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ddp.c

/*
 *    DDP:  An implementation of the AppleTalk DDP protocol for
 *          Ethernet 'ELAP'.
 *
 *          Alan Cox  <Alan.Cox@linux.org>
 *
 *          With more than a little assistance from
 *
 *          Wesley Craig <netatalk@umich.edu>
 *
 *    Fixes:
 *          Neil Horman       :     Added missing device ioctls
 *          Michael Callahan  :     Made routing work
 *          Wesley Craig            :     Fix probing to listen to a
 *                                  passed node id.
 *          Alan Cox          :     Added send/recvmsg support
 *          Alan Cox          :     Moved at. to protinfo in
 *                                  socket.
 *          Alan Cox          :     Added firewall hooks.
 *          Alan Cox          :     Supports new ARPHRD_LOOPBACK
 *          Christer Weinigel :     Routing and /proc fixes.
 *          Bradford Johnson  :     LocalTalk.
 *          Tom Dyas          :     Module support.
 *          Alan Cox          :     Hooks for PPP (based on the
 *                                  LocalTalk hook).
 *          Alan Cox          :     Posix bits
 *          Alan Cox/Mike Freeman   :     Possible fix to NBP problems
 *          Bradford Johnson  :     IP-over-DDP (experimental)
 *          Jay Schulist            :     Moved IP-over-DDP to its own
 *                                  driver file. (ipddp.c & ipddp.h)
 *          Jay Schulist            :     Made work as module with
 *                                  AppleTalk drivers, cleaned it.
 *          Rob Newberry            :     Added proxy AARP and AARP
 *                                  procfs, moved probing to AARP
 *                                  module.
 *              Adrian Sun/
 *              Michael Zuelsdorff      :       fix for net.0 packets. don't
 *                                              allow illegal ether/tokentalk
 *                                              port assignment. we lose a
 *                                              valid localtalk port as a
 *                                              result.
 *          Arnaldo C. de Melo      :     Cleanup, in preparation for
 *                                  shared skb support 8)
 *          Arnaldo C. de Melo      :     Move proc stuff to atalk_proc.c,
 *                                  use seq_file
 *
 *          This program is free software; you can redistribute it and/or
 *          modify it under the terms of the GNU General Public License
 *          as published by the Free Software Foundation; either version
 *          2 of the License, or (at your option) any later version.
 *
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/termios.h>    /* For TIOCOUTQ/INQ */
#include <net/datalink.h>
#include <net/psnap.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/route.h>
#include <linux/atalk.h>
#include "../core/kmap_skb.h"

struct datalink_proto *ddp_dl, *aarp_dl;
static const struct proto_ops atalk_dgram_ops;

/**************************************************************************\
*                                                                          *
* Handlers for the socket list.                                            *
*                                                                          *
\**************************************************************************/

HLIST_HEAD(atalk_sockets);
DEFINE_RWLOCK(atalk_sockets_lock);

static inline void __atalk_insert_socket(struct sock *sk)
{
      sk_add_node(sk, &atalk_sockets);
}

static inline void atalk_remove_socket(struct sock *sk)
{
      write_lock_bh(&atalk_sockets_lock);
      sk_del_node_init(sk);
      write_unlock_bh(&atalk_sockets_lock);
}

static struct sock *atalk_search_socket(struct sockaddr_at *to,
                              struct atalk_iface *atif)
{
      struct sock *s;
      struct hlist_node *node;

      read_lock_bh(&atalk_sockets_lock);
      sk_for_each(s, node, &atalk_sockets) {
            struct atalk_sock *at = at_sk(s);

            if (to->sat_port != at->src_port)
                  continue;

            if (to->sat_addr.s_net == ATADDR_ANYNET &&
                to->sat_addr.s_node == ATADDR_BCAST)
                  goto found;

            if (to->sat_addr.s_net == at->src_net &&
                (to->sat_addr.s_node == at->src_node ||
                 to->sat_addr.s_node == ATADDR_BCAST ||
                 to->sat_addr.s_node == ATADDR_ANYNODE))
                  goto found;

            /* XXXX.0 -- we got a request for this router. make sure
             * that the node is appropriately set. */
            if (to->sat_addr.s_node == ATADDR_ANYNODE &&
                to->sat_addr.s_net != ATADDR_ANYNET &&
                atif->address.s_node == at->src_node) {
                  to->sat_addr.s_node = atif->address.s_node;
                  goto found;
            }
      }
      s = NULL;
found:
      read_unlock_bh(&atalk_sockets_lock);
      return s;
}

/**
 * atalk_find_or_insert_socket - Try to find a socket matching ADDR
 * @sk - socket to insert in the list if it is not there already
 * @sat - address to search for
 *
 * Try to find a socket matching ADDR in the socket list, if found then return
 * it. If not, insert SK into the socket list.
 *
 * This entire operation must execute atomically.
 */
static struct sock *atalk_find_or_insert_socket(struct sock *sk,
                                    struct sockaddr_at *sat)
{
      struct sock *s;
      struct hlist_node *node;
      struct atalk_sock *at;

      write_lock_bh(&atalk_sockets_lock);
      sk_for_each(s, node, &atalk_sockets) {
            at = at_sk(s);

            if (at->src_net == sat->sat_addr.s_net &&
                at->src_node == sat->sat_addr.s_node &&
                at->src_port == sat->sat_port)
                  goto found;
      }
      s = NULL;
      __atalk_insert_socket(sk); /* Wheee, it's free, assign and insert. */
found:
      write_unlock_bh(&atalk_sockets_lock);
      return s;
}

static void atalk_destroy_timer(unsigned long data)
{
      struct sock *sk = (struct sock *)data;

      if (atomic_read(&sk->sk_wmem_alloc) ||
          atomic_read(&sk->sk_rmem_alloc)) {
            sk->sk_timer.expires = jiffies + SOCK_DESTROY_TIME;
            add_timer(&sk->sk_timer);
      } else
            sock_put(sk);
}

static inline void atalk_destroy_socket(struct sock *sk)
{
      atalk_remove_socket(sk);
      skb_queue_purge(&sk->sk_receive_queue);

      if (atomic_read(&sk->sk_wmem_alloc) ||
          atomic_read(&sk->sk_rmem_alloc)) {
            init_timer(&sk->sk_timer);
            sk->sk_timer.expires    = jiffies + SOCK_DESTROY_TIME;
            sk->sk_timer.function   = atalk_destroy_timer;
            sk->sk_timer.data = (unsigned long)sk;
            add_timer(&sk->sk_timer);
      } else
            sock_put(sk);
}

/**************************************************************************\
*                                                                          *
* Routing tables for the AppleTalk socket layer.                           *
*                                                                          *
\**************************************************************************/

/* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
struct atalk_route *atalk_routes;
DEFINE_RWLOCK(atalk_routes_lock);

struct atalk_iface *atalk_interfaces;
DEFINE_RWLOCK(atalk_interfaces_lock);

/* For probing devices or in a routerless network */
struct atalk_route atrtr_default;

