[mirror_ubuntu-zesty-kernel.git] / net / core / netpoll.c

/*
 * Common framework for low-level network console, dump, and debugger code
 *
 * Sep 8 2003  Matt Mackall <mpm@selenic.com>
 *
 * based on the netconsole code from:
 *
 * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
 * Copyright (C) 2002  Red Hat, Inc.
 */

#include <linux/smp_lock.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/string.h>
#include <linux/inetdevice.h>
#include <linux/inet.h>
#include <linux/interrupt.h>
#include <linux/netpoll.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <asm/unaligned.h>

/*
 * We maintain a small pool of fully-sized skbs, to make sure the
 * message gets out even in extreme OOM situations.
 */

#define MAX_UDP_CHUNK 1460
#define MAX_SKBS 32
#define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
#define MAX_RETRIES 20000

static DEFINE_SPINLOCK(skb_list_lock);
static int nr_skbs;
static struct sk_buff *skbs;

static DEFINE_SPINLOCK(queue_lock);
static int queue_depth;
static struct sk_buff *queue_head, *queue_tail;

static atomic_t trapped;

#define NETPOLL_RX_ENABLED  1
#define NETPOLL_RX_DROP     2

#define MAX_SKB_SIZE \
		(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
				sizeof(struct iphdr) + sizeof(struct ethhdr))

static void zap_completion_queue(void);

static void queue_process(void *p)
{
	unsigned long flags;
	struct sk_buff *skb;

	while (queue_head) {
		spin_lock_irqsave(&queue_lock, flags);

		skb = queue_head;
		queue_head = skb->next;
		if (skb == queue_tail)
			queue_head = NULL;

		queue_depth--;

		spin_unlock_irqrestore(&queue_lock, flags);

		dev_queue_xmit(skb);
	}
}

static DECLARE_WORK(send_queue, queue_process, NULL);

void netpoll_queue(struct sk_buff *skb)
{
	unsigned long flags;

	if (queue_depth == MAX_QUEUE_DEPTH) {
		__kfree_skb(skb);
		return;
	}

	spin_lock_irqsave(&queue_lock, flags);
	if (!queue_head)
		queue_head = skb;
	else
		queue_tail->next = skb;
	queue_tail = skb;
	queue_depth++;
	spin_unlock_irqrestore(&queue_lock, flags);

	schedule_work(&send_queue);
}

static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
			     unsigned short ulen, u32 saddr, u32 daddr)
{
	if (uh->check == 0)
		return 0;

	if (skb->ip_summed == CHECKSUM_HW)
		return csum_tcpudp_magic(
			saddr, daddr, ulen, IPPROTO_UDP, skb->csum);

	skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);

	return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
}

/*
 * Check whether delayed processing was scheduled for our NIC. If so,
 * we attempt to grab the poll lock and use ->poll() to pump the card.
 * If this fails, either we've recursed in ->poll() or it's already
 * running on another CPU.
 *
 * Note: we don't mask interrupts with this lock because we're using
 * trylock here and interrupts are already disabled in the softirq
 * case. Further, we test the poll_owner to avoid recursion on UP
 * systems where the lock doesn't exist.
 *
 * In cases where there is bi-directional communications, reading only
 * one message at a time can lead to packets being dropped by the
 * network adapter, forcing superfluous retries and possibly timeouts.
 * Thus, we set our budget to greater than 1.
 */
static void poll_napi(struct netpoll *np)
{
	struct netpoll_info *npinfo = np->dev->npinfo;
	int budget = 16;

	if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
	    npinfo->poll_owner != smp_processor_id() &&
	    spin_trylock(&npinfo->poll_lock)) {
		npinfo->rx_flags |= NETPOLL_RX_DROP;
		atomic_inc(&trapped);

		np->dev->poll(np->dev, &budget);

		atomic_dec(&trapped);
		npinfo->rx_flags &= ~NETPOLL_RX_DROP;
		spin_unlock(&npinfo->poll_lock);
	}
}

void netpoll_poll(struct netpoll *np)
{
	if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
		return;

	/* Process pending work on NIC */
	np->dev->poll_controller(np->dev);
	if (np->dev->poll)
		poll_napi(np);

	zap_completion_queue();
}

static void refill_skbs(void)
{
	struct sk_buff *skb;
	unsigned long flags;

	spin_lock_irqsave(&skb_list_lock, flags);
	while (nr_skbs < MAX_SKBS) {
		skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
		if (!skb)
			break;

		skb->next = skbs;
		skbs = skb;
		nr_skbs++;
	}
	spin_unlock_irqrestore(&skb_list_lock, flags);
}

static void zap_completion_queue(void)
{
	unsigned long flags;
	struct softnet_data *sd = &get_cpu_var(softnet_data);

	if (sd->completion_queue) {
		struct sk_buff *clist;

		local_irq_save(flags);
		clist = sd->completion_queue;
		sd->completion_queue = NULL;
		local_irq_restore(flags);

		while (clist != NULL) {
			struct sk_buff *skb = clist;
			clist = clist->next;
			if(skb->destructor)
				dev_kfree_skb_any(skb); /* put this one back */
			else
				__kfree_skb(skb);
		}
	}

	put_cpu_var(softnet_data);
}

static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
{
	int once = 1, count = 0;
	unsigned long flags;
	struct sk_buff *skb = NULL;

	zap_completion_queue();
repeat:
	if (nr_skbs < MAX_SKBS)
		refill_skbs();

	skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb) {
		spin_lock_irqsave(&skb_list_lock, flags);
		skb = skbs;
		if (skb) {
			skbs = skb->next;
			skb->next = NULL;
			nr_skbs--;
		}
		spin_unlock_irqrestore(&skb_list_lock, flags);
	}

	if(!skb) {
		count++;
		if (once && (count == 1000000)) {
			printk("out of netpoll skbs!\n");
			once = 0;
		}
		netpoll_poll(np);
		goto repeat;
	}

	atomic_set(&skb->users, 1);
	skb_reserve(skb, reserve);
	return skb;
}

static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
	int status;
	struct netpoll_info *npinfo;

	if (!np || !np->dev || !netif_running(np->dev)) {
		__kfree_skb(skb);
		return;
	}

	npinfo = np->dev->npinfo;

