netpoll.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05
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 40static struct sk_buff_head skb_pool; 41 42static 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 52static void zap_completion_queue(void); 53static void arp_reply(struct sk_buff *skb); 54 55static unsigned int carrier_timeout = 4; 56module_param(carrier_timeout, uint, 0644); 57 58static void queue_process(struct work_struct *work) 59{ 60 struct netpoll_info *npinfo = 61 container_of(work, struct netpoll_info, tx_work.work); 62 struct sk_buff *skb; 63 unsigned long flags; 64 65 while ((skb = skb_dequeue(&npinfo->txq))) { 66 struct net_device *dev = skb->dev; 67 const struct net_device_ops *ops = dev->netdev_ops; 68 struct netdev_queue *txq; 69 70 if (!netif_device_present(dev) || !netif_running(dev)) { 71 __kfree_skb(skb); 72 continue; 73 } 74 75 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb)); 76 77 local_irq_save(flags); 78 __netif_tx_lock(txq, smp_processor_id()); 79 if (netif_tx_queue_stopped(txq) || 80 netif_tx_queue_frozen(txq) || 81 ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) { 82 skb_queue_head(&npinfo->txq, skb); 83 __netif_tx_unlock(txq); 84 local_irq_restore(flags); 85 86 schedule_delayed_work(&npinfo->tx_work, HZ/10); 87 return; 88 } 89 __netif_tx_unlock(txq); 90 local_irq_restore(flags); 91 } 92} 93 94static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh, 95 unsigned short ulen, __be32 saddr, __be32 daddr) 96{ 97 __wsum psum; 98 99 if (uh->check == 0 || skb_csum_unnecessary(skb)) 100 return 0; 101 102 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0); 103 104 if (skb->ip_summed == CHECKSUM_COMPLETE && 105 !csum_fold(csum_add(psum, skb->csum))) 106 return 0; 107 108 skb->csum = psum; 109 110 return __skb_checksum_complete(skb); 111} 112 113/* 114 * Check whether delayed processing was scheduled for our NIC. If so, 115 * we attempt to grab the poll lock and use ->poll() to pump the card. 116 * If this fails, either we've recursed in ->poll() or it's already 117 * running on another CPU. 118 * 119 * Note: we don't mask interrupts with this lock because we're using 120 * trylock here and interrupts are already disabled in the softirq 121 * case. Further, we test the poll_owner to avoid recursion on UP 122 * systems where the lock doesn't exist. 123 * 124 * In cases where there is bi-directional communications, reading only 125 * one message at a time can lead to packets being dropped by the 126 * network adapter, forcing superfluous retries and possibly timeouts. 127 * Thus, we set our budget to greater than 1. 128 */ 129static int poll_one_napi(struct netpoll_info *npinfo, 130 struct napi_struct *napi, int budget) 131{ 132 int work; 133 134 /* net_rx_action's ->poll() invocations and our's are 135 * synchronized by this test which is only made while 136 * holding the napi->poll_lock. 137 */ 138 if (!test_bit(NAPI_STATE_SCHED, &napi->state)) 139 return budget; 140 141 npinfo->rx_flags |= NETPOLL_RX_DROP; 142 atomic_inc(&trapped); 143 set_bit(NAPI_STATE_NPSVC, &napi->state); 144 145 work = napi->poll(napi, budget); 146 trace_napi_poll(napi); 147 148 clear_bit(NAPI_STATE_NPSVC, &napi->state); 149 atomic_dec(&trapped); 150 npinfo->rx_flags &= ~NETPOLL_RX_DROP; 151 152 return budget - work; 153} 154 155static void poll_napi(struct net_device *dev) 156{ 157 struct napi_struct *napi; 158 int budget = 16; 159 160 list_for_each_entry(napi, &dev->napi_list, dev_list) { 161 if (napi->poll_owner != smp_processor_id() && 162 spin_trylock(&napi->poll_lock)) { 163 budget = poll_one_napi(dev->npinfo, napi, budget); 164 spin_unlock(&napi->poll_lock); 165 166 if (!budget) 167 break; 168 } 169 } 170} 171 172static