/* AppleTalk interface control */
/*
 * Drop a device. Doesn't drop any of its routes - that is the caller's
 * problem. Called when we down the interface or delete the address.
 */
static void atif_drop_device(struct net_device *dev)
{
      struct atalk_iface **iface = &atalk_interfaces;
      struct atalk_iface *tmp;

      write_lock_bh(&atalk_interfaces_lock);
      while ((tmp = *iface) != NULL) {
            if (tmp->dev == dev) {
                  *iface = tmp->next;
                  dev_put(dev);
                  kfree(tmp);
                  dev->atalk_ptr = NULL;
            } else
                  iface = &tmp->next;
      }
      write_unlock_bh(&atalk_interfaces_lock);
}

static struct atalk_iface *atif_add_device(struct net_device *dev,
                                 struct atalk_addr *sa)
{
      struct atalk_iface *iface = kzalloc(sizeof(*iface), GFP_KERNEL);

      if (!iface)
            goto out;

      dev_hold(dev);
      iface->dev = dev;
      dev->atalk_ptr = iface;
      iface->address = *sa;
      iface->status = 0;

      write_lock_bh(&atalk_interfaces_lock);
      iface->next = atalk_interfaces;
      atalk_interfaces = iface;
      write_unlock_bh(&atalk_interfaces_lock);
out:
      return iface;
}

/* Perform phase 2 AARP probing on our tentative address */
static int atif_probe_device(struct atalk_iface *atif)
{
      int netrange = ntohs(atif->nets.nr_lastnet) -
                  ntohs(atif->nets.nr_firstnet) + 1;
      int probe_net = ntohs(atif->address.s_net);
      int probe_node = atif->address.s_node;
      int netct, nodect;

      /* Offset the network we start probing with */
      if (probe_net == ATADDR_ANYNET) {
            probe_net = ntohs(atif->nets.nr_firstnet);
            if (netrange)
                  probe_net += jiffies % netrange;
      }
      if (probe_node == ATADDR_ANYNODE)
            probe_node = jiffies & 0xFF;

      /* Scan the networks */
      atif->status |= ATIF_PROBE;
      for (netct = 0; netct <= netrange; netct++) {
            /* Sweep the available nodes from a given start */
            atif->address.s_net = htons(probe_net);
            for (nodect = 0; nodect < 256; nodect++) {
                  atif->address.s_node = (nodect + probe_node) & 0xFF;
                  if (atif->address.s_node > 0 &&
                      atif->address.s_node < 254) {
                        /* Probe a proposed address */
                        aarp_probe_network(atif);

                        if (!(atif->status & ATIF_PROBE_FAIL)) {
                              atif->status &= ~ATIF_PROBE;
                              return 0;
                        }
                  }
                  atif->status &= ~ATIF_PROBE_FAIL;
            }
            probe_net++;
            if (probe_net > ntohs(atif->nets.nr_lastnet))
                  probe_net = ntohs(atif->nets.nr_firstnet);
      }
      atif->status &= ~ATIF_PROBE;

      return -EADDRINUSE;     /* Network is full... */
}


/* Perform AARP probing for a proxy address */
static int atif_proxy_probe_device(struct atalk_iface *atif,
                           struct atalk_addr* proxy_addr)
{
      int netrange = ntohs(atif->nets.nr_lastnet) -
                  ntohs(atif->nets.nr_firstnet) + 1;
      /* we probe the interface's network */
      int probe_net = ntohs(atif->address.s_net);
      int probe_node = ATADDR_ANYNODE;        /* we'll take anything */
      int netct, nodect;

      /* Offset the network we start probing with */
      if (probe_net == ATADDR_ANYNET) {
            probe_net = ntohs(atif->nets.nr_firstnet);
            if (netrange)
                  probe_net += jiffies % netrange;
      }

      if (probe_node == ATADDR_ANYNODE)
            probe_node = jiffies & 0xFF;

      /* Scan the networks */
      for (netct = 0; netct <= netrange; netct++) {
            /* Sweep the available nodes from a given start */
            proxy_addr->s_net = htons(probe_net);
            for (nodect = 0; nodect < 256; nodect++) {
                  proxy_addr->s_node = (nodect + probe_node) & 0xFF;
                  if (proxy_addr->s_node > 0 &&
                      proxy_addr->s_node < 254) {
                        /* Tell AARP to probe a proposed address */
                        int ret = aarp_proxy_probe_network(atif,
                                                    proxy_addr);

                        if (ret != -EADDRINUSE)
                              return ret;
                  }
            }
            probe_net++;
            if (probe_net > ntohs(atif->nets.nr_lastnet))
                  probe_net = ntohs(atif->nets.nr_firstnet);
      }

      return -EADDRINUSE;     /* Network is full... */
}


struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
{
      struct atalk_iface *iface = dev->atalk_ptr;
      return iface ? &iface->address : NULL;
}

static struct atalk_addr *atalk_find_primary(void)
{
      struct atalk_iface *fiface = NULL;
      struct atalk_addr *retval;
      struct atalk_iface *iface;

      /*
       * Return a point-to-point interface only if
       * there is no non-ptp interface available.
       */
      read_lock_bh(&atalk_interfaces_lock);
      for (iface = atalk_interfaces; iface; iface = iface->next) {
            if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
                  fiface = iface;
            if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
                  retval = &iface->address;
                  goto out;
            }
      }

      if (fiface)
            retval = &fiface->address;
      else if (atalk_interfaces)
            retval = &atalk_interfaces->address;
      else
            retval = NULL;
out:
      read_unlock_bh(&atalk_interfaces_lock);
      return retval;
}

/*
 * Find a match for 'any network' - ie any of our interfaces with that
 * node number will do just nicely.
 */
static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
{
      struct atalk_iface *iface = dev->atalk_ptr;

      if (!iface || iface->status & ATIF_PROBE)
            goto out_err;

      if (node != ATADDR_BCAST &&
          iface->address.s_node != node &&
          node != ATADDR_ANYNODE)
            goto out_err;
out:
      return iface;
out_err:
      iface = NULL;
      goto out;
}

/* Find a match for a specific network:node pair */
static struct atalk_iface *atalk_find_interface(__be16 net, int node)
{
      struct atalk_iface *iface;

      read_lock_bh(&atalk_interfaces_lock);
      for (iface = atalk_interfaces; iface; iface = iface->next) {
            if ((node == ATADDR_BCAST ||
                 node == ATADDR_ANYNODE ||
                 iface->address.s_node == node) &&
                iface->address.s_net == net &&
                !(iface->status & ATIF_PROBE))
                  break;

            /* XXXX.0 -- net.0 returns the iface associated with net */
            if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
                ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
                ntohs(net) <= ntohs(iface->nets.nr_lastnet))
                  break;
      }
      read_unlock_bh(&atalk_interfaces_lock);
      return iface;
}


/*
 * Find a route for an AppleTalk packet. This ought to get cached in
 * the socket (later on...). We know about host routes and the fact
 * that a route must be direct to broadcast.
 */
static struct atalk_route *atrtr_find(struct atalk_addr *target)
{
      /*
       * we must search through all routes unless we find a
       * host route, because some host routes might overlap
       * network routes
       */
      struct atalk_route *net_route = NULL;
      struct atalk_route *r;

      read_lock_bh(&atalk_routes_lock);
      for (r = atalk_routes; r; r = r->next) {
            if (!(r->flags & RTF_UP))
                  continue;

            if (r->target.s_net == target->s_net) {
                  if (r->flags & RTF_HOST) {
                        /*
                         * if this host route is for the target,
                         * the we're done
                         */
                        if (r->target.s_node == target->s_node)
                              goto out;
                  } else
                        /*
                         * this route will work if there isn't a
                         * direct host route, so cache it
                         */
                        net_route = r;
            }
      }

