Linux/NetDriver/sheep_net.c

/*
 *  sheep_net.c - Linux driver for SheepShaver/Basilisk II networking (access to raw Ethernet packets)
 *
 *  sheep_net (C) 1999-2001 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
 */

#include <linux/module.h>
#include <linux/version.h>

#if CONFIG_MODVERSIONS == 1
#define MODVERSIONS
#include <linux/modversions.h>
#endif

#if CONFIG_SMP == 1
#define __SMP__
#endif

#include <linux/sched.h>
#include <linux/types.h>
#include <linux/in.h>
#include <linux/fs.h>
#include <asm/uaccess.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/poll.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/ip.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 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
 */

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 */
        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)
                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[8]) */
                case SIOCSIFLINK: {
                        char name[8];
                        int err;

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

                        /* Get Ethernet card name */
                        if (copy_from_user(name, (void *)arg, 8))
                                return -EFAULT;
                        name[7] = 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;
}
Revision:	1.6
Committed:	2001-07-14T15:02:48Z (23 years ago) by cebix
Content type:	text/plain
Branch:	MAIN
Changes since 1.5:	+8 -5 lines
Log Message:	- 1-bit mode under X11 always uses default visual - fixed possible crash in driver_window dtor (image data would be freed twice, once by XDestroyImage() and once in driver_base dtor) - fixed compilation problems with banked memory - fixed typos
#	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	1.3	* sheep_net (C) 1999-2001 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			#include <linux/module.h>
22			#include <linux/version.h>
23	cebix	1.5
24	cebix	1.6	#if CONFIG_MODVERSIONS == 1
25	cebix	1.5	#define MODVERSIONS
26			#include <linux/modversions.h>
27			#endif
28
29	cebix	1.6	#if CONFIG_SMP == 1
30	cebix	1.5	#define __SMP__
31			#endif
32
33	cebix	1.6	#include <linux/sched.h>
34			#include <linux/types.h>
35			#include <linux/in.h>
36			#include <linux/fs.h>
37			#include <asm/uaccess.h>
38
39	cebix	1.1	#include <linux/miscdevice.h>
40			#include <linux/netdevice.h>
41			#include <linux/etherdevice.h>
42			#include <linux/if_ether.h>
43			#include <linux/if_arp.h>
44			#include <linux/poll.h>
45			#include <linux/init.h>
46	cebix	1.4	#include <linux/wait.h>
47	cebix	1.1	#include <net/sock.h>
48	cebix	1.4	#include <net/arp.h>
49			#include <net/ip.h>
50	cebix	1.1
51	cebix	1.5	MODULE_AUTHOR("Christian Bauer");
52			MODULE_DESCRIPTION("Pseudo ethernet device for emulators");
53
54	cebix	1.4	/* Compatibility glue */
55			#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
56			#define LINUX_24
57			#else
58			#define net_device device
59			typedef struct wait_queue *wait_queue_head_t;
60			#define init_waitqueue_head(x) *(x)=NULL
61			#endif
62
63	cebix	1.1	#define DEBUG 0
64
65			#define bug printk
66			#if DEBUG
67			#define D(x) (x);
68			#else
69			#define D(x) ;
