SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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                 struct netdev_queue *txq;
  62
  63                 if (!netif_device_present(dev) || !netif_running(dev)) {
  64                         __kfree_skb(skb);
  65                         continue;
  66                 }
  67
  68                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  69
  70                 local_irq_save(flags);
  71                 __netif_tx_lock(txq, smp_processor_id());
  72                 if (netif_tx_queue_stopped(txq) ||
  73                     netif_tx_queue_frozen(txq) ||
  74                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
  75                         skb_queue_head(&npinfo->txq, skb);
  76                         __netif_tx_unlock(txq);
  77                         local_irq_restore(flags);
  78
  79                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  80                         return;
  81                 }
  82                 __netif_tx_unlock(txq);
  83                 local_irq_restore(flags);
  84         }
  85 }
  86
  87 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  88                             unsigned short ulen, __be32 saddr, __be32 daddr)
  89 {
  90         __wsum psum;
  91
  92         if (uh->check == 0 || skb_csum_unnecessary(skb))
  93                 return 0;
  94
  95         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
  96
  97         if (skb->ip_summed == CHECKSUM_COMPLETE &&
  98             !csum_fold(csum_add(psum, skb->csum)))
  99                 return 0;
 100
 101         skb->csum = psum;
 102
 103         return __skb_checksum_complete(skb);
 104 }
 105
 106 /*
 107  * Check whether delayed processing was scheduled for our NIC. If so,
 108  * we attempt to grab the poll lock and use ->poll() to pump the card.
 109  * If this fails, either we've recursed in ->poll() or it's already
 110  * running on another CPU.
 111  *
 112  * Note: we don't mask interrupts with this lock because we're using
 113  * trylock here and interrupts are already disabled in the softirq
 114  * case. Further, we test the poll_owner to avoid recursion on UP
 115  * systems where the lock doesn't exist.
 116  *
 117  * In cases where there is bi-directional communications, reading only
 118  * one message at a time can lead to packets being dropped by the
 119  * network adapter, forcing superfluous retries and possibly timeouts.
 120  * Thus, we set our budget to greater than 1.
 121  */
 122 static int poll_one_napi(struct netpoll_info *npinfo,
 123                          struct napi_struct *napi, int budget)
 124 {
 125         int work;
 126
 127         /* net_rx_action's ->poll() invocations and our's are
 128          * synchronized by this test which is only made while
 129          * holding the napi->poll_lock.
 130          */
 131         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 132                 return budget;
 133
 134         npinfo->rx_flags |= NETPOLL_RX_DROP;
 135         atomic_inc(&trapped);
 136         set_bit(NAPI_STATE_NPSVC, &napi->state);
 137
 138         work = napi->poll(napi, budget);
 139
 140         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 141         atomic_dec(&trapped);
 142         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 143
 144         return budget - work;
 145 }
 146
 147 static void poll_napi(struct net_device *dev)
 148 {
 149         struct napi_struct *napi;
 150         int budget = 16;
 151
 152         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 153                 if (napi->poll_owner != smp_processor_id() &&
 154                     spin_trylock(&napi->poll_lock)) {
 155                         budget = poll_one_napi(dev->npinfo, napi, budget);
 156                         spin_unlock(&napi->poll_lock);
 157
 158                         if (!budget)
 159                                 break;
 160                 }
 161         }
 162 }
 163
 164 static void service_arp_queue(struct netpoll_info *npi)
 165 {
 166         if (npi) {
 167                 struct sk_buff *skb;
 168
 169                 while ((skb = skb_dequeue(&npi->arp_tx)))
 170                         arp_reply(skb);
 171         }
 172 }
 173
 174 void netpoll_poll(struct netpoll *np)
 175 {
 176         struct net_device *dev = np->dev;
 177
 178         if (!dev || !netif_running(dev) || !dev->poll_controller)
 179                 return;
 180
 181         /* Process pending work on NIC */
 182         dev->poll_controller(dev);
 183
 184         poll_napi(dev);
 185
 186         service_arp_queue(dev->npinfo);
 187
 188         zap_completion_queue();
 189 }
 190
 191 static void refill_skbs(void)
