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/netdevice.h>
13 #include <linux/etherdevice.h>
14 #include <linux/string.h>
15 #include <linux/if_arp.h>
16 #include <linux/inetdevice.h>
17 #include <linux/inet.h>
18 #include <linux/interrupt.h>
19 #include <linux/netpoll.h>
20 #include <linux/sched.h>
21 #include <linux/delay.h>
22 #include <linux/rcupdate.h>
23 #include <linux/workqueue.h>
26 #include <asm/unaligned.h>
27 #include <trace/napi.h>
30 * We maintain a small pool of fully-sized skbs, to make sure the
31 * message gets out even in extreme OOM situations.
34 #define MAX_UDP_CHUNK 1460
36 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
38 static struct sk_buff_head skb_pool;
40 static atomic_t trapped;
42 #define USEC_PER_POLL 50
43 #define NETPOLL_RX_ENABLED 1
44 #define NETPOLL_RX_DROP 2
46 #define MAX_SKB_SIZE \
47 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
48 sizeof(struct iphdr) + sizeof(struct ethhdr))
50 static void zap_completion_queue(void);
51 static void arp_reply(struct sk_buff *skb);
53 static void queue_process(struct work_struct *work)
55 struct netpoll_info *npinfo =
56 container_of(work, struct netpoll_info, tx_work.work);
60 while ((skb = skb_dequeue(&npinfo->txq))) {
61 struct net_device *dev = skb->dev;
62 const struct net_device_ops *ops = dev->netdev_ops;
63 struct netdev_queue *txq;
65 if (!netif_device_present(dev) || !netif_running(dev)) {
70 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
72 local_irq_save(flags);
73 __netif_tx_lock(txq, smp_processor_id());
74 if (netif_tx_queue_stopped(txq) ||
75 netif_tx_queue_frozen(txq) ||
76 ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
77 skb_queue_head(&npinfo->txq, skb);
78 __netif_tx_unlock(txq);
79 local_irq_restore(flags);
81 schedule_delayed_work(&npinfo->tx_work, HZ/10);
84 __netif_tx_unlock(txq);
85 local_irq_restore(flags);
89 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
90 unsigned short ulen, __be32 saddr, __be32 daddr)
94 if (uh->check == 0 || skb_csum_unnecessary(skb))
97 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
99 if (skb->ip_summed == CHECKSUM_COMPLETE &&
100 !csum_fold(csum_add(psum, skb->csum)))
105 return __skb_checksum_complete(skb);
109 * Check whether delayed processing was scheduled for our NIC. If so,
110 * we attempt to grab the poll lock and use ->poll() to pump the card.
111 * If this fails, either we've recursed in ->poll() or it's already
112 * running on another CPU.
114 * Note: we don't mask interrupts with this lock because we're using
115 * trylock here and interrupts are already disabled in the softirq
116 * case. Further, we test the poll_owner to avoid recursion on UP
117 * systems where the lock doesn't exist.
119 * In cases where there is bi-directional communications, reading only
120 * one message at a time can lead to packets being dropped by the
121 * network adapter, forcing superfluous retries and possibly timeouts.
122 * Thus, we set our budget to greater than 1.
124 static int poll_one_napi(struct netpoll_info *npinfo,
125 struct napi_struct *napi, int budget)
129 /* net_rx_action's ->poll() invocations and our's are
130 * synchronized by this test which is only made while
131 * holding the napi->poll_lock.
