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

  /*
   *	ip6_flowlabel.c		IPv6 flowlabel manager.
   *

   *	Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   */

  #include <linux/capability.h>

  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>

  #include <linux/in6.h>

  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>

  #include <linux/slab.h>

  #include <linux/export.h>

  #include <linux/pid_namespace.h>

  #include <linux/jump_label_ratelimit.h>

  #include <net/net_namespace.h>

  #include <net/sock.h>
  
  #include <net/ipv6.h>

  #include <net/rawv6.h>

  #include <net/transp_v6.h>

  #include <linux/uaccess.h>

  
  #define FL_MIN_LINGER	6	/* Minimal linger. It is set to 6sec specified
  				   in old IPv6 RFC. Well, it was reasonable value.
  				 */

  #define FL_MAX_LINGER	150	/* Maximal linger timeout */

  
  /* FL hash table */
  
  #define FL_MAX_PER_SOCK	32
  #define FL_MAX_SIZE	4096
  #define FL_HASH_MASK	255
  #define FL_HASH(l)	(ntohl(l)&FL_HASH_MASK)
  
  static atomic_t fl_size = ATOMIC_INIT(0);

  static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];

  static void ip6_fl_gc(struct timer_list *unused);

  static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc);

  
  /* FL hash table lock: it protects only of GC */

  static DEFINE_SPINLOCK(ip6_fl_lock);

  
  /* Big socket sock */

  static DEFINE_SPINLOCK(ip6_sk_fl_lock);

  DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
  EXPORT_SYMBOL(ipv6_flowlabel_exclusive);

  #define for_each_fl_rcu(hash, fl)				\

  	for (fl = rcu_dereference_bh(fl_ht[(hash)]);		\

  	     fl != NULL;					\

  	     fl = rcu_dereference_bh(fl->next))

  #define for_each_fl_continue_rcu(fl)				\

  	for (fl = rcu_dereference_bh(fl->next);			\

  	     fl != NULL;					\

  	     fl = rcu_dereference_bh(fl->next))

  #define for_each_sk_fl_rcu(np, sfl)				\
  	for (sfl = rcu_dereference_bh(np->ipv6_fl_list);	\
  	     sfl != NULL;					\
  	     sfl = rcu_dereference_bh(sfl->next))

  static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)

  {
  	struct ip6_flowlabel *fl;

  	for_each_fl_rcu(FL_HASH(label), fl) {

  		if (fl->label == label && net_eq(fl->fl_net, net))

  			return fl;
  	}
  	return NULL;
  }

  static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)

  {
  	struct ip6_flowlabel *fl;

  	rcu_read_lock_bh();

  	fl = __fl_lookup(net, label);

  	if (fl && !atomic_inc_not_zero(&fl->users))
  		fl = NULL;
  	rcu_read_unlock_bh();

  	return fl;
  }

  static bool fl_shared_exclusive(struct ip6_flowlabel *fl)
  {
  	return fl->share == IPV6_FL_S_EXCL ||
  	       fl->share == IPV6_FL_S_PROCESS ||
  	       fl->share == IPV6_FL_S_USER;
  }

  static void fl_free_rcu(struct rcu_head *head)
  {
  	struct ip6_flowlabel *fl = container_of(head, struct ip6_flowlabel, rcu);
  
  	if (fl->share == IPV6_FL_S_PROCESS)
  		put_pid(fl->owner.pid);
  	kfree(fl->opt);
  	kfree(fl);
  }

  
  static void fl_free(struct ip6_flowlabel *fl)
  {

  	if (!fl)
  		return;
  
  	if (fl_shared_exclusive(fl) || fl->opt)
  		static_branch_slow_dec_deferred(&ipv6_flowlabel_exclusive);
  
  	call_rcu(&fl->rcu, fl_free_rcu);

