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/moduleparam.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 <linux/slab.h>
  26 #include <linux/export.h>
  27 #include <net/tcp.h>
  28 #include <net/udp.h>
  29 #include <asm/unaligned.h>
  30 #include <trace/events/napi.h>
  31
  32 /*
  33  * We maintain a small pool of fully-sized skbs, to make sure the
  34  * message gets out even in extreme OOM situations.
  35  */
  36
  37 #define MAX_UDP_CHUNK 1460
  38 #define MAX_SKBS 32
  39
  40 static struct sk_buff_head skb_pool;
  41
  42 static atomic_t trapped;
  43
  44 #define USEC_PER_POLL   50
  45 #define NETPOLL_RX_ENABLED  1
  46 #define NETPOLL_RX_DROP     2
  47
  48 #define MAX_SKB_SIZE \
  49                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  50                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  51
  52 static void zap_completion_queue(void);
  53 static void arp_reply(struct sk_buff *skb);
  54
  55 static unsigned int carrier_timeout = 4;
  56 module_param(carrier_timeout, uint, 0644);
  57
  58 static void queue_process(struct work_struct *work)
  59 {
  60         struct netpoll_info *npinfo =
  61                 container_of(work, struct netpoll_info, tx_work.work);
  62         struct sk_buff *skb;
  63         unsigned long flags;
  64
  65         while ((skb = skb_dequeue(&npinfo->txq))) {
  66                 struct net_device *dev = skb->dev;
  67                 const struct net_device_ops *ops = dev->netdev_ops;
  68                 struct netdev_queue *txq;
  69
  70                 if (!netif_device_present(dev) || !netif_running(dev)) {
  71                         __kfree_skb(skb);
  72                         continue;
  73                 }
  74
  75                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  76
  77                 local_irq_save(flags);
  78                 __netif_tx_lock(txq, smp_processor_id());
  79                 if (netif_tx_queue_frozen_or_stopped(txq) ||
  80                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  81                         skb_queue_head(&npinfo->txq, skb);
  82                         __netif_tx_unlock(txq);
  83                         local_irq_restore(flags);
  84
  85                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  86                         return;
  87                 }
  88                 __netif_tx_unlock(txq);
  89                 local_irq_restore(flags);
  90         }
  91 }
  92
  93 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  94                             unsigned short ulen, __be32 saddr, __be32 daddr)
  95 {
  96         __wsum psum;
  97
  98         if (uh->check == 0 || skb_csum_unnecessary(skb))
  99                 return 0;
 100
 101         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 102
 103         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 104             !csum_fold(csum_add(psum, skb->csum)))
 105                 return 0;
 106
 107         skb->csum = psum;
 108
 109         return __skb_checksum_complete(skb);
 110 }
 111
 112 /*
 113  * Check whether delayed processing was scheduled for our NIC. If so,
 114  * we attempt to grab the poll lock and use ->poll() to pump the card.
 115  * If this fails, either we've recursed in ->poll() or it's already
 116  * running on another CPU.
 117  *
 118  * Note: we don't mask interrupts with this lock because we're using
 119  * trylock here and interrupts are already disabled in the softirq
 120  * case. Further, we test the poll_owner to avoid recursion on UP
 121  * systems where the lock doesn't exist.
 122  *
 123  * In cases where there is bi-directional communications, reading only
 124  * one message at a time can lead to packets being dropped by the
 125  * network adapter, forcing superfluous retries and possibly timeouts.
 126  * Thus, we set our budget to greater than 1.
 127  */
 128 static int poll_one_napi(struct netpoll_info *npinfo,
 129                          struct napi_struct *napi, int budget)
 130 {
 131         int work;
 132
 133         /* net_rx_action's ->poll() invocations and our's are
 134          * synchronized by this test which is only made while
 135          * holding the napi->poll_lock.
