// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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:
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <asm/unaligned.h>
#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/sched/mm.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 <linux/compat.h>

#include <linux/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/sock_diag.h>

#include <linux/filter.h>
#include <net/sock_reuseport.h>
#include <net/bpf_sk_storage.h>

#include <trace/events/sock.h>

#include <net/tcp.h>
#include <net/busy_poll.h>

#include <linux/ethtool.h>

#include "dev.h"

static DEFINE_MUTEX(proto_list_mutex);
static LIST_HEAD(proto_list);

static void sock_def_write_space_wfree(struct sock *sk);
static void sock_def_write_space(struct sock *sk);

/**
 * 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 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 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 socket 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);

/*
 * Each address family might have different locking rules, so we have
 * one slock key per address family and separate keys for internal and
 * userspace sockets.
 */
static struct lock_class_key af_family_keys[AF_MAX];
static struct lock_class_key af_family_kern_keys[AF_MAX];
static struct lock_class_key af_family_slock_keys[AF_MAX];
static struct lock_class_key af_family_kern_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):
 */

#define _sock_locks(x)                                            \
  x "AF_UNSPEC",        x "AF_UNIX"     ,       x "AF_INET"     , \
  x "AF_AX25"  ,        x "AF_IPX"      ,       x "AF_APPLETALK", \
  x "AF_NETROM",        x "AF_BRIDGE"   ,       x "AF_ATMPVC"   , \
  x "AF_X25"   ,        x "AF_INET6"    ,       x "AF_ROSE"     , \
  x "AF_DECnet",        x "AF_NETBEUI"  ,       x "AF_SECURITY" , \
  x "AF_KEY"   ,        x "AF_NETLINK"  ,       x "AF_PACKET"   , \
  x "AF_ASH"   ,        x "AF_ECONET"   ,       x "AF_ATMSVC"   , \
  x "AF_RDS"   ,        x "AF_SNA"      ,       x "AF_IRDA"     , \
  x "AF_PPPOX" ,        x "AF_WANPIPE"  ,       x "AF_LLC"      , \
  x "27"       ,        x "28"          ,       x "AF_CAN"      , \
  x "AF_TIPC"  ,        x "AF_BLUETOOTH",       x "IUCV"        , \
  x "AF_RXRPC" ,        x "AF_ISDN"     ,       x "AF_PHONET"   , \
  x "AF_IEEE802154",    x "AF_CAIF"     ,       x "AF_ALG"      , \
  x "AF_NFC"   ,        x "AF_VSOCK"    ,       x "AF_KCM"      , \
  x "AF_QIPCRTR",       x "AF_SMC"      ,       x "AF_XDP"      , \
  x "AF_MCTP"  , \
  x "AF_MAX"

static const char *const af_family_key_strings[AF_MAX+1] = {
        _sock_locks("sk_lock-")
};
static const char *const af_family_slock_key_strings[AF_MAX+1] = {
        _sock_locks("slock-")
};
static const char *const af_family_clock_key_strings[AF_MAX+1] = {
        _sock_locks("clock-")
};

static const char *const af_family_kern_key_strings[AF_MAX+1] = {
        _sock_locks("k-sk_lock-")
};
static const char *const af_family_kern_slock_key_strings[AF_MAX+1] = {
        _sock_locks("k-slock-")
};
static const char *const af_family_kern_clock_key_strings[AF_MAX+1] = {
        _sock_locks("k-clock-")
};
static const char *const af_family_rlock_key_strings[AF_MAX+1] = {
        _sock_locks("rlock-")
};
static const char *const af_family_wlock_key_strings[AF_MAX+1] = {
        _sock_locks("wlock-")
};
static const char *const af_family_elock_key_strings[AF_MAX+1] = {
        _sock_locks("elock-")
};

/*
 * sk_callback_lock and sk queues 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];
static struct lock_class_key af_rlock_keys[AF_MAX];
static struct lock_class_key af_wlock_keys[AF_MAX];
static struct lock_class_key af_elock_keys[AF_MAX];
static struct lock_class_key af_kern_callback_keys[AF_MAX];

/* 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);

int sysctl_tstamp_allow_data __read_mostly = 1;

DEFINE_STATIC_KEY_FALSE(memalloc_socks_key);
EXPORT_SYMBOL_GPL(memalloc_socks_key);

/**
 * 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_branch_inc(&memalloc_socks_key);
}
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_branch_dec(&memalloc_socks_key);

        /*
         * SOCK_MEMALLOC is allowed to ignore rmem limits to ensure forward
         * progress of swapping. SOCK_MEMALLOC may be cleared while
         * it has rmem allocations due to the last swapfile being deactivated
         * but there is a risk that the socket is unusable due to exceeding
         * the rmem limits. Reclaim the reserves and obey rmem limits again.
         */
        sk_mem_reclaim(sk);
}
EXPORT_SYMBOL_GPL(sk_clear_memalloc);

int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
        int ret;
        unsigned int noreclaim_flag;

        /* these should have been dropped before queueing */
        BUG_ON(!sock_flag(sk, SOCK_MEMALLOC));

        noreclaim_flag = memalloc_noreclaim_save();
        ret = INDIRECT_CALL_INET(sk->sk_backlog_rcv,
                                 tcp_v6_do_rcv,
                                 tcp_v4_do_rcv,
                                 sk, skb);
        memalloc_noreclaim_restore(noreclaim_flag);

        return ret;
}
EXPORT_SYMBOL(__sk_backlog_rcv);

void sk_error_report(struct sock *sk)
{
        sk->sk_error_report(sk);

        switch (sk->sk_family) {
        case AF_INET:
                fallthrough;
        case AF_INET6:
                trace_inet_sk_error_report(sk);
                break;
        default:
                break;
        }
}
EXPORT_SYMBOL(sk_error_report);

int sock_get_timeout(long timeo, void *optval, bool old_timeval)
{
        struct __kernel_sock_timeval tv;

        if (timeo == MAX_SCHEDULE_TIMEOUT) {
                tv.tv_sec = 0;
                tv.tv_usec = 0;
        } else {
                tv.tv_sec = timeo / HZ;
                tv.tv_usec = ((timeo % HZ) * USEC_PER_SEC) / HZ;
        }

        if (old_timeval && in_compat_syscall() && !COMPAT_USE_64BIT_TIME) {
                struct old_timeval32 tv32 = { tv.tv_sec, tv.tv_usec };
                *(struct old_timeval32 *)optval = tv32;
                return sizeof(tv32);
        }

        if (old_timeval) {
                struct __kernel_old_timeval old_tv;
                old_tv.tv_sec = tv.tv_sec;
                old_tv.tv_usec = tv.tv_usec;
                *(struct __kernel_old_timeval *)optval = old_tv;
                return sizeof(old_tv);
        }

        *(struct __kernel_sock_timeval *)optval = tv;
        return sizeof(tv);
}
EXPORT_SYMBOL(sock_get_timeout);

int sock_copy_user_timeval(struct __kernel_sock_timeval *tv,
                           sockptr_t optval, int optlen, bool old_timeval)
{
        if (old_timeval && in_compat_syscall() && !COMPAT_USE_64BIT_TIME) {
                struct old_timeval32 tv32;

                if (optlen < sizeof(tv32))
                        return -EINVAL;

                if (copy_from_sockptr(&tv32, optval, sizeof(tv32)))
                        return -EFAULT;
                tv->tv_sec = tv32.tv_sec;
                tv->tv_usec = tv32.tv_usec;
        } else if (old_timeval) {
                struct __kernel_old_timeval old_tv;

                if (optlen < sizeof(old_tv))
                        return -EINVAL;
                if (copy_from_sockptr(&old_tv, optval, sizeof(old_tv)))
                        return -EFAULT;
                tv->tv_sec = old_tv.tv_sec;
                tv->tv_usec = old_tv.tv_usec;
        } else {
                if (optlen < sizeof(*tv))
                        return -EINVAL;
                if (copy_from_sockptr(tv, optval, sizeof(*tv)))
                        return -EFAULT;
        }

        return 0;
}
EXPORT_SYMBOL(sock_copy_user_timeval);

static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
                            bool old_timeval)
{
        struct __kernel_sock_timeval tv;
        int err = sock_copy_user_timeval(&tv, optval, optlen, old_timeval);

        if (err)
                return err;

        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 + DIV_ROUND_UP((unsigned long)tv.tv_usec, USEC_PER_SEC / HZ);
        return 0;
}

static bool sock_needs_netstamp(const struct sock *sk)
{
        switch (sk->sk_family) {
        case AF_UNSPEC:
        case AF_UNIX:
                return false;
        default:
                return true;
        }
}

static void sock_disable_timestamp(struct sock *sk, unsigned long flags)
{
        if (sk->sk_flags & flags) {
                sk->sk_flags &= ~flags;
                if (sock_needs_netstamp(sk) &&
                    !(sk->sk_flags & SK_FLAGS_TIMESTAMP))
                        net_disable_timestamp();
        }
}


int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        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;
        }

        if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
                atomic_inc(&sk->sk_drops);
                return -ENOBUFS;
        }

