2 * Common framework for low-level network console, dump, and debugger code
4 * Sep 8 2003 Matt Mackall <mpm@selenic.com>
6 * based on the netconsole code from:
8 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
9 * Copyright (C) 2002 Red Hat, Inc.
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>
27 #include <asm/unaligned.h>
28 #include <trace/events/napi.h>
31 * We maintain a small pool of fully-sized skbs, to make sure the
32 * message gets out even in extreme OOM situations.
35 #define MAX_UDP_CHUNK 1460
37 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
39 static struct sk_buff_head skb_pool;
41 static atomic_t trapped;
43 #define USEC_PER_POLL 50
44 #define NETPOLL_RX_ENABLED 1
45 #define NETPOLL_RX_DROP 2
47 #define MAX_SKB_SIZE \
48 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
49 sizeof(struct iphdr) + sizeof(struct ethhdr))
51 static void zap_completion_queue(void);
52 static void arp_reply(struct sk_buff *skb);
54 static unsigned int carrier_timeout = 4;
55 module_param(carrier_timeout, uint, 0644);
57 static void queue_process(struct work_struct *work)
59 struct netpoll_info *npinfo =
60 container_of(work, struct netpoll_info, tx_work.work);
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;
69 if (!netif_device_present(dev) || !netif_running(dev)) {
74 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
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);
85 schedule_delayed_work(&npinfo->tx_work, HZ/10);
88 __netif_tx_unlock(txq);
89 local_irq_restore(flags);
93 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
94 unsigned short ulen, __be32 saddr, __be32 daddr)
98 if (uh->check == 0 || skb_csum_unnecessary(skb))
101 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
103 if (skb->ip_summed == CHECKSUM_COMPLETE &&
104 !csum_fold(csum_add(psum, skb->csum)))
109 return __skb_checksum_complete(skb);
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.
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.
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.
128 static int poll_one_napi(struct netpoll_info *npinfo,
129 struct napi_struct *napi, int budget)
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.
137 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
140 npinfo->rx_flags |= NETPOLL_RX_DROP;
141 atomic_inc(&trapped);
142 set_bit(NAPI_STATE_NPSVC, &napi->state);
144 work = napi->poll(napi, budget);
145 trace_napi_poll(napi);
147 clear_bit(NAPI_STATE_NPSVC, &napi->state);
148 atomic_dec(&trapped);
149 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
151 return budget - work;
154 static void poll_napi(struct net_device *dev)
156 struct napi_struct *napi;
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);
171 static void service_arp_queue(struct netpoll_info *npi)
176 while ((skb = skb_dequeue(&npi->arp_tx)))
181 void netpoll_poll(struct netpoll *np)
183 struct net_device *dev = np->dev;
184 const struct net_device_ops *ops;
186 if (!dev || !netif_running(dev))
189 ops = dev->netdev_ops;
190 if (!ops->ndo_poll_controller)
193 /* Process pending work on NIC */
194 ops->ndo_poll_controller(dev);
198 service_arp_queue(dev->npinfo);
200 zap_completion_queue();
203 static void refill_skbs(void)
208 spin_lock_irqsave(&skb_pool.lock, flags);
209 while (skb_pool.qlen < MAX_SKBS) {
210 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
214 __skb_queue_tail(&skb_pool, skb);
216 spin_unlock_irqrestore(&skb_pool.lock, flags);
219 static void zap_completion_queue(void)
222 struct softnet_data *sd = &get_cpu_var(softnet_data);
224 if (sd->completion_queue) {
225 struct sk_buff *clist;
227 local_irq_save(flags);
228 clist = sd->completion_queue;
229 sd->completion_queue = NULL;
230 local_irq_restore(flags);
232 while (clist != NULL) {
233 struct sk_buff *skb = clist;
235 if (skb->destructor) {
236 atomic_inc(&skb->users);
237 dev_kfree_skb_any(skb); /* put this one back */
244 put_cpu_var(softnet_data);
247 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
252 zap_completion_queue();
256 skb = alloc_skb(len, GFP_ATOMIC);
258 skb = skb_dequeue(&skb_pool);
268 atomic_set(&skb->users, 1);
269 skb_reserve(skb, reserve);
273 static int netpoll_owner_active(struct net_device *dev)
