ClabureDB: Classified Bug-Reports Database

   /*
    *        An implementation of the Acorn Econet and AUN protocols.
    *        Philip Blundell <philb@gnu.org>
    *
    *        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/module.h>
  
  #include <linux/types.h>
  #include <linux/kernel.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/wireless.h>
  #include <linux/skbuff.h>
  #include <linux/udp.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 <linux/spinlock.h>
  #include <linux/rcupdate.h>
  #include <linux/bitops.h>
  #include <linux/mutex.h>
  
  #include <asm/uaccess.h>
  #include <asm/system.h>
  
  static const struct proto_ops econet_ops;
  static struct hlist_head econet_sklist;
  static DEFINE_RWLOCK(econet_lock);
  static DEFINE_MUTEX(econet_mutex);
  
  /* Since there are only 256 possible network numbers (or fewer, depends
     how you count) it makes sense to use a simple lookup table. */
  static struct net_device *net2dev_map[256];
  
  #define EC_PORT_IP        0xd2
  
  #ifdef CONFIG_ECONET_AUNUDP
  static DEFINE_SPINLOCK(aun_queue_lock);
  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;
  
  /* 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
  };
  
  static void econet_remove_socket(struct hlist_head *list, struct sock *sk)
  {
         write_lock_bh(&econet_lock);
         sk_del_node_init(sk);
         write_unlock_bh(&econet_lock);
 }
 
 static void econet_insert_socket(struct hlist_head *list, struct sock *sk)
 {
         write_lock_bh(&econet_lock);
         sk_add_node(sk, list);
         write_unlock_bh(&econet_lock);
 }
 
 /*
  *        Pull a packet from our receive queue and hand it to the user.
  *        If necessary we block.
  */
 
 static int econet_recvmsg(struct kiocb *iocb, struct socket *sock,
                           struct msghdr *msg, size_t len, int flags)
 {
         struct sock *sk = sock->sk;
         struct sk_buff *skb;
         size_t copied;
         int err;
 
         msg->msg_namelen = sizeof(struct sockaddr_ec);
 
         mutex_lock(&econet_mutex);
 
         /*
          *        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->sk_stamp = skb->tstamp;
 
         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:
         mutex_unlock(&econet_mutex);
         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;
         struct econet_sock *eo;
 
         /*
          *        Check legality
          */
 
         if (addr_len < sizeof(struct sockaddr_ec) ||
             sec->sec_family != AF_ECONET)
                 return -EINVAL;
 
         mutex_lock(&econet_mutex);
 
         sk = sock->sk;
         eo = ec_sk(sk);
 
         eo->cb            = sec->cb;
         eo->port    = sec->port;
         eo->station = sec->addr.station;
         eo->net            = sec->addr.net;
 
         mutex_unlock(&econet_mutex);
 
         return 0;
 }
 
 #if defined(CONFIG_ECONET_AUNUDP) || defined(CONFIG_ECONET_NATIVE)
 /*
  *        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);
 }
 #endif
 
 #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 kiocb *iocb, struct socket *sock,
                           struct msghdr *msg, size_t len)
 {
         struct sock *sk = sock->sk;
         struct sockaddr_ec *saddr=(struct sockaddr_ec *)msg->msg_name;
         struct net_device *dev;
         struct ec_addr addr;
         int err;
         unsigned char port, cb;
 #if defined(CONFIG_ECONET_AUNUDP) || defined(CONFIG_ECONET_NATIVE)
         struct sk_buff *skb;
         struct ec_cb *eb;
 #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|MSG_CMSG_COMPAT))
                 return -EINVAL;
 
         /*
          *        Get and verify the address.
          */
 
         mutex_lock(&econet_mutex);
 
         if (saddr == NULL) {
                 struct econet_sock *eo = ec_sk(sk);
 
                 addr.station = eo->station;
                 addr.net     = eo->net;
                 port             = eo->port;
                 cb             = eo->cb;
         } else {
                 if (msg->msg_namelen < sizeof(struct sockaddr_ec)) {
                         mutex_unlock(&econet_mutex);
                         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. */
         dev = net2dev_map[addr.net];
 