      /*
       * if we found a network route but not a direct host
       * route, then return it
       */
      if (net_route)
            r = net_route;
      else if (atrtr_default.dev)
            r = &atrtr_default;
      else /* No route can be found */
            r = NULL;
out:
      read_unlock_bh(&atalk_routes_lock);
      return r;
}


/*
 * Given an AppleTalk network, find the device to use. This can be
 * a simple lookup.
 */
struct net_device *atrtr_get_dev(struct atalk_addr *sa)
{
      struct atalk_route *atr = atrtr_find(sa);
      return atr ? atr->dev : NULL;
}

/* Set up a default router */
static void atrtr_set_default(struct net_device *dev)
{
      atrtr_default.dev      = dev;
      atrtr_default.flags          = RTF_UP;
      atrtr_default.gateway.s_net  = htons(0);
      atrtr_default.gateway.s_node = 0;
}

/*
 * Add a router. Basically make sure it looks valid and stuff the
 * entry in the list. While it uses netranges we always set them to one
 * entry to work like netatalk.
 */
static int atrtr_create(struct rtentry *r, struct net_device *devhint)
{
      struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
      struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
      struct atalk_route *rt;
      struct atalk_iface *iface, *riface;
      int retval = -EINVAL;

      /*
       * Fixme: Raise/Lower a routing change semaphore for these
       * operations.
       */

      /* Validate the request */
      if (ta->sat_family != AF_APPLETALK ||
          (!devhint && ga->sat_family != AF_APPLETALK))
            goto out;

      /* Now walk the routing table and make our decisions */
      write_lock_bh(&atalk_routes_lock);
      for (rt = atalk_routes; rt; rt = rt->next) {
            if (r->rt_flags != rt->flags)
                  continue;

            if (ta->sat_addr.s_net == rt->target.s_net) {
                  if (!(rt->flags & RTF_HOST))
                        break;
                  if (ta->sat_addr.s_node == rt->target.s_node)
                        break;
            }
      }

      if (!devhint) {
            riface = NULL;

            read_lock_bh(&atalk_interfaces_lock);
            for (iface = atalk_interfaces; iface; iface = iface->next) {
                  if (!riface &&
                      ntohs(ga->sat_addr.s_net) >=
                              ntohs(iface->nets.nr_firstnet) &&
                      ntohs(ga->sat_addr.s_net) <=
                              ntohs(iface->nets.nr_lastnet))
                        riface = iface;

                  if (ga->sat_addr.s_net == iface->address.s_net &&
                      ga->sat_addr.s_node == iface->address.s_node)
                        riface = iface;
            }
            read_unlock_bh(&atalk_interfaces_lock);

            retval = -ENETUNREACH;
            if (!riface)
                  goto out_unlock;

            devhint = riface->dev;
      }

      if (!rt) {
            rt = kzalloc(sizeof(*rt), GFP_ATOMIC);

            retval = -ENOBUFS;
            if (!rt)
                  goto out_unlock;

            rt->next = atalk_routes;
            atalk_routes = rt;
      }

      /* Fill in the routing entry */
      rt->target  = ta->sat_addr;
      dev_hold(devhint);
      rt->dev     = devhint;
      rt->flags   = r->rt_flags;
      rt->gateway = ga->sat_addr;

      retval = 0;
out_unlock:
      write_unlock_bh(&atalk_routes_lock);
out:
      return retval;
}

/* Delete a route. Find it and discard it */
static int atrtr_delete(struct atalk_addr * addr)
{
      struct atalk_route **r = &atalk_routes;
      int retval = 0;
      struct atalk_route *tmp;

      write_lock_bh(&atalk_routes_lock);
      while ((tmp = *r) != NULL) {
            if (tmp->target.s_net == addr->s_net &&
                (!(tmp->flags&RTF_GATEWAY) ||
                 tmp->target.s_node == addr->s_node)) {
                  *r = tmp->next;
                  dev_put(tmp->dev);
                  kfree(tmp);
                  goto out;
            }
            r = &tmp->next;
      }
      retval = -ENOENT;
out:
      write_unlock_bh(&atalk_routes_lock);
      return retval;
}

/*
 * Called when a device is downed. Just throw away any routes
 * via it.
 */
static void atrtr_device_down(struct net_device *dev)
{
      struct atalk_route **r = &atalk_routes;
      struct atalk_route *tmp;

      write_lock_bh(&atalk_routes_lock);
      while ((tmp = *r) != NULL) {
            if (tmp->dev == dev) {
                  *r = tmp->next;
                  dev_put(dev);
                  kfree(tmp);
            } else
                  r = &tmp->next;
      }
      write_unlock_bh(&atalk_routes_lock);

      if (atrtr_default.dev == dev)
            atrtr_set_default(NULL);
}

/* Actually down the interface */
static inline void atalk_dev_down(struct net_device *dev)
{
      atrtr_device_down(dev); /* Remove all routes for the device */
      aarp_device_down(dev);  /* Remove AARP entries for the device */
      atif_drop_device(dev);  /* Remove the device */
}

/*
 * A device event has occurred. Watch for devices going down and
 * delete our use of them (iface and route).
 */
static int ddp_device_event(struct notifier_block *this, unsigned long event,
                      void *ptr)
{
      struct net_device *dev = ptr;

      if (dev->nd_net != &init_net)
            return NOTIFY_DONE;

      if (event == NETDEV_DOWN)
            /* Discard any use of this */
            atalk_dev_down(dev);

      return NOTIFY_DONE;
}

/* ioctl calls. Shouldn't even need touching */
/* Device configuration ioctl calls */
static int atif_ioctl(int cmd, void __user *arg)
{
      static char aarp_mcast[6] = { 0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF };
      struct ifreq atreq;
      struct atalk_netrange *nr;
      struct sockaddr_at *sa;
      struct net_device *dev;
      struct atalk_iface *atif;
      int ct;
      int limit;
      struct rtentry rtdef;
      int add_route;

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

      dev = __dev_get_by_name(&init_net, atreq.ifr_name);
      if (!dev)
            return -ENODEV;

      sa = (struct sockaddr_at *)&atreq.ifr_addr;
      atif = atalk_find_dev(dev);

      switch (cmd) {
            case SIOCSIFADDR:
                  if (!capable(CAP_NET_ADMIN))
                        return -EPERM;
                  if (sa->sat_family != AF_APPLETALK)
                        return -EINVAL;
                  if (dev->type != ARPHRD_ETHER &&
                      dev->type != ARPHRD_LOOPBACK &&
                      dev->type != ARPHRD_LOCALTLK &&
                      dev->type != ARPHRD_PPP)
                        return -EPROTONOSUPPORT;

                  nr = (struct atalk_netrange *)&sa->sat_zero[0];
                  add_route = 1;

