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/smp_lock.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>
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;
63 if (!netif_device_present(dev) || !netif_running(dev)) {
68 local_irq_save(flags);
70 if (netif_queue_stopped(dev) ||
71 dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
72 skb_queue_head(&npinfo->txq, skb);
74 local_irq_restore(flags);
76 schedule_delayed_work(&npinfo->tx_work, HZ/10);
80 local_irq_restore(flags);
84 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
85 unsigned short ulen, __be32 saddr, __be32 daddr)
89 if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
92 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
94 if (skb->ip_summed == CHECKSUM_COMPLETE &&
95 !csum_fold(csum_add(psum, skb->csum)))
100 return __skb_checksum_complete(skb);
104 * Check whether delayed processing was scheduled for our NIC. If so,
105 * we attempt to grab the poll lock and use ->poll() to pump the card.
106 * If this fails, either we've recursed in ->poll() or it's already
107 * running on another CPU.
109 * Note: we don't mask interrupts with this lock because we're using
110 * trylock here and interrupts are already disabled in the softirq
111 * case. Further, we test the poll_owner to avoid recursion on UP
112 * systems where the lock doesn't exist.
114 * In cases where there is bi-directional communications, reading only
115 * one message at a time can lead to packets being dropped by the
116 * network adapter, forcing superfluous retries and possibly timeouts.
117 * Thus, we set our budget to greater than 1.
119 static void poll_napi(struct netpoll *np)
121 struct netpoll_info *npinfo = np->dev->npinfo;
124 if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
125 npinfo->poll_owner != smp_processor_id() &&
126 spin_trylock(&npinfo->poll_lock)) {
127 npinfo->rx_flags |= NETPOLL_RX_DROP;
128 atomic_inc(&trapped);
130 np->dev->poll(np->dev, &budget);
132 atomic_dec(&trapped);
133 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
134 spin_unlock(&npinfo->poll_lock);
138 static void service_arp_queue(struct netpoll_info *npi)
145 skb = skb_dequeue(&npi->arp_tx);
147 while (skb != NULL) {
149 skb = skb_dequeue(&npi->arp_tx);
153 void netpoll_poll(struct netpoll *np)
155 if (!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
158 /* Process pending work on NIC */
159 np->dev->poll_controller(np->dev);
163 service_arp_queue(np->dev->npinfo);
165 zap_completion_queue();
168 static void refill_skbs(void)
173 spin_lock_irqsave(&skb_pool.lock, flags);
174 while (skb_pool.qlen < MAX_SKBS) {
175 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
179 __skb_queue_tail(&skb_pool, skb);
181 spin_unlock_irqrestore(&skb_pool.lock, flags);
184 static void zap_completion_queue(void)
187 struct softnet_data *sd = &get_cpu_var(softnet_data);
189 if (sd->completion_queue) {
190 struct sk_buff *clist;
192 local_irq_save(flags);
193 clist = sd->completion_queue;
194 sd->completion_queue = NULL;
195 local_irq_restore(flags);
197 while (clist != NULL) {
198 struct sk_buff *skb = clist;
201 dev_kfree_skb_any(skb); /* put this one back */
207 put_cpu_var(softnet_data);
210 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
215 zap_completion_queue();
219 skb = alloc_skb(len, GFP_ATOMIC);
221 skb = skb_dequeue(&skb_pool);
231 atomic_set(&skb->users, 1);
232 skb_reserve(skb, reserve);
236 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
238 int status = NETDEV_TX_BUSY;
240 struct net_device *dev = np->dev;
241 struct netpoll_info *npinfo = np->dev->npinfo;
243 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
248 /* don't get messages out of order, and no recursion */
249 if (skb_queue_len(&npinfo->txq) == 0 &&
250 npinfo->poll_owner != smp_processor_id()) {
253 local_irq_save(flags);
254 if (netif_tx_trylock(dev)) {
255 /* try until next clock tick */
256 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
257 tries > 0; --tries) {
258 if (!netif_queue_stopped(dev))
259 status = dev->hard_start_xmit(skb, dev);
261 if (status == NETDEV_TX_OK)
264 /* tickle device maybe there is some cleanup */
267 udelay(USEC_PER_POLL);
269 netif_tx_unlock(dev);
271 local_irq_restore(flags);
274 if (status != NETDEV_TX_OK) {
275 skb_queue_tail(&npinfo->txq, skb);
276 schedule_delayed_work(&npinfo->tx_work,0);
280 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
