496b06244a8e9bad36a032355b7bdb7ab2557472
[linux-2.6.git] / 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/smp_lock.h>
13 #include <linux/netdevice.h>
14 #include <linux/etherdevice.h>
15 #include <linux/string.h>
16 #include <linux/if_arp.h>
17 #include <linux/inetdevice.h>
18 #include <linux/inet.h>
19 #include <linux/interrupt.h>
20 #include <linux/netpoll.h>
21 #include <linux/sched.h>
22 #include <linux/delay.h>
23 #include <linux/rcupdate.h>
24 #include <linux/workqueue.h>
25 #include <net/tcp.h>
26 #include <net/udp.h>
27 #include <asm/unaligned.h>
28
29 /*
30  * We maintain a small pool of fully-sized skbs, to make sure the
31  * message gets out even in extreme OOM situations.
32  */
33
34 #define MAX_UDP_CHUNK 1460
35 #define MAX_SKBS 32
36 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
37
38 static struct sk_buff_head skb_pool;
39
40 static atomic_t trapped;
41
42 #define USEC_PER_POLL   50
43 #define NETPOLL_RX_ENABLED  1
44 #define NETPOLL_RX_DROP     2
45
46 #define MAX_SKB_SIZE \
47                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
48                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
49
50 static void zap_completion_queue(void);
51 static void arp_reply(struct sk_buff *skb);
52
53 static void queue_process(struct work_struct *work)
54 {
55         struct netpoll_info *npinfo =
56                 container_of(work, struct netpoll_info, tx_work.work);
57         struct sk_buff *skb;
58         unsigned long flags;
59
60         while ((skb = skb_dequeue(&npinfo->txq))) {
61                 struct net_device *dev = skb->dev;
62
63                 if (!netif_device_present(dev) || !netif_running(dev)) {
64                         __kfree_skb(skb);
65                         continue;
66                 }
67
68                 local_irq_save(flags);
69                 netif_tx_lock(dev);
70                 if (netif_queue_stopped(dev) ||
71                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
72                         skb_queue_head(&npinfo->txq, skb);
73                         netif_tx_unlock(dev);
74                         local_irq_restore(flags);
75
76                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
77                         return;
78                 }
79                 netif_tx_unlock(dev);
80                 local_irq_restore(flags);
81         }
82 }
83
84 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
85                             unsigned short ulen, __be32 saddr, __be32 daddr)
86 {
87         __wsum psum;
88
89         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
90                 return 0;
91
92         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
93
94         if (skb->ip_summed == CHECKSUM_COMPLETE &&
95             !csum_fold(csum_add(psum, skb->csum)))
96                 return 0;
97
98         skb->csum = psum;
99
100         return __skb_checksum_complete(skb);
101 }
102
103 /*
104  * Check whether delayed processing was scheduled for our NIC. If so,
105  * we attempt to grab the poll lock and use ->poll() to pump the card.
106  * If this fails, either we've recursed in ->poll() or it's already
107  * running on another CPU.
108  *
109  * Note: we don't mask interrupts with this lock because we're using
110  * trylock here and interrupts are already disabled in the softirq
111  * case. Further, we test the poll_owner to avoid recursion on UP
112  * systems where the lock doesn't exist.
113  *
114  * In cases where there is bi-directional communications, reading only
115  * one message at a time can lead to packets being dropped by the
116  * network adapter, forcing superfluous retries and possibly timeouts.
117  * Thus, we set our budget to greater than 1.
