Merge branch 'drm-patches' of master.kernel.org:/pub/scm/linux/kernel/git/airlied...
[linux-2.6] / net / core / netpoll.c
1 /*
2  * Common framework for low-level network console, dump, and debugger code
3  *
4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
5  *
6  * based on the netconsole code from:
7  *
8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
9  * Copyright (C) 2002  Red Hat, Inc.
10  */
11
12 #include <linux/netdevice.h>
13 #include <linux/etherdevice.h>
14 #include <linux/string.h>
15 #include <linux/if_arp.h>
16 #include <linux/inetdevice.h>
17 #include <linux/inet.h>
18 #include <linux/interrupt.h>
19 #include <linux/netpoll.h>
20 #include <linux/sched.h>
21 #include <linux/delay.h>
22 #include <linux/rcupdate.h>
23 #include <linux/workqueue.h>
24 #include <net/tcp.h>
25 #include <net/udp.h>
26 #include <asm/unaligned.h>
27
28 /*
29  * We maintain a small pool of fully-sized skbs, to make sure the
30  * message gets out even in extreme OOM situations.
31  */
32
33 #define MAX_UDP_CHUNK 1460
34 #define MAX_SKBS 32
35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
36
37 static struct sk_buff_head skb_pool;
38
39 static atomic_t trapped;
40
41 #define USEC_PER_POLL   50
42 #define NETPOLL_RX_ENABLED  1
43 #define NETPOLL_RX_DROP     2
44
45 #define MAX_SKB_SIZE \
46                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
47                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
48
49 static void zap_completion_queue(void);
50 static void arp_reply(struct sk_buff *skb);
51
52 static void queue_process(struct work_struct *work)
53 {
54         struct netpoll_info *npinfo =
55                 container_of(work, struct netpoll_info, tx_work.work);
56         struct sk_buff *skb;
57         unsigned long flags;
58
59         while ((skb = skb_dequeue(&npinfo->txq))) {
60                 struct net_device *dev = skb->dev;
61
62                 if (!netif_device_present(dev) || !netif_running(dev)) {
63                         __kfree_skb(skb);
64                         continue;
65                 }
66
67                 local_irq_save(flags);
68                 netif_tx_lock(dev);
69                 if (netif_queue_stopped(dev) ||
70                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
71                         skb_queue_head(&npinfo->txq, skb);
72                         netif_tx_unlock(dev);
73                         local_irq_restore(flags);
74
75                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
76                         return;
77                 }
78                 netif_tx_unlock(dev);
79                 local_irq_restore(flags);
80         }
81 }
82
83 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
84                             unsigned short ulen, __be32 saddr, __be32 daddr)
85 {
86         __wsum psum;
87
88         if (uh->check == 0 || skb_csum_unnecessary(skb))
89                 return 0;
90
91         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
92
93         if (skb->ip_summed == CHECKSUM_COMPLETE &&
94             !csum_fold(csum_add(psum, skb->csum)))
95                 return 0;
96
97         skb->csum = psum;
98
99         return __skb_checksum_complete(skb);
100 }
101
102 /*
103  * Check whether delayed processing was scheduled for our NIC. If so,
104  * we attempt to grab the poll lock and use ->poll() to pump the card.
105  * If this fails, either we've recursed in ->poll() or it's already
106  * running on another CPU.
107  *
108  * Note: we don't mask interrupts with this lock because we're using
109  * trylock here and interrupts are already disabled in the softirq
110  * case. Further, we test the poll_owner to avoid recursion on UP
111  * systems where the lock doesn't exist.
112  *
113  * In cases where there is bi-directional communications, reading only
114  * one message at a time can lead to packets being dropped by the
115  * network adapter, forcing superfluous retries and possibly timeouts.
116  * Thus, we set our budget to greater than 1.