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

        /* we escape from rcu protected region, make sure we dont leak
         * a norefcounted dst
         */
        skb_dst_force(skb);

        spin_lock_irqsave(&list->lock, flags);
        sock_skb_set_dropcount(sk, skb);
        __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 sock_queue_rcv_skb_reason(struct sock *sk, struct sk_buff *skb,
                              enum skb_drop_reason *reason)
{
        enum skb_drop_reason drop_reason;
        int err;

        err = sk_filter(sk, skb);
        if (err) {
                drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
                goto out;
        }
        err = __sock_queue_rcv_skb(sk, skb);
        switch (err) {
        case -ENOMEM:
                drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
                break;
        case -ENOBUFS:
                drop_reason = SKB_DROP_REASON_PROTO_MEM;
                break;
        default:
                drop_reason = SKB_NOT_DROPPED_YET;
                break;
        }
out:
        if (reason)
                *reason = drop_reason;
        return err;
}
EXPORT_SYMBOL(sock_queue_rcv_skb_reason);

int __sk_receive_skb(struct sock *sk, struct sk_buff *skb,
                     const int nested, unsigned int trim_cap, bool refcounted)
{
        int rc = NET_RX_SUCCESS;

        if (sk_filter_trim_cap(sk, skb, trim_cap))
                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, _RET_IP_);
        } else if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) {
                bh_unlock_sock(sk);
                atomic_inc(&sk->sk_drops);
                goto discard_and_relse;
        }

        bh_unlock_sock(sk);
out:
        if (refcounted)
                sock_put(sk);
        return rc;
discard_and_relse:
        kfree_skb(skb);
        goto out;
}
EXPORT_SYMBOL(__sk_receive_skb);

INDIRECT_CALLABLE_DECLARE(struct dst_entry *ip6_dst_check(struct dst_entry *,
                                                          u32));
INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
                                                           u32));
struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie)
{
        struct dst_entry *dst = __sk_dst_get(sk);

        if (dst && dst->obsolete &&
            INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check, ipv4_dst_check,
                               dst, cookie) == NULL) {
                sk_tx_queue_clear(sk);
                sk->sk_dst_pending_confirm = 0;
                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 &&
            INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check, ipv4_dst_check,
                               dst, cookie) == NULL) {
                sk_dst_reset(sk);
                dst_release(dst);
                return NULL;
        }

        return dst;
}
EXPORT_SYMBOL(sk_dst_check);

static int sock_bindtoindex_locked(struct sock *sk, int ifindex)
{
        int ret = -ENOPROTOOPT;
#ifdef CONFIG_NETDEVICES
        struct net *net = sock_net(sk);

        /* Sorry... */
        ret = -EPERM;
        if (sk->sk_bound_dev_if && !ns_capable(net->user_ns, CAP_NET_RAW))
                goto out;

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

        /* Paired with all READ_ONCE() done locklessly. */
        WRITE_ONCE(sk->sk_bound_dev_if, ifindex);

        if (sk->sk_prot->rehash)
                sk->sk_prot->rehash(sk);
        sk_dst_reset(sk);

        ret = 0;

out:
#endif

        return ret;
}

int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk)
{
        int ret;

        if (lock_sk)
                lock_sock(sk);
        ret = sock_bindtoindex_locked(sk, ifindex);
        if (lock_sk)
                release_sock(sk);

        return ret;
}
EXPORT_SYMBOL(sock_bindtoindex);

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

        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_sockptr(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;
        }

        return sock_bindtoindex(sk, index, true);
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
        int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
        struct net *net = sock_net(sk);
        char devname[IFNAMSIZ];

        if (bound_dev_if == 0) {
                len = 0;
                goto zero;
        }

        ret = -EINVAL;
        if (len < IFNAMSIZ)
                goto out;

        ret = netdev_get_name(net, devname, 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;
}

bool sk_mc_loop(struct sock *sk)
{
        if (dev_recursion_level())
                return false;
        if (!sk)
                return true;
        switch (sk->sk_family) {
        case AF_INET:
                return inet_sk(sk)->mc_loop;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                return inet6_sk(sk)->mc_loop;
#endif
        }
        WARN_ON_ONCE(1);
        return true;
}
EXPORT_SYMBOL(sk_mc_loop);

void sock_set_reuseaddr(struct sock *sk)
{
        lock_sock(sk);
        sk->sk_reuse = SK_CAN_REUSE;
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_reuseaddr);

void sock_set_reuseport(struct sock *sk)
{
        lock_sock(sk);
        sk->sk_reuseport = true;
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_reuseport);

void sock_no_linger(struct sock *sk)
{
        lock_sock(sk);
        sk->sk_lingertime = 0;
        sock_set_flag(sk, SOCK_LINGER);
        release_sock(sk);
}
EXPORT_SYMBOL(sock_no_linger);

void sock_set_priority(struct sock *sk, u32 priority)
{
        lock_sock(sk);
        sk->sk_priority = priority;
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_priority);

void sock_set_sndtimeo(struct sock *sk, s64 secs)
{
        lock_sock(sk);
        if (secs && secs < MAX_SCHEDULE_TIMEOUT / HZ - 1)
                sk->sk_sndtimeo = secs * HZ;
        else
                sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_sndtimeo);

static void __sock_set_timestamps(struct sock *sk, bool val, bool new, bool ns)
{
        if (val)  {
                sock_valbool_flag(sk, SOCK_TSTAMP_NEW, new);
                sock_valbool_flag(sk, SOCK_RCVTSTAMPNS, ns);
                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);
        }
}

void sock_enable_timestamps(struct sock *sk)
{
        lock_sock(sk);
        __sock_set_timestamps(sk, true, false, true);
        release_sock(sk);
}
EXPORT_SYMBOL(sock_enable_timestamps);

void sock_set_timestamp(struct sock *sk, int optname, bool valbool)
{
        switch (optname) {
        case SO_TIMESTAMP_OLD:
                __sock_set_timestamps(sk, valbool, false, false);
                break;
        case SO_TIMESTAMP_NEW:
                __sock_set_timestamps(sk, valbool, true, false);
                break;
        case SO_TIMESTAMPNS_OLD:
                __sock_set_timestamps(sk, valbool, false, true);
                break;
        case SO_TIMESTAMPNS_NEW:
                __sock_set_timestamps(sk, valbool, true, true);
                break;
        }
}

static int sock_timestamping_bind_phc(struct sock *sk, int phc_index)
{
        struct net *net = sock_net(sk);
        struct net_device *dev = NULL;
        bool match = false;
        int *vclock_index;
        int i, num;

        if (sk->sk_bound_dev_if)
                dev = dev_get_by_index(net, sk->sk_bound_dev_if);

        if (!dev) {
                pr_err("%s: sock not bind to device\n", __func__);
                return -EOPNOTSUPP;
        }

        num = ethtool_get_phc_vclocks(dev, &vclock_index);
        dev_put(dev);

        for (i = 0; i < num; i++) {
                if (*(vclock_index + i) == phc_index) {
                        match = true;
                        break;
                }
        }

        if (num > 0)
                kfree(vclock_index);

        if (!match)
                return -EINVAL;

        sk->sk_bind_phc = phc_index;

        return 0;
}

int sock_set_timestamping(struct sock *sk, int optname,
                          struct so_timestamping timestamping)
{
        int val = timestamping.flags;
        int ret;

        if (val & ~SOF_TIMESTAMPING_MASK)
                return -EINVAL;

        if (val & SOF_TIMESTAMPING_OPT_ID &&
            !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)) {
                if (sk_is_tcp(sk)) {
                        if ((1 << sk->sk_state) &
                            (TCPF_CLOSE | TCPF_LISTEN))
                                return -EINVAL;
                        atomic_set(&sk->sk_tskey, tcp_sk(sk)->snd_una);
                } else {
                        atomic_set(&sk->sk_tskey, 0);
                }
        }

        if (val & SOF_TIMESTAMPING_OPT_STATS &&
            !(val & SOF_TIMESTAMPING_OPT_TSONLY))
                return -EINVAL;

        if (val & SOF_TIMESTAMPING_BIND_PHC) {
                ret = sock_timestamping_bind_phc(sk, timestamping.bind_phc);
                if (ret)
                        return ret;
        }

        sk->sk_tsflags = val;
        sock_valbool_flag(sk, SOCK_TSTAMP_NEW, optname == SO_TIMESTAMPING_NEW);

        if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
                sock_enable_timestamp(sk,
                                      SOCK_TIMESTAMPING_RX_SOFTWARE);
        else
                sock_disable_timestamp(sk,
                                       (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE));
        return 0;
}

void sock_set_keepalive(struct sock *sk)
{
        lock_sock(sk);
        if (sk->sk_prot->keepalive)
                sk->sk_prot->keepalive(sk, true);
        sock_valbool_flag(sk, SOCK_KEEPOPEN, true);
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_keepalive);

static void __sock_set_rcvbuf(struct sock *sk, int val)
{
        /* Ensure val * 2 fits into an int, to prevent max_t() from treating it
         * as a negative value.
         */
        val = min_t(int, val, INT_MAX / 2);
        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.
         */
        WRITE_ONCE(sk->sk_rcvbuf, max_t(int, val * 2, SOCK_MIN_RCVBUF));
}

void sock_set_rcvbuf(struct sock *sk, int val)
{
        lock_sock(sk);
        __sock_set_rcvbuf(sk, val);
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_rcvbuf);

static void __sock_set_mark(struct sock *sk, u32 val)
{
        if (val != sk->sk_mark) {
                sk->sk_mark = val;
                sk_dst_reset(sk);
        }
}

void sock_set_mark(struct sock *sk, u32 val)
{
        lock_sock(sk);
        __sock_set_mark(sk, val);
        release_sock(sk);
}
EXPORT_SYMBOL(sock_set_mark);

static void sock_release_reserved_memory(struct sock *sk, int bytes)
{
        /* Round down bytes to multiple of pages */
        bytes &= ~(SK_MEM_QUANTUM - 1);

