text: /*
   *	Implements an IPX socket layer.
   *
   *	This code is derived from work by
   *		Ross Biro	: 	Writing the original IP stack
   *		Fred Van Kempen :	Tidying up the TCP/IP
   *
   *	Many thanks go to Keith Baker, Institute For Industrial Information
   *	Technology Ltd, Swansea University for allowing me to work on this
   *	in my own time even though it was in some ways related to commercial
   *	work I am currently employed to do there.
   *
   *	All the material in this file is subject to the Gnu license version 2.
   *	Neither Alan Cox nor the Swansea University Computer Society admit
   *	liability nor provide warranty for any of this software. This material
   *	is provided as is and at no charge.
   *
   *	Portions Copyright (c) 2000-2003 Conectiva, Inc. <acme@conectiva.com.br>
   *	Neither Arnaldo Carvalho de Melo nor Conectiva, Inc. admit liability nor
   *	provide warranty for any of this software. This material is provided
   *	"AS-IS" and at no charge.
   *
   * 	Portions Copyright (c) 1995 Caldera, Inc. <greg@caldera.com>
   *	Neither Greg Page nor Caldera, Inc. admit liability nor provide
   *	warranty for any of this software. This material is provided
   *	"AS-IS" and at no charge.
   *
   *	See net/ipx/ChangeLog.
   */
  
  #include <linux/capability.h>
  #include <linux/errno.h>
  #include <linux/if_arp.h>
  #include <linux/if_ether.h>
  #include <linux/init.h>
  #include <linux/ipx.h>
  #include <linux/kernel.h>
  #include <linux/list.h>
  #include <linux/module.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>
  #include <linux/uio.h>
  #include <linux/skbuff.h>
  #include <linux/smp_lock.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/string.h>
  #include <linux/types.h>
  #include <linux/termios.h>
  
  #include <net/ipx.h>
  #include <net/p8022.h>
  #include <net/psnap.h>
  #include <net/sock.h>
  #include <net/tcp_states.h>
  
  #include <asm/uaccess.h>
  
  #ifdef CONFIG_SYSCTL
  extern void ipx_register_sysctl(void);
  extern void ipx_unregister_sysctl(void);
  #else
  #define ipx_register_sysctl()
  #define ipx_unregister_sysctl()
  #endif
  
  /* Configuration Variables */
  static unsigned char ipxcfg_max_hops = 16;
  static char ipxcfg_auto_select_primary;
  static char ipxcfg_auto_create_interfaces;
  int sysctl_ipx_pprop_broadcasting = 1;
  
  /* Global Variables */
  static struct datalink_proto *p8022_datalink;
  static struct datalink_proto *pEII_datalink;
  static struct datalink_proto *p8023_datalink;
  static struct datalink_proto *pSNAP_datalink;
  
  static const struct proto_ops ipx_dgram_ops;
  
  LIST_HEAD(ipx_interfaces);
  DEFINE_SPINLOCK(ipx_interfaces_lock);
  
  struct ipx_interface *ipx_primary_net;
  struct ipx_interface *ipx_internal_net;
  
  extern int ipxrtr_add_route(__be32 network, struct ipx_interface *intrfc,
  			    unsigned char *node);
  extern void ipxrtr_del_routes(struct ipx_interface *intrfc);
  extern int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
  			       struct iovec *iov, size_t len, int noblock);
  extern int ipxrtr_route_skb(struct sk_buff *skb);
  extern struct ipx_route *ipxrtr_lookup(__be32 net);
  extern int ipxrtr_ioctl(unsigned int cmd, void __user *arg);
  
  struct ipx_interface *ipx_interfaces_head(void)
  {
  	struct ipx_interface *rc = NULL;
  
  	if (!list_empty(&ipx_interfaces))
  		rc = list_entry(ipx_interfaces.next,
  				struct ipx_interface, node);
  	return rc;
  }
  
  static void ipxcfg_set_auto_select(char val)
  {
  	ipxcfg_auto_select_primary = val;
  	if (val && !ipx_primary_net)
  		ipx_primary_net = ipx_interfaces_head();
  }
  
  static int ipxcfg_get_config_data(struct ipx_config_data __user *arg)
  {
  	struct ipx_config_data vals;
  
  	vals.ipxcfg_auto_create_interfaces = ipxcfg_auto_create_interfaces;
  	vals.ipxcfg_auto_select_primary	   = ipxcfg_auto_select_primary;
  
  	return copy_to_user(arg, &vals, sizeof(vals)) ? -EFAULT : 0;
  }
  
  /*
   * Note: Sockets may not be removed _during_ an interrupt or inet_bh
   * handler using this technique. They can be added although we do not
   * use this facility.
   */
  
  static void ipx_remove_socket(struct sock *sk)
  {
  	/* Determine interface with which socket is associated */
  	struct ipx_interface *intrfc = ipx_sk(sk)->intrfc;
  
  	if (!intrfc)
  		goto out;
  
  	ipxitf_hold(intrfc);
  	spin_lock_bh(&intrfc->if_sklist_lock);
  	sk_del_node_init(sk);
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  	ipxitf_put(intrfc);
  out:
  	return;
  }
  
  static void ipx_destroy_socket(struct sock *sk)
  {
  	ipx_remove_socket(sk);
  	skb_queue_purge(&sk->sk_receive_queue);
  	sk_refcnt_debug_dec(sk);
  	sock_put(sk);
  }
  
  /*
   * The following code is used to support IPX Interfaces (IPXITF).  An
   * IPX interface is defined by a physical device and a frame type.
   */
  
  /* ipxitf_clear_primary_net has to be called with ipx_interfaces_lock held */
  
  static void ipxitf_clear_primary_net(void)
  {
  	ipx_primary_net = NULL;
  	if (ipxcfg_auto_select_primary)
  		ipx_primary_net = ipx_interfaces_head();
  }
  
  static struct ipx_interface *__ipxitf_find_using_phys(struct net_device *dev,
  						      __be16 datalink)
  {
  	struct ipx_interface *i;
  
  	list_for_each_entry(i, &ipx_interfaces, node)
  		if (i->if_dev == dev && i->if_dlink_type == datalink)
  			goto out;
  	i = NULL;
  out:
  	return i;
  }
  
  static struct ipx_interface *ipxitf_find_using_phys(struct net_device *dev,
  						    __be16 datalink)
  {
  	struct ipx_interface *i;
  
  	spin_lock_bh(&ipx_interfaces_lock);
  	i = __ipxitf_find_using_phys(dev, datalink);
  	if (i)
  		ipxitf_hold(i);
  	spin_unlock_bh(&ipx_interfaces_lock);
  	return i;
  }
  
  struct ipx_interface *ipxitf_find_using_net(__be32 net)
  {
  	struct ipx_interface *i;
  
  	spin_lock_bh(&ipx_interfaces_lock);
  	if (net) {
  		list_for_each_entry(i, &ipx_interfaces, node)
  			if (i->if_netnum == net)
  				goto hold;
  		i = NULL;
  		goto unlock;
  	}
  
  	i = ipx_primary_net;
  	if (i)
  hold:
  		ipxitf_hold(i);
  unlock:
  	spin_unlock_bh(&ipx_interfaces_lock);
  	return i;
  }
  
  /* Sockets are bound to a particular IPX interface. */
  static void ipxitf_insert_socket(struct ipx_interface *intrfc, struct sock *sk)
  {
  	ipxitf_hold(intrfc);
  	spin_lock_bh(&intrfc->if_sklist_lock);
  	ipx_sk(sk)->intrfc = intrfc;
  	sk_add_node(sk, &intrfc->if_sklist);
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  	ipxitf_put(intrfc);
  }
  
  /* caller must hold intrfc->if_sklist_lock */
  static struct sock *__ipxitf_find_socket(struct ipx_interface *intrfc,
  					 __be16 port)
  {
  	struct sock *s;
  	struct hlist_node *node;
  
  	sk_for_each(s, node, &intrfc->if_sklist)
  		if (ipx_sk(s)->port == port)
  			goto found;
  	s = NULL;
  found:
  	return s;
  }
  
  /* caller must hold a reference to intrfc */
  static struct sock *ipxitf_find_socket(struct ipx_interface *intrfc,
  					__be16 port)
  {
  	struct sock *s;
  
  	spin_lock_bh(&intrfc->if_sklist_lock);
  	s = __ipxitf_find_socket(intrfc, port);
  	if (s)
  		sock_hold(s);
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  
  	return s;
  }
  
  #ifdef CONFIG_IPX_INTERN
  static struct sock *ipxitf_find_internal_socket(struct ipx_interface *intrfc,
  						unsigned char *ipx_node,
  						__be16 port)
  {
  	struct sock *s;
  	struct hlist_node *node;
  
  	ipxitf_hold(intrfc);
  	spin_lock_bh(&intrfc->if_sklist_lock);
  
  	sk_for_each(s, node, &intrfc->if_sklist) {
  		struct ipx_sock *ipxs = ipx_sk(s);
  
  		if (ipxs->port == port &&
  		    !memcmp(ipx_node, ipxs->node, IPX_NODE_LEN))
  			goto found;
  	}
  	s = NULL;
  found:
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  	ipxitf_put(intrfc);
  	return s;
  }
  #endif
  
  static void __ipxitf_down(struct ipx_interface *intrfc)
  {
  	struct sock *s;
  	struct hlist_node *node, *t;
  
