/*
 *      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.
 *
 *      Revision 0.21:  Uses the new generic socket option code.
 *      Revision 0.22:  Gcc clean ups and drop out device registration. Use the
 *                      new multi-protocol edition of hard_header
 *      Revision 0.23:  IPX /proc by Mark Evans. Adding a route will
 *                      will overwrite any existing route to the same network.
 *      Revision 0.24:  Supports new /proc with no 4K limit
 *      Revision 0.25:  Add ephemeral sockets, passive local network
 *                      identification, support for local net 0 and
 *                      multiple datalinks <Greg Page>
 *      Revision 0.26:  Device drop kills IPX routes via it. (needed for module)
 *      Revision 0.27:  Autobind <Mark Evans>
 *      Revision 0.28:  Small fix for multiple local networks <Thomas Winder>
 *      Revision 0.29:  Assorted major errors removed <Mark Evans>
 *                      Small correction to promisc mode error fix <Alan Cox>
 *                      Asynchronous I/O support. Changed to use notifiers
 *                      and the newer packet_type stuff. Assorted major
 *                      fixes <Alejandro Liu>
 *      Revision 0.30:  Moved to net/ipx/...    <Alan Cox>
 *                      Don't set address length on recvfrom that errors.
 *                      Incorrect verify_area.
 *      Revision 0.31:  New sk_buffs. This still needs a lot of 
 *                      testing. <Alan Cox>
 *      Revision 0.32:  Using sock_alloc_send_skb, firewall hooks. <Alan Cox>
 *                      Supports sendmsg/recvmsg
 *      Revision 0.33:  Internal network support, routing changes, uses a
 *                      protocol private area for ipx data.
 *      Revision 0.34:  Module support. <Jim Freeman>
 *      Revision 0.35:  Checksum support. <Neil Turton>, hooked in by <Alan Cox>
 *                      Handles WIN95 discovery packets <Volker Lendecke>
 *      Revision 0.36:  Internal bump up for 2.1
 *      Revision 0.37:  Began adding POSIXisms.
 *      Revision 0.38:  Asynchronous socket stuff made current.
 *      Revision 0.39:  SPX interfaces
 *      Revision 0.40:  Tiny SIOCGSTAMP fix (chris@cybernet.co.nz)
 *      Revision 0.41:  802.2TR removed (p.norton@computer.org)
 *                      Fixed connecting to primary net,
 *                      Automatic binding on send & receive,
 *                      Martijn van Oosterhout <kleptogimp@geocities.com>
 *      Revision 042:   Multithreading - use spinlocks and refcounting to
 *                      protect some structures: ipx_interface sock list, list
 *                      of ipx interfaces, etc. 
 *                      Bugfixes - do refcounting on net_devices, check function
 *                      results, etc. Thanks to davem and freitag for
 *                      suggestions and guidance.
 *                      Arnaldo Carvalho de Melo <acme@conectiva.com.br>,
 *                      November, 2000
 *      Revision 043:   Shared SKBs, don't mangle packets, some cleanups
 *                      Arnaldo Carvalho de Melo <acme@conectiva.com.br>,
 *                      December, 2000
 *      Revision 044:   Call ipxitf_hold on NETDEV_UP (acme)
 *      Revision 045:   fix PPROP routing bug (acme)
 *      Revision 046:   Further fixes to PPROP, ipxitf_create_internal was
 *                      doing an unneeded MOD_INC_USE_COUNT, implement
 *                      sysctl for ipx_pprop_broacasting, fix the ipx sysctl
 *                      handling, making it dynamic, some cleanups, thanks to
 *                      Petr Vandrovec for review and good suggestions. (acme)
 *      Revision 047:   Cleanups, CodingStyle changes, move the ncp connection
 *                      hack out of line (acme)
 *
 *      Protect the module by a MOD_INC_USE_COUNT/MOD_DEC_USE_COUNT
 *      pair. Also, now usage count is managed this way
 *      -Count one if the auto_interface mode is on
 *      -Count one per configured interface
 *
 *      Jacques Gelinas (jacques@solucorp.qc.ca)
 *
 *
 *      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.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <net/ipx.h>
#include <linux/inet.h>
#include <linux/route.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/termios.h>      /* For TIOCOUTQ/INQ */
#include <linux/interrupt.h>
#include <net/p8022.h>
#include <net/psnap.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/if_arp.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 struct proto_ops ipx_dgram_ops;

static struct net_proto_family *spx_family_ops;

static ipx_route *ipx_routes;
static rwlock_t ipx_routes_lock = RW_LOCK_UNLOCKED;

static ipx_interface *ipx_interfaces;
static spinlock_t ipx_interfaces_lock = SPIN_LOCK_UNLOCKED;

static ipx_interface *ipx_primary_net;
static ipx_interface *ipx_internal_net;

#define IPX_SKB_CB(__skb) ((struct ipx_cb *)&((__skb)->cb[0]))

#undef IPX_REFCNT_DEBUG
#ifdef IPX_REFCNT_DEBUG
atomic_t ipx_sock_nr;
#endif

static void ipxcfg_set_auto_create(char val)
{
        if (ipxcfg_auto_create_interfaces != val) {
                if (val)
                        MOD_INC_USE_COUNT;
                else
                        MOD_DEC_USE_COUNT;

                ipxcfg_auto_create_interfaces = val;
        }
}

static void ipxcfg_set_auto_select(char val)
{
        ipxcfg_auto_select_primary = val;
        if (val && !ipx_primary_net)
                ipx_primary_net = ipx_interfaces;
}

static int ipxcfg_get_config_data(ipx_config_data *arg)
{
        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;
}

/* Handlers for the socket list. */

static inline void ipxitf_hold(ipx_interface *intrfc)
{
        atomic_inc(&intrfc->refcnt);
}

static void ipxitf_down(ipx_interface *intrfc);

static inline void ipxitf_put(ipx_interface *intrfc)
{
        if (atomic_dec_and_test(&intrfc->refcnt))
                ipxitf_down(intrfc);
}

static void __ipxitf_down(ipx_interface *intrfc);

static inline void __ipxitf_put(ipx_interface *intrfc)
{
        if (atomic_dec_and_test(&intrfc->refcnt))
                __ipxitf_down(intrfc);
}
/*
 * 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.
 */

void ipx_remove_socket(struct sock *sk)
{
        struct sock *s;
        ipx_interface *intrfc;

        /* Determine interface with which socket is associated */
        intrfc = sk->protinfo.af_ipx.intrfc;
        if (!intrfc)
                goto out;

        ipxitf_hold(intrfc);
        spin_lock_bh(&intrfc->if_sklist_lock);
        s = intrfc->if_sklist;
        if (s == sk) {
                intrfc->if_sklist = s->next;
                goto out_unlock;
        }

        while (s && s->next) {
                if (s->next == sk) {
                        s->next = sk->next;
                        goto out_unlock;
                }
                s = s->next;
        }
out_unlock:
        spin_unlock_bh(&intrfc->if_sklist_lock);
        sock_put(sk);
        ipxitf_put(intrfc);
out:    return;
}

static void ipx_destroy_socket(struct sock *sk)
{
        ipx_remove_socket(sk);
        skb_queue_purge(&sk->receive_queue);
#ifdef IPX_REFCNT_DEBUG
        atomic_dec(&ipx_sock_nr);
        printk(KERN_DEBUG "IPX socket %p released, %d are still alive\n", sk,
                        atomic_read(&ipx_sock_nr));
        if (atomic_read(&sk->refcnt) != 1)
                printk(KERN_DEBUG "Destruction sock ipx %p delayed, cnt=%d\n",
                                sk, atomic_read(&sk->refcnt));
#endif
        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.
 */
static ipx_route * ipxrtr_lookup(__u32);

