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>
29 * We maintain a small pool of fully-sized skbs, to make sure the
30 * message gets out even in extreme OOM situations.
33 #define MAX_UDP_CHUNK 1460
35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
37 static struct sk_buff_head skb_pool;
39 static atomic_t trapped;
41 #define USEC_PER_POLL 50
42 #define NETPOLL_RX_ENABLED 1
44 #define MAX_SKB_SIZE \
45 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
46 sizeof(struct iphdr) + sizeof(struct ethhdr))
48 static void zap_completion_queue(void);
49 static void arp_reply(struct sk_buff *skb);
51 static void queue_process(struct work_struct *work)
53 struct netpoll_info *npinfo =
54 container_of(work, struct netpoll_info, tx_work.work);
58 while ((skb = skb_dequeue(&npinfo->txq))) {
59 struct net_device *dev = skb->dev;
61 if (!netif_device_present(dev) || !netif_running(dev)) {
66 local_irq_save(flags);
68 if ((netif_queue_stopped(dev) ||
69 netif_subqueue_stopped(dev, skb)) ||
70 dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
71 skb_queue_head(&npinfo->txq, skb);
73 local_irq_restore(flags);
75 schedule_delayed_work(&npinfo->tx_work, HZ/10);
79 local_irq_restore(flags);
83 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
84 unsigned short ulen, __be32 saddr, __be32 daddr)
88 if (uh->check == 0 || skb_csum_unnecessary(skb))
91 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
93 if (skb->ip_summed == CHECKSUM_COMPLETE &&
94 !csum_fold(csum_add(psum, skb->csum)))
99 return __skb_checksum_complete(skb);
103 * Check whether delayed processing was scheduled for our NIC. If so,
104 * we attempt to grab the poll lock and use ->poll() to pump the card.
105 * If this fails, either we've recursed in ->poll() or it's already
106 * running on another CPU.
108 * Note: we don't mask interrupts with this lock because we're using
109 * trylock here and interrupts are already disabled in the softirq
110 * case. Further, we test the poll_owner to avoid recursion on UP
111 * systems where the lock doesn't exist.
113 * In cases where there is bi-directional communications, reading only
114 * one message at a time can lead to packets being dropped by the
115 * network adapter, forcing superfluous retries and possibly timeouts.
116 * Thus, we set our budget to greater than 1.
118 static int poll_one_napi(struct netpoll_info *npinfo,
119 struct napi_struct *napi, int budget)
123 /* net_rx_action's ->poll() invocations and our's are
124 * synchronized by this test which is only made while
125 * holding the napi->poll_lock.
127 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
130 atomic_inc(&trapped);
132 work = napi->poll(napi, budget);
134 atomic_dec(&trapped);
136 return budget - work;
139 static void poll_napi(struct net_device *dev)
141 struct napi_struct *napi;
144 list_for_each_entry(napi, &dev->napi_list, dev_list) {
145 if (napi->poll_owner != smp_processor_id() &&
146 spin_trylock(&napi->poll_lock)) {
147 budget = poll_one_napi(dev->npinfo, napi, budget);
148 spin_unlock(&napi->poll_lock);
156 static void service_arp_queue(struct netpoll_info *npi)
161 while ((skb = skb_dequeue(&npi->arp_tx)))
166 void netpoll_poll(struct netpoll *np)
168 struct net_device *dev = np->dev;
170 if (!dev || !netif_running(dev) || !dev->poll_controller)
173 /* Process pending work on NIC */
174 dev->poll_controller(dev);
178 service_arp_queue(dev->npinfo);
180 zap_completion_queue();
183 static void refill_skbs(void)
188 spin_lock_irqsave(&skb_pool.lock, flags);
189 while (skb_pool.qlen < MAX_SKBS) {
190 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
194 __skb_queue_tail(&skb_pool, skb);
196 spin_unlock_irqrestore(&skb_pool.lock, flags);
199 static void zap_completion_queue(void)
202 struct softnet_data *sd = &get_cpu_var(softnet_data);
204 if (sd->completion_queue) {
205 struct sk_buff *clist;
207 local_irq_save(flags);
208 clist = sd->completion_queue;
209 sd->completion_queue = NULL;
210 local_irq_restore(flags);
212 while (clist != NULL) {
213 struct sk_buff *skb = clist;
216 dev_kfree_skb_any(skb); /* put this one back */
222 put_cpu_var(softnet_data);
225 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
230 zap_completion_queue();
234 skb = alloc_skb(len, GFP_ATOMIC);
236 skb = skb_dequeue(&skb_pool);
