[CORE] Stack changes to add multiqueue hardware support API
[linux-3.10.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/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                      netif_subqueue_stopped(dev, skb->queue_mapping)) ||
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_csum_unnecessary(skb))
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                 /* try until next clock tick */
255                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
256                      tries > 0; --tries) {
257                         if (netif_tx_trylock(dev)) {
258                                 if (!netif_queue_stopped(dev) &&
259                                     !netif_subqueue_stopped(dev, skb->queue_mapping))
260                                         status = dev->hard_start_xmit(skb, dev);
261                                 netif_tx_unlock(dev);
262
263                                 if (status == NETDEV_TX_OK)
264                                         break;
265
266                         }
267
268                         /* tickle device maybe there is some cleanup */
269                         netpoll_poll(np);
270
271                         udelay(USEC_PER_POLL);
272                 }
273                 local_irq_restore(flags);
274         }
275
276         if (status != NETDEV_TX_OK) {
277                 skb_queue_tail(&npinfo->txq, skb);
278                 schedule_delayed_work(&npinfo->tx_work,0);
279         }
280 }
281
282 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
283 {
284         int total_len, eth_len, ip_len, udp_len;
285         struct sk_buff *skb;
286         struct udphdr *udph;
287         struct iphdr *iph;
288         struct ethhdr *eth;
289
290         udp_len = len + sizeof(*udph);
291         ip_len = eth_len = udp_len + sizeof(*iph);
292         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
293
294         skb = find_skb(np, total_len, total_len - len);
295         if (!skb)
296                 return;
297
298         skb_copy_to_linear_data(skb, msg, len);
299         skb->len += len;
300
301         skb_push(skb, sizeof(*udph));
302         skb_reset_transport_header(skb);
303         udph = udp_hdr(skb);
304         udph->source = htons(np->local_port);
305         udph->dest = htons(np->remote_port);
306         udph->len = htons(udp_len);
307         udph->check = 0;
308         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
309                                         htonl(np->remote_ip),
310                                         udp_len, IPPROTO_UDP,
311                                         csum_partial((unsigned char *)udph, udp_len, 0));
312         if (udph->check == 0)
313                 udph->check = CSUM_MANGLED_0;
314
315         skb_push(skb, sizeof(*iph));
316         skb_reset_network_header(skb);
317         iph = ip_hdr(skb);
318
319         /* iph->version = 4; iph->ihl = 5; */
320         put_unaligned(0x45, (unsigned char *)iph);
321         iph->tos      = 0;
322         put_unaligned(htons(ip_len), &(iph->tot_len));
323         iph->id       = 0;
324         iph->frag_off = 0;
325         iph->ttl      = 64;
326         iph->protocol = IPPROTO_UDP;
327         iph->check    = 0;
328         put_unaligned(htonl(np->local_ip), &(iph->saddr));
329         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
330         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
331
332         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
333         skb_reset_mac_header(skb);
334         skb->protocol = eth->h_proto = htons(ETH_P_IP);
335         memcpy(eth->h_source, np->local_mac, 6);
336         memcpy(eth->h_dest, np->remote_mac, 6);
337
338         skb->dev = np->dev;
339
340         netpoll_send_skb(np, skb);
341 }
342
343 static void arp_reply(struct sk_buff *skb)
344 {
345         struct netpoll_info *npinfo = skb->dev->npinfo;
346         struct arphdr *arp;
347         unsigned char *arp_ptr;
348         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
349         __be32 sip, tip;
350         unsigned char *sha;
351         struct sk_buff *send_skb;
352         struct netpoll *np = NULL;
353
354         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
355                 np = npinfo->rx_np;
356         if (!np)
357                 return;
358
359         /* No arp on this interface */
360         if (skb->dev->flags & IFF_NOARP)
361                 return;
362
363         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
364                                  (2 * skb->dev->addr_len) +
365                                  (2 * sizeof(u32)))))
366                 return;
367
368         skb_reset_network_header(skb);
369         skb_reset_transport_header(skb);
370         arp = arp_hdr(skb);
371
372         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
373              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
374             arp->ar_pro != htons(ETH_P_IP) ||
375             arp->ar_op != htons(ARPOP_REQUEST))
376                 return;
377
378         arp_ptr = (unsigned char *)(arp+1);
379         /* save the location of the src hw addr */
380         sha = arp_ptr;
381         arp_ptr += skb->dev->addr_len;
382         memcpy(&sip, arp_ptr, 4);
383         arp_ptr += 4;
384         /* if we actually cared about dst hw addr, it would get copied here */
385         arp_ptr += skb->dev->addr_len;
386         memcpy(&tip, arp_ptr, 4);
387
388         /* Should we ignore arp? */
389         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
390                 return;
391
392         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
393         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
394                             LL_RESERVED_SPACE(np->dev));
395
396         if (!send_skb)
397                 return;
398
399         skb_reset_network_header(send_skb);
400         arp = (struct arphdr *) skb_put(send_skb, size);
401         send_skb->dev = skb->dev;
402         send_skb->protocol = htons(ETH_P_ARP);
403
404         /* Fill the device header for the ARP frame */
405
406         if (np->dev->hard_header &&
407             np->dev->hard_header(send_skb, skb->dev, ptype,
408                                  sha, np->local_mac,
409                                  send_skb->len) < 0) {
410                 kfree_skb(send_skb);
411                 return;
412         }
413
414         /*
415          * Fill out the arp protocol part.