70			#endif
71
72
73	cebix	1.4	/* Constants */
74			#define SHEEP_NET_MINOR 198 /* Driver minor number */
75			#define MAX_QUEUE 32 /* Maximum number of packets in queue */
76			#define PROT_MAGIC 1520 /* Our "magic" protocol type */
77	cebix	1.1
78	cebix	1.4	#define ETH_ADDR_MULTICAST 0x1
79
80			#define SIOC_MOL_GET_IPFILTER SIOCDEVPRIVATE
81			#define SIOC_MOL_SET_IPFILTER (SIOCDEVPRIVATE + 1)
82
83			/* Prototypes */
84	cebix	1.1	static int sheep_net_open(struct inode inode, struct file f);
85			static int sheep_net_release(struct inode inode, struct file f);
86			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off);
87			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off);
88			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait);
89			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg);
90	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt);
91	cebix	1.1
92
93			/*
94			* Driver private variables
95			*/
96
97			struct SheepVars {
98	cebix	1.4	struct net_device ether; / The Ethernet device we're attached to */
99			struct sock skt; / Socket for communication with Ethernet card */
100			struct sk_buff_head queue; /* Receiver packet queue */
101			struct packet_type pt; /* Receiver packet type */
102			wait_queue_head_t wait; /* Wait queue for blocking read operations */
103			u32 ipfilter; /* Only receive IP packets destined for this address (host byte order) */
104			char eth_addr[6]; /* Hardware address of the Ethernet card */
105			char fake_addr[6]; /* Local faked hardware address (what SheepShaver sees) */
106	cebix	1.1	};
107
108
109			/*
110			* file_operations structure - has function pointers to the
111			* various entry points for device operations
112			*/
113
114			static struct file_operations sheep_net_fops = {
115	cebix	1.4	read: sheep_net_read,
116			write: sheep_net_write,
117			poll: sheep_net_poll,
118			ioctl: sheep_net_ioctl,
119			open: sheep_net_open,
120			release: sheep_net_release,
121	cebix	1.1	};
122
123
124			/*
125			* miscdevice structure for driver initialization
126			*/
127
128			static struct miscdevice sheep_net_device = {
129	cebix	1.4	SHEEP_NET_MINOR, /* minor number */
130			"sheep_net", /* name */
131	cebix	1.1	&sheep_net_fops,
132			NULL,
133			NULL
134			};
135
136
137			/*
138			* Initialize module
139			*/
140
141			int init_module(void)
142			{
143			int ret;
144
145	cebix	1.4	/* Register driver */
146	cebix	1.1	ret = misc_register(&sheep_net_device);
147			D(bug("Sheep net driver installed\n"));
148			return ret;
149			}
150
151
152			/*
153			* Deinitialize module
154			*/
155
156	cebix	1.5	void cleanup_module(void)
157	cebix	1.1	{
158	cebix	1.4	/* Unregister driver */
159	cebix	1.5	misc_deregister(&sheep_net_device);
160	cebix	1.1	D(bug("Sheep net driver removed\n"));
161			}
162
163
164			/*
165			* Driver open() function
166			*/
167
168			static int sheep_net_open(struct inode inode, struct file f)
169			{
170			struct SheepVars *v;
171			D(bug("sheep_net: open\n"));
172
173	cebix	1.4	/* Must be opened with read permissions */
174	cebix	1.1	if ((f->f_flags & O_ACCMODE) == O_WRONLY)
175			return -EPERM;
176
177	cebix	1.4	/* Allocate private variables */