/* ipxitf_clear_primary_net has to be called with ipx_interfaces_lock held */

static void ipxitf_clear_primary_net(void)
{
        ipx_primary_net = ipxcfg_auto_select_primary ? ipx_interfaces : NULL;
}

static ipx_interface *__ipxitf_find_using_phys(struct net_device *dev,
                                                unsigned short datalink)
{
        ipx_interface *i = ipx_interfaces;

        while (i && (i->if_dev != dev || i->if_dlink_type != datalink))
                i = i->if_next;

        return i;
}

static ipx_interface *ipxitf_find_using_phys(struct net_device *dev,
                                                unsigned short datalink)
{
        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;
}

static ipx_interface *ipxitf_find_using_net(__u32 net)
{
        ipx_interface *i;

        spin_lock_bh(&ipx_interfaces_lock);
        if (net)
                for (i = ipx_interfaces; i && i->if_netnum != net;
                     i = i->if_next)
                ;
        else
                i = ipx_primary_net;
        if (i)
                ipxitf_hold(i);
        spin_unlock_bh(&ipx_interfaces_lock);

        return i;
}

/* Sockets are bound to a particular IPX interface. */
static void ipxitf_insert_socket(ipx_interface *intrfc, struct sock *sk)
{
        ipxitf_hold(intrfc);
        sock_hold(sk);
        spin_lock_bh(&intrfc->if_sklist_lock);
        sk->protinfo.af_ipx.intrfc = intrfc;
        sk->next = NULL;
        if (!intrfc->if_sklist)
                intrfc->if_sklist = sk;
        else {
                struct sock *s = intrfc->if_sklist;
                while (s->next)
                        s = s->next;
                s->next = sk;
        }
        spin_unlock_bh(&intrfc->if_sklist_lock);
        ipxitf_put(intrfc);
}

/* caller must hold intrfc->if_sklist_lock */
static struct sock *__ipxitf_find_socket(ipx_interface *intrfc,
                                         unsigned short port)
{
        struct sock *s = intrfc->if_sklist;

        while (s && s->protinfo.af_ipx.port != port)
             s = s->next;

        return s;
}

/* caller must hold a reference to intrfc */
static struct sock *ipxitf_find_socket(ipx_interface *intrfc,
                                        unsigned short 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(ipx_interface *intrfc,
                            unsigned char *node, unsigned short port)
{
        struct sock *s;

        ipxitf_hold(intrfc);
        spin_lock_bh(&intrfc->if_sklist_lock);
        s = intrfc->if_sklist;

        while (s) {
                if (s->protinfo.af_ipx.port == port &&
                    !memcmp(node, s->protinfo.af_ipx.node, IPX_NODE_LEN))
                        break;
                s = s->next;
        }
        spin_unlock_bh(&intrfc->if_sklist_lock);
        ipxitf_put(intrfc);

        return s;
}
#endif

static void ipxrtr_del_routes(ipx_interface *);

static void __ipxitf_down(ipx_interface *intrfc)
{
        struct sock *s, *t;

        /* Delete all routes associated with this interface */
        ipxrtr_del_routes(intrfc);

        spin_lock_bh(&intrfc->if_sklist_lock);
        /* error sockets */
        for (s = intrfc->if_sklist; s;) {
                s->err = ENOLINK;
                s->error_report(s);
                s->protinfo.af_ipx.intrfc = NULL;
                s->protinfo.af_ipx.port   = 0;
                s->zapped = 1;  /* Indicates it is no longer bound */
                t = s;
                s = s->next;
                t->next = NULL;
        }
        intrfc->if_sklist = NULL;
        spin_unlock_bh(&intrfc->if_sklist_lock);

        /* remove this interface from list */
        if (intrfc == ipx_interfaces)
                ipx_interfaces = intrfc->if_next;
        else {
                ipx_interface *i = ipx_interfaces;
                while (i && i->if_next != intrfc)
                     i = i->if_next;
                if (i && i->if_next == intrfc)
                        i->if_next = intrfc->if_next;
        }

        /* 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);
        MOD_DEC_USE_COUNT;
}

static void ipxitf_down(ipx_interface *intrfc)
{
        spin_lock_bh(&ipx_interfaces_lock);
        __ipxitf_down(intrfc);
        spin_unlock_bh(&ipx_interfaces_lock);
}

static int ipxitf_device_event(struct notifier_block *notifier,
                                unsigned long event, void *ptr)
{
        struct net_device *dev = ptr;
        ipx_interface *i, *tmp;

        if (event != NETDEV_DOWN && event != NETDEV_UP)
                goto out;

        spin_lock_bh(&ipx_interfaces_lock);
        for (i = ipx_interfaces; i;) {
                tmp = i->if_next;
                if (i->if_dev == dev) {
                        if (event == NETDEV_UP)
                                ipxitf_hold(i);
                        else
                                __ipxitf_put(i);
                }
                i = tmp;
        }
        spin_unlock_bh(&ipx_interfaces_lock);
out:    return NOTIFY_DONE;
}

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(ipx_interface *intrfc, struct sk_buff *skb,
                                int copy)
{
        struct ipxhdr *ipx = skb->nh.ipxh;
        int is_broadcast = !memcmp(ipx->ipx_dest.node, ipx_broadcast_node,
                                   IPX_NODE_LEN);
        struct sock *s;
        int ret;

        spin_lock_bh(&intrfc->if_sklist_lock);
        s = intrfc->if_sklist;

        while (s) {
                if (s->protinfo.af_ipx.port == ipx->ipx_dest.sock &&
                    (is_broadcast || !memcmp(ipx->ipx_dest.node,
                                             s->protinfo.af_ipx.node,
                                             IPX_NODE_LEN))) {
                        /* We found a socket to which to send */
                        struct sk_buff *skb1;

                        if (copy) {
                                skb1 = skb_clone(skb, GFP_ATOMIC);
                                ret = -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;
                }
                s = s->next;
        }

        /* skb was solely for us, and we did not make a copy, so free it. */
        if (!copy)
                kfree_skb(skb);

        ret = 0;
out:    spin_unlock_bh(&intrfc->if_sklist_lock);
        return ret;
}
#else
static struct sock *ncp_connection_hack(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) {
                /* 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);
                for (sk = intrfc->if_sklist;
                     sk && sk->protinfo.af_ipx.ipx_ncp_conn != connection;
                     sk = sk->next);
                if (sk)
                        sock_hold(sk);
                spin_unlock_bh(&intrfc->if_sklist_lock);
        }
        return sk;
}

static int ipxitf_demux_socket(ipx_interface *intrfc, struct sk_buff *skb,
                                int copy)
{
        struct ipxhdr *ipx = skb->nh.ipxh;
        struct sock *sock1 = NULL, *sock2 = NULL;
        struct sk_buff *skb1 = NULL, *skb2 = NULL;
        int ret;

        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.
         */
        if (!sock1 && !sock2) {
                if (!copy)
                        kfree_skb(skb);
                return 0;
        }

        /*
         * 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;

        ret = -ENOMEM;
        if (!skb1)
                goto out;

        /* 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);

        ret = -ENOMEM;
        if (!skb2)
                goto out;

        if (sock2)
                ipxitf_def_skb_handler(sock2, skb2);

        ret = 0;
out:    if (sock1)
                sock_put(sock1);
        if (sock2)
                sock_put(sock2);
        return ret;
}
#endif  /* CONFIG_IPX_INTERN */

static struct sk_buff *ipxitf_adjust_skbuff(ipx_interface *intrfc,
                                            struct sk_buff *skb)
{
        struct sk_buff *skb2;
        int in_offset = skb->h.raw - 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);
                skb2->nh.raw = skb2->h.raw = skb_put(skb2, skb->len);
                memcpy(skb2->h.raw, skb->h.raw, 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 */

static int ipxitf_send(ipx_interface *intrfc, struct sk_buff *skb, char *node)
{
        struct ipxhdr *ipx = skb->nh.ipxh;
        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) {
                u32 *last_hop = (u32 *)(((u8 *) skb->data) +
                                sizeof(struct ipxhdr) +
                                IPX_SKB_CB(skb)->last_hop.index *
                                sizeof(u32));
                *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 its 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   = __constant_htons(ETH_P_IPX);
        dl->datalink_header(dl, skb, dest_node);