282 int total_len, eth_len, ip_len, udp_len;
288 udp_len = len + sizeof(*udph);
289 ip_len = eth_len = udp_len + sizeof(*iph);
290 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
292 skb = find_skb(np, total_len, total_len - len);
296 memcpy(skb->data, msg, len);
299 skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
300 udph->source = htons(np->local_port);
301 udph->dest = htons(np->remote_port);
302 udph->len = htons(udp_len);
304 udph->check = csum_tcpudp_magic(htonl(np->local_ip),
305 htonl(np->remote_ip),
306 udp_len, IPPROTO_UDP,
307 csum_partial((unsigned char *)udph, udp_len, 0));
308 if (udph->check == 0)
309 udph->check = CSUM_MANGLED_0;
311 skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
313 /* iph->version = 4; iph->ihl = 5; */
314 put_unaligned(0x45, (unsigned char *)iph);
316 put_unaligned(htons(ip_len), &(iph->tot_len));
320 iph->protocol = IPPROTO_UDP;
322 put_unaligned(htonl(np->local_ip), &(iph->saddr));
323 put_unaligned(htonl(np->remote_ip), &(iph->daddr));
324 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
326 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
327 skb_reset_mac_header(skb);
328 skb->protocol = eth->h_proto = htons(ETH_P_IP);
329 memcpy(eth->h_source, np->local_mac, 6);
330 memcpy(eth->h_dest, np->remote_mac, 6);
334 netpoll_send_skb(np, skb);
337 static void arp_reply(struct sk_buff *skb)
339 struct netpoll_info *npinfo = skb->dev->npinfo;
341 unsigned char *arp_ptr;
342 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
345 struct sk_buff *send_skb;
346 struct netpoll *np = NULL;
348 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
353 /* No arp on this interface */
354 if (skb->dev->flags & IFF_NOARP)
357 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
358 (2 * skb->dev->addr_len) +
362 skb_reset_network_header(skb);
363 skb->h.raw = skb->data;
366 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
367 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
368 arp->ar_pro != htons(ETH_P_IP) ||
369 arp->ar_op != htons(ARPOP_REQUEST))
372 arp_ptr = (unsigned char *)(arp+1);
373 /* save the location of the src hw addr */
375 arp_ptr += skb->dev->addr_len;
376 memcpy(&sip, arp_ptr, 4);
378 /* if we actually cared about dst hw addr, it would get copied here */
379 arp_ptr += skb->dev->addr_len;
380 memcpy(&tip, arp_ptr, 4);
382 /* Should we ignore arp? */
383 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
386 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
387 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
388 LL_RESERVED_SPACE(np->dev));
393 skb_reset_network_header(send_skb);
394 arp = (struct arphdr *) skb_put(send_skb, size);
395 send_skb->dev = skb->dev;
396 send_skb->protocol = htons(ETH_P_ARP);
398 /* Fill the device header for the ARP frame */
400 if (np->dev->hard_header &&
401 np->dev->hard_header(send_skb, skb->dev, ptype,
403 send_skb->len) < 0) {
409 * Fill out the arp protocol part.
411 * we only support ethernet device type,
412 * which (according to RFC 1390) should always equal 1 (Ethernet).
415 arp->ar_hrd = htons(np->dev->type);
416 arp->ar_pro = htons(ETH_P_IP);
417 arp->ar_hln = np->dev->addr_len;
419 arp->ar_op = htons(type);
421 arp_ptr=(unsigned char *)(arp + 1);
422 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
423 arp_ptr += np->dev->addr_len;
424 memcpy(arp_ptr, &tip, 4);
426 memcpy(arp_ptr, sha, np->dev->addr_len);
427 arp_ptr += np->dev->addr_len;
428 memcpy(arp_ptr, &sip, 4);
430 netpoll_send_skb(np, send_skb);
433 int __netpoll_rx(struct sk_buff *skb)
435 int proto, len, ulen;
438 struct netpoll_info *npi = skb->dev->npinfo;
439 struct netpoll *np = npi->rx_np;
443 if (skb->dev->type != ARPHRD_ETHER)
446 /* check if netpoll clients need ARP */
447 if (skb->protocol == htons(ETH_P_ARP) &&
448 atomic_read(&trapped)) {
449 skb_queue_tail(&npi->arp_tx, skb);
453 proto = ntohs(eth_hdr(skb)->h_proto);
454 if (proto != ETH_P_IP)
456 if (skb->pkt_type == PACKET_OTHERHOST)
461 iph = (struct iphdr *)skb->data;
462 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
464 if (iph->ihl < 5 || iph->version != 4)
466 if (!pskb_may_pull(skb, iph->ihl*4))
468 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
471 len = ntohs(iph->tot_len);
472 if (skb->len < len || len < iph->ihl*4)
476 * Our transport medium may have padded the buffer out.
477 * Now We trim to the true length of the frame.