246 atomic_set(&skb->users, 1);
247 skb_reserve(skb, reserve);
251 static int netpoll_owner_active(struct net_device *dev)
253 struct napi_struct *napi;
255 list_for_each_entry(napi, &dev->napi_list, dev_list) {
256 if (napi->poll_owner == smp_processor_id())
262 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
264 int status = NETDEV_TX_BUSY;
266 struct net_device *dev = np->dev;
267 struct netpoll_info *npinfo = np->dev->npinfo;
269 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
274 /* don't get messages out of order, and no recursion */
275 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
278 local_irq_save(flags);
279 /* try until next clock tick */
280 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
281 tries > 0; --tries) {
282 if (netif_tx_trylock(dev)) {
283 if (!netif_queue_stopped(dev) &&
284 !netif_subqueue_stopped(dev, skb))
285 status = dev->hard_start_xmit(skb, dev);
286 netif_tx_unlock(dev);
288 if (status == NETDEV_TX_OK)
293 /* tickle device maybe there is some cleanup */
296 udelay(USEC_PER_POLL);
298 local_irq_restore(flags);
301 if (status != NETDEV_TX_OK) {
302 skb_queue_tail(&npinfo->txq, skb);
303 schedule_delayed_work(&npinfo->tx_work,0);
307 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
309 int total_len, eth_len, ip_len, udp_len;
315 udp_len = len + sizeof(*udph);
316 ip_len = eth_len = udp_len + sizeof(*iph);
317 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
319 skb = find_skb(np, total_len, total_len - len);
323 skb_copy_to_linear_data(skb, msg, len);
326 skb_push(skb, sizeof(*udph));
327 skb_reset_transport_header(skb);
329 udph->source = htons(np->local_port);
330 udph->dest = htons(np->remote_port);
331 udph->len = htons(udp_len);
333 udph->check = csum_tcpudp_magic(htonl(np->local_ip),
334 htonl(np->remote_ip),
335 udp_len, IPPROTO_UDP,
336 csum_partial((unsigned char *)udph, udp_len, 0));
337 if (udph->check == 0)
338 udph->check = CSUM_MANGLED_0;
340 skb_push(skb, sizeof(*iph));
341 skb_reset_network_header(skb);
344 /* iph->version = 4; iph->ihl = 5; */
345 put_unaligned(0x45, (unsigned char *)iph);
347 put_unaligned(htons(ip_len), &(iph->tot_len));
351 iph->protocol = IPPROTO_UDP;
353 put_unaligned(htonl(np->local_ip), &(iph->saddr));
354 put_unaligned(htonl(np->remote_ip), &(iph->daddr));
355 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
357 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
358 skb_reset_mac_header(skb);
359 skb->protocol = eth->h_proto = htons(ETH_P_IP);
360 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
361 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
365 netpoll_send_skb(np, skb);
368 static void arp_reply(struct sk_buff *skb)
370 struct netpoll_info *npinfo = skb->dev->npinfo;
372 unsigned char *arp_ptr;
373 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
376 struct sk_buff *send_skb;
377 struct netpoll *np = NULL;
379 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
384 /* No arp on this interface */
385 if (skb->dev->flags & IFF_NOARP)
388 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
389 (2 * skb->dev->addr_len) +
393 skb_reset_network_header(skb);
394 skb_reset_transport_header(skb);
397 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
398 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
399 arp->ar_pro != htons(ETH_P_IP) ||
400 arp->ar_op != htons(ARPOP_REQUEST))
403 arp_ptr = (unsigned char *)(arp+1);
404 /* save the location of the src hw addr */
406 arp_ptr += skb->dev->addr_len;
407 memcpy(&sip, arp_ptr, 4);
409 /* if we actually cared about dst hw addr, it would get copied here */
410 arp_ptr += skb->dev->addr_len;
411 memcpy(&tip, arp_ptr, 4);
413 /* Should we ignore arp? */
414 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
417 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
418 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
419 LL_RESERVED_SPACE(np->dev));
424 skb_reset_network_header(send_skb);
425 arp = (struct arphdr *) skb_put(send_skb, size);
426 send_skb->dev = skb->dev;
427 send_skb->protocol = htons(ETH_P_ARP);
429 /* Fill the device header for the ARP frame */
430 if (dev_hard_header(send_skb, skb->dev, ptype,
431 sha, np->dev->dev_addr,
432 send_skb->len) < 0) {
438 * Fill out the arp protocol part.
