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
  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_frozen_or_stopped(txq) ||
  79                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  80                         skb_queue_head(&npinfo->txq, skb);
  81                         __netif_tx_unlock(txq);
  82                         local_irq_restore(flags);
  83
  84                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
  85                         return;
  86                 }
  87                 __netif_tx_unlock(txq);
  88                 local_irq_restore(flags);
  89         }
  90 }
  91
  92 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  93                             unsigned short ulen, __be32 saddr, __be32 daddr)
  94 {
  95         __wsum psum;
  96
  97         if (uh->check == 0 || skb_csum_unnecessary(skb))
  98                 return 0;
  99
 100         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 101
 102         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 103             !csum_fold(csum_add(psum, skb->csum)))
 104                 return 0;
 105
 106         skb->csum = psum;
 107
 108         return __skb_checksum_complete(skb);
 109 }
 110
 111 /*
 112  * Check whether delayed processing was scheduled for our NIC. If so,
 113  * we attempt to grab the poll lock and use ->poll() to pump the card.
 114  * If this fails, either we've recursed in ->poll() or it's already
 115  * running on another CPU.
 116  *
 117  * Note: we don't mask interrupts with this lock because we're using
 118  * trylock here and interrupts are already disabled in the softirq
 119  * case. Further, we test the poll_owner to avoid recursion on UP
 120  * systems where the lock doesn't exist.
 121  *
 122  * In cases where there is bi-directional communications, reading only
 123  * one message at a time can lead to packets being dropped by the
 124  * network adapter, forcing superfluous retries and possibly timeouts.
 125  * Thus, we set our budget to greater than 1.
 126  */
 127 static int poll_one_napi(struct netpoll_info *npinfo,
 128                          struct napi_struct *napi, int budget)
 129 {
 130         int work;
 131
 132         /* net_rx_action's ->poll() invocations and our's are
 133          * synchronized by this test which is only made while
 134          * holding the napi->poll_lock.
 135          */
 136         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 137                 return budget;
 138
 139         npinfo->rx_flags |= NETPOLL_RX_DROP;
 140         atomic_inc(&trapped);
 141         set_bit(NAPI_STATE_NPSVC, &napi->state);
 142
 143         work = napi->poll(napi, budget);
 144         trace_napi_poll(napi);
 145
 146         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 147         atomic_dec(&trapped);
 148         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 149
 150         return budget - work;
 151 }
 152
 153 static void poll_napi(struct net_device *dev)
 154 {
 155         struct napi_struct *napi;
 156         int budget = 16;
 157
 158         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 159                 if (napi->poll_owner != smp_processor_id() &&
 160                     spin_trylock(&napi->poll_lock)) {
 161                         budget = poll_one_napi(dev->npinfo, napi, budget);
 162                         spin_unlock(&napi->poll_lock);
 163
 164                         if (!budget)
 165                                 break;
 166                 }
 167         }
 168 }
 169
 170 static void service_arp_queue(struct netpoll_info *npi)
 171 {
 172         if (npi) {
 173                 struct sk_buff *skb;
 174
 175                 while ((skb = skb_dequeue(&npi->arp_tx)))
 176                         arp_reply(skb);
 177         }
 178 }
 179
 180 void netpoll_poll_dev(struct net_device *dev)
 181 {
 182         const struct net_device_ops *ops;
 183
 184         if (!dev || !netif_running(dev))
 185                 return;
 186
 187         ops = dev->netdev_ops;
 188         if (!ops->ndo_poll_controller)
 189                 return;
 190
 191         /* Process pending work on NIC */
 192         ops->ndo_poll_controller(dev);
 193
 194         poll_napi(dev);
 195
 196         if (dev->priv_flags & IFF_SLAVE) {
 197                 if (dev->npinfo) {
 198                         struct net_device *bond_dev = dev->master;
 199                         struct sk_buff *skb;
 200                         while ((skb = skb_dequeue(&dev->npinfo->arp_tx))) {
 201                                 skb->dev = bond_dev;