        WARN_ON(bytes > sk->sk_reserved_mem);
        sk->sk_reserved_mem -= bytes;
        sk_mem_reclaim(sk);
}

static int sock_reserve_memory(struct sock *sk, int bytes)
{
        long allocated;
        bool charged;
        int pages;

        if (!mem_cgroup_sockets_enabled || !sk->sk_memcg || !sk_has_account(sk))
                return -EOPNOTSUPP;

        if (!bytes)
                return 0;

        pages = sk_mem_pages(bytes);

        /* pre-charge to memcg */
        charged = mem_cgroup_charge_skmem(sk->sk_memcg, pages,
                                          GFP_KERNEL | __GFP_RETRY_MAYFAIL);
        if (!charged)
                return -ENOMEM;

        /* pre-charge to forward_alloc */
        allocated = sk_memory_allocated_add(sk, pages);
        /* If the system goes into memory pressure with this
         * precharge, give up and return error.
         */
        if (allocated > sk_prot_mem_limits(sk, 1)) {
                sk_memory_allocated_sub(sk, pages);
                mem_cgroup_uncharge_skmem(sk->sk_memcg, pages);
                return -ENOMEM;
        }
        sk->sk_forward_alloc += pages << SK_MEM_QUANTUM_SHIFT;

        sk->sk_reserved_mem += pages << SK_MEM_QUANTUM_SHIFT;

        return 0;
}

/*
 *      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,
                    sockptr_t optval, unsigned int optlen)
{
        struct so_timestamping timestamping;
        struct sock_txtime sk_txtime;
        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 (copy_from_sockptr(&val, optval, sizeof(val)))
                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);
                sk_dst_reset(sk);
                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:
                /* Ensure val * 2 fits into an int, to prevent max_t()
                 * from treating it as a negative value.
                 */
                val = min_t(int, val, INT_MAX / 2);
                sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
                WRITE_ONCE(sk->sk_sndbuf,
                           max_t(int, 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;
                }

                /* No negative values (to prevent underflow, as val will be
                 * multiplied by 2).
                 */
                if (val < 0)
                        val = 0;
                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
                 */
                __sock_set_rcvbuf(sk, min_t(u32, val, sysctl_rmem_max));
                break;

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

                /* No negative values (to prevent underflow, as val will be
                 * multiplied by 2).
                 */
                __sock_set_rcvbuf(sk, max(val, 0));
                break;

        case SO_KEEPALIVE:
                if (sk->sk_prot->keepalive)
                        sk->sk_prot->keepalive(sk, valbool);
                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_RAW) ||
                    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_sockptr(&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:
                break;

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

        case SO_TIMESTAMP_OLD:
        case SO_TIMESTAMP_NEW:
        case SO_TIMESTAMPNS_OLD:
        case SO_TIMESTAMPNS_NEW:
                sock_set_timestamp(sk, optname, valbool);
                break;

        case SO_TIMESTAMPING_NEW:
        case SO_TIMESTAMPING_OLD:
                if (optlen == sizeof(timestamping)) {
                        if (copy_from_sockptr(&timestamping, optval,
                                              sizeof(timestamping))) {
                                ret = -EFAULT;
                                break;
                        }
                } else {
                        memset(&timestamping, 0, sizeof(timestamping));
                        timestamping.flags = val;
                }
                ret = sock_set_timestamping(sk, optname, timestamping);
                break;

        case SO_RCVLOWAT:
                if (val < 0)
                        val = INT_MAX;
                if (sock->ops->set_rcvlowat)
                        ret = sock->ops->set_rcvlowat(sk, val);
                else
                        WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
                break;

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

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

        case SO_ATTACH_FILTER: {
                struct sock_fprog fprog;

                ret = copy_bpf_fprog_from_user(&fprog, optval, optlen);
                if (!ret)
                        ret = sk_attach_filter(&fprog, sk);
                break;
        }
        case SO_ATTACH_BPF:
                ret = -EINVAL;
                if (optlen == sizeof(u32)) {
                        u32 ufd;

                        ret = -EFAULT;
                        if (copy_from_sockptr(&ufd, optval, sizeof(ufd)))
                                break;

                        ret = sk_attach_bpf(ufd, sk);
                }
                break;

        case SO_ATTACH_REUSEPORT_CBPF: {
                struct sock_fprog fprog;

                ret = copy_bpf_fprog_from_user(&fprog, optval, optlen);
                if (!ret)
                        ret = sk_reuseport_attach_filter(&fprog, sk);
                break;
        }
        case SO_ATTACH_REUSEPORT_EBPF:
                ret = -EINVAL;
                if (optlen == sizeof(u32)) {
                        u32 ufd;

                        ret = -EFAULT;
                        if (copy_from_sockptr(&ufd, optval, sizeof(ufd)))
                                break;

                        ret = sk_reuseport_attach_bpf(ufd, sk);
                }
                break;

        case SO_DETACH_REUSEPORT_BPF:
                ret = reuseport_detach_prog(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_RAW) &&
                    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
                        ret = -EPERM;
                        break;
                }

                __sock_set_mark(sk, val);
                break;
        case SO_RCVMARK:
                if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) &&
                    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
                        ret = -EPERM;
                        break;
                }

                sock_valbool_flag(sk, SOCK_RCVMARK, valbool);
                break;

        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
                                WRITE_ONCE(sk->sk_ll_usec, val);
                }
                break;
        case SO_PREFER_BUSY_POLL:
                if (valbool && !capable(CAP_NET_ADMIN))
                        ret = -EPERM;
                else
                        WRITE_ONCE(sk->sk_prefer_busy_poll, valbool);
                break;
        case SO_BUSY_POLL_BUDGET:
                if (val > READ_ONCE(sk->sk_busy_poll_budget) && !capable(CAP_NET_ADMIN)) {
                        ret = -EPERM;
                } else {
                        if (val < 0 || val > U16_MAX)
                                ret = -EINVAL;
                        else
                                WRITE_ONCE(sk->sk_busy_poll_budget, val);
                }
                break;
#endif

        case SO_MAX_PACING_RATE:
                {
                unsigned long ulval = (val == ~0U) ? ~0UL : (unsigned int)val;

                if (sizeof(ulval) != sizeof(val) &&
                    optlen >= sizeof(ulval) &&
                    copy_from_sockptr(&ulval, optval, sizeof(ulval))) {
                        ret = -EFAULT;
                        break;
                }
                if (ulval != ~0UL)
                        cmpxchg(&sk->sk_pacing_status,
                                SK_PACING_NONE,
                                SK_PACING_NEEDED);
                sk->sk_max_pacing_rate = ulval;
                sk->sk_pacing_rate = min(sk->sk_pacing_rate, ulval);
                break;
                }
        case SO_INCOMING_CPU:
                WRITE_ONCE(sk->sk_incoming_cpu, val);
                break;

        case SO_CNX_ADVICE:
                if (val == 1)
                        dst_negative_advice(sk);
                break;

        case SO_ZEROCOPY:
                if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6) {
                        if (!(sk_is_tcp(sk) ||
                              (sk->sk_type == SOCK_DGRAM &&
                               sk->sk_protocol == IPPROTO_UDP)))
                                ret = -EOPNOTSUPP;
                } else if (sk->sk_family != PF_RDS) {
                        ret = -EOPNOTSUPP;
                }
                if (!ret) {
                        if (val < 0 || val > 1)
                                ret = -EINVAL;
                        else
                                sock_valbool_flag(sk, SOCK_ZEROCOPY, valbool);
                }
                break;

        case SO_TXTIME:
                if (optlen != sizeof(struct sock_txtime)) {
                        ret = -EINVAL;
                        break;
                } else if (copy_from_sockptr(&sk_txtime, optval,
                           sizeof(struct sock_txtime))) {
                        ret = -EFAULT;
                        break;
                } else if (sk_txtime.flags & ~SOF_TXTIME_FLAGS_MASK) {
                        ret = -EINVAL;
                        break;
                }
                /* CLOCK_MONOTONIC is only used by sch_fq, and this packet
                 * scheduler has enough safe guards.
                 */
                if (sk_txtime.clockid != CLOCK_MONOTONIC &&
                    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
                        ret = -EPERM;
                        break;
                }
                sock_valbool_flag(sk, SOCK_TXTIME, true);
                sk->sk_clockid = sk_txtime.clockid;
                sk->sk_txtime_deadline_mode =
                        !!(sk_txtime.flags & SOF_TXTIME_DEADLINE_MODE);
                sk->sk_txtime_report_errors =
                        !!(sk_txtime.flags & SOF_TXTIME_REPORT_ERRORS);
                break;

        case SO_BINDTOIFINDEX:
                ret = sock_bindtoindex_locked(sk, val);
                break;

