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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [net/] [ipv4/] [packet.c] - Blame information for rev 1772

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/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              PACKET - implements raw packet sockets.
 *
 *              Doesn't belong in IP but it's currently too hooked into ip
 *              to separate.
 *
 * Version:     @(#)packet.c    1.0.6   05/25/93
 *
 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 *
 * Fixes:
 *              Alan Cox        :       verify_area() now used correctly
 *              Alan Cox        :       new skbuff lists, look ma no backlogs!
 *              Alan Cox        :       tidied skbuff lists.
 *              Alan Cox        :       Now uses generic datagram routines I
 *                                      added. Also fixed the peek/read crash
 *                                      from all old Linux datagram code.
 *              Alan Cox        :       Uses the improved datagram code.
 *              Alan Cox        :       Added NULL's for socket options.
 *              Alan Cox        :       Re-commented the code.
 *              Alan Cox        :       Use new kernel side addressing
 *              Rob Janssen     :       Correct MTU usage.
 *              Dave Platt      :       Counter leaks caused by incorrect
 *                                      interrupt locking and some slightly
 *                                      dubious gcc output. Can you read
 *                                      compiler: it said _VOLATILE_
 *      Richard Kooijman        :       Timestamp fixes.
 *              Alan Cox        :       New buffers. Use sk->mac.raw.
 *              Alan Cox        :       sendmsg/recvmsg support.
 *              Alan Cox        :       Protocol setting support
 *
 *              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.
 *
 */
 
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_packet.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <asm/segment.h>
 
/*
 *      We really ought to have a single public _inline_ min function!
 */
 
static unsigned long min(unsigned long a, unsigned long b)
{
        if (a < b)
                return(a);
        return(b);
}
 
 
/*
 *      This should be the easiest of all, all we do is copy it into a buffer.
 */
 
int packet_rcv(struct sk_buff *skb, struct device *dev,  struct packet_type *pt)
{
        struct sock *sk;
 
        /*
         *      When we registered the protocol we saved the socket in the data
         *      field for just this event.
         */
 
        sk = (struct sock *) pt->data;
 
        /*
         *      Yank back the headers [hope the device set this
         *      right or kerboom...]
         */
 
        skb_push(skb,skb->data-skb->mac.raw);
 
        /*
         *      The SOCK_PACKET socket receives _all_ frames.
         */
 
        skb->dev = dev;
 
        /*
         *      Charge the memory to the socket. This is done specifically
         *      to prevent sockets using all the memory up.
         */
 
        if(sock_queue_rcv_skb(sk,skb)<0)
        {
                skb->sk = NULL;
                kfree_skb(skb, FREE_READ);
                return 0;
        }
        /*
         *      Processing complete.
         */
 
        return(0);
}
 
 
/*
 *      Output a raw packet to a device layer. This bypasses all the other
 *      protocol layers and you must therefore supply it with a complete frame
 */
 
static int packet_sendmsg(struct sock *sk, struct msghdr *msg, int len,
              int noblock, int flags)
{
        struct sk_buff *skb;
        struct device *dev;
        struct sockaddr_pkt *saddr=(struct sockaddr_pkt *)msg->msg_name;
        unsigned short proto=0;
 
        /*
         *      Check the flags.
         */
 
        if (flags)
                return(-EINVAL);
 
        /*
         *      Get and verify the address.
         */
 
        if (saddr)
        {
                if (msg->msg_namelen < sizeof(struct sockaddr))
                        return(-EINVAL);
                if (msg->msg_namelen==sizeof(struct sockaddr_pkt))
                        proto=saddr->spkt_protocol;
        }
        else
                return(-ENOTCONN);      /* SOCK_PACKET must be sent giving an address */
 
        /*
         *      Find the device first to size check it
         */
 
        saddr->spkt_device[13] = 0;
        dev = dev_get(saddr->spkt_device);
        if (dev == NULL)
        {
                return(-ENODEV);
        }
 