 202                                 skb_queue_tail(&bond_dev->npinfo->arp_tx, skb);
 203                         }
 204                 }
 205         }
 206
 207         service_arp_queue(dev->npinfo);
 208
 209         zap_completion_queue();
 210 }
 211 EXPORT_SYMBOL(netpoll_poll_dev);
 212
 213 void netpoll_poll(struct netpoll *np)
 214 {
 215         netpoll_poll_dev(np->dev);
 216 }
 217 EXPORT_SYMBOL(netpoll_poll);
 218
 219 static void refill_skbs(void)
 220 {
 221         struct sk_buff *skb;
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(&skb_pool.lock, flags);
 225         while (skb_pool.qlen < MAX_SKBS) {
 226                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 227                 if (!skb)
 228                         break;
 229
 230                 __skb_queue_tail(&skb_pool, skb);
 231         }
 232         spin_unlock_irqrestore(&skb_pool.lock, flags);
 233 }
 234
 235 static void zap_completion_queue(void)
 236 {
 237         unsigned long flags;
 238         struct softnet_data *sd = &get_cpu_var(softnet_data);
 239
 240         if (sd->completion_queue) {
 241                 struct sk_buff *clist;
 242
 243                 local_irq_save(flags);
 244                 clist = sd->completion_queue;
 245                 sd->completion_queue = NULL;
 246                 local_irq_restore(flags);
 247
 248                 while (clist != NULL) {
 249                         struct sk_buff *skb = clist;
 250                         clist = clist->next;
 251                         if (skb->destructor) {
 252                                 atomic_inc(&skb->users);
 253                                 dev_kfree_skb_any(skb); /* put this one back */
 254                         } else {
 255                                 __kfree_skb(skb);
 256                         }
 257                 }
 258         }
 259
 260         put_cpu_var(softnet_data);
 261 }
 262
 263 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 264 {
 265         int count = 0;
 266         struct sk_buff *skb;
 267
 268         zap_completion_queue();
 269         refill_skbs();
 270 repeat:
 271
 272         skb = alloc_skb(len, GFP_ATOMIC);
 273         if (!skb)
 274                 skb = skb_dequeue(&skb_pool);
 275
 276         if (!skb) {
 277                 if (++count < 10) {
 278                         netpoll_poll(np);
 279                         goto repeat;
 280                 }
 281                 return NULL;
 282         }
 283
 284         atomic_set(&skb->users, 1);
 285         skb_reserve(skb, reserve);
 286         return skb;
 287 }
 288
 289 static int netpoll_owner_active(struct net_device *dev)
 290 {
 291         struct napi_struct *napi;
 292
 293         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 294                 if (napi->poll_owner == smp_processor_id())
 295                         return 1;
 296         }
 297         return 0;
 298 }
 299
 300 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 301                              struct net_device *dev)
 302 {
 303         int status = NETDEV_TX_BUSY;
 304         unsigned long tries;
 305         const struct net_device_ops *ops = dev->netdev_ops;
 306         /* It is up to the caller to keep npinfo alive. */
 307         struct netpoll_info *npinfo = np->dev->npinfo;
 308
 309         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 310                 __kfree_skb(skb);
 311                 return;
 312         }
 313
 314         /* don't get messages out of order, and no recursion */
 315         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 316                 struct netdev_queue *txq;
 317                 unsigned long flags;
 318
 319                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 320
 321                 local_irq_save(flags);
 322                 /* try until next clock tick */
 323                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 324                      tries > 0; --tries) {
 325                         if (__netif_tx_trylock(txq)) {
 326                                 if (!netif_tx_queue_stopped(txq)) {
 327                                         status = ops->ndo_start_xmit(skb, dev);
 328                                         if (status == NETDEV_TX_OK)
 329                                                 txq_trans_update(txq);
 330                                 }
 331                                 __netif_tx_unlock(txq);
 332
 333                                 if (status == NETDEV_TX_OK)
 334                                         break;
 335
 336                         }
 337
 338                         /* tickle device maybe there is some cleanup */