                  /*
                   * if this is a point-to-point iface, and we already
                   * have an iface for this AppleTalk address, then we
                   * should not add a route
                   */
                  if ((dev->flags & IFF_POINTOPOINT) &&
                      atalk_find_interface(sa->sat_addr.s_net,
                                     sa->sat_addr.s_node)) {
                        printk(KERN_DEBUG "AppleTalk: point-to-point "
                                      "interface added with "
                                      "existing address\n");
                        add_route = 0;
                  }

                  /*
                   * Phase 1 is fine on LocalTalk but we don't do
                   * EtherTalk phase 1. Anyone wanting to add it go ahead.
                   */
                  if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
                        return -EPROTONOSUPPORT;
                  if (sa->sat_addr.s_node == ATADDR_BCAST ||
                      sa->sat_addr.s_node == 254)
                        return -EINVAL;
                  if (atif) {
                        /* Already setting address */
                        if (atif->status & ATIF_PROBE)
                              return -EBUSY;

                        atif->address.s_net  = sa->sat_addr.s_net;
                        atif->address.s_node = sa->sat_addr.s_node;
                        atrtr_device_down(dev); /* Flush old routes */
                  } else {
                        atif = atif_add_device(dev, &sa->sat_addr);
                        if (!atif)
                              return -ENOMEM;
                  }
                  atif->nets = *nr;

                  /*
                   * Check if the chosen address is used. If so we
                   * error and atalkd will try another.
                   */

                  if (!(dev->flags & IFF_LOOPBACK) &&
                      !(dev->flags & IFF_POINTOPOINT) &&
                      atif_probe_device(atif) < 0) {
                        atif_drop_device(dev);
                        return -EADDRINUSE;
                  }

                  /* Hey it worked - add the direct routes */
                  sa = (struct sockaddr_at *)&rtdef.rt_gateway;
                  sa->sat_family = AF_APPLETALK;
                  sa->sat_addr.s_net  = atif->address.s_net;
                  sa->sat_addr.s_node = atif->address.s_node;
                  sa = (struct sockaddr_at *)&rtdef.rt_dst;
                  rtdef.rt_flags = RTF_UP;
                  sa->sat_family = AF_APPLETALK;
                  sa->sat_addr.s_node = ATADDR_ANYNODE;
                  if (dev->flags & IFF_LOOPBACK ||
                      dev->flags & IFF_POINTOPOINT)
                        rtdef.rt_flags |= RTF_HOST;

                  /* Routerless initial state */
                  if (nr->nr_firstnet == htons(0) &&
                      nr->nr_lastnet == htons(0xFFFE)) {
                        sa->sat_addr.s_net = atif->address.s_net;
                        atrtr_create(&rtdef, dev);
                        atrtr_set_default(dev);
                  } else {
                        limit = ntohs(nr->nr_lastnet);
                        if (limit - ntohs(nr->nr_firstnet) > 4096) {
                              printk(KERN_WARNING "Too many routes/"
                                              "iface.\n");
                              return -EINVAL;
                        }
                        if (add_route)
                              for (ct = ntohs(nr->nr_firstnet);
                                   ct <= limit; ct++) {
                                    sa->sat_addr.s_net = htons(ct);
                                    atrtr_create(&rtdef, dev);
                              }
                  }
                  dev_mc_add(dev, aarp_mcast, 6, 1);
                  return 0;

            case SIOCGIFADDR:
                  if (!atif)
                        return -EADDRNOTAVAIL;

                  sa->sat_family = AF_APPLETALK;
                  sa->sat_addr = atif->address;
                  break;

            case SIOCGIFBRDADDR:
                  if (!atif)
                        return -EADDRNOTAVAIL;

                  sa->sat_family = AF_APPLETALK;
                  sa->sat_addr.s_net = atif->address.s_net;
                  sa->sat_addr.s_node = ATADDR_BCAST;
                  break;

            case SIOCATALKDIFADDR:
            case SIOCDIFADDR:
                  if (!capable(CAP_NET_ADMIN))
                        return -EPERM;
                  if (sa->sat_family != AF_APPLETALK)
                        return -EINVAL;
                  atalk_dev_down(dev);
                  break;

            case SIOCSARP:
                  if (!capable(CAP_NET_ADMIN))
                        return -EPERM;
                  if (sa->sat_family != AF_APPLETALK)
                        return -EINVAL;
                  if (!atif)
                        return -EADDRNOTAVAIL;

                  /*
                   * for now, we only support proxy AARP on ELAP;
                   * we should be able to do it for LocalTalk, too.
                   */
                  if (dev->type != ARPHRD_ETHER)
                        return -EPROTONOSUPPORT;

                  /*
                   * atif points to the current interface on this network;
                   * we aren't concerned about its current status (at
                   * least for now), but it has all the settings about
                   * the network we're going to probe. Consequently, it
                   * must exist.
                   */
                  if (!atif)
                        return -EADDRNOTAVAIL;

                  nr = (struct atalk_netrange *)&(atif->nets);
                  /*
                   * Phase 1 is fine on Localtalk but we don't do
                   * Ethertalk phase 1. Anyone wanting to add it go ahead.
                   */
                  if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
                        return -EPROTONOSUPPORT;

                  if (sa->sat_addr.s_node == ATADDR_BCAST ||
                      sa->sat_addr.s_node == 254)
                        return -EINVAL;

                  /*
                   * Check if the chosen address is used. If so we
                   * error and ATCP will try another.
                   */
                  if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
                        return -EADDRINUSE;

                  /*
                   * We now have an address on the local network, and
                   * the AARP code will defend it for us until we take it
                   * down. We don't set up any routes right now, because
                   * ATCP will install them manually via SIOCADDRT.
                   */
                  break;

            case SIOCDARP:
                  if (!capable(CAP_NET_ADMIN))
                        return -EPERM;
                  if (sa->sat_family != AF_APPLETALK)
                        return -EINVAL;
                  if (!atif)
                        return -EADDRNOTAVAIL;

                  /* give to aarp module to remove proxy entry */
                  aarp_proxy_remove(atif->dev, &(sa->sat_addr));
                  return 0;
      }

      return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
}

/* Routing ioctl() calls */
static int atrtr_ioctl(unsigned int cmd, void __user *arg)
{
      struct rtentry rt;

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

      switch (cmd) {
            case SIOCDELRT:
                  if (rt.rt_dst.sa_family != AF_APPLETALK)
                        return -EINVAL;
                  return atrtr_delete(&((struct sockaddr_at *)
                                    &rt.rt_dst)->sat_addr);

            case SIOCADDRT: {
                  struct net_device *dev = NULL;
                  if (rt.rt_dev) {
                        char name[IFNAMSIZ];
                        if (copy_from_user(name, rt.rt_dev, IFNAMSIZ-1))
                              return -EFAULT;
                        name[IFNAMSIZ-1] = '\0';
                        dev = __dev_get_by_name(&init_net, name);
                        if (!dev)
                              return -ENODEV;
                  }
                  return atrtr_create(&rt, dev);
            }
      }
      return -EINVAL;
}

