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af_decnet.c

/*
 * DECnet       An implementation of the DECnet protocol suite for the LINUX
 *              operating system.  DECnet is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              DECnet Socket Layer Interface
 *
 * Authors:     Eduardo Marcelo Serrat <emserrat@geocities.com>
 *              Patrick Caulfield <patrick@pandh.demon.co.uk>
 *
 * Changes:
 *        Steve Whitehouse: Copied from Eduardo Serrat and Patrick Caulfield's
 *                          version of the code. Original copyright preserved
 *                          below.
 *        Steve Whitehouse: Some bug fixes, cleaning up some code to make it
 *                          compatible with my routing layer.
 *        Steve Whitehouse: Merging changes from Eduardo Serrat and Patrick
 *                          Caulfield.
 *        Steve Whitehouse: Further bug fixes, checking module code still works
 *                          with new routing layer.
 *        Steve Whitehouse: Additional set/get_sockopt() calls.
 *        Steve Whitehouse: Fixed TIOCINQ ioctl to be same as Eduardo's new
 *                          code.
 *        Steve Whitehouse: recvmsg() changed to try and behave in a POSIX like
 *                          way. Didn't manage it entirely, but its better.
 *        Steve Whitehouse: ditto for sendmsg().
 *        Steve Whitehouse: A selection of bug fixes to various things.
 *        Steve Whitehouse: Added TIOCOUTQ ioctl.
 *        Steve Whitehouse: Fixes to username2sockaddr & sockaddr2username.
 *        Steve Whitehouse: Fixes to connect() error returns.
 *       Patrick Caulfield: Fixes to delayed acceptance logic.
 *         David S. Miller: New socket locking
 *        Steve Whitehouse: Socket list hashing/locking
 *         Arnaldo C. Melo: use capable, not suser
 *        Steve Whitehouse: Removed unused code. Fix to use sk->allocation
 *                          when required.
 *       Patrick Caulfield: /proc/net/decnet now has object name/number
 *        Steve Whitehouse: Fixed local port allocation, hashed sk list
 *          Matthew Wilcox: Fixes for dn_ioctl()
 *        Steve Whitehouse: New connect/accept logic to allow timeouts and
 *                          prepare for sendpage etc.
 */


/******************************************************************************
    (c) 1995-1998 E.M. Serrat       emserrat@geocities.com

    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
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

HISTORY:

Version           Kernel     Date       Author/Comments
-------           ------     ----       ---------------
Version 0.0.1     2.0.30    01-dic-97     Eduardo Marcelo Serrat
                              (emserrat@geocities.com)

                              First Development of DECnet Socket La-
                              yer for Linux. Only supports outgoing
                              connections.

Version 0.0.2       2.1.105   20-jun-98   Patrick J. Caulfield
                              (patrick@pandh.demon.co.uk)

                              Port to new kernel development version.

Version 0.0.3     2.1.106   25-jun-98   Eduardo Marcelo Serrat
                              (emserrat@geocities.com)
                              _
                              Added support for incoming connections
                              so we can start developing server apps
                              on Linux.
                              -
                              Module Support
Version 0.0.4     2.1.109   21-jul-98   Eduardo Marcelo Serrat
                               (emserrat@geocities.com)
                               _
                              Added support for X11R6.4. Now we can
                              use DECnet transport for X on Linux!!!
                               -
Version 0.0.5    2.1.110   01-aug-98   Eduardo Marcelo Serrat
                               (emserrat@geocities.com)
                               Removed bugs on flow control
                               Removed bugs on incoming accessdata
                               order
                               -
Version 0.0.6    2.1.110   07-aug-98   Eduardo Marcelo Serrat
                               dn_recvmsg fixes

                              Patrick J. Caulfield
                               dn_bind fixes
*******************************************************************************/

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/slab.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 <linux/inet.h>
#include <linux/route.h>
#include <linux/netfilter.h>
#include <linux/seq_file.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/flow.h>
#include <asm/system.h>
#include <asm/ioctls.h>
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <net/net_namespace.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/fib_rules.h>
#include <net/dn.h>
#include <net/dn_nsp.h>
#include <net/dn_dev.h>
#include <net/dn_route.h>
#include <net/dn_fib.h>
#include <net/dn_neigh.h>

struct dn_sock {
      struct sock sk;
      struct dn_scp scp;
};

static void dn_keepalive(struct sock *sk);

#define DN_SK_HASH_SHIFT 8
#define DN_SK_HASH_SIZE (1 << DN_SK_HASH_SHIFT)
#define DN_SK_HASH_MASK (DN_SK_HASH_SIZE - 1)


static const struct proto_ops dn_proto_ops;
static DEFINE_RWLOCK(dn_hash_lock);
static struct hlist_head dn_sk_hash[DN_SK_HASH_SIZE];
static struct hlist_head dn_wild_sk;
static atomic_t decnet_memory_allocated;

static int __dn_setsockopt(struct socket *sock, int level, int optname, char __user *optval, int optlen, int flags);
static int __dn_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen, int flags);

static struct hlist_head *dn_find_list(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);

      if (scp->addr.sdn_flags & SDF_WILD)
            return hlist_empty(&dn_wild_sk) ? &dn_wild_sk : NULL;

      return &dn_sk_hash[dn_ntohs(scp->addrloc) & DN_SK_HASH_MASK];
}

/*
 * Valid ports are those greater than zero and not already in use.
 */
static int check_port(__le16 port)
{
      struct sock *sk;
      struct hlist_node *node;

      if (port == 0)
            return -1;

      sk_for_each(sk, node, &dn_sk_hash[dn_ntohs(port) & DN_SK_HASH_MASK]) {
            struct dn_scp *scp = DN_SK(sk);
            if (scp->addrloc == port)
                  return -1;
      }
      return 0;
}

static unsigned short port_alloc(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);
static unsigned short port = 0x2000;
      unsigned short i_port = port;

      while(check_port(dn_htons(++port)) != 0) {
            if (port == i_port)
                  return 0;
      }

      scp->addrloc = dn_htons(port);

      return 1;
}

/*
 * Since this is only ever called from user
 * level, we don't need a write_lock() version
 * of this.
 */
static int dn_hash_sock(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);
      struct hlist_head *list;
      int rv = -EUSERS;

      BUG_ON(sk_hashed(sk));

      write_lock_bh(&dn_hash_lock);

      if (!scp->addrloc && !port_alloc(sk))
            goto out;

      rv = -EADDRINUSE;
      if ((list = dn_find_list(sk)) == NULL)
            goto out;

      sk_add_node(sk, list);
      rv = 0;
out:
      write_unlock_bh(&dn_hash_lock);
      return rv;
}

static void dn_unhash_sock(struct sock *sk)
{
      write_lock(&dn_hash_lock);
      sk_del_node_init(sk);
      write_unlock(&dn_hash_lock);
}

static void dn_unhash_sock_bh(struct sock *sk)
{
      write_lock_bh(&dn_hash_lock);
      sk_del_node_init(sk);
      write_unlock_bh(&dn_hash_lock);
}

static struct hlist_head *listen_hash(struct sockaddr_dn *addr)
{
      int i;
      unsigned hash = addr->sdn_objnum;

      if (hash == 0) {
            hash = addr->sdn_objnamel;
            for(i = 0; i < dn_ntohs(addr->sdn_objnamel); i++) {
                  hash ^= addr->sdn_objname[i];
                  hash ^= (hash << 3);
            }
      }

      return &dn_sk_hash[hash & DN_SK_HASH_MASK];
}

/*
 * Called to transform a socket from bound (i.e. with a local address)
 * into a listening socket (doesn't need a local port number) and rehashes
 * based upon the object name/number.
 */
static void dn_rehash_sock(struct sock *sk)
{
      struct hlist_head *list;
      struct dn_scp *scp = DN_SK(sk);

      if (scp->addr.sdn_flags & SDF_WILD)
            return;

      write_lock_bh(&dn_hash_lock);
      sk_del_node_init(sk);
      DN_SK(sk)->addrloc = 0;
      list = listen_hash(&DN_SK(sk)->addr);
      sk_add_node(sk, list);
      write_unlock_bh(&dn_hash_lock);
}

int dn_sockaddr2username(struct sockaddr_dn *sdn, unsigned char *buf, unsigned char type)
{
      int len = 2;

