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 <net/tcp.h>
  27 #include <net/udp.h>
  28 #include <asm/unaligned.h>
  29 #include <trace/events/napi.h>
  30
  31 /*
  32  * We maintain a small pool of fully-sized skbs, to make sure the
  33  * message gets out even in extreme OOM situations.
  34  */
  35
  36 #define MAX_UDP_CHUNK 1460
  37 #define MAX_SKBS 32
  38 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  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_stopped(txq) ||
  80                     netif_tx_queue_frozen(txq) ||
  81                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  82                         skb_queue_head(&npinfo->txq, skb);
  83                         __netif_tx_unlock(txq);
  84                         local_irq_restore(flags);
  85
  86                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  87                         return;
  88                 }
  89                 __netif_tx_unlock(txq);
  90                 local_irq_restore(flags);
  91         }
  92 }
  93
  94 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  95                             unsigned short ulen, __be32 saddr, __be32 daddr)
  96 {
  97         __wsum psum;
  98
  99         if (uh->check == 0 || skb_csum_unnecessary(skb))
 100                 return 0;
 101
 102         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 103
 104         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 105             !csum_fold(csum_add(psum, skb->csum)))
 106                 return 0;
 107
 108         skb->csum = psum;
 109
 110         return __skb_checksum_complete(skb);
 111 }
 112
 113 /*
 114  * Check whether delayed processing was scheduled for our NIC. If so,
 115  * we attempt to grab the poll lock and use ->poll() to pump the card.
 116  * If this fails, either we've recursed in ->poll() or it's already
 117  * running on another CPU.
 118  *
 119  * Note: we don't mask interrupts with this lock because we're using
 120  * trylock here and interrupts are already disabled in the softirq
 121  * case. Further, we test the poll_owner to avoid recursion on UP
 122  * systems where the lock doesn't exist.
 123  *
 124  * In cases where there is bi-directional communications, reading only
 125  * one message at a time can lead to packets being dropped by the
 126  * network adapter, forcing superfluous retries and possibly timeouts.
 127  * Thus, we set our budget to greater than 1.
 128  */
 129 static int poll_one_napi(struct netpoll_info *npinfo,
 130                          struct napi_struct *napi, int budget)
 131 {
 132         int work;
 133
 134         /* net_rx_action's ->poll() invocations and our's are
 135          * synchronized by this test which is only made while
 136          * holding the napi->poll_lock.
 137          */
 138         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 139                 return budget;
 140
 141         npinfo->rx_flags |= NETPOLL_RX_DROP;
 142         atomic_inc(&trapped);
 143         set_bit(NAPI_STATE_NPSVC, &napi->state);
 144
 145         work = napi->poll(napi, budget);
 146         trace_napi_poll(napi);
 147
 148         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 149         atomic_dec(&trapped);
 150         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 151
 152         return budget - work;
 153 }
 154
 155 static void poll_napi(struct net_device *dev)
 156 {
 157         struct napi_struct *napi;
 158         int budget = 16;
 159
 160         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 161                 if (napi->poll_owner != smp_processor_id() &&
 162                     spin_trylock(&napi->poll_lock)) {
 163                         budget = poll_one_napi(dev->npinfo, napi, budget);
 164                         spin_unlock(&napi->poll_lock);
 165
 166                         if (!budget)
 167                                 break;
 168                 }
 169         }
 170 }
 171
 172 static void service_arp_queue(struct netpoll_info *npi)
 173 {
 174         if (npi) {
 175                 struct sk_buff *skb;
 176
 177                 while ((skb = skb_dequeue(&npi->arp_tx)))
 178                         arp_reply(skb);
 179         }
 180 }
 181
 182 void netpoll_poll_dev(struct net_device *dev)
 183 {
 184         const struct net_device_ops *ops;
 185
 186         if (!dev || !netif_running(dev))
 187                 return;
 188
 189         ops = dev->netdev_ops;
 190         if (!ops->ndo_poll_controller)
 191                 return;
 192
 193         /* Process pending work on NIC */