440 * we only support ethernet device type,
441 * which (according to RFC 1390) should always equal 1 (Ethernet).
444 arp->ar_hrd = htons(np->dev->type);
445 arp->ar_pro = htons(ETH_P_IP);
446 arp->ar_hln = np->dev->addr_len;
448 arp->ar_op = htons(type);
450 arp_ptr=(unsigned char *)(arp + 1);
451 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
452 arp_ptr += np->dev->addr_len;
453 memcpy(arp_ptr, &tip, 4);
455 memcpy(arp_ptr, sha, np->dev->addr_len);
456 arp_ptr += np->dev->addr_len;
457 memcpy(arp_ptr, &sip, 4);
459 netpoll_send_skb(np, send_skb);
462 int __netpoll_rx(struct sk_buff *skb)
464 int proto, len, ulen;
467 struct netpoll_info *npi = skb->dev->npinfo;
468 struct netpoll *np = npi->rx_np;
472 if (skb->dev->type != ARPHRD_ETHER)
475 /* if receive ARP during middle of NAPI poll, then queue */
476 if (skb->protocol == htons(ETH_P_ARP) &&
477 atomic_read(&trapped)) {
478 skb_queue_tail(&npi->arp_tx, skb);
482 proto = ntohs(eth_hdr(skb)->h_proto);
483 if (proto != ETH_P_IP)
485 if (skb->pkt_type == PACKET_OTHERHOST)
490 iph = (struct iphdr *)skb->data;
491 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
493 if (iph->ihl < 5 || iph->version != 4)
495 if (!pskb_may_pull(skb, iph->ihl*4))
497 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
500 len = ntohs(iph->tot_len);
501 if (skb->len < len || len < iph->ihl*4)
505 * Our transport medium may have padded the buffer out.
506 * Now We trim to the true length of the frame.
508 if (pskb_trim_rcsum(skb, len))
511 if (iph->protocol != IPPROTO_UDP)
515 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
516 ulen = ntohs(uh->len);
520 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
522 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
524 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
526 if (np->local_port && np->local_port != ntohs(uh->dest))
529 np->rx_hook(np, ntohs(uh->source),
531 ulen - sizeof(struct udphdr));
537 /* If packet received while already in poll then just
540 if (atomic_read(&trapped)) {
548 void netpoll_print_options(struct netpoll *np)
550 DECLARE_MAC_BUF(mac);
551 printk(KERN_INFO "%s: local port %d\n",
552 np->name, np->local_port);
553 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
554 np->name, HIPQUAD(np->local_ip));
555 printk(KERN_INFO "%s: interface %s\n",
556 np->name, np->dev_name);
557 printk(KERN_INFO "%s: remote port %d\n",
558 np->name, np->remote_port);
559 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
560 np->name, HIPQUAD(np->remote_ip));
561 printk(KERN_INFO "%s: remote ethernet address %s\n",
562 np->name, print_mac(mac, np->remote_mac));
565 int netpoll_parse_options(struct netpoll *np, char *opt)
567 char *cur=opt, *delim;
570 if ((delim = strchr(cur, '@')) == NULL)
573 np->local_port = simple_strtol(cur, NULL, 10);
579 if ((delim = strchr(cur, '/')) == NULL)
582 np->local_ip = ntohl(in_aton(cur));
588 /* parse out dev name */
589 if ((delim = strchr(cur, ',')) == NULL)
592 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
599 if ((delim = strchr(cur, '@')) == NULL)
602 np->remote_port = simple_strtol(cur, NULL, 10);
608 if ((delim = strchr(cur, '/')) == NULL)
611 np->remote_ip = ntohl(in_aton(cur));
616 if ((delim = strchr(cur, ':')) == NULL)
619 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
621 if ((delim = strchr(cur, ':')) == NULL)
624 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
626 if ((delim = strchr(cur, ':')) == NULL)
629 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
631 if ((delim = strchr(cur, ':')) == NULL)
634 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