416          *
417          * we only support ethernet device type,
418          * which (according to RFC 1390) should always equal 1 (Ethernet).
419          */
420
421         arp->ar_hrd = htons(np->dev->type);
422         arp->ar_pro = htons(ETH_P_IP);
423         arp->ar_hln = np->dev->addr_len;
424         arp->ar_pln = 4;
425         arp->ar_op = htons(type);
426
427         arp_ptr=(unsigned char *)(arp + 1);
428         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
429         arp_ptr += np->dev->addr_len;
430         memcpy(arp_ptr, &tip, 4);
431         arp_ptr += 4;
432         memcpy(arp_ptr, sha, np->dev->addr_len);
433         arp_ptr += np->dev->addr_len;
434         memcpy(arp_ptr, &sip, 4);
435
436         netpoll_send_skb(np, send_skb);
437 }
438
439 int __netpoll_rx(struct sk_buff *skb)
440 {
441         int proto, len, ulen;
442         struct iphdr *iph;
443         struct udphdr *uh;
444         struct netpoll_info *npi = skb->dev->npinfo;
445         struct netpoll *np = npi->rx_np;
446
447         if (!np)
448                 goto out;
449         if (skb->dev->type != ARPHRD_ETHER)
450                 goto out;
451
452         /* check if netpoll clients need ARP */
453         if (skb->protocol == htons(ETH_P_ARP) &&
454             atomic_read(&trapped)) {
455                 skb_queue_tail(&npi->arp_tx, skb);
456                 return 1;
457         }
458
459         proto = ntohs(eth_hdr(skb)->h_proto);
460         if (proto != ETH_P_IP)
461                 goto out;
462         if (skb->pkt_type == PACKET_OTHERHOST)
463                 goto out;
464         if (skb_shared(skb))
465                 goto out;
466
467         iph = (struct iphdr *)skb->data;
468         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
469                 goto out;
470         if (iph->ihl < 5 || iph->version != 4)
471                 goto out;
472         if (!pskb_may_pull(skb, iph->ihl*4))
473                 goto out;
474         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
475                 goto out;
476
477         len = ntohs(iph->tot_len);
478         if (skb->len < len || len < iph->ihl*4)
479                 goto out;
480
481         /*
482          * Our transport medium may have padded the buffer out.
483          * Now We trim to the true length of the frame.
