/*
 * 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.
 *
 *
 * 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 <linux/highmem.h>

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

#include <linux/netdevice.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/net_namespace.h>
#include <net/request_sock.h>
#include <net/sock.h>
#include <linux/net_tstamp.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];

/*
 * 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-AF_RDS"   , "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-AF_CAN"      ,
  "sk_lock-AF_TIPC"  , "sk_lock-AF_BLUETOOTH", "sk_lock-IUCV"        ,
  "sk_lock-AF_RXRPC" , "sk_lock-AF_ISDN"     , "sk_lock-AF_PHONET"   ,
  "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-AF_RDS"   , "slock-AF_SNA"      , "slock-AF_IRDA"     ,
  "slock-AF_PPPOX" , "slock-AF_WANPIPE"  , "slock-AF_LLC"      ,
  "slock-27"       , "slock-28"          , "slock-AF_CAN"      ,
  "slock-AF_TIPC"  , "slock-AF_BLUETOOTH", "slock-AF_IUCV"     ,
  "slock-AF_RXRPC" , "slock-AF_ISDN"     , "slock-AF_PHONET"   ,
  "slock-AF_MAX"
};
static const char *af_family_clock_key_strings[AF_MAX+1] = {
  "clock-AF_UNSPEC", "clock-AF_UNIX"     , "clock-AF_INET"     ,
  "clock-AF_AX25"  , "clock-AF_IPX"      , "clock-AF_APPLETALK",
  "clock-AF_NETROM", "clock-AF_BRIDGE"   , "clock-AF_ATMPVC"   ,
  "clock-AF_X25"   , "clock-AF_INET6"    , "clock-AF_ROSE"     ,
  "clock-AF_DECnet", "clock-AF_NETBEUI"  , "clock-AF_SECURITY" ,
  "clock-AF_KEY"   , "clock-AF_NETLINK"  , "clock-AF_PACKET"   ,
  "clock-AF_ASH"   , "clock-AF_ECONET"   , "clock-AF_ATMSVC"   ,
  "clock-AF_RDS"   , "clock-AF_SNA"      , "clock-AF_IRDA"     ,
  "clock-AF_PPPOX" , "clock-AF_WANPIPE"  , "clock-AF_LLC"      ,
  "clock-27"       , "clock-28"          , "clock-AF_CAN"      ,
  "clock-AF_TIPC"  , "clock-AF_BLUETOOTH", "clock-AF_IUCV"     ,
  "clock-AF_RXRPC" , "clock-AF_ISDN"     , "clock-AF_PHONET"   ,
  "clock-AF_MAX"
};

/*
 * 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 __read_mostly = SK_WMEM_MAX;
__u32 sysctl_rmem_max __read_mostly = SK_RMEM_MAX;
__u32 sysctl_wmem_default __read_mostly = SK_WMEM_MAX;
__u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX;

/* Maximal space eaten by iovec or ancilliary data plus some space */
int sysctl_optmem_max __read_mostly = 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;
        if (tv.tv_usec < 0 || tv.tv_usec >= USEC_PER_SEC)
                return -EDOM;

        if (tv.tv_sec < 0) {
                static int warned __read_mostly;

                *timeo_p = 0;
                if (warned < 10 && net_ratelimit()) {
                        warned++;
                        printk(KERN_INFO "sock_set_timeout: `%s' (pid %d) "
                               "tries to set negative timeout\n",
                                current->comm, task_pid_nr(current));
                }
                return 0;
        }
        *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, int flag)
{
        if (sock_flag(sk, flag)) {
                sock_reset_flag(sk, flag);
                if (!sock_flag(sk, SOCK_TIMESTAMP) &&
                    !sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE)) {
                        net_disable_timestamp();
                }
        }
}


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

        /* Cast sk->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;
        }

        err = sk_filter(sk, skb);
        if (err)
                goto out;

        if (!sk_rmem_schedule(sk, skb->truesize)) {
                err = -ENOBUFS;
                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, const int nested)
{
        int rc = NET_RX_SUCCESS;

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

        skb->dev = NULL;

        if (nested)
                bh_lock_sock_nested(sk);
        else
                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_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);

static int sock_bindtodevice(struct sock *sk, char __user *optval, int optlen)
{
        int ret = -ENOPROTOOPT;
#ifdef CONFIG_NETDEVICES
        struct net *net = sock_net(sk);
        char devname[IFNAMSIZ];
        int index;

        /* Sorry... */
        ret = -EPERM;
        if (!capable(CAP_NET_RAW))
                goto out;

        ret = -EINVAL;
        if (optlen < 0)
                goto out;

