Linux/NetDriver/sheep_net.c

/*
 *  sheep_net.c - Linux driver for SheepShaver/Basilisk II networking (access to raw Ethernet packets)
 *
 *  sheep_net (C) 1999-2004 Mar"c" Hellwig and Christian Bauer
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* determine whether to use checksummed versions of kernel symbols */
#include <linux/config.h>

#if defined(CONFIG_MODVERSIONS) && !defined(MODVERSIONS)
#define MODVERSIONS
#endif

#if defined(MODVERSIONS)
#include <linux/modversions.h>
#endif

/* modversions.h redefines kernel symbols.  Now include other headers */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/version.h>

#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <net/arp.h>
#include <net/ip.h>
#include <linux/in.h>
#include <linux/wait.h>

MODULE_AUTHOR("Christian Bauer");
MODULE_DESCRIPTION("Pseudo ethernet device for emulators");

/* Compatibility glue */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
#define LINUX_26
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
#define LINUX_24
#else
#define net_device device
typedef struct wait_queue *wait_queue_head_t;
#define init_waitqueue_head(x) *(x)=NULL
#endif

#ifdef LINUX_26
#define compat_sk_alloc(a,b,c)  sk_alloc( (a), (b), (c), NULL )
#define skt_set_dead(skt)               do {} while(0)
#define wmem_alloc                              sk_wmem_alloc
#else
#define compat_sk_alloc                 sk_alloc
#define skt_set_dead(skt)               (skt)->dead = 1
#endif

#define DEBUG 0

#define bug printk
#if DEBUG
#define D(x) (x);
#else
#define D(x) ;
#endif


/* Constants */
#define SHEEP_NET_MINOR 198             /* Driver minor number */
#define MAX_QUEUE 32                    /* Maximum number of packets in queue */
#define PROT_MAGIC 1520                 /* Our "magic" protocol type */

#define ETH_ADDR_MULTICAST 0x1
#define ETH_ADDR_LOCALLY_DEFINED 0x02

#define SIOC_MOL_GET_IPFILTER SIOCDEVPRIVATE
#define SIOC_MOL_SET_IPFILTER (SIOCDEVPRIVATE + 1)

/* Prototypes */
static int sheep_net_open(struct inode *inode, struct file *f);
static int sheep_net_release(struct inode *inode, struct file *f);
static ssize_t sheep_net_read(struct file *f, char *buf, size_t count, loff_t *off);
static ssize_t sheep_net_write(struct file *f, const char *buf, size_t count, loff_t *off);
static unsigned int sheep_net_poll(struct file *f, struct poll_table_struct *wait);
static int sheep_net_ioctl(struct inode *inode, struct file *f, unsigned int code, unsigned long arg);
static int sheep_net_receiver(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt);


/*
 *  Driver private variables
 */

struct SheepVars {
        /* IMPORTANT: the packet_type struct must go first. It no longer
           (2.6) contains * a data field so we typecast to get the SheepVars
           struct */
        struct packet_type pt;          /* Receiver packet type */
        struct net_device *ether;       /* The Ethernet device we're attached to */
        struct sock *skt;                       /* Socket for communication with Ethernet card */
        struct sk_buff_head queue;      /* Receiver packet queue */
        wait_queue_head_t wait;         /* Wait queue for blocking read operations */
        u32 ipfilter;                           /* Only receive IP packets destined for this address (host byte order) */
        char eth_addr[6];                       /* Hardware address of the Ethernet card */
        char fake_addr[6];                      /* Local faked hardware address (what SheepShaver sees) */
};


/*
 *  file_operations structure - has function pointers to the
 *  various entry points for device operations
 */

static struct file_operations sheep_net_fops = {
        .owner          = THIS_MODULE,
        .read           = sheep_net_read,
        .write          = sheep_net_write,
        .poll           = sheep_net_poll,
        .ioctl          = sheep_net_ioctl,
        .open           = sheep_net_open,
        .release        = sheep_net_release,
};


/*
 *  miscdevice structure for driver initialization
 */

static struct miscdevice sheep_net_device = {
        .minor          = SHEEP_NET_MINOR,      /* minor number */
        .name           = "sheep_net",          /* name */
        .fops           = &sheep_net_fops
};


/*
 *  Initialize module
 */

int init_module(void)
{
        int ret;

        /* Register driver */
        ret = misc_register(&sheep_net_device);
        D(bug("Sheep net driver installed\n"));
        return ret;
}


/*
 *  Deinitialize module
 */

void cleanup_module(void)
{
        /* Unregister driver */
        misc_deregister(&sheep_net_device);
        D(bug("Sheep net driver removed\n"));
}


/*
 *  Driver open() function
 */

static int sheep_net_open(struct inode *inode, struct file *f)
{
        struct SheepVars *v;
        D(bug("sheep_net: open\n"));

        /* Must be opened with read permissions */
        if ((f->f_flags & O_ACCMODE) == O_WRONLY)
                return -EPERM;

        /* Allocate private variables */
        v = (struct SheepVars *)(f->private_data = kmalloc(sizeof(struct SheepVars), GFP_USER));
        if (v == NULL)
                return -ENOMEM;
        memset(v, 0, sizeof(struct SheepVars));
        skb_queue_head_init(&v->queue);
        init_waitqueue_head(&v->wait);
        v->fake_addr[0] = 0xfe;
        v->fake_addr[1] = 0xfd;
        v->fake_addr[2] = 0xde;
        v->fake_addr[3] = 0xad;
        v->fake_addr[4] = 0xbe;
        v->fake_addr[5] = 0xef;