void service_arp_queue(struct netpoll_info *npi) 173{ 174 if (npi) { 175 struct sk_buff *skb; 176 177 while ((skb = skb_dequeue(&npi->arp_tx))) 178 arp_reply(skb); 179 } 180} 181 182void netpoll_poll(struct netpoll *np) 183{ 184 struct net_device *dev = np->dev; 185 const struct net_device_ops *ops; 186 187 if (!dev || !netif_running(dev)) 188 return; 189 190 ops = dev->netdev_ops; 191 if (!ops->ndo_poll_controller) 192 return; 193 194 /* Process pending work on NIC */ 195 ops->ndo_poll_controller(dev); 196 197 poll_napi(dev); 198 199 service_arp_queue(dev->npinfo); 200 201 zap_completion_queue(); 202} 203 204static void refill_skbs(void) 205{ 206 struct sk_buff *skb; 207 unsigned long flags; 208 209 spin_lock_irqsave(&skb_pool.lock, flags); 210 while (skb_pool.qlen < MAX_SKBS) { 211 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC); 212 if (!skb) 213 break; 214 215 __skb_queue_tail(&skb_pool, skb); 216 } 217 spin_unlock_irqrestore(&skb_pool.lock, flags); 218} 219 220static void zap_completion_queue(void) 221{ 222 unsigned long flags; 223 struct softnet_data *sd = &get_cpu_var(softnet_data); 224 225 if (sd->completion_queue) { 226 struct sk_buff *clist; 227 228 local_irq_save(flags); 229 clist = sd->completion_queue; 230 sd->completion_queue = NULL; 231 local_irq_restore(flags); 232 233 while (clist != NULL) { 234 struct sk_buff *skb = clist; 235 clist = clist->next; 236 if (skb->destructor) { 237 atomic_inc(&skb->users); 238 dev_kfree_skb_any(skb); /* put this one back */ 239 } else { 240 __kfree_skb(skb); 241 } 242 } 243 } 244 245 put_cpu_var(softnet_data); 246} 247 248static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve) 249{ 250 int count = 0; 251 struct sk_buff *skb; 252 253 zap_completion_queue(); 254 refill_skbs(); 255repeat: 256 257 skb = alloc_skb(len, GFP_ATOMIC); 258 if (!skb) 259 skb = skb_dequeue(&skb_pool); 260 261 if (!skb) { 262 if (++count < 10) { 263 netpoll_poll(np); 264 goto repeat; 265 } 266 return NULL; 267 } 268 269 atomic_set(&skb->users, 1); 270 skb_reserve(skb, reserve); 271 return skb; 272} 273 274static int netpoll_owner_active(struct net_device *dev) 275{ 276 struct napi_struct *napi; 277 278 list_for_each_entry(napi, &dev->napi_list, dev_list) { 279 if (napi->poll_owner == smp_processor_id()) 280 return 1; 281 } 282 return 0; 283} 284 285static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 286{ 287 int status = NETDEV_TX_BUSY; 288 unsigned long tries; 289 struct net_device *dev = np->dev; 290 const struct net_device_ops *ops = dev->netdev_ops; 291 struct netpoll_info *npinfo = np->dev->npinfo; 292 293 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { 294 __kfree_skb(skb); 295 return; 296 } 297 298 /* don't get messages out of order, and no recursion */ 299 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) { 300 struct netdev_queue *txq; 301 unsigned long flags; 302 303 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb)); 304 305 local_irq_save(flags); 306 /* try until next clock tick */ 307 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; 308 tries > 0; --tries) { 309 if (__netif_tx_trylock(txq)) { 310 if (!netif_tx_queue_stopped(txq)) { 311 status = ops->ndo_start_xmit(skb, dev); 312 if (status == NETDEV_TX_OK) 313 txq_trans_update(txq); 314 } 315 __netif_tx_unlock(txq); 316 317 if (status == NETDEV_TX_OK) 318 break; 319 320 } 321 322 /* tickle device maybe there is some cleanup */ 323 netpoll_poll(np); 324 325 udelay(USEC_PER_POLL); 326 } 327 328 WARN_ONCE(!irqs_disabled(), 329 "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n", 330 dev->name, ops->ndo_start_xmit); 331 332 local_irq_restore(flags); 333 } 334 335 if (status != NETDEV_TX_OK) { 336 skb_queue_tail(&npinfo->txq, skb); 337 