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/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 DEFINE_SPINLOCK(skb_list_lock);
39 static struct sk_buff *skbs;
41 static DEFINE_SPINLOCK(queue_lock);
42 static int queue_depth;
43 static struct sk_buff *queue_head, *queue_tail;
45 static atomic_t trapped;
47 #define NETPOLL_RX_ENABLED 1
48 #define NETPOLL_RX_DROP 2
50 #define MAX_SKB_SIZE \
51 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
52 sizeof(struct iphdr) + sizeof(struct ethhdr))
54 static void zap_completion_queue(void);
56 static void queue_process(void *p)
62 spin_lock_irqsave(&queue_lock, flags);
65 queue_head = skb->next;
66 if (skb == queue_tail)
71 spin_unlock_irqrestore(&queue_lock, flags);
77 static DECLARE_WORK(send_queue, queue_process, NULL);
79 void netpoll_queue(struct sk_buff *skb)
83 if (queue_depth == MAX_QUEUE_DEPTH) {
88 spin_lock_irqsave(&queue_lock, flags);
92 queue_tail->next = skb;
95 spin_unlock_irqrestore(&queue_lock, flags);
97 schedule_work(&send_queue);
100 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
101 unsigned short ulen, u32 saddr, u32 daddr)
106 if (skb->ip_summed == CHECKSUM_HW)
107 return csum_tcpudp_magic(
108 saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
110 skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
112 return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
116 * Check whether delayed processing was scheduled for our NIC. If so,
117 * we attempt to grab the poll lock and use ->poll() to pump the card.
118 * If this fails, either we've recursed in ->poll() or it's already
119 * running on another CPU.
121 * Note: we don't mask interrupts with this lock because we're using
122 * trylock here and interrupts are already disabled in the softirq
123 * case. Further, we test the poll_owner to avoid recursion on UP
124 * systems where the lock doesn't exist.
126 * In cases where there is bi-directional communications, reading only
127 * one message at a time can lead to packets being dropped by the
128 * network adapter, forcing superfluous retries and possibly timeouts.
129 * Thus, we set our budget to greater than 1.
131 static void poll_napi(struct netpoll *np)
135 if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
136 np->poll_owner != smp_processor_id() &&
137 spin_trylock(&np->poll_lock)) {
138 np->rx_flags |= NETPOLL_RX_DROP;
139 atomic_inc(&trapped);
141 np->dev->poll(np->dev, &budget);
143 atomic_dec(&trapped);
144 np->rx_flags &= ~NETPOLL_RX_DROP;
145 spin_unlock(&np->poll_lock);
149 void netpoll_poll(struct netpoll *np)
151 if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
154 /* Process pending work on NIC */
155 np->dev->poll_controller(np->dev);
159 zap_completion_queue();
162 static void refill_skbs(void)
167 spin_lock_irqsave(&skb_list_lock, flags);
168 while (nr_skbs < MAX_SKBS) {
169 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
177 spin_unlock_irqrestore(&skb_list_lock, flags);
180 static void zap_completion_queue(void)
183 struct softnet_data *sd = &get_cpu_var(softnet_data);
185 if (sd->completion_queue) {
186 struct sk_buff *clist;
188 local_irq_save(flags);
189 clist = sd->completion_queue;
190 sd->completion_queue = NULL;
191 local_irq_restore(flags);
193 while (clist != NULL) {
194 struct sk_buff *skb = clist;
197 dev_kfree_skb_any(skb); /* put this one back */
203 put_cpu_var(softnet_data);
206 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
208 int once = 1, count = 0;