117  */
118 static void poll_napi(struct netpoll *np)
119 {
120         struct netpoll_info *npinfo = np->dev->npinfo;
121         int budget = 16;
122
123         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
124             npinfo->poll_owner != smp_processor_id() &&
125             spin_trylock(&npinfo->poll_lock)) {
126                 npinfo->rx_flags |= NETPOLL_RX_DROP;
127                 atomic_inc(&trapped);
128
129                 np->dev->poll(np->dev, &budget);
130
131                 atomic_dec(&trapped);
132                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
133                 spin_unlock(&npinfo->poll_lock);
134         }
135 }
136
137 static void service_arp_queue(struct netpoll_info *npi)
138 {
139         struct sk_buff *skb;
140
141         if (unlikely(!npi))
142                 return;
143
144         skb = skb_dequeue(&npi->arp_tx);
145
146         while (skb != NULL) {
147                 arp_reply(skb);
148                 skb = skb_dequeue(&npi->arp_tx);
149         }
150 }
151
152 void netpoll_poll(struct netpoll *np)
153 {
154         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
155                 return;
156
157         /* Process pending work on NIC */
158         np->dev->poll_controller(np->dev);
159         if (np->dev->poll)
160                 poll_napi(np);
161
162         service_arp_queue(np->dev->npinfo);
163
164         zap_completion_queue();
165 }
166
167 static void refill_skbs(void)
168 {
169         struct sk_buff *skb;
170         unsigned long flags;
171
172         spin_lock_irqsave(&skb_pool.lock, flags);
173         while (skb_pool.qlen < MAX_SKBS) {
174                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
175                 if (!skb)
176                         break;
177
178                 __skb_queue_tail(&skb_pool, skb);
179         }
180         spin_unlock_irqrestore(&skb_pool.lock, flags);
181 }
182
183 static void zap_completion_queue(void)
184 {
185         unsigned long flags;
186         struct softnet_data *sd = &get_cpu_var(softnet_data);
187
188         if (sd->completion_queue) {
189                 struct sk_buff *clist;
190
191                 local_irq_save(flags);
192                 clist = sd->completion_queue;
193                 sd->completion_queue = NULL;
194                 local_irq_restore(flags);
195
196                 while (clist != NULL) {
197                         struct sk_buff *skb = clist;
198                         clist = clist->next;
199                         if (skb->destructor)
200                                 dev_kfree_skb_any(skb); /* put this one back */
201                         else
202                                 __kfree_skb(skb);
203                 }
204         }
205
206         put_cpu_var(softnet_data);
207 }
208
209 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
210 {
211         int count = 0;
212         struct sk_buff *skb;
213
214         zap_completion_queue();
215         refill_skbs();
216 repeat:
217
218         skb = alloc_skb(len, GFP_ATOMIC);
219         if (!skb)
220                 skb = skb_dequeue(&skb_pool);
221
222         if (!skb) {
223                 if (++count < 10) {
224                         netpoll_poll(np);
225                         goto repeat;
226                 }
227                 return NULL;
228         }
229
230         atomic_set(&skb->users, 1);
231         skb_reserve(skb, reserve);
232         return skb;
233 }
234
235 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
236 {
237         int status = NETDEV_TX_BUSY;
238         unsigned long tries;
239         struct net_device *dev = np->dev;
240         struct netpoll_info *npinfo = np->dev->npinfo;
241
242         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
243                 __kfree_skb(skb);
244                 return;
245         }
246
247         /* don't get messages out of order, and no recursion */
248         if (skb_queue_len(&npinfo->txq) == 0 &&
249                     npinfo->poll_owner != smp_processor_id()) {
250                 unsigned long flags;
251
252                 local_irq_save(flags);
253                 if (netif_tx_trylock(dev)) {
254                         /* try until next clock tick */
255                         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
256                                         tries > 0; --tries) {
257                                 if (!netif_queue_stopped(dev))
258                                         status = dev->hard_start_xmit(skb, dev);
259
260                                 if (status == NETDEV_TX_OK)
261                                         break;
262
263                                 /* tickle device maybe there is some cleanup */
264                                 netpoll_poll(np);
265
266                                 udelay(USEC_PER_POLL);
267                         }
268                         netif_tx_unlock(dev);
269                 }
270                 local_irq_restore(flags);
271         }
272
273         if (status != NETDEV_TX_OK) {
274                 skb_queue_tail(&npinfo->txq, skb);