  }
  
  static void fl_release(struct ip6_flowlabel *fl)
  {

  	spin_lock_bh(&ip6_fl_lock);

  
  	fl->lastuse = jiffies;
  	if (atomic_dec_and_test(&fl->users)) {
  		unsigned long ttd = fl->lastuse + fl->linger;
  		if (time_after(ttd, fl->expires))
  			fl->expires = ttd;
  		ttd = fl->expires;
  		if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
  			struct ipv6_txoptions *opt = fl->opt;
  			fl->opt = NULL;
  			kfree(opt);
  		}
  		if (!timer_pending(&ip6_fl_gc_timer) ||
  		    time_after(ip6_fl_gc_timer.expires, ttd))
  			mod_timer(&ip6_fl_gc_timer, ttd);
  	}

  	spin_unlock_bh(&ip6_fl_lock);

  }

  static void ip6_fl_gc(struct timer_list *unused)

  {
  	int i;
  	unsigned long now = jiffies;
  	unsigned long sched = 0;

  	spin_lock(&ip6_fl_lock);

  	for (i = 0; i <= FL_HASH_MASK; i++) {

  		struct ip6_flowlabel *fl;
  		struct ip6_flowlabel __rcu **flp;

  		flp = &fl_ht[i];

  		while ((fl = rcu_dereference_protected(*flp,
  						       lockdep_is_held(&ip6_fl_lock))) != NULL) {

  			if (atomic_read(&fl->users) == 0) {
  				unsigned long ttd = fl->lastuse + fl->linger;
  				if (time_after(ttd, fl->expires))
  					fl->expires = ttd;
  				ttd = fl->expires;
  				if (time_after_eq(now, ttd)) {
  					*flp = fl->next;
  					fl_free(fl);
  					atomic_dec(&fl_size);
  					continue;
  				}
  				if (!sched || time_before(ttd, sched))
  					sched = ttd;
  			}
  			flp = &fl->next;
  		}
  	}
  	if (!sched && atomic_read(&fl_size))
  		sched = now + FL_MAX_LINGER;
  	if (sched) {

  		mod_timer(&ip6_fl_gc_timer, sched);

  	}

  	spin_unlock(&ip6_fl_lock);

  }

  static void __net_exit ip6_fl_purge(struct net *net)

  {
  	int i;

  	spin_lock_bh(&ip6_fl_lock);

  	for (i = 0; i <= FL_HASH_MASK; i++) {

  		struct ip6_flowlabel *fl;
  		struct ip6_flowlabel __rcu **flp;

  		flp = &fl_ht[i];

  		while ((fl = rcu_dereference_protected(*flp,
  						       lockdep_is_held(&ip6_fl_lock))) != NULL) {

  			if (net_eq(fl->fl_net, net) &&
  			    atomic_read(&fl->users) == 0) {

  				*flp = fl->next;
  				fl_free(fl);
  				atomic_dec(&fl_size);
  				continue;
  			}
  			flp = &fl->next;
  		}
  	}

  	spin_unlock_bh(&ip6_fl_lock);

  }
  
  static struct ip6_flowlabel *fl_intern(struct net *net,
  				       struct ip6_flowlabel *fl, __be32 label)

  {

  	struct ip6_flowlabel *lfl;

  	fl->label = label & IPV6_FLOWLABEL_MASK;

  	spin_lock_bh(&ip6_fl_lock);

  	if (label == 0) {
  		for (;;) {

  			fl->label = htonl(prandom_u32())&IPV6_FLOWLABEL_MASK;

  			if (fl->label) {

  				lfl = __fl_lookup(net, fl->label);

  				if (!lfl)

  					break;
  			}
  		}

  	} else {
  		/*
  		 * we dropper the ip6_fl_lock, so this entry could reappear
  		 * and we need to recheck with it.
  		 *
  		 * OTOH no need to search the active socket first, like it is
  		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
  		 * with the same label can only appear on another sock
  		 */

  		lfl = __fl_lookup(net, fl->label);

  		if (lfl) {

  			atomic_inc(&lfl->users);

  			spin_unlock_bh(&ip6_fl_lock);

  			return lfl;
  		}

  	}
  
  	fl->lastuse = jiffies;
  	fl->next = fl_ht[FL_HASH(fl->label)];

  	rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);

  	atomic_inc(&fl_size);

  	spin_unlock_bh(&ip6_fl_lock);

  	return NULL;