        case SO_BUF_LOCK:
                if (val & ~SOCK_BUF_LOCK_MASK) {
                        ret = -EINVAL;
                        break;
                }
                sk->sk_userlocks = val | (sk->sk_userlocks &
                                          ~SOCK_BUF_LOCK_MASK);
                break;

        case SO_RESERVE_MEM:
        {
                int delta;

                if (val < 0) {
                        ret = -EINVAL;
                        break;
                }

                delta = val - sk->sk_reserved_mem;
                if (delta < 0)
                        sock_release_reserved_memory(sk, -delta);
                else
                        ret = sock_reserve_memory(sk, delta);
                break;
        }

        case SO_TXREHASH:
                if (val < -1 || val > 1) {
                        ret = -EINVAL;
                        break;
                }
                /* Paired with READ_ONCE() in tcp_rtx_synack() */
                WRITE_ONCE(sk->sk_txrehash, (u8)val);
                break;

        default:
                ret = -ENOPROTOOPT;
                break;
        }
        release_sock(sk);
        return ret;
}
EXPORT_SYMBOL(sock_setsockopt);

static const struct cred *sk_get_peer_cred(struct sock *sk)
{
        const struct cred *cred;

        spin_lock(&sk->sk_peer_lock);
        cred = get_cred(sk->sk_peer_cred);
        spin_unlock(&sk->sk_peer_lock);

        return cred;
}

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);
        }
}

static int groups_to_user(gid_t __user *dst, const struct group_info *src)
{
        struct user_namespace *user_ns = current_user_ns();
        int i;

        for (i = 0; i < src->ngroups; i++)
                if (put_user(from_kgid_munged(user_ns, src->gid[i]), dst + i))
                        return -EFAULT;

        return 0;
}

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

        union {
                int val;
                u64 val64;
                unsigned long ulval;
                struct linger ling;
                struct old_timeval32 tm32;
                struct __kernel_old_timeval tm;
                struct  __kernel_sock_timeval stm;
                struct sock_txtime txtime;
                struct so_timestamping timestamping;
        } 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:
                break;

        case SO_TIMESTAMP_OLD:
                v.val = sock_flag(sk, SOCK_RCVTSTAMP) &&
                                !sock_flag(sk, SOCK_TSTAMP_NEW) &&
                                !sock_flag(sk, SOCK_RCVTSTAMPNS);
                break;

        case SO_TIMESTAMPNS_OLD:
                v.val = sock_flag(sk, SOCK_RCVTSTAMPNS) && !sock_flag(sk, SOCK_TSTAMP_NEW);
                break;

        case SO_TIMESTAMP_NEW:
                v.val = sock_flag(sk, SOCK_RCVTSTAMP) && sock_flag(sk, SOCK_TSTAMP_NEW);
                break;

        case SO_TIMESTAMPNS_NEW:
                v.val = sock_flag(sk, SOCK_RCVTSTAMPNS) && sock_flag(sk, SOCK_TSTAMP_NEW);
                break;

        case SO_TIMESTAMPING_OLD:
                lv = sizeof(v.timestamping);
                v.timestamping.flags = sk->sk_tsflags;
                v.timestamping.bind_phc = sk->sk_bind_phc;
                break;

        case SO_RCVTIMEO_OLD:
        case SO_RCVTIMEO_NEW:
                lv = sock_get_timeout(sk->sk_rcvtimeo, &v, SO_RCVTIMEO_OLD == optname);
                break;

        case SO_SNDTIMEO_OLD:
        case SO_SNDTIMEO_NEW:
                lv = sock_get_timeout(sk->sk_sndtimeo, &v, SO_SNDTIMEO_OLD == optname);
                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);

                spin_lock(&sk->sk_peer_lock);
                cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred);
                spin_unlock(&sk->sk_peer_lock);

                if (copy_to_user(optval, &peercred, len))
                        return -EFAULT;
                goto lenout;
        }

        case SO_PEERGROUPS:
        {
                const struct cred *cred;
                int ret, n;

                cred = sk_get_peer_cred(sk);
                if (!cred)
                        return -ENODATA;

                n = cred->group_info->ngroups;
                if (len < n * sizeof(gid_t)) {
                        len = n * sizeof(gid_t);
                        put_cred(cred);
                        return put_user(len, optlen) ? -EFAULT : -ERANGE;
                }
                len = n * sizeof(gid_t);

                ret = groups_to_user((gid_t __user *)optval, cred->group_info);
                put_cred(cred);
                if (ret)
                        return ret;
                goto lenout;
        }

        case SO_PEERNAME:
        {
                char address[128];

                lv = sock->ops->getname(sock, (struct sockaddr *)address, 2);
                if (lv < 0)
                        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_RCVMARK:
                v.val = sock_flag(sk, SOCK_RCVMARK);
                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;
        case SO_PREFER_BUSY_POLL:
                v.val = READ_ONCE(sk->sk_prefer_busy_poll);
                break;
#endif

        case SO_MAX_PACING_RATE:
                if (sizeof(v.ulval) != sizeof(v.val) && len >= sizeof(v.ulval)) {
                        lv = sizeof(v.ulval);
                        v.ulval = sk->sk_max_pacing_rate;
                } else {
                        /* 32bit version */
                        v.val = min_t(unsigned long, sk->sk_max_pacing_rate, ~0U);
                }
                break;

        case SO_INCOMING_CPU:
                v.val = READ_ONCE(sk->sk_incoming_cpu);
                break;

        case SO_MEMINFO:
        {
                u32 meminfo[SK_MEMINFO_VARS];

                sk_get_meminfo(sk, meminfo);

                len = min_t(unsigned int, len, sizeof(meminfo));
                if (copy_to_user(optval, &meminfo, len))
                        return -EFAULT;

                goto lenout;
        }

#ifdef CONFIG_NET_RX_BUSY_POLL
        case SO_INCOMING_NAPI_ID:
                v.val = READ_ONCE(sk->sk_napi_id);

                /* aggregate non-NAPI IDs down to 0 */
                if (v.val < MIN_NAPI_ID)
                        v.val = 0;

                break;
#endif

        case SO_COOKIE:
                lv = sizeof(u64);
                if (len < lv)
                        return -EINVAL;
                v.val64 = sock_gen_cookie(sk);
                break;

        case SO_ZEROCOPY:
                v.val = sock_flag(sk, SOCK_ZEROCOPY);
                break;

        case SO_TXTIME:
                lv = sizeof(v.txtime);
                v.txtime.clockid = sk->sk_clockid;
                v.txtime.flags |= sk->sk_txtime_deadline_mode ?
                                  SOF_TXTIME_DEADLINE_MODE : 0;
                v.txtime.flags |= sk->sk_txtime_report_errors ?
                                  SOF_TXTIME_REPORT_ERRORS : 0;
                break;

        case SO_BINDTOIFINDEX:
                v.val = READ_ONCE(sk->sk_bound_dev_if);
                break;

        case SO_NETNS_COOKIE:
                lv = sizeof(u64);
                if (len != lv)
                        return -EINVAL;
                v.val64 = sock_net(sk)->net_cookie;
                break;

        case SO_BUF_LOCK:
                v.val = sk->sk_userlocks & SOCK_BUF_LOCK_MASK;
                break;

        case SO_RESERVE_MEM:
                v.val = sk->sk_reserved_mem;
                break;

        case SO_TXREHASH:
                v.val = sk->sk_txrehash;
                break;

        default:
                /* We implement the SO_SNDLOWAT etc to not be settable
                 * (1003.1g 7).
                 */
                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)
{
        if (sk->sk_kern_sock)
                sock_lock_init_class_and_name(
                        sk,
                        af_family_kern_slock_key_strings[sk->sk_family],
                        af_family_kern_slock_keys + sk->sk_family,
                        af_family_kern_key_strings[sk->sk_family],
                        af_family_kern_keys + sk->sk_family);
        else
                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)
{
        const struct proto *prot = READ_ONCE(osk->sk_prot);
#ifdef CONFIG_SECURITY_NETWORK
        void *sptr = nsk->sk_security;
#endif

        /* If we move sk_tx_queue_mapping out of the private section,
         * we must check if sk_tx_queue_clear() is called after
         * sock_copy() in sk_clone_lock().
         */
        BUILD_BUG_ON(offsetof(struct sock, sk_tx_queue_mapping) <
                     offsetof(struct sock, sk_dontcopy_begin) ||
                     offsetof(struct sock, sk_tx_queue_mapping) >=
                     offsetof(struct sock, sk_dontcopy_end));

        memcpy(nsk, osk, offsetof(struct sock, sk_dontcopy_begin));

        memcpy(&nsk->sk_dontcopy_end, &osk->sk_dontcopy_end,
               prot->obj_size - offsetof(struct sock, sk_dontcopy_end));

