Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 863 insertions, 0 deletions

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
new file mode 100644
index 000000000..f994f50e1
--- /dev/null
+++ b/net/ipv6/ip6_flowlabel.c
@@ -0,0 +1,863 @@
+/*
+ *	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/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 <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 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 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)
+		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,
+	  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)
+		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_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));
+
+		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;
+	}
+	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;
+
+	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;
+}
+
+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;
+	struct ipv6_fl_socklist __rcu **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:
+		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 = rcu_dereference_protected(*sflp,
+						      lockdep_is_held(&ip6_sk_fl_lock))) != 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;
+				spin_unlock_bh(&ip6_sk_fl_lock);
+				fl_release(sfl->fl);
+				kfree_rcu(sfl, rcu);
+				return 0;
+			}
+		}
+		spin_unlock_bh(&ip6_sk_fl_lock);
+		return -ESRCH;
+
+	case IPV6_FL_A_RENEW:
+		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)) {
+			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_flags & IPV6_FL_F_REFLECT) {
+			struct net *net = sock_net(sk);
+			if (net->ipv6.sysctl.flowlabel_consistency) {
+				net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
+				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) {
+			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;
+	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));
+
+	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\n");
+	} else {
+		struct ip6_flowlabel *fl = v;
+		seq_printf(seq,
+			   "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
+			   (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)
+{
+	del_timer(&ip6_fl_gc_timer);
+	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
+}