      *buf++ = type;

      switch(type) {
            case 0:
                  *buf++ = sdn->sdn_objnum;
                  break;
            case 1:
                  *buf++ = 0;
                  *buf++ = dn_ntohs(sdn->sdn_objnamel);
                  memcpy(buf, sdn->sdn_objname, dn_ntohs(sdn->sdn_objnamel));
                  len = 3 + dn_ntohs(sdn->sdn_objnamel);
                  break;
            case 2:
                  memset(buf, 0, 5);
                  buf += 5;
                  *buf++ = dn_ntohs(sdn->sdn_objnamel);
                  memcpy(buf, sdn->sdn_objname, dn_ntohs(sdn->sdn_objnamel));
                  len = 7 + dn_ntohs(sdn->sdn_objnamel);
                  break;
      }

      return len;
}

/*
 * On reception of usernames, we handle types 1 and 0 for destination
 * addresses only. Types 2 and 4 are used for source addresses, but the
 * UIC, GIC are ignored and they are both treated the same way. Type 3
 * is never used as I've no idea what its purpose might be or what its
 * format is.
 */
int dn_username2sockaddr(unsigned char *data, int len, struct sockaddr_dn *sdn, unsigned char *fmt)
{
      unsigned char type;
      int size = len;
      int namel = 12;

      sdn->sdn_objnum = 0;
      sdn->sdn_objnamel = dn_htons(0);
      memset(sdn->sdn_objname, 0, DN_MAXOBJL);

      if (len < 2)
            return -1;

      len -= 2;
      *fmt = *data++;
      type = *data++;

      switch(*fmt) {
            case 0:
                  sdn->sdn_objnum = type;
                  return 2;
            case 1:
                  namel = 16;
                  break;
            case 2:
                  len  -= 4;
                  data += 4;
                  break;
            case 4:
                  len  -= 8;
                  data += 8;
                  break;
            default:
                  return -1;
      }

      len -= 1;

      if (len < 0)
            return -1;

      sdn->sdn_objnamel = dn_htons(*data++);
      len -= dn_ntohs(sdn->sdn_objnamel);

      if ((len < 0) || (dn_ntohs(sdn->sdn_objnamel) > namel))
            return -1;

      memcpy(sdn->sdn_objname, data, dn_ntohs(sdn->sdn_objnamel));

      return size - len;
}

struct sock *dn_sklist_find_listener(struct sockaddr_dn *addr)
{
      struct hlist_head *list = listen_hash(addr);
      struct hlist_node *node;
      struct sock *sk;

      read_lock(&dn_hash_lock);
      sk_for_each(sk, node, list) {
            struct dn_scp *scp = DN_SK(sk);
            if (sk->sk_state != TCP_LISTEN)
                  continue;
            if (scp->addr.sdn_objnum) {
                  if (scp->addr.sdn_objnum != addr->sdn_objnum)
                        continue;
            } else {
                  if (addr->sdn_objnum)
                        continue;
                  if (scp->addr.sdn_objnamel != addr->sdn_objnamel)
                        continue;
                  if (memcmp(scp->addr.sdn_objname, addr->sdn_objname, dn_ntohs(addr->sdn_objnamel)) != 0)
                        continue;
            }
            sock_hold(sk);
            read_unlock(&dn_hash_lock);
            return sk;
      }

      sk = sk_head(&dn_wild_sk);
      if (sk) {
            if (sk->sk_state == TCP_LISTEN)
                  sock_hold(sk);
            else
                  sk = NULL;
      }

      read_unlock(&dn_hash_lock);
      return sk;
}

struct sock *dn_find_by_skb(struct sk_buff *skb)
{
      struct dn_skb_cb *cb = DN_SKB_CB(skb);
      struct sock *sk;
      struct hlist_node *node;
      struct dn_scp *scp;

      read_lock(&dn_hash_lock);
      sk_for_each(sk, node, &dn_sk_hash[dn_ntohs(cb->dst_port) & DN_SK_HASH_MASK]) {
            scp = DN_SK(sk);
            if (cb->src != dn_saddr2dn(&scp->peer))
                  continue;
            if (cb->dst_port != scp->addrloc)
                  continue;
            if (scp->addrrem && (cb->src_port != scp->addrrem))
                  continue;
            sock_hold(sk);
            goto found;
      }
      sk = NULL;
found:
      read_unlock(&dn_hash_lock);
      return sk;
}



static void dn_destruct(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);

      skb_queue_purge(&scp->data_xmit_queue);
      skb_queue_purge(&scp->other_xmit_queue);
      skb_queue_purge(&scp->other_receive_queue);

      dst_release(xchg(&sk->sk_dst_cache, NULL));
}

static int dn_memory_pressure;

static void dn_enter_memory_pressure(void)
{
      if (!dn_memory_pressure) {
            dn_memory_pressure = 1;
      }
}

static struct proto dn_proto = {
      .name             = "NSP",
      .owner                  = THIS_MODULE,
      .enter_memory_pressure  = dn_enter_memory_pressure,
      .memory_pressure  = &dn_memory_pressure,
      .memory_allocated = &decnet_memory_allocated,
      .sysctl_mem       = sysctl_decnet_mem,
      .sysctl_wmem            = sysctl_decnet_wmem,
      .sysctl_rmem            = sysctl_decnet_rmem,
      .max_header       = DN_MAX_NSP_DATA_HEADER + 64,
      .obj_size         = sizeof(struct dn_sock),
};

static struct sock *dn_alloc_sock(struct net *net, struct socket *sock, gfp_t gfp)
{
      struct dn_scp *scp;
      struct sock *sk = sk_alloc(net, PF_DECnet, gfp, &dn_proto);

      if  (!sk)
            goto out;

      if (sock)
            sock->ops = &dn_proto_ops;
      sock_init_data(sock, sk);

      sk->sk_backlog_rcv = dn_nsp_backlog_rcv;
      sk->sk_destruct    = dn_destruct;
      sk->sk_no_check    = 1;
      sk->sk_family      = PF_DECnet;
      sk->sk_protocol    = 0;
      sk->sk_allocation  = gfp;
      sk->sk_sndbuf        = sysctl_decnet_wmem[1];
      sk->sk_rcvbuf        = sysctl_decnet_rmem[1];

      /* Initialization of DECnet Session Control Port            */
      scp = DN_SK(sk);
      scp->state  = DN_O;           /* Open                 */
      scp->numdat = 1;        /* Next data seg to tx  */
      scp->numoth = 1;        /* Next oth data to tx  */
      scp->ackxmt_dat = 0;          /* Last data seg ack'ed */
      scp->ackxmt_oth = 0;          /* Last oth data ack'ed */
      scp->ackrcv_dat = 0;          /* Highest data ack recv*/
      scp->ackrcv_oth = 0;          /* Last oth data ack rec*/
      scp->flowrem_sw = DN_SEND;
      scp->flowloc_sw = DN_SEND;
      scp->flowrem_dat = 0;
      scp->flowrem_oth = 1;
      scp->flowloc_dat = 0;
      scp->flowloc_oth = 1;
      scp->services_rem = 0;
      scp->services_loc = 1 | NSP_FC_NONE;
      scp->info_rem = 0;
      scp->info_loc = 0x03; /* NSP version 4.1 */
      scp->segsize_rem = 230 - DN_MAX_NSP_DATA_HEADER; /* Default: Updated by remote segsize */
      scp->nonagle = 0;
      scp->multi_ireq = 1;
      scp->accept_mode = ACC_IMMED;
      scp->addr.sdn_family    = AF_DECnet;
      scp->peer.sdn_family    = AF_DECnet;
      scp->accessdata.acc_accl = 5;
      memcpy(scp->accessdata.acc_acc, "LINUX", 5);

      scp->max_window   = NSP_MAX_WINDOW;
      scp->snd_window   = NSP_MIN_WINDOW;
      scp->nsp_srtt     = NSP_INITIAL_SRTT;
      scp->nsp_rttvar   = NSP_INITIAL_RTTVAR;
      scp->nsp_rxtshift = 0;

      skb_queue_head_init(&scp->data_xmit_queue);
      skb_queue_head_init(&scp->other_xmit_queue);
      skb_queue_head_init(&scp->other_receive_queue);

      scp->persist = 0;
      scp->persist_fxn = NULL;
      scp->keepalive = 10 * HZ;
      scp->keepalive_fxn = dn_keepalive;

      init_timer(&scp->delack_timer);
      scp->delack_pending = 0;
      scp->delack_fxn = dn_nsp_delayed_ack;

      dn_start_slow_timer(sk);
out:
      return sk;
}

/*
 * Keepalive timer.
 * FIXME: Should respond to SO_KEEPALIVE etc.
 */
static void dn_keepalive(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);

      /*
       * By checking the other_data transmit queue is empty
       * we are double checking that we are not sending too
       * many of these keepalive frames.
       */
      if (skb_queue_empty(&scp->other_xmit_queue))
            dn_nsp_send_link(sk, DN_NOCHANGE, 0);
}