        /* 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 (optlen > IFNAMSIZ - 1)
                optlen = IFNAMSIZ - 1;
        memset(devname, 0, sizeof(devname));

        ret = -EFAULT;
        if (copy_from_user(devname, optval, optlen))
                goto out;

        if (devname[0] == '\0') {
                index = 0;
        } else {
                struct net_device *dev = dev_get_by_name(net, devname);

                ret = -ENODEV;
                if (!dev)
                        goto out;

                index = dev->ifindex;
                dev_put(dev);
        }

        lock_sock(sk);
        sk->sk_bound_dev_if = index;
        sk_dst_reset(sk);
        release_sock(sk);

        ret = 0;

out:
#endif

        return ret;
}

static inline void sock_valbool_flag(struct sock *sk, int bit, int valbool)
{
        if (valbool)
                sock_set_flag(sk, bit);
        else
                sock_reset_flag(sk, bit);
}

/*
 *      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;
        int val;
        int valbool;
        struct linger ling;
        int ret = 0;

        /*
         *      Options without arguments
         */

        if (optname == SO_BINDTODEVICE)
                return sock_bindtodevice(sk, optval, optlen);

        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
                        sock_valbool_flag(sk, SOCK_DBG, valbool);
                break;
        case SO_REUSEADDR:
                sk->sk_reuse = valbool;
                break;
        case SO_TYPE:
        case SO_ERROR:
                ret = -ENOPROTOOPT;
                break;
        case SO_DONTROUTE:
                sock_valbool_flag(sk, SOCK_LOCALROUTE, valbool);
                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:
        case SO_TIMESTAMPNS:
                if (valbool)  {
                        if (optname == SO_TIMESTAMP)
                                sock_reset_flag(sk, SOCK_RCVTSTAMPNS);
                        else
                                sock_set_flag(sk, SOCK_RCVTSTAMPNS);
                        sock_set_flag(sk, SOCK_RCVTSTAMP);
                        sock_enable_timestamp(sk, SOCK_TIMESTAMP);
                } else {
                        sock_reset_flag(sk, SOCK_RCVTSTAMP);
                        sock_reset_flag(sk, SOCK_RCVTSTAMPNS);
                }
                break;

        case SO_TIMESTAMPING:
                if (val & ~SOF_TIMESTAMPING_MASK) {
                        ret = EINVAL;
                        break;
                }
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE,
                                  val & SOF_TIMESTAMPING_TX_HARDWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE,
                                  val & SOF_TIMESTAMPING_TX_SOFTWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_RX_HARDWARE,
                                  val & SOF_TIMESTAMPING_RX_HARDWARE);
                if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
                        sock_enable_timestamp(sk,
                                              SOCK_TIMESTAMPING_RX_SOFTWARE);
                else
                        sock_disable_timestamp(sk,
                                               SOCK_TIMESTAMPING_RX_SOFTWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_SOFTWARE,
                                  val & SOF_TIMESTAMPING_SOFTWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE,
                                  val & SOF_TIMESTAMPING_SYS_HARDWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE,
                                  val & SOF_TIMESTAMPING_RAW_HARDWARE);
                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;

        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:
                ret = sk_detach_filter(sk);
                break;

        case SO_PASSSEC:
                if (valbool)
                        set_bit(SOCK_PASSSEC, &sock->flags);
                else
                        clear_bit(SOCK_PASSSEC, &sock->flags);
                break;
        case SO_MARK:
                if (!capable(CAP_NET_ADMIN))
                        ret = -EPERM;
                else {
                        sk->sk_mark = val;
                }
                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;

        memset(&v, 0, sizeof(v));

        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) &&
                                !sock_flag(sk, SOCK_RCVTSTAMPNS);
                break;

        case SO_TIMESTAMPNS:
                v.val = sock_flag(sk, SOCK_RCVTSTAMPNS);
                break;

        case SO_TIMESTAMPING:
                v.val = 0;
                if (sock_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE))
                        v.val |= SOF_TIMESTAMPING_TX_HARDWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE))
                        v.val |= SOF_TIMESTAMPING_TX_SOFTWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_RX_HARDWARE))
                        v.val |= SOF_TIMESTAMPING_RX_HARDWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE))
                        v.val |= SOF_TIMESTAMPING_RX_SOFTWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE))
                        v.val |= SOF_TIMESTAMPING_SOFTWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE))
                        v.val |= SOF_TIMESTAMPING_SYS_HARDWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE))
                        v.val |= SOF_TIMESTAMPING_RAW_HARDWARE;
                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);

        case SO_MARK:
                v.val = sk->sk_mark;
                break;