133 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
136 npinfo->rx_flags |= NETPOLL_RX_DROP;
137 atomic_inc(&trapped);
138 set_bit(NAPI_STATE_NPSVC, &napi->state);
140 work = napi->poll(napi, budget);
141 trace_napi_poll(napi->dev);
143 clear_bit(NAPI_STATE_NPSVC, &napi->state);
144 atomic_dec(&trapped);
145 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
147 return budget - work;
150 static void poll_napi(struct net_device *dev)
152 struct napi_struct *napi;
155 list_for_each_entry(napi, &dev->napi_list, dev_list) {
156 if (napi->poll_owner != smp_processor_id() &&
157 spin_trylock(&napi->poll_lock)) {
158 budget = poll_one_napi(dev->npinfo, napi, budget);
159 spin_unlock(&napi->poll_lock);
167 static void service_arp_queue(struct netpoll_info *npi)
172 while ((skb = skb_dequeue(&npi->arp_tx)))
177 void netpoll_poll(struct netpoll *np)
179 struct net_device *dev = np->dev;
180 const struct net_device_ops *ops;
182 if (!dev || !netif_running(dev))
185 ops = dev->netdev_ops;
186 if (!ops->ndo_poll_controller)
189 /* Process pending work on NIC */
190 ops->ndo_poll_controller(dev);
194 service_arp_queue(dev->npinfo);
196 zap_completion_queue();
199 static void refill_skbs(void)
204 spin_lock_irqsave(&skb_pool.lock, flags);
205 while (skb_pool.qlen < MAX_SKBS) {
206 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
210 __skb_queue_tail(&skb_pool, skb);
212 spin_unlock_irqrestore(&skb_pool.lock, flags);
215 static void zap_completion_queue(void)
218 struct softnet_data *sd = &get_cpu_var(softnet_data);
220 if (sd->completion_queue) {
221 struct sk_buff *clist;
223 local_irq_save(flags);
224 clist = sd->completion_queue;
225 sd->completion_queue = NULL;
226 local_irq_restore(flags);
228 while (clist != NULL) {
229 struct sk_buff *skb = clist;
231 if (skb->destructor) {
232 atomic_inc(&skb->users);
233 dev_kfree_skb_any(skb); /* put this one back */
240 put_cpu_var(softnet_data);
243 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
248 zap_completion_queue();
252 skb = alloc_skb(len, GFP_ATOMIC);
254 skb = skb_dequeue(&skb_pool);
264 atomic_set(&skb->users, 1);
265 skb_reserve(skb, reserve);
269 static int netpoll_owner_active(struct net_device *dev)
271 struct napi_struct *napi;
273 list_for_each_entry(napi, &dev->napi_list, dev_list) {
274 if (napi->poll_owner == smp_processor_id())
280 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
282 int status = NETDEV_TX_BUSY;
284 struct net_device *dev = np->dev;
285 const struct net_device_ops *ops = dev->netdev_ops;
286 struct netpoll_info *npinfo = np->dev->npinfo;
288 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
293 /* don't get messages out of order, and no recursion */
294 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
295 struct netdev_queue *txq;
298 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
300 local_irq_save(flags);
301 /* try until next clock tick */
302 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
303 tries > 0; --tries) {
304 if (__netif_tx_trylock(txq)) {
305 if (!netif_tx_queue_stopped(txq))
306 status = ops->ndo_start_xmit(skb, dev);
307 __netif_tx_unlock(txq);
309 if (status == NETDEV_TX_OK)
314 /* tickle device maybe there is some cleanup */
317 udelay(USEC_PER_POLL);
319 local_irq_restore(flags);
322 if (status != NETDEV_TX_OK) {
323 skb_queue_tail(&npinfo->txq, skb);
324 schedule_delayed_work(&npinfo->tx_work,0);
328 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
330 int total_len, eth_len, ip_len, udp_len;
336 udp_len = len + sizeof(*udph);
337 ip_len = eth_len = udp_len + sizeof(*iph);
338 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
340 skb = find_skb(np, total_len, total_len - len);
344 skb_copy_to_linear_data(skb, msg, len);
347 skb_push(skb, sizeof(*udph));
348 skb_reset_transport_header(skb);
350 udph->source = htons(np->local_port);
351 udph->dest = htons(np->remote_port);
352 udph->len = htons(udp_len);
354 udph->check = csum_tcpudp_magic(np->local_ip,
356 udp_len, IPPROTO_UDP,
357 csum_partial(udph, udp_len, 0));
358 if (udph->check == 0)
359 udph->check = CSUM_MANGLED_0;
361 skb_push(skb, sizeof(*iph));
362 skb_reset_network_header(skb);
365 /* iph->version = 4; iph->ihl = 5; */
366 put_unaligned(0x45, (unsigned char *)iph);
368 put_unaligned(htons(ip_len), &(iph->tot_len));
372 iph->protocol = IPPROTO_UDP;
374 put_unaligned(np->local_ip, &(iph->saddr));
375 put_unaligned(np->remote_ip, &(iph->daddr));
376 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
378 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
379 skb_reset_mac_header(skb);
380 skb->protocol = eth->h_proto = htons(ETH_P_IP);
381 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
382 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
386 netpoll_send_skb(np, skb);
389 static void arp_reply(struct sk_buff *skb)
391 struct netpoll_info *npinfo = skb->dev->npinfo;
393 unsigned char *arp_ptr;
394 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
397 struct sk_buff *send_skb;
398 struct netpoll *np = NULL;
400 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
405 /* No arp on this interface */
406 if (skb->dev->flags & IFF_NOARP)
409 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
412 skb_reset_network_header(skb);
413 skb_reset_transport_header(skb);
416 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
417 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
418 arp->ar_pro != htons(ETH_P_IP) ||
419 arp->ar_op != htons(ARPOP_REQUEST))
422 arp_ptr = (unsigned char *)(arp+1);
423 /* save the location of the src hw addr */
425 arp_ptr += skb->dev->addr_len;
426 memcpy(&sip, arp_ptr, 4);
428 /* if we actually cared about dst hw addr, it would get copied here */
429 arp_ptr += skb->dev->addr_len;
430 memcpy(&tip, arp_ptr, 4);
432 /* Should we ignore arp? */
433 if (tip != np->local_ip ||
434 ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
437 size = arp_hdr_len(skb->dev);
438 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
439 LL_RESERVED_SPACE(np->dev));
444 skb_reset_network_header(send_skb);
445 arp = (struct arphdr *) skb_put(send_skb, size);
446 send_skb->dev = skb->dev;
447 send_skb->protocol = htons(ETH_P_ARP);
449 /* Fill the device header for the ARP frame */
450 if (dev_hard_header(send_skb, skb->dev, ptype,
451 sha, np->dev->dev_addr,
452 send_skb->len) < 0) {
458 * Fill out the arp protocol part.