        /*
         *      You may not queue a frame bigger than the mtu. This is the lowest level
         *      raw protocol and you must do your own fragmentation at this level.
         */
 
        if ((dev->flags & IFF_SOFTHEADERS && len>dev->mtu)
        || len>dev->mtu+dev->hard_header_len)
                return -EMSGSIZE;
 
        skb = sock_wmalloc(sk, len+dev->hard_header_len, 0, GFP_KERNEL);
 
        /*
         *      If the write buffer is full, then tough. At this level the user gets to
         *      deal with the problem - do your own algorithmic backoffs. That's far
         *      more flexible.
         */
 
        if (skb == NULL)
        {
                return(-ENOBUFS);
        }
 
        /*
         *      Fill it in
         */
 
        skb->sk = sk;
        skb->free = 1;
        if (dev->flags & IFF_SOFTHEADERS) {
                /* Do the hard header calls for drivers that must set the
                 * headers at transmission time by themselves. PPP and ISDN
                 * are the notable offenders here. A proper fix requires some
                 * changes at the device driver level, but that is a 2.1 issue.
                 */
                skb_reserve(skb,dev->hard_header_len);
                if (dev->hard_header)
                        dev->hard_header(skb,dev,ETH_P_IP,NULL,NULL,len);
        }
        memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
        skb->arp = 1;           /* No ARP needs doing on this (complete) frame */
        skb->protocol = proto;
 
        /*
         *      Now send it
         */
 
        if (dev->flags & IFF_UP)
                dev_queue_xmit(skb, dev, sk->priority);
        else
                kfree_skb(skb, FREE_WRITE);
        return(len);
}
 
/*
 *      Close a SOCK_PACKET socket. This is fairly simple. We immediately go
 *      to 'closed' state and remove our protocol entry in the device list.
 *      The release_sock() will destroy the socket if a user has closed the
 *      file side of the object.
 */
 
static void packet_close(struct sock *sk, unsigned long timeout)
{
        /*
         *      Stop more data and kill the socket off.
         */
 
        lock_sock(sk);
        sk->state = TCP_CLOSE;
 
        /*
         *      Unhook the notifier
         */
 
        unregister_netdevice_notifier(&sk->protinfo.af_packet.notifier);
 
        if(sk->protinfo.af_packet.prot_hook)
        {
                /*
                 *      Remove the protocol hook
                 */
 
                dev_remove_pack((struct packet_type *)sk->protinfo.af_packet.prot_hook);
 
                /*
                 *      Dispose of litter carefully.
                 */
 
                kfree_s((void *)sk->protinfo.af_packet.prot_hook, sizeof(struct packet_type));
                sk->protinfo.af_packet.prot_hook = NULL;
        }
 
        release_sock(sk);
        destroy_sock(sk);
}
 
/*
 *      Attach a packet hook to a device.
 */
 
int packet_attach(struct sock *sk, struct device *dev)
{
        struct packet_type *p = (struct packet_type *) kmalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL)
                return(-ENOMEM);
 
        p->func = packet_rcv;
        p->type = sk->num;
        p->data = (void *)sk;
        p->dev = dev;
        dev_add_pack(p);
 
        /*
         *      We need to remember this somewhere.
         */
 
        sk->protinfo.af_packet.prot_hook = p;
        sk->protinfo.af_packet.bound_dev = dev;
        return 0;
}
 
/*
 *      Bind a packet socket to a device
 */
 
static int packet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
        char name[15];
        struct device *dev;
 
        /*
         *      Check legality
         */
 
        if(addr_len!=sizeof(struct sockaddr))
                return -EINVAL;
        strncpy(name,uaddr->sa_data,14);
        name[14]=0;
 
        /*
         *      Lock the device chain while we sanity check
         *      the bind request.
         */
 
        dev_lock_list();
        dev=dev_get(name);
        if(dev==NULL)
        {
                dev_unlock_list();
                return -ENODEV;
        }
 
        if(!(dev->flags&IFF_UP))
        {
                dev_unlock_list();
                return -ENETDOWN;
        }
 