	/* avoid recursion */
	if (npinfo->poll_owner == smp_processor_id() ||
	    np->dev->xmit_lock_owner == smp_processor_id()) {
		if (np->drop)
			np->drop(skb);
		else
			__kfree_skb(skb);
		return;
	}

	do {
		npinfo->tries--;
		spin_lock(&np->dev->xmit_lock);
		np->dev->xmit_lock_owner = smp_processor_id();

		/*
		 * network drivers do not expect to be called if the queue is
		 * stopped.
		 */
		if (netif_queue_stopped(np->dev)) {
			np->dev->xmit_lock_owner = -1;
			spin_unlock(&np->dev->xmit_lock);
			netpoll_poll(np);
			udelay(50);
			continue;
		}

		status = np->dev->hard_start_xmit(skb, np->dev);
		np->dev->xmit_lock_owner = -1;
		spin_unlock(&np->dev->xmit_lock);

		/* success */
		if(!status) {
			npinfo->tries = MAX_RETRIES; /* reset */
			return;
		}

		/* transmit busy */
		netpoll_poll(np);
		udelay(50);
	} while (npinfo->tries > 0);
}

void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
{
	int total_len, eth_len, ip_len, udp_len;
	struct sk_buff *skb;
	struct udphdr *udph;
	struct iphdr *iph;
	struct ethhdr *eth;

	udp_len = len + sizeof(*udph);
	ip_len = eth_len = udp_len + sizeof(*iph);
	total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;

	skb = find_skb(np, total_len, total_len - len);
	if (!skb)
		return;

	memcpy(skb->data, msg, len);
	skb->len += len;

	udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
	udph->source = htons(np->local_port);
	udph->dest = htons(np->remote_port);
	udph->len = htons(udp_len);
	udph->check = 0;

	iph = (struct iphdr *)skb_push(skb, sizeof(*iph));

	/* iph->version = 4; iph->ihl = 5; */
	put_unaligned(0x45, (unsigned char *)iph);
	iph->tos      = 0;
	put_unaligned(htons(ip_len), &(iph->tot_len));
	iph->id       = 0;
	iph->frag_off = 0;
	iph->ttl      = 64;
	iph->protocol = IPPROTO_UDP;
	iph->check    = 0;
	put_unaligned(htonl(np->local_ip), &(iph->saddr));
	put_unaligned(htonl(np->remote_ip), &(iph->daddr));
	iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);

	eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);

	eth->h_proto = htons(ETH_P_IP);
	memcpy(eth->h_source, np->local_mac, 6);
	memcpy(eth->h_dest, np->remote_mac, 6);

	skb->dev = np->dev;

	netpoll_send_skb(np, skb);
}

static void arp_reply(struct sk_buff *skb)
{
	struct netpoll_info *npinfo = skb->dev->npinfo;
	struct arphdr *arp;
	unsigned char *arp_ptr;
	int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
	u32 sip, tip;
	unsigned long flags;
	struct sk_buff *send_skb;
	struct netpoll *np = NULL;

	if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
		np = npinfo->rx_np;
	if (!np)
		return;

	/* No arp on this interface */
	if (skb->dev->flags & IFF_NOARP)
		return;

	if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
				 (2 * skb->dev->addr_len) +
				 (2 * sizeof(u32)))))
		return;

	skb->h.raw = skb->nh.raw = skb->data;
	arp = skb->nh.arph;

	if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
	     arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
	    arp->ar_pro != htons(ETH_P_IP) ||
	    arp->ar_op != htons(ARPOP_REQUEST))
		return;

	arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
	memcpy(&sip, arp_ptr, 4);
	arp_ptr += 4 + skb->dev->addr_len;
	memcpy(&tip, arp_ptr, 4);

	/* Should we ignore arp? */
	if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
		return;

	size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
	send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
			    LL_RESERVED_SPACE(np->dev));

	if (!send_skb)
		return;

	send_skb->nh.raw = send_skb->data;
	arp = (struct arphdr *) skb_put(send_skb, size);
	send_skb->dev = skb->dev;
	send_skb->protocol = htons(ETH_P_ARP);

	/* Fill the device header for the ARP frame */

	if (np->dev->hard_header &&
	    np->dev->hard_header(send_skb, skb->dev, ptype,
				       np->remote_mac, np->local_mac,
				       send_skb->len) < 0) {
		kfree_skb(send_skb);
		return;
	}

	/*
	 * Fill out the arp protocol part.
	 *
	 * we only support ethernet device type,
	 * which (according to RFC 1390) should always equal 1 (Ethernet).
	 */

	arp->ar_hrd = htons(np->dev->type);
	arp->ar_pro = htons(ETH_P_IP);
	arp->ar_hln = np->dev->addr_len;
	arp->ar_pln = 4;
	arp->ar_op = htons(type);

	arp_ptr=(unsigned char *)(arp + 1);
	memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
	arp_ptr += np->dev->addr_len;
	memcpy(arp_ptr, &tip, 4);
	arp_ptr += 4;
	memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
	arp_ptr += np->dev->addr_len;
	memcpy(arp_ptr, &sip, 4);

	netpoll_send_skb(np, send_skb);
}

int __netpoll_rx(struct sk_buff *skb)
{
	int proto, len, ulen;
	struct iphdr *iph;
	struct udphdr *uh;
	struct netpoll *np = skb->dev->npinfo->rx_np;

	if (!np)
		goto out;
	if (skb->dev->type != ARPHRD_ETHER)
		goto out;