         /* If not directly reachable, use some default */
         if (dev == NULL) {
                 dev = net2dev_map[0];
                 /* No interfaces at all? */
                 if (dev == NULL) {
                         mutex_unlock(&econet_mutex);
                         return -ENETDOWN;
                 }
         }
 
         if (len + 15 > dev->mtu) {
                 mutex_unlock(&econet_mutex);
                 return -EMSGSIZE;
         }
 
         if (dev->type == ARPHRD_ECONET) {
                 /* Real hardware Econet.  We're not worthy etc. */
 #ifdef CONFIG_ECONET_NATIVE
                 unsigned short proto = 0;
                 int res;
 
                 dev_hold(dev);
 
                 skb = sock_alloc_send_skb(sk, len+LL_ALLOCATED_SPACE(dev),
                                           msg->msg_flags & MSG_DONTWAIT, &err);
                 if (skb==NULL)
                         goto out_unlock;
 
                 skb_reserve(skb, LL_RESERVED_SPACE(dev));
                 skb_reset_network_header(skb);
 
                 eb = (struct ec_cb *)&skb->cb;
 
                 /* BUG: saddr may be NULL */
                 eb->cookie = saddr->cookie;
                 eb->sec = *saddr;
                 eb->sent = ec_tx_done;
 
                 err = -EINVAL;
                 res = dev_hard_header(skb, dev, ntohs(proto), &addr, NULL, len);
                 if (res < 0)
                         goto out_free;
                 if (res > 0) {
                         struct ec_framehdr *fh;
                         /* Poke in our control byte and
                            port number.  Hack, hack.  */
                         fh = (struct ec_framehdr *)(skb->data);
                         fh->cb = cb;
                         fh->port = port;
                         if (sock->type != SOCK_DGRAM) {
                                 skb_reset_tail_pointer(skb);
                                 skb->len = 0;
                         }
                 }
 
                 /* 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->sk_priority;
                 if (err)
                         goto out_free;
 
                 err = -ENETDOWN;
                 if (!(dev->flags & IFF_UP))
                         goto out_free;
 
                 /*
                  *        Now send it
                  */
 
                 dev_queue_xmit(skb);
                 dev_put(dev);
                 mutex_unlock(&econet_mutex);
                 return(len);
 
         out_free:
                 kfree_skb(skb);
         out_unlock:
                 if (dev)
                         dev_put(dev);
 #else
                 err = -EPROTOTYPE;
 #endif
                 mutex_unlock(&econet_mutex);
 
                 return err;
         }
 
 #ifdef CONFIG_ECONET_AUNUDP
         /* AUN virtual Econet. */
 
         if (udpsock == NULL) {
                 mutex_unlock(&econet_mutex);
                 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;
                 unsigned long network = 0;
 
                 rcu_read_lock();
                 idev = __in_dev_get_rcu(dev);
                 if (idev) {
                         if (idev->ifa_list)
                                 network = ntohl(idev->ifa_list->ifa_address) &
                                         0xffffff00;                /* !!! */
                 }
                 rcu_read_unlock();
                 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);
         /*
          * XXX: that is b0rken.  We can't mix userland and kernel pointers
          * in iovec, since on a lot of platforms copy_from_user() will
          * *not* work with the kernel and userland ones at the same time,
          * regardless of what we do with set_fs().  And we are talking about
          * econet-over-ethernet here, so "it's only ARM anyway" doesn't
          * apply.  Any suggestions on fixing that code?                -- AV
          */
         iov[0].iov_base = (void *)&ah;
         iov[0].iov_len = size;
         for (i = 0; i < msg->msg_iovlen; i++) {
                 void __user *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 (!access_ok(VERIFY_READ, base, len)) {
                         mutex_unlock(&econet_mutex);
                         return -EFAULT;
                 }
                 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,
                                        msg->msg_flags & MSG_DONTWAIT,
                                        &err)) == NULL) {
                 mutex_unlock(&econet_mutex);
                 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
         mutex_unlock(&econet_mutex);
 
         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;
         struct econet_sock *eo;
         struct sockaddr_ec *sec = (struct sockaddr_ec *)uaddr;
 
         if (peer)
                 return -EOPNOTSUPP;
 
         mutex_lock(&econet_mutex);
 
         sk = sock->sk;
         eo = ec_sk(sk);
 
         sec->sec_family          = AF_ECONET;
         sec->port          = eo->port;
         sec->addr.station = eo->station;
         sec->addr.net          = eo->net;
 
         mutex_unlock(&econet_mutex);
 
         *uaddr_len = sizeof(*sec);
         return 0;
 }
 
 static void econet_destroy_timer(unsigned long data)
 {
         struct sock *sk=(struct sock *)data;
 
         if (!atomic_read(&sk->sk_wmem_alloc) &&
             !atomic_read(&sk->sk_rmem_alloc)) {
                 sk_free(sk);
                 return;
         }
 
         sk->sk_timer.expires = jiffies + 10 * HZ;
         add_timer(&sk->sk_timer);
         printk(KERN_DEBUG "econet socket destroy delayed\n");
 }
 