 136          */
 137         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 138                 return budget;
 139
 140         npinfo->rx_flags |= NETPOLL_RX_DROP;
 141         atomic_inc(&trapped);
 142         set_bit(NAPI_STATE_NPSVC, &napi->state);
 143
 144         work = napi->poll(napi, budget);
 145         trace_napi_poll(napi);
 146
 147         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 148         atomic_dec(&trapped);
 149         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 150
 151         return budget - work;
 152 }
 153
 154 static void poll_napi(struct net_device *dev)
 155 {
 156         struct napi_struct *napi;
 157         int budget = 16;
 158
 159         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 160                 if (napi->poll_owner != smp_processor_id() &&
 161                     spin_trylock(&napi->poll_lock)) {
 162                         budget = poll_one_napi(dev->npinfo, napi, budget);
 163                         spin_unlock(&napi->poll_lock);
 164
 165                         if (!budget)
 166                                 break;
 167                 }
 168         }
 169 }
 170
 171 static void service_arp_queue(struct netpoll_info *npi)
 172 {
 173         if (npi) {
 174                 struct sk_buff *skb;
 175
 176                 while ((skb = skb_dequeue(&npi->arp_tx)))
 177                         arp_reply(skb);
 178         }
 179 }
 180
 181 static void netpoll_poll_dev(struct net_device *dev)
 182 {
 183         const struct net_device_ops *ops;
 184
 185         if (!dev || !netif_running(dev))
 186                 return;
 187
 188         ops = dev->netdev_ops;
 189         if (!ops->ndo_poll_controller)
 190                 return;
 191
 192         /* Process pending work on NIC */
 193         ops->ndo_poll_controller(dev);
 194
 195         poll_napi(dev);
 196
 197         if (dev->priv_flags & IFF_SLAVE) {
 198                 if (dev->npinfo) {
 199                         struct net_device *bond_dev = dev->master;
 200                         struct sk_buff *skb;
 201                         while ((skb = skb_dequeue(&dev->npinfo->arp_tx))) {
 202                                 skb->dev = bond_dev;
 203                                 skb_queue_tail(&bond_dev->npinfo->arp_tx, skb);
 204                         }
 205                 }
 206         }
 207
 208         service_arp_queue(dev->npinfo);
 209
 210         zap_completion_queue();
 211 }
 212
 213 static void refill_skbs(void)
 214 {
 215         struct sk_buff *skb;
 216         unsigned long flags;
 217
 218         spin_lock_irqsave(&skb_pool.lock, flags);
 219         while (skb_pool.qlen < MAX_SKBS) {
 220                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 221                 if (!skb)
 222                         break;
 223
 224                 __skb_queue_tail(&skb_pool, skb);
 225         }
 226         spin_unlock_irqrestore(&skb_pool.lock, flags);
 227 }
 228
 229 static void zap_completion_queue(void)
 230 {
 231         unsigned long flags;
 232         struct softnet_data *sd = &get_cpu_var(softnet_data);
 233
 234         if (sd->completion_queue) {
 235                 struct sk_buff *clist;
 236
 237                 local_irq_save(flags);
 238                 clist = sd->completion_queue;
 239                 sd->completion_queue = NULL;
 240                 local_irq_restore(flags);
 241
 242                 while (clist != NULL) {
 243                         struct sk_buff *skb = clist;
 244                         clist = clist->next;
 245                         if (skb->destructor) {
 246                                 atomic_inc(&skb->users);
 247                                 dev_kfree_skb_any(skb); /* put this one back */
 248                         } else {
 249                                 __kfree_skb(skb);
 250                         }
 251                 }
 252         }
 253
 254         put_cpu_var(softnet_data);
 255 }
 256
 257 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 258 {
 259         int count = 0;
 260         struct sk_buff *skb;
 261
 262         zap_completion_queue();
 263         refill_skbs();
 264 repeat:
 265
 266         skb = alloc_skb(len, GFP_ATOMIC);
 267         if (!skb)
 268                 skb = skb_dequeue(&skb_pool);
 269
 270         if (!skb) {
 271                 if (++count < 10) {
 272                         netpoll_poll_dev(np->dev);
 273                         goto repeat;
 274                 }
 275                 return NULL;
 276         }
 277
 278         atomic_set(&skb->users, 1);
 279         skb_reserve(skb, reserve);
 280         return skb;
 281 }
 282
 283 static int netpoll_owner_active(struct net_device *dev)
 284 {
 285         struct napi_struct *napi;
 286
 287         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 288                 if (napi->poll_owner == smp_processor_id())
 289                         return 1;
 290         }
 291         return 0;
 292 }
 293
 294 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 295                              struct net_device *dev)
 296 {
 297         int status = NETDEV_TX_BUSY;
 298         unsigned long tries;
 299         const struct net_device_ops *ops = dev->netdev_ops;
 300         /* It is up to the caller to keep npinfo alive. */