  }
  
  
  
  /* Socket flowlabel lists */

  struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)

  {
  	struct ipv6_fl_socklist *sfl;
  	struct ipv6_pinfo *np = inet6_sk(sk);
  
  	label &= IPV6_FLOWLABEL_MASK;

  	rcu_read_lock_bh();
  	for_each_sk_fl_rcu(np, sfl) {

  		struct ip6_flowlabel *fl = sfl->fl;

  
  		if (fl->label == label && atomic_inc_not_zero(&fl->users)) {

  			fl->lastuse = jiffies;

  			rcu_read_unlock_bh();

  			return fl;
  		}
  	}

  	rcu_read_unlock_bh();

  	return NULL;
  }

  EXPORT_SYMBOL_GPL(__fl6_sock_lookup);

  void fl6_free_socklist(struct sock *sk)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct ipv6_fl_socklist *sfl;

  	if (!rcu_access_pointer(np->ipv6_fl_list))

  		return;

  	spin_lock_bh(&ip6_sk_fl_lock);
  	while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
  						lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
  		np->ipv6_fl_list = sfl->next;
  		spin_unlock_bh(&ip6_sk_fl_lock);

  		fl_release(sfl->fl);

  		kfree_rcu(sfl, rcu);
  
  		spin_lock_bh(&ip6_sk_fl_lock);

  	}

  	spin_unlock_bh(&ip6_sk_fl_lock);

  }
  
  /* Service routines */
  
  
  /*
     It is the only difficult place. flowlabel enforces equal headers
     before and including routing header, however user may supply options
     following rthdr.
   */

  struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
  					 struct ip6_flowlabel *fl,
  					 struct ipv6_txoptions *fopt)

  {

  	struct ipv6_txoptions *fl_opt = fl->opt;

  	if (!fopt || fopt->opt_flen == 0)

  		return fl_opt;

  	if (fl_opt) {

  		opt_space->hopopt = fl_opt->hopopt;

  		opt_space->dst0opt = fl_opt->dst0opt;

  		opt_space->srcrt = fl_opt->srcrt;
  		opt_space->opt_nflen = fl_opt->opt_nflen;
  	} else {
  		if (fopt->opt_nflen == 0)
  			return fopt;
  		opt_space->hopopt = NULL;
  		opt_space->dst0opt = NULL;
  		opt_space->srcrt = NULL;
  		opt_space->opt_nflen = 0;
  	}
  	opt_space->dst1opt = fopt->dst1opt;

  	opt_space->opt_flen = fopt->opt_flen;

  	opt_space->tot_len = fopt->tot_len;

  	return opt_space;
  }

  EXPORT_SYMBOL_GPL(fl6_merge_options);

  
  static unsigned long check_linger(unsigned long ttl)
  {
  	if (ttl < FL_MIN_LINGER)
  		return FL_MIN_LINGER*HZ;
  	if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
  		return 0;
  	return ttl*HZ;
  }
  
  static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
  {
  	linger = check_linger(linger);
  	if (!linger)
  		return -EPERM;
  	expires = check_linger(expires);
  	if (!expires)
  		return -EPERM;

  
  	spin_lock_bh(&ip6_fl_lock);

  	fl->lastuse = jiffies;
  	if (time_before(fl->linger, linger))
  		fl->linger = linger;
  	if (time_before(expires, fl->linger))
  		expires = fl->linger;
  	if (time_before(fl->expires, fl->lastuse + expires))
  		fl->expires = fl->lastuse + expires;

  	spin_unlock_bh(&ip6_fl_lock);

  	return 0;
  }
  
  static struct ip6_flowlabel *

  fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,

  	  sockptr_t optval, int optlen, int *err_p)

