clip.c

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/* net/atm/clip.c - RFC1577 Classical IP over ATM */

/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */


#include <linux/config.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/kernel.h> /* for UINT_MAX */
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/timer.h>
#include <linux/if_arp.h> /* for some manifest constants */
#include <linux/notifier.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/atmclip.h>
#include <linux/atmarp.h>
#include <linux/ip.h> /* for net/route.h */
#include <linux/in.h> /* for struct sockaddr_in */
#include <linux/if.h> /* for IFF_UP */
#include <linux/inetdevice.h>
#include <linux/bitops.h>
#include <net/route.h> /* for struct rtable and routing */
#include <net/icmp.h> /* icmp_send */
#include <asm/param.h> /* for HZ */
#include <asm/byteorder.h> /* for htons etc. */
#include <asm/system.h> /* save/restore_flags */
#include <asm/uaccess.h>
#include <asm/atomic.h>

#include "common.h"
#include "resources.h"
#include "ipcommon.h"
#include <net/atmclip.h>


#if 0
#define DPRINTK(format,args...) printk(format,##args)
#else
#define DPRINTK(format,args...)
#endif


struct net_device *clip_devs = NULL;
struct atm_vcc *atmarpd = NULL;
static struct timer_list idle_timer;
static int start_timer = 1;


static int to_atmarpd(enum atmarp_ctrl_type type,int itf,unsigned long ip)
{
	struct atmarp_ctrl *ctrl;
	struct sk_buff *skb;

	DPRINTK("to_atmarpd(%d)\n",type);
	if (!atmarpd) return -EUNATCH;
	skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
	if (!skb) return -ENOMEM;
	ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
	ctrl->type = type;
	ctrl->itf_num = itf;
	ctrl->ip = ip;
	atm_force_charge(atmarpd,skb->truesize);
	skb_queue_tail(&atmarpd->recvq,skb);
	wake_up(&atmarpd->sleep);
	return 0;
}


static void link_vcc(struct clip_vcc *clip_vcc,struct atmarp_entry *entry)
{
	DPRINTK("link_vcc %p to entry %p (neigh %p)\n",clip_vcc,entry,
	    entry->neigh);
	clip_vcc->entry = entry;
	clip_vcc->xoff = 0; /* @@@ may overrun buffer by one packet */
	clip_vcc->next = entry->vccs;
	entry->vccs = clip_vcc;
	entry->neigh->used = jiffies;
}


static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
{
	struct atmarp_entry *entry = clip_vcc->entry;
	struct clip_vcc **walk;

	if (!entry) {
		printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n",clip_vcc);
		return;
	}
	entry->neigh->used = jiffies;
	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
		if (*walk == clip_vcc) {
			int error;

			*walk = clip_vcc->next; /* atomic */
			clip_vcc->entry = NULL;
			if (clip_vcc->xoff)
				netif_wake_queue(entry->neigh->dev);
			if (entry->vccs) return;
			entry->expires = jiffies-1;
				/* force resolution or expiration */
			error = neigh_update(entry->neigh,NULL,NUD_NONE,0,0);
			if (error)
				printk(KERN_CRIT "unlink_clip_vcc: "
				    "neigh_update failed with %d\n",error);
			return;
		}
	printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
	  "0x%p)\n",entry,clip_vcc);
}


static void idle_timer_check(unsigned long dummy)
{
	int i;

	/*DPRINTK("idle_timer_check\n");*/
	write_lock(&clip_tbl.lock);
	for (i = 0; i <= NEIGH_HASHMASK; i++) {
		struct neighbour **np;

		for (np = &clip_tbl.hash_buckets[i]; *np;) {
			struct neighbour *n = *np;
			struct atmarp_entry *entry = NEIGH2ENTRY(n);
			struct clip_vcc *clip_vcc;

			for (clip_vcc = entry->vccs; clip_vcc;
			    clip_vcc = clip_vcc->next)
				if (clip_vcc->idle_timeout &&
				    time_after(jiffies, clip_vcc->last_use+
				    clip_vcc->idle_timeout)) {
					DPRINTK("releasing vcc %p->%p of "
					    "entry %p\n",clip_vcc,clip_vcc->vcc,
					    entry);
					atm_async_release_vcc(clip_vcc->vcc,
					    -ETIMEDOUT);
				}
			if (entry->vccs ||
			    time_before(jiffies, entry->expires)) {
				np = &n->next;
				continue;
			}
			if (atomic_read(&n->refcnt) > 1) {
				struct sk_buff *skb;