 301         struct netpoll_info *npinfo = np->dev->npinfo;
 302
 303         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 304                 __kfree_skb(skb);
 305                 return;
 306         }
 307
 308         /* don't get messages out of order, and no recursion */
 309         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 310                 struct netdev_queue *txq;
 311                 unsigned long flags;
 312
 313                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 314
 315                 local_irq_save(flags);
 316                 /* try until next clock tick */
 317                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 318                      tries > 0; --tries) {
 319                         if (__netif_tx_trylock(txq)) {
 320                                 if (!netif_tx_queue_stopped(txq)) {
 321                                         status = ops->ndo_start_xmit(skb, dev);
 322                                         if (status == NETDEV_TX_OK)
 323                                                 txq_trans_update(txq);
 324                                 }
 325                                 __netif_tx_unlock(txq);
 326
 327                                 if (status == NETDEV_TX_OK)
 328                                         break;
 329
 330                         }
 331
 332                         /* tickle device maybe there is some cleanup */
 333                         netpoll_poll_dev(np->dev);
 334
 335                         udelay(USEC_PER_POLL);
 336                 }
 337
 338                 WARN_ONCE(!irqs_disabled(),
 339                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 340                         dev->name, ops->ndo_start_xmit);
 341
 342                 local_irq_restore(flags);
 343         }
 344
 345         if (status != NETDEV_TX_OK) {
 346                 skb_queue_tail(&npinfo->txq, skb);
 347                 schedule_delayed_work(&npinfo->tx_work,0);
 348         }
 349 }
 350 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 351
 352 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 353 {
 354         int total_len, eth_len, ip_len, udp_len;
 355         struct sk_buff *skb;
 356         struct udphdr *udph;
 357         struct iphdr *iph;
 358         struct ethhdr *eth;
 359
 360         udp_len = len + sizeof(*udph);
 361         ip_len = eth_len = udp_len + sizeof(*iph);
 362         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 363
 364         skb = find_skb(np, total_len, total_len - len);
 365         if (!skb)
 366                 return;
 367
 368         skb_copy_to_linear_data(skb, msg, len);
 369         skb->len += len;
 370
 371         skb_push(skb, sizeof(*udph));
 372         skb_reset_transport_header(skb);
 373         udph = udp_hdr(skb);
 374         udph->source = htons(np->local_port);
 375         udph->dest = htons(np->remote_port);
 376         udph->len = htons(udp_len);
 377         udph->check = 0;
 378         udph->check = csum_tcpudp_magic(np->local_ip,
 379                                         np->remote_ip,
 380                                         udp_len, IPPROTO_UDP,
 381                                         csum_partial(udph, udp_len, 0));
 382         if (udph->check == 0)
 383                 udph->check = CSUM_MANGLED_0;
 384
 385         skb_push(skb, sizeof(*iph));
 386         skb_reset_network_header(skb);
 387         iph = ip_hdr(skb);
 388
 389         /* iph->version = 4; iph->ihl = 5; */
 390         put_unaligned(0x45, (unsigned char *)iph);
 391         iph->tos      = 0;
 392         put_unaligned(htons(ip_len), &(iph->tot_len));
 393         iph->id       = 0;
 394         iph->frag_off = 0;
 395         iph->ttl      = 64;
 396         iph->protocol = IPPROTO_UDP;
 397         iph->check    = 0;
 398         put_unaligned(np->local_ip, &(iph->saddr));
 399         put_unaligned(np->remote_ip, &(iph->daddr));
 400         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 401
 402         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 403         skb_reset_mac_header(skb);
 404         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 405         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 406         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 407
 408         skb->dev = np->dev;
 409
 410         netpoll_send_skb(np, skb);
 411 }
 412 EXPORT_SYMBOL(netpoll_send_udp);
 413
 414 static void arp_reply(struct sk_buff *skb)
 415 {
 416         struct netpoll_info *npinfo = skb->dev->npinfo;
 417         struct arphdr *arp;
 418         unsigned char *arp_ptr;
 419         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 420         __be32 sip, tip;
 421         unsigned char *sha;
 422         struct sk_buff *send_skb;
 423         struct netpoll *np, *tmp;
 424         unsigned long flags;
 425         int hits = 0;
 426
 427         if (list_empty(&npinfo->rx_np))
 428                 return;
 429
 430         /* Before checking the packet, we do some early
 431            inspection whether this is interesting at all */
 432         spin_lock_irqsave(&npinfo->rx_lock, flags);
 433         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 434                 if (np->dev == skb->dev)
 435                         hits++;
 436         }
 437         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 438