  	/* Delete all routes associated with this interface */
  	ipxrtr_del_routes(intrfc);
  
  	spin_lock_bh(&intrfc->if_sklist_lock);
  	/* error sockets */
  	sk_for_each_safe(s, node, t, &intrfc->if_sklist) {
  		struct ipx_sock *ipxs = ipx_sk(s);
  
  		s->sk_err = ENOLINK;
  		s->sk_error_report(s);
  		ipxs->intrfc = NULL;
  		ipxs->port   = 0;
  		sock_set_flag(s, SOCK_ZAPPED); /* Indicates it is no longer bound */
  		sk_del_node_init(s);
  	}
  	INIT_HLIST_HEAD(&intrfc->if_sklist);
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  
  	/* remove this interface from list */
  	list_del(&intrfc->node);
  
  	/* remove this interface from *special* networks */
  	if (intrfc == ipx_primary_net)
  		ipxitf_clear_primary_net();
  	if (intrfc == ipx_internal_net)
  		ipx_internal_net = NULL;
  
  	if (intrfc->if_dev)
  		dev_put(intrfc->if_dev);
  	kfree(intrfc);
  }
  
  void ipxitf_down(struct ipx_interface *intrfc)
  {
  	spin_lock_bh(&ipx_interfaces_lock);
  	__ipxitf_down(intrfc);
  	spin_unlock_bh(&ipx_interfaces_lock);
  }
  
  static __inline__ void __ipxitf_put(struct ipx_interface *intrfc)
  {
  	if (atomic_dec_and_test(&intrfc->refcnt))
  		__ipxitf_down(intrfc);
  }
  
  static int ipxitf_device_event(struct notifier_block *notifier,
  				unsigned long event, void *ptr)
  {
  	struct net_device *dev = ptr;
  	struct ipx_interface *i, *tmp;
  
  	if (!net_eq(dev_net(dev), &init_net))
  		return NOTIFY_DONE;
  
  	if (event != NETDEV_DOWN && event != NETDEV_UP)
  		goto out;
  
  	spin_lock_bh(&ipx_interfaces_lock);
  	list_for_each_entry_safe(i, tmp, &ipx_interfaces, node)
  		if (i->if_dev == dev) {
  			if (event == NETDEV_UP)
  				ipxitf_hold(i);
  			else
  				__ipxitf_put(i);
  		}
  	spin_unlock_bh(&ipx_interfaces_lock);
  out:
  	return NOTIFY_DONE;
  }
  
  
  static __exit void ipxitf_cleanup(void)
  {
  	struct ipx_interface *i, *tmp;
  
  	spin_lock_bh(&ipx_interfaces_lock);
  	list_for_each_entry_safe(i, tmp, &ipx_interfaces, node)
  		__ipxitf_put(i);
  	spin_unlock_bh(&ipx_interfaces_lock);
  }
  
  static void ipxitf_def_skb_handler(struct sock *sock, struct sk_buff *skb)
  {
  	if (sock_queue_rcv_skb(sock, skb) < 0)
  		kfree_skb(skb);
  }
  
  /*
   * On input skb->sk is NULL. Nobody is charged for the memory.
   */
  
  /* caller must hold a reference to intrfc */
  
  #ifdef CONFIG_IPX_INTERN
  static int ipxitf_demux_socket(struct ipx_interface *intrfc,
  			       struct sk_buff *skb, int copy)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	int is_broadcast = !memcmp(ipx->ipx_dest.node, ipx_broadcast_node,
  				   IPX_NODE_LEN);
  	struct sock *s;
  	struct hlist_node *node;
  	int rc;
  
  	spin_lock_bh(&intrfc->if_sklist_lock);
  
  	sk_for_each(s, node, &intrfc->if_sklist) {
  		struct ipx_sock *ipxs = ipx_sk(s);
  
  		if (ipxs->port == ipx->ipx_dest.sock &&
  		    (is_broadcast || !memcmp(ipx->ipx_dest.node,
  					     ipxs->node, IPX_NODE_LEN))) {
  			/* We found a socket to which to send */
  			struct sk_buff *skb1;
  
  			if (copy) {
  				skb1 = skb_clone(skb, GFP_ATOMIC);
  				rc = -ENOMEM;
  				if (!skb1)
  					goto out;
  			} else {
  				skb1 = skb;
  				copy = 1; /* skb may only be used once */
  			}
  			ipxitf_def_skb_handler(s, skb1);
  
  			/* On an external interface, one socket can listen */
  			if (intrfc != ipx_internal_net)
  				break;
  		}
  	}
  
  	/* skb was solely for us, and we did not make a copy, so free it. */
  	if (!copy)
  		kfree_skb(skb);
  
  	rc = 0;
  out:
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  	return rc;
  }
  #else
  static struct sock *ncp_connection_hack(struct ipx_interface *intrfc,
  					struct ipxhdr *ipx)
  {
  	/* The packet's target is a NCP connection handler. We want to hand it
  	 * to the correct socket directly within the kernel, so that the
  	 * mars_nwe packet distribution process does not have to do it. Here we
  	 * only care about NCP and BURST packets.
  	 *
  	 * You might call this a hack, but believe me, you do not want a
  	 * complete NCP layer in the kernel, and this is VERY fast as well. */
  	struct sock *sk = NULL;
  	int connection = 0;
  	u8 *ncphdr = (u8 *)(ipx + 1);
  
  	if (*ncphdr == 0x22 && *(ncphdr + 1) == 0x22) /* NCP request */
  		connection = (((int) *(ncphdr + 5)) << 8) | (int) *(ncphdr + 3);
  	else if (*ncphdr == 0x77 && *(ncphdr + 1) == 0x77) /* BURST packet */
  		connection = (((int) *(ncphdr + 9)) << 8) | (int) *(ncphdr + 8);
  
  	if (connection) {
  		struct hlist_node *node;
  		/* Now we have to look for a special NCP connection handling
  		 * socket. Only these sockets have ipx_ncp_conn != 0, set by
  		 * SIOCIPXNCPCONN. */
  		spin_lock_bh(&intrfc->if_sklist_lock);
  		sk_for_each(sk, node, &intrfc->if_sklist)
  			if (ipx_sk(sk)->ipx_ncp_conn == connection) {
  				sock_hold(sk);
  				goto found;
  			}
  		sk = NULL;
  	found:
  		spin_unlock_bh(&intrfc->if_sklist_lock);
  	}
  	return sk;
  }
  
  static int ipxitf_demux_socket(struct ipx_interface *intrfc,
  			       struct sk_buff *skb, int copy)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	struct sock *sock1 = NULL, *sock2 = NULL;
  	struct sk_buff *skb1 = NULL, *skb2 = NULL;
  	int rc;
  
  	if (intrfc == ipx_primary_net && ntohs(ipx->ipx_dest.sock) == 0x451)
  		sock1 = ncp_connection_hack(intrfc, ipx);
  	if (!sock1)
  		/* No special socket found, forward the packet the normal way */
  		sock1 = ipxitf_find_socket(intrfc, ipx->ipx_dest.sock);
  
  	/*
  	 * We need to check if there is a primary net and if
  	 * this is addressed to one of the *SPECIAL* sockets because
  	 * these need to be propagated to the primary net.
  	 * The *SPECIAL* socket list contains: 0x452(SAP), 0x453(RIP) and
  	 * 0x456(Diagnostic).
  	 */
  
  	if (ipx_primary_net && intrfc != ipx_primary_net) {
  		const int dsock = ntohs(ipx->ipx_dest.sock);
  
  		if (dsock == 0x452 || dsock == 0x453 || dsock == 0x456)
  			/* The appropriate thing to do here is to dup the
  			 * packet and route to the primary net interface via
  			 * ipxitf_send; however, we'll cheat and just demux it
  			 * here. */
  			sock2 = ipxitf_find_socket(ipx_primary_net,
  							ipx->ipx_dest.sock);
  	}
  
  	/*
  	 * If there is nothing to do return. The kfree will cancel any charging.
  	 */
  	rc = 0;
  	if (!sock1 && !sock2) {
  		if (!copy)
  			kfree_skb(skb);
  		goto out;
  	}
  
  	/*
  	 * This next segment of code is a little awkward, but it sets it up
  	 * so that the appropriate number of copies of the SKB are made and
  	 * that skb1 and skb2 point to it (them) so that it (they) can be
  	 * demuxed to sock1 and/or sock2.  If we are unable to make enough
  	 * copies, we do as much as is possible.
  	 */
  
  	if (copy)
  		skb1 = skb_clone(skb, GFP_ATOMIC);
  	else
  		skb1 = skb;
  
  	rc = -ENOMEM;
  	if (!skb1)
  		goto out_put;
  