	/* check if netpoll clients need ARP */
	if (skb->protocol == __constant_htons(ETH_P_ARP) &&
	    atomic_read(&trapped)) {
		arp_reply(skb);
		return 1;
	}

	proto = ntohs(eth_hdr(skb)->h_proto);
	if (proto != ETH_P_IP)
		goto out;
	if (skb->pkt_type == PACKET_OTHERHOST)
		goto out;
	if (skb_shared(skb))
		goto out;

	iph = (struct iphdr *)skb->data;
	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
		goto out;
	if (iph->ihl < 5 || iph->version != 4)
		goto out;
	if (!pskb_may_pull(skb, iph->ihl*4))
		goto out;
	if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
		goto out;

	len = ntohs(iph->tot_len);
	if (skb->len < len || len < iph->ihl*4)
		goto out;

	if (iph->protocol != IPPROTO_UDP)
		goto out;

	len -= iph->ihl*4;
	uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
	ulen = ntohs(uh->len);

	if (ulen != len)
		goto out;
	if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
		goto out;
	if (np->local_ip && np->local_ip != ntohl(iph->daddr))
		goto out;
	if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
		goto out;
	if (np->local_port && np->local_port != ntohs(uh->dest))
		goto out;

	np->rx_hook(np, ntohs(uh->source),
		    (char *)(uh+1),
		    ulen - sizeof(struct udphdr));

	kfree_skb(skb);
	return 1;

out:
	if (atomic_read(&trapped)) {
		kfree_skb(skb);
		return 1;
	}

	return 0;
}

int netpoll_parse_options(struct netpoll *np, char *opt)
{
	char *cur=opt, *delim;

	if(*cur != '@') {
		if ((delim = strchr(cur, '@')) == NULL)
			goto parse_failed;
		*delim=0;
		np->local_port=simple_strtol(cur, NULL, 10);
		cur=delim;
	}
	cur++;
	printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);

	if(*cur != '/') {
		if ((delim = strchr(cur, '/')) == NULL)
			goto parse_failed;
		*delim=0;
		np->local_ip=ntohl(in_aton(cur));
		cur=delim;

		printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
		       np->name, HIPQUAD(np->local_ip));
	}
	cur++;

	if ( *cur != ',') {
		/* parse out dev name */
		if ((delim = strchr(cur, ',')) == NULL)
			goto parse_failed;
		*delim=0;
		strlcpy(np->dev_name, cur, sizeof(np->dev_name));
		cur=delim;
	}
	cur++;

	printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);

	if ( *cur != '@' ) {
		/* dst port */
		if ((delim = strchr(cur, '@')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_port=simple_strtol(cur, NULL, 10);
		cur=delim;
	}
	cur++;
	printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);

	/* dst ip */
	if ((delim = strchr(cur, '/')) == NULL)
		goto parse_failed;
	*delim=0;
	np->remote_ip=ntohl(in_aton(cur));
	cur=delim+1;

	printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
		       np->name, HIPQUAD(np->remote_ip));

	if( *cur != 0 )
	{
		/* MAC address */
		if ((delim = strchr(cur, ':')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_mac[0]=simple_strtol(cur, NULL, 16);
		cur=delim+1;
		if ((delim = strchr(cur, ':')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_mac[1]=simple_strtol(cur, NULL, 16);
		cur=delim+1;
		if ((delim = strchr(cur, ':')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_mac[2]=simple_strtol(cur, NULL, 16);
		cur=delim+1;
		if ((delim = strchr(cur, ':')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_mac[3]=simple_strtol(cur, NULL, 16);
		cur=delim+1;
		if ((delim = strchr(cur, ':')) == NULL)
			goto parse_failed;
		*delim=0;
		np->remote_mac[4]=simple_strtol(cur, NULL, 16);
		cur=delim+1;
		np->remote_mac[5]=simple_strtol(cur, NULL, 16);
	}

	printk(KERN_INFO "%s: remote ethernet address "
	       "%02x:%02x:%02x:%02x:%02x:%02x\n",
	       np->name,
	       np->remote_mac[0],
	       np->remote_mac[1],
	       np->remote_mac[2],
	       np->remote_mac[3],
	       np->remote_mac[4],
	       np->remote_mac[5]);

	return 0;

 parse_failed:
	printk(KERN_INFO "%s: couldn't parse config at %s!\n",
	       np->name, cur);
	return -1;
}

int netpoll_setup(struct netpoll *np)
{
	struct net_device *ndev = NULL;
	struct in_device *in_dev;
	struct netpoll_info *npinfo;
	unsigned long flags;

	if (np->dev_name)
		ndev = dev_get_by_name(np->dev_name);
	if (!ndev) {
		printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
		       np->name, np->dev_name);
		return -1;
	}

	np->dev = ndev;
	if (!ndev->npinfo) {
		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
		if (!npinfo)
			goto release;

		npinfo->rx_flags = 0;
		npinfo->rx_np = NULL;
		npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
		npinfo->poll_owner = -1;
		npinfo->tries = MAX_RETRIES;
		npinfo->rx_lock = SPIN_LOCK_UNLOCKED;
	} else
		npinfo = ndev->npinfo;

	if (!ndev->poll_controller) {
		printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
		       np->name, np->dev_name);
		goto release;
	}

	if (!netif_running(ndev)) {
		unsigned long atmost, atleast;

		printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
		       np->name, np->dev_name);

		rtnl_shlock();
		if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
			printk(KERN_ERR "%s: failed to open %s\n",
			       np->name, np->dev_name);
			rtnl_shunlock();
			goto release;
		}
		rtnl_shunlock();

		atleast = jiffies + HZ/10;
 		atmost = jiffies + 4*HZ;
		while (!netif_carrier_ok(ndev)) {
			if (time_after(jiffies, atmost)) {
				printk(KERN_NOTICE
				       "%s: timeout waiting for carrier\n",
				       np->name);
				break;
			}
			cond_resched();
		}