636 if ((delim = strchr(cur, ':')) == NULL)
639 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
641 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
644 netpoll_print_options(np);
649 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
654 int netpoll_setup(struct netpoll *np)
656 struct net_device *ndev = NULL;
657 struct in_device *in_dev;
658 struct netpoll_info *npinfo;
663 ndev = dev_get_by_name(&init_net, np->dev_name);
665 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
666 np->name, np->dev_name);
672 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
678 npinfo->rx_flags = 0;
679 npinfo->rx_np = NULL;
681 spin_lock_init(&npinfo->rx_lock);
682 skb_queue_head_init(&npinfo->arp_tx);
683 skb_queue_head_init(&npinfo->txq);
684 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
686 atomic_set(&npinfo->refcnt, 1);
688 npinfo = ndev->npinfo;
689 atomic_inc(&npinfo->refcnt);
692 if (!ndev->poll_controller) {
693 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
694 np->name, np->dev_name);
699 if (!netif_running(ndev)) {
700 unsigned long atmost, atleast;
702 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
703 np->name, np->dev_name);
706 err = dev_open(ndev);
710 printk(KERN_ERR "%s: failed to open %s\n",
711 np->name, ndev->name);
715 atleast = jiffies + HZ/10;
716 atmost = jiffies + 4*HZ;
717 while (!netif_carrier_ok(ndev)) {
718 if (time_after(jiffies, atmost)) {
720 "%s: timeout waiting for carrier\n",
727 /* If carrier appears to come up instantly, we don't
728 * trust it and pause so that we don't pump all our
729 * queued console messages into the bitbucket.
732 if (time_before(jiffies, atleast)) {
733 printk(KERN_NOTICE "%s: carrier detect appears"
734 " untrustworthy, waiting 4 seconds\n",
742 in_dev = __in_dev_get_rcu(ndev);
744 if (!in_dev || !in_dev->ifa_list) {
746 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
747 np->name, np->dev_name);
752 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
754 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
755 np->name, HIPQUAD(np->local_ip));
759 spin_lock_irqsave(&npinfo->rx_lock, flags);
760 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
762 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
765 /* fill up the skb queue */
768 /* last thing to do is link it to the net device structure */
769 ndev->npinfo = npinfo;
771 /* avoid racing with NAPI reading npinfo */
784 static int __init netpoll_init(void)
786 skb_queue_head_init(&skb_pool);
789 core_initcall(netpoll_init);
791 void netpoll_cleanup(struct netpoll *np)
793 struct netpoll_info *npinfo;
797 npinfo = np->dev->npinfo;
799 if (npinfo->rx_np == np) {
800 spin_lock_irqsave(&npinfo->rx_lock, flags);
801 npinfo->rx_np = NULL;
802 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
803 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
806 if (atomic_dec_and_test(&npinfo->refcnt)) {
807 skb_queue_purge(&npinfo->arp_tx);
808 skb_queue_purge(&npinfo->txq);
809 cancel_rearming_delayed_work(&npinfo->tx_work);
811 /* clean after last, unfinished work */
812 __skb_queue_purge(&npinfo->txq);
814 np->dev->npinfo = NULL;
824 int netpoll_trap(void)
826 return atomic_read(&trapped);
829 void netpoll_set_trap(int trap)
832 atomic_inc(&trapped);
834 atomic_dec(&trapped);
837 EXPORT_SYMBOL(netpoll_set_trap);
838 EXPORT_SYMBOL(netpoll_trap);
839 EXPORT_SYMBOL(netpoll_print_options);
840 EXPORT_SYMBOL(netpoll_parse_options);
841 EXPORT_SYMBOL(netpoll_setup);
842 EXPORT_SYMBOL(netpoll_cleanup);
843 EXPORT_SYMBOL(netpoll_send_udp);
844 EXPORT_SYMBOL(netpoll_poll);