479 if (pskb_trim_rcsum(skb, len))
482 if (iph->protocol != IPPROTO_UDP)
486 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
487 ulen = ntohs(uh->len);
491 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
493 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
495 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
497 if (np->local_port && np->local_port != ntohs(uh->dest))
500 np->rx_hook(np, ntohs(uh->source),
502 ulen - sizeof(struct udphdr));
508 if (atomic_read(&trapped)) {
516 int netpoll_parse_options(struct netpoll *np, char *opt)
518 char *cur=opt, *delim;
521 if ((delim = strchr(cur, '@')) == NULL)
524 np->local_port = simple_strtol(cur, NULL, 10);
528 printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
531 if ((delim = strchr(cur, '/')) == NULL)
534 np->local_ip = ntohl(in_aton(cur));
537 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
538 np->name, HIPQUAD(np->local_ip));
543 /* parse out dev name */
544 if ((delim = strchr(cur, ',')) == NULL)
547 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
552 printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
556 if ((delim = strchr(cur, '@')) == NULL)
559 np->remote_port = simple_strtol(cur, NULL, 10);
563 printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
566 if ((delim = strchr(cur, '/')) == NULL)
569 np->remote_ip = ntohl(in_aton(cur));
572 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
573 np->name, HIPQUAD(np->remote_ip));
577 if ((delim = strchr(cur, ':')) == NULL)
580 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
582 if ((delim = strchr(cur, ':')) == NULL)
585 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
587 if ((delim = strchr(cur, ':')) == NULL)
590 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
592 if ((delim = strchr(cur, ':')) == NULL)
595 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
597 if ((delim = strchr(cur, ':')) == NULL)
600 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
602 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
605 printk(KERN_INFO "%s: remote ethernet address "
606 "%02x:%02x:%02x:%02x:%02x:%02x\n",
618 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
623 int netpoll_setup(struct netpoll *np)
625 struct net_device *ndev = NULL;
626 struct in_device *in_dev;
627 struct netpoll_info *npinfo;
632 ndev = dev_get_by_name(np->dev_name);
634 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
635 np->name, np->dev_name);
641 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
647 npinfo->rx_flags = 0;
648 npinfo->rx_np = NULL;
649 spin_lock_init(&npinfo->poll_lock);
650 npinfo->poll_owner = -1;
652 spin_lock_init(&npinfo->rx_lock);
653 skb_queue_head_init(&npinfo->arp_tx);
654 skb_queue_head_init(&npinfo->txq);
655 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
657 atomic_set(&npinfo->refcnt, 1);
659 npinfo = ndev->npinfo;
660 atomic_inc(&npinfo->refcnt);
663 if (!ndev->poll_controller) {
664 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
665 np->name, np->dev_name);
670 if (!netif_running(ndev)) {
671 unsigned long atmost, atleast;
673 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
674 np->name, np->dev_name);
677 err = dev_open(ndev);
681 printk(KERN_ERR "%s: failed to open %s\n",
682 np->name, ndev->name);
686 atleast = jiffies + HZ/10;
687 atmost = jiffies + 4*HZ;
688 while (!netif_carrier_ok(ndev)) {
689 if (time_after(jiffies, atmost)) {
691 "%s: timeout waiting for carrier\n",
698 /* If carrier appears to come up instantly, we don't
699 * trust it and pause so that we don't pump all our
700 * queued console messages into the bitbucket.
703 if (time_before(jiffies, atleast)) {
704 printk(KERN_NOTICE "%s: carrier detect appears"
705 " untrustworthy, waiting 4 seconds\n",
711 if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
712 memcpy(np->local_mac, ndev->dev_addr, 6);
716 in_dev = __in_dev_get_rcu(ndev);
718 if (!in_dev || !in_dev->ifa_list) {
720 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
721 np->name, np->dev_name);
726 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
728 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
729 np->name, HIPQUAD(np->local_ip));
733 spin_lock_irqsave(&npinfo->rx_lock, flags);
734 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
736 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
739 /* fill up the skb queue */
742 /* last thing to do is link it to the net device structure */
743 ndev->npinfo = npinfo;
745 /* avoid racing with NAPI reading npinfo */
758 static int __init netpoll_init(void)
760 skb_queue_head_init(&skb_pool);
763 core_initcall(netpoll_init);
765 void netpoll_cleanup(struct netpoll *np)
767 struct netpoll_info *npinfo;
771 npinfo = np->dev->npinfo;
773 if (npinfo->rx_np == np) {
774 spin_lock_irqsave(&npinfo->rx_lock, flags);
775 npinfo->rx_np = NULL;
776 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
777 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
780 np->dev->npinfo = NULL;
781 if (atomic_dec_and_test(&npinfo->refcnt)) {
782 skb_queue_purge(&npinfo->arp_tx);
783 skb_queue_purge(&npinfo->txq);
784 cancel_rearming_delayed_work(&npinfo->tx_work);
785 flush_scheduled_work();
797 int netpoll_trap(void)
799 return atomic_read(&trapped);
802 void netpoll_set_trap(int trap)
805 atomic_inc(&trapped);
807 atomic_dec(&trapped);
810 EXPORT_SYMBOL(netpoll_set_trap);
811 EXPORT_SYMBOL(netpoll_trap);
812 EXPORT_SYMBOL(netpoll_parse_options);
813 EXPORT_SYMBOL(netpoll_setup);
814 EXPORT_SYMBOL(netpoll_cleanup);
815 EXPORT_SYMBOL(netpoll_send_udp);
816 EXPORT_SYMBOL(netpoll_poll);