patch-2.1.99 linux/net/econet/econet.c

Next file: linux/net/ethernet/Makefile
Previous file: linux/net/econet/Makefile
Back to the patch index
Back to the overall index

diff -u --recursive --new-file v2.1.98/linux/net/econet/econet.c linux/net/econet/econet.c
@@ -0,0 +1,1108 @@
+/*
+ *	An implementation of the Acorn Econet and AUN protocols.
+ *	Philip Blundell <philb@gnu.org>
+ *
+ *	Fixes:
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/if_ether.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/route.h>
+#include <linux/inet.h>
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/if_ec.h>
+#include <net/udp.h>
+#include <net/ip.h>
+#include <asm/spinlock.h>
+#include <linux/inetdevice.h>
+
+static struct proto_ops econet_ops;
+static struct sock *econet_sklist;
+
+#ifdef CONFIG_ECONET_AUNUDP
+static struct socket *udpsock;
+#define AUN_PORT	0x8000
+
+struct aunhdr
+{
+	unsigned char code;		/* AUN magic protocol byte */
+	unsigned char port;
+	unsigned char cb;
+	unsigned char pad;
+	unsigned long handle;
+};
+
+static unsigned long aun_seq = 0;
+
+/* Queue of packets waiting to be transmitted. */
+static struct sk_buff_head aun_queue;
+static struct timer_list ab_cleanup_timer;
+
+#endif		/* CONFIG_ECONET_AUNUDP */
+
+/* Per-packet information */
+struct ec_cb
+{
+	struct sockaddr_ec sec;
+	unsigned long cookie;		/* Supplied by user. */
+#ifdef CONFIG_ECONET_AUNUDP
+	int done;
+	unsigned long seq;		/* Sequencing */
+	unsigned long timeout;		/* Timeout */
+	unsigned long start;		/* jiffies */
+#endif
+#ifdef CONFIG_ECONET_NATIVE
+	void (*sent)(struct sk_buff *, int result);
+#endif
+};
+
+struct ec_device
+{
+	struct device *dev;		/* Real device structure */
+	unsigned char station, net;	/* Econet protocol address */
+	struct ec_device *prev, *next;	/* Linked list */
+};
+
+static struct ec_device *edevlist = NULL;
+
+static spinlock_t edevlist_lock;
+
+/*
+ *	Faster version of edev_get - call with IRQs off
+ */
+
+static __inline__ struct ec_device *__edev_get(struct device *dev)
+{
+	struct ec_device *edev;
+	for (edev = edevlist; edev; edev = edev->next)
+	{
+		if (edev->dev == dev)
+			break;
+	}
+	return edev;
+}
+
+/*
+ *	Find an Econet device given its `dev' pointer.  This is IRQ safe.
+ */
+
+static struct ec_device *edev_get(struct device *dev)
+{
+	struct ec_device *edev;
+	unsigned long flags;
+	spin_lock_irqsave(&edevlist_lock, flags);
+	edev = __edev_get(dev);
+	spin_unlock_irqrestore(&edevlist_lock, flags);
+	return edev;
+}
+
+/*
+ *	Pull a packet from our receive queue and hand it to the user.
+ *	If necessary we block.
+ */
+
+static int econet_recvmsg(struct socket *sock, struct msghdr *msg, int len,
+			  int flags, struct scm_cookie *scm)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	int copied, err;
+
+	msg->msg_namelen = sizeof(struct sockaddr_ec);
+
+	/*
+	 *	Call the generic datagram receiver. This handles all sorts
+	 *	of horrible races and re-entrancy so we can forget about it
+	 *	in the protocol layers.
+	 *
+	 *	Now it will return ENETDOWN, if device have just gone down,
+	 *	but then it will block.
+	 */
+
+	skb=skb_recv_datagram(sk,flags,flags&MSG_DONTWAIT,&err);
+
+	/*
+	 *	An error occurred so return it. Because skb_recv_datagram() 
+	 *	handles the blocking we don't see and worry about blocking
+	 *	retries.
+	 */
+
+	if(skb==NULL)
+		goto out;
+
+	/*
+	 *	You lose any data beyond the buffer you gave. If it worries a
+	 *	user program they can ask the device for its MTU anyway.