275                 schedule_delayed_work(&npinfo->tx_work,0);
276         }
277 }
278
279 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
280 {
281         int total_len, eth_len, ip_len, udp_len;
282         struct sk_buff *skb;
283         struct udphdr *udph;
284         struct iphdr *iph;
285         struct ethhdr *eth;
286
287         udp_len = len + sizeof(*udph);
288         ip_len = eth_len = udp_len + sizeof(*iph);
289         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
290
291         skb = find_skb(np, total_len, total_len - len);
292         if (!skb)
293                 return;
294
295         skb_copy_to_linear_data(skb, msg, len);
296         skb->len += len;
297
298         skb_push(skb, sizeof(*udph));
299         skb_reset_transport_header(skb);
300         udph = udp_hdr(skb);
301         udph->source = htons(np->local_port);
302         udph->dest = htons(np->remote_port);
303         udph->len = htons(udp_len);
304         udph->check = 0;
305         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
306                                         htonl(np->remote_ip),
307                                         udp_len, IPPROTO_UDP,
308                                         csum_partial((unsigned char *)udph, udp_len, 0));
309         if (udph->check == 0)
310                 udph->check = CSUM_MANGLED_0;
311
312         skb_push(skb, sizeof(*iph));
313         skb_reset_network_header(skb);
314         iph = ip_hdr(skb);
315
316         /* iph->version = 4; iph->ihl = 5; */
317         put_unaligned(0x45, (unsigned char *)iph);
318         iph->tos      = 0;
319         put_unaligned(htons(ip_len), &(iph->tot_len));
320         iph->id       = 0;
321         iph->frag_off = 0;
322         iph->ttl      = 64;
323         iph->protocol = IPPROTO_UDP;
324         iph->check    = 0;
325         put_unaligned(htonl(np->local_ip), &(iph->saddr));
326         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
327         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
328
329         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
330         skb_reset_mac_header(skb);
331         skb->protocol = eth->h_proto = htons(ETH_P_IP);
332         memcpy(eth->h_source, np->local_mac, 6);
333         memcpy(eth->h_dest, np->remote_mac, 6);
334
335         skb->dev = np->dev;
336
337         netpoll_send_skb(np, skb);
338 }
339
340 static void arp_reply(struct sk_buff *skb)
341 {
342         struct netpoll_info *npinfo = skb->dev->npinfo;
343         struct arphdr *arp;
344         unsigned char *arp_ptr;
345         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
346         __be32 sip, tip;
347         unsigned char *sha;
348         struct sk_buff *send_skb;
349         struct netpoll *np = NULL;
350
351         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
352                 np = npinfo->rx_np;
353         if (!np)
354                 return;
355
356         /* No arp on this interface */
357         if (skb->dev->flags & IFF_NOARP)
358                 return;
359
360         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
361                                  (2 * skb->dev->addr_len) +
362                                  (2 * sizeof(u32)))))
363                 return;
364
365         skb_reset_network_header(skb);
366         skb_reset_transport_header(skb);
367         arp = arp_hdr(skb);
368
369         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
370              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
371             arp->ar_pro != htons(ETH_P_IP) ||
372             arp->ar_op != htons(ARPOP_REQUEST))
373                 return;
374
375         arp_ptr = (unsigned char *)(arp+1);
376         /* save the location of the src hw addr */
377         sha = arp_ptr;
378         arp_ptr += skb->dev->addr_len;
379         memcpy(&sip, arp_ptr, 4);
380         arp_ptr += 4;
381         /* if we actually cared about dst hw addr, it would get copied here */
382         arp_ptr += skb->dev->addr_len;
383         memcpy(&tip, arp_ptr, 4);
384
385         /* Should we ignore arp? */
386         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
387                 return;
388
389         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
390         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
391                             LL_RESERVED_SPACE(np->dev));
392
393         if (!send_skb)
394                 return;
395
396         skb_reset_network_header(send_skb);
397         arp = (struct arphdr *) skb_put(send_skb, size);
398         send_skb->dev = skb->dev;
399         send_skb->protocol = htons(ETH_P_ARP);
400
401         /* Fill the device header for the ARP frame */
402
403         if (np->dev->hard_header &&
404             np->dev->hard_header(send_skb, skb->dev, ptype,
405                                  sha, np->local_mac,
406                                  send_skb->len) < 0) {
407                 kfree_skb(send_skb);
408                 return;
409         }
410
411         /*
412          * Fill out the arp protocol part.
