[NETNS][FRAGS]: Make the inet_frag_queue lookup work in namespaces.

Since fragment management code is consolidated, we cannot have the
pointer from inet_frag_queue to struct net, since we must know what
king of fragment this is.

So, I introduce the netns_frags structure. This one is currently
empty, but will be eventually filled with per-namespace
attributes. Each inet_frag_queue is tagged with this one.

The conntrack_reasm is not "netns-izated", so it has one static
netns_frags instance to keep working in init namespace.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/inet_frag.h

@@ -1,8 +1,12 @@
 #ifndef __NET_FRAG_H__
 #define __NET_FRAG_H__
 
+struct netns_frags {
+};
+
 struct inet_frag_queue {
 	struct hlist_node	list;
+	struct netns_frags	*net;
 	struct list_head	lru_list;   /* lru list member */
 	spinlock_t		lock;
 	atomic_t		refcnt;
@@ -55,8 +59,8 @@ void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
 void inet_frag_destroy(struct inet_frag_queue *q,
 				struct inet_frags *f, int *work);
 int inet_frag_evictor(struct inet_frags *f);
-struct inet_frag_queue *inet_frag_find(struct inet_frags *f, void *key,
-		unsigned int hash);
+struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
+		struct inet_frags *f, void *key, unsigned int hash);
 
 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
 {

include/net/netns/ipv4.h

@@ -5,6 +5,8 @@
 #ifndef __NETNS_IPV4_H__
 #define __NETNS_IPV4_H__
 
+#include <net/inet_frag.h>
+
 struct ctl_table_header;
 struct ipv4_devconf;
 struct fib_rules_ops;
@@ -22,5 +24,7 @@ struct netns_ipv4 {
 #endif
 	struct hlist_head	*fib_table_hash;
 	struct sock		*fibnl;
+
+	struct netns_frags	frags;
 };
 #endif

include/net/netns/ipv6.h

@@ -30,5 +30,6 @@ struct netns_ipv6 {
 	struct netns_sysctl_ipv6 sysctl;
 	struct ipv6_devconf	*devconf_all;
 	struct ipv6_devconf	*devconf_dflt;
+	struct netns_frags	frags;
 };
 #endif

net/ipv4/inet_fragment.c

@@ -174,8 +174,9 @@ int inet_frag_evictor(struct inet_frags *f)
 }
 EXPORT_SYMBOL(inet_frag_evictor);
 
-static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
-		struct inet_frags *f, unsigned int hash, void *arg)
+static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
+		struct inet_frag_queue *qp_in, struct inet_frags *f,
+		unsigned int hash, void *arg)
 {
 	struct inet_frag_queue *qp;
 #ifdef CONFIG_SMP
@@ -189,7 +190,7 @@ static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
 	 * promoted read lock to write lock.
 	 */
 	hlist_for_each_entry(qp, n, &f->hash[hash], list) {
-		if (f->match(qp, arg)) {
+		if (qp->net == nf && f->match(qp, arg)) {
 			atomic_inc(&qp->refcnt);
 			write_unlock(&f->lock);
 			qp_in->last_in |= COMPLETE;
@@ -210,7 +211,8 @@ static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
 	return qp;
 }
 
-static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
+static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
+		struct inet_frags *f, void *arg)
 {
 	struct inet_frag_queue *q;
 
@@ -223,38 +225,39 @@ static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
 	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
 	spin_lock_init(&q->lock);
 	atomic_set(&q->refcnt, 1);
+	q->net = nf;
 
 	return q;
 }
 
-static struct inet_frag_queue *inet_frag_create(struct inet_frags *f,
-		void *arg, unsigned int hash)
+static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
+		struct inet_frags *f, void *arg, unsigned int hash)
 {
 	struct inet_frag_queue *q;
 
-	q = inet_frag_alloc(f, arg);
+	q = inet_frag_alloc(nf, f, arg);
 	if (q == NULL)
 		return NULL;
 
-	return inet_frag_intern(q, f, hash, arg);
+	return inet_frag_intern(nf, q, f, hash, arg);
 }
 