		/* If carrier appears to come up instantly, we don't
		 * trust it and pause so that we don't pump all our
		 * queued console messages into the bitbucket.
		 */

		if (time_before(jiffies, atleast)) {
			printk(KERN_NOTICE "%s: carrier detect appears"
			       " untrustworthy, waiting 4 seconds\n",
			       np->name);
			msleep(4000);
		}
	}

	if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
		memcpy(np->local_mac, ndev->dev_addr, 6);

	if (!np->local_ip) {
		rcu_read_lock();
		in_dev = __in_dev_get(ndev);

		if (!in_dev || !in_dev->ifa_list) {
			rcu_read_unlock();
			printk(KERN_ERR "%s: no IP address for %s, aborting\n",
			       np->name, np->dev_name);
			goto release;
		}

		np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
		rcu_read_unlock();
		printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
		       np->name, HIPQUAD(np->local_ip));
	}

	if (np->rx_hook) {
		spin_lock_irqsave(&npinfo->rx_lock, flags);
		npinfo->rx_flags |= NETPOLL_RX_ENABLED;
		npinfo->rx_np = np;
		spin_unlock_irqrestore(&npinfo->rx_lock, flags);
	}

	/* fill up the skb queue */
	refill_skbs();

	/* last thing to do is link it to the net device structure */
	ndev->npinfo = npinfo;

	return 0;

 release:
	if (!ndev->npinfo)
		kfree(npinfo);
	np->dev = NULL;
	dev_put(ndev);
	return -1;
}

void netpoll_cleanup(struct netpoll *np)
{
	struct netpoll_info *npinfo;
	unsigned long flags;

	if (np->dev) {
		npinfo = np->dev->npinfo;
		if (npinfo && npinfo->rx_np == np) {
			spin_lock_irqsave(&npinfo->rx_lock, flags);
			npinfo->rx_np = NULL;
			npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
			spin_unlock_irqrestore(&npinfo->rx_lock, flags);
		}
		dev_put(np->dev);
	}

	np->dev = NULL;
}

int netpoll_trap(void)
{
	return atomic_read(&trapped);
}

void netpoll_set_trap(int trap)
{
	if (trap)
		atomic_inc(&trapped);
	else
		atomic_dec(&trapped);
}