/*
 * Timer for shutdown/destroyed sockets.
 * When socket is dead & no packets have been sent for a
 * certain amount of time, they are removed by this
 * routine. Also takes care of sending out DI & DC
 * frames at correct times.
 */
int dn_destroy_timer(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);

      scp->persist = dn_nsp_persist(sk);

      switch(scp->state) {
            case DN_DI:
                  dn_nsp_send_disc(sk, NSP_DISCINIT, 0, GFP_ATOMIC);
                  if (scp->nsp_rxtshift >= decnet_di_count)
                        scp->state = DN_CN;
                  return 0;

            case DN_DR:
                  dn_nsp_send_disc(sk, NSP_DISCINIT, 0, GFP_ATOMIC);
                  if (scp->nsp_rxtshift >= decnet_dr_count)
                        scp->state = DN_DRC;
                  return 0;

            case DN_DN:
                  if (scp->nsp_rxtshift < decnet_dn_count) {
                        /* printk(KERN_DEBUG "dn_destroy_timer: DN\n"); */
                        dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
                        return 0;
                  }
      }

      scp->persist = (HZ * decnet_time_wait);

      if (sk->sk_socket)
            return 0;

      if ((jiffies - scp->stamp) >= (HZ * decnet_time_wait)) {
            dn_unhash_sock(sk);
            sock_put(sk);
            return 1;
      }

      return 0;
}

static void dn_destroy_sock(struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);

      scp->nsp_rxtshift = 0; /* reset back off */

      if (sk->sk_socket) {
            if (sk->sk_socket->state != SS_UNCONNECTED)
                  sk->sk_socket->state = SS_DISCONNECTING;
      }

      sk->sk_state = TCP_CLOSE;

      switch(scp->state) {
            case DN_DN:
                  dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC,
                               sk->sk_allocation);
                  scp->persist_fxn = dn_destroy_timer;
                  scp->persist = dn_nsp_persist(sk);
                  break;
            case DN_CR:
                  scp->state = DN_DR;
                  goto disc_reject;
            case DN_RUN:
                  scp->state = DN_DI;
            case DN_DI:
            case DN_DR:
disc_reject:
                  dn_nsp_send_disc(sk, NSP_DISCINIT, 0, sk->sk_allocation);
            case DN_NC:
            case DN_NR:
            case DN_RJ:
            case DN_DIC:
            case DN_CN:
            case DN_DRC:
            case DN_CI:
            case DN_CD:
                  scp->persist_fxn = dn_destroy_timer;
                  scp->persist = dn_nsp_persist(sk);
                  break;
            default:
                  printk(KERN_DEBUG "DECnet: dn_destroy_sock passed socket in invalid state\n");
            case DN_O:
                  dn_stop_slow_timer(sk);

                  dn_unhash_sock_bh(sk);
                  sock_put(sk);

                  break;
      }
}

char *dn_addr2asc(__u16 addr, char *buf)
{
      unsigned short node, area;

      node = addr & 0x03ff;
      area = addr >> 10;
      sprintf(buf, "%hd.%hd", area, node);

      return buf;
}



static int dn_create(struct net *net, struct socket *sock, int protocol)
{
      struct sock *sk;

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

      switch(sock->type) {
            case SOCK_SEQPACKET:
                  if (protocol != DNPROTO_NSP)
                        return -EPROTONOSUPPORT;
                  break;
            case SOCK_STREAM:
                  break;
            default:
                  return -ESOCKTNOSUPPORT;
      }


      if ((sk = dn_alloc_sock(net, sock, GFP_KERNEL)) == NULL)
            return -ENOBUFS;

      sk->sk_protocol = protocol;

      return 0;
}


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

      if (sk) {
            sock_orphan(sk);
            sock_hold(sk);
            lock_sock(sk);
            dn_destroy_sock(sk);
            release_sock(sk);
            sock_put(sk);
      }

      return 0;
}

static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      struct sockaddr_dn *saddr = (struct sockaddr_dn *)uaddr;
      struct net_device *dev, *ldev;
      int rv;

      if (addr_len != sizeof(struct sockaddr_dn))
            return -EINVAL;

      if (saddr->sdn_family != AF_DECnet)
            return -EINVAL;

      if (dn_ntohs(saddr->sdn_nodeaddrl) && (dn_ntohs(saddr->sdn_nodeaddrl) != 2))
            return -EINVAL;

      if (dn_ntohs(saddr->sdn_objnamel) > DN_MAXOBJL)
            return -EINVAL;

      if (saddr->sdn_flags & ~SDF_WILD)
            return -EINVAL;

      if (!capable(CAP_NET_BIND_SERVICE) && (saddr->sdn_objnum ||
          (saddr->sdn_flags & SDF_WILD)))
            return -EACCES;

      if (!(saddr->sdn_flags & SDF_WILD)) {
            if (dn_ntohs(saddr->sdn_nodeaddrl)) {
                  read_lock(&dev_base_lock);
                  ldev = NULL;
                  for_each_netdev(&init_net, dev) {
                        if (!dev->dn_ptr)
                              continue;
                        if (dn_dev_islocal(dev, dn_saddr2dn(saddr))) {
                              ldev = dev;
                              break;
                        }
                  }
                  read_unlock(&dev_base_lock);
                  if (ldev == NULL)
                        return -EADDRNOTAVAIL;
            }
      }

      rv = -EINVAL;
      lock_sock(sk);
      if (sock_flag(sk, SOCK_ZAPPED)) {
            memcpy(&scp->addr, saddr, addr_len);
            sock_reset_flag(sk, SOCK_ZAPPED);

            rv = dn_hash_sock(sk);
            if (rv)
                  sock_set_flag(sk, SOCK_ZAPPED);
      }
      release_sock(sk);

      return rv;
}


static int dn_auto_bind(struct socket *sock)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      int rv;

      sock_reset_flag(sk, SOCK_ZAPPED);

      scp->addr.sdn_flags  = 0;
      scp->addr.sdn_objnum = 0;

      /*
       * This stuff is to keep compatibility with Eduardo's
       * patch. I hope I can dispense with it shortly...
       */
      if ((scp->accessdata.acc_accl != 0) &&
            (scp->accessdata.acc_accl <= 12)) {

            scp->addr.sdn_objnamel = dn_htons(scp->accessdata.acc_accl);
            memcpy(scp->addr.sdn_objname, scp->accessdata.acc_acc, dn_ntohs(scp->addr.sdn_objnamel));

            scp->accessdata.acc_accl = 0;
            memset(scp->accessdata.acc_acc, 0, 40);
      }
      /* End of compatibility stuff */

      scp->addr.sdn_add.a_len = dn_htons(2);
      rv = dn_dev_bind_default((__le16 *)scp->addr.sdn_add.a_addr);
      if (rv == 0) {
            rv = dn_hash_sock(sk);
            if (rv)
                  sock_set_flag(sk, SOCK_ZAPPED);
      }

      return rv;
}

static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
{
      struct dn_scp *scp = DN_SK(sk);
      DEFINE_WAIT(wait);
      int err;

      if (scp->state != DN_CR)
            return -EINVAL;

      scp->state = DN_CC;
      scp->segsize_loc = dst_metric(__sk_dst_get(sk), RTAX_ADVMSS);
      dn_send_conn_conf(sk, allocation);

      prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      for(;;) {
            release_sock(sk);
            if (scp->state == DN_CC)
                  *timeo = schedule_timeout(*timeo);
            lock_sock(sk);
            err = 0;
            if (scp->state == DN_RUN)
                  break;
            err = sock_error(sk);
            if (err)
                  break;
            err = sock_intr_errno(*timeo);
            if (signal_pending(current))
                  break;
            err = -EAGAIN;
            if (!*timeo)
                  break;
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      }
      finish_wait(sk->sk_sleep, &wait);
      if (err == 0) {
            sk->sk_socket->state = SS_CONNECTED;
      } else if (scp->state != DN_CC) {
            sk->sk_socket->state = SS_UNCONNECTED;
      }
      return err;
}

static int dn_wait_run(struct sock *sk, long *timeo)
{
      struct dn_scp *scp = DN_SK(sk);
      DEFINE_WAIT(wait);
      int err = 0;

      if (scp->state == DN_RUN)
            goto out;

      if (!*timeo)
            return -EALREADY;

      prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      for(;;) {
            release_sock(sk);
            if (scp->state == DN_CI || scp->state == DN_CC)
                  *timeo = schedule_timeout(*timeo);
            lock_sock(sk);
            err = 0;
            if (scp->state == DN_RUN)
                  break;
            err = sock_error(sk);
            if (err)
                  break;
            err = sock_intr_errno(*timeo);
            if (signal_pending(current))
                  break;
            err = -ETIMEDOUT;
            if (!*timeo)
                  break;
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      }
      finish_wait(sk->sk_sleep, &wait);
out:
      if (err == 0) {
            sk->sk_socket->state = SS_CONNECTED;
      } else if (scp->state != DN_CI && scp->state != DN_CC) {
            sk->sk_socket->state = SS_UNCONNECTED;
      }
      return err;
}