+	 */
+
+	copied = skb->len;
+	if (copied > len)
+	{
+		copied=len;
+		msg->msg_flags|=MSG_TRUNC;
+	}
+
+	/* We can't use skb_copy_datagram here */
+	err = memcpy_toiovec(msg->msg_iov, skb->data, copied);
+	if (err)
+		goto out_free;
+	sk->stamp=skb->stamp;
+
+	if (msg->msg_name)
+		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
+
+	/*
+	 *	Free or return the buffer as appropriate. Again this
+	 *	hides all the races and re-entrancy issues from us.
+	 */
+	err = copied;
+
+out_free:
+	skb_free_datagram(sk, skb);
+out:
+	return err;
+}
+
+/*
+ *	Bind an Econet socket.
+ */
+
+static int econet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sockaddr_ec *sec = (struct sockaddr_ec *)uaddr;
+	struct sock *sk=sock->sk;
+	
+	/*
+	 *	Check legality
+	 */
+	 
+	if (addr_len < sizeof(struct sockaddr_ec))
+		return -EINVAL;
+	if (sec->sec_family != AF_ECONET)
+		return -EINVAL;
+	
+	sk->protinfo.af_econet->cb = sec->cb;
+	sk->protinfo.af_econet->port = sec->port;
+	sk->protinfo.af_econet->station = sec->addr.station;
+	sk->protinfo.af_econet->net = sec->addr.net;
+
+	return 0;
+}
+
+/*
+ *	Queue a transmit result for the user to be told about.
+ */
+
+static void tx_result(struct sock *sk, unsigned long cookie, int result)
+{
+	struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
+	struct ec_cb *eb;
+	struct sockaddr_ec *sec;
+
+	if (skb == NULL)
+	{
+		printk(KERN_DEBUG "ec: memory squeeze, transmit result dropped.\n");
+		return;
+	}
+
+	eb = (struct ec_cb *)&skb->cb;
+	sec = (struct sockaddr_ec *)&eb->sec;
+	memset(sec, 0, sizeof(struct sockaddr_ec));
+	sec->cookie = cookie;
+	sec->type = ECTYPE_TRANSMIT_STATUS | result;
+	sec->sec_family = AF_ECONET;
+
+	if (sock_queue_rcv_skb(sk, skb) < 0)
+		kfree_skb(skb);
+}
+
+#ifdef CONFIG_ECONET_NATIVE
+/*
+ *	Called by the Econet hardware driver when a packet transmit
+ *	has completed.  Tell the user.
+ */
+
+static void ec_tx_done(struct sk_buff *skb, int result)
+{
+	struct ec_cb *eb = (struct ec_cb *)&skb->cb;
+	tx_result(skb->sk, eb->cookie, result);
+}
+#endif
+
+/*
+ *	Send a packet.  We have to work out which device it's going out on
+ *	and hence whether to use real Econet or the UDP emulation.
+ */
+
+static int econet_sendmsg(struct socket *sock, struct msghdr *msg, int len,
+			  struct scm_cookie *scm)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_ec *saddr=(struct sockaddr_ec *)msg->msg_name;
+	struct device *dev;
+	struct ec_addr addr;
+	struct ec_device *edev;
+	int err;
+	unsigned char port, cb;
+	struct sk_buff *skb;
+	struct ec_cb *eb;
+#ifdef CONFIG_ECONET_NATIVE
+	unsigned short proto = 0;
+#endif
+#ifdef CONFIG_ECONET_AUNUDP
+	struct msghdr udpmsg;
+	struct iovec iov[msg->msg_iovlen+1];
+	struct aunhdr ah;
+	struct sockaddr_in udpdest;
+	__kernel_size_t size;
+	int i;
+	mm_segment_t oldfs;
+#endif
+		
+	/*
+	 *	Check the flags. 
+	 */
+
+	if (msg->msg_flags&~MSG_DONTWAIT) 
+		return(-EINVAL);
+
+	/*
+	 *	Get and verify the address. 
