[NETPOLL]: Use skb_queue_purge().
[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/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)) ||
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 int poll_one_napi(struct netpoll_info *npinfo,
120                          struct napi_struct *napi, int budget)
121 {
122         int work;
123
124         /* net_rx_action's ->poll() invocations and our's are
125          * synchronized by this test which is only made while
126          * holding the napi->poll_lock.
127          */
128         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
129                 return budget;
130
131         npinfo->rx_flags |= NETPOLL_RX_DROP;
132         atomic_inc(&trapped);
133
134         work = napi->poll(napi, budget);
135
136         atomic_dec(&trapped);
137         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
138
139         return budget - work;
140 }
141
142 static void poll_napi(struct netpoll *np)
143 {
144         struct netpoll_info *npinfo = np->dev->npinfo;
145         struct napi_struct *napi;
146         int budget = 16;
147
148         list_for_each_entry(napi, &np->dev->napi_list, dev_list) {
149                 if (napi->poll_owner != smp_processor_id() &&
150                     spin_trylock(&napi->poll_lock)) {
151                         budget = poll_one_napi(npinfo, napi, budget);
152                         spin_unlock(&napi->poll_lock);
153
154                         if (!budget)
155                                 break;
156                 }
157         }
158 }
159
160 static void service_arp_queue(struct netpoll_info *npi)
161 {
162         struct sk_buff *skb;
163
164         if (unlikely(!npi))
165                 return;
166
167         skb = skb_dequeue(&npi->arp_tx);
168
169         while (skb != NULL) {
170                 arp_reply(skb);
171                 skb = skb_dequeue(&npi->arp_tx);
172         }
173 }
174
175 void netpoll_poll(struct netpoll *np)
176 {
177         if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
178                 return;
179
180         /* Process pending work on NIC */
181         np->dev->poll_controller(np->dev);
182         if (!list_empty(&np->dev->napi_list))
183                 poll_napi(np);
184
185         service_arp_queue(np->dev->npinfo);
186
187         zap_completion_queue();
188 }
189
190 static void refill_skbs(void)
191 {
192         struct sk_buff *skb;
193         unsigned long flags;
194
195         spin_lock_irqsave(&skb_pool.lock, flags);
196         while (skb_pool.qlen < MAX_SKBS) {
197                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
198                 if (!skb)
199                         break;
200
201                 __skb_queue_tail(&skb_pool, skb);
202         }
203         spin_unlock_irqrestore(&skb_pool.lock, flags);
204 }
205
206 static void zap_completion_queue(void)
207 {
208         unsigned long flags;
209         struct softnet_data *sd = &get_cpu_var(softnet_data);
210
211         if (sd->completion_queue) {
212                 struct sk_buff *clist;
213
214                 local_irq_save(flags);
215                 clist = sd->completion_queue;
216                 sd->completion_queue = NULL;
217                 local_irq_restore(flags);
218
219                 while (clist != NULL) {
220                         struct sk_buff *skb = clist;
221                         clist = clist->next;
222                         if (skb->destructor)
223                                 dev_kfree_skb_any(skb); /* put this one back */
224                         else
225                                 __kfree_skb(skb);
226                 }
227         }
228
229         put_cpu_var(softnet_data);
230 }
231
232 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
233 {
234         int count = 0;
235         struct sk_buff *skb;
236
237         zap_completion_queue();
238         refill_skbs();
239 repeat:
240
241         skb = alloc_skb(len, GFP_ATOMIC);
242         if (!skb)
243                 skb = skb_dequeue(&skb_pool);
244
245         if (!skb) {
246                 if (++count < 10) {
247                         netpoll_poll(np);
248                         goto repeat;
249                 }
250                 return NULL;
251         }
252
253         atomic_set(&skb->users, 1);
254         skb_reserve(skb, reserve);
255         return skb;
256 }
257
258 static int netpoll_owner_active(struct net_device *dev)
259 {
260         struct napi_struct *napi;
261
262         list_for_each_entry(napi, &dev->napi_list, dev_list) {
263                 if (napi->poll_owner == smp_processor_id())
264                         return 1;
265         }
266         return 0;
267 }
268
269 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
270 {
271         int status = NETDEV_TX_BUSY;
272         unsigned long tries;
273         struct net_device *dev = np->dev;
274         struct netpoll_info *npinfo = np->dev->npinfo;
275
276         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
277                 __kfree_skb(skb);
278                 return;
279         }
280
281         /* don't get messages out of order, and no recursion */
282         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
283                 unsigned long flags;
284
285                 local_irq_save(flags);
286                 /* try until next clock tick */
287                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
288                      tries > 0; --tries) {
289                         if (netif_tx_trylock(dev)) {
290                                 if (!netif_queue_stopped(dev) &&
291                                     !netif_subqueue_stopped(dev, skb))