  	/* Do we need 2 SKBs? */
  	if (sock1 && sock2)
  		skb2 = skb_clone(skb1, GFP_ATOMIC);
  	else
  		skb2 = skb1;
  
  	if (sock1)
  		ipxitf_def_skb_handler(sock1, skb1);
  
  	if (!skb2)
  		goto out_put;
  
  	if (sock2)
  		ipxitf_def_skb_handler(sock2, skb2);
  
  	rc = 0;
  out_put:
  	if (sock1)
  		sock_put(sock1);
  	if (sock2)
  		sock_put(sock2);
  out:
  	return rc;
  }
  #endif	/* CONFIG_IPX_INTERN */
  
  static struct sk_buff *ipxitf_adjust_skbuff(struct ipx_interface *intrfc,
  					    struct sk_buff *skb)
  {
  	struct sk_buff *skb2;
  	int in_offset = (unsigned char *)ipx_hdr(skb) - skb->head;
  	int out_offset = intrfc->if_ipx_offset;
  	int len;
  
  	/* Hopefully, most cases */
  	if (in_offset >= out_offset)
  		return skb;
  
  	/* Need new SKB */
  	len  = skb->len + out_offset;
  	skb2 = alloc_skb(len, GFP_ATOMIC);
  	if (skb2) {
  		skb_reserve(skb2, out_offset);
  		skb_reset_network_header(skb2);
  		skb_reset_transport_header(skb2);
  		skb_put(skb2, skb->len);
  		memcpy(ipx_hdr(skb2), ipx_hdr(skb), skb->len);
  		memcpy(skb2->cb, skb->cb, sizeof(skb->cb));
  	}
  	kfree_skb(skb);
  	return skb2;
  }
  
  /* caller must hold a reference to intrfc and the skb has to be unshared */
  int ipxitf_send(struct ipx_interface *intrfc, struct sk_buff *skb, char *node)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	struct net_device *dev = intrfc->if_dev;
  	struct datalink_proto *dl = intrfc->if_dlink;
  	char dest_node[IPX_NODE_LEN];
  	int send_to_wire = 1;
  	int addr_len;
  
  	ipx->ipx_tctrl = IPX_SKB_CB(skb)->ipx_tctrl;
  	ipx->ipx_dest.net = IPX_SKB_CB(skb)->ipx_dest_net;
  	ipx->ipx_source.net = IPX_SKB_CB(skb)->ipx_source_net;
  
  	/* see if we need to include the netnum in the route list */
  	if (IPX_SKB_CB(skb)->last_hop.index >= 0) {
  		__be32 *last_hop = (__be32 *)(((u8 *) skb->data) +
  				sizeof(struct ipxhdr) +
  				IPX_SKB_CB(skb)->last_hop.index *
  				sizeof(__be32));
  		*last_hop = IPX_SKB_CB(skb)->last_hop.netnum;
  		IPX_SKB_CB(skb)->last_hop.index = -1;
  	}
  
  	/*
  	 * We need to know how many skbuffs it will take to send out this
  	 * packet to avoid unnecessary copies.
  	 */
  
  	if (!dl || !dev || dev->flags & IFF_LOOPBACK)
  		send_to_wire = 0;	/* No non looped */
  
  	/*
  	 * See if this should be demuxed to sockets on this interface
  	 *
  	 * We want to ensure the original was eaten or that we only use
  	 * up clones.
  	 */
  
  	if (ipx->ipx_dest.net == intrfc->if_netnum) {
  		/*
  		 * To our own node, loop and free the original.
  		 * The internal net will receive on all node address.
  		 */
  		if (intrfc == ipx_internal_net ||
  		    !memcmp(intrfc->if_node, node, IPX_NODE_LEN)) {
  			/* Don't charge sender */
  			skb_orphan(skb);
  
  			/* Will charge receiver */
  			return ipxitf_demux_socket(intrfc, skb, 0);
  		}
  
  		/* Broadcast, loop and possibly keep to send on. */
  		if (!memcmp(ipx_broadcast_node, node, IPX_NODE_LEN)) {
  			if (!send_to_wire)
  				skb_orphan(skb);
  			ipxitf_demux_socket(intrfc, skb, send_to_wire);
  			if (!send_to_wire)
  				goto out;
  		}
  	}
  
  	/*
  	 * If the originating net is not equal to our net; this is routed
  	 * We are still charging the sender. Which is right - the driver
  	 * free will handle this fairly.
  	 */
  	if (ipx->ipx_source.net != intrfc->if_netnum) {
  		/*
  		 * Unshare the buffer before modifying the count in
  		 * case it's a flood or tcpdump
  		 */
  		skb = skb_unshare(skb, GFP_ATOMIC);
  		if (!skb)
  			goto out;
  		if (++ipx->ipx_tctrl > ipxcfg_max_hops)
  			send_to_wire = 0;
  	}
  
  	if (!send_to_wire) {
  		kfree_skb(skb);
  		goto out;
  	}
  
  	/* Determine the appropriate hardware address */
  	addr_len = dev->addr_len;
  	if (!memcmp(ipx_broadcast_node, node, IPX_NODE_LEN))
  		memcpy(dest_node, dev->broadcast, addr_len);
  	else
  		memcpy(dest_node, &(node[IPX_NODE_LEN-addr_len]), addr_len);
  
  	/* Make any compensation for differing physical/data link size */
  	skb = ipxitf_adjust_skbuff(intrfc, skb);
  	if (!skb)
  		goto out;
  
  	/* set up data link and physical headers */
  	skb->dev	= dev;
  	skb->protocol	= htons(ETH_P_IPX);
  
  	/* Send it out */
  	dl->request(dl, skb, dest_node);
  out:
  	return 0;
  }
  
  static int ipxitf_add_local_route(struct ipx_interface *intrfc)
  {
  	return ipxrtr_add_route(intrfc->if_netnum, intrfc, NULL);
  }
  
  static void ipxitf_discover_netnum(struct ipx_interface *intrfc,
  				   struct sk_buff *skb);
  static int ipxitf_pprop(struct ipx_interface *intrfc, struct sk_buff *skb);
  
  static int ipxitf_rcv(struct ipx_interface *intrfc, struct sk_buff *skb)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	int rc = 0;
  
  	ipxitf_hold(intrfc);
  
  	/* See if we should update our network number */
  	if (!intrfc->if_netnum) /* net number of intrfc not known yet */
  		ipxitf_discover_netnum(intrfc, skb);
  
  	IPX_SKB_CB(skb)->last_hop.index = -1;
  	if (ipx->ipx_type == IPX_TYPE_PPROP) {
  		rc = ipxitf_pprop(intrfc, skb);
  		if (rc)
  			goto out_free_skb;
  	}
  
  	/* local processing follows */
  	if (!IPX_SKB_CB(skb)->ipx_dest_net)
  		IPX_SKB_CB(skb)->ipx_dest_net = intrfc->if_netnum;
  	if (!IPX_SKB_CB(skb)->ipx_source_net)
  		IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;
  
  	/* it doesn't make sense to route a pprop packet, there's no meaning
  	 * in the ipx_dest_net for such packets */
  	if (ipx->ipx_type != IPX_TYPE_PPROP &&
  	    intrfc->if_netnum != IPX_SKB_CB(skb)->ipx_dest_net) {
  		/* We only route point-to-point packets. */
  		if (skb->pkt_type == PACKET_HOST) {
  			skb = skb_unshare(skb, GFP_ATOMIC);
  			if (skb)
  				rc = ipxrtr_route_skb(skb);
  			goto out_intrfc;
  		}
  
  		goto out_free_skb;
  	}
  
  	/* see if we should keep it */
  	if (!memcmp(ipx_broadcast_node, ipx->ipx_dest.node, IPX_NODE_LEN) ||
  	    !memcmp(intrfc->if_node, ipx->ipx_dest.node, IPX_NODE_LEN)) {
  		rc = ipxitf_demux_socket(intrfc, skb, 0);
  		goto out_intrfc;
  	}
  
  	/* we couldn't pawn it off so unload it */
  out_free_skb:
  	kfree_skb(skb);
  out_intrfc:
  	ipxitf_put(intrfc);
  	return rc;
  }
  
  static void ipxitf_discover_netnum(struct ipx_interface *intrfc,
  				   struct sk_buff *skb)
  {
  	const struct ipx_cb *cb = IPX_SKB_CB(skb);
  
  	/* see if this is an intra packet: source_net == dest_net */
  	if (cb->ipx_source_net == cb->ipx_dest_net && cb->ipx_source_net) {
  		struct ipx_interface *i =
  				ipxitf_find_using_net(cb->ipx_source_net);
  		/* NB: NetWare servers lie about their hop count so we
  		 * dropped the test based on it. This is the best way
  		 * to determine this is a 0 hop count packet. */
  		if (!i) {
  			intrfc->if_netnum = cb->ipx_source_net;
  			ipxitf_add_local_route(intrfc);
  		} else {
  			printk(KERN_WARNING "IPX: Network number collision "
  				"%lx\n        %s %s and %s %s\n",
  				(unsigned long) ntohl(cb->ipx_source_net),
  				ipx_device_name(i),
  				ipx_frame_name(i->if_dlink_type),
  				ipx_device_name(intrfc),
  				ipx_frame_name(intrfc->if_dlink_type));
  			ipxitf_put(i);
  		}
  	}
  }
  