413          *
414          * we only support ethernet device type,
415          * which (according to RFC 1390) should always equal 1 (Ethernet).
416          */
417
418         arp->ar_hrd = htons(np->dev->type);
419         arp->ar_pro = htons(ETH_P_IP);
420         arp->ar_hln = np->dev->addr_len;
421         arp->ar_pln = 4;
422         arp->ar_op = htons(type);
423
424         arp_ptr=(unsigned char *)(arp + 1);
425         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
426         arp_ptr += np->dev->addr_len;
427         memcpy(arp_ptr, &tip, 4);
428         arp_ptr += 4;
429         memcpy(arp_ptr, sha, np->dev->addr_len);
430         arp_ptr += np->dev->addr_len;
431         memcpy(arp_ptr, &sip, 4);
432
433         netpoll_send_skb(np, send_skb);
434 }
435
436 int __netpoll_rx(struct sk_buff *skb)
437 {
438         int proto, len, ulen;
439         struct iphdr *iph;
440         struct udphdr *uh;
441         struct netpoll_info *npi = skb->dev->npinfo;
442         struct netpoll *np = npi->rx_np;
443
444         if (!np)
445                 goto out;
446         if (skb->dev->type != ARPHRD_ETHER)
447                 goto out;
448
449         /* check if netpoll clients need ARP */
450         if (skb->protocol == htons(ETH_P_ARP) &&
451             atomic_read(&trapped)) {
452                 skb_queue_tail(&npi->arp_tx, skb);
453                 return 1;
454         }
455
456         proto = ntohs(eth_hdr(skb)->h_proto);
457         if (proto != ETH_P_IP)
458                 goto out;
459         if (skb->pkt_type == PACKET_OTHERHOST)
460                 goto out;
461         if (skb_shared(skb))
462                 goto out;
463
464         iph = (struct iphdr *)skb->data;
465         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
466                 goto out;
467         if (iph->ihl < 5 || iph->version != 4)
468                 goto out;
469         if (!pskb_may_pull(skb, iph->ihl*4))
470                 goto out;
471         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
472                 goto out;
473
474         len = ntohs(iph->tot_len);
475         if (skb->len < len || len < iph->ihl*4)
476                 goto out;
477
478         /*
479          * Our transport medium may have padded the buffer out.
480          * Now We trim to the true length of the frame.
481          */
482         if (pskb_trim_rcsum(skb, len))
483                 goto out;
484
485         if (iph->protocol != IPPROTO_UDP)
486                 goto out;
487
488         len -= iph->ihl*4;
489         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
490         ulen = ntohs(uh->len);
491
492         if (ulen != len)
493                 goto out;
494         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
495                 goto out;
496         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
497                 goto out;
498         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
499                 goto out;
500         if (np->local_port && np->local_port != ntohs(uh->dest))
501                 goto out;
502
503         np->rx_hook(np, ntohs(uh->source),
504                     (char *)(uh+1),
505                     ulen - sizeof(struct udphdr));
506
507         kfree_skb(skb);
508         return 1;
509
510 out:
511         if (atomic_read(&trapped)) {
512                 kfree_skb(skb);
513                 return 1;
514         }
515
516         return 0;
517 }
518
519 int netpoll_parse_options(struct netpoll *np, char *opt)
520 {
521         char *cur=opt, *delim;
522
523         if (*cur != '@') {
524                 if ((delim = strchr(cur, '@')) == NULL)
525                         goto parse_failed;
526                 *delim = 0;
527                 np->local_port = simple_strtol(cur, NULL, 10);
528                 cur = delim;
529         }
530         cur++;
531         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
532
533         if (*cur != '/') {
534                 if ((delim = strchr(cur, '/')) == NULL)
535                         goto parse_failed;
536                 *delim = 0;
537                 np->local_ip = ntohl(in_aton(cur));
538                 cur = delim;
539
540                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
541                        np->name, HIPQUAD(np->local_ip));
542         }
543         cur++;
544
545         if (*cur != ',') {
546                 /* parse out dev name */
547                 if ((delim = strchr(cur, ',')) == NULL)
548                         goto parse_failed;
549                 *delim = 0;
550                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
551                 cur = delim;
552         }
553         cur++;
554
555         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
556
557         if (*cur != '@') {
558                 /* dst port */
559                 if ((delim = strchr(cur, '@')) == NULL)
560                         goto parse_failed;
561                 *delim = 0;
562                 np->remote_port = simple_strtol(cur, NULL, 10);
563                 cur = delim;
564         }
565         cur++;
566         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
567
568         /* dst ip */