/**************************************************************************\
*                                                                          *
* Handling for system calls applied via the various interfaces to an       *
* AppleTalk socket object.                                                 *
*                                                                          *
\**************************************************************************/

/*
 * Checksum: This is 'optional'. It's quite likely also a good
 * candidate for assembler hackery 8)
 */
static unsigned long atalk_sum_partial(const unsigned char *data,
                               int len, unsigned long sum)
{
      /* This ought to be unwrapped neatly. I'll trust gcc for now */
      while (len--) {
            sum += *data;
            sum <<= 1;
            if (sum & 0x10000) {
                  sum++;
                  sum &= 0xffff;
            }
            data++;
      }
      return sum;
}

/*  Checksum skb data --  similar to skb_checksum  */
static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
                           int len, unsigned long sum)
{
      int start = skb_headlen(skb);
      int i, copy;

      /* checksum stuff in header space */
      if ( (copy = start - offset) > 0) {
            if (copy > len)
                  copy = len;
            sum = atalk_sum_partial(skb->data + offset, copy, sum);
            if ( (len -= copy) == 0)
                  return sum;

            offset += copy;
      }

      /* checksum stuff in frags */
      for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
            int end;

            BUG_TRAP(start <= offset + len);

            end = start + skb_shinfo(skb)->frags[i].size;
            if ((copy = end - offset) > 0) {
                  u8 *vaddr;
                  skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

                  if (copy > len)
                        copy = len;
                  vaddr = kmap_skb_frag(frag);
                  sum = atalk_sum_partial(vaddr + frag->page_offset +
                                      offset - start, copy, sum);
                  kunmap_skb_frag(vaddr);

                  if (!(len -= copy))
                        return sum;
                  offset += copy;
            }
            start = end;
      }

      if (skb_shinfo(skb)->frag_list) {
            struct sk_buff *list = skb_shinfo(skb)->frag_list;

            for (; list; list = list->next) {
                  int end;

                  BUG_TRAP(start <= offset + len);

                  end = start + list->len;
                  if ((copy = end - offset) > 0) {
                        if (copy > len)
                              copy = len;
                        sum = atalk_sum_skb(list, offset - start,
                                        copy, sum);
                        if ((len -= copy) == 0)
                              return sum;
                        offset += copy;
                  }
                  start = end;
            }
      }

      BUG_ON(len > 0);

      return sum;
}

static __be16 atalk_checksum(const struct sk_buff *skb, int len)
{
      unsigned long sum;

      /* skip header 4 bytes */
      sum = atalk_sum_skb(skb, 4, len-4, 0);

      /* Use 0xFFFF for 0. 0 itself means none */
      return sum ? htons((unsigned short)sum) : htons(0xFFFF);
}

static struct proto ddp_proto = {
      .name   = "DDP",
      .owner        = THIS_MODULE,
      .obj_size = sizeof(struct atalk_sock),
};

/*
 * Create a socket. Initialise the socket, blank the addresses
 * set the state.
 */
static int atalk_create(struct net *net, struct socket *sock, int protocol)
{
      struct sock *sk;
      int rc = -ESOCKTNOSUPPORT;

      if (net != &init_net)
            return -EAFNOSUPPORT;

      /*
       * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
       * and gives you the full ELAP frame. Should be handy for CAP 8)
       */
      if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
            goto out;
      rc = -ENOMEM;
      sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto);
      if (!sk)
            goto out;
      rc = 0;
      sock->ops = &atalk_dgram_ops;
      sock_init_data(sock, sk);

      /* Checksums on by default */
      sock_set_flag(sk, SOCK_ZAPPED);
out:
      return rc;
}

/* Free a socket. No work needed */
static int atalk_release(struct socket *sock)
{
      struct sock *sk = sock->sk;

      if (sk) {
            sock_orphan(sk);
            sock->sk = NULL;
            atalk_destroy_socket(sk);
      }
      return 0;
}

/**
 * atalk_pick_and_bind_port - Pick a source port when one is not given
 * @sk - socket to insert into the tables
 * @sat - address to search for
 *
 * Pick a source port when one is not given. If we can find a suitable free
 * one, we insert the socket into the tables using it.
 *
 * This whole operation must be atomic.
 */
static int atalk_pick_and_bind_port(struct sock *sk, struct sockaddr_at *sat)
{
      int retval;

      write_lock_bh(&atalk_sockets_lock);

      for (sat->sat_port = ATPORT_RESERVED;
           sat->sat_port < ATPORT_LAST;
           sat->sat_port++) {
            struct sock *s;
            struct hlist_node *node;

            sk_for_each(s, node, &atalk_sockets) {
                  struct atalk_sock *at = at_sk(s);

                  if (at->src_net == sat->sat_addr.s_net &&
                      at->src_node == sat->sat_addr.s_node &&
                      at->src_port == sat->sat_port)
                        goto try_next_port;
            }

            /* Wheee, it's free, assign and insert. */
            __atalk_insert_socket(sk);
            at_sk(sk)->src_port = sat->sat_port;
            retval = 0;
            goto out;

try_next_port:;
      }

      retval = -EBUSY;
out:
      write_unlock_bh(&atalk_sockets_lock);
      return retval;
}

static int atalk_autobind(struct sock *sk)
{
      struct atalk_sock *at = at_sk(sk);
      struct sockaddr_at sat;
      struct atalk_addr *ap = atalk_find_primary();
      int n = -EADDRNOTAVAIL;

      if (!ap || ap->s_net == htons(ATADDR_ANYNET))
            goto out;

      at->src_net  = sat.sat_addr.s_net  = ap->s_net;
      at->src_node = sat.sat_addr.s_node = ap->s_node;

      n = atalk_pick_and_bind_port(sk, &sat);
      if (!n)
            sock_reset_flag(sk, SOCK_ZAPPED);
out:
      return n;
}

/* Set the address 'our end' of the connection */
static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
      struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
      struct sock *sk = sock->sk;
      struct atalk_sock *at = at_sk(sk);

      if (!sock_flag(sk, SOCK_ZAPPED) ||
          addr_len != sizeof(struct sockaddr_at))
            return -EINVAL;

      if (addr->sat_family != AF_APPLETALK)
            return -EAFNOSUPPORT;

      if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
            struct atalk_addr *ap = atalk_find_primary();

            if (!ap)
                  return -EADDRNOTAVAIL;

            at->src_net  = addr->sat_addr.s_net = ap->s_net;
            at->src_node = addr->sat_addr.s_node= ap->s_node;
      } else {
            if (!atalk_find_interface(addr->sat_addr.s_net,
                                addr->sat_addr.s_node))
                  return -EADDRNOTAVAIL;

            at->src_net  = addr->sat_addr.s_net;
            at->src_node = addr->sat_addr.s_node;
      }

      if (addr->sat_port == ATADDR_ANYPORT) {
            int n = atalk_pick_and_bind_port(sk, addr);

            if (n < 0)
                  return n;
      } else {
            at->src_port = addr->sat_port;

            if (atalk_find_or_insert_socket(sk, addr))
                  return -EADDRINUSE;
      }