292                                         status = dev->hard_start_xmit(skb, dev);
293                                 netif_tx_unlock(dev);
294
295                                 if (status == NETDEV_TX_OK)
296                                         break;
297
298                         }
299
300                         /* tickle device maybe there is some cleanup */
301                         netpoll_poll(np);
302
303                         udelay(USEC_PER_POLL);
304                 }
305                 local_irq_restore(flags);
306         }
307
308         if (status != NETDEV_TX_OK) {
309                 skb_queue_tail(&npinfo->txq, skb);
310                 schedule_delayed_work(&npinfo->tx_work,0);
311         }
312 }
313
314 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
315 {
316         int total_len, eth_len, ip_len, udp_len;
317         struct sk_buff *skb;
318         struct udphdr *udph;
319         struct iphdr *iph;
320         struct ethhdr *eth;
321
322         udp_len = len + sizeof(*udph);
323         ip_len = eth_len = udp_len + sizeof(*iph);
324         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
325
326         skb = find_skb(np, total_len, total_len - len);
327         if (!skb)
328                 return;
329
330         skb_copy_to_linear_data(skb, msg, len);
331         skb->len += len;
332
333         skb_push(skb, sizeof(*udph));
334         skb_reset_transport_header(skb);
335         udph = udp_hdr(skb);
336         udph->source = htons(np->local_port);
337         udph->dest = htons(np->remote_port);
338         udph->len = htons(udp_len);
339         udph->check = 0;
340         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
341                                         htonl(np->remote_ip),
342                                         udp_len, IPPROTO_UDP,
343                                         csum_partial((unsigned char *)udph, udp_len, 0));
344         if (udph->check == 0)
345                 udph->check = CSUM_MANGLED_0;
346
347         skb_push(skb, sizeof(*iph));
348         skb_reset_network_header(skb);
349         iph = ip_hdr(skb);
350
351         /* iph->version = 4; iph->ihl = 5; */
352         put_unaligned(0x45, (unsigned char *)iph);
353         iph->tos      = 0;
354         put_unaligned(htons(ip_len), &(iph->tot_len));
355         iph->id       = 0;
356         iph->frag_off = 0;
357         iph->ttl      = 64;
358         iph->protocol = IPPROTO_UDP;
359         iph->check    = 0;
360         put_unaligned(htonl(np->local_ip), &(iph->saddr));
361         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
362         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
363
364         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
365         skb_reset_mac_header(skb);
366         skb->protocol = eth->h_proto = htons(ETH_P_IP);
367         memcpy(eth->h_source, np->local_mac, 6);
368         memcpy(eth->h_dest, np->remote_mac, 6);
369
370         skb->dev = np->dev;
371
372         netpoll_send_skb(np, skb);
373 }
374
375 static void arp_reply(struct sk_buff *skb)
376 {
377         struct netpoll_info *npinfo = skb->dev->npinfo;
378         struct arphdr *arp;
379         unsigned char *arp_ptr;
380         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
381         __be32 sip, tip;
382         unsigned char *sha;
383         struct sk_buff *send_skb;
384         struct netpoll *np = NULL;
385
386         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
387                 np = npinfo->rx_np;
388         if (!np)
389                 return;
390
391         /* No arp on this interface */
392         if (skb->dev->flags & IFF_NOARP)
393                 return;
394
395         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
396                                  (2 * skb->dev->addr_len) +
397                                  (2 * sizeof(u32)))))
398                 return;
399
400         skb_reset_network_header(skb);
401         skb_reset_transport_header(skb);
402         arp = arp_hdr(skb);
403
404         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
405              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
406             arp->ar_pro != htons(ETH_P_IP) ||
407             arp->ar_op != htons(ARPOP_REQUEST))
408                 return;
409
410         arp_ptr = (unsigned char *)(arp+1);
411         /* save the location of the src hw addr */
412         sha = arp_ptr;
413         arp_ptr += skb->dev->addr_len;
414         memcpy(&sip, arp_ptr, 4);
415         arp_ptr += 4;
416         /* if we actually cared about dst hw addr, it would get copied here */
417         arp_ptr += skb->dev->addr_len;
418         memcpy(&tip, arp_ptr, 4);
419
420         /* Should we ignore arp? */
421         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
422                 return;
423
424         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
425         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
426                             LL_RESERVED_SPACE(np->dev));
427
428         if (!send_skb)
429                 return;
430
431         skb_reset_network_header(send_skb);
432         arp = (struct arphdr *) skb_put(send_skb, size);
433         send_skb->dev = skb->dev;
434         send_skb->protocol = htons(ETH_P_ARP);
435
436         /* Fill the device header for the ARP frame */
437         if (dev_hard_header(send_skb, skb->dev, ptype,
438                             sha, np->local_mac,
439                             send_skb->len) < 0) {
440                 kfree_skb(send_skb);
441                 return;
442         }
443
444         /*
445          * Fill out the arp protocol part.
