text: /*
   *	ip6_flowlabel.c		IPv6 flowlabel manager.
   *
   *	This program is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU General Public License
   *      as published by the Free Software Foundation; either version
   *      2 of the License, or (at your option) any later version.
   *
   *	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/if_arp.h>
  #include <linux/in6.h>
  #include <linux/route.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/slab.h>
  #include <linux/export.h>
  
  #include <net/net_namespace.h>
  #include <net/sock.h>
  
  #include <net/ipv6.h>
  #include <net/ndisc.h>
  #include <net/protocol.h>
  #include <net/ip6_route.h>
  #include <net/addrconf.h>
  #include <net/rawv6.h>
  #include <net/icmp.h>
  #include <net/transp_v6.h>
  
  #include <asm/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	60	/* 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 *fl_ht[FL_HASH_MASK+1];
  
  static void ip6_fl_gc(unsigned long dummy);
  static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
  
  /* FL hash table lock: it protects only of GC */
  
  static DEFINE_RWLOCK(ip6_fl_lock);
  
  /* Big socket sock */
  
  static DEFINE_RWLOCK(ip6_sk_fl_lock);
  
  
  static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
  {
  	struct ip6_flowlabel *fl;
  
  	for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) {
  		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;
  
  	read_lock_bh(&ip6_fl_lock);
  	fl = __fl_lookup(net, label);
  	if (fl)
  		atomic_inc(&fl->users);
  	read_unlock_bh(&ip6_fl_lock);
  	return fl;
  }
  
  
  static void fl_free(struct ip6_flowlabel *fl)
  {
  	if (fl) {
  		release_net(fl->fl_net);
  		kfree(fl->opt);
  	}
  	kfree(fl);
  }
  
  static void fl_release(struct ip6_flowlabel *fl)
  {
  	write_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);
  	}
  	write_unlock_bh(&ip6_fl_lock);
  }
  
  static void ip6_fl_gc(unsigned long dummy)
  {
  	int i;
  	unsigned long now = jiffies;
  	unsigned long sched = 0;
  
  	write_lock(&ip6_fl_lock);
  
  	for (i=0; i<=FL_HASH_MASK; i++) {
  		struct ip6_flowlabel *fl, **flp;
  		flp = &fl_ht[i];
  		while ((fl=*flp) != 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);
  	}
  	write_unlock(&ip6_fl_lock);
  }
  
  static void __net_exit ip6_fl_purge(struct net *net)
  {
  	int i;
  
  	write_lock(&ip6_fl_lock);
  	for (i = 0; i <= FL_HASH_MASK; i++) {
  		struct ip6_flowlabel *fl, **flp;
  		flp = &fl_ht[i];
  		while ((fl = *flp) != 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;
  		}
  	}
  	write_unlock(&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;
  
  	write_lock_bh(&ip6_fl_lock);
  	if (label == 0) {
  		for (;;) {
  			fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
  			if (fl->label) {
  				lfl = __fl_lookup(net, fl->label);
  				if (lfl == NULL)
  					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 != NULL) {
  			atomic_inc(&lfl->users);
  			write_unlock_bh(&ip6_fl_lock);
  			return lfl;
  		}
  	}
  
  	fl->lastuse = jiffies;
  	fl->next = fl_ht[FL_HASH(fl->label)];
  	fl_ht[FL_HASH(fl->label)] = fl;
  	atomic_inc(&fl_size);
  	write_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;
  
  	read_lock_bh(&ip6_sk_fl_lock);
  	for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
  		struct ip6_flowlabel *fl = sfl->fl;
  		if (fl->label == label) {
  			fl->lastuse = jiffies;
  			atomic_inc(&fl->users);
  			read_unlock_bh(&ip6_sk_fl_lock);
  			return fl;
  		}
  	}
  	read_unlock_bh(&ip6_sk_fl_lock);
  	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;
  
  	while ((sfl = np->ipv6_fl_list) != NULL) {
  		np->ipv6_fl_list = sfl->next;
  		fl_release(sfl->fl);
  		kfree(sfl);
  	}
  }
  
  /* 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 == NULL || fopt->opt_flen == 0)
  		return fl_opt;
  
  	if (fl_opt != NULL) {
  		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;
  	return opt_space;
  }
  
  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;
  	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;
  	return 0;
  }
  
  static struct ip6_flowlabel *
  fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
  	  char __user *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 == NULL)
  		goto done;
  
  	if (olen > 0) {
  		struct msghdr msg;
  		struct flowi6 flowi6;
  		int junk;
  
  		err = -ENOMEM;
  		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
  		if (fl->opt == NULL)
  			goto done;
  
  		memset(fl->opt, 0, sizeof(*fl->opt));
  		fl->opt->tot_len = sizeof(*fl->opt) + olen;
  		err = -EFAULT;
  		if (copy_from_user(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));
  
  		err = datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt, &junk,
  					&junk, &junk);
  		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 = hold_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 = current->pid;
  		break;
  	case IPV6_FL_S_USER:
  		fl->owner = current_euid();
  		break;
  	default:
  		err = -EINVAL;
  		goto done;
  	}
  	return fl;
  
  done:
  	fl_free(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;
  
  	for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
  		count++;
  