484          */
485         if (pskb_trim_rcsum(skb, len))
486                 goto out;
487
488         if (iph->protocol != IPPROTO_UDP)
489                 goto out;
490
491         len -= iph->ihl*4;
492         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
493         ulen = ntohs(uh->len);
494
495         if (ulen != len)
496                 goto out;
497         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
498                 goto out;
499         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
500                 goto out;
501         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
502                 goto out;
503         if (np->local_port && np->local_port != ntohs(uh->dest))
504                 goto out;
505
506         np->rx_hook(np, ntohs(uh->source),
507                     (char *)(uh+1),
508                     ulen - sizeof(struct udphdr));
509
510         kfree_skb(skb);
511         return 1;
512
513 out:
514         if (atomic_read(&trapped)) {
515                 kfree_skb(skb);
516                 return 1;
517         }
518
519         return 0;
520 }
521
522 int netpoll_parse_options(struct netpoll *np, char *opt)
523 {
524         char *cur=opt, *delim;
525
526         if (*cur != '@') {
527                 if ((delim = strchr(cur, '@')) == NULL)
528                         goto parse_failed;
529                 *delim = 0;
530                 np->local_port = simple_strtol(cur, NULL, 10);
531                 cur = delim;
532         }
533         cur++;
534         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
535
536         if (*cur != '/') {
537                 if ((delim = strchr(cur, '/')) == NULL)
538                         goto parse_failed;
539                 *delim = 0;
540                 np->local_ip = ntohl(in_aton(cur));
541                 cur = delim;
542
543                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
544                        np->name, HIPQUAD(np->local_ip));
545         }
546         cur++;
547
548         if (*cur != ',') {
549                 /* parse out dev name */
550                 if ((delim = strchr(cur, ',')) == NULL)
551                         goto parse_failed;
552                 *delim = 0;
553                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
554                 cur = delim;
555         }
556         cur++;
557
558         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
559
560         if (*cur != '@') {
561                 /* dst port */
562                 if ((delim = strchr(cur, '@')) == NULL)
563                         goto parse_failed;
564                 *delim = 0;
565                 np->remote_port = simple_strtol(cur, NULL, 10);
566                 cur = delim;
567         }
568         cur++;
569         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
570
571         /* dst ip */
572         if ((delim = strchr(cur, '/')) == NULL)
573                 goto parse_failed;
574         *delim = 0;
575         np->remote_ip = ntohl(in_aton(cur));
576         cur = delim + 1;
577
578         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
579                np->name, HIPQUAD(np->remote_ip));
580
581         if (*cur != 0) {
582                 /* MAC address */
583                 if ((delim = strchr(cur, ':')) == NULL)
584                         goto parse_failed;
585                 *delim = 0;
586                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
587                 cur = delim + 1;
588                 if ((delim = strchr(cur, ':')) == NULL)
589                         goto parse_failed;
590                 *delim = 0;
591                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
592                 cur = delim + 1;
593                 if ((delim = strchr(cur, ':')) == NULL)
594                         goto parse_failed;
595                 *delim = 0;
596                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
597                 cur = delim + 1;
598                 if ((delim = strchr(cur, ':')) == NULL)
599                         goto parse_failed;
600                 *delim = 0;
601                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
602                 cur = delim + 1;
603                 if ((delim = strchr(cur, ':')) == NULL)
604                         goto parse_failed;
605                 *delim = 0;
606                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
607                 cur = delim + 1;
608                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
609         }
610
611         printk(KERN_INFO "%s: remote ethernet address "
612                "%02x:%02x:%02x:%02x:%02x:%02x\n",
613                np->name,
614                np->remote_mac[0],
615                np->remote_mac[1],
616                np->remote_mac[2],
617                np->remote_mac[3],
618                np->remote_mac[4],
619                np->remote_mac[5]);
620
621         return 0;
622
623  parse_failed:
624         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
625                np->name, cur);
626         return -1;
627 }
628
629 int netpoll_setup(struct netpoll *np)
630 {
631         struct net_device *ndev = NULL;
632         struct in_device *in_dev;
633         struct netpoll_info *npinfo;
634         unsigned long flags;
635         int err;
636
637         if (np->dev_name)
638                 ndev = dev_get_by_name(np->dev_name);
639         if (!ndev) {
640                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
641                        np->name, np->dev_name);
642                 return -ENODEV;
643         }
644
645         np->dev = ndev;
646         if (!ndev->npinfo) {
647                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
648                 if (!npinfo) {
649                         err = -ENOMEM;
650                         goto release;
651                 }
652
653                 npinfo->rx_flags = 0;
654                 npinfo->rx_np = NULL;
655                 spin_lock_init(&npinfo->poll_lock);
656                 npinfo->poll_owner = -1;
657
658                 spin_lock_init(&npinfo->rx_lock);
659                 skb_queue_head_init(&npinfo->arp_tx);
660                 skb_queue_head_init(&npinfo->txq);
661                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
662
663                 atomic_set(&npinfo->refcnt, 1);
664         } else {
665                 npinfo = ndev->npinfo;
666                 atomic_inc(&npinfo->refcnt);
667         }
668
669         if (!ndev->poll_controller) {
670                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
671                        np->name, np->dev_name);
672                 err = -ENOTSUPP;
673                 goto release;
674         }
675
676         if (!netif_running(ndev)) {
677                 unsigned long atmost, atleast;
678
679                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
680                        np->name, np->dev_name);
681
682                 rtnl_lock();
683                 err = dev_open(ndev);
684                 rtnl_unlock();
685
686                 if (err) {
687                         printk(KERN_ERR "%s: failed to open %s\n",
688                                np->name, ndev->name);
689                         goto release;
690                 }
691
692                 atleast = jiffies + HZ/10;
693                 atmost = jiffies + 4*HZ;
694                 while (!netif_carrier_ok(ndev)) {
695                         if (time_after(jiffies, atmost)) {
696                                 printk(KERN_NOTICE
697                                        "%s: timeout waiting for carrier\n",
698                                        np->name);
699                                 break;
700                         }
701                         cond_resched();
702                 }
703
704                 /* If carrier appears to come up instantly, we don't
705                  * trust it and pause so that we don't pump all our
706                  * queued console messages into the bitbucket.