210 struct sk_buff *skb = NULL;
212 zap_completion_queue();
214 if (nr_skbs < MAX_SKBS)
217 skb = alloc_skb(len, GFP_ATOMIC);
220 spin_lock_irqsave(&skb_list_lock, flags);
227 spin_unlock_irqrestore(&skb_list_lock, flags);
232 if (once && (count == 1000000)) {
233 printk("out of netpoll skbs!\n");
240 atomic_set(&skb->users, 1);
241 skb_reserve(skb, reserve);
245 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
250 if(!np || !np->dev || !netif_running(np->dev)) {
255 /* avoid recursion */
256 if(np->poll_owner == smp_processor_id() ||
257 np->dev->xmit_lock_owner == smp_processor_id()) {
265 spin_lock(&np->dev->xmit_lock);
266 np->dev->xmit_lock_owner = smp_processor_id();
269 * network drivers do not expect to be called if the queue is
272 if (netif_queue_stopped(np->dev)) {
273 np->dev->xmit_lock_owner = -1;
274 spin_unlock(&np->dev->xmit_lock);
280 status = np->dev->hard_start_xmit(skb, np->dev);
281 np->dev->xmit_lock_owner = -1;
282 spin_unlock(&np->dev->xmit_lock);
291 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
293 int total_len, eth_len, ip_len, udp_len;
299 udp_len = len + sizeof(*udph);
300 ip_len = eth_len = udp_len + sizeof(*iph);
301 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
303 skb = find_skb(np, total_len, total_len - len);
307 memcpy(skb->data, msg, len);
310 udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
311 udph->source = htons(np->local_port);
312 udph->dest = htons(np->remote_port);
313 udph->len = htons(udp_len);
316 iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
318 /* iph->version = 4; iph->ihl = 5; */
319 put_unaligned(0x45, (unsigned char *)iph);
321 put_unaligned(htons(ip_len), &(iph->tot_len));
325 iph->protocol = IPPROTO_UDP;
327 put_unaligned(htonl(np->local_ip), &(iph->saddr));
328 put_unaligned(htonl(np->remote_ip), &(iph->daddr));
329 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
331 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
333 eth->h_proto = htons(ETH_P_IP);
334 memcpy(eth->h_source, np->local_mac, 6);
335 memcpy(eth->h_dest, np->remote_mac, 6);
339 netpoll_send_skb(np, skb);
342 static void arp_reply(struct sk_buff *skb)
345 unsigned char *arp_ptr;
346 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
348 struct sk_buff *send_skb;
349 struct netpoll *np = skb->dev->np;
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->h.raw = skb->nh.raw = skb->data;
365 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
366 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
367 arp->ar_pro != htons(ETH_P_IP) ||
368 arp->ar_op != htons(ARPOP_REQUEST))
371 arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
372 memcpy(&sip, arp_ptr, 4);
373 arp_ptr += 4 + skb->dev->addr_len;
374 memcpy(&tip, arp_ptr, 4);
376 /* Should we ignore arp? */
377 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
380 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
381 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
382 LL_RESERVED_SPACE(np->dev));
387 send_skb->nh.raw = send_skb->data;
388 arp = (struct arphdr *) skb_put(send_skb, size);
389 send_skb->dev = skb->dev;
390 send_skb->protocol = htons(ETH_P_ARP);
392 /* Fill the device header for the ARP frame */
394 if (np->dev->hard_header &&
395 np->dev->hard_header(send_skb, skb->dev, ptype,
396 np->remote_mac, np->local_mac,
397 send_skb->len) < 0) {
403 * Fill out the arp protocol part.
405 * we only support ethernet device type,
406 * which (according to RFC 1390) should always equal 1 (Ethernet).
