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);