Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  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  * Authors:     Ross Biro
  9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 10  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 11  *
 12  * Fixes:
 13  *              Alan Cox        :       verify_area() now used correctly
 14  *              Alan Cox        :       new skbuff lists, look ma no backlogs!
 15  *              Alan Cox        :       tidied skbuff lists.
 16  *              Alan Cox        :       Now uses generic datagram routines I
 17  *                                      added. Also fixed the peek/read crash
 18  *                                      from all old Linux datagram code.
 19  *              Alan Cox        :       Uses the improved datagram code.
 20  *              Alan Cox        :       Added NULL's for socket options.
 21  *              Alan Cox        :       Re-commented the code.
 22  *              Alan Cox        :       Use new kernel side addressing
 23  *              Rob Janssen     :       Correct MTU usage.
 24  *              Dave Platt      :       Counter leaks caused by incorrect
 25  *                                      interrupt locking and some slightly
 26  *                                      dubious gcc output. Can you read
 27  *                                      compiler: it said _VOLATILE_
 28  *      Richard Kooijman        :       Timestamp fixes.
 29  *              Alan Cox        :       New buffers. Use sk->mac.raw.
 30  *              Alan Cox        :       sendmsg/recvmsg support.
 31  *              Alan Cox        :       Protocol setting support
 32  *      Alexey Kuznetsov        :       Untied from IPv4 stack.
 33  *      Cyrus Durgin            :       Fixed kerneld for kmod.
 34  *      Michal Ostrowski        :       Module initialization cleanup.
 35  *         Ulises Alonso        :       Frame number limit removal and
 36  *                                      packet_set_ring memory leak.
 37  *              Eric Biederman  :       Allow for > 8 byte hardware addresses.
 38  *                                      The convention is that longer addresses
 39  *                                      will simply extend the hardware address
 40  *                                      byte arrays at the end of sockaddr_ll
 41  *                                      and packet_mreq.
 42  *              Johann Baudy    :       Added TX RING.
 43  *
 44  *              This program is free software; you can redistribute it and/or
 45  *              modify it under the terms of the GNU General Public License
 46  *              as published by the Free Software Foundation; either version
 47  *              2 of the License, or (at your option) any later version.
 48  *
 49  */
 50 
 51 #include <linux/types.h>
 52 #include <linux/mm.h>
 53 #include <linux/capability.h>
 54 #include <linux/fcntl.h>
 55 #include <linux/socket.h>
 56 #include <linux/in.h>
 57 #include <linux/inet.h>
 58 #include <linux/netdevice.h>
 59 #include <linux/if_packet.h>
 60 #include <linux/wireless.h>
 61 #include <linux/kernel.h>
 62 #include <linux/kmod.h>
 63 #include <net/net_namespace.h>
 64 #include <net/ip.h>
 65 #include <net/protocol.h>
 66 #include <linux/skbuff.h>
 67 #include <net/sock.h>
 68 #include <linux/errno.h>
 69 #include <linux/timer.h>
 70 #include <asm/system.h>
 71 #include <asm/uaccess.h>
 72 #include <asm/ioctls.h>
 73 #include <asm/page.h>
 74 #include <asm/cacheflush.h>
 75 #include <asm/io.h>
 76 #include <linux/proc_fs.h>
 77 #include <linux/seq_file.h>
 78 #include <linux/poll.h>
 79 #include <linux/module.h>
 80 #include <linux/init.h>
 81 #include <linux/mutex.h>
 82 
 83 #ifdef CONFIG_INET
 84 #include <net/inet_common.h>
 85 #endif
 86 
 87 /*
 88    Assumptions:
 89    - if device has no dev->hard_header routine, it adds and removes ll header
 90      inside itself. In this case ll header is invisible outside of device,
 91      but higher levels still should reserve dev->hard_header_len.
 92      Some devices are enough clever to reallocate skb, when header
 93      will not fit to reserved space (tunnel), another ones are silly
 94      (PPP).
 95    - packet socket receives packets with pulled ll header,
 96      so that SOCK_RAW should push it back.
 97 
 98 On receive:
 99 -----------
100 
101 Incoming, dev->hard_header!=NULL
102    mac_header -> ll header
103    data       -> data
104 
105 Outgoing, dev->hard_header!=NULL
106    mac_header -> ll header
107    data       -> ll header
108 
109 Incoming, dev->hard_header==NULL
110    mac_header -> UNKNOWN position. It is very likely, that it points to ll
111                  header.  PPP makes it, that is wrong, because introduce
112                  assymetry between rx and tx paths.
113    data       -> data
114 
115 Outgoing, dev->hard_header==NULL
116    mac_header -> data. ll header is still not built!
117    data       -> data
118 
119 Resume
120   If dev->hard_header==NULL we are unlikely to restore sensible ll header.
121 
122 
123 On transmit:
124 ------------
125 
126 dev->hard_header != NULL
127    mac_header -> ll header
128    data       -> ll header
129 
130 dev->hard_header == NULL (ll header is added by device, we cannot control it)
131    mac_header -> data
132    data       -> data
133 
134    We should set nh.raw on output to correct posistion,
135    packet classifier depends on it.
136  */
137 
138 /* Private packet socket structures. */
139 
140 struct packet_mclist
141 {
142         struct packet_mclist    *next;
143         int                     ifindex;
144         int                     count;
145         unsigned short          type;
146         unsigned short          alen;
147         unsigned char           addr[MAX_ADDR_LEN];
148 };
149 /* identical to struct packet_mreq except it has
150  * a longer address field.
151  */
152 struct packet_mreq_max
153 {
154         int             mr_ifindex;
155         unsigned short  mr_type;
156         unsigned short  mr_alen;
157         unsigned char   mr_address[MAX_ADDR_LEN];
158 };
159 
160 #ifdef CONFIG_PACKET_MMAP
161 static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
162                 int closing, int tx_ring);
163 
164 struct packet_ring_buffer {
165         char *                  *pg_vec;
166         unsigned int            head;
167         unsigned int            frames_per_block;
168         unsigned int            frame_size;
169         unsigned int            frame_max;
170 
171         unsigned int            pg_vec_order;
172         unsigned int            pg_vec_pages;
173         unsigned int            pg_vec_len;
174 
175         atomic_t                pending;
176 };
177 
178 struct packet_sock;
179 static int tpacket_snd(struct packet_sock *po, struct msghdr *msg);
180 #endif
181 
182 static void packet_flush_mclist(struct sock *sk);
183 
184 struct packet_sock {
185         /* struct sock has to be the first member of packet_sock */
186         struct sock             sk;
187         struct tpacket_stats    stats;
188 #ifdef CONFIG_PACKET_MMAP
189         struct packet_ring_buffer       rx_ring;
190         struct packet_ring_buffer       tx_ring;
191         int                     copy_thresh;
192 #endif
193         struct packet_type      prot_hook;
194         spinlock_t              bind_lock;
195         struct mutex            pg_vec_lock;
196         unsigned int            running:1,      /* prot_hook is attached*/
197                                 auxdata:1,
198                                 origdev:1;
199         int                     ifindex;        /* bound device         */
200         __be16                  num;
201         struct packet_mclist    *mclist;
202 #ifdef CONFIG_PACKET_MMAP
203         atomic_t                mapped;
204         enum tpacket_versions   tp_version;
205         unsigned int            tp_hdrlen;
206         unsigned int            tp_reserve;
207         unsigned int            tp_loss:1;
208 #endif
209 };
210 
211 struct packet_skb_cb {
212         unsigned int origlen;
213         union {
214                 struct sockaddr_pkt pkt;
215                 struct sockaddr_ll ll;
216         } sa;
217 };
218 
219 #define PACKET_SKB_CB(__skb)    ((struct packet_skb_cb *)((__skb)->cb))
220 
221 #ifdef CONFIG_PACKET_MMAP
222 
223 static void __packet_set_status(struct packet_sock *po, void *frame, int status)
224 {
225         union {
226                 struct tpacket_hdr *h1;
227                 struct tpacket2_hdr *h2;
228                 void *raw;
229         } h;
230 
231         h.raw = frame;
232         switch (po->tp_version) {
233         case TPACKET_V1:
234                 h.h1->tp_status = status;
235                 flush_dcache_page(virt_to_page(&h.h1->tp_status));
236                 break;
237         case TPACKET_V2:
238                 h.h2->tp_status = status;
239                 flush_dcache_page(virt_to_page(&h.h2->tp_status));
240                 break;
241         default:
242                 printk(KERN_ERR "TPACKET version not supported\n");
243                 BUG();
244         }
245 
246         smp_wmb();
247 }
248 
249 static int __packet_get_status(struct packet_sock *po, void *frame)
250 {
251         union {
252                 struct tpacket_hdr *h1;
253                 struct tpacket2_hdr *h2;
254                 void *raw;
255         } h;
256 
257         smp_rmb();
258 
259         h.raw = frame;
260         switch (po->tp_version) {
261         case TPACKET_V1:
262                 flush_dcache_page(virt_to_page(&h.h1->tp_status));
263                 return h.h1->tp_status;
264         case TPACKET_V2:
265                 flush_dcache_page(virt_to_page(&h.h2->tp_status));
266                 return h.h2->tp_status;
267         default:
268                 printk(KERN_ERR "TPACKET version not supported\n");
269                 BUG();
270                 return 0;
271         }
272 }
273 
274 static void *packet_lookup_frame(struct packet_sock *po,
275                 struct packet_ring_buffer *rb,
276                 unsigned int position,
277                 int status)
278 {
279         unsigned int pg_vec_pos, frame_offset;
280         union {
281                 struct tpacket_hdr *h1;
282                 struct tpacket2_hdr *h2;
283                 void *raw;
284         } h;
285 
286         pg_vec_pos = position / rb->frames_per_block;
287         frame_offset = position % rb->frames_per_block;
288 
289         h.raw = rb->pg_vec[pg_vec_pos] + (frame_offset * rb->frame_size);
290 
291         if (status != __packet_get_status(po, h.raw))
292                 return NULL;
293 
294         return h.raw;
295 }
296 
297 static inline void *packet_current_frame(struct packet_sock *po,
298                 struct packet_ring_buffer *rb,
299                 int status)
300 {
301         return packet_lookup_frame(po, rb, rb->head, status);
302 }
303 
304 static inline void *packet_previous_frame(struct packet_sock *po,
305                 struct packet_ring_buffer *rb,
306                 int status)
307 {
308         unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
309         return packet_lookup_frame(po, rb, previous, status);
310 }
311 
312 static inline void packet_increment_head(struct packet_ring_buffer *buff)
313 {
314         buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
315 }
316 
317 #endif
318 
319 static inline struct packet_sock *pkt_sk(struct sock *sk)
320 {
321         return (struct packet_sock *)sk;
322 }
323 
324 static void packet_sock_destruct(struct sock *sk)
325 {
326         WARN_ON(atomic_read(&sk->sk_rmem_alloc));
327         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
328 
329         if (!sock_flag(sk, SOCK_DEAD)) {
330                 printk("Attempt to release alive packet socket: %p\n", sk);
331                 return;
332         }
333 
334         sk_refcnt_debug_dec(sk);
335 }
336 
337 
338 static const struct proto_ops packet_ops;
339 
340 static const struct proto_ops packet_ops_spkt;
341 
342 static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,  struct packet_type *pt, struct net_device *orig_dev)
343 {
344         struct sock *sk;
345         struct sockaddr_pkt *spkt;
346 
347         /*
348          *      When we registered the protocol we saved the socket in the data
349          *      field for just this event.