  	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 int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
  {
  	if (h1 == h2)
  		return 0;
  	if (h1 == NULL || h2 == NULL)
  		return 1;
  	if (h1->hdrlen != h2->hdrlen)
  		return 1;
  	return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
  }
  
  static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
  {
  	if (o1 == o2)
  		return 0;
  	if (o1 == NULL || o2 == NULL)
  		return 1;
  	if (o1->opt_nflen != o2->opt_nflen)
  		return 1;
  	if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
  		return 1;
  	if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
  		return 1;
  	if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
  		return 1;
  	return 0;
  }
  
  static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
  		struct ip6_flowlabel *fl)
  {
  	write_lock_bh(&ip6_sk_fl_lock);
  	sfl->fl = fl;
  	sfl->next = np->ipv6_fl_list;
  	np->ipv6_fl_list = sfl;
  	write_unlock_bh(&ip6_sk_fl_lock);
  }
  
  int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
  {
  	int uninitialized_var(err);
  	struct net *net = sock_net(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct in6_flowlabel_req freq;
  	struct ipv6_fl_socklist *sfl1=NULL;
  	struct ipv6_fl_socklist *sfl, **sflp;
  	struct ip6_flowlabel *fl, *fl1 = NULL;
  
  
  	if (optlen < sizeof(freq))
  		return -EINVAL;
  
  	if (copy_from_user(&freq, optval, sizeof(freq)))
  		return -EFAULT;
  
  	switch (freq.flr_action) {
  	case IPV6_FL_A_PUT:
  		write_lock_bh(&ip6_sk_fl_lock);
  		for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
  			if (sfl->fl->label == freq.flr_label) {
  				if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
  					np->flow_label &= ~IPV6_FLOWLABEL_MASK;
  				*sflp = sfl->next;
  				write_unlock_bh(&ip6_sk_fl_lock);
  				fl_release(sfl->fl);
  				kfree(sfl);
  				return 0;
  			}
  		}
  		write_unlock_bh(&ip6_sk_fl_lock);
  		return -ESRCH;
  
  	case IPV6_FL_A_RENEW:
  		read_lock_bh(&ip6_sk_fl_lock);
  		for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
  			if (sfl->fl->label == freq.flr_label) {
  				err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
  				read_unlock_bh(&ip6_sk_fl_lock);
  				return err;
  			}
  		}
  		read_unlock_bh(&ip6_sk_fl_lock);
  
  		if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
  			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;
  
  	case IPV6_FL_A_GET:
  		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
  			return -EINVAL;
  
  		fl = fl_create(net, sk, &freq, optval, optlen, &err);
  		if (fl == NULL)
  			return err;
  		sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
  
  		if (freq.flr_label) {
  			err = -EEXIST;
  			read_lock_bh(&ip6_sk_fl_lock);
  			for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
  				if (sfl->fl->label == freq.flr_label) {
  					if (freq.flr_flags&IPV6_FL_F_EXCL) {
  						read_unlock_bh(&ip6_sk_fl_lock);
  						goto done;
  					}
  					fl1 = sfl->fl;
  					atomic_inc(&fl1->users);
  					break;
  				}
  			}
  			read_unlock_bh(&ip6_sk_fl_lock);
  
  			if (fl1 == NULL)
  				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->owner != fl->owner)
  					goto release;
  
  				err = -EINVAL;
  				if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
  				    ipv6_opt_cmp(fl1->opt, fl->opt))
  					goto release;
  
  				err = -ENOMEM;
  				if (sfl1 == NULL)
  					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 == NULL || (err = mem_check(sk)) != 0)
  			goto done;
  
  		fl1 = fl_intern(net, fl, freq.flr_label);
  		if (fl1 != NULL)
  			goto recheck;
  
  		if (!freq.flr_label) {
  			if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
  					 &fl->label, sizeof(fl->label))) {
  				/* Intentionally ignore fault. */
  			}
  		}
  
  		fl_link(np, sfl1, fl);
  		return 0;
  
  	default:
  		return -EINVAL;
  	}
  
  done:
  	fl_free(fl);
  	kfree(sfl1);
  	return err;
  }
  
  #ifdef CONFIG_PROC_FS
  
  struct ip6fl_iter_state {
  	struct seq_net_private p;
  	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) {
  		fl = fl_ht[state->bucket];
  
  		while (fl && !net_eq(fl->fl_net, net))
  			fl = fl->next;
  		if (fl)
  			break;
  	}
  	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);
  
  	fl = fl->next;
  try_again:
  	while (fl && !net_eq(fl->fl_net, net))
  		fl = fl->next;
  
  	while (!fl) {
  		if (++state->bucket <= FL_HASH_MASK) {
  			fl = fl_ht[state->bucket];
  			goto try_again;
  		} else
  			break;
  	}
  	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(ip6_fl_lock)
  {
  	read_lock_bh(&ip6_fl_lock);
  	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(ip6_fl_lock)
  {
  	read_unlock_bh(&ip6_fl_lock);
  }
  
  static int ip6fl_seq_show(struct seq_file *seq, void *v)
  {
  	if (v == SEQ_START_TOKEN)
  		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
  			   "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\n",
  			   (unsigned)ntohl(fl->label),
  			   fl->share,
  			   (unsigned)fl->owner,
  			   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 ip6fl_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &ip6fl_seq_ops,
  			    sizeof(struct ip6fl_iter_state));
  }
  
  static const struct file_operations ip6fl_seq_fops = {
  	.owner		=	THIS_MODULE,
  	.open		=	ip6fl_seq_open,
  	.read		=	seq_read,
  	.llseek		=	seq_lseek,
  	.release	=	seq_release_net,
  };
  
  static int __net_init ip6_flowlabel_proc_init(struct net *net)
  {
  	if (!proc_net_fops_create(net, "ip6_flowlabel",
  				  S_IRUGO, &ip6fl_seq_fops))
  		return -ENOMEM;
  	return 0;
  }
  
  static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
  {
  	proc_net_remove(net, "ip6_flowlabel");
  }
  #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)
  {
  	del_timer(&ip6_fl_gc_timer);
  	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
  }
  