  {

  	struct ip6_flowlabel *fl = NULL;

  	int olen;
  	int addr_type;
  	int err;

  	olen = optlen - CMSG_ALIGN(sizeof(*freq));
  	err = -EINVAL;
  	if (olen > 64 * 1024)
  		goto done;

  	err = -ENOMEM;

  	fl = kzalloc(sizeof(*fl), GFP_KERNEL);

  	if (!fl)

  		goto done;

  	if (olen > 0) {
  		struct msghdr msg;

  		struct flowi6 flowi6;

  		struct ipcm6_cookie ipc6;

  
  		err = -ENOMEM;
  		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);

  		if (!fl->opt)

  			goto done;
  
  		memset(fl->opt, 0, sizeof(*fl->opt));
  		fl->opt->tot_len = sizeof(*fl->opt) + olen;
  		err = -EFAULT;

  		if (copy_from_sockptr_offset(fl->opt + 1, optval,
  				CMSG_ALIGN(sizeof(*freq)), olen))

  			goto done;
  
  		msg.msg_controllen = olen;

  		msg.msg_control = (void *)(fl->opt+1);

  		memset(&flowi6, 0, sizeof(flowi6));

  		ipc6.opt = fl->opt;

  		err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6);

  		if (err)
  			goto done;
  		err = -EINVAL;
  		if (fl->opt->opt_flen)
  			goto done;
  		if (fl->opt->opt_nflen == 0) {
  			kfree(fl->opt);
  			fl->opt = NULL;
  		}
  	}

  	fl->fl_net = net;

  	fl->expires = jiffies;
  	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
  	if (err)
  		goto done;
  	fl->share = freq->flr_share;
  	addr_type = ipv6_addr_type(&freq->flr_dst);

  	if ((addr_type & IPV6_ADDR_MAPPED) ||
  	    addr_type == IPV6_ADDR_ANY) {

  		err = -EINVAL;

  		goto done;

  	}

  	fl->dst = freq->flr_dst;

  	atomic_set(&fl->users, 1);
  	switch (fl->share) {
  	case IPV6_FL_S_EXCL:
  	case IPV6_FL_S_ANY:
  		break;
  	case IPV6_FL_S_PROCESS:

  		fl->owner.pid = get_task_pid(current, PIDTYPE_PID);

  		break;
  	case IPV6_FL_S_USER:

  		fl->owner.uid = current_euid();

  		break;
  	default:
  		err = -EINVAL;
  		goto done;
  	}

  	if (fl_shared_exclusive(fl) || fl->opt)
  		static_branch_deferred_inc(&ipv6_flowlabel_exclusive);

  	return fl;
  
  done:

  	if (fl) {
  		kfree(fl->opt);
  		kfree(fl);
  	}

  	*err_p = err;
  	return NULL;
  }
  
  static int mem_check(struct sock *sk)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct ipv6_fl_socklist *sfl;
  	int room = FL_MAX_SIZE - atomic_read(&fl_size);
  	int count = 0;
  
  	if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
  		return 0;

  	rcu_read_lock_bh();

  	for_each_sk_fl_rcu(np, sfl)

  		count++;

  	rcu_read_unlock_bh();

  
  	if (room <= 0 ||
  	    ((count >= FL_MAX_PER_SOCK ||

  	      (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
  	     !capable(CAP_NET_ADMIN)))

  		return -ENOBUFS;
  
  	return 0;
  }

  static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
  		struct ip6_flowlabel *fl)
  {

  	spin_lock_bh(&ip6_sk_fl_lock);

  	sfl->fl = fl;
  	sfl->next = np->ipv6_fl_list;

  	rcu_assign_pointer(np->ipv6_fl_list, sfl);
  	spin_unlock_bh(&ip6_sk_fl_lock);

  }

  int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
  			   int flags)

