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sock.c

/*
 * INET           An implementation of the TCP/IP protocol suite for the LINUX
 *          operating system.  INET is implemented using the  BSD Socket
 *          interface as the means of communication with the user level.
 *
 *          Generic socket support routines. Memory allocators, socket lock/release
 *          handler for protocols to use and generic option handler.
 *
 *
 * Version: $Id: sock.c,v 1.117 2002/02/01 22:01:03 davem Exp $
 *
 * Authors: Ross Biro
 *          Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *          Florian La Roche, <flla@stud.uni-sb.de>
 *          Alan Cox, <A.Cox@swansea.ac.uk>
 *
 * Fixes:
 *          Alan Cox    :     Numerous verify_area() problems
 *          Alan Cox    :     Connecting on a connecting socket
 *                            now returns an error for tcp.
 *          Alan Cox    :     sock->protocol is set correctly.
 *                            and is not sometimes left as 0.
 *          Alan Cox    :     connect handles icmp errors on a
 *                            connect properly. Unfortunately there
 *                            is a restart syscall nasty there. I
 *                            can't match BSD without hacking the C
 *                            library. Ideas urgently sought!
 *          Alan Cox    :     Disallow bind() to addresses that are
 *                            not ours - especially broadcast ones!!
 *          Alan Cox    :     Socket 1024 _IS_ ok for users. (fencepost)
 *          Alan Cox    :     sock_wfree/sock_rfree don't destroy sockets,
 *                            instead they leave that for the DESTROY timer.
 *          Alan Cox    :     Clean up error flag in accept
 *          Alan Cox    :     TCP ack handling is buggy, the DESTROY timer
 *                            was buggy. Put a remove_sock() in the handler
 *                            for memory when we hit 0. Also altered the timer
 *                            code. The ACK stuff can wait and needs major 
 *                            TCP layer surgery.
 *          Alan Cox    :     Fixed TCP ack bug, removed remove sock
 *                            and fixed timer/inet_bh race.
 *          Alan Cox    :     Added zapped flag for TCP
 *          Alan Cox    :     Move kfree_skb into skbuff.c and tidied up surplus code
 *          Alan Cox    :     for new sk_buff allocations wmalloc/rmalloc now call alloc_skb
 *          Alan Cox    :     kfree_s calls now are kfree_skbmem so we can track skb resources
 *          Alan Cox    :     Supports socket option broadcast now as does udp. Packet and raw need fixing.
 *          Alan Cox    :     Added RCVBUF,SNDBUF size setting. It suddenly occurred to me how easy it was so...
 *          Rick Sladkey      :     Relaxed UDP rules for matching packets.
 *          C.E.Hawkins :     IFF_PROMISC/SIOCGHWADDR support
 *    Pauline Middelink :     identd support
 *          Alan Cox    :     Fixed connect() taking signals I think.
 *          Alan Cox    :     SO_LINGER supported
 *          Alan Cox    :     Error reporting fixes
 *          Anonymous   :     inet_create tidied up (sk->reuse setting)
 *          Alan Cox    :     inet sockets don't set sk->type!
 *          Alan Cox    :     Split socket option code
 *          Alan Cox    :     Callbacks
 *          Alan Cox    :     Nagle flag for Charles & Johannes stuff
 *          Alex        :     Removed restriction on inet fioctl
 *          Alan Cox    :     Splitting INET from NET core
 *          Alan Cox    :     Fixed bogus SO_TYPE handling in getsockopt()
 *          Adam Caldwell     :     Missing return in SO_DONTROUTE/SO_DEBUG code
 *          Alan Cox    :     Split IP from generic code
 *          Alan Cox    :     New kfree_skbmem()
 *          Alan Cox    :     Make SO_DEBUG superuser only.
 *          Alan Cox    :     Allow anyone to clear SO_DEBUG
 *                            (compatibility fix)
 *          Alan Cox    :     Added optimistic memory grabbing for AF_UNIX throughput.
 *          Alan Cox    :     Allocator for a socket is settable.
 *          Alan Cox    :     SO_ERROR includes soft errors.
 *          Alan Cox    :     Allow NULL arguments on some SO_ opts
 *          Alan Cox    :     Generic socket allocation to make hooks
 *                            easier (suggested by Craig Metz).
 *          Michael Pall      :     SO_ERROR returns positive errno again
 *              Steve Whitehouse:       Added default destructor to free
 *                                      protocol private data.
 *              Steve Whitehouse:       Added various other default routines
 *                                      common to several socket families.
 *              Chris Evans     :       Call suser() check last on F_SETOWN
 *          Jay Schulist      :     Added SO_ATTACH_FILTER and SO_DETACH_FILTER.
 *          Andi Kleen  :     Add sock_kmalloc()/sock_kfree_s()
 *          Andi Kleen  :     Fix write_space callback
 *          Chris Evans :     Security fixes - signedness again
 *          Arnaldo C. Melo :       cleanups, use skb_queue_purge
 *
 * To Fix:
 *
 *
 *          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/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/tcp.h>
#include <linux/init.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#include <linux/netdevice.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/request_sock.h>
#include <net/sock.h>
#include <net/xfrm.h>
#include <linux/ipsec.h>

#include <linux/filter.h>

#ifdef CONFIG_INET
#include <net/tcp.h>
#endif

/*
 * Each address family might have different locking rules, so we have
 * one slock key per address family:
 */
static struct lock_class_key af_family_keys[AF_MAX];
static struct lock_class_key af_family_slock_keys[AF_MAX];

#ifdef CONFIG_DEBUG_LOCK_ALLOC
/*
 * Make lock validator output more readable. (we pre-construct these
 * strings build-time, so that runtime initialization of socket
 * locks is fast):
 */
static const char *af_family_key_strings[AF_MAX+1] = {
  "sk_lock-AF_UNSPEC", "sk_lock-AF_UNIX"     , "sk_lock-AF_INET"     ,
  "sk_lock-AF_AX25"  , "sk_lock-AF_IPX"      , "sk_lock-AF_APPLETALK",
  "sk_lock-AF_NETROM", "sk_lock-AF_BRIDGE"   , "sk_lock-AF_ATMPVC"   ,
  "sk_lock-AF_X25"   , "sk_lock-AF_INET6"    , "sk_lock-AF_ROSE"     ,
  "sk_lock-AF_DECnet", "sk_lock-AF_NETBEUI"  , "sk_lock-AF_SECURITY" ,
  "sk_lock-AF_KEY"   , "sk_lock-AF_NETLINK"  , "sk_lock-AF_PACKET"   ,
  "sk_lock-AF_ASH"   , "sk_lock-AF_ECONET"   , "sk_lock-AF_ATMSVC"   ,
  "sk_lock-21"       , "sk_lock-AF_SNA"      , "sk_lock-AF_IRDA"     ,
  "sk_lock-AF_PPPOX" , "sk_lock-AF_WANPIPE"  , "sk_lock-AF_LLC"      ,
  "sk_lock-27"       , "sk_lock-28"          , "sk_lock-29"          ,
  "sk_lock-AF_TIPC"  , "sk_lock-AF_BLUETOOTH", "sk_lock-AF_MAX"
};
static const char *af_family_slock_key_strings[AF_MAX+1] = {
  "slock-AF_UNSPEC", "slock-AF_UNIX"     , "slock-AF_INET"     ,
  "slock-AF_AX25"  , "slock-AF_IPX"      , "slock-AF_APPLETALK",
  "slock-AF_NETROM", "slock-AF_BRIDGE"   , "slock-AF_ATMPVC"   ,
  "slock-AF_X25"   , "slock-AF_INET6"    , "slock-AF_ROSE"     ,
  "slock-AF_DECnet", "slock-AF_NETBEUI"  , "slock-AF_SECURITY" ,
  "slock-AF_KEY"   , "slock-AF_NETLINK"  , "slock-AF_PACKET"   ,
  "slock-AF_ASH"   , "slock-AF_ECONET"   , "slock-AF_ATMSVC"   ,
  "slock-21"       , "slock-AF_SNA"      , "slock-AF_IRDA"     ,
  "slock-AF_PPPOX" , "slock-AF_WANPIPE"  , "slock-AF_LLC"      ,
  "slock-27"       , "slock-28"          , "slock-29"          ,
  "slock-AF_TIPC"  , "slock-AF_BLUETOOTH", "slock-AF_MAX"
};
#endif