 194         ops->ndo_poll_controller(dev);
 195
 196         poll_napi(dev);
 197
 198         service_arp_queue(dev->npinfo);
 199
 200         zap_completion_queue();
 201 }
 202
 203 void netpoll_poll(struct netpoll *np)
 204 {
 205         netpoll_poll_dev(np->dev);
 206 }
 207
 208 static void refill_skbs(void)
 209 {
 210         struct sk_buff *skb;
 211         unsigned long flags;
 212
 213         spin_lock_irqsave(&skb_pool.lock, flags);
 214         while (skb_pool.qlen < MAX_SKBS) {
 215                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 216                 if (!skb)
 217                         break;
 218
 219                 __skb_queue_tail(&skb_pool, skb);
 220         }
 221         spin_unlock_irqrestore(&skb_pool.lock, flags);
 222 }
 223
 224 static void zap_completion_queue(void)
 225 {
 226         unsigned long flags;
 227         struct softnet_data *sd = &get_cpu_var(softnet_data);
 228
 229         if (sd->completion_queue) {
 230                 struct sk_buff *clist;
 231
 232                 local_irq_save(flags);
 233                 clist = sd->completion_queue;
 234                 sd->completion_queue = NULL;
 235                 local_irq_restore(flags);
 236
 237                 while (clist != NULL) {
 238                         struct sk_buff *skb = clist;
 239                         clist = clist->next;
 240                         if (skb->destructor) {
 241                                 atomic_inc(&skb->users);
 242                                 dev_kfree_skb_any(skb); /* put this one back */
 243                         } else {
 244                                 __kfree_skb(skb);
 245                         }
 246                 }
 247         }
 248
 249         put_cpu_var(softnet_data);
 250 }
 251
 252 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 253 {
 254         int count = 0;
 255         struct sk_buff *skb;
 256
 257         zap_completion_queue();
 258         refill_skbs();
 259 repeat:
 260
 261         skb = alloc_skb(len, GFP_ATOMIC);
 262         if (!skb)
 263                 skb = skb_dequeue(&skb_pool);
 264
 265         if (!skb) {
 266                 if (++count < 10) {
 267                         netpoll_poll(np);
 268                         goto repeat;
 269                 }
 270                 return NULL;
 271         }
 272
 273         atomic_set(&skb->users, 1);
 274         skb_reserve(skb, reserve);
 275         return skb;
 276 }
 277
 278 static int netpoll_owner_active(struct net_device *dev)
 279 {
 280         struct napi_struct *napi;
 281
 282         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 283                 if (napi->poll_owner == smp_processor_id())
 284                         return 1;
 285         }
 286         return 0;
 287 }
 288
 289 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 290 {
 291         int status = NETDEV_TX_BUSY;
 292         unsigned long tries;
 293         struct net_device *dev = np->dev;
 294         const struct net_device_ops *ops = dev->netdev_ops;
 295         struct netpoll_info *npinfo = np->dev->npinfo;
 296
 297         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 298                 __kfree_skb(skb);
 299                 return;
 300         }
 301
 302         /* don't get messages out of order, and no recursion */
 303         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 304                 struct netdev_queue *txq;
 305                 unsigned long flags;
 306
 307                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 308
 309                 local_irq_save(flags);
 310                 /* try until next clock tick */
 311                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 312                      tries > 0; --tries) {
 313                         if (__netif_tx_trylock(txq)) {
 314                                 if (!netif_tx_queue_stopped(txq)) {
 315                                         dev->priv_flags |= IFF_IN_NETPOLL;
 316                                         status = ops->ndo_start_xmit(skb, dev);
 317                                         dev->priv_flags &= ~IFF_IN_NETPOLL;
 318                                         if (status == NETDEV_TX_OK)
 319                                                 txq_trans_update(txq);
 320                                 }
 321                                 __netif_tx_unlock(txq);
 322
 323                                 if (status == NETDEV_TX_OK)
 324                                         break;
 325
 326                         }
 327
 328                         /* tickle device maybe there is some cleanup */
 329                         netpoll_poll(np);
 330
 331                         udelay(USEC_PER_POLL);
 332                 }
 333
 334                 WARN_ONCE(!irqs_disabled(),
 335                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 336                         dev->name, ops->ndo_start_xmit);
 337
 338                 local_irq_restore(flags);
 339         }
 340
 341         if (status != NETDEV_TX_OK) {
 342                 skb_queue_tail(&npinfo->txq, skb);
 343                 schedule_delayed_work(&npinfo->tx_work,0);
 344         }
 345 }
 346
 347 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 348 {
 349         int total_len, eth_len, ip_len, udp_len;
 350         struct sk_buff *skb;
 351         struct udphdr *udph;
 352         struct iphdr *iph;
 353         struct ethhdr *eth;
 354
 355         udp_len = len + sizeof(*udph);
 356         ip_len = eth_len = udp_len + sizeof(*iph);
 357         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 358
 359         skb = find_skb(np, total_len, total_len - len);
 360         if (!skb)
 361                 return;
 362
 363         skb_copy_to_linear_data(skb, msg, len);
 364         skb->len += len;
 365
 366         skb_push(skb, sizeof(*udph));
 367         skb_reset_transport_header(skb);
 368         udph = udp_hdr(skb);
 369         udph->source = htons(np->local_port);
 370         udph->dest = htons(np->remote_port);
 371         udph->len = htons(udp_len);
 372         udph->check = 0;
 373         udph->check = csum_tcpudp_magic(np->local_ip,
 374                                         np->remote_ip,
 375                                         udp_len, IPPROTO_UDP,
 376                                         csum_partial(udph, udp_len, 0));
 377         if (udph->check == 0)
 378                 udph->check = CSUM_MANGLED_0;
 379
 380         skb_push(skb, sizeof(*iph));
 381         skb_reset_network_header(skb);
 382         iph = ip_hdr(skb);
 383
 384         /* iph->version = 4; iph->ihl = 5; */
 385         put_unaligned(0x45, (unsigned char *)iph);
 386         iph->tos      = 0;
 387         put_unaligned(htons(ip_len), &(iph->tot_len));
 388         iph->id       = 0;
 389         iph->frag_off = 0;
 390         iph->ttl      = 64;
 391         iph->protocol = IPPROTO_UDP;
 392         iph->check    = 0;
 393         put_unaligned(np->local_ip, &(iph->saddr));
 394         put_unaligned(np->remote_ip, &(iph->daddr));
 395         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 396
 397         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 398         skb_reset_mac_header(skb);
 399         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 400         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 401         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 402
 403         skb->dev = np->dev;
 404
 405         netpoll_send_skb(np, skb);
 406 }
 407
 408 static void arp_reply(struct sk_buff *skb)
 409 {
 410         struct netpoll_info *npinfo = skb->dev->npinfo;
 411         struct arphdr *arp;
 412         unsigned char *arp_ptr;
 413         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 414         __be32 sip, tip;
 415         unsigned char *sha;
 416         struct sk_buff *send_skb;
 417         struct netpoll *np, *tmp;
 418         unsigned long flags;
 419         int hits = 0;
 420
 421         if (list_empty(&npinfo->rx_np))
 422                 return;
 423
 424         /* Before checking the packet, we do some early
 425            inspection whether this is interesting at all */
 426         spin_lock_irqsave(&npinfo->rx_lock, flags);
 427         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 428                 if (np->dev == skb->dev)
 429                         hits++;
 430         }
 431         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 432
 433         /* No netpoll struct is using this dev */
 434         if (!hits)
 435                 return;
 436
 437         /* No arp on this interface */
 438         if (skb->dev->flags & IFF_NOARP)
 439                 return;
 440
 441         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 442                 return;
 443
 444         skb_reset_network_header(skb);
 445         skb_reset_transport_header(skb);
 446         arp = arp_hdr(skb);
 447
 448         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 449              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 450             arp->ar_pro != htons(ETH_P_IP) ||
 451             arp->ar_op != htons(ARPOP_REQUEST))
 452                 return;
 453
 454         arp_ptr = (unsigned char *)(arp+1);
 455         /* save the location of the src hw addr */
 456         sha = arp_ptr;
 457         arp_ptr += skb->dev->addr_len;
 458         memcpy(&sip, arp_ptr, 4);
 459         arp_ptr += 4;
 460         /* If we actually cared about dst hw addr,
 461            it would get copied here */
 462         arp_ptr += skb->dev->addr_len;
 463         memcpy(&tip, arp_ptr, 4);
 464
 465         /* Should we ignore arp? */
 466         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 467                 return;
 468
 469         size = arp_hdr_len(skb->dev);
 470
 471         spin_lock_irqsave(&npinfo->rx_lock, flags);
 472         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 473                 if (tip != np->local_ip)
 474                         continue;
 475
 476                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 477                                     LL_RESERVED_SPACE(np->dev));
 478                 if (!send_skb)
 479                         continue;
 480
 481                 skb_reset_network_header(send_skb);
 482                 arp = (struct arphdr *) skb_put(send_skb, size);
 483                 send_skb->dev = skb->dev;
 484                 send_skb->protocol = htons(ETH_P_ARP);
 485
 486                 /* Fill the device header for the ARP frame */
 487                 if (dev_hard_header(send_skb, skb->dev, ptype,
 488                                     sha, np->dev->dev_addr,
 489                                     send_skb->len) < 0) {
 490                         kfree_skb(send_skb);
 491                         continue;
 492                 }
 493
 494                 /*
 495                  * Fill out the arp protocol part.
 496                  *
 497                  * we only support ethernet device type,
 498                  * which (according to RFC 1390) should
 499                  * always equal 1 (Ethernet).
 500                  */
 501
 502                 arp->ar_hrd = htons(np->dev->type);
 503                 arp->ar_pro = htons(ETH_P_IP);
 504                 arp->ar_hln = np->dev->addr_len;
 505                 arp->ar_pln = 4;
 506                 arp->ar_op = htons(type);
 507
 508                 arp_ptr = (unsigned char *)(arp + 1);
 509                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 510                 arp_ptr += np->dev->addr_len;
 511                 memcpy(arp_ptr, &tip, 4);
 512                 arp_ptr += 4;
 513                 memcpy(arp_ptr, sha, np->dev->addr_len);
 514                 arp_ptr += np->dev->addr_len;
 515                 memcpy(arp_ptr, &sip, 4);
 516
 517                 netpoll_send_skb(np, send_skb);
 518
 519                 /* If there are several rx_hooks for the same address,
 520                    we're fine by sending a single reply */
 521                 break;
 522         }
 523         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 524 }
 525
 526 int __netpoll_rx(struct sk_buff *skb)
 527 {
 528         int proto, len, ulen;
 529         int hits = 0;
 530         struct iphdr *iph;
 531         struct udphdr *uh;
 532         struct netpoll_info *npinfo = skb->dev->npinfo;
 533         struct netpoll *np, *tmp;
 534
 535         if (list_empty(&npinfo->rx_np))
 536                 goto out;
 537
 538         if (skb->dev->type != ARPHRD_ETHER)
 539                 goto out;
 540
 541         /* check if netpoll clients need ARP */
 542         if (skb->protocol == htons(ETH_P_ARP) &&
 543             atomic_read(&trapped)) {
 544                 skb_queue_tail(&npinfo->arp_tx, skb);
 545                 return 1;
 546         }
 547
 548         proto = ntohs(eth_hdr(skb)->h_proto);
 549         if (proto != ETH_P_IP)
 550                 goto out;
 551         if (skb->pkt_type == PACKET_OTHERHOST)
 552                 goto out;
 553         if (skb_shared(skb))
 554                 goto out;
 555
 556         iph = (struct iphdr *)skb->data;
 557         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 558                 goto out;
 559         if (iph->ihl < 5 || iph->version != 4)
 560                 goto out;
 561         if (!pskb_may_pull(skb, iph->ihl*4))
 562                 goto out;
 563         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 564                 goto out;
 565
 566         len = ntohs(iph->tot_len);
 567         if (skb->len < len || len < iph->ihl*4)
 568                 goto out;
 569
 570         /*
 571          * Our transport medium may have padded the buffer out.