178	cebix	1.1	v = (struct SheepVars *)f->private_data = kmalloc(sizeof(struct SheepVars), GFP_USER);
179			if (v == NULL)
180			return -ENOMEM;
181			memset(v, 0, sizeof(struct SheepVars));
182			skb_queue_head_init(&v->queue);
183	cebix	1.4	init_waitqueue_head(&v->wait);
184			v->fake_addr[0] = 0xfe;
185			v->fake_addr[1] = 0xfd;
186			v->fake_addr[2] = 0xde;
187			v->fake_addr[3] = 0xad;
188			v->fake_addr[4] = 0xbe;
189			v->fake_addr[5] = 0xef;
190	cebix	1.1
191	cebix	1.4	/* Yes, we're open */
192	cebix	1.1	MOD_INC_USE_COUNT;
193			return 0;
194			}
195
196
197			/*
198			* Driver release() function
199			*/
200
201			static int sheep_net_release(struct inode inode, struct file f)
202			{
203			struct SheepVars v = (struct SheepVars )f->private_data;
204			struct sk_buff *skb;
205			D(bug("sheep_net: close\n"));
206
207	cebix	1.4	/* Detach from Ethernet card */
208	cebix	1.1	if (v->ether) {
209			dev_remove_pack(&v->pt);
210			sk_free(v->skt);
211			v->skt = NULL;
212	cebix	1.4	#ifdef LINUX_24
213			dev_put( v->ether );
214			#endif
215	cebix	1.1	v->ether = NULL;
216			}
217
218	cebix	1.4	/* Empty packet queue */
219	cebix	1.1	while ((skb = skb_dequeue(&v->queue)) != NULL)
220			dev_kfree_skb(skb);
221
222	cebix	1.4	/* Free private variables */
223	cebix	1.1	kfree(v);
224
225	cebix	1.4	/* Sorry, we're closed */
226	cebix	1.1	MOD_DEC_USE_COUNT;
227			return 0;
228			}
229
230
231			/*
232	cebix	1.4	* Check whether an Ethernet address is the local (attached) one or
233			* the fake one
234			*/
235
236			static inline int is_local_addr(struct SheepVars v, void a)
237			{
238			return memcmp(a, v->eth_addr, 6) == 0;
239			}
240
241			static inline int is_fake_addr(struct SheepVars v, void a)
242			{
243			return memcmp(a, v->fake_addr, 6) == 0;
244			}
245
246
247			/*
248			* Outgoing packet. Replace the fake enet addr with the real local one.
249			*/
250
251			static inline void do_demasq(struct SheepVars v, u8 p)
252			{
253			memcpy(p, v->eth_addr, 6);
254			}
255
256			static void demasquerade(struct SheepVars v, struct sk_buff skb)
257			{
258			u8 *p = skb->mac.raw;
259			int proto = (p[12] << 8) \| p[13];
260
261			do_demasq(v, p + 6); /* source address */
262
263			/* Need to fix ARP packets */
264			if (proto == ETH_P_ARP) {
265			if (is_fake_addr(v, p + 14 + 8)) /* sender HW-addr */
266			do_demasq(v, p + 14 + 8);
267			}
268
269			/* ...and AARPs (snap code: 0x00,0x00,0x00,0x80,0xF3) */
270			if (p[17] == 0 && p[18] == 0 && p[19] == 0 && p[20] == 0x80 && p[21] == 0xf3) {
271			/* XXX: we should perhaps look for the 802 frame too */
272			if (is_fake_addr(v, p + 30))
273			do_demasq(v, p + 30); /* sender HW-addr */
274			}
275			}
276
277
278			/*
279			* Incoming packet. Replace the local enet addr with the fake one.
280			*/
281
282			static inline void do_masq(struct SheepVars v, u8 p)
283			{
284			memcpy(p, v->fake_addr, 6);
285			}
286
287			static void masquerade(struct SheepVars v, struct sk_buff skb)
288			{
289			u8 *p = skb->mac.raw;
290			if (!(p[0] & ETH_ADDR_MULTICAST))
291			do_masq(v, p); /* destination address */
292
293			/* XXX: reverse ARP might need to be fixed */
294			}
295
296
297			/*
298	cebix	1.1	* Driver read() function
299			*/
300
301			static ssize_t sheep_net_read(struct file f, char buf, size_t count, loff_t *off)