        /* Send it out */
        dev_queue_xmit(skb);
out:    return 0;
}

static int ipxrtr_add_route(__u32, ipx_interface *, unsigned char *);

static int ipxitf_add_local_route(ipx_interface *intrfc)
{
        return ipxrtr_add_route(intrfc->if_netnum, intrfc, NULL);
}

static const char * ipx_frame_name(unsigned short);
static const char * ipx_device_name(ipx_interface *);
static void ipxitf_discover_netnum(ipx_interface *intrfc, struct sk_buff *skb);
static int ipxitf_pprop(ipx_interface *intrfc, struct sk_buff *skb);

static int ipxitf_rcv(ipx_interface *intrfc, struct sk_buff *skb)
{
        struct ipxhdr   *ipx = skb->nh.ipxh;
        int ret = 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) {
                ret = ipxitf_pprop(intrfc, skb);
                if (ret)
                        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)
                                ret = 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)) {
                ret = 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 ret;
}

static void ipxitf_discover_netnum(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) {
                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) htonl(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(ipx_interface *intrfc, struct sk_buff *skb)
{
        struct ipxhdr *ipx = skb->nh.ipxh;
        int i, ret = -EINVAL;
        ipx_interface *ifcs;
        char *c;
        u32 *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? */
        ret = 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 = (u32 *) 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);
        for (ifcs = ipx_interfaces; ifcs; ifcs = ifcs->if_next) {
                /* Except unconfigured interfaces */
                if (!ifcs->if_netnum)
                        continue;
                                        
                /* That aren't in the list */
                if (ifcs == intrfc)
                        continue;
                l = (__u32 *) 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 ret;
}

static void ipxitf_insert(ipx_interface *intrfc)
{
        intrfc->if_next = NULL;
        spin_lock_bh(&ipx_interfaces_lock);
        if (!ipx_interfaces)
                ipx_interfaces = intrfc;
        else {
                ipx_interface *i = ipx_interfaces;
                while (i->if_next)
                        i = i->if_next;
                i->if_next = intrfc;
        }
        spin_unlock_bh(&ipx_interfaces_lock);

        if (ipxcfg_auto_select_primary && !ipx_primary_net)
                ipx_primary_net = intrfc;
}

static ipx_interface *ipxitf_alloc(struct net_device *dev, __u32 netnum,
                                   unsigned short dlink_type,
                                   struct datalink_proto *dlink,
                                   unsigned char internal, int ipx_offset)
{
        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;
                intrfc->if_sklist       = NULL;
                atomic_set(&intrfc->refcnt, 1);
                spin_lock_init(&intrfc->if_sklist_lock);
                MOD_INC_USE_COUNT;

        }

        return intrfc;
}

static int ipxitf_create_internal(ipx_interface_definition *idef)
{
        ipx_interface *intrfc;
        int ret = -EEXIST;

        /* Only one primary network allowed */
        if (ipx_primary_net)
                goto out;

        /* Must have a valid network number */
        ret = -EADDRNOTAVAIL;
        if (!idef->ipx_network)
                goto out;
        intrfc = ipxitf_find_using_net(idef->ipx_network);
        ret = -EADDRINUSE;
        if (intrfc) {
                ipxitf_put(intrfc);
                goto out;
        }
        intrfc = ipxitf_alloc(NULL, idef->ipx_network, 0, NULL, 1, 0);
        ret = -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);

        ret = ipxitf_add_local_route(intrfc);
        ipxitf_put(intrfc);
out:    return ret;
}

static int ipx_map_frame_type(unsigned char type)
{
        int ret = 0;

        switch (type) {
                case IPX_FRAME_ETHERII:
                        ret = __constant_htons(ETH_P_IPX);
                        break;
                case IPX_FRAME_8022:
                        ret = __constant_htons(ETH_P_802_2);
                        break;
                case IPX_FRAME_SNAP:
                        ret = __constant_htons(ETH_P_SNAP);
                        break;
                case IPX_FRAME_8023:
                        ret = __constant_htons(ETH_P_802_3);
                        break;
        }

        return ret;
}

static int ipxitf_create(ipx_interface_definition *idef)
{
        struct net_device *dev;
        unsigned short dlink_type = 0;
        struct datalink_proto *datalink = NULL;
        ipx_interface *intrfc;
        int err;

        if (idef->ipx_special == IPX_INTERNAL) {
                err = ipxitf_create_internal(idef);
                goto out;
        }

        err = -EEXIST;
        if (idef->ipx_special == IPX_PRIMARY && ipx_primary_net)
                goto out;

        intrfc = ipxitf_find_using_net(idef->ipx_network);
        err = -EADDRINUSE;
        if (idef->ipx_network && intrfc) {
                ipxitf_put(intrfc);
                goto out;
        }

        if (intrfc)
                ipxitf_put(intrfc);

        dev = dev_get_by_name(idef->ipx_device);
        err = -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      = __constant_htons(ETH_P_802_2);
                        datalink        = p8022_datalink;
                        break;
                case IPX_FRAME_ETHERII:
                        if (dev->type != ARPHRD_IEEE802) {
                                dlink_type      = __constant_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      = __constant_htons(ETH_P_SNAP);
                        datalink        = pSNAP_datalink;
                        break;
                case IPX_FRAME_8023:
                        dlink_type      = __constant_htons(ETH_P_802_3);
                        datalink        = p8023_datalink;
                        break;
                case IPX_FRAME_NONE:
                default:
                        err = -EPROTONOSUPPORT;
                        goto out_dev;
        }

        err = -ENETDOWN;
        if (!(dev->flags & IFF_UP))
                goto out_dev;

        /* Check addresses are suitable */
        err = -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);
                err = -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 */
        err = 0;
        if (!intrfc->if_netnum)
                goto out_intrfc;

        err = ipxitf_add_local_route(intrfc);
out_intrfc:
        ipxitf_put(intrfc);
        goto out;
out_dev:
        dev_put(dev);
out:    return err;
}

static int ipxitf_delete(ipx_interface_definition *idef)
{
        struct net_device *dev = NULL;
        unsigned short dlink_type = 0;
        ipx_interface *intrfc;
        int ret = 0;

        spin_lock_bh(&ipx_interfaces_lock);
        if (idef->ipx_special == IPX_INTERNAL) {
                if (ipx_internal_net) {
                        __ipxitf_put(ipx_internal_net);
                        goto out;
                }
                ret = -ENOENT;
                goto out;
        }

        dlink_type = ipx_map_frame_type(idef->ipx_dlink_type);
        ret = -EPROTONOSUPPORT;
        if (!dlink_type)
                goto out;

        dev = __dev_get_by_name(idef->ipx_device);
        ret = -ENODEV;
        if (!dev)
                goto out;

        intrfc = __ipxitf_find_using_phys(dev, dlink_type);
        ret = -EINVAL;
        if (!intrfc)
                goto out;
        __ipxitf_put(intrfc);

        ret = 0;
out:    spin_unlock_bh(&ipx_interfaces_lock);
        return ret;
}

static ipx_interface *ipxitf_auto_create(struct net_device *dev, 
                                         unsigned short dlink_type)
{
        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 (htons(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 *arg)
{
        struct ifreq ifr;
        int val;

        switch (cmd) {
                case SIOCSIFADDR: {
                        struct sockaddr_ipx *sipx;
                        ipx_interface_definition f;

                        if (copy_from_user(&ifr, arg, sizeof(ifr)))
                                return -EFAULT;

                        sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
                        if (sipx->sipx_family != AF_IPX)
                                return -EINVAL;

                        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)
                                return ipxitf_delete(&f);
                        else
                                return ipxitf_create(&f);
                }

                case SIOCGIFADDR: {
                        int err = 0;
                        struct sockaddr_ipx *sipx;
                        ipx_interface *ipxif;
                        struct net_device *dev;

                        if (copy_from_user(&ifr, arg, sizeof(ifr)))
                                return -EFAULT;