+	 */
+	 
+	if (saddr == NULL) {
+		addr.station = sk->protinfo.af_econet->station;
+		addr.net = sk->protinfo.af_econet->net;
+		port = sk->protinfo.af_econet->port;
+		cb = sk->protinfo.af_econet->cb;
+	} else {
+		if (msg->msg_namelen < sizeof(struct sockaddr_ec)) 
+			return -EINVAL;
+		addr.station = saddr->addr.station;
+		addr.net = saddr->addr.net;
+		port = saddr->port;
+		cb = saddr->cb;
+	}
+
+	/* Look for a device with the right network number. */
+	for (edev = edevlist; edev && (edev->net != addr.net); 
+	     edev = edev->next);
+
+	/* Bridge?  What's that? */
+	if (edev == NULL) 
+		return -ENETUNREACH;
+
+	dev = edev->dev;
+
+	if (dev->type == ARPHRD_ECONET)
+	{
+		/* Real hardware Econet.  We're not worthy etc. */
+#ifdef CONFIG_ECONET_NATIVE
+		unsigned char *p;
+
+		dev_lock_list();
+		
+		skb = sock_alloc_send_skb(sk, len+dev->hard_header_len+15, 0, 
+					  msg->msg_flags & MSG_DONTWAIT, &err);
+		if (skb==NULL)
+			goto out_unlock;
+		
+		skb_reserve(skb, (dev->hard_header_len+15)&~15);
+		skb->nh.raw = skb->data;
+		
+		eb = (struct ec_cb *)&skb->cb;
+		
+		eb->cookie = saddr->cookie;
+		eb->sec = *saddr;
+		eb->sent - ec_tx_done;
+
+		if (dev->hard_header) {
+			int res;
+			err = -EINVAL;
+			res = dev->hard_header(skb, dev, ntohs(proto), &addr, NULL, len);
+			if (sock->type != SOCK_DGRAM) {
+				skb->tail = skb->data;
+				skb->len = 0;
+			} else if (res < 0)
+				goto out_free;
+		}
+		
+		/* Copy the data. Returns -EFAULT on error */
+		err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
+		skb->protocol = proto;
+		skb->dev = dev;
+		skb->priority = sk->priority;
+		if (err)
+			goto out_free;
+		
+		err = -ENETDOWN;
+		if (!(dev->flags & IFF_UP))
+			goto out_free;
+		
+		/*
+		 *	Now send it
+		 */
+		
+		dev_unlock_list();
+		dev_queue_xmit(skb);
+		return(len);
+
+	out_free:
+		kfree_skb(skb);
+	out_unlock:
+		dev_unlock_list();
+#else
+		err = -EPROTOTYPE;
+#endif
+		return err;
+	}
+
+#ifdef CONFIG_ECONET_AUNUDP
+	/* AUN virtual Econet. */
+
+	if (udpsock == NULL)
+		return -ENETDOWN;		/* No socket - can't send */
+	
+	/* Make up a UDP datagram and hand it off to some higher intellect. */
+
+	memset(&udpdest, 0, sizeof(udpdest));
+	udpdest.sin_family = AF_INET;
+	udpdest.sin_port = htons(AUN_PORT);
+
+	/* At the moment we use the stupid Acorn scheme of Econet address
+	   y.x maps to IP a.b.c.x.  This should be replaced with something
+	   more flexible and more aware of subnet masks.  */
+	{
+		struct in_device *idev = (struct in_device *)dev->ip_ptr;
+		unsigned long network = ntohl(idev->ifa_list->ifa_address) & 
+			0xffffff00;		/* !!! */
+		udpdest.sin_addr.s_addr = htonl(network | addr.station);
+	}
+
+	ah.port = port;
+	ah.cb = cb & 0x7f;
+	ah.code = 2;		/* magic */
+	ah.pad = 0;
+
+	/* tack our header on the front of the iovec */
+	size = sizeof(struct aunhdr);
+	iov[0].iov_base = (void *)&ah;
+	iov[0].iov_len = size;
+	for (i = 0; i < msg->msg_iovlen; i++) {
+		void *base = msg->msg_iov[i].iov_base;
+		size_t len = msg->msg_iov[i].iov_len;
+		/* Check it now since we switch to KERNEL_DS later. */
+		if ((err = verify_area(VERIFY_READ, base, len)) < 0)
+			return err;
+		iov[i+1].iov_base = base;
+		iov[i+1].iov_len = len;
+		size += len;
+	}
+
+	/* Get a skbuff (no data, just holds our cb information) */
+	if ((skb = sock_alloc_send_skb(sk, 0, 0, 
+			     msg->msg_flags & MSG_DONTWAIT, &err)) == NULL)
+		return err;
+
+	eb = (struct ec_cb *)&skb->cb;
+
+	eb->cookie = saddr->cookie;
+	eb->timeout = (5*HZ);
+	eb->start = jiffies;
+	ah.handle = aun_seq;
+	eb->seq = (aun_seq++);
+	eb->sec = *saddr;
+
+	skb_queue_tail(&aun_queue, skb);
+
+	udpmsg.msg_name = (void *)&udpdest;
+	udpmsg.msg_namelen = sizeof(udpdest);
+	udpmsg.msg_iov = &iov[0];
+	udpmsg.msg_iovlen = msg->msg_iovlen + 1;
+	udpmsg.msg_control = NULL;
+	udpmsg.msg_controllen = 0;
+	udpmsg.msg_flags=0;
+
+	oldfs = get_fs(); set_fs(KERNEL_DS);	/* More privs :-) */
+	err = sock_sendmsg(udpsock, &udpmsg, size);
+	set_fs(oldfs);
+#else
+	err = -EPROTOTYPE;
+#endif
+	return err;
+}
+
+/*
+ *	Look up the address of a socket.