  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct ipv6_fl_socklist *sfl;

  	if (flags & IPV6_FL_F_REMOTE) {
  		freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
  		return 0;
  	}

  	if (np->repflow) {
  		freq->flr_label = np->flow_label;
  		return 0;
  	}

  	rcu_read_lock_bh();
  
  	for_each_sk_fl_rcu(np, sfl) {
  		if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
  			spin_lock_bh(&ip6_fl_lock);
  			freq->flr_label = sfl->fl->label;
  			freq->flr_dst = sfl->fl->dst;
  			freq->flr_share = sfl->fl->share;
  			freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
  			freq->flr_linger = sfl->fl->linger / HZ;
  
  			spin_unlock_bh(&ip6_fl_lock);
  			rcu_read_unlock_bh();
  			return 0;
  		}
  	}
  	rcu_read_unlock_bh();
  
  	return -ENOENT;
  }

  #define socklist_dereference(__sflp) \
  	rcu_dereference_protected(__sflp, lockdep_is_held(&ip6_sk_fl_lock))
  
  static int ipv6_flowlabel_put(struct sock *sk, struct in6_flowlabel_req *freq)

  {

  	struct ipv6_pinfo *np = inet6_sk(sk);

  	struct ipv6_fl_socklist __rcu **sflp;

  	struct ipv6_fl_socklist *sfl;

  	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
  		if (sk->sk_protocol != IPPROTO_TCP)
  			return -ENOPROTOOPT;
  		if (!np->repflow)
  			return -ESRCH;
  		np->flow_label = 0;
  		np->repflow = 0;
  		return 0;
  	}

  	spin_lock_bh(&ip6_sk_fl_lock);
  	for (sflp = &np->ipv6_fl_list;
  	     (sfl = socklist_dereference(*sflp)) != NULL;
  	     sflp = &sfl->next) {
  		if (sfl->fl->label == freq->flr_label)
  			goto found;
  	}
  	spin_unlock_bh(&ip6_sk_fl_lock);
  	return -ESRCH;
  found:
  	if (freq->flr_label == (np->flow_label & IPV6_FLOWLABEL_MASK))
  		np->flow_label &= ~IPV6_FLOWLABEL_MASK;
  	*sflp = sfl->next;
  	spin_unlock_bh(&ip6_sk_fl_lock);
  	fl_release(sfl->fl);
  	kfree_rcu(sfl, rcu);
  	return 0;
  }

  static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct net *net = sock_net(sk);
  	struct ipv6_fl_socklist *sfl;
  	int err;

  	rcu_read_lock_bh();
  	for_each_sk_fl_rcu(np, sfl) {
  		if (sfl->fl->label == freq->flr_label) {
  			err = fl6_renew(sfl->fl, freq->flr_linger,
  					freq->flr_expires);
  			rcu_read_unlock_bh();
  			return err;

  		}

  	}
  	rcu_read_unlock_bh();

  	if (freq->flr_share == IPV6_FL_S_NONE &&
  	    ns_capable(net->user_ns, CAP_NET_ADMIN)) {
  		struct ip6_flowlabel *fl = fl_lookup(net, freq->flr_label);

  		if (fl) {
  			err = fl6_renew(fl, freq->flr_linger,
  					freq->flr_expires);
  			fl_release(fl);
  			return err;

  		}

  	}
  	return -ESRCH;
  }

  static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,

  		sockptr_t optval, int optlen)

  {
  	struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
  	struct ip6_flowlabel *fl, *fl1 = NULL;
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct net *net = sock_net(sk);

  	int err;

  	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
  		if (net->ipv6.sysctl.flowlabel_consistency) {
  			net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
  ");
  			return -EPERM;

