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)
37 #define MAX_RETRIES 20000
39 static DEFINE_SPINLOCK(skb_list_lock
);
41 static struct sk_buff
*skbs
;
43 static DEFINE_SPINLOCK(queue_lock
);
44 static int queue_depth
;
45 static struct sk_buff
*queue_head
, *queue_tail
;
47 static atomic_t trapped
;
49 #define NETPOLL_RX_ENABLED 1
50 #define NETPOLL_RX_DROP 2
52 #define MAX_SKB_SIZE \
53 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
54 sizeof(struct iphdr) + sizeof(struct ethhdr))
56 static void zap_completion_queue(void);
58 static void queue_process(void *p
)
64 spin_lock_irqsave(&queue_lock
, flags
);
67 queue_head
= skb
->next
;
68 if (skb
== queue_tail
)
73 spin_unlock_irqrestore(&queue_lock
, flags
);
79 static DECLARE_WORK(send_queue
, queue_process
, NULL
);
81 void netpoll_queue(struct sk_buff
*skb
)
85 if (queue_depth
== MAX_QUEUE_DEPTH
) {
90 spin_lock_irqsave(&queue_lock
, flags
);
94 queue_tail
->next
= skb
;
97 spin_unlock_irqrestore(&queue_lock
, flags
);
99 schedule_work(&send_queue
);
102 static int checksum_udp(struct sk_buff
*skb
, struct udphdr
*uh
,
103 unsigned short ulen
, u32 saddr
, u32 daddr
)
107 if (uh
->check
== 0 || skb
->ip_summed
== CHECKSUM_UNNECESSARY
)
110 psum
= csum_tcpudp_nofold(saddr
, daddr
, ulen
, IPPROTO_UDP
, 0);
112 if (skb
->ip_summed
== CHECKSUM_HW
&&
113 !(u16
)csum_fold(csum_add(psum
, skb
->csum
)))
118 return __skb_checksum_complete(skb
);
122 * Check whether delayed processing was scheduled for our NIC. If so,
123 * we attempt to grab the poll lock and use ->poll() to pump the card.
124 * If this fails, either we've recursed in ->poll() or it's already
125 * running on another CPU.
127 * Note: we don't mask interrupts with this lock because we're using
128 * trylock here and interrupts are already disabled in the softirq
129 * case. Further, we test the poll_owner to avoid recursion on UP
130 * systems where the lock doesn't exist.
132 * In cases where there is bi-directional communications, reading only
133 * one message at a time can lead to packets being dropped by the
134 * network adapter, forcing superfluous retries and possibly timeouts.
135 * Thus, we set our budget to greater than 1.
137 static void poll_napi(struct netpoll
*np
)
139 struct netpoll_info
*npinfo
= np
->dev
->npinfo
;
142 if (test_bit(__LINK_STATE_RX_SCHED
, &np
->dev
->state
) &&
143 npinfo
->poll_owner
!= smp_processor_id() &&
144 spin_trylock(&npinfo
->poll_lock
)) {
145 npinfo
->rx_flags
|= NETPOLL_RX_DROP
;
146 atomic_inc(&trapped
);
148 np
->dev
->poll(np
->dev
, &budget
);
150 atomic_dec(&trapped
);
151 npinfo
->rx_flags
&= ~NETPOLL_RX_DROP
;
152 spin_unlock(&npinfo
->poll_lock
);
156 void netpoll_poll(struct netpoll
*np
)
158 if(!np
->dev
|| !netif_running(np
->dev
) || !np
->dev
->poll_controller
)
161 /* Process pending work on NIC */
162 np
->dev
->poll_controller(np
->dev
);
166 zap_completion_queue();
169 static void refill_skbs(void)
174 spin_lock_irqsave(&skb_list_lock
, flags
);
175 while (nr_skbs
< MAX_SKBS
) {
176 skb
= alloc_skb(MAX_SKB_SIZE
, GFP_ATOMIC
);
184 spin_unlock_irqrestore(&skb_list_lock
, flags
);
187 static void zap_completion_queue(void)
190 struct softnet_data
*sd
= &get_cpu_var(softnet_data
);
192 if (sd
->completion_queue
) {
193 struct sk_buff
*clist
;
195 local_irq_save(flags
);
196 clist
= sd
->completion_queue
;
197 sd
->completion_queue
= NULL
;
198 local_irq_restore(flags
);
200 while (clist
!= NULL
) {
201 struct sk_buff
*skb
= clist
;
204 dev_kfree_skb_any(skb
); /* put this one back */
210 put_cpu_var(softnet_data
);
213 static struct sk_buff
* find_skb(struct netpoll
*np
, int len
, int reserve
)
215 int once
= 1, count
= 0;
217 struct sk_buff
*skb
= NULL
;
219 zap_completion_queue();
221 if (nr_skbs
< MAX_SKBS
)
224 skb
= alloc_skb(len
, GFP_ATOMIC
);
227 spin_lock_irqsave(&skb_list_lock
, flags
);
234 spin_unlock_irqrestore(&skb_list_lock
, flags
);
239 if (once
&& (count
== 1000000)) {
240 printk("out of netpoll skbs!\n");
247 atomic_set(&skb
->users
, 1);
248 skb_reserve(skb
, reserve
);
252 static void netpoll_send_skb(struct netpoll
*np
, struct sk_buff
*skb
)
255 struct netpoll_info
*npinfo
;
257 if (!np
|| !np
->dev
|| !netif_running(np
->dev
)) {
262 npinfo
= np
->dev
->npinfo
;
264 /* avoid recursion */
265 if (npinfo
->poll_owner
== smp_processor_id() ||
266 np
->dev
->xmit_lock_owner
== smp_processor_id()) {
276 netif_tx_lock(np
->dev
);
279 * network drivers do not expect to be called if the queue is
282 status
= NETDEV_TX_BUSY
;
283 if (!netif_queue_stopped(np
->dev
))
284 status
= np
->dev
->hard_start_xmit(skb
, np
->dev
);
286 netif_tx_unlock(np
->dev
);
290 npinfo
->tries
= MAX_RETRIES
; /* reset */
297 } while (npinfo
->tries
> 0);
300 void netpoll_send_udp(struct netpoll
*np
, const char *msg
, int len
)
302 int total_len
, eth_len
, ip_len
, udp_len
;
308 udp_len
= len
+ sizeof(*udph
);
309 ip_len
= eth_len
= udp_len
+ sizeof(*iph
);
310 total_len
= eth_len
+ ETH_HLEN
+ NET_IP_ALIGN
;
312 skb
= find_skb(np
, total_len
, total_len
- len
);
316 memcpy(skb
->data
, msg
, len
);
319 udph
= (struct udphdr
*) skb_push(skb
, sizeof(*udph
));
320 udph
->source
= htons(np
->local_port
);
321 udph
->dest
= htons(np
->remote_port
);
322 udph
->len
= htons(udp_len
);
325 iph
= (struct iphdr
*)skb_push(skb
, sizeof(*iph
));
327 /* iph->version = 4; iph->ihl = 5; */
328 put_unaligned(0x45, (unsigned char *)iph
);
330 put_unaligned(htons(ip_len
), &(iph
->tot_len
));
334 iph
->protocol
= IPPROTO_UDP
;
336 put_unaligned(htonl(np
->local_ip
), &(iph
->saddr
));
337 put_unaligned(htonl(np
->remote_ip
), &(iph
->daddr
));
338 iph
->check
= ip_fast_csum((unsigned char *)iph
, iph
->ihl
);
340 eth
= (struct ethhdr
*) skb_push(skb
, ETH_HLEN
);
342 eth
->h_proto
= htons(ETH_P_IP
);
343 memcpy(eth
->h_source
, np
->local_mac
, 6);
344 memcpy(eth
->h_dest
, np
->remote_mac
, 6);
348 netpoll_send_skb(np
, skb
);
351 static void arp_reply(struct sk_buff
*skb
)
353 struct netpoll_info
*npinfo
= skb
->dev
->npinfo
;
355 unsigned char *arp_ptr
;
356 int size
, type
= ARPOP_REPLY
, ptype
= ETH_P_ARP
;
358 struct sk_buff
*send_skb
;
359 struct netpoll
*np
= NULL
;
361 if (npinfo
->rx_np
&& npinfo
->rx_np
->dev
== skb
->dev
)
366 /* No arp on this interface */
367 if (skb
->dev
->flags
& IFF_NOARP
)
370 if (!pskb_may_pull(skb
, (sizeof(struct arphdr
) +
371 (2 * skb
->dev
->addr_len
) +
375 skb
->h
.raw
= skb
->nh
.raw
= skb
->data
;
378 if ((arp
->ar_hrd
!= htons(ARPHRD_ETHER
) &&
379 arp
->ar_hrd
!= htons(ARPHRD_IEEE802
)) ||
380 arp
->ar_pro
!= htons(ETH_P_IP
) ||
381 arp
->ar_op
!= htons(ARPOP_REQUEST
))
384 arp_ptr
= (unsigned char *)(arp
+1) + skb
->dev
->addr_len
;
385 memcpy(&sip
, arp_ptr
, 4);
386 arp_ptr
+= 4 + skb
->dev
->addr_len
;
387 memcpy(&tip
, arp_ptr
, 4);
389 /* Should we ignore arp? */
390 if (tip
!= htonl(np
->local_ip
) || LOOPBACK(tip
) || MULTICAST(tip
))
393 size
= sizeof(struct arphdr
) + 2 * (skb
->dev
->addr_len
+ 4);
394 send_skb
= find_skb(np
, size
+ LL_RESERVED_SPACE(np
->dev
),
395 LL_RESERVED_SPACE(np
->dev
));
400 send_skb
->nh
.raw
= send_skb
->data
;
401 arp
= (struct arphdr
*) skb_put(send_skb
, size
);
402 send_skb
->dev
= skb
->dev
;
403 send_skb
->protocol
= htons(ETH_P_ARP
);
405 /* Fill the device header for the ARP frame */
407 if (np
->dev
->hard_header
&&
408 np
->dev
->hard_header(send_skb
, skb
->dev
, ptype
,
409 np
->remote_mac
, np
->local_mac
,
410 send_skb
->len
) < 0) {
416 * Fill out the arp protocol part.
418 * we only support ethernet device type,
419 * which (according to RFC 1390) should always equal 1 (Ethernet).
422 arp
->ar_hrd
= htons(np
->dev
->type
);
423 arp
->ar_pro
= htons(ETH_P_IP
);
424 arp
->ar_hln
= np
->dev
->addr_len
;
426 arp
->ar_op
= htons(type
);
428 arp_ptr
=(unsigned char *)(arp
+ 1);
429 memcpy(arp_ptr
, np
->dev
->dev_addr
, np
->dev
->addr_len
);
430 arp_ptr
+= np
->dev
->addr_len
;
431 memcpy(arp_ptr
, &tip
, 4);
433 memcpy(arp_ptr
, np
->remote_mac
, np
->dev
->addr_len
);
434 arp_ptr
+= np
->dev
->addr_len
;
435 memcpy(arp_ptr
, &sip
, 4);
437 netpoll_send_skb(np
, send_skb
);
440 int __netpoll_rx(struct sk_buff
*skb
)
442 int proto
, len
, ulen
;
445 struct netpoll
*np
= skb
->dev
->npinfo
->rx_np
;
449 if (skb
->dev
->type
!= ARPHRD_ETHER
)
452 /* check if netpoll clients need ARP */
453 if (skb
->protocol
== __constant_htons(ETH_P_ARP
) &&
454 atomic_read(&trapped
)) {
459 proto
= ntohs(eth_hdr(skb
)->h_proto
);
460 if (proto
!= ETH_P_IP
)
462 if (skb
->pkt_type
== PACKET_OTHERHOST
)
467 iph
= (struct iphdr
*)skb
->data
;
468 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
470 if (iph
->ihl
< 5 || iph
->version
!= 4)
472 if (!pskb_may_pull(skb
, iph
->ihl
*4))
474 if (ip_fast_csum((u8
*)iph
, iph
->ihl
) != 0)
477 len
= ntohs(iph
->tot_len
);
478 if (skb
->len
< len
|| len
< iph
->ihl
*4)
481 if (iph
->protocol
!= IPPROTO_UDP
)
485 uh
= (struct udphdr
*)(((char *)iph
) + iph
->ihl
*4);
486 ulen
= ntohs(uh
->len
);
490 if (checksum_udp(skb
, uh
, ulen
, iph
->saddr
, iph
->daddr
))
492 if (np
->local_ip
&& np
->local_ip
!= ntohl(iph
->daddr
))
494 if (np
->remote_ip
&& np
->remote_ip
!= ntohl(iph
->saddr
))
496 if (np
->local_port
&& np
->local_port
!= ntohs(uh
->dest
))
499 np
->rx_hook(np
, ntohs(uh
->source
),
501 ulen
- sizeof(struct udphdr
));
507 if (atomic_read(&trapped
)) {
515 int netpoll_parse_options(struct netpoll
*np
, char *opt
)
517 char *cur
=opt
, *delim
;
520 if ((delim
= strchr(cur
, '@')) == NULL
)
523 np
->local_port
=simple_strtol(cur
, NULL
, 10);
527 printk(KERN_INFO
"%s: local port %d\n", np
->name
, np
->local_port
);
530 if ((delim
= strchr(cur
, '/')) == NULL
)
533 np
->local_ip
=ntohl(in_aton(cur
));
536 printk(KERN_INFO
"%s: local IP %d.%d.%d.%d\n",
537 np
->name
, HIPQUAD(np
->local_ip
));
542 /* parse out dev name */
543 if ((delim
= strchr(cur
, ',')) == NULL
)
546 strlcpy(np
->dev_name
, cur
, sizeof(np
->dev_name
));
551 printk(KERN_INFO
"%s: interface %s\n", np
->name
, np
->dev_name
);
555 if ((delim
= strchr(cur
, '@')) == NULL
)
558 np
->remote_port
=simple_strtol(cur
, NULL
, 10);
562 printk(KERN_INFO
"%s: remote port %d\n", np
->name
, np
->remote_port
);
565 if ((delim
= strchr(cur
, '/')) == NULL
)
568 np
->remote_ip
=ntohl(in_aton(cur
));
571 printk(KERN_INFO
"%s: remote IP %d.%d.%d.%d\n",
572 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
;
631 ndev
= dev_get_by_name(np
->dev_name
