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32 results

sock.c

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  • sock.c 73.49 KiB
    /*
     * 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.
     */
    
    #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
    
    #include <linux/capability.h>
    #include <linux/errno.h>
    #include <linux/errqueue.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 <linux/user_namespace.h>
    #include <linux/static_key.h>
    #include <linux/memcontrol.h>
    #include <linux/prefetch.h>
    
    #include <asm/uaccess.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 <net/cls_cgroup.h>
    #include <net/netprio_cgroup.h>
    
    #include <linux/filter.h>
    
    #include <trace/events/sock.h>
    
    #ifdef CONFIG_INET
    #include <net/tcp.h>
    #endif
    
    #include <net/busy_poll.h>
    
    static DEFINE_MUTEX(proto_list_mutex);
    static LIST_HEAD(proto_list);
    
    /**
     * sk_ns_capable - General socket capability test
     * @sk: Socket to use a capability on or through
     * @user_ns: The user namespace of the capability to use
     * @cap: The capability to use
     *
     * Test to see if the opener of the socket had when the socket was
     * created and the current process has the capability @cap in the user
     * namespace @user_ns.
     */
    bool sk_ns_capable(const struct sock *sk,
    		   struct user_namespace *user_ns, int cap)
    {
    	return file_ns_capable(sk->sk_socket->file, user_ns, cap) &&
    		ns_capable(user_ns, cap);
    }
    EXPORT_SYMBOL(sk_ns_capable);
    
    /**
     * sk_capable - Socket global capability test
     * @sk: Socket to use a capability on or through
     * @cap: The global capbility to use
     *
     * Test to see if the opener of the socket had when the socket was
     * created and the current process has the capability @cap in all user
     * namespaces.
     */
    bool sk_capable(const struct sock *sk, int cap)
    {
    	return sk_ns_capable(sk, &init_user_ns, cap);
    }
    EXPORT_SYMBOL(sk_capable);
    
    /**
     * sk_net_capable - Network namespace socket capability test
     * @sk: Socket to use a capability on or through
     * @cap: The capability to use
     *
     * Test to see if the opener of the socket had when the socke was created
     * and the current process has the capability @cap over the network namespace
     * the socket is a member of.
     */
    bool sk_net_capable(const struct sock *sk, int cap)
    {
    	return sk_ns_capable(sk, sock_net(sk)->user_ns, cap);
    }
    EXPORT_SYMBOL(sk_net_capable);
    
    
    #ifdef CONFIG_MEMCG_KMEM
    int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
    {
    	struct proto *proto;
    	int ret = 0;
    
    	mutex_lock(&proto_list_mutex);
    	list_for_each_entry(proto, &proto_list, node) {
    		if (proto->init_cgroup) {
    			ret = proto->init_cgroup(memcg, ss);
    			if (ret)
    				goto out;
    		}
    	}
    
    	mutex_unlock(&proto_list_mutex);
    	return ret;
    out:
    	list_for_each_entry_continue_reverse(proto, &proto_list, node)
    		if (proto->destroy_cgroup)
    			proto->destroy_cgroup(memcg);
    	mutex_unlock(&proto_list_mutex);
    	return ret;
    }
    
    void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg)
    {
    	struct proto *proto;
    
    	mutex_lock(&proto_list_mutex);
    	list_for_each_entry_reverse(proto, &proto_list, node)
    		if (proto->destroy_cgroup)
    			proto->destroy_cgroup(memcg);
    	mutex_unlock(&proto_list_mutex);
    }
    #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];
    
    #if defined(CONFIG_MEMCG_KMEM)
    struct static_key memcg_socket_limit_enabled;
    EXPORT_SYMBOL(memcg_socket_limit_enabled);
    #endif
    
    /*
     * 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 *const 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_IEEE802154", "sk_lock-AF_CAIF" , "sk_lock-AF_ALG"      ,
      "sk_lock-AF_NFC"   , "sk_lock-AF_VSOCK"    , "sk_lock-AF_MAX"
    };
    static const char *const 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_IEEE802154", "slock-AF_CAIF" , "slock-AF_ALG"      ,
      "slock-AF_NFC"   , "slock-AF_VSOCK"    ,"slock-AF_MAX"
    };
    static const char *const 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_IEEE802154", "clock-AF_CAIF" , "clock-AF_ALG"      ,
      "clock-AF_NFC"   , "clock-AF_VSOCK"    , "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	SKB_TRUESIZE(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;
    EXPORT_SYMBOL(sysctl_wmem_max);
    __u32 sysctl_rmem_max __read_mostly = SK_RMEM_MAX;
    EXPORT_SYMBOL(sysctl_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 ancillary data plus some space */
    int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512);
    EXPORT_SYMBOL(sysctl_optmem_max);
    
    struct static_key memalloc_socks = STATIC_KEY_INIT_FALSE;
    EXPORT_SYMBOL_GPL(memalloc_socks);
    
    /**
     * sk_set_memalloc - sets %SOCK_MEMALLOC
     * @sk: socket to set it on
     *
     * Set %SOCK_MEMALLOC on a socket for access to emergency reserves.
     * It's the responsibility of the admin to adjust min_free_kbytes
     * to meet the requirements
     */
    void sk_set_memalloc(struct sock *sk)
    {
    	sock_set_flag(sk, SOCK_MEMALLOC);
    	sk->sk_allocation |= __GFP_MEMALLOC;
    	static_key_slow_inc(&memalloc_socks);
    }
    EXPORT_SYMBOL_GPL(sk_set_memalloc);
    
    void sk_clear_memalloc(struct sock *sk)
    {
    	sock_reset_flag(sk, SOCK_MEMALLOC);
    	sk->sk_allocation &= ~__GFP_MEMALLOC;
    	static_key_slow_dec(&memalloc_socks);
    
    	/*
    	 * SOCK_MEMALLOC is allowed to ignore rmem limits to ensure forward
    	 * progress of swapping. However, if SOCK_MEMALLOC is cleared while
    	 * it has rmem allocations there is a risk that the user of the
    	 * socket cannot make forward progress due to exceeding the rmem
    	 * limits. By rights, sk_clear_memalloc() should only be called
    	 * on sockets being torn down but warn and reset the accounting if
    	 * that assumption breaks.
    	 */
    	if (WARN_ON(sk->sk_forward_alloc))
    		sk_mem_reclaim(sk);
    }
    EXPORT_SYMBOL_GPL(sk_clear_memalloc);
    
    int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
    {
    	int ret;
    	unsigned long pflags = current->flags;
    