        /*
         *      Perform the request.
         */
 
        memcpy(sk->protinfo.af_packet.device_name,name,15);
 
        /*
         *      Rewrite an existing hook if present.
         */
 
        if(sk->protinfo.af_packet.prot_hook)
        {
                dev_remove_pack(sk->protinfo.af_packet.prot_hook);
                sk->protinfo.af_packet.prot_hook->dev=dev;
                sk->protinfo.af_packet.bound_dev=dev;
                dev_add_pack(sk->protinfo.af_packet.prot_hook);
        }
        else
        {
                int err=packet_attach(sk, dev);
                if(err)
                {
                        dev_unlock_list();
                        return err;
                }
        }
        /*
         *      Now the notifier is set up right this lot is safe.
         */
        dev_unlock_list();
        return 0;
}
 
/*
 *      This hook is called when a device goes up or down so that
 *      SOCK_PACKET sockets can come unbound properly.
 */
 
static int packet_unbind(struct notifier_block *this, unsigned long msg, void *data)
{
        struct inet_packet_opt *ipo=(struct inet_packet_opt *)this;
        if(msg==NETDEV_DOWN && data==ipo->bound_dev)
        {
                /*
                 *      Our device has gone down.
                 */
                ipo->bound_dev=NULL;
                dev_remove_pack(ipo->prot_hook);
                kfree(ipo->prot_hook);
                ipo->prot_hook=NULL;
        }
        return NOTIFY_DONE;
}
 
 
/*
 *      Create a packet of type SOCK_PACKET.
 */
 
static int packet_init(struct sock *sk)
{
        /*
         *      Attach a protocol block
         */
 
        int err=packet_attach(sk, NULL);
        if(err)
                return err;
 
        /*
         *      Set up the per socket notifier.
         */
 
        sk->protinfo.af_packet.notifier.notifier_call=packet_unbind;
        sk->protinfo.af_packet.notifier.priority=0;
 
        register_netdevice_notifier(&sk->protinfo.af_packet.notifier);
 
        return(0);
}
 
 
/*
 *      Pull a packet from our receive queue and hand it to the user.
 *      If necessary we block.
 */
 
int packet_recvmsg(struct sock *sk, struct msghdr *msg, int len,
                int noblock, int flags,int *addr_len)
{
        int copied=0;
        struct sk_buff *skb;
        struct sockaddr_pkt *saddr=(struct sockaddr_pkt *)msg->msg_name;
        int err;
 
        if (sk->shutdown & RCV_SHUTDOWN)
                return(0);
 
        /*
         *      If there is no protocol hook then the device is down.
         */
 
        if(sk->protinfo.af_packet.prot_hook==NULL)
                return -ENETDOWN;
 
        /*
         *      If the address length field is there to be filled in, we fill
         *      it in now.
         */
 
        if (addr_len)
                *addr_len=sizeof(*saddr);
 
        /*
         *      Call the generic datagram receiver. This handles all sorts
         *      of horrible races and re-entrancy so we can forget about it
         *      in the protocol layers.
         */
 
        skb=skb_recv_datagram(sk,flags,noblock,&err);
 
        /*
         *      An error occurred so return it. Because skb_recv_datagram()
         *      handles the blocking we don't see and worry about blocking
         *      retries.
         */
 
        if(skb==NULL)
                return err;
 
        /*
         *      You lose any data beyond the buffer you gave. If it worries a
         *      user program they can ask the device for its MTU anyway.
         */
 
        copied = min(len, skb->len);
 
        memcpy_toiovec(msg->msg_iov, skb->data, copied);        /* We can't use skb_copy_datagram here */
        sk->stamp=skb->stamp;
 