/*
 * sk_callback_lock locking rules are per-address-family,
 * so split the lock classes by using a per-AF key:
 */
static struct lock_class_key af_callback_keys[AF_MAX];

/* Take into consideration the size of the struct sk_buff overhead in the
 * determination of these values, since that is non-constant across
 * platforms.  This makes socket queueing behavior and performance
 * not depend upon such differences.
 */
#define _SK_MEM_PACKETS       256
#define _SK_MEM_OVERHEAD      (sizeof(struct sk_buff) + 256)
#define SK_WMEM_MAX           (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
#define SK_RMEM_MAX           (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)

/* Run time adjustable parameters. */
__u32 sysctl_wmem_max = SK_WMEM_MAX;
__u32 sysctl_rmem_max = SK_RMEM_MAX;
__u32 sysctl_wmem_default = SK_WMEM_MAX;
__u32 sysctl_rmem_default = SK_RMEM_MAX;

/* Maximal space eaten by iovec or ancilliary data plus some space */
int sysctl_optmem_max = sizeof(unsigned long)*(2*UIO_MAXIOV + 512);

static int sock_set_timeout(long *timeo_p, char __user *optval, int optlen)
{
      struct timeval tv;

      if (optlen < sizeof(tv))
            return -EINVAL;
      if (copy_from_user(&tv, optval, sizeof(tv)))
            return -EFAULT;

      *timeo_p = MAX_SCHEDULE_TIMEOUT;
      if (tv.tv_sec == 0 && tv.tv_usec == 0)
            return 0;
      if (tv.tv_sec < (MAX_SCHEDULE_TIMEOUT/HZ - 1))
            *timeo_p = tv.tv_sec*HZ + (tv.tv_usec+(1000000/HZ-1))/(1000000/HZ);
      return 0;
}

static void sock_warn_obsolete_bsdism(const char *name)
{
      static int warned;
      static char warncomm[TASK_COMM_LEN];
      if (strcmp(warncomm, current->comm) && warned < 5) { 
            strcpy(warncomm,  current->comm); 
            printk(KERN_WARNING "process `%s' is using obsolete "
                   "%s SO_BSDCOMPAT\n", warncomm, name);
            warned++;
      }
}

static void sock_disable_timestamp(struct sock *sk)
{     
      if (sock_flag(sk, SOCK_TIMESTAMP)) { 
            sock_reset_flag(sk, SOCK_TIMESTAMP);
            net_disable_timestamp();
      }
}


int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
      int err = 0;
      int skb_len;

      /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
         number of warnings when compiling with -W --ANK
       */
      if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
          (unsigned)sk->sk_rcvbuf) {
            err = -ENOMEM;
            goto out;
      }

      /* It would be deadlock, if sock_queue_rcv_skb is used
         with socket lock! We assume that users of this
         function are lock free.
      */
      err = sk_filter(sk, skb, 1);
      if (err)
            goto out;

      skb->dev = NULL;
      skb_set_owner_r(skb, sk);

      /* Cache the SKB length before we tack it onto the receive
       * queue.  Once it is added it no longer belongs to us and
       * may be freed by other threads of control pulling packets
       * from the queue.
       */
      skb_len = skb->len;

      skb_queue_tail(&sk->sk_receive_queue, skb);

      if (!sock_flag(sk, SOCK_DEAD))
            sk->sk_data_ready(sk, skb_len);
out:
      return err;
}
EXPORT_SYMBOL(sock_queue_rcv_skb);

int sk_receive_skb(struct sock *sk, struct sk_buff *skb)
{
      int rc = NET_RX_SUCCESS;

      if (sk_filter(sk, skb, 0))
            goto discard_and_relse;

      skb->dev = NULL;

      bh_lock_sock(sk);
      if (!sock_owned_by_user(sk)) {
            /*
             * trylock + unlock semantics:
             */
            mutex_acquire(&sk->sk_lock.dep_map, 0, 1, _RET_IP_);

            rc = sk->sk_backlog_rcv(sk, skb);

            mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
      } else
            sk_add_backlog(sk, skb);
      bh_unlock_sock(sk);
out:
      sock_put(sk);
      return rc;
discard_and_relse:
      kfree_skb(skb);
      goto out;
}
EXPORT_SYMBOL(sk_receive_skb);

struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie)
{
      struct dst_entry *dst = sk->sk_dst_cache;

      if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
            sk->sk_dst_cache = NULL;
            dst_release(dst);
            return NULL;
      }

      return dst;
}
EXPORT_SYMBOL(__sk_dst_check);

struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie)
{
      struct dst_entry *dst = sk_dst_get(sk);

      if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
            sk_dst_reset(sk);
            dst_release(dst);
            return NULL;
      }

      return dst;
}
EXPORT_SYMBOL(sk_dst_check);

/*
 *    This is meant for all protocols to use and covers goings on
 *    at the socket level. Everything here is generic.
 */

int sock_setsockopt(struct socket *sock, int level, int optname,
                char __user *optval, int optlen)
{
      struct sock *sk=sock->sk;
      struct sk_filter *filter;
      int val;
      int valbool;
      struct linger ling;
      int ret = 0;
      
      /*
       *    Options without arguments
       */

#ifdef SO_DONTLINGER          /* Compatibility item... */
      if (optname == SO_DONTLINGER) {
            lock_sock(sk);
            sock_reset_flag(sk, SOCK_LINGER);
            release_sock(sk);
            return 0;
      }
#endif
      
      if(optlen<sizeof(int))
            return(-EINVAL);
      
      if (get_user(val, (int __user *)optval))
            return -EFAULT;
      
      valbool = val?1:0;

      lock_sock(sk);

      switch(optname) 
      {
            case SO_DEBUG:    
                  if(val && !capable(CAP_NET_ADMIN))
                  {
                        ret = -EACCES;
                  }
                  else if (valbool)
                        sock_set_flag(sk, SOCK_DBG);
                  else
                        sock_reset_flag(sk, SOCK_DBG);
                  break;
            case SO_REUSEADDR:
                  sk->sk_reuse = valbool;
                  break;
            case SO_TYPE:
            case SO_ERROR:
                  ret = -ENOPROTOOPT;
                  break;
            case SO_DONTROUTE:
                  if (valbool)
                        sock_set_flag(sk, SOCK_LOCALROUTE);
                  else
                        sock_reset_flag(sk, SOCK_LOCALROUTE);
                  break;
            case SO_BROADCAST:
                  sock_valbool_flag(sk, SOCK_BROADCAST, valbool);
                  break;
            case SO_SNDBUF:
                  /* Don't error on this BSD doesn't and if you think
                     about it this is right. Otherwise apps have to
                     play 'guess the biggest size' games. RCVBUF/SNDBUF
                     are treated in BSD as hints */
                     
                  if (val > sysctl_wmem_max)
                        val = sysctl_wmem_max;
set_sndbuf:
                  sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
                  if ((val * 2) < SOCK_MIN_SNDBUF)
                        sk->sk_sndbuf = SOCK_MIN_SNDBUF;
                  else
                        sk->sk_sndbuf = val * 2;

