static struct sock *wanpipe_alloc_socket(void);
static inline int get_atomic_device (netdevice_t *);
static int wanpipe_exec_cmd(struct sock *, int, unsigned int);
static int get_ioctl_cmd (struct sock *, void *);
static int set_ioctl_cmd (struct sock *, void *);
static void release_device (netdevice_t *);
static void wanpipe_kill_sock_timer (unsigned long data);
static void wanpipe_kill_sock_irq (struct sock *);
static void wanpipe_kill_sock_accept (struct sock *);
static int wanpipe_do_bind(struct sock *, netdevice_t *, int);
struct sock * get_newsk_from_skb (struct sk_buff *);
static int wanpipe_debug (struct sock *, void *);
static void wanpipe_delayed_transmit (unsigned long data);
static void release_driver(struct sock *);
static void start_cleanup_timer (struct sock *);
static void check_write_queue(struct sock *);
static int check_driver_busy (struct sock *);

/*============================================================
 * wanpipe_rcv
 *
 *	Wanpipe socket bottom half handler.  This function
 *      is called by the WANPIPE device drivers to queue a
 *      incomming packet into the socket receive queue. 
 *      Once the packet is queued, all processes waiting to 
 *      read are woken up.
 *
 *      During socket bind, this function is bounded into
 *      WANPIPE driver private.
 *===========================================================*/

static int wanpipe_rcv(struct sk_buff *skb, netdevice_t *dev,  struct sock *sk)
{
	struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)skb->cb;
	wanpipe_common_t *chan = dev->priv;
	/*
	 *	When we registered the protocol we saved the socket in the data
	 *	field for just this event.
	 */

	skb->dev = dev;

	sll->sll_family = AF_WANPIPE;
	sll->sll_hatype = dev->type;
	sll->sll_protocol = skb->protocol;
	sll->sll_pkttype = skb->pkt_type;
	sll->sll_ifindex = dev->ifindex;
	sll->sll_halen = 0;

	if (dev->hard_header_parse)
		sll->sll_halen = dev->hard_header_parse(skb, sll->sll_addr);

	/* 
	 * WAN_PACKET_DATA : Data which should be passed up the receive queue.
         * WAN_PACKET_ASYC : Asynchronous data like place call, which should
         *                   be passed up the listening sock.
         * WAN_PACKET_ERR  : Asynchronous data like clear call or restart 
         *                   which should go into an error queue.
         */
	switch (skb->pkt_type){

		case WAN_PACKET_DATA:
			if (sock_queue_rcv_skb(sk,skb)<0){
				return -ENOMEM;
			}
			break;
		case WAN_PACKET_CMD:
			sk->state = chan->state;
			/* Bug fix: update Mar6. 
                         * Do not set the sock lcn number here, since
         		 * cmd is not guaranteed to be executed on the
                         * board, thus Lcn could be wrong */
			sk->data_ready(sk,skb->len);
			kfree_skb(skb);
			break;
		case WAN_PACKET_ERR:
			sk->state = chan->state;
			if (sock_queue_err_skb(sk,skb)<0){
				return -ENOMEM;
			}
			break;
		default:
			printk(KERN_INFO "wansock: BH Illegal Packet Type Dropping\n");
			kfree_skb(skb); 
			break;
	}

//??????????????????????
//	if (sk->state == WANSOCK_DISCONNECTED){
//		if (sk->zapped){
//			//printk(KERN_INFO "wansock: Disconnected, killing early\n");
//			wanpipe_unlink_driver(sk);
//			sk->bound_dev_if = 0;
//		}
//	}

	return 0;
}

/*============================================================
 * wanpipe_listen_rcv
 *
 *	Wanpipe LISTEN socket bottom half handler.  This function
 *      is called by the WANPIPE device drivers to queue an
 *      incomming call into the socket listening queue. 
 *      Once the packet is queued, the waiting accept() process 
 *      is woken up.
 *
 *      During socket bind, this function is bounded into
 *      WANPIPE driver private. 
 * 
 *      IMPORTANT NOTE:
 *          The accept call() is waiting for an skb packet
 *          which contains a pointer to a device structure.
 *
 *          When we do a bind to a device structre, we 
 *          bind a newly created socket into "chan->sk".  Thus, 
 *          when accept receives the skb packet, it will know 
 *          from which dev it came form, and in turn it will know
 *          the address of the new sock.
 *
 *  	NOTE: This function gets called from driver ISR.
 *===========================================================*/

static int wanpipe_listen_rcv (struct sk_buff *skb,  struct sock *sk)
{

	struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)skb->cb;
	struct sock *newsk;
	netdevice_t *dev; 
	sdla_t *card;
	mbox_cmd_t *mbox_ptr;
	wanpipe_common_t *chan;

	/* Find a free device, if none found, all svc's are busy 
         */

	card = (sdla_t*)sk->protinfo.af_wanpipe->card;
	if (!card){
		printk(KERN_INFO "wansock: LISTEN ERROR, No Card\n");
		return -ENODEV;
	}
	
	dev = wanpipe_find_free_dev(card);
	if (!dev){
		printk(KERN_INFO "wansock: LISTEN ERROR, No Free Device\n");
		return -ENODEV;
	}

	chan=dev->priv;	
	chan->state = WANSOCK_CONNECTING;

