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 <net/tcp.h>
  26 #include <net/udp.h>
  27 #include <asm/unaligned.h>
  28 #include <trace/events/napi.h>
  29
  30 /*
  31  * We maintain a small pool of fully-sized skbs, to make sure the
  32  * message gets out even in extreme OOM situations.
  33  */
  34
  35 #define MAX_UDP_CHUNK 1460
  36 #define MAX_SKBS 32
  37 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
  38
  39 static struct sk_buff_head skb_pool;
  40
  41 static atomic_t trapped;
  42
  43 #define USEC_PER_POLL   50
  44 #define NETPOLL_RX_ENABLED  1
  45 #define NETPOLL_RX_DROP     2
  46
  47 #define MAX_SKB_SIZE \
  48                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
  49                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
  50
  51 static void zap_completion_queue(void);
  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(struct netpoll *np)
 182 {
 183         struct net_device *dev = np->dev;
 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 static void refill_skbs(void)
 204 {
 205         struct sk_buff *skb;
 206         unsigned long flags;
 207
 208         spin_lock_irqsave(&skb_pool.lock, flags);
 209         while (skb_pool.qlen < MAX_SKBS) {
 210                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 211                 if (!skb)
 212                         break;
 213
 214                 __skb_queue_tail(&skb_pool, skb);
 215         }
 216         spin_unlock_irqrestore(&skb_pool.lock, flags);
 217 }
 218
 219 static void zap_completion_queue(void)
 220 {
 221         unsigned long flags;
 222         struct softnet_data *sd = &get_cpu_var(softnet_data);
 223
 224         if (sd->completion_queue) {
 225                 struct sk_buff *clist;
 226
 227                 local_irq_save(flags);
 228                 clist = sd->completion_queue;
 229                 sd->completion_queue = NULL;
 230                 local_irq_restore(flags);
 231
 232                 while (clist != NULL) {
 233                         struct sk_buff *skb = clist;
 234                         clist = clist->next;
 235                         if (skb->destructor) {
 236                                 atomic_inc(&skb->users);
 237                                 dev_kfree_skb_any(skb); /* put this one back */
 238                         } else {
 239                                 __kfree_skb(skb);
 240                         }
 241                 }
 242         }
 243
 244         put_cpu_var(softnet_data);
 245 }
 246
 247 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 248 {
 249         int count = 0;
 250         struct sk_buff *skb;
 251
 252         zap_completion_queue();
 253         refill_skbs();
 254 repeat:
 255
 256         skb = alloc_skb(len, GFP_ATOMIC);
 257         if (!skb)
 258                 skb = skb_dequeue(&skb_pool);
 259
 260         if (!skb) {
 261                 if (++count < 10) {
 262                         netpoll_poll(np);
 263                         goto repeat;
 264                 }
 265                 return NULL;
 266         }
 267
 268         atomic_set(&skb->users, 1);
 269         skb_reserve(skb, reserve);
 270         return skb;
 271 }
 272
 273 static int netpoll_owner_active(struct net_device *dev)
 274 {
 275         struct napi_struct *napi;
 276
 277         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 278                 if (napi->poll_owner == smp_processor_id())
 279                         return 1;
 280         }
 281         return 0;
 282 }
 283
 284 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 285 {
 286         int status = NETDEV_TX_BUSY;
 287         unsigned long tries;
 288         struct net_device *dev = np->dev;
 289         const struct net_device_ops *ops = dev->netdev_ops;
 290         struct netpoll_info *npinfo = np->dev->npinfo;
 291
 292         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 293                 __kfree_skb(skb);
 294                 return;
 295         }
 296
 297         /* don't get messages out of order, and no recursion */
 298         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 299                 struct netdev_queue *txq;
 300                 unsigned long flags;
 301
 302                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 303
 304                 local_irq_save(flags);
 305                 /* try until next clock tick */
 306                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 307                      tries > 0; --tries) {
 308                         if (__netif_tx_trylock(txq)) {
 309                                 if (!netif_tx_queue_stopped(txq)) {
 310                                         status = ops->ndo_start_xmit(skb, dev);
 311                                         if (status == NETDEV_TX_OK)
 312                                                 txq_trans_update(txq);
 313                                 }
 314                                 __netif_tx_unlock(txq);
 315
 316                                 if (status == NETDEV_TX_OK)
 317                                         break;
 318
 319                         }
 320
 321                         /* tickle device maybe there is some cleanup */
 322                         netpoll_poll(np);
 323
 324                         udelay(USEC_PER_POLL);
 325                 }
 326