569         if ((delim = strchr(cur, '/')) == NULL)
570                 goto parse_failed;
571         *delim = 0;
572         np->remote_ip = ntohl(in_aton(cur));
573         cur = delim + 1;
574
575         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
576                np->name, HIPQUAD(np->remote_ip));
577
578         if (*cur != 0) {
579                 /* MAC address */
580                 if ((delim = strchr(cur, ':')) == NULL)
581                         goto parse_failed;
582                 *delim = 0;
583                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
584                 cur = delim + 1;
585                 if ((delim = strchr(cur, ':')) == NULL)
586                         goto parse_failed;
587                 *delim = 0;
588                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
589                 cur = delim + 1;
590                 if ((delim = strchr(cur, ':')) == NULL)
591                         goto parse_failed;
592                 *delim = 0;
593                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
594                 cur = delim + 1;
595                 if ((delim = strchr(cur, ':')) == NULL)
596                         goto parse_failed;
597                 *delim = 0;
598                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
599                 cur = delim + 1;
600                 if ((delim = strchr(cur, ':')) == NULL)
601                         goto parse_failed;
602                 *delim = 0;
603                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
604                 cur = delim + 1;
605                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
606         }
607
608         printk(KERN_INFO "%s: remote ethernet address "
609                "%02x:%02x:%02x:%02x:%02x:%02x\n",
610                np->name,
611                np->remote_mac[0],
612                np->remote_mac[1],
613                np->remote_mac[2],
614                np->remote_mac[3],
615                np->remote_mac[4],
616                np->remote_mac[5]);
617
618         return 0;
619
620  parse_failed:
621         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
622                np->name, cur);
623         return -1;
624 }
625
626 int netpoll_setup(struct netpoll *np)
627 {
628         struct net_device *ndev = NULL;
629         struct in_device *in_dev;
630         struct netpoll_info *npinfo;
631         unsigned long flags;
632         int err;
633
634         if (np->dev_name)
635                 ndev = dev_get_by_name(np->dev_name);
636         if (!ndev) {
637                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
638                        np->name, np->dev_name);
639                 return -ENODEV;
640         }
641
642         np->dev = ndev;
643         if (!ndev->npinfo) {
644                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
645                 if (!npinfo) {
646                         err = -ENOMEM;
647                         goto release;
648                 }
649
650                 npinfo->rx_flags = 0;
651                 npinfo->rx_np = NULL;
652                 spin_lock_init(&npinfo->poll_lock);
653                 npinfo->poll_owner = -1;
654
655                 spin_lock_init(&npinfo->rx_lock);
656                 skb_queue_head_init(&npinfo->arp_tx);
657                 skb_queue_head_init(&npinfo->txq);
658                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
659
660                 atomic_set(&npinfo->refcnt, 1);
661         } else {
662                 npinfo = ndev->npinfo;
663                 atomic_inc(&npinfo->refcnt);
664         }
665
666         if (!ndev->poll_controller) {
667                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
668                        np->name, np->dev_name);
669                 err = -ENOTSUPP;
670                 goto release;
671         }
672
673         if (!netif_running(ndev)) {
674                 unsigned long atmost, atleast;
675
676                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
677                        np->name, np->dev_name);
678
679                 rtnl_lock();
680                 err = dev_open(ndev);
681                 rtnl_unlock();
682
683                 if (err) {
684                         printk(KERN_ERR "%s: failed to open %s\n",
685                                np->name, ndev->name);
686                         goto release;
687                 }
688
689                 atleast = jiffies + HZ/10;
690                 atmost = jiffies + 4*HZ;
691                 while (!netif_carrier_ok(ndev)) {
692                         if (time_after(jiffies, atmost)) {
693                                 printk(KERN_NOTICE
694                                        "%s: timeout waiting for carrier\n",
695                                        np->name);
696                                 break;
697                         }
698                         cond_resched();
699                 }
700
701                 /* If carrier appears to come up instantly, we don't
702                  * trust it and pause so that we don't pump all our
703                  * queued console messages into the bitbucket.