#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 & ~__GFP_ZERO);
                if (!sk)
                        return sk;
                if (want_init_on_alloc(priority))
                        sk_prot_clear_nulls(sk, prot->obj_size);
        } 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;

        cgroup_sk_free(&sk->sk_cgrp_data);
        mem_cgroup_sk_free(sk);
        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
 *      @kern: is this to be a kernel socket?
 */
struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
                      struct proto *prot, int kern)
{
        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;
                sk->sk_kern_sock = kern;
                sock_lock_init(sk);
                sk->sk_net_refcnt = kern ? 0 : 1;
                if (likely(sk->sk_net_refcnt)) {
                        get_net_track(net, &sk->ns_tracker, priority);
                        sock_inuse_add(net, 1);
                }

                sock_net_set(sk, net);
                refcount_set(&sk->sk_wmem_alloc, 1);

                mem_cgroup_sk_alloc(sk);
                cgroup_sk_alloc(&sk->sk_cgrp_data);
                sock_update_classid(&sk->sk_cgrp_data);
                sock_update_netprioidx(&sk->sk_cgrp_data);
                sk_tx_queue_clear(sk);
        }

        return sk;
}
EXPORT_SYMBOL(sk_alloc);

/* Sockets having SOCK_RCU_FREE will call this function after one RCU
 * grace period. This is the case for UDP sockets and TCP listeners.
 */
static void __sk_destruct(struct rcu_head *head)
{
        struct sock *sk = container_of(head, struct sock, sk_rcu);
        struct sk_filter *filter;

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

        filter = rcu_dereference_check(sk->sk_filter,
                                       refcount_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);

#ifdef CONFIG_BPF_SYSCALL
        bpf_sk_storage_free(sk);
#endif

        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_frag.page) {
                put_page(sk->sk_frag.page);
                sk->sk_frag.page = NULL;
        }

        /* We do not need to acquire sk->sk_peer_lock, we are the last user. */
        put_cred(sk->sk_peer_cred);
        put_pid(sk->sk_peer_pid);

        if (likely(sk->sk_net_refcnt))
                put_net_track(sock_net(sk), &sk->ns_tracker);
        sk_prot_free(sk->sk_prot_creator, sk);
}

void sk_destruct(struct sock *sk)
{
        bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE);

        if (rcu_access_pointer(sk->sk_reuseport_cb)) {
                reuseport_detach_sock(sk);
                use_call_rcu = true;
        }

        if (use_call_rcu)
                call_rcu(&sk->sk_rcu, __sk_destruct);
        else
                __sk_destruct(&sk->sk_rcu);
}

static void __sk_free(struct sock *sk)
{
        if (likely(sk->sk_net_refcnt))
                sock_inuse_add(sock_net(sk), -1);

        if (unlikely(sk->sk_net_refcnt && sock_diag_has_destroy_listeners(sk)))
                sock_diag_broadcast_destroy(sk);
        else
                sk_destruct(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 (refcount_dec_and_test(&sk->sk_wmem_alloc))
                __sk_free(sk);
}
EXPORT_SYMBOL(sk_free);

static void sk_init_common(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);

        rwlock_init(&sk->sk_callback_lock);
        lockdep_set_class_and_name(&sk->sk_receive_queue.lock,
                        af_rlock_keys + sk->sk_family,
                        af_family_rlock_key_strings[sk->sk_family]);
        lockdep_set_class_and_name(&sk->sk_write_queue.lock,
                        af_wlock_keys + sk->sk_family,
                        af_family_wlock_key_strings[sk->sk_family]);
        lockdep_set_class_and_name(&sk->sk_error_queue.lock,
                        af_elock_keys + sk->sk_family,
                        af_family_elock_key_strings[sk->sk_family]);
        lockdep_set_class_and_name(&sk->sk_callback_lock,
                        af_callback_keys + sk->sk_family,
                        af_family_clock_key_strings[sk->sk_family]);
}

/**
 *      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 proto *prot = READ_ONCE(sk->sk_prot);
        struct sk_filter *filter;
        bool is_charged = true;
        struct sock *newsk;

        newsk = sk_prot_alloc(prot, priority, sk->sk_family);
        if (!newsk)
                goto out;

        sock_copy(newsk, sk);

        newsk->sk_prot_creator = prot;

        /* SANITY */
        if (likely(newsk->sk_net_refcnt)) {
                get_net_track(sock_net(newsk), &newsk->ns_tracker, priority);
                sock_inuse_add(sock_net(newsk), 1);
        }
        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()) */
        refcount_set(&newsk->sk_wmem_alloc, 1);

        atomic_set(&newsk->sk_omem_alloc, 0);
        sk_init_common(newsk);

        newsk->sk_dst_cache     = NULL;
        newsk->sk_dst_pending_confirm = 0;
        newsk->sk_wmem_queued   = 0;
        newsk->sk_forward_alloc = 0;
        newsk->sk_reserved_mem  = 0;
        atomic_set(&newsk->sk_drops, 0);
        newsk->sk_send_head     = NULL;
        newsk->sk_userlocks     = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;
        atomic_set(&newsk->sk_zckey, 0);

        sock_reset_flag(newsk, SOCK_DONE);

        /* sk->sk_memcg will be populated at accept() time */
        newsk->sk_memcg = NULL;

        cgroup_sk_clone(&newsk->sk_cgrp_data);

        rcu_read_lock();
        filter = rcu_dereference(sk->sk_filter);
        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);
        RCU_INIT_POINTER(newsk->sk_filter, filter);
        rcu_read_unlock();

        if (unlikely(!is_charged || xfrm_sk_clone_policy(newsk, sk))) {
                /* We need to make sure that we don't uncharge the new
                 * socket if we couldn't charge it in the first place
                 * as otherwise we uncharge the parent's filter.
                 */
                if (!is_charged)
                        RCU_INIT_POINTER(newsk->sk_filter, NULL);
                sk_free_unlock_clone(newsk);
                newsk = NULL;
                goto out;
        }
        RCU_INIT_POINTER(newsk->sk_reuseport_cb, NULL);

        if (bpf_sk_storage_clone(sk, newsk)) {
                sk_free_unlock_clone(newsk);
                newsk = NULL;
                goto out;
        }

        /* Clear sk_user_data if parent had the pointer tagged
         * as not suitable for copying when cloning.
         */
        if (sk_user_data_is_nocopy(newsk))
                newsk->sk_user_data = NULL;

        newsk->sk_err      = 0;
        newsk->sk_err_soft = 0;
        newsk->sk_priority = 0;
        newsk->sk_incoming_cpu = raw_smp_processor_id();

        /* Before updating sk_refcnt, we must commit prior changes to memory
         * (Documentation/RCU/rculist_nulls.rst for details)
         */
        smp_wmb();
        refcount_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);
        sk_tx_queue_clear(newsk);
        RCU_INIT_POINTER(newsk->sk_wq, NULL);

        if (newsk->sk_prot->sockets_allocated)
                sk_sockets_allocated_inc(newsk);

        if (sock_needs_netstamp(sk) && newsk->sk_flags & SK_FLAGS_TIMESTAMP)
                net_enable_timestamp();
out:
        return newsk;
}
EXPORT_SYMBOL_GPL(sk_clone_lock);

void sk_free_unlock_clone(struct sock *sk)
{
        /* It is still raw copy of parent, so invalidate
         * destructor and make plain sk_free() */
        sk->sk_destruct = NULL;
        bh_unlock_sock(sk);
        sk_free(sk);
}
EXPORT_SYMBOL_GPL(sk_free_unlock_clone);

static void sk_trim_gso_size(struct sock *sk)
{
        if (sk->sk_gso_max_size <= GSO_LEGACY_MAX_SIZE)
                return;
#if IS_ENABLED(CONFIG_IPV6)
        if (sk->sk_family == AF_INET6 &&
            sk_is_tcp(sk) &&
            !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
                return;
#endif
        sk->sk_gso_max_size = GSO_LEGACY_MAX_SIZE;
}

void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
{
        u32 max_segs = 1;

        sk_dst_set(sk, dst);
        sk->sk_route_caps = dst->dev->features;
        if (sk_is_tcp(sk))
                sk->sk_route_caps |= NETIF_F_GSO;
        if (sk->sk_route_caps & NETIF_F_GSO)
                sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
        if (unlikely(sk->sk_gso_disabled))
                sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
        if (sk_can_gso(sk)) {
                if (dst->header_len && !xfrm_dst_offload_ok(dst)) {
                        sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
                } else {
                        sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
                        /* pairs with the WRITE_ONCE() in netif_set_gso_max_size() */
                        sk->sk_gso_max_size = READ_ONCE(dst->dev->gso_max_size);
                        sk_trim_gso_size(sk);
                        sk->sk_gso_max_size -= (MAX_TCP_HEADER + 1);
                        /* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */
                        max_segs = max_t(u32, READ_ONCE(dst->dev->gso_max_segs), 1);
                }
        }
        sk->sk_gso_max_segs = 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;
        bool free;

        if (!sock_flag(sk, SOCK_USE_WRITE_QUEUE)) {
                if (sock_flag(sk, SOCK_RCU_FREE) &&
                    sk->sk_write_space == sock_def_write_space) {
                        rcu_read_lock();
                        free = refcount_sub_and_test(len, &sk->sk_wmem_alloc);
                        sock_def_write_space_wfree(sk);
                        rcu_read_unlock();
                        if (unlikely(free))
                                __sk_free(sk);
                        return;
                }

                /*
                 * Keep a reference on sk_wmem_alloc, this will be released
                 * after sk_write_space() call
                 */
                WARN_ON(refcount_sub_and_test(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 (refcount_sub_and_test(len, &sk->sk_wmem_alloc))
                __sk_free(sk);
}
EXPORT_SYMBOL(sock_wfree);