        /* Yes, we're open */
#ifndef LINUX_26
        MOD_INC_USE_COUNT;
#endif
        return 0;
}


/*
 *  Driver release() function
 */

static int sheep_net_release(struct inode *inode, struct file *f)
{
        struct SheepVars *v = (struct SheepVars *)f->private_data;
        struct sk_buff *skb;
        D(bug("sheep_net: close\n"));

        /* Detach from Ethernet card */
        if (v->ether) {
                dev_remove_pack(&v->pt);
                sk_free(v->skt);
                v->skt = NULL;
#ifdef LINUX_24
                dev_put( v->ether );
#endif
                v->ether = NULL;
        }

        /* Empty packet queue */
        while ((skb = skb_dequeue(&v->queue)) != NULL)
                dev_kfree_skb(skb);

        /* Free private variables */
        kfree(v);

        /* Sorry, we're closed */
#ifndef LINUX_26
        MOD_DEC_USE_COUNT;
#endif
        return 0;
}


/*
 *  Check whether an Ethernet address is the local (attached) one or
 *  the fake one
 */

static inline int is_local_addr(struct SheepVars *v, void *a)
{
        return memcmp(a, v->eth_addr, 6) == 0;
}

static inline int is_fake_addr(struct SheepVars *v, void *a)
{
        return memcmp(a, v->fake_addr, 6) == 0;
}


/* 
 * Outgoing packet. Replace the fake enet addr with the real local one.
 */

static inline void do_demasq(struct SheepVars *v, u8 *p)
{
        memcpy(p, v->eth_addr, 6);
}

static void demasquerade(struct SheepVars *v, struct sk_buff *skb)
{
        u8 *p = skb->mac.raw;
        int proto = (p[12] << 8) | p[13];
        
        do_demasq(v, p + 6); /* source address */

        /* Need to fix ARP packets */
        if (proto == ETH_P_ARP) {
                if (is_fake_addr(v, p + 14 + 8)) /* sender HW-addr */
                        do_demasq(v, p + 14 + 8);
        }

        /* ...and AARPs (snap code: 0x00,0x00,0x00,0x80,0xF3) */
        if (p[17] == 0 && p[18] == 0 && p[19] == 0 && p[20] == 0x80 && p[21] == 0xf3) {
                /* XXX: we should perhaps look for the 802 frame too */
                if (is_fake_addr(v, p + 30))
                        do_demasq(v, p + 30); /* sender HW-addr */
        }
}


/*
 * Incoming packet. Replace the local enet addr with the fake one.
 */

static inline void do_masq(struct SheepVars *v, u8 *p)
{
        memcpy(p, v->fake_addr, 6);
}

static void masquerade(struct SheepVars *v, struct sk_buff *skb)
{
        u8 *p = skb->mac.raw;
        if (!(p[0] & ETH_ADDR_MULTICAST))
                do_masq(v, p); /* destination address */

        /* XXX: reverse ARP might need to be fixed */
}


/*
 *  Driver read() function
 */

static ssize_t sheep_net_read(struct file *f, char *buf, size_t count, loff_t *off)
{
        struct SheepVars *v = (struct SheepVars *)f->private_data;
        struct sk_buff *skb;

        D(bug("sheep_net: read\n"));

        for (;;) {

                /* Get next packet from queue */
                skb = skb_dequeue(&v->queue);
                if (skb != NULL || (f->f_flags & O_NONBLOCK))
                        break;

                /* No packet in queue and in blocking mode, so block */
                interruptible_sleep_on(&v->wait);

                /* Signal received? Then bail out */
                if (signal_pending(current))
                        return -EINTR;
        }
        if (skb == NULL)
                return -EAGAIN;

        /* Pass packet to caller */
        if (count > skb->len)
                count = skb->len;
        if (copy_to_user(buf, skb->data, count))
                count = -EFAULT;
        dev_kfree_skb(skb);
        return count;
}


/*
 *  Driver write() function
 */

static ssize_t sheep_net_write(struct file *f, const char *buf, size_t count, loff_t *off)
{
        struct SheepVars *v = (struct SheepVars *)f->private_data;
        struct sk_buff *skb;
        char *p;
        D(bug("sheep_net: write\n"));

        /* Check packet size */
        if (count < sizeof(struct ethhdr))
                return -EINVAL;
        if (count > 1514) {
                printk("sheep_net_write: packet size > 1514\n");
                count = 1514;
        }

        /* Interface active? */
        if (v->ether == NULL)
                return count;

        /* Allocate buffer for packet */
        skb = dev_alloc_skb(count);
        if (skb == NULL)
                return -ENOBUFS;

        /* Stuff packet in buffer */
        p = skb_put(skb, count);
        if (copy_from_user(p, buf, count)) {
                kfree_skb(skb);
                return -EFAULT;
        }

        /* Transmit packet */
        atomic_add(skb->truesize, &v->skt->wmem_alloc);
        skb->sk = v->skt;
        skb->dev = v->ether;
        skb->priority = 0;
        skb->nh.raw = skb->h.raw = skb->data + v->ether->hard_header_len;
        skb->mac.raw = skb->data;