 /*
  *        Close an econet socket.
  */
 
 static int econet_release(struct socket *sock)
 {
         struct sock *sk;
 
         mutex_lock(&econet_mutex);
 
         sk = sock->sk;
         if (!sk)
                 goto out_unlock;
 
         econet_remove_socket(&econet_sklist, sk);
 
         /*
          *        Now the socket is dead. No more input will appear.
          */
 
         sk->sk_state_change(sk);        /* It is useless. Just for sanity. */
 
         sock_orphan(sk);
 
         /* Purge queues */
 
         skb_queue_purge(&sk->sk_receive_queue);
 
         if (atomic_read(&sk->sk_rmem_alloc) ||
             atomic_read(&sk->sk_wmem_alloc)) {
                 sk->sk_timer.data     = (unsigned long)sk;
                 sk->sk_timer.expires  = jiffies + HZ;
                 sk->sk_timer.function = econet_destroy_timer;
                 add_timer(&sk->sk_timer);
 
                 goto out_unlock;
         }
 
         sk_free(sk);
 
 out_unlock:
         mutex_unlock(&econet_mutex);
         return 0;
 }
 
 static struct proto econet_proto = {
         .name          = "ECONET",
         .owner          = THIS_MODULE,
         .obj_size = sizeof(struct econet_sock),
 };
 
 /*
  *        Create an Econet socket
  */
 
 static int econet_create(struct net *net, struct socket *sock, int protocol)
 {
         struct sock *sk;
         struct econet_sock *eo;
         int err;
 
         if (net != &init_net)
                 return -EAFNOSUPPORT;
 
         /* Econet only provides datagram services. */
         if (sock->type != SOCK_DGRAM)
                 return -ESOCKTNOSUPPORT;
 
         sock->state = SS_UNCONNECTED;
 
         err = -ENOBUFS;
         sk = sk_alloc(net, PF_ECONET, GFP_KERNEL, &econet_proto);
         if (sk == NULL)
                 goto out;
 
         sk->sk_reuse = 1;
         sock->ops = &econet_ops;
         sock_init_data(sock, sk);
 
         eo = ec_sk(sk);
         sock_reset_flag(sk, SOCK_ZAPPED);
         sk->sk_family = PF_ECONET;
         eo->num = protocol;
 
         econet_insert_socket(&econet_sklist, sk);
         return(0);
 out:
         return err;
 }
 
 /*
  *        Handle Econet specific ioctls
  */
 
 static int ec_dev_ioctl(struct socket *sock, unsigned int cmd, void __user *arg)
 {
         struct ifreq ifr;
         struct ec_device *edev;
         struct net_device *dev;
         struct sockaddr_ec *sec;
         int err;
 
         /*
          *        Fetch the caller's info block into kernel space
          */
 
         if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
                 return -EFAULT;
 
         if ((dev = dev_get_by_name(&init_net, ifr.ifr_name)) == NULL)
                 return -ENODEV;
 
         sec = (struct sockaddr_ec *)&ifr.ifr_addr;
 
         mutex_lock(&econet_mutex);
 
         err = 0;
         switch (cmd) {
         case SIOCSIFADDR:
                 edev = dev->ec_ptr;
                 if (edev == NULL) {
                         /* Magic up a new one. */
                         edev = kzalloc(sizeof(struct ec_device), GFP_KERNEL);
                         if (edev == NULL) {
                                 err = -ENOMEM;
                                 break;
                         }
                         dev->ec_ptr = edev;
                 } else
                         net2dev_map[edev->net] = NULL;
                 edev->station = sec->addr.station;
                 edev->net = sec->addr.net;
                 net2dev_map[sec->addr.net] = dev;
                 if (!net2dev_map[0])
                         net2dev_map[0] = dev;
                 break;
 
         case SIOCGIFADDR:
                 edev = dev->ec_ptr;
                 if (edev == NULL) {
                         err = -ENODEV;
                         break;
                 }
                 memset(sec, 0, sizeof(struct sockaddr_ec));
                 sec->addr.station = edev->station;
                 sec->addr.net = edev->net;
                 sec->sec_family = AF_ECONET;
                 dev_put(dev);
                 if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
                         err = -EFAULT;
                 break;
 