                        sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
                        dev = __dev_get_by_name(ifr.ifr_name);
                        if (!dev)
                                return -ENODEV;

                        ipxif = ipxitf_find_using_phys(dev, ipx_map_frame_type(sipx->sipx_type));
                        if (!ipxif)
                                return -EADDRNOTAVAIL;

                        sipx->sipx_family       = AF_IPX;
                        sipx->sipx_network      = ipxif->if_netnum;
                        memcpy(sipx->sipx_node, ipxif->if_node,
                                sizeof(sipx->sipx_node));
                        if (copy_to_user(arg, &ifr, sizeof(ifr)))
                                err = -EFAULT;

                        ipxitf_put(ipxif);
                        return err;
                }

                case SIOCAIPXITFCRT: 
                        if (get_user(val, (unsigned char *) arg))
                                return -EFAULT;
                        ipxcfg_set_auto_create(val);
                        break;

                case SIOCAIPXPRISLT: 
                        if (get_user(val, (unsigned char *) arg))
                                return -EFAULT;
                        ipxcfg_set_auto_select(val);
                        break;

                default:
                        return -EINVAL;
        }

        return 0;
}

/* Routing tables for the IPX socket layer. */

static inline void ipxrtr_hold(ipx_route *rt)
{
        atomic_inc(&rt->refcnt);
}

static inline void ipxrtr_put(ipx_route *rt)
{
        if (atomic_dec_and_test(&rt->refcnt))
                kfree(rt);
}

static ipx_route *ipxrtr_lookup(__u32 net)
{
        ipx_route *r;

        read_lock_bh(&ipx_routes_lock);
        for (r = ipx_routes; r && r->ir_net != net; r = r->ir_next)
                ;
        if (r)
                ipxrtr_hold(r);
        read_unlock_bh(&ipx_routes_lock);

        return r;
}

/* caller must hold a reference to intrfc */

static int ipxrtr_add_route(__u32 network, ipx_interface *intrfc,
                                unsigned char *node)
{
        ipx_route *rt;
        int ret;

        /* Get a route structure; either existing or create */
        rt = ipxrtr_lookup(network);
        if (!rt) {
                rt = kmalloc(sizeof(ipx_route), GFP_ATOMIC);
                ret = -EAGAIN;
                if (!rt)
                        goto out;

                atomic_set(&rt->refcnt, 1);
                ipxrtr_hold(rt);
                write_lock_bh(&ipx_routes_lock);
                rt->ir_next     = ipx_routes;
                ipx_routes      = rt;
                write_unlock_bh(&ipx_routes_lock);
        } else {
                ret = -EEXIST;
                if (intrfc == ipx_internal_net)
                        goto out_put;
        }

        rt->ir_net      = network;
        rt->ir_intrfc   = intrfc;
        if (!node) {
                memset(rt->ir_router_node, '\0', IPX_NODE_LEN);
                rt->ir_routed = 0;
        } else {
                memcpy(rt->ir_router_node, node, IPX_NODE_LEN);
                rt->ir_routed = 1;
        }

        ret = 0;
out_put:
        ipxrtr_put(rt);
out:    return ret;
}

static void ipxrtr_del_routes(ipx_interface *intrfc)
{
        ipx_route **r, *tmp;

        write_lock_bh(&ipx_routes_lock);
        for (r = &ipx_routes; (tmp = *r) != NULL;) {
                if (tmp->ir_intrfc == intrfc) {
                        *r = tmp->ir_next;
                        ipxrtr_put(tmp);
                } else
                        r = &(tmp->ir_next);
        }
        write_unlock_bh(&ipx_routes_lock);
}

static int ipxrtr_create(ipx_route_definition *rd)
{
        ipx_interface *intrfc;
        int ret = -ENETUNREACH;

        /* Find the appropriate interface */
        intrfc = ipxitf_find_using_net(rd->ipx_router_network);
        if (!intrfc)
                goto out;
        ret = ipxrtr_add_route(rd->ipx_network, intrfc, rd->ipx_router_node);
        ipxitf_put(intrfc);
out:    return ret;
}

static int ipxrtr_delete(long net)
{
        ipx_route **r;
        ipx_route *tmp;
        int err;

        write_lock_bh(&ipx_routes_lock);
        for (r = &ipx_routes; (tmp = *r) != NULL;) {
                if (tmp->ir_net == net) {
                        /* Directly connected; can't lose route */
                        err = -EPERM;
                        if (!tmp->ir_routed)
                                goto out;

                        *r = tmp->ir_next;
                        ipxrtr_put(tmp);
                        err = 0;
                        goto out;
                }

                r = &(tmp->ir_next);
        }
        err = -ENOENT;
out:    write_unlock_bh(&ipx_routes_lock);
        return err;
}

/*
 *      Checksum routine for IPX
 */
 
/* Note: We assume ipx_tctrl==0 and htons(length)==ipx_pktsize */
/* This functions should *not* mess with packet contents */

static __u16 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.)
         */
        /* start at ipx_dest - We skip the checksum field and start with
         * ipx_type before the loop, not considering ipx_tctrl in the calc */
        __u16 *p = (__u16 *)&packet->ipx_dest;
        __u32 i = (length >> 1) - 1; /* Number of complete words */
        __u32 sum = packet->ipx_type << sizeof(packet->ipx_tctrl); 

        /* Loop through all complete words except the checksum field,
         * ipx_type (accounted above) and ipx_tctrl (not used in the cksum) */
        while (--i)
                sum += *p++;

        /* Add on the last part word if it exists */
        if (packet->ipx_pktsize & __constant_htons(1))
                sum += ntohs(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++;

        return ~sum;
}

/*
 * Route an outgoing frame from a socket.
 */
static int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
                                struct iovec *iov, int len, int noblock)
{
        struct sk_buff *skb;
        ipx_interface *intrfc;
        struct ipxhdr *ipx;
        int size;
        int ipx_offset;
        ipx_route *rt = NULL;
        int err;

        /* Find the appropriate interface on which to send packet */
        if (!usipx->sipx_network && ipx_primary_net) {
                usipx->sipx_network = ipx_primary_net->if_netnum;
                intrfc = ipx_primary_net;
        } else {
                rt = ipxrtr_lookup(usipx->sipx_network);
                err = -ENETUNREACH;
                if (!rt)
                        goto out;
                intrfc = rt->ir_intrfc;
        }

        ipxitf_hold(intrfc);
        ipx_offset = intrfc->if_ipx_offset;
        size = sizeof(struct ipxhdr) + len + ipx_offset;

        skb = sock_alloc_send_skb(sk, size, noblock, &err);
        if (!skb)
                goto out_put;

        skb_reserve(skb, ipx_offset);
        skb->sk = sk;

        /* Fill in IPX header */
        ipx = (struct ipxhdr *)skb_put(skb, sizeof(struct ipxhdr));
        ipx->ipx_pktsize = htons(len + sizeof(struct ipxhdr));
        IPX_SKB_CB(skb)->ipx_tctrl = 0;
        ipx->ipx_type    = usipx->sipx_type;
        skb->h.raw       = (void *)skb->nh.ipxh = ipx;

        IPX_SKB_CB(skb)->last_hop.index = -1;
#ifdef CONFIG_IPX_INTERN
        IPX_SKB_CB(skb)->ipx_source_net = sk->protinfo.af_ipx.intrfc->if_netnum;
        memcpy(ipx->ipx_source.node, sk->protinfo.af_ipx.node, IPX_NODE_LEN);
#else
        err = ntohs(sk->protinfo.af_ipx.port);
        if (err == 0x453 || err == 0x452) {
                /* RIP/SAP special handling for mars_nwe */
                IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;
                memcpy(ipx->ipx_source.node, intrfc->if_node, IPX_NODE_LEN);
        } else {
                IPX_SKB_CB(skb)->ipx_source_net =
                                        sk->protinfo.af_ipx.intrfc->if_netnum;
                memcpy(ipx->ipx_source.node, sk->protinfo.af_ipx.intrfc->if_node, IPX_NODE_LEN);
        }
#endif  /* CONFIG_IPX_INTERN */
        ipx->ipx_source.sock            = sk->protinfo.af_ipx.port;
        IPX_SKB_CB(skb)->ipx_dest_net   = usipx->sipx_network;
        memcpy(ipx->ipx_dest.node, usipx->sipx_node, IPX_NODE_LEN);
        ipx->ipx_dest.sock              = usipx->sipx_port;

        err = memcpy_fromiovec(skb_put(skb, len), iov, len);
        if (err) {
                kfree_skb(skb);
                goto out_put;
        }       