EXPORT_SYMBOL(netpoll_set_trap);
EXPORT_SYMBOL(netpoll_trap);
EXPORT_SYMBOL(netpoll_parse_options);
EXPORT_SYMBOL(netpoll_setup);
EXPORT_SYMBOL(netpoll_cleanup);
EXPORT_SYMBOL(netpoll_send_udp);
EXPORT_SYMBOL(netpoll_poll);
EXPORT_SYMBOL(netpoll_queue);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Common framework for low-level network console, dump, and debugger code
	3	*
	4	* Sep 8 2003 Matt Mackall <mpm@selenic.com>
	5	*
	6	* based on the netconsole code from:
	7	*
	8	* Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
	9	* Copyright (C) 2002 Red Hat, Inc.
	10	*/
	11
	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>
	24	#include <net/tcp.h>
	25	#include <net/udp.h>
	26	#include <asm/unaligned.h>
	27
	28	/*
	29	* We maintain a small pool of fully-sized skbs, to make sure the
	30	* message gets out even in extreme OOM situations.
	31	*/
	32
	33	#define MAX_UDP_CHUNK 1460
	34	#define MAX_SKBS 32
	35	#define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
0db1d6fc	36	#define MAX_RETRIES 20000
1da177e4 LT	37
	38	static DEFINE_SPINLOCK(skb_list_lock);
	39	static int nr_skbs;
	40	static struct sk_buff *skbs;
	41
	42	static DEFINE_SPINLOCK(queue_lock);
	43	static int queue_depth;
	44	static struct sk_buff queue_head, queue_tail;
	45
	46	static atomic_t trapped;
	47
	48	#define NETPOLL_RX_ENABLED 1
	49	#define NETPOLL_RX_DROP 2
	50
	51	#define MAX_SKB_SIZE \
	52	(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
	53	sizeof(struct iphdr) + sizeof(struct ethhdr))
	54
	55	static void zap_completion_queue(void);
	56
	57	static void queue_process(void *p)
	58	{
	59	unsigned long flags;
	60	struct sk_buff *skb;
	61
	62	while (queue_head) {
	63	spin_lock_irqsave(&queue_lock, flags);
	64
	65	skb = queue_head;
	66	queue_head = skb->next;
	67	if (skb == queue_tail)
	68	queue_head = NULL;
	69
	70	queue_depth--;
	71
	72	spin_unlock_irqrestore(&queue_lock, flags);
	73
	74	dev_queue_xmit(skb);
	75	}
	76	}
	77
	78	static DECLARE_WORK(send_queue, queue_process, NULL);
	79
	80	void netpoll_queue(struct sk_buff *skb)
	81	{
	82	unsigned long flags;
	83
	84	if (queue_depth == MAX_QUEUE_DEPTH) {
	85	__kfree_skb(skb);
	86	return;
	87	}
	88
	89	spin_lock_irqsave(&queue_lock, flags);
	90	if (!queue_head)
	91	queue_head = skb;
	92	else
	93	queue_tail->next = skb;
	94	queue_tail = skb;
	95	queue_depth++;
	96	spin_unlock_irqrestore(&queue_lock, flags);
	97
	98	schedule_work(&send_queue);
	99	}
	100
101	static int checksum_udp(struct sk_buff skb, struct udphdr uh,
102	unsigned short ulen, u32 saddr, u32 daddr)
103	{
104	if (uh->check == 0)
105	return 0;
106
107	if (skb->ip_summed == CHECKSUM_HW)
108	return csum_tcpudp_magic(
109	saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
110
111	skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
112
113	return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
114	}
115
116	/*
117	* Check whether delayed processing was scheduled for our NIC. If so,
118	* we attempt to grab the poll lock and use ->poll() to pump the card.
119	* If this fails, either we've recursed in ->poll() or it's already
120	* running on another CPU.
121	*
122	* Note: we don't mask interrupts with this lock because we're using
123	* trylock here and interrupts are already disabled in the softirq
124	* case. Further, we test the poll_owner to avoid recursion on UP
125	* systems where the lock doesn't exist.
126	*
127	* In cases where there is bi-directional communications, reading only
128	* one message at a time can lead to packets being dropped by the
129	* network adapter, forcing superfluous retries and possibly timeouts.
130	* Thus, we set our budget to greater than 1.
131	*/
132	static void poll_napi(struct netpoll *np)
133	{
115c1d6e	134	struct netpoll_info *npinfo = np->dev->npinfo;
1da177e4 LT	135	int budget = 16;
	136
	137	if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
115c1d6e JM	138	npinfo->poll_owner != smp_processor_id() &&
	139	spin_trylock(&npinfo->poll_lock)) {
	140	npinfo->rx_flags \|= NETPOLL_RX_DROP;
1da177e4 LT	141	atomic_inc(&trapped);
	142
	143	np->dev->poll(np->dev, &budget);
	144
	145	atomic_dec(&trapped);
115c1d6e JM	146	npinfo->rx_flags &= ~NETPOLL_RX_DROP;
115c1d6e JM	147	spin_unlock(&npinfo->poll_lock);
1da177e4 LT	148	}
	149	}
	150
	151	void netpoll_poll(struct netpoll *np)
	152	{
	153	if(!np->dev \|\| !netif_running(np->dev) \|\| !np->dev->poll_controller)
	154	return;
	155
	156	/* Process pending work on NIC */
	157	np->dev->poll_controller(np->dev);
	158	if (np->dev->poll)
	159	poll_napi(np);
	160
	161	zap_completion_queue();
	162	}
	163
	164	static void refill_skbs(void)
	165	{
	166	struct sk_buff *skb;
	167	unsigned long flags;
	168
	169	spin_lock_irqsave(&skb_list_lock, flags);
	170	while (nr_skbs < MAX_SKBS) {
	171	skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
	172	if (!skb)
	173	break;
	174
	175	skb->next = skbs;
	176	skbs = skb;
	177	nr_skbs++;
	178	}
	179	spin_unlock_irqrestore(&skb_list_lock, flags);
	180	}
	181
	182	static void zap_completion_queue(void)
	183	{
	184	unsigned long flags;
	185	struct softnet_data *sd = &get_cpu_var(softnet_data);
	186
	187	if (sd->completion_queue) {