302			{
303			struct SheepVars v = (struct SheepVars )f->private_data;
304			struct sk_buff *skb;
305	cebix	1.4
306	cebix	1.1	D(bug("sheep_net: read\n"));
307
308			for (;;) {
309
310	cebix	1.4	/* Get next packet from queue */
311	cebix	1.1	skb = skb_dequeue(&v->queue);
312			if (skb != NULL \|\| (f->f_flags & O_NONBLOCK))
313			break;
314
315	cebix	1.4	/* No packet in queue and in blocking mode, so block */
316	cebix	1.1	interruptible_sleep_on(&v->wait);
317
318	cebix	1.4	/* Signal received? Then bail out */
319			if (signal_pending(current))
320			return -EINTR;
321	cebix	1.1	}
322			if (skb == NULL)
323			return -EAGAIN;
324
325	cebix	1.4	/* Pass packet to caller */
326	cebix	1.1	if (count > skb->len)
327			count = skb->len;
328			if (copy_to_user(buf, skb->data, count))
329			count = -EFAULT;
330			dev_kfree_skb(skb);
331			return count;
332			}
333
334
335			/*
336			* Driver write() function
337			*/
338
339			static ssize_t sheep_net_write(struct file f, const char buf, size_t count, loff_t *off)
340			{
341			struct SheepVars v = (struct SheepVars )f->private_data;
342			struct sk_buff *skb;
343			char *p;
344			D(bug("sheep_net: write\n"));
345
346	cebix	1.4	/* Check packet size */
347	cebix	1.1	if (count < sizeof(struct ethhdr))
348			return -EINVAL;
349			if (count > 1514)
350			count = 1514;
351
352	cebix	1.4	/* Interface active? */
353	cebix	1.1	if (v->ether == NULL)
354			return count;
355
356	cebix	1.4	/* Allocate buffer for packet */
357	cebix	1.1	skb = dev_alloc_skb(count);
358			if (skb == NULL)
359			return -ENOBUFS;
360
361	cebix	1.4	/* Stuff packet in buffer */
362	cebix	1.1	p = skb_put(skb, count);
363			if (copy_from_user(p, buf, count)) {
364			kfree_skb(skb);
365			return -EFAULT;
366			}
367
368	cebix	1.4	/* Transmit packet */
369	cebix	1.1	atomic_add(skb->truesize, &v->skt->wmem_alloc);
370			skb->sk = v->skt;
371			skb->dev = v->ether;
372			skb->priority = 0;
373			skb->nh.raw = skb->h.raw = skb->data + v->ether->hard_header_len;
374	cebix	1.4	skb->mac.raw = skb->data;
375
376			/* Base the IP-filtering on the IP address in any outgoing ARP packets */
377			if (skb->mac.ethernet->h_proto == htons(ETH_P_ARP)) {
378			u8 p = &skb->data[14+14]; / source IP address */
379			u32 ip = (p[0] << 24) \| (p[1] << 16) \| (p[2] << 8) \| p[3];
380			if (ip != v->ipfilter) {
381			v->ipfilter = ip;
382			printk("sheep_net: ipfilter set to %d.%d.%d.%d\n", (ip >> 24) & 0xff, (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
383			}
384			}
385
386			/* Is this packet addressed solely to the local host? */
387			if (is_local_addr(v, skb->data) && !(skb->data[0] & ETH_ADDR_MULTICAST)) {
388			skb->protocol = eth_type_trans(skb, v->ether);
389			netif_rx(skb);
390			return count;
391			}
392			if (skb->data[0] & ETH_ADDR_MULTICAST) {
393			/* We can't clone the skb since we will manipulate the data below */
394			struct sk_buff *lskb = skb_copy(skb, GFP_ATOMIC);
395			if (lskb) {
396			lskb->protocol = eth_type_trans(lskb, v->ether);
397			netif_rx(lskb);
398			}
399			}
400
401			/* Outgoing packet (will be on the net) */
402			demasquerade(v, skb);
403
404			skb->protocol = PROT_MAGIC; /* Magic value (we can recognize the packet in sheep_net_receiver) */