 339                         netpoll_poll(np);
 340
 341                         udelay(USEC_PER_POLL);
 342                 }
 343
 344                 WARN_ONCE(!irqs_disabled(),
 345                         "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
 346                         dev->name, ops->ndo_start_xmit);
 347
 348                 local_irq_restore(flags);
 349         }
 350
 351         if (status != NETDEV_TX_OK) {
 352                 skb_queue_tail(&npinfo->txq, skb);
 353                 schedule_delayed_work(&npinfo->tx_work,0);
 354         }
 355 }
 356 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 357
 358 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 359 {
 360         int total_len, eth_len, ip_len, udp_len;
 361         struct sk_buff *skb;
 362         struct udphdr *udph;
 363         struct iphdr *iph;
 364         struct ethhdr *eth;
 365
 366         udp_len = len + sizeof(*udph);
 367         ip_len = eth_len = udp_len + sizeof(*iph);
 368         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
 369
 370         skb = find_skb(np, total_len, total_len - len);
 371         if (!skb)
 372                 return;
 373
 374         skb_copy_to_linear_data(skb, msg, len);
 375         skb->len += len;
 376
 377         skb_push(skb, sizeof(*udph));
 378         skb_reset_transport_header(skb);
 379         udph = udp_hdr(skb);
 380         udph->source = htons(np->local_port);
 381         udph->dest = htons(np->remote_port);
 382         udph->len = htons(udp_len);
 383         udph->check = 0;
 384         udph->check = csum_tcpudp_magic(np->local_ip,
 385                                         np->remote_ip,
 386                                         udp_len, IPPROTO_UDP,
 387                                         csum_partial(udph, udp_len, 0));
 388         if (udph->check == 0)
 389                 udph->check = CSUM_MANGLED_0;
 390
 391         skb_push(skb, sizeof(*iph));
 392         skb_reset_network_header(skb);
 393         iph = ip_hdr(skb);
 394
 395         /* iph->version = 4; iph->ihl = 5; */
 396         put_unaligned(0x45, (unsigned char *)iph);
 397         iph->tos      = 0;
 398         put_unaligned(htons(ip_len), &(iph->tot_len));
 399         iph->id       = 0;
 400         iph->frag_off = 0;
 401         iph->ttl      = 64;
 402         iph->protocol = IPPROTO_UDP;
 403         iph->check    = 0;
 404         put_unaligned(np->local_ip, &(iph->saddr));
 405         put_unaligned(np->remote_ip, &(iph->daddr));
 406         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 407
 408         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 409         skb_reset_mac_header(skb);
 410         skb->protocol = eth->h_proto = htons(ETH_P_IP);
 411         memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
 412         memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
 413
 414         skb->dev = np->dev;
 415
 416         netpoll_send_skb(np, skb);
 417 }
 418 EXPORT_SYMBOL(netpoll_send_udp);
 419
 420 static void arp_reply(struct sk_buff *skb)
 421 {
 422         struct netpoll_info *npinfo = skb->dev->npinfo;
 423         struct arphdr *arp;
 424         unsigned char *arp_ptr;
 425         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 426         __be32 sip, tip;
 427         unsigned char *sha;
 428         struct sk_buff *send_skb;
 429         struct netpoll *np, *tmp;
 430         unsigned long flags;
 431         int hits = 0;
 432
 433         if (list_empty(&npinfo->rx_np))
 434                 return;
 435
 436         /* Before checking the packet, we do some early
 437            inspection whether this is interesting at all */
 438         spin_lock_irqsave(&npinfo->rx_lock, flags);
 439         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 440                 if (np->dev == skb->dev)
 441                         hits++;
 442         }
 443         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 444
 445         /* No netpoll struct is using this dev */
 446         if (!hits)
 447                 return;
 448
 449         /* No arp on this interface */
 450         if (skb->dev->flags & IFF_NOARP)
 451                 return;
 452
 453         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 454                 return;
 455
 456         skb_reset_network_header(skb);
 457         skb_reset_transport_header(skb);
 458         arp = arp_hdr(skb);
 459
 460         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 461              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 462             arp->ar_pro != htons(ETH_P_IP) ||
