6lowpan: add helper to get 6lowpan namespace

This will simplify the new reassembly backport
with no code changes being required.

CC: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: linux-zigbee-devel@lists.sourceforge.net
Cc: David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/net_namespace.h

@@ -373,6 +373,21 @@ static inline void rt_genid_bump_ipv6(struct net *net)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
+static inline struct netns_ieee802154_lowpan *
+net_ieee802154_lowpan(struct net *net)
+{
+	return &net->ieee802154_lowpan;
+}
+#else
+static inline struct netns_ieee802154_lowpan *
+net_ieee802154_lowpan(struct net *net)
+{
+	return NULL;
+}
+#endif
+
+
 /* For callers who don't really care about whether it's IPv4 or IPv6 */
 static inline void rt_genid_bump_all(struct net *net)
 {

net/ieee802154/reassembly.c

@@ -120,6 +120,8 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
 	struct inet_frag_queue *q;
 	struct lowpan_create_arg arg;
 	unsigned int hash;
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
 
 	arg.tag = frag_info->d_tag;
 	arg.d_size = frag_info->d_size;
@@ -129,7 +131,7 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
 	read_lock(&lowpan_frags.lock);
 	hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst);
 
-	q = inet_frag_find(&net->ieee802154_lowpan.frags,
+	q = inet_frag_find(&ieee802154_lowpan->frags,
 			   &lowpan_frags, &arg, hash);
 	if (IS_ERR_OR_NULL(q)) {
 		inet_frag_maybe_warn_overflow(q, pr_fmt());
@@ -357,6 +359,8 @@ int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
 	struct net *net = dev_net(skb->dev);
 	struct lowpan_frag_info *frag_info = lowpan_cb(skb);
 	struct ieee802154_addr source, dest;
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
 	int err;
 
 	source = mac_cb(skb)->source;
@@ -366,10 +370,10 @@ int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
 	if (err < 0)
 		goto err;
 
-	if (frag_info->d_size > net->ieee802154_lowpan.max_dsize)
+	if (frag_info->d_size > ieee802154_lowpan->max_dsize)
 		goto err;
 
-	inet_frag_evictor(&net->ieee802154_lowpan.frags, &lowpan_frags, false);
+	inet_frag_evictor(&ieee802154_lowpan->frags, &lowpan_frags, false);
 
 	fq = fq_find(net, frag_info, &source, &dest);
 	if (fq != NULL) {
@@ -436,6 +440,8 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 {
 	struct ctl_table *table;
 	struct ctl_table_header *hdr;
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
 
 	table = lowpan_frags_ns_ctl_table;
 	if (!net_eq(net, &init_net)) {
@@ -444,10 +450,10 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 		if (table == NULL)
 			goto err_alloc;
 
-		table[0].data = &net->ieee802154_lowpan.frags.high_thresh;
-		table[1].data = &net->ieee802154_lowpan.frags.low_thresh;
-		table[2].data = &net->ieee802154_lowpan.frags.timeout;
-		table[3].data = &net->ieee802154_lowpan.max_dsize;
+		table[0].data = &ieee802154_lowpan->frags.high_thresh;
+		table[1].data = &ieee802154_lowpan->frags.low_thresh;
+		table[2].data = &ieee802154_lowpan->frags.timeout;
+		table[3].data = &ieee802154_lowpan->max_dsize;
 
 		/* Don't export sysctls to unprivileged users */
 		if (net->user_ns != &init_user_ns)
@@ -458,7 +464,7 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 	if (hdr == NULL)
 		goto err_reg;
 
-	net->ieee802154_lowpan.sysctl.frags_hdr = hdr;
+	ieee802154_lowpan->sysctl.frags_hdr = hdr;
 	return 0;
 
 err_reg:
@@ -471,9 +477,11 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
 {
 	struct ctl_table *table;
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
 
-	table = net->ieee802154_lowpan.sysctl.frags_hdr->ctl_table_arg;
-	unregister_net_sysctl_table(net->ieee802154_lowpan.sysctl.frags_hdr);
+	table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
 	if (!net_eq(net, &init_net))
 		kfree(table);
 }
@@ -514,20 +522,26 @@ static inline void lowpan_frags_sysctl_unregister(void)
 
 static int __net_init lowpan_frags_init_net(struct net *net)
 {
-	net->ieee802154_lowpan.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
-	net->ieee802154_lowpan.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
-	net->ieee802154_lowpan.frags.timeout = IPV6_FRAG_TIMEOUT;
-	net->ieee802154_lowpan.max_dsize = 0xFFFF;
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
 
-	inet_frags_init_net(&net->ieee802154_lowpan.frags);
+	ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
+	ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
+	ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;
+	ieee802154_lowpan->max_dsize = 0xFFFF;
+
+	inet_frags_init_net(&ieee802154_lowpan->frags);
 
 	return lowpan_frags_ns_sysctl_register(net);
 }
 
 static void __net_exit lowpan_frags_exit_net(struct net *net)
 {
+	struct netns_ieee802154_lowpan *ieee802154_lowpan =
+		net_ieee802154_lowpan(net);
+
 	lowpan_frags_ns_sysctl_unregister(net);
-	inet_frags_exit_net(&net->ieee802154_lowpan.frags, &lowpan_frags);
+	inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags);
 }
 
 static struct pernet_operations lowpan_frags_ops = {