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 <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(2,4,0)
#define LINUX_24
#else
#define net_device device
typedef struct wait_queue *wait_queue_head_t;
#define init_waitqueue_head(x) *(x)=NULL
#endif

#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 {
        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 */
        struct packet_type pt;          /* Receiver packet type */
        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 = {
        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 = {
        SHEEP_NET_MINOR,        /* minor number */
        "sheep_net",            /* name */
        &sheep_net_fops,
        NULL,
        NULL
};


/*
 *  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
 */

int cleanup_module(void)
{
        int ret;

        /* Unregister driver */
        ret = misc_deregister(&sheep_net_device);
        D(bug("Sheep net driver removed\n"));
        return ret;
}


/*
 *  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 */
        MOD_INC_USE_COUNT;
        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 */
        MOD_DEC_USE_COUNT;
        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 = sk_alloc(0, GFP_USER, 1);
                        if (v->skt == NULL) {
                                err = -ENOMEM;
                                goto error;
                        }
                        v->skt->dead = 1;

                        /* Attach packet handler */
                        v->pt.type = htons(ETH_P_ALL);
                        v->pt.dev = v->ether;
                        v->pt.func = sheep_net_receiver;
                        v->pt.data = v;
                        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
                        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->data;
        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:	1.11
Committed:	2004-01-12T15:54:46Z (20 years, 6 months ago) by cebix
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-16, nigel-build-15
Changes since 1.10:	+1 -1 lines
Log Message:	Happy New Year!
#	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	cebix	1.4	#include <net/arp.h>
49			#include <net/ip.h>
50	cebix	1.7	#include <linux/in.h>
51			#include <linux/wait.h>
52	cebix	1.1
53	cebix	1.5	MODULE_AUTHOR("Christian Bauer");
54			MODULE_DESCRIPTION("Pseudo ethernet device for emulators");
55
56	cebix	1.4	/* Compatibility glue */
57			#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
58			#define LINUX_24
59			#else
60			#define net_device device
61			typedef struct wait_queue *wait_queue_head_t;
62			#define init_waitqueue_head(x) *(x)=NULL
63			#endif
64
65	cebix	1.1	#define DEBUG 0
66
67			#define bug printk
68			#if DEBUG
69			#define D(x) (x);
70			#else
71			#define D(x) ;
72			#endif
73
74
75	cebix	1.4	/* Constants */
76			#define SHEEP_NET_MINOR 198 /* Driver minor number */
77			#define MAX_QUEUE 32 /* Maximum number of packets in queue */
78			#define PROT_MAGIC 1520 /* Our "magic" protocol type */
79	cebix	1.1
80	cebix	1.4	#define ETH_ADDR_MULTICAST 0x1
81	cebix	1.7	#define ETH_ADDR_LOCALLY_DEFINED 0x02
82	cebix	1.4
83			#define SIOC_MOL_GET_IPFILTER SIOCDEVPRIVATE
84			#define SIOC_MOL_SET_IPFILTER (SIOCDEVPRIVATE + 1)
85
86			/* Prototypes */
87	cebix	1.1	static int sheep_net_open(struct inode inode, struct file f);
88			static int sheep_net_release(struct inode inode, struct file f);
89			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off);
90			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off);
91			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait);
92			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg);
93	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt);
94	cebix	1.1
95
96			/*
97			* Driver private variables
98			*/
99
100			struct SheepVars {
101	cebix	1.4	struct net_device ether; / The Ethernet device we're attached to */
102			struct sock skt; / Socket for communication with Ethernet card */
103			struct sk_buff_head queue; /* Receiver packet queue */
104			struct packet_type pt; /* Receiver packet type */
105			wait_queue_head_t wait; /* Wait queue for blocking read operations */
106			u32 ipfilter; /* Only receive IP packets destined for this address (host byte order) */
107			char eth_addr[6]; /* Hardware address of the Ethernet card */
108			char fake_addr[6]; /* Local faked hardware address (what SheepShaver sees) */