      sock_reset_flag(sk, SOCK_ZAPPED);
      return 0;
}

/* Set the address we talk to */
static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
                   int addr_len, int flags)
{
      struct sock *sk = sock->sk;
      struct atalk_sock *at = at_sk(sk);
      struct sockaddr_at *addr;

      sk->sk_state   = TCP_CLOSE;
      sock->state = SS_UNCONNECTED;

      if (addr_len != sizeof(*addr))
            return -EINVAL;

      addr = (struct sockaddr_at *)uaddr;

      if (addr->sat_family != AF_APPLETALK)
            return -EAFNOSUPPORT;

      if (addr->sat_addr.s_node == ATADDR_BCAST &&
          !sock_flag(sk, SOCK_BROADCAST)) {
#if 1
            printk(KERN_WARNING "%s is broken and did not set "
                            "SO_BROADCAST. It will break when 2.2 is "
                            "released.\n",
                  current->comm);
#else
            return -EACCES;
#endif
      }

      if (sock_flag(sk, SOCK_ZAPPED))
            if (atalk_autobind(sk) < 0)
                  return -EBUSY;

      if (!atrtr_get_dev(&addr->sat_addr))
            return -ENETUNREACH;

      at->dest_port = addr->sat_port;
      at->dest_net  = addr->sat_addr.s_net;
      at->dest_node = addr->sat_addr.s_node;

      sock->state  = SS_CONNECTED;
      sk->sk_state = TCP_ESTABLISHED;
      return 0;
}

/*
 * Find the name of an AppleTalk socket. Just copy the right
 * fields into the sockaddr.
 */
static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
                   int *uaddr_len, int peer)
{
      struct sockaddr_at sat;
      struct sock *sk = sock->sk;
      struct atalk_sock *at = at_sk(sk);

      if (sock_flag(sk, SOCK_ZAPPED))
            if (atalk_autobind(sk) < 0)
                  return -ENOBUFS;

      *uaddr_len = sizeof(struct sockaddr_at);

      if (peer) {
            if (sk->sk_state != TCP_ESTABLISHED)
                  return -ENOTCONN;

            sat.sat_addr.s_net  = at->dest_net;
            sat.sat_addr.s_node = at->dest_node;
            sat.sat_port          = at->dest_port;
      } else {
            sat.sat_addr.s_net  = at->src_net;
            sat.sat_addr.s_node = at->src_node;
            sat.sat_port          = at->src_port;
      }

      sat.sat_family = AF_APPLETALK;
      memcpy(uaddr, &sat, sizeof(sat));
      return 0;
}

#if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
{
      return skb->data[12] == 22;
}

static int handle_ip_over_ddp(struct sk_buff *skb)
{
      struct net_device *dev = __dev_get_by_name(&init_net, "ipddp0");
      struct net_device_stats *stats;

      /* This needs to be able to handle ipddp"N" devices */
      if (!dev)
            return -ENODEV;

      skb->protocol = htons(ETH_P_IP);
      skb_pull(skb, 13);
      skb->dev   = dev;
      skb_reset_transport_header(skb);

      stats = dev->priv;
      stats->rx_packets++;
      stats->rx_bytes += skb->len + 13;
      netif_rx(skb);  /* Send the SKB up to a higher place. */
      return 0;
}
#else
/* make it easy for gcc to optimize this test out, i.e. kill the code */
#define is_ip_over_ddp(skb) 0
#define handle_ip_over_ddp(skb) 0
#endif

static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
                         struct ddpehdr *ddp, __u16 len_hops,
                         int origlen)
{
      struct atalk_route *rt;
      struct atalk_addr ta;

      /*
       * Don't route multicast, etc., packets, or packets sent to "this
       * network"
       */
      if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
            /*
             * FIXME:
             *
             * Can it ever happen that a packet is from a PPP iface and
             * needs to be broadcast onto the default network?
             */
            if (dev->type == ARPHRD_PPP)
                  printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
                                "packet received from PPP iface\n");
            goto free_it;
      }

      ta.s_net  = ddp->deh_dnet;
      ta.s_node = ddp->deh_dnode;

      /* Route the packet */
      rt = atrtr_find(&ta);
      /* increment hops count */
      len_hops += 1 << 10;
      if (!rt || !(len_hops & (15 << 10)))
            goto free_it;

      /* FIXME: use skb->cb to be able to use shared skbs */

      /*
       * Route goes through another gateway, so set the target to the
       * gateway instead.
       */

      if (rt->flags & RTF_GATEWAY) {
            ta.s_net  = rt->gateway.s_net;
            ta.s_node = rt->gateway.s_node;
      }

      /* Fix up skb->len field */
      skb_trim(skb, min_t(unsigned int, origlen,
                      (rt->dev->hard_header_len +
                       ddp_dl->header_length + (len_hops & 1023))));

      /* FIXME: use skb->cb to be able to use shared skbs */
      ddp->deh_len_hops = htons(len_hops);

      /*
       * Send the buffer onwards
       *
       * Now we must always be careful. If it's come from LocalTalk to
       * EtherTalk it might not fit
       *
       * Order matters here: If a packet has to be copied to make a new
       * headroom (rare hopefully) then it won't need unsharing.
       *
       * Note. ddp-> becomes invalid at the realloc.
       */
      if (skb_headroom(skb) < 22) {
            /* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
            struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
            kfree_skb(skb);
            if (!nskb)
                  goto out;
            skb = nskb;
      } else
            skb = skb_unshare(skb, GFP_ATOMIC);

      /*
       * If the buffer didn't vanish into the lack of space bitbucket we can
       * send it.
       */
      if (skb && aarp_send_ddp(rt->dev, skb, &ta, NULL) == -1)
            goto free_it;
out:
      return;
free_it:
      kfree_skb(skb);
}

/**
 *    atalk_rcv - Receive a packet (in skb) from device dev
 *    @skb - packet received
 *    @dev - network device where the packet comes from
 *    @pt - packet type
 *
 *    Receive a packet (in skb) from device dev. This has come from the SNAP
 *    decoder, and on entry skb->transport_header is the DDP header, skb->len
 *    is the DDP header, skb->len is the DDP length. The physical headers
 *    have been extracted. PPP should probably pass frames marked as for this
 *    layer.  [ie ARPHRD_ETHERTALK]
 */
static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
                 struct packet_type *pt, struct net_device *orig_dev)
{
      struct ddpehdr *ddp;
      struct sock *sock;
      struct atalk_iface *atif;
      struct sockaddr_at tosat;
      int origlen;
      __u16 len_hops;

      if (dev->nd_net != &init_net)
            goto freeit;

      /* Don't mangle buffer if shared */
      if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
            goto out;

      /* Size check and make sure header is contiguous */
      if (!pskb_may_pull(skb, sizeof(*ddp)))
            goto freeit;

      ddp = ddp_hdr(skb);

      len_hops = ntohs(ddp->deh_len_hops);

      /* Trim buffer in case of stray trailing data */
      origlen = skb->len;
      skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));

      /*
       * Size check to see if ddp->deh_len was crap
       * (Otherwise we'll detonate most spectacularly
       * in the middle of atalk_checksum() or recvmsg()).
       */
      if (skb->len < sizeof(*ddp) || skb->len < (len_hops & 1023)) {
            pr_debug("AppleTalk: dropping corrupted frame (deh_len=%u, "
                   "skb->len=%u)\n", len_hops & 1023, skb->len);
            goto freeit;
      }