        /* Apply checksum. Not allowed on 802.3 links. */
        if (sk->no_check || intrfc->if_dlink_type == IPX_FRAME_8023)
                ipx->ipx_checksum = 0xFFFF;
        else
                ipx->ipx_checksum = ipx_cksum(ipx, len + sizeof(struct ipxhdr));

        err = ipxitf_send(intrfc, skb, (rt && rt->ir_routed) ? 
                                rt->ir_router_node : ipx->ipx_dest.node);
out_put:
        ipxitf_put(intrfc);
        if (rt)
                ipxrtr_put(rt);
out:    return err;
}

/* the skb has to be unshared, we'll end up calling ipxitf_send, that'll
 * modify the packet */
int ipxrtr_route_skb(struct sk_buff *skb)
{
        struct ipxhdr *ipx = skb->nh.ipxh;
        ipx_route *r = ipxrtr_lookup(IPX_SKB_CB(skb)->ipx_dest_net);

        if (!r) {       /* no known route */
                kfree_skb(skb);
                return 0;
        }

        ipxitf_hold(r->ir_intrfc);
        ipxitf_send(r->ir_intrfc, skb, r->ir_routed ?
                        r->ir_router_node : ipx->ipx_dest.node);
        ipxitf_put(r->ir_intrfc);
        ipxrtr_put(r);

        return 0;
}

/*
 * We use a normal struct rtentry for route handling
 */
static int ipxrtr_ioctl(unsigned int cmd, void *arg)
{
        struct rtentry rt;      /* Use these to behave like 'other' stacks */
        struct sockaddr_ipx *sg, *st;
        int ret = -EFAULT;

        if (copy_from_user(&rt, arg, sizeof(rt)))
                goto out;

        sg = (struct sockaddr_ipx *)&rt.rt_gateway;
        st = (struct sockaddr_ipx *)&rt.rt_dst;

        ret = -EINVAL;
        if (!(rt.rt_flags & RTF_GATEWAY) || /* Direct routes are fixed */
            sg->sipx_family != AF_IPX ||
            st->sipx_family != AF_IPX)
                goto out;

        switch (cmd) {
                case SIOCDELRT:
                        ret = ipxrtr_delete(st->sipx_network);
                        break;
                case SIOCADDRT: {
                        struct ipx_route_definition f;
                        f.ipx_network           = st->sipx_network;
                        f.ipx_router_network    = sg->sipx_network;
                        memcpy(f.ipx_router_node, sg->sipx_node, IPX_NODE_LEN);
                        ret = ipxrtr_create(&f);
                        break;
                }
        }

out:    return ret;
}

static const char *ipx_frame_name(unsigned short frame)
{
        char* ret = "None";

        switch (ntohs(frame)) {
                case ETH_P_IPX:         ret = "EtherII";        break;
                case ETH_P_802_2:       ret = "802.2";          break;
                case ETH_P_SNAP:        ret = "SNAP";           break;
                case ETH_P_802_3:       ret = "802.3";          break;
                case ETH_P_TR_802_2:    ret = "802.2TR";        break;
        }

        return ret;
}

static const char *ipx_device_name(ipx_interface *intrfc)
{
        return intrfc->if_internal ? "Internal" :
                intrfc->if_dev ? intrfc->if_dev->name : "Unknown";
}

/* Called from proc fs */
static int ipx_interface_get_info(char *buffer, char **start, off_t offset,
                                  int length)
{
        ipx_interface *i;
        off_t begin = 0, pos = 0;
        int len = 0;

        /* Theory.. Keep printing in the same place until we pass offset */

        len += sprintf(buffer, "%-11s%-15s%-9s%-11s%s", "Network",
                "Node_Address", "Primary", "Device", "Frame_Type");
#ifdef IPX_REFCNT_DEBUG
        len += sprintf(buffer + len, "  refcnt");
#endif
        strcat(buffer + len++, "\n");
        spin_lock_bh(&ipx_interfaces_lock);
        for (i = ipx_interfaces; i; i = i->if_next) {
                len += sprintf(buffer + len, "%08lX   ",
                                (long unsigned int) ntohl(i->if_netnum));
                len += sprintf(buffer + len, "%02X%02X%02X%02X%02X%02X   ",
                                i->if_node[0], i->if_node[1], i->if_node[2],
                                i->if_node[3], i->if_node[4], i->if_node[5]);
                len += sprintf(buffer + len, "%-9s", i == ipx_primary_net ?
                        "Yes" : "No");
                len += sprintf(buffer + len, "%-11s", ipx_device_name(i));
                len += sprintf(buffer + len, "%-9s",
                        ipx_frame_name(i->if_dlink_type));
#ifdef IPX_REFCNT_DEBUG
                len += sprintf(buffer + len, "%6d", atomic_read(&i->refcnt));
#endif
                strcat(buffer + len++, "\n");
                /* Are we still dumping unwanted data then discard the record */
                pos = begin + len;

                if (pos < offset) {
                        len   = 0;      /* Keep dumping into the buffer start */
                        begin = pos;
                }
                if (pos > offset + length)      /* We have dumped enough */
                        break;
        }
        spin_unlock_bh(&ipx_interfaces_lock);

        /* The data in question runs from begin to begin+len */
        *start = buffer + (offset - begin);     /* Start of wanted data */
        len -= (offset - begin); /* Remove unwanted header data from length */
        if (len > length)
                len = length;   /* Remove unwanted tail data from length */

        return len;
}

static int ipx_get_info(char *buffer, char **start, off_t offset, int length)
{
        struct sock *s;
        ipx_interface *i;
        off_t begin = 0, pos = 0;
        int len = 0;

        /* Theory.. Keep printing in the same place until we pass offset */

#ifdef CONFIG_IPX_INTERN
        len += sprintf(buffer, "%-28s%-28s%-10s%-10s%-7s%s\n", "Local_Address",
#else
        len += sprintf(buffer, "%-15s%-28s%-10s%-10s%-7s%s\n", "Local_Address",
#endif  /* CONFIG_IPX_INTERN */
                        "Remote_Address", "Tx_Queue", "Rx_Queue",
                        "State", "Uid");

        spin_lock_bh(&ipx_interfaces_lock);
        for (i = ipx_interfaces; i; i = i->if_next) {
                ipxitf_hold(i);
                spin_lock_bh(&i->if_sklist_lock);
                for (s = i->if_sklist; s; s = s->next) {
#ifdef CONFIG_IPX_INTERN
                        len += sprintf(buffer + len,
                                       "%08lX:%02X%02X%02X%02X%02X%02X:%04X  ",
                                       (unsigned long) htonl(s->protinfo.af_ipx.intrfc->if_netnum),
                                       s->protinfo.af_ipx.node[0],
                                       s->protinfo.af_ipx.node[1],
                                       s->protinfo.af_ipx.node[2],
                                       s->protinfo.af_ipx.node[3],
                                       s->protinfo.af_ipx.node[4],
                                       s->protinfo.af_ipx.node[5],
                                       htons(s->protinfo.af_ipx.port));
#else
                        len += sprintf(buffer + len, "%08lX:%04X  ",
                                       (unsigned long) htonl(i->if_netnum),
                                       htons(s->protinfo.af_ipx.port));
#endif  /* CONFIG_IPX_INTERN */
                        if (s->state != TCP_ESTABLISHED)
                                len += sprintf(buffer + len, "%-28s",
                                                "Not_Connected");
                        else {
                                len += sprintf(buffer + len,
                                        "%08lX:%02X%02X%02X%02X%02X%02X:%04X  ",
                                        (unsigned long) htonl(s->protinfo.af_ipx.dest_addr.net),
                                        s->protinfo.af_ipx.dest_addr.node[0],
                                        s->protinfo.af_ipx.dest_addr.node[1],
                                        s->protinfo.af_ipx.dest_addr.node[2],
                                        s->protinfo.af_ipx.dest_addr.node[3],
                                        s->protinfo.af_ipx.dest_addr.node[4],
                                        s->protinfo.af_ipx.dest_addr.node[5],
                                        htons(s->protinfo.af_ipx.dest_addr.sock));
                        }