         default:
                 err = -EINVAL;
                 break;
         }
 
         mutex_unlock(&econet_mutex);
 
         dev_put(dev);
 
         return err;
 }
 
 /*
  *        Handle generic ioctls
  */
 
 static int econet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 {
         struct sock *sk = sock->sk;
         void __user *argp = (void __user *)arg;
 
         switch(cmd) {
                 case SIOCGSTAMP:
                         return sock_get_timestamp(sk, argp);
 
                 case SIOCGSTAMPNS:
                         return sock_get_timestampns(sk, argp);
 
                 case SIOCSIFADDR:
                 case SIOCGIFADDR:
                         return ec_dev_ioctl(sock, cmd, argp);
                         break;
 
                 default:
                         return -ENOIOCTLCMD;
         }
         /*NOTREACHED*/
         return 0;
 }
 
 static struct net_proto_family econet_family_ops = {
         .family =        PF_ECONET,
         .create =        econet_create,
         .owner        =        THIS_MODULE,
 };
 
 static const struct proto_ops econet_ops = {
         .family =        PF_ECONET,
         .owner =        THIS_MODULE,
         .release =        econet_release,
         .bind =                econet_bind,
         .connect =        sock_no_connect,
         .socketpair =        sock_no_socketpair,
         .accept =        sock_no_accept,
         .getname =        econet_getname,
         .poll =                datagram_poll,
         .ioctl =        econet_ioctl,
         .listen =        sock_no_listen,
         .shutdown =        sock_no_shutdown,
         .setsockopt =        sock_no_setsockopt,
         .getsockopt =        sock_no_getsockopt,
         .sendmsg =        econet_sendmsg,
         .recvmsg =        econet_recvmsg,
         .mmap =                sock_no_mmap,
         .sendpage =        sock_no_sendpage,
 };
 
 #if defined(CONFIG_ECONET_AUNUDP) || defined(CONFIG_ECONET_NATIVE)
 /*
  *        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;
         struct hlist_node *node;
 
         sk_for_each(sk, node, &econet_sklist) {
                 struct econet_sock *opt = ec_sk(sk);
                 if ((opt->port == port || opt->port == 0) &&
                     (opt->station == station || opt->station == 0) &&
                     (opt->net == net || opt->net == 0))
                         goto found;
         }
         sk = NULL;
 found:
         return sk;
 }
 
 /*
  *        Queue a received packet for a socket.
  */
 
 static int ec_queue_packet(struct sock *sk, struct sk_buff *skb,
                            unsigned char stn, unsigned char net,
                            unsigned char cb, unsigned char port)
 {
         struct ec_cb *eb = (struct ec_cb *)&skb->cb;
         struct sockaddr_ec *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 = port;
         sec->cb = cb;
         sec->addr.net = net;
         sec->addr.station = stn;
 
         return sock_queue_rcv_skb(sk, skb);
 }
 #endif
 
 #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 = {
                 .sin_family = AF_INET,
                 .sin_port = htons(AUN_PORT),
                 .sin_addr = {.s_addr = addr}
         };
         struct aunhdr ah = {.code = code, .cb = cb, .handle = seq};
         struct kvec iov = {.iov_base = (void *)&ah, .iov_len = sizeof(ah)};
         struct msghdr udpmsg;
 
         udpmsg.msg_name = (void *)&sin;
         udpmsg.msg_namelen = sizeof(sin);
         udpmsg.msg_control = NULL;
         udpmsg.msg_controllen = 0;
         udpmsg.msg_flags=0;
 
         kernel_sendmsg(udpsock, &udpmsg, &iov, 1, sizeof(ah));
 }
 
 
 /*
  *        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 iphdr *ip = ip_hdr(skb);
         unsigned char stn = ntohl(ip->saddr) & 0xff;
         struct sock *sk;
         struct sk_buff *newskb;
         struct ec_device *edev = skb->dev->ec_ptr;
 
         if (! edev)
                 goto bad;
 
         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;
         }
 
         memcpy(skb_put(newskb, len - sizeof(struct aunhdr)), (void *)(ah+1),
                len - sizeof(struct aunhdr));
 
         if (ec_queue_packet(sk, newskb, stn, edev->net, ah->cb, ah->port))
         {
                 /* 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, &aun_queue);
         spin_unlock_irqrestore(&aun_queue_lock, flags);
         kfree_skb(skb);
 }
 
 /*
  *        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_transport_header(skb) + sizeof(struct udphdr);
         ah = (struct aunhdr *)data;
         len = skb->len - sizeof(struct udphdr);
         ip = ip_hdr(skb);
 