        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 inline void sock_lock_init(struct sock *sk)
{
        sock_lock_init_class_and_name(sk,
                        af_family_slock_key_strings[sk->sk_family],
                        af_family_slock_keys + sk->sk_family,
                        af_family_key_strings[sk->sk_family],
                        af_family_keys + sk->sk_family);
}

static void sock_copy(struct sock *nsk, const struct sock *osk)
{
#ifdef CONFIG_SECURITY_NETWORK
        void *sptr = nsk->sk_security;
#endif

        memcpy(nsk, osk, osk->sk_prot->obj_size);
#ifdef CONFIG_SECURITY_NETWORK
        nsk->sk_security = sptr;
        security_sk_clone(osk, nsk);
#endif
}

static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
                int family)
{
        struct sock *sk;
        struct kmem_cache *slab;

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

        if (sk != NULL) {
                if (security_sk_alloc(sk, family, priority))
                        goto out_free;

                if (!try_module_get(prot->owner))
                        goto out_free_sec;
        }

        return sk;

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

static void sk_prot_free(struct proto *prot, struct sock *sk)
{
        struct kmem_cache *slab;
        struct module *owner;

        owner = prot->owner;
        slab = prot->slab;

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

/**
 *      sk_alloc - All socket objects are allocated here
 *      @net: the applicable net namespace
 *      @family: protocol family
 *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 *      @prot: struct proto associated with this new sock instance
 */
struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
                      struct proto *prot)
{
        struct sock *sk;

        sk = sk_prot_alloc(prot, priority | __GFP_ZERO, family);
        if (sk) {
                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);
                sock_net_set(sk, get_net(net));

        }

        return sk;
}

void sk_free(struct sock *sk)
{
        struct sk_filter *filter;

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

        filter = rcu_dereference(sk->sk_filter);
        if (filter) {
                sk_filter_uncharge(sk, filter);
                rcu_assign_pointer(sk->sk_filter, NULL);
        }

        sock_disable_timestamp(sk, SOCK_TIMESTAMP);
        sock_disable_timestamp(sk, SOCK_TIMESTAMPING_RX_SOFTWARE);

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

        put_net(sock_net(sk));
        sk_prot_free(sk->sk_prot_creator, sk);
}

/*
 * Last sock_put should drop referrence to sk->sk_net. It has already
 * been dropped in sk_change_net. Taking referrence to stopping namespace
 * is not an option.
 * Take referrence to a socket to remove it from hash _alive_ and after that
 * destroy it in the context of init_net.
 */
void sk_release_kernel(struct sock *sk)
{
        if (sk == NULL || sk->sk_socket == NULL)
                return;

        sock_hold(sk);
        sock_release(sk->sk_socket);
        release_net(sock_net(sk));
        sock_net_set(sk, get_net(&init_net));
        sock_put(sk);
}
EXPORT_SYMBOL(sk_release_kernel);

struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
{
        struct sock *newsk;

        newsk = sk_prot_alloc(sk->sk_prot, priority, sk->sk_family);
        if (newsk != NULL) {
                struct sk_filter *filter;

                sock_copy(newsk, sk);

                /* SANITY */
                get_net(sock_net(newsk));
                sk_node_init(&newsk->sk_node);
                sock_lock_init(newsk);
                bh_lock_sock(newsk);
                newsk->sk_backlog.head  = newsk->sk_backlog.tail = NULL;

                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_and_name(&newsk->sk_callback_lock,
                                af_callback_keys + newsk->sk_family,
                                af_family_clock_key_strings[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_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);
                sk_set_socket(newsk, NULL);
                newsk->sk_sleep  = NULL;

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

EXPORT_SYMBOL_GPL(sk_clone);

void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
{
        __sk_dst_set(sk, dst);
        sk->sk_route_caps = dst->dev->features;
        if (sk->sk_route_caps & NETIF_F_GSO)
                sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
        if (sk_can_gso(sk)) {
                if (dst->header_len) {
                        sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
                } else {
                        sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
                        sk->sk_gso_max_size = dst->dev->gso_max_size;
                }
        }
}
EXPORT_SYMBOL_GPL(sk_setup_caps);

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);
        sk_mem_uncharge(skb->sk, skb->truesize);
}


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
 */

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, gfp_mask);
                        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;
}
EXPORT_SYMBOL(sock_alloc_send_pskb);

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_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);

/**
 *      __sk_mem_schedule - increase sk_forward_alloc and memory_allocated
 *      @sk: socket
 *      @size: memory size to allocate
 *      @kind: allocation type
 *
 *      If kind is SK_MEM_SEND, it means wmem allocation. Otherwise it means
 *      rmem allocation. This function assumes that protocols which have
 *      memory_pressure use sk_wmem_queued as write buffer accounting.
 */
int __sk_mem_schedule(struct sock *sk, int size, int kind)
{
        struct proto *prot = sk->sk_prot;
        int amt = sk_mem_pages(size);
        int allocated;

        sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
        allocated = atomic_add_return(amt, prot->memory_allocated);

        /* Under limit. */
        if (allocated <= prot->sysctl_mem[0]) {
                if (prot->memory_pressure && *prot->memory_pressure)
                        *prot->memory_pressure = 0;
                return 1;
        }