460 * we only support ethernet device type,
461 * which (according to RFC 1390) should always equal 1 (Ethernet).
464 arp->ar_hrd = htons(np->dev->type);
465 arp->ar_pro = htons(ETH_P_IP);
466 arp->ar_hln = np->dev->addr_len;
468 arp->ar_op = htons(type);
470 arp_ptr=(unsigned char *)(arp + 1);
471 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
472 arp_ptr += np->dev->addr_len;
473 memcpy(arp_ptr, &tip, 4);
475 memcpy(arp_ptr, sha, np->dev->addr_len);
476 arp_ptr += np->dev->addr_len;
477 memcpy(arp_ptr, &sip, 4);
479 netpoll_send_skb(np, send_skb);
482 int __netpoll_rx(struct sk_buff *skb)
484 int proto, len, ulen;
487 struct netpoll_info *npi = skb->dev->npinfo;
488 struct netpoll *np = npi->rx_np;
492 if (skb->dev->type != ARPHRD_ETHER)
495 /* check if netpoll clients need ARP */
496 if (skb->protocol == htons(ETH_P_ARP) &&
497 atomic_read(&trapped)) {
498 skb_queue_tail(&npi->arp_tx, skb);
502 proto = ntohs(eth_hdr(skb)->h_proto);
503 if (proto != ETH_P_IP)
505 if (skb->pkt_type == PACKET_OTHERHOST)
510 iph = (struct iphdr *)skb->data;
511 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
513 if (iph->ihl < 5 || iph->version != 4)
515 if (!pskb_may_pull(skb, iph->ihl*4))
517 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
520 len = ntohs(iph->tot_len);
521 if (skb->len < len || len < iph->ihl*4)
525 * Our transport medium may have padded the buffer out.
526 * Now We trim to the true length of the frame.
528 if (pskb_trim_rcsum(skb, len))
531 if (iph->protocol != IPPROTO_UDP)
535 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
536 ulen = ntohs(uh->len);
540 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
542 if (np->local_ip && np->local_ip != iph->daddr)
544 if (np->remote_ip && np->remote_ip != iph->saddr)
546 if (np->local_port && np->local_port != ntohs(uh->dest))
549 np->rx_hook(np, ntohs(uh->source),
551 ulen - sizeof(struct udphdr));
557 if (atomic_read(&trapped)) {
565 void netpoll_print_options(struct netpoll *np)
567 printk(KERN_INFO "%s: local port %d\n",
568 np->name, np->local_port);
569 printk(KERN_INFO "%s: local IP %pI4\n",
570 np->name, &np->local_ip);
571 printk(KERN_INFO "%s: interface %s\n",
572 np->name, np->dev_name);
573 printk(KERN_INFO "%s: remote port %d\n",
574 np->name, np->remote_port);
575 printk(KERN_INFO "%s: remote IP %pI4\n",
576 np->name, &np->remote_ip);
577 printk(KERN_INFO "%s: remote ethernet address %pM\n",
578 np->name, np->remote_mac);
581 int netpoll_parse_options(struct netpoll *np, char *opt)
583 char *cur=opt, *delim;
586 if ((delim = strchr(cur, '@')) == NULL)
589 np->local_port = simple_strtol(cur, NULL, 10);
595 if ((delim = strchr(cur, '/')) == NULL)
598 np->local_ip = in_aton(cur);
604 /* parse out dev name */
605 if ((delim = strchr(cur, ',')) == NULL)
608 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
615 if ((delim = strchr(cur, '@')) == NULL)
618 np->remote_port = simple_strtol(cur, NULL, 10);
624 if ((delim = strchr(cur, '/')) == NULL)
627 np->remote_ip = in_aton(cur);
632 if ((delim = strchr(cur, ':')) == NULL)
635 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
637 if ((delim = strchr(cur, ':')) == NULL)
640 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
642 if ((delim = strchr(cur, ':')) == NULL)
645 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
647 if ((delim = strchr(cur, ':')) == NULL)
650 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
652 if ((delim = strchr(cur, ':')) == NULL)