+ */
+
+static int econet_getname(struct socket *sock, struct sockaddr *uaddr,
+			  int *uaddr_len, int peer)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_ec *sec = (struct sockaddr_ec *)uaddr;
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	sec->sec_family = AF_ECONET;
+	sec->port = sk->protinfo.af_econet->port;
+	sec->addr.station = sk->protinfo.af_econet->station;
+	sec->addr.net = sk->protinfo.af_econet->net;
+
+	*uaddr_len = sizeof(*sec);
+	return 0;
+}
+
+static void econet_destroy_timer(unsigned long data)
+{
+	struct sock *sk=(struct sock *)data;
+
+	if (!atomic_read(&sk->wmem_alloc) && !atomic_read(&sk->rmem_alloc)) {
+		sk_free(sk);
+		MOD_DEC_USE_COUNT;
+		return;
+	}
+
+	sk->timer.expires=jiffies+10*HZ;
+	add_timer(&sk->timer);
+	printk(KERN_DEBUG "econet socket destroy delayed\n");
+}
+
+/*
+ *	Close an econet socket.
+ */
+
+static int econet_release(struct socket *sock, struct socket *peersock)
+{
+	struct sk_buff	*skb;
+	struct sock *sk = sock->sk;
+
+	if (!sk)
+		return 0;
+
+	sklist_remove_socket(&econet_sklist, sk);
+
+	/*
+	 *	Now the socket is dead. No more input will appear.
+	 */
+
+	sk->state_change(sk);	/* It is useless. Just for sanity. */
+
+	sock->sk = NULL;
+	sk->socket = NULL;
+	sk->dead = 1;
+
+	/* Purge queues */
+
+	while ((skb=skb_dequeue(&sk->receive_queue))!=NULL)
+		kfree_skb(skb);
+
+	if (atomic_read(&sk->rmem_alloc) || atomic_read(&sk->wmem_alloc)) {
+		sk->timer.data=(unsigned long)sk;
+		sk->timer.expires=jiffies+HZ;
+		sk->timer.function=econet_destroy_timer;
+		add_timer(&sk->timer);
+		return 0;
+	}
+
+	sk_free(sk);
+	MOD_DEC_USE_COUNT;
+	return 0;
+}
+
+/*
+ *	Create an Econet socket
+ */
+
+static int econet_create(struct socket *sock, int protocol)
+{
+	struct sock *sk;
+	int err;
+
+	/* Econet only provides datagram services. */
+	if (sock->type != SOCK_DGRAM)
+		return -ESOCKTNOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+	MOD_INC_USE_COUNT;
+
+	err = -ENOBUFS;
+	sk = sk_alloc(AF_ECONET, GFP_KERNEL, 1);
+	if (sk == NULL)
+		goto out;
+
+	sk->reuse = 1;
+	sock->ops = &econet_ops;
+	sock_init_data(sock,sk);
+
+	sk->protinfo.af_econet = kmalloc(sizeof(struct econet_opt), GFP_KERNEL);
+	if (sk->protinfo.af_econet == NULL)
+		goto out_free;
+	memset(sk->protinfo.af_econet, 0, sizeof(struct econet_opt));
+	sk->zapped=0;
+	sk->family = AF_ECONET;
+	sk->num = protocol;
+
+	sklist_insert_socket(&econet_sklist, sk);
+	return(0);
+
+out_free:
+	sk_free(sk);
+out:
+	MOD_DEC_USE_COUNT;
+	return err;
+}
+
+/*
+ *	Handle Econet specific ioctls