350          */
351 
352         sk = pt->af_packet_priv;
353 
354         /*
355          *      Yank back the headers [hope the device set this
356          *      right or kerboom...]
357          *
358          *      Incoming packets have ll header pulled,
359          *      push it back.
360          *
361          *      For outgoing ones skb->data == skb_mac_header(skb)
362          *      so that this procedure is noop.
363          */
364 
365         if (skb->pkt_type == PACKET_LOOPBACK)
366                 goto out;
367 
368         if (dev_net(dev) != sock_net(sk))
369                 goto out;
370 
371         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
372                 goto oom;
373 
374         /* drop any routing info */
375         skb_dst_drop(skb);
376 
377         /* drop conntrack reference */
378         nf_reset(skb);
379 
380         spkt = &PACKET_SKB_CB(skb)->sa.pkt;
381 
382         skb_push(skb, skb->data - skb_mac_header(skb));
383 
384         /*
385          *      The SOCK_PACKET socket receives _all_ frames.
386          */
387 
388         spkt->spkt_family = dev->type;
389         strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
390         spkt->spkt_protocol = skb->protocol;
391 
392         /*
393          *      Charge the memory to the socket. This is done specifically
394          *      to prevent sockets using all the memory up.
395          */
396 
397         if (sock_queue_rcv_skb(sk,skb) == 0)
398                 return 0;
399 
400 out:
401         kfree_skb(skb);
402 oom:
403         return 0;
404 }
405 
406 
407 /*
408  *      Output a raw packet to a device layer. This bypasses all the other
409  *      protocol layers and you must therefore supply it with a complete frame
410  */
411 
412 static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock,
413                                struct msghdr *msg, size_t len)
414 {
415         struct sock *sk = sock->sk;
416         struct sockaddr_pkt *saddr=(struct sockaddr_pkt *)msg->msg_name;
417         struct sk_buff *skb;
418         struct net_device *dev;
419         __be16 proto=0;
420         int err;
421 
422         /*
423          *      Get and verify the address.
424          */
425 
426         if (saddr)
427         {
428                 if (msg->msg_namelen < sizeof(struct sockaddr))
429                         return(-EINVAL);
430                 if (msg->msg_namelen==sizeof(struct sockaddr_pkt))
431                         proto=saddr->spkt_protocol;
432         }
433         else
434                 return(-ENOTCONN);      /* SOCK_PACKET must be sent giving an address */
435 
436         /*
437          *      Find the device first to size check it
438          */
439 
440         saddr->spkt_device[13] = 0;
441         dev = dev_get_by_name(sock_net(sk), saddr->spkt_device);
442         err = -ENODEV;
443         if (dev == NULL)
444                 goto out_unlock;
445 
446         err = -ENETDOWN;
447         if (!(dev->flags & IFF_UP))
448                 goto out_unlock;
449 
450         /*
451          *      You may not queue a frame bigger than the mtu. This is the lowest level
452          *      raw protocol and you must do your own fragmentation at this level.
453          */
454 
455         err = -EMSGSIZE;
456         if (len > dev->mtu + dev->hard_header_len)
457                 goto out_unlock;
458 
459         err = -ENOBUFS;
460         skb = sock_wmalloc(sk, len + LL_RESERVED_SPACE(dev), 0, GFP_KERNEL);
461 
462         /*
463          *      If the write buffer is full, then tough. At this level the user gets to
464          *      deal with the problem - do your own algorithmic backoffs. That's far
465          *      more flexible.
466          */
467 
468         if (skb == NULL)
469                 goto out_unlock;
470 
471         /*
472          *      Fill it in
473          */
474 
475         /* FIXME: Save some space for broken drivers that write a
476          * hard header at transmission time by themselves. PPP is the
477          * notable one here. This should really be fixed at the driver level.
478          */
479         skb_reserve(skb, LL_RESERVED_SPACE(dev));
480         skb_reset_network_header(skb);
481 
482         /* Try to align data part correctly */
483         if (dev->header_ops) {
484                 skb->data -= dev->hard_header_len;
485                 skb->tail -= dev->hard_header_len;
486                 if (len < dev->hard_header_len)
487                         skb_reset_network_header(skb);
488         }
489 
490         /* Returns -EFAULT on error */
491         err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
492         skb->protocol = proto;
493         skb->dev = dev;
494         skb->priority = sk->sk_priority;
495         if (err)
496                 goto out_free;
497 
498         /*
499          *      Now send it
500          */
501 
502         dev_queue_xmit(skb);
503         dev_put(dev);
504         return(len);
505 
506 out_free:
507         kfree_skb(skb);
508 out_unlock:
509         if (dev)
510                 dev_put(dev);
511         return err;
512 }
513 
514 static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk,
515                                       unsigned int res)
516 {
517         struct sk_filter *filter;
518 
519         rcu_read_lock_bh();
520         filter = rcu_dereference(sk->sk_filter);
521         if (filter != NULL)
522                 res = sk_run_filter(skb, filter->insns, filter->len);
523         rcu_read_unlock_bh();
524 
525         return res;
526 }
527 
528 /*
529    This function makes lazy skb cloning in hope that most of packets
530    are discarded by BPF.
531 
532    Note tricky part: we DO mangle shared skb! skb->data, skb->len
533    and skb->cb are mangled. It works because (and until) packets
534    falling here are owned by current CPU. Output packets are cloned
535    by dev_queue_xmit_nit(), input packets are processed by net_bh
536    sequencially, so that if we return skb to original state on exit,
537    we will not harm anyone.
538  */
539 
540 static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
541 {
542         struct sock *sk;
543         struct sockaddr_ll *sll;
544         struct packet_sock *po;
545         u8 * skb_head = skb->data;
546         int skb_len = skb->len;
547         unsigned int snaplen, res;
548 
549         if (skb->pkt_type == PACKET_LOOPBACK)
550                 goto drop;
551 
552         sk = pt->af_packet_priv;
553         po = pkt_sk(sk);
554 
555         if (dev_net(dev) != sock_net(sk))
556                 goto drop;
557 
558         skb->dev = dev;
559 
560         if (dev->header_ops) {
561                 /* The device has an explicit notion of ll header,
562                    exported to higher levels.
563 
564                    Otherwise, the device hides datails of it frame
565                    structure, so that corresponding packet head
566                    never delivered to user.