  		}

  		if (sk->sk_protocol != IPPROTO_TCP)
  			return -ENOPROTOOPT;
  		np->repflow = 1;
  		return 0;
  	}

  	if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
  		return -EINVAL;
  	if (net->ipv6.sysctl.flowlabel_state_ranges &&
  	    (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
  		return -ERANGE;

  	fl = fl_create(net, sk, freq, optval, optlen, &err);
  	if (!fl)
  		return err;

  	sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
  
  	if (freq->flr_label) {
  		err = -EEXIST;
  		rcu_read_lock_bh();
  		for_each_sk_fl_rcu(np, sfl) {
  			if (sfl->fl->label == freq->flr_label) {
  				if (freq->flr_flags & IPV6_FL_F_EXCL) {
  					rcu_read_unlock_bh();
  					goto done;

  				}

  				fl1 = sfl->fl;
  				if (!atomic_inc_not_zero(&fl1->users))
  					fl1 = NULL;
  				break;

  			}

  		}
  		rcu_read_unlock_bh();

  		if (!fl1)
  			fl1 = fl_lookup(net, freq->flr_label);
  		if (fl1) {

  recheck:

  			err = -EEXIST;
  			if (freq->flr_flags&IPV6_FL_F_EXCL)
  				goto release;
  			err = -EPERM;
  			if (fl1->share == IPV6_FL_S_EXCL ||
  			    fl1->share != fl->share ||
  			    ((fl1->share == IPV6_FL_S_PROCESS) &&
  			     (fl1->owner.pid != fl->owner.pid)) ||
  			    ((fl1->share == IPV6_FL_S_USER) &&
  			     !uid_eq(fl1->owner.uid, fl->owner.uid)))
  				goto release;
  
  			err = -ENOMEM;
  			if (!sfl1)
  				goto release;
  			if (fl->linger > fl1->linger)
  				fl1->linger = fl->linger;
  			if ((long)(fl->expires - fl1->expires) > 0)
  				fl1->expires = fl->expires;
  			fl_link(np, sfl1, fl1);
  			fl_free(fl);
  			return 0;

  
  release:

  			fl_release(fl1);

  			goto done;

  		}
  	}
  	err = -ENOENT;
  	if (!(freq->flr_flags & IPV6_FL_F_CREATE))
  		goto done;

  	err = -ENOMEM;
  	if (!sfl1)
  		goto done;

  	err = mem_check(sk);
  	if (err != 0)
  		goto done;

  	fl1 = fl_intern(net, fl, freq->flr_label);
  	if (fl1)
  		goto recheck;

  	if (!freq->flr_label) {

  		size_t offset = offsetof(struct in6_flowlabel_req, flr_label);

  		if (copy_to_sockptr_offset(optval, offset, &fl->label,
  				sizeof(fl->label))) {

  			/* Intentionally ignore fault. */

  		}

  	}

  	fl_link(np, sfl1, fl);
  	return 0;

  done:
  	fl_free(fl);
  	kfree(sfl1);
  	return err;
  }

  int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)

  {
  	struct in6_flowlabel_req freq;
  
  	if (optlen < sizeof(freq))
  		return -EINVAL;

  	if (copy_from_sockptr(&freq, optval, sizeof(freq)))

  		return -EFAULT;
  
  	switch (freq.flr_action) {
  	case IPV6_FL_A_PUT:
  		return ipv6_flowlabel_put(sk, &freq);
  	case IPV6_FL_A_RENEW:
  		return ipv6_flowlabel_renew(sk, &freq);
  	case IPV6_FL_A_GET:
  		return ipv6_flowlabel_get(sk, &freq, optval, optlen);
  	default:
  		return -EINVAL;
  	}
  }

  #ifdef CONFIG_PROC_FS
  
  struct ip6fl_iter_state {

  	struct seq_net_private p;

  	struct pid_namespace *pid_ns;

  	int bucket;
  };
  
  #define ip6fl_seq_private(seq)	((struct ip6fl_iter_state *)(seq)->private)
  
  static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
  {
  	struct ip6_flowlabel *fl = NULL;
  	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);

  	struct net *net = seq_file_net(seq);

  
  	for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {

  		for_each_fl_rcu(state->bucket, fl) {
  			if (net_eq(fl->fl_net, net))
  				goto out;
  		}