schedule_delayed_work(&npinfo->tx_work,0); 338 } 339} 340 341void netpoll_send_udp(struct netpoll *np, const char *msg, int len) 342{ 343 int total_len, eth_len, ip_len, udp_len; 344 struct sk_buff *skb; 345 struct udphdr *udph; 346 struct iphdr *iph; 347 struct ethhdr *eth; 348 349 udp_len = len + sizeof(*udph); 350 ip_len = eth_len = udp_len + sizeof(*iph); 351 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; 352 353 skb = find_skb(np, total_len, total_len - len); 354 if (!skb) 355 return; 356 357 skb_copy_to_linear_data(skb, msg, len); 358 skb->len += len; 359 360 skb_push(skb, sizeof(*udph)); 361 skb_reset_transport_header(skb); 362 udph = udp_hdr(skb); 363 udph->source = htons(np->local_port); 364 udph->dest = htons(np->remote_port); 365 udph->len = htons(udp_len); 366 udph->check = 0; 367 udph->check = csum_tcpudp_magic(np->local_ip, 368 np->remote_ip, 369 udp_len, IPPROTO_UDP, 370 csum_partial(udph, udp_len, 0)); 371 if (udph->check == 0) 372 udph->check = CSUM_MANGLED_0; 373 374 skb_push(skb, sizeof(*iph)); 375 skb_reset_network_header(skb); 376 iph = ip_hdr(skb); 377 378 /* iph->version = 4; iph->ihl = 5; */ 379 put_unaligned(0x45, (unsigned char *)iph); 380 iph->tos = 0; 381 put_unaligned(htons(ip_len), &(iph->tot_len)); 382 iph->id = 0; 383 iph->frag_off = 0; 384 iph->ttl = 64; 385 iph->protocol = IPPROTO_UDP; 386 iph->check = 0; 387 put_unaligned(np->local_ip, &(iph->saddr)); 388 put_unaligned(np->remote_ip, &(iph->daddr)); 389 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 390 391 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN); 392 skb_reset_mac_header(skb); 393 skb->protocol = eth->h_proto = htons(ETH_P_IP); 394 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN); 395 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN); 396 397 skb->dev = np->dev; 398 399 netpoll_send_skb(np, skb); 400} 401 402static void arp_reply(struct sk_buff *skb) 403{ 404 struct netpoll_info *npinfo = skb->dev->npinfo; 405 struct arphdr *arp; 406 unsigned char *arp_ptr; 407 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP; 408 __be32 sip, tip; 409 unsigned char *sha; 410 struct sk_buff *send_skb; 411 struct netpoll *np, *tmp; 412 unsigned long flags; 413 int hits = 0; 414 415 if (list_empty(&npinfo->rx_np)) 416 return; 417 418 /* Before checking the packet, we do some early 419 inspection whether this is interesting at all */ 420 spin_lock_irqsave(&npinfo->rx_lock, flags); 421 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) { 422 if (np->dev == skb->dev) 423 hits++; 424 } 425 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 426 427 /* No netpoll struct is using this dev */ 428 if (!hits) 429 return; 430 431 /* No arp on this interface */ 432 if (skb->dev->flags & IFF_NOARP) 433 return; 434 435 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) 436 return; 437 438 skb_reset_network_header(skb); 439 skb_reset_transport_header(skb); 440 arp = arp_hdr(skb); 441 442 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 443 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 444 arp->ar_pro != htons(ETH_P_IP) || 445 arp->ar_op != htons(ARPOP_REQUEST)) 446 return; 447 448 arp_ptr = (unsigned char *)(arp+1); 449 /* save the location of the src hw addr */ 450 sha = arp_ptr; 451 arp_ptr += skb->dev->addr_len; 452 memcpy(&sip, arp_ptr, 4); 453 arp_ptr += 4; 454 /* If we actually cared about dst hw addr, 455 it would get copied here */ 456 arp_ptr += skb->dev->addr_len; 457 memcpy(&tip, arp_ptr, 4); 458 459 /* Should we ignore arp? */ 460 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip)) 461 return; 462 463 size = arp_hdr_len(skb->dev); 464 465 spin_lock_irqsave(&npinfo->rx_lock, flags); 466 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) { 