567                  */
568                 if (sk->sk_type != SOCK_DGRAM)
569                         skb_push(skb, skb->data - skb_mac_header(skb));
570                 else if (skb->pkt_type == PACKET_OUTGOING) {
571                         /* Special case: outgoing packets have ll header at head */
572                         skb_pull(skb, skb_network_offset(skb));
573                 }
574         }
575 
576         snaplen = skb->len;
577 
578         res = run_filter(skb, sk, snaplen);
579         if (!res)
580                 goto drop_n_restore;
581         if (snaplen > res)
582                 snaplen = res;
583 
584         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
585             (unsigned)sk->sk_rcvbuf)
586                 goto drop_n_acct;
587 
588         if (skb_shared(skb)) {
589                 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
590                 if (nskb == NULL)
591                         goto drop_n_acct;
592 
593                 if (skb_head != skb->data) {
594                         skb->data = skb_head;
595                         skb->len = skb_len;
596                 }
597                 kfree_skb(skb);
598                 skb = nskb;
599         }
600 
601         BUILD_BUG_ON(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8 >
602                      sizeof(skb->cb));
603 
604         sll = &PACKET_SKB_CB(skb)->sa.ll;
605         sll->sll_family = AF_PACKET;
606         sll->sll_hatype = dev->type;
607         sll->sll_protocol = skb->protocol;
608         sll->sll_pkttype = skb->pkt_type;
609         if (unlikely(po->origdev))
610                 sll->sll_ifindex = orig_dev->ifindex;
611         else
612                 sll->sll_ifindex = dev->ifindex;
613 
614         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
615 
616         PACKET_SKB_CB(skb)->origlen = skb->len;
617 
618         if (pskb_trim(skb, snaplen))
619                 goto drop_n_acct;
620 
621         skb_set_owner_r(skb, sk);
622         skb->dev = NULL;
623         skb_dst_drop(skb);
624 
625         /* drop conntrack reference */
626         nf_reset(skb);
627 
628         spin_lock(&sk->sk_receive_queue.lock);
629         po->stats.tp_packets++;
630         __skb_queue_tail(&sk->sk_receive_queue, skb);
631         spin_unlock(&sk->sk_receive_queue.lock);
632         sk->sk_data_ready(sk, skb->len);
633         return 0;
634 
635 drop_n_acct:
636         spin_lock(&sk->sk_receive_queue.lock);
637         po->stats.tp_drops++;
638         spin_unlock(&sk->sk_receive_queue.lock);
639 
640 drop_n_restore:
641         if (skb_head != skb->data && skb_shared(skb)) {
642                 skb->data = skb_head;
643                 skb->len = skb_len;
644         }
645 drop:
646         consume_skb(skb);
647         return 0;
648 }
649 
650 #ifdef CONFIG_PACKET_MMAP
651 static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
652 {
653         struct sock *sk;
654         struct packet_sock *po;
655         struct sockaddr_ll *sll;
656         union {
657                 struct tpacket_hdr *h1;
658                 struct tpacket2_hdr *h2;
659                 void *raw;
660         } h;
661         u8 * skb_head = skb->data;
662         int skb_len = skb->len;
663         unsigned int snaplen, res;
664         unsigned long status = TP_STATUS_LOSING|TP_STATUS_USER;
665         unsigned short macoff, netoff, hdrlen;
666         struct sk_buff *copy_skb = NULL;
667         struct timeval tv;
668         struct timespec ts;
669 
670         if (skb->pkt_type == PACKET_LOOPBACK)
671                 goto drop;
672 
673         sk = pt->af_packet_priv;
674         po = pkt_sk(sk);
675 
676         if (dev_net(dev) != sock_net(sk))
677                 goto drop;
678 
679         if (dev->header_ops) {
680                 if (sk->sk_type != SOCK_DGRAM)
681                         skb_push(skb, skb->data - skb_mac_header(skb));
682                 else if (skb->pkt_type == PACKET_OUTGOING) {
683                         /* Special case: outgoing packets have ll header at head */
684                         skb_pull(skb, skb_network_offset(skb));
685                 }
686         }
687 
688         if (skb->ip_summed == CHECKSUM_PARTIAL)
689                 status |= TP_STATUS_CSUMNOTREADY;
690 
691         snaplen = skb->len;
692 
693         res = run_filter(skb, sk, snaplen);
694         if (!res)
695                 goto drop_n_restore;
696         if (snaplen > res)
697                 snaplen = res;
698 
699         if (sk->sk_type == SOCK_DGRAM) {
700                 macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
701                                   po->tp_reserve;
702         } else {
703                 unsigned maclen = skb_network_offset(skb);
704                 netoff = TPACKET_ALIGN(po->tp_hdrlen +
705                                        (maclen < 16 ? 16 : maclen)) +
706                         po->tp_reserve;
707                 macoff = netoff - maclen;
708         }
709 
710         if (macoff + snaplen > po->rx_ring.frame_size) {
711                 if (po->copy_thresh &&
712                     atomic_read(&sk->sk_rmem_alloc) + skb->truesize <
713                     (unsigned)sk->sk_rcvbuf) {
714                         if (skb_shared(skb)) {
715                                 copy_skb = skb_clone(skb, GFP_ATOMIC);
716                         } else {
717                                 copy_skb = skb_get(skb);
718                                 skb_head = skb->data;
719                         }
720                         if (copy_skb)
721                                 skb_set_owner_r(copy_skb, sk);
722                 }
723                 snaplen = po->rx_ring.frame_size - macoff;
724                 if ((int)snaplen < 0)
725                         snaplen = 0;
726         }
727 
728         spin_lock(&sk->sk_receive_queue.lock);
729         h.raw = packet_current_frame(po, &po->rx_ring, TP_STATUS_KERNEL);
730         if (!h.raw)
731                 goto ring_is_full;
732         packet_increment_head(&po->rx_ring);
733         po->stats.tp_packets++;
734         if (copy_skb) {
735                 status |= TP_STATUS_COPY;
736                 __skb_queue_tail(&sk->sk_receive_queue, copy_skb);
737         }
738         if (!po->stats.tp_drops)
739                 status &= ~TP_STATUS_LOSING;
740         spin_unlock(&sk->sk_receive_queue.lock);
741 
742         skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
743 
744         switch (po->tp_version) {
745         case TPACKET_V1:
746                 h.h1->tp_len = skb->len;
747                 h.h1->tp_snaplen = snaplen;
748                 h.h1->tp_mac = macoff;
749                 h.h1->tp_net = netoff;
750                 if (skb->tstamp.tv64)
751                         tv = ktime_to_timeval(skb->tstamp);
752                 else
753                         do_gettimeofday(&tv);
754                 h.h1->tp_sec = tv.tv_sec;
755                 h.h1->tp_usec = tv.tv_usec;
756                 hdrlen = sizeof(*h.h1);
757                 break;
758         case TPACKET_V2:
759                 h.h2->tp_len = skb->len;
760                 h.h2->tp_snaplen = snaplen;
761                 h.h2->tp_mac = macoff;
762                 h.h2->tp_net = netoff;
763                 if (skb->tstamp.tv64)
764                         ts = ktime_to_timespec(skb->tstamp);
765                 else
766                         getnstimeofday(&ts);
767                 h.h2->tp_sec = ts.tv_sec;
768                 h.h2->tp_nsec = ts.tv_nsec;
769                 h.h2->tp_vlan_tci = skb->vlan_tci;
770                 hdrlen = sizeof(*h.h2);
771                 break;
772         default:
773                 BUG();
774         }
775 
776         sll = h.raw + TPACKET_ALIGN(hdrlen);
777         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
778         sll->sll_family = AF_PACKET;
779         sll->sll_hatype = dev->type;
780         sll->sll_protocol = skb->protocol;
781         sll->sll_pkttype = skb->pkt_type;
782         if (unlikely(po->origdev))
783                 sll->sll_ifindex = orig_dev->ifindex;
784         else
785                 sll->sll_ifindex = dev->ifindex;
786 
787         __packet_set_status(po, h.raw, status);
788         smp_mb();
789         {
790                 struct page *p_start, *p_end;
791                 u8 *h_end = h.raw + macoff + snaplen - 1;
792 
793                 p_start = virt_to_page(h.raw);
794                 p_end = virt_to_page(h_end);
795                 while (p_start <= p_end) {
796                         flush_dcache_page(p_start);
797                         p_start++;
798                 }
799         }
800 
801         sk->sk_data_ready(sk, 0);
802 
803 drop_n_restore:
804         if (skb_head != skb->data && skb_shared(skb)) {
805                 skb->data = skb_head;
806                 skb->len = skb_len;
807         }
808 drop:
809         kfree_skb(skb);
810         return 0;
811 
812 ring_is_full:
813         po->stats.tp_drops++;
814         spin_unlock(&sk->sk_receive_queue.lock);
815 
816         sk->sk_data_ready(sk, 0);
817         kfree_skb(copy_skb);
818         goto drop_n_restore;
819 }
820 
821 static void tpacket_destruct_skb(struct sk_buff *skb)
822 {
823         struct packet_sock *po = pkt_sk(skb->sk);
824         void * ph;
825 
826         BUG_ON(skb == NULL);
827 
828         if (likely(po->tx_ring.pg_vec)) {
829                 ph = skb_shinfo(skb)->destructor_arg;
830                 BUG_ON(__packet_get_status(po, ph) != TP_STATUS_SENDING);
831                 BUG_ON(atomic_read(&po->tx_ring.pending) == 0);
832                 atomic_dec(&po->tx_ring.pending);
833                 __packet_set_status(po, ph, TP_STATUS_AVAILABLE);
834         }
835 
836         sock_wfree(skb);
837 }
838 
839 static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff * skb,
840                 void * frame, struct net_device *dev, int size_max,
841                 __be16 proto, unsigned char * addr)
842 {
843         union {
844                 struct tpacket_hdr *h1;
845                 struct tpacket2_hdr *h2;
846                 void *raw;
847         } ph;
848         int to_write, offset, len, tp_len, nr_frags, len_max;
849         struct socket *sock = po->sk.sk_socket;
850         struct page *page;
851         void *data;
852         int err;
853 
854         ph.raw = frame;
855 
856         skb->protocol = proto;
857         skb->dev = dev;
858         skb->priority = po->sk.sk_priority;
859         skb_shinfo(skb)->destructor_arg = ph.raw;
860 
861         switch (po->tp_version) {
862         case TPACKET_V2:
863                 tp_len = ph.h2->tp_len;
864                 break;
865         default:
866                 tp_len = ph.h1->tp_len;
867                 break;
868         }
869         if (unlikely(tp_len > size_max)) {
870                 printk(KERN_ERR "packet size is too long (%d > %d)\n",
871                                 tp_len, size_max);
872                 return -EMSGSIZE;
873         }
874 
875         skb_reserve(skb, LL_RESERVED_SPACE(dev));
876         skb_reset_network_header(skb);
877 
878         data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
879         to_write = tp_len;
880 
881         if (sock->type == SOCK_DGRAM) {
882                 err = dev_hard_header(skb, dev, ntohs(proto), addr,
883                                 NULL, tp_len);
884                 if (unlikely(err < 0))
885                         return -EINVAL;
886         } else if (dev->hard_header_len ) {
887                 /* net device doesn't like empty head */
888                 if (unlikely(tp_len <= dev->hard_header_len)) {
889                         printk(KERN_ERR "packet size is too short "
890                                         "(%d < %d)\n", tp_len,
891                                         dev->hard_header_len);