/* This variant of sock_wfree() is used by TCP,
 * since it sets SOCK_USE_WRITE_QUEUE.
 */
void __sock_wfree(struct sk_buff *skb)
{
        struct sock *sk = skb->sk;

        if (refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc))
                __sk_free(sk);
}

void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
{
        skb_orphan(skb);
        skb->sk = sk;
#ifdef CONFIG_INET
        if (unlikely(!sk_fullsock(sk))) {
                skb->destructor = sock_edemux;
                sock_hold(sk);
                return;
        }
#endif
        skb->destructor = sock_wfree;
        skb_set_hash_from_sk(skb, sk);
        /*
         * We used to take a refcount on sk, but following operation
         * is enough to guarantee sk_free() wont free this sock until
         * all in-flight packets are completed
         */
        refcount_add(skb->truesize, &sk->sk_wmem_alloc);
}
EXPORT_SYMBOL(skb_set_owner_w);

static bool can_skb_orphan_partial(const struct sk_buff *skb)
{
#ifdef CONFIG_TLS_DEVICE
        /* Drivers depend on in-order delivery for crypto offload,
         * partial orphan breaks out-of-order-OK logic.
         */
        if (skb->decrypted)
                return false;
#endif
        return (skb->destructor == sock_wfree ||
                (IS_ENABLED(CONFIG_INET) && skb->destructor == tcp_wfree));
}

/* This helper is used by netem, as it can hold packets in its
 * delay queue. We want to allow the owner socket to send more
 * packets, as if they were already TX completed by a typical driver.
 * But we also want to keep skb->sk set because some packet schedulers
 * rely on it (sch_fq for example).
 */
void skb_orphan_partial(struct sk_buff *skb)
{
        if (skb_is_tcp_pure_ack(skb))
                return;

        if (can_skb_orphan_partial(skb) && skb_set_owner_sk_safe(skb, skb->sk))
                return;

        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);

/*
 * Buffer destructor for skbs that are not used directly in read or write
 * path, e.g. for error handler skbs. Automatically called from kfree_skb.
 */
void sock_efree(struct sk_buff *skb)
{
        sock_put(skb->sk);
}
EXPORT_SYMBOL(sock_efree);

/* Buffer destructor for prefetch/receive path where reference count may
 * not be held, e.g. for listen sockets.
 */
#ifdef CONFIG_INET
void sock_pfree(struct sk_buff *skb)
{
        if (sk_is_refcounted(skb->sk))
                sock_gen_put(skb->sk);
}
EXPORT_SYMBOL(sock_pfree);
#endif /* CONFIG_INET */

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 ||
            refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(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);

static void sock_ofree(struct sk_buff *skb)
{
        struct sock *sk = skb->sk;

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

struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
                             gfp_t priority)
{
        struct sk_buff *skb;

        /* small safe race: SKB_TRUESIZE may differ from final skb->truesize */
        if (atomic_read(&sk->sk_omem_alloc) + SKB_TRUESIZE(size) >
            sysctl_optmem_max)
                return NULL;

        skb = alloc_skb(size, priority);
        if (!skb)
                return NULL;

        atomic_add(skb->truesize, &sk->sk_omem_alloc);
        skb->sk = sk;
        skb->destructor = sock_ofree;
        return skb;
}

/*
 * 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. Note, we actually want the inline
 * here as this allows gcc to detect the nullify and fold away the
 * condition entirely.
 */
static inline void __sock_kfree_s(struct sock *sk, void *mem, int size,
                                  const bool nullify)
{
        if (WARN_ON_ONCE(!mem))
                return;
        if (nullify)
                kfree_sensitive(mem);
        else
                kfree(mem);
        atomic_sub(size, &sk->sk_omem_alloc);
}

void sock_kfree_s(struct sock *sk, void *mem, int size)
{
        __sock_kfree_s(sk, mem, size, false);
}
EXPORT_SYMBOL(sock_kfree_s);

void sock_kzfree_s(struct sock *sk, void *mem, int size)
{
        __sock_kfree_s(sk, mem, size, true);
}
EXPORT_SYMBOL(sock_kzfree_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);

        sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
        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 (refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(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;
        long timeo;
        int err;

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

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

                if (sk_wmem_alloc_get(sk) < READ_ONCE(sk->sk_sndbuf))
                        break;

                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
                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 = alloc_skb_with_frags(header_len, data_len, max_page_order,
                                   errcode, sk->sk_allocation);
        if (skb)
                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);

int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
                     struct sockcm_cookie *sockc)
{
        u32 tsflags;

        switch (cmsg->cmsg_type) {
        case SO_MARK:
                if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) &&
                    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
                        return -EPERM;
                if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
                        return -EINVAL;
                sockc->mark = *(u32 *)CMSG_DATA(cmsg);
                break;
        case SO_TIMESTAMPING_OLD:
                if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
                        return -EINVAL;

                tsflags = *(u32 *)CMSG_DATA(cmsg);
                if (tsflags & ~SOF_TIMESTAMPING_TX_RECORD_MASK)
                        return -EINVAL;

                sockc->tsflags &= ~SOF_TIMESTAMPING_TX_RECORD_MASK;
                sockc->tsflags |= tsflags;
                break;
        case SCM_TXTIME:
                if (!sock_flag(sk, SOCK_TXTIME))
                        return -EINVAL;
                if (cmsg->cmsg_len != CMSG_LEN(sizeof(u64)))
                        return -EINVAL;
                sockc->transmit_time = get_unaligned((u64 *)CMSG_DATA(cmsg));
                break;
        /* SCM_RIGHTS and SCM_CREDENTIALS are semantically in SOL_UNIX. */
        case SCM_RIGHTS:
        case SCM_CREDENTIALS:
                break;
        default:
                return -EINVAL;
        }
        return 0;
}
EXPORT_SYMBOL(__sock_cmsg_send);

int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
                   struct sockcm_cookie *sockc)
{
        struct cmsghdr *cmsg;
        int ret;

        for_each_cmsghdr(cmsg, msg) {
                if (!CMSG_OK(msg, cmsg))
                        return -EINVAL;
                if (cmsg->cmsg_level != SOL_SOCKET)
                        continue;
                ret = __sock_cmsg_send(sk, msg, cmsg, sockc);
                if (ret)
                        return ret;
        }
        return 0;
}
EXPORT_SYMBOL(sock_cmsg_send);

static void sk_enter_memory_pressure(struct sock *sk)
{
        if (!sk->sk_prot->enter_memory_pressure)
                return;

        sk->sk_prot->enter_memory_pressure(sk);
}

static void sk_leave_memory_pressure(struct sock *sk)
{
        if (sk->sk_prot->leave_memory_pressure) {
                sk->sk_prot->leave_memory_pressure(sk);
        } else {
                unsigned long *memory_pressure = sk->sk_prot->memory_pressure;

                if (memory_pressure && READ_ONCE(*memory_pressure))
                        WRITE_ONCE(*memory_pressure, 0);
        }
}

DEFINE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);

/**
 * 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
 * @gfp: 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 (page_ref_count(pfrag->page) == 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 &&
            !static_branch_unlikely(&net_high_order_alloc_disable_key)) {
                /* Avoid direct reclaim but allow kswapd to wake */
                pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
                                          __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);

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);
}

void __release_sock(struct sock *sk)
        __releases(&sk->sk_lock.slock)
        __acquires(&sk->sk_lock.slock)
{
        struct sk_buff *skb, *next;

        while ((skb = sk->sk_backlog.head) != NULL) {
                sk->sk_backlog.head = sk->sk_backlog.tail = NULL;

                spin_unlock_bh(&sk->sk_lock.slock);

                do {
                        next = skb->next;
                        prefetch(next);
                        WARN_ON_ONCE(skb_dst_is_noref(skb));
                        skb_mark_not_on_list(skb);
                        sk_backlog_rcv(sk, skb);

                        cond_resched();

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

                spin_lock_bh(&sk->sk_lock.slock);
        }

        /*
         * Doing the zeroing here guarantee we can not loop forever
         * while a wild producer attempts to flood us.
         */
        sk->sk_backlog.len = 0;
}

void __sk_flush_backlog(struct sock *sk)
{
        spin_lock_bh(&sk->sk_lock.slock);
        __release_sock(sk);
        spin_unlock_bh(&sk->sk_lock.slock);
}

/**
 * sk_wait_data - wait for data to arrive at sk_receive_queue
 * @sk:    sock to wait on
 * @timeo: for how long
 * @skb:   last skb seen on sk_receive_queue
 *
 * 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, const struct sk_buff *skb)
{
        DEFINE_WAIT_FUNC(wait, woken_wake_function);
        int rc;

        add_wait_queue(sk_sleep(sk), &wait);
        sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
        rc = sk_wait_event(sk, timeo, skb_peek_tail(&sk->sk_receive_queue) != skb, &wait);
        sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
        remove_wait_queue(sk_sleep(sk), &wait);
        return rc;
}
EXPORT_SYMBOL(sk_wait_data);