405	cebix	1.1	dev_queue_xmit(skb);
406			return count;
407			}
408
409
410			/*
411			* Driver poll() function
412			*/
413
414			static unsigned int sheep_net_poll(struct file f, struct poll_table_struct wait)
415			{
416			struct SheepVars v = (struct SheepVars )f->private_data;
417			D(bug("sheep_net: poll\n"));
418
419	cebix	1.4	/* Packets in queue? Then return */
420			if (!skb_queue_empty(&v->queue))
421	cebix	1.1	return POLLIN \| POLLRDNORM;
422
423	cebix	1.4	/* Otherwise wait for packet */
424	cebix	1.1	poll_wait(f, &v->wait, wait);
425	cebix	1.4	if (!skb_queue_empty(&v->queue))
426	cebix	1.1	return POLLIN \| POLLRDNORM;
427	cebix	1.4	else
428	cebix	1.1	return 0;
429			}
430
431
432			/*
433			* Driver ioctl() function
434			*/
435
436			static int sheep_net_ioctl(struct inode inode, struct file f, unsigned int code, unsigned long arg)
437			{
438			struct SheepVars v = (struct SheepVars )f->private_data;
439			D(bug("sheep_net: ioctl %04x\n", code));
440
441			switch (code) {
442
443	cebix	1.4	/* Attach to Ethernet card
444			arg: pointer to name of Ethernet device (char[8]) */
445	cebix	1.1	case SIOCSIFLINK: {
446			char name[8];
447	cebix	1.4	int err;
448	cebix	1.1
449	cebix	1.4	/* Already attached? */
450	cebix	1.1	if (v->ether)
451			return -EBUSY;
452
453	cebix	1.4	/* Get Ethernet card name */
454	cebix	1.1	if (copy_from_user(name, (void *)arg, 8))
455			return -EFAULT;
456			name[7] = 0;
457
458	cebix	1.4	/* Find card */
459			#ifdef LINUX_24
460			v->ether = dev_get_by_name(name);
461			#else
462	cebix	1.1	dev_lock_list();
463			v->ether = dev_get(name);
464	cebix	1.4	#endif
465	cebix	1.1	if (v->ether == NULL) {
466	cebix	1.4	err = -ENODEV;
467			goto error;
468	cebix	1.1	}
469
470	cebix	1.4	/* Is it Ethernet? */
471	cebix	1.1	if (v->ether->type != ARPHRD_ETHER) {
472	cebix	1.4	err = -EINVAL;
473			goto error;
474	cebix	1.1	}
475
476	cebix	1.4	/* Remember the card's hardware address */
477			memcpy(v->eth_addr, v->ether->dev_addr, 6);
478
479			/* Allocate socket */
480	cebix	1.1	v->skt = sk_alloc(0, GFP_USER, 1);
481			if (v->skt == NULL) {
482	cebix	1.4	err = -ENOMEM;
483			goto error;
484	cebix	1.1	}
485			v->skt->dead = 1;
486
487	cebix	1.4	/* Attach packet handler */
488	cebix	1.1	v->pt.type = htons(ETH_P_ALL);
489			v->pt.dev = v->ether;
490			v->pt.func = sheep_net_receiver;
491			v->pt.data = v;
492			dev_add_pack(&v->pt);
493	cebix	1.4	#ifndef LINUX_24
494	cebix	1.1	dev_unlock_list();
495	cebix	1.4	#endif
496	cebix	1.1	return 0;
497	cebix	1.4
498			error:
499			#ifdef LINUX_24
500			if (v->ether)
501			dev_put(v->ether);
502			#else
503			dev_unlock_list();
504			#endif
505			v->ether = NULL;
506			return err;
507	cebix	1.1	}
508
509	cebix	1.4	/* Get hardware address of the sheep_net module
510			arg: pointer to buffer (6 bytes) to store address */
511	cebix	1.1	case SIOCGIFADDR:
512	cebix	1.4	if (copy_to_user((void *)arg, v->fake_addr, 6))
513			return -EFAULT;
514			return 0;
515
516			/* Set the hardware address of the sheep_net module
517			arg: pointer to new address (6 bytes) */
518			case SIOCSIFADDR:
519			if (copy_from_user(v->fake_addr, (void*)arg, 6))
520	cebix	1.1	return -EFAULT;
521			return 0;
522