                  /*
                   *    Wake up sending tasks if we
                   *    upped the value.
                   */
                  sk->sk_write_space(sk);
                  break;

            case SO_SNDBUFFORCE:
                  if (!capable(CAP_NET_ADMIN)) {
                        ret = -EPERM;
                        break;
                  }
                  goto set_sndbuf;

            case SO_RCVBUF:
                  /* Don't error on this BSD doesn't and if you think
                     about it this is right. Otherwise apps have to
                     play 'guess the biggest size' games. RCVBUF/SNDBUF
                     are treated in BSD as hints */
                    
                  if (val > sysctl_rmem_max)
                        val = sysctl_rmem_max;
set_rcvbuf:
                  sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
                  /*
                   * We double it on the way in to account for
                   * "struct sk_buff" etc. overhead.   Applications
                   * assume that the SO_RCVBUF setting they make will
                   * allow that much actual data to be received on that
                   * socket.
                   *
                   * Applications are unaware that "struct sk_buff" and
                   * other overheads allocate from the receive buffer
                   * during socket buffer allocation.
                   *
                   * And after considering the possible alternatives,
                   * returning the value we actually used in getsockopt
                   * is the most desirable behavior.
                   */
                  if ((val * 2) < SOCK_MIN_RCVBUF)
                        sk->sk_rcvbuf = SOCK_MIN_RCVBUF;
                  else
                        sk->sk_rcvbuf = val * 2;
                  break;

            case SO_RCVBUFFORCE:
                  if (!capable(CAP_NET_ADMIN)) {
                        ret = -EPERM;
                        break;
                  }
                  goto set_rcvbuf;

            case SO_KEEPALIVE:
#ifdef CONFIG_INET
                  if (sk->sk_protocol == IPPROTO_TCP)
                        tcp_set_keepalive(sk, valbool);
#endif
                  sock_valbool_flag(sk, SOCK_KEEPOPEN, valbool);
                  break;

            case SO_OOBINLINE:
                  sock_valbool_flag(sk, SOCK_URGINLINE, valbool);
                  break;

            case SO_NO_CHECK:
                  sk->sk_no_check = valbool;
                  break;

            case SO_PRIORITY:
                  if ((val >= 0 && val <= 6) || capable(CAP_NET_ADMIN)) 
                        sk->sk_priority = val;
                  else
                        ret = -EPERM;
                  break;

            case SO_LINGER:
                  if(optlen<sizeof(ling)) {
                        ret = -EINVAL;    /* 1003.1g */
                        break;
                  }
                  if (copy_from_user(&ling,optval,sizeof(ling))) {
                        ret = -EFAULT;
                        break;
                  }
                  if (!ling.l_onoff)
                        sock_reset_flag(sk, SOCK_LINGER);
                  else {
#if (BITS_PER_LONG == 32)
                        if ((unsigned int)ling.l_linger >= MAX_SCHEDULE_TIMEOUT/HZ)
                              sk->sk_lingertime = MAX_SCHEDULE_TIMEOUT;
                        else
#endif
                              sk->sk_lingertime = (unsigned int)ling.l_linger * HZ;
                        sock_set_flag(sk, SOCK_LINGER);
                  }
                  break;

            case SO_BSDCOMPAT:
                  sock_warn_obsolete_bsdism("setsockopt");
                  break;

            case SO_PASSCRED:
                  if (valbool)
                        set_bit(SOCK_PASSCRED, &sock->flags);
                  else
                        clear_bit(SOCK_PASSCRED, &sock->flags);
                  break;

            case SO_TIMESTAMP:
                  if (valbool)  {
                        sock_set_flag(sk, SOCK_RCVTSTAMP);
                        sock_enable_timestamp(sk);
                  } else
                        sock_reset_flag(sk, SOCK_RCVTSTAMP);
                  break;

            case SO_RCVLOWAT:
                  if (val < 0)
                        val = INT_MAX;
                  sk->sk_rcvlowat = val ? : 1;
                  break;

            case SO_RCVTIMEO:
                  ret = sock_set_timeout(&sk->sk_rcvtimeo, optval, optlen);
                  break;

            case SO_SNDTIMEO:
                  ret = sock_set_timeout(&sk->sk_sndtimeo, optval, optlen);
                  break;

#ifdef CONFIG_NETDEVICES
            case SO_BINDTODEVICE:
            {
                  char devname[IFNAMSIZ]; 

                  /* Sorry... */ 
                  if (!capable(CAP_NET_RAW)) {
                        ret = -EPERM;
                        break;
                  }

                  /* Bind this socket to a particular device like "eth0",
                   * as specified in the passed interface name. If the
                   * name is "" or the option length is zero the socket 
                   * is not bound. 
                   */ 

                  if (!valbool) {
                        sk->sk_bound_dev_if = 0;
                  } else {
                        if (optlen > IFNAMSIZ - 1)
                              optlen = IFNAMSIZ - 1;
                        memset(devname, 0, sizeof(devname));
                        if (copy_from_user(devname, optval, optlen)) {
                              ret = -EFAULT;
                              break;
                        }

                        /* Remove any cached route for this socket. */
                        sk_dst_reset(sk);

                        if (devname[0] == '\0') {
                              sk->sk_bound_dev_if = 0;
                        } else {
                              struct net_device *dev = dev_get_by_name(devname);
                              if (!dev) {
                                    ret = -ENODEV;
                                    break;
                              }
                              sk->sk_bound_dev_if = dev->ifindex;
                              dev_put(dev);
                        }
                  }
                  break;
            }
#endif


            case SO_ATTACH_FILTER:
                  ret = -EINVAL;
                  if (optlen == sizeof(struct sock_fprog)) {
                        struct sock_fprog fprog;

                        ret = -EFAULT;
                        if (copy_from_user(&fprog, optval, sizeof(fprog)))
                              break;

                        ret = sk_attach_filter(&fprog, sk);
                  }
                  break;

            case SO_DETACH_FILTER:
                  spin_lock_bh(&sk->sk_lock.slock);
                  filter = sk->sk_filter;
                        if (filter) {
                        sk->sk_filter = NULL;
                        spin_unlock_bh(&sk->sk_lock.slock);
                        sk_filter_release(sk, filter);
                        break;
                  }
                  spin_unlock_bh(&sk->sk_lock.slock);
                  ret = -ENONET;
                  break;

            case SO_PASSSEC:
                  if (valbool)
                        set_bit(SOCK_PASSSEC, &sock->flags);
                  else
                        clear_bit(SOCK_PASSSEC, &sock->flags);
                  break;

            /* We implement the SO_SNDLOWAT etc to
               not be settable (1003.1g 5.3) */
            default:
                  ret = -ENOPROTOOPT;
                  break;
      }
      release_sock(sk);
      return ret;
}


int sock_getsockopt(struct socket *sock, int level, int optname,
                char __user *optval, int __user *optlen)
{
      struct sock *sk = sock->sk;
      
      union
      {
            int val;
            struct linger ling;
            struct timeval tm;
      } v;
      
      unsigned int lv = sizeof(int);
      int len;
      
      if(get_user(len,optlen))
            return -EFAULT;
      if(len < 0)
            return -EINVAL;
            
      switch(optname) 
      {
            case SO_DEBUG:          
                  v.val = sock_flag(sk, SOCK_DBG);
                  break;
            
            case SO_DONTROUTE:
                  v.val = sock_flag(sk, SOCK_LOCALROUTE);
                  break;
            
            case SO_BROADCAST:
                  v.val = !!sock_flag(sk, SOCK_BROADCAST);
                  break;

            case SO_SNDBUF:
                  v.val = sk->sk_sndbuf;
                  break;
            
            case SO_RCVBUF:
                  v.val = sk->sk_rcvbuf;
                  break;

            case SO_REUSEADDR:
                  v.val = sk->sk_reuse;
                  break;

            case SO_KEEPALIVE:
                  v.val = !!sock_flag(sk, SOCK_KEEPOPEN);
                  break;

            case SO_TYPE:
                  v.val = sk->sk_type;                      
                  break;

            case SO_ERROR:
                  v.val = -sock_error(sk);
                  if(v.val==0)
                        v.val = xchg(&sk->sk_err_soft, 0);
                  break;

            case SO_OOBINLINE:
                  v.val = !!sock_flag(sk, SOCK_URGINLINE);
                  break;
      
            case SO_NO_CHECK:
                  v.val = sk->sk_no_check;
                  break;

            case SO_PRIORITY:
                  v.val = sk->sk_priority;
                  break;
            
            case SO_LINGER:   
                  lv          = sizeof(v.ling);
                  v.ling.l_onoff    = !!sock_flag(sk, SOCK_LINGER);
                  v.ling.l_linger   = sk->sk_lingertime / HZ;
                  break;
                              
            case SO_BSDCOMPAT:
                  sock_warn_obsolete_bsdism("getsockopt");
                  break;

            case SO_TIMESTAMP:
                  v.val = sock_flag(sk, SOCK_RCVTSTAMP);
                  break;

            case SO_RCVTIMEO:
                  lv=sizeof(struct timeval);
                  if (sk->sk_rcvtimeo == MAX_SCHEDULE_TIMEOUT) {
                        v.tm.tv_sec = 0;
                        v.tm.tv_usec = 0;
                  } else {
                        v.tm.tv_sec = sk->sk_rcvtimeo / HZ;
                        v.tm.tv_usec = ((sk->sk_rcvtimeo % HZ) * 1000000) / HZ;
                  }
                  break;

            case SO_SNDTIMEO:
                  lv=sizeof(struct timeval);
                  if (sk->sk_sndtimeo == MAX_SCHEDULE_TIMEOUT) {
                        v.tm.tv_sec = 0;
                        v.tm.tv_usec = 0;
                  } else {
                        v.tm.tv_sec = sk->sk_sndtimeo / HZ;
                        v.tm.tv_usec = ((sk->sk_sndtimeo % HZ) * 1000000) / HZ;
                  }
                  break;

            case SO_RCVLOWAT:
                  v.val = sk->sk_rcvlowat;
                  break;

            case SO_SNDLOWAT:
                  v.val=1;
                  break; 

            case SO_PASSCRED:
                  v.val = test_bit(SOCK_PASSCRED, &sock->flags) ? 1 : 0;
                  break;

            case SO_PEERCRED:
                  if (len > sizeof(sk->sk_peercred))
                        len = sizeof(sk->sk_peercred);
                  if (copy_to_user(optval, &sk->sk_peercred, len))
                        return -EFAULT;
                  goto lenout;

            case SO_PEERNAME:
            {
                  char address[128];

                  if (sock->ops->getname(sock, (struct sockaddr *)address, &lv, 2))
                        return -ENOTCONN;
                  if (lv < len)
                        return -EINVAL;
                  if (copy_to_user(optval, address, len))
                        return -EFAULT;
                  goto lenout;
            }

            /* Dubious BSD thing... Probably nobody even uses it, but
             * the UNIX standard wants it for whatever reason... -DaveM
             */
            case SO_ACCEPTCONN:
                  v.val = sk->sk_state == TCP_LISTEN;
                  break;

            case SO_PASSSEC:
                  v.val = test_bit(SOCK_PASSSEC, &sock->flags) ? 1 : 0;
                  break;

            case SO_PEERSEC:
                  return security_socket_getpeersec_stream(sock, optval, optlen, len);

            default:
                  return(-ENOPROTOOPT);
      }
      if (len > lv)
            len = lv;
      if (copy_to_user(optval, &v, len))
            return -EFAULT;
lenout:
      if (put_user(len, optlen))
            return -EFAULT;
      return 0;
}

/*
 * Initialize an sk_lock.
 *
 * (We also register the sk_lock with the lock validator.)
 */
static void inline sock_lock_init(struct sock *sk)
{
      spin_lock_init(&sk->sk_lock.slock);
      sk->sk_lock.owner = NULL;
      init_waitqueue_head(&sk->sk_lock.wq);
      /*
       * Make sure we are not reinitializing a held lock:
       */
      debug_check_no_locks_freed((void *)&sk->sk_lock, sizeof(sk->sk_lock));

      /*
       * Mark both the sk_lock and the sk_lock.slock as a
       * per-address-family lock class:
       */
      lockdep_set_class_and_name(&sk->sk_lock.slock,
                           af_family_slock_keys + sk->sk_family,
                           af_family_slock_key_strings[sk->sk_family]);
      lockdep_init_map(&sk->sk_lock.dep_map,
                   af_family_key_strings[sk->sk_family],
                   af_family_keys + sk->sk_family);
}

/**
 *    sk_alloc - All socket objects are allocated here
 *    @family: protocol family
 *    @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 *    @prot: struct proto associated with this new sock instance
 *    @zero_it: if we should zero the newly allocated sock
 */
struct sock *sk_alloc(int family, gfp_t priority,
                  struct proto *prot, int zero_it)
{
      struct sock *sk = NULL;
      kmem_cache_t *slab = prot->slab;

      if (slab != NULL)
            sk = kmem_cache_alloc(slab, priority);
      else
            sk = kmalloc(prot->obj_size, priority);

      if (sk) {
            if (zero_it) {
                  memset(sk, 0, prot->obj_size);
                  sk->sk_family = family;
                  /*
                   * See comment in struct sock definition to understand
                   * why we need sk_prot_creator -acme
                   */
                  sk->sk_prot = sk->sk_prot_creator = prot;
                  sock_lock_init(sk);
            }
            
            if (security_sk_alloc(sk, family, priority))
                  goto out_free;

            if (!try_module_get(prot->owner))
                  goto out_free;
      }
      return sk;

out_free:
      if (slab != NULL)
            kmem_cache_free(slab, sk);
      else
            kfree(sk);
      return NULL;
}

void sk_free(struct sock *sk)
{
      struct sk_filter *filter;
      struct module *owner = sk->sk_prot_creator->owner;

      if (sk->sk_destruct)
            sk->sk_destruct(sk);

      filter = sk->sk_filter;
      if (filter) {
            sk_filter_release(sk, filter);
            sk->sk_filter = NULL;
      }

      sock_disable_timestamp(sk);

      if (atomic_read(&sk->sk_omem_alloc))
            printk(KERN_DEBUG "%s: optmem leakage (%d bytes) detected.\n",
                   __FUNCTION__, atomic_read(&sk->sk_omem_alloc));

      security_sk_free(sk);
      if (sk->sk_prot_creator->slab != NULL)
            kmem_cache_free(sk->sk_prot_creator->slab, sk);
      else
            kfree(sk);
      module_put(owner);
}

struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
{
      struct sock *newsk = sk_alloc(sk->sk_family, priority, sk->sk_prot, 0);

      if (newsk != NULL) {
            struct sk_filter *filter;

            memcpy(newsk, sk, sk->sk_prot->obj_size);

            /* SANITY */
            sk_node_init(&newsk->sk_node);
            sock_lock_init(newsk);
            bh_lock_sock(newsk);

            atomic_set(&newsk->sk_rmem_alloc, 0);
            atomic_set(&newsk->sk_wmem_alloc, 0);
            atomic_set(&newsk->sk_omem_alloc, 0);
            skb_queue_head_init(&newsk->sk_receive_queue);
            skb_queue_head_init(&newsk->sk_write_queue);
#ifdef CONFIG_NET_DMA
            skb_queue_head_init(&newsk->sk_async_wait_queue);
#endif

            rwlock_init(&newsk->sk_dst_lock);
            rwlock_init(&newsk->sk_callback_lock);
            lockdep_set_class(&newsk->sk_callback_lock,
                           af_callback_keys + newsk->sk_family);

            newsk->sk_dst_cache     = NULL;
            newsk->sk_wmem_queued   = 0;
            newsk->sk_forward_alloc = 0;
            newsk->sk_send_head     = NULL;
            newsk->sk_backlog.head  = newsk->sk_backlog.tail = NULL;
            newsk->sk_userlocks     = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;

            sock_reset_flag(newsk, SOCK_DONE);
            skb_queue_head_init(&newsk->sk_error_queue);

            filter = newsk->sk_filter;
            if (filter != NULL)
                  sk_filter_charge(newsk, filter);

            if (unlikely(xfrm_sk_clone_policy(newsk))) {
                  /* It is still raw copy of parent, so invalidate
                   * destructor and make plain sk_free() */
                  newsk->sk_destruct = NULL;
                  sk_free(newsk);
                  newsk = NULL;
                  goto out;
            }

            newsk->sk_err        = 0;
            newsk->sk_priority = 0;
            atomic_set(&newsk->sk_refcnt, 2);

            /*
             * Increment the counter in the same struct proto as the master
             * sock (sk_refcnt_debug_inc uses newsk->sk_prot->socks, that
             * is the same as sk->sk_prot->socks, as this field was copied
             * with memcpy).
             *
             * This _changes_ the previous behaviour, where
             * tcp_create_openreq_child always was incrementing the
             * equivalent to tcp_prot->socks (inet_sock_nr), so this have
             * to be taken into account in all callers. -acme
             */
            sk_refcnt_debug_inc(newsk);
            newsk->sk_socket = NULL;
            newsk->sk_sleep    = NULL;

            if (newsk->sk_prot->sockets_allocated)
                  atomic_inc(newsk->sk_prot->sockets_allocated);
      }
out:
      return newsk;
}

EXPORT_SYMBOL_GPL(sk_clone);

void __init sk_init(void)
{
      if (num_physpages <= 4096) {
            sysctl_wmem_max = 32767;
            sysctl_rmem_max = 32767;
            sysctl_wmem_default = 32767;
            sysctl_rmem_default = 32767;
      } else if (num_physpages >= 131072) {
            sysctl_wmem_max = 131071;
            sysctl_rmem_max = 131071;
      }
}

/*
 *    Simple resource managers for sockets.
 */


/* 
 * Write buffer destructor automatically called from kfree_skb. 
 */
void sock_wfree(struct sk_buff *skb)
{
      struct sock *sk = skb->sk;

      /* In case it might be waiting for more memory. */
      atomic_sub(skb->truesize, &sk->sk_wmem_alloc);
      if (!sock_flag(sk, SOCK_USE_WRITE_QUEUE))
            sk->sk_write_space(sk);
      sock_put(sk);
}

/* 
 * Read buffer destructor automatically called from kfree_skb. 
 */
void sock_rfree(struct sk_buff *skb)
{
      struct sock *sk = skb->sk;

      atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
}


int sock_i_uid(struct sock *sk)
{
      int uid;

      read_lock(&sk->sk_callback_lock);
      uid = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_uid : 0;
      read_unlock(&sk->sk_callback_lock);
      return uid;
}

unsigned long sock_i_ino(struct sock *sk)
{
      unsigned long ino;

      read_lock(&sk->sk_callback_lock);
      ino = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_ino : 0;
      read_unlock(&sk->sk_callback_lock);
      return ino;
}

/*
 * Allocate a skb from the socket's send buffer.
 */
struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
                       gfp_t priority)
{
      if (force || atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
            struct sk_buff * skb = alloc_skb(size, priority);
            if (skb) {
                  skb_set_owner_w(skb, sk);
                  return skb;
            }
      }
      return NULL;
}

/*
 * Allocate a skb from the socket's receive buffer.
 */ 
struct sk_buff *sock_rmalloc(struct sock *sk, unsigned long size, int force,
                       gfp_t priority)
{
      if (force || atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
            struct sk_buff *skb = alloc_skb(size, priority);
            if (skb) {
                  skb_set_owner_r(skb, sk);
                  return skb;
            }
      }
      return NULL;
}

/* 
 * Allocate a memory block from the socket's option memory buffer.
 */ 
void *sock_kmalloc(struct sock *sk, int size, gfp_t priority)
{
      if ((unsigned)size <= sysctl_optmem_max &&
          atomic_read(&sk->sk_omem_alloc) + size < sysctl_optmem_max) {
            void *mem;
            /* First do the add, to avoid the race if kmalloc
             * might sleep.
             */
            atomic_add(size, &sk->sk_omem_alloc);
            mem = kmalloc(size, priority);
            if (mem)
                  return mem;
            atomic_sub(size, &sk->sk_omem_alloc);
      }
      return NULL;
}

/*
 * Free an option memory block.
 */
void sock_kfree_s(struct sock *sk, void *mem, int size)
{
      kfree(mem);
      atomic_sub(size, &sk->sk_omem_alloc);
}

/* It is almost wait_for_tcp_memory minus release_sock/lock_sock.
   I think, these locks should be removed for datagram sockets.
 */
static long sock_wait_for_wmem(struct sock * sk, long timeo)
{
      DEFINE_WAIT(wait);

      clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
      for (;;) {
            if (!timeo)
                  break;
            if (signal_pending(current))
                  break;
            set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
            if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf)
                  break;
            if (sk->sk_shutdown & SEND_SHUTDOWN)
                  break;
            if (sk->sk_err)
                  break;
            timeo = schedule_timeout(timeo);
      }
      finish_wait(sk->sk_sleep, &wait);
      return timeo;
}


/*
 *    Generic send/receive buffer handlers
 */

static struct sk_buff *sock_alloc_send_pskb(struct sock *sk,
                                  unsigned long header_len,
                                  unsigned long data_len,
                                  int noblock, int *errcode)
{
      struct sk_buff *skb;
      gfp_t gfp_mask;
      long timeo;
      int err;

      gfp_mask = sk->sk_allocation;
      if (gfp_mask & __GFP_WAIT)
            gfp_mask |= __GFP_REPEAT;

      timeo = sock_sndtimeo(sk, noblock);
      while (1) {
            err = sock_error(sk);
            if (err != 0)
                  goto failure;

            err = -EPIPE;
            if (sk->sk_shutdown & SEND_SHUTDOWN)
                  goto failure;

            if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
                  skb = alloc_skb(header_len, sk->sk_allocation);
                  if (skb) {
                        int npages;
                        int i;

                        /* No pages, we're done... */
                        if (!data_len)
                              break;

                        npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
                        skb->truesize += data_len;
                        skb_shinfo(skb)->nr_frags = npages;
                        for (i = 0; i < npages; i++) {
                              struct page *page;
                              skb_frag_t *frag;

                              page = alloc_pages(sk->sk_allocation, 0);
                              if (!page) {
                                    err = -ENOBUFS;
                                    skb_shinfo(skb)->nr_frags = i;
                                    kfree_skb(skb);
                                    goto failure;
                              }

                              frag = &skb_shinfo(skb)->frags[i];
                              frag->page = page;
                              frag->page_offset = 0;
                              frag->size = (data_len >= PAGE_SIZE ?
                                          PAGE_SIZE :
                                          data_len);
                              data_len -= PAGE_SIZE;
                        }

                        /* Full success... */
                        break;
                  }
                  err = -ENOBUFS;
                  goto failure;
            }
            set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
            set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
            err = -EAGAIN;
            if (!timeo)
                  goto failure;
            if (signal_pending(current))
                  goto interrupted;
            timeo = sock_wait_for_wmem(sk, timeo);
      }

      skb_set_owner_w(skb, sk);
      return skb;

interrupted:
      err = sock_intr_errno(timeo);
failure:
      *errcode = err;
      return NULL;
}

struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size, 
                            int noblock, int *errcode)
{
      return sock_alloc_send_pskb(sk, size, 0, noblock, errcode);
}

static void __lock_sock(struct sock *sk)
{
      DEFINE_WAIT(wait);

      for(;;) {
            prepare_to_wait_exclusive(&sk->sk_lock.wq, &wait,
                              TASK_UNINTERRUPTIBLE);
            spin_unlock_bh(&sk->sk_lock.slock);
            schedule();
            spin_lock_bh(&sk->sk_lock.slock);
            if(!sock_owned_by_user(sk))
                  break;
      }
      finish_wait(&sk->sk_lock.wq, &wait);
}

static void __release_sock(struct sock *sk)
{
      struct sk_buff *skb = sk->sk_backlog.head;

      do {
            sk->sk_backlog.head = sk->sk_backlog.tail = NULL;
            bh_unlock_sock(sk);

            do {
                  struct sk_buff *next = skb->next;

                  skb->next = NULL;
                  sk->sk_backlog_rcv(sk, skb);

                  /*
                   * We are in process context here with softirqs
                   * disabled, use cond_resched_softirq() to preempt.
                   * This is safe to do because we've taken the backlog
                   * queue private:
                   */
                  cond_resched_softirq();

                  skb = next;
            } while (skb != NULL);

            bh_lock_sock(sk);
      } while((skb = sk->sk_backlog.head) != NULL);
}

/**
 * sk_wait_data - wait for data to arrive at sk_receive_queue
 * @sk:    sock to wait on
 * @timeo: for how long
 *
 * Now socket state including sk->sk_err is changed only under lock,
 * hence we may omit checks after joining wait queue.
 * We check receive queue before schedule() only as optimization;
 * it is very likely that release_sock() added new data.
 */
int sk_wait_data(struct sock *sk, long *timeo)
{
      int rc;
      DEFINE_WAIT(wait);

      prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
      set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
      rc = sk_wait_event(sk, timeo, !skb_queue_empty(&sk->sk_receive_queue));
      clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
      finish_wait(sk->sk_sleep, &wait);
      return rc;
}

EXPORT_SYMBOL(sk_wait_data);

/*
 * Set of default routines for initialising struct proto_ops when
 * the protocol does not support a particular function. In certain
 * cases where it makes no sense for a protocol to have a "do nothing"
 * function, some default processing is provided.
 */

int sock_no_bind(struct socket *sock, struct sockaddr *saddr, int len)
{
      return -EOPNOTSUPP;
}

int sock_no_connect(struct socket *sock, struct sockaddr *saddr, 
                int len, int flags)
{
      return -EOPNOTSUPP;
}

int sock_no_socketpair(struct socket *sock1, struct socket *sock2)
{
      return -EOPNOTSUPP;
}

int sock_no_accept(struct socket *sock, struct socket *newsock, int flags)
{
      return -EOPNOTSUPP;
}

int sock_no_getname(struct socket *sock, struct sockaddr *saddr, 
                int *len, int peer)
{
      return -EOPNOTSUPP;
}

unsigned int sock_no_poll(struct file * file, struct socket *sock, poll_table *pt)
{
      return 0;
}

int sock_no_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
      return -EOPNOTSUPP;
}

int sock_no_listen(struct socket *sock, int backlog)
{
      return -EOPNOTSUPP;
}

int sock_no_shutdown(struct socket *sock, int how)
{
      return -EOPNOTSUPP;
}

int sock_no_setsockopt(struct socket *sock, int level, int optname,
                char __user *optval, int optlen)
{
      return -EOPNOTSUPP;
}

int sock_no_getsockopt(struct socket *sock, int level, int optname,
                char __user *optval, int __user *optlen)
{
      return -EOPNOTSUPP;
}

int sock_no_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
                size_t len)
{
      return -EOPNOTSUPP;
}

int sock_no_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
                size_t len, int flags)
{
      return -EOPNOTSUPP;
}

int sock_no_mmap(struct file *file, struct socket *sock, struct vm_area_struct *vma)
{
      /* Mirror missing mmap method error code */
      return -ENODEV;
}

ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags)
{
      ssize_t res;
      struct msghdr msg = {.msg_flags = flags};
      struct kvec iov;
      char *kaddr = kmap(page);
      iov.iov_base = kaddr + offset;
      iov.iov_len = size;
      res = kernel_sendmsg(sock, &msg, &iov, 1, size);
      kunmap(page);
      return res;
}

/*
 *    Default Socket Callbacks
 */

static void sock_def_wakeup(struct sock *sk)
{
      read_lock(&sk->sk_callback_lock);
      if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
            wake_up_interruptible_all(sk->sk_sleep);
      read_unlock(&sk->sk_callback_lock);
}

static void sock_def_error_report(struct sock *sk)
{
      read_lock(&sk->sk_callback_lock);
      if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
            wake_up_interruptible(sk->sk_sleep);
      sk_wake_async(sk,0,POLL_ERR); 
      read_unlock(&sk->sk_callback_lock);
}

static void sock_def_readable(struct sock *sk, int len)
{
      read_lock(&sk->sk_callback_lock);
      if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
            wake_up_interruptible(sk->sk_sleep);
      sk_wake_async(sk,1,POLL_IN);
      read_unlock(&sk->sk_callback_lock);
}

static void sock_def_write_space(struct sock *sk)
{
      read_lock(&sk->sk_callback_lock);

      /* Do not wake up a writer until he can make "significant"
       * progress.  --DaveM
       */
      if((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
            if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
                  wake_up_interruptible(sk->sk_sleep);

            /* Should agree with poll, otherwise some programs break */
            if (sock_writeable(sk))
                  sk_wake_async(sk, 2, POLL_OUT);
      }

      read_unlock(&sk->sk_callback_lock);
}

static void sock_def_destruct(struct sock *sk)
{
      kfree(sk->sk_protinfo);
}

void sk_send_sigurg(struct sock *sk)
{
      if (sk->sk_socket && sk->sk_socket->file)
            if (send_sigurg(&sk->sk_socket->file->f_owner))
                  sk_wake_async(sk, 3, POLL_PRI);
}

void sk_reset_timer(struct sock *sk, struct timer_list* timer,
                unsigned long expires)
{
      if (!mod_timer(timer, expires))
            sock_hold(sk);
}

EXPORT_SYMBOL(sk_reset_timer);

void sk_stop_timer(struct sock *sk, struct timer_list* timer)
{
      if (timer_pending(timer) && del_timer(timer))
            __sock_put(sk);
}

EXPORT_SYMBOL(sk_stop_timer);

void sock_init_data(struct socket *sock, struct sock *sk)
{
      skb_queue_head_init(&sk->sk_receive_queue);
      skb_queue_head_init(&sk->sk_write_queue);
      skb_queue_head_init(&sk->sk_error_queue);
#ifdef CONFIG_NET_DMA
      skb_queue_head_init(&sk->sk_async_wait_queue);
#endif

      sk->sk_send_head  =     NULL;

      init_timer(&sk->sk_timer);
      
      sk->sk_allocation =     GFP_KERNEL;
      sk->sk_rcvbuf           =     sysctl_rmem_default;
      sk->sk_sndbuf           =     sysctl_wmem_default;
      sk->sk_state            =     TCP_CLOSE;
      sk->sk_socket           =     sock;

      sock_set_flag(sk, SOCK_ZAPPED);

      if(sock)
      {
            sk->sk_type =     sock->type;
            sk->sk_sleep      =     &sock->wait;
            sock->sk    =     sk;
      } else
            sk->sk_sleep      =     NULL;

      rwlock_init(&sk->sk_dst_lock);
      rwlock_init(&sk->sk_callback_lock);
      lockdep_set_class(&sk->sk_callback_lock,
                     af_callback_keys + sk->sk_family);

