arp.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

	kfree_skb(skb);
out_of_mem:
	return 0;
}



/*
 *	User level interface (ioctl, /proc)
 */

/*
 *	Set (create) an ARP cache entry.
 */

int arp_req_set(struct arpreq *r, struct net_device * dev)
{
	u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
	struct neighbour *neigh;
	int err;

	if (r->arp_flags&ATF_PUBL) {
		u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
		if (mask && mask != 0xFFFFFFFF)
			return -EINVAL;
		if (!dev && (r->arp_flags & ATF_COM)) {
			dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data);
			if (!dev)
				return -ENODEV;
		}
		if (mask) {
			if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL)
				return -ENOBUFS;
			return 0;
		}
		if (dev == NULL) {
			ipv4_devconf.proxy_arp = 1;
			return 0;
		}
		if (__in_dev_get(dev)) {
			__in_dev_get(dev)->cnf.proxy_arp = 1;
			return 0;
		}
		return -ENXIO;
	}

	if (r->arp_flags & ATF_PERM)
		r->arp_flags |= ATF_COM;
	if (dev == NULL) {
		struct rtable * rt;
		if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
			return err;
		dev = rt->u.dst.dev;
		ip_rt_put(rt);
		if (!dev)
			return -EINVAL;
	}
	if (r->arp_ha.sa_family != dev->type)	
		return -EINVAL;

	neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
	err = PTR_ERR(neigh);
	if (!IS_ERR(neigh)) {
		unsigned state = NUD_STALE;
		if (r->arp_flags & ATF_PERM)
			state = NUD_PERMANENT;
		err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
				   r->arp_ha.sa_data : NULL, state, 1, 0);
		neigh_release(neigh);
	}
	return err;
}

static unsigned arp_state_to_flags(struct neighbour *neigh)
{
	unsigned flags = 0;
	if (neigh->nud_state&NUD_PERMANENT)
		flags = ATF_PERM|ATF_COM;
	else if (neigh->nud_state&NUD_VALID)
		flags = ATF_COM;
	return flags;
}

/*
 *	Get an ARP cache entry.
 */

static int arp_req_get(struct arpreq *r, struct net_device *dev)
{
	u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
	struct neighbour *neigh;
	int err = -ENXIO;

	neigh = neigh_lookup(&arp_tbl, &ip, dev);
	if (neigh) {
		read_lock_bh(&neigh->lock);
		memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
		r->arp_flags = arp_state_to_flags(neigh);
		read_unlock_bh(&neigh->lock);
		r->arp_ha.sa_family = dev->type;
		strncpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
		neigh_release(neigh);
		err = 0;
	}
	return err;
}

int arp_req_delete(struct arpreq *r, struct net_device * dev)
{
	int err;
	u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
	struct neighbour *neigh;

	if (r->arp_flags & ATF_PUBL) {
		u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
		if (mask == 0xFFFFFFFF)
			return pneigh_delete(&arp_tbl, &ip, dev);
		if (mask == 0) {
			if (dev == NULL) {
				ipv4_devconf.proxy_arp = 0;
				return 0;
			}
			if (__in_dev_get(dev)) {
				__in_dev_get(dev)->cnf.proxy_arp = 0;
				return 0;
			}
			return -ENXIO;
		}
		return -EINVAL;
	}

	if (dev == NULL) {
		struct rtable * rt;
		if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
			return err;
		dev = rt->u.dst.dev;
		ip_rt_put(rt);
		if (!dev)
			return -EINVAL;
	}
	err = -ENXIO;
	neigh = neigh_lookup(&arp_tbl, &ip, dev);
	if (neigh) {
		if (neigh->nud_state&~NUD_NOARP)
			err = neigh_update(neigh, NULL, NUD_FAILED, 1, 0);
		neigh_release(neigh);
	}
	return err;
}

/*
 *	Handle an ARP layer I/O control request.
 */

int arp_ioctl(unsigned int cmd, void *arg)
{
	int err;
	struct arpreq r;
	struct net_device * dev = NULL;

	switch(cmd) {
		case SIOCDARP:
		case SIOCSARP:
			if (!capable(CAP_NET_ADMIN))
				return -EPERM;
		case SIOCGARP:
			err = copy_from_user(&r, arg, sizeof(struct arpreq));
			if (err)
				return -EFAULT;
			break;
		default:
			return -EINVAL;
	}

	if (r.arp_pa.sa_family != AF_INET)
		return -EPFNOSUPPORT;

	if (!(r.arp_flags & ATF_PUBL) &&
	    (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
		return -EINVAL;
	if (!(r.arp_flags & ATF_NETMASK))
		((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr=__constant_htonl(0xFFFFFFFFUL);

	rtnl_lock();
	if (r.arp_dev[0]) {
		err = -ENODEV;
		if ((dev = __dev_get_by_name(r.arp_dev)) == NULL)
			goto out;