static int __dn_connect(struct sock *sk, struct sockaddr_dn *addr, int addrlen, long *timeo, int flags)
{
      struct socket *sock = sk->sk_socket;
      struct dn_scp *scp = DN_SK(sk);
      int err = -EISCONN;
      struct flowi fl;

      if (sock->state == SS_CONNECTED)
            goto out;

      if (sock->state == SS_CONNECTING) {
            err = 0;
            if (scp->state == DN_RUN) {
                  sock->state = SS_CONNECTED;
                  goto out;
            }
            err = -ECONNREFUSED;
            if (scp->state != DN_CI && scp->state != DN_CC) {
                  sock->state = SS_UNCONNECTED;
                  goto out;
            }
            return dn_wait_run(sk, timeo);
      }

      err = -EINVAL;
      if (scp->state != DN_O)
            goto out;

      if (addr == NULL || addrlen != sizeof(struct sockaddr_dn))
            goto out;
      if (addr->sdn_family != AF_DECnet)
            goto out;
      if (addr->sdn_flags & SDF_WILD)
            goto out;

      if (sock_flag(sk, SOCK_ZAPPED)) {
            err = dn_auto_bind(sk->sk_socket);
            if (err)
                  goto out;
      }

      memcpy(&scp->peer, addr, sizeof(struct sockaddr_dn));

      err = -EHOSTUNREACH;
      memset(&fl, 0, sizeof(fl));
      fl.oif = sk->sk_bound_dev_if;
      fl.fld_dst = dn_saddr2dn(&scp->peer);
      fl.fld_src = dn_saddr2dn(&scp->addr);
      dn_sk_ports_copy(&fl, scp);
      fl.proto = DNPROTO_NSP;
      if (dn_route_output_sock(&sk->sk_dst_cache, &fl, sk, flags) < 0)
            goto out;
      sk->sk_route_caps = sk->sk_dst_cache->dev->features;
      sock->state = SS_CONNECTING;
      scp->state = DN_CI;
      scp->segsize_loc = dst_metric(sk->sk_dst_cache, RTAX_ADVMSS);

      dn_nsp_send_conninit(sk, NSP_CI);
      err = -EINPROGRESS;
      if (*timeo) {
            err = dn_wait_run(sk, timeo);
      }
out:
      return err;
}

static int dn_connect(struct socket *sock, struct sockaddr *uaddr, int addrlen, int flags)
{
      struct sockaddr_dn *addr = (struct sockaddr_dn *)uaddr;
      struct sock *sk = sock->sk;
      int err;
      long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);

      lock_sock(sk);
      err = __dn_connect(sk, addr, addrlen, &timeo, 0);
      release_sock(sk);

      return err;
}

static inline int dn_check_state(struct sock *sk, struct sockaddr_dn *addr, int addrlen, long *timeo, int flags)
{
      struct dn_scp *scp = DN_SK(sk);

      switch(scp->state) {
            case DN_RUN:
                  return 0;
            case DN_CR:
                  return dn_confirm_accept(sk, timeo, sk->sk_allocation);
            case DN_CI:
            case DN_CC:
                  return dn_wait_run(sk, timeo);
            case DN_O:
                  return __dn_connect(sk, addr, addrlen, timeo, flags);
      }

      return -EINVAL;
}


static void dn_access_copy(struct sk_buff *skb, struct accessdata_dn *acc)
{
      unsigned char *ptr = skb->data;

      acc->acc_userl = *ptr++;
      memcpy(&acc->acc_user, ptr, acc->acc_userl);
      ptr += acc->acc_userl;

      acc->acc_passl = *ptr++;
      memcpy(&acc->acc_pass, ptr, acc->acc_passl);
      ptr += acc->acc_passl;

      acc->acc_accl = *ptr++;
      memcpy(&acc->acc_acc, ptr, acc->acc_accl);

      skb_pull(skb, acc->acc_accl + acc->acc_passl + acc->acc_userl + 3);

}

static void dn_user_copy(struct sk_buff *skb, struct optdata_dn *opt)
{
      unsigned char *ptr = skb->data;
      u16 len = *ptr++; /* yes, it's 8bit on the wire */

      BUG_ON(len > 16); /* we've checked the contents earlier */
      opt->opt_optl   = dn_htons(len);
      opt->opt_status = 0;
      memcpy(opt->opt_data, ptr, len);
      skb_pull(skb, len + 1);
}

static struct sk_buff *dn_wait_for_connect(struct sock *sk, long *timeo)
{
      DEFINE_WAIT(wait);
      struct sk_buff *skb = NULL;
      int err = 0;

      prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      for(;;) {
            release_sock(sk);
            skb = skb_dequeue(&sk->sk_receive_queue);
            if (skb == NULL) {
                  *timeo = schedule_timeout(*timeo);
                  skb = skb_dequeue(&sk->sk_receive_queue);
            }
            lock_sock(sk);
            if (skb != NULL)
                  break;
            err = -EINVAL;
            if (sk->sk_state != TCP_LISTEN)
                  break;
            err = sock_intr_errno(*timeo);
            if (signal_pending(current))
                  break;
            err = -EAGAIN;
            if (!*timeo)
                  break;
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      }
      finish_wait(sk->sk_sleep, &wait);

      return skb == NULL ? ERR_PTR(err) : skb;
}

static int dn_accept(struct socket *sock, struct socket *newsock, int flags)
{
      struct sock *sk = sock->sk, *newsk;
      struct sk_buff *skb = NULL;
      struct dn_skb_cb *cb;
      unsigned char menuver;
      int err = 0;
      unsigned char type;
      long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

      lock_sock(sk);

      if (sk->sk_state != TCP_LISTEN || DN_SK(sk)->state != DN_O) {
            release_sock(sk);
            return -EINVAL;
      }

      skb = skb_dequeue(&sk->sk_receive_queue);
      if (skb == NULL) {
            skb = dn_wait_for_connect(sk, &timeo);
            if (IS_ERR(skb)) {
                  release_sock(sk);
                  return PTR_ERR(skb);
            }
      }

      cb = DN_SKB_CB(skb);
      sk->sk_ack_backlog--;
      newsk = dn_alloc_sock(sk->sk_net, newsock, sk->sk_allocation);
      if (newsk == NULL) {
            release_sock(sk);
            kfree_skb(skb);
            return -ENOBUFS;
      }
      release_sock(sk);

      dst_release(xchg(&newsk->sk_dst_cache, skb->dst));
      skb->dst = NULL;

      DN_SK(newsk)->state        = DN_CR;
      DN_SK(newsk)->addrrem      = cb->src_port;
      DN_SK(newsk)->services_rem = cb->services;
      DN_SK(newsk)->info_rem     = cb->info;
      DN_SK(newsk)->segsize_rem  = cb->segsize;
      DN_SK(newsk)->accept_mode  = DN_SK(sk)->accept_mode;

      if (DN_SK(newsk)->segsize_rem < 230)
            DN_SK(newsk)->segsize_rem = 230;

      if ((DN_SK(newsk)->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
            DN_SK(newsk)->max_window = decnet_no_fc_max_cwnd;

      newsk->sk_state  = TCP_LISTEN;
      memcpy(&(DN_SK(newsk)->addr), &(DN_SK(sk)->addr), sizeof(struct sockaddr_dn));

      /*
       * If we are listening on a wild socket, we don't want
       * the newly created socket on the wrong hash queue.
       */
      DN_SK(newsk)->addr.sdn_flags &= ~SDF_WILD;

      skb_pull(skb, dn_username2sockaddr(skb->data, skb->len, &(DN_SK(newsk)->addr), &type));
      skb_pull(skb, dn_username2sockaddr(skb->data, skb->len, &(DN_SK(newsk)->peer), &type));
      *(__le16 *)(DN_SK(newsk)->peer.sdn_add.a_addr) = cb->src;
      *(__le16 *)(DN_SK(newsk)->addr.sdn_add.a_addr) = cb->dst;

      menuver = *skb->data;
      skb_pull(skb, 1);

      if (menuver & DN_MENUVER_ACC)
            dn_access_copy(skb, &(DN_SK(newsk)->accessdata));

      if (menuver & DN_MENUVER_USR)
            dn_user_copy(skb, &(DN_SK(newsk)->conndata_in));

      if (menuver & DN_MENUVER_PRX)
            DN_SK(newsk)->peer.sdn_flags |= SDF_PROXY;

      if (menuver & DN_MENUVER_UIC)
            DN_SK(newsk)->peer.sdn_flags |= SDF_UICPROXY;

      kfree_skb(skb);

      memcpy(&(DN_SK(newsk)->conndata_out), &(DN_SK(sk)->conndata_out),
            sizeof(struct optdata_dn));
      memcpy(&(DN_SK(newsk)->discdata_out), &(DN_SK(sk)->discdata_out),
            sizeof(struct optdata_dn));

      lock_sock(newsk);
      err = dn_hash_sock(newsk);
      if (err == 0) {
            sock_reset_flag(newsk, SOCK_ZAPPED);
            dn_send_conn_ack(newsk);