    	/* these should have been dropped before queueing */
    	BUG_ON(!sock_flag(sk, SOCK_MEMALLOC));
    
    	current->flags |= PF_MEMALLOC;
    	ret = sk->sk_backlog_rcv(sk, skb);
    	tsk_restore_flags(current, pflags, PF_MEMALLOC);
    
    	return ret;
    }
    EXPORT_SYMBOL(__sk_backlog_rcv);
    
    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++;
    			pr_info("%s: `%s' (pid %d) tries to set negative timeout\n",
    				__func__, 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);
    		pr_warn("process `%s' is using obsolete %s SO_BSDCOMPAT\n",
    			warncomm, name);
    		warned++;
    	}
    }
    
    #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
    
    static void sock_disable_timestamp(struct sock *sk, unsigned long flags)
    {
    	if (sk->sk_flags & flags) {
    		sk->sk_flags &= ~flags;
    		if (!(sk->sk_flags & SK_FLAGS_TIMESTAMP))
    			net_disable_timestamp();
    	}
    }
    
    
    int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
    {
    	int err;
    	int skb_len;
    	unsigned long flags;
    	struct sk_buff_head *list = &sk->sk_receive_queue;
    
    	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) {
    		atomic_inc(&sk->sk_drops);
    		trace_sock_rcvqueue_full(sk, skb);
    		return -ENOMEM;
    	}
    
    	err = sk_filter(sk, skb);
    	if (err)
    		return err;
    
    	if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
    		atomic_inc(&sk->sk_drops);
    		return -ENOBUFS;
    	}
    
    	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;
    
    	/* we escape from rcu protected region, make sure we dont leak
    	 * a norefcounted dst
    	 */
    	skb_dst_force(skb);
    
    	spin_lock_irqsave(&list->lock, flags);
    	skb->dropcount = atomic_read(&sk->sk_drops);
    	__skb_queue_tail(list, skb);
    	spin_unlock_irqrestore(&list->lock, flags);
    
    	if (!sock_flag(sk, SOCK_DEAD))
    		sk->sk_data_ready(sk);
    	return 0;
    }
    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 (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
    		atomic_inc(&sk->sk_drops);
    		goto discard_and_relse;
    	}
    	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 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
    		bh_unlock_sock(sk);
    		atomic_inc(&sk->sk_drops);
    		goto discard_and_relse;
    	}
    
    	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_dst_get(sk);
    
    	if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
    		sk_tx_queue_clear(sk);
    		RCU_INIT_POINTER(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_setbindtodevice(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 (!ns_capable(net->user_ns, 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;
    
    	index = 0;
    	if (devname[0] != '\0') {
    		struct net_device *dev;
    
    		rcu_read_lock();
    		dev = dev_get_by_name_rcu(net, devname);
    		if (dev)
    			index = dev->ifindex;
    		rcu_read_unlock();
    		ret = -ENODEV;
    		if (!dev)
    			goto out;
    	}
    
    	lock_sock(sk);
    	sk->sk_bound_dev_if = index;
    	sk_dst_reset(sk);
    	release_sock(sk);
    
    	ret = 0;
    
    out:
    #endif
    
    	return ret;
    }
    
    static int sock_getbindtodevice(struct sock *sk, char __user *optval,
    				int __user *optlen, int len)
    {
    	int ret = -ENOPROTOOPT;
    #ifdef CONFIG_NETDEVICES
    	struct net *net = sock_net(sk);
    	char devname[IFNAMSIZ];
    
    	if (sk->sk_bound_dev_if == 0) {
    		len = 0;
    		goto zero;
    	}
    
    	ret = -EINVAL;
    	if (len < IFNAMSIZ)
    		goto out;
    
    	ret = netdev_get_name(net, devname, sk->sk_bound_dev_if);
    	if (ret)
    		goto out;
    
    	len = strlen(devname) + 1;
    
    	ret = -EFAULT;
    	if (copy_to_user(optval, devname, len))
    		goto out;
    
    zero:
    	ret = -EFAULT;
    	if (put_user(len, optlen))
    		goto out;
    
    	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, unsigned 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_setbindtodevice(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 ? SK_CAN_REUSE : SK_NO_REUSE);
    		break;
    	case SO_REUSEPORT:
    		sk->sk_reuseport = valbool;
    		break;
    	case SO_TYPE:
    	case SO_PROTOCOL:
    	case SO_DOMAIN:
    	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
    		 */
    		val = min_t(u32, val, sysctl_wmem_max);
    set_sndbuf:
    		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
    		sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF);
    		/* 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
    		 */
    		val = min_t(u32, 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.
    		 */
    		sk->sk_rcvbuf = max_t(u32, val * 2, SOCK_MIN_RCVBUF);
    		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 &&
    		    sk->sk_type == SOCK_STREAM)
    			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_tx = valbool;
    		break;
    
    	case SO_PRIORITY:
    		if ((val >= 0 && val <= 6) ||
    		    ns_capable(sock_net(sk)->user_ns, 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;
    		}
    		if (val & SOF_TIMESTAMPING_OPT_ID &&
    		    !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)) {
    			if (sk->sk_protocol == IPPROTO_TCP) {
    				if (sk->sk_state != TCP_ESTABLISHED) {
    					ret = -EINVAL;
    					break;
    				}
    				sk->sk_tskey = tcp_sk(sk)->snd_una;
    			} else {
    				sk->sk_tskey = 0;
    			}
    		}
    		sk->sk_tsflags = val;
    		if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
    			sock_enable_timestamp(sk,
    					      SOCK_TIMESTAMPING_RX_SOFTWARE);
    		else
    			sock_disable_timestamp(sk,
    					       (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE));
    		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_LOCK_FILTER:
    		if (sock_flag(sk, SOCK_FILTER_LOCKED) && !valbool)
    			ret = -EPERM;
    		else
    			sock_valbool_flag(sk, SOCK_FILTER_LOCKED, valbool);
    		break;
    
    	case SO_PASSSEC:
    		if (valbool)
    			set_bit(SOCK_PASSSEC, &sock->flags);
    		else
    			clear_bit(SOCK_PASSSEC, &sock->flags);
    		break;
    	case SO_MARK:
    		if (!ns_capable(sock_net(sk)->user_ns, 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) */
    	case SO_RXQ_OVFL:
    		sock_valbool_flag(sk, SOCK_RXQ_OVFL, valbool);
    		break;
    
    	case SO_WIFI_STATUS:
    		sock_valbool_flag(sk, SOCK_WIFI_STATUS, valbool);
    		break;
    
    	case SO_PEEK_OFF:
    		if (sock->ops->set_peek_off)
    			ret = sock->ops->set_peek_off(sk, val);
    		else
    			ret = -EOPNOTSUPP;
    		break;
    
    	case SO_NOFCS:
    		sock_valbool_flag(sk, SOCK_NOFCS, valbool);
    		break;
    
    	case SO_SELECT_ERR_QUEUE:
    		sock_valbool_flag(sk, SOCK_SELECT_ERR_QUEUE, valbool);
    		break;
    