         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 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, &aun_queue);
                         kfree_skb(skb);
                }
                skb = newskb;
        }
        spin_unlock_irqrestore(&aun_queue_lock, flags);

        mod_timer(&ab_cleanup_timer, jiffies + (HZ*2));
}

static int __init aun_udp_initialise(void)
{
        int error;
        struct sockaddr_in sin;

        skb_queue_head_init(&aun_queue);
        spin_lock_init(&aun_queue_lock);
        setup_timer(&ab_cleanup_timer, ab_cleanup, 0);
        ab_cleanup_timer.expires = jiffies + (HZ*2);
        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_kern(PF_INET, SOCK_DGRAM, 0, &udpsock)) < 0)
        {
                printk("AUN: socket error %d\n", -error);
                return error;
        }

        udpsock->sk->sk_reuse = 1;
        udpsock->sk->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->sk_data_ready = aun_data_available;

        return 0;

release:
        sock_release(udpsock);
        udpsock = NULL;
        return error;
}
#endif

#ifdef CONFIG_ECONET_NATIVE

/*
 *        Receive an Econet frame from a device.
 */

static int econet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
        struct ec_framehdr *hdr;
        struct sock *sk;
        struct ec_device *edev = dev->ec_ptr;

        if (!net_eq(dev_net(dev), &init_net))
                goto drop;

        if (skb->pkt_type == PACKET_OTHERHOST)
                goto drop;

        if (!edev)
                goto drop;

        if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
                return NET_RX_DROP;

        if (!pskb_may_pull(skb, sizeof(struct ec_framehdr)))
                goto drop;

        hdr = (struct ec_framehdr *) skb->data;

        /* First check for encapsulated IP */
        if (hdr->port == EC_PORT_IP) {
                skb->protocol = htons(ETH_P_IP);
                skb_pull(skb, sizeof(struct ec_framehdr));
                netif_rx(skb);
                return 0;
        }

        sk = ec_listening_socket(hdr->port, hdr->src_stn, hdr->src_net);
        if (!sk)
                goto drop;

        if (ec_queue_packet(sk, skb, edev->net, hdr->src_stn, hdr->cb,
                            hdr->port))
                goto drop;

        return 0;

drop:
        kfree_skb(skb);
        return NET_RX_DROP;
}

static struct packet_type econet_packet_type = {
        .type =                __constant_htons(ETH_P_ECONET),
        .func =                econet_rcv,
};

static void econet_hw_initialise(void)
{
        dev_add_pack(&econet_packet_type);
}

#endif

static int econet_notifier(struct notifier_block *this, unsigned long msg, void *data)
{
        struct net_device *dev = (struct net_device *)data;
        struct ec_device *edev;

        if (!net_eq(dev_net(dev), &init_net))
                return NOTIFY_DONE;

        switch (msg) {
        case NETDEV_UNREGISTER:
                /* A device has gone down - kill any data we hold for it. */
                edev = dev->ec_ptr;
                if (edev)
                {
                        if (net2dev_map[0] == dev)
                                net2dev_map[0] = NULL;
                        net2dev_map[edev->net] = NULL;
                        kfree(edev);
                        dev->ec_ptr = NULL;
                }
                break;
        }

        return NOTIFY_DONE;
}

static struct notifier_block econet_netdev_notifier = {
        .notifier_call =econet_notifier,
};

static void __exit econet_proto_exit(void)
{
#ifdef CONFIG_ECONET_AUNUDP
        del_timer(&ab_cleanup_timer);
        if (udpsock)
                sock_release(udpsock);
#endif
        unregister_netdevice_notifier(&econet_netdev_notifier);
#ifdef CONFIG_ECONET_NATIVE
        dev_remove_pack(&econet_packet_type);
#endif
        sock_unregister(econet_family_ops.family);
        proto_unregister(&econet_proto);
}

static int __init econet_proto_init(void)
{
        int err = proto_register(&econet_proto, 0);

        if (err != 0)
                goto out;
        sock_register(&econet_family_ops);
#ifdef CONFIG_ECONET_AUNUDP
        spin_lock_init(&aun_queue_lock);
        aun_udp_initialise();
#endif
#ifdef CONFIG_ECONET_NATIVE
        econet_hw_initialise();
#endif
        register_netdevice_notifier(&econet_netdev_notifier);
out:
        return err;
}

module_init(econet_proto_init);
module_exit(econet_proto_exit);

MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_ECONET);