	188	struct sk_buff *clist;
	189
	190	local_irq_save(flags);
	191	clist = sd->completion_queue;
	192	sd->completion_queue = NULL;
	193	local_irq_restore(flags);
	194
	195	while (clist != NULL) {
	196	struct sk_buff *skb = clist;
	197	clist = clist->next;
	198	if(skb->destructor)
	199	dev_kfree_skb_any(skb); /* put this one back */
	200	else
	201	__kfree_skb(skb);
	202	}
	203	}
	204
	205	put_cpu_var(softnet_data);
	206	}
	207
	208	static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
	209	{
	210	int once = 1, count = 0;
	211	unsigned long flags;
212	struct sk_buff *skb = NULL;
213
214	zap_completion_queue();
215	repeat:
216	if (nr_skbs < MAX_SKBS)
217	refill_skbs();
218
219	skb = alloc_skb(len, GFP_ATOMIC);
220
221	if (!skb) {
222	spin_lock_irqsave(&skb_list_lock, flags);
223	skb = skbs;
224	if (skb) {
225	skbs = skb->next;
226	skb->next = NULL;
227	nr_skbs--;
228	}
229	spin_unlock_irqrestore(&skb_list_lock, flags);
230	}
231
232	if(!skb) {
233	count++;
234	if (once && (count == 1000000)) {
235	printk("out of netpoll skbs!\n");
236	once = 0;
237	}
238	netpoll_poll(np);
239	goto repeat;
240	}
241
242	atomic_set(&skb->users, 1);
243	skb_reserve(skb, reserve);
244	return skb;
245	}
246
247	static void netpoll_send_skb(struct netpoll np, struct sk_buff skb)
248	{
249	int status;
115c1d6e	250	struct netpoll_info *npinfo;
1da177e4	251
f0d3459d	252	if (!np \|\| !np->dev \|\| !netif_running(np->dev)) {
1da177e4 LT	253	__kfree_skb(skb);
	254	return;
	255	}
	256
115c1d6e	257	npinfo = np->dev->npinfo;
f0d3459d MM	258
f0d3459d MM	259	/* avoid recursion */
115c1d6e JM	260	if (npinfo->poll_owner == smp_processor_id() \|\|
115c1d6e JM	261	np->dev->xmit_lock_owner == smp_processor_id()) {
1da177e4 LT	262	if (np->drop)
	263	np->drop(skb);
	264	else
	265	__kfree_skb(skb);
	266	return;
	267	}
	268
0db1d6fc MM	269	do {
0db1d6fc MM	270	npinfo->tries--;
f0d3459d MM	271	spin_lock(&np->dev->xmit_lock);
	272	np->dev->xmit_lock_owner = smp_processor_id();
	273
	274	/*
	275	* network drivers do not expect to be called if the queue is
	276	* stopped.
	277	*/
	278	if (netif_queue_stopped(np->dev)) {
	279	np->dev->xmit_lock_owner = -1;
	280	spin_unlock(&np->dev->xmit_lock);
	281	netpoll_poll(np);
0db1d6fc	282	udelay(50);
f0d3459d MM	283	continue;
f0d3459d MM	284	}
1da177e4	285
f0d3459d	286	status = np->dev->hard_start_xmit(skb, np->dev);
1da177e4 LT	287	np->dev->xmit_lock_owner = -1;
	288	spin_unlock(&np->dev->xmit_lock);
	289
f0d3459d	290	/* success */
0db1d6fc MM	291	if(!status) {
0db1d6fc MM	292	npinfo->tries = MAX_RETRIES; /* reset */
f0d3459d	293	return;
0db1d6fc	294	}
1da177e4	295
f0d3459d	296	/* transmit busy */
1da177e4	297	netpoll_poll(np);
0db1d6fc MM	298	udelay(50);
0db1d6fc MM	299	} while (npinfo->tries > 0);
1da177e4 LT	300	}
	301
	302	void netpoll_send_udp(struct netpoll np, const char msg, int len)
	303	{
	304	int total_len, eth_len, ip_len, udp_len;
	305	struct sk_buff *skb;
	306	struct udphdr *udph;
	307	struct iphdr *iph;
	308	struct ethhdr *eth;
	309
	310	udp_len = len + sizeof(*udph);
	311	ip_len = eth_len = udp_len + sizeof(*iph);
	312	total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
	313
	314	skb = find_skb(np, total_len, total_len - len);
	315	if (!skb)
	316	return;
	317
	318	memcpy(skb->data, msg, len);
	319	skb->len += len;
	320
	321	udph = (struct udphdr ) skb_push(skb, sizeof(udph));
	322	udph->source = htons(np->local_port);
	323	udph->dest = htons(np->remote_port);
	324	udph->len = htons(udp_len);
	325	udph->check = 0;
	326
	327	iph = (struct iphdr )skb_push(skb, sizeof(iph));
	328
	329	/* iph->version = 4; iph->ihl = 5; */
	330	put_unaligned(0x45, (unsigned char *)iph);
	331	iph->tos = 0;
	332	put_unaligned(htons(ip_len), &(iph->tot_len));
	333	iph->id = 0;
	334	iph->frag_off = 0;
	335	iph->ttl = 64;
	336	iph->protocol = IPPROTO_UDP;
	337	iph->check = 0;
	338	put_unaligned(htonl(np->local_ip), &(iph->saddr));
	339	put_unaligned(htonl(np->remote_ip), &(iph->daddr));
	340	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
	341
	342	eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
	343
	344	eth->h_proto = htons(ETH_P_IP);
	345	memcpy(eth->h_source, np->local_mac, 6);
	346	memcpy(eth->h_dest, np->remote_mac, 6);
	347
	348	skb->dev = np->dev;
	349
	350	netpoll_send_skb(np, skb);
	351	}
	352
	353	static void arp_reply(struct sk_buff *skb)
	354	{
115c1d6e	355	struct netpoll_info *npinfo = skb->dev->npinfo;
1da177e4 LT	356	struct arphdr *arp;
	357	unsigned char *arp_ptr;
	358	int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
	359	u32 sip, tip;
fbeec2e1	360	unsigned long flags;
1da177e4	361	struct sk_buff *send_skb;
115c1d6e	362	struct netpoll *np = NULL;
1da177e4	363
fbeec2e1 JM	364	if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
fbeec2e1 JM	365	np = npinfo->rx_np;
115c1d6e JM	366	if (!np)
115c1d6e JM	367	return;
1da177e4 LT	368
	369	/* No arp on this interface */
	370	if (skb->dev->flags & IFF_NOARP)
	371	return;
	372
	373	if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
	374	(2 * skb->dev->addr_len) +
	375	(2 * sizeof(u32)))))
	376	return;
	377
	378	skb->h.raw = skb->nh.raw = skb->data;
	379	arp = skb->nh.arph;
	380