                        len += sprintf(buffer + len, "%08X  %08X  ",
                                atomic_read(&s->wmem_alloc),
                                atomic_read(&s->rmem_alloc));
                        len += sprintf(buffer + len, "%02X     %03d\n",
                                s->state, SOCK_INODE(s->socket)->i_uid);

                        pos = begin + len;
                        if (pos < offset) {
                                len   = 0;
                                begin = pos;
                        }

                        if (pos > offset + length)  /* We have dumped enough */
                                break;
                }
                spin_unlock_bh(&i->if_sklist_lock);
                ipxitf_put(i);
        }
        spin_unlock_bh(&ipx_interfaces_lock);

        /* The data in question runs from begin to begin+len */
        *start = buffer + offset - begin;
        len -= (offset - begin);
        if (len > length)
                len = length;

        return len;
}

static int ipx_rt_get_info(char *buffer, char **start, off_t offset, int length)
{
        ipx_route *rt;
        off_t begin = 0, pos = 0;
        int len = 0;

        len += sprintf(buffer, "%-11s%-13s%s\n",
                        "Network", "Router_Net", "Router_Node");
        read_lock_bh(&ipx_routes_lock);
        for (rt = ipx_routes; rt; rt = rt->ir_next) {
                len += sprintf(buffer + len, "%08lX   ",
                                (long unsigned int) ntohl(rt->ir_net));
                if (rt->ir_routed) {
                        len += sprintf(buffer + len,
                                        "%08lX     %02X%02X%02X%02X%02X%02X\n",
                        (long unsigned int) ntohl(rt->ir_intrfc->if_netnum),
                                rt->ir_router_node[0], rt->ir_router_node[1],
                                rt->ir_router_node[2], rt->ir_router_node[3],
                                rt->ir_router_node[4], rt->ir_router_node[5]);
                } else {
                        len += sprintf(buffer + len, "%-13s%s\n",
                                        "Directly", "Connected");
                }

                pos = begin + len;
                if (pos < offset) {
                        len = 0;
                        begin = pos;
                }

                if (pos > offset + length)
                        break;
        }
        read_unlock_bh(&ipx_routes_lock);

        *start = buffer + (offset - begin);
        len -= (offset - begin);
        if (len > length)
                len = length;

        return len;
}

/* 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 *optval, int optlen)
{
        struct sock *sk = sock->sk;
        int opt;
        int ret = -EINVAL;

        if (optlen != sizeof(int))
                goto out;

        ret = -EFAULT;
        if (get_user(opt, (unsigned int *)optval))
                goto out;

        ret = -ENOPROTOOPT;
        if (!(level == SOL_IPX && optname == IPX_TYPE))
                goto out;

        sk->protinfo.af_ipx.type = opt;
        ret = 0;
out:    return ret;
}

static int ipx_getsockopt(struct socket *sock, int level, int optname,
        char *optval, int *optlen)
{
        struct sock *sk = sock->sk;
        int val = 0;
        int len;
        int ret = -ENOPROTOOPT;

        if (!(level == SOL_IPX && optname == IPX_TYPE))
                goto out;

        val = sk->protinfo.af_ipx.type;

        ret = -EFAULT;
        if (get_user(len, optlen))
                goto out;

        len = min_t(unsigned int, len, sizeof(int));
        ret = -EINVAL;
        if(len < 0)
                goto out;
                
        ret = -EFAULT;
        if (put_user(len, optlen) || copy_to_user(optval, &val, len))
                goto out;

        ret = 0;
out:    return ret;
}

static int ipx_create(struct socket *sock, int protocol)
{
        int ret = -ESOCKTNOSUPPORT;
        struct sock *sk;

        switch (sock->type) {
                case SOCK_DGRAM:
                        sk = sk_alloc(PF_IPX, GFP_KERNEL, 1);
                        ret = -ENOMEM;
                        if (!sk)
                                goto out;
                        sock->ops = &ipx_dgram_ops;
                        break;

                case SOCK_SEQPACKET:
                        /*
                         * From this point on SPX sockets are handled
                         * by af_spx.c and the methods replaced.
                         */
                        if (spx_family_ops) {
                                ret = spx_family_ops->create(sock, protocol);
                                goto out;
                        }
                        /* Fall through if SPX is not loaded */
                case SOCK_STREAM:       /* Allow higher levels to piggyback */
                default:
                        goto out;
        }
#ifdef IPX_REFCNT_DEBUG
        atomic_inc(&ipx_sock_nr);
        printk(KERN_DEBUG "IPX socket %p created, now we have %d alive\n", sk,
                        atomic_read(&ipx_sock_nr));
#endif
        sock_init_data(sock, sk);
        sk->destruct    = NULL;
        sk->no_check    = 1;            /* Checksum off by default */

        MOD_INC_USE_COUNT;
        ret = 0;
out:    return ret;
}

static int ipx_release(struct socket *sock)
{
        struct sock *sk = sock->sk;

        if (!sk)
                goto out;

        if (!sk->dead)
                sk->state_change(sk);

        sk->dead = 1;
        sock->sk = NULL;
        ipx_destroy_socket(sk);

        if (sock->type == SOCK_DGRAM)
                MOD_DEC_USE_COUNT;

out:    return 0;
}

/* caller must hold a reference to intrfc */

static unsigned short ipx_first_free_socketnum(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, ntohs(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 ntohs(socketNum);
}

static int ipx_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
        struct sock *sk = sock->sk;
        ipx_interface *intrfc;
        struct sockaddr_ipx *addr = (struct sockaddr_ipx *)uaddr;
        int ret = -EINVAL;

        if (!sk->zapped || addr_len != sizeof(struct sockaddr_ipx))
                goto out;

        intrfc = ipxitf_find_using_net(addr->sipx_network);
        ret = -EADDRNOTAVAIL;
        if (!intrfc)
                goto out;

        if (!addr->sipx_port) {
                addr->sipx_port = ipx_first_free_socketnum(intrfc);
                ret = -EINVAL;
                if (!addr->sipx_port)
                        goto out_put;
        }

        /* protect IPX system stuff like routing/sap */
        ret = -EACCES;
        if (ntohs(addr->sipx_port) < IPX_MIN_EPHEMERAL_SOCKET &&
            !capable(CAP_NET_ADMIN))
                goto out_put;

        sk->protinfo.af_ipx.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.
                 */

                ret = -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(sk->protinfo.af_ipx.node, intrfc->if_node,
                               IPX_NODE_LEN);
                else
                        memcpy(sk->protinfo.af_ipx.node, addr->sipx_node,
                                IPX_NODE_LEN);

                ret = -EADDRINUSE;
                if (ipxitf_find_internal_socket(intrfc,
                                                sk->protinfo.af_ipx.node,
                                                sk->protinfo.af_ipx.port)) {
                        SOCK_DEBUG(sk,
                                "IPX: bind failed because port %X in use.\n",
                                ntohs((int)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(sk->protinfo.af_ipx.node, intrfc->if_node,
                        IPX_NODE_LEN);

                ret = -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;
                }
        }