118  */
119 static void poll_napi(struct netpoll *np)
120 {
121         struct netpoll_info *npinfo = np->dev->npinfo;
122         int budget = 16;
123
124         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
125             npinfo->poll_owner != smp_processor_id() &&
126             spin_trylock(&npinfo->poll_lock)) {
127                 npinfo->rx_flags |= NETPOLL_RX_DROP;
128                 atomic_inc(&trapped);
129
130                 np->dev->poll(np->dev, &budget);
131
132                 atomic_dec(&trapped);
133                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
134                 spin_unlock(&npinfo->poll_lock);
135         }
136 }
137
138 static void service_arp_queue(struct netpoll_info *npi)
139 {
140         struct sk_buff *skb;
141
142         if (unlikely(!npi))
143                 return;
144
145         skb = skb_dequeue(&npi->arp_tx);
146
147         while (skb != NULL) {
148                 arp_reply(skb);
149                 skb = skb_dequeue(&npi->arp_tx);
150         }
151 }
152
153 void netpoll_poll(struct netpoll *np)
154 {
155         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
156                 return;
157
158         /* Process pending work on NIC */
159         np->dev->poll_controller(np->dev);
160         if (np->dev->poll)
161                 poll_napi(np);
162
163         service_arp_queue(np->dev->npinfo);
164
165         zap_completion_queue();
166 }
167
168 static void refill_skbs(void)
169 {
170         struct sk_buff *skb;
171         unsigned long flags;
172
173         spin_lock_irqsave(&skb_pool.lock, flags);
174         while (skb_pool.qlen < MAX_SKBS) {
175                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
176                 if (!skb)
177                         break;
178
179                 __skb_queue_tail(&skb_pool, skb);
180         }
181         spin_unlock_irqrestore(&skb_pool.lock, flags);
182 }
183
184 static void zap_completion_queue(void)
185 {
186         unsigned long flags;
187         struct softnet_data *sd = &get_cpu_var(softnet_data);
188
189         if (sd->completion_queue) {
190                 struct sk_buff *clist;
191
192                 local_irq_save(flags);
193                 clist = sd->completion_queue;
194                 sd->completion_queue = NULL;
195                 local_irq_restore(flags);
196
197                 while (clist != NULL) {
198                         struct sk_buff *skb = clist;
199                         clist = clist->next;
200                         if (skb->destructor)
201                                 dev_kfree_skb_any(skb); /* put this one back */
202                         else
203                                 __kfree_skb(skb);
204                 }
205         }
206
207         put_cpu_var(softnet_data);
208 }
209
210 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
211 {
212         int count = 0;
213         struct sk_buff *skb;
214
215         zap_completion_queue();
216         refill_skbs();
217 repeat:
218
219         skb = alloc_skb(len, GFP_ATOMIC);
220         if (!skb)
221                 skb = skb_dequeue(&skb_pool);
222
223         if (!skb) {
224                 if (++count < 10) {
225                         netpoll_poll(np);
226                         goto repeat;
227                 }
228                 return NULL;
229         }
230
231         atomic_set(&skb->users, 1);
232         skb_reserve(skb, reserve);
233         return skb;
234 }
235
236 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
237 {
238         int status = NETDEV_TX_BUSY;
239         unsigned long tries;
240         struct net_device *dev = np->dev;
241         struct netpoll_info *npinfo = np->dev->npinfo;
242
243         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
244                 __kfree_skb(skb);
245                 return;
246         }
247
248         /* don't get messages out of order, and no recursion */
249         if (skb_queue_len(&npinfo->txq) == 0 &&
250                     npinfo->poll_owner != smp_processor_id()) {
251                 unsigned long flags;
252
253                 local_irq_save(flags);
254                 if (netif_tx_trylock(dev)) {
255                         /* try until next clock tick */
256                         for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
257                                         tries > 0; --tries) {
258                                 if (!netif_queue_stopped(dev))
259                                         status = dev->hard_start_xmit(skb, dev);
260
261                                 if (status == NETDEV_TX_OK)
262                                         break;
263
264                                 /* tickle device maybe there is some cleanup */
265                                 netpoll_poll(np);
266
267                                 udelay(USEC_PER_POLL);
268                         }
269                         netif_tx_unlock(dev);
270                 }
271                 local_irq_restore(flags);
272         }
273
274         if (status != NETDEV_TX_OK) {