);
633 printk(KERN_ERR
"%s: %s doesn't exist, aborting.\n",
634 np
->name
, np
->dev_name
);
640 npinfo
= kmalloc(sizeof(*npinfo
), GFP_KERNEL
);
644 npinfo
->rx_flags
= 0;
645 npinfo
->rx_np
= NULL
;
646 spin_lock_init(&npinfo
->poll_lock
);
647 npinfo
->poll_owner
= -1;
648 npinfo
->tries
= MAX_RETRIES
;
649 spin_lock_init(&npinfo
->rx_lock
);
651 npinfo
= ndev
->npinfo
;
653 if (!ndev
->poll_controller
) {
654 printk(KERN_ERR
"%s: %s doesn't support polling, aborting.\n",
655 np
->name
, np
->dev_name
);
659 if (!netif_running(ndev
)) {
660 unsigned long atmost
, atleast
;
662 printk(KERN_INFO
"%s: device %s not up yet, forcing it\n",
663 np
->name
, np
->dev_name
);
666 if (dev_change_flags(ndev
, ndev
->flags
| IFF_UP
) < 0) {
667 printk(KERN_ERR
"%s: failed to open %s\n",
668 np
->name
, np
->dev_name
);
674 atleast
= jiffies
+ HZ
/10;
675 atmost
= jiffies
+ 4*HZ
;
676 while (!netif_carrier_ok(ndev
)) {
677 if (time_after(jiffies
, atmost
)) {
679 "%s: timeout waiting for carrier\n",
686 /* If carrier appears to come up instantly, we don't
687 * trust it and pause so that we don't pump all our
688 * queued console messages into the bitbucket.
691 if (time_before(jiffies
, atleast
)) {
692 printk(KERN_NOTICE
"%s: carrier detect appears"
693 " untrustworthy, waiting 4 seconds\n",
699 if (is_zero_ether_addr(np
->local_mac
) && ndev
->dev_addr
)
700 memcpy(np
->local_mac
, ndev
->dev_addr
, 6);
704 in_dev
= __in_dev_get_rcu(ndev
);
706 if (!in_dev
|| !in_dev
->ifa_list
) {
708 printk(KERN_ERR
"%s: no IP address for %s, aborting\n",
709 np
->name
, np
->dev_name
);
713 np
->local_ip
= ntohl(in_dev
->ifa_list
->ifa_local
);
715 printk(KERN_INFO
"%s: local IP %d.%d.%d.%d\n",
716 np
->name
, HIPQUAD(np
->local_ip
));
720 spin_lock_irqsave(&npinfo
->rx_lock
, flags
);
721 npinfo
->rx_flags
|= NETPOLL_RX_ENABLED
;
723 spin_unlock_irqrestore(&npinfo
->rx_lock
, flags
);
726 /* fill up the skb queue */
729 /* last thing to do is link it to the net device structure */
730 ndev
->npinfo
= npinfo
;
732 /* avoid racing with NAPI reading npinfo */
745 void netpoll_cleanup(struct netpoll
*np
)
747 struct netpoll_info
*npinfo
;
751 npinfo
= np
->dev
->npinfo
;
752 if (npinfo
&& npinfo
->rx_np
== np
) {
753 spin_lock_irqsave(&npinfo
->rx_lock
, flags
);
754 npinfo
->rx_np
= NULL
;
755 npinfo
->rx_flags
&= ~NETPOLL_RX_ENABLED
;
756 spin_unlock_irqrestore(&npinfo
->rx_lock
, flags
);
764 int netpoll_trap(void)
766 return atomic_read(&trapped
);
769 void netpoll_set_trap(int trap
)
772 atomic_inc(&trapped
);
774 atomic_dec(&trapped
);
777 EXPORT_SYMBOL(netpoll_set_trap
);
778 EXPORT_SYMBOL(netpoll_trap
);
779 EXPORT_SYMBOL(netpoll_parse_options
);
780 EXPORT_SYMBOL(netpoll_setup
);
781 EXPORT_SYMBOL(netpoll_cleanup
);
782 EXPORT_SYMBOL(netpoll_send_udp
);
783 EXPORT_SYMBOL(netpoll_poll
);
784 EXPORT_SYMBOL(netpoll_queue
);
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