446          *
447          * we only support ethernet device type,
448          * which (according to RFC 1390) should always equal 1 (Ethernet).
449          */
450
451         arp->ar_hrd = htons(np->dev->type);
452         arp->ar_pro = htons(ETH_P_IP);
453         arp->ar_hln = np->dev->addr_len;
454         arp->ar_pln = 4;
455         arp->ar_op = htons(type);
456
457         arp_ptr=(unsigned char *)(arp + 1);
458         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
459         arp_ptr += np->dev->addr_len;
460         memcpy(arp_ptr, &tip, 4);
461         arp_ptr += 4;
462         memcpy(arp_ptr, sha, np->dev->addr_len);
463         arp_ptr += np->dev->addr_len;
464         memcpy(arp_ptr, &sip, 4);
465
466         netpoll_send_skb(np, send_skb);
467 }
468
469 int __netpoll_rx(struct sk_buff *skb)
470 {
471         int proto, len, ulen;
472         struct iphdr *iph;
473         struct udphdr *uh;
474         struct netpoll_info *npi = skb->dev->npinfo;
475         struct netpoll *np = npi->rx_np;
476
477         if (!np)
478                 goto out;
479         if (skb->dev->type != ARPHRD_ETHER)
480                 goto out;
481
482         /* check if netpoll clients need ARP */
483         if (skb->protocol == htons(ETH_P_ARP) &&
484             atomic_read(&trapped)) {
485                 skb_queue_tail(&npi->arp_tx, skb);
486                 return 1;
487         }
488
489         proto = ntohs(eth_hdr(skb)->h_proto);
490         if (proto != ETH_P_IP)
491                 goto out;
492         if (skb->pkt_type == PACKET_OTHERHOST)
493                 goto out;
494         if (skb_shared(skb))
495                 goto out;
496
497         iph = (struct iphdr *)skb->data;
498         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
499                 goto out;
500         if (iph->ihl < 5 || iph->version != 4)
501                 goto out;
502         if (!pskb_may_pull(skb, iph->ihl*4))
503                 goto out;
504         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
505                 goto out;
506
507         len = ntohs(iph->tot_len);
508         if (skb->len < len || len < iph->ihl*4)
509                 goto out;
510
511         /*
512          * Our transport medium may have padded the buffer out.
513          * Now We trim to the true length of the frame.