	381	if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
	382	arp->ar_hrd != htons(ARPHRD_IEEE802)) \|\|
	383	arp->ar_pro != htons(ETH_P_IP) \|\|
	384	arp->ar_op != htons(ARPOP_REQUEST))
	385	return;
	386
	387	arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
	388	memcpy(&sip, arp_ptr, 4);
	389	arp_ptr += 4 + skb->dev->addr_len;
	390	memcpy(&tip, arp_ptr, 4);
	391
	392	/* Should we ignore arp? */
	393	if (tip != htonl(np->local_ip) \|\| LOOPBACK(tip) \|\| MULTICAST(tip))
	394	return;
	395
	396	size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
	397	send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
	398	LL_RESERVED_SPACE(np->dev));
	399
	400	if (!send_skb)
	401	return;
	402
	403	send_skb->nh.raw = send_skb->data;
	404	arp = (struct arphdr *) skb_put(send_skb, size);
	405	send_skb->dev = skb->dev;
	406	send_skb->protocol = htons(ETH_P_ARP);
	407
	408	/* Fill the device header for the ARP frame */
	409
	410	if (np->dev->hard_header &&
	411	np->dev->hard_header(send_skb, skb->dev, ptype,
	412	np->remote_mac, np->local_mac,
	413	send_skb->len) < 0) {
	414	kfree_skb(send_skb);
	415	return;
	416	}
	417
	418	/*
	419	* Fill out the arp protocol part.
	420	*
	421	* we only support ethernet device type,
	422	* which (according to RFC 1390) should always equal 1 (Ethernet).
	423	*/
	424
	425	arp->ar_hrd = htons(np->dev->type);
	426	arp->ar_pro = htons(ETH_P_IP);
	427	arp->ar_hln = np->dev->addr_len;
	428	arp->ar_pln = 4;
	429	arp->ar_op = htons(type);
	430
	431	arp_ptr=(unsigned char *)(arp + 1);
432	memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
433	arp_ptr += np->dev->addr_len;
434	memcpy(arp_ptr, &tip, 4);
435	arp_ptr += 4;
436	memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
437	arp_ptr += np->dev->addr_len;
438	memcpy(arp_ptr, &sip, 4);
439
440	netpoll_send_skb(np, send_skb);
441	}
442
443	int __netpoll_rx(struct sk_buff *skb)
444	{
445	int proto, len, ulen;
446	struct iphdr *iph;
447	struct udphdr *uh;
fbeec2e1	448	struct netpoll *np = skb->dev->npinfo->rx_np;
1da177e4	449
fbeec2e1	450	if (!np)
1da177e4 LT	451	goto out;
	452	if (skb->dev->type != ARPHRD_ETHER)
	453	goto out;
	454
	455	/* check if netpoll clients need ARP */
	456	if (skb->protocol == __constant_htons(ETH_P_ARP) &&
	457	atomic_read(&trapped)) {
	458	arp_reply(skb);
	459	return 1;
	460	}
	461
	462	proto = ntohs(eth_hdr(skb)->h_proto);
	463	if (proto != ETH_P_IP)
	464	goto out;
	465	if (skb->pkt_type == PACKET_OTHERHOST)
	466	goto out;
	467	if (skb_shared(skb))
	468	goto out;
	469
	470	iph = (struct iphdr *)skb->data;
	471	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	472	goto out;
	473	if (iph->ihl < 5 \|\| iph->version != 4)
	474	goto out;
	475	if (!pskb_may_pull(skb, iph->ihl*4))
	476	goto out;
	477	if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
	478	goto out;
	479
	480	len = ntohs(iph->tot_len);
	481	if (skb->len < len \|\| len < iph->ihl*4)
	482	goto out;
	483
	484	if (iph->protocol != IPPROTO_UDP)
	485	goto out;
	486
	487	len -= iph->ihl*4;
	488	uh = (struct udphdr )(((char )iph) + iph->ihl*4);
	489	ulen = ntohs(uh->len);
	490
	491	if (ulen != len)
	492	goto out;
	493	if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
	494	goto out;
	495	if (np->local_ip && np->local_ip != ntohl(iph->daddr))
	496	goto out;
	497	if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
	498	goto out;
	499	if (np->local_port && np->local_port != ntohs(uh->dest))
	500	goto out;
	501
	502	np->rx_hook(np, ntohs(uh->source),
	503	(char *)(uh+1),
	504	ulen - sizeof(struct udphdr));
	505
	506	kfree_skb(skb);
	507	return 1;
	508
	509	out:
	510	if (atomic_read(&trapped)) {
	511	kfree_skb(skb);
	512	return 1;
	513	}
	514
515	return 0;
516	}
517
518	int netpoll_parse_options(struct netpoll np, char opt)
519	{
520	char cur=opt, delim;
521
522	if(*cur != '@') {
523	if ((delim = strchr(cur, '@')) == NULL)
524	goto parse_failed;
525	*delim=0;
526	np->local_port=simple_strtol(cur, NULL, 10);
527	cur=delim;
528	}
529	cur++;
530	printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
531
532	if(*cur != '/') {
533	if ((delim = strchr(cur, '/')) == NULL)
534	goto parse_failed;
535	*delim=0;
536	np->local_ip=ntohl(in_aton(cur));
537	cur=delim;
538
539	printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
540	np->name, HIPQUAD(np->local_ip));
541	}
542	cur++;
543
544	if ( *cur != ',') {
545	/* parse out dev name */
546	if ((delim = strchr(cur, ',')) == NULL)
547	goto parse_failed;
548	*delim=0;
549	strlcpy(np->dev_name, cur, sizeof(np->dev_name));
550	cur=delim;
551	}
552	cur++;
553
554	printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
555
556	if ( *cur != '@' ) {
557	/* dst port */
558	if ((delim = strchr(cur, '@')) == NULL)
559	goto parse_failed;
560	*delim=0;
561	np->remote_port=simple_strtol(cur, NULL, 10);
562	cur=delim;
563	}
564	cur++;
565	printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
566
567	/* dst ip */
568	if ((delim = strchr(cur, '/')) == NULL)
569	goto parse_failed;
570	*delim=0;
571	np->remote_ip=ntohl(in_aton(cur));
572	cur=delim+1;
573
574	printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
575	np->name, HIPQUAD(np->remote_ip));
576
577	if( *cur != 0 )