467 if (tip != np->local_ip) 468 continue; 469 470 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev), 471 LL_RESERVED_SPACE(np->dev)); 472 if (!send_skb) 473 continue; 474 475 skb_reset_network_header(send_skb); 476 arp = (struct arphdr *) skb_put(send_skb, size); 477 send_skb->dev = skb->dev; 478 send_skb->protocol = htons(ETH_P_ARP); 479 480 /* Fill the device header for the ARP frame */ 481 if (dev_hard_header(send_skb, skb->dev, ptype, 482 sha, np->dev->dev_addr, 483 send_skb->len) < 0) { 484 kfree_skb(send_skb); 485 continue; 486 } 487 488 /* 489 * Fill out the arp protocol part. 490 * 491 * we only support ethernet device type, 492 * which (according to RFC 1390) should 493 * always equal 1 (Ethernet). 494 */ 495 496 arp->ar_hrd = htons(np->dev->type); 497 arp->ar_pro = htons(ETH_P_IP); 498 arp->ar_hln = np->dev->addr_len; 499 arp->ar_pln = 4; 500 arp->ar_op = htons(type); 501 502 arp_ptr = (unsigned char *)(arp + 1); 503 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len); 504 arp_ptr += np->dev->addr_len; 505 memcpy(arp_ptr, &tip, 4); 506 arp_ptr += 4; 507 memcpy(arp_ptr, sha, np->dev->addr_len); 508 arp_ptr += np->dev->addr_len; 509 memcpy(arp_ptr, &sip, 4); 510 511 netpoll_send_skb(np, send_skb); 512 513 /* If there are several rx_hooks for the same address, 514 we're fine by sending a single reply */ 515 break; 516 } 517 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 518} 519 520int __netpoll_rx(struct sk_buff *skb) 521{ 522 int proto, len, ulen; 523 int hits = 0; 524 struct iphdr *iph; 525 struct udphdr *uh; 526 struct netpoll_info *npinfo = skb->dev->npinfo; 527 struct netpoll *np, *tmp; 528 529 if (list_empty(&npinfo->rx_np)) 530 goto out; 531 532 if (skb->dev->type != ARPHRD_ETHER) 533 goto out; 534 535 /* check if netpoll clients need ARP */ 536 if (skb->protocol == htons(ETH_P_ARP) && 537 atomic_read(&trapped)) { 538 skb_queue_tail(&npinfo->arp_tx, skb); 539 return 1; 540 } 541 542 proto = ntohs(eth_hdr(skb)->h_proto); 543 if (proto != ETH_P_IP) 544 goto out; 545 if (skb->pkt_type == PACKET_OTHERHOST) 546 goto out; 547 if (skb_shared(skb)) 548 goto out; 549 550 iph = (struct iphdr *)skb->data; 551 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 552 goto out; 553 if (iph->ihl < 5 || iph->version != 4) 554 goto out; 555 if (!pskb_may_pull(skb, iph->ihl*4)) 556 goto out; 557 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0) 558 goto out; 559 560 len = ntohs(iph->tot_len); 561 if (skb->len < len || len < iph->ihl*4) 562 goto out; 563 564 /* 565 * Our transport medium may have padded the buffer out. 566 * Now We trim to the true length of the frame. 567 */ 568 if (pskb_trim_rcsum(skb, len)) 569 goto out; 570 571 if (iph->protocol != IPPROTO_UDP) 572 goto out; 573 574 len -= iph->ihl*4; 575 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4); 576 ulen = ntohs(uh->len); 577 578 if (ulen != len) 579 goto out; 580 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr)) 581 goto out; 582 583 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) { 584 if (np->local_ip && np->local_ip != iph->daddr) 585 continue; 586 if (np->remote_ip && np->remote_ip != iph->saddr) 587 continue; 588 if (np->local_port && np->local_port != ntohs(uh->dest)) 589 continue; 590 591 np->rx_hook(np, ntohs(uh->source), 592 (char *)(uh+1), 593 ulen - sizeof(struct udphdr)); 594 hits++; 595 } 596 597 if (!hits) 598 goto out; 599 600 kfree_skb(skb); 601 return 1; 602 603out: 604 if (atomic_read(&trapped)) { 605 kfree_skb(skb); 606 return 1; 607 } 608 609 return 0; 610} 611 612void netpoll_print_options(struct netpoll *np) 613{ 614 printk(KERN_INFO "%s: local port %d\n", 615 np->name, np->local_port); 616 printk(KERN_INFO "%s: local IP %pI4\n", 617 np->name, &np->local_ip); 618 printk(KERN_INFO "%s: interface '%s'\n", 619 np->name, np->dev_name); 620 printk(KERN_INFO "%s: remote port %d\n", 621 np->name, np->remote_port); 622 printk(KERN_INFO "%s: remote IP %pI4\n", 623 np->name, &np->remote_ip); 624 printk(KERN_INFO "%s: remote ethernet address %pM\n", 625 np->name, np->remote_mac); 626} 627 628int netpoll_parse_options(struct netpoll *np, char *opt) 629{ 630 char *cur=opt, *delim; 631 632 if (*cur != '@') { 633 if ((delim = strchr(cur, '@')) == NULL) 634 goto parse_failed; 635 *delim = 0; 636 np->local_port = simple_strtol(cur, NULL, 10); 637 cur = delim; 638 } 639 cur++; 640 641 if (*cur != '/') { 642 if ((delim = strchr(cur, '/')) == NULL) 643 goto parse_failed; 644 *delim = 0; 645 np->local_ip = in_aton(cur); 646 cur = delim; 647 } 648 cur++; 649 650 if (*cur != ',') { 651 /* parse out dev name */ 652 if ((delim = strchr(cur, ',')) == NULL) 653 goto parse_failed; 654 *delim = 0; 655 strlcpy(np->dev_name, cur, sizeof(np->dev_name)); 656 cur = delim; 657 } 658 cur++; 659 660 if (*cur != '@') { 661 /* dst port */ 662 if ((delim = strchr(cur, '@')) == NULL) 663 goto parse_failed; 664 *delim = 0; 665 if (*cur == ' ' || *cur == '\t') 666 printk(KERN_INFO "%s: warning: whitespace" 667 "is not allowed\n", np->name); 668 np->remote_port = simple_strtol(cur, NULL, 10); 669 cur = delim; 670 } 671 cur++; 672 673 /* dst ip */ 674 if ((delim = strchr(cur, '/')) == NULL) 675 goto parse_failed; 676 *delim = 0; 677 np->remote_ip = in_aton(cur); 678 cur = delim + 1; 679 680 if (*cur != 0) { 681 /* MAC address */ 682 if ((delim = strchr(cur, ':')) == NULL) 683 goto parse_failed; 684 *delim = 0; 685 np->remote_mac[0] = simple_strtol(cur, NULL, 16); 686 cur = delim + 1; 687 if ((delim = strchr(cur, ':')) == NULL) 688 goto parse_failed; 689 *delim = 0; 690 np->remote_mac[1] = simple_strtol(cur, NULL, 16); 691 cur = delim + 1; 692 if ((delim = strchr(cur, ':')) == NULL) 693 goto parse_failed; 694 *delim = 0; 695 np->remote_mac[2] = simple_strtol(cur, NULL, 16); 696 cur = delim + 1; 697 if ((delim = strchr(cur, ':')) == NULL) 698 goto parse_failed; 699 *delim = 0; 700 np->remote_mac[3] = simple_strtol(cur, NULL, 16); 701 cur = delim + 1; 702 if ((delim = strchr(cur, ':')) == NULL) 703 goto parse_failed; 704 *delim = 0; 705 np->remote_mac[4] = simple_strtol(cur, NULL, 16); 706 cur = delim + 1; 707 np->remote_mac[5] = simple_strtol(cur, NULL, 16); 708 } 709 710 netpoll_print_options(np); 711 712 return 0; 713 714 parse_failed: 715 printk(KERN_INFO "%s: couldn't parse config at '%s'!\n", 716 np->name, cur); 717 return -1; 718} 719 720int netpoll_setup(struct netpoll *np) 721{ 722 struct net_device *ndev = NULL; 723 struct in_device *in_dev; 724 struct netpoll_info *npinfo; 725 struct netpoll *npe, *tmp; 726 unsigned long flags; 727 int err; 728 729 if (np->dev_name) 730 ndev = dev_get_by_name(&init_net, np->dev_name); 731 if (!ndev) { 732 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n", 733 np->name, np->dev_name); 734 return -ENODEV; 735 } 736 737 np->dev = ndev; 738 if (!ndev->npinfo) { 739 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); 740 if (!npinfo) { 741 err = -ENOMEM; 742 goto put; 743 } 744 745 npinfo->rx_flags = 0; 746 INIT_LIST_HEAD(&npinfo->rx_np); 747 748 spin_lock_init(&npinfo->rx_lock); 749 skb_queue_head_init(&npinfo->arp_tx); 750 skb_queue_head_init(&npinfo->txq); 751 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process); 752 753 atomic_set(&npinfo->refcnt, 1); 754 } else { 755 npinfo = ndev->npinfo; 756 atomic_inc(&npinfo->refcnt); 757 } 758 759 if (!ndev->netdev_ops->ndo_poll_controller) { 760 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n", 761 