      /*
       * Any checksums. Note we don't do htons() on this == is assumed to be
       * valid for net byte orders all over the networking code...
       */
      if (ddp->deh_sum &&
          atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
            /* Not a valid AppleTalk frame - dustbin time */
            goto freeit;

      /* Check the packet is aimed at us */
      if (!ddp->deh_dnet)     /* Net 0 is 'this network' */
            atif = atalk_find_anynet(ddp->deh_dnode, dev);
      else
            atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);

      if (!atif) {
            /* Not ours, so we route the packet via the correct
             * AppleTalk iface
             */
            atalk_route_packet(skb, dev, ddp, len_hops, origlen);
            goto out;
      }

      /* if IP over DDP is not selected this code will be optimized out */
      if (is_ip_over_ddp(skb))
            return handle_ip_over_ddp(skb);
      /*
       * Which socket - atalk_search_socket() looks for a *full match*
       * of the <net, node, port> tuple.
       */
      tosat.sat_addr.s_net  = ddp->deh_dnet;
      tosat.sat_addr.s_node = ddp->deh_dnode;
      tosat.sat_port          = ddp->deh_dport;

      sock = atalk_search_socket(&tosat, atif);
      if (!sock) /* But not one of our sockets */
            goto freeit;

      /* Queue packet (standard) */
      skb->sk = sock;

      if (sock_queue_rcv_skb(sock, skb) < 0)
            goto freeit;
out:
      return 0;
freeit:
      kfree_skb(skb);
      goto out;
}

/*
 * Receive a LocalTalk frame. We make some demands on the caller here.
 * Caller must provide enough headroom on the packet to pull the short
 * header and append a long one.
 */
static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
                 struct packet_type *pt, struct net_device *orig_dev)
{
      if (dev->nd_net != &init_net)
            goto freeit;

      /* Expand any short form frames */
      if (skb_mac_header(skb)[2] == 1) {
            struct ddpehdr *ddp;
            /* Find our address */
            struct atalk_addr *ap = atalk_find_dev_addr(dev);

            if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
                  goto freeit;

            /* Don't mangle buffer if shared */
            if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
                  return 0;

            /*
             * The push leaves us with a ddephdr not an shdr, and
             * handily the port bytes in the right place preset.
             */
            ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);

            /* Now fill in the long header */

            /*
             * These two first. The mac overlays the new source/dest
             * network information so we MUST copy these before
             * we write the network numbers !
             */

            ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
            ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */

            ddp->deh_dnet  = ap->s_net;   /* Network number */
            ddp->deh_snet  = ap->s_net;
            ddp->deh_sum   = 0;           /* No checksum */
            /*
             * Not sure about this bit...
             */
            /* Non routable, so force a drop if we slip up later */
            ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
      }
      skb_reset_transport_header(skb);

      return atalk_rcv(skb, dev, pt, orig_dev);
freeit:
      kfree_skb(skb);
      return 0;
}

static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                   size_t len)
{
      struct sock *sk = sock->sk;
      struct atalk_sock *at = at_sk(sk);
      struct sockaddr_at *usat = (struct sockaddr_at *)msg->msg_name;
      int flags = msg->msg_flags;
      int loopback = 0;
      struct sockaddr_at local_satalk, gsat;
      struct sk_buff *skb;
      struct net_device *dev;
      struct ddpehdr *ddp;
      int size;
      struct atalk_route *rt;
      int err;

      if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
            return -EINVAL;

      if (len > DDP_MAXSZ)
            return -EMSGSIZE;

      if (usat) {
            if (sock_flag(sk, SOCK_ZAPPED))
                  if (atalk_autobind(sk) < 0)
                        return -EBUSY;

            if (msg->msg_namelen < sizeof(*usat) ||
                usat->sat_family != AF_APPLETALK)
                  return -EINVAL;

            /* netatalk doesn't implement this check */
            if (usat->sat_addr.s_node == ATADDR_BCAST &&
                !sock_flag(sk, SOCK_BROADCAST)) {
                  printk(KERN_INFO "SO_BROADCAST: Fix your netatalk as "
                               "it will break before 2.2\n");
#if 0
                  return -EPERM;
#endif
            }
      } else {
            if (sk->sk_state != TCP_ESTABLISHED)
                  return -ENOTCONN;
            usat = &local_satalk;
            usat->sat_family      = AF_APPLETALK;
            usat->sat_port          = at->dest_port;
            usat->sat_addr.s_node = at->dest_node;
            usat->sat_addr.s_net  = at->dest_net;
      }

      /* Build a packet */
      SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);

      /* For headers */
      size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;

      if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
            rt = atrtr_find(&usat->sat_addr);
      } else {
            struct atalk_addr at_hint;

            at_hint.s_node = 0;
            at_hint.s_net  = at->src_net;

            rt = atrtr_find(&at_hint);
      }
      if (!rt)
            return -ENETUNREACH;

      dev = rt->dev;

      SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
                  sk, size, dev->name);

      size += dev->hard_header_len;
      skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
      if (!skb)
            return err;

      skb->sk = sk;
      skb_reserve(skb, ddp_dl->header_length);
      skb_reserve(skb, dev->hard_header_len);
      skb->dev = dev;

      SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);

      ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
      ddp->deh_len_hops  = htons(len + sizeof(*ddp));
      ddp->deh_dnet  = usat->sat_addr.s_net;
      ddp->deh_snet  = at->src_net;
      ddp->deh_dnode = usat->sat_addr.s_node;
      ddp->deh_snode = at->src_node;
      ddp->deh_dport = usat->sat_port;
      ddp->deh_sport = at->src_port;

      SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);

      err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
      if (err) {
            kfree_skb(skb);
            return -EFAULT;
      }

      if (sk->sk_no_check == 1)
            ddp->deh_sum = 0;
      else
            ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));

      /*
       * Loopback broadcast packets to non gateway targets (ie routes
       * to group we are in)
       */
      if (ddp->deh_dnode == ATADDR_BCAST &&
          !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
            struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);

            if (skb2) {
                  loopback = 1;
                  SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
                  if (aarp_send_ddp(dev, skb2,
                                &usat->sat_addr, NULL) == -1)
                        kfree_skb(skb2);
                        /* else queued/sent above in the aarp queue */
            }
      }

      if (dev->flags & IFF_LOOPBACK || loopback) {
            SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
            /* loop back */
            skb_orphan(skb);
            if (ddp->deh_dnode == ATADDR_BCAST) {
                  struct atalk_addr at_lo;

                  at_lo.s_node = 0;
                  at_lo.s_net  = 0;

                  rt = atrtr_find(&at_lo);
                  if (!rt) {
                        kfree_skb(skb);
                        return -ENETUNREACH;
                  }
                  dev = rt->dev;
                  skb->dev = dev;
            }
            ddp_dl->request(ddp_dl, skb, dev->dev_addr);
      } else {
            SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
            if (rt->flags & RTF_GATEWAY) {
                gsat.sat_addr = rt->gateway;
                usat = &gsat;
            }

            if (aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
                  kfree_skb(skb);
            /* else queued/sent above in the aarp queue */
      }
      SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);

      return len;
}

static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                   size_t size, int flags)
{
      struct sock *sk = sock->sk;
      struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
      struct ddpehdr *ddp;
      int copied = 0;
      int offset = 0;
      int err = 0;
      struct sk_buff *skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
                                    flags & MSG_DONTWAIT, &err);
      if (!skb)
            return err;