-struct inet_frag_queue *inet_frag_find(struct inet_frags *f, void *key,
-		unsigned int hash)
+struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
+		struct inet_frags *f, void *key, unsigned int hash)
 {
 	struct inet_frag_queue *q;
 	struct hlist_node *n;
 
 	read_lock(&f->lock);
 	hlist_for_each_entry(q, n, &f->hash[hash], list) {
-		if (f->match(q, key)) {
+		if (q->net == nf && f->match(q, key)) {
 			atomic_inc(&q->refcnt);
 			read_unlock(&f->lock);
 			return q;
 		}
 	}
 	read_unlock(&f->lock);
 
-	return inet_frag_create(f, key, hash);
+	return inet_frag_create(nf, f, key, hash);
 }
 EXPORT_SYMBOL(inet_frag_find);

net/ipv4/ip_fragment.c

@@ -236,7 +236,7 @@ static void ip_expire(unsigned long arg)
 /* Find the correct entry in the "incomplete datagrams" queue for
  * this IP datagram, and create new one, if nothing is found.
  */
-static inline struct ipq *ip_find(struct iphdr *iph, u32 user)
+static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user)
 {
 	struct inet_frag_queue *q;
 	struct ip4_create_arg arg;
@@ -246,7 +246,7 @@ static inline struct ipq *ip_find(struct iphdr *iph, u32 user)
 	arg.user = user;
 	hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol);
 
-	q = inet_frag_find(&ip4_frags, &arg, hash);
+	q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash);
 	if (q == NULL)
 		goto out_nomem;
 
@@ -582,15 +582,17 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
 int ip_defrag(struct sk_buff *skb, u32 user)
 {
 	struct ipq *qp;
+	struct net *net;
 
 	IP_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
 
+	net = skb->dev->nd_net;
 	/* Start by cleaning up the memory. */
 	if (atomic_read(&ip4_frags.mem) > ip4_frags_ctl.high_thresh)
 		ip_evictor();
 
 	/* Lookup (or create) queue header */
-	if ((qp = ip_find(ip_hdr(skb), user)) != NULL) {
+	if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) {
 		int ret;
 
 		spin_lock(&qp->q.lock);

net/ipv6/netfilter/nf_conntrack_reasm.c

@@ -78,6 +78,7 @@ static struct inet_frags_ctl nf_frags_ctl __read_mostly = {
 };
 
 static struct inet_frags nf_frags;
+static struct netns_frags nf_init_frags;
 
 #ifdef CONFIG_SYSCTL
 struct ctl_table nf_ct_ipv6_sysctl_table[] = {
@@ -212,7 +213,7 @@ fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst)
 	arg.dst = dst;
 	hash = ip6qhashfn(id, src, dst);
 
-	q = inet_frag_find(&nf_frags, &arg, hash);
+	q = inet_frag_find(&nf_init_frags, &nf_frags, &arg, hash);
 	if (q == NULL)
 		goto oom;
 

net/ipv6/reassembly.c

@@ -234,7 +234,7 @@ static void ip6_frag_expire(unsigned long data)
 }
 
 static __inline__ struct frag_queue *
-fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
+fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst,
 	struct inet6_dev *idev)
 {
 	struct inet_frag_queue *q;
@@ -246,7 +246,7 @@ fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 	arg.dst = dst;
 	hash = ip6qhashfn(id, src, dst);
 
-	q = inet_frag_find(&ip6_frags, &arg, hash);
+	q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 	if (q == NULL)
 		goto oom;
 
@@ -568,6 +568,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
 	struct frag_hdr *fhdr;
 	struct frag_queue *fq;
 	struct ipv6hdr *hdr = ipv6_hdr(skb);
+	struct net *net;
 
 	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 
@@ -598,10 +599,11 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
 		return 1;
 	}
 
+	net = skb->dev->nd_net;
 	if (atomic_read(&ip6_frags.mem) > init_net.ipv6.sysctl.frags.high_thresh)
 		ip6_evictor(ip6_dst_idev(skb->dst));
 
-	if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
+	if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
 			  ip6_dst_idev(skb->dst))) != NULL) {
 		int ret;