892                         return -EINVAL;
893                 }
894 
895                 skb_push(skb, dev->hard_header_len);
896                 err = skb_store_bits(skb, 0, data,
897                                 dev->hard_header_len);
898                 if (unlikely(err))
899                         return err;
900 
901                 data += dev->hard_header_len;
902                 to_write -= dev->hard_header_len;
903         }
904 
905         err = -EFAULT;
906         page = virt_to_page(data);
907         offset = offset_in_page(data);
908         len_max = PAGE_SIZE - offset;
909         len = ((to_write > len_max) ? len_max : to_write);
910 
911         skb->data_len = to_write;
912         skb->len += to_write;
913         skb->truesize += to_write;
914         atomic_add(to_write, &po->sk.sk_wmem_alloc);
915 
916         while (likely(to_write)) {
917                 nr_frags = skb_shinfo(skb)->nr_frags;
918 
919                 if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
920                         printk(KERN_ERR "Packet exceed the number "
921                                         "of skb frags(%lu)\n",
922                                         MAX_SKB_FRAGS);
923                         return -EFAULT;
924                 }
925 
926                 flush_dcache_page(page);
927                 get_page(page);
928                 skb_fill_page_desc(skb,
929                                 nr_frags,
930                                 page++, offset, len);
931                 to_write -= len;
932                 offset = 0;
933                 len_max = PAGE_SIZE;
934                 len = ((to_write > len_max) ? len_max : to_write);
935         }
936 
937         return tp_len;
938 }
939 
940 static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
941 {
942         struct socket *sock;
943         struct sk_buff *skb;
944         struct net_device *dev;
945         __be16 proto;
946         int ifindex, err, reserve = 0;
947         void * ph;
948         struct sockaddr_ll *saddr=(struct sockaddr_ll *)msg->msg_name;
949         int tp_len, size_max;
950         unsigned char *addr;
951         int len_sum = 0;
952         int status = 0;
953 
954         sock = po->sk.sk_socket;
955 
956         mutex_lock(&po->pg_vec_lock);
957 
958         err = -EBUSY;
959         if (saddr == NULL) {
960                 ifindex = po->ifindex;
961                 proto   = po->num;
962                 addr    = NULL;
963         } else {
964                 err = -EINVAL;
965                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
966                         goto out;
967                 if (msg->msg_namelen < (saddr->sll_halen
968                                         + offsetof(struct sockaddr_ll,
969                                                 sll_addr)))
970                         goto out;
971                 ifindex = saddr->sll_ifindex;
972                 proto   = saddr->sll_protocol;
973                 addr    = saddr->sll_addr;
974         }
975 
976         dev = dev_get_by_index(sock_net(&po->sk), ifindex);
977         err = -ENXIO;
978         if (unlikely(dev == NULL))
979                 goto out;
980 
981         reserve = dev->hard_header_len;
982 
983         err = -ENETDOWN;
984         if (unlikely(!(dev->flags & IFF_UP)))
985                 goto out_put;
986 
987         size_max = po->tx_ring.frame_size
988                 - sizeof(struct skb_shared_info)
989                 - po->tp_hdrlen
990                 - LL_ALLOCATED_SPACE(dev)
991                 - sizeof(struct sockaddr_ll);
992 
993         if (size_max > dev->mtu + reserve)
994                 size_max = dev->mtu + reserve;
995 
996         do {
997                 ph = packet_current_frame(po, &po->tx_ring,
998                                 TP_STATUS_SEND_REQUEST);
999 
1000                 if (unlikely(ph == NULL)) {
1001                         schedule();
1002                         continue;
1003                 }
1004 
1005                 status = TP_STATUS_SEND_REQUEST;
1006                 skb = sock_alloc_send_skb(&po->sk,
1007                                 LL_ALLOCATED_SPACE(dev)
1008                                 + sizeof(struct sockaddr_ll),
1009                                 0, &err);
1010 
1011                 if (unlikely(skb == NULL))
1012                         goto out_status;
1013 
1014                 tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
1015                                 addr);
1016 
1017                 if (unlikely(tp_len < 0)) {
1018                         if (po->tp_loss) {
1019                                 __packet_set_status(po, ph,
1020                                                 TP_STATUS_AVAILABLE);
1021                                 packet_increment_head(&po->tx_ring);
1022                                 kfree_skb(skb);
1023                                 continue;
1024                         } else {
1025                                 status = TP_STATUS_WRONG_FORMAT;
1026                                 err = tp_len;
1027                                 goto out_status;
1028                         }
1029                 }
1030 
1031                 skb->destructor = tpacket_destruct_skb;
1032                 __packet_set_status(po, ph, TP_STATUS_SENDING);
1033                 atomic_inc(&po->tx_ring.pending);
1034 
1035                 status = TP_STATUS_SEND_REQUEST;
1036                 err = dev_queue_xmit(skb);
1037                 if (unlikely(err > 0 && (err = net_xmit_errno(err)) != 0))
1038                         goto out_xmit;
1039                 packet_increment_head(&po->tx_ring);
1040                 len_sum += tp_len;
1041         }
1042         while (likely((ph != NULL) || ((!(msg->msg_flags & MSG_DONTWAIT))
1043                                         && (atomic_read(&po->tx_ring.pending))))
1044               );
1045 
1046         err = len_sum;
1047         goto out_put;
1048 
1049 out_xmit:
1050         skb->destructor = sock_wfree;
1051         atomic_dec(&po->tx_ring.pending);
1052 out_status:
1053         __packet_set_status(po, ph, status);
1054         kfree_skb(skb);
1055 out_put:
1056         dev_put(dev);
1057 out:
1058         mutex_unlock(&po->pg_vec_lock);
1059         return err;
1060 }
1061 #endif
1062 
1063 static int packet_snd(struct socket *sock,
1064                           struct msghdr *msg, size_t len)
1065 {
1066         struct sock *sk = sock->sk;
1067         struct sockaddr_ll *saddr=(struct sockaddr_ll *)msg->msg_name;
1068         struct sk_buff *skb;
1069         struct net_device *dev;
1070         __be16 proto;
1071         unsigned char *addr;
1072         int ifindex, err, reserve = 0;
1073 
1074         /*
1075          *      Get and verify the address.
1076          */
1077 
1078         if (saddr == NULL) {
1079                 struct packet_sock *po = pkt_sk(sk);
1080 
1081                 ifindex = po->ifindex;
1082                 proto   = po->num;
1083                 addr    = NULL;
1084         } else {
1085                 err = -EINVAL;
1086                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
1087                         goto out;
1088                 if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
1089                         goto out;
1090                 ifindex = saddr->sll_ifindex;
1091                 proto   = saddr->sll_protocol;
1092                 addr    = saddr->sll_addr;
1093         }
1094 
1095 
1096         dev = dev_get_by_index(sock_net(sk), ifindex);
1097         err = -ENXIO;
1098         if (dev == NULL)
1099                 goto out_unlock;
1100         if (sock->type == SOCK_RAW)
1101                 reserve = dev->hard_header_len;
1102 
1103         err = -ENETDOWN;
1104         if (!(dev->flags & IFF_UP))
1105                 goto out_unlock;
1106 
1107         err = -EMSGSIZE;
1108         if (len > dev->mtu+reserve)
1109                 goto out_unlock;
1110 
1111         skb = sock_alloc_send_skb(sk, len + LL_ALLOCATED_SPACE(dev),
1112                                 msg->msg_flags & MSG_DONTWAIT, &err);
1113         if (skb==NULL)
1114                 goto out_unlock;
1115 
1116         skb_reserve(skb, LL_RESERVED_SPACE(dev));
1117         skb_reset_network_header(skb);
1118 
1119         err = -EINVAL;
1120         if (sock->type == SOCK_DGRAM &&
1121             dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len) < 0)
1122                 goto out_free;
1123 
1124         /* Returns -EFAULT on error */
1125         err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
1126         if (err)
1127                 goto out_free;
1128 
1129         skb->protocol = proto;
1130         skb->dev = dev;
1131         skb->priority = sk->sk_priority;
1132 
1133         /*
1134          *      Now send it
1135          */
1136 
1137         err = dev_queue_xmit(skb);
1138         if (err > 0 && (err = net_xmit_errno(err)) != 0)
1139                 goto out_unlock;
1140 
1141         dev_put(dev);
1142 
1143         return(len);
1144 
1145 out_free:
1146         kfree_skb(skb);
1147 out_unlock:
1148         if (dev)
1149                 dev_put(dev);
1150 out:
1151         return err;
1152 }
1153 
1154 static int packet_sendmsg(struct kiocb *iocb, struct socket *sock,
1155                 struct msghdr *msg, size_t len)
1156 {
1157 #ifdef CONFIG_PACKET_MMAP
1158         struct sock *sk = sock->sk;
1159         struct packet_sock *po = pkt_sk(sk);
1160         if (po->tx_ring.pg_vec)
1161                 return tpacket_snd(po, msg);
1162         else
1163 #endif
1164                 return packet_snd(sock, msg, len);
1165 }
1166 
1167 /*
1168  *      Close a PACKET socket. This is fairly simple. We immediately go
1169  *      to 'closed' state and remove our protocol entry in the device list.
1170  */
1171 
1172 static int packet_release(struct socket *sock)
1173 {
1174         struct sock *sk = sock->sk;
1175         struct packet_sock *po;
1176         struct net *net;
1177 #ifdef CONFIG_PACKET_MMAP
1178         struct tpacket_req req;
1179 #endif
1180 
1181         if (!sk)
1182                 return 0;
1183 
1184         net = sock_net(sk);
1185         po = pkt_sk(sk);
1186 
1187         write_lock_bh(&net->packet.sklist_lock);
1188         sk_del_node_init(sk);
1189         sock_prot_inuse_add(net, sk->sk_prot, -1);
1190         write_unlock_bh(&net->packet.sklist_lock);
1191 
1192         /*
1193          *      Unhook packet receive handler.
1194          */
1195 
1196         if (po->running) {
1197                 /*
1198                  *      Remove the protocol hook
1199                  */
1200                 dev_remove_pack(&po->prot_hook);
1201                 po->running = 0;
1202                 po->num = 0;
1203                 __sock_put(sk);
1204         }
1205 
1206         packet_flush_mclist(sk);
1207 
1208 #ifdef CONFIG_PACKET_MMAP
1209         memset(&req, 0, sizeof(req));
1210 
1211         if (po->rx_ring.pg_vec)
1212                 packet_set_ring(sk, &req, 1, 0);
1213 
1214         if (po->tx_ring.pg_vec)
1215                 packet_set_ring(sk, &req, 1, 1);
1216 #endif
1217 
1218         /*
1219          *      Now the socket is dead. No more input will appear.
1220          */
1221 
1222         sock_orphan(sk);
1223         sock->sk = NULL;
1224 
1225         /* Purge queues */
1226 
1227         skb_queue_purge(&sk->sk_receive_queue);
1228         sk_refcnt_debug_release(sk);
1229 
1230         sock_put(sk);
1231         return 0;
1232 }
1233 
1234 /*
1235  *      Attach a packet hook.
1236  */
1237 
1238 static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protocol)
1239 {
1240         struct packet_sock *po = pkt_sk(sk);
1241         /*
1242          *      Detach an existing hook if present.