109	cebix	1.1	};
110
111
112			/*
113			* file_operations structure - has function pointers to the
114			* various entry points for device operations
115			*/
116
117			static struct file_operations sheep_net_fops = {
118	cebix	1.4	read: sheep_net_read,
119			write: sheep_net_write,
120			poll: sheep_net_poll,
121			ioctl: sheep_net_ioctl,
122			open: sheep_net_open,
123			release: sheep_net_release,
124	cebix	1.1	};
125
126
127			/*
128			* miscdevice structure for driver initialization
129			*/
130
131			static struct miscdevice sheep_net_device = {
132	cebix	1.4	SHEEP_NET_MINOR, /* minor number */
133			"sheep_net", /* name */
134	cebix	1.1	&sheep_net_fops,
135			NULL,
136			NULL
137			};
138
139
140			/*
141			* Initialize module
142			*/
143
144			int init_module(void)
145			{
146			int ret;
147
148	cebix	1.4	/* Register driver */
149	cebix	1.1	ret = misc_register(&sheep_net_device);
150			D(bug("Sheep net driver installed\n"));
151			return ret;
152			}
153
154
155			/*
156			* Deinitialize module
157			*/
158
159	cebix	1.7	int cleanup_module(void)
160	cebix	1.1	{
161	cebix	1.7	int ret;
162
163	cebix	1.4	/* Unregister driver */
164	cebix	1.7	ret = misc_deregister(&sheep_net_device);
165	cebix	1.1	D(bug("Sheep net driver removed\n"));
166	cebix	1.7	return ret;
167	cebix	1.1	}
168
169
170			/*
171			* Driver open() function
172			*/
173
174			static int sheep_net_open(struct inode inode, struct file f)
175			{
176			struct SheepVars *v;
177			D(bug("sheep_net: open\n"));
178
179	cebix	1.4	/* Must be opened with read permissions */
180	cebix	1.1	if ((f->f_flags & O_ACCMODE) == O_WRONLY)
181			return -EPERM;
182
183	cebix	1.4	/* Allocate private variables */
184	cebix	1.1	v = (struct SheepVars *)f->private_data = kmalloc(sizeof(struct SheepVars), GFP_USER);
185			if (v == NULL)
186			return -ENOMEM;
187			memset(v, 0, sizeof(struct SheepVars));
188			skb_queue_head_init(&v->queue);
189	cebix	1.4	init_waitqueue_head(&v->wait);
190			v->fake_addr[0] = 0xfe;
191			v->fake_addr[1] = 0xfd;
192			v->fake_addr[2] = 0xde;
193			v->fake_addr[3] = 0xad;
194			v->fake_addr[4] = 0xbe;
195			v->fake_addr[5] = 0xef;
196	cebix	1.1
197	cebix	1.4	/* Yes, we're open */
198	cebix	1.1	MOD_INC_USE_COUNT;
199			return 0;
200			}
201
202
203			/*
204			* Driver release() function
205			*/
206
207			static int sheep_net_release(struct inode inode, struct file f)
208			{
209			struct SheepVars v = (struct SheepVars )f->private_data;
210			struct sk_buff *skb;
211			D(bug("sheep_net: close\n"));
212
213	cebix	1.4	/* Detach from Ethernet card */
214	cebix	1.1	if (v->ether) {
215			dev_remove_pack(&v->pt);
216			sk_free(v->skt);
217			v->skt = NULL;
218	cebix	1.4	#ifdef LINUX_24
219			dev_put( v->ether );
220			#endif
221	cebix	1.1	v->ether = NULL;
222			}
223
224	cebix	1.4	/* Empty packet queue */
225	cebix	1.1	while ((skb = skb_dequeue(&v->queue)) != NULL)
226			dev_kfree_skb(skb);
227
228	cebix	1.4	/* Free private variables */
229	cebix	1.1	kfree(v);
230
231	cebix	1.4	/* Sorry, we're closed */
232	cebix	1.1	MOD_DEC_USE_COUNT;
233			return 0;
234			}
235
236
237			/*
238	cebix	1.4	* Check whether an Ethernet address is the local (attached) one or
239			* the fake one
240			*/
241
242			static inline int is_local_addr(struct SheepVars v, void a)
243			{
244			return memcmp(a, v->eth_addr, 6) == 0;
245			}
246
247			static inline int is_fake_addr(struct SheepVars v, void a)
248			{
249			return memcmp(a, v->fake_addr, 6) == 0;
250			}
251
252
253			/*
254			* Outgoing packet. Replace the fake enet addr with the real local one.
255			*/
256
257			static inline void do_demasq(struct SheepVars v, u8 p)
258			{
259			memcpy(p, v->eth_addr, 6);
260			}
261
262			static void demasquerade(struct SheepVars v, struct sk_buff skb)
263			{
264			u8 *p = skb->mac.raw;
265			int proto = (p[12] << 8) \| p[13];
266
267			do_demasq(v, p + 6); /* source address */
268
269			/* Need to fix ARP packets */
270			if (proto == ETH_P_ARP) {
271			if (is_fake_addr(v, p + 14 + 8)) /* sender HW-addr */
272			do_demasq(v, p + 14 + 8);
273			}
274
275			/* ...and AARPs (snap code: 0x00,0x00,0x00,0x80,0xF3) */
276			if (p[17] == 0 && p[18] == 0 && p[19] == 0 && p[20] == 0x80 && p[21] == 0xf3) {
277			/* XXX: we should perhaps look for the 802 frame too */
278			if (is_fake_addr(v, p + 30))
279			do_demasq(v, p + 30); /* sender HW-addr */
280			}
281			}
282
283
284			/*
285			* Incoming packet. Replace the local enet addr with the fake one.