 439         /* No netpoll struct is using this dev */
 440         if (!hits)
 441                 return;
 442
 443         /* No arp on this interface */
 444         if (skb->dev->flags & IFF_NOARP)
 445                 return;
 446
 447         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 448                 return;
 449
 450         skb_reset_network_header(skb);
 451         skb_reset_transport_header(skb);
 452         arp = arp_hdr(skb);
 453
 454         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 455              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 456             arp->ar_pro != htons(ETH_P_IP) ||
 457             arp->ar_op != htons(ARPOP_REQUEST))
 458                 return;
 459
 460         arp_ptr = (unsigned char *)(arp+1);
 461         /* save the location of the src hw addr */
 462         sha = arp_ptr;
 463         arp_ptr += skb->dev->addr_len;
 464         memcpy(&sip, arp_ptr, 4);
 465         arp_ptr += 4;
 466         /* If we actually cared about dst hw addr,
 467            it would get copied here */
 468         arp_ptr += skb->dev->addr_len;
 469         memcpy(&tip, arp_ptr, 4);
 470
 471         /* Should we ignore arp? */
 472         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 473                 return;
 474
 475         size = arp_hdr_len(skb->dev);
 476
 477         spin_lock_irqsave(&npinfo->rx_lock, flags);
 478         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 479                 if (tip != np->local_ip)
 480                         continue;
 481
 482                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 483                                     LL_RESERVED_SPACE(np->dev));
 484                 if (!send_skb)
 485                         continue;
 486
 487                 skb_reset_network_header(send_skb);
 488                 arp = (struct arphdr *) skb_put(send_skb, size);
 489                 send_skb->dev = skb->dev;
 490                 send_skb->protocol = htons(ETH_P_ARP);
 491
 492                 /* Fill the device header for the ARP frame */
 493                 if (dev_hard_header(send_skb, skb->dev, ptype,
 494                                     sha, np->dev->dev_addr,
 495                                     send_skb->len) < 0) {
 496                         kfree_skb(send_skb);
 497                         continue;
 498                 }
 499
 500                 /*
 501                  * Fill out the arp protocol part.
 502                  *
 503                  * we only support ethernet device type,
 504                  * which (according to RFC 1390) should
 505                  * always equal 1 (Ethernet).
 506                  */
 507
 508                 arp->ar_hrd = htons(np->dev->type);
 509                 arp->ar_pro = htons(ETH_P_IP);
 510                 arp->ar_hln = np->dev->addr_len;
 511                 arp->ar_pln = 4;
 512                 arp->ar_op = htons(type);
 513
 514                 arp_ptr = (unsigned char *)(arp + 1);
 515                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 516                 arp_ptr += np->dev->addr_len;
 517                 memcpy(arp_ptr, &tip, 4);
 518                 arp_ptr += 4;
 519                 memcpy(arp_ptr, sha, np->dev->addr_len);
 520                 arp_ptr += np->dev->addr_len;
 521                 memcpy(arp_ptr, &sip, 4);
 522
 523                 netpoll_send_skb(np, send_skb);
 524
 525                 /* If there are several rx_hooks for the same address,
 526                    we're fine by sending a single reply */
 527                 break;
 528         }
 529         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 530 }
 531
 532 int __netpoll_rx(struct sk_buff *skb)
 533 {
 534         int proto, len, ulen;
 535         int hits = 0;
 536         const struct iphdr *iph;
 537         struct udphdr *uh;
 538         struct netpoll_info *npinfo = skb->dev->npinfo;
 539         struct netpoll *np, *tmp;
 540
 541         if (list_empty(&npinfo->rx_np))
 542                 goto out;
 543
 544         if (skb->dev->type != ARPHRD_ETHER)
 545                 goto out;
 546
 547         /* check if netpoll clients need ARP */
 548         if (skb->protocol == htons(ETH_P_ARP) &&
 549             atomic_read(&trapped)) {
 550                 skb_queue_tail(&npinfo->arp_tx, skb);
 551                 return 1;
 552         }
 553
 554         proto = ntohs(eth_hdr(skb)->h_proto);
 555         if (proto != ETH_P_IP)
 556                 goto out;
 557         if (skb->pkt_type == PACKET_OTHERHOST)
 558                 goto out;
 559         if (skb_shared(skb))
 560                 goto out;
 561
 562         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 563                 goto out;
 564         iph = (struct iphdr *)skb->data;
 565         if (iph->ihl < 5 || iph->version != 4)
 566                 goto out;
 567         if (!pskb_may_pull(skb, iph->ihl*4))
 568                 goto out;
 569         iph = (struct iphdr *)skb->data;
 570         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 571                 goto out;
 572
 573         len = ntohs(iph->tot_len);
 574         if (skb->len < len || len < iph->ihl*4)
 575                 goto out;
 576
 577         /*
 578          * Our transport medium may have padded the buffer out.