            /*
             * Here we use sk->sk_allocation since although the conn conf is
             * for the newsk, the context is the old socket.
             */
            if (DN_SK(newsk)->accept_mode == ACC_IMMED)
                  err = dn_confirm_accept(newsk, &timeo,
                                    sk->sk_allocation);
      }
      release_sock(newsk);
      return err;
}


static int dn_getname(struct socket *sock, struct sockaddr *uaddr,int *uaddr_len,int peer)
{
      struct sockaddr_dn *sa = (struct sockaddr_dn *)uaddr;
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);

      *uaddr_len = sizeof(struct sockaddr_dn);

      lock_sock(sk);

      if (peer) {
            if ((sock->state != SS_CONNECTED &&
                 sock->state != SS_CONNECTING) &&
                scp->accept_mode == ACC_IMMED) {
                  release_sock(sk);
                  return -ENOTCONN;
            }

            memcpy(sa, &scp->peer, sizeof(struct sockaddr_dn));
      } else {
            memcpy(sa, &scp->addr, sizeof(struct sockaddr_dn));
      }

      release_sock(sk);

      return 0;
}


static unsigned int dn_poll(struct file *file, struct socket *sock, poll_table  *wait)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      int mask = datagram_poll(file, sock, wait);

      if (!skb_queue_empty(&scp->other_receive_queue))
            mask |= POLLRDBAND;

      return mask;
}

static int dn_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      int err = -EOPNOTSUPP;
      long amount = 0;
      struct sk_buff *skb;
      int val;

      switch(cmd)
      {
      case SIOCGIFADDR:
      case SIOCSIFADDR:
            return dn_dev_ioctl(cmd, (void __user *)arg);

      case SIOCATMARK:
            lock_sock(sk);
            val = !skb_queue_empty(&scp->other_receive_queue);
            if (scp->state != DN_RUN)
                  val = -ENOTCONN;
            release_sock(sk);
            return val;

      case TIOCOUTQ:
            amount = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
            if (amount < 0)
                  amount = 0;
            err = put_user(amount, (int __user *)arg);
            break;

      case TIOCINQ:
            lock_sock(sk);
            if ((skb = skb_peek(&scp->other_receive_queue)) != NULL) {
                  amount = skb->len;
            } else {
                  struct sk_buff *skb = sk->sk_receive_queue.next;
                  for(;;) {
                        if (skb ==
                            (struct sk_buff *)&sk->sk_receive_queue)
                              break;
                        amount += skb->len;
                        skb = skb->next;
                  }
            }
            release_sock(sk);
            err = put_user(amount, (int __user *)arg);
            break;

      default:
            err = -ENOIOCTLCMD;
            break;
      }

      return err;
}

static int dn_listen(struct socket *sock, int backlog)
{
      struct sock *sk = sock->sk;
      int err = -EINVAL;

      lock_sock(sk);

      if (sock_flag(sk, SOCK_ZAPPED))
            goto out;

      if ((DN_SK(sk)->state != DN_O) || (sk->sk_state == TCP_LISTEN))
            goto out;

      sk->sk_max_ack_backlog = backlog;
      sk->sk_ack_backlog     = 0;
      sk->sk_state           = TCP_LISTEN;
      err                 = 0;
      dn_rehash_sock(sk);

out:
      release_sock(sk);

      return err;
}


static int dn_shutdown(struct socket *sock, int how)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      int err = -ENOTCONN;

      lock_sock(sk);

      if (sock->state == SS_UNCONNECTED)
            goto out;

      err = 0;
      if (sock->state == SS_DISCONNECTING)
            goto out;

      err = -EINVAL;
      if (scp->state == DN_O)
            goto out;

      if (how != SHUTDOWN_MASK)
            goto out;

      sk->sk_shutdown = how;
      dn_destroy_sock(sk);
      err = 0;

out:
      release_sock(sk);

      return err;
}

static int dn_setsockopt(struct socket *sock, int level, int optname, char __user *optval, int optlen)
{
      struct sock *sk = sock->sk;
      int err;

      lock_sock(sk);
      err = __dn_setsockopt(sock, level, optname, optval, optlen, 0);
      release_sock(sk);

      return err;
}

static int __dn_setsockopt(struct socket *sock, int level,int optname, char __user *optval, int optlen, int flags)
{
      struct      sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      long timeo;
      union {
            struct optdata_dn opt;
            struct accessdata_dn acc;
            int mode;
            unsigned long win;
            int val;
            unsigned char services;
            unsigned char info;
      } u;
      int err;

      if (optlen && !optval)
            return -EINVAL;

      if (optlen > sizeof(u))
            return -EINVAL;

      if (copy_from_user(&u, optval, optlen))
            return -EFAULT;

      switch(optname) {
            case DSO_CONDATA:
                  if (sock->state == SS_CONNECTED)
                        return -EISCONN;
                  if ((scp->state != DN_O) && (scp->state != DN_CR))
                        return -EINVAL;

                  if (optlen != sizeof(struct optdata_dn))
                        return -EINVAL;

                  if (dn_ntohs(u.opt.opt_optl) > 16)
                        return -EINVAL;

                  memcpy(&scp->conndata_out, &u.opt, optlen);
                  break;

            case DSO_DISDATA:
                  if (sock->state != SS_CONNECTED && scp->accept_mode == ACC_IMMED)
                        return -ENOTCONN;

                  if (optlen != sizeof(struct optdata_dn))
                        return -EINVAL;

                  if (dn_ntohs(u.opt.opt_optl) > 16)
                        return -EINVAL;

                  memcpy(&scp->discdata_out, &u.opt, optlen);
                  break;

            case DSO_CONACCESS:
                  if (sock->state == SS_CONNECTED)
                        return -EISCONN;
                  if (scp->state != DN_O)
                        return -EINVAL;

                  if (optlen != sizeof(struct accessdata_dn))
                        return -EINVAL;

                  if ((u.acc.acc_accl > DN_MAXACCL) ||
                              (u.acc.acc_passl > DN_MAXACCL) ||
                              (u.acc.acc_userl > DN_MAXACCL))
                        return -EINVAL;

                  memcpy(&scp->accessdata, &u.acc, optlen);
                  break;

            case DSO_ACCEPTMODE:
                  if (sock->state == SS_CONNECTED)
                        return -EISCONN;
                  if (scp->state != DN_O)
                        return -EINVAL;

                  if (optlen != sizeof(int))
                        return -EINVAL;

                  if ((u.mode != ACC_IMMED) && (u.mode != ACC_DEFER))
                        return -EINVAL;

                  scp->accept_mode = (unsigned char)u.mode;
                  break;

            case DSO_CONACCEPT:

                  if (scp->state != DN_CR)
                        return -EINVAL;
                  timeo = sock_rcvtimeo(sk, 0);
                  err = dn_confirm_accept(sk, &timeo, sk->sk_allocation);
                  return err;

            case DSO_CONREJECT:

                  if (scp->state != DN_CR)
                        return -EINVAL;

                  scp->state = DN_DR;
                  sk->sk_shutdown = SHUTDOWN_MASK;
                  dn_nsp_send_disc(sk, 0x38, 0, sk->sk_allocation);
                  break;

            default:
#ifdef CONFIG_NETFILTER
            return nf_setsockopt(sk, PF_DECnet, optname, optval, optlen);
#endif
            case DSO_LINKINFO:
            case DSO_STREAM:
            case DSO_SEQPACKET:
                  return -ENOPROTOOPT;

            case DSO_MAXWINDOW:
                  if (optlen != sizeof(unsigned long))
                        return -EINVAL;
                  if (u.win > NSP_MAX_WINDOW)
                        u.win = NSP_MAX_WINDOW;
                  if (u.win == 0)
                        return -EINVAL;
                  scp->max_window = u.win;
                  if (scp->snd_window > u.win)
                        scp->snd_window = u.win;
                  break;

            case DSO_NODELAY:
                  if (optlen != sizeof(int))
                        return -EINVAL;
                  if (scp->nonagle == 2)
                        return -EINVAL;
                  scp->nonagle = (u.val == 0) ? 0 : 1;
                  /* if (scp->nonagle == 1) { Push pending frames } */
                  break;

            case DSO_CORK:
                  if (optlen != sizeof(int))
                        return -EINVAL;
                  if (scp->nonagle == 1)
                        return -EINVAL;
                  scp->nonagle = (u.val == 0) ? 0 : 2;
                  /* if (scp->nonagle == 0) { Push pending frames } */
                  break;