    #ifdef CONFIG_NET_RX_BUSY_POLL
    	case SO_BUSY_POLL:
    		/* allow unprivileged users to decrease the value */
    		if ((val > sk->sk_ll_usec) && !capable(CAP_NET_ADMIN))
    			ret = -EPERM;
    		else {
    			if (val < 0)
    				ret = -EINVAL;
    			else
    				sk->sk_ll_usec = val;
    		}
    		break;
    #endif
    
    	case SO_MAX_PACING_RATE:
    		sk->sk_max_pacing_rate = val;
    		sk->sk_pacing_rate = min(sk->sk_pacing_rate,
    					 sk->sk_max_pacing_rate);
    		break;
    
    	default:
    		ret = -ENOPROTOOPT;
    		break;
    	}
    	release_sock(sk);
    	return ret;
    }
    EXPORT_SYMBOL(sock_setsockopt);
    
    
    static void cred_to_ucred(struct pid *pid, const struct cred *cred,
    			  struct ucred *ucred)
    {
    	ucred->pid = pid_vnr(pid);
    	ucred->uid = ucred->gid = -1;
    	if (cred) {
    		struct user_namespace *current_ns = current_user_ns();
    
    		ucred->uid = from_kuid_munged(current_ns, cred->euid);
    		ucred->gid = from_kgid_munged(current_ns, cred->egid);
    	}
    }
    
    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;
    
    	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_REUSEPORT:
    		v.val = sk->sk_reuseport;
    		break;
    
    	case SO_KEEPALIVE:
    		v.val = sock_flag(sk, SOCK_KEEPOPEN);
    		break;
    
    	case SO_TYPE:
    		v.val = sk->sk_type;
    		break;
    
    	case SO_PROTOCOL:
    		v.val = sk->sk_protocol;
    		break;
    
    	case SO_DOMAIN:
    		v.val = sk->sk_family;
    		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_tx;
    		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 = sk->sk_tsflags;
    		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);
    		break;
    
    	case SO_PEERCRED:
    	{
    		struct ucred peercred;
    		if (len > sizeof(peercred))
    			len = sizeof(peercred);
    		cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred);
    		if (copy_to_user(optval, &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);
    		break;
    
    	case SO_PEERSEC:
    		return security_socket_getpeersec_stream(sock, optval, optlen, len);
    
    	case SO_MARK:
    		v.val = sk->sk_mark;
    		break;
    
    	case SO_RXQ_OVFL:
    		v.val = sock_flag(sk, SOCK_RXQ_OVFL);
    		break;
    
    	case SO_WIFI_STATUS:
    		v.val = sock_flag(sk, SOCK_WIFI_STATUS);
    		break;
    
    	case SO_PEEK_OFF:
    		if (!sock->ops->set_peek_off)
    			return -EOPNOTSUPP;
    
    		v.val = sk->sk_peek_off;
    		break;
    	case SO_NOFCS:
    		v.val = sock_flag(sk, SOCK_NOFCS);
    		break;
    
    	case SO_BINDTODEVICE:
    		return sock_getbindtodevice(sk, optval, optlen, len);
    
    	case SO_GET_FILTER:
    		len = sk_get_filter(sk, (struct sock_filter __user *)optval, len);
    		if (len < 0)
    			return len;
    
    		goto lenout;
    
    	case SO_LOCK_FILTER:
    		v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
    		break;
    
    	case SO_BPF_EXTENSIONS:
    		v.val = bpf_tell_extensions();
    		break;
    
    	case SO_SELECT_ERR_QUEUE:
    		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
    		break;
    
    #ifdef CONFIG_NET_RX_BUSY_POLL
    	case SO_BUSY_POLL:
    		v.val = sk->sk_ll_usec;
    		break;
    #endif
    
    	case SO_MAX_PACING_RATE:
    		v.val = sk->sk_max_pacing_rate;
    		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);
    }
    
    /*
     * Copy all fields from osk to nsk but nsk->sk_refcnt must not change yet,
     * even temporarly, because of RCU lookups. sk_node should also be left as is.
     * We must not copy fields between sk_dontcopy_begin and sk_dontcopy_end
     */
    static void sock_copy(struct sock *nsk, const struct sock *osk)
    {
    #ifdef CONFIG_SECURITY_NETWORK
    	void *sptr = nsk->sk_security;
    #endif
    	memcpy(nsk, osk, offsetof(struct sock, sk_dontcopy_begin));
    
    	memcpy(&nsk->sk_dontcopy_end, &osk->sk_dontcopy_end,
    	       osk->sk_prot->obj_size - offsetof(struct sock, sk_dontcopy_end));
    
    #ifdef CONFIG_SECURITY_NETWORK
    	nsk->sk_security = sptr;
    	security_sk_clone(osk, nsk);
    #endif
    }
    
    void sk_prot_clear_portaddr_nulls(struct sock *sk, int size)
    {
    	unsigned long nulls1, nulls2;
    
    	nulls1 = offsetof(struct sock, __sk_common.skc_node.next);
    	nulls2 = offsetof(struct sock, __sk_common.skc_portaddr_node.next);
    	if (nulls1 > nulls2)
    		swap(nulls1, nulls2);
    
    	if (nulls1 != 0)
    		memset((char *)sk, 0, nulls1);
    	memset((char *)sk + nulls1 + sizeof(void *), 0,
    	       nulls2 - nulls1 - sizeof(void *));
    	memset((char *)sk + nulls2 + sizeof(void *), 0,
    	       size - nulls2 - sizeof(void *));
    }
    EXPORT_SYMBOL(sk_prot_clear_portaddr_nulls);
    