275                 skb_queue_tail(&npinfo->txq, skb);
276                 schedule_delayed_work(&npinfo->tx_work,0);
277         }
278 }
279
280 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
281 {
282         int total_len, eth_len, ip_len, udp_len;
283         struct sk_buff *skb;
284         struct udphdr *udph;
285         struct iphdr *iph;
286         struct ethhdr *eth;
287
288         udp_len = len + sizeof(*udph);
289         ip_len = eth_len = udp_len + sizeof(*iph);
290         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
291
292         skb = find_skb(np, total_len, total_len - len);
293         if (!skb)
294                 return;
295
296         memcpy(skb->data, msg, len);
297         skb->len += len;
298
299         skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
300         udph->source = htons(np->local_port);
301         udph->dest = htons(np->remote_port);
302         udph->len = htons(udp_len);
303         udph->check = 0;
304         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
305                                         htonl(np->remote_ip),
306                                         udp_len, IPPROTO_UDP,
307                                         csum_partial((unsigned char *)udph, udp_len, 0));
308         if (udph->check == 0)
309                 udph->check = CSUM_MANGLED_0;
310
311         skb_push(skb, sizeof(*iph));
312         skb_reset_network_header(skb);
313         iph = ip_hdr(skb);
314
315         /* iph->version = 4; iph->ihl = 5; */
316         put_unaligned(0x45, (unsigned char *)iph);
317         iph->tos      = 0;
318         put_unaligned(htons(ip_len), &(iph->tot_len));
319         iph->id       = 0;
320         iph->frag_off = 0;
321         iph->ttl      = 64;
322         iph->protocol = IPPROTO_UDP;
323         iph->check    = 0;
324         put_unaligned(htonl(np->local_ip), &(iph->saddr));
325         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
326         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
327
328         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
329         skb_reset_mac_header(skb);
330         skb->protocol = eth->h_proto = htons(ETH_P_IP);
331         memcpy(eth->h_source, np->local_mac, 6);
332         memcpy(eth->h_dest, np->remote_mac, 6);
333
334         skb->dev = np->dev;
335
336         netpoll_send_skb(np, skb);
337 }
338
339 static void arp_reply(struct sk_buff *skb)
340 {
341         struct netpoll_info *npinfo = skb->dev->npinfo;
342         struct arphdr *arp;
343         unsigned char *arp_ptr;
344         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
345         __be32 sip, tip;
346         unsigned char *sha;
347         struct sk_buff *send_skb;
348         struct netpoll *np = NULL;
349
350         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
351                 np = npinfo->rx_np;
352         if (!np)
353                 return;
354
355         /* No arp on this interface */
356         if (skb->dev->flags & IFF_NOARP)
357                 return;
358
359         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
360                                  (2 * skb->dev->addr_len) +
361                                  (2 * sizeof(u32)))))
362                 return;
363
364         skb_reset_network_header(skb);
365         skb->h.raw = skb->data;
366         arp = arp_hdr(skb);
367
368         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
369              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
370             arp->ar_pro != htons(ETH_P_IP) ||
371             arp->ar_op != htons(ARPOP_REQUEST))
372                 return;
373
374         arp_ptr = (unsigned char *)(arp+1);
375         /* save the location of the src hw addr */
376         sha = arp_ptr;
377         arp_ptr += skb->dev->addr_len;
378         memcpy(&sip, arp_ptr, 4);
379         arp_ptr += 4;
380         /* if we actually cared about dst hw addr, it would get copied here */
381         arp_ptr += skb->dev->addr_len;
382         memcpy(&tip, arp_ptr, 4);
383
384         /* Should we ignore arp? */
385         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
386                 return;
387
388         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
389         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
390                             LL_RESERVED_SPACE(np->dev));
391
392         if (!send_skb)
393                 return;
394
395         skb_reset_network_header(send_skb);
396         arp = (struct arphdr *) skb_put(send_skb, size);
397         send_skb->dev = skb->dev;
398         send_skb->protocol = htons(ETH_P_ARP);
399
400         /* Fill the device header for the ARP frame */
401
402         if (np->dev->hard_header &&
403             np->dev->hard_header(send_skb, skb->dev, ptype,
404                                  sha, np->local_mac,
405                                  send_skb->len) < 0) {
406                 kfree_skb(send_skb);
407                 return;
408         }
409
410         /*
411          * Fill out the arp protocol part.