/**
 *      __sk_mem_raise_allocated - increase memory_allocated
 *      @sk: socket
 *      @size: memory size to allocate
 *      @amt: pages to allocate
 *      @kind: allocation type
 *
 *      Similar to __sk_mem_schedule(), but does not update sk_forward_alloc
 */
int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
{
        struct proto *prot = sk->sk_prot;
        long allocated = sk_memory_allocated_add(sk, amt);
        bool memcg_charge = mem_cgroup_sockets_enabled && sk->sk_memcg;
        bool charged = true;

        if (memcg_charge &&
            !(charged = mem_cgroup_charge_skmem(sk->sk_memcg, amt,
                                                gfp_memcg_charge())))
                goto suppress_allocation;

        /* Under limit. */
        if (allocated <= sk_prot_mem_limits(sk, 0)) {
                sk_leave_memory_pressure(sk);
                return 1;
        }

        /* Under pressure. */
        if (allocated > sk_prot_mem_limits(sk, 1))
                sk_enter_memory_pressure(sk);

        /* Over hard limit. */
        if (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) < sk_get_rmem0(sk, prot))
                        return 1;

        } else { /* SK_MEM_SEND */
                int wmem0 = sk_get_wmem0(sk, prot);

                if (sk->sk_type == SOCK_STREAM) {
                        if (sk->sk_wmem_queued < wmem0)
                                return 1;
                } else if (refcount_read(&sk->sk_wmem_alloc) < wmem0) {
                                return 1;
                }
        }

        if (sk_has_memory_pressure(sk)) {
                u64 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) {
                        /* Force charge with __GFP_NOFAIL */
                        if (memcg_charge && !charged) {
                                mem_cgroup_charge_skmem(sk->sk_memcg, amt,
                                        gfp_memcg_charge() | __GFP_NOFAIL);
                        }
                        return 1;
                }
        }

        if (kind == SK_MEM_SEND || (kind == SK_MEM_RECV && charged))
                trace_sock_exceed_buf_limit(sk, prot, allocated, kind);

        sk_memory_allocated_sub(sk, amt);

        if (memcg_charge && charged)
                mem_cgroup_uncharge_skmem(sk->sk_memcg, amt);

        return 0;
}
EXPORT_SYMBOL(__sk_mem_raise_allocated);

/**
 *      __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)
{
        int ret, amt = sk_mem_pages(size);

        sk->sk_forward_alloc += amt << SK_MEM_QUANTUM_SHIFT;
        ret = __sk_mem_raise_allocated(sk, size, amt, kind);
        if (!ret)
                sk->sk_forward_alloc -= amt << SK_MEM_QUANTUM_SHIFT;
        return ret;
}
EXPORT_SYMBOL(__sk_mem_schedule);

/**
 *      __sk_mem_reduce_allocated - reclaim memory_allocated
 *      @sk: socket
 *      @amount: number of quanta
 *
 *      Similar to __sk_mem_reclaim(), but does not update sk_forward_alloc
 */
void __sk_mem_reduce_allocated(struct sock *sk, int amount)
{
        sk_memory_allocated_sub(sk, amount);

        if (mem_cgroup_sockets_enabled && sk->sk_memcg)
                mem_cgroup_uncharge_skmem(sk->sk_memcg, amount);

        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_reduce_allocated);

/**
 *      __sk_mem_reclaim - reclaim sk_forward_alloc and memory_allocated
 *      @sk: socket
 *      @amount: number of bytes (rounded down to a SK_MEM_QUANTUM multiple)
 */
void __sk_mem_reclaim(struct sock *sk, int amount)
{
        amount >>= SK_MEM_QUANTUM_SHIFT;
        sk->sk_forward_alloc -= amount << SK_MEM_QUANTUM_SHIFT;
        __sk_mem_reduce_allocated(sk, amount);
}
EXPORT_SYMBOL(__sk_mem_reclaim);

int sk_set_peek_off(struct sock *sk, int val)
{
        sk->sk_peek_off = val;
        return 0;
}
EXPORT_SYMBOL_GPL(sk_set_peek_off);

/*
 * 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,
                   bool kern)
{
        return -EOPNOTSUPP;
}
EXPORT_SYMBOL(sock_no_accept);

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

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_sendmsg(struct socket *sock, struct msghdr *m, size_t len)
{
        return -EOPNOTSUPP;
}
EXPORT_SYMBOL(sock_no_sendmsg);

int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *m, size_t len)
{
        return -EOPNOTSUPP;
}
EXPORT_SYMBOL(sock_no_sendmsg_locked);

int sock_no_recvmsg(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);

/*
 * When a file is received (via SCM_RIGHTS, etc), we must bump the
 * various sock-based usage counts.
 */
void __receive_sock(struct file *file)
{
        struct socket *sock;

        sock = sock_from_file(file);
        if (sock) {
                sock_update_netprioidx(&sock->sk->sk_cgrp_data);
                sock_update_classid(&sock->sk->sk_cgrp_data);
        }
}

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);

ssize_t sock_no_sendpage_locked(struct sock *sk, 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_locked(sk, &msg, &iov, 1, size);
        kunmap(page);
        return res;
}
EXPORT_SYMBOL(sock_no_sendpage_locked);

/*
 *      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 (skwq_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 (skwq_has_sleeper(wq))
                wake_up_interruptible_poll(&wq->wait, EPOLLERR);
        sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
        rcu_read_unlock();
}

void sock_def_readable(struct sock *sk)
{
        struct socket_wq *wq;

        rcu_read_lock();
        wq = rcu_dereference(sk->sk_wq);
        if (skwq_has_sleeper(wq))
                wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI |
                                                EPOLLRDNORM | EPOLLRDBAND);
        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 (sock_writeable(sk)) {
                wq = rcu_dereference(sk->sk_wq);
                if (skwq_has_sleeper(wq))
                        wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
                                                EPOLLWRNORM | EPOLLWRBAND);

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

        rcu_read_unlock();
}

/* An optimised version of sock_def_write_space(), should only be called
 * for SOCK_RCU_FREE sockets under RCU read section and after putting
 * ->sk_wmem_alloc.
 */
static void sock_def_write_space_wfree(struct sock *sk)
{
        /* Do not wake up a writer until he can make "significant"
         * progress.  --DaveM
         */
        if (sock_writeable(sk)) {
                struct socket_wq *wq = rcu_dereference(sk->sk_wq);

                /* rely on refcount_sub from sock_wfree() */
                smp_mb__after_atomic();
                if (wq && waitqueue_active(&wq->wait))
                        wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
                                                EPOLLWRNORM | EPOLLWRBAND);

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

static void sock_def_destruct(struct sock *sk)
{
}

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 sk_stop_timer_sync(struct sock *sk, struct timer_list *timer)
{
        if (del_timer_sync(timer))
                __sock_put(sk);
}
EXPORT_SYMBOL(sk_stop_timer_sync);

void sock_init_data(struct socket *sock, struct sock *sk)
{
        sk_init_common(sk);
        sk->sk_send_head        =       NULL;

        timer_setup(&sk->sk_timer, NULL, 0);

        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;
                RCU_INIT_POINTER(sk->sk_wq, &sock->wq);
                sock->sk        =       sk;
                sk->sk_uid      =       SOCK_INODE(sock)->i_uid;
        } else {
                RCU_INIT_POINTER(sk->sk_wq, NULL);
                sk->sk_uid      =       make_kuid(sock_net(sk)->user_ns, 0);
        }

        rwlock_init(&sk->sk_callback_lock);
        if (sk->sk_kern_sock)
                lockdep_set_class_and_name(
                        &sk->sk_callback_lock,
                        af_kern_callback_keys + sk->sk_family,
                        af_family_kern_clock_key_strings[sk->sk_family]);
        else
                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;
        spin_lock_init(&sk->sk_peer_lock);

        sk->sk_write_pending    =       0;
        sk->sk_rcvlowat         =       1;
        sk->sk_rcvtimeo         =       MAX_SCHEDULE_TIMEOUT;
        sk->sk_sndtimeo         =       MAX_SCHEDULE_TIMEOUT;

        sk->sk_stamp = SK_DEFAULT_STAMP;
#if BITS_PER_LONG==32
        seqlock_init(&sk->sk_stamp_seq);
#endif
        atomic_set(&sk->sk_zckey, 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 = ~0UL;
        sk->sk_pacing_rate = ~0UL;
        WRITE_ONCE(sk->sk_pacing_shift, 10);
        sk->sk_incoming_cpu = -1;
        sk->sk_txrehash = SOCK_TXREHASH_DEFAULT;

        sk_rx_queue_clear(sk);
        /*
         * Before updating sk_refcnt, we must commit prior changes to memory
         * (Documentation/RCU/rculist_nulls.rst for details)
         */
        smp_wmb();
        refcount_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)
{
        /* The sk_lock has mutex_lock() semantics here. */
        mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);

        might_sleep();
        spin_lock_bh(&sk->sk_lock.slock);
        if (sock_owned_by_user_nocheck(sk))
                __lock_sock(sk);
        sk->sk_lock.owned = 1;
        spin_unlock_bh(&sk->sk_lock.slock);
}
EXPORT_SYMBOL(lock_sock_nested);

void release_sock(struct sock *sk)
{
        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);

bool __lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
{
        might_sleep();
        spin_lock_bh(&sk->sk_lock.slock);

        if (!sock_owned_by_user_nocheck(sk)) {
                /*
                 * Fast path return with bottom halves disabled and
                 * sock::sk_lock.slock held.
                 *
                 * The 'mutex' is not contended and holding
                 * sock::sk_lock.slock prevents all other lockers to
                 * proceed so the corresponding unlock_sock_fast() can
                 * avoid the slow path of release_sock() completely and
                 * just release slock.
                 *
                 * From a semantical POV this is equivalent to 'acquiring'
                 * the 'mutex', hence the corresponding lockdep
                 * mutex_release() has to happen in the fast path of
                 * unlock_sock_fast().
                 */
                return false;
        }