#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() */

        ret = -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);
        sk->zapped = 0;
        SOCK_DEBUG(sk, "IPX: bound socket 0x%04X.\n", ntohs(addr->sipx_port) );

        ret = 0;
out_put:
        ipxitf_put(intrfc);
out:    return ret;
}

static int ipx_connect(struct socket *sock, struct sockaddr *uaddr,
        int addr_len, int flags)
{
        struct sock *sk = sock->sk;
        struct sockaddr_ipx *addr;
        int ret = -EINVAL;
        ipx_route *rt;

        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 (!sk->protinfo.af_ipx.port) {
                struct sockaddr_ipx uaddr;

                uaddr.sipx_port         = 0;
                uaddr.sipx_network      = 0;

#ifdef CONFIG_IPX_INTERN
                ret = -ENETDOWN;
                if (!sk->protinfo.af_ipx.intrfc)
                        goto out; /* Someone zonked the iface */
                memcpy(uaddr.sipx_node, sk->protinfo.af_ipx.intrfc->if_node,
                        IPX_NODE_LEN);
#endif  /* CONFIG_IPX_INTERN */

                ret = ipx_bind(sock, (struct sockaddr *)&uaddr,
                                sizeof(struct sockaddr_ipx));
                if (ret)
                        goto out;
        }

        /* We can either connect to primary network or somewhere
         * we can route to */
        rt = ipxrtr_lookup(addr->sipx_network);
        ret = -ENETUNREACH;
        if (!rt && !(!addr->sipx_network && ipx_primary_net))
                goto out;

        sk->protinfo.af_ipx.dest_addr.net  = addr->sipx_network;
        sk->protinfo.af_ipx.dest_addr.sock = addr->sipx_port;
        memcpy(sk->protinfo.af_ipx.dest_addr.node,
                addr->sipx_node, IPX_NODE_LEN);
        sk->protinfo.af_ipx.type = addr->sipx_type;

        if (sock->type == SOCK_DGRAM) {
                sock->state     = SS_CONNECTED;
                sk->state       = TCP_ESTABLISHED;
        }

        if (rt)
                ipxrtr_put(rt);
        ret = 0;
out:    return ret;
}


static int ipx_getname(struct socket *sock, struct sockaddr *uaddr,
                        int *uaddr_len, int peer)
{
        ipx_address *addr;
        struct sockaddr_ipx sipx;
        struct sock *sk = sock->sk;
        int ret;

        *uaddr_len = sizeof(struct sockaddr_ipx);

        if (peer) {
                ret = -ENOTCONN;
                if (sk->state != TCP_ESTABLISHED)
                        goto out;

                addr = &sk->protinfo.af_ipx.dest_addr;
                sipx.sipx_network       = addr->net;
                sipx.sipx_port          = addr->sock;
                memcpy(sipx.sipx_node, addr->node, IPX_NODE_LEN);
        } else {
                if (sk->protinfo.af_ipx.intrfc) {
                        sipx.sipx_network =
                                sk->protinfo.af_ipx.intrfc->if_netnum;
#ifdef CONFIG_IPX_INTERN
                        memcpy(sipx.sipx_node, sk->protinfo.af_ipx.node,
                                IPX_NODE_LEN);
#else
                        memcpy(sipx.sipx_node,
                                sk->protinfo.af_ipx.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 = sk->protinfo.af_ipx.port;
        }

        sipx.sipx_family = AF_IPX;
        sipx.sipx_type   = sk->protinfo.af_ipx.type;
        memcpy(uaddr, &sipx, sizeof(sipx));

        ret = 0;
out:    return ret;
}

int ipx_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
{
        /* NULL here for pt means the packet was looped back */
        ipx_interface *intrfc;
        struct ipxhdr *ipx;
        u16 ipx_pktsize;
        int ret = 0;
                
        /* Not ours */  
        if (skb->pkt_type == PACKET_OTHERHOST)
                goto drop;

        if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
                goto out;

        ipx             = skb->nh.ipxh;
        ipx_pktsize     = ntohs(ipx->ipx_pktsize);
        
        /* Too small or invalid header? */
        if (ipx_pktsize < sizeof(struct ipxhdr) || ipx_pktsize > skb->len)
                goto drop;
                        
        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 &&
                   ntohl(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;
        }

        ret = ipxitf_rcv(intrfc, skb);
        ipxitf_put(intrfc);
        goto out;
drop:   kfree_skb(skb);
out:    return ret;
}

static int ipx_sendmsg(struct socket *sock, struct msghdr *msg, int len,
        struct scm_cookie *scm)
{
        struct sock *sk = sock->sk;
        struct sockaddr_ipx *usipx = (struct sockaddr_ipx *)msg->msg_name;
        struct sockaddr_ipx local_sipx;
        int ret = -EINVAL;
        int flags = msg->msg_flags;

        /* Socket gets bound below anyway */
/*      if (sk->zapped)
                return -EIO; */ /* Socket not bound */
        if (flags & ~MSG_DONTWAIT)
                goto out;

        if (usipx) {
                if (!sk->protinfo.af_ipx.port) {
                        struct sockaddr_ipx uaddr;

                        uaddr.sipx_port         = 0;
                        uaddr.sipx_network      = 0;
#ifdef CONFIG_IPX_INTERN
                        ret = -ENETDOWN;
                        if (!sk->protinfo.af_ipx.intrfc)
                                goto out; /* Someone zonked the iface */
                        memcpy(uaddr.sipx_node,
                                sk->protinfo.af_ipx.intrfc->if_node,
                                IPX_NODE_LEN);
#endif
                        ret = ipx_bind(sock, (struct sockaddr *)&uaddr,
                                        sizeof(struct sockaddr_ipx));
                        if (ret)
                                goto out;
                }

                ret = -EINVAL;
                if (msg->msg_namelen < sizeof(*usipx) ||
                    usipx->sipx_family != AF_IPX)
                        goto out;
        } else {
                ret = -ENOTCONN;
                if (sk->state != TCP_ESTABLISHED)
                        goto out;

                usipx = &local_sipx;
                usipx->sipx_family      = AF_IPX;
                usipx->sipx_type        = sk->protinfo.af_ipx.type;
                usipx->sipx_port        = sk->protinfo.af_ipx.dest_addr.sock;
                usipx->sipx_network     = sk->protinfo.af_ipx.dest_addr.net;
                memcpy(usipx->sipx_node, sk->protinfo.af_ipx.dest_addr.node,
                                IPX_NODE_LEN);
        }

        ret = ipxrtr_route_packet(sk, usipx, msg->msg_iov, len,
                                     flags & MSG_DONTWAIT);
        if (ret >= 0)
                ret = len;
out:    return ret;
}


static int ipx_recvmsg(struct socket *sock, struct msghdr *msg, int size,
                int flags, struct scm_cookie *scm)
{
        struct sock *sk = sock->sk;
        struct sockaddr_ipx *sipx = (struct sockaddr_ipx *)msg->msg_name;
        struct ipxhdr *ipx = NULL;
        struct sk_buff *skb;
        int copied, err;

        /* put the autobinding in */
        if (!sk->protinfo.af_ipx.port) {
                struct sockaddr_ipx uaddr;

                uaddr.sipx_port         = 0;
                uaddr.sipx_network      = 0;

#ifdef CONFIG_IPX_INTERN
                err = -ENETDOWN;
                if (!sk->protinfo.af_ipx.intrfc)
                        goto out; /* Someone zonked the iface */
                memcpy(uaddr.sipx_node,
                        sk->protinfo.af_ipx.intrfc->if_node, IPX_NODE_LEN);
#endif  /* CONFIG_IPX_INTERN */

                err = ipx_bind(sock, (struct sockaddr *)&uaddr,
                                sizeof(struct sockaddr_ipx));
                if (err)
                        goto out;
        }
        
        err = -ENOTCONN;
        if (sk->zapped)
                goto out;

        skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
                                        flags & MSG_DONTWAIT, &err);
        if (!skb)
                goto out;

        ipx     = skb->nh.ipxh;
        copied  = ntohs(ipx->ipx_pktsize) - sizeof(struct ipxhdr);
        if (copied > size) {
                copied = size;
                msg->msg_flags |= MSG_TRUNC;
        }

        err = skb_copy_datagram_iovec(skb, sizeof(struct ipxhdr), msg->msg_iov,
                                        copied);
        if (err)
                goto out_free;
        sk->stamp = skb->stamp;