412          *
413          * we only support ethernet device type,
414          * which (according to RFC 1390) should always equal 1 (Ethernet).
415          */
416
417         arp->ar_hrd = htons(np->dev->type);
418         arp->ar_pro = htons(ETH_P_IP);
419         arp->ar_hln = np->dev->addr_len;
420         arp->ar_pln = 4;
421         arp->ar_op = htons(type);
422
423         arp_ptr=(unsigned char *)(arp + 1);
424         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
425         arp_ptr += np->dev->addr_len;
426         memcpy(arp_ptr, &tip, 4);
427         arp_ptr += 4;
428         memcpy(arp_ptr, sha, np->dev->addr_len);
429         arp_ptr += np->dev->addr_len;
430         memcpy(arp_ptr, &sip, 4);
431
432         netpoll_send_skb(np, send_skb);
433 }
434
435 int __netpoll_rx(struct sk_buff *skb)
436 {
437         int proto, len, ulen;
438         struct iphdr *iph;
439         struct udphdr *uh;
440         struct netpoll_info *npi = skb->dev->npinfo;
441         struct netpoll *np = npi->rx_np;
442
443         if (!np)
444                 goto out;
445         if (skb->dev->type != ARPHRD_ETHER)
446                 goto out;
447
448         /* check if netpoll clients need ARP */
449         if (skb->protocol == htons(ETH_P_ARP) &&
450             atomic_read(&trapped)) {
451                 skb_queue_tail(&npi->arp_tx, skb);
452                 return 1;
453         }
454
455         proto = ntohs(eth_hdr(skb)->h_proto);
456         if (proto != ETH_P_IP)
457                 goto out;
458         if (skb->pkt_type == PACKET_OTHERHOST)
459                 goto out;
460         if (skb_shared(skb))
461                 goto out;
462
463         iph = (struct iphdr *)skb->data;
464         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
465                 goto out;
466         if (iph->ihl < 5 || iph->version != 4)
467                 goto out;
468         if (!pskb_may_pull(skb, iph->ihl*4))
469                 goto out;
470         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
471                 goto out;
472
473         len = ntohs(iph->tot_len);
474         if (skb->len < len || len < iph->ihl*4)
475                 goto out;
476
477         /*
478          * Our transport medium may have padded the buffer out.
479          * Now We trim to the true length of the frame.
480          */
481         if (pskb_trim_rcsum(skb, len))
482                 goto out;
483
484         if (iph->protocol != IPPROTO_UDP)
485                 goto out;
486
487         len -= iph->ihl*4;
488         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
489         ulen = ntohs(uh->len);
490
491         if (ulen != len)
492                 goto out;
493         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
494                 goto out;
495         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
496                 goto out;
497         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
498                 goto out;
499         if (np->local_port && np->local_port != ntohs(uh->dest))
500                 goto out;
501
502         np->rx_hook(np, ntohs(uh->source),
503                     (char *)(uh+1),
504                     ulen - sizeof(struct udphdr));
505
506         kfree_skb(skb);
507         return 1;
508
509 out:
510         if (atomic_read(&trapped)) {
511                 kfree_skb(skb);
512                 return 1;
513         }
514
515         return 0;
516 }
517
518 int netpoll_parse_options(struct netpoll *np, char *opt)
519 {
520         char *cur=opt, *delim;
521
522         if (*cur != '@') {
523                 if ((delim = strchr(cur, '@')) == NULL)
524                         goto parse_failed;
525                 *delim = 0;
526                 np->local_port = simple_strtol(cur, NULL, 10);
527                 cur = delim;
528         }
529         cur++;
530         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
531
532         if (*cur != '/') {
533                 if ((delim = strchr(cur, '/')) == NULL)
534                         goto parse_failed;
535                 *delim = 0;
536                 np->local_ip = ntohl(in_aton(cur));
537                 cur = delim;
538
539                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
540                        np->name, HIPQUAD(np->local_ip));
541         }
542         cur++;
543
544         if (*cur != ',') {
545                 /* parse out dev name */
546                 if ((delim = strchr(cur, ',')) == NULL)
547                         goto parse_failed;
548                 *delim = 0;
549                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
550                 cur = delim;
551         }
552         cur++;
553
554         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
555
556         if (*cur != '@') {
557                 /* dst port */
558                 if ((delim = strchr(cur, '@')) == NULL)
559                         goto parse_failed;
560                 *delim = 0;
561                 np->remote_port = simple_strtol(cur, NULL, 10);
562                 cur = delim;
563         }
564         cur++;
565         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
566
567         /* dst ip */