1243          */
1244 
1245         lock_sock(sk);
1246 
1247         spin_lock(&po->bind_lock);
1248         if (po->running) {
1249                 __sock_put(sk);
1250                 po->running = 0;
1251                 po->num = 0;
1252                 spin_unlock(&po->bind_lock);
1253                 dev_remove_pack(&po->prot_hook);
1254                 spin_lock(&po->bind_lock);
1255         }
1256 
1257         po->num = protocol;
1258         po->prot_hook.type = protocol;
1259         po->prot_hook.dev = dev;
1260 
1261         po->ifindex = dev ? dev->ifindex : 0;
1262 
1263         if (protocol == 0)
1264                 goto out_unlock;
1265 
1266         if (!dev || (dev->flags & IFF_UP)) {
1267                 dev_add_pack(&po->prot_hook);
1268                 sock_hold(sk);
1269                 po->running = 1;
1270         } else {
1271                 sk->sk_err = ENETDOWN;
1272                 if (!sock_flag(sk, SOCK_DEAD))
1273                         sk->sk_error_report(sk);
1274         }
1275 
1276 out_unlock:
1277         spin_unlock(&po->bind_lock);
1278         release_sock(sk);
1279         return 0;
1280 }
1281 
1282 /*
1283  *      Bind a packet socket to a device
1284  */
1285 
1286 static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1287 {
1288         struct sock *sk=sock->sk;
1289         char name[15];
1290         struct net_device *dev;
1291         int err = -ENODEV;
1292 
1293         /*
1294          *      Check legality
1295          */
1296 
1297         if (addr_len != sizeof(struct sockaddr))
1298                 return -EINVAL;
1299         strlcpy(name,uaddr->sa_data,sizeof(name));
1300 
1301         dev = dev_get_by_name(sock_net(sk), name);
1302         if (dev) {
1303                 err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
1304                 dev_put(dev);
1305         }
1306         return err;
1307 }
1308 
1309 static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1310 {
1311         struct sockaddr_ll *sll = (struct sockaddr_ll*)uaddr;
1312         struct sock *sk=sock->sk;
1313         struct net_device *dev = NULL;
1314         int err;
1315 
1316 
1317         /*
1318          *      Check legality
1319          */
1320 
1321         if (addr_len < sizeof(struct sockaddr_ll))
1322                 return -EINVAL;
1323         if (sll->sll_family != AF_PACKET)
1324                 return -EINVAL;
1325 
1326         if (sll->sll_ifindex) {
1327                 err = -ENODEV;
1328                 dev = dev_get_by_index(sock_net(sk), sll->sll_ifindex);
1329                 if (dev == NULL)
1330                         goto out;
1331         }
1332         err = packet_do_bind(sk, dev, sll->sll_protocol ? : pkt_sk(sk)->num);
1333         if (dev)
1334                 dev_put(dev);
1335 
1336 out:
1337         return err;
1338 }
1339 
1340 static struct proto packet_proto = {
1341         .name     = "PACKET",
1342         .owner    = THIS_MODULE,
1343         .obj_size = sizeof(struct packet_sock),
1344 };
1345 
1346 /*
1347  *      Create a packet of type SOCK_PACKET.
1348  */
1349 
1350 static int packet_create(struct net *net, struct socket *sock, int protocol)
1351 {
1352         struct sock *sk;
1353         struct packet_sock *po;
1354         __be16 proto = (__force __be16)protocol; /* weird, but documented */
1355         int err;
1356 
1357         if (!capable(CAP_NET_RAW))
1358                 return -EPERM;
1359         if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
1360             sock->type != SOCK_PACKET)
1361                 return -ESOCKTNOSUPPORT;
1362 
1363         sock->state = SS_UNCONNECTED;
1364 
1365         err = -ENOBUFS;
1366         sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto);
1367         if (sk == NULL)
1368                 goto out;
1369 
1370         sock->ops = &packet_ops;
1371         if (sock->type == SOCK_PACKET)
1372                 sock->ops = &packet_ops_spkt;
1373 
1374         sock_init_data(sock, sk);
1375 
1376         po = pkt_sk(sk);
1377         sk->sk_family = PF_PACKET;
1378         po->num = proto;
1379 
1380         sk->sk_destruct = packet_sock_destruct;
1381         sk_refcnt_debug_inc(sk);
1382 
1383         /*
1384          *      Attach a protocol block
1385          */
1386 
1387         spin_lock_init(&po->bind_lock);
1388         mutex_init(&po->pg_vec_lock);
1389         po->prot_hook.func = packet_rcv;
1390 
1391         if (sock->type == SOCK_PACKET)
1392                 po->prot_hook.func = packet_rcv_spkt;
1393 
1394         po->prot_hook.af_packet_priv = sk;
1395 
1396         if (proto) {
1397                 po->prot_hook.type = proto;
1398                 dev_add_pack(&po->prot_hook);
1399                 sock_hold(sk);
1400                 po->running = 1;
1401         }
1402 
1403         write_lock_bh(&net->packet.sklist_lock);
1404         sk_add_node(sk, &net->packet.sklist);
1405         sock_prot_inuse_add(net, &packet_proto, 1);
1406         write_unlock_bh(&net->packet.sklist_lock);
1407         return(0);
1408 out:
1409         return err;
1410 }
1411 
1412 /*
1413  *      Pull a packet from our receive queue and hand it to the user.
1414  *      If necessary we block.
1415  */
1416 
1417 static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
1418                           struct msghdr *msg, size_t len, int flags)
1419 {
1420         struct sock *sk = sock->sk;
1421         struct sk_buff *skb;
1422         int copied, err;
1423         struct sockaddr_ll *sll;
1424 
1425         err = -EINVAL;
1426         if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT))
1427                 goto out;
1428 
1429 #if 0
1430         /* What error should we return now? EUNATTACH? */
1431         if (pkt_sk(sk)->ifindex < 0)
1432                 return -ENODEV;
1433 #endif
1434 
1435         /*
1436          *      Call the generic datagram receiver. This handles all sorts
1437          *      of horrible races and re-entrancy so we can forget about it
1438          *      in the protocol layers.
1439          *
1440          *      Now it will return ENETDOWN, if device have just gone down,
1441          *      but then it will block.
1442          */
1443 
1444         skb=skb_recv_datagram(sk,flags,flags&MSG_DONTWAIT,&err);
1445 
1446         /*
1447          *      An error occurred so return it. Because skb_recv_datagram()
1448          *      handles the blocking we don't see and worry about blocking
1449          *      retries.
1450          */
1451 
1452         if (skb == NULL)
1453                 goto out;
1454 
1455         /*
1456          *      If the address length field is there to be filled in, we fill
1457          *      it in now.
1458          */
1459 
1460         sll = &PACKET_SKB_CB(skb)->sa.ll;
1461         if (sock->type == SOCK_PACKET)
1462                 msg->msg_namelen = sizeof(struct sockaddr_pkt);
1463         else
1464                 msg->msg_namelen = sll->sll_halen + offsetof(struct sockaddr_ll, sll_addr);
1465 
1466         /*
1467          *      You lose any data beyond the buffer you gave. If it worries a
1468          *      user program they can ask the device for its MTU anyway.
1469          */
1470 
1471         copied = skb->len;
1472         if (copied > len)
1473         {
1474                 copied=len;
1475                 msg->msg_flags|=MSG_TRUNC;
1476         }
1477 
1478         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1479         if (err)
1480                 goto out_free;
1481 
1482         sock_recv_timestamp(msg, sk, skb);
1483 
1484         if (msg->msg_name)
1485                 memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa,
1486                        msg->msg_namelen);
1487 
1488         if (pkt_sk(sk)->auxdata) {
1489                 struct tpacket_auxdata aux;
1490 
1491                 aux.tp_status = TP_STATUS_USER;
1492                 if (skb->ip_summed == CHECKSUM_PARTIAL)
1493                         aux.tp_status |= TP_STATUS_CSUMNOTREADY;
1494                 aux.tp_len = PACKET_SKB_CB(skb)->origlen;
1495                 aux.tp_snaplen = skb->len;
1496                 aux.tp_mac = 0;
1497                 aux.tp_net = skb_network_offset(skb);
1498                 aux.tp_vlan_tci = skb->vlan_tci;
1499 
1500                 put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
1501         }
1502 
1503         /*
1504          *      Free or return the buffer as appropriate. Again this
1505          *      hides all the races and re-entrancy issues from us.
1506          */
1507         err = (flags&MSG_TRUNC) ? skb->len : copied;
1508 
1509 out_free:
1510         skb_free_datagram(sk, skb);
1511 out:
1512         return err;
1513 }
1514 
1515 static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
1516                                int *uaddr_len, int peer)
1517 {
1518         struct net_device *dev;
1519         struct sock *sk = sock->sk;
1520 
1521         if (peer)
1522                 return -EOPNOTSUPP;
1523 
1524         uaddr->sa_family = AF_PACKET;
1525         dev = dev_get_by_index(sock_net(sk), pkt_sk(sk)->ifindex);
1526         if (dev) {
1527                 strlcpy(uaddr->sa_data, dev->name, 15);
1528                 dev_put(dev);
1529         } else
1530                 memset(uaddr->sa_data, 0, 14);
1531         *uaddr_len = sizeof(*uaddr);
1532 
1533         return 0;
1534 }
1535 
1536 static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
1537                           int *uaddr_len, int peer)
1538 {
1539         struct net_device *dev;
1540         struct sock *sk = sock->sk;
1541         struct packet_sock *po = pkt_sk(sk);
1542         struct sockaddr_ll *sll = (struct sockaddr_ll*)uaddr;
1543 
1544         if (peer)
1545                 return -EOPNOTSUPP;
1546 
1547         sll->sll_family = AF_PACKET;
1548         sll->sll_ifindex = po->ifindex;
1549         sll->sll_protocol = po->num;
1550         dev = dev_get_by_index(sock_net(sk), po->ifindex);
1551         if (dev) {
1552                 sll->sll_hatype = dev->type;
1553                 sll->sll_halen = dev->addr_len;
1554                 memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
1555                 dev_put(dev);
1556         } else {
1557                 sll->sll_hatype = 0;    /* Bad: we have no ARPHRD_UNSPEC */
1558                 sll->sll_halen = 0;
1559         }
1560         *uaddr_len = offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
1561 
1562         return 0;
1563 }
1564 
1565 static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
1566                          int what)
1567 {
1568         switch (i->type) {
1569         case PACKET_MR_MULTICAST:
1570                 if (what > 0)
1571                         return dev_mc_add(dev, i->addr, i->alen, 0);
1572                 else
1573                         return dev_mc_delete(dev, i->addr, i->alen, 0);
1574                 break;
1575         case PACKET_MR_PROMISC:
1576                 return dev_set_promiscuity(dev, what);
1577                 break;
1578         case PACKET_MR_ALLMULTI:
1579                 return dev_set_allmulti(dev, what);
1580                 break;
1581         case PACKET_MR_UNICAST:
1582                 if (what > 0)
1583                         return dev_unicast_add(dev, i->addr);
1584                 else
1585                         return dev_unicast_delete(dev, i->addr);
1586                 break;
1587         default:;
1588         }
1589         return 0;
1590 }
1591 
1592 static void packet_dev_mclist(struct net_device *dev, struct packet_mclist *i, int what)
1593 {
1594         for ( ; i; i=i->next) {
1595                 if (i->ifindex == dev->ifindex)
1596                         packet_dev_mc(dev, i, what);
1597         }