275 struct napi_struct *napi;
277 list_for_each_entry(napi, &dev->napi_list, dev_list) {
278 if (napi->poll_owner == smp_processor_id())
284 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
286 int status = NETDEV_TX_BUSY;
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;
292 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
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;
302 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
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);
314 __netif_tx_unlock(txq);
316 if (status == NETDEV_TX_OK)
321 /* tickle device maybe there is some cleanup */
324 udelay(USEC_PER_POLL);
327 WARN_ONCE(!irqs_disabled(),
328 "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
329 dev->name, ops->ndo_start_xmit);
331 local_irq_restore(flags);
334 if (status != NETDEV_TX_OK) {
335 skb_queue_tail(&npinfo->txq, skb);
336 schedule_delayed_work(&npinfo->tx_work,0);
340 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
342 int total_len, eth_len, ip_len, udp_len;
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;
352 skb = find_skb(np, total_len, total_len - len);
356 skb_copy_to_linear_data(skb, msg, len);
359 skb_push(skb, sizeof(*udph));
360 skb_reset_transport_header(skb);
362 udph->source = htons(np->local_port);
363 udph->dest = htons(np->remote_port);
364 udph->len = htons(udp_len);
366 udph->check = csum_tcpudp_magic(np->local_ip,
368 udp_len, IPPROTO_UDP,
369 csum_partial(udph, udp_len, 0));
370 if (udph->check == 0)
371 udph->check = CSUM_MANGLED_0;
373 skb_push(skb, sizeof(*iph));
374 skb_reset_network_header(skb);
377 /* iph->version = 4; iph->ihl = 5; */
378 put_unaligned(0x45, (unsigned char *)iph);
380 put_unaligned(htons(ip_len), &(iph->tot_len));
384 iph->protocol = IPPROTO_UDP;
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);
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);
398 netpoll_send_skb(np, skb);
401 static void arp_reply(struct sk_buff *skb)
403 struct netpoll_info *npinfo = skb->dev->npinfo;
405 unsigned char *arp_ptr;
406 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
409 struct sk_buff *send_skb;
410 struct netpoll *np = NULL;
412 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
417 /* No arp on this interface */
418 if (skb->dev->flags & IFF_NOARP)
421 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
424 skb_reset_network_header(skb);
425 skb_reset_transport_header(skb);
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))
434 arp_ptr = (unsigned char *)(arp+1);
435 /* save the location of the src hw addr */
437 arp_ptr += skb->dev->addr_len;
438 memcpy(&sip, 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);
444 /* Should we ignore arp? */
445 if (tip != np->local_ip ||
446 ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
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));
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);
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) {
470 * Fill out the arp protocol part.
472 * we only support ethernet device type,
473 * which (according to RFC 1390) should always equal 1 (Ethernet).
476 arp->ar_hrd = htons(np->dev->type);
477 arp->ar_pro = htons(ETH_P_IP);
478 arp->ar_hln = np->dev->addr_len;
480 arp->ar_op = htons(type);
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);
487 memcpy(arp_ptr, sha, np->dev->addr_len);
488 arp_ptr += np->dev->addr_len;
489 memcpy(arp_ptr, &sip, 4);
491 netpoll_send_skb(np, send_skb);
494 int __netpoll_rx(struct sk_buff *skb)
496 int proto, len, ulen;
499 struct netpoll_info *npi = skb->dev->npinfo;
500 struct netpoll *np = npi->rx_np;
504 if (skb->dev->type != ARPHRD_ETHER)
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);
514 proto = ntohs(eth_hdr(skb)->h_proto);
515 if (proto != ETH_P_IP)
517 if (skb->pkt_type == PACKET_OTHERHOST)
522 iph = (struct iphdr *)skb->data;
523 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
525 if (iph->ihl < 5 || iph->version != 4)
527 if (!pskb_may_pull(skb, iph->ihl*4))
529 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
532 len = ntohs(iph->tot_len);
533 if (skb->len < len || len < iph->ihl*4)
537 * Our transport medium may have padded the buffer out.