 192 {
 193         struct sk_buff *skb;
 194         unsigned long flags;
 195
 196         spin_lock_irqsave(&skb_pool.lock, flags);
 197         while (skb_pool.qlen < MAX_SKBS) {
 198                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 199                 if (!skb)
 200                         break;
 201
 202                 __skb_queue_tail(&skb_pool, skb);
 203         }
 204         spin_unlock_irqrestore(&skb_pool.lock, flags);
 205 }
 206
 207 static void zap_completion_queue(void)
 208 {
 209         unsigned long flags;
 210         struct softnet_data *sd = &get_cpu_var(softnet_data);
 211
 212         if (sd->completion_queue) {
 213                 struct sk_buff *clist;
 214
 215                 local_irq_save(flags);
 216                 clist = sd->completion_queue;
 217                 sd->completion_queue = NULL;
 218                 local_irq_restore(flags);
 219
 220                 while (clist != NULL) {
 221                         struct sk_buff *skb = clist;
 222                         clist = clist->next;
 223                         if (skb->destructor) {
 224                                 atomic_inc(&skb->users);
 225                                 dev_kfree_skb_any(skb); /* put this one back */
 226                         } else {
 227                                 __kfree_skb(skb);
 228                         }
 229                 }
 230         }
 231
 232         put_cpu_var(softnet_data);
 233 }
 234
 235 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 236 {
 237         int count = 0;
 238         struct sk_buff *skb;
 239
 240         zap_completion_queue();
 241         refill_skbs();
 242 repeat:
 243
 244         skb = alloc_skb(len, GFP_ATOMIC);
 245         if (!skb)
 246                 skb = skb_dequeue(&skb_pool);
 247
 248         if (!skb) {
 249                 if (++count < 10) {
 250                         netpoll_poll(np);
 251                         goto repeat;
 252                 }
 253                 return NULL;
 254         }
 255
 256         atomic_set(&skb->users, 1);
 257         skb_reserve(skb, reserve);
 258         return skb;
 259 }
 260
 261 static int netpoll_owner_active(struct net_device *dev)
 262 {
 263         struct napi_struct *napi;
 264
 265         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 266                 if (napi->poll_owner == smp_processor_id())
 267                         return 1;
 268         }
 269         return 0;
 270 }
 271
 272 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 273 {
 274         int status = NETDEV_TX_BUSY;
 275         unsigned long tries;
 276         struct net_device *dev = np->dev;
 277         struct netpoll_info *npinfo = np->dev->npinfo;
 278
 279         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 280                 __kfree_skb(skb);
 281                 return;
 282         }
 283
 284         /* don't get messages out of order, and no recursion */
 285         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 286                 struct netdev_queue *txq;
 287                 unsigned long flags;
 288
 289                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 290
 291                 local_irq_save(flags);
 292                 /* try until next clock tick */
 293                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 294                      tries > 0; --tries) {
 295                         if (__netif_tx_trylock(txq)) {
 296                                 if (!netif_tx_queue_stopped(txq))
 297                                         status = dev->hard_start_xmit(skb, dev);
 298                                 __netif_tx_unlock(txq);
 299
 300                                 if (status == NETDEV_TX_OK)
 301                                         break;
 302
 303                         }
 304
 305                         /* tickle device maybe there is some cleanup */
 306                         netpoll_poll(np);
 307
 308                         udelay(USEC_PER_POLL);
 309                 }
 310                 local_irq_restore(flags);
 311         }
 312
 313         if (status != NETDEV_TX_OK) {
 314                 skb_queue_tail(&npinfo->txq, skb);
 315                 schedule_delayed_work(&npinfo->tx_work,0);
 316         }
 317 }
 318
 319 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 320 {
 321         int total_len, eth_len, ip_len, udp_len;
 322         struct sk_buff *skb;
 323         struct udphdr *udph;
 324         struct iphdr *iph;
 325         struct ethhdr *eth;
 326
 327         udp_len = len + sizeof(*udph);
 328         ip_len = eth_len = udp_len + sizeof(*iph);
 329         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 330
