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 struct sk_buff_head skb_pool;
41 static atomic_t trapped;
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(void *p)
55 struct netpoll_info *npinfo = p;
58 while ((skb = skb_dequeue(&npinfo->txq)))
63 void netpoll_queue(struct sk_buff *skb)
65 struct net_device *dev = skb->dev;
66 struct netpoll_info *npinfo = dev->npinfo;
71 skb_queue_tail(&npinfo->txq, skb);
72 schedule_work(&npinfo->tx_work);
76 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
77 unsigned short ulen, u32 saddr, u32 daddr)
81 if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
84 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
86 if (skb->ip_summed == CHECKSUM_COMPLETE &&
87 !(u16)csum_fold(csum_add(psum, skb->csum)))
92 return __skb_checksum_complete(skb);
96 * Check whether delayed processing was scheduled for our NIC. If so,
97 * we attempt to grab the poll lock and use ->poll() to pump the card.
98 * If this fails, either we've recursed in ->poll() or it's already
99 * running on another CPU.
101 * Note: we don't mask interrupts with this lock because we're using
102 * trylock here and interrupts are already disabled in the softirq
103 * case. Further, we test the poll_owner to avoid recursion on UP
104 * systems where the lock doesn't exist.
106 * In cases where there is bi-directional communications, reading only
107 * one message at a time can lead to packets being dropped by the
108 * network adapter, forcing superfluous retries and possibly timeouts.
109 * Thus, we set our budget to greater than 1.
111 static void poll_napi(struct netpoll *np)
113 struct netpoll_info *npinfo = np->dev->npinfo;
116 if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
117 npinfo->poll_owner != smp_processor_id() &&
118 spin_trylock(&npinfo->poll_lock)) {
119 npinfo->rx_flags |= NETPOLL_RX_DROP;
120 atomic_inc(&trapped);
122 np->dev->poll(np->dev, &budget);
124 atomic_dec(&trapped);
125 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
126 spin_unlock(&npinfo->poll_lock);
130 static void service_arp_queue(struct netpoll_info *npi)
137 skb = skb_dequeue(&npi->arp_tx);
139 while (skb != NULL) {
141 skb = skb_dequeue(&npi->arp_tx);
146 void netpoll_poll(struct netpoll *np)
148 if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
151 /* Process pending work on NIC */
152 np->dev->poll_controller(np->dev);
156 service_arp_queue(np->dev->npinfo);
158 zap_completion_queue();
161 static void refill_skbs(void)
166 spin_lock_irqsave(&skb_pool.lock, flags);
167 while (skb_pool.qlen < MAX_SKBS) {
168 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
172 __skb_queue_tail(&skb_pool, skb);
174 spin_unlock_irqrestore(&skb_pool.lock, flags);
177 static void zap_completion_queue(void)
180 struct softnet_data *sd = &get_cpu_var(softnet_data);
182 if (sd->completion_queue) {
183 struct sk_buff *clist;
185 local_irq_save(flags);
186 clist = sd->completion_queue;
187 sd->completion_queue = NULL;
188 local_irq_restore(flags);
190 while (clist != NULL) {
191 struct sk_buff *skb = clist;
194 dev_kfree_skb_any(skb); /* put this one back */
200 put_cpu_var(softnet_data);
203 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
208 zap_completion_queue();
212 skb = alloc_skb(len, GFP_ATOMIC);
214 skb = skb_dequeue(&skb_pool);
224 atomic_set(&skb->users, 1);
225 skb_reserve(skb, reserve);
229 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
232 struct netpoll_info *npinfo;
234 if (!np || !np->dev || !netif_running(np->dev)) {
239 npinfo = np->dev->npinfo;
241 /* avoid recursion */
242 if (npinfo->poll_owner == smp_processor_id() ||
243 np->dev->xmit_lock_owner == smp_processor_id()) {
253 netif_tx_lock(np->dev);
256 * network drivers do not expect to be called if the queue is
259 status = NETDEV_TX_BUSY;
260 if (!netif_queue_stopped(np->dev))
261 status = np->dev->hard_start_xmit(skb, np->dev);
263 netif_tx_unlock(np->dev);
267 npinfo->tries = MAX_RETRIES; /* reset */
274 } while (npinfo->tries > 0);
277 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
279 int total_len, eth_len, ip_len, udp_len;
285 udp_len = len + sizeof(*udph);
286 ip_len = eth_len = udp_len + sizeof(*iph);
287 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
289 skb = find_skb(np, total_len, total_len - len);
293 memcpy(skb->data, msg, len);
296 skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
297 udph->source = htons(np->local_port);
298 udph->dest = htons(np->remote_port);
299 udph->len = htons(udp_len);
301 udph->check = csum_tcpudp_magic(htonl(np->local_ip),
302 htonl(np->remote_ip),
303 udp_len, IPPROTO_UDP,