  /**
   * ipxitf_pprop - Process packet propagation IPX packet type 0x14, used for
   * 		  NetBIOS broadcasts
   * @intrfc: IPX interface receiving this packet
   * @skb: Received packet
   *
   * Checks if packet is valid: if its more than %IPX_MAX_PPROP_HOPS hops or if it
   * is smaller than a IPX header + the room for %IPX_MAX_PPROP_HOPS hops we drop
   * it, not even processing it locally, if it has exact %IPX_MAX_PPROP_HOPS we
   * don't broadcast it, but process it locally. See chapter 5 of Novell's "IPX
   * RIP and SAP Router Specification", Part Number 107-000029-001.
   *
   * If it is valid, check if we have pprop broadcasting enabled by the user,
   * if not, just return zero for local processing.
   *
   * If it is enabled check the packet and don't broadcast it if we have already
   * seen this packet.
   *
   * Broadcast: send it to the interfaces that aren't on the packet visited nets
   * array, just after the IPX header.
   *
   * Returns -EINVAL for invalid packets, so that the calling function drops
   * the packet without local processing. 0 if packet is to be locally processed.
   */
  static int ipxitf_pprop(struct ipx_interface *intrfc, struct sk_buff *skb)
  {
  	struct ipxhdr *ipx = ipx_hdr(skb);
  	int i, rc = -EINVAL;
  	struct ipx_interface *ifcs;
  	char *c;
  	__be32 *l;
  
  	/* Illegal packet - too many hops or too short */
  	/* We decide to throw it away: no broadcasting, no local processing.
  	 * NetBIOS unaware implementations route them as normal packets -
  	 * tctrl <= 15, any data payload... */
  	if (IPX_SKB_CB(skb)->ipx_tctrl > IPX_MAX_PPROP_HOPS ||
  	    ntohs(ipx->ipx_pktsize) < sizeof(struct ipxhdr) +
  					IPX_MAX_PPROP_HOPS * sizeof(u32))
  		goto out;
  	/* are we broadcasting this damn thing? */
  	rc = 0;
  	if (!sysctl_ipx_pprop_broadcasting)
  		goto out;
  	/* We do broadcast packet on the IPX_MAX_PPROP_HOPS hop, but we
  	 * process it locally. All previous hops broadcasted it, and process it
  	 * locally. */
  	if (IPX_SKB_CB(skb)->ipx_tctrl == IPX_MAX_PPROP_HOPS)
  		goto out;
  
  	c = ((u8 *) ipx) + sizeof(struct ipxhdr);
  	l = (__be32 *) c;
  
  	/* Don't broadcast packet if already seen this net */
  	for (i = 0; i < IPX_SKB_CB(skb)->ipx_tctrl; i++)
  		if (*l++ == intrfc->if_netnum)
  			goto out;
  
  	/* < IPX_MAX_PPROP_HOPS hops && input interface not in list. Save the
  	 * position where we will insert recvd netnum into list, later on,
  	 * in ipxitf_send */
  	IPX_SKB_CB(skb)->last_hop.index = i;
  	IPX_SKB_CB(skb)->last_hop.netnum = intrfc->if_netnum;
  	/* xmit on all other interfaces... */
  	spin_lock_bh(&ipx_interfaces_lock);
  	list_for_each_entry(ifcs, &ipx_interfaces, node) {
  		/* Except unconfigured interfaces */
  		if (!ifcs->if_netnum)
  			continue;
  
  		/* That aren't in the list */
  		if (ifcs == intrfc)
  			continue;
  		l = (__be32 *) c;
  		/* don't consider the last entry in the packet list,
  		 * it is our netnum, and it is not there yet */
  		for (i = 0; i < IPX_SKB_CB(skb)->ipx_tctrl; i++)
  			if (ifcs->if_netnum == *l++)
  				break;
  		if (i == IPX_SKB_CB(skb)->ipx_tctrl) {
  			struct sk_buff *s = skb_copy(skb, GFP_ATOMIC);
  
  			if (s) {
  				IPX_SKB_CB(s)->ipx_dest_net = ifcs->if_netnum;
  				ipxrtr_route_skb(s);
  			}
  		}
  	}
  	spin_unlock_bh(&ipx_interfaces_lock);
  out:
  	return rc;
  }
  
  static void ipxitf_insert(struct ipx_interface *intrfc)
  {
  	spin_lock_bh(&ipx_interfaces_lock);
  	list_add_tail(&intrfc->node, &ipx_interfaces);
  	spin_unlock_bh(&ipx_interfaces_lock);
  
  	if (ipxcfg_auto_select_primary && !ipx_primary_net)
  		ipx_primary_net = intrfc;
  }
  
  static struct ipx_interface *ipxitf_alloc(struct net_device *dev, __be32 netnum,
  					  __be16 dlink_type,
  					  struct datalink_proto *dlink,
  					  unsigned char internal,
  					  int ipx_offset)
  {
  	struct ipx_interface *intrfc = kmalloc(sizeof(*intrfc), GFP_ATOMIC);
  
  	if (intrfc) {
  		intrfc->if_dev		= dev;
  		intrfc->if_netnum	= netnum;
  		intrfc->if_dlink_type 	= dlink_type;
  		intrfc->if_dlink 	= dlink;
  		intrfc->if_internal 	= internal;
  		intrfc->if_ipx_offset 	= ipx_offset;
  		intrfc->if_sknum 	= IPX_MIN_EPHEMERAL_SOCKET;
  		INIT_HLIST_HEAD(&intrfc->if_sklist);
  		atomic_set(&intrfc->refcnt, 1);
  		spin_lock_init(&intrfc->if_sklist_lock);
  	}
  
  	return intrfc;
  }
  
  static int ipxitf_create_internal(struct ipx_interface_definition *idef)
  {
  	struct ipx_interface *intrfc;
  	int rc = -EEXIST;
  
  	/* Only one primary network allowed */
  	if (ipx_primary_net)
  		goto out;
  
  	/* Must have a valid network number */
  	rc = -EADDRNOTAVAIL;
  	if (!idef->ipx_network)
  		goto out;
  	intrfc = ipxitf_find_using_net(idef->ipx_network);
  	rc = -EADDRINUSE;
  	if (intrfc) {
  		ipxitf_put(intrfc);
  		goto out;
  	}
  	intrfc = ipxitf_alloc(NULL, idef->ipx_network, 0, NULL, 1, 0);
  	rc = -EAGAIN;
  	if (!intrfc)
  		goto out;
  	memcpy((char *)&(intrfc->if_node), idef->ipx_node, IPX_NODE_LEN);
  	ipx_internal_net = ipx_primary_net = intrfc;
  	ipxitf_hold(intrfc);
  	ipxitf_insert(intrfc);
  
  	rc = ipxitf_add_local_route(intrfc);
  	ipxitf_put(intrfc);
  out:
  	return rc;
  }
  
  static __be16 ipx_map_frame_type(unsigned char type)
  {
  	__be16 rc = 0;
  
  	switch (type) {
  	case IPX_FRAME_ETHERII:	rc = htons(ETH_P_IPX);		break;
  	case IPX_FRAME_8022:	rc = htons(ETH_P_802_2);	break;
  	case IPX_FRAME_SNAP:	rc = htons(ETH_P_SNAP);		break;
  	case IPX_FRAME_8023:	rc = htons(ETH_P_802_3);	break;
  	}
  
  	return rc;
  }
  
  static int ipxitf_create(struct ipx_interface_definition *idef)
  {
  	struct net_device *dev;
  	__be16 dlink_type = 0;
  	struct datalink_proto *datalink = NULL;
  	struct ipx_interface *intrfc;
  	int rc;
  
  	if (idef->ipx_special == IPX_INTERNAL) {
  		rc = ipxitf_create_internal(idef);
  		goto out;
  	}
  
  	rc = -EEXIST;
  	if (idef->ipx_special == IPX_PRIMARY && ipx_primary_net)
  		goto out;
  
  	intrfc = ipxitf_find_using_net(idef->ipx_network);
  	rc = -EADDRINUSE;
  	if (idef->ipx_network && intrfc) {
  		ipxitf_put(intrfc);
  		goto out;
  	}
  
  	if (intrfc)
  		ipxitf_put(intrfc);
  
  	dev = dev_get_by_name(&init_net, idef->ipx_device);
  	rc = -ENODEV;
  	if (!dev)
  		goto out;
  
  	switch (idef->ipx_dlink_type) {
  	case IPX_FRAME_TR_8022:
  		printk(KERN_WARNING "IPX frame type 802.2TR is "
  			"obsolete Use 802.2 instead.\n");
  		/* fall through */
  	case IPX_FRAME_8022:
  		dlink_type 	= htons(ETH_P_802_2);
  		datalink 	= p8022_datalink;
  		break;
  	case IPX_FRAME_ETHERII:
  		if (dev->type != ARPHRD_IEEE802) {
  			dlink_type 	= htons(ETH_P_IPX);
  			datalink 	= pEII_datalink;
  			break;
  		} else
  			printk(KERN_WARNING "IPX frame type EtherII over "
  					"token-ring is obsolete. Use SNAP "
  					"instead.\n");
  		/* fall through */
  	case IPX_FRAME_SNAP:
  		dlink_type 	= htons(ETH_P_SNAP);
  		datalink 	= pSNAP_datalink;
  		break;
  	case IPX_FRAME_8023:
  		dlink_type 	= htons(ETH_P_802_3);
  		datalink 	= p8023_datalink;
  		break;
  	case IPX_FRAME_NONE:
  	default:
  		rc = -EPROTONOSUPPORT;
  		goto out_dev;
  	}
  
  	rc = -ENETDOWN;
  	if (!(dev->flags & IFF_UP))
  		goto out_dev;
  