				DPRINTK("destruction postponed with ref %d\n",
				    atomic_read(&n->refcnt));
				while ((skb = skb_dequeue(&n->arp_queue)) !=
				     NULL) 
					dev_kfree_skb(skb);
				np = &n->next;
				continue;
			}
			*np = n->next;
			DPRINTK("expired neigh %p\n",n);
			n->dead = 1;
			neigh_release(n);
		}
	}
	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
	write_unlock(&clip_tbl.lock);
}


static int clip_arp_rcv(struct sk_buff *skb)
{
	struct atm_vcc *vcc;

	DPRINTK("clip_arp_rcv\n");
	vcc = ATM_SKB(skb)->vcc;
	if (!vcc || !atm_charge(vcc,skb->truesize)) {
		dev_kfree_skb_any(skb);
		return 0;
	}
	DPRINTK("pushing to %p\n",vcc);
	DPRINTK("using %p\n",CLIP_VCC(vcc)->old_push);
	CLIP_VCC(vcc)->old_push(vcc,skb);
	return 0;
}


void clip_push(struct atm_vcc *vcc,struct sk_buff *skb)
{
	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);

	DPRINTK("clip push\n");
	if (!skb) {
		DPRINTK("removing VCC %p\n",clip_vcc);
		if (clip_vcc->entry) unlink_clip_vcc(clip_vcc);
		clip_vcc->old_push(vcc,NULL); /* pass on the bad news */
		kfree(clip_vcc);
		return;
	}
	atm_return(vcc,skb->truesize);
	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
		/* clip_vcc->entry == NULL if we don't have an IP address yet */
	if (!skb->dev) {
		dev_kfree_skb_any(skb);
		return;
	}
	ATM_SKB(skb)->vcc = vcc;
	skb->mac.raw = skb->data;
	if (!clip_vcc->encap || skb->len < RFC1483LLC_LEN || memcmp(skb->data,
	    llc_oui,sizeof(llc_oui))) skb->protocol = htons(ETH_P_IP);
	else {
		skb->protocol = ((u16 *) skb->data)[3];
		skb_pull(skb,RFC1483LLC_LEN);
		if (skb->protocol == htons(ETH_P_ARP)) {
			PRIV(skb->dev)->stats.rx_packets++;
			PRIV(skb->dev)->stats.rx_bytes += skb->len;
			clip_arp_rcv(skb);
			return;
		}
	}
	clip_vcc->last_use = jiffies;
	PRIV(skb->dev)->stats.rx_packets++;
	PRIV(skb->dev)->stats.rx_bytes += skb->len;
	netif_rx(skb);
}


/*
 * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
 * clip_pop is atomic with respect to the critical section in clip_start_xmit.
 */


static void clip_pop(struct atm_vcc *vcc,struct sk_buff *skb)
{
	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
	struct net_device *dev = skb->dev;
	int old;
	unsigned long flags;

	DPRINTK("clip_pop(vcc %p)\n",vcc);
	clip_vcc->old_pop(vcc,skb);
	/* skb->dev == NULL in outbound ARP packets */
	if (!dev) return;
	spin_lock_irqsave(&PRIV(dev)->xoff_lock,flags);
	if (atm_may_send(vcc,0)) {
		old = xchg(&clip_vcc->xoff,0);
		if (old) netif_wake_queue(dev);
	}
	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock,flags);
}


static void clip_neigh_destroy(struct neighbour *neigh)
{
	DPRINTK("clip_neigh_destroy (neigh %p)\n",neigh);
	if (NEIGH2ENTRY(neigh)->vccs)
		printk(KERN_CRIT "clip_neigh_destroy: vccs != NULL !!!\n");
	NEIGH2ENTRY(neigh)->vccs = (void *) 0xdeadbeef;
}