        /*
         *      Copy the address.
         */
 
        if (saddr)
        {
                saddr->spkt_family = skb->dev->type;
                strncpy(saddr->spkt_device,skb->dev->name, 15);
                saddr->spkt_protocol = skb->protocol;
        }
 
        /*
         *      Free or return the buffer as appropriate. Again this hides all the
         *      races and re-entrancy issues from us.
         */
 
        skb_free_datagram(sk, skb);
 
        return(copied);
}
 
/*
 *      This structure declares to the lower layer socket subsystem currently
 *      incorrectly embedded in the IP code how to behave. This interface needs
 *      a lot of work and will change.
 */
 
struct proto packet_prot =
{
        (struct sock *)&packet_prot,    /* sklist_next */
        (struct sock *)&packet_prot,    /* sklist_prev */
        packet_close,                   /* close */
        ip_build_header,                /* build_header, Not actually used */
        NULL,                           /* connect */
        NULL,                           /* accept */
        ip_queue_xmit,                  /* queue_xmit, These two are not actually used */
        NULL,                           /* retransmit */
        NULL,                           /* write_wakeup */
        NULL,                           /* read_wakeup */
        NULL,                           /* rcv */
        datagram_select,                /* select */
        NULL,                           /* ioctl, No ioctl */
        packet_init,                    /* init */
        NULL,                           /* shutdown */
        NULL,                           /* setsockopt, No set/get socket options */
        NULL,                           /* getsockopt */
        packet_sendmsg,                 /* sendmsg */
        packet_recvmsg,                 /* recvmsg */
        packet_bind,                    /* bind */
        NULL,                           /* hash */
        NULL,                           /* unhash */
        NULL,                           /* rehash */
        NULL,                           /* good_socknum */
        NULL,                           /* verify_bind */
        128,                            /* max_header */
        0,                               /* retransmits */
        "PACKET",                       /* name */
        0,                               /* inuse */
 
};

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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [net/] [ipv4/] [packet.c] - Blame information for rev 1772