568         if ((delim = strchr(cur, '/')) == NULL)
569                 goto parse_failed;
570         *delim = 0;
571         np->remote_ip = ntohl(in_aton(cur));
572         cur = delim + 1;
573
574         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
575                np->name, HIPQUAD(np->remote_ip));
576
577         if (*cur != 0) {
578                 /* MAC address */
579                 if ((delim = strchr(cur, ':')) == NULL)
580                         goto parse_failed;
581                 *delim = 0;
582                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
583                 cur = delim + 1;
584                 if ((delim = strchr(cur, ':')) == NULL)
585                         goto parse_failed;
586                 *delim = 0;
587                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
588                 cur = delim + 1;
589                 if ((delim = strchr(cur, ':')) == NULL)
590                         goto parse_failed;
591                 *delim = 0;
592                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
593                 cur = delim + 1;
594                 if ((delim = strchr(cur, ':')) == NULL)
595                         goto parse_failed;
596                 *delim = 0;
597                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
598                 cur = delim + 1;
599                 if ((delim = strchr(cur, ':')) == NULL)
600                         goto parse_failed;
601                 *delim = 0;
602                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
603                 cur = delim + 1;
604                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
605         }
606
607         printk(KERN_INFO "%s: remote ethernet address "
608                "%02x:%02x:%02x:%02x:%02x:%02x\n",
609                np->name,
610                np->remote_mac[0],
611                np->remote_mac[1],
612                np->remote_mac[2],
613                np->remote_mac[3],
614                np->remote_mac[4],
615                np->remote_mac[5]);
616
617         return 0;
618
619  parse_failed:
620         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
621                np->name, cur);
622         return -1;
623 }
624
625 int netpoll_setup(struct netpoll *np)
626 {
627         struct net_device *ndev = NULL;
628         struct in_device *in_dev;
629         struct netpoll_info *npinfo;
630         unsigned long flags;
631         int err;
632
633         if (np->dev_name)
634                 ndev = dev_get_by_name(np->dev_name);
635         if (!ndev) {
636                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
637                        np->name, np->dev_name);
638                 return -ENODEV;
639         }
640
641         np->dev = ndev;
642         if (!ndev->npinfo) {
643                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
644                 if (!npinfo) {
645                         err = -ENOMEM;
646                         goto release;
647                 }
648
649                 npinfo->rx_flags = 0;
650                 npinfo->rx_np = NULL;
651                 spin_lock_init(&npinfo->poll_lock);
652                 npinfo->poll_owner = -1;
653
654                 spin_lock_init(&npinfo->rx_lock);
655                 skb_queue_head_init(&npinfo->arp_tx);
656                 skb_queue_head_init(&npinfo->txq);
657                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
658
659                 atomic_set(&npinfo->refcnt, 1);
660         } else {
661                 npinfo = ndev->npinfo;
662                 atomic_inc(&npinfo->refcnt);
663         }
664
665         if (!ndev->poll_controller) {
666                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
667                        np->name, np->dev_name);
668                 err = -ENOTSUPP;
669                 goto release;
670         }
671
672         if (!netif_running(ndev)) {
673                 unsigned long atmost, atleast;
674
675                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
676                        np->name, np->dev_name);
677
678                 rtnl_lock();
679                 err = dev_open(ndev);
680                 rtnl_unlock();
681
682                 if (err) {
683                         printk(KERN_ERR "%s: failed to open %s\n",
684                                np->name, ndev->name);
685                         goto release;
686                 }
687
688                 atleast = jiffies + HZ/10;
689                 atmost = jiffies + 4*HZ;
690                 while (!netif_carrier_ok(ndev)) {
691                         if (time_after(jiffies, atmost)) {
692                                 printk(KERN_NOTICE
693                                        "%s: timeout waiting for carrier\n",
694                                        np->name);
695                                 break;
696                         }
697                         cond_resched();
698                 }
699
700                 /* If carrier appears to come up instantly, we don't
701                  * trust it and pause so that we don't pump all our
702                  * queued console messages into the bitbucket.