578	{
579	/* MAC address */
580	if ((delim = strchr(cur, ':')) == NULL)
581	goto parse_failed;
582	*delim=0;
583	np->remote_mac[0]=simple_strtol(cur, NULL, 16);
584	cur=delim+1;
585	if ((delim = strchr(cur, ':')) == NULL)
586	goto parse_failed;
587	*delim=0;
588	np->remote_mac[1]=simple_strtol(cur, NULL, 16);
589	cur=delim+1;
590	if ((delim = strchr(cur, ':')) == NULL)
591	goto parse_failed;
592	*delim=0;
593	np->remote_mac[2]=simple_strtol(cur, NULL, 16);
594	cur=delim+1;
595	if ((delim = strchr(cur, ':')) == NULL)
596	goto parse_failed;
597	*delim=0;
598	np->remote_mac[3]=simple_strtol(cur, NULL, 16);
599	cur=delim+1;
600	if ((delim = strchr(cur, ':')) == NULL)
601	goto parse_failed;
602	*delim=0;
603	np->remote_mac[4]=simple_strtol(cur, NULL, 16);
604	cur=delim+1;
605	np->remote_mac[5]=simple_strtol(cur, NULL, 16);
606	}
607
608	printk(KERN_INFO "%s: remote ethernet address "
609	"%02x:%02x:%02x:%02x:%02x:%02x\n",
610	np->name,
611	np->remote_mac[0],
612	np->remote_mac[1],
613	np->remote_mac[2],
614	np->remote_mac[3],
615	np->remote_mac[4],
616	np->remote_mac[5]);
617
618	return 0;
619
620	parse_failed:
621	printk(KERN_INFO "%s: couldn't parse config at %s!\n",
622	np->name, cur);
623	return -1;
624	}
625
626	int netpoll_setup(struct netpoll *np)
627	{
628	struct net_device *ndev = NULL;
629	struct in_device *in_dev;
115c1d6e	630	struct netpoll_info *npinfo;
fbeec2e1	631	unsigned long flags;
1da177e4 LT	632
	633	if (np->dev_name)
	634	ndev = dev_get_by_name(np->dev_name);
	635	if (!ndev) {
	636	printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
	637	np->name, np->dev_name);
	638	return -1;
	639	}
	640
	641	np->dev = ndev;
115c1d6e JM	642	if (!ndev->npinfo) {
	643	npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
	644	if (!npinfo)
	645	goto release;
	646
11513128	647	npinfo->rx_flags = 0;
fbeec2e1	648	npinfo->rx_np = NULL;
115c1d6e JM	649	npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
115c1d6e JM	650	npinfo->poll_owner = -1;
0db1d6fc	651	npinfo->tries = MAX_RETRIES;
fbeec2e1	652	npinfo->rx_lock = SPIN_LOCK_UNLOCKED;
115c1d6e JM	653	} else
115c1d6e JM	654	npinfo = ndev->npinfo;
1da177e4 LT	655
	656	if (!ndev->poll_controller) {
	657	printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
	658	np->name, np->dev_name);
	659	goto release;
	660	}
	661
	662	if (!netif_running(ndev)) {
	663	unsigned long atmost, atleast;
	664
	665	printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
	666	np->name, np->dev_name);
	667
	668	rtnl_shlock();
	669	if (dev_change_flags(ndev, ndev->flags \| IFF_UP) < 0) {
	670	printk(KERN_ERR "%s: failed to open %s\n",
	671	np->name, np->dev_name);
	672	rtnl_shunlock();
	673	goto release;
	674	}
	675	rtnl_shunlock();
	676
	677	atleast = jiffies + HZ/10;
	678	atmost = jiffies + 4*HZ;
	679	while (!netif_carrier_ok(ndev)) {
	680	if (time_after(jiffies, atmost)) {
	681	printk(KERN_NOTICE
	682	"%s: timeout waiting for carrier\n",
	683	np->name);
	684	break;
	685	}
	686	cond_resched();
	687	}
	688
	689	/* If carrier appears to come up instantly, we don't
	690	* trust it and pause so that we don't pump all our
	691	* queued console messages into the bitbucket.
	692	*/
	693
	694	if (time_before(jiffies, atleast)) {
	695	printk(KERN_NOTICE "%s: carrier detect appears"
	696	" untrustworthy, waiting 4 seconds\n",
	697	np->name);
	698	msleep(4000);
	699	}
	700	}
	701
	702	if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
	703	memcpy(np->local_mac, ndev->dev_addr, 6);
	704
	705	if (!np->local_ip) {
	706	rcu_read_lock();
	707	in_dev = __in_dev_get(ndev);
	708
	709	if (!in_dev \|\| !in_dev->ifa_list) {
	710	rcu_read_unlock();
	711	printk(KERN_ERR "%s: no IP address for %s, aborting\n",
	712	np->name, np->dev_name);
	713	goto release;
	714	}
	715
	716	np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
	717	rcu_read_unlock();
	718	printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
719	np->name, HIPQUAD(np->local_ip));
720	}
721
fbeec2e1 JM	722	if (np->rx_hook) {
	723	spin_lock_irqsave(&npinfo->rx_lock, flags);
	724	npinfo->rx_flags \|= NETPOLL_RX_ENABLED;
	725	npinfo->rx_np = np;
	726	spin_unlock_irqrestore(&npinfo->rx_lock, flags);
	727	}
26520765 IM	728
	729	/* fill up the skb queue */
	730	refill_skbs();
	731
fbeec2e1	732	/* last thing to do is link it to the net device structure */
115c1d6e	733	ndev->npinfo = npinfo;
1da177e4 LT	734
	735	return 0;
	736
	737	release:
115c1d6e JM	738	if (!ndev->npinfo)
115c1d6e JM	739	kfree(npinfo);
1da177e4 LT	740	np->dev = NULL;
	741	dev_put(ndev);
	742	return -1;
	743	}
	744
	745	void netpoll_cleanup(struct netpoll *np)
	746	{
fbeec2e1 JM	747	struct netpoll_info *npinfo;
	748	unsigned long flags;
	749
115c1d6e	750	if (np->dev) {
fbeec2e1 JM	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);
	757	}
115c1d6e JM	758	dev_put(np->dev);
115c1d6e JM	759	}
fbeec2e1	760
1da177e4 LT	761	np->dev = NULL;
	762	}
	763
	764	int netpoll_trap(void)
	765	{
	766	return atomic_read(&trapped);
	767	}
	768
	769	void netpoll_set_trap(int trap)
	770	{
	771	if (trap)
	772	atomic_inc(&trapped);
	773	else
	774	atomic_dec(&trapped);
	775	}
	776
	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);