 463             arp->ar_op != htons(ARPOP_REQUEST))
 464                 return;
 465
 466         arp_ptr = (unsigned char *)(arp+1);
 467         /* save the location of the src hw addr */
 468         sha = arp_ptr;
 469         arp_ptr += skb->dev->addr_len;
 470         memcpy(&sip, arp_ptr, 4);
 471         arp_ptr += 4;
 472         /* If we actually cared about dst hw addr,
 473            it would get copied here */
 474         arp_ptr += skb->dev->addr_len;
 475         memcpy(&tip, arp_ptr, 4);
 476
 477         /* Should we ignore arp? */
 478         if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 479                 return;
 480
 481         size = arp_hdr_len(skb->dev);
 482
 483         spin_lock_irqsave(&npinfo->rx_lock, flags);
 484         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 485                 if (tip != np->local_ip)
 486                         continue;
 487
 488                 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
 489                                     LL_RESERVED_SPACE(np->dev));
 490                 if (!send_skb)
 491                         continue;
 492
 493                 skb_reset_network_header(send_skb);
 494                 arp = (struct arphdr *) skb_put(send_skb, size);
 495                 send_skb->dev = skb->dev;
 496                 send_skb->protocol = htons(ETH_P_ARP);
 497
 498                 /* Fill the device header for the ARP frame */
 499                 if (dev_hard_header(send_skb, skb->dev, ptype,
 500                                     sha, np->dev->dev_addr,
 501                                     send_skb->len) < 0) {
 502                         kfree_skb(send_skb);
 503                         continue;
 504                 }
 505
 506                 /*
 507                  * Fill out the arp protocol part.
 508                  *
 509                  * we only support ethernet device type,
 510                  * which (according to RFC 1390) should
 511                  * always equal 1 (Ethernet).
 512                  */
 513
 514                 arp->ar_hrd = htons(np->dev->type);
 515                 arp->ar_pro = htons(ETH_P_IP);
 516                 arp->ar_hln = np->dev->addr_len;
 517                 arp->ar_pln = 4;
 518                 arp->ar_op = htons(type);
 519
 520                 arp_ptr = (unsigned char *)(arp + 1);
 521                 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 522                 arp_ptr += np->dev->addr_len;
 523                 memcpy(arp_ptr, &tip, 4);
 524                 arp_ptr += 4;
 525                 memcpy(arp_ptr, sha, np->dev->addr_len);
 526                 arp_ptr += np->dev->addr_len;
 527                 memcpy(arp_ptr, &sip, 4);
 528
 529                 netpoll_send_skb(np, send_skb);
 530
 531                 /* If there are several rx_hooks for the same address,
 532                    we're fine by sending a single reply */
 533                 break;
 534         }
 535         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 536 }
 537
 538 int __netpoll_rx(struct sk_buff *skb)
 539 {
 540         int proto, len, ulen;
 541         int hits = 0;
 542         const struct iphdr *iph;
 543         struct udphdr *uh;
 544         struct netpoll_info *npinfo = skb->dev->npinfo;
 545         struct netpoll *np, *tmp;
 546
 547         if (list_empty(&npinfo->rx_np))
 548                 goto out;
 549
 550         if (skb->dev->type != ARPHRD_ETHER)
 551                 goto out;
 552
 553         /* check if netpoll clients need ARP */
 554         if (skb->protocol == htons(ETH_P_ARP) &&
 555             atomic_read(&trapped)) {
 556                 skb_queue_tail(&npinfo->arp_tx, skb);
 557                 return 1;
 558         }
 559
 560         proto = ntohs(eth_hdr(skb)->h_proto);
 561         if (proto != ETH_P_IP)
 562                 goto out;
 563         if (skb->pkt_type == PACKET_OTHERHOST)
 564                 goto out;
 565         if (skb_shared(skb))
 566                 goto out;
 567
 568         iph = (struct iphdr *)skb->data;
 569         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 570                 goto out;
 571         if (iph->ihl < 5 || iph->version != 4)
 572                 goto out;
 573         if (!pskb_may_pull(skb, iph->ihl*4))
 574                 goto out;
 575         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 576                 goto out;
 577
 578         len = ntohs(iph->tot_len);
 579         if (skb->len < len || len < iph->ihl*4)
 580                 goto out;
 581
 582         /*
 583          * Our transport medium may have padded the buffer out.
