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 arp_reply(struct sk_buff *skb);
  53
  54 static unsigned int carrier_timeout = 4;
  55 module_param(carrier_timeout, uint, 0644);
  56
  57 static void queue_process(struct work_struct *work)
  58 {
  59         struct netpoll_info *npinfo =
  60                 container_of(work, struct netpoll_info, tx_work.work);
  61         struct sk_buff *skb;
  62         unsigned long flags;
  63
  64         while ((skb = skb_dequeue(&npinfo->txq))) {
  65                 struct net_device *dev = skb->dev;
  66                 const struct net_device_ops *ops = dev->netdev_ops;
  67                 struct netdev_queue *txq;
  68
  69                 if (!netif_device_present(dev) || !netif_running(dev)) {
  70                         __kfree_skb(skb);
  71                         continue;
  72                 }
  73
  74                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  75
  76                 local_irq_save(flags);
  77                 __netif_tx_lock(txq, smp_processor_id());
  78                 if (netif_tx_queue_stopped(txq) ||
  79                     netif_tx_queue_frozen(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 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         service_arp_queue(dev->npinfo);
 198
 199 }
 200
 201 void netpoll_poll(struct netpoll *np)
 202 {
 203         netpoll_poll_dev(np->dev);
 204 }
 205
 206 static void refill_skbs(void)
 207 {
 208         struct sk_buff *skb;
 209         unsigned long flags;
 210
 211         spin_lock_irqsave(&skb_pool.lock, flags);
 212         while (skb_pool.qlen < MAX_SKBS) {
 213                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 214                 if (!skb)
 215                         break;
 216
 217                 __skb_queue_tail(&skb_pool, skb);
 218         }
 219         spin_unlock_irqrestore(&skb_pool.lock, flags);
 220 }
 221
 222 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 223 {
 224         int count = 0;
 225         struct sk_buff *skb;
 226
 227         refill_skbs();
 228 repeat:
 229
 230         skb = alloc_skb(len, GFP_ATOMIC);
 231         if (!skb)
 232                 skb = skb_dequeue(&skb_pool);
 233
 234         if (!skb) {
 235                 if (++count < 10) {
 236                         netpoll_poll(np);
 237                         goto repeat;
 238                 }
 239                 return NULL;
 240         }
 241
 242         atomic_set(&skb->users, 1);
 243         skb_reserve(skb, reserve);
 244         return skb;
 245 }
 246
 247 static int netpoll_owner_active(struct net_device *dev)
 248 {
 249         struct napi_struct *napi;
 250
 251         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 252                 if (napi->poll_owner == smp_processor_id())
 253                         return 1;
 254         }
 255         return 0;
 256 }
 257
 258 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 259 {
 260         int status = NETDEV_TX_BUSY;
 261         unsigned long tries;
 262         struct net_device *dev = np->dev;
 263         const struct net_device_ops *ops = dev->netdev_ops;
 264         struct netpoll_info *npinfo = np->dev->npinfo;
 265
 266         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 267                 __kfree_skb(skb);
 268                 return;
 269         }
 270
 271         /* don't get messages out of order, and no recursion */
 272         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 273                 struct netdev_queue *txq;
 274                 unsigned long flags;
 275
 276                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 277
 278                 local_irq_save(flags);
 279                 /* try until next clock tick */
 280                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 281                      tries > 0; --tries) {
 282                         if (__netif_tx_trylock(txq)) {
 283                                 if (!netif_tx_queue_stopped(txq)) {
 284                                         dev->priv_flags |= IFF_IN_NETPOLL;
 285                                         status = ops->ndo_start_xmit(skb, dev);
 286                                         dev->priv_flags &= ~IFF_IN_NETPOLL;
 287                                         if (status == NETDEV_TX_OK)
 288                                                 txq_trans_update(txq);
 289                                 }
 290                                 __netif_tx_unlock(txq);
 291
 292                                 if (status == NETDEV_TX_OK)
 293                                         break;
 294
 295                         }
 296
 297                         /* tickle device maybe there is some cleanup */
 298                         netpoll_poll(np);
 299
 300                         udelay(USEC_PER_POLL);
 301                 }
 302
 303                 WARN_ONCE(!irqs_disabled(),
 304                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 305                         dev->name, ops->ndo_start_xmit);
 306
 307                 local_irq_restore(flags);
 308         }
 309
 310         if (status != NETDEV_TX_OK) {
 311                 skb_queue_tail(&npinfo->txq, skb);
 312                 schedule_delayed_work(&npinfo->tx_work,0);
 313         }
 314 }
 315
 316 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 317 {
 318         int total_len, eth_len, ip_len, udp_len;
 319         struct sk_buff *skb;
 320         struct udphdr *udph;
 321         struct iphdr *iph;
 322         struct ethhdr *eth;
 323
 324         udp_len = len + sizeof(*udph);
 325         ip_len = eth_len = udp_len + sizeof(*iph);
 326         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 327
 328         skb = find_skb(np, total_len, total_len - len);
 329         if (!skb)
 330                 return;
 331
 332         skb_copy_to_linear_data(skb, msg, len);
 333         skb->len += len;
 334
 335         skb_push(skb, sizeof(*udph));
 336         skb_reset_transport_header(skb);
 337         udph = udp_hdr(skb);
 338         udph->source = htons(np->local_port);
 339         udph->dest = htons(np->remote_port);
 340         udph->len = htons(udp_len);
 341         udph->check = 0;
 342         udph->check = csum_tcpudp_magic(np->local_ip,
 343                                         np->remote_ip,
 344                                         udp_len, IPPROTO_UDP,
 345                                         csum_partial(udph, udp_len, 0));
 346         if (udph->check == 0)
 347                 udph->check = CSUM_MANGLED_0;
 348
 349         skb_push(skb, sizeof(*iph));
 350         skb_reset_network_header(skb);
 351         iph = ip_hdr(skb);
 352
 353         /* iph->version = 4; iph->ihl = 5; */
 354         put_unaligned(0x45, (unsigned char *)iph);
 355         iph->tos      = 0;
 356         put_unaligned(htons(ip_len), &(iph->tot_len));
 357         iph->id       = 0;
 358         iph->frag_off = 0;
 359         iph->ttl      = 64;
 360         iph->protocol = IPPROTO_UDP;
 361         iph->check    = 0;
 362         put_unaligned(np->local_ip, &(iph->saddr));
 363         put_unaligned(np->remote_ip, &(iph->daddr));
 364         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 365
 366         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 367         skb_reset_mac_header(skb);
 368         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 369         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 370         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 371
 372         skb->dev = np->dev;
 373
 374         netpoll_send_skb(np, skb);
 375 }
 376
 377 static void arp_reply(struct sk_buff *skb)
 378 {
 379         struct netpoll_info *npinfo = skb->dev->npinfo;
 380         struct arphdr *arp;
 381         unsigned char *arp_ptr;
 382         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 383         __be32 sip, tip;
 384         unsigned char *sha;
 385         struct sk_buff *send_skb;
 386         struct netpoll *np, *tmp;
 387         unsigned long flags;
 388         int hits = 0;
 389
 390         if (list_empty(&npinfo->rx_np))
 391                 return;
 392
 393         /* Before checking the packet, we do some early
 394            inspection whether this is interesting at all */
 395         spin_lock_irqsave(&npinfo->rx_lock, flags);
 396         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 397                 if (np->dev == skb->dev)
 398                         hits++;
 399         }
 400         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 401
 402         /* No netpoll struct is using this dev */
 403         if (!hits)
 404                 return;
 405
 406         /* No arp on this interface */
 407         if (skb->dev->flags & IFF_NOARP)
 408                 return;
 409
 410         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 411                 return;
 412
 413         skb_reset_network_header(skb);
 414         skb_reset_transport_header(skb);
 415         arp = arp_hdr(skb);
 416
 417         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 418              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 419             arp->ar_pro != htons(ETH_P_IP) ||
 420             arp->ar_op != htons(ARPOP_REQUEST))
 421                 return;
 422
 423         arp_ptr = (unsigned char *)(arp+1);
 424         /* save the location of the src hw addr */
 425         sha = arp_ptr;
 426         arp_ptr += skb->dev->addr_len;
 427         memcpy(&sip, arp_ptr, 4);
 428         arp_ptr += 4;
 429         /* If we actually cared about dst hw addr,
 430            it would get copied here */
 431         arp_ptr += skb->dev->addr_len;
 432         memcpy(&tip, arp_ptr, 4);
 433
 434         /* Should we ignore arp? */
 435         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 436                 return;
 437
 438         size = arp_hdr_len(skb->dev);
 439
 440         spin_lock_irqsave(&npinfo->rx_lock, flags);
 441         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 442                 if (tip != np->local_ip)
 443                         continue;
 444
 445                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 446                                     LL_RESERVED_SPACE(np->dev));
 447                 if (!send_skb)
 448                         continue;
 449
 450                 skb_reset_network_header(send_skb);
 451                 arp = (struct arphdr *) skb_put(send_skb, size);
 452                 send_skb->dev = skb->dev;
 453                 send_skb->protocol = htons(ETH_P_ARP);
 454
 455                 /* Fill the device header for the ARP frame */
 456                 if (dev_hard_header(send_skb, skb->dev, ptype,
 457                                     sha, np->dev->dev_addr,
 458                                     send_skb->len) < 0) {
 459                         kfree_skb(send_skb);
 460                         continue;
 461                 }
 462
 463                 /*
 464                  * Fill out the arp protocol part.
 465                  *
 466                  * we only support ethernet device type,
 467                  * which (according to RFC 1390) should
 468                  * always equal 1 (Ethernet).
 469                  */
 470
 471                 arp->ar_hrd = htons(np->dev->type);
 472                 arp->ar_pro = htons(ETH_P_IP);
 473                 arp->ar_hln = np->dev->addr_len;
 474                 arp->ar_pln = 4;
 475                 arp->ar_op = htons(type);
 476
 477                 arp_ptr = (unsigned char *)(arp + 1);
 478                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 479                 arp_ptr += np->dev->addr_len;
 480                 memcpy(arp_ptr, &tip, 4);
 481                 arp_ptr += 4;
 482                 memcpy(arp_ptr, sha, np->dev->addr_len);
 483                 arp_ptr += np->dev->addr_len;
 484                 memcpy(arp_ptr, &sip, 4);
 485
 486                 netpoll_send_skb(np, send_skb);
 487
 488                 /* If there are several rx_hooks for the same address,
 489                    we're fine by sending a single reply */
 490                 break;
 491         }
 492         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 493 }
 494
 495 int __netpoll_rx(struct sk_buff *skb)
 496 {
 497         int proto, len, ulen;
 498         int hits = 0;
 499         struct iphdr *iph;
 500         struct udphdr *uh;
 501         struct netpoll_info *npinfo = skb->dev->npinfo;
 502         struct netpoll *np, *tmp;
 503
 504         if (list_empty(&npinfo->rx_np))
 505                 goto out;
 506
 507         if (skb->dev->type != ARPHRD_ETHER)
 508                 goto out;
 509
 510         /* check if netpoll clients need ARP */
 511         if (skb->protocol == htons(ETH_P_ARP) &&
 512             atomic_read(&trapped)) {
 513                 skb_queue_tail(&npinfo->arp_tx, skb);
 514                 return 1;
 515         }
 516
 517         proto = ntohs(eth_hdr(skb)->h_proto);
 518         if (proto != ETH_P_IP)
 519                 goto out;
 520         if (skb->pkt_type == PACKET_OTHERHOST)
 521                 goto out;
 522         if (skb_shared(skb))
 523                 goto out;
 524
 525         iph = (struct iphdr *)skb->data;
 526         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 527                 goto out;
 528         if (iph->ihl < 5 || iph->version != 4)
 529                 goto out;
 530         if (!pskb_may_pull(skb, iph->ihl*4))
 531                 goto out;
 532         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 533                 goto out;
 534
 535         len = ntohs(iph->tot_len);
 536         if (skb->len < len || len < iph->ihl*4)
 537                 goto out;
 538
 539         /*
 540          * Our transport medium may have padded the buffer out.
 541          * Now We trim to the true length of the frame.
 542          */
 543         if (pskb_trim_rcsum(skb, len))
 544                 goto out;
 545
 546         if (iph->protocol != IPPROTO_UDP)
 547                 goto out;
 548
 549         len -= iph->ihl*4;
 550         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 551         ulen = ntohs(uh->len);
 552
 553         if (ulen != len)
 554                 goto out;
 555         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 556                 goto out;
 557
 558         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 559                 if (np->local_ip && np->local_ip != iph->daddr)
 560                         continue;
 561                 if (np->remote_ip && np->remote_ip != iph->saddr)
 562                         continue;
 563                 if (np->local_port && np->local_port != ntohs(uh->dest))
 564                         continue;
 565
 566                 np->rx_hook(np, ntohs(uh->source),
 567                                (char *)(uh+1),
 568                                ulen - sizeof(struct udphdr));
 569                 hits++;
 570         }
 571
 572         if (!hits)
 573                 goto out;
 574
 575         kfree_skb(skb);
 576         return 1;
 577
 578 out:
 579         if (atomic_read(&trapped)) {
 580                 kfree_skb(skb);
 581                 return 1;
 582         }
 583
 584         return 0;
 585 }
 586
 587 void netpoll_print_options(struct netpoll *np)
 588 {
 589         printk(KERN_INFO "%s: local port %d\n",
 590                          np->name, np->local_port);
 591         printk(KERN_INFO "%s: local IP %pI4\n",
 592                          np->name, &np->local_ip);
 593         printk(KERN_INFO "%s: interface '%s'\n",
 594                          np->name, np->dev_name);
 595         printk(KERN_INFO "%s: remote port %d\n",
 596                          np->name, np->remote_port);
 597         printk(KERN_INFO "%s: remote IP %pI4\n",
 598                          np->name, &np->remote_ip);
 599         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 600                          np->name, np->remote_mac);
 601 }
 602
 603 int netpoll_parse_options(struct netpoll *np, char *opt)
 604 {
 605         char *cur=opt, *delim;
 606
 607         if (*cur != '@') {
 608                 if ((delim = strchr(cur, '@')) == NULL)
 609                         goto parse_failed;
 610                 *delim = 0;
 611                 np->local_port = simple_strtol(cur, NULL, 10);
 612                 cur = delim;
 613         }
 614         cur++;
 615
 616         if (*cur != '/') {
 617                 if ((delim = strchr(cur, '/')) == NULL)
 618                         goto parse_failed;
 619                 *delim = 0;
 620                 np->local_ip = in_aton(cur);
 621                 cur = delim;
 622         }
 623         cur++;
 624
 625         if (*cur != ',') {
 626                 /* parse out dev name */
 627                 if ((delim = strchr(cur, ',')) == NULL)
 628                         goto parse_failed;
 629                 *delim = 0;
 630                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 631                 cur = delim;
 632         }
 633         cur++;
 634
 635         if (*cur != '@') {
 636                 /* dst port */
 637                 if ((delim = strchr(cur, '@')) == NULL)
 638                         goto parse_failed;
 639                 *delim = 0;
 640                 if (*cur == ' ' || *cur == '\t')
 641                         printk(KERN_INFO "%s: warning: whitespace"
 642                                         "is not allowed\n", np->name);
 643                 np->remote_port = simple_strtol(cur, NULL, 10);
 644                 cur = delim;
 645         }
 646         cur++;
 647
 648         /* dst ip */
 649         if ((delim = strchr(cur, '/')) == NULL)
 650                 goto parse_failed;
 651         *delim = 0;
 652         np->remote_ip = in_aton(cur);
 653         cur = delim + 1;
 654
 655         if (*cur != 0) {
 656                 /* MAC address */
 657                 if ((delim = strchr(cur, ':')) == NULL)
 658                         goto parse_failed;
 659                 *delim = 0;
 660                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 661                 cur = delim + 1;
 662                 if ((delim = strchr(cur, ':')) == NULL)