514          */
515         if (pskb_trim_rcsum(skb, len))
516                 goto out;
517
518         if (iph->protocol != IPPROTO_UDP)
519                 goto out;
520
521         len -= iph->ihl*4;
522         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
523         ulen = ntohs(uh->len);
524
525         if (ulen != len)
526                 goto out;
527         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
528                 goto out;
529         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
530                 goto out;
531         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
532                 goto out;
533         if (np->local_port && np->local_port != ntohs(uh->dest))
534                 goto out;
535
536         np->rx_hook(np, ntohs(uh->source),
537                     (char *)(uh+1),
538                     ulen - sizeof(struct udphdr));
539
540         kfree_skb(skb);
541         return 1;
542
543 out:
544         if (atomic_read(&trapped)) {
545                 kfree_skb(skb);
546                 return 1;
547         }
548
549         return 0;
550 }
551
552 void netpoll_print_options(struct netpoll *np)
553 {
554         DECLARE_MAC_BUF(mac);
555         printk(KERN_INFO "%s: local port %d\n",
556                          np->name, np->local_port);
557         printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
558                          np->name, HIPQUAD(np->local_ip));
559         printk(KERN_INFO "%s: interface %s\n",
560                          np->name, np->dev_name);
561         printk(KERN_INFO "%s: remote port %d\n",
562                          np->name, np->remote_port);
563         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
564                          np->name, HIPQUAD(np->remote_ip));
565         printk(KERN_INFO "%s: remote ethernet address %s\n",
566                          np->name, print_mac(mac, np->remote_mac));
567 }
568
569 int netpoll_parse_options(struct netpoll *np, char *opt)
570 {
571         char *cur=opt, *delim;
572
573         if (*cur != '@') {
574                 if ((delim = strchr(cur, '@')) == NULL)
575                         goto parse_failed;
576                 *delim = 0;
577                 np->local_port = simple_strtol(cur, NULL, 10);
578                 cur = delim;
579         }
580         cur++;
581
582         if (*cur != '/') {
583                 if ((delim = strchr(cur, '/')) == NULL)
584                         goto parse_failed;
585                 *delim = 0;
586                 np->local_ip = ntohl(in_aton(cur));
587                 cur = delim;
588         }
589         cur++;
590
591         if (*cur != ',') {
592                 /* parse out dev name */
593                 if ((delim = strchr(cur, ',')) == NULL)
594                         goto parse_failed;
595                 *delim = 0;
596                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
597                 cur = delim;
598         }
599         cur++;
600
601         if (*cur != '@') {
602                 /* dst port */
603                 if ((delim = strchr(cur, '@')) == NULL)
604                         goto parse_failed;
605                 *delim = 0;
606                 np->remote_port = simple_strtol(cur, NULL, 10);
607                 cur = delim;
608         }
609         cur++;
610
611         /* dst ip */
612         if ((delim = strchr(cur, '/')) == NULL)
613                 goto parse_failed;
614         *delim = 0;
615         np->remote_ip = ntohl(in_aton(cur));
616         cur = delim + 1;
617
618         if (*cur != 0) {
619                 /* MAC address */
620                 if ((delim = strchr(cur, ':')) == NULL)
621                         goto parse_failed;
622                 *delim = 0;
623                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
624                 cur = delim + 1;
625                 if ((delim = strchr(cur, ':')) == NULL)
626                         goto parse_failed;
627                 *delim = 0;
628                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
629                 cur = delim + 1;
630                 if ((delim = strchr(cur, ':')) == NULL)
631                         goto parse_failed;
632                 *delim = 0;
633                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
634                 cur = delim + 1;
635                 if ((delim = strchr(cur, ':')) == NULL)
636                         goto parse_failed;
637                 *delim = 0;
638                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
639                 cur = delim + 1;
640                 if ((delim = strchr(cur, ':')) == NULL)
641                         goto parse_failed;
642                 *delim = 0;
643                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
644                 cur = delim + 1;
645                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
646         }
647
648         netpoll_print_options(np);
649
650         return 0;
651
652  parse_failed:
653         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
654                np->name, cur);
655         return -1;
656 }
657
658 int netpoll_setup(struct netpoll *np)
659 {
660         struct net_device *ndev = NULL;
661         struct in_device *in_dev;
662         struct netpoll_info *npinfo;
663         unsigned long flags;
664         int err;
665
666         if (np->dev_name)
667                 ndev = dev_get_by_name(&init_net, np->dev_name);
668         if (!ndev) {
669                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
670                        np->name, np->dev_name);
671                 return -ENODEV;
672         }
673
674         np->dev = ndev;
675         if (!ndev->npinfo) {
676                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
677                 if (!npinfo) {
678                         err = -ENOMEM;
679                         goto release;
680                 }
681
682                 npinfo->rx_flags = 0;
683                 npinfo->rx_np = NULL;
684
685                 spin_lock_init(&npinfo->rx_lock);
686                 skb_queue_head_init(&npinfo->arp_tx);
687                 skb_queue_head_init(&npinfo->txq);
688                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
689
690                 atomic_set(&npinfo->refcnt, 1);
691         } else {
692                 npinfo = ndev->npinfo;
693                 atomic_inc(&npinfo->refcnt);
694         }
695
696         if (!ndev->poll_controller) {
697                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
698                        np->name, np->dev_name);
699                 err = -ENOTSUPP;
700                 goto release;
701         }
702
703         if (!netif_running(ndev)) {
704                 unsigned long atmost, atleast;
705
706                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
707                        np->name, np->dev_name);
708
709                 rtnl_lock();
710                 err = dev_open(ndev);
711                 rtnl_unlock();
712
713                 if (err) {
714                         printk(KERN_ERR "%s: failed to open %s\n",
715                                np->name, ndev->name);
716                         goto release;
717                 }
718
719                 atleast = jiffies + HZ/10;
720                 atmost = jiffies + 4*HZ;
721                 while (!netif_carrier_ok(ndev)) {
722                         if (time_after(jiffies, atmost)) {
723                                 printk(KERN_NOTICE
724                                        "%s: timeout waiting for carrier\n",
725                                        np->name);
726                                 break;
727                         }
728                         cond_resched();
729                 }
730
731                 /* If carrier appears to come up instantly, we don't
732                  * trust it and pause so that we don't pump all our
733                  * queued console messages into the bitbucket.