  	/* Check addresses are suitable */
  	rc = -EINVAL;
  	if (dev->addr_len > IPX_NODE_LEN)
  		goto out_dev;
  
  	intrfc = ipxitf_find_using_phys(dev, dlink_type);
  	if (!intrfc) {
  		/* Ok now create */
  		intrfc = ipxitf_alloc(dev, idef->ipx_network, dlink_type,
  				      datalink, 0, dev->hard_header_len +
  					datalink->header_length);
  		rc = -EAGAIN;
  		if (!intrfc)
  			goto out_dev;
  		/* Setup primary if necessary */
  		if (idef->ipx_special == IPX_PRIMARY)
  			ipx_primary_net = intrfc;
  		if (!memcmp(idef->ipx_node, "\000\000\000\000\000\000",
  			    IPX_NODE_LEN)) {
  			memset(intrfc->if_node, 0, IPX_NODE_LEN);
  			memcpy(intrfc->if_node + IPX_NODE_LEN - dev->addr_len,
  				dev->dev_addr, dev->addr_len);
  		} else
  			memcpy(intrfc->if_node, idef->ipx_node, IPX_NODE_LEN);
  		ipxitf_hold(intrfc);
  		ipxitf_insert(intrfc);
  	}
  
  
  	/* If the network number is known, add a route */
  	rc = 0;
  	if (!intrfc->if_netnum)
  		goto out_intrfc;
  
  	rc = ipxitf_add_local_route(intrfc);
  out_intrfc:
  	ipxitf_put(intrfc);
  	goto out;
  out_dev:
  	dev_put(dev);
  out:
  	return rc;
  }
  
  static int ipxitf_delete(struct ipx_interface_definition *idef)
  {
  	struct net_device *dev = NULL;
  	__be16 dlink_type = 0;
  	struct ipx_interface *intrfc;
  	int rc = 0;
  
  	spin_lock_bh(&ipx_interfaces_lock);
  	if (idef->ipx_special == IPX_INTERNAL) {
  		if (ipx_internal_net) {
  			__ipxitf_put(ipx_internal_net);
  			goto out;
  		}
  		rc = -ENOENT;
  		goto out;
  	}
  
  	dlink_type = ipx_map_frame_type(idef->ipx_dlink_type);
  	rc = -EPROTONOSUPPORT;
  	if (!dlink_type)
  		goto out;
  
  	dev = __dev_get_by_name(&init_net, idef->ipx_device);
  	rc = -ENODEV;
  	if (!dev)
  		goto out;
  
  	intrfc = __ipxitf_find_using_phys(dev, dlink_type);
  	rc = -EINVAL;
  	if (!intrfc)
  		goto out;
  	__ipxitf_put(intrfc);
  
  	rc = 0;
  out:
  	spin_unlock_bh(&ipx_interfaces_lock);
  	return rc;
  }
  
  static struct ipx_interface *ipxitf_auto_create(struct net_device *dev,
  						__be16 dlink_type)
  {
  	struct ipx_interface *intrfc = NULL;
  	struct datalink_proto *datalink;
  
  	if (!dev)
  		goto out;
  
  	/* Check addresses are suitable */
  	if (dev->addr_len > IPX_NODE_LEN)
  		goto out;
  
  	switch (ntohs(dlink_type)) {
  	case ETH_P_IPX:		datalink = pEII_datalink;	break;
  	case ETH_P_802_2:	datalink = p8022_datalink;	break;
  	case ETH_P_SNAP:	datalink = pSNAP_datalink;	break;
  	case ETH_P_802_3:	datalink = p8023_datalink;	break;
  	default:		goto out;
  	}
  
  	intrfc = ipxitf_alloc(dev, 0, dlink_type, datalink, 0,
  				dev->hard_header_len + datalink->header_length);
  
  	if (intrfc) {
  		memset(intrfc->if_node, 0, IPX_NODE_LEN);
  		memcpy((char *)&(intrfc->if_node[IPX_NODE_LEN-dev->addr_len]),
  			dev->dev_addr, dev->addr_len);
  		spin_lock_init(&intrfc->if_sklist_lock);
  		atomic_set(&intrfc->refcnt, 1);
  		ipxitf_insert(intrfc);
  		dev_hold(dev);
  	}
  
  out:
  	return intrfc;
  }
  
  static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
  {
  	int rc = -EINVAL;
  	struct ifreq ifr;
  	int val;
  
  	switch (cmd) {
  	case SIOCSIFADDR: {
  		struct sockaddr_ipx *sipx;
  		struct ipx_interface_definition f;
  
  		rc = -EFAULT;
  		if (copy_from_user(&ifr, arg, sizeof(ifr)))
  			break;
  		sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
  		rc = -EINVAL;
  		if (sipx->sipx_family != AF_IPX)
  			break;
  		f.ipx_network = sipx->sipx_network;
  		memcpy(f.ipx_device, ifr.ifr_name,
  			sizeof(f.ipx_device));
  		memcpy(f.ipx_node, sipx->sipx_node, IPX_NODE_LEN);
  		f.ipx_dlink_type = sipx->sipx_type;
  		f.ipx_special = sipx->sipx_special;
  
  		if (sipx->sipx_action == IPX_DLTITF)
  			rc = ipxitf_delete(&f);
  		else
  			rc = ipxitf_create(&f);
  		break;
  	}
  	case SIOCGIFADDR: {
  		struct sockaddr_ipx *sipx;
  		struct ipx_interface *ipxif;
  		struct net_device *dev;
  
  		rc = -EFAULT;
  		if (copy_from_user(&ifr, arg, sizeof(ifr)))
  			break;
  		sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
  		dev  = __dev_get_by_name(&init_net, ifr.ifr_name);
  		rc   = -ENODEV;
  		if (!dev)
  			break;
  		ipxif = ipxitf_find_using_phys(dev,
  					   ipx_map_frame_type(sipx->sipx_type));
  		rc = -EADDRNOTAVAIL;
  		if (!ipxif)
  			break;
  
  		sipx->sipx_family	= AF_IPX;
  		sipx->sipx_network	= ipxif->if_netnum;
  		memcpy(sipx->sipx_node, ipxif->if_node,
  			sizeof(sipx->sipx_node));
  		rc = -EFAULT;
  		if (copy_to_user(arg, &ifr, sizeof(ifr)))
  			break;
  		ipxitf_put(ipxif);
  		rc = 0;
  		break;
  	}
  	case SIOCAIPXITFCRT:
  		rc = -EFAULT;
  		if (get_user(val, (unsigned char __user *) arg))
  			break;
  		rc = 0;
  		ipxcfg_auto_create_interfaces = val;
  		break;
  	case SIOCAIPXPRISLT:
  		rc = -EFAULT;
  		if (get_user(val, (unsigned char __user *) arg))
  			break;
  		rc = 0;
  		ipxcfg_set_auto_select(val);
  		break;
  	}
  
  	return rc;
  }
  
  /*
   *	Checksum routine for IPX
   */
  
  /* Note: We assume ipx_tctrl==0 and htons(length)==ipx_pktsize */
  /* This functions should *not* mess with packet contents */
  
  __be16 ipx_cksum(struct ipxhdr *packet, int length)
  {
  	/*
  	 *	NOTE: sum is a net byte order quantity, which optimizes the
  	 *	loop. This only works on big and little endian machines. (I
  	 *	don't know of a machine that isn't.)
  	 */
  	/* handle the first 3 words separately; checksum should be skipped
  	 * and ipx_tctrl masked out */
  	__u16 *p = (__u16 *)packet;
  	__u32 sum = p[1] + (p[2] & (__force u16)htons(0x00ff));
  	__u32 i = (length >> 1) - 3; /* Number of remaining complete words */
  
  	/* Loop through them */
  	p += 3;
  	while (i--)
  		sum += *p++;
  
  	/* Add on the last part word if it exists */
  	if (packet->ipx_pktsize & htons(1))
  		sum += (__force u16)htons(0xff00) & *p;
  