 327                 WARN_ONCE(!irqs_disabled(),
 328                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 329                         dev->name, ops->ndo_start_xmit);
 330
 331                 local_irq_restore(flags);
 332         }
 333
 334         if (status != NETDEV_TX_OK) {
 335                 skb_queue_tail(&npinfo->txq, skb);
 336                 schedule_delayed_work(&npinfo->tx_work,0);
 337         }
 338 }
 339
 340 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 341 {
 342         int total_len, eth_len, ip_len, udp_len;
 343         struct sk_buff *skb;
 344         struct udphdr *udph;
 345         struct iphdr *iph;
 346         struct ethhdr *eth;
 347
 348         udp_len = len + sizeof(*udph);
 349         ip_len = eth_len = udp_len + sizeof(*iph);
 350         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 351
 352         skb = find_skb(np, total_len, total_len - len);
 353         if (!skb)
 354                 return;
 355
 356         skb_copy_to_linear_data(skb, msg, len);
 357         skb->len += len;
 358
 359         skb_push(skb, sizeof(*udph));
 360         skb_reset_transport_header(skb);
 361         udph = udp_hdr(skb);
 362         udph->source = htons(np->local_port);
 363         udph->dest = htons(np->remote_port);
 364         udph->len = htons(udp_len);
 365         udph->check = 0;
 366         udph->check = csum_tcpudp_magic(np->local_ip,
 367                                         np->remote_ip,
 368                                         udp_len, IPPROTO_UDP,
 369                                         csum_partial(udph, udp_len, 0));
 370         if (udph->check == 0)
 371                 udph->check = CSUM_MANGLED_0;
 372
 373         skb_push(skb, sizeof(*iph));
 374         skb_reset_network_header(skb);
 375         iph = ip_hdr(skb);
 376
 377         /* iph->version = 4; iph->ihl = 5; */
 378         put_unaligned(0x45, (unsigned char *)iph);
 379         iph->tos      = 0;
 380         put_unaligned(htons(ip_len), &(iph->tot_len));
 381         iph->id       = 0;
 382         iph->frag_off = 0;
 383         iph->ttl      = 64;
 384         iph->protocol = IPPROTO_UDP;
 385         iph->check    = 0;
 386         put_unaligned(np->local_ip, &(iph->saddr));
 387         put_unaligned(np->remote_ip, &(iph->daddr));
 388         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 389
 390         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 391         skb_reset_mac_header(skb);
 392         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 393         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 394         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 395
 396         skb->dev = np->dev;
 397
 398         netpoll_send_skb(np, skb);
 399 }
 400
 401 static void arp_reply(struct sk_buff *skb)
 402 {
 403         struct netpoll_info *npinfo = skb->dev->npinfo;
 404         struct arphdr *arp;
 405         unsigned char *arp_ptr;
 406         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 407         __be32 sip, tip;
 408         unsigned char *sha;
 409         struct sk_buff *send_skb;
 410         struct netpoll *np = NULL;
 411
 412         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 413                 np = npinfo->rx_np;
 414         if (!np)
 415                 return;
 416
 417         /* No arp on this interface */
 418         if (skb->dev->flags & IFF_NOARP)
 419                 return;
 420
 421         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 422                 return;
 423
 424         skb_reset_network_header(skb);
 425         skb_reset_transport_header(skb);
 426         arp = arp_hdr(skb);
 427
 428         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 429              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 430             arp->ar_pro != htons(ETH_P_IP) ||
 431             arp->ar_op != htons(ARPOP_REQUEST))
 432                 return;
 433
 434         arp_ptr = (unsigned char *)(arp+1);
 435         /* save the location of the src hw addr */
 436         sha = arp_ptr;
 437         arp_ptr += skb->dev->addr_len;
 438         memcpy(&sip, arp_ptr, 4);
 439         arp_ptr += 4;
 440         /* if we actually cared about dst hw addr, it would get copied here */
 441         arp_ptr += skb->dev->addr_len;
 442         memcpy(&tip, arp_ptr, 4);
 443
 444         /* Should we ignore arp? */
 445         if (tip != np->local_ip ||
 446             ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 447                 return;
 448
 449         size = arp_hdr_len(skb->dev);
 450         send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 451                             LL_RESERVED_SPACE(np->dev));
 452
 453         if (!send_skb)
 454                 return;
 455
 456         skb_reset_network_header(send_skb);
 457         arp = (struct arphdr *) skb_put(send_skb, size);
 458         send_skb->dev = skb->dev;
 459         send_skb->protocol = htons(ETH_P_ARP);
 460
 461         /* Fill the device header for the ARP frame */
 462         if (dev_hard_header(send_skb, skb->dev, ptype,
 463                             sha, np->dev->dev_addr,
 464                             send_skb->len) < 0) {
 465                 kfree_skb(send_skb);
 466                 return;
 467         }
 468
 469         /*
 470          * Fill out the arp protocol part.