538 * Now We trim to the true length of the frame.
540 if (pskb_trim_rcsum(skb, len))
543 if (iph->protocol != IPPROTO_UDP)
547 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
548 ulen = ntohs(uh->len);
552 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
554 if (np->local_ip && np->local_ip != iph->daddr)
556 if (np->remote_ip && np->remote_ip != iph->saddr)
558 if (np->local_port && np->local_port != ntohs(uh->dest))
561 np->rx_hook(np, ntohs(uh->source),
563 ulen - sizeof(struct udphdr));
569 if (atomic_read(&trapped)) {
577 void netpoll_print_options(struct netpoll *np)
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);
593 int netpoll_parse_options(struct netpoll *np, char *opt)
595 char *cur=opt, *delim;
598 if ((delim = strchr(cur, '@')) == NULL)
601 np->local_port = simple_strtol(cur, NULL, 10);
607 if ((delim = strchr(cur, '/')) == NULL)
610 np->local_ip = in_aton(cur);
616 /* parse out dev name */
617 if ((delim = strchr(cur, ',')) == NULL)
620 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
627 if ((delim = strchr(cur, '@')) == NULL)
630 np->remote_port = simple_strtol(cur, NULL, 10);
636 if ((delim = strchr(cur, '/')) == NULL)
639 np->remote_ip = in_aton(cur);
644 if ((delim = strchr(cur, ':')) == NULL)
647 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
649 if ((delim = strchr(cur, ':')) == NULL)
652 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
654 if ((delim = strchr(cur, ':')) == NULL)
657 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
659 if ((delim = strchr(cur, ':')) == NULL)
662 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
664 if ((delim = strchr(cur, ':')) == NULL)
667 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
669 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
672 netpoll_print_options(np);
677 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
682 int netpoll_setup(struct netpoll *np)
684 struct net_device *ndev = NULL;
685 struct in_device *in_dev;
686 struct netpoll_info *npinfo;
691 ndev = dev_get_by_name(&init_net, np->dev_name);
693 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
694 np->name, np->dev_name);
700 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
706 npinfo->rx_flags = 0;
707 npinfo->rx_np = NULL;
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);
714 atomic_set(&npinfo->refcnt, 1);
716 npinfo = ndev->npinfo;
717 atomic_inc(&npinfo->refcnt);
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);
727 if (!netif_running(ndev)) {
728 unsigned long atmost, atleast;
730 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
731 np->name, np->dev_name);
734 err = dev_open(ndev);
738 printk(KERN_ERR "%s: failed to open %s\n",
739 np->name, ndev->name);
743 atleast = jiffies + HZ/10;
744 atmost = jiffies + carrier_timeout * HZ;
745 while (!netif_carrier_ok(ndev)) {
746 if (time_after(jiffies, atmost)) {
748 "%s: timeout waiting for carrier\n",
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.
760 if (time_before(jiffies, atleast)) {
761 printk(KERN_NOTICE "%s: carrier detect appears"
762 " untrustworthy, waiting 4 seconds\n",
770 in_dev = __in_dev_get_rcu(ndev);
772 if (!in_dev || !in_dev->ifa_list) {
774 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
775 np->name, np->dev_name);
780 np->local_ip = in_dev->ifa_list->ifa_local;
782 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
786 spin_lock_irqsave(&npinfo->rx_lock, flags);
787 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
789 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
792 /* fill up the skb queue */
795 /* last thing to do is link it to the net device structure */
796 ndev->npinfo = npinfo;
798 /* avoid racing with NAPI reading npinfo */
811 static int __init netpoll_init(void)
813 skb_queue_head_init(&skb_pool);
816 core_initcall(netpoll_init);
818 void netpoll_cleanup(struct netpoll *np)
820 struct netpoll_info *npinfo;
824 npinfo = np->dev->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);
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);
838 /* clean after last, unfinished work */
839 __skb_queue_purge(&npinfo->txq);
841 np->dev->npinfo = NULL;
851 int netpoll_trap(void)
853 return atomic_read(&trapped);
856 void netpoll_set_trap(int trap)
859 atomic_inc(&trapped);
861 atomic_dec(&trapped);
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);