+ */
+
+static int ec_dev_ioctl(struct socket *sock, unsigned int cmd, void *arg)
+{
+	struct ifreq ifr;
+	struct ec_device *edev;
+	struct device *dev;
+	unsigned long flags;
+	struct sockaddr_ec *sec;
+
+	/*
+	 *	Fetch the caller's info block into kernel space
+	 */
+
+	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
+		return -EFAULT;
+
+	if ((dev = dev_get(ifr.ifr_name)) == NULL) 
+		return -ENODEV;
+
+	sec = (struct sockaddr_ec *)&ifr.ifr_addr;
+
+	switch (cmd)
+	{
+	case SIOCSIFADDR:
+		spin_lock_irqsave(&edevlist_lock, flags);
+		edev = __edev_get(dev);
+		if (edev == NULL)
+		{
+			/* Magic up a new one. */
+			edev = kmalloc(GFP_KERNEL, sizeof(struct ec_device));
+			if (edev == NULL) {
+				printk("af_ec: memory squeeze.\n");
+				spin_unlock_irqrestore(&edevlist_lock, flags);
+				return -ENOMEM;
+			}
+			memset(edev, 0, sizeof(struct ec_device));
+			edev->dev = dev;
+			edev->next = edevlist;
+			edevlist = edev;
+		}
+		edev->station = sec->addr.station;
+		edev->net = sec->addr.net;
+		spin_unlock_irqrestore(&edevlist_lock, flags);
+		return 0;
+
+	case SIOCGIFADDR:
+		spin_lock_irqsave(&edevlist_lock, flags);
+		edev = __edev_get(dev);
+		if (edev == NULL)
+		{
+			spin_unlock_irqrestore(&edevlist_lock, flags);
+			return -ENODEV;
+		}
+		memset(sec, 0, sizeof(struct sockaddr_ec));
+		sec->addr.station = edev->station;
+		sec->addr.net = edev->net;
+		sec->sec_family = AF_ECONET;
+		spin_unlock_irqrestore(&edevlist_lock, flags);
+		if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
+			return -EFAULT;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/*
+ *	Handle generic ioctls
+ */
+
+static int econet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+	int err;
+	int pid;
+
+	switch(cmd) 
+	{
+		case FIOSETOWN:
+		case SIOCSPGRP:
+			err = get_user(pid, (int *) arg);
+			if (err)
+				return err; 
+			if (current->pid != pid && current->pgrp != -pid && !suser())
+				return -EPERM;
+			sk->proc = pid;
+			return(0);
+		case FIOGETOWN:
+		case SIOCGPGRP:
+			return put_user(sk->proc, (int *)arg);
+		case SIOCGSTAMP:
+			if(sk->stamp.tv_sec==0)
+				return -ENOENT;
+			err = -EFAULT;
+			if (!copy_to_user((void *)arg, &sk->stamp, sizeof(struct timeval)))
+				err = 0;
+			return err;
+		case SIOCGIFFLAGS:
+		case SIOCSIFFLAGS:
+		case SIOCGIFCONF:
+		case SIOCGIFMETRIC:
+		case SIOCSIFMETRIC:
+		case SIOCGIFMEM:
+		case SIOCSIFMEM:
+		case SIOCGIFMTU:
+		case SIOCSIFMTU:
+		case SIOCSIFLINK:
+		case SIOCGIFHWADDR:
+		case SIOCSIFHWADDR:
+		case SIOCSIFMAP:
+		case SIOCGIFMAP:
+		case SIOCSIFSLAVE:
+		case SIOCGIFSLAVE:
+		case SIOCGIFINDEX:
+		case SIOCGIFNAME:
+		case SIOCGIFCOUNT:
+		case SIOCSIFHWBROADCAST:
+			return(dev_ioctl(cmd,(void *) arg));
+
+
+		case SIOCSIFADDR:
+		case SIOCGIFADDR:
+			return ec_dev_ioctl(sock, cmd, (void *)arg);
+			break;
+
+		default:
+			if ((cmd >= SIOCDEVPRIVATE) &&
+			    (cmd <= (SIOCDEVPRIVATE + 15)))
+				return(dev_ioctl(cmd,(void *) arg));
+
+#ifdef CONFIG_NET_RADIO
+			if((cmd >= SIOCIWFIRST) && (cmd <= SIOCIWLAST))
+				return(dev_ioctl(cmd,(void *) arg));
+#endif
+			return -EOPNOTSUPP;
+	}
+	/*NOTREACHED*/
+	return 0;
+}
+
+static struct net_proto_family econet_family_ops = {
+	AF_ECONET,
+	econet_create
+};
+
+static struct proto_ops econet_ops = {
+	AF_ECONET,
+
+	sock_no_dup,
+	econet_release,
+	econet_bind,
+	sock_no_connect,
+	NULL,
+	NULL,
+	econet_getname, 
+	datagram_poll,
+	econet_ioctl,
+	sock_no_listen,
+	sock_no_shutdown,
+	sock_no_setsockopt,
+	sock_no_getsockopt,
+	sock_no_fcntl,
+	econet_sendmsg,
+	econet_recvmsg
+};
+
+/*
+ *	Find the listening socket, if any, for the given data.
+ */
+
+static struct sock *ec_listening_socket(unsigned char port, unsigned char
+					station, unsigned char net)
+{
+	struct sock *sk = econet_sklist;
+
+	while (sk)
+	{
+		struct econet_opt *opt = sk->protinfo.af_econet;
+		if ((opt->port == port || opt->port == 0) && 
+		    (opt->station == station || opt->station == 0) &&
+		    (opt->net == net || opt->net == 0))
+			return sk;
+		sk = sk->sklist_next;
+	}
+
+	return NULL;
+}
+
+#ifdef CONFIG_ECONET_AUNUDP
+
+/*
+ *	Send an AUN protocol response. 
+ */
+
+static void aun_send_response(__u32 addr, unsigned long seq, int code, int cb)
+{
+	struct sockaddr_in sin;
+	struct iovec iov;
+	struct aunhdr ah;
+	struct msghdr udpmsg;
+	int err;
+	mm_segment_t oldfs;
+	
+	memset(&sin, 0, sizeof(sin));
+	sin.sin_family = AF_INET;
+	sin.sin_port = htons(AUN_PORT);
+	sin.sin_addr.s_addr = addr;
+
+	ah.code = code;
+	ah.pad = 0;
+	ah.port = 0;
+	ah.cb = cb;
+	ah.handle = seq;
+
+	iov.iov_base = (void *)&ah;
+	iov.iov_len = sizeof(ah);
+
+	udpmsg.msg_name = (void *)&sin;
+	udpmsg.msg_namelen = sizeof(sin);
+	udpmsg.msg_iov = &iov;
+	udpmsg.msg_iovlen = 1;
+	udpmsg.msg_control = NULL;
+	udpmsg.msg_controllen = 0;
+	udpmsg.msg_flags=0;
+
+	oldfs = get_fs(); set_fs(KERNEL_DS);
+	err = sock_sendmsg(udpsock, &udpmsg, sizeof(ah));
+	set_fs(oldfs);
+}
+
+/*
+ *	Handle incoming AUN packets.  Work out if anybody wants them,
+ *	and send positive or negative acknowledgements as appropriate.