 579          * Now We trim to the true length of the frame.
 580          */
 581         if (pskb_trim_rcsum(skb, len))
 582                 goto out;
 583
 584         iph = (struct iphdr *)skb->data;
 585         if (iph->protocol != IPPROTO_UDP)
 586                 goto out;
 587
 588         len -= iph->ihl*4;
 589         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 590         ulen = ntohs(uh->len);
 591
 592         if (ulen != len)
 593                 goto out;
 594         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 595                 goto out;
 596
 597         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 598                 if (np->local_ip && np->local_ip != iph->daddr)
 599                         continue;
 600                 if (np->remote_ip && np->remote_ip != iph->saddr)
 601                         continue;
 602                 if (np->local_port && np->local_port != ntohs(uh->dest))
 603                         continue;
 604
 605                 np->rx_hook(np, ntohs(uh->source),
 606                                (char *)(uh+1),
 607                                ulen - sizeof(struct udphdr));
 608                 hits++;
 609         }
 610
 611         if (!hits)
 612                 goto out;
 613
 614         kfree_skb(skb);
 615         return 1;
 616
 617 out:
 618         if (atomic_read(&trapped)) {
 619                 kfree_skb(skb);
 620                 return 1;
 621         }
 622
 623         return 0;
 624 }
 625
 626 void netpoll_print_options(struct netpoll *np)
 627 {
 628         printk(KERN_INFO "%s: local port %d\n",
 629                          np->name, np->local_port);
 630         printk(KERN_INFO "%s: local IP %pI4\n",
 631                          np->name, &np->local_ip);
 632         printk(KERN_INFO "%s: interface '%s'\n",
 633                          np->name, np->dev_name);
 634         printk(KERN_INFO "%s: remote port %d\n",
 635                          np->name, np->remote_port);
 636         printk(KERN_INFO "%s: remote IP %pI4\n",
 637                          np->name, &np->remote_ip);
 638         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 639                          np->name, np->remote_mac);
 640 }
 641 EXPORT_SYMBOL(netpoll_print_options);
 642
 643 int netpoll_parse_options(struct netpoll *np, char *opt)
 644 {
 645         char *cur=opt, *delim;
 646
 647         if (*cur != '@') {
 648                 if ((delim = strchr(cur, '@')) == NULL)
 649                         goto parse_failed;
 650                 *delim = 0;
 651                 np->local_port = simple_strtol(cur, NULL, 10);
 652                 cur = delim;
 653         }
 654         cur++;
 655
 656         if (*cur != '/') {
 657                 if ((delim = strchr(cur, '/')) == NULL)
 658                         goto parse_failed;
 659                 *delim = 0;
 660                 np->local_ip = in_aton(cur);
 661                 cur = delim;
 662         }
 663         cur++;
 664
 665         if (*cur != ',') {
 666                 /* parse out dev name */
 667                 if ((delim = strchr(cur, ',')) == NULL)
 668                         goto parse_failed;
 669                 *delim = 0;
 670                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 671                 cur = delim;
 672         }
 673         cur++;
 674
 675         if (*cur != '@') {
 676                 /* dst port */
 677                 if ((delim = strchr(cur, '@')) == NULL)
 678                         goto parse_failed;
 679                 *delim = 0;
 680                 if (*cur == ' ' || *cur == '\t')
 681                         printk(KERN_INFO "%s: warning: whitespace"
 682                                         "is not allowed\n", np->name);
 683                 np->remote_port = simple_strtol(cur, NULL, 10);
 684                 cur = delim;
 685         }
 686         cur++;
 687
 688         /* dst ip */
 689         if ((delim = strchr(cur, '/')) == NULL)
 690                 goto parse_failed;
 691         *delim = 0;
 692         np->remote_ip = in_aton(cur);
 693         cur = delim + 1;
 694
 695         if (*cur != 0) {
 696                 /* MAC address */
 697                 if (!mac_pton(cur, np->remote_mac))
 698                         goto parse_failed;
 699         }
 700
 701         netpoll_print_options(np);
 702
 703         return 0;
 704
 705  parse_failed:
 706         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 707                np->name, cur);