        /* Base the IP-filtering on the IP address in any outgoing ARP packets */
        if (skb->mac.ethernet->h_proto == htons(ETH_P_ARP)) {
                u8 *p = &skb->data[14+14];      /* source IP address */
                u32 ip = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
                if (ip != v->ipfilter) {
                        v->ipfilter = ip;
                        printk("sheep_net: ipfilter set to %d.%d.%d.%d\n", (ip >> 24) & 0xff, (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
                }
        }

        /* Is this packet addressed solely to the local host? */
        if (is_local_addr(v, skb->data) && !(skb->data[0] & ETH_ADDR_MULTICAST)) {
                skb->protocol = eth_type_trans(skb, v->ether);
                netif_rx(skb);
                return count;
        }
        if (skb->data[0] & ETH_ADDR_MULTICAST) {
                /* We can't clone the skb since we will manipulate the data below */
                struct sk_buff *lskb = skb_copy(skb, GFP_ATOMIC);
                if (lskb) {
                        lskb->protocol = eth_type_trans(lskb, v->ether);
                        netif_rx(lskb);
                }
        }

        /* Outgoing packet (will be on the net) */
        demasquerade(v, skb);

        skb->protocol = PROT_MAGIC;     /* Magic value (we can recognize the packet in sheep_net_receiver) */
        dev_queue_xmit(skb);
        return count;
}


/*
 *  Driver poll() function
 */

static unsigned int sheep_net_poll(struct file *f, struct poll_table_struct *wait)
{
        struct SheepVars *v = (struct SheepVars *)f->private_data;
        D(bug("sheep_net: poll\n"));

        /* Packets in queue? Then return */
        if (!skb_queue_empty(&v->queue))
                return POLLIN | POLLRDNORM;

        /* Otherwise wait for packet */
        poll_wait(f, &v->wait, wait);
        if (!skb_queue_empty(&v->queue))
                return POLLIN | POLLRDNORM;
        else
                return 0;
}


/*
 *  Driver ioctl() function
 */

static int sheep_net_ioctl(struct inode *inode, struct file *f, unsigned int code, unsigned long arg)
{
        struct SheepVars *v = (struct SheepVars *)f->private_data;
        D(bug("sheep_net: ioctl %04x\n", code));

        switch (code) {

                /* Attach to Ethernet card
                   arg: pointer to name of Ethernet device (char[20]) */
                case SIOCSIFLINK: {
                        char name[20];
                        int err;

                        /* Already attached? */
                        if (v->ether)
                                return -EBUSY;

                        /* Get Ethernet card name */
                        if (copy_from_user(name, (void *)arg, 20))
                                return -EFAULT;
                        name[19] = 0;

                        /* Find card */
#ifdef LINUX_24
                        v->ether = dev_get_by_name(name);
#else
                        dev_lock_list();
                        v->ether = dev_get(name);
#endif
                        if (v->ether == NULL) {
                                err = -ENODEV;
                                goto error;
                        }

                        /* Is it Ethernet? */
                        if (v->ether->type != ARPHRD_ETHER) {
                                err = -EINVAL;
                                goto error;
                        }

                        /* Remember the card's hardware address */
                        memcpy(v->eth_addr, v->ether->dev_addr, 6);

                        /* Allocate socket */
                        v->skt = compat_sk_alloc(0, GFP_USER, 1);
                        if (v->skt == NULL) {
                                err = -ENOMEM;
                                goto error;
                        }
                        skt_set_dead(v->skt->dead);

                        /* Attach packet handler */
                        v->pt.type = htons(ETH_P_ALL);
                        v->pt.dev = v->ether;
                        v->pt.func = sheep_net_receiver;
                        dev_add_pack(&v->pt);
#ifndef LINUX_24
                        dev_unlock_list();
#endif
                        return 0;

error:
#ifdef LINUX_24
                        if (v->ether)
                                dev_put(v->ether);
#else
                        dev_unlock_list();
#endif
                        v->ether = NULL;
                        return err;
                }

                /* Get hardware address of the sheep_net module
                   arg: pointer to buffer (6 bytes) to store address */
                case SIOCGIFADDR:
                        if (copy_to_user((void *)arg, v->fake_addr, 6))
                                return -EFAULT;
                        return 0;

                /* Set the hardware address of the sheep_net module
                   arg: pointer to new address (6 bytes) */
                case SIOCSIFADDR:
                        if (copy_from_user(v->fake_addr, (void*)arg, 6))
                                return -EFAULT;
                        return 0;

                /* Add multicast address
                   arg: pointer to address (6 bytes) */
                case SIOCADDMULTI: {
                        char addr[6];
                        if (v->ether == NULL)
                                return -ENODEV;
                        if (copy_from_user(addr, (void *)arg, 6))
                                return -EFAULT;
                        return dev_mc_add(v->ether, addr, 6, 0);
                }

                /* Remove multicast address
                   arg: pointer to address (6 bytes) */
                case SIOCDELMULTI: {
                        char addr[6];
                        if (v->ether == NULL)
                                return -ENODEV;
                        if (copy_from_user(addr, (void *)arg, 6))
                                return -EFAULT;
                        return dev_mc_delete(v->ether, addr, 6, 0);
                }

                /* Return size of first packet in queue */
                case FIONREAD: {
                        int count = 0;
                        struct sk_buff *skb;
#ifdef LINUX_24
                        unsigned long flags;
                        spin_lock_irqsave(&v->queue.lock, flags);
#else
                        cli();
#endif
                        skb = skb_peek(&v->queue);
                        if (skb)
                                count = skb->len;
#ifdef LINUX_24
                        spin_unlock_irqrestore(&v->queue.lock, flags);
#else
                        sti();
#endif
                        return put_user(count, (int *)arg);
                }

                case SIOC_MOL_GET_IPFILTER:
                        return put_user(v->ipfilter, (int *)arg);

                case SIOC_MOL_SET_IPFILTER:
                        v->ipfilter = arg;
                        return 0;

                default:
                        return -ENOIOCTLCMD;
        }
}


/*
 *  Packet receiver function
 */

static int sheep_net_receiver(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
{
        struct SheepVars *v = (struct SheepVars *)pt;
        struct sk_buff *skb2;
        int fake;
        int multicast;
        D(bug("sheep_net: packet received\n"));

        multicast = (skb->mac.ethernet->h_dest[0] & ETH_ADDR_MULTICAST);
        fake = is_fake_addr(v, &skb->mac.ethernet->h_dest);

        /* Packet sent by us? Then discard */
        if (is_fake_addr(v, &skb->mac.ethernet->h_source) || skb->protocol == PROT_MAGIC)
                goto drop;

        /* If the packet is not meant for this host, discard it */
        if (!is_local_addr(v, &skb->mac.ethernet->h_dest) && !multicast && !fake)
                goto drop;

        /* Discard packets if queue gets too full */
        if (skb_queue_len(&v->queue) > MAX_QUEUE)
                goto drop;

        /* Apply any filters here (if fake is true, then we *know* we want this packet) */
        if (!fake) {
                if ((skb->protocol == htons(ETH_P_IP))
                 && (!v->ipfilter || (ntohl(skb->h.ipiph->daddr) != v->ipfilter && !multicast)))
                        goto drop;
        }

        /* Masquerade (we are typically a clone - best to make a real copy) */
        skb2 = skb_copy(skb, GFP_ATOMIC);
        if (!skb2)
                goto drop;
        kfree_skb(skb);
        skb = skb2;
        masquerade(v, skb);

        /* We also want the Ethernet header */
        skb_push(skb, skb->data - skb->mac.raw);

        /* Enqueue packet */
        skb_queue_tail(&v->queue, skb);

        /* Unblock blocked read */
        wake_up(&v->wait);
        return 0;

drop:
        kfree_skb(skb);
        return 0;
}

MODULE_LICENSE("GPL");
Revision:	1.12
Committed:	2004-12-18T17:49:12Z (19 years, 8 months ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
Changes since 1.11:	+38 -23 lines
Log Message:	support for kernel 2.6 (from MOL)
#	User	Rev	Content
1	cebix	1.1	/*
2			* sheep_net.c - Linux driver for SheepShaver/Basilisk II networking (access to raw Ethernet packets)
3			*
4	cebix	1.11	* sheep_net (C) 1999-2004 Mar"c" Hellwig and Christian Bauer
5	cebix	1.1	*
6			* This program is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19			*/
20
21	cebix	1.10	/* determine whether to use checksummed versions of kernel symbols */
22			#include <linux/config.h>
23	cebix	1.9
24	cebix	1.10	#if defined(CONFIG_MODVERSIONS) && !defined(MODVERSIONS)
25			#define MODVERSIONS
26	cebix	1.9	#endif
27
28	cebix	1.10	#if defined(MODVERSIONS)
29	cebix	1.9	#include <linux/modversions.h>
30			#endif
31
32			/* modversions.h redefines kernel symbols. Now include other headers */
33			#include <linux/kernel.h>
34			#include <linux/module.h>
35	cebix	1.10	#include <linux/version.h>
36	cebix	1.9
37	cebix	1.10	#include <linux/types.h>
38	cebix	1.1	#include <linux/miscdevice.h>
39			#include <linux/netdevice.h>
40			#include <linux/etherdevice.h>
41			#include <linux/if_ether.h>
42			#include <linux/if_arp.h>
43	cebix	1.7	#include <linux/fs.h>
44	cebix	1.1	#include <linux/poll.h>
45			#include <linux/init.h>
46			#include <net/sock.h>
47	cebix	1.7	#include <asm/uaccess.h>
48	gbeauche	1.12	#include <asm/ioctls.h>
49	cebix	1.4	#include <net/arp.h>
50			#include <net/ip.h>
51	cebix	1.7	#include <linux/in.h>
52			#include <linux/wait.h>
53	cebix	1.1
54	cebix	1.5	MODULE_AUTHOR("Christian Bauer");
55			MODULE_DESCRIPTION("Pseudo ethernet device for emulators");
56
57	cebix	1.4	/* Compatibility glue */
58	gbeauche	1.12	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
59			#define LINUX_26
60			#endif
61	cebix	1.4	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
62			#define LINUX_24
63			#else
64			#define net_device device
65			typedef struct wait_queue *wait_queue_head_t;
66			#define init_waitqueue_head(x) *(x)=NULL
67			#endif
68
69	gbeauche	1.12	#ifdef LINUX_26
70			#define compat_sk_alloc(a,b,c) sk_alloc( (a), (b), (c), NULL )
71			#define skt_set_dead(skt) do {} while(0)
72			#define wmem_alloc sk_wmem_alloc
73			#else
74			#define compat_sk_alloc sk_alloc
75			#define skt_set_dead(skt) (skt)->dead = 1
76			#endif
77
78	cebix	1.1	#define DEBUG 0
79
80			#define bug printk
81			#if DEBUG
82			#define D(x) (x);
83			#else
84			#define D(x) ;
85			#endif
86
87
88	cebix	1.4	/* Constants */
89			#define SHEEP_NET_MINOR 198 /* Driver minor number */
90			#define MAX_QUEUE 32 /* Maximum number of packets in queue */
91			#define PROT_MAGIC 1520 /* Our "magic" protocol type */
92	cebix	1.1
93	cebix	1.4	#define ETH_ADDR_MULTICAST 0x1
94	cebix	1.7	#define ETH_ADDR_LOCALLY_DEFINED 0x02
95	cebix	1.4
96			#define SIOC_MOL_GET_IPFILTER SIOCDEVPRIVATE
97			#define SIOC_MOL_SET_IPFILTER (SIOCDEVPRIVATE + 1)
98
99			/* Prototypes */
100	cebix	1.1	static int sheep_net_open(struct inode inode, struct file f);
101			static int sheep_net_release(struct inode inode, struct file f);
102			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off);
103			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off);
104			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait);
105			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg);
106	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt);
107	cebix	1.1
108
109			/*
110			* Driver private variables
111			*/
112
113			struct SheepVars {
114	gbeauche	1.12	/* IMPORTANT: the packet_type struct must go first. It no longer
115			(2.6) contains * a data field so we typecast to get the SheepVars
116			struct */
117			struct packet_type pt; /* Receiver packet type */
118	cebix	1.4	struct net_device ether; / The Ethernet device we're attached to */
119			struct sock skt; / Socket for communication with Ethernet card */
120			struct sk_buff_head queue; /* Receiver packet queue */
121			wait_queue_head_t wait; /* Wait queue for blocking read operations */
122			u32 ipfilter; /* Only receive IP packets destined for this address (host byte order) */
123			char eth_addr[6]; /* Hardware address of the Ethernet card */
124			char fake_addr[6]; /* Local faked hardware address (what SheepShaver sees) */
125	cebix	1.1	};
126
127
128			/*
129			* file_operations structure - has function pointers to the
130			* various entry points for device operations
131			*/
132
133			static struct file_operations sheep_net_fops = {
134	gbeauche	1.12	.owner = THIS_MODULE,
135			.read = sheep_net_read,
136			.write = sheep_net_write,
137			.poll = sheep_net_poll,
138			.ioctl = sheep_net_ioctl,
139			.open = sheep_net_open,
140			.release = sheep_net_release,
141	cebix	1.1	};
142
143
144			/*
145			* miscdevice structure for driver initialization
146			*/
147
148			static struct miscdevice sheep_net_device = {
149	gbeauche	1.12	.minor = SHEEP_NET_MINOR, /* minor number */
150			.name = "sheep_net", /* name */
151			.fops = &sheep_net_fops
152	cebix	1.1	};
153
154
155			/*
156			* Initialize module
157			*/
158
159			int init_module(void)
160			{
161			int ret;
162
163	cebix	1.4	/* Register driver */
164	cebix	1.1	ret = misc_register(&sheep_net_device);
165			D(bug("Sheep net driver installed\n"));
166			return ret;
167			}
168
169
170			/*
171			* Deinitialize module
172			*/
173
174	gbeauche	1.12	void cleanup_module(void)
175	cebix	1.1	{
176	cebix	1.4	/* Unregister driver */
177	gbeauche	1.12	misc_deregister(&sheep_net_device);
178	cebix	1.1	D(bug("Sheep net driver removed\n"));
179			}
180
181
182			/*
183			* Driver open() function
184			*/
185
186			static int sheep_net_open(struct inode inode, struct file f)
187			{
188			struct SheepVars *v;
189			D(bug("sheep_net: open\n"));
190
191	cebix	1.4	/* Must be opened with read permissions */
192	cebix	1.1	if ((f->f_flags & O_ACCMODE) == O_WRONLY)
193			return -EPERM;
194
195	cebix	1.4	/* Allocate private variables */
196	gbeauche	1.12	v = (struct SheepVars *)(f->private_data = kmalloc(sizeof(struct SheepVars), GFP_USER));
197	cebix	1.1	if (v == NULL)
198			return -ENOMEM;
199			memset(v, 0, sizeof(struct SheepVars));
200			skb_queue_head_init(&v->queue);
201	cebix	1.4	init_waitqueue_head(&v->wait);
202			v->fake_addr[0] = 0xfe;
203			v->fake_addr[1] = 0xfd;
204			v->fake_addr[2] = 0xde;
205			v->fake_addr[3] = 0xad;
206			v->fake_addr[4] = 0xbe;
207			v->fake_addr[5] = 0xef;
208	cebix	1.1
209	cebix	1.4	/* Yes, we're open */
210	gbeauche	1.12	#ifndef LINUX_26
211	cebix	1.1	MOD_INC_USE_COUNT;
212	gbeauche	1.12	#endif
213	cebix	1.1	return 0;
214			}
215
216
217			/*
218			* Driver release() function
219			*/
220
221			static int sheep_net_release(struct inode inode, struct file f)
222			{
223			struct SheepVars v = (struct SheepVars )f->private_data;
224			struct sk_buff *skb;
225			D(bug("sheep_net: close\n"));
226
227	cebix	1.4	/* Detach from Ethernet card */
228	cebix	1.1	if (v->ether) {
229			dev_remove_pack(&v->pt);
230			sk_free(v->skt);
231			v->skt = NULL;
232	cebix	1.4	#ifdef LINUX_24
233			dev_put( v->ether );
234			#endif
235	cebix	1.1	v->ether = NULL;
236			}
237
238	cebix	1.4	/* Empty packet queue */
239	cebix	1.1	while ((skb = skb_dequeue(&v->queue)) != NULL)
240			dev_kfree_skb(skb);
241
242	cebix	1.4	/* Free private variables */
243	cebix	1.1	kfree(v);
244
245	cebix	1.4	/* Sorry, we're closed */
246	gbeauche	1.12	#ifndef LINUX_26
247	cebix	1.1	MOD_DEC_USE_COUNT;
248	gbeauche	1.12	#endif
249	cebix	1.1	return 0;
250			}
251
252
253			/*
254	cebix	1.4	* Check whether an Ethernet address is the local (attached) one or
255			* the fake one
256			*/
257
258			static inline int is_local_addr(struct SheepVars v, void a)
259			{
260			return memcmp(a, v->eth_addr, 6) == 0;
261			}
262
263			static inline int is_fake_addr(struct SheepVars v, void a)
264			{
265			return memcmp(a, v->fake_addr, 6) == 0;
266			}
267
268
269			/*
270			* Outgoing packet. Replace the fake enet addr with the real local one.
271			*/
272
273			static inline void do_demasq(struct SheepVars v, u8 p)
274			{
275			memcpy(p, v->eth_addr, 6);
276			}
277
278			static void demasquerade(struct SheepVars v, struct sk_buff skb)
279			{
280			u8 *p = skb->mac.raw;
281			int proto = (p[12] << 8) \| p[13];
282
283			do_demasq(v, p + 6); /* source address */
284
285			/* Need to fix ARP packets */
286			if (proto == ETH_P_ARP) {
287			if (is_fake_addr(v, p + 14 + 8)) /* sender HW-addr */
288			do_demasq(v, p + 14 + 8);
289			}
290
291			/* ...and AARPs (snap code: 0x00,0x00,0x00,0x80,0xF3) */
292			if (p[17] == 0 && p[18] == 0 && p[19] == 0 && p[20] == 0x80 && p[21] == 0xf3) {
293			/* XXX: we should perhaps look for the 802 frame too */
294			if (is_fake_addr(v, p + 30))
295			do_demasq(v, p + 30); /* sender HW-addr */
296			}
297			}
298
299
300			/*
301			* Incoming packet. Replace the local enet addr with the fake one.
302			*/
303
304			static inline void do_masq(struct SheepVars v, u8 p)
305			{
306			memcpy(p, v->fake_addr, 6);
307			}
308
309			static void masquerade(struct SheepVars v, struct sk_buff skb)
310			{
311			u8 *p = skb->mac.raw;
312			if (!(p[0] & ETH_ADDR_MULTICAST))
313			do_masq(v, p); /* destination address */
314
315			/* XXX: reverse ARP might need to be fixed */
316			}
317
318
319			/*
320	cebix	1.1	* Driver read() function
321			*/
322
323			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off)
324			{
325			struct SheepVars v = (struct SheepVars )f->private_data;
326			struct sk_buff *skb;
327	cebix	1.4
328	cebix	1.1	D(bug("sheep_net: read\n"));
329
330			for (;;) {
331
332	cebix	1.4	/* Get next packet from queue */
333	cebix	1.1	skb = skb_dequeue(&v->queue);
334			if (skb != NULL \|\| (f->f_flags & O_NONBLOCK))
335			break;
336
337	cebix	1.4	/* No packet in queue and in blocking mode, so block */
338	cebix	1.1	interruptible_sleep_on(&v->wait);
339
340	cebix	1.4	/* Signal received? Then bail out */
341			if (signal_pending(current))
342			return -EINTR;
343	cebix	1.1	}
344			if (skb == NULL)
345			return -EAGAIN;
346
347	cebix	1.4	/* Pass packet to caller */
348	cebix	1.1	if (count > skb->len)
349			count = skb->len;
350			if (copy_to_user(buf, skb->data, count))
351			count = -EFAULT;
352			dev_kfree_skb(skb);
353			return count;
354			}
355
356
357			/*
358			* Driver write() function
359			*/
360
361			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off)
362			{
363			struct SheepVars v = (struct SheepVars )f->private_data;
364			struct sk_buff *skb;
365			char *p;
366			D(bug("sheep_net: write\n"));
367
368	cebix	1.4	/* Check packet size */
369	cebix	1.1	if (count < sizeof(struct ethhdr))
370			return -EINVAL;
371	cebix	1.7	if (count > 1514) {
372			printk("sheep_net_write: packet size > 1514\n");
373	cebix	1.1	count = 1514;
374	cebix	1.7	}
375	cebix	1.1
376	cebix	1.4	/* Interface active? */
377	cebix	1.1	if (v->ether == NULL)
378			return count;
379
380	cebix	1.4	/* Allocate buffer for packet */
381	cebix	1.1	skb = dev_alloc_skb(count);
382			if (skb == NULL)
383			return -ENOBUFS;
384
385	cebix	1.4	/* Stuff packet in buffer */
386	cebix	1.1	p = skb_put(skb, count);
387			if (copy_from_user(p, buf, count)) {
388			kfree_skb(skb);
389			return -EFAULT;
390			}
391
392	cebix	1.4	/* Transmit packet */
393	cebix	1.1	atomic_add(skb->truesize, &v->skt->wmem_alloc);
394			skb->sk = v->skt;
395			skb->dev = v->ether;
396			skb->priority = 0;
397			skb->nh.raw = skb->h.raw = skb->data + v->ether->hard_header_len;
398	cebix	1.4	skb->mac.raw = skb->data;
399
400			/* Base the IP-filtering on the IP address in any outgoing ARP packets */
401			if (skb->mac.ethernet->h_proto == htons(ETH_P_ARP)) {
402			u8 p = &skb->data[14+14]; / source IP address */
403			u32 ip = (p[0] << 24) \| (p[1] << 16) \| (p[2] << 8) \| p[3];
404			if (ip != v->ipfilter) {
405			v->ipfilter = ip;
406			printk("sheep_net: ipfilter set to %d.%d.%d.%d\n", (ip >> 24) & 0xff, (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
407			}
408			}
409
410			/* Is this packet addressed solely to the local host? */
411			if (is_local_addr(v, skb->data) && !(skb->data[0] & ETH_ADDR_MULTICAST)) {
412			skb->protocol = eth_type_trans(skb, v->ether);
413			netif_rx(skb);
414			return count;
415			}
416			if (skb->data[0] & ETH_ADDR_MULTICAST) {
417			/* We can't clone the skb since we will manipulate the data below */
418			struct sk_buff *lskb = skb_copy(skb, GFP_ATOMIC);
419			if (lskb) {
420			lskb->protocol = eth_type_trans(lskb, v->ether);
421			netif_rx(lskb);
422			}
423			}
424
425			/* Outgoing packet (will be on the net) */
426			demasquerade(v, skb);
427
428			skb->protocol = PROT_MAGIC; /* Magic value (we can recognize the packet in sheep_net_receiver) */
429	cebix	1.1	dev_queue_xmit(skb);
430			return count;
431			}
432
433
434			/*
435			* Driver poll() function
436			*/
437
438			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait)
439			{
440			struct SheepVars v = (struct SheepVars )f->private_data;
441			D(bug("sheep_net: poll\n"));
442
443	cebix	1.4	/* Packets in queue? Then return */
444			if (!skb_queue_empty(&v->queue))
445	cebix	1.1	return POLLIN \| POLLRDNORM;
446
447	cebix	1.4	/* Otherwise wait for packet */
448	cebix	1.1	poll_wait(f, &v->wait, wait);
449	cebix	1.4	if (!skb_queue_empty(&v->queue))
450	cebix	1.1	return POLLIN \| POLLRDNORM;
451	cebix	1.4	else
452	cebix	1.1	return 0;
453			}
454
455
456			/*
457			* Driver ioctl() function
458			*/
459
460			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg)
461			{
462			struct SheepVars v = (struct SheepVars )f->private_data;
463			D(bug("sheep_net: ioctl %04x\n", code));
464
465			switch (code) {
466
467	cebix	1.4	/* Attach to Ethernet card
468	cebix	1.7	arg: pointer to name of Ethernet device (char[20]) */
469	cebix	1.1	case SIOCSIFLINK: {
470	cebix	1.7	char name[20];
471	cebix	1.4	int err;
472	cebix	1.1
473	cebix	1.4	/* Already attached? */
474	cebix	1.1	if (v->ether)
475			return -EBUSY;
476
477	cebix	1.4	/* Get Ethernet card name */
478	cebix	1.7	if (copy_from_user(name, (void *)arg, 20))
479	cebix	1.1	return -EFAULT;
480	cebix	1.7	name[19] = 0;
481	cebix	1.1
482	cebix	1.4	/* Find card */
483			#ifdef LINUX_24
484			v->ether = dev_get_by_name(name);
485			#else
486	cebix	1.1	dev_lock_list();
487			v->ether = dev_get(name);
488	cebix	1.4	#endif
489	cebix	1.1	if (v->ether == NULL) {
490	cebix	1.4	err = -ENODEV;
491			goto error;
492	cebix	1.1	}
493
494	cebix	1.4	/* Is it Ethernet? */
495	cebix	1.1	if (v->ether->type != ARPHRD_ETHER) {
496	cebix	1.4	err = -EINVAL;
497			goto error;
498	cebix	1.1	}
499
500	cebix	1.4	/* Remember the card's hardware address */
501			memcpy(v->eth_addr, v->ether->dev_addr, 6);
502
503			/* Allocate socket */
504	gbeauche	1.12	v->skt = compat_sk_alloc(0, GFP_USER, 1);
505	cebix	1.1	if (v->skt == NULL) {
506	cebix	1.4	err = -ENOMEM;
507			goto error;
508	cebix	1.1	}
509	gbeauche	1.12	skt_set_dead(v->skt->dead);
510	cebix	1.1
511	cebix	1.4	/* Attach packet handler */
512	cebix	1.1	v->pt.type = htons(ETH_P_ALL);
513			v->pt.dev = v->ether;
514			v->pt.func = sheep_net_receiver;
515			dev_add_pack(&v->pt);
516	cebix	1.4	#ifndef LINUX_24
517	cebix	1.1	dev_unlock_list();
518	cebix	1.4	#endif
519	cebix	1.1	return 0;
520	cebix	1.4
521			error:
522			#ifdef LINUX_24
523			if (v->ether)
524			dev_put(v->ether);
525			#else
526			dev_unlock_list();
527			#endif
528			v->ether = NULL;
529			return err;
530	cebix	1.1	}
531
532	cebix	1.4	/* Get hardware address of the sheep_net module
533			arg: pointer to buffer (6 bytes) to store address */
534	cebix	1.1	case SIOCGIFADDR:
535	cebix	1.4	if (copy_to_user((void *)arg, v->fake_addr, 6))
536			return -EFAULT;
537			return 0;
538
539			/* Set the hardware address of the sheep_net module
540			arg: pointer to new address (6 bytes) */
541			case SIOCSIFADDR:
542			if (copy_from_user(v->fake_addr, (void*)arg, 6))
543	cebix	1.1	return -EFAULT;
544			return 0;
545
546	cebix	1.4	/* Add multicast address
547			arg: pointer to address (6 bytes) */
548	cebix	1.1	case SIOCADDMULTI: {
549			char addr[6];
550			if (v->ether == NULL)
551			return -ENODEV;
552			if (copy_from_user(addr, (void *)arg, 6))
553			return -EFAULT;
554			return dev_mc_add(v->ether, addr, 6, 0);
555			}
556
557	cebix	1.4	/* Remove multicast address
558			arg: pointer to address (6 bytes) */
559	cebix	1.1	case SIOCDELMULTI: {
560			char addr[6];
561			if (v->ether == NULL)
562			return -ENODEV;
563			if (copy_from_user(addr, (void *)arg, 6))
564			return -EFAULT;
565			return dev_mc_delete(v->ether, addr, 6, 0);
566			}
567
568	cebix	1.4	/* Return size of first packet in queue */
569	cebix	1.1	case FIONREAD: {
570			int count = 0;
571			struct sk_buff *skb;
572	cebix	1.4	#ifdef LINUX_24
573	gbeauche	1.12	unsigned long flags;
574	cebix	1.4	spin_lock_irqsave(&v->queue.lock, flags);
575			#else
576			cli();
577			#endif
578	cebix	1.1	skb = skb_peek(&v->queue);
579			if (skb)
580			count = skb->len;
581	cebix	1.4	#ifdef LINUX_24
582			spin_unlock_irqrestore(&v->queue.lock, flags);
583			#else
584			sti();
585			#endif
586	cebix	1.1	return put_user(count, (int *)arg);
587			}
588
589	cebix	1.4	case SIOC_MOL_GET_IPFILTER:
590			return put_user(v->ipfilter, (int *)arg);
591
592			case SIOC_MOL_SET_IPFILTER:
593			v->ipfilter = arg;
594			return 0;
595
596	cebix	1.1	default:
597			return -ENOIOCTLCMD;
598			}
599			}
600
601
602			/*
603			* Packet receiver function
604			*/
605
606	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt)
607	cebix	1.1	{
608	gbeauche	1.12	struct SheepVars v = (struct SheepVars )pt;
609	cebix	1.4	struct sk_buff *skb2;
610			int fake;
611			int multicast;
612	cebix	1.1	D(bug("sheep_net: packet received\n"));
613
614	cebix	1.4	multicast = (skb->mac.ethernet->h_dest[0] & ETH_ADDR_MULTICAST);
615			fake = is_fake_addr(v, &skb->mac.ethernet->h_dest);
616
617			/* Packet sent by us? Then discard */
618			if (is_fake_addr(v, &skb->mac.ethernet->h_source) \|\| skb->protocol == PROT_MAGIC)
619			goto drop;
620
621			/* If the packet is not meant for this host, discard it */
622			if (!is_local_addr(v, &skb->mac.ethernet->h_dest) && !multicast && !fake)
623			goto drop;
624
625			/* Discard packets if queue gets too full */
626			if (skb_queue_len(&v->queue) > MAX_QUEUE)
627			goto drop;
628
629			/* Apply any filters here (if fake is true, then we know we want this packet) */
630			if (!fake) {
631			if ((skb->protocol == htons(ETH_P_IP))
632			&& (!v->ipfilter \|\| (ntohl(skb->h.ipiph->daddr) != v->ipfilter && !multicast)))
633			goto drop;
634	cebix	1.1	}
635
636	cebix	1.4	/* Masquerade (we are typically a clone - best to make a real copy) */
637			skb2 = skb_copy(skb, GFP_ATOMIC);
638			if (!skb2)
639			goto drop;
640			kfree_skb(skb);
641			skb = skb2;
642			masquerade(v, skb);
643	cebix	1.1
644	cebix	1.4	/* We also want the Ethernet header */
645	cebix	1.1	skb_push(skb, skb->data - skb->mac.raw);
646
647	cebix	1.4	/* Enqueue packet */
648	cebix	1.1	skb_queue_tail(&v->queue, skb);
649
650	cebix	1.4	/* Unblock blocked read */
651	cebix	1.1	wake_up(&v->wait);
652	cebix	1.4	return 0;
653
654			drop:
655			kfree_skb(skb);
656	cebix	1.1	return 0;
657			}
658	cebix	1.9
659			MODULE_LICENSE("GPL");