Line No.	Rev	Author	Line
1	1629	jcastillo	`/*`
2			`* INET An implementation of the TCP/IP protocol suite for the LINUX`
3			`* operating system. INET is implemented using the BSD Socket`
4			`* interface as the means of communication with the user level.`
5			`*`
6			`* PACKET - implements raw packet sockets.`
7			`*`
8			`* Doesn't belong in IP but it's currently too hooked into ip`
9			`* to separate.`
10			`*`
11			`* Version: @(#)packet.c 1.0.6 05/25/93`
12			`*`
13			`* Authors: Ross Biro, <bir7@leland.Stanford.Edu>`
14			`* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>`
15			`* Alan Cox, <gw4pts@gw4pts.ampr.org>`
16			`*`
17			`* Fixes:`
18			`* Alan Cox : verify_area() now used correctly`
19			`* Alan Cox : new skbuff lists, look ma no backlogs!`
20			`* Alan Cox : tidied skbuff lists.`
21			`* Alan Cox : Now uses generic datagram routines I`
22			`* added. Also fixed the peek/read crash`
23			`* from all old Linux datagram code.`
24			`* Alan Cox : Uses the improved datagram code.`
25			`* Alan Cox : Added NULL's for socket options.`
26			`* Alan Cox : Re-commented the code.`
27			`* Alan Cox : Use new kernel side addressing`
28			`* Rob Janssen : Correct MTU usage.`
29			`* Dave Platt : Counter leaks caused by incorrect`
30			`* interrupt locking and some slightly`
31			`* dubious gcc output. Can you read`
32			`* compiler: it said _VOLATILE_`
33			`* Richard Kooijman : Timestamp fixes.`
34			`* Alan Cox : New buffers. Use sk->mac.raw.`
35			`* Alan Cox : sendmsg/recvmsg support.`
36			`* Alan Cox : Protocol setting support`
37			`*`
38			`* This program is free software; you can redistribute it and/or`
39			`* modify it under the terms of the GNU General Public License`
40			`* as published by the Free Software Foundation; either version`
41			`* 2 of the License, or (at your option) any later version.`
42			`*`
43			`*/`
44
45			`#include <linux/types.h>`
46			`#include <linux/sched.h>`
47			`#include <linux/mm.h>`
48			`#include <linux/fcntl.h>`
49			`#include <linux/socket.h>`
50			`#include <linux/in.h>`
51			`#include <linux/inet.h>`
52			`#include <linux/netdevice.h>`
53			`#include <linux/if_packet.h>`
54			`#include <net/ip.h>`
55			`#include <net/protocol.h>`
56			`#include <linux/skbuff.h>`
57			`#include <net/sock.h>`
58			`#include <linux/errno.h>`
59			`#include <linux/timer.h>`
60			`#include <asm/system.h>`
61			`#include <asm/segment.h>`
62
63			`/*`
64			`* We really ought to have a single public _inline_ min function!`
65			`*/`
66
67			`static unsigned long min(unsigned long a, unsigned long b)`
68			`{`
69			`if (a < b)`
70			`return(a);`
71			`return(b);`
72			`}`
73
74
75			`/*`
76			`* This should be the easiest of all, all we do is copy it into a buffer.`
77			`*/`
78
79			`int packet_rcv(struct sk_buff skb, struct device dev, struct packet_type *pt)`
80			`{`
81			`struct sock *sk;`
82
83			`/*`
84			`* When we registered the protocol we saved the socket in the data`
85			`* field for just this event.`
86			`*/`
87
88			`sk = (struct sock *) pt->data;`
89
90			`/*`
91			`* Yank back the headers [hope the device set this`
92			`* right or kerboom...]`
93			`*/`
94
95			`skb_push(skb,skb->data-skb->mac.raw);`
96
97			`/*`
98			`* The SOCK_PACKET socket receives _all_ frames.`
99			`*/`
100
101			`skb->dev = dev;`
102
103			`/*`
104			`* Charge the memory to the socket. This is done specifically`
105			`* to prevent sockets using all the memory up.`
106			`*/`
107
108			`if(sock_queue_rcv_skb(sk,skb)<0)`
109			`{`
110			`skb->sk = NULL;`
111			`kfree_skb(skb, FREE_READ);`
112			`return 0;`
113			`}`