1598 }
1599 
1600 static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
1601 {
1602         struct packet_sock *po = pkt_sk(sk);
1603         struct packet_mclist *ml, *i;
1604         struct net_device *dev;
1605         int err;
1606 
1607         rtnl_lock();
1608 
1609         err = -ENODEV;
1610         dev = __dev_get_by_index(sock_net(sk), mreq->mr_ifindex);
1611         if (!dev)
1612                 goto done;
1613 
1614         err = -EINVAL;
1615         if (mreq->mr_alen > dev->addr_len)
1616                 goto done;
1617 
1618         err = -ENOBUFS;
1619         i = kmalloc(sizeof(*i), GFP_KERNEL);
1620         if (i == NULL)
1621                 goto done;
1622 
1623         err = 0;
1624         for (ml = po->mclist; ml; ml = ml->next) {
1625                 if (ml->ifindex == mreq->mr_ifindex &&
1626                     ml->type == mreq->mr_type &&
1627                     ml->alen == mreq->mr_alen &&
1628                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
1629                         ml->count++;
1630                         /* Free the new element ... */
1631                         kfree(i);
1632                         goto done;
1633                 }
1634         }
1635 
1636         i->type = mreq->mr_type;
1637         i->ifindex = mreq->mr_ifindex;
1638         i->alen = mreq->mr_alen;
1639         memcpy(i->addr, mreq->mr_address, i->alen);
1640         i->count = 1;
1641         i->next = po->mclist;
1642         po->mclist = i;
1643         err = packet_dev_mc(dev, i, 1);
1644         if (err) {
1645                 po->mclist = i->next;
1646                 kfree(i);
1647         }
1648 
1649 done:
1650         rtnl_unlock();
1651         return err;
1652 }
1653 
1654 static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
1655 {
1656         struct packet_mclist *ml, **mlp;
1657 
1658         rtnl_lock();
1659 
1660         for (mlp = &pkt_sk(sk)->mclist; (ml = *mlp) != NULL; mlp = &ml->next) {
1661                 if (ml->ifindex == mreq->mr_ifindex &&
1662                     ml->type == mreq->mr_type &&
1663                     ml->alen == mreq->mr_alen &&
1664                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
1665                         if (--ml->count == 0) {
1666                                 struct net_device *dev;
1667                                 *mlp = ml->next;
1668                                 dev = dev_get_by_index(sock_net(sk), ml->ifindex);
1669                                 if (dev) {
1670                                         packet_dev_mc(dev, ml, -1);
1671                                         dev_put(dev);
1672                                 }
1673                                 kfree(ml);
1674                         }
1675                         rtnl_unlock();
1676                         return 0;
1677                 }
1678         }
1679         rtnl_unlock();
1680         return -EADDRNOTAVAIL;
1681 }
1682 
1683 static void packet_flush_mclist(struct sock *sk)
1684 {
1685         struct packet_sock *po = pkt_sk(sk);
1686         struct packet_mclist *ml;
1687 
1688         if (!po->mclist)
1689                 return;
1690 
1691         rtnl_lock();
1692         while ((ml = po->mclist) != NULL) {
1693                 struct net_device *dev;
1694 
1695                 po->mclist = ml->next;
1696                 if ((dev = dev_get_by_index(sock_net(sk), ml->ifindex)) != NULL) {
1697                         packet_dev_mc(dev, ml, -1);
1698                         dev_put(dev);
1699                 }
1700                 kfree(ml);
1701         }
1702         rtnl_unlock();
1703 }
1704 
1705 static int
1706 packet_setsockopt(struct socket *sock, int level, int optname, char __user *optval, int optlen)
1707 {
1708         struct sock *sk = sock->sk;
1709         struct packet_sock *po = pkt_sk(sk);
1710         int ret;
1711 
1712         if (level != SOL_PACKET)
1713                 return -ENOPROTOOPT;
1714 
1715         switch (optname) {
1716         case PACKET_ADD_MEMBERSHIP:
1717         case PACKET_DROP_MEMBERSHIP:
1718         {
1719                 struct packet_mreq_max mreq;
1720                 int len = optlen;
1721                 memset(&mreq, 0, sizeof(mreq));
1722                 if (len < sizeof(struct packet_mreq))
1723                         return -EINVAL;
1724                 if (len > sizeof(mreq))
1725                         len = sizeof(mreq);
1726                 if (copy_from_user(&mreq,optval,len))
1727                         return -EFAULT;
1728                 if (len < (mreq.mr_alen + offsetof(struct packet_mreq, mr_address)))
1729                         return -EINVAL;
1730                 if (optname == PACKET_ADD_MEMBERSHIP)
1731                         ret = packet_mc_add(sk, &mreq);
1732                 else
1733                         ret = packet_mc_drop(sk, &mreq);
1734                 return ret;
1735         }
1736 
1737 #ifdef CONFIG_PACKET_MMAP
1738         case PACKET_RX_RING:
1739         case PACKET_TX_RING:
1740         {
1741                 struct tpacket_req req;
1742 
1743                 if (optlen<sizeof(req))
1744                         return -EINVAL;
1745                 if (copy_from_user(&req,optval,sizeof(req)))
1746                         return -EFAULT;
1747                 return packet_set_ring(sk, &req, 0, optname == PACKET_TX_RING);
1748         }
1749         case PACKET_COPY_THRESH:
1750         {
1751                 int val;
1752 
1753                 if (optlen!=sizeof(val))
1754                         return -EINVAL;
1755                 if (copy_from_user(&val,optval,sizeof(val)))
1756                         return -EFAULT;
1757 
1758                 pkt_sk(sk)->copy_thresh = val;
1759                 return 0;
1760         }
1761         case PACKET_VERSION:
1762         {
1763                 int val;
1764 
1765                 if (optlen != sizeof(val))
1766                         return -EINVAL;
1767                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
1768                         return -EBUSY;
1769                 if (copy_from_user(&val, optval, sizeof(val)))
1770                         return -EFAULT;
1771                 switch (val) {
1772                 case TPACKET_V1:
1773                 case TPACKET_V2:
1774                         po->tp_version = val;
1775                         return 0;
1776                 default:
1777                         return -EINVAL;
1778                 }
1779         }
1780         case PACKET_RESERVE:
1781         {
1782                 unsigned int val;
1783 
1784                 if (optlen != sizeof(val))
1785                         return -EINVAL;
1786                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
1787                         return -EBUSY;
1788                 if (copy_from_user(&val, optval, sizeof(val)))
1789                         return -EFAULT;
1790                 po->tp_reserve = val;
1791                 return 0;
1792         }
1793         case PACKET_LOSS:
1794         {
1795                 unsigned int val;
1796 
1797                 if (optlen != sizeof(val))
1798                         return -EINVAL;
1799                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
1800                         return -EBUSY;
1801                 if (copy_from_user(&val, optval, sizeof(val)))
1802                         return -EFAULT;
1803                 po->tp_loss = !!val;
1804                 return 0;
1805         }
1806 #endif
1807         case PACKET_AUXDATA:
1808         {
1809                 int val;
1810 
1811                 if (optlen < sizeof(val))
1812                         return -EINVAL;
1813                 if (copy_from_user(&val, optval, sizeof(val)))
1814                         return -EFAULT;
1815 
1816                 po->auxdata = !!val;
1817                 return 0;
1818         }
1819         case PACKET_ORIGDEV:
1820         {
1821                 int val;
1822 
1823                 if (optlen < sizeof(val))
1824                         return -EINVAL;
1825                 if (copy_from_user(&val, optval, sizeof(val)))
1826                         return -EFAULT;
1827 
1828                 po->origdev = !!val;
1829                 return 0;
1830         }
1831         default:
1832                 return -ENOPROTOOPT;
1833         }
1834 }
1835 
1836 static int packet_getsockopt(struct socket *sock, int level, int optname,
1837                              char __user *optval, int __user *optlen)
1838 {
1839         unsigned int len;
1840         int val;
1841         struct sock *sk = sock->sk;
1842         struct packet_sock *po = pkt_sk(sk);
1843         void *data;
1844         struct tpacket_stats st;
1845 
1846         if (level != SOL_PACKET)
1847                 return -ENOPROTOOPT;
1848 
1849         if (get_user(len, optlen))
1850                 return -EFAULT;
1851 
1852         if ((int)len < 0)
1853                 return -EINVAL;
1854 
1855         switch (optname) {
1856         case PACKET_STATISTICS:
1857                 if (len > sizeof(struct tpacket_stats))
1858                         len = sizeof(struct tpacket_stats);
1859                 spin_lock_bh(&sk->sk_receive_queue.lock);
1860                 st = po->stats;
1861                 memset(&po->stats, 0, sizeof(st));
1862                 spin_unlock_bh(&sk->sk_receive_queue.lock);
1863                 st.tp_packets += st.tp_drops;
1864 
1865                 data = &st;
1866                 break;
1867         case PACKET_AUXDATA:
1868                 if (len > sizeof(int))
1869                         len = sizeof(int);
1870                 val = po->auxdata;
1871 
1872                 data = &val;
1873                 break;
1874         case PACKET_ORIGDEV:
1875                 if (len > sizeof(int))
1876                         len = sizeof(int);
1877                 val = po->origdev;
1878 
1879                 data = &val;
1880                 break;
1881 #ifdef CONFIG_PACKET_MMAP
1882         case PACKET_VERSION:
1883                 if (len > sizeof(int))
1884                         len = sizeof(int);
1885                 val = po->tp_version;
1886                 data = &val;
1887                 break;
1888         case PACKET_HDRLEN:
1889                 if (len > sizeof(int))
1890                         len = sizeof(int);
1891                 if (copy_from_user(&val, optval, len))
1892                         return -EFAULT;
1893                 switch (val) {
1894                 case TPACKET_V1:
1895                         val = sizeof(struct tpacket_hdr);
1896                         break;
1897                 case TPACKET_V2:
1898                         val = sizeof(struct tpacket2_hdr);
1899                         break;
1900                 default:
1901                         return -EINVAL;
1902                 }
1903                 data = &val;
1904                 break;
1905         case PACKET_RESERVE:
1906                 if (len > sizeof(unsigned int))
1907                         len = sizeof(unsigned int);
1908                 val = po->tp_reserve;
1909                 data = &val;
1910                 break;
1911         case PACKET_LOSS:
1912                 if (len > sizeof(unsigned int))
1913                         len = sizeof(unsigned int);
1914                 val = po->tp_loss;
1915                 data = &val;
1916                 break;
1917 #endif
1918         default:
1919                 return -ENOPROTOOPT;
1920         }
1921 
1922         if (put_user(len, optlen))
1923                 return -EFAULT;
1924         if (copy_to_user(optval, data, len))
1925                 return -EFAULT;
1926         return 0;
1927 }
1928 
1929 