+ */
+
+static void aun_incoming(struct sk_buff *skb, struct aunhdr *ah, size_t len)
+{
+	struct ec_device *edev = edev_get(skb->dev);
+	struct iphdr *ip = skb->nh.iph;
+	unsigned char stn = ntohl(ip->saddr) & 0xff;
+	struct sock *sk;
+	struct sk_buff *newskb;
+	struct ec_cb *eb;
+	struct sockaddr_ec *sec;
+
+	if (edev == NULL)
+		return;		/* Device not configured for AUN */
+	
+	if ((sk = ec_listening_socket(ah->port, stn, edev->net)) == NULL)
+		goto bad;		/* Nobody wants it */
+
+	newskb = alloc_skb((len - sizeof(struct aunhdr) + 15) & ~15, 
+			   GFP_ATOMIC);
+	if (newskb == NULL)
+	{
+		printk(KERN_DEBUG "AUN: memory squeeze, dropping packet.\n");
+		/* Send nack and hope sender tries again */
+		goto bad;
+	}
+
+	eb = (struct ec_cb *)&newskb->cb;
+	sec = (struct sockaddr_ec *)&eb->sec;
+	memset(sec, 0, sizeof(struct sockaddr_ec));
+	sec->sec_family = AF_ECONET;
+	sec->type = ECTYPE_PACKET_RECEIVED;
+	sec->port = ah->port;
+	sec->cb = ah->cb;
+	sec->addr.net = edev->net;
+	sec->addr.station = stn;
+
+	memcpy(skb_put(newskb, len - sizeof(struct aunhdr)), (void *)(ah+1), 
+	       len - sizeof(struct aunhdr));
+
+	if (sock_queue_rcv_skb(sk, newskb) < 0)
+	{
+		/* Socket is bankrupt. */
+		kfree_skb(newskb);
+		goto bad;
+	}
+
+	aun_send_response(ip->saddr, ah->handle, 3, 0);
+	return;
+
+bad:
+	aun_send_response(ip->saddr, ah->handle, 4, 0);
+}
+
+/*
+ *	Handle incoming AUN transmit acknowledgements.  If the sequence
+ *      number matches something in our backlog then kill it and tell
+ *	the user.  If the remote took too long to reply then we may have
+ *	dropped the packet already.
+ */
+
+static void aun_tx_ack(unsigned long seq, int result)
+{
+	struct sk_buff *skb;
+	unsigned long flags;
+	struct ec_cb *eb;
+
+	spin_lock_irqsave(&aun_queue_lock, flags);
+	skb = skb_peek(&aun_queue);
+	while (skb && skb != (struct sk_buff *)&aun_queue)
+	{
+		struct sk_buff *newskb = skb->next;
+		eb = (struct ec_cb *)&skb->cb;
+		if (eb->seq == seq)
+			goto foundit;
+
+		skb = newskb;
+	}
+	spin_unlock_irqrestore(&aun_queue_lock, flags);
+	printk(KERN_DEBUG "AUN: unknown sequence %ld\n", seq);
+	return;
+
+foundit:
+	tx_result(skb->sk, eb->cookie, result);
+	skb_unlink(skb);
+	spin_unlock_irqrestore(&aun_queue_lock, flags);
+}
+
+/*
+ *	Deal with received AUN frames - sort out what type of thing it is
+ *	and hand it to the right function.
+ */
+
+static void aun_data_available(struct sock *sk, int slen)
+{
+	int err;
+	struct sk_buff *skb;
+	unsigned char *data;
+	struct aunhdr *ah;
+	struct iphdr *ip;
+	size_t len;
+
+	while ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL) {
+		if (err == -EAGAIN) {
+			printk(KERN_ERR "AUN: no data available?!");
+			return;
+		}
+		printk(KERN_DEBUG "AUN: recvfrom() error %d\n", -err);
+	}
+
+	data = skb->h.raw + sizeof(struct udphdr);
+	ah = (struct aunhdr *)data;
+	len = skb->len - sizeof(struct udphdr);
+	ip = skb->nh.iph;
+
+	switch (ah->code)
+	{
+	case 2:
+		aun_incoming(skb, ah, len);
+		break;
+	case 3:
+		aun_tx_ack(ah->handle, ECTYPE_TRANSMIT_OK);
+		break;
+	case 4:
+		aun_tx_ack(ah->handle, ECTYPE_TRANSMIT_NOT_LISTENING);
+		break;
+#if 0
+		/* This isn't quite right yet. */
+	case 5:
+		aun_send_response(ip->saddr, ah->handle, 6, ah->cb);
+		break;
+#endif
+	default:
+		printk(KERN_DEBUG "unknown AUN packet (type %d)\n", data[0]);
+	}
+
+	skb_free_datagram(sk, skb);
+}
+
+/*
+ *	Called by the timer to manage the AUN transmit queue.  If a packet
+ *	was sent to a dead or nonexistent host then we will never get an
+ *	acknowledgement back.  After a few seconds we need to spot this and
+ *	drop the packet.