 663                         goto parse_failed;
 664                 *delim = 0;
 665                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 666                 cur = delim + 1;
 667                 if ((delim = strchr(cur, ':')) == NULL)
 668                         goto parse_failed;
 669                 *delim = 0;
 670                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 671                 cur = delim + 1;
 672                 if ((delim = strchr(cur, ':')) == NULL)
 673                         goto parse_failed;
 674                 *delim = 0;
 675                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 676                 cur = delim + 1;
 677                 if ((delim = strchr(cur, ':')) == NULL)
 678                         goto parse_failed;
 679                 *delim = 0;
 680                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 681                 cur = delim + 1;
 682                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 683         }
 684
 685         netpoll_print_options(np);
 686
 687         return 0;
 688
 689  parse_failed:
 690         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 691                np->name, cur);
 692         return -1;
 693 }
 694
 695 int netpoll_setup(struct netpoll *np)
 696 {
 697         struct net_device *ndev = NULL;
 698         struct in_device *in_dev;
 699         struct netpoll_info *npinfo;
 700         struct netpoll *npe, *tmp;
 701         unsigned long flags;
 702         int err;
 703
 704         if (np->dev_name)
 705                 ndev = dev_get_by_name(&init_net, np->dev_name);
 706         if (!ndev) {
 707                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 708                        np->name, np->dev_name);
 709                 return -ENODEV;
 710         }
 711
 712         np->dev = ndev;
 713         if (!ndev->npinfo) {
 714                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 715                 if (!npinfo) {
 716                         err = -ENOMEM;
 717                         goto put;
 718                 }
 719
 720                 npinfo->rx_flags = 0;
 721                 INIT_LIST_HEAD(&npinfo->rx_np);
 722
 723                 spin_lock_init(&npinfo->rx_lock);
 724                 skb_queue_head_init(&npinfo->arp_tx);
 725                 skb_queue_head_init(&npinfo->txq);
 726                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 727
 728                 atomic_set(&npinfo->refcnt, 1);
 729         } else {
 730                 npinfo = ndev->npinfo;
 731                 atomic_inc(&npinfo->refcnt);
 732         }
 733
 734         npinfo->netpoll = np;
 735
 736         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 737             !ndev->netdev_ops->ndo_poll_controller) {
 738                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 739                        np->name, np->dev_name);
 740                 err = -ENOTSUPP;
 741                 goto release;
 742         }
 743
 744         if (!netif_running(ndev)) {
 745                 unsigned long atmost, atleast;
 746
 747                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 748                        np->name, np->dev_name);
 749
 750                 rtnl_lock();
 751                 err = dev_open(ndev);
 752                 rtnl_unlock();
 753
 754                 if (err) {
 755                         printk(KERN_ERR "%s: failed to open %s\n",
 756                                np->name, ndev->name);
 757                         goto release;
 758                 }
 759
 760                 atleast = jiffies + HZ/10;
 761                 atmost = jiffies + carrier_timeout * HZ;
 762                 while (!netif_carrier_ok(ndev)) {
 763                         if (time_after(jiffies, atmost)) {
 764                                 printk(KERN_NOTICE
 765                                        "%s: timeout waiting for carrier\n",
 766                                        np->name);
 767                                 break;
 768                         }
 769                         msleep(1);
 770                 }
 771
 772                 /* If carrier appears to come up instantly, we don't
 773                  * trust it and pause so that we don't pump all our
 774                  * queued console messages into the bitbucket.