      sk->sk_state_change     =     sock_def_wakeup;
      sk->sk_data_ready =     sock_def_readable;
      sk->sk_write_space      =     sock_def_write_space;
      sk->sk_error_report     =     sock_def_error_report;
      sk->sk_destruct         =     sock_def_destruct;

      sk->sk_sndmsg_page      =     NULL;
      sk->sk_sndmsg_off =     0;

      sk->sk_peercred.pid     =     0;
      sk->sk_peercred.uid     =     -1;
      sk->sk_peercred.gid     =     -1;
      sk->sk_write_pending    =     0;
      sk->sk_rcvlowat         =     1;
      sk->sk_rcvtimeo         =     MAX_SCHEDULE_TIMEOUT;
      sk->sk_sndtimeo         =     MAX_SCHEDULE_TIMEOUT;

      sk->sk_stamp.tv_sec     = -1L;
      sk->sk_stamp.tv_usec    = -1L;

      atomic_set(&sk->sk_refcnt, 1);
}

void fastcall lock_sock(struct sock *sk)
{
      might_sleep();
      spin_lock_bh(&sk->sk_lock.slock);
      if (sk->sk_lock.owner)
            __lock_sock(sk);
      sk->sk_lock.owner = (void *)1;
      spin_unlock(&sk->sk_lock.slock);
      /*
       * The sk_lock has mutex_lock() semantics here:
       */
      mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
      local_bh_enable();
}

EXPORT_SYMBOL(lock_sock);

void fastcall release_sock(struct sock *sk)
{
      /*
       * The sk_lock has mutex_unlock() semantics:
       */
      mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);

      spin_lock_bh(&sk->sk_lock.slock);
      if (sk->sk_backlog.tail)
            __release_sock(sk);
      sk->sk_lock.owner = NULL;
      if (waitqueue_active(&sk->sk_lock.wq))
            wake_up(&sk->sk_lock.wq);
      spin_unlock_bh(&sk->sk_lock.slock);
}
EXPORT_SYMBOL(release_sock);

int sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp)
{ 
      if (!sock_flag(sk, SOCK_TIMESTAMP))
            sock_enable_timestamp(sk);
      if (sk->sk_stamp.tv_sec == -1) 
            return -ENOENT;
      if (sk->sk_stamp.tv_sec == 0)
            do_gettimeofday(&sk->sk_stamp);
      return copy_to_user(userstamp, &sk->sk_stamp, sizeof(struct timeval)) ?
            -EFAULT : 0; 
} 
EXPORT_SYMBOL(sock_get_timestamp);

void sock_enable_timestamp(struct sock *sk)
{     
      if (!sock_flag(sk, SOCK_TIMESTAMP)) { 
            sock_set_flag(sk, SOCK_TIMESTAMP);
            net_enable_timestamp();
      }
}
EXPORT_SYMBOL(sock_enable_timestamp); 

/*
 *    Get a socket option on an socket.
 *
 *    FIX: POSIX 1003.1g is very ambiguous here. It states that
 *    asynchronous errors should be reported by getsockopt. We assume
 *    this means if you specify SO_ERROR (otherwise whats the point of it).
 */
int sock_common_getsockopt(struct socket *sock, int level, int optname,
                     char __user *optval, int __user *optlen)
{
      struct sock *sk = sock->sk;

      return sk->sk_prot->getsockopt(sk, level, optname, optval, optlen);
}

EXPORT_SYMBOL(sock_common_getsockopt);

#ifdef CONFIG_COMPAT
int compat_sock_common_getsockopt(struct socket *sock, int level, int optname,
                          char __user *optval, int __user *optlen)
{
      struct sock *sk = sock->sk;

      if (sk->sk_prot->compat_setsockopt != NULL)
            return sk->sk_prot->compat_getsockopt(sk, level, optname,
                                          optval, optlen);
      return sk->sk_prot->getsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_sock_common_getsockopt);
#endif

int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
                  struct msghdr *msg, size_t size, int flags)
{
      struct sock *sk = sock->sk;
      int addr_len = 0;
      int err;

      err = sk->sk_prot->recvmsg(iocb, sk, msg, size, flags & MSG_DONTWAIT,
                           flags & ~MSG_DONTWAIT, &addr_len);
      if (err >= 0)
            msg->msg_namelen = addr_len;
      return err;
}

EXPORT_SYMBOL(sock_common_recvmsg);

/*
 *    Set socket options on an inet socket.
 */
int sock_common_setsockopt(struct socket *sock, int level, int optname,
                     char __user *optval, int optlen)
{
      struct sock *sk = sock->sk;

      return sk->sk_prot->setsockopt(sk, level, optname, optval, optlen);
}

EXPORT_SYMBOL(sock_common_setsockopt);

#ifdef CONFIG_COMPAT
int compat_sock_common_setsockopt(struct socket *sock, int level, int optname,
                          char __user *optval, int optlen)
{
      struct sock *sk = sock->sk;

      if (sk->sk_prot->compat_setsockopt != NULL)
            return sk->sk_prot->compat_setsockopt(sk, level, optname,
                                          optval, optlen);
      return sk->sk_prot->setsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_sock_common_setsockopt);
#endif

void sk_common_release(struct sock *sk)
{
      if (sk->sk_prot->destroy)
            sk->sk_prot->destroy(sk);

      /*
       * Observation: when sock_common_release is called, processes have
       * no access to socket. But net still has.
       * Step one, detach it from networking:
       *
       * A. Remove from hash tables.
       */

      sk->sk_prot->unhash(sk);

      /*
       * In this point socket cannot receive new packets, but it is possible
       * that some packets are in flight because some CPU runs receiver and
       * did hash table lookup before we unhashed socket. They will achieve
       * receive queue and will be purged by socket destructor.
       *
       * Also we still have packets pending on receive queue and probably,
       * our own packets waiting in device queues. sock_destroy will drain
       * receive queue, but transmitted packets will delay socket destruction
       * until the last reference will be released.
       */

      sock_orphan(sk);

      xfrm_sk_free_policy(sk);

      sk_refcnt_debug_release(sk);
      sock_put(sk);
}

EXPORT_SYMBOL(sk_common_release);

static DEFINE_RWLOCK(proto_list_lock);
static LIST_HEAD(proto_list);

int proto_register(struct proto *prot, int alloc_slab)
{
      char *request_sock_slab_name = NULL;
      char *timewait_sock_slab_name;
      int rc = -ENOBUFS;

      if (alloc_slab) {
            prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
                                     SLAB_HWCACHE_ALIGN, NULL, NULL);

            if (prot->slab == NULL) {
                  printk(KERN_CRIT "%s: Can't create sock SLAB cache!\n",
                         prot->name);
                  goto out;
            }

            if (prot->rsk_prot != NULL) {
                  static const char mask[] = "request_sock_%s";

                  request_sock_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
                  if (request_sock_slab_name == NULL)
                        goto out_free_sock_slab;

                  sprintf(request_sock_slab_name, mask, prot->name);
                  prot->rsk_prot->slab = kmem_cache_create(request_sock_slab_name,
                                                 prot->rsk_prot->obj_size, 0,
                                                 SLAB_HWCACHE_ALIGN, NULL, NULL);

                  if (prot->rsk_prot->slab == NULL) {
                        printk(KERN_CRIT "%s: Can't create request sock SLAB cache!\n",
                               prot->name);
                        goto out_free_request_sock_slab_name;
                  }
            }

            if (prot->twsk_prot != NULL) {
                  static const char mask[] = "tw_sock_%s";

                  timewait_sock_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);

                  if (timewait_sock_slab_name == NULL)
                        goto out_free_request_sock_slab;

                  sprintf(timewait_sock_slab_name, mask, prot->name);
                  prot->twsk_prot->twsk_slab =
                        kmem_cache_create(timewait_sock_slab_name,
                                      prot->twsk_prot->twsk_obj_size,
                                      0, SLAB_HWCACHE_ALIGN,
                                      NULL, NULL);
                  if (prot->twsk_prot->twsk_slab == NULL)
                        goto out_free_timewait_sock_slab_name;
            }
      }

      write_lock(&proto_list_lock);
      list_add(&prot->node, &proto_list);
      write_unlock(&proto_list_lock);
      rc = 0;
out:
      return rc;
out_free_timewait_sock_slab_name:
      kfree(timewait_sock_slab_name);
out_free_request_sock_slab:
      if (prot->rsk_prot && prot->rsk_prot->slab) {
            kmem_cache_destroy(prot->rsk_prot->slab);
            prot->rsk_prot->slab = NULL;
      }
out_free_request_sock_slab_name:
      kfree(request_sock_slab_name);
out_free_sock_slab:
      kmem_cache_destroy(prot->slab);
      prot->slab = NULL;
      goto out;
}