  	/* Do final fixup */
  	sum = (sum & 0xffff) + (sum >> 16);
  
  	/* It's a pity there's no concept of carry in C */
  	if (sum >= 0x10000)
  		sum++;
  
  	/*
  	 * Leave 0 alone; we don't want 0xffff here.  Note that we can't get
  	 * here with 0x10000, so this check is the same as ((__u16)sum)
  	 */
  	if (sum)
  		sum = ~sum;
  
  	return (__force __be16)sum;
  }
  
  const char *ipx_frame_name(__be16 frame)
  {
  	char* rc = "None";
  
  	switch (ntohs(frame)) {
  	case ETH_P_IPX:		rc = "EtherII";	break;
  	case ETH_P_802_2:	rc = "802.2";	break;
  	case ETH_P_SNAP:	rc = "SNAP";	break;
  	case ETH_P_802_3:	rc = "802.3";	break;
  	case ETH_P_TR_802_2:	rc = "802.2TR";	break;
  	}
  
  	return rc;
  }
  
  const char *ipx_device_name(struct ipx_interface *intrfc)
  {
  	return intrfc->if_internal ? "Internal" :
  		intrfc->if_dev ? intrfc->if_dev->name : "Unknown";
  }
  
  /* Handling for system calls applied via the various interfaces to an IPX
   * socket object. */
  
  static int ipx_setsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, unsigned int optlen)
  {
  	struct sock *sk = sock->sk;
  	int opt;
  	int rc = -EINVAL;
  
  	if (optlen != sizeof(int))
  		goto out;
  
  	rc = -EFAULT;
  	if (get_user(opt, (unsigned int __user *)optval))
  		goto out;
  
  	rc = -ENOPROTOOPT;
  	if (!(level == SOL_IPX && optname == IPX_TYPE))
  		goto out;
  
  	ipx_sk(sk)->type = opt;
  	rc = 0;
  out:
  	return rc;
  }
  
  static int ipx_getsockopt(struct socket *sock, int level, int optname,
  	char __user *optval, int __user *optlen)
  {
  	struct sock *sk = sock->sk;
  	int val = 0;
  	int len;
  	int rc = -ENOPROTOOPT;
  
  	if (!(level == SOL_IPX && optname == IPX_TYPE))
  		goto out;
  
  	val = ipx_sk(sk)->type;
  
  	rc = -EFAULT;
  	if (get_user(len, optlen))
  		goto out;
  
  	len = min_t(unsigned int, len, sizeof(int));
  	rc = -EINVAL;
  	if(len < 0)
  		goto out;
  
  	rc = -EFAULT;
  	if (put_user(len, optlen) || copy_to_user(optval, &val, len))
  		goto out;
  
  	rc = 0;
  out:
  	return rc;
  }
  
  static struct proto ipx_proto = {
  	.name	  = "IPX",
  	.owner	  = THIS_MODULE,
  	.obj_size = sizeof(struct ipx_sock),
  };
  
  static int ipx_create(struct net *net, struct socket *sock, int protocol)
  {
  	int rc = -ESOCKTNOSUPPORT;
  	struct sock *sk;
  
  	if (net != &init_net)
  		return -EAFNOSUPPORT;
  
  	/*
  	 * SPX support is not anymore in the kernel sources. If you want to
  	 * ressurrect it, completing it and making it understand shared skbs,
  	 * be fully multithreaded, etc, grab the sources in an early 2.5 kernel
  	 * tree.
  	 */
  	if (sock->type != SOCK_DGRAM)
  		goto out;
  
  	rc = -ENOMEM;
  	sk = sk_alloc(net, PF_IPX, GFP_KERNEL, &ipx_proto);
  	if (!sk)
  		goto out;
  
  	sk_refcnt_debug_inc(sk);
  	sock_init_data(sock, sk);
  	sk->sk_no_check = 1;		/* Checksum off by default */
  	sock->ops = &ipx_dgram_ops;
  	rc = 0;
  out:
  	return rc;
  }
  
  static int ipx_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  
  	if (!sk)
  		goto out;
  
  	if (!sock_flag(sk, SOCK_DEAD))
  		sk->sk_state_change(sk);
  
  	sock_set_flag(sk, SOCK_DEAD);
  	sock->sk = NULL;
  	sk_refcnt_debug_release(sk);
  	ipx_destroy_socket(sk);
  out:
  	return 0;
  }
  
  /* caller must hold a reference to intrfc */
  
  static __be16 ipx_first_free_socketnum(struct ipx_interface *intrfc)
  {
  	unsigned short socketNum = intrfc->if_sknum;
  
  	spin_lock_bh(&intrfc->if_sklist_lock);
  
  	if (socketNum < IPX_MIN_EPHEMERAL_SOCKET)
  		socketNum = IPX_MIN_EPHEMERAL_SOCKET;
  
  	while (__ipxitf_find_socket(intrfc, htons(socketNum)))
  		if (socketNum > IPX_MAX_EPHEMERAL_SOCKET)
  			socketNum = IPX_MIN_EPHEMERAL_SOCKET;
  		else
  			socketNum++;
  
  	spin_unlock_bh(&intrfc->if_sklist_lock);
  	intrfc->if_sknum = socketNum;
  
  	return htons(socketNum);
  }
  
  static int ipx_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sock *sk = sock->sk;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	struct ipx_interface *intrfc;
  	struct sockaddr_ipx *addr = (struct sockaddr_ipx *)uaddr;
  	int rc = -EINVAL;
  
  	if (!sock_flag(sk, SOCK_ZAPPED) || addr_len != sizeof(struct sockaddr_ipx))
  		goto out;
  
  	intrfc = ipxitf_find_using_net(addr->sipx_network);
  	rc = -EADDRNOTAVAIL;
  	if (!intrfc)
  		goto out;
  
  	if (!addr->sipx_port) {
  		addr->sipx_port = ipx_first_free_socketnum(intrfc);
  		rc = -EINVAL;
  		if (!addr->sipx_port)
  			goto out_put;
  	}
  
  	/* protect IPX system stuff like routing/sap */
  	rc = -EACCES;
  	if (ntohs(addr->sipx_port) < IPX_MIN_EPHEMERAL_SOCKET &&
  	    !capable(CAP_NET_ADMIN))
  		goto out_put;
  
  	ipxs->port = addr->sipx_port;
  
  #ifdef CONFIG_IPX_INTERN
  	if (intrfc == ipx_internal_net) {
  		/* The source address is to be set explicitly if the
  		 * socket is to be bound on the internal network. If a
  		 * node number 0 was specified, the default is used.
  		 */
  
  		rc = -EINVAL;
  		if (!memcmp(addr->sipx_node, ipx_broadcast_node, IPX_NODE_LEN))
  			goto out_put;
  		if (!memcmp(addr->sipx_node, ipx_this_node, IPX_NODE_LEN))
  			memcpy(ipxs->node, intrfc->if_node, IPX_NODE_LEN);
  		else
  			memcpy(ipxs->node, addr->sipx_node, IPX_NODE_LEN);
  
  		rc = -EADDRINUSE;
  		if (ipxitf_find_internal_socket(intrfc, ipxs->node,
  						ipxs->port)) {
  			SOCK_DEBUG(sk,
  				"IPX: bind failed because port %X in use.\n",
  				ntohs(addr->sipx_port));
  			goto out_put;
  		}
  	} else {
  		/* Source addresses are easy. It must be our
  		 * network:node pair for an interface routed to IPX
  		 * with the ipx routing ioctl()
  		 */
  
  		memcpy(ipxs->node, intrfc->if_node, IPX_NODE_LEN);
  
  		rc = -EADDRINUSE;
  		if (ipxitf_find_socket(intrfc, addr->sipx_port)) {
  			SOCK_DEBUG(sk,
  				"IPX: bind failed because port %X in use.\n",
  				ntohs(addr->sipx_port));
  			goto out_put;
  		}
  	}
  
  #else	/* !def CONFIG_IPX_INTERN */
  
  	/* Source addresses are easy. It must be our network:node pair for
  	   an interface routed to IPX with the ipx routing ioctl() */
  
  	rc = -EADDRINUSE;
  	if (ipxitf_find_socket(intrfc, addr->sipx_port)) {
  		SOCK_DEBUG(sk, "IPX: bind failed because port %X in use.\n",
  				ntohs((int)addr->sipx_port));
  		goto out_put;
  	}
  
  #endif	/* CONFIG_IPX_INTERN */
  
  	ipxitf_insert_socket(intrfc, sk);
  	sock_reset_flag(sk, SOCK_ZAPPED);
  
  	rc = 0;
  out_put:
  	ipxitf_put(intrfc);
  out:
  	return rc;
  }
  
  static int ipx_connect(struct socket *sock, struct sockaddr *uaddr,
  	int addr_len, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	struct sockaddr_ipx *addr;
  	int rc = -EINVAL;
  	struct ipx_route *rt;
  
  	sk->sk_state	= TCP_CLOSE;
  	sock->state 	= SS_UNCONNECTED;
  
  	if (addr_len != sizeof(*addr))
  		goto out;
  	addr = (struct sockaddr_ipx *)uaddr;
  