 775                  */
 776
 777                 if (time_before(jiffies, atleast)) {
 778                         printk(KERN_NOTICE "%s: carrier detect appears"
 779                                " untrustworthy, waiting 4 seconds\n",
 780                                np->name);
 781                         msleep(4000);
 782                 }
 783         }
 784
 785         if (!np->local_ip) {
 786                 rcu_read_lock();
 787                 in_dev = __in_dev_get_rcu(ndev);
 788
 789                 if (!in_dev || !in_dev->ifa_list) {
 790                         rcu_read_unlock();
 791                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 792                                np->name, np->dev_name);
 793                         err = -EDESTADDRREQ;
 794                         goto release;
 795                 }
 796
 797                 np->local_ip = in_dev->ifa_list->ifa_local;
 798                 rcu_read_unlock();
 799                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 800         }
 801
 802         if (np->rx_hook) {
 803                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 804                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 805                 list_add_tail(&np->rx, &npinfo->rx_np);
 806                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 807         }
 808
 809         /* fill up the skb queue */
 810         refill_skbs();
 811
 812         /* last thing to do is link it to the net device structure */
 813         ndev->npinfo = npinfo;
 814
 815         /* avoid racing with NAPI reading npinfo */
 816         synchronize_rcu();
 817
 818         return 0;
 819
 820  release:
 821         if (!ndev->npinfo) {
 822                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 823                 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
 824                         npe->dev = NULL;
 825                 }
 826                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 827
 828                 kfree(npinfo);
 829         }
 830 put:
 831         dev_put(ndev);
 832         return err;
 833 }
 834
 835 static int __init netpoll_init(void)
 836 {
 837         skb_queue_head_init(&skb_pool);
 838         return 0;
 839 }
 840 core_initcall(netpoll_init);
 841
 842 void netpoll_cleanup(struct netpoll *np)
 843 {
 844         struct netpoll_info *npinfo;
 845         unsigned long flags;
 846
 847         if (np->dev) {
 848                 npinfo = np->dev->npinfo;
 849                 if (npinfo) {
 850                         if (!list_empty(&npinfo->rx_np)) {
 851                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 852                                 list_del(&np->rx);
 853                                 if (list_empty(&npinfo->rx_np))
 854                                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 855                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 856                         }
 857
 858                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 859                                 const struct net_device_ops *ops;
 860                                 skb_queue_purge(&npinfo->arp_tx);
 861                                 skb_queue_purge(&npinfo->txq);
 862                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 863
 864                                 /* clean after last, unfinished work */
 865                                 __skb_queue_purge(&npinfo->txq);
 866                                 kfree(npinfo);
 867                                 ops = np->dev->netdev_ops;
 868                                 if (ops->ndo_netpoll_cleanup)
 869                                         ops->ndo_netpoll_cleanup(np->dev);
 870                                 else
 871                                         np->dev->npinfo = NULL;
 872                         }
 873                 }
 874
 875                 dev_put(np->dev);
 876         }
 877
 878         np->dev = NULL;
 879 }
 880
 881 int netpoll_trap(void)
 882 {
 883         return atomic_read(&trapped);
 884 }
 885
 886 void netpoll_set_trap(int trap)
 887 {
 888         if (trap)
 889                 atomic_inc(&trapped);
 890         else
 891                 atomic_dec(&trapped);
 892 }
 893
 894 EXPORT_SYMBOL(netpoll_send_skb);
 895 EXPORT_SYMBOL(netpoll_set_trap);
 896 EXPORT_SYMBOL(netpoll_trap);
 897 EXPORT_SYMBOL(netpoll_print_options);
 898 EXPORT_SYMBOL(netpoll_parse_options);
 899 EXPORT_SYMBOL(netpoll_setup);
 900 EXPORT_SYMBOL(netpoll_cleanup);
 901 EXPORT_SYMBOL(netpoll_send_udp);
 902 EXPORT_SYMBOL(netpoll_poll_dev);
 903 EXPORT_SYMBOL(netpoll_poll);