		/* Mmmm... It is wrong... ARPHRD_NETROM==0 */
		if (!r.arp_ha.sa_family)
			r.arp_ha.sa_family = dev->type;
		err = -EINVAL;
		if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
			goto out;
	} else if (cmd == SIOCGARP) {
		err = -ENODEV;
		goto out;
	}

	switch(cmd) {
	case SIOCDARP:
	        err = arp_req_delete(&r, dev);
		break;
	case SIOCSARP:
		err = arp_req_set(&r, dev);
		break;
	case SIOCGARP:
		err = arp_req_get(&r, dev);
		if (!err && copy_to_user(arg, &r, sizeof(r)))
			err = -EFAULT;
		break;
	}
out:
	rtnl_unlock();
	return err;
}

/*
 *	Write the contents of the ARP cache to a PROCfs file.
 */
#ifndef CONFIG_PROC_FS
static int arp_get_info(char *buffer, char **start, off_t offset, int length) { return 0; }
#else
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
static char *ax2asc2(ax25_address *a, char *buf);
#endif
#define HBUFFERLEN 30

static int arp_get_info(char *buffer, char **start, off_t offset, int length)
{
	int len=0;
	off_t pos=0;
	int size;
	char hbuffer[HBUFFERLEN];
	int i,j,k;
	const char hexbuf[] =  "0123456789ABCDEF";

	size = sprintf(buffer,"IP address       HW type     Flags       HW address            Mask     Device\n");

	pos+=size;
	len+=size;

	for(i=0; i<=NEIGH_HASHMASK; i++) {
		struct neighbour *n;
		read_lock_bh(&arp_tbl.lock);
		for (n=arp_tbl.hash_buckets[i]; n; n=n->next) {
			struct net_device *dev = n->dev;
			int hatype = dev->type;

			/* Do not confuse users "arp -a" with magic entries */
			if (!(n->nud_state&~NUD_NOARP))
				continue;

			read_lock(&n->lock);

/*
 *	Convert hardware address to XX:XX:XX:XX ... form.
 */
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
			if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
				ax2asc2((ax25_address *)n->ha, hbuffer);
			else {
#endif
			for (k=0,j=0;k<HBUFFERLEN-3 && j<dev->addr_len;j++) {
				hbuffer[k++]=hexbuf[(n->ha[j]>>4)&15 ];
				hbuffer[k++]=hexbuf[n->ha[j]&15     ];
				hbuffer[k++]=':';
			}
			hbuffer[--k]=0;

#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
		}
#endif

			{
				char tbuf[16];
				sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key));
				size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s"
							"     *        %s\n",
					tbuf,
					hatype,
					arp_state_to_flags(n), 
					hbuffer,
					dev->name);
			}

			read_unlock(&n->lock);

			len += size;
			pos += size;
		  
			if (pos <= offset)
				len=0;
			if (pos >= offset+length) {
				read_unlock_bh(&arp_tbl.lock);
 				goto done;
			}
		}
		read_unlock_bh(&arp_tbl.lock);
	}

	for (i=0; i<=PNEIGH_HASHMASK; i++) {
		struct pneigh_entry *n;
		for (n=arp_tbl.phash_buckets[i]; n; n=n->next) {
			struct net_device *dev = n->dev;
			int hatype = dev ? dev->type : 0;

			{
				char tbuf[16];
				sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key));
				size = sprintf(buffer+len, "%-16s 0x%-10x0x%-10x%s"
							"     *        %s\n",
					tbuf,
					hatype,
 					ATF_PUBL|ATF_PERM,
					"00:00:00:00:00:00",
					dev ? dev->name : "*");
			}

			len += size;
			pos += size;
		  
			if (pos <= offset)
				len=0;
			if (pos >= offset+length)
				goto done;
		}
	}

done:
  
	*start = buffer+len-(pos-offset);	/* Start of wanted data */
	len = pos-offset;			/* Start slop */
	if (len>length)
		len = length;			/* Ending slop */
	if (len<0)
		len = 0;
	return len;
}
#endif

/* Note, that it is not on notifier chain.
   It is necessary, that this routine was called after route cache will be
   flushed.
 */
void arp_ifdown(struct net_device *dev)
{
	neigh_ifdown(&arp_tbl, dev);
}


/*
 *	Called once on startup.
 */

static struct packet_type arp_packet_type = {
	type:	__constant_htons(ETH_P_ARP),
	func:	arp_rcv,
	data:	(void*) 1, /* understand shared skbs */
};

void __init arp_init (void)
{
	neigh_table_init(&arp_tbl);

	dev_add_pack(&arp_packet_type);

	proc_net_create ("arp", 0, arp_get_info);

#ifdef CONFIG_SYSCTL
	neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, NET_IPV4_NEIGH, "ipv4");
#endif
}


#ifdef CONFIG_PROC_FS
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)

/*
 *	ax25 -> ASCII conversion
 */
char *ax2asc2(ax25_address *a, char *buf)
{
	char c, *s;
	int n;

	for (n = 0, s = buf; n < 6; n++) {
		c = (a->ax25_call[n] >> 1) & 0x7F;

		if (c != ' ') *s++ = c;
	}
	
	*s++ = '-';

	if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
		*s++ = '1';
		n -= 10;
	}
	
	*s++ = n + '0';
	*s++ = '\0';

	if (*buf == '\0' || *buf == '-')
	   return "*";

	return buf;

}

#endif
#endif