 471          *
 472          * we only support ethernet device type,
 473          * which (according to RFC 1390) should always equal 1 (Ethernet).
 474          */
 475
 476         arp->ar_hrd = htons(np->dev->type);
 477         arp->ar_pro = htons(ETH_P_IP);
 478         arp->ar_hln = np->dev->addr_len;
 479         arp->ar_pln = 4;
 480         arp->ar_op = htons(type);
 481
 482         arp_ptr=(unsigned char *)(arp + 1);
 483         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 484         arp_ptr += np->dev->addr_len;
 485         memcpy(arp_ptr, &tip, 4);
 486         arp_ptr += 4;
 487         memcpy(arp_ptr, sha, np->dev->addr_len);
 488         arp_ptr += np->dev->addr_len;
 489         memcpy(arp_ptr, &sip, 4);
 490
 491         netpoll_send_skb(np, send_skb);
 492 }
 493
 494 int __netpoll_rx(struct sk_buff *skb)
 495 {
 496         int proto, len, ulen;
 497         struct iphdr *iph;
 498         struct udphdr *uh;
 499         struct netpoll_info *npi = skb->dev->npinfo;
 500         struct netpoll *np = npi->rx_np;
 501
 502         if (!np)
 503                 goto out;
 504         if (skb->dev->type != ARPHRD_ETHER)
 505                 goto out;
 506
 507         /* check if netpoll clients need ARP */
 508         if (skb->protocol == htons(ETH_P_ARP) &&
 509             atomic_read(&trapped)) {
 510                 skb_queue_tail(&npi->arp_tx, skb);
 511                 return 1;
 512         }
 513
 514         proto = ntohs(eth_hdr(skb)->h_proto);
 515         if (proto != ETH_P_IP)
 516                 goto out;
 517         if (skb->pkt_type == PACKET_OTHERHOST)
 518                 goto out;
 519         if (skb_shared(skb))
 520                 goto out;
 521
 522         iph = (struct iphdr *)skb->data;
 523         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 524                 goto out;
 525         if (iph->ihl < 5 || iph->version != 4)
 526                 goto out;
 527         if (!pskb_may_pull(skb, iph->ihl*4))
 528                 goto out;
 529         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 530                 goto out;
 531
 532         len = ntohs(iph->tot_len);
 533         if (skb->len < len || len < iph->ihl*4)
 534                 goto out;
 535
 536         /*
 537          * Our transport medium may have padded the buffer out.
 538          * Now We trim to the true length of the frame.
 539          */
 540         if (pskb_trim_rcsum(skb, len))
 541                 goto out;
 542
 543         if (iph->protocol != IPPROTO_UDP)
 544                 goto out;
 545
 546         len -= iph->ihl*4;
 547         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 548         ulen = ntohs(uh->len);
 549
 550         if (ulen != len)
 551                 goto out;
 552         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 553                 goto out;
 554         if (np->local_ip && np->local_ip != iph->daddr)
 555                 goto out;
 556         if (np->remote_ip && np->remote_ip != iph->saddr)
 557                 goto out;
 558         if (np->local_port && np->local_port != ntohs(uh->dest))
 559                 goto out;
 560
 561         np->rx_hook(np, ntohs(uh->source),
 562                     (char *)(uh+1),
 563                     ulen - sizeof(struct udphdr));
 564
 565         kfree_skb(skb);
 566         return 1;
 567
 568 out:
 569         if (atomic_read(&trapped)) {
 570                 kfree_skb(skb);
 571                 return 1;
 572         }
 573
 574         return 0;
 575 }
 576
 577 void netpoll_print_options(struct netpoll *np)
 578 {
 579         printk(KERN_INFO "%s: local port %d\n",
 580                          np->name, np->local_port);
 581         printk(KERN_INFO "%s: local IP %pI4\n",
 582                          np->name, &np->local_ip);
 583         printk(KERN_INFO "%s: interface %s\n",
 584                          np->name, np->dev_name);
 585         printk(KERN_INFO "%s: remote port %d\n",
 586                          np->name, np->remote_port);
 587         printk(KERN_INFO "%s: remote IP %pI4\n",
 588                          np->name, &np->remote_ip);
 589         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 590                          np->name, np->remote_mac);
 591 }
 592
 593 int netpoll_parse_options(struct netpoll *np, char *opt)
 594 {
 595         char *cur=opt, *delim;
 596
 597         if (*cur != '@') {
 598                 if ((delim = strchr(cur, '@')) == NULL)
 599                         goto parse_failed;
 600                 *delim = 0;
 601                 np->local_port = simple_strtol(cur, NULL, 10);
 602                 cur = delim;
 603         }
 604         cur++;
 605
 606         if (*cur != '/') {
 607                 if ((delim = strchr(cur, '/')) == NULL)
 608                         goto parse_failed;
 609                 *delim = 0;
 610                 np->local_ip = in_aton(cur);
 611                 cur = delim;
 612         }
 613         cur++;
 614
 615         if (*cur != ',') {
 616                 /* parse out dev name */
 617                 if ((delim = strchr(cur, ',')) == NULL)
 618                         goto parse_failed;
 619                 *delim = 0;
 620                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 621                 cur = delim;