            case DSO_SERVICES:
                  if (optlen != sizeof(unsigned char))
                        return -EINVAL;
                  if ((u.services & ~NSP_FC_MASK) != 0x01)
                        return -EINVAL;
                  if ((u.services & NSP_FC_MASK) == NSP_FC_MASK)
                        return -EINVAL;
                  scp->services_loc = u.services;
                  break;

            case DSO_INFO:
                  if (optlen != sizeof(unsigned char))
                        return -EINVAL;
                  if (u.info & 0xfc)
                        return -EINVAL;
                  scp->info_loc = u.info;
                  break;
      }

      return 0;
}

static int dn_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
{
      struct sock *sk = sock->sk;
      int err;

      lock_sock(sk);
      err = __dn_getsockopt(sock, level, optname, optval, optlen, 0);
      release_sock(sk);

      return err;
}

static int __dn_getsockopt(struct socket *sock, int level,int optname, char __user *optval,int __user *optlen, int flags)
{
      struct      sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      struct linkinfo_dn link;
      unsigned int r_len;
      void *r_data = NULL;
      unsigned int val;

      if(get_user(r_len , optlen))
            return -EFAULT;

      switch(optname) {
            case DSO_CONDATA:
                  if (r_len > sizeof(struct optdata_dn))
                        r_len = sizeof(struct optdata_dn);
                  r_data = &scp->conndata_in;
                  break;

            case DSO_DISDATA:
                  if (r_len > sizeof(struct optdata_dn))
                        r_len = sizeof(struct optdata_dn);
                  r_data = &scp->discdata_in;
                  break;

            case DSO_CONACCESS:
                  if (r_len > sizeof(struct accessdata_dn))
                        r_len = sizeof(struct accessdata_dn);
                  r_data = &scp->accessdata;
                  break;

            case DSO_ACCEPTMODE:
                  if (r_len > sizeof(unsigned char))
                        r_len = sizeof(unsigned char);
                  r_data = &scp->accept_mode;
                  break;

            case DSO_LINKINFO:
                  if (r_len > sizeof(struct linkinfo_dn))
                        r_len = sizeof(struct linkinfo_dn);

                  switch(sock->state) {
                        case SS_CONNECTING:
                              link.idn_linkstate = LL_CONNECTING;
                              break;
                        case SS_DISCONNECTING:
                              link.idn_linkstate = LL_DISCONNECTING;
                              break;
                        case SS_CONNECTED:
                              link.idn_linkstate = LL_RUNNING;
                              break;
                        default:
                              link.idn_linkstate = LL_INACTIVE;
                  }

                  link.idn_segsize = scp->segsize_rem;
                  r_data = &link;
                  break;

            default:
#ifdef CONFIG_NETFILTER
            {
                  int val, len;

                  if(get_user(len, optlen))
                        return -EFAULT;

                  val = nf_getsockopt(sk, PF_DECnet, optname,
                                          optval, &len);
                  if (val >= 0)
                        val = put_user(len, optlen);
                  return val;
            }
#endif
            case DSO_STREAM:
            case DSO_SEQPACKET:
            case DSO_CONACCEPT:
            case DSO_CONREJECT:
                  return -ENOPROTOOPT;

            case DSO_MAXWINDOW:
                  if (r_len > sizeof(unsigned long))
                        r_len = sizeof(unsigned long);
                  r_data = &scp->max_window;
                  break;

            case DSO_NODELAY:
                  if (r_len > sizeof(int))
                        r_len = sizeof(int);
                  val = (scp->nonagle == 1);
                  r_data = &val;
                  break;

            case DSO_CORK:
                  if (r_len > sizeof(int))
                        r_len = sizeof(int);
                  val = (scp->nonagle == 2);
                  r_data = &val;
                  break;

            case DSO_SERVICES:
                  if (r_len > sizeof(unsigned char))
                        r_len = sizeof(unsigned char);
                  r_data = &scp->services_rem;
                  break;

            case DSO_INFO:
                  if (r_len > sizeof(unsigned char))
                        r_len = sizeof(unsigned char);
                  r_data = &scp->info_rem;
                  break;
      }

      if (r_data) {
            if (copy_to_user(optval, r_data, r_len))
                  return -EFAULT;
            if (put_user(r_len, optlen))
                  return -EFAULT;
      }

      return 0;
}


static int dn_data_ready(struct sock *sk, struct sk_buff_head *q, int flags, int target)
{
      struct sk_buff *skb = q->next;
      int len = 0;

      if (flags & MSG_OOB)
            return !skb_queue_empty(q) ? 1 : 0;

      while(skb != (struct sk_buff *)q) {
            struct dn_skb_cb *cb = DN_SKB_CB(skb);
            len += skb->len;

            if (cb->nsp_flags & 0x40) {
                  /* SOCK_SEQPACKET reads to EOM */
                  if (sk->sk_type == SOCK_SEQPACKET)
                        return 1;
                  /* so does SOCK_STREAM unless WAITALL is specified */
                  if (!(flags & MSG_WAITALL))
                        return 1;
            }

            /* minimum data length for read exceeded */
            if (len >= target)
                  return 1;

            skb = skb->next;
      }

      return 0;
}


static int dn_recvmsg(struct kiocb *iocb, struct socket *sock,
      struct msghdr *msg, size_t size, int flags)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      struct sk_buff_head *queue = &sk->sk_receive_queue;
      size_t target = size > 1 ? 1 : 0;
      size_t copied = 0;
      int rv = 0;
      struct sk_buff *skb, *nskb;
      struct dn_skb_cb *cb = NULL;
      unsigned char eor = 0;
      long timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);

      lock_sock(sk);

      if (sock_flag(sk, SOCK_ZAPPED)) {
            rv = -EADDRNOTAVAIL;
            goto out;
      }

      if (sk->sk_shutdown & RCV_SHUTDOWN) {
            rv = 0;
            goto out;
      }

      rv = dn_check_state(sk, NULL, 0, &timeo, flags);
      if (rv)
            goto out;

      if (flags & ~(MSG_CMSG_COMPAT|MSG_PEEK|MSG_OOB|MSG_WAITALL|MSG_DONTWAIT|MSG_NOSIGNAL)) {
            rv = -EOPNOTSUPP;
            goto out;
      }

      if (flags & MSG_OOB)
            queue = &scp->other_receive_queue;

      if (flags & MSG_WAITALL)
            target = size;


      /*
       * See if there is data ready to read, sleep if there isn't
       */
      for(;;) {
            if (sk->sk_err)
                  goto out;

            if (!skb_queue_empty(&scp->other_receive_queue)) {
                  if (!(flags & MSG_OOB)) {
                        msg->msg_flags |= MSG_OOB;
                        if (!scp->other_report) {
                              scp->other_report = 1;
                              goto out;
                        }
                  }
            }

            if (scp->state != DN_RUN)
                  goto out;

            if (signal_pending(current)) {
                  rv = sock_intr_errno(timeo);
                  goto out;
            }

            if (dn_data_ready(sk, queue, flags, target))
                  break;

            if (flags & MSG_DONTWAIT) {
                  rv = -EWOULDBLOCK;
                  goto out;
            }

            set_bit(SOCK_ASYNC_WAITDATA, &sock->flags);
            SOCK_SLEEP_PRE(sk)

            if (!dn_data_ready(sk, queue, flags, target))
                  schedule();

            SOCK_SLEEP_POST(sk)
            clear_bit(SOCK_ASYNC_WAITDATA, &sock->flags);
      }

      for(skb = queue->next; skb != (struct sk_buff *)queue; skb = nskb) {
            unsigned int chunk = skb->len;
            cb = DN_SKB_CB(skb);

            if ((chunk + copied) > size)
                  chunk = size - copied;

            if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
                  rv = -EFAULT;
                  break;
            }
            copied += chunk;

            if (!(flags & MSG_PEEK))
                  skb_pull(skb, chunk);

            eor = cb->nsp_flags & 0x40;
            nskb = skb->next;

            if (skb->len == 0) {
                  skb_unlink(skb, queue);
                  kfree_skb(skb);
                  /*
                   * N.B. Don't refer to skb or cb after this point
                   * in loop.
                   */
                  if ((scp->flowloc_sw == DN_DONTSEND) && !dn_congested(sk)) {
                        scp->flowloc_sw = DN_SEND;
                        dn_nsp_send_link(sk, DN_SEND, 0);
                  }
            }

            if (eor) {
                  if (sk->sk_type == SOCK_SEQPACKET)
                        break;
                  if (!(flags & MSG_WAITALL))
                        break;
            }

            if (flags & MSG_OOB)
                  break;

            if (copied >= target)
                  break;
      }

      rv = copied;


      if (eor && (sk->sk_type == SOCK_SEQPACKET))
            msg->msg_flags |= MSG_EOR;

out:
      if (rv == 0)
            rv = (flags & MSG_PEEK) ? -sk->sk_err : sock_error(sk);

      if ((rv >= 0) && msg->msg_name) {
            memcpy(msg->msg_name, &scp->peer, sizeof(struct sockaddr_dn));
            msg->msg_namelen = sizeof(struct sockaddr_dn);
      }

      release_sock(sk);

      return rv;
}


static inline int dn_queue_too_long(struct dn_scp *scp, struct sk_buff_head *queue, int flags)
{
      unsigned char fctype = scp->services_rem & NSP_FC_MASK;
      if (skb_queue_len(queue) >= scp->snd_window)
            return 1;
      if (fctype != NSP_FC_NONE) {
            if (flags & MSG_OOB) {
                  if (scp->flowrem_oth == 0)
                        return 1;
            } else {
                  if (scp->flowrem_dat == 0)
                        return 1;
            }
      }
      return 0;
}