1930 static int packet_notifier(struct notifier_block *this, unsigned long msg, void *data)
1931 {
1932         struct sock *sk;
1933         struct hlist_node *node;
1934         struct net_device *dev = data;
1935         struct net *net = dev_net(dev);
1936 
1937         read_lock(&net->packet.sklist_lock);
1938         sk_for_each(sk, node, &net->packet.sklist) {
1939                 struct packet_sock *po = pkt_sk(sk);
1940 
1941                 switch (msg) {
1942                 case NETDEV_UNREGISTER:
1943                         if (po->mclist)
1944                                 packet_dev_mclist(dev, po->mclist, -1);
1945                         /* fallthrough */
1946 
1947                 case NETDEV_DOWN:
1948                         if (dev->ifindex == po->ifindex) {
1949                                 spin_lock(&po->bind_lock);
1950                                 if (po->running) {
1951                                         __dev_remove_pack(&po->prot_hook);
1952                                         __sock_put(sk);
1953                                         po->running = 0;
1954                                         sk->sk_err = ENETDOWN;
1955                                         if (!sock_flag(sk, SOCK_DEAD))
1956                                                 sk->sk_error_report(sk);
1957                                 }
1958                                 if (msg == NETDEV_UNREGISTER) {
1959                                         po->ifindex = -1;
1960                                         po->prot_hook.dev = NULL;
1961                                 }
1962                                 spin_unlock(&po->bind_lock);
1963                         }
1964                         break;
1965                 case NETDEV_UP:
1966                         spin_lock(&po->bind_lock);
1967                         if (dev->ifindex == po->ifindex && po->num &&
1968                             !po->running) {
1969                                 dev_add_pack(&po->prot_hook);
1970                                 sock_hold(sk);
1971                                 po->running = 1;
1972                         }
1973                         spin_unlock(&po->bind_lock);
1974                         break;
1975                 }
1976         }
1977         read_unlock(&net->packet.sklist_lock);
1978         return NOTIFY_DONE;
1979 }
1980 
1981 
1982 static int packet_ioctl(struct socket *sock, unsigned int cmd,
1983                         unsigned long arg)
1984 {
1985         struct sock *sk = sock->sk;
1986 
1987         switch (cmd) {
1988                 case SIOCOUTQ:
1989                 {
1990                         int amount = sk_wmem_alloc_get(sk);
1991 
1992                         return put_user(amount, (int __user *)arg);
1993                 }
1994                 case SIOCINQ:
1995                 {
1996                         struct sk_buff *skb;
1997                         int amount = 0;
1998 
1999                         spin_lock_bh(&sk->sk_receive_queue.lock);
2000                         skb = skb_peek(&sk->sk_receive_queue);
2001                         if (skb)
2002                                 amount = skb->len;
2003                         spin_unlock_bh(&sk->sk_receive_queue.lock);
2004                         return put_user(amount, (int __user *)arg);
2005                 }
2006                 case SIOCGSTAMP:
2007                         return sock_get_timestamp(sk, (struct timeval __user *)arg);
2008                 case SIOCGSTAMPNS:
2009                         return sock_get_timestampns(sk, (struct timespec __user *)arg);
2010 
2011 #ifdef CONFIG_INET
2012                 case SIOCADDRT:
2013                 case SIOCDELRT:
2014                 case SIOCDARP:
2015                 case SIOCGARP:
2016                 case SIOCSARP:
2017                 case SIOCGIFADDR:
2018                 case SIOCSIFADDR:
2019                 case SIOCGIFBRDADDR:
2020                 case SIOCSIFBRDADDR:
2021                 case SIOCGIFNETMASK:
2022                 case SIOCSIFNETMASK:
2023                 case SIOCGIFDSTADDR:
2024                 case SIOCSIFDSTADDR:
2025                 case SIOCSIFFLAGS:
2026                         if (!net_eq(sock_net(sk), &init_net))
2027                                 return -ENOIOCTLCMD;
2028                         return inet_dgram_ops.ioctl(sock, cmd, arg);
2029 #endif
2030 
2031                 default:
2032                         return -ENOIOCTLCMD;
2033         }
2034         return 0;
2035 }
2036 
2037 #ifndef CONFIG_PACKET_MMAP
2038 #define packet_mmap sock_no_mmap
2039 #define packet_poll datagram_poll
2040 #else
2041 
2042 static unsigned int packet_poll(struct file * file, struct socket *sock,
2043                                 poll_table *wait)
2044 {
2045         struct sock *sk = sock->sk;
2046         struct packet_sock *po = pkt_sk(sk);
2047         unsigned int mask = datagram_poll(file, sock, wait);
2048 
2049         spin_lock_bh(&sk->sk_receive_queue.lock);
2050         if (po->rx_ring.pg_vec) {
2051                 if (!packet_previous_frame(po, &po->rx_ring, TP_STATUS_KERNEL))
2052                         mask |= POLLIN | POLLRDNORM;
2053         }
2054         spin_unlock_bh(&sk->sk_receive_queue.lock);
2055         spin_lock_bh(&sk->sk_write_queue.lock);
2056         if (po->tx_ring.pg_vec) {
2057                 if (packet_current_frame(po, &po->tx_ring, TP_STATUS_AVAILABLE))
2058                         mask |= POLLOUT | POLLWRNORM;
2059         }
2060         spin_unlock_bh(&sk->sk_write_queue.lock);
2061         return mask;
2062 }
2063 
2064 
2065 /* Dirty? Well, I still did not learn better way to account
2066  * for user mmaps.
2067  */
2068 
2069 static void packet_mm_open(struct vm_area_struct *vma)
2070 {
2071         struct file *file = vma->vm_file;
2072         struct socket * sock = file->private_data;
2073         struct sock *sk = sock->sk;
2074 
2075         if (sk)
2076                 atomic_inc(&pkt_sk(sk)->mapped);
2077 }
2078 
2079 static void packet_mm_close(struct vm_area_struct *vma)
2080 {
2081         struct file *file = vma->vm_file;
2082         struct socket * sock = file->private_data;
2083         struct sock *sk = sock->sk;
2084 
2085         if (sk)
2086                 atomic_dec(&pkt_sk(sk)->mapped);
2087 }
2088 
2089 static struct vm_operations_struct packet_mmap_ops = {
2090         .open = packet_mm_open,
2091         .close =packet_mm_close,
2092 };
2093 
2094 static void free_pg_vec(char **pg_vec, unsigned int order, unsigned int len)
2095 {
2096         int i;
2097 
2098         for (i = 0; i < len; i++) {
2099                 if (likely(pg_vec[i]))
2100                         free_pages((unsigned long) pg_vec[i], order);
2101         }
2102         kfree(pg_vec);
2103 }
2104 
2105 static inline char *alloc_one_pg_vec_page(unsigned long order)
2106 {
2107         gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO | __GFP_NOWARN;
2108 
2109         return (char *) __get_free_pages(gfp_flags, order);
2110 }
2111 
2112 static char **alloc_pg_vec(struct tpacket_req *req, int order)
2113 {
2114         unsigned int block_nr = req->tp_block_nr;
2115         char **pg_vec;
2116         int i;
2117 
2118         pg_vec = kzalloc(block_nr * sizeof(char *), GFP_KERNEL);
2119         if (unlikely(!pg_vec))
2120                 goto out;
2121 
2122         for (i = 0; i < block_nr; i++) {
2123                 pg_vec[i] = alloc_one_pg_vec_page(order);
2124                 if (unlikely(!pg_vec[i]))
2125                         goto out_free_pgvec;
2126         }
2127 
2128 out:
2129         return pg_vec;
2130 
2131 out_free_pgvec:
2132         free_pg_vec(pg_vec, order, block_nr);
2133         pg_vec = NULL;
2134         goto out;
2135 }
2136 
2137 static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
2138                 int closing, int tx_ring)
2139 {
2140         char **pg_vec = NULL;
2141         struct packet_sock *po = pkt_sk(sk);
2142         int was_running, order = 0;
2143         struct packet_ring_buffer *rb;
2144         struct sk_buff_head *rb_queue;
2145         __be16 num;
2146         int err;
2147 
2148         rb = tx_ring ? &po->tx_ring : &po->rx_ring;
2149         rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
2150 
2151         err = -EBUSY;
2152         if (!closing) {
2153                 if (atomic_read(&po->mapped))
2154                         goto out;
2155                 if (atomic_read(&rb->pending))
2156                         goto out;
2157         }
2158 
2159         if (req->tp_block_nr) {
2160                 /* Sanity tests and some calculations */
2161                 err = -EBUSY;
2162                 if (unlikely(rb->pg_vec))
2163                         goto out;
2164 
2165                 switch (po->tp_version) {
2166                 case TPACKET_V1:
2167                         po->tp_hdrlen = TPACKET_HDRLEN;
2168                         break;
2169                 case TPACKET_V2:
2170                         po->tp_hdrlen = TPACKET2_HDRLEN;
2171                         break;
2172                 }
2173 
2174                 err = -EINVAL;
2175                 if (unlikely((int)req->tp_block_size <= 0))
2176                         goto out;
2177                 if (unlikely(req->tp_block_size & (PAGE_SIZE - 1)))
2178                         goto out;
2179                 if (unlikely(req->tp_frame_size < po->tp_hdrlen +
2180                                         po->tp_reserve))
2181                         goto out;
2182                 if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
2183                         goto out;
2184 
2185                 rb->frames_per_block = req->tp_block_size/req->tp_frame_size;
2186                 if (unlikely(rb->frames_per_block <= 0))
2187                         goto out;
2188                 if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
2189                                         req->tp_frame_nr))
2190                         goto out;
2191 
2192                 err = -ENOMEM;
2193                 order = get_order(req->tp_block_size);
2194                 pg_vec = alloc_pg_vec(req, order);
2195                 if (unlikely(!pg_vec))
2196                         goto out;
2197         }
2198         /* Done */
2199         else {
2200                 err = -EINVAL;
2201                 if (unlikely(req->tp_frame_nr))
2202                         goto out;
2203         }
2204 
2205         lock_sock(sk);
2206 
2207         /* Detach socket from network */
2208         spin_lock(&po->bind_lock);
2209         was_running = po->running;
2210         num = po->num;
2211         if (was_running) {
2212                 __dev_remove_pack(&po->prot_hook);
2213                 po->num = 0;
2214                 po->running = 0;
2215                 __sock_put(sk);
2216         }
2217         spin_unlock(&po->bind_lock);
2218 
2219         synchronize_net();
2220 
2221         err = -EBUSY;
2222         mutex_lock(&po->pg_vec_lock);
2223         if (closing || atomic_read(&po->mapped) == 0) {
2224                 err = 0;
2225 #define XC(a, b) ({ __typeof__ ((a)) __t; __t = (a); (a) = (b); __t; })
2226                 spin_lock_bh(&rb_queue->lock);
2227                 pg_vec = XC(rb->pg_vec, pg_vec);
2228                 rb->frame_max = (req->tp_frame_nr - 1);
2229                 rb->head = 0;
2230                 rb->frame_size = req->tp_frame_size;
2231                 spin_unlock_bh(&rb_queue->lock);
2232 
2233                 order = XC(rb->pg_vec_order, order);
2234                 req->tp_block_nr = XC(rb->pg_vec_len, req->tp_block_nr);
2235 
2236                 rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
2237                 po->prot_hook.func = (po->rx_ring.pg_vec) ?