114			`/*`
115			`* Processing complete.`
116			`*/`
117
118			`return(0);`
119			`}`
120
121
122			`/*`
123			`* Output a raw packet to a device layer. This bypasses all the other`
124			`* protocol layers and you must therefore supply it with a complete frame`
125			`*/`
126
127			`static int packet_sendmsg(struct sock sk, struct msghdr msg, int len,`
128			`int noblock, int flags)`
129			`{`
130			`struct sk_buff *skb;`
131			`struct device *dev;`
132			`struct sockaddr_pkt saddr=(struct sockaddr_pkt )msg->msg_name;`
133			`unsigned short proto=0;`
134
135			`/*`
136			`* Check the flags.`
137			`*/`
138
139			`if (flags)`
140			`return(-EINVAL);`
141
142			`/*`
143			`* Get and verify the address.`
144			`*/`
145
146			`if (saddr)`
147			`{`
148			`if (msg->msg_namelen < sizeof(struct sockaddr))`
149			`return(-EINVAL);`
150			`if (msg->msg_namelen==sizeof(struct sockaddr_pkt))`
151			`proto=saddr->spkt_protocol;`
152			`}`
153			`else`
154			`return(-ENOTCONN); /* SOCK_PACKET must be sent giving an address */`
155
156			`/*`
157			`* Find the device first to size check it`
158			`*/`
159
160			`saddr->spkt_device[13] = 0;`
161			`dev = dev_get(saddr->spkt_device);`
162			`if (dev == NULL)`
163			`{`
164			`return(-ENODEV);`
165			`}`
166
167			`/*`
168			`* You may not queue a frame bigger than the mtu. This is the lowest level`
169			`* raw protocol and you must do your own fragmentation at this level.`
170			`*/`
171
172			`if ((dev->flags & IFF_SOFTHEADERS && len>dev->mtu)`
173			`\|\| len>dev->mtu+dev->hard_header_len)`
174			`return -EMSGSIZE;`
175
176			`skb = sock_wmalloc(sk, len+dev->hard_header_len, 0, GFP_KERNEL);`
177
178			`/*`
179			`* If the write buffer is full, then tough. At this level the user gets to`
180			`* deal with the problem - do your own algorithmic backoffs. That's far`
181			`* more flexible.`
182			`*/`
183
184			`if (skb == NULL)`
185			`{`
186			`return(-ENOBUFS);`
187			`}`
188
189			`/*`
190			`* Fill it in`
191			`*/`
192
193			`skb->sk = sk;`
194			`skb->free = 1;`
195			`if (dev->flags & IFF_SOFTHEADERS) {`
196			`/* Do the hard header calls for drivers that must set the`
197			`* headers at transmission time by themselves. PPP and ISDN`
198			`* are the notable offenders here. A proper fix requires some`
199			`* changes at the device driver level, but that is a 2.1 issue.`
200			`*/`
201			`skb_reserve(skb,dev->hard_header_len);`
202			`if (dev->hard_header)`
203			`dev->hard_header(skb,dev,ETH_P_IP,NULL,NULL,len);`
204			`}`
205			`memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);`
206			`skb->arp = 1; /* No ARP needs doing on this (complete) frame */`
207			`skb->protocol = proto;`
208
209			`/*`
210			`* Now send it`
211			`*/`
212
213			`if (dev->flags & IFF_UP)`
214			`dev_queue_xmit(skb, dev, sk->priority);`
215			`else`
216			`kfree_skb(skb, FREE_WRITE);`
217			`return(len);`
218			`}`
219
220			`/*`
221			`* Close a SOCK_PACKET socket. This is fairly simple. We immediately go`
222			`* to 'closed' state and remove our protocol entry in the device list.`
223			`* The release_sock() will destroy the socket if a user has closed the`
224			`* file side of the object.`
225			`*/`
226
227			`static void packet_close(struct sock *sk, unsigned long timeout)`
228			`{`
229			`/*`
230			`* Stop more data and kill the socket off.`
231			`*/`
232
233			`lock_sock(sk);`
234			`sk->state = TCP_CLOSE;`
235
236			`/*`
237			`* Unhook the notifier`
238			`*/`
239
240			`unregister_netdevice_notifier(&sk->protinfo.af_packet.notifier);`
241
242			`if(sk->protinfo.af_packet.prot_hook)`
243			`{`
244			`/*`