 584          * Now We trim to the true length of the frame.
 585          */
 586         if (pskb_trim_rcsum(skb, len))
 587                 goto out;
 588
 589         if (iph->protocol != IPPROTO_UDP)
 590                 goto out;
 591
 592         len -= iph->ihl*4;
 593         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 594         ulen = ntohs(uh->len);
 595
 596         if (ulen != len)
 597                 goto out;
 598         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 599                 goto out;
 600
 601         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 602                 if (np->local_ip && np->local_ip != iph->daddr)
 603                         continue;
 604                 if (np->remote_ip && np->remote_ip != iph->saddr)
 605                         continue;
 606                 if (np->local_port && np->local_port != ntohs(uh->dest))
 607                         continue;
 608
 609                 np->rx_hook(np, ntohs(uh->source),
 610                                (char *)(uh+1),
 611                                ulen - sizeof(struct udphdr));
 612                 hits++;
 613         }
 614
 615         if (!hits)
 616                 goto out;
 617
 618         kfree_skb(skb);
 619         return 1;
 620
 621 out:
 622         if (atomic_read(&trapped)) {
 623                 kfree_skb(skb);
 624                 return 1;
 625         }
 626
 627         return 0;
 628 }
 629
 630 void netpoll_print_options(struct netpoll *np)
 631 {
 632         printk(KERN_INFO "%s: local port %d\n",
 633                          np->name, np->local_port);
 634         printk(KERN_INFO "%s: local IP %pI4\n",
 635                          np->name, &np->local_ip);
 636         printk(KERN_INFO "%s: interface '%s'\n",
 637                          np->name, np->dev_name);
 638         printk(KERN_INFO "%s: remote port %d\n",
 639                          np->name, np->remote_port);
 640         printk(KERN_INFO "%s: remote IP %pI4\n",
 641                          np->name, &np->remote_ip);
 642         printk(KERN_INFO "%s: remote ethernet address %pM\n",
 643                          np->name, np->remote_mac);
 644 }
 645 EXPORT_SYMBOL(netpoll_print_options);
 646
 647 int netpoll_parse_options(struct netpoll *np, char *opt)
 648 {
 649         char *cur=opt, *delim;
 650
 651         if (*cur != '@') {
 652                 if ((delim = strchr(cur, '@')) == NULL)
 653                         goto parse_failed;
 654                 *delim = 0;
 655                 np->local_port = simple_strtol(cur, NULL, 10);
 656                 cur = delim;
 657         }
 658         cur++;
 659
 660         if (*cur != '/') {
 661                 if ((delim = strchr(cur, '/')) == NULL)
 662                         goto parse_failed;
 663                 *delim = 0;
 664                 np->local_ip = in_aton(cur);
 665                 cur = delim;
 666         }
 667         cur++;
 668
 669         if (*cur != ',') {
 670                 /* parse out dev name */
 671                 if ((delim = strchr(cur, ',')) == NULL)
 672                         goto parse_failed;
 673                 *delim = 0;
 674                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 675                 cur = delim;
 676         }
 677         cur++;
 678
 679         if (*cur != '@') {
 680                 /* dst port */
 681                 if ((delim = strchr(cur, '@')) == NULL)
 682                         goto parse_failed;
 683                 *delim = 0;
 684                 if (*cur == ' ' || *cur == '\t')
 685                         printk(KERN_INFO "%s: warning: whitespace"
 686                                         "is not allowed\n", np->name);
 687                 np->remote_port = simple_strtol(cur, NULL, 10);
 688                 cur = delim;
 689         }
 690         cur++;
 691
 692         /* dst ip */
 693         if ((delim = strchr(cur, '/')) == NULL)
 694                 goto parse_failed;
 695         *delim = 0;
 696         np->remote_ip = in_aton(cur);
 697         cur = delim + 1;
 698
 699         if (*cur != 0) {
 700                 /* MAC address */
 701                 if (!mac_pton(cur, np->remote_mac))
 702                         goto parse_failed;
 703         }
 704
 705         netpoll_print_options(np);
 706
 707         return 0;
 708
 709  parse_failed:
 710         printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
 711                np->name, cur);