2238                                                 tpacket_rcv : packet_rcv;
2239                 skb_queue_purge(rb_queue);
2240 #undef XC
2241                 if (atomic_read(&po->mapped))
2242                         printk(KERN_DEBUG "packet_mmap: vma is busy: %d\n",
2243                                                 atomic_read(&po->mapped));
2244         }
2245         mutex_unlock(&po->pg_vec_lock);
2246 
2247         spin_lock(&po->bind_lock);
2248         if (was_running && !po->running) {
2249                 sock_hold(sk);
2250                 po->running = 1;
2251                 po->num = num;
2252                 dev_add_pack(&po->prot_hook);
2253         }
2254         spin_unlock(&po->bind_lock);
2255 
2256         release_sock(sk);
2257 
2258         if (pg_vec)
2259                 free_pg_vec(pg_vec, order, req->tp_block_nr);
2260 out:
2261         return err;
2262 }
2263 
2264 static int packet_mmap(struct file *file, struct socket *sock,
2265                 struct vm_area_struct *vma)
2266 {
2267         struct sock *sk = sock->sk;
2268         struct packet_sock *po = pkt_sk(sk);
2269         unsigned long size, expected_size;
2270         struct packet_ring_buffer *rb;
2271         unsigned long start;
2272         int err = -EINVAL;
2273         int i;
2274 
2275         if (vma->vm_pgoff)
2276                 return -EINVAL;
2277 
2278         mutex_lock(&po->pg_vec_lock);
2279 
2280         expected_size = 0;
2281         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
2282                 if (rb->pg_vec) {
2283                         expected_size += rb->pg_vec_len
2284                                                 * rb->pg_vec_pages
2285                                                 * PAGE_SIZE;
2286                 }
2287         }
2288 
2289         if (expected_size == 0)
2290                 goto out;
2291 
2292         size = vma->vm_end - vma->vm_start;
2293         if (size != expected_size)
2294                 goto out;
2295 
2296         start = vma->vm_start;
2297         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
2298                 if (rb->pg_vec == NULL)
2299                         continue;
2300 
2301                 for (i = 0; i < rb->pg_vec_len; i++) {
2302                         struct page *page = virt_to_page(rb->pg_vec[i]);
2303                         int pg_num;
2304 
2305                         for (pg_num = 0; pg_num < rb->pg_vec_pages;
2306                                         pg_num++,page++) {
2307                                 err = vm_insert_page(vma, start, page);
2308                                 if (unlikely(err))
2309                                         goto out;
2310                                 start += PAGE_SIZE;
2311                         }
2312                 }
2313         }
2314 
2315         atomic_inc(&po->mapped);
2316         vma->vm_ops = &packet_mmap_ops;
2317         err = 0;
2318 
2319 out:
2320         mutex_unlock(&po->pg_vec_lock);
2321         return err;
2322 }
2323 #endif
2324 
2325 
2326 static const struct proto_ops packet_ops_spkt = {
2327         .family =       PF_PACKET,
2328         .owner =        THIS_MODULE,
2329         .release =      packet_release,
2330         .bind =         packet_bind_spkt,
2331         .connect =      sock_no_connect,
2332         .socketpair =   sock_no_socketpair,
2333         .accept =       sock_no_accept,
2334         .getname =      packet_getname_spkt,
2335         .poll =         datagram_poll,
2336         .ioctl =        packet_ioctl,
2337         .listen =       sock_no_listen,
2338         .shutdown =     sock_no_shutdown,
2339         .setsockopt =   sock_no_setsockopt,
2340         .getsockopt =   sock_no_getsockopt,
2341         .sendmsg =      packet_sendmsg_spkt,
2342         .recvmsg =      packet_recvmsg,
2343         .mmap =         sock_no_mmap,
2344         .sendpage =     sock_no_sendpage,
2345 };
2346 
2347 static const struct proto_ops packet_ops = {
2348         .family =       PF_PACKET,
2349         .owner =        THIS_MODULE,
2350         .release =      packet_release,
2351         .bind =         packet_bind,
2352         .connect =      sock_no_connect,
2353         .socketpair =   sock_no_socketpair,
2354         .accept =       sock_no_accept,
2355         .getname =      packet_getname,
2356         .poll =         packet_poll,
2357         .ioctl =        packet_ioctl,
2358         .listen =       sock_no_listen,
2359         .shutdown =     sock_no_shutdown,
2360         .setsockopt =   packet_setsockopt,
2361         .getsockopt =   packet_getsockopt,
2362         .sendmsg =      packet_sendmsg,
2363         .recvmsg =      packet_recvmsg,
2364         .mmap =         packet_mmap,
2365         .sendpage =     sock_no_sendpage,
2366 };
2367 
2368 static struct net_proto_family packet_family_ops = {
2369         .family =       PF_PACKET,
2370         .create =       packet_create,
2371         .owner  =       THIS_MODULE,
2372 };
2373 
2374 static struct notifier_block packet_netdev_notifier = {
2375         .notifier_call =packet_notifier,
2376 };
2377 
2378 #ifdef CONFIG_PROC_FS
2379 static inline struct sock *packet_seq_idx(struct net *net, loff_t off)
2380 {
2381         struct sock *s;
2382         struct hlist_node *node;
2383 
2384         sk_for_each(s, node, &net->packet.sklist) {
2385                 if (!off--)
2386                         return s;
2387         }
2388         return NULL;
2389 }
2390 
2391 static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
2392         __acquires(seq_file_net(seq)->packet.sklist_lock)
2393 {
2394         struct net *net = seq_file_net(seq);
2395         read_lock(&net->packet.sklist_lock);
2396         return *pos ? packet_seq_idx(net, *pos - 1) : SEQ_START_TOKEN;
2397 }
2398 
2399 static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2400 {
2401         struct net *net = seq_file_net(seq);
2402         ++*pos;
2403         return  (v == SEQ_START_TOKEN)
2404                 ? sk_head(&net->packet.sklist)
2405                 : sk_next((struct sock*)v) ;
2406 }
2407 
2408 static void packet_seq_stop(struct seq_file *seq, void *v)
2409         __releases(seq_file_net(seq)->packet.sklist_lock)
2410 {
2411         struct net *net = seq_file_net(seq);
2412         read_unlock(&net->packet.sklist_lock);
2413 }
2414 
2415 static int packet_seq_show(struct seq_file *seq, void *v)
2416 {
2417         if (v == SEQ_START_TOKEN)
2418                 seq_puts(seq, "sk       RefCnt Type Proto  Iface R Rmem   User   Inode\n");
2419         else {
2420                 struct sock *s = v;
2421                 const struct packet_sock *po = pkt_sk(s);
2422 
2423                 seq_printf(seq,
2424                            "%p %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
2425                            s,
2426                            atomic_read(&s->sk_refcnt),
2427                            s->sk_type,
2428                            ntohs(po->num),
2429                            po->ifindex,
2430                            po->running,
2431                            atomic_read(&s->sk_rmem_alloc),
2432                            sock_i_uid(s),
2433                            sock_i_ino(s) );
2434         }
2435 
2436         return 0;
2437 }
2438 
2439 static const struct seq_operations packet_seq_ops = {
2440         .start  = packet_seq_start,
2441         .next   = packet_seq_next,
2442         .stop   = packet_seq_stop,
2443         .show   = packet_seq_show,
2444 };
2445 
2446 static int packet_seq_open(struct inode *inode, struct file *file)
2447 {
2448         return seq_open_net(inode, file, &packet_seq_ops,
2449                             sizeof(struct seq_net_private));
2450 }
2451 
2452 static const struct file_operations packet_seq_fops = {
2453         .owner          = THIS_MODULE,
2454         .open           = packet_seq_open,
2455         .read           = seq_read,
2456         .llseek         = seq_lseek,
2457         .release        = seq_release_net,
2458 };
2459 
2460 #endif
2461 
2462 static int packet_net_init(struct net *net)
2463 {
2464         rwlock_init(&net->packet.sklist_lock);
2465         INIT_HLIST_HEAD(&net->packet.sklist);
2466 
2467         if (!proc_net_fops_create(net, "packet", 0, &packet_seq_fops))
2468                 return -ENOMEM;
2469 
2470         return 0;
2471 }
2472 
2473 static void packet_net_exit(struct net *net)
2474 {
2475         proc_net_remove(net, "packet");
2476 }
2477 
2478 static struct pernet_operations packet_net_ops = {
2479         .init = packet_net_init,
2480         .exit = packet_net_exit,
2481 };
2482 
2483 
2484 static void __exit packet_exit(void)
2485 {
2486         unregister_netdevice_notifier(&packet_netdev_notifier);
2487         unregister_pernet_subsys(&packet_net_ops);
2488         sock_unregister(PF_PACKET);
2489         proto_unregister(&packet_proto);
2490 }
2491 
2492 static int __init packet_init(void)
2493 {
2494         int rc = proto_register(&packet_proto, 0);
2495 
2496         if (rc != 0)
2497                 goto out;
2498 
2499         sock_register(&packet_family_ops);
2500         register_pernet_subsys(&packet_net_ops);
2501         register_netdevice_notifier(&packet_netdev_notifier);
2502 out:
2503         return rc;
2504 }
2505 
2506 module_init(packet_init);
2507 module_exit(packet_exit);
2508 MODULE_LICENSE("GPL");
2509 MODULE_ALIAS_NETPROTO(PF_PACKET);
2510 
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