    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 & ~__GFP_ZERO);
    		if (!sk)
    			return sk;
    		if (priority & __GFP_ZERO) {
    			if (prot->clear_sk)
    				prot->clear_sk(sk, prot->obj_size);
    			else
    				sk_prot_clear_nulls(sk, prot->obj_size);
    		}
    	} else
    		sk = kmalloc(prot->obj_size, priority);
    
    	if (sk != NULL) {
    		kmemcheck_annotate_bitfield(sk, flags);
    
    		if (security_sk_alloc(sk, family, priority))
    			goto out_free;
    
    		if (!try_module_get(prot->owner))
    			goto out_free_sec;
    		sk_tx_queue_clear(sk);
    	}
    
    	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);
    }
    
    #if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
    void sock_update_netprioidx(struct sock *sk)
    {
    	if (in_interrupt())
    		return;
    
    	sk->sk_cgrp_prioidx = task_netprioidx(current);
    }
    EXPORT_SYMBOL_GPL(sock_update_netprioidx);
    #endif
    
    /**
     *	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));
    		atomic_set(&sk->sk_wmem_alloc, 1);
    
    		sock_update_classid(sk);
    		sock_update_netprioidx(sk);
    	}
    
    	return sk;
    }
    EXPORT_SYMBOL(sk_alloc);
    
    static void __sk_free(struct sock *sk)
    {
    	struct sk_filter *filter;
    
    	if (sk->sk_destruct)
    		sk->sk_destruct(sk);
    
    	filter = rcu_dereference_check(sk->sk_filter,
    				       atomic_read(&sk->sk_wmem_alloc) == 0);
    	if (filter) {
    		sk_filter_uncharge(sk, filter);
    		RCU_INIT_POINTER(sk->sk_filter, NULL);
    	}
    
    	sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP);
    
    	if (atomic_read(&sk->sk_omem_alloc))
    		pr_debug("%s: optmem leakage (%d bytes) detected\n",
    			 __func__, atomic_read(&sk->sk_omem_alloc));
    
    	if (sk->sk_peer_cred)
    		put_cred(sk->sk_peer_cred);
    	put_pid(sk->sk_peer_pid);
    	put_net(sock_net(sk));
    	sk_prot_free(sk->sk_prot_creator, sk);
    }
    
    void sk_free(struct sock *sk)
    {
    	/*
    	 * We subtract one from sk_wmem_alloc and can know if
    	 * some packets are still in some tx queue.
    	 * If not null, sock_wfree() will call __sk_free(sk) later
    	 */
    	if (atomic_dec_and_test(&sk->sk_wmem_alloc))
    		__sk_free(sk);
    }
    EXPORT_SYMBOL(sk_free);
    
    /*
     * Last sock_put should drop reference to sk->sk_net. It has already
     * been dropped in sk_change_net. Taking reference to stopping namespace
     * is not an option.
     * Take reference 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);
    
    static void sk_update_clone(const struct sock *sk, struct sock *newsk)
    {
    	if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
    		sock_update_memcg(newsk);
    }
    
    /**
     *	sk_clone_lock - clone a socket, and lock its clone
     *	@sk: the socket to clone
     *	@priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
     *
     *	Caller must unlock socket even in error path (bh_unlock_sock(newsk))
     */
    struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
    {
    	struct sock *newsk;
    	bool is_charged = true;
    
    	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;
    		newsk->sk_backlog.len = 0;
    
    		atomic_set(&newsk->sk_rmem_alloc, 0);
    		/*
    		 * sk_wmem_alloc set to one (see sk_free() and sock_wfree())
    		 */
    		atomic_set(&newsk->sk_wmem_alloc, 1);
    		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
    
    		spin_lock_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 = rcu_dereference_protected(newsk->sk_filter, 1);
    		if (filter != NULL)
    			/* though it's an empty new sock, the charging may fail
    			 * if sysctl_optmem_max was changed between creation of
    			 * original socket and cloning
    			 */
    			is_charged = sk_filter_charge(newsk, filter);
    
    		if (unlikely(!is_charged || xfrm_sk_clone_policy(newsk))) {
    			/* It is still raw copy of parent, so invalidate
    			 * destructor and make plain sk_free() */
    			newsk->sk_destruct = NULL;
    			bh_unlock_sock(newsk);
    			sk_free(newsk);
    			newsk = NULL;
    			goto out;
    		}
    
    		newsk->sk_err	   = 0;
    		newsk->sk_priority = 0;
    		/*
    		 * Before updating sk_refcnt, we must commit prior changes to memory
    		 * (Documentation/RCU/rculist_nulls.txt for details)
    		 */
    		smp_wmb();
    		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_wq = NULL;
    
    		sk_update_clone(sk, newsk);
    
    		if (newsk->sk_prot->sockets_allocated)
    			sk_sockets_allocated_inc(newsk);
    
    		if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
    			net_enable_timestamp();
    	}
    out:
    	return newsk;
    }
    EXPORT_SYMBOL_GPL(sk_clone_lock);
    
    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;
    	sk->sk_route_caps &= ~sk->sk_route_nocaps;
    	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;
    			sk->sk_gso_max_segs = dst->dev->gso_max_segs;
    		}
    	}
    }
    EXPORT_SYMBOL_GPL(sk_setup_caps);
    
    /*
     *	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;
    	unsigned int len = skb->truesize;
    
    	if (!sock_flag(sk, SOCK_USE_WRITE_QUEUE)) {
    		/*
    		 * Keep a reference on sk_wmem_alloc, this will be released
    		 * after sk_write_space() call
    		 */
    		atomic_sub(len - 1, &sk->sk_wmem_alloc);
    		sk->sk_write_space(sk);
    		len = 1;
    	}
    	/*
    	 * if sk_wmem_alloc reaches 0, we must finish what sk_free()
    	 * could not do because of in-flight packets
    	 */
    	if (atomic_sub_and_test(len, &sk->sk_wmem_alloc))
    		__sk_free(sk);
    }
    EXPORT_SYMBOL(sock_wfree);
    
    void skb_orphan_partial(struct sk_buff *skb)
    {
    	/* TCP stack sets skb->ooo_okay based on sk_wmem_alloc,
    	 * so we do not completely orphan skb, but transfert all
    	 * accounted bytes but one, to avoid unexpected reorders.
    	 */
    	if (skb->destructor == sock_wfree
    #ifdef CONFIG_INET
    	    || skb->destructor == tcp_wfree
    #endif
    		) {
    		atomic_sub(skb->truesize - 1, &skb->sk->sk_wmem_alloc);
    		skb->truesize = 1;
    	} else {
    		skb_orphan(skb);
    	}
    }
    EXPORT_SYMBOL(skb_orphan_partial);
    