 712         return -1;
 713 }
 714 EXPORT_SYMBOL(netpoll_parse_options);
 715
 716 int __netpoll_setup(struct netpoll *np)
 717 {
 718         struct net_device *ndev = np->dev;
 719         struct netpoll_info *npinfo;
 720         const struct net_device_ops *ops;
 721         unsigned long flags;
 722         int err;
 723
 724         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 725             !ndev->netdev_ops->ndo_poll_controller) {
 726                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
 727                        np->name, np->dev_name);
 728                 err = -ENOTSUPP;
 729                 goto out;
 730         }
 731
 732         if (!ndev->npinfo) {
 733                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 734                 if (!npinfo) {
 735                         err = -ENOMEM;
 736                         goto out;
 737                 }
 738
 739                 npinfo->rx_flags = 0;
 740                 INIT_LIST_HEAD(&npinfo->rx_np);
 741
 742                 spin_lock_init(&npinfo->rx_lock);
 743                 skb_queue_head_init(&npinfo->arp_tx);
 744                 skb_queue_head_init(&npinfo->txq);
 745                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 746
 747                 atomic_set(&npinfo->refcnt, 1);
 748
 749                 ops = np->dev->netdev_ops;
 750                 if (ops->ndo_netpoll_setup) {
 751                         err = ops->ndo_netpoll_setup(ndev, npinfo);
 752                         if (err)
 753                                 goto free_npinfo;
 754                 }
 755         } else {
 756                 npinfo = ndev->npinfo;
 757                 atomic_inc(&npinfo->refcnt);
 758         }
 759
 760         npinfo->netpoll = np;
 761
 762         if (np->rx_hook) {
 763                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 764                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
 765                 list_add_tail(&np->rx, &npinfo->rx_np);
 766                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 767         }
 768
 769         /* last thing to do is link it to the net device structure */
 770         rcu_assign_pointer(ndev->npinfo, npinfo);
 771
 772         return 0;
 773
 774 free_npinfo:
 775         kfree(npinfo);
 776 out:
 777         return err;
 778 }
 779 EXPORT_SYMBOL_GPL(__netpoll_setup);
 780
 781 int netpoll_setup(struct netpoll *np)
 782 {
 783         struct net_device *ndev = NULL;
 784         struct in_device *in_dev;
 785         int err;
 786
 787         if (np->dev_name)
 788                 ndev = dev_get_by_name(&init_net, np->dev_name);
 789         if (!ndev) {
 790                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
 791                        np->name, np->dev_name);
 792                 return -ENODEV;
 793         }
 794
 795         if (ndev->master) {
 796                 printk(KERN_ERR "%s: %s is a slave device, aborting.\n",
 797                        np->name, np->dev_name);
 798                 err = -EBUSY;
 799                 goto put;
 800         }
 801
 802         if (!netif_running(ndev)) {
 803                 unsigned long atmost, atleast;
 804
 805                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 806                        np->name, np->dev_name);
 807
 808                 rtnl_lock();
 809                 err = dev_open(ndev);
 810                 rtnl_unlock();
 811
 812                 if (err) {
 813                         printk(KERN_ERR "%s: failed to open %s\n",
 814                                np->name, ndev->name);
 815                         goto put;
 816                 }
 817
 818                 atleast = jiffies + HZ/10;
 819                 atmost = jiffies + carrier_timeout * HZ;
 820                 while (!netif_carrier_ok(ndev)) {
 821                         if (time_after(jiffies, atmost)) {
 822                                 printk(KERN_NOTICE
 823                                        "%s: timeout waiting for carrier\n",
 824                                        np->name);
 825                                 break;
 826                         }
 827                         msleep(1);
 828                 }
 829
 830                 /* If carrier appears to come up instantly, we don't
 831                  * trust it and pause so that we don't pump all our
 832                  * queued console messages into the bitbucket.