np->name, np->dev_name); 762 err = -ENOTSUPP; 763 goto release; 764 } 765 766 if (!netif_running(ndev)) { 767 unsigned long atmost, atleast; 768 769 printk(KERN_INFO "%s: device %s not up yet, forcing it\n", 770 np->name, np->dev_name); 771 772 rtnl_lock(); 773 err = dev_open(ndev); 774 rtnl_unlock(); 775 776 if (err) { 777 printk(KERN_ERR "%s: failed to open %s\n", 778 np->name, ndev->name); 779 goto release; 780 } 781 782 atleast = jiffies + HZ/10; 783 atmost = jiffies + carrier_timeout * HZ; 784 while (!netif_carrier_ok(ndev)) { 785 if (time_after(jiffies, atmost)) { 786 printk(KERN_NOTICE 787 "%s: timeout waiting for carrier\n", 788 np->name); 789 break; 790 } 791 msleep(1); 792 } 793 794 /* If carrier appears to come up instantly, we don't 795 * trust it and pause so that we don't pump all our 796 * queued console messages into the bitbucket. 797 */ 798 799 if (time_before(jiffies, atleast)) { 800 printk(KERN_NOTICE "%s: carrier detect appears" 801 " untrustworthy, waiting 4 seconds\n", 802 np->name); 803 msleep(4000); 804 } 805 } 806 807 if (!np->local_ip) { 808 rcu_read_lock(); 809 in_dev = __in_dev_get_rcu(ndev); 810 811 if (!in_dev || !in_dev->ifa_list) { 812 rcu_read_unlock(); 813 printk(KERN_ERR "%s: no IP address for %s, aborting\n", 814 np->name, np->dev_name); 815 err = -EDESTADDRREQ; 816 goto release; 817 } 818 819 np->local_ip = in_dev->ifa_list->ifa_local; 820 rcu_read_unlock(); 821 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip); 822 } 823 824 if (np->rx_hook) { 825 spin_lock_irqsave(&npinfo->rx_lock, flags); 826 npinfo->rx_flags |= NETPOLL_RX_ENABLED; 827 list_add_tail(&np->rx, &npinfo->rx_np); 828 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 829 } 830 831 /* fill up the skb queue */ 832 refill_skbs(); 833 834 /* last thing to do is link it to the net device structure */ 835 ndev->npinfo = npinfo; 836 837 /* avoid racing with NAPI reading npinfo */ 838 synchronize_rcu(); 839 840 return 0; 841 842 release: 843 if (!ndev->npinfo) { 844 spin_lock_irqsave(&npinfo->rx_lock, flags); 845 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) { 846 npe->dev = NULL; 847 } 848 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 849 850 kfree(npinfo); 851 } 852put: 853 dev_put(ndev); 854 return err; 855} 856 857static int __init netpoll_init(void) 858{ 859 skb_queue_head_init(&skb_pool); 860 return 0; 861} 862core_initcall(netpoll_init); 863 864void netpoll_cleanup(struct netpoll *np) 865{ 866 struct netpoll_info *npinfo; 867 unsigned long flags; 868 869 if (np->dev) { 870 npinfo = np->dev->npinfo; 871 if (npinfo) { 872 if (!list_empty(&npinfo->rx_np)) { 873 spin_lock_irqsave(&npinfo->rx_lock, flags); 874 list_del(&np->rx); 875 if (list_empty(&npinfo->rx_np)) 876 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED; 877 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 878 } 879 880 if (atomic_dec_and_test(&npinfo->refcnt)) { 881 skb_queue_purge(&npinfo->arp_tx); 882 skb_queue_purge(&npinfo->txq); 883 cancel_rearming_delayed_work(&npinfo->tx_work); 884 885 /* clean after last, unfinished work */ 886 __skb_queue_purge(&npinfo->txq); 887 kfree(npinfo); 888 np->dev->npinfo = NULL; 889 } 890 } 891 892 dev_put(np->dev); 893 } 894 895 np->dev = NULL; 896} 897 898int netpoll_trap(void) 899{ 900 return atomic_read(&trapped); 901} 902 903void netpoll_set_trap(int trap) 904{ 905 if (trap) 906 atomic_inc(&trapped); 907 else 908 atomic_dec(&trapped); 909} 910 911EXPORT_SYMBOL(netpoll_set_trap); 912EXPORT_SYMBOL(netpoll_trap); 913EXPORT_SYMBOL(netpoll_print_options); 914EXPORT_SYMBOL(netpoll_parse_options); 915EXPORT_SYMBOL(netpoll_setup); 916EXPORT_SYMBOL(netpoll_cleanup); 917EXPORT_SYMBOL(netpoll_send_udp); 918EXPORT_SYMBOL(netpoll_poll); 919