 572          * Now We trim to the true length of the frame.
 573          */
 574         if (pskb_trim_rcsum(skb, len))
 575                 goto out;
 576
 577         if (iph->protocol != IPPROTO_UDP)
 578                 goto out;
 579
 580         len -= iph->ihl*4;
 581         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 582         ulen = ntohs(uh->len);
 583
 584         if (ulen != len)
 585                 goto out;
 586         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 587                 goto out;
 588
 589         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 590                 if (np->local_ip && np->local_ip != iph->daddr)
 591                         continue;
 592                 if (np->remote_ip && np->remote_ip != iph->saddr)
 593                         continue;
 594                 if (np->local_port && np->local_port != ntohs(uh->dest))
 595                         continue;
 596
 597                 np->rx_hook(np, ntohs(uh->source),
 598                                (char *)(uh+1),
 599                                ulen - sizeof(struct udphdr));
 600                 hits++;
 601         }
 602
 603         if (!hits)
 604                 goto out;
 605
 606         kfree_skb(skb);
 607         return 1;
 608
 609 out:
 610         if (atomic_read(&trapped)) {
 611                 kfree_skb(skb);
 612                 return 1;
 613         }
 614
 615         return 0;
 616 }
 617
 618 void netpoll_print_options(struct netpoll *np)
 619 {
 620         printk(KERN_INFO "%s: local port %d\n",
 621                          np->name, np->local_port);
 622         printk(KERN_INFO "%s: local IP %pI4\n",
 623                          np->name, &np->local_ip);
 624         printk(KERN_INFO "%s: interface '%s'\n",
 625                          np->name, np->dev_name);
 626         printk(KERN_INFO "%s: remote port %d\n",
 627                          np->name, np->remote_port);
 628         printk(KERN_INFO "%s: remote IP %pI4\n",
 629                          np->name, &np->remote_ip);
 630         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 631                          np->name, np->remote_mac);
 632 }
 633
 634 int netpoll_parse_options(struct netpoll *np, char *opt)
 635 {
 636         char *cur=opt, *delim;
 637
 638         if (*cur != '@') {
 639                 if ((delim = strchr(cur, '@')) == NULL)
 640                         goto parse_failed;
 641                 *delim = 0;
 642                 np->local_port = simple_strtol(cur, NULL, 10);
 643                 cur = delim;
 644         }
 645         cur++;
 646
 647         if (*cur != '/') {
 648                 if ((delim = strchr(cur, '/')) == NULL)
 649                         goto parse_failed;
 650                 *delim = 0;
 651                 np->local_ip = in_aton(cur);
 652                 cur = delim;
 653         }
 654         cur++;
 655
 656         if (*cur != ',') {
 657                 /* parse out dev name */
 658                 if ((delim = strchr(cur, ',')) == NULL)
 659                         goto parse_failed;
 660                 *delim = 0;
 661                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 662                 cur = delim;
 663         }
 664         cur++;
 665
 666         if (*cur != '@') {
 667                 /* dst port */
 668                 if ((delim = strchr(cur, '@')) == NULL)
 669                         goto parse_failed;
 670                 *delim = 0;
 671                 if (*cur == ' ' || *cur == '\t')
 672                         printk(KERN_INFO "%s: warning: whitespace"
 673                                         "is not allowed\n", np->name);
 674                 np->remote_port = simple_strtol(cur, NULL, 10);
 675                 cur = delim;
 676         }
 677         cur++;
 678
 679         /* dst ip */
 680         if ((delim = strchr(cur, '/')) == NULL)
 681                 goto parse_failed;
 682         *delim = 0;
 683         np->remote_ip = in_aton(cur);
 684         cur = delim + 1;
 685
 686         if (*cur != 0) {
 687                 /* MAC address */
 688                 if ((delim = strchr(cur, ':')) == NULL)
 689                         goto parse_failed;
 690                 *delim = 0;
 691                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 692                 cur = delim + 1;
 693                 if ((delim = strchr(cur, ':')) == NULL)