704                  */
705
706                 if (time_before(jiffies, atleast)) {
707                         printk(KERN_NOTICE "%s: carrier detect appears"
708                                " untrustworthy, waiting 4 seconds\n",
709                                np->name);
710                         msleep(4000);
711                 }
712         }
713
714         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
715                 memcpy(np->local_mac, ndev->dev_addr, 6);
716
717         if (!np->local_ip) {
718                 rcu_read_lock();
719                 in_dev = __in_dev_get_rcu(ndev);
720
721                 if (!in_dev || !in_dev->ifa_list) {
722                         rcu_read_unlock();
723                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
724                                np->name, np->dev_name);
725                         err = -EDESTADDRREQ;
726                         goto release;
727                 }
728
729                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
730                 rcu_read_unlock();
731                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
732                        np->name, HIPQUAD(np->local_ip));
733         }
734
735         if (np->rx_hook) {
736                 spin_lock_irqsave(&npinfo->rx_lock, flags);
737                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
738                 npinfo->rx_np = np;
739                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
740         }
741
742         /* fill up the skb queue */
743         refill_skbs();
744
745         /* last thing to do is link it to the net device structure */
746         ndev->npinfo = npinfo;
747
748         /* avoid racing with NAPI reading npinfo */
749         synchronize_rcu();
750
751         return 0;
752
753  release:
754         if (!ndev->npinfo)
755                 kfree(npinfo);
756         np->dev = NULL;
757         dev_put(ndev);
758         return err;
759 }
760
761 static int __init netpoll_init(void)
762 {
763         skb_queue_head_init(&skb_pool);
764         return 0;
765 }
766 core_initcall(netpoll_init);
767
768 void netpoll_cleanup(struct netpoll *np)
769 {
770         struct netpoll_info *npinfo;
771         unsigned long flags;
772
773         if (np->dev) {
774                 npinfo = np->dev->npinfo;
775                 if (npinfo) {
776                         if (npinfo->rx_np == np) {
777                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
778                                 npinfo->rx_np = NULL;
779                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
780                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
781                         }
782
783                         np->dev->npinfo = NULL;
784                         if (atomic_dec_and_test(&npinfo->refcnt)) {
785                                 skb_queue_purge(&npinfo->arp_tx);
786                                 skb_queue_purge(&npinfo->txq);
787                                 cancel_rearming_delayed_work(&npinfo->tx_work);
788                                 flush_scheduled_work();
789
790                                 kfree(npinfo);
791                         }
792                 }
793
794                 dev_put(np->dev);
795         }
796
797         np->dev = NULL;
798 }
799
800 int netpoll_trap(void)
801 {
802         return atomic_read(&trapped);
803 }
804
805 void netpoll_set_trap(int trap)
806 {
807         if (trap)
808                 atomic_inc(&trapped);
809         else
810                 atomic_dec(&trapped);
811 }
812
813 EXPORT_SYMBOL(netpoll_set_trap);
814 EXPORT_SYMBOL(netpoll_trap);
815 EXPORT_SYMBOL(netpoll_parse_options);
816 EXPORT_SYMBOL(netpoll_setup);
817 EXPORT_SYMBOL(netpoll_cleanup);
818 EXPORT_SYMBOL(netpoll_send_udp);
819 EXPORT_SYMBOL(netpoll_poll);