707                  */
708
709                 if (time_before(jiffies, atleast)) {
710                         printk(KERN_NOTICE "%s: carrier detect appears"
711                                " untrustworthy, waiting 4 seconds\n",
712                                np->name);
713                         msleep(4000);
714                 }
715         }
716
717         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
718                 memcpy(np->local_mac, ndev->dev_addr, 6);
719
720         if (!np->local_ip) {
721                 rcu_read_lock();
722                 in_dev = __in_dev_get_rcu(ndev);
723
724                 if (!in_dev || !in_dev->ifa_list) {
725                         rcu_read_unlock();
726                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
727                                np->name, np->dev_name);
728                         err = -EDESTADDRREQ;
729                         goto release;
730                 }
731
732                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
733                 rcu_read_unlock();
734                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
735                        np->name, HIPQUAD(np->local_ip));
736         }
737
738         if (np->rx_hook) {
739                 spin_lock_irqsave(&npinfo->rx_lock, flags);
740                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
741                 npinfo->rx_np = np;
742                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
743         }
744
745         /* fill up the skb queue */
746         refill_skbs();
747
748         /* last thing to do is link it to the net device structure */
749         ndev->npinfo = npinfo;
750
751         /* avoid racing with NAPI reading npinfo */
752         synchronize_rcu();
753
754         return 0;
755
756  release:
757         if (!ndev->npinfo)
758                 kfree(npinfo);
759         np->dev = NULL;
760         dev_put(ndev);
761         return err;
762 }
763
764 static int __init netpoll_init(void)
765 {
766         skb_queue_head_init(&skb_pool);
767         return 0;
768 }
769 core_initcall(netpoll_init);
770
771 void netpoll_cleanup(struct netpoll *np)
772 {
773         struct netpoll_info *npinfo;
774         unsigned long flags;
775
776         if (np->dev) {
777                 npinfo = np->dev->npinfo;
778                 if (npinfo) {
779                         if (npinfo->rx_np == np) {
780                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
781                                 npinfo->rx_np = NULL;
782                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
783                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
784                         }
785
786                         np->dev->npinfo = NULL;
787                         if (atomic_dec_and_test(&npinfo->refcnt)) {
788                                 skb_queue_purge(&npinfo->arp_tx);
789                                 skb_queue_purge(&npinfo->txq);
790                                 cancel_rearming_delayed_work(&npinfo->tx_work);
791
792                                 /* clean after last, unfinished work */
793                                 if (!skb_queue_empty(&npinfo->txq)) {
794                                         struct sk_buff *skb;
795                                         skb = __skb_dequeue(&npinfo->txq);
796                                         kfree_skb(skb);
797                                 }
798                                 kfree(npinfo);
799                         }
800                 }
801
802                 dev_put(np->dev);
803         }
804
805         np->dev = NULL;
806 }
807
808 int netpoll_trap(void)
809 {
810         return atomic_read(&trapped);
811 }
812
813 void netpoll_set_trap(int trap)
814 {
815         if (trap)
816                 atomic_inc(&trapped);
817         else
818                 atomic_dec(&trapped);
819 }
820
821 EXPORT_SYMBOL(netpoll_set_trap);
822 EXPORT_SYMBOL(netpoll_trap);
823 EXPORT_SYMBOL(netpoll_parse_options);
824 EXPORT_SYMBOL(netpoll_setup);
825 EXPORT_SYMBOL(netpoll_cleanup);
826 EXPORT_SYMBOL(netpoll_send_udp);
827 EXPORT_SYMBOL(netpoll_poll);