 833                  */
 834
 835                 if (time_before(jiffies, atleast)) {
 836                         printk(KERN_NOTICE "%s: carrier detect appears"
 837                                " untrustworthy, waiting 4 seconds\n",
 838                                np->name);
 839                         msleep(4000);
 840                 }
 841         }
 842
 843         if (!np->local_ip) {
 844                 rcu_read_lock();
 845                 in_dev = __in_dev_get_rcu(ndev);
 846
 847                 if (!in_dev || !in_dev->ifa_list) {
 848                         rcu_read_unlock();
 849                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
 850                                np->name, np->dev_name);
 851                         err = -EDESTADDRREQ;
 852                         goto put;
 853                 }
 854
 855                 np->local_ip = in_dev->ifa_list->ifa_local;
 856                 rcu_read_unlock();
 857                 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
 858         }
 859
 860         np->dev = ndev;
 861
 862         /* fill up the skb queue */
 863         refill_skbs();
 864
 865         rtnl_lock();
 866         err = __netpoll_setup(np);
 867         rtnl_unlock();
 868
 869         if (err)
 870                 goto put;
 871
 872         return 0;
 873
 874 put:
 875         dev_put(ndev);
 876         return err;
 877 }
 878 EXPORT_SYMBOL(netpoll_setup);
 879
 880 static int __init netpoll_init(void)
 881 {
 882         skb_queue_head_init(&skb_pool);
 883         return 0;
 884 }
 885 core_initcall(netpoll_init);
 886
 887 void __netpoll_cleanup(struct netpoll *np)
 888 {
 889         struct netpoll_info *npinfo;
 890         unsigned long flags;
 891
 892         npinfo = np->dev->npinfo;
 893         if (!npinfo)
 894                 return;
 895
 896         if (!list_empty(&npinfo->rx_np)) {
 897                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 898                 list_del(&np->rx);
 899                 if (list_empty(&npinfo->rx_np))
 900                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
 901                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 902         }
 903
 904         if (atomic_dec_and_test(&npinfo->refcnt)) {
 905                 const struct net_device_ops *ops;
 906
 907                 ops = np->dev->netdev_ops;
 908                 if (ops->ndo_netpoll_cleanup)
 909                         ops->ndo_netpoll_cleanup(np->dev);
 910
 911                 rcu_assign_pointer(np->dev->npinfo, NULL);
 912
 913                 /* avoid racing with NAPI reading npinfo */
 914                 synchronize_rcu_bh();
 915
 916                 skb_queue_purge(&npinfo->arp_tx);
 917                 skb_queue_purge(&npinfo->txq);
 918                 cancel_delayed_work_sync(&npinfo->tx_work);
 919
 920                 /* clean after last, unfinished work */
 921                 __skb_queue_purge(&npinfo->txq);
 922                 kfree(npinfo);
 923         }
 924 }
 925 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 926
 927 void netpoll_cleanup(struct netpoll *np)
 928 {
 929         if (!np->dev)
 930                 return;
 931
 932         rtnl_lock();
 933         __netpoll_cleanup(np);
 934         rtnl_unlock();
 935
 936         dev_put(np->dev);
 937         np->dev = NULL;
 938 }
 939 EXPORT_SYMBOL(netpoll_cleanup);
 940
 941 int netpoll_trap(void)
 942 {
 943         return atomic_read(&trapped);
 944 }
 945 EXPORT_SYMBOL(netpoll_trap);
 946
 947 void netpoll_set_trap(int trap)
 948 {
 949         if (trap)
 950                 atomic_inc(&trapped);
 951         else
 952                 atomic_dec(&trapped);
 953 }
 954 EXPORT_SYMBOL(netpoll_set_trap);