        __lock_sock(sk);
        sk->sk_lock.owned = 1;
        __acquire(&sk->sk_lock.slock);
        spin_unlock_bh(&sk->sk_lock.slock);
        return true;
}
EXPORT_SYMBOL(__lock_sock_fast);

int sock_gettstamp(struct socket *sock, void __user *userstamp,
                   bool timeval, bool time32)
{
        struct sock *sk = sock->sk;
        struct timespec64 ts;

        sock_enable_timestamp(sk, SOCK_TIMESTAMP);
        ts = ktime_to_timespec64(sock_read_timestamp(sk));
        if (ts.tv_sec == -1)
                return -ENOENT;
        if (ts.tv_sec == 0) {
                ktime_t kt = ktime_get_real();
                sock_write_timestamp(sk, kt);
                ts = ktime_to_timespec64(kt);
        }

        if (timeval)
                ts.tv_nsec /= 1000;

#ifdef CONFIG_COMPAT_32BIT_TIME
        if (time32)
                return put_old_timespec32(&ts, userstamp);
#endif
#ifdef CONFIG_SPARC64
        /* beware of padding in sparc64 timeval */
        if (timeval && !in_compat_syscall()) {
                struct __kernel_old_timeval __user tv = {
                        .tv_sec = ts.tv_sec,
                        .tv_usec = ts.tv_nsec,
                };
                if (copy_to_user(userstamp, &tv, sizeof(tv)))
                        return -EFAULT;
                return 0;
        }
#endif
        return put_timespec64(&ts, userstamp);
}
EXPORT_SYMBOL(sock_gettstamp);

void sock_enable_timestamp(struct sock *sk, enum sock_flags 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 (sock_needs_netstamp(sk) &&
                    !(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;
        int copied, err;

        err = -EAGAIN;
        skb = sock_dequeue_err_skb(sk);
        if (skb == NULL)
                goto out;

        copied = skb->len;
        if (copied > len) {
                msg->msg_flags |= MSG_TRUNC;
                copied = len;
        }
        err = skb_copy_datagram_msg(skb, 0, msg, 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;

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);

int sock_common_recvmsg(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(sk, msg, size, flags, &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,
                           sockptr_t optval, unsigned int optlen)
{
        struct sock *sk = sock->sk;

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

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

        /*
         * Observation: when sk_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);

void sk_get_meminfo(const struct sock *sk, u32 *mem)
{
        memset(mem, 0, sizeof(*mem) * SK_MEMINFO_VARS);

        mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
        mem[SK_MEMINFO_RCVBUF] = READ_ONCE(sk->sk_rcvbuf);
        mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
        mem[SK_MEMINFO_SNDBUF] = READ_ONCE(sk->sk_sndbuf);
        mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
        mem[SK_MEMINFO_WMEM_QUEUED] = READ_ONCE(sk->sk_wmem_queued);
        mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
        mem[SK_MEMINFO_BACKLOG] = READ_ONCE(sk->sk_backlog.len);
        mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops);
}

#ifdef CONFIG_PROC_FS
static DECLARE_BITMAP(proto_inuse_idx, PROTO_INUSE_NR);

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.prot_inuse, cpu)->val[idx];

        return res >= 0 ? res : 0;
}
EXPORT_SYMBOL_GPL(sock_prot_inuse_get);

int sock_inuse_get(struct net *net)
{
        int cpu, res = 0;

        for_each_possible_cpu(cpu)
                res += per_cpu_ptr(net->core.prot_inuse, cpu)->all;

        return res;
}

EXPORT_SYMBOL_GPL(sock_inuse_get);

static int __net_init sock_inuse_init_net(struct net *net)
{
        net->core.prot_inuse = alloc_percpu(struct prot_inuse);
        if (net->core.prot_inuse == NULL)
                return -ENOMEM;
        return 0;
}

static void __net_exit sock_inuse_exit_net(struct net *net)
{
        free_percpu(net->core.prot_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);

static int 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 -ENOSPC;
        }

        set_bit(prot->inuse_idx, proto_inuse_idx);
        return 0;
}

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 int assign_proto_idx(struct proto *prot)
{
        return 0;
}

static inline void release_proto_idx(struct proto *prot)
{
}

#endif

static void tw_prot_cleanup(struct timewait_sock_ops *twsk_prot)
{
        if (!twsk_prot)
                return;
        kfree(twsk_prot->twsk_slab_name);
        twsk_prot->twsk_slab_name = NULL;
        kmem_cache_destroy(twsk_prot->twsk_slab);
        twsk_prot->twsk_slab = NULL;
}

static int tw_prot_init(const struct proto *prot)
{
        struct timewait_sock_ops *twsk_prot = prot->twsk_prot;

        if (!twsk_prot)
                return 0;

        twsk_prot->twsk_slab_name = kasprintf(GFP_KERNEL, "tw_sock_%s",
                                              prot->name);
        if (!twsk_prot->twsk_slab_name)
                return -ENOMEM;

        twsk_prot->twsk_slab =
                kmem_cache_create(twsk_prot->twsk_slab_name,
                                  twsk_prot->twsk_obj_size, 0,
                                  SLAB_ACCOUNT | prot->slab_flags,
                                  NULL);
        if (!twsk_prot->twsk_slab) {
                pr_crit("%s: Can't create timewait sock SLAB cache!\n",
                        prot->name);
                return -ENOMEM;
        }

        return 0;
}

static void req_prot_cleanup(struct request_sock_ops *rsk_prot)
{
        if (!rsk_prot)
                return;
        kfree(rsk_prot->slab_name);
        rsk_prot->slab_name = NULL;
        kmem_cache_destroy(rsk_prot->slab);
        rsk_prot->slab = NULL;
}

static int req_prot_init(const struct proto *prot)
{
        struct request_sock_ops *rsk_prot = prot->rsk_prot;

        if (!rsk_prot)
                return 0;

        rsk_prot->slab_name = kasprintf(GFP_KERNEL, "request_sock_%s",
                                        prot->name);
        if (!rsk_prot->slab_name)
                return -ENOMEM;

        rsk_prot->slab = kmem_cache_create(rsk_prot->slab_name,
                                           rsk_prot->obj_size, 0,
                                           SLAB_ACCOUNT | prot->slab_flags,
                                           NULL);

        if (!rsk_prot->slab) {
                pr_crit("%s: Can't create request sock SLAB cache!\n",
                        prot->name);
                return -ENOMEM;
        }
        return 0;
}

int proto_register(struct proto *prot, int alloc_slab)
{
        int ret = -ENOBUFS;

        if (prot->memory_allocated && !prot->sysctl_mem) {
                pr_err("%s: missing sysctl_mem\n", prot->name);
                return -EINVAL;
        }
        if (alloc_slab) {
                prot->slab = kmem_cache_create_usercopy(prot->name,
                                        prot->obj_size, 0,
                                        SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT |
                                        prot->slab_flags,
                                        prot->useroffset, prot->usersize,
                                        NULL);

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

                if (req_prot_init(prot))
                        goto out_free_request_sock_slab;

                if (tw_prot_init(prot))
                        goto out_free_timewait_sock_slab;
        }

        mutex_lock(&proto_list_mutex);
        ret = assign_proto_idx(prot);
        if (ret) {
                mutex_unlock(&proto_list_mutex);
                goto out_free_timewait_sock_slab;
        }
        list_add(&prot->node, &proto_list);
        mutex_unlock(&proto_list_mutex);
        return ret;

out_free_timewait_sock_slab:
        if (alloc_slab)
                tw_prot_cleanup(prot->twsk_prot);
out_free_request_sock_slab:
        if (alloc_slab) {
                req_prot_cleanup(prot->rsk_prot);

                kmem_cache_destroy(prot->slab);
                prot->slab = NULL;
        }
out:
        return ret;
}
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);

        kmem_cache_destroy(prot->slab);
        prot->slab = NULL;

        req_prot_cleanup(prot->rsk_prot);
        tw_prot_cleanup(prot->twsk_prot);
}
EXPORT_SYMBOL(proto_unregister);

int sock_load_diag_module(int family, int protocol)
{
        if (!protocol) {
                if (!sock_is_registered(family))
                        return -ENOENT;

                return request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
                                      NETLINK_SOCK_DIAG, family);
        }

#ifdef CONFIG_INET
        if (family == AF_INET &&
            protocol != IPPROTO_RAW &&
            protocol < MAX_INET_PROTOS &&
            !rcu_access_pointer(inet_protos[protocol]))
                return -ENOENT;
#endif

        return request_module("net-pf-%d-proto-%d-type-%d-%d", PF_NETLINK,
                              NETLINK_SOCK_DIAG, family, protocol);
}
EXPORT_SYMBOL(sock_load_diag_module);

#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 const 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 __net_init int proto_init_net(struct net *net)
{
        if (!proc_create_net("protocols", 0444, net->proc_net, &proto_seq_ops,
                        sizeof(struct seq_net_private)))
                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);