 694                         goto parse_failed;
 695                 *delim = 0;
 696                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 697                 cur = delim + 1;
 698                 if ((delim = strchr(cur, ':')) == NULL)
 699                         goto parse_failed;
 700                 *delim = 0;
 701                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 702                 cur = delim + 1;
 703                 if ((delim = strchr(cur, ':')) == NULL)
 704                         goto parse_failed;
 705                 *delim = 0;
 706                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 707                 cur = delim + 1;
 708                 if ((delim = strchr(cur, ':')) == NULL)
 709                         goto parse_failed;
 710                 *delim = 0;
 711                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 712                 cur = delim + 1;
 713                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 714         }
 715
 716         netpoll_print_options(np);
 717
 718         return 0;
 719
 720  parse_failed:
 721         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 722                np->name, cur);
 723         return -1;
 724 }
 725
 726 int netpoll_setup(struct netpoll *np)
 727 {
 728         struct net_device *ndev = NULL;
 729         struct in_device *in_dev;
 730         struct netpoll_info *npinfo;
 731         struct netpoll *npe, *tmp;
 732         unsigned long flags;
 733         int err;
 734
 735         if (np->dev_name)
 736                 ndev = dev_get_by_name(&init_net, np->dev_name);
 737         if (!ndev) {
 738                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 739                        np->name, np->dev_name);
 740                 return -ENODEV;
 741         }
 742
 743         np->dev = ndev;
 744         if (!ndev->npinfo) {
 745                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 746                 if (!npinfo) {
 747                         err = -ENOMEM;
 748                         goto put;
 749                 }
 750
 751                 npinfo->rx_flags = 0;
 752                 INIT_LIST_HEAD(&npinfo->rx_np);
 753
 754                 spin_lock_init(&npinfo->rx_lock);
 755                 skb_queue_head_init(&npinfo->arp_tx);
 756                 skb_queue_head_init(&npinfo->txq);
 757                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 758
 759                 atomic_set(&npinfo->refcnt, 1);
 760         } else {
 761                 npinfo = ndev->npinfo;
 762                 atomic_inc(&npinfo->refcnt);
 763         }
 764
 765         npinfo->netpoll = np;
 766
 767         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 768             !ndev->netdev_ops->ndo_poll_controller) {
 769                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 770                        np->name, np->dev_name);
 771                 err = -ENOTSUPP;
 772                 goto release;
 773         }
 774
 775         if (!netif_running(ndev)) {
 776                 unsigned long atmost, atleast;
 777
 778                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 779                        np->name, np->dev_name);
 780
 781                 rtnl_lock();
 782                 err = dev_open(ndev);
 783                 rtnl_unlock();
 784
 785                 if (err) {
 786                         printk(KERN_ERR "%s: failed to open %s\n",
 787                                np->name, ndev->name);
 788                         goto release;
 789                 }
 790
 791                 atleast = jiffies + HZ/10;
 792                 atmost = jiffies + carrier_timeout * HZ;
 793                 while (!netif_carrier_ok(ndev)) {
 794                         if (time_after(jiffies, atmost)) {
 795                                 printk(KERN_NOTICE
 796                                        "%s: timeout waiting for carrier\n",
 797                                        np->name);
 798                                 break;
 799                         }
 800                         msleep(1);
 801                 }
 802
 803                 /* If carrier appears to come up instantly, we don't
 804                  * trust it and pause so that we don't pump all our
 805                  * queued console messages into the bitbucket.