 622         }
 623         cur++;
 624
 625         if (*cur != '@') {
 626                 /* dst port */
 627                 if ((delim = strchr(cur, '@')) == NULL)
 628                         goto parse_failed;
 629                 *delim = 0;
 630                 np->remote_port = simple_strtol(cur, NULL, 10);
 631                 cur = delim;
 632         }
 633         cur++;
 634
 635         /* dst ip */
 636         if ((delim = strchr(cur, '/')) == NULL)
 637                 goto parse_failed;
 638         *delim = 0;
 639         np->remote_ip = in_aton(cur);
 640         cur = delim + 1;
 641
 642         if (*cur != 0) {
 643                 /* MAC address */
 644                 if ((delim = strchr(cur, ':')) == NULL)
 645                         goto parse_failed;
 646                 *delim = 0;
 647                 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
 648                 cur = delim + 1;
 649                 if ((delim = strchr(cur, ':')) == NULL)
 650                         goto parse_failed;
 651                 *delim = 0;
 652                 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
 653                 cur = delim + 1;
 654                 if ((delim = strchr(cur, ':')) == NULL)
 655                         goto parse_failed;
 656                 *delim = 0;
 657                 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
 658                 cur = delim + 1;
 659                 if ((delim = strchr(cur, ':')) == NULL)
 660                         goto parse_failed;
 661                 *delim = 0;
 662                 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
 663                 cur = delim + 1;
 664                 if ((delim = strchr(cur, ':')) == NULL)
 665                         goto parse_failed;
 666                 *delim = 0;
 667                 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
 668                 cur = delim + 1;
 669                 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
 670         }
 671
 672         netpoll_print_options(np);
 673
 674         return 0;
 675
 676  parse_failed:
 677         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
 678                np->name, cur);
 679         return -1;
 680 }
 681
 682 int netpoll_setup(struct netpoll *np)
 683 {
 684         struct net_device *ndev = NULL;
 685         struct in_device *in_dev;
 686         struct netpoll_info *npinfo;
 687         unsigned long flags;
 688         int err;
 689
 690         if (np->dev_name)
 691                 ndev = dev_get_by_name(&init_net, np->dev_name);
 692         if (!ndev) {
 693                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 694                        np->name, np->dev_name);
 695                 return -ENODEV;
 696         }
 697
 698         np->dev = ndev;
 699         if (!ndev->npinfo) {
 700                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 701                 if (!npinfo) {
 702                         err = -ENOMEM;
 703                         goto release;
 704                 }
 705
 706                 npinfo->rx_flags = 0;
 707                 npinfo->rx_np = NULL;
 708
 709                 spin_lock_init(&npinfo->rx_lock);
 710                 skb_queue_head_init(&npinfo->arp_tx);
 711                 skb_queue_head_init(&npinfo->txq);
 712                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 713
 714                 atomic_set(&npinfo->refcnt, 1);
 715         } else {
 716                 npinfo = ndev->npinfo;
 717                 atomic_inc(&npinfo->refcnt);
 718         }
 719
 720         if (!ndev->netdev_ops->ndo_poll_controller) {
 721                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 722                        np->name, np->dev_name);
 723                 err = -ENOTSUPP;
 724                 goto release;
 725         }
 726
 727         if (!netif_running(ndev)) {
 728                 unsigned long atmost, atleast;
 729
 730                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 731                        np->name, np->dev_name);
 732
 733                 rtnl_lock();
 734                 err = dev_open(ndev);
 735                 rtnl_unlock();
 736
 737                 if (err) {
 738                         printk(KERN_ERR "%s: failed to open %s\n",
 739                                np->name, ndev->name);
 740                         goto release;
 741                 }
 742
 743                 atleast = jiffies + HZ/10;
 744                 atmost = jiffies + carrier_timeout * HZ;
 745                 while (!netif_carrier_ok(ndev)) {
 746                         if (time_after(jiffies, atmost)) {
 747                                 printk(KERN_NOTICE
 748                                        "%s: timeout waiting for carrier\n",
 749                                        np->name);
 750                                 break;
 751                         }
 752                         msleep(1);
 753                 }
 754
 755                 /* If carrier appears to come up instantly, we don't
 756                  * trust it and pause so that we don't pump all our
 757                  * queued console messages into the bitbucket.