      /* FIXME: use skb->cb to be able to use shared skbs */
      ddp = ddp_hdr(skb);
      copied = ntohs(ddp->deh_len_hops) & 1023;

      if (sk->sk_type != SOCK_RAW) {
            offset = sizeof(*ddp);
            copied -= offset;
      }

      if (copied > size) {
            copied = size;
            msg->msg_flags |= MSG_TRUNC;
      }
      err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);

      if (!err) {
            if (sat) {
                  sat->sat_family      = AF_APPLETALK;
                  sat->sat_port        = ddp->deh_sport;
                  sat->sat_addr.s_node = ddp->deh_snode;
                  sat->sat_addr.s_net  = ddp->deh_snet;
            }
            msg->msg_namelen = sizeof(*sat);
      }

      skb_free_datagram(sk, skb);   /* Free the datagram. */
      return err ? : copied;
}


/*
 * AppleTalk ioctl calls.
 */
static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
      int rc = -ENOIOCTLCMD;
      struct sock *sk = sock->sk;
      void __user *argp = (void __user *)arg;

      switch (cmd) {
            /* Protocol layer */
            case TIOCOUTQ: {
                  long amount = sk->sk_sndbuf -
                              atomic_read(&sk->sk_wmem_alloc);

                  if (amount < 0)
                        amount = 0;
                  rc = put_user(amount, (int __user *)argp);
                  break;
            }
            case TIOCINQ: {
                  /*
                   * These two are safe on a single CPU system as only
                   * user tasks fiddle here
                   */
                  struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
                  long amount = 0;

                  if (skb)
                        amount = skb->len - sizeof(struct ddpehdr);
                  rc = put_user(amount, (int __user *)argp);
                  break;
            }
            case SIOCGSTAMP:
                  rc = sock_get_timestamp(sk, argp);
                  break;
            case SIOCGSTAMPNS:
                  rc = sock_get_timestampns(sk, argp);
                  break;
            /* Routing */
            case SIOCADDRT:
            case SIOCDELRT:
                  rc = -EPERM;
                  if (capable(CAP_NET_ADMIN))
                        rc = atrtr_ioctl(cmd, argp);
                  break;
            /* Interface */
            case SIOCGIFADDR:
            case SIOCSIFADDR:
            case SIOCGIFBRDADDR:
            case SIOCATALKDIFADDR:
            case SIOCDIFADDR:
            case SIOCSARP:          /* proxy AARP */
            case SIOCDARP:          /* proxy AARP */
                  rtnl_lock();
                  rc = atif_ioctl(cmd, argp);
                  rtnl_unlock();
                  break;
      }

      return rc;
}


#ifdef CONFIG_COMPAT
static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
      /*
       * All Appletalk ioctls except SIOCATALKDIFADDR are standard.  And
       * SIOCATALKDIFADDR is handled by upper layer as well, so there is
       * nothing to do.  Eventually SIOCATALKDIFADDR should be moved
       * here so there is no generic SIOCPROTOPRIVATE translation in the
       * system.
       */
      return -ENOIOCTLCMD;
}
#endif


static struct net_proto_family atalk_family_ops = {
      .family           = PF_APPLETALK,
      .create           = atalk_create,
      .owner            = THIS_MODULE,
};

static const struct proto_ops SOCKOPS_WRAPPED(atalk_dgram_ops) = {
      .family           = PF_APPLETALK,
      .owner            = THIS_MODULE,
      .release    = atalk_release,
      .bind       = atalk_bind,
      .connect    = atalk_connect,
      .socketpair = sock_no_socketpair,
      .accept           = sock_no_accept,
      .getname    = atalk_getname,
      .poll       = datagram_poll,
      .ioctl            = atalk_ioctl,
#ifdef CONFIG_COMPAT
      .compat_ioctl     = atalk_compat_ioctl,
#endif
      .listen           = sock_no_listen,
      .shutdown   = sock_no_shutdown,
      .setsockopt = sock_no_setsockopt,
      .getsockopt = sock_no_getsockopt,
      .sendmsg    = atalk_sendmsg,
      .recvmsg    = atalk_recvmsg,
      .mmap       = sock_no_mmap,
      .sendpage   = sock_no_sendpage,
};

SOCKOPS_WRAP(atalk_dgram, PF_APPLETALK);

static struct notifier_block ddp_notifier = {
      .notifier_call    = ddp_device_event,
};

static struct packet_type ltalk_packet_type = {
      .type       = __constant_htons(ETH_P_LOCALTALK),
      .func       = ltalk_rcv,
};

static struct packet_type ppptalk_packet_type = {
      .type       = __constant_htons(ETH_P_PPPTALK),
      .func       = atalk_rcv,
};

static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };

/* Export symbols for use by drivers when AppleTalk is a module */
EXPORT_SYMBOL(aarp_send_ddp);
EXPORT_SYMBOL(atrtr_get_dev);
EXPORT_SYMBOL(atalk_find_dev_addr);

static char atalk_err_snap[] __initdata =
      KERN_CRIT "Unable to register DDP with SNAP.\n";

/* Called by proto.c on kernel start up */
static int __init atalk_init(void)
{
      int rc = proto_register(&ddp_proto, 0);

      if (rc != 0)
            goto out;

      (void)sock_register(&atalk_family_ops);
      ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
      if (!ddp_dl)
            printk(atalk_err_snap);

      dev_add_pack(&ltalk_packet_type);
      dev_add_pack(&ppptalk_packet_type);

      register_netdevice_notifier(&ddp_notifier);
      aarp_proto_init();
      atalk_proc_init();
      atalk_register_sysctl();
out:
      return rc;
}
module_init(atalk_init);

/*
 * No explicit module reference count manipulation is needed in the
 * protocol. Socket layer sets module reference count for us
 * and interfaces reference counting is done
 * by the network device layer.
 *
 * Ergo, before the AppleTalk module can be removed, all AppleTalk
 * sockets be closed from user space.
 */
static void __exit atalk_exit(void)
{
#ifdef CONFIG_SYSCTL
      atalk_unregister_sysctl();
#endif /* CONFIG_SYSCTL */
      atalk_proc_exit();
      aarp_cleanup_module();  /* General aarp clean-up. */
      unregister_netdevice_notifier(&ddp_notifier);
      dev_remove_pack(&ltalk_packet_type);
      dev_remove_pack(&ppptalk_packet_type);
      unregister_snap_client(ddp_dl);
      sock_unregister(PF_APPLETALK);
      proto_unregister(&ddp_proto);
}
module_exit(atalk_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Cox <Alan.Cox@linux.org>");
MODULE_DESCRIPTION("AppleTalk 0.20\n");
MODULE_ALIAS_NETPROTO(PF_APPLETALK);

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