    /*
     * Read buffer destructor automatically called from kfree_skb.
     */
    void sock_rfree(struct sk_buff *skb)
    {
    	struct sock *sk = skb->sk;
    	unsigned int len = skb->truesize;
    
    	atomic_sub(len, &sk->sk_rmem_alloc);
    	sk_mem_uncharge(sk, len);
    }
    EXPORT_SYMBOL(sock_rfree);
    
    void sock_edemux(struct sk_buff *skb)
    {
    	struct sock *sk = skb->sk;
    
    #ifdef CONFIG_INET
    	if (sk->sk_state == TCP_TIME_WAIT)
    		inet_twsk_put(inet_twsk(sk));
    	else
    #endif
    		sock_put(sk);
    }
    EXPORT_SYMBOL(sock_edemux);
    
    kuid_t sock_i_uid(struct sock *sk)
    {
    	kuid_t uid;
    
    	read_lock_bh(&sk->sk_callback_lock);
    	uid = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_uid : GLOBAL_ROOT_UID;
    	read_unlock_bh(&sk->sk_callback_lock);
    	return uid;
    }
    EXPORT_SYMBOL(sock_i_uid);
    
    unsigned long sock_i_ino(struct sock *sk)
    {
    	unsigned long ino;
    
    	read_lock_bh(&sk->sk_callback_lock);
    	ino = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_ino : 0;
    	read_unlock_bh(&sk->sk_callback_lock);
    	return ino;
    }
    EXPORT_SYMBOL(sock_i_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;
    }
    EXPORT_SYMBOL(sock_wmalloc);
    
    /*
     * Allocate a memory block from the socket's option memory buffer.
     */
    void *sock_kmalloc(struct sock *sk, int size, gfp_t priority)
    {
    	if ((unsigned int)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;
    }
    EXPORT_SYMBOL(sock_kmalloc);
    
    /*
     * 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);
    }
    EXPORT_SYMBOL(sock_kfree_s);
    
    /* 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_sleep(sk), &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_sleep(sk), &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, int max_page_order)
    {
    	struct sk_buff *skb = NULL;
    	unsigned long chunk;
    	gfp_t gfp_mask;
    	long timeo;
    	int err;
    	int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
    	struct page *page;
    	int i;
    
    	err = -EMSGSIZE;
    	if (npages > MAX_SKB_FRAGS)
    		goto failure;
    
    	timeo = sock_sndtimeo(sk, noblock);
    	while (!skb) {
    		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) {
    			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);
    			continue;
    		}
    
    		err = -ENOBUFS;
    		gfp_mask = sk->sk_allocation;
    		if (gfp_mask & __GFP_WAIT)
    			gfp_mask |= __GFP_REPEAT;
    
    		skb = alloc_skb(header_len, gfp_mask);
    		if (!skb)
    			goto failure;
    
    		skb->truesize += data_len;
    
    		for (i = 0; npages > 0; i++) {
    			int order = max_page_order;
    
    			while (order) {
    				if (npages >= 1 << order) {
    					page = alloc_pages(sk->sk_allocation |
    							   __GFP_COMP |
    							   __GFP_NOWARN |
    							   __GFP_NORETRY,
    							   order);
    					if (page)
    						goto fill_page;
    					/* Do not retry other high order allocations */
    					order = 1;
    					max_page_order = 0;
    				}
    				order--;
    			}
    			page = alloc_page(sk->sk_allocation);
    			if (!page)
    				goto failure;
    fill_page:
    			chunk = min_t(unsigned long, data_len,
    				      PAGE_SIZE << order);
    			skb_fill_page_desc(skb, i, page, 0, chunk);
    			data_len -= chunk;
    			npages -= 1 << order;
    		}
    	}
    
    	skb_set_owner_w(skb, sk);
    	return skb;
    
    interrupted:
    	err = sock_intr_errno(timeo);
    failure:
    	kfree_skb(skb);
    	*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, 0);
    }
    EXPORT_SYMBOL(sock_alloc_send_skb);
    
    /* On 32bit arches, an skb frag is limited to 2^15 */
    #define SKB_FRAG_PAGE_ORDER	get_order(32768)
    
    /**
     * skb_page_frag_refill - check that a page_frag contains enough room
     * @sz: minimum size of the fragment we want to get
     * @pfrag: pointer to page_frag
     * @prio: priority for memory allocation
     *
     * Note: While this allocator tries to use high order pages, there is
     * no guarantee that allocations succeed. Therefore, @sz MUST be
     * less or equal than PAGE_SIZE.
     */
    bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp)
    {
    	if (pfrag->page) {
    		if (atomic_read(&pfrag->page->_count) == 1) {
    			pfrag->offset = 0;
    			return true;
    		}
    		if (pfrag->offset + sz <= pfrag->size)
    			return true;
    		put_page(pfrag->page);
    	}
    
    	pfrag->offset = 0;
    	if (SKB_FRAG_PAGE_ORDER) {
    		pfrag->page = alloc_pages(gfp | __GFP_COMP |
    					  __GFP_NOWARN | __GFP_NORETRY,
    					  SKB_FRAG_PAGE_ORDER);
    		if (likely(pfrag->page)) {
    			pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
    			return true;
    		}
    	}
    	pfrag->page = alloc_page(gfp);
    	if (likely(pfrag->page)) {
    		pfrag->size = PAGE_SIZE;
    		return true;
    	}
    	return false;
    }
    EXPORT_SYMBOL(skb_page_frag_refill);
    
    bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
    {
    	if (likely(skb_page_frag_refill(32U, pfrag, sk->sk_allocation)))
    		return true;
    
    	sk_enter_memory_pressure(sk);
    	sk_stream_moderate_sndbuf(sk);
    	return false;
    }
    EXPORT_SYMBOL(sk_page_frag_refill);
    
    static void __lock_sock(struct sock *sk)
    	__releases(&sk->sk_lock.slock)
    	__acquires(&sk->sk_lock.slock)
    {
    	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)
    	__releases(&sk->sk_lock.slock)
    	__acquires(&sk->sk_lock.slock)
    {
    	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;
    
    			prefetch(next);
    			WARN_ON_ONCE(skb_dst_is_noref(skb));
    			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);
    