286			*/
287
288			static inline void do_masq(struct SheepVars v, u8 p)
289			{
290			memcpy(p, v->fake_addr, 6);
291			}
292
293			static void masquerade(struct SheepVars v, struct sk_buff skb)
294			{
295			u8 *p = skb->mac.raw;
296			if (!(p[0] & ETH_ADDR_MULTICAST))
297			do_masq(v, p); /* destination address */
298
299			/* XXX: reverse ARP might need to be fixed */
300			}
301
302
303			/*
304	cebix	1.1	* Driver read() function
305			*/
306
307			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off)
308			{
309			struct SheepVars v = (struct SheepVars )f->private_data;
310			struct sk_buff *skb;
311	cebix	1.4
312	cebix	1.1	D(bug("sheep_net: read\n"));
313
314			for (;;) {
315
316	cebix	1.4	/* Get next packet from queue */
317	cebix	1.1	skb = skb_dequeue(&v->queue);
318			if (skb != NULL \|\| (f->f_flags & O_NONBLOCK))
319			break;
320
321	cebix	1.4	/* No packet in queue and in blocking mode, so block */
322	cebix	1.1	interruptible_sleep_on(&v->wait);
323
324	cebix	1.4	/* Signal received? Then bail out */
325			if (signal_pending(current))
326			return -EINTR;
327	cebix	1.1	}
328			if (skb == NULL)
329			return -EAGAIN;
330
331	cebix	1.4	/* Pass packet to caller */
332	cebix	1.1	if (count > skb->len)
333			count = skb->len;
334			if (copy_to_user(buf, skb->data, count))
335			count = -EFAULT;
336			dev_kfree_skb(skb);
337			return count;
338			}
339
340
341			/*
342			* Driver write() function
343			*/
344
345			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off)
346			{
347			struct SheepVars v = (struct SheepVars )f->private_data;
348			struct sk_buff *skb;
349			char *p;
350			D(bug("sheep_net: write\n"));
351
352	cebix	1.4	/* Check packet size */
353	cebix	1.1	if (count < sizeof(struct ethhdr))
354			return -EINVAL;
355	cebix	1.7	if (count > 1514) {
356			printk("sheep_net_write: packet size > 1514\n");
357	cebix	1.1	count = 1514;
358	cebix	1.7	}
359	cebix	1.1
360	cebix	1.4	/* Interface active? */
361	cebix	1.1	if (v->ether == NULL)
362			return count;
363
364	cebix	1.4	/* Allocate buffer for packet */
365	cebix	1.1	skb = dev_alloc_skb(count);
366			if (skb == NULL)
367			return -ENOBUFS;
368
369	cebix	1.4	/* Stuff packet in buffer */
370	cebix	1.1	p = skb_put(skb, count);
371			if (copy_from_user(p, buf, count)) {
372			kfree_skb(skb);
373			return -EFAULT;
374			}
375
376	cebix	1.4	/* Transmit packet */
377	cebix	1.1	atomic_add(skb->truesize, &v->skt->wmem_alloc);
378			skb->sk = v->skt;
379			skb->dev = v->ether;
380			skb->priority = 0;
381			skb->nh.raw = skb->h.raw = skb->data + v->ether->hard_header_len;
382	cebix	1.4	skb->mac.raw = skb->data;
383
384			/* Base the IP-filtering on the IP address in any outgoing ARP packets */
385			if (skb->mac.ethernet->h_proto == htons(ETH_P_ARP)) {
386			u8 p = &skb->data[14+14]; / source IP address */
387			u32 ip = (p[0] << 24) \| (p[1] << 16) \| (p[2] << 8) \| p[3];
388			if (ip != v->ipfilter) {
389			v->ipfilter = ip;
390			printk("sheep_net: ipfilter set to %d.%d.%d.%d\n", (ip >> 24) & 0xff, (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
391			}
392			}
393
394			/* Is this packet addressed solely to the local host? */
395			if (is_local_addr(v, skb->data) && !(skb->data[0] & ETH_ADDR_MULTICAST)) {
396			skb->protocol = eth_type_trans(skb, v->ether);
397			netif_rx(skb);
398			return count;
399			}
400			if (skb->data[0] & ETH_ADDR_MULTICAST) {