245			`* Remove the protocol hook`
246			`*/`
247
248			`dev_remove_pack((struct packet_type *)sk->protinfo.af_packet.prot_hook);`
249
250			`/*`
251			`* Dispose of litter carefully.`
252			`*/`
253
254			`kfree_s((void *)sk->protinfo.af_packet.prot_hook, sizeof(struct packet_type));`
255			`sk->protinfo.af_packet.prot_hook = NULL;`
256			`}`
257
258			`release_sock(sk);`
259			`destroy_sock(sk);`
260			`}`
261
262			`/*`
263			`* Attach a packet hook to a device.`
264			`*/`
265
266			`int packet_attach(struct sock sk, struct device dev)`
267			`{`
268			`struct packet_type p = (struct packet_type ) kmalloc(sizeof(*p), GFP_KERNEL);`
269			`if (p == NULL)`
270			`return(-ENOMEM);`
271
272			`p->func = packet_rcv;`
273			`p->type = sk->num;`
274			`p->data = (void *)sk;`
275			`p->dev = dev;`
276			`dev_add_pack(p);`
277
278			`/*`
279			`* We need to remember this somewhere.`
280			`*/`
281
282			`sk->protinfo.af_packet.prot_hook = p;`
283			`sk->protinfo.af_packet.bound_dev = dev;`
284			`return 0;`
285			`}`
286
287			`/*`
288			`* Bind a packet socket to a device`
289			`*/`
290
291			`static int packet_bind(struct sock sk, struct sockaddr uaddr, int addr_len)`
292			`{`
293			`char name[15];`
294			`struct device *dev;`
295
296			`/*`
297			`* Check legality`
298			`*/`
299
300			`if(addr_len!=sizeof(struct sockaddr))`
301			`return -EINVAL;`
302			`strncpy(name,uaddr->sa_data,14);`
303			`name[14]=0;`
304
305			`/*`
306			`* Lock the device chain while we sanity check`
307			`* the bind request.`
308			`*/`
309
310			`dev_lock_list();`
311			`dev=dev_get(name);`
312			`if(dev==NULL)`
313			`{`
314			`dev_unlock_list();`
315			`return -ENODEV;`
316			`}`
317
318			`if(!(dev->flags&IFF_UP))`
319			`{`
320			`dev_unlock_list();`
321			`return -ENETDOWN;`
322			`}`
323
324			`/*`
325			`* Perform the request.`
326			`*/`
327
328			`memcpy(sk->protinfo.af_packet.device_name,name,15);`
329
330			`/*`
331			`* Rewrite an existing hook if present.`
332			`*/`
333
334			`if(sk->protinfo.af_packet.prot_hook)`
335			`{`
336			`dev_remove_pack(sk->protinfo.af_packet.prot_hook);`
337			`sk->protinfo.af_packet.prot_hook->dev=dev;`
338			`sk->protinfo.af_packet.bound_dev=dev;`
339			`dev_add_pack(sk->protinfo.af_packet.prot_hook);`
340			`}`
341			`else`
342			`{`
343			`int err=packet_attach(sk, dev);`
344			`if(err)`
345			`{`
346			`dev_unlock_list();`
347			`return err;`
348			`}`
349			`}`
350			`/*`
351			`* Now the notifier is set up right this lot is safe.`
352			`*/`
353			`dev_unlock_list();`
354			`return 0;`
355			`}`
356
357			`/*`
358			`* This hook is called when a device goes up or down so that`
359			`* SOCK_PACKET sockets can come unbound properly.`
360			`*/`
361
362			`static int packet_unbind(struct notifier_block this, unsigned long msg, void data)`
363			`{`
364			`struct inet_packet_opt ipo=(struct inet_packet_opt )this;`
365			`if(msg==NETDEV_DOWN && data==ipo->bound_dev)`
366			`{`
367			`/*`
368			`* Our device has gone down.`
369			`*/`
370			`ipo->bound_dev=NULL;`
371			`dev_remove_pack(ipo->prot_hook);`
372			`kfree(ipo->prot_hook);`
373			`ipo->prot_hook=NULL;`
374			`}`
375			`return NOTIFY_DONE;`
376			`}`
377
378
379			`/*`
380			`* Create a packet of type SOCK_PACKET.`
381			`*/`
382
383			`static int packet_init(struct sock *sk)`
384			`{`
385			`/*`
386			`* Attach a protocol block`
387			`*/`
388
389			`int err=packet_attach(sk, NULL);`
390			`if(err)`
391			`return err;`
392
393			`/*`
394			`* Set up the per socket notifier.`
395			`*/`
396
397			`sk->protinfo.af_packet.notifier.notifier_call=packet_unbind;`