  	/* put the autobinding in */
  	if (!ipxs->port) {
  		struct sockaddr_ipx uaddr;
  
  		uaddr.sipx_port		= 0;
  		uaddr.sipx_network 	= 0;
  
  #ifdef CONFIG_IPX_INTERN
  		rc = -ENETDOWN;
  		if (!ipxs->intrfc)
  			goto out; /* Someone zonked the iface */
  		memcpy(uaddr.sipx_node, ipxs->intrfc->if_node,
  			IPX_NODE_LEN);
  #endif	/* CONFIG_IPX_INTERN */
  
  		rc = ipx_bind(sock, (struct sockaddr *)&uaddr,
  			      sizeof(struct sockaddr_ipx));
  		if (rc)
  			goto out;
  	}
  
  	/* We can either connect to primary network or somewhere
  	 * we can route to */
  	rt = ipxrtr_lookup(addr->sipx_network);
  	rc = -ENETUNREACH;
  	if (!rt && !(!addr->sipx_network && ipx_primary_net))
  		goto out;
  
  	ipxs->dest_addr.net  = addr->sipx_network;
  	ipxs->dest_addr.sock = addr->sipx_port;
  	memcpy(ipxs->dest_addr.node, addr->sipx_node, IPX_NODE_LEN);
  	ipxs->type = addr->sipx_type;
  
  	if (sock->type == SOCK_DGRAM) {
  		sock->state 	= SS_CONNECTED;
  		sk->sk_state 	= TCP_ESTABLISHED;
  	}
  
  	if (rt)
  		ipxrtr_put(rt);
  	rc = 0;
  out:
  	return rc;
  }
  
  
  static int ipx_getname(struct socket *sock, struct sockaddr *uaddr,
  			int *uaddr_len, int peer)
  {
  	struct ipx_address *addr;
  	struct sockaddr_ipx sipx;
  	struct sock *sk = sock->sk;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	int rc;
  
  	*uaddr_len = sizeof(struct sockaddr_ipx);
  
  	if (peer) {
  		rc = -ENOTCONN;
  		if (sk->sk_state != TCP_ESTABLISHED)
  			goto out;
  
  		addr = &ipxs->dest_addr;
  		sipx.sipx_network	= addr->net;
  		sipx.sipx_port		= addr->sock;
  		memcpy(sipx.sipx_node, addr->node, IPX_NODE_LEN);
  	} else {
  		if (ipxs->intrfc) {
  			sipx.sipx_network = ipxs->intrfc->if_netnum;
  #ifdef CONFIG_IPX_INTERN
  			memcpy(sipx.sipx_node, ipxs->node, IPX_NODE_LEN);
  #else
  			memcpy(sipx.sipx_node, ipxs->intrfc->if_node,
  				IPX_NODE_LEN);
  #endif	/* CONFIG_IPX_INTERN */
  
  		} else {
  			sipx.sipx_network = 0;
  			memset(sipx.sipx_node, '\0', IPX_NODE_LEN);
  		}
  
  		sipx.sipx_port = ipxs->port;
  	}
  
  	sipx.sipx_family = AF_IPX;
  	sipx.sipx_type	 = ipxs->type;
  	sipx.sipx_zero	 = 0;
  	memcpy(uaddr, &sipx, sizeof(sipx));
  
  	rc = 0;
  out:
  	return rc;
  }
  
  static int ipx_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
  {
  	/* NULL here for pt means the packet was looped back */
  	struct ipx_interface *intrfc;
  	struct ipxhdr *ipx;
  	u16 ipx_pktsize;
  	int rc = 0;
  
  	if (!net_eq(dev_net(dev), &init_net))
  		goto drop;
  
  	/* Not ours */
  	if (skb->pkt_type == PACKET_OTHERHOST)
  		goto drop;
  
  	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
  		goto out;
  
  	if (!pskb_may_pull(skb, sizeof(struct ipxhdr)))
  		goto drop;
  
  	ipx_pktsize = ntohs(ipx_hdr(skb)->ipx_pktsize);
  
  	/* Too small or invalid header? */
  	if (ipx_pktsize < sizeof(struct ipxhdr) ||
  	    !pskb_may_pull(skb, ipx_pktsize))
  		goto drop;
  
  	ipx = ipx_hdr(skb);
  	if (ipx->ipx_checksum != IPX_NO_CHECKSUM &&
  	   ipx->ipx_checksum != ipx_cksum(ipx, ipx_pktsize))
  		goto drop;
  
  	IPX_SKB_CB(skb)->ipx_tctrl	= ipx->ipx_tctrl;
  	IPX_SKB_CB(skb)->ipx_dest_net	= ipx->ipx_dest.net;
  	IPX_SKB_CB(skb)->ipx_source_net = ipx->ipx_source.net;
  
  	/* Determine what local ipx endpoint this is */
  	intrfc = ipxitf_find_using_phys(dev, pt->type);
  	if (!intrfc) {
  		if (ipxcfg_auto_create_interfaces &&
  		   IPX_SKB_CB(skb)->ipx_dest_net) {
  			intrfc = ipxitf_auto_create(dev, pt->type);
  			if (intrfc)
  				ipxitf_hold(intrfc);
  		}
  
  		if (!intrfc)	/* Not one of ours */
  				/* or invalid packet for auto creation */
  			goto drop;
  	}
  
  	rc = ipxitf_rcv(intrfc, skb);
  	ipxitf_put(intrfc);
  	goto out;
  drop:
  	kfree_skb(skb);
  out:
  	return rc;
  }
  
  static int ipx_sendmsg(struct kiocb *iocb, struct socket *sock,
  	struct msghdr *msg, size_t len)
  {
  	struct sock *sk = sock->sk;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	struct sockaddr_ipx *usipx = (struct sockaddr_ipx *)msg->msg_name;
  	struct sockaddr_ipx local_sipx;
  	int rc = -EINVAL;
  	int flags = msg->msg_flags;
  
  	/* Socket gets bound below anyway */
  /*	if (sk->sk_zapped)
  		return -EIO; */	/* Socket not bound */
  	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
  		goto out;
  
  	/* Max possible packet size limited by 16 bit pktsize in header */
  	if (len >= 65535 - sizeof(struct ipxhdr))
  		goto out;
  
  	if (usipx) {
  		if (!ipxs->port) {
  			struct sockaddr_ipx uaddr;
  
  			uaddr.sipx_port		= 0;
  			uaddr.sipx_network	= 0;
  #ifdef CONFIG_IPX_INTERN
  			rc = -ENETDOWN;
  			if (!ipxs->intrfc)
  				goto out; /* Someone zonked the iface */
  			memcpy(uaddr.sipx_node, ipxs->intrfc->if_node,
  				IPX_NODE_LEN);
  #endif
  			rc = ipx_bind(sock, (struct sockaddr *)&uaddr,
  					sizeof(struct sockaddr_ipx));
  			if (rc)
  				goto out;
  		}
  
  		rc = -EINVAL;
  		if (msg->msg_namelen < sizeof(*usipx) ||
  		    usipx->sipx_family != AF_IPX)
  			goto out;
  	} else {
  		rc = -ENOTCONN;
  		if (sk->sk_state != TCP_ESTABLISHED)
  			goto out;
  
  		usipx = &local_sipx;
  		usipx->sipx_family 	= AF_IPX;
  		usipx->sipx_type 	= ipxs->type;
  		usipx->sipx_port 	= ipxs->dest_addr.sock;
  		usipx->sipx_network 	= ipxs->dest_addr.net;
  		memcpy(usipx->sipx_node, ipxs->dest_addr.node, IPX_NODE_LEN);
  	}
  
  	rc = ipxrtr_route_packet(sk, usipx, msg->msg_iov, len,
  				 flags & MSG_DONTWAIT);
  	if (rc >= 0)
  		rc = len;
  out:
  	return rc;
  }
  
  
  static int ipx_recvmsg(struct kiocb *iocb, struct socket *sock,
  		struct msghdr *msg, size_t size, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct ipx_sock *ipxs = ipx_sk(sk);
  	struct sockaddr_ipx *sipx = (struct sockaddr_ipx *)msg->msg_name;
  	struct ipxhdr *ipx = NULL;
  	struct sk_buff *skb;
  	int copied, rc;
  
  	/* put the autobinding in */
  	if (!ipxs->port) {
  		struct sockaddr_ipx uaddr;
  
  		uaddr.sipx_port		= 0;
  		uaddr.sipx_network 	= 0;
  
  #ifdef CONFIG_IPX_INTERN
  		rc = -ENETDOWN;
  		if (!ipxs->intrfc)
  			goto out; /* Someone zonked the iface */
  		memcpy(uaddr.sipx_node, ipxs->intrfc->if_node, IPX_NODE_LEN);
  #endif	/* CONFIG_IPX_INTERN */
  
  		rc = ipx_bind(sock, (struct sockaddr *)&uaddr,
  			      sizeof(struct sockaddr_ipx));
  		if (rc)
  			goto out;
  	}
  
  	rc = -ENOTCONN;
  	if (sock_flag(sk, SOCK_ZAPPED))
  		goto out;
  