304 csum_partial((unsigned char *)udph, udp_len, 0));
305 if (udph->check == 0)
308 skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
310 /* iph->version = 4; iph->ihl = 5; */
311 put_unaligned(0x45, (unsigned char *)iph);
313 put_unaligned(htons(ip_len), &(iph->tot_len));
317 iph->protocol = IPPROTO_UDP;
319 put_unaligned(htonl(np->local_ip), &(iph->saddr));
320 put_unaligned(htonl(np->remote_ip), &(iph->daddr));
321 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
323 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
324 skb->mac.raw = skb->data;
325 skb->protocol = eth->h_proto = htons(ETH_P_IP);
326 memcpy(eth->h_source, np->local_mac, 6);
327 memcpy(eth->h_dest, np->remote_mac, 6);
331 netpoll_send_skb(np, skb);
334 static void arp_reply(struct sk_buff *skb)
336 struct netpoll_info *npinfo = skb->dev->npinfo;
338 unsigned char *arp_ptr;
339 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
341 struct sk_buff *send_skb;
342 struct netpoll *np = NULL;
344 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
349 /* No arp on this interface */
350 if (skb->dev->flags & IFF_NOARP)
353 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
354 (2 * skb->dev->addr_len) +
358 skb->h.raw = skb->nh.raw = skb->data;
361 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
362 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
363 arp->ar_pro != htons(ETH_P_IP) ||
364 arp->ar_op != htons(ARPOP_REQUEST))
367 arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
368 memcpy(&sip, arp_ptr, 4);
369 arp_ptr += 4 + skb->dev->addr_len;
370 memcpy(&tip, arp_ptr, 4);
372 /* Should we ignore arp? */
373 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
376 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
377 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
378 LL_RESERVED_SPACE(np->dev));
383 send_skb->nh.raw = send_skb->data;
384 arp = (struct arphdr *) skb_put(send_skb, size);
385 send_skb->dev = skb->dev;
386 send_skb->protocol = htons(ETH_P_ARP);
388 /* Fill the device header for the ARP frame */
390 if (np->dev->hard_header &&
391 np->dev->hard_header(send_skb, skb->dev, ptype,
392 np->remote_mac, np->local_mac,
393 send_skb->len) < 0) {
399 * Fill out the arp protocol part.
401 * we only support ethernet device type,
402 * which (according to RFC 1390) should always equal 1 (Ethernet).
405 arp->ar_hrd = htons(np->dev->type);
406 arp->ar_pro = htons(ETH_P_IP);
407 arp->ar_hln = np->dev->addr_len;
409 arp->ar_op = htons(type);
411 arp_ptr=(unsigned char *)(arp + 1);
412 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
413 arp_ptr += np->dev->addr_len;
414 memcpy(arp_ptr, &tip, 4);
416 memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
417 arp_ptr += np->dev->addr_len;
418 memcpy(arp_ptr, &sip, 4);
420 netpoll_send_skb(np, send_skb);
423 int __netpoll_rx(struct sk_buff *skb)
425 int proto, len, ulen;
428 struct netpoll_info *npi = skb->dev->npinfo;
429 struct netpoll *np = npi->rx_np;
434 if (skb->dev->type != ARPHRD_ETHER)
437 /* check if netpoll clients need ARP */
438 if (skb->protocol == __constant_htons(ETH_P_ARP) &&
439 atomic_read(&trapped)) {
440 skb_queue_tail(&npi->arp_tx, skb);
444 proto = ntohs(eth_hdr(skb)->h_proto);
445 if (proto != ETH_P_IP)
447 if (skb->pkt_type == PACKET_OTHERHOST)
452 iph = (struct iphdr *)skb->data;
453 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
455 if (iph->ihl < 5 || iph->version != 4)
457 if (!pskb_may_pull(skb, iph->ihl*4))
459 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
462 len = ntohs(iph->tot_len);
463 if (skb->len < len || len < iph->ihl*4)
466 if (iph->protocol != IPPROTO_UDP)
470 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
471 ulen = ntohs(uh->len);
475 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
477 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
479 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
481 if (np->local_port && np->local_port != ntohs(uh->dest))
484 np->rx_hook(np, ntohs(uh->source),
486 ulen - sizeof(struct udphdr));
492 if (atomic_read(&trapped)) {
500 int netpoll_parse_options(struct netpoll *np, char *opt)
502 char *cur=opt, *delim;
505 if ((delim = strchr(cur, '@')) == NULL)
508 np->local_port=simple_strtol(cur, NULL, 10);
512 printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
515 if ((delim = strchr(cur, '/')) == NULL)
518 np->local_ip=ntohl(in_aton(cur));
521 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
522 np->name, HIPQUAD(np->local_ip));
527 /* parse out dev name */
528 if ((delim = strchr(cur, ',')) == NULL)