 331         skb = find_skb(np, total_len, total_len - len);
 332         if (!skb)
 333                 return;
 334
 335         skb_copy_to_linear_data(skb, msg, len);
 336         skb->len += len;
 337
 338         skb_push(skb, sizeof(*udph));
 339         skb_reset_transport_header(skb);
 340         udph = udp_hdr(skb);
 341         udph->source = htons(np->local_port);
 342         udph->dest = htons(np->remote_port);
 343         udph->len = htons(udp_len);
 344         udph->check = 0;
 345         udph->check = csum_tcpudp_magic(htonl(np->local_ip),
 346                                         htonl(np->remote_ip),
 347                                         udp_len, IPPROTO_UDP,
 348                                         csum_partial((unsigned char *)udph, udp_len, 0));
 349         if (udph->check == 0)
 350                 udph->check = CSUM_MANGLED_0;
 351
 352         skb_push(skb, sizeof(*iph));
 353         skb_reset_network_header(skb);
 354         iph = ip_hdr(skb);
 355
 356         /* iph->version = 4; iph->ihl = 5; */
 357         put_unaligned(0x45, (unsigned char *)iph);
 358         iph->tos      = 0;
 359         put_unaligned(htons(ip_len), &(iph->tot_len));
 360         iph->id       = 0;
 361         iph->frag_off = 0;
 362         iph->ttl      = 64;
 363         iph->protocol = IPPROTO_UDP;
 364         iph->check    = 0;
 365         put_unaligned(htonl(np->local_ip), &(iph->saddr));
 366         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
 367         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 368
 369         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 370         skb_reset_mac_header(skb);
 371         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 372         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 373         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 374
 375         skb->dev = np->dev;
 376
 377         netpoll_send_skb(np, skb);
 378 }
 379
 380 static void arp_reply(struct sk_buff *skb)
 381 {
 382         struct netpoll_info *npinfo = skb->dev->npinfo;
 383         struct arphdr *arp;
 384         unsigned char *arp_ptr;
 385         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 386         __be32 sip, tip;
 387         unsigned char *sha;
 388         struct sk_buff *send_skb;
 389         struct netpoll *np = NULL;
 390
 391         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 392                 np = npinfo->rx_np;
 393         if (!np)
 394                 return;
 395
 396         /* No arp on this interface */
 397         if (skb->dev->flags & IFF_NOARP)
 398                 return;
 399
 400         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 401                 return;
 402
 403         skb_reset_network_header(skb);
 404         skb_reset_transport_header(skb);
 405         arp = arp_hdr(skb);
 406
 407         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 408              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 409             arp->ar_pro != htons(ETH_P_IP) ||
 410             arp->ar_op != htons(ARPOP_REQUEST))
 411                 return;
 412
 413         arp_ptr = (unsigned char *)(arp+1);
 414         /* save the location of the src hw addr */
 415         sha = arp_ptr;
 416         arp_ptr += skb->dev->addr_len;
 417         memcpy(&sip, arp_ptr, 4);
 418         arp_ptr += 4;
 419         /* if we actually cared about dst hw addr, it would get copied here */
 420         arp_ptr += skb->dev->addr_len;
 421         memcpy(&tip, arp_ptr, 4);
 422
 423         /* Should we ignore arp? */
 424         if (tip != htonl(np->local_ip) ||
 425             ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 426                 return;
 427
 428         size = arp_hdr_len(skb->dev);
 429         send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 430                             LL_RESERVED_SPACE(np->dev));
 431
 432         if (!send_skb)
 433                 return;
 434
 435         skb_reset_network_header(send_skb);
 436         arp = (struct arphdr *) skb_put(send_skb, size);
 437         send_skb->dev = skb->dev;
 438         send_skb->protocol = htons(ETH_P_ARP);
 439
 440         /* Fill the device header for the ARP frame */
 441         if (dev_hard_header(send_skb, skb->dev, ptype,
 442                             sha, np->dev->dev_addr,
 443                             send_skb->len) < 0) {
 444                 kfree_skb(send_skb);
 445                 return;
 446         }
 447
 448         /*
 449          * Fill out the arp protocol part.
 450          *
 451          * we only support ethernet device type,
 452          * which (according to RFC 1390) should always equal 1 (Ethernet).