 758                  */
 759
 760                 if (time_before(jiffies, atleast)) {
 761                         printk(KERN_NOTICE "%s: carrier detect appears"
 762                                " untrustworthy, waiting 4 seconds\n",
 763                                np->name);
 764                         msleep(4000);
 765                 }
 766         }
 767
 768         if (!np->local_ip) {
 769                 rcu_read_lock();
 770                 in_dev = __in_dev_get_rcu(ndev);
 771
 772                 if (!in_dev || !in_dev->ifa_list) {
 773                         rcu_read_unlock();
 774                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 775                                np->name, np->dev_name);
 776                         err = -EDESTADDRREQ;
 777                         goto release;
 778                 }
 779
 780                 np->local_ip = in_dev->ifa_list->ifa_local;
 781                 rcu_read_unlock();
 782                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 783         }
 784
 785         if (np->rx_hook) {
 786                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 787                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 788                 npinfo->rx_np = np;
 789                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 790         }
 791
 792         /* fill up the skb queue */
 793         refill_skbs();
 794
 795         /* last thing to do is link it to the net device structure */
 796         ndev->npinfo = npinfo;
 797
 798         /* avoid racing with NAPI reading npinfo */
 799         synchronize_rcu();
 800
 801         return 0;
 802
 803  release:
 804         if (!ndev->npinfo)
 805                 kfree(npinfo);
 806         np->dev = NULL;
 807         dev_put(ndev);
 808         return err;
 809 }
 810
 811 static int __init netpoll_init(void)
 812 {
 813         skb_queue_head_init(&skb_pool);
 814         return 0;
 815 }
 816 core_initcall(netpoll_init);
 817
 818 void netpoll_cleanup(struct netpoll *np)
 819 {
 820         struct netpoll_info *npinfo;
 821         unsigned long flags;
 822
 823         if (np->dev) {
 824                 npinfo = np->dev->npinfo;
 825                 if (npinfo) {
 826                         if (npinfo->rx_np == np) {
 827                                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 828                                 npinfo->rx_np = NULL;
 829                                 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 830                                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 831                         }
 832
 833                         if (atomic_dec_and_test(&npinfo->refcnt)) {
 834                                 skb_queue_purge(&npinfo->arp_tx);
 835                                 skb_queue_purge(&npinfo->txq);
 836                                 cancel_rearming_delayed_work(&npinfo->tx_work);
 837
 838                                 /* clean after last, unfinished work */
 839                                 __skb_queue_purge(&npinfo->txq);
 840                                 kfree(npinfo);
 841                                 np->dev->npinfo = NULL;
 842                         }
 843                 }
 844
 845                 dev_put(np->dev);
 846         }
 847
 848         np->dev = NULL;
 849 }
 850
 851 int netpoll_trap(void)
 852 {
 853         return atomic_read(&trapped);
 854 }
 855
 856 void netpoll_set_trap(int trap)
 857 {
 858         if (trap)
 859                 atomic_inc(&trapped);
 860         else
 861                 atomic_dec(&trapped);
 862 }
 863
 864 EXPORT_SYMBOL(netpoll_set_trap);
 865 EXPORT_SYMBOL(netpoll_trap);
 866 EXPORT_SYMBOL(netpoll_print_options);
 867 EXPORT_SYMBOL(netpoll_parse_options);
 868 EXPORT_SYMBOL(netpoll_setup);
 869 EXPORT_SYMBOL(netpoll_cleanup);
 870 EXPORT_SYMBOL(netpoll_send_udp);
 871 EXPORT_SYMBOL(netpoll_poll);