703                  */
704
705                 if (time_before(jiffies, atleast)) {
706                         printk(KERN_NOTICE "%s: carrier detect appears"
707                                " untrustworthy, waiting 4 seconds\n",
708                                np->name);
709                         msleep(4000);
710                 }
711         }
712
713         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
714                 memcpy(np->local_mac, ndev->dev_addr, 6);
715
716         if (!np->local_ip) {
717                 rcu_read_lock();
718                 in_dev = __in_dev_get_rcu(ndev);
719
720                 if (!in_dev || !in_dev->ifa_list) {
721                         rcu_read_unlock();
722                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
723                                np->name, np->dev_name);
724                         err = -EDESTADDRREQ;
725                         goto release;
726                 }
727
728                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
729                 rcu_read_unlock();
730                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
731                        np->name, HIPQUAD(np->local_ip));
732         }
733
734         if (np->rx_hook) {
735                 spin_lock_irqsave(&npinfo->rx_lock, flags);
736                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
737                 npinfo->rx_np = np;
738                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
739         }
740
741         /* fill up the skb queue */
742         refill_skbs();
743
744         /* last thing to do is link it to the net device structure */
745         ndev->npinfo = npinfo;
746
747         /* avoid racing with NAPI reading npinfo */
748         synchronize_rcu();
749
750         return 0;
751
752  release:
753         if (!ndev->npinfo)
754                 kfree(npinfo);
755         np->dev = NULL;
756         dev_put(ndev);
757         return err;
758 }
759
760 static int __init netpoll_init(void)
761 {
762         skb_queue_head_init(&skb_pool);
763         return 0;
764 }
765 core_initcall(netpoll_init);
766
767 void netpoll_cleanup(struct netpoll *np)
768 {
769         struct netpoll_info *npinfo;
770         unsigned long flags;
771
772         if (np->dev) {
773                 npinfo = np->dev->npinfo;
774                 if (npinfo) {
775                         if (npinfo->rx_np == np) {
776                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
777                                 npinfo->rx_np = NULL;
778                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
779                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
780                         }
781
782                         np->dev->npinfo = NULL;
783                         if (atomic_dec_and_test(&npinfo->refcnt)) {
784                                 skb_queue_purge(&npinfo->arp_tx);
785                                 skb_queue_purge(&npinfo->txq);
786                                 cancel_rearming_delayed_work(&npinfo->tx_work);
787                                 flush_scheduled_work();
788
789                                 kfree(npinfo);
790                         }
791                 }
792
793                 dev_put(np->dev);
794         }
795
796         np->dev = NULL;
797 }
798
799 int netpoll_trap(void)
800 {
801         return atomic_read(&trapped);
802 }
803
804 void netpoll_set_trap(int trap)
805 {
806         if (trap)
807                 atomic_inc(&trapped);
808         else
809                 atomic_dec(&trapped);
810 }
811
812 EXPORT_SYMBOL(netpoll_set_trap);
813 EXPORT_SYMBOL(netpoll_trap);
814 EXPORT_SYMBOL(netpoll_parse_options);
815 EXPORT_SYMBOL(netpoll_setup);
816 EXPORT_SYMBOL(netpoll_cleanup);
817 EXPORT_SYMBOL(netpoll_send_udp);
818 EXPORT_SYMBOL(netpoll_poll);