/*
 * The DECnet spec requires that the "routing layer" accepts packets which
 * are at least 230 bytes in size. This excludes any headers which the NSP
 * layer might add, so we always assume that we'll be using the maximal
 * length header on data packets. The variation in length is due to the
 * inclusion (or not) of the two 16 bit acknowledgement fields so it doesn't
 * make much practical difference.
 */
unsigned dn_mss_from_pmtu(struct net_device *dev, int mtu)
{
      unsigned mss = 230 - DN_MAX_NSP_DATA_HEADER;
      if (dev) {
            struct dn_dev *dn_db = dev->dn_ptr;
            mtu -= LL_RESERVED_SPACE(dev);
            if (dn_db->use_long)
                  mtu -= 21;
            else
                  mtu -= 6;
            mtu -= DN_MAX_NSP_DATA_HEADER;
      } else {
            /*
             * 21 = long header, 16 = guess at MAC header length
             */
            mtu -= (21 + DN_MAX_NSP_DATA_HEADER + 16);
      }
      if (mtu > mss)
            mss = mtu;
      return mss;
}

static inline unsigned int dn_current_mss(struct sock *sk, int flags)
{
      struct dst_entry *dst = __sk_dst_get(sk);
      struct dn_scp *scp = DN_SK(sk);
      int mss_now = min_t(int, scp->segsize_loc, scp->segsize_rem);

      /* Other data messages are limited to 16 bytes per packet */
      if (flags & MSG_OOB)
            return 16;

      /* This works out the maximum size of segment we can send out */
      if (dst) {
            u32 mtu = dst_mtu(dst);
            mss_now = min_t(int, dn_mss_from_pmtu(dst->dev, mtu), mss_now);
      }

      return mss_now;
}

/*
 * N.B. We get the timeout wrong here, but then we always did get it
 * wrong before and this is another step along the road to correcting
 * it. It ought to get updated each time we pass through the routine,
 * but in practise it probably doesn't matter too much for now.
 */
static inline struct sk_buff *dn_alloc_send_pskb(struct sock *sk,
                        unsigned long datalen, int noblock,
                        int *errcode)
{
      struct sk_buff *skb = sock_alloc_send_skb(sk, datalen,
                                       noblock, errcode);
      if (skb) {
            skb->protocol = __constant_htons(ETH_P_DNA_RT);
            skb->pkt_type = PACKET_OUTGOING;
      }
      return skb;
}

static int dn_sendmsg(struct kiocb *iocb, struct socket *sock,
                  struct msghdr *msg, size_t size)
{
      struct sock *sk = sock->sk;
      struct dn_scp *scp = DN_SK(sk);
      size_t mss;
      struct sk_buff_head *queue = &scp->data_xmit_queue;
      int flags = msg->msg_flags;
      int err = 0;
      size_t sent = 0;
      int addr_len = msg->msg_namelen;
      struct sockaddr_dn *addr = (struct sockaddr_dn *)msg->msg_name;
      struct sk_buff *skb = NULL;
      struct dn_skb_cb *cb;
      size_t len;
      unsigned char fctype;
      long timeo;

      if (flags & ~(MSG_TRYHARD|MSG_OOB|MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|MSG_MORE|MSG_CMSG_COMPAT))
            return -EOPNOTSUPP;

      if (addr_len && (addr_len != sizeof(struct sockaddr_dn)))
            return -EINVAL;

      lock_sock(sk);
      timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
      /*
       * The only difference between stream sockets and sequenced packet
       * sockets is that the stream sockets always behave as if MSG_EOR
       * has been set.
       */
      if (sock->type == SOCK_STREAM) {
            if (flags & MSG_EOR) {
                  err = -EINVAL;
                  goto out;
            }
            flags |= MSG_EOR;
      }


      err = dn_check_state(sk, addr, addr_len, &timeo, flags);
      if (err)
            goto out_err;

      if (sk->sk_shutdown & SEND_SHUTDOWN) {
            err = -EPIPE;
            if (!(flags & MSG_NOSIGNAL))
                  send_sig(SIGPIPE, current, 0);
            goto out_err;
      }

      if ((flags & MSG_TRYHARD) && sk->sk_dst_cache)
            dst_negative_advice(&sk->sk_dst_cache);

      mss = scp->segsize_rem;
      fctype = scp->services_rem & NSP_FC_MASK;

      mss = dn_current_mss(sk, flags);

      if (flags & MSG_OOB) {
            queue = &scp->other_xmit_queue;
            if (size > mss) {
                  err = -EMSGSIZE;
                  goto out;
            }
      }

      scp->persist_fxn = dn_nsp_xmit_timeout;

      while(sent < size) {
            err = sock_error(sk);
            if (err)
                  goto out;

            if (signal_pending(current)) {
                  err = sock_intr_errno(timeo);
                  goto out;
            }

            /*
             * Calculate size that we wish to send.
             */
            len = size - sent;

            if (len > mss)
                  len = mss;

            /*
             * Wait for queue size to go down below the window
             * size.
             */
            if (dn_queue_too_long(scp, queue, flags)) {
                  if (flags & MSG_DONTWAIT) {
                        err = -EWOULDBLOCK;
                        goto out;
                  }

                  SOCK_SLEEP_PRE(sk)

                  if (dn_queue_too_long(scp, queue, flags))
                        schedule();

                  SOCK_SLEEP_POST(sk)

                  continue;
            }

            /*
             * Get a suitably sized skb.
             * 64 is a bit of a hack really, but its larger than any
             * link-layer headers and has served us well as a good
             * guess as to their real length.
             */
            skb = dn_alloc_send_pskb(sk, len + 64 + DN_MAX_NSP_DATA_HEADER,
                               flags & MSG_DONTWAIT, &err);

            if (err)
                  break;

            if (!skb)
                  continue;

            cb = DN_SKB_CB(skb);

            skb_reserve(skb, 64 + DN_MAX_NSP_DATA_HEADER);

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

            if (flags & MSG_OOB) {
                  cb->nsp_flags = 0x30;
                  if (fctype != NSP_FC_NONE)
                        scp->flowrem_oth--;
            } else {
                  cb->nsp_flags = 0x00;
                  if (scp->seg_total == 0)
                        cb->nsp_flags |= 0x20;

                  scp->seg_total += len;

                  if (((sent + len) == size) && (flags & MSG_EOR)) {
                        cb->nsp_flags |= 0x40;
                        scp->seg_total = 0;
                        if (fctype == NSP_FC_SCMC)
                              scp->flowrem_dat--;
                  }
                  if (fctype == NSP_FC_SRC)
                        scp->flowrem_dat--;
            }

            sent += len;
            dn_nsp_queue_xmit(sk, skb, sk->sk_allocation, flags & MSG_OOB);
            skb = NULL;

            scp->persist = dn_nsp_persist(sk);

      }
out:

      if (skb)
            kfree_skb(skb);

      release_sock(sk);

      return sent ? sent : err;

out_err:
      err = sk_stream_error(sk, flags, err);
      release_sock(sk);
      return err;
}

static int dn_device_event(struct notifier_block *this, unsigned long event,
                  void *ptr)
{
      struct net_device *dev = (struct net_device *)ptr;

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

      switch(event) {
            case NETDEV_UP:
                  dn_dev_up(dev);
                  break;
            case NETDEV_DOWN:
                  dn_dev_down(dev);
                  break;
            default:
                  break;
      }

      return NOTIFY_DONE;
}

static struct notifier_block dn_dev_notifier = {
      .notifier_call = dn_device_event,
};

extern int dn_route_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);

static struct packet_type dn_dix_packet_type = {
      .type =           __constant_htons(ETH_P_DNA_RT),
      .dev =            NULL,       /* All devices */
      .func =           dn_route_rcv,
};