	/* Allocate a new sock, which accept will bind
         * and pass up to the user 
	 */
	if ((newsk = wanpipe_make_new(sk)) == NULL){
		release_device(dev);
		return -ENOMEM;
	}


	/* Initialize the new sock structure 
	 */
	newsk->bound_dev_if = dev->ifindex;
	newsk->protinfo.af_wanpipe->card = sk->protinfo.af_wanpipe->card;

	/* Insert the sock into the main wanpipe
         * sock list.
         */
	atomic_inc(&wanpipe_socks_nr);

	/* Allocate and fill in the new Mail Box. Then
         * bind the mail box to the sock. It will be 
         * used by the ioctl call to read call information
         * and to execute commands. 
         */	
	if ((mbox_ptr = kmalloc(sizeof(mbox_cmd_t), GFP_ATOMIC)) == NULL) {
		wanpipe_kill_sock_irq (newsk);
		release_device(dev);		
		return -ENOMEM;
	}
	memset(mbox_ptr, 0, sizeof(mbox_cmd_t));
	memcpy(mbox_ptr,skb->data,skb->len);

	/* Register the lcn on which incoming call came
         * from. Thus, if we have to clear it, we know
         * whic lcn to clear 
	 */ 

	newsk->protinfo.af_wanpipe->lcn = mbox_ptr->cmd.lcn;
	newsk->protinfo.af_wanpipe->mbox = (void *)mbox_ptr;

	DBG_PRINTK(KERN_INFO "NEWSOCK : Device %s, bind to lcn %i\n",
			dev->name,mbox_ptr->cmd.lcn);

	chan->lcn = mbox_ptr->cmd.lcn;
	card->u.x.svc_to_dev_map[(chan->lcn%MAX_X25_LCN)] = dev;

	newsk->zapped=0;
	newsk->num = htons(X25_PROT);

	if (wanpipe_do_bind(newsk,dev,newsk->num)){
		wanpipe_kill_sock_irq (newsk);
		release_device(dev);
		return -EINVAL;
	}
	newsk->state = WANSOCK_CONNECTING;


	/* Fill in the standard sock address info */

	sll->sll_family = AF_WANPIPE;
	sll->sll_hatype = dev->type;
	sll->sll_protocol = skb->protocol;
	sll->sll_pkttype = skb->pkt_type;
	sll->sll_ifindex = dev->ifindex;
	sll->sll_halen = 0;

	skb->dev = dev;
	sk->ack_backlog++;

	/* We must do this manually, since the sock_queue_rcv_skb()
	 * function sets the skb->dev to NULL.  However, we use
	 * the dev field in the accept function.*/ 
	if (atomic_read(&sk->rmem_alloc) + skb->truesize >= 
			(unsigned)sk->rcvbuf){

         	wanpipe_unlink_driver(newsk);
		wanpipe_kill_sock_irq (newsk);
		--sk->ack_backlog;
		return -ENOMEM;
	}	

	skb_set_owner_r(skb, sk);
	skb_queue_tail(&sk->receive_queue, skb);
	sk->data_ready(sk,skb->len);
	
	return 0;
}



/*============================================================
 * wanpipe_make_new
 *
 *	Create a new sock, and allocate a wanpipe private
 *      structure to it. Also, copy the important data
 *      from the original sock to the new sock.
 *
 *      This function is used by wanpipe_listen_rcv() listen
 *      bottom half handler.  A copy of the listening sock
 *      is created using this function.
 *
 *===========================================================*/

static struct sock *wanpipe_make_new(struct sock *osk)
{
	struct sock *sk;

	if (osk->type != SOCK_RAW)
		return NULL;

	if ((sk = wanpipe_alloc_socket()) == NULL)
		return NULL;

	sk->type        = osk->type;
	sk->socket      = osk->socket;
	sk->priority    = osk->priority;
	sk->protocol    = osk->protocol;
	sk->num		= osk->num;
	sk->rcvbuf      = osk->rcvbuf;
	sk->sndbuf      = osk->sndbuf;
	sk->debug       = osk->debug;
	sk->state       = WANSOCK_CONNECTING;
	sk->sleep       = osk->sleep;

	return sk;
}

/*============================================================
 * wanpipe_make_new
 *
 *	Allocate memory for the a new sock, and sock
 *      private data.  
 *	
 *	Increment the module use count.
 *       	
 *      This function is used by wanpipe_create() and 
 *      wanpipe_make_new() functions. 
 *
 *===========================================================*/

static struct sock *wanpipe_alloc_socket(void)
{
	struct sock *sk;
	struct wanpipe_opt *wan_opt;

	if ((sk = sk_alloc(PF_WANPIPE, GFP_ATOMIC, 1)) == NULL)
		return NULL;

	if ((wan_opt = kmalloc(sizeof(struct wanpipe_opt), GFP_ATOMIC)) == NULL) {