 453          */
 454
 455         arp->ar_hrd = htons(np->dev->type);
 456         arp->ar_pro = htons(ETH_P_IP);
 457         arp->ar_hln = np->dev->addr_len;
 458         arp->ar_pln = 4;
 459         arp->ar_op = htons(type);
 460
 461         arp_ptr=(unsigned char *)(arp + 1);
 462         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 463         arp_ptr += np->dev->addr_len;
 464         memcpy(arp_ptr, &tip, 4);
 465         arp_ptr += 4;
 466         memcpy(arp_ptr, sha, np->dev->addr_len);
 467         arp_ptr += np->dev->addr_len;
 468         memcpy(arp_ptr, &sip, 4);
 469
 470         netpoll_send_skb(np, send_skb);
 471 }
 472
 473 int __netpoll_rx(struct sk_buff *skb)
 474 {
 475         int proto, len, ulen;
 476         struct iphdr *iph;
 477         struct udphdr *uh;
 478         struct netpoll_info *npi = skb->dev->npinfo;
 479         struct netpoll *np = npi->rx_np;
 480
 481         if (!np)
 482                 goto out;
 483         if (skb->dev->type != ARPHRD_ETHER)
 484                 goto out;
 485
 486         /* check if netpoll clients need ARP */
 487         if (skb->protocol == htons(ETH_P_ARP) &&
 488             atomic_read(&trapped)) {
 489                 skb_queue_tail(&npi->arp_tx, skb);
 490                 return 1;
 491         }
 492
 493         proto = ntohs(eth_hdr(skb)->h_proto);
 494         if (proto != ETH_P_IP)
 495                 goto out;
 496         if (skb->pkt_type == PACKET_OTHERHOST)
 497                 goto out;
 498         if (skb_shared(skb))
 499                 goto out;
 500
 501         iph = (struct iphdr *)skb->data;
 502         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 503                 goto out;
 504         if (iph->ihl < 5 || iph->version != 4)
 505                 goto out;
 506         if (!pskb_may_pull(skb, iph->ihl*4))
 507                 goto out;
 508         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 509                 goto out;
 510
 511         len = ntohs(iph->tot_len);
 512         if (skb->len < len || len < iph->ihl*4)
 513                 goto out;
 514
 515         /*
 516          * Our transport medium may have padded the buffer out.
 517          * Now We trim to the true length of the frame.
 518          */
 519         if (pskb_trim_rcsum(skb, len))
 520                 goto out;
 521
 522         if (iph->protocol != IPPROTO_UDP)
 523                 goto out;
 524
 525         len -= iph->ihl*4;
 526         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 527         ulen = ntohs(uh->len);
 528
 529         if (ulen != len)
 530                 goto out;
 531         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 532                 goto out;
 533         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
 534                 goto out;
 535         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
 536                 goto out;
 537         if (np->local_port && np->local_port != ntohs(uh->dest))
 538                 goto out;
 539
 540         np->rx_hook(np, ntohs(uh->source),
 541                     (char *)(uh+1),
 542                     ulen - sizeof(struct udphdr));
 543
 544         kfree_skb(skb);
 545         return 1;
 546
 547 out:
 548         if (atomic_read(&trapped)) {
 549                 kfree_skb(skb);
 550                 return 1;
 551         }
 552
 553         return 0;
 554 }
 555
 556 void netpoll_print_options(struct netpoll *np)
 557 {
 558         DECLARE_MAC_BUF(mac);
 559         printk(KERN_INFO "%s: local port %d\n",
 560                          np->name, np->local_port);
 561         printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 562                          np->name, HIPQUAD(np->local_ip));
 563         printk(KERN_INFO "%s: interface %s\n",
 564                          np->name, np->dev_name);
 565         printk(KERN_INFO "%s: remote port %d\n",
 566                          np->name, np->remote_port);
 567         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
 568                          np->name, HIPQUAD(np->remote_ip));
 569         printk(KERN_INFO "%s: remote ethernet address %s\n",
 570                          np->name, print_mac(mac, np->remote_mac));
 571 }
 572
 573 int netpoll_parse_options(struct netpoll *np, char *opt)
 574 {
 575         char *cur=opt, *delim;
 576
 577         if (*cur != '@') {
 578                 if ((delim = strchr(cur, '@')) == NULL)
 579                         goto parse_failed;
 580                 *delim = 0;
 581                 np->local_port = simple_strtol(cur, NULL, 10);
 582                 cur = delim;
 583         }
 584         cur++;
 585
 586         if (*cur != '/') {
 587                 if ((delim = strchr(cur, '/')) == NULL)
 588                         goto parse_failed;
 589                 *delim = 0;
 590                 np->local_ip = ntohl(in_aton(cur));
 591                 cur = delim;
 592         }
 593         cur++;
 594
 595         if (*cur != ',') {
 596                 /* parse out dev name */
 597                 if ((delim = strchr(cur, ',')) == NULL)
 598                         goto parse_failed;
 599                 *delim = 0;
 600                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 601                 cur = delim;