 708         return -1;
 709 }
 710 EXPORT_SYMBOL(netpoll_parse_options);
 711
 712 int __netpoll_setup(struct netpoll *np)
 713 {
 714         struct net_device *ndev = np->dev;
 715         struct netpoll_info *npinfo;
 716         const struct net_device_ops *ops;
 717         unsigned long flags;
 718         int err;
 719
 720         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 721             !ndev->netdev_ops->ndo_poll_controller) {
 722                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 723                        np->name, np->dev_name);
 724                 err = -ENOTSUPP;
 725                 goto out;
 726         }
 727
 728         if (!ndev->npinfo) {
 729                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 730                 if (!npinfo) {
 731                         err = -ENOMEM;
 732                         goto out;
 733                 }
 734
 735                 npinfo->rx_flags = 0;
 736                 INIT_LIST_HEAD(&npinfo->rx_np);
 737
 738                 spin_lock_init(&npinfo->rx_lock);
 739                 skb_queue_head_init(&npinfo->arp_tx);
 740                 skb_queue_head_init(&npinfo->txq);
 741                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 742
 743                 atomic_set(&npinfo->refcnt, 1);
 744
 745                 ops = np->dev->netdev_ops;
 746                 if (ops->ndo_netpoll_setup) {
 747                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 748                         if (err)
 749                                 goto free_npinfo;
 750                 }
 751         } else {
 752                 npinfo = ndev->npinfo;
 753                 atomic_inc(&npinfo->refcnt);
 754         }
 755
 756         npinfo->netpoll = np;
 757
 758         if (np->rx_hook) {
 759                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 760                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 761                 list_add_tail(&np->rx, &npinfo->rx_np);
 762                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 763         }
 764
 765         /* last thing to do is link it to the net device structure */
 766         RCU_INIT_POINTER(ndev->npinfo, npinfo);
 767
 768         return 0;
 769
 770 free_npinfo:
 771         kfree(npinfo);
 772 out:
 773         return err;
 774 }
 775 EXPORT_SYMBOL_GPL(__netpoll_setup);
 776
 777 int netpoll_setup(struct netpoll *np)
 778 {
 779         struct net_device *ndev = NULL;
 780         struct in_device *in_dev;
 781         int err;
 782
 783         if (np->dev_name)
 784                 ndev = dev_get_by_name(&init_net, np->dev_name);
 785         if (!ndev) {
 786                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 787                        np->name, np->dev_name);
 788                 return -ENODEV;
 789         }
 790
 791         if (ndev->master) {
 792                 printk(KERN_ERR "%s: %s is a slave device, aborting.\n",
 793                        np->name, np->dev_name);
 794                 err = -EBUSY;
 795                 goto put;
 796         }
 797
 798         if (!netif_running(ndev)) {
 799                 unsigned long atmost, atleast;
 800
 801                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 802                        np->name, np->dev_name);
 803
 804                 rtnl_lock();
 805                 err = dev_open(ndev);
 806                 rtnl_unlock();
 807
 808                 if (err) {
 809                         printk(KERN_ERR "%s: failed to open %s\n",
 810                                np->name, ndev->name);
 811                         goto put;
 812                 }
 813
 814                 atleast = jiffies + HZ/10;
 815                 atmost = jiffies + carrier_timeout * HZ;
 816                 while (!netif_carrier_ok(ndev)) {
 817                         if (time_after(jiffies, atmost)) {
 818                                 printk(KERN_NOTICE
 819                                        "%s: timeout waiting for carrier\n",
 820                                        np->name);
 821                                 break;
 822                         }
 823                         msleep(1);
 824                 }
 825
 826                 /* If carrier appears to come up instantly, we don't
 827                  * trust it and pause so that we don't pump all our
 828                  * queued console messages into the bitbucket.