    	/*
    	 * Doing the zeroing here guarantee we can not loop forever
    	 * while a wild producer attempts to flood us.
    	 */
    	sk->sk_backlog.len = 0;
    }
    
    /**
     * 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_sleep(sk), &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_sleep(sk), &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);
    	long allocated;
    	int parent_status = UNDER_LIMIT;
    
    	sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
    
    	allocated = sk_memory_allocated_add(sk, amt, &parent_status);
    
    	/* Under limit. */
    	if (parent_status == UNDER_LIMIT &&
    			allocated <= sk_prot_mem_limits(sk, 0)) {
    		sk_leave_memory_pressure(sk);
    		return 1;
    	}
    
    	/* Under pressure. (we or our parents) */
    	if ((parent_status > SOFT_LIMIT) ||
    			allocated > sk_prot_mem_limits(sk, 1))
    		sk_enter_memory_pressure(sk);
    
    	/* Over hard limit (we or our parents) */
    	if ((parent_status == OVER_LIMIT) ||
    			(allocated > sk_prot_mem_limits(sk, 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 (sk_has_memory_pressure(sk)) {
    		int alloc;
    
    		if (!sk_under_memory_pressure(sk))
    			return 1;
    		alloc = sk_sockets_allocated_read_positive(sk);
    		if (sk_prot_mem_limits(sk, 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;
    	}
    
    	trace_sock_exceed_buf_limit(sk, prot, allocated);
    
    	/* Alas. Undo changes. */
    	sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
    
    	sk_memory_allocated_sub(sk, amt);
    
    	return 0;
    }
    EXPORT_SYMBOL(__sk_mem_schedule);
    
    /**
     *	__sk_reclaim - reclaim memory_allocated
     *	@sk: socket
     */
    void __sk_mem_reclaim(struct sock *sk)
    {
    	sk_memory_allocated_sub(sk,
    				sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT);
    	sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
    
    	if (sk_under_memory_pressure(sk) &&
    	    (sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)))
    		sk_leave_memory_pressure(sk);
    }
    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;
    }
    EXPORT_SYMBOL(sock_no_bind);
    
    int sock_no_connect(struct socket *sock, struct sockaddr *saddr,
    		    int len, int flags)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_connect);
    
    int sock_no_socketpair(struct socket *sock1, struct socket *sock2)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_socketpair);
    
    int sock_no_accept(struct socket *sock, struct socket *newsock, int flags)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_accept);
    
    int sock_no_getname(struct socket *sock, struct sockaddr *saddr,
    		    int *len, int peer)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_getname);
    
    unsigned int sock_no_poll(struct file *file, struct socket *sock, poll_table *pt)
    {
    	return 0;
    }
    EXPORT_SYMBOL(sock_no_poll);
    
    int sock_no_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_ioctl);
    
    int sock_no_listen(struct socket *sock, int backlog)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_listen);
    
    int sock_no_shutdown(struct socket *sock, int how)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_shutdown);
    
    int sock_no_setsockopt(struct socket *sock, int level, int optname,
    		    char __user *optval, unsigned int optlen)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_setsockopt);
    
    int sock_no_getsockopt(struct socket *sock, int level, int optname,
    		    char __user *optval, int __user *optlen)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_getsockopt);
    
    int sock_no_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
    		    size_t len)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_sendmsg);
    
    int sock_no_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
    		    size_t len, int flags)
    {
    	return -EOPNOTSUPP;
    }
    EXPORT_SYMBOL(sock_no_recvmsg);
    
    int sock_no_mmap(struct file *file, struct socket *sock, struct vm_area_struct *vma)
    {
    	/* Mirror missing mmap method error code */
    	return -ENODEV;
    }
    EXPORT_SYMBOL(sock_no_mmap);
    
    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;
    }
    EXPORT_SYMBOL(sock_no_sendpage);
    
    /*
     *	Default Socket Callbacks
     */
    
    static void sock_def_wakeup(struct sock *sk)
    {
    	struct socket_wq *wq;
    
    	rcu_read_lock();
    	wq = rcu_dereference(sk->sk_wq);
    	if (wq_has_sleeper(wq))
    		wake_up_interruptible_all(&wq->wait);
    	rcu_read_unlock();
    }
    
    static void sock_def_error_report(struct sock *sk)
    {
    	struct socket_wq *wq;
    
    	rcu_read_lock();
    	wq = rcu_dereference(sk->sk_wq);
    	if (wq_has_sleeper(wq))
    		wake_up_interruptible_poll(&wq->wait, POLLERR);
    	sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
    	rcu_read_unlock();
    }
    
    static void sock_def_readable(struct sock *sk)
    {
    	struct socket_wq *wq;
    
    	rcu_read_lock();
    	wq = rcu_dereference(sk->sk_wq);
    	if (wq_has_sleeper(wq))
    		wake_up_interruptible_sync_poll(&wq->wait, POLLIN | POLLPRI |
    						POLLRDNORM | POLLRDBAND);
    	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
    	rcu_read_unlock();
    }
    
    static void sock_def_write_space(struct sock *sk)
    {
    	struct socket_wq *wq;
    
    	rcu_read_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) {
    		wq = rcu_dereference(sk->sk_wq);
    		if (wq_has_sleeper(wq))
    			wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
    						POLLWRNORM | POLLWRBAND);
    
    		/* Should agree with poll, otherwise some programs break */
    		if (sock_writeable(sk))
    			sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
    	}
    
    	rcu_read_unlock();
    }
    
    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);
    }
    EXPORT_SYMBOL(sk_send_sigurg);
    
    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 (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_wq	=	sock->wq;
    		sock->sk	=	sk;
    	} else
    		sk->sk_wq	=	NULL;
    
    	spin_lock_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_frag.page	=	NULL;
    	sk->sk_frag.offset	=	0;
    	sk->sk_peek_off		=	-1;
    
    	sk->sk_peer_pid 	=	NULL;
    	sk->sk_peer_cred	=	NULL;
    	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);
    
