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