  	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
  				flags & MSG_DONTWAIT, &rc);
  	if (!skb)
  		goto out;
  
  	ipx 	= ipx_hdr(skb);
  	copied 	= ntohs(ipx->ipx_pktsize) - sizeof(struct ipxhdr);
  	if (copied > size) {
  		copied = size;
  		msg->msg_flags |= MSG_TRUNC;
  	}
  
  	rc = skb_copy_datagram_iovec(skb, sizeof(struct ipxhdr), msg->msg_iov,
  				     copied);
  	if (rc)
  		goto out_free;
  	if (skb->tstamp.tv64)
  		sk->sk_stamp = skb->tstamp;
  
  	msg->msg_namelen = sizeof(*sipx);
  
  	if (sipx) {
  		sipx->sipx_family	= AF_IPX;
  		sipx->sipx_port		= ipx->ipx_source.sock;
  		memcpy(sipx->sipx_node, ipx->ipx_source.node, IPX_NODE_LEN);
  		sipx->sipx_network	= IPX_SKB_CB(skb)->ipx_source_net;
  		sipx->sipx_type 	= ipx->ipx_type;
  		sipx->sipx_zero		= 0;
  	}
  	rc = copied;
  
  out_free:
  	skb_free_datagram(sk, skb);
  out:
  	return rc;
  }
  
  
  static int ipx_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	int rc = 0;
  	long amount = 0;
  	struct sock *sk = sock->sk;
  	void __user *argp = (void __user *)arg;
  
  	switch (cmd) {
  	case TIOCOUTQ:
  		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
  		if (amount < 0)
  			amount = 0;
  		rc = put_user(amount, (int __user *)argp);
  		break;
  	case TIOCINQ: {
  		struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
  		/* These two are safe on a single CPU system as only
  		 * user tasks fiddle here */
  		if (skb)
  			amount = skb->len - sizeof(struct ipxhdr);
  		rc = put_user(amount, (int __user *)argp);
  		break;
  	}
  	case SIOCADDRT:
  	case SIOCDELRT:
  		rc = -EPERM;
  		if (capable(CAP_NET_ADMIN))
  			rc = ipxrtr_ioctl(cmd, argp);
  		break;
  	case SIOCSIFADDR:
  	case SIOCAIPXITFCRT:
  	case SIOCAIPXPRISLT:
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))
  			break;
  	case SIOCGIFADDR:
  		rc = ipxitf_ioctl(cmd, argp);
  		break;
  	case SIOCIPXCFGDATA:
  		rc = ipxcfg_get_config_data(argp);
  		break;
  	case SIOCIPXNCPCONN:
  		/*
  		 * This socket wants to take care of the NCP connection
  		 * handed to us in arg.
  		 */
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))
  			break;
  		rc = get_user(ipx_sk(sk)->ipx_ncp_conn,
  			      (const unsigned short __user *)argp);
  		break;
  	case SIOCGSTAMP:
  		rc = -EINVAL;
  		if (sk)
  			rc = sock_get_timestamp(sk, argp);
  		break;
  	case SIOCGIFDSTADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFNETMASK:
  		rc = -EINVAL;
  		break;
  	default:
  		rc = -ENOIOCTLCMD;
  		break;
  	}
  
  	return rc;
  }
  
  
  #ifdef CONFIG_COMPAT
  static int ipx_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	/*
  	 * These 4 commands use same structure on 32bit and 64bit.  Rest of IPX
  	 * commands is handled by generic ioctl code.  As these commands are
  	 * SIOCPROTOPRIVATE..SIOCPROTOPRIVATE+3, they cannot be handled by generic
  	 * code.
  	 */
  	switch (cmd) {
  	case SIOCAIPXITFCRT:
  	case SIOCAIPXPRISLT:
  	case SIOCIPXCFGDATA:
  	case SIOCIPXNCPCONN:
  		return ipx_ioctl(sock, cmd, arg);
  	default:
  		return -ENOIOCTLCMD;
  	}
  }
  #endif
  
  
  /*
   * Socket family declarations
   */
  
  static struct net_proto_family ipx_family_ops = {
  	.family		= PF_IPX,
  	.create		= ipx_create,
  	.owner		= THIS_MODULE,
  };
  
  static const struct proto_ops SOCKOPS_WRAPPED(ipx_dgram_ops) = {
  	.family		= PF_IPX,
  	.owner		= THIS_MODULE,
  	.release	= ipx_release,
  	.bind		= ipx_bind,
  	.connect	= ipx_connect,
  	.socketpair	= sock_no_socketpair,
  	.accept		= sock_no_accept,
  	.getname	= ipx_getname,
  	.poll		= datagram_poll,
  	.ioctl		= ipx_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= ipx_compat_ioctl,
  #endif
  	.listen		= sock_no_listen,
  	.shutdown	= sock_no_shutdown, /* FIXME: support shutdown */
  	.setsockopt	= ipx_setsockopt,
  	.getsockopt	= ipx_getsockopt,
  	.sendmsg	= ipx_sendmsg,
  	.recvmsg	= ipx_recvmsg,
  	.mmap		= sock_no_mmap,
  	.sendpage	= sock_no_sendpage,
  };
  
  SOCKOPS_WRAP(ipx_dgram, PF_IPX);
  
  static struct packet_type ipx_8023_packet_type __read_mostly = {
  	.type		= cpu_to_be16(ETH_P_802_3),
  	.func		= ipx_rcv,
  };
  
  static struct packet_type ipx_dix_packet_type __read_mostly = {
  	.type		= cpu_to_be16(ETH_P_IPX),
  	.func		= ipx_rcv,
  };
  
  static struct notifier_block ipx_dev_notifier = {
  	.notifier_call	= ipxitf_device_event,
  };
  
  extern struct datalink_proto *make_EII_client(void);
  extern void destroy_EII_client(struct datalink_proto *);
  
  static const unsigned char ipx_8022_type = 0xE0;
  static const unsigned char ipx_snap_id[5] = { 0x0, 0x0, 0x0, 0x81, 0x37 };
  static const char ipx_EII_err_msg[] __initconst =
  	KERN_CRIT "IPX: Unable to register with Ethernet II\n";
  static const char ipx_8023_err_msg[] __initconst =
  	KERN_CRIT "IPX: Unable to register with 802.3\n";
  static const char ipx_llc_err_msg[] __initconst =
  	KERN_CRIT "IPX: Unable to register with 802.2\n";
  static const char ipx_snap_err_msg[] __initconst =
  	KERN_CRIT "IPX: Unable to register with SNAP\n";
  
  static int __init ipx_init(void)
  {
  	int rc = proto_register(&ipx_proto, 1);
  
  	if (rc != 0)
  		goto out;
  
  	sock_register(&ipx_family_ops);
  
  	pEII_datalink = make_EII_client();
  	if (pEII_datalink)
  		dev_add_pack(&ipx_dix_packet_type);
  	else
  		printk(ipx_EII_err_msg);
  
  	p8023_datalink = make_8023_client();
  	if (p8023_datalink)
  		dev_add_pack(&ipx_8023_packet_type);
  	else
  		printk(ipx_8023_err_msg);
  
  	p8022_datalink = register_8022_client(ipx_8022_type, ipx_rcv);
  	if (!p8022_datalink)
  		printk(ipx_llc_err_msg);
  
  	pSNAP_datalink = register_snap_client(ipx_snap_id, ipx_rcv);
  	if (!pSNAP_datalink)
  		printk(ipx_snap_err_msg);
  
  	register_netdevice_notifier(&ipx_dev_notifier);
  	ipx_register_sysctl();
  	ipx_proc_init();
  out:
  	return rc;
  }
  
  static void __exit ipx_proto_finito(void)
  {
  	ipx_proc_exit();
  	ipx_unregister_sysctl();
  
  	unregister_netdevice_notifier(&ipx_dev_notifier);
  
  	ipxitf_cleanup();
  
  	if (pSNAP_datalink) {
  		unregister_snap_client(pSNAP_datalink);
  		pSNAP_datalink = NULL;
  	}
  
  	if (p8022_datalink) {
  		unregister_8022_client(p8022_datalink);
  		p8022_datalink = NULL;
  	}
  
  	dev_remove_pack(&ipx_8023_packet_type);
  	if (p8023_datalink) {
  		destroy_8023_client(p8023_datalink);
  		p8023_datalink = NULL;
  	}
  
  	dev_remove_pack(&ipx_dix_packet_type);
  	if (pEII_datalink) {
  		destroy_EII_client(pEII_datalink);
  		pEII_datalink = NULL;
  	}
  
  	proto_unregister(&ipx_proto);
  	sock_unregister(ipx_family_ops.family);
  }
  
  module_init(ipx_init);
  module_exit(ipx_proto_finito);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NETPROTO(PF_IPX);
  