401			/* We can't clone the skb since we will manipulate the data below */
402			struct sk_buff *lskb = skb_copy(skb, GFP_ATOMIC);
403			if (lskb) {
404			lskb->protocol = eth_type_trans(lskb, v->ether);
405			netif_rx(lskb);
406			}
407			}
408
409			/* Outgoing packet (will be on the net) */
410			demasquerade(v, skb);
411
412			skb->protocol = PROT_MAGIC; /* Magic value (we can recognize the packet in sheep_net_receiver) */
413	cebix	1.1	dev_queue_xmit(skb);
414			return count;
415			}
416
417
418			/*
419			* Driver poll() function
420			*/
421
422			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait)
423			{
424			struct SheepVars v = (struct SheepVars )f->private_data;
425			D(bug("sheep_net: poll\n"));
426
427	cebix	1.4	/* Packets in queue? Then return */
428			if (!skb_queue_empty(&v->queue))
429	cebix	1.1	return POLLIN \| POLLRDNORM;
430
431	cebix	1.4	/* Otherwise wait for packet */
432	cebix	1.1	poll_wait(f, &v->wait, wait);
433	cebix	1.4	if (!skb_queue_empty(&v->queue))
434	cebix	1.1	return POLLIN \| POLLRDNORM;
435	cebix	1.4	else
436	cebix	1.1	return 0;
437			}
438
439
440			/*
441			* Driver ioctl() function
442			*/
443
444			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg)
445			{
446			struct SheepVars v = (struct SheepVars )f->private_data;
447			D(bug("sheep_net: ioctl %04x\n", code));
448
449			switch (code) {
450
451	cebix	1.4	/* Attach to Ethernet card
452	cebix	1.7	arg: pointer to name of Ethernet device (char[20]) */
453	cebix	1.1	case SIOCSIFLINK: {
454	cebix	1.7	char name[20];
455	cebix	1.4	int err;
456	cebix	1.1
457	cebix	1.4	/* Already attached? */
458	cebix	1.1	if (v->ether)
459			return -EBUSY;
460
461	cebix	1.4	/* Get Ethernet card name */
462	cebix	1.7	if (copy_from_user(name, (void *)arg, 20))
463	cebix	1.1	return -EFAULT;
464	cebix	1.7	name[19] = 0;
465	cebix	1.1
466	cebix	1.4	/* Find card */
467			#ifdef LINUX_24
468			v->ether = dev_get_by_name(name);
469			#else
470	cebix	1.1	dev_lock_list();
471			v->ether = dev_get(name);
472	cebix	1.4	#endif
473	cebix	1.1	if (v->ether == NULL) {
474	cebix	1.4	err = -ENODEV;
475			goto error;
476	cebix	1.1	}
477
478	cebix	1.4	/* Is it Ethernet? */
479	cebix	1.1	if (v->ether->type != ARPHRD_ETHER) {
480	cebix	1.4	err = -EINVAL;
481			goto error;
482	cebix	1.1	}
483
484	cebix	1.4	/* Remember the card's hardware address */
485			memcpy(v->eth_addr, v->ether->dev_addr, 6);
486
487			/* Allocate socket */
488	cebix	1.1	v->skt = sk_alloc(0, GFP_USER, 1);
489			if (v->skt == NULL) {
490	cebix	1.4	err = -ENOMEM;
491			goto error;
492	cebix	1.1	}
493			v->skt->dead = 1;
494
495	cebix	1.4	/* Attach packet handler */
496	cebix	1.1	v->pt.type = htons(ETH_P_ALL);
497			v->pt.dev = v->ether;
498			v->pt.func = sheep_net_receiver;
499			v->pt.data = v;
500			dev_add_pack(&v->pt);
501	cebix	1.4	#ifndef LINUX_24
502	cebix	1.1	dev_unlock_list();
503	cebix	1.4	#endif
504	cebix	1.1	return 0;
505	cebix	1.4
506			error:
507			#ifdef LINUX_24
508			if (v->ether)
509			dev_put(v->ether);
510			#else
511			dev_unlock_list();
512			#endif
513			v->ether = NULL;
514			return err;
515	cebix	1.1	}
516
517	cebix	1.4	/* Get hardware address of the sheep_net module
518			arg: pointer to buffer (6 bytes) to store address */
519	cebix	1.1	case SIOCGIFADDR:
520	cebix	1.4	if (copy_to_user((void *)arg, v->fake_addr, 6))
521			return -EFAULT;
522			return 0;
523
524			/* Set the hardware address of the sheep_net module