+ */
+
+static spinlock_t aun_queue_lock;
+
+static void ab_cleanup(unsigned long h)
+{
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	spin_lock_irqsave(&aun_queue_lock, flags);
+	skb = skb_peek(&aun_queue);
+	while (skb && skb != (struct sk_buff *)&aun_queue)
+	{
+		struct sk_buff *newskb = skb->next;
+		struct ec_cb *eb = (struct ec_cb *)&skb->cb;
+		if ((jiffies - eb->start) > eb->timeout)
+		{
+			tx_result(skb->sk, eb->cookie, 
+				  ECTYPE_TRANSMIT_NOT_PRESENT);
+			skb_unlink(skb);
+		}
+		skb = newskb;
+	}
+	spin_unlock_irqrestore(&aun_queue_lock, flags);
+
+	mod_timer(&ab_cleanup_timer, jiffies + (HZ*2));
+}
+
+__initfunc(static int aun_udp_initialise(void))
+{
+	int error;
+	struct sockaddr_in sin;
+
+	skb_queue_head_init(&aun_queue);
+	spin_lock_init(&aun_queue_lock);
+	init_timer(&ab_cleanup_timer);
+	ab_cleanup_timer.expires = jiffies + (HZ*2);
+	ab_cleanup_timer.function = ab_cleanup;
+	add_timer(&ab_cleanup_timer);
+
+	memset(&sin, 0, sizeof(sin));
+	sin.sin_port = htons(AUN_PORT);
+
+	/* We can count ourselves lucky Acorn machines are too dim to
+	   speak IPv6. :-) */
+	if ((error = sock_create(AF_INET, SOCK_DGRAM, 0, &udpsock)) < 0)
+	{
+		printk("AUN: socket error %d\n", -error);
+		return error;
+	}
+	
+	udpsock->sk->reuse = 1;
+	udpsock->sk->allocation = GFP_ATOMIC;	/* we're going to call it
+						   from interrupts */
+	
+	error = udpsock->ops->bind(udpsock, (struct sockaddr *)&sin,
+				sizeof(sin));
+	if (error < 0)
+	{
+		printk("AUN: bind error %d\n", -error);
+		goto release;
+	}
+
+	udpsock->sk->data_ready = aun_data_available;
+
+	return 0;
+
+release:
+	sock_release(udpsock);
+	udpsock = NULL;
+	return error;
+}
+#endif
+
+static int econet_notifier(struct notifier_block *this, unsigned long msg, void *data)
+{
+	struct device *dev = (struct device *)data;
+	struct ec_device *edev;
+	unsigned long flags;
+
+	switch (msg) {
+	case NETDEV_UNREGISTER:
+		/* A device has gone down - kill any data we hold for it. */
+		spin_lock_irqsave(&edevlist_lock, flags);
+		for (edev = edevlist; edev; edev = edev->next)
+		{
+			if (edev->dev == dev)
+			{
+				if (edev->prev)
+					edev->prev->next = edev->next;
+				else
+					edevlist = edev->next;
+				if (edev->next)
+					edev->next->prev = edev->prev;
+				kfree(edev);
+				break;
+			}
+		}
+		spin_unlock_irqrestore(&edevlist_lock, flags);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+struct notifier_block econet_netdev_notifier={
+	econet_notifier,
+	NULL,
+	0
+};
+
+#ifdef MODULE
+void cleanup_module(void)
+{
+#ifdef CONFIG_ECONET_AUNUDP
+	del_timer(&ab_cleanup_timer);
+	if (udpsock)
+		sock_release(udpsock);
+#endif
+	unregister_netdevice_notifier(&econet_netdev_notifier);
+	sock_unregister(econet_family_ops.family);
+	return;
+}
+
+int init_module(void)
+#else
+__initfunc(void econet_proto_init(struct net_proto *pro))
+#endif
+{
+	spin_lock_init(&edevlist_lock);
+	spin_lock_init(&aun_queue_lock);
+	/* Stop warnings from happening on UP systems. */
+	(void)edevlist_lock;
+	(void)aun_queue_lock;
+	sock_register(&econet_family_ops);
+#ifdef CONFIG_ECONET_AUNUDP
+	aun_udp_initialise();
+#endif
+	register_netdevice_notifier(&econet_netdev_notifier);
+#ifdef MODULE
+	return 0;
+#endif
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov