[NETNS][IPV6] flowlabels - make flowlabels per namespace

This patch introduces a new member, fl_net, in struct ip6_flowlabel.
This allows to create labels with the same value in different namespaces.
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -202,6 +202,7 @@ struct ip6_flowlabel
 	u32			owner;
 	unsigned long		lastuse;
 	unsigned long		expires;
+	struct net		*fl_net;
 };
 
 #define IPV6_FLOWINFO_MASK	__constant_htonl(0x0FFFFFFF)

net/ipv6/ip6_flowlabel.c

@@ -62,23 +62,23 @@ static DEFINE_RWLOCK(ip6_fl_lock);
 static DEFINE_RWLOCK(ip6_sk_fl_lock);
 
 
-static __inline__ struct ip6_flowlabel * __fl_lookup(__be32 label)
+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)
+		if (fl->label == label && fl->fl_net == net)
 			return fl;
 	}
 	return NULL;
 }
 
-static struct ip6_flowlabel * fl_lookup(__be32 label)
+static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
 {
 	struct ip6_flowlabel *fl;
 
 	read_lock_bh(&ip6_fl_lock);
-	fl = __fl_lookup(label);
+	fl = __fl_lookup(net, label);
 	if (fl)
 		atomic_inc(&fl->users);
 	read_unlock_bh(&ip6_fl_lock);
@@ -88,8 +88,10 @@ static struct ip6_flowlabel * fl_lookup(__be32 label)
 
 static void fl_free(struct ip6_flowlabel *fl)
 {
-	if (fl)
+	if (fl) {
+		release_net(fl->fl_net);
 		kfree(fl->opt);
+	}
 	kfree(fl);
 }
 
@@ -112,7 +114,6 @@ static void fl_release(struct ip6_flowlabel *fl)
 		    time_after(ip6_fl_gc_timer.expires, ttd))
 			mod_timer(&ip6_fl_gc_timer, ttd);
 	}
-
 	write_unlock_bh(&ip6_fl_lock);
 }
 
@@ -148,13 +149,34 @@ static void ip6_fl_gc(unsigned long dummy)
 	if (!sched && atomic_read(&fl_size))
 		sched = now + FL_MAX_LINGER;
 	if (sched) {
-		ip6_fl_gc_timer.expires = sched;
-		add_timer(&ip6_fl_gc_timer);
+		mod_timer(&ip6_fl_gc_timer, sched);
+	}
+	write_unlock(&ip6_fl_lock);
+}
+
+static void 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 (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 ip6_flowlabel *fl, __be32 label)
+static struct ip6_flowlabel *fl_intern(struct net *net,
+				       struct ip6_flowlabel *fl, __be32 label)
 {
 	struct ip6_flowlabel *lfl;
 
@@ -165,7 +187,7 @@ static struct ip6_flowlabel *fl_intern(struct ip6_flowlabel *fl, __be32 label)
 		for (;;) {
 			fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
 			if (fl->label) {
-				lfl = __fl_lookup(fl->label);
+				lfl = __fl_lookup(net, fl->label);
 				if (lfl == NULL)
 					break;
 			}
@@ -179,7 +201,7 @@ static struct ip6_flowlabel *fl_intern(struct ip6_flowlabel *fl, __be32 label)
 		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
 		 * with the same label can only appear on another sock
 		 */
-		lfl = __fl_lookup(fl->label);
+		lfl = __fl_lookup(net, fl->label);
 		if (lfl != NULL) {
 			atomic_inc(&lfl->users);
 			write_unlock_bh(&ip6_fl_lock);
@@ -298,7 +320,8 @@ static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned lo
 }
 
 static struct ip6_flowlabel *
-fl_create(struct in6_flowlabel_req *freq, char __user *optval, int optlen, int *err_p)
+fl_create(struct net *net, struct in6_flowlabel_req *freq, char __user *optval,
+	  int optlen, int *err_p)
 {
 	struct ip6_flowlabel *fl;
 	int olen;
@@ -343,6 +366,7 @@ fl_create(struct in6_flowlabel_req *freq, char __user *optval, int optlen, int *
 		}
 	}
 
+	fl->fl_net = hold_net(net);
 	fl->expires = jiffies;
 	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 	if (err)
@@ -441,6 +465,7 @@ static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 {
 	int 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;
@@ -483,7 +508,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 		read_unlock_bh(&ip6_sk_fl_lock);
 
 		if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
-			fl = fl_lookup(freq.flr_label);
+			fl = fl_lookup(net, freq.flr_label);
 			if (fl) {
 				err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 				fl_release(fl);
@@ -496,7 +521,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 			return -EINVAL;
 
-		fl = fl_create(&freq, optval, optlen, &err);
+		fl = fl_create(net, &freq, optval, optlen, &err);
 		if (fl == NULL)
 			return err;
 		sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
@@ -518,7 +543,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 			read_unlock_bh(&ip6_sk_fl_lock);
 
 			if (fl1 == NULL)
-				fl1 = fl_lookup(freq.flr_label);
+				fl1 = fl_lookup(net, freq.flr_label);
 			if (fl1) {
 recheck:
 				err = -EEXIST;
@@ -559,7 +584,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 		if (sfl1 == NULL || (err = mem_check(sk)) != 0)
 			goto done;
 
-		fl1 = fl_intern(fl, freq.flr_label);
+		fl1 = fl_intern(net, fl, freq.flr_label);
 		if (fl1 != NULL)
 			goto recheck;
 
@@ -717,13 +742,28 @@ static inline void ip6_flowlabel_proc_fini(struct net *net)
 }
 #endif
 
+static inline void ip6_flowlabel_net_exit(struct net *net)
+{
+	ip6_fl_purge(net);
+}
+
+static struct pernet_operations ip6_flowlabel_net_ops = {
+	.exit = ip6_flowlabel_net_exit,
+};
+
 int ip6_flowlabel_init(void)
 {
+	int err;
+
+	err = register_pernet_subsys(&ip6_flowlabel_net_ops);
+	if (err)
+		return err;
 	return ip6_flowlabel_proc_init(&init_net);
 }
 
 void ip6_flowlabel_cleanup(void)
 {
 	del_timer(&ip6_fl_gc_timer);
+	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 	ip6_flowlabel_proc_fini(&init_net);
 }