409 arp->ar_hrd = htons(np->dev->type);
410 arp->ar_pro = htons(ETH_P_IP);
411 arp->ar_hln = np->dev->addr_len;
413 arp->ar_op = htons(type);
415 arp_ptr=(unsigned char *)(arp + 1);
416 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
417 arp_ptr += np->dev->addr_len;
418 memcpy(arp_ptr, &tip, 4);
420 memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
421 arp_ptr += np->dev->addr_len;
422 memcpy(arp_ptr, &sip, 4);
424 netpoll_send_skb(np, send_skb);
427 int __netpoll_rx(struct sk_buff *skb)
429 int proto, len, ulen;
432 struct netpoll *np = skb->dev->np;
436 if (skb->dev->type != ARPHRD_ETHER)
439 /* check if netpoll clients need ARP */
440 if (skb->protocol == __constant_htons(ETH_P_ARP) &&
441 atomic_read(&trapped)) {
446 proto = ntohs(eth_hdr(skb)->h_proto);
447 if (proto != ETH_P_IP)
449 if (skb->pkt_type == PACKET_OTHERHOST)
454 iph = (struct iphdr *)skb->data;
455 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
457 if (iph->ihl < 5 || iph->version != 4)
459 if (!pskb_may_pull(skb, iph->ihl*4))
461 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
464 len = ntohs(iph->tot_len);
465 if (skb->len < len || len < iph->ihl*4)
468 if (iph->protocol != IPPROTO_UDP)
472 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
473 ulen = ntohs(uh->len);
477 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
479 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
481 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
483 if (np->local_port && np->local_port != ntohs(uh->dest))
486 np->rx_hook(np, ntohs(uh->source),
488 ulen - sizeof(struct udphdr));
494 if (atomic_read(&trapped)) {
502 int netpoll_parse_options(struct netpoll *np, char *opt)
504 char *cur=opt, *delim;
507 if ((delim = strchr(cur, '@')) == NULL)
510 np->local_port=simple_strtol(cur, NULL, 10);
514 printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
517 if ((delim = strchr(cur, '/')) == NULL)
520 np->local_ip=ntohl(in_aton(cur));
523 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
524 np->name, HIPQUAD(np->local_ip));
529 /* parse out dev name */
530 if ((delim = strchr(cur, ',')) == NULL)
533 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
538 printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
542 if ((delim = strchr(cur, '@')) == NULL)
545 np->remote_port=simple_strtol(cur, NULL, 10);
549 printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
552 if ((delim = strchr(cur, '/')) == NULL)
555 np->remote_ip=ntohl(in_aton(cur));
558 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
559 np->name, HIPQUAD(np->remote_ip));
564 if ((delim = strchr(cur, ':')) == NULL)
567 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
569 if ((delim = strchr(cur, ':')) == NULL)
572 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
574 if ((delim = strchr(cur, ':')) == NULL)
577 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
579 if ((delim = strchr(cur, ':')) == NULL)
582 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
584 if ((delim = strchr(cur, ':')) == NULL)
587 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
589 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
592 printk(KERN_INFO "%s: remote ethernet address "
593 "%02x:%02x:%02x:%02x:%02x:%02x\n",
605 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
610 int netpoll_setup(struct netpoll *np)
612 struct net_device *ndev = NULL;
613 struct in_device *in_dev;
615 np->poll_lock = SPIN_LOCK_UNLOCKED;
619 ndev = dev_get_by_name(np->dev_name);
621 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
622 np->name, np->dev_name);
629 if (!ndev->poll_controller) {
630 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
631 np->name, np->dev_name);
635 if (!netif_running(ndev)) {
636 unsigned long atmost, atleast;
638 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
639 np->name, np->dev_name);
642 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
643 printk(KERN_ERR "%s: failed to open %s\n",
644 np->name, np->dev_name);
650 atleast = jiffies + HZ/10;
651 atmost = jiffies + 4*HZ;
652 while (!netif_carrier_ok(ndev)) {
653 if (time_after(jiffies, atmost)) {
655 "%s: timeout waiting for carrier\n",
662 /* If carrier appears to come up instantly, we don't
663 * trust it and pause so that we don't pump all our
664 * queued console messages into the bitbucket.
667 if (time_before(jiffies, atleast)) {
668 printk(KERN_NOTICE "%s: carrier detect appears"
669 " untrustworthy, waiting 4 seconds\n",
675 if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
676 memcpy(np->local_mac, ndev->dev_addr, 6);
680 in_dev = __in_dev_get(ndev);
682 if (!in_dev || !in_dev->ifa_list) {
684 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
685 np->name, np->dev_name);
689 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
691 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
692 np->name, HIPQUAD(np->local_ip));
696 np->rx_flags = NETPOLL_RX_ENABLED;
707 void netpoll_cleanup(struct netpoll *np)
715 int netpoll_trap(void)
717 return atomic_read(&trapped);
720 void netpoll_set_trap(int trap)
723 atomic_inc(&trapped);
725 atomic_dec(&trapped);
728 EXPORT_SYMBOL(netpoll_set_trap);
729 EXPORT_SYMBOL(netpoll_trap);
730 EXPORT_SYMBOL(netpoll_parse_options);
731 EXPORT_SYMBOL(netpoll_setup);
732 EXPORT_SYMBOL(netpoll_cleanup);
733 EXPORT_SYMBOL(netpoll_send_udp);
734 EXPORT_SYMBOL(netpoll_poll);
735 EXPORT_SYMBOL(netpoll_queue);