525			arg: pointer to new address (6 bytes) */
526			case SIOCSIFADDR:
527			if (copy_from_user(v->fake_addr, (void*)arg, 6))
528	cebix	1.1	return -EFAULT;
529			return 0;
530
531	cebix	1.4	/* Add multicast address
532			arg: pointer to address (6 bytes) */
533	cebix	1.1	case SIOCADDMULTI: {
534			char addr[6];
535			if (v->ether == NULL)
536			return -ENODEV;
537			if (copy_from_user(addr, (void *)arg, 6))
538			return -EFAULT;
539			return dev_mc_add(v->ether, addr, 6, 0);
540			}
541
542	cebix	1.4	/* Remove multicast address
543			arg: pointer to address (6 bytes) */
544	cebix	1.1	case SIOCDELMULTI: {
545			char addr[6];
546			if (v->ether == NULL)
547			return -ENODEV;
548			if (copy_from_user(addr, (void *)arg, 6))
549			return -EFAULT;
550			return dev_mc_delete(v->ether, addr, 6, 0);
551			}
552
553	cebix	1.4	/* Return size of first packet in queue */
554	cebix	1.1	case FIONREAD: {
555			int count = 0;
556			struct sk_buff *skb;
557	cebix	1.4	#ifdef LINUX_24
558			long flags;
559			spin_lock_irqsave(&v->queue.lock, flags);
560			#else
561			cli();
562			#endif
563	cebix	1.1	skb = skb_peek(&v->queue);
564			if (skb)
565			count = skb->len;
566	cebix	1.4	#ifdef LINUX_24
567			spin_unlock_irqrestore(&v->queue.lock, flags);
568			#else
569			sti();
570			#endif
571	cebix	1.1	return put_user(count, (int *)arg);
572			}
573
574	cebix	1.4	case SIOC_MOL_GET_IPFILTER:
575			return put_user(v->ipfilter, (int *)arg);
576
577			case SIOC_MOL_SET_IPFILTER:
578			v->ipfilter = arg;
579			return 0;
580
581	cebix	1.1	default:
582			return -ENOIOCTLCMD;
583			}
584			}
585
586
587			/*
588			* Packet receiver function
589			*/
590
591	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt)
592	cebix	1.1	{
593			struct SheepVars v = (struct SheepVars )pt->data;
594	cebix	1.4	struct sk_buff *skb2;
595			int fake;
596			int multicast;
597	cebix	1.1	D(bug("sheep_net: packet received\n"));
598
599	cebix	1.4	multicast = (skb->mac.ethernet->h_dest[0] & ETH_ADDR_MULTICAST);
600			fake = is_fake_addr(v, &skb->mac.ethernet->h_dest);
601
602			/* Packet sent by us? Then discard */
603			if (is_fake_addr(v, &skb->mac.ethernet->h_source) \|\| skb->protocol == PROT_MAGIC)
604			goto drop;
605
606			/* If the packet is not meant for this host, discard it */
607			if (!is_local_addr(v, &skb->mac.ethernet->h_dest) && !multicast && !fake)
608			goto drop;
609
610			/* Discard packets if queue gets too full */
611			if (skb_queue_len(&v->queue) > MAX_QUEUE)
612			goto drop;
613
614			/* Apply any filters here (if fake is true, then we know we want this packet) */
615			if (!fake) {
616			if ((skb->protocol == htons(ETH_P_IP))
617			&& (!v->ipfilter \|\| (ntohl(skb->h.ipiph->daddr) != v->ipfilter && !multicast)))
618			goto drop;
619	cebix	1.1	}
620
621	cebix	1.4	/* Masquerade (we are typically a clone - best to make a real copy) */
622			skb2 = skb_copy(skb, GFP_ATOMIC);
623			if (!skb2)
624			goto drop;
625			kfree_skb(skb);
626			skb = skb2;
627			masquerade(v, skb);
628	cebix	1.1
629	cebix	1.4	/* We also want the Ethernet header */
630	cebix	1.1	skb_push(skb, skb->data - skb->mac.raw);
631
632	cebix	1.4	/* Enqueue packet */
633	cebix	1.1	skb_queue_tail(&v->queue, skb);
634
635	cebix	1.4	/* Unblock blocked read */
636	cebix	1.1	wake_up(&v->wait);
637	cebix	1.4	return 0;
638
639			drop:
640			kfree_skb(skb);
641	cebix	1.1	return 0;
642			}
643	cebix	1.9
644			MODULE_LICENSE("GPL");