523	cebix	1.4	/* Add multicast address
524			arg: pointer to address (6 bytes) */
525	cebix	1.1	case SIOCADDMULTI: {
526			char addr[6];
527			if (v->ether == NULL)
528			return -ENODEV;
529			if (copy_from_user(addr, (void *)arg, 6))
530			return -EFAULT;
531			return dev_mc_add(v->ether, addr, 6, 0);
532			}
533
534	cebix	1.4	/* Remove multicast address
535			arg: pointer to address (6 bytes) */
536	cebix	1.1	case SIOCDELMULTI: {
537			char addr[6];
538			if (v->ether == NULL)
539			return -ENODEV;
540			if (copy_from_user(addr, (void *)arg, 6))
541			return -EFAULT;
542			return dev_mc_delete(v->ether, addr, 6, 0);
543			}
544
545	cebix	1.4	/* Return size of first packet in queue */
546	cebix	1.1	case FIONREAD: {
547			int count = 0;
548			struct sk_buff *skb;
549	cebix	1.4	#ifdef LINUX_24
550			long flags;
551			spin_lock_irqsave(&v->queue.lock, flags);
552			#else
553			cli();
554			#endif
555	cebix	1.1	skb = skb_peek(&v->queue);
556			if (skb)
557			count = skb->len;
558	cebix	1.4	#ifdef LINUX_24
559			spin_unlock_irqrestore(&v->queue.lock, flags);
560			#else
561			sti();
562			#endif
563	cebix	1.1	return put_user(count, (int *)arg);
564			}
565
566	cebix	1.4	case SIOC_MOL_GET_IPFILTER:
567			return put_user(v->ipfilter, (int *)arg);
568
569			case SIOC_MOL_SET_IPFILTER:
570			v->ipfilter = arg;
571			return 0;
572
573	cebix	1.1	default:
574			return -ENOIOCTLCMD;
575			}
576			}
577
578
579			/*
580			* Packet receiver function
581			*/
582
583	cebix	1.4	static int sheep_net_receiver(struct sk_buff skb, struct net_device dev, struct packet_type *pt)
584	cebix	1.1	{
585			struct SheepVars v = (struct SheepVars )pt->data;
586	cebix	1.4	struct sk_buff *skb2;
587			int fake;
588			int multicast;
589	cebix	1.1	D(bug("sheep_net: packet received\n"));
590
591	cebix	1.4	multicast = (skb->mac.ethernet->h_dest[0] & ETH_ADDR_MULTICAST);
592			fake = is_fake_addr(v, &skb->mac.ethernet->h_dest);
593
594			/* Packet sent by us? Then discard */
595			if (is_fake_addr(v, &skb->mac.ethernet->h_source) \|\| skb->protocol == PROT_MAGIC)
596			goto drop;
597
598			/* If the packet is not meant for this host, discard it */
599			if (!is_local_addr(v, &skb->mac.ethernet->h_dest) && !multicast && !fake)
600			goto drop;
601
602			/* Discard packets if queue gets too full */
603			if (skb_queue_len(&v->queue) > MAX_QUEUE)
604			goto drop;
605
606			/* Apply any filters here (if fake is true, then we know we want this packet) */
607			if (!fake) {
608			if ((skb->protocol == htons(ETH_P_IP))
609			&& (!v->ipfilter \|\| (ntohl(skb->h.ipiph->daddr) != v->ipfilter && !multicast)))
610			goto drop;
611	cebix	1.1	}
612
613	cebix	1.4	/* Masquerade (we are typically a clone - best to make a real copy) */
614			skb2 = skb_copy(skb, GFP_ATOMIC);
615			if (!skb2)
616			goto drop;
617			kfree_skb(skb);
618			skb = skb2;
619			masquerade(v, skb);
620	cebix	1.1
621	cebix	1.4	/* We also want the Ethernet header */
622	cebix	1.1	skb_push(skb, skb->data - skb->mac.raw);
623
624	cebix	1.4	/* Enqueue packet */
625	cebix	1.1	skb_queue_tail(&v->queue, skb);
626
627	cebix	1.4	/* Unblock blocked read */
628	cebix	1.1	wake_up(&v->wait);
629	cebix	1.4	return 0;
630
631			drop:
632			kfree_skb(skb);
633	cebix	1.1	return 0;
634			}