398			`sk->protinfo.af_packet.notifier.priority=0;`
399
400			`register_netdevice_notifier(&sk->protinfo.af_packet.notifier);`
401
402			`return(0);`
403			`}`
404
405
406			`/*`
407			`* Pull a packet from our receive queue and hand it to the user.`
408			`* If necessary we block.`
409			`*/`
410
411			`int packet_recvmsg(struct sock sk, struct msghdr msg, int len,`
412			`int noblock, int flags,int *addr_len)`
413			`{`
414			`int copied=0;`
415			`struct sk_buff *skb;`
416			`struct sockaddr_pkt saddr=(struct sockaddr_pkt )msg->msg_name;`
417			`int err;`
418
419			`if (sk->shutdown & RCV_SHUTDOWN)`
420			`return(0);`
421
422			`/*`
423			`* If there is no protocol hook then the device is down.`
424			`*/`
425
426			`if(sk->protinfo.af_packet.prot_hook==NULL)`
427			`return -ENETDOWN;`
428
429			`/*`
430			`* If the address length field is there to be filled in, we fill`
431			`* it in now.`
432			`*/`
433
434			`if (addr_len)`
435			`addr_len=sizeof(saddr);`
436
437			`/*`
438			`* Call the generic datagram receiver. This handles all sorts`
439			`* of horrible races and re-entrancy so we can forget about it`
440			`* in the protocol layers.`
441			`*/`
442
443			`skb=skb_recv_datagram(sk,flags,noblock,&err);`
444
445			`/*`
446			`* An error occurred so return it. Because skb_recv_datagram()`
447			`* handles the blocking we don't see and worry about blocking`
448			`* retries.`
449			`*/`
450
451			`if(skb==NULL)`
452			`return err;`
453
454			`/*`
455			`* You lose any data beyond the buffer you gave. If it worries a`
456			`* user program they can ask the device for its MTU anyway.`
457			`*/`
458
459			`copied = min(len, skb->len);`
460
461			`memcpy_toiovec(msg->msg_iov, skb->data, copied); /* We can't use skb_copy_datagram here */`
462			`sk->stamp=skb->stamp;`
463
464			`/*`
465			`* Copy the address.`
466			`*/`
467
468			`if (saddr)`
469			`{`
470			`saddr->spkt_family = skb->dev->type;`
471			`strncpy(saddr->spkt_device,skb->dev->name, 15);`
472			`saddr->spkt_protocol = skb->protocol;`
473			`}`
474
475			`/*`
476			`* Free or return the buffer as appropriate. Again this hides all the`
477			`* races and re-entrancy issues from us.`
478			`*/`
479
480			`skb_free_datagram(sk, skb);`
481
482			`return(copied);`
483			`}`
484
485			`/*`
486			`* This structure declares to the lower layer socket subsystem currently`
487			`* incorrectly embedded in the IP code how to behave. This interface needs`
488			`* a lot of work and will change.`
489			`*/`
490
491			`struct proto packet_prot =`
492			`{`
493			`(struct sock )&packet_prot, / sklist_next */`
494			`(struct sock )&packet_prot, / sklist_prev */`
495			`packet_close, /* close */`
496			`ip_build_header, /* build_header, Not actually used */`
497			`NULL, /* connect */`
498			`NULL, /* accept */`
499			`ip_queue_xmit, /* queue_xmit, These two are not actually used */`
500			`NULL, /* retransmit */`
501			`NULL, /* write_wakeup */`
502			`NULL, /* read_wakeup */`
503			`NULL, /* rcv */`
504			`datagram_select, /* select */`
505			`NULL, /* ioctl, No ioctl */`
506			`packet_init, /* init */`
507			`NULL, /* shutdown */`
508			`NULL, /* setsockopt, No set/get socket options */`
509			`NULL, /* getsockopt */`
510			`packet_sendmsg, /* sendmsg */`
511			`packet_recvmsg, /* recvmsg */`
512			`packet_bind, /* bind */`
513			`NULL, /* hash */`
514			`NULL, /* unhash */`
515			`NULL, /* rehash */`
516			`NULL, /* good_socknum */`
517			`NULL, /* verify_bind */`
518			`128, /* max_header */`
519			`0, /* retransmits */`
520			`"PACKET", /* name */`
521			`0, /* inuse */`
522
523			`};`