734                  */
735
736                 if (time_before(jiffies, atleast)) {
737                         printk(KERN_NOTICE "%s: carrier detect appears"
738                                " untrustworthy, waiting 4 seconds\n",
739                                np->name);
740                         msleep(4000);
741                 }
742         }
743
744         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
745                 memcpy(np->local_mac, ndev->dev_addr, 6);
746
747         if (!np->local_ip) {
748                 rcu_read_lock();
749                 in_dev = __in_dev_get_rcu(ndev);
750
751                 if (!in_dev || !in_dev->ifa_list) {
752                         rcu_read_unlock();
753                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
754                                np->name, np->dev_name);
755                         err = -EDESTADDRREQ;
756                         goto release;
757                 }
758
759                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
760                 rcu_read_unlock();
761                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
762                        np->name, HIPQUAD(np->local_ip));
763         }
764
765         if (np->rx_hook) {
766                 spin_lock_irqsave(&npinfo->rx_lock, flags);
767                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
768                 npinfo->rx_np = np;
769                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
770         }
771
772         /* fill up the skb queue */
773         refill_skbs();
774
775         /* last thing to do is link it to the net device structure */
776         ndev->npinfo = npinfo;
777
778         /* avoid racing with NAPI reading npinfo */
779         synchronize_rcu();
780
781         return 0;
782
783  release:
784         if (!ndev->npinfo)
785                 kfree(npinfo);
786         np->dev = NULL;
787         dev_put(ndev);
788         return err;
789 }
790
791 static int __init netpoll_init(void)
792 {
793         skb_queue_head_init(&skb_pool);
794         return 0;
795 }
796 core_initcall(netpoll_init);
797
798 void netpoll_cleanup(struct netpoll *np)
799 {
800         struct netpoll_info *npinfo;
801         unsigned long flags;
802
803         if (np->dev) {
804                 npinfo = np->dev->npinfo;
805                 if (npinfo) {
806                         if (npinfo->rx_np == np) {
807                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
808                                 npinfo->rx_np = NULL;
809                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
810                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
811                         }
812
813                         if (atomic_dec_and_test(&npinfo->refcnt)) {
814                                 skb_queue_purge(&npinfo->arp_tx);
815                                 skb_queue_purge(&npinfo->txq);
816                                 cancel_rearming_delayed_work(&npinfo->tx_work);
817
818                                 /* clean after last, unfinished work */
819                                 __skb_queue_purge(&npinfo->txq);
820                                 kfree(npinfo);
821                                 np->dev->npinfo = NULL;
822                         }
823                 }
824
825                 dev_put(np->dev);
826         }
827
828         np->dev = NULL;
829 }
830
831 int netpoll_trap(void)
832 {
833         return atomic_read(&trapped);
834 }
835
836 void netpoll_set_trap(int trap)
837 {
838         if (trap)
839                 atomic_inc(&trapped);
840         else
841                 atomic_dec(&trapped);
842 }
843
844 EXPORT_SYMBOL(netpoll_set_trap);
845 EXPORT_SYMBOL(netpoll_trap);
846 EXPORT_SYMBOL(netpoll_print_options);
847 EXPORT_SYMBOL(netpoll_parse_options);
848 EXPORT_SYMBOL(netpoll_setup);
849 EXPORT_SYMBOL(netpoll_cleanup);
850 EXPORT_SYMBOL(netpoll_send_udp);
851 EXPORT_SYMBOL(netpoll_poll);