 806                  */
 807
 808                 if (time_before(jiffies, atleast)) {
 809                         printk(KERN_NOTICE "%s: carrier detect appears"
 810                                " untrustworthy, waiting 4 seconds\n",
 811                                np->name);
 812                         msleep(4000);
 813                 }
 814         }
 815
 816         if (!np->local_ip) {
 817                 rcu_read_lock();
 818                 in_dev = __in_dev_get_rcu(ndev);
 819
 820                 if (!in_dev || !in_dev->ifa_list) {
 821                         rcu_read_unlock();
 822                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 823                                np->name, np->dev_name);
 824                         err = -EDESTADDRREQ;
 825                         goto release;
 826                 }
 827
 828                 np->local_ip = in_dev->ifa_list->ifa_local;
 829                 rcu_read_unlock();
 830                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 831         }
 832
 833         if (np->rx_hook) {
 834                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 835                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 836                 list_add_tail(&np->rx, &npinfo->rx_np);
 837                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 838         }
 839
 840         /* fill up the skb queue */
 841         refill_skbs();
 842
 843         /* last thing to do is link it to the net device structure */
 844         ndev->npinfo = npinfo;
 845
 846         /* avoid racing with NAPI reading npinfo */
 847         synchronize_rcu();
 848
 849         return 0;
 850
 851  release:
 852         if (!ndev->npinfo) {
 853                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 854                 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
 855                         npe->dev = NULL;
 856                 }
 857                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 858
 859                 kfree(npinfo);
 860         }
 861 put:
 862         dev_put(ndev);
 863         return err;
 864 }
 865
 866 static int __init netpoll_init(void)
 867 {
 868         skb_queue_head_init(&skb_pool);
 869         return 0;
 870 }
 871 core_initcall(netpoll_init);
 872
 873 void netpoll_cleanup(struct netpoll *np)
 874 {
 875         struct netpoll_info *npinfo;
 876         unsigned long flags;
 877
 878         if (np->dev) {
 879                 npinfo = np->dev->npinfo;
 880                 if (npinfo) {
 881                         if (!list_empty(&npinfo->rx_np)) {
 882                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 883                                 list_del(&np->rx);
 884                                 if (list_empty(&npinfo->rx_np))
 885                                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 886                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 887                         }
 888
 889                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 890                                 const struct net_device_ops *ops;
 891                                 skb_queue_purge(&npinfo->arp_tx);
 892                                 skb_queue_purge(&npinfo->txq);
 893                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 894
 895                                 /* clean after last, unfinished work */
 896                                 __skb_queue_purge(&npinfo->txq);
 897                                 kfree(npinfo);
 898                                 ops = np->dev->netdev_ops;
 899                                 if (ops->ndo_netpoll_cleanup)
 900                                         ops->ndo_netpoll_cleanup(np->dev);
 901                                 else
 902                                         np->dev->npinfo = NULL;
 903                         }
 904                 }
 905
 906                 dev_put(np->dev);
 907         }
 908
 909         np->dev = NULL;
 910 }
 911
 912 int netpoll_trap(void)
 913 {
 914         return atomic_read(&trapped);
 915 }
 916
 917 void netpoll_set_trap(int trap)
 918 {
 919         if (trap)
 920                 atomic_inc(&trapped);
 921         else
 922                 atomic_dec(&trapped);
 923 }
 924
 925 EXPORT_SYMBOL(netpoll_send_skb);
 926 EXPORT_SYMBOL(netpoll_set_trap);
 927 EXPORT_SYMBOL(netpoll_trap);
 928 EXPORT_SYMBOL(netpoll_print_options);
 929 EXPORT_SYMBOL(netpoll_parse_options);
 930 EXPORT_SYMBOL(netpoll_setup);
 931 EXPORT_SYMBOL(netpoll_cleanup);
 932 EXPORT_SYMBOL(netpoll_send_udp);
 933 EXPORT_SYMBOL(netpoll_poll_dev);
 934 EXPORT_SYMBOL(netpoll_poll);