static void clip_neigh_solicit(struct neighbour *neigh,struct sk_buff *skb)
{
	DPRINTK("clip_neigh_solicit (neigh %p, skb %p)\n",neigh,skb);
	to_atmarpd(act_need,PRIV(neigh->dev)->number,NEIGH2ENTRY(neigh)->ip);
}


static void clip_neigh_error(struct neighbour *neigh,struct sk_buff *skb)
{
#ifndef CONFIG_ATM_CLIP_NO_ICMP
	icmp_send(skb,ICMP_DEST_UNREACH,ICMP_HOST_UNREACH,0);
#endif
	kfree_skb(skb);
}


static struct neigh_ops clip_neigh_ops = {
	family:			AF_INET,
	destructor:		clip_neigh_destroy,
	solicit:		clip_neigh_solicit,
	error_report:		clip_neigh_error,
	output:			dev_queue_xmit,
	connected_output:	dev_queue_xmit,
	hh_output:		dev_queue_xmit,
	queue_xmit:		dev_queue_xmit,
};


static int clip_constructor(struct neighbour *neigh)
{
	struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
	struct net_device *dev = neigh->dev;
	struct in_device *in_dev = dev->ip_ptr;

	DPRINTK("clip_constructor (neigh %p, entry %p)\n",neigh,entry);
	if (!in_dev) return -EINVAL;
	neigh->type = inet_addr_type(entry->ip);
	if (neigh->type != RTN_UNICAST) return -EINVAL;
	if (in_dev->arp_parms) neigh->parms = in_dev->arp_parms;
	neigh->ops = &clip_neigh_ops;
	neigh->output = neigh->nud_state & NUD_VALID ?
	    neigh->ops->connected_output : neigh->ops->output;
	entry->neigh = neigh;
	entry->vccs = NULL;
	entry->expires = jiffies-1;
	return 0;
}

static u32 clip_hash(const void *pkey, const struct net_device *dev)
{
	u32 hash_val;

	hash_val = *(u32*)pkey;
	hash_val ^= (hash_val>>16);
	hash_val ^= hash_val>>8;
	hash_val ^= hash_val>>3;
	hash_val = (hash_val^dev->ifindex)&NEIGH_HASHMASK;

	return hash_val;
}


struct neigh_table clip_tbl = {
	NULL,			/* next */
	AF_INET,		/* family */
	sizeof(struct neighbour)+sizeof(struct atmarp_entry), /* entry_size */
	4,			/* key_len */
	clip_hash,
	clip_constructor,	/* constructor */
	NULL,			/* pconstructor */
	NULL,			/* pdestructor */
	NULL,			/* proxy_redo */
	"clip_arp_cache",
	{			/* neigh_parms */
		NULL,		/* next */
		NULL,		/* neigh_setup */
		&clip_tbl,	/* tbl */
		0,		/* entries */
		NULL,		/* priv */
		NULL,		/* sysctl_table */
		30*HZ,		/* base_reachable_time */
		1*HZ,		/* retrans_time */
		60*HZ,		/* gc_staletime */
		30*HZ,		/* reachable_time */
		5*HZ,		/* delay_probe_time */
		3,		/* queue_len */
		3,		/* ucast_probes */
		0,		/* app_probes */
		3,		/* mcast_probes */
		1*HZ,		/* anycast_delay */
		(8*HZ)/10,	/* proxy_delay */
		1*HZ,		/* proxy_qlen */
		64		/* locktime */
	},
	30*HZ,128,512,1024	/* copied from ARP ... */
};


/* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */

/*
 * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
 * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
 * don't increment the usage count. This is used to create entries in
 * clip_setentry.
 */


int clip_encap(struct atm_vcc *vcc,int mode)
{
	CLIP_VCC(vcc)->encap = mode;
	return 0;
}


static int clip_start_xmit(struct sk_buff *skb,struct net_device *dev)
{
	struct clip_priv *clip_priv = PRIV(dev);
	struct atmarp_entry *entry;