EXPORT_SYMBOL(proto_register);

void proto_unregister(struct proto *prot)
{
      write_lock(&proto_list_lock);
      list_del(&prot->node);
      write_unlock(&proto_list_lock);

      if (prot->slab != NULL) {
            kmem_cache_destroy(prot->slab);
            prot->slab = NULL;
      }

      if (prot->rsk_prot != NULL && prot->rsk_prot->slab != NULL) {
            const char *name = kmem_cache_name(prot->rsk_prot->slab);

            kmem_cache_destroy(prot->rsk_prot->slab);
            kfree(name);
            prot->rsk_prot->slab = NULL;
      }

      if (prot->twsk_prot != NULL && prot->twsk_prot->twsk_slab != NULL) {
            const char *name = kmem_cache_name(prot->twsk_prot->twsk_slab);

            kmem_cache_destroy(prot->twsk_prot->twsk_slab);
            kfree(name);
            prot->twsk_prot->twsk_slab = NULL;
      }
}

EXPORT_SYMBOL(proto_unregister);

#ifdef CONFIG_PROC_FS
static inline struct proto *__proto_head(void)
{
      return list_entry(proto_list.next, struct proto, node);
}

static inline struct proto *proto_head(void)
{
      return list_empty(&proto_list) ? NULL : __proto_head();
}

static inline struct proto *proto_next(struct proto *proto)
{
      return proto->node.next == &proto_list ? NULL :
            list_entry(proto->node.next, struct proto, node);
}

static inline struct proto *proto_get_idx(loff_t pos)
{
      struct proto *proto;
      loff_t i = 0;

      list_for_each_entry(proto, &proto_list, node)
            if (i++ == pos)
                  goto out;

      proto = NULL;
out:
      return proto;
}

static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
{
      read_lock(&proto_list_lock);
      return *pos ? proto_get_idx(*pos - 1) : SEQ_START_TOKEN;
}

static void *proto_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
      ++*pos;
      return v == SEQ_START_TOKEN ? proto_head() : proto_next(v);
}

static void proto_seq_stop(struct seq_file *seq, void *v)
{
      read_unlock(&proto_list_lock);
}

static char proto_method_implemented(const void *method)
{
      return method == NULL ? 'n' : 'y';
}

static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
{
      seq_printf(seq, "%-9s %4u %6d  %6d   %-3s %6u   %-3s  %-10s "
                  "%2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c\n",
               proto->name,
               proto->obj_size,
               proto->sockets_allocated != NULL ? atomic_read(proto->sockets_allocated) : -1,
               proto->memory_allocated != NULL ? atomic_read(proto->memory_allocated) : -1,
               proto->memory_pressure != NULL ? *proto->memory_pressure ? "yes" : "no" : "NI",
               proto->max_header,
               proto->slab == NULL ? "no" : "yes",
               module_name(proto->owner),
               proto_method_implemented(proto->close),
               proto_method_implemented(proto->connect),
               proto_method_implemented(proto->disconnect),
               proto_method_implemented(proto->accept),
               proto_method_implemented(proto->ioctl),
               proto_method_implemented(proto->init),
               proto_method_implemented(proto->destroy),
               proto_method_implemented(proto->shutdown),
               proto_method_implemented(proto->setsockopt),
               proto_method_implemented(proto->getsockopt),
               proto_method_implemented(proto->sendmsg),
               proto_method_implemented(proto->recvmsg),
               proto_method_implemented(proto->sendpage),
               proto_method_implemented(proto->bind),
               proto_method_implemented(proto->backlog_rcv),
               proto_method_implemented(proto->hash),
               proto_method_implemented(proto->unhash),
               proto_method_implemented(proto->get_port),
               proto_method_implemented(proto->enter_memory_pressure));
}

static int proto_seq_show(struct seq_file *seq, void *v)
{
      if (v == SEQ_START_TOKEN)
            seq_printf(seq, "%-9s %-4s %-8s %-6s %-5s %-7s %-4s %-10s %s",
                     "protocol",
                     "size",
                     "sockets",
                     "memory",
                     "press",
                     "maxhdr",
                     "slab",
                     "module",
                     "cl co di ac io in de sh ss gs se re sp bi br ha uh gp em\n");
      else
            proto_seq_printf(seq, v);
      return 0;
}

static struct seq_operations proto_seq_ops = {
      .start  = proto_seq_start,
      .next   = proto_seq_next,
      .stop   = proto_seq_stop,
      .show   = proto_seq_show,
};

static int proto_seq_open(struct inode *inode, struct file *file)
{
      return seq_open(file, &proto_seq_ops);
}

static struct file_operations proto_seq_fops = {
      .owner            = THIS_MODULE,
      .open       = proto_seq_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init proto_init(void)
{
      /* register /proc/net/protocols */
      return proc_net_fops_create("protocols", S_IRUGO, &proto_seq_fops) == NULL ? -ENOBUFS : 0;
}

subsys_initcall(proto_init);

#endif /* PROC_FS */

EXPORT_SYMBOL(sk_alloc);
EXPORT_SYMBOL(sk_free);
EXPORT_SYMBOL(sk_send_sigurg);
EXPORT_SYMBOL(sock_alloc_send_skb);
EXPORT_SYMBOL(sock_init_data);
EXPORT_SYMBOL(sock_kfree_s);
EXPORT_SYMBOL(sock_kmalloc);
EXPORT_SYMBOL(sock_no_accept);
EXPORT_SYMBOL(sock_no_bind);
EXPORT_SYMBOL(sock_no_connect);
EXPORT_SYMBOL(sock_no_getname);
EXPORT_SYMBOL(sock_no_getsockopt);
EXPORT_SYMBOL(sock_no_ioctl);
EXPORT_SYMBOL(sock_no_listen);
EXPORT_SYMBOL(sock_no_mmap);
EXPORT_SYMBOL(sock_no_poll);
EXPORT_SYMBOL(sock_no_recvmsg);
EXPORT_SYMBOL(sock_no_sendmsg);
EXPORT_SYMBOL(sock_no_sendpage);
EXPORT_SYMBOL(sock_no_setsockopt);
EXPORT_SYMBOL(sock_no_shutdown);
EXPORT_SYMBOL(sock_no_socketpair);
EXPORT_SYMBOL(sock_rfree);
EXPORT_SYMBOL(sock_setsockopt);
EXPORT_SYMBOL(sock_wfree);
EXPORT_SYMBOL(sock_wmalloc);
EXPORT_SYMBOL(sock_i_uid);
EXPORT_SYMBOL(sock_i_ino);
EXPORT_SYMBOL(sysctl_optmem_max);
#ifdef CONFIG_SYSCTL
EXPORT_SYMBOL(sysctl_rmem_max);
EXPORT_SYMBOL(sysctl_wmem_max);
#endif

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