#ifdef CONFIG_PROC_FS
struct dn_iter_state {
      int bucket;
};

static struct sock *dn_socket_get_first(struct seq_file *seq)
{
      struct dn_iter_state *state = seq->private;
      struct sock *n = NULL;

      for(state->bucket = 0;
          state->bucket < DN_SK_HASH_SIZE;
          ++state->bucket) {
            n = sk_head(&dn_sk_hash[state->bucket]);
            if (n)
                  break;
      }

      return n;
}

static struct sock *dn_socket_get_next(struct seq_file *seq,
                               struct sock *n)
{
      struct dn_iter_state *state = seq->private;

      n = sk_next(n);
try_again:
      if (n)
            goto out;
      if (++state->bucket >= DN_SK_HASH_SIZE)
            goto out;
      n = sk_head(&dn_sk_hash[state->bucket]);
      goto try_again;
out:
      return n;
}

static struct sock *socket_get_idx(struct seq_file *seq, loff_t *pos)
{
      struct sock *sk = dn_socket_get_first(seq);

      if (sk) {
            while(*pos && (sk = dn_socket_get_next(seq, sk)))
                  --*pos;
      }
      return *pos ? NULL : sk;
}

static void *dn_socket_get_idx(struct seq_file *seq, loff_t pos)
{
      void *rc;
      read_lock_bh(&dn_hash_lock);
      rc = socket_get_idx(seq, &pos);
      if (!rc) {
            read_unlock_bh(&dn_hash_lock);
      }
      return rc;
}

static void *dn_socket_seq_start(struct seq_file *seq, loff_t *pos)
{
      return *pos ? dn_socket_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *dn_socket_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
      void *rc;

      if (v == SEQ_START_TOKEN) {
            rc = dn_socket_get_idx(seq, 0);
            goto out;
      }

      rc = dn_socket_get_next(seq, v);
      if (rc)
            goto out;
      read_unlock_bh(&dn_hash_lock);
out:
      ++*pos;
      return rc;
}

static void dn_socket_seq_stop(struct seq_file *seq, void *v)
{
      if (v && v != SEQ_START_TOKEN)
            read_unlock_bh(&dn_hash_lock);
}

#define IS_NOT_PRINTABLE(x) ((x) < 32 || (x) > 126)

static void dn_printable_object(struct sockaddr_dn *dn, unsigned char *buf)
{
      int i;

      switch (dn_ntohs(dn->sdn_objnamel)) {
            case 0:
                  sprintf(buf, "%d", dn->sdn_objnum);
                  break;
            default:
                  for (i = 0; i < dn_ntohs(dn->sdn_objnamel); i++) {
                        buf[i] = dn->sdn_objname[i];
                        if (IS_NOT_PRINTABLE(buf[i]))
                              buf[i] = '.';
                  }
                  buf[i] = 0;
      }
}

static char *dn_state2asc(unsigned char state)
{
      switch(state) {
            case DN_O:
                  return "OPEN";
            case DN_CR:
                  return "  CR";
            case DN_DR:
                  return "  DR";
            case DN_DRC:
                  return " DRC";
            case DN_CC:
                  return "  CC";
            case DN_CI:
                  return "  CI";
            case DN_NR:
                  return "  NR";
            case DN_NC:
                  return "  NC";
            case DN_CD:
                  return "  CD";
            case DN_RJ:
                  return "  RJ";
            case DN_RUN:
                  return " RUN";
            case DN_DI:
                  return "  DI";
            case DN_DIC:
                  return " DIC";
            case DN_DN:
                  return "  DN";
            case DN_CL:
                  return "  CL";
            case DN_CN:
                  return "  CN";
      }

      return "????";
}

static inline void dn_socket_format_entry(struct seq_file *seq, struct sock *sk)
{
      struct dn_scp *scp = DN_SK(sk);
      char buf1[DN_ASCBUF_LEN];
      char buf2[DN_ASCBUF_LEN];
      char local_object[DN_MAXOBJL+3];
      char remote_object[DN_MAXOBJL+3];

      dn_printable_object(&scp->addr, local_object);
      dn_printable_object(&scp->peer, remote_object);

      seq_printf(seq,
               "%6s/%04X %04d:%04d %04d:%04d %01d %-16s "
               "%6s/%04X %04d:%04d %04d:%04d %01d %-16s %4s %s\n",
               dn_addr2asc(dn_ntohs(dn_saddr2dn(&scp->addr)), buf1),
               scp->addrloc,
               scp->numdat,
               scp->numoth,
               scp->ackxmt_dat,
               scp->ackxmt_oth,
               scp->flowloc_sw,
               local_object,
               dn_addr2asc(dn_ntohs(dn_saddr2dn(&scp->peer)), buf2),
               scp->addrrem,
               scp->numdat_rcv,
               scp->numoth_rcv,
               scp->ackrcv_dat,
               scp->ackrcv_oth,
               scp->flowrem_sw,
               remote_object,
               dn_state2asc(scp->state),
               ((scp->accept_mode == ACC_IMMED) ? "IMMED" : "DEFER"));
}

static int dn_socket_seq_show(struct seq_file *seq, void *v)
{
      if (v == SEQ_START_TOKEN) {
            seq_puts(seq, "Local                                              Remote\n");
      } else {
            dn_socket_format_entry(seq, v);
      }
      return 0;
}

static const struct seq_operations dn_socket_seq_ops = {
      .start      = dn_socket_seq_start,
      .next = dn_socket_seq_next,
      .stop = dn_socket_seq_stop,
      .show = dn_socket_seq_show,
};

static int dn_socket_seq_open(struct inode *inode, struct file *file)
{
      struct seq_file *seq;
      int rc = -ENOMEM;
      struct dn_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);

      if (!s)
            goto out;

      rc = seq_open(file, &dn_socket_seq_ops);
      if (rc)
            goto out_kfree;

      seq         = file->private_data;
      seq->private      = s;
      memset(s, 0, sizeof(*s));
out:
      return rc;
out_kfree:
      kfree(s);
      goto out;
}

static const struct file_operations dn_socket_seq_fops = {
      .owner            = THIS_MODULE,
      .open       = dn_socket_seq_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release_private,
};
#endif

static struct net_proto_family      dn_family_ops = {
      .family =   AF_DECnet,
      .create =   dn_create,
      .owner      =     THIS_MODULE,
};

static const struct proto_ops dn_proto_ops = {
      .family =   AF_DECnet,
      .owner =    THIS_MODULE,
      .release =  dn_release,
      .bind =           dn_bind,
      .connect =  dn_connect,
      .socketpair =     sock_no_socketpair,
      .accept =   dn_accept,
      .getname =  dn_getname,
      .poll =           dn_poll,
      .ioctl =    dn_ioctl,
      .listen =   dn_listen,
      .shutdown = dn_shutdown,
      .setsockopt =     dn_setsockopt,
      .getsockopt =     dn_getsockopt,
      .sendmsg =  dn_sendmsg,
      .recvmsg =  dn_recvmsg,
      .mmap =           sock_no_mmap,
      .sendpage = sock_no_sendpage,
};

void dn_register_sysctl(void);
void dn_unregister_sysctl(void);

MODULE_DESCRIPTION("The Linux DECnet Network Protocol");
MODULE_AUTHOR("Linux DECnet Project Team");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_DECnet);

static char banner[] __initdata = KERN_INFO "NET4: DECnet for Linux: V.2.5.68s (C) 1995-2003 Linux DECnet Project Team\n";

static int __init decnet_init(void)
{
      int rc;

      printk(banner);

      rc = proto_register(&dn_proto, 1);
      if (rc != 0)
            goto out;

      dn_neigh_init();
      dn_dev_init();
      dn_route_init();
      dn_fib_init();

      sock_register(&dn_family_ops);
      dev_add_pack(&dn_dix_packet_type);
      register_netdevice_notifier(&dn_dev_notifier);

      proc_net_fops_create(&init_net, "decnet", S_IRUGO, &dn_socket_seq_fops);
      dn_register_sysctl();
out:
      return rc;

}
module_init(decnet_init);

/*
 * Prevent DECnet module unloading until its fixed properly.
 * Requires an audit of the code to check for memory leaks and
 * initialisation problems etc.
 */
#if 0
static void __exit decnet_exit(void)
{
      sock_unregister(AF_DECnet);
      rtnl_unregister_all(PF_DECnet);
      dev_remove_pack(&dn_dix_packet_type);

      dn_unregister_sysctl();

      unregister_netdevice_notifier(&dn_dev_notifier);

      dn_route_cleanup();
      dn_dev_cleanup();
      dn_neigh_cleanup();
      dn_fib_cleanup();

      proc_net_remove(&init_net, "decnet");

      proto_unregister(&dn_proto);
}
module_exit(decnet_exit);
#endif

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