    #ifdef CONFIG_NET_RX_BUSY_POLL
    	sk->sk_napi_id		=	0;
    	sk->sk_ll_usec		=	sysctl_net_busy_read;
    #endif
    
    	sk->sk_max_pacing_rate = ~0U;
    	sk->sk_pacing_rate = ~0U;
    	/*
    	 * Before updating sk_refcnt, we must commit prior changes to memory
    	 * (Documentation/RCU/rculist_nulls.txt for details)
    	 */
    	smp_wmb();
    	atomic_set(&sk->sk_refcnt, 1);
    	atomic_set(&sk->sk_drops, 0);
    }
    EXPORT_SYMBOL(sock_init_data);
    
    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);
    
    	/* Warning : release_cb() might need to release sk ownership,
    	 * ie call sock_release_ownership(sk) before us.
    	 */
    	if (sk->sk_prot->release_cb)
    		sk->sk_prot->release_cb(sk);
    
    	sock_release_ownership(sk);
    	if (waitqueue_active(&sk->sk_lock.wq))
    		wake_up(&sk->sk_lock.wq);
    	spin_unlock_bh(&sk->sk_lock.slock);
    }
    EXPORT_SYMBOL(release_sock);
    
    /**
     * lock_sock_fast - fast version of lock_sock
     * @sk: socket
     *
     * This version should be used for very small section, where process wont block
     * return false if fast path is taken
     *   sk_lock.slock locked, owned = 0, BH disabled
     * return true if slow path is taken
     *   sk_lock.slock unlocked, owned = 1, BH enabled
     */
    bool lock_sock_fast(struct sock *sk)
    {
    	might_sleep();
    	spin_lock_bh(&sk->sk_lock.slock);
    
    	if (!sk->sk_lock.owned)
    		/*
    		 * Note : We must disable BH
    		 */
    		return false;
    
    	__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, 0, 0, _RET_IP_);
    	local_bh_enable();
    	return true;
    }
    EXPORT_SYMBOL(lock_sock_fast);
    
    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)) {
    		unsigned long previous_flags = sk->sk_flags;
    
    		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 (!(previous_flags & SK_FLAGS_TIMESTAMP))
    			net_enable_timestamp();
    	}
    }
    
    int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len,
    		       int level, int type)
    {
    	struct sock_exterr_skb *serr;
    	struct sk_buff *skb, *skb2;
    	int copied, err;
    
    	err = -EAGAIN;
    	skb = skb_dequeue(&sk->sk_error_queue);
    	if (skb == NULL)
    		goto out;
    
    	copied = skb->len;
    	if (copied > len) {
    		msg->msg_flags |= MSG_TRUNC;
    		copied = len;
    	}
    	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
    	if (err)
    		goto out_free_skb;
    
    	sock_recv_timestamp(msg, sk, skb);
    
    	serr = SKB_EXT_ERR(skb);
    	put_cmsg(msg, level, type, sizeof(serr->ee), &serr->ee);
    
    	msg->msg_flags |= MSG_ERRQUEUE;
    	err = copied;
    
    	/* Reset and regenerate socket error */
    	spin_lock_bh(&sk->sk_error_queue.lock);
    	sk->sk_err = 0;
    	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
    		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
    		spin_unlock_bh(&sk->sk_error_queue.lock);
    		sk->sk_error_report(sk);
    	} else
    		spin_unlock_bh(&sk->sk_error_queue.lock);
    
    out_free_skb:
    	kfree_skb(skb);
    out:
    	return err;
    }
    EXPORT_SYMBOL(sock_recv_errqueue);
    
    /*
     *	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, unsigned 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, unsigned 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);
    
    	if (sk->sk_frag.page) {
    		put_page(sk->sk_frag.page);
    		sk->sk_frag.page = NULL;
    	}
    
    	sock_put(sk);
    }
    EXPORT_SYMBOL(sk_common_release);
    
    #ifdef CONFIG_PROC_FS
    #define PROTO_INUSE_NR	64	/* should be enough for the first time */
    struct prot_inuse {
    	int val[PROTO_INUSE_NR];
    };
    
    static DECLARE_BITMAP(proto_inuse_idx, PROTO_INUSE_NR);
    
    #ifdef CONFIG_NET_NS
    void sock_prot_inuse_add(struct net *net, struct proto *prot, int val)
    {
    	__this_cpu_add(net->core.inuse->val[prot->inuse_idx], val);
    }
    EXPORT_SYMBOL_GPL(sock_prot_inuse_add);
    
    int sock_prot_inuse_get(struct net *net, struct proto *prot)
    {
    	int cpu, idx = prot->inuse_idx;
    	int res = 0;
    
    	for_each_possible_cpu(cpu)
    		res += per_cpu_ptr(net->core.inuse, cpu)->val[idx];
    
    	return res >= 0 ? res : 0;
    }
    EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
    
    static int __net_init sock_inuse_init_net(struct net *net)
    {
    	net->core.inuse = alloc_percpu(struct prot_inuse);
    	return net->core.inuse ? 0 : -ENOMEM;
    }
    
    static void __net_exit sock_inuse_exit_net(struct net *net)
    {
    	free_percpu(net->core.inuse);
    }
    
    static struct pernet_operations net_inuse_ops = {
    	.init = sock_inuse_init_net,
    	.exit = sock_inuse_exit_net,
    };
    
    static __init int net_inuse_init(void)
    {
    	if (register_pernet_subsys(&net_inuse_ops))
    		panic("Cannot initialize net inuse counters");
    
    	return 0;
    }
    
    core_initcall(net_inuse_init);
    #else
    static DEFINE_PER_CPU(struct prot_inuse, prot_inuse);
    
    void sock_prot_inuse_add(struct net *net, struct proto *prot, int val)
    {
    	__this_cpu_add(prot_inuse.val[prot->inuse_idx], val);
    }
    EXPORT_SYMBOL_GPL(sock_prot_inuse_add);
    
    int sock_prot_inuse_get(struct net *net, struct proto *prot)
    {
    	int cpu, idx = prot->inuse_idx;
    	int res = 0;
    
    	for_each_possible_cpu(cpu)
    		res += per_cpu(prot_inuse, cpu).val[idx];
    
    	return res >= 0 ? res : 0;
    }
    EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
    #endif
    
    static void assign_proto_idx(struct proto *prot)
    {
    	prot->inuse_idx = find_first_zero_bit(proto_inuse_idx, PROTO_INUSE_NR);
    
    	if (unlikely(prot->inuse_idx == PROTO_INUSE_NR - 1)) {
    		pr_err("PROTO_INUSE_NR exhausted\n");
    		return;
    	}
    