655 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
657 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
660 netpoll_print_options(np);
665 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
670 int netpoll_setup(struct netpoll *np)
672 struct net_device *ndev = NULL;
673 struct in_device *in_dev;
674 struct netpoll_info *npinfo;
679 ndev = dev_get_by_name(&init_net, np->dev_name);
681 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
682 np->name, np->dev_name);
688 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
694 npinfo->rx_flags = 0;
695 npinfo->rx_np = NULL;
697 spin_lock_init(&npinfo->rx_lock);
698 skb_queue_head_init(&npinfo->arp_tx);
699 skb_queue_head_init(&npinfo->txq);
700 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
702 atomic_set(&npinfo->refcnt, 1);
704 npinfo = ndev->npinfo;
705 atomic_inc(&npinfo->refcnt);
708 if (!ndev->netdev_ops->ndo_poll_controller) {
709 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
710 np->name, np->dev_name);
715 if (!netif_running(ndev)) {
716 unsigned long atmost, atleast;
718 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
719 np->name, np->dev_name);
722 err = dev_open(ndev);
726 printk(KERN_ERR "%s: failed to open %s\n",
727 np->name, ndev->name);
731 atleast = jiffies + HZ/10;
732 atmost = jiffies + 4*HZ;
733 while (!netif_carrier_ok(ndev)) {
734 if (time_after(jiffies, atmost)) {
736 "%s: timeout waiting for carrier\n",
743 /* If carrier appears to come up instantly, we don't
744 * trust it and pause so that we don't pump all our
745 * queued console messages into the bitbucket.
748 if (time_before(jiffies, atleast)) {
749 printk(KERN_NOTICE "%s: carrier detect appears"
750 " untrustworthy, waiting 4 seconds\n",
758 in_dev = __in_dev_get_rcu(ndev);
760 if (!in_dev || !in_dev->ifa_list) {
762 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
763 np->name, np->dev_name);
768 np->local_ip = in_dev->ifa_list->ifa_local;
770 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
774 spin_lock_irqsave(&npinfo->rx_lock, flags);
775 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
777 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
780 /* fill up the skb queue */
783 /* last thing to do is link it to the net device structure */
784 ndev->npinfo = npinfo;
786 /* avoid racing with NAPI reading npinfo */
799 static int __init netpoll_init(void)
801 skb_queue_head_init(&skb_pool);
804 core_initcall(netpoll_init);
806 void netpoll_cleanup(struct netpoll *np)
808 struct netpoll_info *npinfo;
812 npinfo = np->dev->npinfo;
814 if (npinfo->rx_np == np) {
815 spin_lock_irqsave(&npinfo->rx_lock, flags);
816 npinfo->rx_np = NULL;
817 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
818 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
821 if (atomic_dec_and_test(&npinfo->refcnt)) {
822 skb_queue_purge(&npinfo->arp_tx);
823 skb_queue_purge(&npinfo->txq);
824 cancel_rearming_delayed_work(&npinfo->tx_work);
826 /* clean after last, unfinished work */
827 __skb_queue_purge(&npinfo->txq);
829 np->dev->npinfo = NULL;
839 int netpoll_trap(void)
841 return atomic_read(&trapped);
844 void netpoll_set_trap(int trap)
847 atomic_inc(&trapped);
849 atomic_dec(&trapped);
852 EXPORT_SYMBOL(netpoll_set_trap);
853 EXPORT_SYMBOL(netpoll_trap);
854 EXPORT_SYMBOL(netpoll_print_options);
855 EXPORT_SYMBOL(netpoll_parse_options);
856 EXPORT_SYMBOL(netpoll_setup);
857 EXPORT_SYMBOL(netpoll_cleanup);
858 EXPORT_SYMBOL(netpoll_send_udp);
859 EXPORT_SYMBOL(netpoll_poll);