 602         }
 603         cur++;
 604
 605         if (*cur != '@') {
 606                 /* dst port */
 607                 if ((delim = strchr(cur, '@')) == NULL)
 608                         goto parse_failed;
 609                 *delim = 0;
 610                 np->remote_port = simple_strtol(cur, NULL, 10);
 611                 cur = delim;
 612         }
 613         cur++;
 614
 615         /* dst ip */
 616         if ((delim = strchr(cur, '/')) == NULL)
 617                 goto parse_failed;
 618         *delim = 0;
 619         np->remote_ip = ntohl(in_aton(cur));
 620         cur = delim + 1;
 621
 622         if (*cur != 0) {
 623                 /* MAC address */
 624                 if ((delim = strchr(cur, ':')) == NULL)
 625                         goto parse_failed;
 626                 *delim = 0;
 627                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 628                 cur = delim + 1;
 629                 if ((delim = strchr(cur, ':')) == NULL)
 630                         goto parse_failed;
 631                 *delim = 0;
 632                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 633                 cur = delim + 1;
 634                 if ((delim = strchr(cur, ':')) == NULL)
 635                         goto parse_failed;
 636                 *delim = 0;
 637                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 638                 cur = delim + 1;
 639                 if ((delim = strchr(cur, ':')) == NULL)
 640                         goto parse_failed;
 641                 *delim = 0;
 642                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 643                 cur = delim + 1;
 644                 if ((delim = strchr(cur, ':')) == NULL)
 645                         goto parse_failed;
 646                 *delim = 0;
 647                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 648                 cur = delim + 1;
 649                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 650         }
 651
 652         netpoll_print_options(np);
 653
 654         return 0;
 655
 656  parse_failed:
 657         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 658                np->name, cur);
 659         return -1;
 660 }
 661
 662 int netpoll_setup(struct netpoll *np)
 663 {
 664         struct net_device *ndev = NULL;
 665         struct in_device *in_dev;
 666         struct netpoll_info *npinfo;
 667         unsigned long flags;
 668         int err;
 669
 670         if (np->dev_name)
 671                 ndev = dev_get_by_name(&init_net, np->dev_name);
 672         if (!ndev) {
 673                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 674                        np->name, np->dev_name);
 675                 return -ENODEV;
 676         }
 677
 678         np->dev = ndev;
 679         if (!ndev->npinfo) {
 680                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 681                 if (!npinfo) {
 682                         err = -ENOMEM;
 683                         goto release;
 684                 }
 685
 686                 npinfo->rx_flags = 0;
 687                 npinfo->rx_np = NULL;
 688
 689                 spin_lock_init(&npinfo->rx_lock);
 690                 skb_queue_head_init(&npinfo->arp_tx);
 691                 skb_queue_head_init(&npinfo->txq);
 692                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 693
 694                 atomic_set(&npinfo->refcnt, 1);
 695         } else {
 696                 npinfo = ndev->npinfo;
 697                 atomic_inc(&npinfo->refcnt);
 698         }
 699
 700         if (!ndev->poll_controller) {
 701                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 702                        np->name, np->dev_name);
 703                 err = -ENOTSUPP;
 704                 goto release;
 705         }
 706
 707         if (!netif_running(ndev)) {
 708                 unsigned long atmost, atleast;
 709
 710                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 711                        np->name, np->dev_name);
 712
 713                 rtnl_lock();
 714                 err = dev_open(ndev);
 715                 rtnl_unlock();
 716
 717                 if (err) {
 718                         printk(KERN_ERR "%s: failed to open %s\n",
 719                                np->name, ndev->name);
 720                         goto release;
 721                 }
 722
 723                 atleast = jiffies + HZ/10;
 724                 atmost = jiffies + 4*HZ;
 725                 while (!netif_carrier_ok(ndev)) {
 726                         if (time_after(jiffies, atmost)) {
 727                                 printk(KERN_NOTICE
 728                                        "%s: timeout waiting for carrier\n",
 729                                        np->name);
 730                                 break;
 731                         }
 732                         cond_resched();
 733                 }
 734
 735                 /* If carrier appears to come up instantly, we don't
 736                  * trust it and pause so that we don't pump all our
 737                  * queued console messages into the bitbucket.
 738                  */
 739
 740                 if (time_before(jiffies, atleast)) {
 741                         printk(KERN_NOTICE "%s: carrier detect appears"
 742                                " untrustworthy, waiting 4 seconds\n",
 743                                np->name);
 744                         msleep(4000);
 745                 }
 746         }
 747
 748         if (!np->local_ip) {
 749                 rcu_read_lock();
 750                 in_dev = __in_dev_get_rcu(ndev);
 751
 752                 if (!in_dev || !in_dev->ifa_list) {
 753                         rcu_read_unlock();
 754                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 755                                np->name, np->dev_name);
 756                         err = -EDESTADDRREQ;
 757                         goto release;
 758                 }
 759
 760                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
 761                 rcu_read_unlock();
 762                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
 763                        np->name, HIPQUAD(np->local_ip));
 764         }
 765
 766         if (np->rx_hook) {
 767                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 768                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 769                 npinfo->rx_np = np;
 770                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 771         }
 772
 773         /* fill up the skb queue */
 774         refill_skbs();
 775
 776         /* last thing to do is link it to the net device structure */
 777         ndev->npinfo = npinfo;
 778
 779         /* avoid racing with NAPI reading npinfo */
 780         synchronize_rcu();
 781
 782         return 0;
 783
 784  release:
 785         if (!ndev->npinfo)
 786                 kfree(npinfo);
 787         np->dev = NULL;
 788         dev_put(ndev);
 789         return err;
 790 }
 791
 792 static int __init netpoll_init(void)
 793 {
 794         skb_queue_head_init(&skb_pool);
 795         return 0;
 796 }
 797 core_initcall(netpoll_init);
 798
 799 void netpoll_cleanup(struct netpoll *np)
 800 {
 801         struct netpoll_info *npinfo;
 802         unsigned long flags;
 803
 804         if (np->dev) {
 805                 npinfo = np->dev->npinfo;
 806                 if (npinfo) {
 807                         if (npinfo->rx_np == np) {
 808                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 809                                 npinfo->rx_np = NULL;
 810                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 811                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 812                         }
 813
 814                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 815                                 skb_queue_purge(&npinfo->arp_tx);
 816                                 skb_queue_purge(&npinfo->txq);
 817                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 818
 819                                 /* clean after last, unfinished work */
 820                                 __skb_queue_purge(&npinfo->txq);
 821                                 kfree(npinfo);
 822                                 np->dev->npinfo = NULL;
 823                         }
 824                 }
 825
 826                 dev_put(np->dev);
 827         }
 828
 829         np->dev = NULL;
 830 }
 831
 832 int netpoll_trap(void)
 833 {
 834         return atomic_read(&trapped);
 835 }
 836
 837 void netpoll_set_trap(int trap)
 838 {
 839         if (trap)
 840                 atomic_inc(&trapped);
 841         else
 842                 atomic_dec(&trapped);
 843 }
 844
 845 EXPORT_SYMBOL(netpoll_set_trap);
 846 EXPORT_SYMBOL(netpoll_trap);
 847 EXPORT_SYMBOL(netpoll_print_options);
 848 EXPORT_SYMBOL(netpoll_parse_options);
 849 EXPORT_SYMBOL(netpoll_setup);
 850 EXPORT_SYMBOL(netpoll_cleanup);
 851 EXPORT_SYMBOL(netpoll_send_udp);
 852 EXPORT_SYMBOL(netpoll_poll);