    	set_bit(prot->inuse_idx, proto_inuse_idx);
    }
    
    static void release_proto_idx(struct proto *prot)
    {
    	if (prot->inuse_idx != PROTO_INUSE_NR - 1)
    		clear_bit(prot->inuse_idx, proto_inuse_idx);
    }
    #else
    static inline void assign_proto_idx(struct proto *prot)
    {
    }
    
    static inline void release_proto_idx(struct proto *prot)
    {
    }
    #endif
    
    int proto_register(struct proto *prot, int alloc_slab)
    {
    	if (alloc_slab) {
    		prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
    					SLAB_HWCACHE_ALIGN | prot->slab_flags,
    					NULL);
    
    		if (prot->slab == NULL) {
    			pr_crit("%s: Can't create sock SLAB cache!\n",
    				prot->name);
    			goto out;
    		}
    
    		if (prot->rsk_prot != NULL) {
    			prot->rsk_prot->slab_name = kasprintf(GFP_KERNEL, "request_sock_%s", prot->name);
    			if (prot->rsk_prot->slab_name == NULL)
    				goto out_free_sock_slab;
    
    			prot->rsk_prot->slab = kmem_cache_create(prot->rsk_prot->slab_name,
    								 prot->rsk_prot->obj_size, 0,
    								 SLAB_HWCACHE_ALIGN, NULL);
    
    			if (prot->rsk_prot->slab == NULL) {
    				pr_crit("%s: Can't create request sock SLAB cache!\n",
    					prot->name);
    				goto out_free_request_sock_slab_name;
    			}
    		}
    
    		if (prot->twsk_prot != NULL) {
    			prot->twsk_prot->twsk_slab_name = kasprintf(GFP_KERNEL, "tw_sock_%s", prot->name);
    
    			if (prot->twsk_prot->twsk_slab_name == NULL)
    				goto out_free_request_sock_slab;
    
    			prot->twsk_prot->twsk_slab =
    				kmem_cache_create(prot->twsk_prot->twsk_slab_name,
    						  prot->twsk_prot->twsk_obj_size,
    						  0,
    						  SLAB_HWCACHE_ALIGN |
    							prot->slab_flags,
    						  NULL);
    			if (prot->twsk_prot->twsk_slab == NULL)
    				goto out_free_timewait_sock_slab_name;
    		}
    	}
    
    	mutex_lock(&proto_list_mutex);
    	list_add(&prot->node, &proto_list);
    	assign_proto_idx(prot);
    	mutex_unlock(&proto_list_mutex);
    	return 0;
    
    out_free_timewait_sock_slab_name:
    	kfree(prot->twsk_prot->twsk_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:
    	if (prot->rsk_prot)
    		kfree(prot->rsk_prot->slab_name);
    out_free_sock_slab:
    	kmem_cache_destroy(prot->slab);
    	prot->slab = NULL;
    out:
    	return -ENOBUFS;
    }
    EXPORT_SYMBOL(proto_register);
    
    void proto_unregister(struct proto *prot)
    {
    	mutex_lock(&proto_list_mutex);
    	release_proto_idx(prot);
    	list_del(&prot->node);
    	mutex_unlock(&proto_list_mutex);
    
    	if (prot->slab != NULL) {
    		kmem_cache_destroy(prot->slab);
    		prot->slab = NULL;
    	}
    
    	if (prot->rsk_prot != NULL && prot->rsk_prot->slab != NULL) {
    		kmem_cache_destroy(prot->rsk_prot->slab);
    		kfree(prot->rsk_prot->slab_name);
    		prot->rsk_prot->slab = NULL;
    	}
    
    	if (prot->twsk_prot != NULL && prot->twsk_prot->twsk_slab != NULL) {
    		kmem_cache_destroy(prot->twsk_prot->twsk_slab);
    		kfree(prot->twsk_prot->twsk_slab_name);
    		prot->twsk_prot->twsk_slab = NULL;
    	}
    }
    EXPORT_SYMBOL(proto_unregister);
    
    #ifdef CONFIG_PROC_FS
    static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
    	__acquires(proto_list_mutex)
    {
    	mutex_lock(&proto_list_mutex);
    	return seq_list_start_head(&proto_list, *pos);
    }
    
    static void *proto_seq_next(struct seq_file *seq, void *v, loff_t *pos)
    {
    	return seq_list_next(v, &proto_list, pos);
    }
    
    static void proto_seq_stop(struct seq_file *seq, void *v)
    	__releases(proto_list_mutex)
    {
    	mutex_unlock(&proto_list_mutex);
    }
    
    static char proto_method_implemented(const void *method)
    {
    	return method == NULL ? 'n' : 'y';
    }
    static long sock_prot_memory_allocated(struct proto *proto)
    {
    	return proto->memory_allocated != NULL ? proto_memory_allocated(proto) : -1L;
    }
    
    static char *sock_prot_memory_pressure(struct proto *proto)
    {
    	return proto->memory_pressure != NULL ?
    	proto_memory_pressure(proto) ? "yes" : "no" : "NI";
    }
    
    static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
    {
    
    	seq_printf(seq, "%-9s %4u %6d  %6ld   %-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,
    		   sock_prot_inuse_get(seq_file_net(seq), proto),
    		   sock_prot_memory_allocated(proto),
    		   sock_prot_memory_pressure(proto),
    		   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 == &proto_list)
    		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, list_entry(v, struct proto, node));
    	return 0;
    }
    
    static const 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_net(inode, file, &proto_seq_ops,
    			    sizeof(struct seq_net_private));
    }
    
    static const struct file_operations proto_seq_fops = {
    	.owner		= THIS_MODULE,
    	.open		= proto_seq_open,
    	.read		= seq_read,
    	.llseek		= seq_lseek,
    	.release	= seq_release_net,
    };
    
    static __net_init int proto_init_net(struct net *net)
    {
    	if (!proc_create("protocols", S_IRUGO, net->proc_net, &proto_seq_fops))
    		return -ENOMEM;
    
    	return 0;
    }
    
    static __net_exit void proto_exit_net(struct net *net)
    {
    	remove_proc_entry("protocols", net->proc_net);
    }
    
    
    static __net_initdata struct pernet_operations proto_net_ops = {
    	.init = proto_init_net,
    	.exit = proto_exit_net,
    };
    
    static int __init proto_init(void)
    {
    	return register_pernet_subsys(&proto_net_ops);
    }
    
    subsys_initcall(proto_init);
    
    #endif /* PROC_FS */