  	}

  	fl = NULL;
  out:

  	return fl;
  }
  
  static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
  {
  	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);

  	struct net *net = seq_file_net(seq);

  	for_each_fl_continue_rcu(fl) {
  		if (net_eq(fl->fl_net, net))
  			goto out;
  	}

  try_again:

  	if (++state->bucket <= FL_HASH_MASK) {
  		for_each_fl_rcu(state->bucket, fl) {
  			if (net_eq(fl->fl_net, net))
  				goto out;
  		}
  		goto try_again;

  	}

  	fl = NULL;
  
  out:

  	return fl;
  }
  
  static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
  {
  	struct ip6_flowlabel *fl = ip6fl_get_first(seq);
  	if (fl)
  		while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
  			--pos;
  	return pos ? NULL : fl;
  }
  
  static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)

  	__acquires(RCU)

  {

  	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);

  	state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);

  	rcu_read_lock_bh();

  	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
  }
  
  static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct ip6_flowlabel *fl;
  
  	if (v == SEQ_START_TOKEN)
  		fl = ip6fl_get_first(seq);
  	else
  		fl = ip6fl_get_next(seq, v);
  	++*pos;
  	return fl;
  }
  
  static void ip6fl_seq_stop(struct seq_file *seq, void *v)

  	__releases(RCU)

  {

  	rcu_read_unlock_bh();

  }

  static int ip6fl_seq_show(struct seq_file *seq, void *v)

  {

  	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);

  	if (v == SEQ_START_TOKEN) {

  		seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt
  ");

  	} else {

  		struct ip6_flowlabel *fl = v;

  		seq_printf(seq,

  			   "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d
  ",

  			   (unsigned int)ntohl(fl->label),

  			   fl->share,

  			   ((fl->share == IPV6_FL_S_PROCESS) ?
  			    pid_nr_ns(fl->owner.pid, state->pid_ns) :
  			    ((fl->share == IPV6_FL_S_USER) ?
  			     from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
  			     0)),

  			   atomic_read(&fl->users),
  			   fl->linger/HZ,
  			   (long)(fl->expires - jiffies)/HZ,

  			   &fl->dst,

  			   fl->opt ? fl->opt->opt_nflen : 0);

  	}

  	return 0;
  }

  static const struct seq_operations ip6fl_seq_ops = {

  	.start	=	ip6fl_seq_start,
  	.next	=	ip6fl_seq_next,
  	.stop	=	ip6fl_seq_stop,
  	.show	=	ip6fl_seq_show,
  };

  static int __net_init ip6_flowlabel_proc_init(struct net *net)

  {

  	if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
  			&ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))

  		return -ENOMEM;
  	return 0;
  }

  static void __net_exit ip6_flowlabel_proc_fini(struct net *net)

  {

  	remove_proc_entry("ip6_flowlabel", net->proc_net);

  }
  #else
  static inline int ip6_flowlabel_proc_init(struct net *net)
  {
  	return 0;
  }
  static inline void ip6_flowlabel_proc_fini(struct net *net)
  {

  }

  #endif

  static void __net_exit ip6_flowlabel_net_exit(struct net *net)

  {
  	ip6_fl_purge(net);

  	ip6_flowlabel_proc_fini(net);

  }
  
  static struct pernet_operations ip6_flowlabel_net_ops = {

  	.init = ip6_flowlabel_proc_init,

  	.exit = ip6_flowlabel_net_exit,
  };

  int ip6_flowlabel_init(void)
  {

  	return register_pernet_subsys(&ip6_flowlabel_net_ops);

  }
  
  void ip6_flowlabel_cleanup(void)
  {

  	static_key_deferred_flush(&ipv6_flowlabel_exclusive);

  	del_timer(&ip6_fl_gc_timer);

  	unregister_pernet_subsys(&ip6_flowlabel_net_ops);

  }