531 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
536 printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
540 if ((delim = strchr(cur, '@')) == NULL)
543 np->remote_port=simple_strtol(cur, NULL, 10);
547 printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
550 if ((delim = strchr(cur, '/')) == NULL)
553 np->remote_ip=ntohl(in_aton(cur));
556 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
557 np->name, HIPQUAD(np->remote_ip));
562 if ((delim = strchr(cur, ':')) == NULL)
565 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
567 if ((delim = strchr(cur, ':')) == NULL)
570 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
572 if ((delim = strchr(cur, ':')) == NULL)
575 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
577 if ((delim = strchr(cur, ':')) == NULL)
580 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
582 if ((delim = strchr(cur, ':')) == NULL)
585 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
587 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
590 printk(KERN_INFO "%s: remote ethernet address "
591 "%02x:%02x:%02x:%02x:%02x:%02x\n",
603 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
608 int netpoll_setup(struct netpoll *np)
610 struct net_device *ndev = NULL;
611 struct in_device *in_dev;
612 struct netpoll_info *npinfo;
616 ndev = dev_get_by_name(np->dev_name);
618 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
619 np->name, np->dev_name);
625 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
629 npinfo->rx_flags = 0;
630 npinfo->rx_np = NULL;
631 spin_lock_init(&npinfo->poll_lock);
632 npinfo->poll_owner = -1;
633 npinfo->tries = MAX_RETRIES;
634 spin_lock_init(&npinfo->rx_lock);
635 skb_queue_head_init(&npinfo->arp_tx);
636 skb_queue_head_init(&npinfo->txq);
637 INIT_WORK(&npinfo->tx_work, queue_process, npinfo);
639 atomic_set(&npinfo->refcnt, 1);
641 npinfo = ndev->npinfo;
642 atomic_inc(&npinfo->refcnt);
645 if (!ndev->poll_controller) {
646 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
647 np->name, np->dev_name);
651 if (!netif_running(ndev)) {
652 unsigned long atmost, atleast;
654 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
655 np->name, np->dev_name);
658 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
659 printk(KERN_ERR "%s: failed to open %s\n",
660 np->name, np->dev_name);
666 atleast = jiffies + HZ/10;
667 atmost = jiffies + 4*HZ;
668 while (!netif_carrier_ok(ndev)) {
669 if (time_after(jiffies, atmost)) {
671 "%s: timeout waiting for carrier\n",
678 /* If carrier appears to come up instantly, we don't
679 * trust it and pause so that we don't pump all our
680 * queued console messages into the bitbucket.
683 if (time_before(jiffies, atleast)) {
684 printk(KERN_NOTICE "%s: carrier detect appears"
685 " untrustworthy, waiting 4 seconds\n",
691 if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
692 memcpy(np->local_mac, ndev->dev_addr, 6);
696 in_dev = __in_dev_get_rcu(ndev);
698 if (!in_dev || !in_dev->ifa_list) {
700 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
701 np->name, np->dev_name);
705 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
707 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
708 np->name, HIPQUAD(np->local_ip));
712 spin_lock_irqsave(&npinfo->rx_lock, flags);
713 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
715 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
718 /* fill up the skb queue */
721 /* last thing to do is link it to the net device structure */
722 ndev->npinfo = npinfo;
724 /* avoid racing with NAPI reading npinfo */
737 static int __init netpoll_init(void) {
738 skb_queue_head_init(&skb_pool);
741 core_initcall(netpoll_init);
743 void netpoll_cleanup(struct netpoll *np)
745 struct netpoll_info *npinfo;
749 npinfo = np->dev->npinfo;
751 if (npinfo->rx_np == np) {
752 spin_lock_irqsave(&npinfo->rx_lock, flags);
753 npinfo->rx_np = NULL;
754 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
755 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
758 np->dev->npinfo = NULL;
759 if (atomic_dec_and_test(&npinfo->refcnt)) {
760 skb_queue_purge(&npinfo->arp_tx);
761 skb_queue_purge(&npinfo->txq);
762 flush_scheduled_work();
774 int netpoll_trap(void)
776 return atomic_read(&trapped);
779 void netpoll_set_trap(int trap)
782 atomic_inc(&trapped);
784 atomic_dec(&trapped);
787 EXPORT_SYMBOL(netpoll_set_trap);
788 EXPORT_SYMBOL(netpoll_trap);
789 EXPORT_SYMBOL(netpoll_parse_options);
790 EXPORT_SYMBOL(netpoll_setup);
791 EXPORT_SYMBOL(netpoll_cleanup);
792 EXPORT_SYMBOL(netpoll_send_udp);
793 EXPORT_SYMBOL(netpoll_poll);
794 EXPORT_SYMBOL(netpoll_queue);