        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;
        }
        err = copied;

out_free:
        skb_free_datagram(sk, skb);
out:    return err;
}


static int ipx_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        long amount = 0;
        struct sock *sk = sock->sk;

        switch (cmd) {
                case TIOCOUTQ:
                        amount = sk->sndbuf - atomic_read(&sk->wmem_alloc);
                        if (amount < 0)
                                amount = 0;
                        return put_user(amount, (int *)arg);

                case TIOCINQ: {
                        struct sk_buff *skb = skb_peek(&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);
                        return put_user(amount, (int *)arg);
                }

                case SIOCADDRT:
                case SIOCDELRT:
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        return ipxrtr_ioctl(cmd, (void *)arg);

                case SIOCSIFADDR:
                case SIOCAIPXITFCRT:
                case SIOCAIPXPRISLT:
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;

                case SIOCGIFADDR:
                        return ipxitf_ioctl(cmd, (void *)arg);

                case SIOCIPXCFGDATA:
                        return ipxcfg_get_config_data((void *)arg);

                case SIOCIPXNCPCONN:
                        /*
                         * This socket wants to take care of the NCP connection
                         * handed to us in arg.
                         */
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        return get_user(sk->protinfo.af_ipx.ipx_ncp_conn,
                                        (const unsigned short *)(arg));

                case SIOCGSTAMP: {
                        int ret = -EINVAL;
                        if (sk) {
                                if (!sk->stamp.tv_sec)
                                        return -ENOENT;
                                ret = -EFAULT;
                                if (!copy_to_user((void *)arg, &sk->stamp,
                                                sizeof(struct timeval)))
                                        ret = 0;
                        }

                        return ret;
                }

                case SIOCGIFDSTADDR:
                case SIOCSIFDSTADDR:
                case SIOCGIFBRDADDR:
                case SIOCSIFBRDADDR:
                case SIOCGIFNETMASK:
                case SIOCSIFNETMASK:
                        return -EINVAL;

                default:
                        return dev_ioctl(cmd,(void *) arg);
        }

        /*NOT REACHED*/
        return 0;
}

/*
 *      SPX interface support
 */

int ipx_register_spx(struct proto_ops **p, struct net_proto_family *spx)
{
        if (spx_family_ops)
                return -EBUSY;
        cli();
        MOD_INC_USE_COUNT;
        *p = &ipx_dgram_ops;
        spx_family_ops = spx;
        sti();
        return 0;
}

int ipx_unregister_spx(void)
{
        spx_family_ops = NULL;
        MOD_DEC_USE_COUNT;
        return 0;
}

/*
 * Socket family declarations
 */

static struct net_proto_family ipx_family_ops = {
        family:         PF_IPX,
        create:         ipx_create,
};

static struct proto_ops SOCKOPS_WRAPPED(ipx_dgram_ops) = {
        family:         PF_IPX,

        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,
        listen:         sock_no_listen,
        shutdown:       sock_no_shutdown, /* FIXME: have to support shutdown */
        setsockopt:     ipx_setsockopt,
        getsockopt:     ipx_getsockopt,
        sendmsg:        ipx_sendmsg,
        recvmsg:        ipx_recvmsg,
        mmap:           sock_no_mmap,
        sendpage:       sock_no_sendpage,
};

#include <linux/smp_lock.h>
SOCKOPS_WRAP(ipx_dgram, PF_IPX);

static struct packet_type ipx_8023_packet_type = {
        type:           __constant_htons(ETH_P_802_3),
        func:           ipx_rcv,
        data:           (void *) 1,     /* yap, I understand shared skbs :-) */
};

static struct packet_type ipx_dix_packet_type = {
        type:           __constant_htons(ETH_P_IPX),
        func:           ipx_rcv,
        data:           (void *) 1,     /* yap, I understand shared skbs :-) */
};

static struct notifier_block ipx_dev_notifier = {
        notifier_call:  ipxitf_device_event,
};


extern struct datalink_proto *make_EII_client(void);
extern struct datalink_proto *make_8023_client(void);
extern void destroy_EII_client(struct datalink_proto *);
extern void destroy_8023_client(struct datalink_proto *);

static unsigned char ipx_8022_type = 0xE0;
static unsigned char ipx_snap_id[5] = { 0x0, 0x0, 0x0, 0x81, 0x37 };
static char banner[] __initdata =
        KERN_INFO "NET4: Linux IPX 0.47 for NET4.0\n"
        KERN_INFO "IPX Portions Copyright (c) 1995 Caldera, Inc.\n" \
        KERN_INFO "IPX Portions Copyright (c) 2000, 2001 Conectiva, Inc.\n";

static int __init ipx_init(void)
{
        sock_register(&ipx_family_ops);

        pEII_datalink = make_EII_client();
        dev_add_pack(&ipx_dix_packet_type);

        p8023_datalink = make_8023_client();
        dev_add_pack(&ipx_8023_packet_type);

        p8022_datalink = register_8022_client(ipx_8022_type, ipx_rcv);
        if (!p8022_datalink)
                printk(KERN_CRIT "IPX: Unable to register with 802.2\n");

        pSNAP_datalink = register_snap_client(ipx_snap_id, ipx_rcv);
        if (!pSNAP_datalink)
                printk(KERN_CRIT "IPX: Unable to register with SNAP\n");

        register_netdevice_notifier(&ipx_dev_notifier);
        ipx_register_sysctl();
#ifdef CONFIG_PROC_FS
        proc_net_create("ipx", 0, ipx_get_info);
        proc_net_create("ipx_interface", 0, ipx_interface_get_info);
        proc_net_create("ipx_route", 0, ipx_rt_get_info);
#endif
        printk(banner);
        return 0;
}

module_init(ipx_init);

/* Higher layers need this info to prep tx pkts */
int ipx_if_offset(unsigned long ipx_net_number)
{
        ipx_route *rt = ipxrtr_lookup(ipx_net_number);
        int ret = -ENETUNREACH;

        if (!rt)
                goto out;
        ret = rt->ir_intrfc->if_ipx_offset;
        ipxrtr_put(rt);
out:    return ret;
}

/* Export symbols for higher layers */
EXPORT_SYMBOL(ipxrtr_route_skb);
EXPORT_SYMBOL(ipx_if_offset);
EXPORT_SYMBOL(ipx_remove_socket);
EXPORT_SYMBOL(ipx_register_spx);
EXPORT_SYMBOL(ipx_unregister_spx);

/* Note on MOD_{INC,DEC}_USE_COUNT:
 *
 * Use counts are incremented/decremented when
 * sockets are created/deleted.
 *
 * Routes are always associated with an interface, and
 * allocs/frees will remain properly accounted for by
 * their associated interfaces.
 *
 * Ergo, before the ipx module can be removed, all IPX
 * sockets be closed from user space.
 */

static void __exit ipx_proto_finito(void)
{
        /* no need to worry about having anything on the ipx_interfaces
         * list, when a interface is created we increment the module
         * usage count, so the module will only be unloaded when there
         * are no more interfaces */

        proc_net_remove("ipx_route");
        proc_net_remove("ipx_interface");
        proc_net_remove("ipx");
        ipx_unregister_sysctl();

        unregister_netdevice_notifier(&ipx_dev_notifier);

        unregister_snap_client(ipx_snap_id);
        pSNAP_datalink = NULL;

        unregister_8022_client(ipx_8022_type);
        p8022_datalink = NULL;

        dev_remove_pack(&ipx_8023_packet_type);
        destroy_8023_client(p8023_datalink);
        p8023_datalink = NULL;

        dev_remove_pack(&ipx_dix_packet_type);
        destroy_EII_client(pEII_datalink);
        pEII_datalink = NULL;

        sock_unregister(ipx_family_ops.family);
}

module_exit(ipx_proto_finito);
MODULE_LICENSE("GPL");