 829                  */
 830
 831                 if (time_before(jiffies, atleast)) {
 832                         printk(KERN_NOTICE "%s: carrier detect appears"
 833                                " untrustworthy, waiting 4 seconds\n",
 834                                np->name);
 835                         msleep(4000);
 836                 }
 837         }
 838
 839         if (!np->local_ip) {
 840                 rcu_read_lock();
 841                 in_dev = __in_dev_get_rcu(ndev);
 842
 843                 if (!in_dev || !in_dev->ifa_list) {
 844                         rcu_read_unlock();
 845                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 846                                np->name, np->dev_name);
 847                         err = -EDESTADDRREQ;
 848                         goto put;
 849                 }
 850
 851                 np->local_ip = in_dev->ifa_list->ifa_local;
 852                 rcu_read_unlock();
 853                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 854         }
 855
 856         np->dev = ndev;
 857
 858         /* fill up the skb queue */
 859         refill_skbs();
 860
 861         rtnl_lock();
 862         err = __netpoll_setup(np);
 863         rtnl_unlock();
 864
 865         if (err)
 866                 goto put;
 867
 868         return 0;
 869
 870 put:
 871         dev_put(ndev);
 872         return err;
 873 }
 874 EXPORT_SYMBOL(netpoll_setup);
 875
 876 static int __init netpoll_init(void)
 877 {
 878         skb_queue_head_init(&skb_pool);
 879         return 0;
 880 }
 881 core_initcall(netpoll_init);
 882
 883 void __netpoll_cleanup(struct netpoll *np)
 884 {
 885         struct netpoll_info *npinfo;
 886         unsigned long flags;
 887
 888         npinfo = np->dev->npinfo;
 889         if (!npinfo)
 890                 return;
 891
 892         if (!list_empty(&npinfo->rx_np)) {
 893                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 894                 list_del(&np->rx);
 895                 if (list_empty(&npinfo->rx_np))
 896                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 897                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 898         }
 899
 900         if (atomic_dec_and_test(&npinfo->refcnt)) {
 901                 const struct net_device_ops *ops;
 902
 903                 ops = np->dev->netdev_ops;
 904                 if (ops->ndo_netpoll_cleanup)
 905                         ops->ndo_netpoll_cleanup(np->dev);
 906
 907                 RCU_INIT_POINTER(np->dev->npinfo, NULL);
 908
 909                 /* avoid racing with NAPI reading npinfo */
 910                 synchronize_rcu_bh();
 911
 912                 skb_queue_purge(&npinfo->arp_tx);
 913                 skb_queue_purge(&npinfo->txq);
 914                 cancel_delayed_work_sync(&npinfo->tx_work);
 915
 916                 /* clean after last, unfinished work */
 917                 __skb_queue_purge(&npinfo->txq);
 918                 kfree(npinfo);
 919         }
 920 }
 921 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 922
 923 void netpoll_cleanup(struct netpoll *np)
 924 {
 925         if (!np->dev)
 926                 return;
 927
 928         rtnl_lock();
 929         __netpoll_cleanup(np);
 930         rtnl_unlock();
 931
 932         dev_put(np->dev);
 933         np->dev = NULL;
 934 }
 935 EXPORT_SYMBOL(netpoll_cleanup);
 936
 937 int netpoll_trap(void)
 938 {
 939         return atomic_read(&trapped);
 940 }
 941 EXPORT_SYMBOL(netpoll_trap);
 942
 943 void netpoll_set_trap(int trap)
 944 {
 945         if (trap)
 946                 atomic_inc(&trapped);
 947         else
 948                 atomic_dec(&trapped);
 949 }
 950 EXPORT_SYMBOL(netpoll_set_trap);