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