        /* Under pressure. */
        if (allocated > prot->sysctl_mem[1])
                if (prot->enter_memory_pressure)
                        prot->enter_memory_pressure(sk);

        /* Over hard limit. */
        if (allocated > prot->sysctl_mem[2])
                goto suppress_allocation;

        /* guarantee minimum buffer size under pressure */
        if (kind == SK_MEM_RECV) {
                if (atomic_read(&sk->sk_rmem_alloc) < prot->sysctl_rmem[0])
                        return 1;
        } else { /* SK_MEM_SEND */
                if (sk->sk_type == SOCK_STREAM) {
                        if (sk->sk_wmem_queued < prot->sysctl_wmem[0])
                                return 1;
                } else if (atomic_read(&sk->sk_wmem_alloc) <
                           prot->sysctl_wmem[0])
                                return 1;
        }

        if (prot->memory_pressure) {
                int alloc;

                if (!*prot->memory_pressure)
                        return 1;
                alloc = percpu_counter_read_positive(prot->sockets_allocated);
                if (prot->sysctl_mem[2] > alloc *
                    sk_mem_pages(sk->sk_wmem_queued +
                                 atomic_read(&sk->sk_rmem_alloc) +
                                 sk->sk_forward_alloc))
                        return 1;
        }

suppress_allocation:

        if (kind == SK_MEM_SEND && sk->sk_type == SOCK_STREAM) {
                sk_stream_moderate_sndbuf(sk);

                /* Fail only if socket is _under_ its sndbuf.
                 * In this case we cannot block, so that we have to fail.
                 */
                if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
                        return 1;
        }

        /* Alas. Undo changes. */
        sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
        atomic_sub(amt, prot->memory_allocated);
        return 0;
}

EXPORT_SYMBOL(__sk_mem_schedule);

/**
 *      __sk_reclaim - reclaim memory_allocated
 *      @sk: socket
 */
void __sk_mem_reclaim(struct sock *sk)
{
        struct proto *prot = sk->sk_prot;

        atomic_sub(sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT,
                   prot->memory_allocated);
        sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;

        if (prot->memory_pressure && *prot->memory_pressure &&
            (atomic_read(prot->memory_allocated) < prot->sysctl_mem[0]))
                *prot->memory_pressure = 0;
}

EXPORT_SYMBOL(__sk_mem_reclaim);


/*
 * 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_poll(sk->sk_sleep, POLLERR);
        sk_wake_async(sk, SOCK_WAKE_IO, 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_sync_poll(sk->sk_sleep, POLLIN |
                                                POLLRDNORM | POLLRDBAND);
        sk_wake_async(sk, SOCK_WAKE_WAITD, 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_sync_poll(sk->sk_sleep, POLLOUT |
                                                POLLWRNORM | POLLWRBAND);

                /* Should agree with poll, otherwise some programs break */
                if (sock_writeable(sk))
                        sk_wake_async(sk, SOCK_WAKE_SPACE, 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, SOCK_WAKE_URG, 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_set_socket(sk, 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_and_name(&sk->sk_callback_lock,
                        af_callback_keys + sk->sk_family,
                        af_family_clock_key_strings[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 = ktime_set(-1L, 0);

        atomic_set(&sk->sk_refcnt, 1);
        atomic_set(&sk->sk_drops, 0);
}

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

EXPORT_SYMBOL(lock_sock_nested);

void 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.owned = 0;
        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)
{
        struct timeval tv;
        if (!sock_flag(sk, SOCK_TIMESTAMP))
                sock_enable_timestamp(sk, SOCK_TIMESTAMP);
        tv = ktime_to_timeval(sk->sk_stamp);
        if (tv.tv_sec == -1)
                return -ENOENT;
        if (tv.tv_sec == 0) {
                sk->sk_stamp = ktime_get_real();
                tv = ktime_to_timeval(sk->sk_stamp);
        }
        return copy_to_user(userstamp, &tv, sizeof(tv)) ? -EFAULT : 0;
}
EXPORT_SYMBOL(sock_get_timestamp);

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

void sock_enable_timestamp(struct sock *sk, int flag)
{
        if (!sock_flag(sk, flag)) {
                sock_set_flag(sk, flag);
                /*
                 * we just set one of the two flags which require net
                 * time stamping, but time stamping might have been on
                 * already because of the other one
                 */
                if (!sock_flag(sk,
                                flag == SOCK_TIMESTAMP ?
                                SOCK_TIMESTAMPING_RX_SOFTWARE :
                                SOCK_TIMESTAMP))
                        net_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_getsockopt != 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);

#ifdef CONFIG_PROC_FS
#define PROTO_INUSE_NR  64      /* should be enough for the first time */
struct prot_inuse {